MANUFACTURE OF SEMICONDUCTOR DEVICE

PROBLEM TO BE SOLVED: To provide a manufacturing method of a semiconductor device by which a Cu wiring layer formed as a lower wiring layer is not oxidized and, in addition, a via hole can be opened satisfactorily. SOLUTION: An interlayer insulating film 3 is formed on a Cu wiring layer 2 formed on a semiconductor substrate 1 as a lower wiring layer and a groove 5 which becomes a via hole is opened in the insulating film 3 until the Cu wiring layer 2 appears by using a resist 4 as a mask. Then another resist 7 is formed on the surface and only left on the internal walls of the groove 5 by exposing the resist for a period of time longer than that set in forming an ordinary mask pattern. Therefore, the groove 5 is opened by removing the resists 4 and 7 by using an O2 asher and a liquid chemical.