Isolation trench through backside of substrate

Abstract

Among other things, one or more semiconductor arrangements comprising isolation trenches, and techniques for forming such isolation trenches are provided. A substrate comprises a front side surface and a backside surface. One or more devices are formed over the front side surface. A wet etch is performed to form a tapered portion of an isolation trench. A dry etch is performed to form a non-tapered portion of the isolation trench. Because both the wet etch and the dry etch are performed, etching time is reduced compared to merely using the dry etch due to the wet etch having a relatively faster etch rate than the dry etch. In an embodiment, the isolation trench provides isolation for a current leakage path associated with a device or other material formed over the front side surface. In an embodiment, metal is formed within the isolation trench for backside metallization.