Solder Joint Reliability of Double sided Assembled PLP Package

Generally packages assembled on printed circuit boards (PCBs) in a back to back double sided configuration. A critical issue of double sided assemblies was board level thermal cycling reliability. This paper studied the reliability issues for package to board attachment. Daisy-chained PLP packages mounted on 1.0mm thick PCB by LF35 (SAC125Ni) solder. These included single sided assembly and double sided assembly configurations. Accelerated temperature cycling tests were carried out to investigate the effect of double-sided PKG assembly on the solder joint reliability. The cumulative cycles to failure for PLP assemblies performed under different conditions, including plots of their two Weibull parameters, are presented. The results are for cycles in the range of -40°C to 85°C, -40°C to 125°C, and -55°C to 125°C. Projection data of 3 kinds of temperature cycle ranges were calculated using a modified Coffin-Manson relationship. Consequently, our experiment showed that the great reduction in solder joint reliability of mirror double sided assembly as compared to a single-side assembly.