Patent ID: 6406545
Filing Date: 2002-06-18
Classification: H01L

Abstract:
A wafer processing apparatus comprising:a processing chamber; a plate arranged in said processing chamber for supporting a wafer; an RF power supply source connected to said plate, for supplying an RF power to said plate to generate a plasma on the wafer; a DC power supply source connected to said plate, for supplying a DC power to said plate to hold the wafer on said plate; a pedestal spaced apart from said plate; a thermal medium passage disposed in said pedestal for circulating one of a cooling medium and a heating medium and for transferring thermal energy between said pedestal and said one of said mediums; a first gas delivery mechanism for providing a first gas layer between said plate and said wafer; a second gas delivery mechanism for providing a second gas layer in the space between said pedestal and said plate; a first pressure controller for controlling a pressure of the first gas layer; a second pressure controller for controlling a pressure of the second gas layer; and, a control circuit for controlling said first pressure controller to control the pressure of the first gas layer such that the first gas layer is at a pressure in a pressure range in which a thermal conductivity of the first gas layer is substantially constant with respect to changes in pressure of the first gas layer and for controlling said second pressure controller to control the pressure of the second gas layer such that the second gas layer is at a pressure in a pressure range in which a thermal conductivity of the second gas layer changes with respect to changes in pressure of the second gas layer for controlling an amount of heat transferred to/from said pedestal.