Wafer Bevel Protection During Deep Reactive Ion Etching

During deep reactive ion etching of silicon used for through silicon via or deep trench isolation processing, the bevel of the wafer is also etched away. The etching of the bevel results in a deep step at the litho edge bead removal or in a degraded bevel shape, source of yield loss or processing issues. Two methods are proposed here to prevent the bevel degradation during deep reactive ion etching using an oxide hard mask. In one case this oxide mask is deposited in the second case the oxide hard mask is grown.