SPINDLE ASSEMBLY FOR FORCE CONTROLLED POLISHING

摘要

A spindle assembly (10) for force controlled operation in applications such as the chemical mechanical planarization of semiconductor wafers includes an axially and rotatably moveable spindle (14) driven by a force producing device (14). The force producing device (14) is controlled by a position feedback loop (18) in a first mode of operation and a spindle force control feedback loop (22) in a second mode of operation so that the same force producing device (14) controls spindle movement in the first mode of operation and maintains a constant pressure on a workpiece based on the detected applied pressure in the second mode of operation.