Processes for pre-tapering silicon or silicon-germanium prior to etching shallow trenches

摘要

A process for pre-tapering features in a material, such as silicon, prior to etching shallow trenches in the material includes opening a hard mask over the material such that first pre-tapered features are formed in the material. The process can include a hard mask overetch step, which modifies the profile of the first pre-tapered features to form second pre-tapered features in the material. Shallow trench isolation features are formed in the pre-tapered material.