Patent ID: 7682986
Filing Date: 2010-03-23
Classification: H01L

Abstract:
1. A method for etching an ultra high aspect ratio feature in a dielectric layer through a carbon based mask, comprising: a first selectively etching the dielectric layer with respect to the carbon based mask, wherein the first selectively etching provides a selective etch of the dielectric layer, while depositing a net deposition of a fluorocarbon based polymer on the carbon based mask; stopping the selective etch; selectively remove the fluorocarbon polymer with respect to the carbon based mask, so that the carbon based mask remains, using a trimming; stopping the selectively removing the fluorocarbon polymer; and a second selectively etching the dielectric layer with respect to the carbon based mask, wherein the second selectively etching provides a selective etch of the dielectric layer, while depositing a net deposition of a fluorocarbon based polymer on the carbon based mask.