170 attendants, 3 short courses.
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Toggle Authors vs sessions
A – Acciani : 14 Ahmar : 8 12 Ahzi : 3 12 Alava : 21 Albalawi : 17 Albrecht : 12 Alexeev : 6 Alexis : 2 Allaert : 8 Antretter : 12 Araújo : 11 Arnaud : 2 Arnst : 12 Arslan : 11 Auersperg : 12 Aßmann : 12
B – BELHENINI : 5 BRUNO : 5 Baets : 8 Bailey : 3 7 15 22 Bakri-Kassem : 18 Barink : 6 Barth : 3 12 Bauer : 2 Baum : 10 Bechtold : 13 14 Becker : 18 20 Belov : 4 Benedikt : 11 21 Bieniek : 12 Birner : 16 Bissuel : 7 Bojanampati : 4 Bonitz : 5 Bouyssou : 11 Brand : 21 Brea : 11 Bruch : 8 Bruggi : 13 Brunner : 12 Brunschwiler : 2 10 11 Brückner : 12 Buhl : 20 Byun : 7
C – CHEN : 11 COGAN : 11 COUTURIER : 11 Cabello : 11 Cabral : 11 Cai : 12 Callaghan : 13 Capeáns : 11 Cardanobile : 11 Casper : 7 Cassarly : 6 Casset : 13 Chakrabarty : 1 Chassagne : 3 Chatterjee : 11 Cheng : 10 Chernyakov : 11 Corigliano : 13 Correia : 3 Cvitkovich : 12 Czerny : 8
D – DOMAS : 11 DUBOIS : 11 DUCHAMP : 11 Dai : 14 Dalen : 14 Dasgupta : 15 19 22 Dalverny : 2 Darawsheh : 4 Dauksevicius : 11 Defregger : 6 Degrendele : 8 Desloges : 21 Dhaouadi : 18 Diana : 4 Diatta : 11 Dijk : 2 Dong : 3 Doris : 6 Dressler : 12 15 Driel : 9 11 12 Dudek : 18 20 Dulondel : 2 Duraffourg : 21 Dushaq : 11 Dörfler : 3 Döring : 18
E – Ebert : 12 Eder : 6 Eitner : 12 Elasmi : 8 Elata : 21 Erlbacher : 15 Ernst : 2 12 Estevez : 15 Eveloy : 4 19
F – Faller : 3 Fan : 1 9 11 12 22 Fanget : 13 Faria : 11 Ferro : 11 Fiori : 5 15 Fontainhas : 11 Frankenstein : 18 Fu : 9
G – GARDES : 5 Gaidys : 11 Gallois-Garreignot : 5 Gao : 11 Gardes : 11 Gehring : 20 Gely : 21 Gersem : 7 Gessner : 5 10 Geuzaine : 21 Gielen : 6 Golinval : 12 Gonella : 5 15 Gonzalez : 12 Govindaiah : 15 Goyvaerts : 13 Gromala : 12 16 Grünler : 15 Grünwald : 12 Guyenot : 3 Gwoziecki : 13 Gänser : 12 Górecka-Drzazga : 11 Göken : 6
H – HOANG : 12 HUANG : 11 Halbach : 21 Hammer : 6 12 Han : 16 Hao : 11 12 Haridas : 11 Hartmann : 5 Hattel : 14 Heggen : 5 Heilmann : 12 20 Hermann : 5 Hietschold : 11 Hildebrandt : 18 20 Hildenbrand : 6 Hiller : 11 Hoffmann : 13 Hohlfeld : 13 14 Holzinger : 21 Huang : 11 12 15 Hölck : 2 5 Höppner : 11
I – Iwamoto : 19
J – Jabbari : 14 Jakub : 11 Janicki : 4 Jansen : 2 13 Janssen : 14 Janus : 11 Jarfors : 4 Jing : 11 12 Johlitz : 2 Jones : 14 Joseph : 5
K – KE : 11 KWOK : 3 Kabakchiev : 20 Kang : 10 Kartashova : 11 Kassie : 21 Ke : 11 12 Keller : 2 Kennedy : 19 Khatibi : 8 Kiefl : 18 Kiener : 12 Kirjusha : 11 Koehler : 11 Kotelon : 7 Kougianos : 17 Kozic : 12 Kozlov : 11 Krach : 15 Kraemer : 8 Kraft : 12 Kraker : 6 Kuczynska : 20 Kuczyńska : 20 Kumar : 2 10
L – LEE : 12 LENCZNER : 11 LO : 12 Labie : 8 Lan : 12 Lang : 2 16 Laraqi : 7 Latour : 13 Lauron : 11 Lauwaert : 8 Lederer : 8 Lee : 7 Leisner : 4 Leslie : 19 Lhostis : 15 Li : 9 14 Libot : 2 Lion : 2 Liu : 1 11 12 Lohmeyer : 5 Loureiro : 11 Lu : 11 Lunz : 18 López : 11 Lörtscher : 11
M – MAJEK : 11 Mackenzie : 6 Maffucci : 4 Magistris : 4 Magnani : 4 Magnien : 6 Mahieu : 21 Maier-Kiener : 12 Maj : 11 Majanen : 6 Mann : 5 Mansouri : 13 Markus : 18 Martinez : 2 11 Maskari : 4 Mavinkurve : 2 May : 20 Mayer : 16 Mazloum-Nejadari : 8 McPherson : 16 Mehner : 11 Melz : 16 Meszmer : 11 Michalik : 11 Michel : 12 Middendorf : 16 Milesi : 2 Mininno : 14 Mirbagheri : 15 Mitic : 18 Mitterhuber : 6 Modugno : 14 Mohammed : 11 Mohanty : 17 Monier-Vinard : 7 Montegiglio : 14 Morissette : 12 Moulin : 21 Mukhopadhyay : 19 Myöhänen : 6 Métais : 20 Müller : 12
N – Napieralski : 11 Nasirabadi : 14 Naumann : 21 Ndieguene : 12 Nelhiebel : 20 Nestler : 10 Neutens : 13 Nicolics : 8 12 Niemeier : 12 Niessner : 20 Nikitin : 20 Noels : 12 Normand : 12 Nuster : 12
O – Olkkonen : 6 Onken : 12 Otaibi : 12 O’Reilly : 11
P – PUJOS : 5 Packwood : 14 Palczynska : 16 Paltauf : 12 Pantou : 2 Paola : 6 Paquay : 12 Park : 7 Parry : 15 Patzak : 6 Pawlak : 13 Payandeh : 4 Pettermann : 20 Pfeiler-Deutschmann : 6 Pichler : 15 Piller : 20 Pissoort : 8 Poelma : 1 Poncet : 13 Poveda : 11 Pressel : 20 Prisacaru : 16 Progent : 21 Provent : 5 Pufall : 12 Putnik : 11
Q – QIU : 12 Qi : 14 Qian : 9 11
R – ROQUETA : 5 Ramli : 11 Rasras : 11 Raszkowski : 4 Renault : 11 Rendler : 12 Reuther : 12 Rivadulla : 11 Rivas-Murias : 11 Rocha : 11 Rochus : 13 Rodgers : 4 19 Rodriguez : 11 Roellig : 18 Rogié : 7 Roqueta : 11 Rosc : 6 Rottenberg : 13 Ru : 12 Rzepka : 2 12 18
S – SHANG : 12 Salahouelhadj : 12 Samson : 4 Santhanakrishnan : 7 Santos : 13 Sareło : 11 Sart : 15 Sasi : 11 Schafet : 20 Schindler-Saefkow : 2 10 Schlangen : 1 Schlegel : 12 Schlottig : 2 10 Schmidt : 18 Schrag : 20 Schrank : 6 Schulz : 5 Schulze : 10 Schwerz : 18 Schöngrundner : 12 Schöps : 7 Seebich : 12 Seifikar : 11 Shabunina : 11 Shaporin : 10 Sheremet : 11 Shmidt : 11 Shmulevich : 21 Sitomaniemi : 6 Smilauer : 6 Soestbergen : 2 Sommer : 18 Springer : 20 Stefan : 6 Stegmeier : 18 Steller : 11 Stiebing : 11 Stoyanov : 3 15 Streit : 10 Suhir : 12 16 Sun : 9 11 12 Sundaravadivel : 17 Swartjes : 14 Sylvestre : 12 Szermer : 11
T – TOUGUI : 5 Talnishnikh : 11 Tapaninen : 6 Tassetti : 21 Tchkalov : 11 Thielen : 15 Thierauf : 16 Thonhofer : 11 Tilford : 3 7 15 Tilmans : 13 Todri-Sanial : 4 10 Torres : 10 Tourloukis : 3 15 Treml : 12 Tuinhout : 14
U – Unger : 12
V – Vandenboch : 13 Vandevelde : 8 Vanhee : 8 Varaprasad : 19 Venkatesh : 13 Vernier : 12 Vigne : 21 Vodiunig : 16 Voelkel : 16 Vogel : 11 Voort : 13 Vu : 2
W – WADE : 11 Walter : 2 Wang : 10 11 12 14 Weide-Zaage : 11 Weidner : 18 Weihe : 20 Weiss : 2 8 Wenbo : 6 Werner : 6 Wessén : 4 Wiese : 4 8 12 Willems : 8 Wittler : 2 Wolf : 11 Wolfangel : 20 Wondergem : 6 Wright : 15 Wu : 12 Wunderle : 2 5 10 11 12 20 Wymysłowski : 11
X – Xie : 19 Xu : 11
Y – YANG : 11 YAO : 5 YUEN : 3 11 Yang : 12 Ye : 11 Yongbo : 20 Youssef : 16 Yuile : 4
Z – ZHANG : 11 ZHONG : 3 Zaal : 2 14 Zahn : 11 Zakgeim : 11 Zangl : 3 Zega : 13 Zeijl : 1 Zhang : 1 2 9 10 11 12 13 Zhao : 9 10 11 12 Zhou : 11 12 Zschenderlein : 10 20 Zubert : 4
d – daniel : 7
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Toggle Authors find your schedule
- A. Alexeev: Monday April 18 2016, session 6 at 16:20 (#1)
- A. Wymysłowski: Tuesday April 19 2016, session 11 at 10:30 (poster)
- A.E. Chernyakov: Tuesday April 19 2016, session 11 at 10:30 (poster)
- Abdalla Youssef: Tuesday April 19 2016, session 16 at 16:50 (#4)
- Abdellah Salahouelhadj: Tuesday April 19 2016, session 12 at 10:30 (poster)
- Abhijit Dasgupta: Wednesday April 20 2016, session 22 at 13:30 (#1)
- Adam Yuile: Monday April 18 2016, session 4 at 14:50 (#3)
- Agnieszka Samson: Monday April 18 2016, session 4 at 14:30 (#2)
- Aida Todri-Sanial: Monday April 18 2016, session 4 at 15:10 (#4)
- Alan Wright: Tuesday April 19 2016, session 15 at 14:00 (#2)
- Alexander Kozlov: Tuesday April 19 2016, session 11 at 10:30 (poster)
- Alexander Mann: Monday April 18 2016, session 5 at 17:30 (#4)
- Alexandre Halbach: Wednesday April 20 2016, session 21 at 11:30 (#2)
- Ali Mazloum-Nejadari: Tuesday April 19 2016, session 8 at 09:00 (#1)
- Alicja Palczynska: Tuesday April 19 2016, session 16 at 16:30 (#3)
- Altieri-Weimar, Paola: Monday April 18 2016, session 6 at 17:10 (#3)
- Andreia Faria: Tuesday April 19 2016, session 11 at 10:30 (poster)
- Andrew McPherson: Tuesday April 19 2016, session 16 at 16:10 (#2)
- Arun Sasi: Tuesday April 19 2016, session 11 at 10:30 (poster)
- Assane Ndieguene: Tuesday April 19 2016, session 12 at 10:30 (poster)
- Bart Vandevelde: Tuesday April 19 2016, session 8 at 09:50 (#3)
- Benjamin Métais: Wednesday April 20 2016, session 20 at 12:10 (#4)
- Bingbing Zhang: Monday April 18 2016, session 2 at 15:10 (#4)
- Bo Sun: Tuesday April 19 2016, session 9 at 09:30 (#2)
- Bo Sun: Tuesday April 19 2016, session 12 at 10:30 (poster)
- Cezary Maj: Tuesday April 19 2016, session 11 at 10:30 (poster)
- Changho Byun: Monday April 18 2016, session 7 at 17:30 (#4)
- Cheng Qian: Tuesday April 19 2016, session 9 at 09:00 (#1)
- Christopher Bailey: Wednesday April 20 2016, session 22 at 14:30 (#3)
- Clémence Vernier: Tuesday April 19 2016, session 12 at 10:30 (poster)
- Clément Sart: Tuesday April 19 2016, session 15 at 13:30 (#1)
- D. Hoffmann: Tuesday April 19 2016, session 13 at 14:20 (#3)
- Daniel Markus: Tuesday April 19 2016, session 18 at 16:50 (#4)
- Daohui Li: Tuesday April 19 2016, session 14 at 14:20 (#3)
- Darjan Kozic: Tuesday April 19 2016, session 12 at 10:30 (poster)
- David Leslie: Wednesday April 20 2016, session 19 at 09:30 (#2)
- Dongyue Liu: Tuesday April 19 2016, session 12 at 10:30 (poster)
- E. Suhir: Tuesday April 19 2016, session 12 at 10:30 (poster)
- E. Suhir: Tuesday April 19 2016, session 16 at 15:40 (#1)
- Eric Monier-Vinard: Monday April 18 2016, session 7 at 17:10 (#3)
- Eva Grünwald: Tuesday April 19 2016, session 12 at 10:30 (poster)
- Falk Naumann: Wednesday April 20 2016, session 21 at 12:10 (#4)
- Florian Schindler-Saefkow: Monday April 18 2016, session 2 at 15:30 (#5)
- G. Capeáns: Tuesday April 19 2016, session 11 at 10:30 (poster)
- Giuseppe Acciani: Tuesday April 19 2016, session 14 at 14:40 (#4)
- Guangjun Lu: Tuesday April 19 2016, session 11 at 10:30 (poster)
- Hao Huang: Tuesday April 19 2016, session 15 at 14:40 (#4)
- Hong-Liang Ke: Tuesday April 19 2016, session 12 at 10:30 (poster)
- Ilja Belov: Monday April 18 2016, session 4 at 14:00 (#1)
- Ismail Darawsheh: Monday April 18 2016, session 4 at 15:30 (#5)
- J. Heilmann: Wednesday April 20 2016, session 20 at 12:30 (#5)
- J.B. Libot: Monday April 18 2016, session 2 at 14:00 (#1)
- J.J.M. Zaal: Tuesday April 19 2016, session 14 at 14:00 (#2)
- Jan Albrecht: Tuesday April 19 2016, session 12 at 10:30 (poster)
- Jia-Shen Lan: Tuesday April 19 2016, session 12 at 10:30 (poster)
- Jiajie Fan: Tuesday April 19 2016, session 9 at 09:50 (#3)
- Jian Hao: Tuesday April 19 2016, session 11 at 10:30 (poster)
- Joseph Al Ahmar: Tuesday April 19 2016, session 12 at 10:30 (poster)
- Julien Magnien: Monday April 18 2016, session 6 at 16:50 (#2)
- Krishnendu Chakrabarty: Monday April 18 2016, session 1 at 11:00 (#1)
- Li Carlos Rendler: Tuesday April 19 2016, session 12 at 10:30 (poster)
- Lin Dong: Monday April 18 2016, session 3 at 15:10 (#4)
- Lisa-Marie Faller: Monday April 18 2016, session 3 at 14:00 (#1)
- Liuyang Zhang: Tuesday April 19 2016, session 10 at 09:50 (#3)
- M. Kuczyńska: Wednesday April 20 2016, session 20 at 11:00 (#1)
- M. van Soestbergen: Monday April 18 2016, session 2 at 14:30 (#2)
- M.R.Venkatesh: Tuesday April 19 2016, session 13 at 15:00 (#5)
- Mani Sekaran Santhanakrishnan: Monday April 18 2016, session 7 at 16:20 (#1)
- Martin Benedikt: Tuesday April 19 2016, session 11 at 10:30 (poster)
- Martin Benedikt: Wednesday April 20 2016, session 21 at 12:30 (#5)
- Martin Niessner: Wednesday April 20 2016, session 20 at 11:30 (#2)
- Martin Putnik: Tuesday April 19 2016, session 11 at 10:30 (poster)
- Martin Springer: Wednesday April 20 2016, session 20 at 11:50 (#3)
- Martin Stiebing: Tuesday April 19 2016, session 11 at 10:30 (poster)
- Massar WADE: Tuesday April 19 2016, session 11 at 10:30 (poster)
- Matteo Bruggi: Tuesday April 19 2016, session 13 at 13:30 (#1)
- Michel LENCZNER: Tuesday April 19 2016, session 11 at 10:30 (poster)
- Nancy Iwamoto: Wednesday April 20 2016, session 19 at 09:00 (#1)
- Nicolas Barth: Tuesday April 19 2016, session 12 at 10:30 (poster)
- Nikhil Govindaiah: Tuesday April 19 2016, session 15 at 15:00 (#5)
- Noor Amalina Ramli: Tuesday April 19 2016, session 11 at 10:30 (poster)
- Ole Hölck: Monday April 18 2016, session 2 at 14:50 (#3)
- Olli Tapaninen: Monday April 18 2016, session 6 at 17:30 (#4)
- P. Gardes: Tuesday April 19 2016, session 11 at 10:30 (poster)
- P. López: Tuesday April 19 2016, session 11 at 10:30 (poster)
- P. Meszmer: Tuesday April 19 2016, session 11 at 10:30 (poster)
- Parizad Shojaee Nasirabadi: Tuesday April 19 2016, session 14 at 15:00 (#5)
- Pauline Poncet: Tuesday April 19 2016, session 13 at 14:40 (#4)
- Peter Rodgers: Wednesday April 20 2016, session 19 at 10:00 (#3)
- Petra Streit: Tuesday April 19 2016, session 10 at 09:30 (#2)
- Prabha Sundaravadivel: Tuesday April 19 2016, session 17 at 16:10 (#2)
- R. Dudek: Tuesday April 19 2016, session 18 at 15:40 (#1)
- R.H. Poelma: Monday April 18 2016, session 1 at 12:00 (#3)
- Robert Schwerz: Tuesday April 19 2016, session 18 at 16:30 (#3)
- Roger Schlegel: Tuesday April 19 2016, session 12 at 10:30 (poster)
- Rolanas Dauksevicius: Tuesday April 19 2016, session 11 at 10:30 (poster)
- Romain Chassagne: Monday April 18 2016, session 3 at 14:50 (#3)
- Ruixia Zhang: Tuesday April 19 2016, session 11 at 10:30 (poster)
- Saraju P. Mohanty: Tuesday April 19 2016, session 17 at 15:40 (#1)
- Sebastien Gallois-Garreignot: Monday April 18 2016, session 5 at 17:10 (#3)
- Sébastien Vigne: Wednesday April 20 2016, session 21 at 11:50 (#3)
- Shahabeddin Vamegh E.: Tuesday April 19 2016, session 18 at 16:10 (#2)
- Shai Shmulevich: Wednesday April 20 2016, session 21 at 11:00 (#1)
- Sheng Liu: Monday April 18 2016, session 1 at 11:30 (#2)
- Steffen Hartmann: Monday April 18 2016, session 5 at 16:20 (#1)
- Steffen Wiese: Tuesday April 19 2016, session 8 at 09:30 (#2)
- Stoyan Stoyanov: Tuesday April 19 2016, session 15 at 14:20 (#3)
- T. Bechtold: Tuesday April 19 2016, session 14 at 13:30 (#1)
- T. Tilford: Monday April 18 2016, session 3 at 15:30 (#5)
- T.-V. HOANG: Tuesday April 19 2016, session 12 at 10:30 (poster)
- Thorben Casper: Monday April 18 2016, session 7 at 16:50 (#2)
- Tim Onken: Tuesday April 19 2016, session 12 at 10:30 (poster)
- Umar Albalawi: Tuesday April 19 2016, session 17 at 16:30 (#3)
- Uwe Zschenderlein: Tuesday April 19 2016, session 10 at 09:00 (#1)
- V. Rochus: Tuesday April 19 2016, session 13 at 14:00 (#2)
- Weihai Zhang: Tuesday April 19 2016, session 12 at 10:30 (poster)
- WeiZhen YAO: Monday April 18 2016, session 5 at 16:50 (#2)
- Xing QIU: Tuesday April 19 2016, session 12 at 10:30 (poster)
- XueJun Fan: Wednesday April 20 2016, session 22 at 14:00 (#2)
- Yanpen Liu: Tuesday April 19 2016, session 11 at 10:30 (poster)
