04030535 INSPEC Abstract Number: B9201-0170J-005

Title: Thermal fatigue failures of large scale package type power transistor modules

Author(s): Sumi, S.; Ohga, K.; Shirai, K.

Author Affiliation: Fuji Electr. Co. Ltd., Nagano, Japan

Conference Title: ISTFA International Symposium for Testing and Failure Analysis. The Failure Analysis Forum for Microelectronics and Advanced Materials. Conference Proceedings p.309-22

Publisher: ASM Int, Materials Park, OH, USA

Publication Date: 1989 Country of Publication: USA xii+575 pp.

ISBN: 0 87170 368 8

Conference Sponsor: Seal Lab

Conference Date: 6-10 Nov. 1989 Conference Location: Los Angeles, CA, USA

Language: English Document Type: Conference Paper (PA)

Treatment: Practical (P)

Abstract: When large scale package type power transistor modules are subjected to severe temperature cyclings, they can fail by thermal fatigue due to thermal stress caused by different thermal expansion coefficients of package materials. Representative failure modes found in thermal cycling operations were as follows; die mounting solder joints thermal fatigues, caused by intermittent load operations with relatively short time intervals and increased thermal resistances; bonding wire breaks near wire to chip interfaces caused mainly by high temperature changes of inner lead wires and chip metallizations; solder joint breaks in leads to external terminals caused by thermal expansion coefficients differences between copper leads and plastic housings. The authors analyzed these failure mechanisms by use of failure analysis techniques such as infrared thermal imagings and SEM observations, and developed effective evaluation methods for thermal cycling life. (0 Refs)

Descriptors: failure analysis; infrared imaging; integrated circuit testing; modules; packaging; power integrated circuits; power transistors; scanning electron microscopy; thermal stress cracking

Identifiers: large scale package type power transistor modules; severe temperature cyclings; thermal fatigue; thermal stress; thermal expansion coefficients; package materials; die mounting solder joints thermal fatigues; bonding wire breaks; wire to chip interfaces; inner lead wires; chip metallizations; solder joint breaks; failure analysis techniques; infrared thermal imagings; SEM

Class Codes: B0170J (Product packaging); B0170N (Reliability); B2570 ( Semiconductor integrated circuits)