Patent ID: 6159660
Filing Date: 2000-12-12
Classification: G03F,H01L

Abstract:
A method of patterning a layer of conducting material, comprising the steps of:providing an integrated circuit wafer having devices formed therein;forming a layer of conducting material on said integrated circuit wafer;forming a layer of photoresist on said layer of conducting material wherein said layer of photoresist is negative or positive photoresist;providing a projection mask wherein said mask contains a conductor pattern;providing means to illuminate said mask with a light source so that said light selectively passes through said mask,providing means to focus said light selectively passing through said mask whereby said conductor pattern is focussed at a focal plane;providing means to hold said integrated circuit wafer wherein said layer of photoresist is parallel to said focal plane;providing means to adjust the position of said layer of photoresist relative to said focal plane;adjusting the position of said layer of photoresist relative to said focal plane so that said layer of photoresist is a de-focus distance from said focal plane;exposing said layer of photoresist using said conductor pattern focussed at said focal plane after adjusting the position of said layer of photoresist relative to said focal plane;developing said layer of photoresist after exposing said layer of photoresist thereby forming a photoresist mask of said conductor pattern;etching said conductor pattern in said layer of conductor material using vertical anisotropic etching and said photoresist mask;removing said photoresist mask; andforming a layer of dielectric over said integrated circuit wafer after etching said conductor pattern in said layer of conductor material and removing said photoresist mask.