Patent ID: 8299619

Claim:
A semiconductor device having a multilayer interconnection structure, said multilayer interconnection structure comprising at least a first interconnection layer and a second interconnection layer formed over or under said first interconnection layer, said first interconnection layer comprising a first conductor pattern embedded in a first interlayer insulation film and constituting a part of an interconnection pattern, said second interconnection layer comprising a second conductor pattern embedded in a second interlayer insulation film and constituting a part of said interconnection pattern, said second conductor pattern having an extension part extending in a layer identical to said second conductor pattern, said second conductor pattern being electrically connected to said first conductor pattern at a first part of said extension part by a via-plug, said extension part having a second part extending beyond said via-plug, said extension part having a first width in said first part and a second width narrower than said first width in said second part, each of said second conductor pattern, said extension part and said via-plug forming a damascene structure.