- Yinsheng ZHONG: Monday April 18 2016, session 3 at 14:30 (#2)
- Zakriya Mohammed: Tuesday April 19 2016, session 11 at 10:30 (poster)
- Zhibo CHEN: Tuesday April 19 2016, session 11 at 10:30 (poster)
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| Session 2 |
Package level reliability characterisation |
14:00 Salle des Actes |
Monday April 18 2016 |
| Chaired by Rene Poelma |
| 14:00 |
30mn |
Keynote presentation – Mechanical fatigue assessment of SAC305 solder joints under harmonic and random vibrations
J.B. Libot 1, L. Arnaud 2, O. Dalverny 2, J. Alexis 2, P. Milesi 3, F. Dulondel 3
1 University of Toulouse; INP/ENIT; LGP – SAFRAN Sagem
2 University of Toulouse; INP/ENIT; LGP
3 SAFRAN Sagem
abstract  Vibration-induced solder joint fatigue is a main reliability concern for aerospace and military industries whose electronic equipment used in the field is required to remain functional under harsh loadings. Due to the RoHS directive which eventually will prevent lead from being utilized in electronic systems, there is a need for a better understanding of lead-free mechanical behavior under vibration conditions. This study reports the durability of Sn3.0Ag0.5Cu (SAC305) solder joints subjected to harmonic solicitations at three specific temperatures (-55°C, 20°C and 105°C) and random vibrations at ambient temperature (20°C). A test assembly was designed and consisted in a single daisy-chained 1152 I/O ball grid array (FBGA1152) package assembled on a flame retardant (FR-4) printed circuit board (PCB). The vibration levels were imposed by a controlled deflection at the center of the board at its natural frequency. The electric continuity was monitored to determine the number of cycles to failure of each sample. Mode shape measurements with a scanning vibrometer were also conducted and correlated with finite element analysis (FEA) to ensure accurate calculation of strain within the critical solder balls at the corners of the component. The failed specimens were then cross-sectioned in order to determine failure modes. A comparison of SAC305 durability with SnPb36Ag2 solder is given, along with a set of lifetime measurements for two complementary assemblies: 68 I/O Leadless Chip Carrier (LCC68) and 324 I/O Plastic Ball Grid Array (PBGA324). For the tested harmonic vibration levels, SAC305 outperforms SnPb36Ag2. Furthermore, the effect of temperature on the mechanical durability of SAC305 appears to be minor. Failure analysis pointed out different failure modes on PCB and component side, along with pad cratering and copper trace failures. FEA calculations allows the determination of the SAC305 fatigue curve to estimate the high cycle fatigue (HCF) behavior of SAC305 solder under harmonic vibrations. The random vibrations durability of SAC305 solder was assessed using the same test assembly (FBGA1152) which was subjected to three different levels of Power Spectral Density (PSD) at 20°C. The random vibrations tests were conducted within a frequency band ranging from 500 Hz to 900 Hz around the natural frequency. The chosen PSD levels applied were 0.04, 0.10 and 0.20 g2/Hz. Using power-law fitting, the results give a first estimation of the durability of SAC305 solder joints subjected to random vibrations. |
| 14:30 |
20mn |
In-situ cure shrinkage measurement of die attach and underfill materials
M. van Soestbergen, J.L.M. Llacer Martinez, J.J.M. Zaal, A. Mavinkurve, NXP Semiconductors, Nijmegen, Netherlands
abstract We present a robust method for measuring the cure shrinkage of dispensable organic films in-situ. Samples consist of dispensed organic material (e.g. die attach or underfill) sandwiched between a glass substrate and a silicon die. A Thermal Mechanical Analyzer (TMA) was used to accurately measure the displacement of the die during cure, and to control the temperature. An analytical model has been derived to disentangle the thermal shrinkage, and chemical cure shrinkage, which is verified by surface profile measurements (projection Moiré). We show that the measured displacement can be directly related to the cure shrinkage. To verify this methodology we have characterized a commercially available die attach material. The characterization yields a simultaneous measurement of the magnitude of cure shrinkage and the cure kinetics. |
| 14:50 |
20mn |
Ageing phenomena in isotropic conductive adhesive material investigated by ex-perimental and simulation techniques
Ole Hölck 1, Marius van Dijk 1, Jörg Bauer 1, Hans Walter 1, Olaf Wittler 1, Klaus-Dieter Lang 2
1 Fraunhofer IZM
2 TU Berlin
abstract In this work we present our results of an approach to assess material property changes with time due to high temperature ageing in an isotropic conductive adhesive. A molecular model of an epoxy with similar primary chemistry is investigated by molecular dynamics simulations. By variation of crosslink density, one supposed effect of ageing (post-curing) is investigated with respect to its impact on diffusivity of water molecules and the free volume of the epoxy matrix. In a simple submodel of a composite material, the portability of the results into FE simulations and their validity are discussed by comparison to experimental results |
| 15:10 |
20mn |
Aging of Epoxy Moulding Compound – Thermomechanical Properties during High Temperature Storage
Bingbing Zhang 1, Michael Johlitz 1, Alexander Lion 1, Leo Ernst 2, K. M. B. Jansen 3, Duc-Khoi Vu 4, Laurens Weiss 4
1 Institute of Mechanics, Universität der Bundeswehr München, Germany
2 Ernst Consultant, Schoonhoven, Netherlands
3 Department of Design Engineering, Delft University of Technology, Netherlands
4 Infineon Technologies AG, Neubiberg, Germany
abstract It is well known that epoxy moulding compound (EMC) plays an important role in the reliability of electronic packages. In order to predict the mechanical behaviour of electronic packages that are encapsulated with moulding compound, the material properties of EMCs should be carefully characterized and modelled. Currently, more and more components are exposed to severe environments. Among these, high temperature conditions can lead to irreversible changes in EMCs. These changes can be attributed to chemical processes such as oxidation and can lead to degradation of the applied resins, which we refer to here as aging. As a result, the thermo-mechanical properties of the EMCs change severely with time. Due to ongoing changes in the aging EMC of a package, the stress and strain distributions in the package change with time, while embrittlement affects the fracture strength. As a consequence, the long-term reliability of a package is severely affected. Since an appropriate constitutive representation of the material properties of the slowly growing oxidation layers is not available, it is cumbersome to predict the reliability of real packages for long term applications. Being motivated by this limitation, in the present work, we focus on the experimental characterization as well as on the numerical modelling of aging of EMCs at high temperature storage (HTS). As a result the long term stress-strain distribution of a package can be simulated. |
| 15:30 |
20mn |
Master Curve Synthesis by Effective Viscoelastic Plastic Material Modeling
Florian Schindler-Saefkow 1, Remi Pantou 2, Gerd Schlottig 3, Sridhar Kumar 4, Thomas Brunschwiler 3, Juergen Keller 1, Bernhard Wunderle 4, Sven Rzepka 2
1 AMIC Angewandte Micro-Messtechnik GmbH, Berlin, Germany
2 Fraunhofer ENAS, Chemnitz, Germany
3 IBM Research, Rueschlikon, Switzerland
4 Technical University of Chemnitz, Germany
abstract Finite Element Simulations of highly integrated and large electronics packages with detailed elastic-plastic material modeling of thousands of solder balls are still challenging tasks for today’s computation systems. The complex geometry and mesh and the usage of time consuming creep laws for solder materials makes it nearly impossible to calculate different geometries or process parameters. This paper describes a method to reduce the complexity of the mesh in the region of the solder balls and surrounding underfill with one simple block physically described as a viscoelastic material. Therefore a viscoelastic/plastic behavior of a complex unit cell was modeled in a temperature dependent harmonic frequency sweep or relaxation simulation. The reaction of the unit cell was utilized to synthesize the master curve, Prony coefficients and shift function to an effective material model. Finally an error estimation of the unit cell approach was carried out. Therefore a reliability simulation was modeled replacing the solder balls and the surrounding underfill by the effective material.A flip chip on FR4 model with underfill was used to benchmark the effective material model approach against detailed models without any complexity reduction. The results show that the introduced effective material approach can be used to cut down computation time significantly without losing accuracy in life time prediction. |
| Session 3 |
Process Modelling & 3D Printing |
14:00 Theatrum Anatomicum |
Monday April 18 2016 |
| Chaired by Dag Andersson, Nancy Iwamoto |
| 14:00 |
30mn |
Keynote presentation – Robust Design of a 3D- and Inkjet-Printed Capacitive ForcePressure Sensor
Lisa-Marie Faller, Hubert Zangl, Alpen Adria Universität, Klagenfurt, Austria
abstract We present a method to robust design of a capacitive force/pressure sensor, manufactured in rapid prototyping manner, by adaptation of the electrode structure. Rapid prototyping technologies, such as the considered 3D- and inkjet-printing processes, suffer from major uncertainties in geometry and material properties. The presented methodology consequently aims at minimizing the influence of topology and geometry variations as well as measurement noise on the sensor read-out. It is outlined as a consequence of the beneficial combination of a Latin Hypercube design of experiments and the subsequent Linear Bayesian Minimum Mean Square Error (BMSE) estimator. Even though the additional effort in hardware and signal processing is low, we demonstrate a significant improvement of the measurement uncertainty when we move from a single capacitor to an optimized capacitor array. |
| 14:30 |
20mn |
A Multi-scale Simulation Method to Predict Delamination and Adhesion Force in UV-Nanoimprint Lithography
Yinsheng ZHONG, Stephen. C. T. KWOK, Matthew. M. F. YUEN, Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology
abstract Nanoimprint lithography (NIL) provides a low cost process for nano-pattern mass production. Polymer filling and de-molding processes determine the quality of the imprinted pattern in NIL. In UV-nanoimprint lithography, low viscous polymer reduces the requirement of imprint pressure in polymer filling. The interaction between prepatterned mold and UV-curable polymer during demoldinggreatly affect the patterning result. Due to the length scale issues, molecular simulation or traditional finite element method cannot individually simulate the de-molding process. Therefore, a multi-scale approach combining both MD simulation and finite element analysis is proposed to predict the adhesion force between the mold and polymer layer in UV-nanoimprint lithography. The present study is focused on incorporating material behavior at the de-molding interface of nano-patterns. Simulation of molecular dynamics is used to calculate the interfacial energy between the polyvinyl alcohol mold and a methacrylate-based resist layer. A stress-displacement curve can be achieved from the slope of the energydisplacement relation. The result is then utilized tocharacterize the material properties of cohesive zone elements at the finite element model. A contact debonding model is built to simulate the de-molding process. And the model is verified by the results from peel-off experiment. |
| 14:50 |
20mn |
Modeling of the HPC Infiltration Process by means of the Lattice Boltzmann Method
Romain Chassagne, Fabian Dörfler, Michael Guyenot, Robert Bosch GmbH, Corporate Research Division – Robert Bosch Campus, Renningen, Germany
abstract The requirements for next-generation power electronic modules and devices imply enhanced energy densities, i.e., interconnection packaging technologies have to guarantee enhanced ampacity and robustness with respect to thermo-mechanical loads. Particularly, the interconnection layers of semi-conductor devices (e.g. MOSFET, IGBT, diodes) play a predominant role in the robustness of power electronic modules.Diffusion soldering (aka “HotPowCon”, HPC) is a promising alternative with respect to the above mentioned requirements. HPC consists in the infiltration of a solder alloy melt into a porous copper matrix. The resulting intermetallic phases between copper and the soldering alloy have a melting point high above the standard processing and operating temperatures, and hence, a thermo-mechanically stable interconnection layer is formed.A simulation of this infiltration process requires the modeling of wetting dynamics in complex porous structures for which classical computational fluid dynamics (CFD) is limited with respect to computational efficiency. In contrast, the so-called lattice Boltzmann method (LBM), which is an indirect solver of the Navier-Stokes equations based on statistical physics, is numerically far more efficient.In this article, we present a simulation approach based on the LBM in order to model the response of infiltration rates on crucial HPC process parameters like viscosity and wettability of the liquid solder alloy, as well as porosity and geometrical properties of the copper matrix.The simulation results show consistency with the analytic Lucas-Washburn law for capillarity-driven flows in porous media. This can be seen as a proof of concept for the application of the LBM on the HPC infiltration process, and thus, the LBM might be the key-component of a future tool-chain for infiltration process optimization with respect to large-scale production demands. |
