Abstract: In accordance with the objects of this invention a new method to prevent copper contamination of the intermetal dielectric layer during etching, CMP, or post-etching and post-CMP cleaning by forming a dielectric cap for isolation of the underlying dielectric layer is described. In one embodiment of the invention, a dielectric layer is provided overlying a semiconductor substrate. A dielectric cap layer is deposited overlying the dielectric layer. A via is patterned and filled with a metal layer and planarized. A copper layer is deposited overlying the planarized metal layer and dielectric cap layer. The copper layer is etched to form a copper line wherein the dielectric cap layer prevents copper contamination of the dielectric layer during etching and cleaning. In another embodiment of the invention, a dielectric layer is provided overlying a semiconductor substrate. A dielectric cap layer is deposited overlying the dielectric layer.