Patent ID: 7432165

Claim:
A method for production of a semiconductor memory device composed of a plurality of memory cells arranged therein, each memory cell consisting of a memory capacitor with a memory node electrode and a transistor, said method comprising the steps of: forming a plurality of trenches side by side in a substrate; forming a plate electrode which reaches a prescribed depth from the surface of the inner wall of said trench; forming a capacitor insulating film which covers the surface of the inner wall of said trench; filling said trench to form sad memory node electrode, with said capacitor insulating film interposed; forming an interlayer insulating film over the entire surface of said substrate and said memory node electrode; forming a semiconductor layer on said interlayer insulating film; making a contact hole which reaches said memory node electrode from the surface of said semiconductor layer; forming a cylindrical insulating film on the surface of the side wall of said contact hole; filling said contact hole with a conductive material to form a memory node contact plug inside said cylindrical insulating film; forming the upper surface of said cylindrical insulating film lower than the surface of said semiconductor layer and said memory node contact plug; burying a conductive film in the recess surrounded by said semiconductor layer, the side close to said cylindrical insulating film of said memory node contact plug, and the upper surface of said cylindrical insulating film, and forming a metallized region integrally with at least part of the surface of said semiconductor layer and at least part of the surface of said memory node contact plug such that the metallized region electrically connects said semiconductor layer to said memory node contact plug and integrally with said conductive film on at least part of the surface of said semiconductor layer and at least part of the surface of said memory node contact plug, wherein, said metallized region is formed such that the metallized region extends over the upper part of said cylindrical insulating film which is integral with at least part of the surface of said semiconductor layer and at least part of the surface of said memory node contact plug.