| 15:10 |
20mn |
Modeling and Numerical Simulation of Selective Laser Sintering
Lin Dong 1, Nicolas Barth 2, J.P.M. Correia 3, Said Ahzi 2
1 Service Scientifique et Technique, Ambassade de la R.P. de Chine en France, 18–20 rue Washington, 75008 Paris, France.
2 Qatar Environment and Energy Research Institute (QEERI), Hamad bin Khalifa University (HBKU), Qatar Foundation, Doha, Qatar.
3 ICube Laboratory, Université de Strasbourg–CNRS, 2 rue Boussingault, 67000 Strasbourg, France.
abstract Selective Laser Sintering (SLS) is an important branch of additive manufacturing (“3D printing”) technologies. The SLS machines are processing powders so that they are selectively sintered by a CO2 or Nd:YAG laser beam. The SLS process was initially developed to produce polymer-based components. Then, SLS had a breakthrough toward the producing of structurally perfect parts directly from metal powders. The high intensity of the laser beam makes it possible to rapidly heat a small region, inducing a disequilibrium of the temperature distribution and large temperature gradients. The numerical simulation is important for the process of laser sintering since it tackles the comprehension of such local heat accumulation. This, in turn, drives the choice of the process parameters in accordance with the processed material characteristics and with the quality aimed for the final sintered product. In the present paper, we use our three-dimensional transient finite element model to study the SLS process applied to amorphous polycarbonate and titanium powders. |
| 15:30 |
20mn |
Numerical Analysis of Droplet Deposition in Inkjet Printed Electronics Assembly
T. Tilford, S. Stoyanov, G. Tourloukis, C. Bailey, The University of Greenwich, UK
abstract In this paper, a computational approach for the analysis of microscale droplet impact dynamics is presented. The approach is intended to support a condition based monitoring system to enhance quality and reliability of inkjet printed electronics components. The Smoothed Particle Hydrodynamics (SPH) approach of Lucy and Gingold and Monaghan has been used as the basis for the model, with the δ-SPH terms of Marrone et al used to improve handling of the dynamic impact events and the gradient correction terms of Belytschko used to improve the accuracy of interface dynamics.Model validation has been performed through comparison against a macroscale dam break problem and through a microscale analysis designed to determine accurate surface tension-pressure behaviour based on the Young-Laplace relation. The model is used to assess impact of a single drop on a uniform surface and the three dimensional formation of multi-drop layers |
| Session 6 |
Solid State Lighting I |
16:20 Salle des Actes |
Monday April 18 2016 |
| Chaired by Sven Rzepka, Jiajie Fan |
| 16:20 |
30mn |
Keynote presentation – Simulating Light Conversion in mid-power LEDs
A. Alexeev 1, W. Cassarly 2, V. D. Hildenbrand 1, A. Sitomaniemi 3, O. Tapaninen 3, A. Wondergem 1
1 Philips Lighting, Eindhoven, The Netherlands
2 Synopsis Inc., Pasadena, USA
3 VTT, Oulu, Finland
abstract A good understanding of the optical and thermal properties of mid-power LEDs requires an accurate simulation of the light conversion process in the phosphor layer and a good description of the major materials properties. A ray-tracing model for the light conversion process is developed in LightTools and the output is used as input for the thermal model in ANSYS. The results of the optical and thermal simulations using key parameters are compared with the measured values. Depending on the effort used to calibrate the model, deviations of less than ten percent can be achieved. This is typically within the error margin of the experiments. The main source of error is most likely the missing information on the precise optical die properties. |
| 16:50 |
20mn |
Accelerated thermo-mechanical test method for LED modules
Julien Magnien 1, Jördis Rosc 1, Martin Pfeiler-Deutschmann 2, René Hammer 1, Lisa Mitterhuber 1, Stefan Defregger 1, Franz Schrank 2, Elke Kraker 1
1 Materials Center Leoben Forschung GmbH, Leoben, Austria
2 Tridonic Jennersdorf GmbH, Jennersdorf, Austria
abstract High power light emitting diode (LED) has gained more and more importance over the last decade as a long-life general illumination source. To ensure a long-lasting lifetime of the LED module, knowledge about critical failures has to be generated. However, it is extremely time consuming and complicated to assess the failure mechanisms and the reliability of the whole LED system. In this work the focus lies mainly in the investigation of failure modes generated in wire-bonds of phosphor converted (pc) white LED modules. Therefore an accelerated test method was developed, where the time-consuming electrical switching test was transferred into a fast purely thermo-mechanical test. For this purpose, Finite Element simulations representing the thermal effect of an electrical off-switching cycle were performed to compare thermally induced strains and stresses with equivalent purely mechanical stresses causing similar strain/stress scenarios. The experimental setup consisted of a dynamic mechanical analyzer (DMA), where the electrical switching test was transferred into an equivalent accelerated mechanical compression test. Failure analysis methods such as X-Ray computed tomography (XR-CT) and cross section investigations by light microscopy or scanning electron microscopy (SEM) were used to analyze failure modes and to compare both testing setups (electrical vs. mechanical). Additionally, thermal impedance analysis was used to monitor changes in thermal device performance in a non-destructive way. |
| 17:10 |
20mn |
Reliability model of LED package regarding the fatigue behavior of gold wires
Altieri-Weimar, Paola 1, Yuan, Wenbo 1, Annibale, Santana Eder 1, Schoemaker, Stefan 1, Amberger, Doris 2, Höppel, Heinz Werner 2, Mathias, Göken 2
1 Osram Opto Semiconductors GmbH Regensburg, Germany
2 Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Materials Science
abstract In this study the mechanical properties and fatigue behavior of ultra-fine gold wires are investigated by experimental tension fatigue tests and finite element (FE) simulation. Hardening behavior, yield criterion and yield surface of gold wire are determined by tensile tests and force controlled tension fatigue tests. The relationship between plastic strain and loading stress amplitude is determined and the cyclic strain hardening coefficient is calculated. The fatigue data are used to develop a predictive crack model for gold wires bonded in LED packages, based on finite element (FE) stress simulation at temperature cycles (TC). The computer model of the gold wire in the LED package used in the simulation is reconstructed from computer tomography (CT) analysis. The predictive crack model is calibrated using on-line monitoring of LED wire cracks during TC tests. Finally, using the reliability model, the impact of LED package design and material on the wire lifetime is investigated. |
| 17:30 |
20mn |
Optical and thermal simulation chain for LED package
Olli Tapaninen 1, Petri Myöhänen 1, Mikko Majanen 1, Aila Sitomaniemi 1, Juuso Olkkonen 1, Volker Hildenbrand 2, Alexander W.J. Gielen 3, Fidel Valega Mackenzie 3, Marco Barink 3, Vit Smilauer 4, Borek Patzak 4
1 VTT Technical Research Centre of Finland Ltd., Oulu, Finland
2 Philips Lighting Solutions, Eindoven, Netherlands
3 TNO Technical Sciences, Eindoven, Netherlands
4 Czech Technical University in Prague, Prague, Czech Republic
abstract This paper presents a test case for coupling two physical aspects of an LED, optical and thermal, using specific simulation models coupled through an open source platform for distributed multi-physics modelling. The glue code for coupling is written with Python programming language including routines to interface specific simulation models. This approach can also be used for any other software. The main optical simulations are performed with an open source ray tracer software and the main thermal simulations are performed with Comsol Multiphysics. We show how to connect a Mie theory based scattering calculator with the ray tracer. Simulation results are compared to measured samples. The total radiant power emitted by the modelled LED is shown to be up to 3% consistent with the measurements. |
| Session 7 |
Thermal Modeling and Characterization |
16:20 Salle Dugès |
Monday April 18 2016 |
| Chaired by Marcin Janicki, Uwe Zschenderlein |
| 16:20 |
30mn |
Keynote presentation – On the Application of Topology Optimisation Techniques to Thermal Management of Microelectronic systems
Mani Sekaran Santhanakrishnan, Timothy Tilford, Christopher Bailey, University of Greenwich, London, United Kingdom
abstract In this paper, an autonomous thermal management design process based on a topological optimisation algorithm is presented. The numerical framework uses a finite element multiphysics solver to assess fluid flow and heat transfer, coupled with the Method of Moving Asymptotes approach for topology optimisation. The design framework is utilised to develop a copper heatsink for a simplified electronics package at two differing Reynolds numbers. In both cases, the final shape resembles a tree like structure rather than a more conventional fin structure. |
| 16:50 |
20mn |
Automatic Generation of Equivalent Electrothermal SPICE Netlists from 3D Electrothermal Field Models
Thorben Casper, Herbert De Gersem, Sebastian Schöps, Institut für Theorie Elektromagnetischer Felder, Technische Universität Darmstadt, Darmstadt, Germany
abstract Starting from a 3D electrothermal field problem discretized by the Finite Integration Technique, the equivalence to a circuit description is shown by exploiting the analogy to the Modified Nodal Analysis approach. Using this analogy, an algorithm for the automatic generation of a monolithic SPICE netlist is presented. Joule losses from the electrical circuit are included as heat sources in the thermal circuit. The thermal simulation yields nodal temperatures that influence the electrical conductivity. Apart from the used discretization, this approach applies no further simplifications. Disregarding the temperature dependence of the electrical conductivity, an example 3D chip package is used to validate the algorithm. |
| 17:10 |
20mn |
State of the Art of Numerical Thermal Characterization of Electronic Component
Eric Monier-Vinard 1, Brice Rogié 2, Valentin Bissuel 1, Najib Laraqi 2, Olivier daniel 1, Marie-Cécile Kotelon 3
1 Thales Global Services, Velizy-Villacoublay, France
2 Université Paris Ouest, Laboratoire LTIE, Ville d’Avray, France
3 Université Paris XIII, Sorbonne Paris Cité, Villetaneuse, France
abstract Latest commercial Computational Fluid Dynamic tool allow modelling more finely the conjugate thermo fluidic behaviour of a single electronic component mounted on a Printed Wiring Board. A realistic three-dimensional representation of a large set of electric copper traces of its composite structure is henceforth achievable.So it is possible to confront the predictions of a fully detailed numerical model of an electronic board to a set of experiment results in order to judge of their relevance.The present work demonstrates that the numerical model discrepancy is lower than 2% for a large set of boundary conditionsMoreover the practical modelling assumptions, such as effective thermal conductivity calculation, used, since decades, for characterizing the thermal performances of an electronic component were checked and appeared to very tricky. New approaches must be developed.Further the establishment of a realistic numerical model of electronic components permits to properly apprehend multi-physics design issues |
| 17:30 |
20mn |
Thermal dynamic modeling of laser diode cooling system considering surrounding ambient temperature
Changho Byun 1, Sangki Park 2, Yonghan Lee 2, Sun-Kyu Lee 2
1 LG Electronics, 84, Wanam-ro, Seongsan-gu, Changwon-si, Gyeongsangnam-do, Republic of Korea
2 Dept. of Mechatronics, Gwangju Institute of Science and Technology (GIST), 123 Cheomdangwagi-ro, Buk-gu, Gwangju 61005, Republic of Korea
abstract Laser-driven white lighting consists of blue laser diode (LD) and yellow phosphor, and it is attracting attention as a future lighting technology due to its advantages such as high luminous intensity, efficacy and the possibility of miniaturization. The optical efficiency of LD is highly affected by the temperature, cooling system is critical for many practical applications such as automotive headlamp. This study presents a single phase liquid cooling system which was selected for both higher cooling performance and lower consumption power. Also, a thermal dynamic model was proposed for predicting the LD temperature with experiment to validate the model. The system consists of an LD, heat spreader, heat sink and liquid pump. A heat spreader was designed with liquid cooling channels based on the model in consideration of both the thermal resistance and pressure drop. Also, the effect of surrounding ambient conditions was analyzed for considering real vehicle situation. |
| Session 11 |
Posters : Multi-Physics Issues in Microelectronics |
10:30 Atrium |
Tuesday April 19 2016 |
| Chaired by Bernhard Wunderle, Kaspar Jansen |
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Modelling of thermal processes in catalytic gas microsensors implementing a measurement of combustible gas concentration
Alexander Kozlov, Omsk State Technical University, Omsk, Russia
abstract Thermal processes in catalytic gas microsensors consisting of the micromachined sensitive and reference elements are considered. The modelling procedure for determining the weighted mean temperatures in the elements of the microsensors is proposed. The 2D structure of each element is divided into the regions. The heat differential equation for the regions has the identical form and takes into account two ways of heat power generation: by heater and by catalytic layer. The specific heat power generated in the regions by the heater is determined from consideration of the processes in the Wheatstone bridge circuit with the catalytic gas microsensor. To find the specific heat power generated in the regions with the catalytic layer during oxidation of combustible gas the similarity theory is used. The temperature distribution in the regions is found by using the eigenfunction method and iteration procedure which allows the temperature dependencies of the parameters to take into account. For the catalytic gas microsensor implementing a measurement of methane concentration the following characteristics were determined: the output voltage of the bridge circuit with the catalytic gas microsensor as a function of the methane concentration in air; the dependencies of the weighted mean temperature of the micro-hotplate for each element and the heat power generated in elements on the methane concentration. |
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Study of the Shielding of Angular Position Sensors with Magnetic Transduction
Andreia Faria 1, José Fontainhas 2, Diógenes Araújo 2, Jorge Cabral 1, Luís Alexandre Rocha 3
1 ALGORITMI CENTER, Universidade do Minho, Campus de Azurém, Guimarães, Portugal
2 Bosch Car Multimedia, Braga, Portugal
3 CMEMS-UM Universidade do Minho, Campus de Azurém, Guimarães, Portugal |
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Analytical, numerical and experimental approach to analysis properties of a silicon membrane pressure sensor
