Development of SiC Chip Based Power Package for High Power and High Performance Application

In this paper, a SiC device based power package with double side cooling capability is designed and developed for high power, high performance application. The developed power package mainly consists of high power rated SiC chips, customized metal clips forming the electrical interconnections, and active metal brazing (AMB) substrates with specially designed cavities. the customized interconnects and the use of paralleled high-power SiC devices in the developed package enable its usage for high power applications. High temperature sustainability is obtained by utilizing the high temperature endurable materials for the interconnections and encapsulation. High thermal performance is realized by shortening the heat transfer path from the SiC chips to liquid cooling heat sink and implementing the double side liquid cooling scheme. In addition, by embedding the chip inside the AMB substrate and replacing the wire-bond interconnections with the flatted copper clip interconnections, the developed power package is with low profile. Significant improvement (> 50%) of the thermal performance has been achieved for the developed power package as compared with the thermal performance of the conventional wire bonded power package. Very low loop inductance along the electric current flow path has been obtained (i.e., 2.7nH at 1Mhz of frequency). High temperature endurable package materials (e.g., die attach and encapsulation material) have been evaluated. The developed power package has been fabricated and passed the specified reliability assessments, i.e., unbiased Highly Accelerated Stress Test (HAST), temperature cycling (TC) test (-40~200 °C), High temperature storage (HTS) test at 250 °C and power cycling (PC) test (ΔT= 150 °C).