Development of a Novel Lead Frame Based Double Side Liquid Cooling High Performance SiC Power Module

Abstract

In this study, a novel Cu lead frame (LF) based double side cooling SiC power module is proposed and developed. The proposed SiC power module eliminates the conventional direct bonded copper (DBC) substrates by implementing a dedicated copper lead frame. Meanwhile, the proposed power module is capable for double side liquid cooling scheme by employing the flat copper clips at the top side of SiC devices. Furthermore, the high temperature endurable materials, i.e. epoxy molding compound (EMC), die attachment (DA) and lead free solder, are evaluated and identified for the proposed power module. In addition, the processes for interconnects (i.e. die attach and solder joints) formation and package encapsulation is optimized for the power module assembly. Lastly, the adhesive dielectric thermal interface material (TIM) with high thermal conductivity is recommended to bond the power module with the heat sink. The proposed power module has been fabricated with identified materials and gone through the specified reliability assessments, e.g. unbiased highly accelerated stress test (uHAST), temperature cycling (TC) test (−40∼150°C) for 1,000 cycles, high temperature storage (HTS) test at 200°C for 1,000hrs and power cycling test (PCT) ($\Delta \mathrm{T}=150^{\circ}\mathrm{C}$) for 50,000 cycles. Failure analysis has been conducted for the failed samples.