A. Wymysłowski, A. Górecka-Drzazga, K. Sareło, Wroclaw University of Technology, Faculty of Microsystem Electronics and Photonics, Wroclaw, Poland
abstract There are more and more sophisticated sensors inmicrosystem applications, which seem to rivet theengineers’ attention. There is an extraordinary variety ofsensors types which includes pressure, temperature,acceleration processing, optical, magnetic, chemical etc.In a number of sensors the critical sensing element mostoften is made of a silicon. The mechanical properties ofsilicon are outstanding and techniques for shaping it intocomplex three-dimensional structures are well known andmastered from the technological point of view.Most often MEMS sensor are integral part of anyelectronic system. The main attention of the currentresearch was MEMS silicon pressure sensor based on anoptical detection of a membrane deflection, which can beused for a pressure detection in harsh environment. Thegoal of the work was to apply a numerical simulationalong with an analytical analysis, which were finallyfollowed up and validated by the experimental results inorder to define the sensor RSM (Response SurfaceModels) model, which can be used directly in complexnumerical prototyping of electronic systems using, e.g.SPICE/VERILOG type of simulators. |
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Simulation of Moisture Diffusion in Polymers Using Thermal-Moisture Analogy
Arun Sasi, Robert Bosch Engineering and Business Solutions Limited (RBEI), Bangalore, India
Dr. Gromala Przemyslaw Jakub, Robert Bosch GmbH, Automotive Electronics, Tuebingerstr. 123, 72762, Reutlingen, Germany
abstract The present paper illustrates moisture diffusion using advanced thermal-moisture analogy approach. Experimental procedure to measure the diffusivity and solubility of epoxy based encapsulation material to be implemented in simulation has been discussed. The moisture weight gain of the sample is measured till its saturated state over time at 5 different relative humidity (RH%) and temperature combination. Then %weight gain as a function of time results are fitted with the analytical solution of 3-D diffusion equation using nonlinear regression analysis to obtain the diffusivity property. Since the saturated concentration at the boundary of the polymer can be described by Henry’s law i.e. Csat = SPvp, where S is solubility (kg /m3/ Pa) and Pvp is the ambient vapor pressure (Pa), which is related to RH% and the saturated vapor pressure Pvp,sat as Pvp=RH%* Pvp,sat; this relation is used to obtain modified solubility and solubility at each temperature. The temperature dependence of solubility and diffusivity are described by Arrhenius relation. The results are utilized in Finite Element (FE) analysis of the moisture diffusion model. Only Fickian moisture absorption has been attempted to be modeled. It has been shown that the moisture diffusion properties obtained from such characterization technique fits satisfactorily with the experimental results. Further the analogy scheme’s degree of simplicity, boundary conditions and applicable situations have been highlighted. |
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Macro model of capacitive MEMS accelerometer in Cadence environment
Cezary Maj 1, Michal Szermer 1, Andrzej Napieralski 1, Bohdan Kirjusha 2, Alexei Tchkalov 2, Piotr Michalik 3
1 Departement of Microelectronics and Computer Science, Lodz University of Technology, Lodz, Poland
2 National Technical University of Ukraine, Kyiv Polytechnic Intitute, Insitute for Applied Systems Analysis, Kiev, Ukraine
3 Universitat Politecnica de Catalunya, Electronic Engineering Department, Barcelona, Spain
abstract Designing of MEMS devices requires modeling step. Many devices combines mechanical and electrical domains. Very often it is desired to use one simulation tool that allows taking into account both domains. Such functionality has CADENCE environment. In this paper we do such simulations using developed macro model of capacitive MEMS accelerometer. The accelerometer is described in Verilog-A language and placed in electrical schematic that consist of read-out circuit. The simulations were performed for the device z-axis CMOS-integrated acceleration sensor that has been developed in UPC Barcelona. The results of simulations were compared to those obtained by measurements of fabricated device. |
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Modeling and simulation of electromechanical-contact based elastomeric pressure sensor
Zhibo CHEN, Wei HUANG, Xinfeng ZHANG, Matthew M.F. YUEN, Hong Kong University of Science and Technology, Hong Kong
abstract Elastomeric electric-contact pressure sensors in wearable devices for monitoring physiological signals have much broader potential. In order to design and develop better pressure sensors, the simulation of the electric contact – pressure response is very important. However, due to the large deformation of the patterned surface, it is difficult to model the specific contact surface by using the conventional electric-contact theory only. In the present study, a hybrid electromechanical-contact resistance model was developed to study the strain and stress distributions on the microstructured elastomeric electric-contact surface subjected to pressure. In our new model, the contact resistance in an epidermal pressure sensor can be modeled easily and accurately with a better result. Our model can be used to optimize the sensor design and evaluate the sensing performance of pressure sensors. |
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Criteria of Unpredictable Failure for High-Power InGaN LEDs
A.E. Chernyakov 1, N.A. Talnishnikh 1, A.L. Zakgeim 1, A.P. Kartashova 2, N.M. Shmidt 2, E.I. Shabunina 2
1 Submicron Heterostructures for Microelectronics Research
2 Ioffe Physical Technical Institute, RAS
abstract The results of the degradation study of commercial InGaN/GaN LEDs with the external quantum efficiency (EQE) ~ 40-50 % at 450-460 nm are presented. It has been clarified that one of the mechanisms responsible for EQE degradation and the unpredictable failure of LEDs is the multiphonon recombination of carriers. The distorted forward branch of I-V characteristics at U < 2V and the appearance of the SI ~j4 section on the current spectral noise density dependences on current density in LEDs before or after 100 hours of aging test are the criteria identifying an unpredictable failure. |
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High frequency characterization of hybrid nanocomposite materials based on simulation and measurement of buried capacitors
Massar WADE, Geneviève DUCHAMP, Tristan DUBOIS, Isabelle BORD MAJEK, University of Bordeaux – IMS Laboratory, Talence, France
abstract Passive components embedded into printed circuit boards (PCBs) are of great interest to enhance the size reduction, the integration density increase and the number of functionalities of electronic circuits. This technology enables to increase the operating frequency towards higher frequencies and improve the reliability. A large number of passive components used on an electronic board are capacitive. So their study involves the biggest challenge for burying into PCBs due to the large range of capacitance required and the large frequency domain of applications. This paper deals with the high frequency characterization and the determination of the frequency dependence of the permittivity of innovative dielectric nanocomposite materials involved in capacitive structures, based on simulations and measurements. |
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Thermo-mechanical simulation to optimize the integration of a BST stacked MIMIM capacitor
P. Gardes, F. Roqueta, M. Diatta, P. Martinez, F. Lauron, E. Bouyssou, P. Poveda, STMicroelectronics, Tours, France |
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A Novel Approach for Colour Shift Investigation on LED-based Luminaires
Guangjun Lu 1, W.D. van Driel 2, Jiajie Fan 1, Cheng Qian 3, Huaiyu Ye 2, Xuejun Fan 4, G.Q. Zhang 2
1 Beijing Research Center, Delft University of Technology, Beijing, China
2 Delft University of Technology, EEMCS Faculty, Delft, the Netherlands
3 State Key Laboratory of Solid State Lighting, Changzhou, China
4 Department of Mechanical Engineering, Lamar University, Beaumont, TX 77710, USA
abstract Luminous flux maintenance and colour stability are two important factors to evaluate the long term reliability, which are always concerns of some potential consumers and hence prevent use in some degree. DOE Energy Star Program requires that the change of chromaticity over the lifetime of the product shall be within 0.007 on the CIE 1976 (u’,v’) diagram. Unlike traditional incandescent lighting products, colour shift mechanisms of LED lighting are complex due to consisting of several different components, and each of them may limit the long term stability and contribute to the colour shift differently during operation. Some studies have been done on the colour shift effects and mechanisms of LED packages, reflectors and diffusers. However, literature on the colour shift study of LED-based luminaire level is little publicly available, especially for the colour shift prediction during design and operation. This paper will propose a view factor approach for colour shift prediction on LED- based luminaires. |
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Thermal-Electric-Mechanical Simulation of a Multilevel Metallization System
Yanpen Liu, Kirsten Weide-Zaage, IMS-RESRI University Hannover, Hannover, Germany
abstract In modern metallization systems mechanical stress due to CTE mismatch is one of the reliability problems. With the help of finite element simulations the thermal-electrical-mechanical behavior can be calculated. The use of a reference temperature for the stress free state in the simulations is insufficient to determine the stress field in the metallization. The intrinsic stress resulting from the processing is hereby not considered. The simulation of the process steps by the birth and die capability of ANSYS is time consuming and complex. A possibility to consider the intrinsic stress in the metallization system is the use of averaged CTEs from measurements of a multi-level stack depending on the horizontal running direction of the interconnect in the x- or y-direction, or in from literature. The values were taken for a comparison between calculated stress field of the stacked metallization system with process steps and the reference temperature for the stress free state.The achieved simulation results help for a better understanding of the stress behavior. |
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Stiffening of higher modes in doubly-clamped beam resonators depending on ground state amplitude
Martin Putnik 1, Stefano Cardanobile 1, Christian Höppner 2, Jan Mehner 3
1 Robert Bosch GmbH, Reutlingen, Germany
2 Bosch Sensortec GmbH, Reutlingen, Germany
3 Chemnitz University of Technology, Chemnitz, Germany
abstract Doubly-clamped beams offer an ideal structurefor studying nonlinear mechanical coupling betweendifferent vibrational modes. Until now, there is lack ofexperimental data concerning the stiffening of highermodes induced by the ground mode. In this paper, weconstruct virtual experimental data for the nonlinearmechanical coupling of in- and out-of-plane modes ofa doubly-clamped beam resonator using full transientFEM simulations. We find a very good agreementof the simulation results with a formula derived forin-plane modes by Owers-Bradley, Lulla et al. Finally,we generalize the formula to include out-of-plane modes,and show that also this case can be correctly described. |
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Stress Investigations in 3D Integrated Silicon Microstructures
Martin Stiebing 1, Emanuel Lörtscher 2, Wolfram Steller 3, Dietmar Vogel 4, M. Jürgen Wolf 3, Thomas Brunschwiler 2, Bernhard Wunderle 1
1 Technische Universität Chemnitz
2 IBM Research – Zurich
3 Fraunhofer IZM – ASSID
4 Fraunhofer ENAS
abstract With the anticipated slow-down of Moore’s Law in the near future, three-dimensional (3D) packaging of microelectronic structures would enable to further increase the integration density required to meet the forecasted demands of future exa-scale computing, cloud computing, big data systems, cognitive computing, mobile communication and other emerging technologies. Throughsilicon vias (TSVs) are a pathway to provide electrical connections for signaling and power-delivery through 3D stacked silicon (Si) microstructures. TSVs and related structures such as ,e.g., interconnects and redistribution lines, however, induce stress in their proximity, namely upon electrochemical deposition and subsequent annealing, the latter due to the large mismatch in the coefficient of thermal expansion between Si and the TSV-filling materials used. Stress-induced crowding and relaxation of the Si lattice can cause a variety of issues ranging from active-device performance degradation, interfacial delamination or interconnect failures to cracking of the entire Si microstructures at stress hotspots upon assembly or operation. Employing a novel dual-shell Si interposer concept with both power delivery and signaling through TSVs, we aim at removing the heat dissipated from the active components sitting on top of one interposer shell through embedded liquid-cooling cavities, a strategy that generically enables true 3D stacking but may also induce additional stress. In the current paper, we reduce system complexity and first investigate, both experimentally and theoretically the TSV-induced stress profiles in one Si interposer half before introducing cooling cavities and sealing structures. After each processing step, the residual and non-thermal stress profile around the TSV is determined using a confocal Raman microscope with sub-micrometer spotsize acting as a local strain gauge. These measurements are conducted under ultra-silent conditions, revealing an unprecedented resolution of 0.01 cm^-1, corresponding to approx. 4.3 MPa of stress in crystalline Si. A detailed comparison of measurements and finite element analysis (with the later taking into account geometry and material properties) is provided, revealing both a good qualitative and quantitative correlation between theory and experiment. We also show that athermal stress after copper deposition can be minimized during an annealing step. |
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Temperature control of an SThM micro-probe with an heat source estimator and a lock-in measurement
Michel LENCZNER 1, Bin YANG 1, Scott COGAN 1, Stéphane DOMAS 1, Du KE 1, Raphaël COUTURIER 1, David Renault 2, Bernd Koehler 3, Pawel Janus 4
1 FEMTO-ST, UFC-CNRS-UTBM-ENSMM, Besançon, France
2 ODESIM, Morre, France
3 Fraunhofer-Institut, IKTS, Dresden, Germany
4 Instytut Technologii Elektronowej, Warsaw, Poland
abstract In view of qualitative temperature measurement by scanning thermal microscopy, we introduce a model-based control law for a new microfabricated probe. The underlying model is the time-space two-scale electro-thermal model presented in this conference in 2015, since it has the power to represent transcients of harmonic modulations. The control method accounts for an estimation of the heat source in the sample and for the delay in the lock-in filter based observation. Experiment-based model calibration is a prerequisite and is discussed in detail. |
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Design and Modelling of Digital MEMS Varactor for Wireless Application.
