Patent ID: 7804306
Filing Date: 2010-09-28
Classification: G01B,G01D

Abstract:
1. A non-contact sensor for sensing a distance between a platen and a conductive showerhead of a semiconductor processing chamber, the sensor comprising: a housing resting on the platen; 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 forming capacitors, each having a capacitance that corresponds to a distance between the platen and the conductive showerhead; measurement circuitry coupled to the controller and the plurality of capacitive plates, the measurement circuitry applying excitation voltages of substantially equal magnitude, but opposite polarity to the plurality of capacitive plates, measuring the capacitance of each capacitor and providing an indication thereof to the controller; and wherein the controller provides a distance and parallelism indication relative to the platen and conductive showerhead based at least in part upon the measured capacitances.