Wafer processing apparatus, wafer stage, and wafer processing method

Abstract

A heater function and an electrostatic chuck function are incorporated in a ceramic plate for placing a wafer, and the ceramic plate is fixed to a cooling jacket with ceramic bolts having a low coefficient of thermal conductivity with an intervening heat insulating member. In order to transmit heat input in the wafer to the water-cooling jacket with high repeatability, a heat-conducting member having elasticity in the vertical direction is sandwiched between the ceramic plate and the cooling jacket. The degradation of temperature distribution of wafers due to the radiant heat radiation from the sidewall of the ceramic plate to the chamber can be minimized by covering the circumference of the ceramic plate with a radiation insulator.

What is claimed is:  
     
         1 . A wafer stage for supporting semiconductor wafers comprising an internal electrode for impressing a direct-current voltage and a radio-frequency voltage and a ceramic plate incorporating a heater wiring fixed with bolts to a cooling jacket whose inside is cooled with a cooling medium, wherein said ceramic plate is vacuum-insulated from said cooling jacket, and heat transfer between said ceramic plate and said cooling jacket is performed by radiant heat transmission.  
     
     
         2 . A wafer stage for supporting semiconductor wafers comprising an internal electrode for impressing a direct-current voltage and a radio-frequency voltage and a ceramic plate incorporating a heater wiring fixed with bolts to a cooling jacket whose inside is cooled with a cooling medium, wherein a heat-conducting member having elasticity in the vertical direction is inserted between said ceramic plate and said cooling jacket so that both ends of said heat-conducting member contact said ceramic plate and said cooling jacket, and heat transfer between said ceramic plate and said cooling jacket is performed by radiant heat transmission and the heat conduction of said heat-conducting member.  
     
     
         3 . A wafer processing apparatus for the plasma treatment of semiconductor wafers having a wafer stage for supporting semiconductor wafers comprising an internal electrode for impressing a direct-current voltage and a radio-frequency voltage and a ceramic plate incorporating a heater wiring fixed with bolts to a cooling jacket whose inside is cooled with a cooling medium, wherein said ceramic plate is vacuum-insulated from said cooling jacket, the temperature of the member of said wafer processing apparatus facing said ceramic plate is controlled with a temperature control means, and said ceramic plate is cooled by heat transfer by radiant heat transmission to said cooling jacket and said member.  
     
     
         4 . A wafer processing apparatus for the plasma treatment of semiconductor wafers having a wafer stage for supporting semiconductor wafers comprising an internal electrode for impressing a direct-current voltage and a radio-frequency voltage and a ceramic plate incorporating a heater wiring fixed with bolts to a cooling jacket whose inside is cooled with a cooling medium, wherein a heat-conducting member having elasticity in the vertical direction is inserted between said ceramic plate and said cooling jacket so that both ends of said heat-conducting member contact said ceramic plate and said cooling jacket, the temperature of the member of said wafer processing apparatus facing said ceramic plate is controlled with a temperature control means, and said ceramic plate is cooled by radiant heat transmission and heat conduction to said cooling jacket and heat transfer by radiant heat transmission to said member.  
     
     
         5 . A wafer stage or a wafer processing apparatus according to  claims 1  to  4 , wherein at least three heat insulating members of a constant height are inserted between said ceramic plate and said cooling jacket.  
     
     
         6 . A wafer processing method wherein the temperature of said ceramic plate according to  claims 1  to  4  is controlled by controlling at least one of electric power supplied to said heater, the temperature of said member, the temperature of said cooling medium, or the flow rate of said cooling medium.  
     
     
         7 . The wafer stage or wafer processing apparatus according to  claims 1  to  4 , wherein a black paint is applied onto the surface of said cooling jacket.  
     
     
         8 . The wafer stage or wafer processing apparatus according to  claims 1  to  4 , wherein an irregularity is formed on onto the surface of said cooling jacket.  
     
     
         9 . The wafer stage or wafer processing apparatus according to claims  2  or  4 , wherein the material of said heat-conducting member is a stainless steel or Inconel.  
     
     
         10 . The wafer stage or wafer processing apparatus according to claims  2  or  4 , wherein the number of said heat-conducting member can be adjusted.