The present invention relates to a method for preventing a metal corrosion in a semiconductor device. The present method includes the steps of etching of a metal layer in a chamber, the metal layer having a photoresist pattern thereon or thereover; oxidizing a surface of the metal layer using a plasma comprising N.sub.2O in the same chamber; and removing the photoresist. Therefore, metal corrosion as well as bridges between metal wirings can be suppressed or prevented, thereby improving the profile of metal layer and the reliability and yield of the semiconductor device.