Abstract: The present invention provides a method of preventing corrosion of a titanium layer in a semiconductor wafer. The semiconductor wafer comprises a dielectric layer, a column-shaped tungsten plug embedded in the dielectric layer and having its top surface cut to be at the same level as that of the dielectric layer, a titanium layer positioned on the top of the dielectric layer and covering a portion of the top surface of the tungsten plug, a main conductive layer positioned on the surface of the titanium layer, a photoresist layer positioned on the surface of the main conductive layer, and a polymer layer scattered on the surface of the semiconductor wafer. The method is first to utilize a dry cleaning process to strip off the photoresist layer and the polymer layer, then to perform a nitridizing process to make the surface of the titanium layer exposed on the surface of the semiconductor wafer generate a titanium nitride layer.