Method and system to enhance the removal of high-k dielectric materials

Abstract

A method and system are disclosed for modifying a layer of high-k material using a plasma process. The plasma process leads to enhanced removal rates of the modified high-k dielectric material using wet etching. The plasma process modifies the layer of high-k material through exposure to the plasma, where the plasma can comprise inert gases and/or reactive gases. The plasma treatment can be implemented as a step performed at the end of a gate-electrode etch process, or as a step at the end of a spacer-etch process.

What is claimed is:  
     
         1 . A method of processing a layer containing a high-permittivity material in a plasma processing system, the method comprising: 
 providing a layer containing a high-permittivity material overlying a substrate;    modifying the layer containing the high-permittivity material by exposing the layer to a plasma; and    wet etching to remove the modified layer containing the high-permittivity material.    
     
     
         2 . The method as claimed in  claim 1 , wherein the modifying partially removes the layer containing the high-permittivity material.  
     
     
         3 . The method as claimed in  claim 1 , wherein the modifying partially disassociates the layer containing the high-permittivity material.  
     
     
         4 . The method according to  claim 1 , wherein the modifying comprises introducing a process gas into a plasma chamber and creating the plasma, the process gas comprising a reactive gas.  
     
     
         5 . The method according to  claim 4 , wherein the reactive gas comprises at least one of HBr and HCl.  
     
     
         6 . The method according to  claim 4 , wherein the process gas further comprises an inert gas.  
     
     
         7 . The method according to  claim 6 , wherein the inert gas is selected from He, Ne, Ar, Kr, Xe, or mixtures thereof.  
     
     
         8 . The method according to  claim 1 , wherein the modifying comprises introducing a process gas into a plasma chamber and creating the plasma, the process gas comprising an inert gas.  
     
     
         9 . The method according to  claim 8 , wherein the inert gas is selected from He, Ne, Ar, Kr, Xe, or mixtures thereof.  
     
     
         10 . The method according to  claim 1 , wherein the high-permittivity material comprises at least one of Ta 2 O 5 , TiO 2 , ZrO 2 , Al 2 O 3 , HfSiO, and HfO 2 .  
     
     
         11 . The method according to  claim 1 , wherein the modifying further comprises RF powering a substrate holder that exposes the substrate containing the high-permittivity material to the plasma.  
     
     
         12 . The method according to  claim 1 , wherein the modifying further comprises grounding a substrate holder that exposes the substrate containing the high-permittivity material to the plasma.  
     
     
         13 . The method according to  claim 1 , wherein the modifying further comprises applying a DC bias to a substrate holder that exposes the substrate containing the high-permittivity material to the plasma.  
     
     
         14 . The method according to  claim 1 , wherein the modifying further comprises electrically isolating a substrate holder from the plasma processing system, the substrate holder exposing the substrate containing the high-permittivity material to the plasma.  
     
     
         15 . A method of processing a layer containing a high-permittivity material in a plasma processing system, the method comprising: 
 providing a layer containing a high-permittivity material overlying a substrate;    introducing a process gas into a plasma processing chamber and creating a plasma;    modifying the layer containing the high-permittivity material by exposing the layer to the plasma; and    removing the modified layer containing the high-permittivity material using wet etching.    
     
     
         16 . A method of processing a layer containing a high-permittivity material in a plasma processing system, the method comprising: 
 providing a layer containing a high-permittivity material overlying a substrate;    introducing a process gas into a plasma processing chamber and creating a plasma;    anisotropically modifying the layer containing the high-permittivity material in accordance with a pattern by exposing the layer to the plasma; and    removing the layer containing a high-permittivity material using wet etching.    
     
     
         17 . A plasma processing system comprising: 
 a process chamber capable of sustaining a plasma;    a gas injection system configured to inject a process gas into the process chamber;    a plasma source configured to create plasma from said process gas;    a substrate holder that exposes a substrate comprising a layer of high-permittivity materials to the plasma, thereby modifying the layer;    a controller that controls the plasma processing system; and    a wet cleaning chamber disposed in or operatively coupled to said process chamber.    
     
     
         18 . The system according to  claim 17 , wherein the plasma source comprises an inductive coil.  
     
     
         19 . The system according to  claim 17 , wherein the plasma source comprises a plate electrode.  
     
     
         20 . The system according to  claim 17 , wherein the plasma source comprises an antenna.  
     
     
         21 . The system according to  claim 17 , wherein the plasma source comprises an ECR source.  
     
     
         22 . The system according to  claim 17 , wherein the plasma source comprises a Helicon wave source.  
     
     
         23 . The system according to  claim 17 , wherein the plasma source comprises a surface wave source.  
     
     
         24 . The system according to  claim 17 , wherein the process gas comprises a reactive gas.  
     
     
         25 . The system according to  claim 24 , wherein the reactive gas comprises at least one of HBr and HCl.  
     
     
         26 . The system according to  claim 24 , wherein the process gas further comprises an inert gas.  
     
     
         27 . The system according to  claim 26 , wherein the inert gas is selected from He, Ne, Ar, Kr, Xe, or mixtures thereof.  
     
     
         28 . The system according to  claim 17 , wherein the process gas comprises an inert gas.  
     
     
         29 . The system according to  claim 28 , wherein the inert gas is selected from He, Ne, Ar, Kr, Xe, or mixtures thereof.  
     
     
         30 . The system according to  claim 17 , wherein the high-permittivity material comprises at least one of Ta 2 O 5 , TiO 2 , ZrO 2 , Al 2 O 3 , HfSiO, and HfO 2 .  
     
     
         31 . The system according to  claim 17 , wherein said wet cleaning chamber is operatively coupled to said process chamber.  
     
     
         32 . The system according to  claim 17 , wherein said wet cleaning chamber is disposed in said process chamber.  
     
     
         33 . The system according to  claim 17 , wherein the substrate holder is RF powered.  
     
     
         34 . The system according to  claim 17 , wherein the substrate holder is grounded.  
     
     
         35 . The system according to  claim 17 , wherein a DC bias is applied to the substrate holder.  
     
     
         36 . The system according to  claim 17 , wherein the substrate holder is electrically isolated from the plasma processing system.