Ceramic substrate

Abstract

An object of the present invention is to provide a ceramic substrate that is superior in temperature rising/dropping characteristics and breakdown voltage at a high temperature, has a small warp amount, and is best as a substrate for semiconductor- producing/examining devices. The ceramic substrate of the present invention is a ceramic substrate having a conductor formed on the surface thereof or inside thereof, characterized in that said ceramic substrate is having 15×10 11 or less pores which have a diameter of 0.5 μm or more per m 2 .

1 . (Canceled).  
   
   
       2 . A ceramic heater comprising a ceramic substrate and a temperature control means, 
 wherein the number of pores with a diameter of 0.5 μm or more obtained from surface measurement of said ceramic substrate with a microscope is 15×10 11  per m 2  or less.    
   
   
       3 . The ceramic heater according to  claim 2 , 
 wherein said temperature control means is a resistance heating element equipped on the surface of said ceramic substrate or inside of said ceramic substrate.    
   
   
       4 . The ceramic heater according to  claim 2 , 
 wherein said temperature control means is a Peltier device equipped on the surface of said ceramic substrate.    
   
   
       5 . The ceramic heater according to  claim 2 , 
 wherein an electrostatic electrode is embedded in said ceramic substrate.    
   
   
       6 . The ceramic heater according to  claim 2 , 
 wherein a chuck top conductor layer is formed on the surface of said ceramic substrate.    
   
   
       7 . The ceramic heater according to  claim 2 , 
 wherein said ceramic substrate is an oxide ceramic.    
   
   
       8 . The ceramic heater according to  claim 2 , 
 wherein said ceramic substrate is a non-oxide ceramic containing oxygen.    
   
   
       9 . The ceramic heater according to  claim 2 , 
 wherein said ceramic substrate is a non-oxide ceramic containing 0.05% to 10% by weight of oxygen.    
   
   
       10 . The ceramic heater according to  claim 2 , 
 wherein said ceramic substrate contains carbon.    
   
   
       11 . The ceramic heater according to  claim 2 , 
 wherein said ceramic substrate comprises aluminum nitride.    
   
   
       12 . The ceramic heater according to  claim 2 , 
 wherein the number of pores with a diameter of 0.5 μm or more obtained from surface measurement of said ceramic substrate with a microscope is 1×10 8  to 5×10 10  per m 2 .    
   
   
       13 . A ceramic heater comprising a ceramic substrate having a heating element inside thereof or on the surface thereof, 
 wherein said ceramic substrate comprises nitride ceramic and    the number of pores with a diameter of 0.5 μm or more obtained from surface measurement of said ceramic substrate with a microscope is 15×10 11  per m 2  or less.    
   
   
       14 . The ceramic heater according to  claim 13 , 
 wherein said ceramic heater is capable of use at a temperature of 200° C. or higher.    
   
   
       15 . The ceramic heater according to  claim 13 , 
 wherein said ceramic substrate has a thickness of 25 mm or less.    
   
   
       16 . The ceramic heater according to  claim 13 , 
 wherein said ceramic substrate has a diameter exceeding 200 mm.    
   
   
       17 . The ceramic heater according to  claim 13 , 
 wherein said ceramic substrate contains 0.1 to 20 weight % of sintering aid.    
   
   
       18 . An electrostatic chuck comprising a ceramic substrate and a temperature control means, 
 wherein the number of pores with a diameter of 0.5 μm or more obtained from surface measurement of said ceramic substrate with a microscope is 15×10 11  per m 2  or less.    
   
   
       19 . The electrostatic chuck according to  claim 18 , 
 wherein the number of pores with a diameter of 0.5 μm or more obtained from surface measurement of said ceramic substrate with a microscope is 1×10 8  per m 2  or more.