Patent ID: 6569774
Filing Date: 2003-05-27
Classification: H01L

Abstract:
A method of etching a layer of silicon oxide, comprising the steps of:providing a substrate comprising a layer of silicon oxide and a mask layer overlying the silicon oxide layer, the mask layer having at least one opening to expose an area of the silicon oxide layer; etching the layer of silicon oxide to provide an opening extending through the layer of silicon oxide to an aspect ratio of at least about 2:1, the etching being performed by exposing the layer of silicon oxide to a first etch gas in an ionized state in a reaction chamber of a plasma generating device, the first etch gas including at least one organic fluorocarbon and 0 to about 2% by volume of one or more nitrogen-comprising gases, based on the total volume of the first etch gas, whereby substantially no polymeric material is formed on the mask layer during the etching step; and etching the layer of silicon oxide to increase the opening through the silicon oxide layer; the etching being performed by alternately exposing the layer of silicon oxide to the first etch gas and a second etch gas in an ionized state in a reaction chamber of a plasma generating device until the opening is extended to a depth; the second etch gas including at least one fluorocarbon and at least one nitrogen-comprising gas in an amount effective to provide formation of a layer of polymeric material on the mask layer during the etching step; whereby the silicon oxide layer is exposed to the second gas to form a layer of polymeric material on the mask, and to the first etch gas upon depositing on the photoresist a layer of the polymeric material that constricts the opening to remove at least a portion of the polymeric material and reduce the constriction of the opening.