Apparatus and method for wafer planarization

Abstract

An apparatus and a method for wafer planarization is disclosed. A disclosed apparatus comprises a liquid nitrogen supply tube; a nitrogen gas transfer tube linked to the nitrogen gas supply tank by valve; an etchant supply tube linked with the nitrogen gas transfer tube; a spray nozzle part linked with the nitrogen gas supply tube; and a chamber with a spray nozzle attached to the upper part of the chamber and a wafer rotating equipment placed in the lower part. A disclosed apparatus and a method has advantage to planarize an entire surface of wafer by spraying high pressure of etchant vapor into a wafer surface rotating at high speed.

1 . An apparatus for wafer planarization comprising: 
 a liquid nitrogen supply tank;    a nitrogen gas transfer tube linked with the liquid nitrogen supply tank by a valve;    an etchant supply tube linked with the nitrogen gas transfer tube;    an etchant supply tank for containing etchant linked with the etchant supply tube; and    a chamber with a spray nozzle part linked with the nitrogen gas transfer tube attached to the upper part thereof and a wafer rotating equipment placed in the lower part thereof.    
   
   
       2 . The apparatus as defined by  claim 1 , wherein a sensor to detect the remaining volume of the etchant is attached to the etchant supply tank.  
   
   
       3 . The apparatus as defined by  claim 1 , wherein the exit of the etchant supply tube comprises a nozzle.  
   
   
       4 . The apparatus as defined by  claim 1 , wherein the spray nozzle part comprises plural nozzles.  
   
   
       5 . The apparatus as defined by  claim 1 , wherein the wafer rotating equipment comprises: 
 a rotation actuator with a motor;    a lift for loading and unloading a wafer at the upper part of the rotation actuator;    a wafer stage at the upper part of the lift on which the wafer is positioned;    a clamp at the upper edge of the stage to fix the wafer; and    a cleaning nozzle to supply de-ionized water to the wafer.    
   
   
       6 . A method for wafer planarization comprising: 
 emitting nitrogen gas to a nitrogen gas transfer tube;    mixing the emitted nitrogen gas and etchant;    planarizing a wafer by spraying the mixed etchant from a spray nozzle part linked with the nitrogen gas transfer tube onto the entire surface of the wafer; and    cleaning the wafer.    
   
   
       7 . The method as defined by  claim 6 , wherein the nitrogen gas is emitted at high pressure from a liquid nitrogen supply tank into the nitrogen gas transfer tube.  
   
   
       8 . The method as defined by  claim 6 , wherein mixing the emitted nitrogen gas and the etchant comprises: 
 rising of the etchant, which is stored and, diluted with de-ionized water in an etchant supply tank, by pressure difference between the nitrogen gas transfer tube at low pressure and an etchant supply tube at high pressure linked with the nitrogen gas transfer tube and the etchant supply tank; and    mixing fine particles of the etchant sprayed through a nozzle at the end of the etchant supply tube with the emitted nitrogen gas.    
   
   
       9 . The method as defined by  claim 6 , wherein planarizing the wafer comprises: 
 transforming the etchant sprayed from the spray nozzle part into vapor by means of the nitrogen at high pressure;    spraying uniformly the etchant in vapor onto the entire surface of the wafer rotating at high speed; and    etching anisotropically the wafer in the same direction as that of the wafer rotation.