Effect of cracks on thermal stress and strain of a tape automated bonded package

摘要

A tape automated bonded (TAB) package is basically a composite structure. A three-dimensional finite element fracture analysis was performed to evaluate the effects of cracks in a TAB package under thermal cycling conditions. The lead-tin solder in the outer lead bond as well as the copper beam lead were taken as elasto-plastic materials. Interface cracks between the copper beam lead and the solder were included in the analysis. It was found that the prescribed cracks created new sources of stress concentrations, which are fairly mild. This result showed that the configuration of the outer lead bonds in TAB packages is generally resilient to thermal cycling, even with the presence of defects such as cracks.