Method for forming electrical contacts in a semiconductor device

Claim 1

A method of making a wiring conductor for a semiconductor device, comprising the steps of: forming a lower metal wiring conductor over a semiconductor substrate; introducing a first reactive gas including tetraethyl orthosilicate TEOS and oxygen O 2 over the semiconductor substrate to form a first plasma oxide film in a plasma CVD process; coating the semiconductor substrate with a glass film; heating the semiconductor substrate; flattening the surface of the semiconductor substrate over which the lower metal wiring conductor, the first plasma oxide film and the glass film are formed; introducing a second reactive gas including TEOS and O 2 over the semiconductor substrate to form a second plasma oxide film in a plasma CVD process, at least a part of the second plasma oxide film being formed on the glass film; forming an ozone-TEOS oxide film on the second oxide film in a low pressure CVD process, using TEOS and ozone O 3 as a third reactive gas in place of the second reactive gas; forming a photoresist layer on the ozone-TEOS oxide film and patterning the photoresist layer so as to form an opening above a part of the lower metal wiring conductor; making a contact hole reaching the lower metal wiring conductor by etching the ozone-TEOS oxide film and the second plasma oxide film, with the photoresist layer used as a mask; removing the photoresist layer; and forming an upper metal wiring conductor on the ozone-TEOS oxide film, the upper metal wiring conductor filling the contact hole and being connected with the lower metal wiring conductor; wherein said etching comprises a step of wet etching at least an upper part of the ozone-TEOS oxide film to form a taper portion in an upper portion of the contact hole, and a step of an anisotropic etching at least the second plasma oxide film to form a lower portion of the contact hole which reaches the lower metal wiring conductor.

Claim 2

A method of making a wiring conductor for a semiconductor device, comprising the steps of: forming a lower metal wiring conductor over a semiconductor substrate; introducing a first reactive gas including tetraethyl orthosilicate TEOS and oxygen O 2 over the semiconductor substrate to form a first plasma oxide film in a plasma CVD process; coating the semiconductor substrate with a glass film; heating the semiconductor substrate; flattening the surface of the semiconductor substrate over which the lower metal wiring conductor, the first plasma oxide film and the glass film are formed; introducing a second reactive gas including TEOS and O 2 over the semiconductor substrate to form a second plasma oxide film in a plasma CVD process, at least a part of the second plasma oxide film being formed on the glass film; forming an ozone-TEOS oxide film on the second oxide film in a low pressure CVD process, using TEOS and ozone O 3 as a third reactive gas in place of the second reactive gas; forming a photoresist layer on the ozone-TEOS oxide film and patterning the photoresist layer so as to form an opening above a part of the lower metal wiring conductor; making a contact hole reaching the lower metal wiring conductor by etching the ozone-TEOS oxide film and the second plasma oxide film, with the photoresist layer used as a mask; removing the photoresist layer; and forming an upper metal wiring conductor on the ozone-TEOS oxide film, the upper metal wiring conductor filling the contact hole and being connected with the lower metal wiring conductor; wherein said etching comprises a step of wet etching at least an upper part of the ozone-TEOS oxide film to form a taper portion in an upper portion of the contact hole, and a step of an anisotropic etching at least the second plasma oxide film to form a lower portion of the contact hole which reaches the lower metal wiring conductor.

