Patent ID: 6917110

Claim:
A semiconductor device comprising: a plurality of first interconnection layers formed on a semiconductor substrate at a prescribed interval; a first insular film, formed to fill up the clearance between said plurality of first interconnection layers, having an opening reaching said first interconnection layers; and a conductive plug charged in said opening of said first insulator film and formed to be in contact with said first interconnection layers; wherein an impurity is selectively introduced into a first region of said first insulator film in the vicinity of contact surfaces between said first interconnection layers and said conductive plug thereby selectively modifying said first region of said first region of said first insulator film, wherein said opening of said first insulator film is formed to expose the upper surfaces and the side surfaces of said first interconnection layers as well as a region of said first insulator film located under modified said first region, and a modified region is formed on said region of said first insulator film located under said first region exposed in said opening.