Method of producing semiconductor device

Claim 1

A method of producing a semiconductor device, comprising the steps of: forming all desired semiconductor regions in a semiconductor substrate using masking films; removing all of the masking films used in forming the desired semiconductor regions within the semiconductor substrate to expose the entire surface of the semiconductor substrate; forming a first insulation film on the exposed surface of the substrate; selectively forming a polycrystalline silicon film on the surface of the first insulation film to provide covered and uncovered portions of the first insulation film at predetermined locations; and forming a second insulation film selectively at least on the uncovered portions of the first insulation film by using the selectively formed polycrystalline silicon film

Claim 2

A method of producing a semiconductor device, comprising the steps of: forming all desired semiconductor regions in a semiconductor substrate using masking films; removing all of the masking films used in forming the desired semiconductor regions within the semiconductor substrate to expose the entire surface of the semiconductor substrate; forming a first insulation film on the exposed surface of the substrate; selectively forming a polycrystalline silicon film on the surface of the first insulation film to provide covered and uncovered portions of the first insulation film at predetermined locations; and forming a second insulation film selectively at least on the uncovered portions of the first insulation film by using the selectively formed polycrystalline silicon film

Claim 17

A method of producing a semiconductor device, comprising the steps of: forming all desired semiconductor regions in a silicon semiconductor substrate using masking films; removing all of the masking films used in forming the desired semiconductor regions within the silicon semiconductor substrate to expose the entire surface of the semiconductor substrate; heating the silicon substrate in a mixed gas stream comprising hydrogen gas, oxygen gas and a gas of a halogen-containing compound to form a first silicon dioxide film on the exposed surface of the silicon substrate; thermally decomposing monosilane to form a polycrystalline silicon film on the surface of the first silicon dioxide film; selectively etching the polycrystalline silicon film to leave predetermined portions of the polycrystalline silicon film thereby to provide covered and uncovered portions of the first silicon dioxide film at predetermined locations; heating the silicon substrate in a mixed gas comprising hydrogen gas, oxygen gas and a gas of a halogen-containing compound to form a second silicon dioxide film over the uncovered portions of the first silicon dioxide film and the remaining predetermined portions of the polycrystalline silicon film, said second silicon dioxide film extending into the underlying silicon substrate beneath the uncovered portions of the first silicon dioxide film; and forming a third silicon dioxide film doped with phosphorus or a mixture of phosphorus and arsenic over the second silicon dioxide film by oxidizing monsilane in the presence of phosphorus or a mixture of phosphorus and arsenic.

Claim 18

A method of producing a semiconductor device, comprising the steps of: forming all desired semiconductor regions in a silicon semiconductor substrate using masking films; removing all of the masking films used in forming the desired semiconductor regions within the silicon semiconductor substrate to expose the entire surface of the semiconductor substrate; heating the silicon substrate in a mixed gas stream comprising hydrogen gas, oxygen gas and a gas of a halogen-containing compound to form a first silicon dioxide film on the exposed surface of the silicon substrate; thermally decomposing monosilane to form a polycrystalline silicon film on the surface of the first silicon dioxide film; selectively etching the polycrystalline silicon film to leave predetermined portions of the polycrystalline silicon film thereby to provide covered and uncovered portions of the first silicon dioxide film at predetermined locations; heating the silicon substrate in a mixed gas comprising hydrogen gas, oxygen gas and a gas of a halogen-containing compound to form a second silicon dioxide film over the uncovered portions of the first silicon dioxide film and the remaining predetermined portions of the polycrystalline silicon film, said second silicon dioxide film extending into the underlying silicon substrate beneath the uncovered portions of the first silicon dioxide film; and forming a third silicon dioxide film doped with phosphorus or a mixture of phosphorus and arsenic over the second silicon dioxide film by oxidizing monsilane in the presence of phosphorus or a mixture of phosphorus and arsenic.