Claim 3

A method of making a wiring conductor for a semiconductor device, comprising the steps of: forming a lower metal wiring conductor over a semiconductor substrate; introducing a first reactive gas including tetraethyl orthosilicate TEOS and oxygen O 2 over the semiconductor substrate to form a plasma oxide film in a plasma CVD process; coating the semiconductor substrate with a glass film; heating the semiconductor substrate; flattening the surface of the semiconductor substrate over which the lower metal wiring conductor, the plasma oxide film and the glass film have been formed; forming an ozone-TEOS oxide film on the plasma oxide film in a low pressure CVD process, using TEOS and ozone O 3 as a second reactive gas in place of the first reactive gas, at least a part of the ozone-TEOS oxide film being formed on-the glass film; forming a photoresist layer on the ozone-TEOS oxide film and patterning the photoresist layer to form an opening above a part of the lower metal wiring conductor; making a contact hole reaching the lower metal wiring conductor by etching the ozone-TEOS oxide film and the plasma oxide film, with the photoresist layer used as a mask; removing the photoresist layer; and forming an upper metal wiring conductor on the ozone-TEOS oxide film, the upper metal wiring conductor filling the contact hole and being connected with the lower metal wiring conductor; wherein said etching comprises a step of wet etching at least an upper part of the ozone-TEOS oxide film to form a taper portion in an upper portion of the contact hole, and a step of an anisotropic etching at least the plasma oxide film to form a lower portion of the contact hole which reaches the lower metal wiring conductor.

Claim 4

A method of making a wiring conductor for a semiconductor device, comprising the steps of: forming a lower metal wiring conductor over a semiconductor substrate; introducing a first reactive gas including tetraethyl orthosilicate TEOS and oxygen O 2 over the semiconductor substrate to form a plasma oxide film in a plasma CVD process; coating the semiconductor substrate with a glass film; heating the semiconductor substrate; flattening the surface of the semiconductor substrate over which the lower metal wiring conductor, the plasma oxide film and the glass film have been formed; forming an ozone-TEOS oxide film on the plasma oxide film in a low pressure CVD process, using TEOS and ozone O 3 as a second reactive gas in place of the first reactive gas, at least a part of the ozone-TEOS oxide film being formed on-the glass film; forming a photoresist layer on the ozone-TEOS oxide film and patterning the photoresist layer to form an opening above a part of the lower metal wiring conductor; making a contact hole reaching the lower metal wiring conductor by etching the ozone-TEOS oxide film and the plasma oxide film, with the photoresist layer used as a mask; removing the photoresist layer; and forming an upper metal wiring conductor on the ozone-TEOS oxide film, the upper metal wiring conductor filling the contact hole and being connected with the lower metal wiring conductor; wherein said etching comprises a step of wet etching at least an upper part of the ozone-TEOS oxide film to form a taper portion in an upper portion of the contact hole, and a step of an anisotropic etching at least the plasma oxide film to form a lower portion of the contact hole which reaches the lower metal wiring conductor.

Claim 5

A method of making a semiconductor device, comprising the steps of: providing a first insulating film in which a contact hole is formed; forming a second insulating film on the first insulating film, the second insulating film having a hydrophobic surface; forming and patterning a photoresist film on the second insulating film, the photoresist film having an opening directly above the contact hole to be formed; performing wet etching on at least a part of the second insulating film with the photoresist film used as a mask; and performing anisotropic etching on the first insulating film with the photoresist film used as a mask, wherein: the second insulating film is made from a mixed gas of tetraethyl orthosilicate TEOS and ozone O 3 in a low pressure CVD process; and a ratio of the flow of TEOS to the flow of O 3 is adjusted in a range of between 1:1 and 1:10 when the second insulating film is formed.

Claim 6

A method of making a semiconductor device, comprising the steps of: providing a first insulating film in which a contact hole is formed; forming a second insulating film on the first insulating film, the second insulating film having a hydrophobic surface; forming and patterning a photoresist film on the second insulating film, the photoresist film having an opening directly above the contact hole to be formed; performing wet etching on at least a part of the second insulating film with the photoresist film used as a mask; and performing anisotropic etching on the first insulating film with the photoresist film used as a mask, wherein: the second insulating film is made from a mixed gas of tetraethyl orthosilicate TEOS and ozone O 3 in a low pressure CVD process; and a ratio of the flow of TEOS to the flow of O 3 is adjusted in a range of between 1:1 and 1:10 when the second insulating film is formed.