Method and apparatus for using pressure differentials through a polishing pad to improve performance in chemical mechanical polishing

摘要

Methods and apparatus for planarizing the surface of a semiconductor wafer by applying non-uniform pressure distributions to a polishing pad are disclosed. According to one aspect of the present invention, a chemical mechanical polishing apparatus for polishing a surface of a semiconductor wafer includes a polishing pad with a first surface and a second surface. The first surface of the polishing pad is arranged to contact the surface of the semiconductor wafer in order to polish the surface of the semiconductor wafer. The apparatus also includes a mechanism which is used to apply a non-uniform pressure distribution over the second surface of the polishing pad, wherein applying the non-uniform pressure distribution to the polishing pad facilitates evenly polishing the surface of the semiconductor wafer. In one embodiment, the mechanism for applying the non-uniform pressure distribution to the polishing pad is an air bladder arrangement.