Localized Recrystallization and Cracking Behavior of Lead-free Solder Interconnections under Thermal Cycling
The failure mechanism of lead-free solder interconnections under thermal cycling has been studied by cross-polarized light microscopy, scanning electronic microscopy (SEM), and nanoindentation test. From the results of finite element modeling (FEM), it was found that the critical solder interconnection was located at the chip corner, and the stress was concentrated at the outer neck region beneath the ball grid arrays (BGA) component. The FEM results were in good agreement with the experimental observation. Two failure modes of the interconnections were identified: one is the intergranular or transgranular cracking through many small equiaxed recrystallized grains and the other is the transgranular cracking in few large irregularly shaped recrystallized grains. The results show that the localized recrystallization makes the Ag3Sn intermetallic compounds (IMC) coalesce and distribute sparsely, which leads to the degradation of the recrystallized microstructure and easy propagation of the cracks.
H. T. Chen T. Mattila J. Li X. W. Liu M. Y. Li J. K. Kivilahti
Shenzhen Graduate School, Harbin Institute of Technology, Shenzhen, 518055, China Laboratory of Electronics Production Technology, Helsinki University of Technology, P. O. Box 3000, Laboratory of materials science, Helsinki University of Technology, P.O. Box 6200, 02015, Finland
国际会议
北京
英文
562-568
2009-08-10（万方平台首次上网日期，不代表论文的发表时间）