Ceramic heater

Abstract

An object of the present invention is to provide a heater wherein even if a through hole into which lifter pins and the like for supporting a semiconductor wafer will be inserted is made, the temperature in the vicinity of the through hole is not lowered so that the temperature in its heating face is even. The present invention is a ceramic heater comprising a ceramic substrate; and a resistance heating element formed on the surface of the ceramic substrate or inside above-mentioned ceramic substrate, above-mentioned ceramic substrate being equipped with a through hole, wherein the wall face of above-mentioned through hole has a surface roughness of Rmax=0.05 to 200 μm based on JIS B 0601.

1 . A ceramic heater comprising: a ceramic substrate; and a resistance heating element formed on the surface of said ceramic substrate or inside said ceramic substrate, said ceramic substrate being equipped with a through hole, 
 wherein the wall face of said through hole has a surface roughness of Rmax=0.05 to 200 μm based on JIS B 0601.    
     
     
         2 . The ceramic heater according to  claim 1 , 
 wherein said ceramic substrate is in a disc-shape.    
     
     
         3 . The ceramic heater according to  claim 1  or  2 , 
 wherein said ceramic substrate is a carbide ceramic or a nitride ceramic.  
 
     
     
         4 . The ceramic heater according to  claim 1  or  2 , 
 wherein the thickness of said ceramic substrate is 50 mm or less.