Method for etching of mask layer and passivation layer of metal contact windows

The present invention relates to a method for etching mask and fuse passivation layers, which includes the following procedures: first, forming a mask layer and a patterned photoresist on a semiconductor base and some parts of the mask layer surface, respectively; then forming, in compliance with the formations, a sacrifice layer of thickness less than the thickness of the photoresist on the surface of the patterned photoresist thereby forming a ramp-shaped pattern on the side wall of the patterned photoresist layer; and finally using the patterned photoresist and the ramp-shaped sacrifice layer as masks to etch the mask layer to form several metal contact windows. In accordance with the present invention, undercut that generally occurs can be avoided.