The Effect of EMC Material Properties on Large Area Silver Sintering Process in Power Module

EasyChair Preprint 13438

Abstract

With the development of transfer-molded power module devices in electric vehicle field, a large area silver sintering process has become one of the feasible solutions for connecting substrate to heat sink, due to the high thermal conductivity and reliability it can offer. However, silver sintering needs to be carried out under specific temperature and pressure conditions. During the sintering process, thermal stress can occur inside the power module due to the thermal mismatch between the epoxy molding compound (EMC) and the Si3N4 ceramic substrate, resulting in module warpage with a crying or smiling face. Severe warpage often leads to a high failure rate in large-area silver sintering. However, this problem can be mitigated by selecting an appropriate EMC material. Additionally, the mechanical behavior of EMC materials is closely related to temperature, which can also affect the failure rate of the silver sintering process. Although the impact of EMC material properties on the silver sintering process is very significant, there are few relevant studies on it. In this paper, the failure mechanism of the module in the sintering process is analyzed by the finite element simulation method (FEM). At the same time, simulation model is used to explore the effects of EMC's material parameters such as thermal expansion coefficient (CTE), glass transition temperature (Tg), and modulus on power module warpage and ceramic substrate stress. The simulation results offer crucial guidance for the selection of EMC and the setting of process parameters in silver sintering.

Keyphrases: EMC, power module, silver sintering, simulation, substrate failure

@booklet{EasyChair:13438,
  author    = {Chenglong Li and Liang Yao and Zongdai Liu and Lijun Song and Daohui Li},
  title     = {The Effect of EMC Material Properties on Large Area Silver Sintering Process in Power Module},
  howpublished = {EasyChair Preprint 13438},
  year      = {EasyChair, 2024}}