Semiconductor device having a multilayer interconnection structure and fabrication process thereof

摘要

A multilayer interconnection structure includes a first interconnection layer (21Cu) having a copper interconnection pattern and a second interconnection layer having an aluminum interconnection layer (23) and formed on the first interconnection layer via an intervening interlayer insulation film (22), wherein a tungsten plug (22W) is formed in a via-hole (22V) formed in the interlayer insulation film so as to connect the first interconnection layer and the second interconnection layer electrically. The via-hole has a depth/diameter ratio of 1.25 or more, and there is formed a conductive nitride film (22A) between the outer wall of the tungsten plug and an inner wall of the via-hole such that the entirety of the conductive nitride film is formed of a conductive nitride.