Temperature Dependence of Stress for Copper, Copper-Silver and Copper-Tin Films

1. IntroductionIn VLSI processing and other applications such as printed circuit boards thin films of copper, usually used as conductors, undergo thermal cycling. This thermal cycling can cause loss of adhesion and mechanical failures thus decreasing reliability of the devices[l–7]. Understanding thermally induced stress due to mismatch of thermal expansion may assist in generating designs, processes and material replacement for increased reliability. This paper reports studies of the temperature dependence of stresses for plated and sputtered copper and plated copper-silver and copper-tin alloys. Studies of thermally annealed plated copper and copper-tin alloys are also reported.