Highly reliable micro-scale Cu sintered joint by oxidation-reduction bonding process under thermal cycling

Thermal cycling reliability of micro-scale Cu sintered joint by oxidation-reduction bonding (ORB) process for power module die attach was investigated. A robust bonding strength of Cu ORB joint over 40 MPa with the bonding temperature of 300 °C and applied pressure of 0.5 MPa was successfully achieved. After thermal cycling, there is no evidence of significant crack propagation or delamination at the Cu sintered layer, resulting in no shear strength degradation up to 1000 cycles. The highly reliable Cu sintered joint by ORB can be achieved, as a result, Cu ORB process can be promising technique for power module die attach process.