Effect of Lotus Cu on thermal shock properties in Ag-Sintered Joints

초록

This study examines the effect of unidirectional porous copper (Lotus Cu) on the thermal shock properties of Ag-sintered interfaces for Si/Cu bonding. In high-performance wide-bandgap semiconductor power modules, the large coefficient of thermal expansion (CTE) mismatch generates significant thermomechanical stresses, leading to interfacial degradation. Lotus Cu, with high vertical thermal conductivity and a low elastic modulus, was introduced as an alternative joining material. Si/Ag/Lotus Cu and Si/Ag/bulk Cu joints were fabricated via Ag sintering and evaluated through thermal cycling tests (?55 °C to 150 °C). After 500 cycles, bulk Cu joints exhibited extensive delamination, whereas Lotus Cu joints maintained partial bonding with only localized interfacial damage. These results suggest that the unique pore structure of Lotus Cu can redistribute thermal stress, provide more complex crack propagation paths, and potentially improve the reliability.