- 著者
- Hiroki Kanai Yoshiharu Kariya Hiroshige Sugimoto Yoshiki Abe Yoshinori Yokoyama Koki Ochi Ryuichiro Hanada Shinnosuke Soda
- 出版者
- The Japan Institute of Metals and Materials
- 雑誌
- MATERIALS TRANSACTIONS (ISSN:13459678)
- 巻号頁・発行日
- vol.63, no.6, pp.759-765, 2022-06-01 (Released:2022-05-25)
- 参考文献数
- 12
- 被引用文献数
- 2
A method for predicting the lifetime of fatigue crack network formation in die-attach joints is considered through experiments on high-speed thermal cycling using a Si/solder/Si joint specimen and the mechanism is identified. Equibiaxial stresses are generated in the solder layer because thermal deformation of the solder is constrained by the Si, which causes continuous initiation and propagation of crisscross-shaped cracks. When the crack density is sufficiently high, crack growth is arrested by collisions between cracks, and the formation of the fatigue crack network is completed. Based on these results, development of the damaged area and arrest of the development by collisions between the cracks is expressed in terms of extended volume theory incorporating crack initiation and propagation functions for solder as well as considering the damage rate equation. The experimental result for the relationship between the damage ratio in the die-attach joint and the number of cycles under each thermal condition are reproduced by the damage rate equation.
- 著者
- Masaki Moriuchi Yoshiharu Kariya Mao Kondo Yoshihiko Kanda
- 出版者
- The Japan Institute of Metals and Materials
- 雑誌
- MATERIALS TRANSACTIONS (ISSN:13459678)
- 巻号頁・発行日
- vol.63, no.6, pp.805-812, 2022-06-01 (Released:2022-05-25)
- 参考文献数
- 29
- 被引用文献数
- 7
The creep deformation mechanism of Sn–Ag–Cu alloy doped with Bi and Sb (SACBiSb) alloys is theoretically and experimentally analyzed in order to clarify the effect of solid solution additives in Sn–Ag–Cu alloys. The theoretical prediction results and test results are found to mostly agree with each other. The breakaway stress which is the stress at the transition from Class II to Class I in particular is finely reproduced in the theoretical prediction, with a stress of 25 MPa found both by the prediction and test results. In the stress range where the stress is higher than the breakaway stress, the creep strength of SACBiSb is higher than that of Sn–Ag–Cu, while it was predicted that the creep strength of Sn–Ag–Cu would be superior to that of SACBiSb in the range of stress lower than the breakaway stress. The thermal fatigue life of SACBiSb was predicted to be longer than that of Sn–Ag–Cu in the temperature profile mainly used above the breakaway stress. However, in the temperature profile mainly used in the low-stress range, a reversal of the creep strength between SACBiSb and Sn–Ag–Cu was predicted to occur and the loss of the superiority of SACBiSb in the thermal fatigue life was also predicted.