Temperature Cycling Performance of Bi-doped Solder Ball Alloy on DRAM Module Form and Daisy-Chained Printed Circuit Board

In this study, DRAM module and daisy-chained printed circuit board (DC-PCB) are selected as test vehicles to understand the effect of PCB form factors associated with Bi-doped solder ball alloys under different temperature cycling (TC) conditions. TC-J (0 to 100°C) and TC-G (-40 to 125°C) condition are conducted to DRAM module and DC-PCB, respectively. The results of Weibull analysis showed that Sn-4.0Ag-0.5Cu-0.05Ni-3.0Bi and Sn-2.0Ag-0.8Cu-0.05Ni-4.0Bi attached on organic solderability preservatives (OSP) substrate surface finishes have respectively enhanced 40% and 26% temperature cycling life compared to SAC302 mounted on electrolytic NiAu substrate surface finishes. The positive results demonstrated the feasibility of Bi-doped alloys to different products which require to survive in harsher environment.