Patent ID: 6979652
Filing Date: 2005-12-27
Classification: H01L

Abstract:
1. A method of forming variable shaped features in a silicon substrate comprising: etching an opening having a first sidewalls section in a silicon substrate at a first etch rate; depositing a fluorocarbon polymer conformally on the first sidewalls section of the opening at a first deposition rate using a polymer forming gas so as to protect the first sidewalls section from further etching; performing a second silicon etching step at a second etch rate to expose a second sidewalls section below the first sidewalls section; depositing a fluorocarbon polymer conformally on the second sidewalls section of the opening at a second deposition rate using a polymer forming gas so as to protect the second sidewalls; and performing a third silicon etching step at a third etch rate to expose a third sidewalls section below the second sidewalls section, wherein the first, second and third sidewalls sections have different profiles.