摘要 |
A polishing head for polishing a semiconductor wafer includes a housing, a wafer carrier movably mounted to the housing, and a pad dressing element movably mounted to the housing. The wafer carrier forms a wafer-supporting surface, and the dressing element surrounds the wafer-supporting surface. A first fluid actuator is coupled to the dressing element to bias the pad dressing element with respect to the housing, and a second fluid actuator is coupled to the wafer carrier to bias the wafer carrier with respect to the housing. First and second fluid conduits are coupled to the first and second actuators, respectively, such that fluid pressures in the first and second actuators are separately and independently adjustable with respect to one another. Biasing forces on the dressing element can thereby be dynamically adjusted with respect to biasing forces on the carrier during a polishing operation.
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