Noor Amalina Ramli 1, Tughrul Arslan 1, Nakul Haridas 2, Wei Zhou 2
1 University of Edinburgh, Edinburgh, UK
2 Sofant Technologies, Scottish Microelectronics Centre, Edinburgh, UK
abstract This paper presents the design and simulation of a 4-bit digital MEMS varactor with high capacitance ratio. The proposed varactor design consists of four beams over a co-planar waveguide (CPW) line. A new truss beam design is proposed in order to reduce the spring constant of conventional solid beam structure which results in pull-in voltage of 24.3V making it suitable for low loss phase shifters and tunable filters. A linear capacitance step is realized by varying the contact area between the CPW line and the beam based on binary weighted bit design. The width and the length of each beam is fixed to 50 μm and 550 μm respectively to ensure similar pull-in voltage for all beams. To improve the reliability of the design in terms of dielectric charging, side pull-down electrode and a new stopper design is introduced. The existence of the stopper would prevent a direct contact between the beams and the pull-down electrode. A high capacitance ratio of 35.7 is achieved through the implementation of a deep trench of 26.35 μm on the silicon substrate which decreases the parasitic and fringing field capacitance. 16 different capacitance states ranging from 95 fF to 3.4 pF are realised. The overall size of the varactor is 740 μm × 603 μm. The CPW line and the beams are made from 2 μm thick aluminium, while 0.25 μm thick silicon nitride is used as the dielectric layer. The mechanical simulation of the design is carried out using Coventorware 2008, while the characterization of the RF performance is conducted using CST Microwave Studio. |
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Design for Maximum Power Transfer Efficiency of Thermoelectric Generators using Mixed Mode Simulations
G. Capeáns 1, P. López 1, E. Ferro 1, A. García Loureiro 1, D. Cabello 1, F. Rivadulla 2, B. Rivas-Murias 2
1 Centro Singular de Investigación en Tecnoloxías da Información (CiTIUS), Universidade de Santiago de Compostela, Spain
2 Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Universidade de Santiago de Compostela, Spain
abstract Coupled simulations of both thermal and electrical processes are employed to perform reliable estimations of the harvesting capabilities of a novel thermoelectric generator concept based on the use of p- and n-type materials films of nanometric thickness separated by a dielectric layer. The doping and geometrical parameters of the device are optimized to maximize the thermoelectrical properties while guaranteeing optimal power transfer efficiency with the use of mixed mode simulations in conventional CAD tools. |
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Study of the Thermoelectric Properties of Non-Typical Semiconductor Materials with Conventional CAD Tools
P. López 1, A. García Loureiro 1, E. Ferro 1, V.M. Brea 1, B. Rivas-Murias 2
1 Centro Singular de Investigación en Tecnoloxías da Información (CiTIUS), Universidade de Santiago de Compostela, Spain
2 Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Universidade de Santiago de Compostela, Spain
abstract Computer-aided design (CAD) simulation tools offer the advantage of integrating both thermal and electrical simulations facilitating the study of new materials and structures. In this work, we demonstrate the possibility of using conventional electron devices simulation tools to study the thermoelectrical properties of non-typical semiconductor materials, which allows to do predictive parametric analysis of novel device structures without costly experiments. This is illustrated without loss of generality for scandium nitride and strontium titanate. The simulated results are in good agreement with those reported in the literature. |
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Raman based stress analysis of the active areas of a piezoresistive MEMS force sensor – experimental setup data processing and comparison to numerically obtained results
P. Meszmer 1, K. Hiller 2, R.D. Rodriguez 3, E. Sheremet 4, D.R.T. Zahn 3, M. Hietschold 4, B. Wunderle 1
1 Technische Universität Chemnitz, Faculty for electrical engineering and information technologies, Chair materials and reliability of microsystems, D-09107 Chemnitz
2 Technische Universität Chemnitz, Center for Microtechnologies ZfM, D-09107 Chemnitz
3 Technische Universität Chemnitz, Physics Department, Chair Semiconductor Physics, D-09107 Chemnitz
4 Technische Universität Chemnitz, Physics Department, Chair Solid Surfaces Analysis, D-09107 Chemnitz |
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Comparison of lifetime predictions with LED lamps and light source modules in accelerated aging tests
Jian Hao 1, Qiang Sun 2, Lei Jing 2, Yao Wang 2, Jian Zhao 2, HongXin Zhang 2, Hongliang Ke 1, Qun Gao 2, Xiaoxun Wang 2, Yanchao Zhang 2
1 University of Chinese Academy of Science
2 Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences
abstract In order to investigate the difference of the lifetime predictions between LED lamps and light source modules, different types of accelerated aging tests have been done in this paper. The accelerated temperatures are 85 ℃, 80 ℃ and 60 ℃ for three aging tests, respectively. Luminous flux, as evaluation criteria of degradation, is measured at accelerated aging temperatures. Fitted by the exponential decay law of luminous flux, decay rate of each sample is acquired. Under the condition of Weibull distribution, two-stage method is used to solve the degradation model and to calculate the accelerated lifetimes of LED. The lifetimes at room temperature of 25℃ are then calculated by use of the Arrhenius model. It is shown that the widths of confidence intervals of parameters of Weibull distribution are improved greatly by the second stage of simulation. The averaged confidence interval of shape parameter is about 3% of that in the first stage of estimate. The medium lifetime at room temperature of LED lamp declines by 5.6% as compared with light source module. This implies that the aging of driver module has small influence on lifetime of LED lamp. |
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Numerical study of near-optimal parameters of polymeric encapsulation layer containing a periodic array of piezoelectric nanowires used for force sensing
Rolanas Dauksevicius 1, Rimvydas Gaidys 1, Eoin P. O’Reilly 2, Masoud Seifikar 2
1 Kaunas University of Technology, Kaunas, Lithuania
2 Tyndall National Institute, University College Cork, Cork, Ireland
abstract This paper presents the results of finite element modeling and analysis of a dynamically loaded array of individually addressable vertical ZnO nanowires (piezo-pixels) encapsulated in a polymer, which is intended to function as a pressure sensor having the purpose of identification of fingerprints with very high spatial resolution. Two multiphysics models were implemented by formulating different conditions of mechanical interfacial coupling between the nanowires and the surrounding polymer (with and without contact interactions). Parametric simulations were conducted in order to predict near-optimal values of polymer Young’s modulus and layer thickness in terms of magnitude and variability of electrical signals generated by the nanowires. Numerical results also revealed the impact of different system parameters and load conditions on the electrical response of the nanowires. |
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Lifetime Evaluation Methods for LED products
Ruixia Zhang, Chenzhao Zhang, Dongyue Liu, Min Zhao, Jie Huang, Lisheng Xu, Hebei Semiconductor Research Institute, Shijiazhuang 050051, China |
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Guidelines for Enabling Modular Simulations According to Signal-based Subsystem Modelling
Martin Benedikt, Stefan Thonhofer, VIRTUAL VEHICLE Research Center, Graz, Austria
abstract The implementation of a modular system development approach offers great opportunities for distributed modelling and analysis of mechatronic systems.Signal-flow based subsystem models are frequently used for this purpose, especially within Co-Simulation scenarios. They are usually masked such that sharing the model is possible without granting access to internal details of the implementation. However, this lack of knowledge about the internal structure of a model can lead to modelling mistakes: especially problems originating from neglected energy exchange between models can happen. Such problems can be avoided if physical interaction based models are used for defining the interfaces of the models. This contribution highlights typically occuring problems according modular system simulation leading to modelling guidelines, demonstrated on a simple theoretical example. |
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Bi-axial Highly Sensitive ±5 g Polysilicon based Differential Capacitive Accelerometer
Zakriya Mohammed 1, Ghada Dushaq 2, Aveek Chatterjee 3, Mahmoud Rasras 1
1 Masdar Institute of Science and Technology, Abu Dhabi, UAE
2 Masdar Institute of Science and Technology
3 MEMS Department, GlobalFoundries, Singapore
abstract This paper demonstrates the design and simulation of a 2-axis capacitive accelerometer. The design utilizes a simple comb structure to detect capacitance change with a minimum gap spacing of 0.9 μm. By optimizing the design and anti-gap spacing, the device is designed to yield high capacitance change with the proof mass displacement. Initial simulation results show a displacement sensitivity of 0.02μm/g (g=9.8 m/s2) and a differential capacitance sensitivity (scale factor) of 68 fF/g. The sensitivity achieved is best among the devices of its range (± 5g) and dimensions (2×2mm2). This device is being fabricated by GlobalFoundries-Singapore. |
| Session 12 |
Posters : Thermal and Thermo-Mechanical Issues in Microelectronics |
10:30 Atrium |
Tuesday April 19 2016 |
| Chaired by Bernhard Wunderle, Kaspar Jansen |
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CTE measurements for 3D package substrates using Digital Image Correlation
Abdellah Salahouelhadj, Mario Gonzalez, Imec, Leuven, Belgium
abstract Thermo-mechanical stresses are often induced during processing of IC-packages. This is mainly due the Coefficient of Thermal Expansion (CTE) mismatch between the materials used to make these packages. Therefore, accurate CTE measurements is of great importance. In this study in-plane CTE measurements were conducted for thin film samples using Digital Image Correlation (DIC). The methodology was validated using copper test samples. Two different package substrates were characterized. DIC technique was compared to Thermal Mechanical Analysis (TMA) technique. The CTE measured by DIC is about 25-33% higher than TMA.Finally, some experimental and numerical tests were conducted to assess errors related to DIC technique. Both numerical and experimental tests, based on rigid-body motion were conducted. They allow to assess the errors related to lighting, the optical lens distortion, the noise due to CCD sensor and heat radiation, the out-of-plane displacement and the correlation algorithm. |
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In-Situ Solder Surface Tension Measurements Using Mechanical Resonances
Assane Ndieguene 1, Jean-François Morissette 1, Nathalie Normand 2, Julien Sylvestre 1
1 Department of Mechanical Engineering, Université de Sherbrooke (Sherbrooke, QC, Canada)
2 IBM Bromont (Bromont, QC, Canada)
abstract We propose a method for in-situ measurements of the surface tension of solder joints on microelectronics chips. The method uses actual chips placed in an inert atmosphere, in a heating chamber with a transparent lid. A confocal microscopy probe is used to oberve the top of solder balls through the lid while a piezoelectric actuator induces vibrations in the system. The setup allows the measurement of the resonance frequencies of the balls by comparing the system’s response to sweeps in excitation frequency, for temperatures below and above the liquidus temperature of the solder joints. A number of phenomena were observed, such as undercooling during solidification and continuous formation of surface oxydes. |
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Lumen Decay Prediction in LED Lamps
Bo Sun 1, Xuejun Fan 2, Willem van Driel 3, Thomas Michel 2, Jiang Zhou 2, Guoqi Zhang 1
1 Delft University of Technology
2 Lamar University
3 Phillips
abstract Lumen decay of LEDs is affected by time, junction temperature and input current. In LED lamps, both temperature and input current vary with time due to driver’s degradation and temperature change of lamps. This paper proposes a lumen decay prediction method which considers effects of operation time, temperature and current by taking the interaction of LED and driver performance into account. In particular, a lumen decay model for LED source with consideration of the ever changing current and temperature is developed and validated experimentally. Several scenarios are analyzed theoretically by applying different assumptions. |
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Reliability of a dual-curable adhesive bond
Clémence Vernier, Marc Dressler, Hans-Peter Seebich, Bernhard Wunderle, Robert Bosch GmbH, Schwieberdingen, Germany
abstract This project aims at evaluating the reliability of a dual-curable adhesive bonded joint used in optical applications. The delamination at the interface adhesivesubstrate is one of the most critical failure modes: once a crack is initiated, it propagates catastrophically even at small loads. The fracture toughness is tested statically and cyclically using state of the art methods. In addition, the use of an electrodynamic shaker to increase the collected data is analyzed: testing on the shaker permits testing several samples at a time and is a flexible tool to vary the applied load and frequency. An accurate determination of the material properties and the curing mechanisms is necessary to transfer load capacity values into strength values. It has been shown that the adhesive can be considered as linear visco-elastic up to 10% of the maximum strain. The samples for the shaker can be manufactured reproducibly and a first test gives promising results for the application of this instrument for the study of crack initiation and propagation on several geometries. |
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Interface crack propagation between Epoxy Molding Compound and Copper lead frame
Weihai Zhang 1, Daoguo Yang 1, Leo Ernst 2, Bingbing Zhang 3, Wen Yang 1, Miao Cai 1
1 Guilin University of Electronic Technology, China
2 Ernst Consultant, Schoonhoven, The Netherlands
3 Institute of Mechanics, Universität der Bundeswehr München, Germany
abstract For the MMB delamination experiments on CU-EMC interfaces as previously discussed in [1-6], the interfacefracture shows the characteristics of a “brittle interface”. This is because of the fact that the actual fracture appears between the brittle EMC and the brittle CU-oxides (being present on the CU lead-frame). Low cycle fatigue fracture or sub-critical fracture under cyclic loading conditions is generally considered not to be occurring for “brittle interfaces”. Therefore, it was somewhat surprising that in [7] fatigue fracture was reported to occur for CU-EMC interfaces. The reason for this surprising behaviour could possibly be found in theoverloading of the CU-substrate above its yield limit or just due to local plastic phenomena in the CU near thecrack tip. In such a case the J-Integral value at the crack tip could possibly rise even under non-progressive cyclic loading.In order to research this phenomena for the MMB test of [1-6], a number of cyclic deformation simulations isapplied to explore the J-Integral value for the case that the CU-lead-frame is being bend above its yield limit. In this paper following steps will be discussed: 1- As during non-progressive cyclic loading extremelysmall changes of the J-Integral value are expected to occur and these should be well registered, first aseparate comparison of the J-integral evaluation of the MMB test for 3 different FEM packages is discussed (ANSYS, ABAQUS, MARC). 2- The simulation results for the J-Integral values during non-progressive cyclic loading at room temperature (=Glassy state of the EMC), are evaluated. It occurs that Shake down to Elastic action occurs after the first cycles. As a result, based on the simulation results at room temperature, sub-critical fracture is not likely to occur. It is expected that at high temperatures (=Rubbery state of the EMC) again Shake down to Elastic action will occur after the first few cycles. Consequently, plastic behaviour in the CU is not considered as the root cause of sub-critical fracture. On the other hand, in packages under cyclic loading including high temperature, the exposure at high temperature will be accompanied by continuing aging of the EMC. In parallel research [15] it was found that due to aging of the EMC the deformation andstress state of a package is dramatically changing with time. This dramatically changing state couldwell be the origin of previously observed sub-critical fracture. Here further research will be required. |
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Fracture and Material Behavior of Thin Film Composites
Darjan Kozic 1, Ruth Treml 2, Verena Maier-Kiener 3, Ronald Schöngrundner 1, Roland Brunner 1, Daniel Kiener 2, Thomas Antretter 4, Hans-Peter Gänser 1
1 Materials Center Leoben Forschung GmbH, Leoben, Austria
2 Department Materials Physics, Montanuniversität Leoben, Leoben, Austria
3 Department Physical Metallurgy
4 Institute of Mechanics, Montanuniversität Leoben, Leoben, Austria
