Method for cleaning substrate surface

Abstract

There is provided a surface cleaning apparatus and method using plasma to remove a native oxide layer, a chemical oxide layer, and a damaged portion from a silicon substrate surface, and contaminants from a metal surface. A mixture of H 2 and N 2 gas is used as a first processing gas. By absorbing potential in a grounded grid or baffle between a plasma generator and a substrate, only radicals are passed to the substrate, and HF gas is used as a second processing gas. Thus a native oxide layer, a chemical oxide layer, or a damaged portion formed on the silicon substrate during etching is removed in annealing step with H 2 flow. The environment of a chamber is maintained constant by introducing a conditioning gas after each wafer process. Therefore, process repeatability is improved.

1 - 22 . (canceled)  
   
   
       23 . A method for cleaning native oxides, chemical oxides or damaged portions thereon off a surface of a substrate using plasma, the method comprising the steps in sequence of: 
 A. introducing a first processing gas which is a mixture of H 2  and N 2  gas into a first inlet of a cleaning apparatus;    B. generating and maintaining a plasma of said first processing gas in a plasma generating space in said cleaning apparatus.    C. adding a second processing gas of HF gas into a second inlet in said cleaning apparatus in which said second gas is activated to HF radicals by said plasma of first gas;    D. forming a polymer layer of NxHyFz that is a by-product of said first gas, said second gas and said materials on said surface of said substrate; and    E. removing said polymer layer by annealing said substrate to clean said surface of said substrate.    
   
   
       24 . The method of  claim 23 , wherein H 2  is used as an annealing gas in step E.  
   
   
       25 . The method of  claim 23 , wherein said H 2  gas is introduced in step A at a flow rate of above 20 sccm, said N 2  gas is introduced in step A at a flow rate of above 500 sccm, and said plasma is generated using Microwave power in the range of 100 W to 2000 W.  
   
   
       26 . The method of  claim 25 , wherein said HF gas is introduced in step C at a flow rate of 5 sccm to 500 sccm.  
   
   
       27 . The method of  claim 23 , wherein gas pressure of said first processing gas is maintained in a range of 0.1 Torr to 50 Torr.  
   
   
       28 . The method of  claim 23 , wherein said annealing is performed using a UV lamp or IR lamp.  
   
   
       29 . The method of  claim 23 , wherein a gas pressure of 0.1 Torr to 50 Torr is maintained in step A.  
   
   
       30 . The method of  claim 23 , wherein a wall temperature of said cleaning apparatus is maintained at between 50° C. and 120° C.  
   
   
       31 . The method of  claim 23 , wherein H 2 , N 2  or Ar is used as an annealing gas in step E.  
   
   
       32 . The method of  claim 23 , wherein said annealing step E is performed with a flow of H 2  gas at 10 sccm and 5,000 sccm at a temperature between 120° C. and 400° C.  
   
   
       33 . A surface cleaning method using plasma for removing a native oxide layer formed on a semiconductor substrate during an etching process in which a contact hole is formed in a semiconductor substrate having at least one layer including an insulation layer, the method comprising the steps in sequence of: 
 A. generating a plasma from a first processing gas which is a mixture of H 2  and N 2 ;    B. introducing HF gas into said plasma;    C. contacting said semiconductor substrate with said plasma from step B whereby to form a polymer layer of NxHyFz on said insulation layer and said native oxide layer formed on said substrate; and    D. removing said polymer layer and said natural oxide layer by annealing wherein components of said polymer layer are decomposed and combined with the components of said natural oxide layer and removed.    
   
   
       34 . The method of  claim 33 , wherein said annealing step D is performed using H 2 , N 2  or Ar as an annealing gas.  
   
   
       35 . The method of  claim 33 , wherein said annealing step D is performed with a flow of H 2  at 10 sccm and 5,000 sccm at temperature between 120° C. and 400° C.  
   
   
       36 . The method of  claim 33 , wherein said method is performed in a cleaning apparatus in which a wall thereof is maintained at a temperature of between 50° C. and 120° C.  
   
   
       37 . A surface cleaning method for cleaning native oxides off a surface of a silicon substrate wafers used for fabrication of an integrated circuit in a surface cleaning apparatus having a chamber that can be maintained in a vacuum state, a substrate mount for mounting said silicon substrate, a first processing gas inlet for introducing a first processing gas into the apparatus, a plasma generator, a filter for passing only radicals to the substrate, a second processing gas inlet for introducing a second processing gas into the apparatus, and a third processing gas inlet for introducing a third processing gas into the apparatus to maintain the environment of the chamber constant after processing each wafer, the method comprising the steps in sequence of: 
 A. introducing a first processing gas of a mixture of H 2  and N 2  into said chamber via said first processing gas inlet;    B. forming plasma of said first processing gas using the plasma generator;    C. introducing a second processing gas of HF into said chamber via said second processing gas inlet;    D. forming on said surface of said substrate a polymer layer of NxHyFz that is a by-product of said first gas, said second gas and materials of a surface of said substrate;    E. removing said polymer layer and said natural oxide layer by annealing wherein components of said polymer layer are decomposed and combined with components of said natural oxide layer and removed; and    F. introducing said third processing gas into said chamber to maintain the environment of said chamber.    
   
   
       38 . The method of  claim 37 , wherein said H 2  gas is introduced in step A at a flow rate above 20 sccm, said N 2  gas is introduced in step A at a flow rate above 500 sccm, said plasma as generated in step B using Microwave power in the range of 100 W to 2000 W, said HF is introduced in step C at a flow rate of 5 sccm to 500 sccm.  
   
   
       39 . The method of  claim 37 , wherein said polymer layer and said natural oxide layer are removed by annealing using a UV lamp or IR lamp.  
   
   
       40 . The method of  claim 37 , further comprising a step E 1  of removing a damaged portion of the surface of said substrate after said step E of removing said polymer layer and said natural oxide layer by annealing with a flow of H 2 .  
   
   
       41 . The method of  claim 37 , wherein a wall temperature of said chamber is maintained at between 50° C. and 120° C.