Investigation on Copper Clip Bonding Structure for Power Package

In this paper, the influence of copper clip package on thermal stress of power devices is studied. The effects of die thickness, clip thickness, solder thickness and PCB thickness on the thermal stress were analyzed by finite element model. Response surface methodology and design of experiment (DoE) are exploited to optimize package design and obtain an analytical formula of thermal stress of the solder layer which is the weakest part of the package. Based on the analysis, a copper clip package design with slot design is proposed to reduce the thermal stress. The experimental results show that the slot structure contribute to the release of the planar circumferential stress, and the thermal stress of the solder layer is reduced.