Patent ID: 6977209

Claim:
A method for manufacturing a semiconductor memory device comprising the steps of: depositing on a semiconductor substrate a first insulating film and then depositing a first electrically conductive film on said first insulating film; depositing a second insulating film on said first electrically conductive film; patterning a laminated film composed of said first insulating film, first electrically conductive film and the second insulating film to form a control gate; depositing a third insulating film on the entire surface of said substrate; depositing a second electrically conductive film on the entire surface of said substrate and subsequently processing said second electrically conductive film in the form of a sidewall on a sidewall section of said control gate which is covered by said third insulating film; performing ion injection with the control gate and the sidewall of said second electrically conductive film as a mask to form a diffusion region in the substrate surface by self-alignment; forming a fourth insulating film on the entire substrate surface and subsequently exposing an upper portion of said sidewall of said second electrically conductive film by polishing or etchback; and depositing a third electrically conductive film on the entire substrate surface and subsequently removing said third electrically conductive film and the sidewall of said second electrically conductive film to form a word line.