METHOD FOR MANUFACTURING SEMICONDUCTOR INTEGRATED CIRCUIT DEVICE

摘要

PROBLEM TO BE SOLVED: To improve the reliability and manufacturing yield of a minute MISFET(metal insulator semiconductor filed effect transistor) by suppressing the recess of a silicon oxide film being buried in an element separation groove. SOLUTION: At the lower part of a silicon nitride film 3 that becomes a mask when a substrate 1 of an element separation region is etched for forming a groove 5a, an amorphous silicon film (buffer film) 16 is provided. When the silicon nitride film 3 and the amorphous silicon film 16 are eliminated after the element separation groove is formed, the surface of a silicon oxide film 7 being buried to the element separation groove is set higher by the amount of the film thickness of the silicon nitride film 3 and the amorphous silicon film 16, thus preventing the height of the surface from greatly retreating (being recessed) downward as compared with the surface of the substrate 1 of an active region even when the silicon oxide film 7 is etched in a subsequent wet etching process.