Spindle assembly for force controlled polishing

摘要

A spindle assembly for force controlled operation in applications such as the chemical mechanical planarization of semiconductor wafers includes an axially and rotatably movable spindle driven by a force producing device. The force producing device is controlled by a position feedback loop in a first mode of operation and a spindle force control feedback loop in a second mode of operation so that the same force producing device 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.