Method and apparatus for using across wafer back pressure differentials to influence the performance of chemical mechanical polishing

摘要

Methods and apparatus for planarizing the surface of a semiconductor wafer by applying non-uniform pressure distributions across the back side of the wafer are disclosed. According to one aspect of the present invention, a chemical mechanical polishing apparatus for polishing a first surface of a semiconductor wafer includes a polishing pad which polishes the first surface of the semiconductor wafer. The apparatus also includes a first mechanism which is used to hold, or otherwise support, the wafer during polishing, and a second mechanism that is used to apply a non-uniform pressure distribution through the first mechanism, directly onto a second surface of the wafer. The second mechanism is further used to facilitate polishing the first surface of the semiconductor wafer such that the first surface of the semiconductor wafer is evenly polished. In one embodiment, the second mechanism is arranged to apply both positive pressure and negative pressure substantially simultaneously across the second surface of the semiconductor wafer.