Method of plasma etching of high-K dielectric materials with high selectivity to underlying layers

Abstract

A method of etching high dielectric constant materials using halogen gas and reducing gas chemistry. An embodiment of the method is accomplished using a 20 to 300 sccm of chlorine and 2 to 200 sccm of carbon monoxide, regulated to a total chamber pressure of 2-100 mTorr to etch a hafnium oxide layer.

What is claimed is:  
     
         1 . A method of plasma etching, comprising: 
 introducing into an etch chamber a substrate having a layer of dielectric material is at least one of HfO2, ZrO2, ZrSiO2, HfSiO2, and TaO2;    providing into the etch chamber a process gas comprising carbon monoxide and a halogen containing gas; and    exposing the layer of dielectric material to a plasma formed from the process gas.    
     
     
         2 . The method of  claim 1  wherein the halogen containing gas comprises a chlorine containing gas.  
     
     
         3 . The method of  claim 1  wherein halogen gas comprises chlorine.  
     
     
         4 . The method of  claim 3  wherein said chlorine containing gas is Cl2.  
     
     
         5 . The method of  claim 4  wherein said providing step further comprises the step of: 
 supplying 20 to 300 sccm of Cl2 and 2 to 200 sccm of CO.  
 
     
     
         6 . The method of  claim 1  further comprising: 
 maintaining a gas pressure of between 2-100 mTorr.  
 
     
     
         7 . The method of  claim 5  further comprising the step of: 
 maintaining a gas pressure of 4 mTorr.  
 
     
     
         8 . The method of  claim 1  further comprising: 
 applying a bias power to a cathode electrode of 5 to 100 W.  
 
     
     
         9 . The method of  claim 6  further comprising: 
 applying a bias power to a cathode electrode of 20 W.  
 
     
     
         10 . The method of  claim 1  further comprising: 
 applying an inductive source power to an inductively coupled antenna of 200 to 2500 W.  
 
     
     
         11 . The method of  claim 5  further comprising: 
 applying an inductive source power to an inductively coupled antenna of 1100 W.  
 
     
     
         12 . A method of plasma processing, comprising: 
 introducing into an process chamber a substrate having a layer of hafnium oxide (HfO2);    introducing into the process chamber a process gas comprising carbon monoxide and a halogen containing gas; and    exposing the layer of hafnium oxide (HfO2) to a plasma formed from the process gas.    
     
     
         13 . The method of  claim 12  further comprising the step of: 
 maintaining the substrate at a temperature between 100 to 500 degrees Celsius.  
 
     
     
         14 . The method of  claim 12  further comprising the step of: 
 maintaining the substrate at a temperature of 350 degrees Celsius.  
 
     
     
         15 . The method of  claim 12  wherein the halogen containing gas comprises chlorine.  
     
     
         16 . The method of  claim 12  wherein the halogen containing gas is hydrogen chlorine.  
     
     
         17 . A method of plasma processing, comprising: 
 introducing into the process chamber a process gas comprising carbon monoxide and a halogen containing gas; and    exposing a substrate, disposed in the process chamber and having at least partially exposed material containing hafnium, to a plasma formed from the process gas.    
     
     
         18 . The method of  claim 17  wherein the halogen containing gas comprises chlorine.  
     
     
         19 . The method of  claim 17  wherein said introducing step further comprises: 
 supplying 20 to 300 sccm of Cl2 and 2 to 200 sccm of CO.  
 
     
     
         20 . A method for plasma etching: 
 supplying between 20 to 300 sccm of chlorine and between 2 to 200 sccm of carbon monoxide to a process chamber having a substrate disposed therein, the substrate having at least partial exposed of halfium containing material;    maintaining a gas pressure of between 2-100 mTorr; applying a bias power to a cathode electrode of between 5 to 100 W;    applying power to an inductively coupled antenna of between 200 to 2500 W to produce a plasma containing said chlorine gas and said carbon monoxide gas; and    maintaining said workpiece at a temperature between 100 and 500 degrees Celsius.