Evaporation vs. Sputtering of metal layers on the Backside of Silicon wafers

Abstract

We present the results of the differences observed between evaporated and sputtered backside metallization processes on silicon wafers: these two methods of fabricating metal layers and the activation of the backside semiconductor-metal contact follow different physical mechanisms. Differing crystalline structures of the metal layers can be observed and the thermal budget of the overall process of the wafer is affected in different ways. In this paper, we describe these differences, provide a description of the known physical and mechanical mechanisms and propose some models. Additionally, we report a few production issues and experiences