Impact of manufacturing variation on the reliability/quality of an Opto-BGA system in package

This paper investigates the manufacturing variation in an Opto-BGA system in package (SIP) and its impact to the reliability and quality. Both the 3D finite element analysis (FEA) modeling and the reliability TMCL test on the opto-BGA manufacturing variation are studied. In the FEA model, the hyper-elastic behavior of the opto-coupling material is considered. In the reliability test, the samples are made in two groups, one is the typical case and the other is the worst case manufacturing variation in which the bond wire loop goes beyond the opto-coupling dome into the outer glob top coat layer. The modeling results show that in the typical design case, the die stress is too small to damage the opto-BGA. The peel stress in die attach is also very small. While in the worst case, the die stress is ten times greater than the typical case. The peel stress in die attach is much higher than the typical case when temperature increase to 125 C. From the result of TMCL reliability test, actual test data is found to correlate in failure location and mechanism with the modeling/simulation, for both typical and worst case manufacturing variation.