Patent ID: 8071481
Filing Date: 2011-12-06
Classification: H01L

Abstract:
1. A method for forming a semiconductor structure, said method comprising: providing a silicon substrate having a substrate surface with at least a device structure disposed over a first portion of said substrate surface and a material layer disposed over a second portion of said substrate surface; removing said material layer from over said second portion of said substrate surface to result in said second portion of said substrate surface being an exposed substrate surface portion and said first portion of said substrate surface being a covered substrate surface portion covered by said device structure; etching said silicon substrate by performing a plurality of Br-based etch processes that selectively etch silicon, comprising a first Br-based etch step including nitrogen as a first etching gas and a second Br-based etch step that does not include nitrogen as a second etching gas; and after said etching, further etching said silicon substrate using an etch chemistry that includes F and Cl.