Abstract
Solid-Liquid Interdiffusion (SLID) bonding has received substantial interest, primarily due to its ability to withstand higher temperatures than the bonding temperature. Whereas SLID bonding typically is performed in the range of normal solder temperatures, the remelting temperature is far higher. This makes SLID very promising for high-temperature applications, but it is also attractive from the viewpoint of creating well-defined, thin-layer metallic joints. This paper presents our work in the Cu-Sn, Au-Sn and Au-In SLID systems. For all these three systems we obtain well-defined layered bond structures with high strength. We verify experimentally that they are all solid to temperatures higher than 300 °C, being substantially higher than the respective melting temperatures of the initial low-temperature metal. For Au -In, a substantial increase in the bond strength at a die shear temperature of 300 °C is explained by an occurring phase transition. We show that a Au-Sn SLID assembly of materials with different Coefficients of Thermal Expansion can withstand thermal storage followed by thermal cycling, and that Au-Sn SLID also is compatible with bonding of rough substrates.
