Correlation study on moisture soak equivalent between MSL1 (85/85% soaking 168 hours) and Autoclave test in term of weight gain and delamination

Abstract

Delamination is very critical for Power Mosfet devices especially Die Attach (DA) delamination. This is due to drain is always connected to Die Attach Paddle (DAP) area using interconnect (soft solder or epoxy type). When there is DA delamination occuring, resistance between Drain and Source will increase causing slow switching time on Power Mosfet devices. Since delamination is very crucial for Power Mosfet, a lot of design of engineerings (DOEs) are performed using on Moisture Sensitivity Level 1 (MSL 1) to screen the delamination. However MSL 1 always takes considerable long duration (168hrs) to complete the study. Time to market release of the products will be further delayed when repeat DOE is needed. This paper will discuss correlation study between Autoclave test (ACLV) and MSL 1 in term of delamination and weight gain (moisture absorption) of mold compound been done. Three mold compounds have been selected to perform weight gain study and delamination check to correlate MSL 1 versus ACLV test. Results on correlation between MSL 1 (85/85% soaking 168 hours) versus ACLV found DOE study can be used in evaluation stage to reduce DOE duration as it is comparable.