Patent ID: 6498106
Filing Date: 2002-12-24
Classification: G03F,H01L

Abstract:
A process for etching a dual thickness oxide, comprising:providing a substrate on which is a layer of silicon oxide having a first thickness; coating the silicon oxide layer with a layer of photoresist, having a surface, and then patterning said photoresist layer to protect a part of said silicon oxide layer; exposing the photoresist layer to a gas plasma, at a pressure between about 0.95 and 1.15 torr, containing at least 95 percent oxygen by volume, at a power level that is less than about 300 watts, for between about 5 and 15 seconds, thereby removing unsaturated chemical bonds from the photoresist surface without etching the photoresist; etching all unprotected silicon oxide thereby reducing it to a second thickness; and then removing the layer of photoresist by means of a wet etch treatment.