Abstract: A system for polishing a substrate has a controller, pressure source, a platen, and a carrier for handling the substrate. The carrier must be able to detect if a substrate is present. In either the case of a false detection of substrate presence or the failure to detect substrate presence, the likely result is damaged substrates, wasted polishing consumables, and down time of the manufacturing facility. Detection is achieved by the substrate causing movement of a plunger and by such movement resulting in a pressure differential that is detected. The reliability of this detection is improved by one or more of a precise relationship of the plunger to a plate that applies pressure to the substrate, a controlled seal that is ensured of being broken when the plunger is moved by the presence of a substrate, and proper spring pressure applied to the plunger to prevent spurious plunger movement.

Abstract: A system for polishing a substrate has a controller, pressure source, a platen, and a carrier for handling the substrate. The carrier must be able to detect if a substrate is present. In either the case of a false detection of substrate presence or the failure to detect substrate presence, the likely result is damaged substrates, wasted polishing consumables, and down time of the manufacturing facility. Detection is achieved by the substrate causing movement of a plunger and by such movement resulting in a pressure differential that is detected. The reliability of this detection is improved by one or more of a precise relationship of the plunger to a plate that applies pressure to the substrate, a controlled seal that is ensured of being broken when the plunger is moved by the presence of a substrate, and proper spring pressure applied to the plunger to prevent spurious plunger movement.