abstract Nanoscale, multi-material thin film structures are commonly used in the design of microelectronic devices. Composites like these have the advantage of occupying a small volume in a specific device which makes a realization of 3D integrated circuits easier. Nonetheless, an arbitrarily fabricated thin film component will not automatically meet the requirements concerning its reliability and persistent functionality. In this paper, we investigate the fracture behavior of a micro-cantilever, where a copper (Cu) layer is sandwiched between two tungsten (W) layers on a silicon (Si) substrate. The crack driving forces through the layer structure are calculated for linear elastic and elastic-plastic material behavior with and without hardening and will crucially depend on the used material properties. This is especially the case when the crack tip is located in the vicinity of a sharp interface, where the material properties will change abruptly. The stress-strain relation for W and Cu is calculated by fitting simulation results to data from spherical nanoindentation experiments. Due to the arrangement and material properties of the material layers, a crack oriented perpendicular to the interfaces and propagating through the thin film system will be arrested in the Cu-interlayer. |
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Parameter Identification for Interface Delamination Processes in Molded Electronic Packages
Roger Schlegel 1, Axel Müller 1, Roland Niemeier 1, Przemyslaw Jakub Gromala 2
1 Dynardo GmbH, Weimar, Germany
2 Robert Bosch GmbH, Automotive Electronics, Reutlingen, Germany
abstract The goal of the documented analysis is the buildup of an appropriate mechanical model and the parameter identification for the shear button test. The test has been performed at different hammer positions in order to identify the shear and tensile strength parameter of the interface between mold compound and copper substrate.The parameter identification process contains a sensitivity analysis and fit-optimization which was carried out with optiSLang. To simulate the crack behavior of the interface and the mold compound the material library multiPlas is applied that uses multi-surface plasticity models at continuum element level.Finally a parameter set has been identified that allows for the fitting of all test shear forces. In addition to the interface and crack properties the contact modeling at the hammer tip has been found as a key factor for a successful identification of the model parameter. Other than expected this is especially true for the high hammer positions and can be explained by a local stress resp. a local contact problem. Here also the strength properties of the mold compound play an important role. |
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Power Core (PC) Embedding a Plurality of IC Devices and Sandwiched Between Two Insulated Metal Substrates (IMS’): Predicted Thermal Stresses
E. Suhir 1, M. Unger 2, L. Cvitkovich 2, J. Nicolics 2
1 ERS Co. Los Altos, USA
2 Institute of Sensor and Actuator Systems, TU Wien, Vienna, Austria
abstract Power core (PC) sandwiched between two insulated metal substrates (IMS) and embedding active and passive IC devices is currently viewed as an attractive advanced packaging option having a strong potential in the automotive industry and beyond. A natural reliability concern, however, is the level of the thermally induced stresses in a multi-material assembly of the type in question. Accordingly, an analytical (mathematical) stress model is developed for the evaluation of these stresses. The stresses include normal stresses acting in the crosssections of the assembly components, and the shearing and peeling stresses acting at the interfaces of these components and at the embedded devices. The model can be helpful in the stress analysis and physical design of the assemblies, in which the PC is sandwiched between two IMS’. It can be used also in other areas of engineering, where tri-material assemblies comprised of dissimilar materials and subjected to the change in temperature are employed. The general concepts are illustrated by a detailed numerical example. The analysis is an extension of the study carried out earlier for a bow-free assembly. It is noteworthy that although the calculations are carried out for the case when the assembly is cooled down from an elevated temperature to a low temperature, the developed model is equally applicable to any change in temperature, as long as the linear approach is used and the stresses are proportional to the change in temperature, whatever its sign or the magnitude is. |
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Characterization of Polyimid-Multi-Layer Thin Films Combining Laser Ultrasonic Measurements and Numerical Evaluations
Eva Grünwald 1, Robert Nuster 2, Renè Hammer 1, Heiko Aßmann 3, Günther Paltauf 2, Roland Brunner 1
1 Materials Center Leoben Forschung GmbH, Leoben, Austria
2 University of Graz, Graz, Austria
3 Infineon Dresden GmbH, Dresden, Germany |
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A Study Of Dry Stiction Phenomenon In MEMS Using A Computational Stochastic Multi-scale Methodology
T.-V. HOANG 1, L. Wu 1, S. Paquay 2, J.-C. Golinval 1, M. Arnst 1, L. Noels 1
1 Department of Aerospace and Mechanical Engineering, University of Liège, Belgium
2 Open Engineering SA, Belgium
abstract This work studies the uncertainties of the adhesive contact problems for reduced size structures, e.g. the stiction failure of microelectromechanical systems (MEMS). In MEMS, the surfaces forces, such as van der Waals forces and capillary forces, are dominant in comparison with the body forces. As these force magnitudes strongly depend on the contact distance, when the two contacting surfaces are rough, the contact distances vary, and the physical contact areas are limited at the highest asperities of the contacting surfaces. Therefore, the adhesive contact forces between two rough surfaces can suffer from a scatter, and the involved structural behaviors can be indeterministic. To numerically predict the probability behaviors of structures involving adhesion, the computational stochastic model-based multi-scale method developed by the authors is applied. |
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Junction temperature estimation for LED lamp with forward voltage method
Hong-Liang Ke, Qiang Sun, Jian Zhao, Hong-Xin Zhang, Lei Jing, Yao Wang, Jian Hao, Department of Optoelectronics Research and Development Center, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Chang Chun, China
abstract For estimating the junction temperature (Tj) of LED lamp, the Tj of LED module powering by rated current (135mA DC) and working in the thermal environment of LED lamp is measured with traditional forward voltage method in experiment 1. To calculate the Tj of LED lamp in actual working conditions (220V AC), a correction factor is introduced into the original model to process thedeviation of output currents of LED driver electronics, as demonstrated in experiment 2. Compared with the surface temperature of LED obtained by infrared imaging method, the result in experiment 2 can effectively reflect the change in Tj of LED lamp under different ambient temperatures, which differs the surface temperature by 3~4℃. While due to a significant effect on the thermal environment of LED lamp introduced by LED driver electronics, the result in experiment 1 is approximately 9~10℃ lower than that in experiment 2. |
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Risk Assessment of Bond Pad Stacks: Combined utilization of Nanoindentation and FE-Modeling
Jan Albrecht 1, Georg Reuther 2, John Brückner 1, Jürgen Auersperg 1, Sven Rzepka 1, Reinhard Pufall 2
1 Micro Materials Center at Fraunhofer ENAS, Technologie-Campus 3, 09126 Chemnitz, Germany
2 Infineon Technologies AG, Am Campeon 1-12, 85579 Neubiberg, Germany
abstract Wire bonding as well as wafer probing can lead to oxide layer cracking. In combination with metal migration electrical failures may occur. Loading conditions comparable to the wire bonding process can be achieved using a nanoindenter. In this work a spherical tip has been used at first to determine material properties of the silicon nitride film and also to attain cracking of the film material. Based on the experimental results a finite element model using ABAQUS standardTM was established representing the experimentally observed load-displacement behavior. The introduction of the extended finite element method as well as the cohesive surface approach allow to describe different failure modes. The results of these investigations can be used to avoid failures like oxide layer cracking during wire bonding or during the wafer testing process. |
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Simulation of Micro-bump Interconnections Failure Analysis for 2.5D IC Packaging
Jia-Shen Lan, Mei-Ling Wu, National Sun Yat-sen University, Taiwan (R.O.C.)
abstract This paper provides micro-bump fracture analysis in the context of a 2.5D IC package under reflow process. With the increasing demands for product functionality, the pitch size and diameter of micro-bumps have become smaller, as a means of achieving higher input/output counts in microelectronic packages. However, by decreasing micro-bump diameter, integrity of the microelectronic package is becoming compromised. The majority of research on the system in package (SiP) has focused on the Coefficient of Thermal Expansion (CTE) mismatch and heat junctions. The primary problems arising due to CTE mismatch and heat dissipation are failures or fatigues in 2.5D IC package, which can escalate to critical reliability issues. However, thermo-mechanical stress induced by temperature loading has a significant effect on material strength, causing, for example, interfacial cracking or micro-bump failure. Thus, 2.5D IC package modeling needs to be developed in order to identify factors that can mitigate micro-bump failure under reflow process. In this paper, we discuss the different insights pertaining to physics of thermo-mechanical loading for 2.5D IC package. |
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Crack Experiments on Multilayer Ceramic Capacitors and Fracture Mechanics Analysis
Joseph Al Ahmar, Steffen Wiese, Saarland University
abstract This paper presents results of fracture tests on Multilayer Ceramic Capacitors (MLCCs). Fracture mechanical calculations were carried out with ANSYS in order to analyse the experimental values of fracture strength for the tested MLCCs. Subsequent metallographic analyses were used to get a precise picture of the origin and the propagation of the crack through the component. |
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Mechanical Stress in Solar Cells with Multi Busbar Interconnection – Parameter Study by FEM Simulation
Li Carlos Rendler 1, Achim Kraft 1, Christian Ebert 2, Ulrich Eitner 1, Steffen Wiese 3
1 Fraunhofer Institute for Solar Energy Systems ISE, Heidenhofstraße 2, 79110 Freiburg, Germany
2 SCHMID Group | Gebr. SCHMID GmbH, Robert-Bosch-Str. 32-36, 72250 Freudenstadt, Germany
3 Saarland University, Microintegration and Reliability, Campus A5 1, 66123 Saarbruecken, Germany
abstract The interconnection of silicon solar cells is commonly realized by soldering copper ribbons or wires with a solder coating onto screen-printed silver contacts. Due to the difference of the coefficient of thermal expansion (CTE) of copper and silicon, thermomechanical stress is induced after the soldering process during cooling down to room temperature. In the first part of this work, a model is introduced based on the Finite Element Method (FEM) to determine the influence of crucial interconnector properties on the deformation of a section of a silicon solar cell with Multi Busbar (MBB) layout, connected on one side. The deformation is easy to measure and serves as a visible indicator for the mechanical stress in the solar cell. We determine the diameter of the wire to have the largest influence on the cell deformation. However, it has to be taken into account that, if the wire diameter is changed also the number of wires for the interconnection of an entire MBB solar cell has to be adapted. Moreover, the considerable influences of the Young’s modulus and the yield strength of the copper wire on the cell bow are shown.Additionally, the results of a FEM model to determine the distribution of the thermomechanical stress in a MBB solar cell, connected on both sides, are shown. The stress distribution in the interconnecting wires reveals that they undergo plastic deformation during the cooling down to room temperature after the solder process. We determine maximum tensile stress values in the wires of about 162 MPa, located adjacent to the outermost pads of a pad row on the front side or a pad group on the back side of the MBB solar cell. In addition, we find areas with large tensile stresses within the silicon solar cell. Due to the stress level near the outermost pads on both sides of the MBB solar cell we expect these areas to be most sensitive to defects like cracks in the silicon or adhesive failures of the pad metallization. |
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Research on test method of thermal resistance and junction temperature for LED modules
Dongyue Liu, Zhiqin Ru, Fang Liu, Chenzhao Zhang, Jie Huang, Hebei Semiconductor Research Institute, Shijiazhuang, China
abstract Until now, there has not yet been a standardized method for the LED module thermal resistance measurements. This directly affects the lifetime assessment of the LED modules. By testing and studying the temperature coefficient of the LED modules with different structures, it is found that the temperature coefficient of the LED module follows a linear relationship with voltage when an appropriate test current is applied. In this paper, we investigate the feasibility of measuring the thermal resistance of the LED module as a whole. Furthermore, we propose a method to estimate the junction temperature of the LED module based on the thermal resistances of each of its individual LED and the module itself. This method provides an important basis for the junction temperature calculation in the assessment of the lifetimes of the LED module. However, since the LED module usually has a large surface, the uncertainties existing in the materials and fabricating process will result in a distributed temperature within the LED module. And in most cases, the first failure occurs in the chip with the highest junction temperature. Therefore, the next step of our research will focus on the evaluation of the maximum junction temperature of the LED module based on the proposed method. |
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Towards Thermal Fatigue Modeling of Photovoltaic Panels Under the Gulf Region Harsh Atmospheric Conditions
Nicolas Barth 1, Saïd Ahzi 1, Zaid S. Al Otaibi 2
1 Qatar Environment and Energy Research Institute (QEERI), Hamad bin Khalifa University (HBKU), Qatar Foundation, Doha, Qatar
2 National Center for Solar Energy Technology, King Abdulaziz City for Science and Technology (KACST), Riyadh, Saudi Arabia
abstract An uncoupled thermal and thermo-mechanical modeling of a solar panel is presented. The thermal modeling itself has been previously developed to assess the nominal performance of photovoltaic panels under various service conditions. Within this computational tool, assessing temperatures makes it also possible to analyze the thermal stresses. To study and predict the long-term reliability of the solar panel materials, the thermal cycling due to varying atmospheric conditions is then of particular interest. We undertake such multi-physics approach by taking into account the thermal cycling at the front side of the photovoltaic device packaging, including the solar cells, their antireflective coating, a glass layer and an eventual encapsulating polymer. Even within a simplified modeled design and an elastic constitutive behavior, we can evaluate the threshold to fatigue for most of these materials. |
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Investigation of EMC and SMC leadframes on reliability for UV LED applications
Xing QIU 1, Jeffery C. C. LO 2, Andrew W. SHANG 1, S. W. Ricky LEE 3
1 Department of Mechanical and Aerospace Engineering, Hong Kong University of Science
2 Center for Advanced Microsystems Packaging, Hong Kong University of Science
3 Center for Advanced Microsystems Packaging, HKUST LED-FPD Technology R&D Center
abstract Conventional packaging materials for light-emitting diodes (LED) are susceptible to UV radiation and high temperature. Therefore, for developing UV LED packages, new materials with better UV and high temperature resistance are required. There are two candidates, namely, epoxy molding compound (EMC) and silicone molding compound (SMC), being considered by the industry. This paper focuses on the change in reflectance of EMC and SMC over time as a measure of reliability. Aging was performed on EMC and SMC culls under high temperature, and combination of UV exposure and high temperature simultaneously. Reflectance of EMC and SMC culls before and after aging were compared. It was concluded that both EMC and SMC degrade under simultaneous UV radiation and high temperature aging, and that SMC is more UV and thermally resistant than EMC based on change in reflectance, surface morphology, and roughness. |
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High Cycle Fatigue Testing and Modelling of Sputtered Aluminium Thin Films on Vibrating Silicon MEMS Cantilevers
Tim Onken 1, Jens Heilmann 1, Tomasz Bieniek 2, Reinhard Pufall 3, Bernhard Wunderle 1
1 Technische Universität Chemnitz, Lehrstuhl Werkstoffe und Zuverlässigkeit mikrotechnischer Systeme, Chemnitz, Germany
2 Instytut Technologii Elektronowej, Warsaw, Poland
3 Infineon Technologies AG, Neubiberg, Germany |
| Session 13 |
Modelling and Optimisation for MEMS Structures |
13:30 Theatrum Anatomicum |
Tuesday April 19 2016 |
| Chaired by Alberto Corigliano, Véronique Rochus |
| 13:30 |
30mn |
Keynote presentation – Optimization of Auxetic structures for MEMS applications
Matteo Bruggi, Valentina Zega, Alberto Corigliano, Politecnico di Milano
