Patent ID: 6143649
Filing Date: 2000-11-07
Classification: H01L

Abstract:
A method for making a semiconductor device having a gradual slope contact comprising the steps of:forming a layer of dielectric material on a substrate, wherein said dielectric material is selected from the group consisting of silicon oxide, silicon nitride and polyimide film and wherein said substrate is selected from the group consisting of aluminum, copper and polycrystalline silicon;forming a layer of conductive material within said layer of dielectric material, said layer of conductive material being surrounded by said layer of dielectric material;depositing a layer of hard mask material on said layer of dielectric material, said hard mask material being selected from the group consisting of tungsten, tungsten silicide, polycrystalline silicon, titanium, titanium nitride, titanium silicide and titanium-tungsten alloys;forming a photoresist layer on said layer of hard mask material;exposing said photoresist layer to form a pattern on said photoresist layer;etching said layer of hard mask material according to said pattern on said photoresist layer to expose said layer of dielectric material and to form sidewalls in said exposed portion of said layer of dielectric material;removing said photoresist layer;anisotropically etching said layer of hard mask with an inert material to form gradual slope contacts on said layer of hard mask material;redepositing eroded hard mask material from said anisotropic etching step onto said sidewalls of said exposed layer of dielectric material;etching said dielectric material to expose a portion said layer of conductive material; andforming a metal interconnect with said exposed portion of said conductive layer, wherein said metal interconnect is selected from the group consisting of aluminum, copper, gold, aluminum-titanium alloys and aluminum-copper alloys.