Silver oxalate-based solders: New materials for high thermal conductivity microjoining

Micrometric oxalate powders can be decomposed starting from temperatures as low as 90°C, leading to the formation of temporary nanometric grains of metallic silver with a high propensity for sintering. The decomposition being highly exothermic, this additional energy favours the sintering, i.e. the soldering, process. Solders processed at 300°C and very low pressure (<0.5 MPa) displayed a thermal conductivity close to 100 W m-1 K-1, making silver oxalate very promising for safe, moderate temperature and very low pressure bonding.