Metal heater

Abstract

The present invention aims to provide a metal heater that hardly causes dispersion in the temperature of a semiconductor wafer or the like upon heating, and heats it quickly without causing warping and sagging in its metal plate. The present invention provides a metal heater which includes metal plates and a heating element, wherein the number of said metal plates is a plural number, the heating element is sandwiched between the metal plates, and the thickness of a metal plate on a heating face side is the same as or larger than the thickness of a metal plate on a side opposite to said heating face side.

1 . A metal heater comprising a metal plate and a heating element, 
 wherein    the number of said metal plates is a plural number,    said heating element is sandwiched between said metal plates, and    the thickness of a metal plate on a heating face side is the same as or larger than the thickness of a metal plate on a side opposite to said heating face side.    
   
   
       2 . The metal heater according to  claim 1 , 
 wherein    said heating element is divided into two or more portions.    
   
   
       3 . A metal heater comprising a plurality of metal plates and a heating element, said heating element sandwiched between said metal plates, 
 wherein    said plurality of metal plates are made of the same material.    
   
   
       4 . The metal heater according to  claim 3 , 
 wherein    said plurality of metal plates comprises a copper-aluminum alloy.    
   
   
       5 . A metal heater comprising a plurality of metal plates and a heating element, with said heating element sandwiched between said metal plates, 
 wherein    a convex portion for supporting an object to be heated is placed on a heating face opposing the object to be heated, of said metal plate corresponding to an area on which said heating element is formed.    
   
   
       6 . The metal heater according to  claim 5 , 
 wherein    the area on which said heating element is formed has a diameter of 250 mm or more, and the number of convex portions is 6 or more.    
   
   
       7 . The metal heater according to  claim 5 , 
 wherein    the area on which said heating element is formed has a diameter of 200 to 250 mm, and the number of said convex portions is 5 or more.    
   
   
       8 . The metal heater according to any of  claims 5  to  7 , 
 wherein    said heating element is divided into two or more portions.