Patent ID: 7893697
Filing Date: 2011-02-22
Classification: G01B,H01L

Abstract:
1. A sensor for sensing a shape of a gap between the sensor while resting on a platen and a showerhead within a semiconductor processing chamber, the sensor including: a housing; a power source disposed within the housing; wireless communication circuitry coupled to the power source; a controller coupled to wireless communication circuitry and to the power source; a plurality of capacitive plates, each forming a capacitor with the showerhead having a capacitance that varies with the gap; measurement circuitry coupled to the controller and to the plurality of capacitive plates, the measurement circuitry measuring a capacitance relative to each capacitive plate and provide indications thereof to the controller; wherein the controller provides an indication relative to the shape of the gap based, at least in part, upon the measured capacitances; and wherein at least one capacitive plate is used to measure two different capacitances while resting on the platen.