Reliability analysis of large area sintered Cu interconnects based on simulation and thermal shock test
Jiaqi Gao, Yang Liu, Yue Gao, Zhang JingPurpose
The purpose of this study is to assess the thermomechanical reliability of large-area sintered Cu interconnects for automotive power modules under actual operating conditions and to determine the optimal sintering layer thickness using finite element simulation and experimental validation. The escalating demand for high-performance electronic packaging has underscored the significance of sintered Cu interconnects, renowned for their superior electrical and thermal conductivities. Recent attempts to apply large-area sintered Cu between the module and heatsink have shown that such interconnections can achieve lower thermal resistance and higher bonding strength. However, the reliability of these interconnects under thermal cycling conditions remains a critical concern.
Design/methodology/approach
This study used a combined approach of finite element (FE) simulation and experimental validation to assess the reliability of sintered Cu interconnects under actual operating conditions. First, FE simulation is conducted under irregular thermal flux to simulate the actual working conditions of the module. Based on the stress–strain results, the optimal sintering layer thickness is determined, while also considering printing yield and economic feasibility. Subsequently, shear strength tests were conducted on shear specimen model and thermal shock testing (TST) along with C SAM (scanning acoustic microscopy) analysis were performed on TST specimen.
Findings
This study evaluates the thermomechanical reliability of large-area sintered copper interconnects for automotive power modules. Combining FE simulations and experiments, the optimal sintering layer thickness was determined to be 100 µm. The overall structure exhibited high shear strength (>25 MPa) and withstood 1,000 thermal shock cycles (−40 °C to 125 °C) with a delamination rate of only 1.575% and negligible crack propagation. Its excellent reliability for next-generation electronics was confirmed.
Originality/value
This study provides the reliability assessment of large-area sintered Cu interconnects specifically for automotive power modules, bridging the gap between process optimization and durability in actual working conditions. The identified optimal thickness of 100 µm sintered layer offers a critical design rule, balancing thermomechanical performance with manufacturability. The combined simulation-experimental approach quantitatively validates that this interconnect solution can withstand stringent automotive thermal cycling with exceptional durability (<2% delamination after 1,000 cycles), offering a credible high-performance alternative to traditional solders or sintered silver.