Patent ID: 6706638
Filing Date: 2004-03-16
Classification: H01L

Abstract:
A method of forming an opening in a dielectric layer, comprising:providing a substrate; forming a doped dielectric layer on the substrate; forming a undoped dielectric layer on the doped dielectric layer; forming a mask on the undoped dielectric layer, wherein the mask has a first opening therein for exposing a portion of the undoped dielectric layer; performing an ion implantation step with the mask on the undoped dielectric layer, so that a doped region is formed in the exposed portion of the undoped dielectric layer below the first opening, leaving the exposed portion of the undoped dielectric layer below the doped region undoped, wherein a depth of the doped region does not exceed a thickness of the undoped dielectric layer; performing a chemical vapor etching step with the mask on the undoped dielectric layer to remove the doped region, thereby forming a second opening in the undoped dielectric layer, wherein the second opening exposes the exposed portion of the undoped dielectric layer below the doped region; and performing a dry etching step with the mask on the undoped dielectric layer, so that the exposed portion of the undoped dielectric layer below the doped region and a portion of the doped dielectric layer below the second opening are removed to expose a portion of the substrate.