Heat treatment apparatus

Abstract

A support table holds a working fluid in an inner space thereof, and has four cylindrical heaters arranged to surround a cooling plate disposed centrally of the support table. In time of heating, vapor generated from each cylindrical heater spreads toward a central region and peripheral regions of the support table (as schematically shown in two-dot chain line arrows). The vapor can reach peripheral ends, without flows of the vapor colliding with one another, in a way to suppress generation of stagnation points. Since the support table can be heated uniformly, a substrate is heat-treated uniformly over the entire surface thereof. The support table is cooled efficiently by the cooling plate disposed centrally of the support table.

1 . A heat treatment apparatus for heat-treating substrates, comprising: 
 a support table for supporting the substrates and holding a working fluid inside;    a cooling device disposed centrally of said support table in plan view for cooling said support table; and    a heating device disposed to surround said cooling device for heating said working fluid.    
     
     
         2 . An apparatus as defined in  claim 1 , wherein said heating device includes at least n (n being an integer 3 or more) cylindrical heaters, said cylindrical heaters being arranged to form sides of an n-sided polygon centering on said cooling device.  
     
     
         3 . An apparatus as defined in  claim 2 , wherein each of said cylindrical heaters forms a side of a triangle or rectangle.  
     
     
         4 . An apparatus as defined in  claim 2 , wherein said support table defines therein a common working fluid chamber for storing said working fluid and accommodating all of said cylindrical heaters.  
     
     
         5 . An apparatus as defined in  claim 2 , wherein said support table defines therein a plurality of separate working fluid chambers for storing said working fluid and accommodating said cylindrical heaters.  
     
     
         6 . An apparatus as defined in  claim 1 , wherein said heating device is a planar heater.  
     
     
         7 . An apparatus as defined in  claim 6 , wherein said planar heater has a ringlike shape surrounding said cooling device.  
     
     
         8 . An apparatus as defined in  claim 7 , wherein said planar heater has an annular shape surrounding said cooling device.  
     
     
         9 . An apparatus as defined in  claim 6 , wherein said planar heater has an outer circumference thereof extending to edges of said support table.  
     
     
         10 . An apparatus as defined in  claim 6 , wherein said support table defines therein a working fluid chamber for storing said working fluid, said planar heater being disposed on a lower surface of said support table corresponding to a bottom of said working fluid chamber.  
     
     
         11 . An apparatus as defined in  claim 10 , wherein said working fluid chamber has a ringlike shape surrounding said cooling device.  
     
     
         12 . An apparatus as defined in  claim 6 , wherein said planar heater comprises one of a mica heater and a silicone rubber heater.  
     
     
         13 . An apparatus as defined in  claim 1 , wherein said cooling device comprises a cooling plate defining a cooling water channel.  
     
     
         14 . An apparatus as defined in  claim 1 , further comprising a control device for operating said heating device and said cooling device to control temperature of an upper surface of said support table.  
     
     
         15 . An apparatus as defined in  claim 14 , further comprising a temperature sensor for detecting the temperature of said upper surface of said support table, said control device being operable based on detection results received from said temperature sensor.  
     
     
         16 . An apparatus as defined in  claim 14 , wherein: 
 said heating device comprises an electric heater;    said heat treatment apparatus further comprising:    a power source electrically connected to said heating device; and    a switch disposed between said heating device and said power source;    said control device being arranged to operate said switch.    
     
     
         17 . An apparatus as defined in  claim 14 , wherein: 
 said cooling device comprises a heat exchanger using cooling water;    said heat treatment apparatus further comprising:    a cooling water source communicating with said cooling device; and    an electromagnetic switch valve disposed between said cooling device and said cooling water source;    said control device being arranged to operate said electromagnetic switch valve.    
     
     
         18 . An apparatus as defined in  claim 1 , wherein said support table includes a support device projecting from an upper surface thereof for contacting and supporting the substrates.  
     
     
         19 . An apparatus as defined in  claim 18 , wherein said support device comprises small balls.  
     
     
         20 . An apparatus as defined in  claim 18 , wherein said support device comprises ceramics.