Method for plasma treatment of a carbon layer

Abstract

A method of treating a carbon layer depositited in or on a substrate, such as a silicon wafer is provided. At least one aliphatic organic compound chosen from the group of an aliphatic alkanes, aliphatic alkenes and aliphatic alkines is utilized as a precursor for plasma treatment of the carbon layer.

1 . A method for the plasma treatment of at least one carbon layer in or on a substrate for the production of a semiconductor device, comprising: 
 generating a plasma with at least one precursor selected from a group comprising an aliphatic alkane, aliphatic alkene and aliphatic alkine; and    exposing the at least one carbon layer to the plasma during an etching process.    
   
   
       2 . The method of  claim 1 , wherein the precursor comprises at least one of: CH 4 , C 2 H 4  and C 2 H 2 .  
   
   
       3 . The method of  claim 1 , wherein the plasma comprises at least one of: Oxygen radicals and Nitrogen radicals.  
   
   
       4 . The method of  claim 1 , wherein: 
 the plasma comprises O 2 ; and    the ratio between the O 2  and the at least one precursor is approximately 1:1.    
   
   
       5 . The method of  claim 4 , wherein: 
 the at least one precursor comprises CH 4 ; and    the ratio between the O 2  and CH 4  is approximately 1:1.    
   
   
       6 . The method of  claim 1 , wherein generating the plasma comprises: 
 flowing methane at a rate of approximately 40 sccm;    flowing oxygen at a rate of approximately 40 sccm; and    flowing nitrogen at a rate of approximately 120 sccm.    
   
   
       7 . The method according to  claim 1 , wherein the plasma is at a pressure of approximately 10 to 100 mTorr at some time during the etching process.  
   
   
       8 . The method according to  claim 7 , wherein the plasma is at a pressure of approximately 40 mTorr at some time during the etching process.  
   
   
       9 . The method of  claim 1 , wherein: 
 high frequency power of the plasma is approximately 500 Watts; and    low frequency of the power of the plasma is approximately 150 Watts.    
   
   
       10 . The method of  claim 1 , wherein an etch rate and an etch profile is tunable by adjusting the ratio of oxygen in the plasma.  
   
   
       11 . A method of fabricating a semiconductor device, comprising: 
 depositing a layer of carbon on a substrate;    generating a plasma with at least one precursor selected from a group comprising an aliphatic alkane, aliphatic alkene and aliphatic alkine; and    forming one or more structures in the layer of carbon by exposing the layer of carbon to the plasma.    
   
   
       12 . The method of  claim 11 , wherein the layer of carbon comprises a layer of amorphous carbon.  
   
   
       13 . The method of  claim 11 , wherein the semiconductor device is a memory device.  
   
   
       14 . The method of  claim 13 , wherein the memory device is a dynamic random access memory (DRAM) device.  
   
   
       15 . The method of  claim 11 , wherein the precursor comprises at least one of: CH 4 , C 2 H 4  and C 2 H 2 .  
   
   
       16 . The method of  claim 11 , wherein: 
 the plasma comprises O 2 ; and    the ratio between the O 2  and the at least one precursor is approximately 1:1.    
   
   
       17 . The method of  claim 6 , wherein: 
 the at least one precursor comprises CH 4 ; and    the ratio between the O 2  and CH 4  is approximately 1:1.    
   
   
       18 . A method of forming a structure in a carbon layer of a semiconductor device, comprising: 
 generating a plasma with at least one precursor selected from a group comprising an aliphatic alkane, aliphatic alkene and aliphatic alkine; and    forming the structure in the layer of carbon by exposing the layer of carbon to the plasma.    
   
   
       19 . The method of  claim 18 , wherein: 
 the plasma comprises O 2 ; and    the ratio between the O 2  and the at least one precursor is approximately 1:1 to form the structure with substantially straight sidewalls.    
   
   
       20 . The method of  claim 18 , wherein: 
 the plasma comprises O 2 ; and    the at least one precursor comprises CH 4 , wherein CH 4  flow rate is in excess of the O 2  flow rate causing carbon deposition on the sidewalls to form the structure with tapered sidewalls.