abstract Complex inertial Micro Electro Mechanical Systems (MEMS) usually require the simultaneous motion of the masses in more than one direction and an overall linear behaviour. Furthermore, since it is usually very difficult to actuate the device in all the required directions, complex spring configurations for the conversion of the motion are needed. Here we present possible solutions to this problem through auxetic structures.The goal of the work is to propose a new topology optimization procedure which can be used as a tool during the design phase of the optimal auxetic structure, that is completely compatible with the MEMS fabrication processes available so far and that allows the motion conversion in a MEMS device without entering the non-linear regime. |
| 14:00 |
20mn |
Design of a MZI Micro-Opto-Mechanical Pressure Sensor for a SiN Photonics Platform
V. Rochus 1, R. Jansen 1, J. Goyvaerts 1, G. Vandenboch 2, B. van de Voort 1, P. Neutens 1, J. O’ Callaghan 1, H.A.C. Tilmans 1, X. Rottenberg 1
1 imec, Belgium
2 KUL, Belgium
abstract This paper presents the design of Micro-Opto-Mechanical Pressure Sensors (MOMPS), which can exhibit much improved sensitivity and noise performance compared to their piezoelectric and capacitive counterparts. As the output intensity variation depends on multiple design parameters, such as the radius of the membrane, the position of the waveguide, the wavelength and the phase variation due to the opto-mechanical coupling, we first derive an analytical model which allows to predict the response of the total system. We then use a Finite Element opto-mechanical model to evaluate the variation of the effective refractive index due to the modification of the optical material properties created by mechanical stress as well as to the waveguide shape deformation. Finally, the sensitivity of the device for a single loop MOMPS and for spiral loops configuration is analyzed. |
| 14:20 |
20mn |
Design Optimization of MEMS Piezoelectric Energy Harvester
D. Hoffmann, T. Bechtold, D. Hohlfeld, Institute of Electronic Appliances and Circuit Technology, University of Rostock, Germany
abstract This work presents an optimization strategy towards extending the operational frequency range of piezoelectric MEMS energy harvesting devices. We propose to use coupled micromechanical resonators to enable efficient energy harvesting at multiple frequencies with a single device. The proposed design, obtained by optimization algorithms, exhibits closely spaced eigenfrequencies with equal power delivery. |
| 14:40 |
20mn |
Design and realization of electroactive polymer actuators for transparent and flexible haptic feedback interfaces
Pauline Poncet 1, Fabrice Casset 1, Antoine Latour 2, Fabrice Domingues Dos Santos 3, Sébastien Pawlak 4, Romain Gwoziecki 2, Stéphane Fanget 1
1 CEA-LETI, MINATEC Campus, Grenoble, France
2 CEA-LITEN, DTNM, LCEI, Grenoble, France
3 ARKEMA-PIEZOTECH, Pierre Benite, France
4 WALTER PACK, Bizkaia, Spain |
| 15:00 |
20mn |
Electro-thermal analysis and design of a combined MEMS impedance and micro hotplate device for gas sensing applications
M.R.Venkatesh 1, B.El Mansouri 2, J.Wei 2, A.Bossche 2, G.Q.Zhang 2
1 Delft University of Technology, Beijing Research Center, State Key Laboratory of Solid State Lighting, Beijing, China
2 Delft University of Technology, ECTM, Delft,The Netherlands
abstract In this paper, we present electro-thermal analysisand design of a combined MEMS micro hotplate andinterdigitated-capacitance impedance sensor for gassensing application using nano-porous materials likemetal organic framework (MOF) .The effects of designparameters of interdigitated electrodes such aswidth(W) and gap(G) of the capacitor, metallizationratio, number of electrodes and area of the capacitor.The influence of height of the electrode material,thickness of the insulation layer between thecapacitance electrodes and the micro hotplateelectrodes are studied. These design parameters areoptimized to obtain a high bare capacitance of theelectrodes using analytical and electric and thermaldomain simulations in COMSOL 5. The design andthermal analysis of the micro hotplate for a temperaturerange of (150-300°C) and low power consumption ismodelled and results are discussed. |
| Session 14 |
Multi-Physics, Electro-Magnetic and Moisture Analysis |
13:30 Salle des Actes |
Tuesday April 19 2016 |
| Chaired by Mike Röllig, Paola Altieri-Weimar |
| 13:30 |
30mn |
Keynote presentation – Multi-Physical Simulation of High Performance Computing Platform Integrating Polymer Waveguides
T. Bechtold, D. Hohlfeld, Institute for Electronic Appliances and Circuit Technology, University of Rostock, Germany
abstract This work presents a general simulation approach forall relevant physical effects in electro-optical circuitboards. Such printed circuit boards integrate electrical components and connections together with optical waveguides as signal lines for applications in data transmission and sensing. The proposed modelling approach includes a calculation of heat distribution based on convective cooling and the thermally induced mechanical stress. We also present results on mode shapes within straight and uniformly curved waveguides as well as a consideration of ray tracing. |
| 14:00 |
20mn |
A novel electrical-mechanical simulation flow to predict stress-induced circuit shifts
J.J.M. Zaal 1, J.H.J. Janssen 1, H.P. Tuinhout 1, R. van Dalen 2, F.H.M. Swartjes 1
1 NXP Semiconductors
2 Ampleon; formerly NXP Semiconductors
abstract In this paper we present an approach to provide insight in electrical parameter shifts due to mechanical stress by means of mechanical modelling through FEA. A fast assessment of the expected parameter shift as a function of location and current direction with respect to stressors can directly be made using the FEA tool. Additionally the results can be exported for usage in electrical circuit simulation tools such as Cadence ADE. The link with such tools enables a more detailed investigation into the effects of stress on parts of the circuit and potential amplification of small shifts. Simulated results based on a test case involving solder bump induced stress are compared with measurements on dedicated high resolution test chips. The measurements show a good correlation with the simulation results, both qualitatively and quantitatively. |
| 14:20 |
20mn |
Mulitphysics Simulation in High Power IGBT Module Design
Daohui Li, Matthew Packwood, Fang Qi, Yangang Wang, Steve Jones, Xiaoping Dai, Power Semiconductor R
abstract High power Insulated Gate Bipolar Transistor (IGBT) modules have been utilised in power electronics industrial applications, such as electrical vehicle, traction, renewable energy, et al. The power module with higher power density, higher voltage and current rating, higher switching frequency, higher operation temperature and much lower/higher storage temperature with lower cost is the development tendency driven by the highly competeting market. The standard 3.3kV/1500A single switch IGBT module with 190mmX140mm footprint has been re-designed using latest multiphysics simulation packages together with novel assembly processes and materials to consider electro-magnetic(EM) design, such as partial discharge, low parasitic inductance of module; to design and optimise thermal, mechanical performance of the module. |
| 14:40 |
20mn |
Multi-physics simulation of a wind piezoelectric energy harvester validated by experimental results
Giuseppe Acciani, Filomena Di Modugno, Ernesto Mininno, Pasquale Montegiglio, Politecnico di Bari, Bari, Italy
abstract In the last decade, an increasing production of wireless micro sensors and small electronic devices has been observed. Their wide diffusion has required a growing interest and appropriate studies towards their powering with untraditional suppliers. Good proposals to satisfy this need have been provided by Energy Harvesting (EH), as process that allows the conversion of natural vibrations into electric energy. In this field the use of piezoelectric materials is developing rapidly and a copious number of applications has been reached both in large and small-scale, especially with piezoelectric transducers stressed by natural vibrations, such as those induced by rain or wind. The studies about harvester devices are often sustained by suitable simulations that reproduce the transducers and their behavior under induced-vibrations accurately. The oldest simulations were based on an isolated observation of physical phenomena. In the last years, the growing development of more sophisticated and performing softwares, based on Finite Element Analysis (FEA) and on Finite Element Method (FEM), is opening new frontiers to simulation environments which are able to reproduce multiphysics phenomena, as they fulfill in nature really. In this scenery, the aim of this paper is to evaluate the behavior and performances of a piezoelectric cantilever beam subjected to wind induced-vibrations. The evaluation is carried out both with an experimental and simulated apparatus and the comparison of data provided in the two situations allows the validation of simulation environment by experimental results. This is an improvement in the modeling of harvester devices simulated in a multiphysics situation that reproduces an interaction between a laminar flow of a fluid and an electrostastic phenomenon, due to piezoelectric effect. Several modeling and simulations of harvester devices in the situation described have been presented recently but they were often lacking an experimental validation. In this paper, the device under examination is a cantilever beam made of one layer of Polyvinylidene fluoride (PVDF) sandwiched between two layers of silver. The modeling and simulation of the energy harvester is based on the model proposed by Bhuyan et al. The experimental setup was reproduced with the FEM software Comsol Multiphysics. In the simulation environment the wind is modeled as a fluid that can flow in a rectangular channel, entering through the inlet with an initial velocity, moving with a laminar flow, and leaving the channel through the outlet. The harvester device is modeled inside the channel and can deform because of the interaction with the flowing fluid. The device reacts to fluid-wind pressure with a deformation that develops electric potential. The mathematical model of the harvester device subjected to wind-induced vibrations is described with the Navier-Stokes equations and the constitutive equations of piezoelectric materials to model wind and piezoelectric behavior respectively. The coefficients characterizing the elasticity matrix, the coupling matrix, and the dielectric matrix peculiar of PVDF were calculated applying the relations between the coefficients appearing in the four sets of constitutive equations for piezoelectric material proposed by IEEE Standard of Piezoelectricity to the coefficients known in literature. |
| 15:00 |
20mn |
Numerical Simulation of Transient Moisture and Temperature Distribution in Polycarbonate and Aluminum Electronic Enclosures
Parizad Shojaee Nasirabadi, Masoud Jabbari, Jesper H. Hattel, Process Modelling Group, Department of Mechanical Engineering, Technical University of Denmark Nils Koppels Allé, 2800 Kgs. Lyngby, Denmark
abstract The challenge of developing a reliable electronic product requires huge amounts of resources and knowledge. Temperature and thermal features directly affect the life of electronic products. Furthermore, moisture can be damaging for electronic components. Nowadays, computational fluid dynamics (CFD) analysis has been proven as a useful tool to exploit the detailedand visualized information about the fluid flows; and hence it can be helpful for predicting local climate inside the electronic enclosures. In this study, the temperature and moisture distributions inside an idealized electronic enclosure with some heat producing components are investigated. It is shown how the enclosure material can influence local climate inside the enclosure using transient numerical simulations. The effect of heat transfer coefficient and wall thickness of the enclosure is also investigated. The enclosure material and the heat transfer coefficient of the enclosure with the environment are found to be influential on the mean temperature and relative humidity; however, the significance of their effects are not the same at different levels. Natural convection plays a key role in RH and temperature distribution. |
| Session 15 |
Advanced Simulation techniques |
13:30 Salle Dugès |
Tuesday April 19 2016 |
| Chaired by Michel Lenczner, Rene Metasch |
| 13:30 |
30mn |
Keynote presentation – Numerical and experimental investigations on the direct hybrid bonding of CuSiO2 patterned surfaces using a cohesive zone model
Clément Sart 1, Rafael Estevez 2, Vincent Fiori 3, Sandrine Lhostis 3, Guillaume Parry 2, Roberto Gonella 3
1 Université Grenoble-Alpes; STMicroelectronics, Crolles; SIMaP, Grenoble INP/Université Joseph Fourier, France
2 Université Grenoble-Alpes; SIMaP, Grenoble INP/Université Joseph Fourier, France
3 STMicroelectronics, Crolles, France
abstract Among the numerous ways to process 3D stacking of integrated circuits, a promising method is the use of Cu/SiO2 hybrid bonding, which enables simultaneous mechanical and electrical connections with an interconnection pitch limited only by photolithography resolution and alignment accuracy. In this work, we present a finite element model of the bonding of Cu/SiO2 patterned surfaces with the aim of identifying the main design and process parameters thought to affect the bonding quality, namely the pad size, shape and layout, dishing, and misalignment. We show that metal pad design induces local perturbations in the propagation of the bonding front and that the bonding quality is governed by the metal density, while pad shape, size and distribution are of little influence. This finding would allow to feed the design rules manual for hybrid bonding interconnects with drawing specifications. This analysis enables to identify the most influent factors and provide guidelines to improve bonding quality at room temperature and thereby help secure integration of 3D stacked IC products. |
| 14:00 |
20mn |
Simulating wafer bow for integrated capacitors using a multiscale approach
Alan Wright 1, Florian Krach 2, Nils Thielen 1, Saeideh Grünler 1, Tobias Erlbacher 3, Peter Pichler 3
1 Fraunhofer IISB, Erlangen, Germany
2 Chair of Electron Devices, University of Erlangen-Nuremberg, Germany
3 Fraunhofer IISB, Erlangen
abstract To simulate the bow of wafers with integrated capacitors in the form of pit arrays, various approaches were pursued. After unfruitful attempts to reliably obtain the wafer bow directly from simulating part of the wafer, a multi-scale approach was used. In this approach, the layer with the integrated capacitors was replaced by a homogeneous material having the same properties. Small-scale simulations of representative parts of the layer were performed to determine its effective stiffness tensor. Inclusion of the intrinsic strains of the grown and deposited dielectric and conductive layers enabled the volume change to be calculated of the layer with the integrated capacitors upon fabrication. Finally, the structure obtained was used in a full-wafer-scale model to simulate the bow of the wafers. Even for uncalibrated values for the coefficients of thermal expansion, most simulations agreed well with measurements. |
| 14:20 |
20mn |
Modelling Methodologies for Assessment of 3D Inkjet-Printed Electronics
Stoyan Stoyanov, Georgios Tourloukis, Tim Tilford , Chris Bailey, University of Greenwich
abstract 3D printing technologies provide one of the most efficient methods for product design, prototyping and manufacture in a cost-effective, high-throughput, mass-customisation and energy efficient manner. One growing application of 3D printing includes the fabrication, packaging and integration of electronic structures and components.This paper presents modelling methodologies and toolsets that can be used to address some of the present design-for-reliability challenges related to 3D inkjet-printed electronics. The use of advanced capabilities in finite element modelling is proposed and employed in order to predict the mechanical behaviour of cured ink-based materials when deposited sequentially layer-by-layer. Such build-up approach can lead to structural weakness and dimensional inaccuracy in the third dimension due to cure shrinkage. In addition, effects of different process and material parameters on the stress induced in silver ink printed conductive lines under thermal load are analysed. This analysis uses integrated finite element based design-of-simulations approach and response surface modelling. The geometric design of the investigated printed structure are found to be less influential compared with the mechanical properties of the cured insulating material and the magnitude of the temperature load to which the structure is exposed. |
| 14:40 |
20mn |
Mechanistic Model for the Unique Mechanical Behavior of Assemblies Bonded with Multilayered Pressure-Sensitive Adhesives
Hao Huang 1, Abhijit Dasgupta 1, Ehsan Mirbagheri 2
1 CALCE, University of MAryland, College Park, MD 20742, USA
2 Microsoft Coproration, Redmond, WA, 98052, USA
abstract The focus of this paper is on a modeling methodology for capturing the complex mechanical behavior of a single layer pressure-sensitive adhesive (PSA) system, based on empirical observations of its stress-strain behavior. This study is motivated by the fact that there is very limited modeling ability to mechanistically predict the bimodal stress-strain curves of single-layer PSAs. Empirical observations verify that this behavior is due to softening caused by nucleation and growth of cavities in the early deformation stage and hardening due to fibrillation during the final deformation stage before terminal debonding from the substrate. The effects of different loading conditions, including loading rate, stress and temperature, on PSA systems are also important. In-depth physics-based understanding of the connection between morphological changes in the joint and mechanical performance (including relevant failure mechanisms) of PSA-bonded assemblies will help to optimize PSA materials and joint architecture for maximum performance and durability. The goal of the mechanical modeling capability proposed in this study is to enable a virtual testing capability with reasonably high fidelity.The proposed modeling approach builds on an existing ‘block model’ methodology [1] and improves the existing approach by modeling each block with a strain-hardening viscoelastic constitutive model to capture the fibrillation process. Results show reasonable agreement between this improved mechanistic ‘block model’ and experiments. Such a mechanistic model can now be used as a virtual-testing tool, to explore how these PSA systems will behave on different substrates under different loading conditions. |
