Patent ID: 7390745

Claim:
A method of patterning a Si-containing material comprising: providing a lithographically patterned photoresist over a crystalline Si-containing material, said lithographically patterned photoresist including at least one predetermined patterned shape having at least one topographic edge that has rounded corners; transferring said at least one predetermined patterned shape having at least one topographic edge with rounded corners into said crystalline Si-containing material by a first etching process providing a first patterned crystalline Si-containing material including at least one patterned shape having at least one topographic edge with rounded corners; and removing said rounded corners of said first patterned crystalline Si-containing material utilizing a second etching process to provide a second patterned crystalline Si-containing material including at least one desired patterned shape having at least one topographic edge that has substantially uniformly straight sides or edges and substantially square corners, said second etching process comprises a crystallographic etching step that etches along different crystal planes within the crystalline Si-containing material.