Modeling and Analysis of Silver-Sintered Molybdenum Packaging for SiC Power Modules With Improved Lifetime and Temperature Range

Abstract

With the application of wide bandgap devices, the packaging technology of power modules is faced with elevated challenges. This paper proposes a new packaging concept for silicon carbide power modules. The main objective is to improve the lifetime and temperature range, while the proposed packaging also has the potential to reduce stray inductance and simplify the fabrication process. In the proposed concept, sintered nano-silver is selected as the die bonding. The conventional direct-bonded-copper substrate is replaced by a molybdenum layer and a bismaleimide triazine resin layer which has a low thermal expansion coefficient. A steady-state thermal-mechanical analysis is conducted to verify the material selection. Furthermore, a transient thermal-mechanical analysis based on JEDEC temperature cycling methods is carried out, whose results are applied in the Coffin-Manson lifetime model to evaluate the advantages of the proposed Silver-Sintered Molybdenum Packaging. The results demonstrated that the proposed packaging technology could improve the lifetime by over 1000 times and increase the maximum operating temperature by nearly 3 times. Finally, a feasible process of sintering SiC chips on molybdenum substrates is proposed, which achieves a uniform and low porosity bonding.