Pressure Copper Sintering Paste for High-Power Device Die-Attach Applications

Abstract

Pressure copper (Cu) sintering paste with high shear strength, high thermal/electrical conductivity, and positive reliability was developed for high-power device die-attach applications. The paste is suitable for different metallizations, e.g., Au, Ag, and Cu. When sintering with 15-20MPa pressure, > 60MPa shear strength was achieved for 3mm x 3mm joints and> 30MPa for 5mm x 5mm joints. After more than 1000 hours (250°C) aging and 3500 cycles TCT (−40°C-17 SOC), the joints exhibited excellent performance without delamination. Shear strength increased with increased TCT cycles. This Cu sintering paste can be used for both dispensing and printing applications. For strong bonding between die and substrate, the sintering process requires N2, H2, formic acid, and a vacuum atmosphere.