Method for manufacturing a bipolar integrated circuit device with a self-alignment base contact

Claim 1

A method for manufacturing a semiconductor integrated circuit device having a plurality of bipolar transistors at least one of which includes a base region, comprising the steps of: forming a conductive layer directly on the base region; forming an antioxidant insulation film of high insulation characteristic on said conductive layer; patterning said antioxidant insulation film to form an antioxidant insulation film pattern; overetching said underlying conductive layer using said antioxidant insulation film pattern as a mask to form a conductive layer pattern such that said antioxidant insulation film pattern overhangs said conductive layer pattern; thermally oxidizing the circumferential surface of said conductive layer pattern and an exposed part of said base region to grow a first thermally oxidized film on the circumferential surface of said conductive layer pattern and a second thermally oxidized film on the exposed part of said base region; said first thermally oxidized film being thicker than said second thermally oxidized film; removing said second thermally oxidized film on said base region by anisotropic etching with gaseous ions substantially vertically incident on the surface of said base region with said antioxidant insulation film pattern as a mask, thereby exposing a portion of said base region; and forming a base electrode wiring connected to said base region, said base electrode wiring covering said antioxidant insulation film pattern and said first thermally oxidized film.

Claim 2

A method for manufacturing a semiconductor integrated circuit device having a plurality of bipolar transistors at least one of which includes a base region, comprising the steps of: forming a conductive layer directly on the base region; forming an antioxidant insulation film of high insulation characteristic on said conductive layer; patterning said antioxidant insulation film to form an antioxidant insulation film pattern; overetching said underlying conductive layer using said antioxidant insulation film pattern as a mask to form a conductive layer pattern such that said antioxidant insulation film pattern overhangs said conductive layer pattern; thermally oxidizing the circumferential surface of said conductive layer pattern and an exposed part of said base region to grow a first thermally oxidized film on the circumferential surface of said conductive layer pattern and a second thermally oxidized film on the exposed part of said base region; said first thermally oxidized film being thicker than said second thermally oxidized film; removing said second thermally oxidized film on said base region by anisotropic etching with gaseous ions substantially vertically incident on the surface of said base region with said antioxidant insulation film pattern as a mask, thereby exposing a portion of said base region; and forming a base electrode wiring connected to said base region, said base electrode wiring covering said antioxidant insulation film pattern and said first thermally oxidized film.

Claim 5

A method for manufacturing a semiconductor integrated circuit device having a plurality of bipolar transistors at least one of which has a base region comprising the steps of: forming an insulation film on a part of the base region; forming conductive layers directly on said base region and on said insulation film; forming an antioxidant insulation film of high insulation characteristic on the conductive layer; patterning the antioxidant insulation film to form an antioxidant insulation film pattern; overetching the underlying conductive layer with the antioxidant insulation film pattern as a mask to form a conductive layer pattern such that the antioxidant insulation film pattern overhangs the conductive layer pattern; thermally oxidizing the circumferential surface of the conductive layer pattern and an exposed part of said base region to grow a first thermally oxidized film on the circumferential surface of the conductive layer pattern and a second thermally oxidized film on the exposed part of said base region, said first thermally oxidized film being thicker than said second thermally oxidized film; removing said second thermally oxidized film on said base region by anisotropic etching with gaseous ions substantially vertically incident on the surface of said base region with the antioxidant insulation film pattern as a mask, thereby forming a base contact hole; and forming a base electrode wiring connected to said base region, said base electrode wiring covering the antioxidant insulation film pattern and the first thermally oxidized film.

Claim 6

A method for manufacturing a semiconductor integrated circuit device having a plurality of bipolar transistors at least one of which has a base region comprising the steps of: forming an insulation film on a part of the base region; forming conductive layers directly on said base region and on said insulation film; forming an antioxidant insulation film of high insulation characteristic on the conductive layer; patterning the antioxidant insulation film to form an antioxidant insulation film pattern; overetching the underlying conductive layer with the antioxidant insulation film pattern as a mask to form a conductive layer pattern such that the antioxidant insulation film pattern overhangs the conductive layer pattern; thermally oxidizing the circumferential surface of the conductive layer pattern and an exposed part of said base region to grow a first thermally oxidized film on the circumferential surface of the conductive layer pattern and a second thermally oxidized film on the exposed part of said base region, said first thermally oxidized film being thicker than said second thermally oxidized film; removing said second thermally oxidized film on said base region by anisotropic etching with gaseous ions substantially vertically incident on the surface of said base region with the antioxidant insulation film pattern as a mask, thereby forming a base contact hole; and forming a base electrode wiring connected to said base region, said base electrode wiring covering the antioxidant insulation film pattern and the first thermally oxidized film.