Patent ID: 8221580
Filing Date: 2012-07-17
Classification: F25B,H01J,H01L,H05H

Abstract:
1. A plasma reactor, comprising: a reactor chamber and an electrostatic chuck having a surface for holding a workpiece inside said chamber, wherein said chamber is configured to enable processing of said workpiece while held on said surface of said electrostatic chuck, wherein said electrostatic chuck comprises: an insulating puck layer having a top surface for receiving a wafer; a conductive base layer supporting said insulating puck, an ESC electrode buried in said insulating puck layer; a bias power feed conductor extending axially through said base and puck layers of said electrostatic chuck and having a top end connected to a feed point of said ESC electrode and a bottom end coupled to an RF plasma bias power generator; and a dielectric sleeve surrounding said bias power feed conductor; a backside gas pressure source coupled to said electrostatic chuck for applying a thermally conductive gas under a selected pressure into a workpiece-surface interface formed whenever a workpiece is held on said surface; an evaporator inside said electrostatic chuck and a refrigeration loop having an expansion valve for controlling flow of coolant through said evaporator; a chuck temperature sensor in said electrostatic chuck; a workpiece temperature sensor at said surface of said electrostatic chuck configured to measure a temperature of said workpiece; a thermal model coupled to receive inputs from both of said workpiece and chuck temperature sensors and configured to simulate heat transfer between said evaporator and said surface of said electrostatic chuck based upon contemporaneous measurements during processing of said workpiece from said chuck temperature sensor and said workpiece temperature sensor; an agile control processor coupled to said thermal model and governing said backside gas pressure source coupled to said electrostatic chuck, said agile control processor governing said backside gas pressure source in response to predictions from said model of changes in said selected pressure that would bring the temperature measured by said workpiece temperature sensor closer to a desired temperature.