Semiconductor device and method for manufacturing the same

A semiconductor device includes: a first interlayer insulating layer disposed on a substrate; a first conductive line disposed in the first interlayer insulating layer and having a protrusion protruding above an upper side of the first interlayer insulating layer; an etch stop layer disposed on the first interlayer insulating layer and the first conductive line; and a via passing through the etch stop layer and contacting the first conductive line, wherein the etch stop layer includes a first etch stop layer having a curved shape in a cross-sectional view and a second etch stop layer disposed on the first etch stop layer and having a thickness variation. A method for manufacturing the semiconductor device is also provided.