A workpiece is supported on the backside in a vacuum chamber while leaving at least a peripheral annular portion of a backside of the workpiece exposed. The process first increases the temperature of the workpiece starting at a temperature below about 200 degrees C. The edge of the workpiece is confined so as to establish a gap at the edge on the order of about 1% of the diameter of the chamber, the gap corresponding to a boundary between an upper process zone containing the front side and a lower process zone containing the backside. Before the workpiece temperature exceeds about 200 degrees C., backside polymer is removed using a first plasma containing polymer etch species in the lower process zone. After the workpiece temperature reaches about 300 degrees C., photoresist is stripped from the workpiece front side using by-products of a second plasma containing a photoresist strip species in the upper process zone.