Patent ID: 6479356
Filing Date: 2002-11-12
Classification: H01L,Y10S

Abstract:
A method for manufacturing a semiconductor device comprising the steps of:forming a base constituted either by a substrate including first impurities at a first predetermined concentration or by wells which include said first impurities at said first predetermined concentration and which are formed on a substrate; forming on said base an interlayer film having gate-use openings over a gate region; wherein said step of forming said interlayer film further comprises the steps of: forming in a layered manner a bottom oxide film, a middle nitride film and a top oxide film on said base; removing those portions of said top oxide film which correspond to said gate region under etching conditions affording a sufficiently high selection ratio with respect to said middle nitride film; and removing those portions of said middle nitride film which correspond to said gate region under etching conditions affording a sufficiently high selection ratio with respect to said bottom oxide film; forming side walls of predetermined thickness over an inner surface of each of said gate-use openings; using the side walls as a mask, implanting into said gate-use openings ions of second impurities of a type identical to that of said first impurities in order to form, in the vicinity of a surface of said base, a high-concentration channel injection region which is smaller than said gate region and which includes said second impurities at a second predetermined concentration higher than said first predetermined concentration; and ion implanting impurities of a conductivity type different from that of the first and second impurities to form a first and a second source drain region which are respectively arranged on opposite sides of said gate region, leaving first and second low-concentration channel injection regions on each side of, and of the same conductivity type as, the high-concentration channel injection region, which low concentration and high-concentration channel injection regions extend from an upper surface of the base, the method further comprising the sequential steps of: removing said side wall; and forming a gate insulation film and gate electrodes on said gate region; wherein the steps of removing said side walls and forming said gate insulation film and gate electrodes are carried out after said step of forming said high-concentration channel injection region and before said step of forming said first and said second source drain region.