Study of Direct Bonding Ceramics with Metal Using Sn2La Solder

Abstract

The aim of this research was to study the direct bonding of ceramic materials, mainly Al 2 O 3 and selected metals, with primary attention given to Cu substrate. Soldering was performed with Sn-based solder alloyed with 2% La. We found that the bond formation between Sn2La solder and Al 2 O 3 occurs at the activation of lanthanum phases in solder by ultrasound. Lanthanum in the solder becomes oxidised in air during the soldering process. However, due to ultrasonic activation, the lanthanum particles are distributed to the boundary with ceramic material. A uniformly thin layer containing La, 1.5 µ m in thickness, is formed on the boundary with Al 2 O 3 material, ensuring both wetting and joint formation. The shear strength with Al 2 O 3 ceramics is 7.5 MPa. Increased strength to 13.5 MPa was observed with SiC ceramics.