Stress and wafer warpage analysis of GaN thin film induced by transfer bonding process on 200mm Si substrate

In this paper we used Finite Element Modeling (FEM) to investigate the wafer bow induced during the substrate transfer process for GaN LED on 200mm silicon wafer. The substrate transfer process is to transfer the thin GaN LED device layer to a carrier wafer using a permanent bonding layer. In this work two different bonding materials were benchmarked, a metallic CuSn alloy and a Benzocyclobutene (BCB) polymer. It is important to control the wafer bow during the process because the high wafer bow value may cause problem for further process steps, besides it affects process quality such as in lithography and can be a threat to the device reliability. It was found that the wafer bow changes during substrate transfer process. Metallic bond material introduces high bow values at the end of the substrate transfer process. Different compositions of metallic bond material inlfuence the final wafer bow.