JPS6481357A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent a breakdown strength and wiring resistance from decreasing due to the use of an Si3N4 film cell gate by forming the sidewall film of a thick insulating film on the sidewall of a memory cell gate. CONSTITUTION:An isolating thick field SiO2 film 52 is formed in an Si substrate 51, a gate SiO2 film 55, a gate Si3N4 film 54, and a first gate polysilicon film 53 are sequentially formed, and a capacitor 56 is formed by photolithographic etching. Then, an SiO2 film or a PSG film 57 is deposited as an insulating film by a normal pressure CVD method on a whole surface. In this case, the film thickness t1 on the film 52 becomes larger than that t2 on the substrate 51. When the film 57 is so etched as to remove only the film thickness of the t2, an insulating film 62 remains on the film 52, and a sidewall film 63 thicker than the film 53 remains on the sidewall of the film 53. The breakdown strength characteristics of a transfer electrode 68 to be formed in later step and the film 53 are improved due to the remainder of the film 63.