Method of producing semiconductor
In a conventional SGT production method, during dry etching for forming a pillar-shaped silicon layer and a gate electrode, an etching amount cannot be controlled using an end-point detection process, which causes difficulty in producing an SGT while stabilizing a height dimension of the pillar-shaped silicon layer, and a gate length. In an SGT production method of the present invention, a hard mask for use in dry etching for forming a pillar-shaped silicon layer is formed in a layered structure comprising a first hard mask and a second hard mask, to allow the end-point detection process to be used during the dry etching for the pillar-shaped silicon layer. In addition, a gate conductive film for use in dry etching for forming a gate electrode is formed in a layered structure comprising a first gate conductive film and a second gate conductive film, to allow the end-point detection process to be used during the dry etching for the gate electrode.
1. A method of producing a semiconductor device in which a source diffusion layer, a drain diffusion layer and a pillar-shaped semiconductor layer are vertically arranged on an upper side of a substrate in a layered manner, and a gate is arranged around a sidewall of the pillar-shaped semiconductor layer, wherein the pillar-shaped semiconductor layer is arranged on a semiconductor substrate, the pillar-shaped semiconductor layer has a third protective film formed on a top thereof, and a dielectric film is arranged on respective surfaces of the semiconductor substrate and the pillar-shaped semiconductor layer, the method comprising the steps of:
forming a first gate conductive film to cover a surface of the dielectric film;
forming, on a surface of the first gate conductive film, a second gate conductive film having a plasma emission characteristic different from that of the first gate conductive film;
flattening respective upper portions of the first and second gate conductive films by CMP, the third protective film being used as a stopper of CMP; and
anisotropically etching the first and second gate conductive films, wherein an intensity of plasma emission generated from the second gate conductive film is monitored during the etching to detect a change in the plasma emission intensity occurring when the second gate conductive film is etched away, to thereby detect an end-point of the etching for the first and second gate conductive films.
2. A method of producing a semiconductor device in which a source diffusion layer, a drain diffusion layer and a pillar-shaped semiconductor layer are vertically arranged on an upper side of a substrate in a layered manner, and a gate is arranged around a sidewall of the pillar-shaped semiconductor layer, wherein the pillar-shaped semiconductor layer is arranged on a semiconductor substrate, the pillar-shaped semiconductor layer has a third protective film formed on a top thereof, and a dielectric film is arranged on respective surfaces of the semiconductor substrate and the pillar-shaped semiconductor layer, the method comprising the steps of:
forming a first gate conductive film to cover a surface of the dielectric film;
forming, on a surface of the first gate conductive film, a second gate conductive film having a plasma emission characteristic different from that of the first gate conductive film;
forming, on a surface of the second gate conductive film, a third gate conductive film having a plasma emission characteristic different from that of the second gate conductive film;
flattening respective upper portions of the first, second and third gate conductive films by CMP, the third protective film being used as a stopper of CMP; and
anisotropically etching the first, second and third gate conductive films,
wherein the second gate conductive film is formed to become thinner than the first and third gate conductive films, and an intensity of plasma emission generated from the second gate conductive film is monitored during the etching to detect a change in the plasma emission intensity occurring when the second gate conductive film is etched away, to thereby detect an end-point of the etching for the first, second and third gate conductive films.
3. The method as defined in claim 2 , wherein the first gate conductive film and the third gate conductive film are made of an identical material.