Oxidation-Free Sintered Copper Die Attachment for Power Electronics Packaging

The rapid development of wide-bandgap semiconductors imposed stringent requirements for die attachment for power electronic packaging. Among which, sintered copper is becoming an advanced die attachment technology, since it offers much higher melting point, thermal conductivity, and reliability than traditional solders; lower cost and better resistance to electrochemical migration than sintered silver. However, the inherent property of copper oxidation during sintering in the air is an obstacle to applications. In this study, an antioxidative copper paste was developed by encapsulating 600 nm submicron copper particles with reducing solvents. The SEM and EDS results verified oxidation-free and delamination-free Cu-Cu joints. The effects of sintering temperature, pressure, and time were investigated in detail. Die-Shear strength of 48.1 MPa, electrical resistivity of 5.19×10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-7</sup> Ω·m, and thermal conductivity of 209.36 W/m·K were obtained, indicating excellent mechanical, electrical, and thermal properties. This study provides a more economical and advanced packaging technology for power electronics packaging.