Method for patterning hfo2-containing dielectric

Abstract

A wafer has a trench, a STI layer formed in the trench, an HfO2-containing gate dielectric covering the wafer and the STI layer, a gate electrode formed on the HfO2-containing gate dielectric, and at least a spacer formed beside the gate electrode. An ion bombardment utilizing Ar, He, O2, CHF3 or mixture thereof is performed to convert the exposed HfO2-containing gate dielectric to an intergraded layer, and a wet chemical is utilized to remove the intergraded layer.

1 . A method for patterning an HfO2-containing gate dielectric, the method comprising: 
 providing a wafer having a trench, a STI layer formed in the trench, the HfO2-containing gate dielectric covering the wafer and the STI layer, a gate electrode formed on the HfO2-containing gate dielectric, and at least a spacer formed beside the gate electrode;    performing an ion bombardment with Ar, He, O2, CHF3or mixture thereof to convert the exposed HfO2-containing gate dielectric to an intergraded layer having a higher etching selectivity than HfO2; and    utilizing a wet chemical to remove the intergraded layer.    
   
   
       2 . The method of  claim 1  wherein the STI layer comprises SiO2.  
   
   
       3 . The method of  claim 1  wherein the spacer comprises SiO2.  
   
   
       4 . The method of  claim 1  wherein the gate electrode comprises TaN or TiN.  
   
   
       5 . The method of  claim 1  wherein the method comprises utilizing a nitrogen gas or a nitrogen-contained gas to perform the ion bombardment.  
   
   
       6 . The method of  claim 1  wherein the intergraded layer is removed at temperature between 50° C. and 300° C.  
   
   
       7 . A method for etching an HfO2-containing dielectric, the method comprising: 
 providing a wafer having the HfO2-containing dielectric;    performing an ion bombardment with Ar, He, O2, CHF3or mixture thereof to convert portions of the HfO2-containing dielectric to an intergraded layer; and    utilizing a wet chemical to remove the intergraded layer.    
   
   
       8 . The method of  claim 7  wherein the method comprises utilizing a nitrogen gas or a nitrogen-contained gas to perform the ion bombardment.  
   
   
       9 . The method of  claim 7  wherein the intergraded layer is removed at temperature between 50° C. and 300° C.