Method of producing semiconductor

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.