The corrosion resistance of several integrated-circuit metallization systems

Accelerated life data are presented on several integrated-circuit metallization systems including Al, Mo-Au, Ti-Pt-Au, and a new system W:Ti-Au, where the r-f-sputtered W:Ti layer is a pseudo-alloy of 10-20% Ti in W. Life tests include total water immersion, high-pressure steam, and 85°C/85% RH/bias on bare and plastic-encapsulated devices. Heat age and resistivity-ratio data are presented showing the metallurgical stability of the W:Ti-Au system. In order of decreasing corrosion resistance, Ti-Pt-Au > W:Ti-Au > > Mo-Au ≥ Al.