Title :
Influence of under-bump metallurgy and solder alloys on the crack in the wafer level chip scale packaging
Author :
Lu, Julia Hsin-Lin ; Xu, Mengdi ; Zhang, Haijun ; Lu, H.L. ; Zhang, David Wei
Author_Institution :
Dept. of Opt. Sci. & Eng., Fudan Univ., Shanghai, China
Abstract :
The finite element method (FEM) is employed to investigate the solder crack mechanism in wafer level chip scale packaging (WLCSP). The location of the initial crack is calculated and is compared to the experimental one. Moreover, the impact of the following three aspects, e.g. under-bump metallurgy (UBM) materials, solder alloy, and the thickness of the UBM layers on the initial crack growth in solder is investigated by calculating J-integral, respectively, which reflects the possibility of crack growth. It is concluded that the J-integral values in 96.5Sn3.5Ag solder and the Au-Ni-Cu-Ti UBM material are smaller than other cases.
Keywords :
copper alloys; cracks; finite element analysis; gold alloys; nickel alloys; silver alloys; soldering; tin alloys; titanium alloys; wafer level packaging; Au-Ni-Cu-Ti; J-integral; Sn-Ag; UBM material; crack growth; finite element method; solder alloy; solder crack mechanism; under bump metallurgy; wafer level chip scale packaging; Finite element analysis; Gold; Materials; Nickel; Strain; Stress; Crack growth; FEM; UBM; WLCSP;
Conference_Titel :
Electron Devices and Solid State Circuit (EDSSC), 2012 IEEE International Conference on
Conference_Location :
Bangkok
Print_ISBN :
978-1-4673-5694-7
DOI :
10.1109/EDSSC.2012.6482769
