Inter-connecting process investigation to resolve delamination

Abstract

Delamination on the interface between mold compound to die, die paddle and inner leads study has been on-going for quite some time. This is a chronicle defect which will result in electrical continuity failure if delamination penetrates into the interface of mold compound to die surface and mold compound to inner leads e.g., delamination on inner leads or die surface to cause wire broken after thermal stress. To resolve delamination, better materials are needed such as Lead frame, die attach and mold compound. Other than that, a process optimization is also a must to achieve delamination free result. The paper portrays the phenomenon of how delamination occurred after improving the BOM e.g., less water absorption and higher adhesion mold compound. During qualification stage, no delamination occurred after thermal stress. But, on mass volume production run, the delamination occurs on inner leads by sampling check. Four “M” Men, Material, Method and Machines are thoroughly checked and compared with its qualification built and mass production run. No difference or conclusion can be observed and made. But, the delamination was there though no finding/difference was observed. However, one conclusion can be made is qualification is small volume but mass confirmation run is large volume. Based on the assumption, Delamination comparison between small volume VS. large volume was conducted to check the difference. Then, the root cause as die attach outgassing to cause contamination on package is observed. The contamination is later turn into delamination after Thermal.