| 15:00 |
20mn |
To Predict Component Reliability for Active Safety Devices under Automotive Application
Nikhil Govindaiah, Robert Bosch Engineering and Business Solutions Pvt Limited(RBEI), Bangalore, India
Dr Marc Dressler, Robert Bosch GmbH, Schwieberdingen, Germany
abstract The new generation active safety control units has enhanced features like pedestrian detection, tunnel detection, night vision etc. These driver assistance functions support the driver by triggering warnings in critical driving situations. These devices mounted on the vehicles has to sustain these additional loads and harsh environmental conditions. Reliability of such devices are very critical to human safety, hence needs to be designed with a very critical development process. Various design iterations are to be evaluated and optimized with the help of advanced design practices and finite element analysis followed by rigorous measurement and testing. One of the most common and critical environment load comes from thermal loading which accounts for maximum number of failures of electronic devices in automotive application. Heat dissipation of components inside these devices during their operation in combination with environmental load leads to inhomogeneous temperature distribution and global deformation, and therefore loading on the solder joints. The damage of the Solder joints of an electronic device inside this device depends on the thermal expansion mismatch between the materials of the device and PCB (Printed Circuit Board), so called local mismatch. Critical components like the Ball Grid Arrays (BGA) are the worst susceptible to such solder joint failures. The PCB strains and temperature distributions under coupled thermal and thermo-mechanical loads have to be properly understood in order to prevent any component placement related failures. An effective way to reduce the development cycle time is to resolve the defects at the initial stages. With this objective a coupled thermal and thermo-mechanical simulation was carried out considering active temperature cycle loads on the device at system-level. As the thermomechanical fatigue of solder joints on the system level is more complex to predict than on the board level. We used a two-step submodel approach. In the first step the electronic device with BGA package was included in the global device, though the creep behavior of solder joints was omitted, by considering the populated PCB with all relevant components (i.e. capacitors, inductors, connector etc.) which influence the strain on the PCB during thermal loading conditions, it is observed that the tendency of strain over temperature is in very good agreement, leading to more realistic PCB strains to co-relate with the measurement data. In the second step the simulation of the solder joints fatigue was carried out with the help of the submodel. The submodel technique allowed to reduce the simulation model of a system to the electronic device model with a piece of the PCB underneath and at the same time maintain realistic PCB deformations and the realistic temperature field in the entire submodel during the temperature cycle. The warpage of the component in not soldered state was used to obtain the proper material properties as well as to account also for the form change (cry, smile) during thermal cycling. This shape change leads to additional loading on the solder balls. Additional, the warpage in the soldered state on free PCB and in the housing was measured and compared with simulation results. By combining FE simulation and measurements at the early stage of product development, it is possible to estimate the risk factor to meet the design specifications. |
| Session 16 |
Prognostics & Health Monitoring |
15:40 Theatrum Anatomicum |
Tuesday April 19 2016 |
| Chaired by Przemyslaw Gromala, Gamal Refai-Ahmed |
| 15:40 |
30mn |
Keynote presentation – Aerospace mission success and safety: PHM effort using Bayes formula BAZ model and beta-distribution
E. Suhir, Portland State University, Portland, OR, USA; ERS Co., USA
abstract When encountering a particular reliability problem at the design, fabrication, testing, or an operation stage of an electronics product’s life, and considering the use of predictive modeling to assess the seriousness and possible consequences of its detected malfunction and likely failure, one has to choose whether a statistical, or a physics-offailure-based, or a suitable combination of these two major predictive modeling tools should be employed to address the problem and to decide on how to proceed. An effective aerospace-electronics reliability-assurance (AERA) approach is suggested as a possible way to go in such a situation. In this approach the classical statistical Bayes formula (BF) is used at the first step as a technical diagnostics (TD) tool, with an objective to identify, on the probabilistic basis, the faulty (malfunctioning) device(s) from the obtained prognostics-and-health-monitoring (PHM) signals (“symptoms of faults”). The physics-offailure-based Boltzmann-Arrhenius-Zhurkov’s (BAZ) equation, a powerful, flexible and physically meaningful modeling tool suggested about five years ago can be employed at the second step with an objective is to assess the remaining useful life (RUL) of the malfunctioning device(s). If the predicted RUL is still long enough, no action might be needed, but if not, a corrective (restoration) action becomes necessary. It is shown in this connection how short/long the repair time should/could be, so that the availability of the equipment (the probability that it is sound and available to the user when needed) does not fall below the allowable level. In any event, after the first two steps of the AERA modeling effort are carried out, and the assessed probability of the product’s continuing operation is found to be satisfactory, the device is put back into operation (testing). If failure nonetheless occurs, the third AERA step should be undertaken to update reliability. A well-known four-parametric statistical beta-distribution (BD), in which the probability of failure is treated as a random variable, can be used at this step. The general AERA concept is illustrated by a detailed numerical example geared to an en-route flight mission. The approach can be used, however, also beyond the aerospace field in other vehicular technologies: maritime, automotive, railroad, etc. |
| 16:10 |
20mn |
Failure Analysis of Virtual and Physical Machines: Patterns, Causes and Characteristics
Andrew McPherson, IBM Research, Zürich, Switzerland |
| 16:30 |
20mn |
Towards Prognostics and Health Monitoring: The Potential of Fault Detection by Piezoresistive Silicon Stress Sensor
Alicja Palczynska 1, Alexandru Prisacaru 1, Przemyslaw Jakub Gromala 1, Bongtae Han 2, Dirk Mayer 3, Tobias Melz 3
1 Robert Bosch GmbH, Reliability Modeling and System Optimization (AE/EDT3), Reutlingen, 72703, Germany
2 Mechanical Engineering Department, University of Maryland College Park, MD 20742, USA
3 Fraunhofer-Institut für Betriebsfestigkeit und Systemzuverlässigkeit LBF, Darmstadt, 64289, Germany
abstract A piezoresistive silicon based stress sensor has been demonstrated successfully as an effective tool to monitor the stresses inside electronic packages during various production processes. More recently, the sensor has been evaluated as a sensor for Prognostics and Health Monitoring (PHM) systems. This paper presents a systematic approach that evaluates its performance from the perspective of failure mode detection. A detailed Finite Element method (FEM) model of existing test vehicles is created. The test vehicle consists of six DPAK power packages and three stress sensors. The results of simulation are verified by the signals obtained from the stress sensor as well as the supplementary warpage measurements. After inserting various failure modes into the model, statistical pattern recognition algorithms are implemented for fault detection and classification. The proposed technique can identify detectable failures during reliability testing by utilizing the database of stress sensor responses for healthy and unhealthy state. Thus, the results establish a baseline for the applicability of the piezoresistive stress sensor for an on-line monitoring PHM methodology. |
| 16:50 |
20mn |
Reliability Analysis of Solder Joints under Different Thermal and Thermo-mechanical Loading Conditions: Case Study of Automotive ECUs
Abdalla Youssef 1, Ingo Birner 1, Holger Voelkel 1, Jean Thierauf 1, Robert Vodiunig 1, Andreas Middendorf 2, Klaus-Dieter Lang 2
1 BMW Group, Munich, Germany
2 Technische Universität Berlin, Forschungsschwerpunkt Technologien der Mikroperipherik, Berlin, Germany |
| Session 20 |
Solder joint fatigue characterisation and simulation |
11:00 Salle des Actes |
Wednesday April 20 2016 |
| Chaired by Rainer Dudek, Volker Hildenbrand |
| 11:00 |
30mn |
Keynote presentation – The Role of Stress State and Stress Triaxiality in Lifetime Prediction of Solder Joints in Different Packages Utilized in Automotive Electronics
M. Kuczyńska 1, N. Schafet 2, U. Becker 2, B. Métais 3, A. Kabakchiev 4, P. Buhl 5, S. Weihe 5
1 Robert Bosch GmbH, Automotive Electronics Division; Materials Testing Institute (MPA) University of Stuttgart
2 Robert Bosch GmbH, Automotive Electronics Division
3 Robert Bosch GmbH, Corporate Research Division; Materials Testing Institute (MPA) University of Stuttgart
4 Robert Bosch GmbH, Corporate Research Division
5 Materials Testing Institute (MPA) University of Stuttgart
abstract This work presents an overview on the role of the stress state and stress Triaxiality Factor in lifetime prediction of solder connections. Two package types, the Loss Free Packaging (LFPAK) and the Plastic Ball Grid Array (PBGA), were investigated by means of FE-simulation on Board- and System-Level, and presented damage prediction will be compared with experimental data. In the LFPAK and BGA solder joints the regimes of hydrostatic tension and compression during temperature cycles are evaluated and compared with distribution of equivalent von Mises stress, stress intensity (maximum shear stress) and triaxiality.The increments of damage related variables, inelastic strain and energy density, were modified in a post-processing routine according to the current state of hydrostatic stress and TF for each time increment.Further, using a simplified simulation approach, the path of the crack propagation was calculated according to the distribution of the modified and non-modified inelastic strain. It is shown that when including multiaxial effects by modification of damage related variables a better correlation between calculated and experimentally observed crack path is achieved. |
| 11:30 |
20mn |
Sub-Micrometer Warpage Measurement Setups for the Verification of Material Models of Soft Solder Die Attaches by Inverse Modeling
Martin Niessner 1, Rainer Dudek 2, Marcus Hildebrandt 2, Matthias Gehring 3, Yang Yongbo 4, Andreas Piller 1, Gabriele Schrag 3
1 Infineon Technologies AG, Neubiberg, Germany
2 Fraunhofer ENAS, Micro Materials Center, Chemnitz, Germany
3 Institute for Physics of Electrotechnology, Technical University of Munich, Munich, Germany
4 Infineon Technologies AG, Singapore, Singapore
abstract In contrast to the use of lead free solders in most electronic applications, replacement of high-lead materials has not yet been possible for die attach in power electronics. Accordingly, there is still some need for creep data input in related simulations. Several creep models of high-lead soft solder die attach materials were published, which were extracted from macro-scale material samples. However, as it is generally known for soft solders, their creep behavior depends strongly on microstructure and a creep description close to the application is to be preferred. In order to assess the validity of the creep models at micro-scale in a use-scenario, this work uses two recently developed experimental setups with sub-µm warpage measurement capability. The warpage of three-layered samples is measured over temperature and simulated using four different published creep models. The solder models are able to reproduce the measured change in warpage direction with certain accuracy, but also show deviations from the measured behavior of the test samples which requires further investigation. |
| 11:50 |
20mn |
Fatigue crack growth modeling in the metallization of power semiconductors under active cycling conditions
Martin Springer 1, Michael Nelhiebel 2, Heinz Pettermann 1
1 Institute of Lightweight Design and Structural Biomechanics, Vienna, Austria
2 Infineon Technologies Austria AG, Villach, Austria
abstract Power semiconductors may be subjected to short electric overload pulses during operation, which induce very high temperatures and temperature gradients in the multilayer chip structure. This may lead to damage in the ductile metallization and repetitive overload conditions would result in damage propagation and overheating of the device. Hence, an elasto–plastic fatigue model is developed to predict material failure in the metallization of power electronic devices caused by thermo–mechanical loading. |
| 12:10 |
20mn |
Experimental and numerical investigation of fatigue damage development under multiaxial loads in a lead-free Sn-based solder alloy
Benjamin Métais 1, Marta Kuczynska 2, Alexander Kabakchiev 3, Simon Wolfangel 4, Patrick Buhl 5, Stefan Weihe 5
1 Corporate Research Div. Robert Bosch GmbH, MPA University of Stuttgart
2 Automotive Electronic Div. Robert Bosch GmbH, MPA University of Stuttgart
3 Corporate Research Div. Robert Bosch GmbH
4 Automotive Electronic Div. Robert Bosch GmbH
5 MPA University of Stuttgart
abstract Electronic devices for automotive applications undergo substantial thermo-mechanical cyclic loads during their operation. Within the phase of assembly, a large variety of passive and active electronic components are electrically connected by solder joints of complex geometrical shapes. As a consequence, external thermomechanical loads result in local multiaxial stress states in the solder material during their operation. In the past years, significant efforts were made in the characterization of solder materials and the accurate FE-modeling of their viscoplastic deformation behavior as well as the modeling of their damage behavior. However, material testing and numerical model calibration were focused on uniaxial tests, which result in a homogeneous stress state and a fixed ratio between its hydrostatic and deviatoric parts. Therefore, the correlation between varying multiaxial loads and cyclic damage evolution in solder alloys is still not understood. Here, we report on the experimental investigation of Low Cycle Fatigue (LCF) on bulk samples under uniaxial and multiaxial stress states realized by means of a pure tension-compression and superimposed tension-torsion loads. In order to describe the observed cyclic degradation behavior, a phenomenological fatigue damage model is modified incorporating the influence of multiaxial stresses in the damage development. The new damage model is implemented as a user-subroutine for Finite Element (FE) calculation supported by the commercial FE-package AnsysTM. Uniaxial and multiaxial loads are simulated on the meshed specimen-geometry. The material model is able to describe the mechanical properties in the initial state of deformation. Besides, it shows numerical stability which enables the simulation of large number of cyclic loads. Based on the damage mechanic approach enhanced by multiaxial effects, this study contributes to the framework of solder joints modeling |
| 12:30 |
20mn |
Advances and Challenges of Experimental Reliability Investigations for Lifetime Modelling of Sintered Silver based Interconnections
J. Heilmann 1, I. Nikitin 2, U. Zschenderlein 1, D. May 1, K. Pressel 2, B. Wunderle 3
1 Technische Universität Chemnitz, Lehrstuhl Werkstoffe und Zuverlässigkeit mikrotechnischer Systeme, Chemnitz, Germany
2 Infineon Technologies, Regensburg, Germany
3 Technische Universität Chemnitz, Germany; Fraunhofer Institut für Elektronische Nanosysteme ENAS, Chemnitz, Germany
abstract The cost and the package size driven size reduction of semiconductors lead to much higher heat generation. Also the use of new high power technologies on the basis of SiC produces is a need for high conductivity of the interconnect materials. Therefore the requirements for mechanical, thermal and electrical properties of interconnect materials increase compared to existing eutectic solder and glue materials. One of the promising solutions is a sintered layer between semiconductor and substrate. Especially from sintered layers one expects very high thermal conductivity and good mechanical properties in the package. Therefore, new materials with advanced behavior exploiting nano-effects have been developed in the last years. However, processes to use such materials as TIM-material for power applications are still to be optimized for e.g. zero pressure processing. So also their failure mechanisms, to be identified in lifetime investigations, are yet unknown as well as their stability. In order to enable prolonged function of these interfaces, thermo-mechanical reliability has to be assured. Dedicated fatigue tests have to be conducted to evaluate lifetime under relevant testing conditions, then failure mechanisms such as delamination or cracking have to be identified, understood and quantitatively condensed into a lifetime model to predict reliability for future designs. Within this paper, we present a guideline for the mechanical acceleration of reliability experiments for end-of-lifetime prognostics as well as the state of the art regarding reliability and mechanical characterization of sintered silver. |
