State-Of-The-Art Approach to Mitigate Risk of Die Crack with Substrate Co-Planarity Issue

Miniaturization and compact IC package are the main driver for Die Attach Film (DAF) implementation. DAF as alternative to liquid epoxy to overcome problems such as epoxy bleed, uneven bond line thickness (BLT). However, one of the challenges in DAF processing is presence of delamination/ void. This work outlines the correlation between substrate topography with DAF void and die crack. The die crack with fixed location and pattern is caused by void between Die Attach Film (DAF) and substrate. DAF-Substrate separation occurs at the lower side of uneven flatness of DAP which is a "Pivot effect" underneath the die when high packing pressure in mold process and shrinkage during cross linking of mold compound. This eventually leads to die crack. Voids formation can be reduced by optimizing die attach parameter. Based on the DOE conducted, high bond delay and high bond temperature significantly improved on the voids and die crack. These findings provide insights into improving the reliability of IC packaging and optimizing the DAF process for future applications.