Method of making semiconductor devices

Claim 1

A method of making a semiconductor device comprising the successive steps of: (1) forming an anti-oxidation film pattern within a semiconductor substrate by ion implantation with a thin region of the semiconductor substrate remaining intact above the anti-oxidation film pattern so formed; (2) oxidizing the entire surface of the semiconductor substrate including the semiconductor layer on said anti-oxidation film pattern using the thus-formed anti-oxidation film pattern as a selective oxidation mask thereby leaving a resion of said substrate which is under said anti-oxidation film pattern unoxidized while protecting at least the brim portions of the anti-oxidation film pattern from exposure to the oxidizing atmosphere while producing a silicon dioxide coating adapted for use as a field oxide, and continuing the oxidation until the resultant oxidized regions adjacent and around the anti-oxidation film pattern, except those regions directly above it, have bottom faces deeper than the bottom face of said anti-oxidation film pattern in the semiconductor substrate while substantially suppressing irregular oxidation about the edges of the anti-oxidation film pattern; (3) removing said oxidized surface regions overlying said anti-oxidation film while only partially removing said oxidized regions formed directly on said semiconductor substrate thereby exposing the entire surface of said anti-oxidation film pattern; and thereafter (4) removing said anti-oxidation film.

Claim 2

A method of making a semiconductor device comprising the successive steps of: (1) forming an anti-oxidation film pattern within a semiconductor substrate by ion implantation with a thin region of the semiconductor substrate remaining intact above the anti-oxidation film pattern so formed; (2) oxidizing the entire surface of the semiconductor substrate including the semiconductor layer on said anti-oxidation film pattern using the thus-formed anti-oxidation film pattern as a selective oxidation mask thereby leaving a resion of said substrate which is under said anti-oxidation film pattern unoxidized while protecting at least the brim portions of the anti-oxidation film pattern from exposure to the oxidizing atmosphere while producing a silicon dioxide coating adapted for use as a field oxide, and continuing the oxidation until the resultant oxidized regions adjacent and around the anti-oxidation film pattern, except those regions directly above it, have bottom faces deeper than the bottom face of said anti-oxidation film pattern in the semiconductor substrate while substantially suppressing irregular oxidation about the edges of the anti-oxidation film pattern; (3) removing said oxidized surface regions overlying said anti-oxidation film while only partially removing said oxidized regions formed directly on said semiconductor substrate thereby exposing the entire surface of said anti-oxidation film pattern; and thereafter (4) removing said anti-oxidation film.