US Patent 7192862 Semiconductor device and method of manufacturing the same

A manufacturing method of a semiconductor device comprises the steps of forming an etching stop insulating film (18) that covers at least side surfaces of a wiring (16) in a first region (2) and a first-stage conductive plug (15b) in a second region (3), then forming insulating films (20, 28) on the etching stop insulating film (18) and the wiring (16), then forming a hole (28) on a first-stage conductive plug (15b) by etching a part of the insulating films (20, 28) until the etching stop insulating film (18) is exposed, then exposing an upper surface of the first-stage conductive plug (15b) by etching selectively the etching stop insulating film (18) through the hole (28), and then forming a second-stage conductive plug (31a) in the hole (28).