FORMING METHOD OF INTERPOLY INSULATING FILM

摘要

PROBLEM TO BE SOLVED: To obtain an interpoly insulating film free from ONO defects by a method wherein a nitride film is formed on a lower polysilicon layer under conditions of specific temperatures at a specific film forming rate/minute. SOLUTION: A first oxide film 22 is formed by oxidizing the surface of a lower polysilicon layer 20. A nitride film 24 is formed on the first oxide film 22 at temperatures lower than 700 deg.C at a growth rate of below 7Å/minute, the surface of the nitride film 24 is oxidized for the formation of a second oxide film 26, and an upper polysilicon layer 28 is formed thereon. By this setup, when the second oxide film of an interpoly insulating film is formed by oxidation, it can be prevented from varying thickness, Therefore, an interpoly insulating film cart be improved in yield.