Role of surface contaminants in the deformation welding of gold to thick and thin films

The role of organic surface contaminants in the deformation welding of gold to thick and thin film conductors was investigated, employing shear tests to determine the strength of ball bonds. As was observed earlier for gold thin films, organic surface films play a dominant role in the deformation welding of gold to gold thick films. Gold thick films were found to be more tolerant to organic surface films than film gold. The contaminants evaluated (beeswax, halocarbon wax, and petrolatum) all degraded the weldability of gold more than atmospheric contamination. The gold--platinum thick films required higher temperatures than the gold metallizations for thermocompression welding.