Preparation of Strong-Adhesion and High-Conductivity Copper Films on Al2O3 Ceramic Substrates via Low-Temperature Pressureless Sintering

Metallized ceramic substrates are essential for power electronics, offering superior thermal and electrical conductivity. However, traditional metallization techniques, such as thick printed copper (TPC), face significant challenges, including weak bonding strength, high sintering temperatures, and complications associated with glass frit, which ultimately compromise device reliability and performance. To address these issues, this study presents an efficient method for fabricating high-performance copper (Cu) films on Al 2 O 3 ceramic substrates using low-temperature, pressureless sintering. By incorporating a magnetron-sputtered copper interlayer combined with printed copper paste, we eliminate the need for glass frit, a conventional component that often introduces defects. Through careful optimization of copper powder synthesis and paste formulation, we achieved dense, low-porosity Cu films sintered at just 300°C, which demonstrate exceptional electrical conductivity (1.7 × 10 7 S m −1 ) and shear strength (31.5 MPa). The sputtered copper interlayer significantly enhances the adhesion between the copper film and the ceramic substrate, minimizing delamination and improving mechanical integrity when compared to traditional sintering methods. This approach addresses key challenges in power device packaging, providing a cost-effective, reliable solution for low-temperature, high-performance interconnections. The results have wide-reaching implications for advancing electronic packaging, especially in power electronics, by enabling durable, efficient, and scalable manufacturing processes.