The invention provides a semiconductor device and a method of manufacturing a semiconductor device. A semiconductor device includes: a substrate (1); a wiring (6) formed above the substrate (1); a titanium nitride film (7) formed on the wiring (6); an oxide film (3) formed on the titanium nitride film (7); a silicon nitride film (4) formed on the oxide film (3); and a pad portion (8) exposing thewiring (6), and formed at a place where a first opening portion (91) formed in the silicon nitride film (4) and a second opening portion (92) formed in the titanium nitride film (7) overlap with eachother in plan view, and being inside a third opening portion (93) formed in the oxide film (3) in plan view, wherein the semiconductor device (10) where the silicon nitride film (4) is formed on top of and in contact with the titanium nitride film (7) inside the third opening portion (93) in plan view is manufactured. Even if a silicon oxide film is provided on the anti-reflection film containingtitanium nitride, the titanium nitride which forms the anti-reflection film is difficult to corrode, and the number of man-hours in manufacturing is small.