Accelerated thermal cycling and failure mechanisms for BGA and CSP assemblies

This paper reviews the accelerated thermal cycling test methods that are currently used by industry to characterize the interconnect reliability of commercial-off-the-shelf (COTS) ball grid array (BGA) and chip scale package (CSP) assemblies. Acceleration induced failure mechanisms varied from conventional surface mount (SM) failures for CSPs. Examples of unrealistic life projections for other CSPs are also presented. The cumulative cycles-to-failure for ceramic BGA assemblies performed under different conditions, including plots of their two Weibull parameters, are presented. The results are for cycles in the range of -30 degreesC to 100 degreesC, -55 degreesC to 100 degreesC, and -55 degreesC to 125 degreesC. Failure mechanisms, as well as cycles to failure for thermal shock and thermal cycling conditions in the range of -55 degreesC to 125 degreesC, were compared. Projection to other temperature cycling ranges using a modified Coffin-Manson relationship is also presented.