Effect of Surface Contamination on the Thermocompression Bondability of Gold

The recent development of a microshear test has made possible the quantitative study of the effect of surface contamination on thermocompression ball bonding of gold to gold metallization. Contarninant films were characterized by Auger electron spectroscopy and low energy ion spectroscopy. The thermocompression gold bonding process was found to be highly temperature dependent when organic films, which are barriers to metallic bonding, are present. Much of this temperature dependence could.be eliminated by rernoving the contaminant films by uV radiation prior to thermocompression bonding. Post-heat treatment resulted in the growth of metallic bond inter´faces, presumably by sintering mechanisms.