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 ( 15 b) 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 ( 15 b) 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 ( 15 b) by etching selectively the etching stop insulating film ( 18 ) through the hole ( 28 ), and then forming a second-stage conductive plug ( 31 a) in the hole ( 28 ).