Charged-Particle-Beam Processing Using a Cluster Source

Abstract

A cluster source is used to assist charged particle beam processing. For example, a protective layer is applied using a cluster source and a precursor gas. The large mass of the cluster and the low energy per atom or molecule in the cluster restricts damage to within a few nanometers of the surface. Fullerenes or clusters of fullerenes, bismuth, gold or Xe can be used with a precursor gas to deposit material onto a surface, or can be used with an etchant gas to etch the surface. Clusters can also be used to deposit material directly onto the surface to form a protective layer for charged particle beam processing or to provide energy to activate an etchant gas.

We claim as follows: 
     
         1 . A method of charged-particle beam processing, comprising:
 positioning a work piece in a vacuum chamber;   directing an etchant precursor gas toward a work piece, wherein the gas adsorbs to the surface of the work piece; and   directing a beam of charged clusters toward the work piece, the beam depositing energy into the region of interest to induce an etching chemical reaction of the adsorbed etchant precursor gas at the region of interest.   
     
     
         2 . The method of  claim 1  in which directing a beam of clusters of atoms or molecules toward a region of interest comprises directing a beam of clusters of inert atoms or molecules. 
     
     
         3 . The method of  claim 1  in which directing a beam of clusters of atoms or molecules toward a region of interest comprises directing a beam of clusters of non-reactive atoms or molecules. 
     
     
         4 . The method of  claim 1  in which directing a beam of clusters of atoms or molecules toward a region of interest on the work piece includes directing a beam of clusters including carbon, gold, bismuth, or xenon. 
     
     
         5 . The method of  claim 1  in which directing a beam of clusters of atoms or molecules toward a region of interest on the work piece includes directing a beam of clusters including C 60 , C 70 , C 80 , C 84 , Au 3 , Bi 3 , or Xe 40 . 
     
     
         6 . The method of  claim 1  in which directing a beam of clusters of atoms or molecules toward a region of interest on the work piece includes directing a beam of clusters having an average of greater than 100 components per cluster. 
     
     
         7 . The method of  claim 1  in which the gas comprises XeF 2 , F 2 , Cl 2 , Br 2 , I 2 , a fluorocarbon, trifluoro acetamide, trifluoroacetic acid, trichloroacetic acid, water, ammonia, or oxygen. 
     
     
         8 . The method of  claim 1  further comprising directing a charged particle beam from a non-cluster source toward the etched region of the work piece in the vacuum chamber. 
     
     
         9 . The method of  claim 1  in which directing a beam of clusters of atoms or molecules toward a region of interest on the work piece includes directing a beam of clusters from a plasma ion source. 
     
     
         10 . A method of charged-particle beam processing, comprising:
 positioning a work piece in a vacuum chamber;   providing an etchant precursor gas at the work piece surface; and   directing a beam of clusters of atoms or molecules toward a region of interest on the work piece, the etchant precursor gas reacting in the presence of the beam of clusters to etch the work piece surface.   
     
     
         11 . The method of  claim 10  in which directing a beam of clusters of atoms or molecules toward a region of interest on the work piece includes directing a beam of clusters of inert atoms or molecules. 
     
     
         12 . The method of  claim 10  in which directing a beam of clusters of atoms or molecules toward a region of interest on the work piece includes directing a beam of clusters of non-reactive atoms or molecules. 
     
     
         13 . The method of  claim 10  in which directing a beam of clusters of atoms or molecules toward a region of interest on the work piece includes directing a beam of clusters from an evaporative cluster source. 
     
     
         14 . The method of  claim 10  in which directing a beam of clusters of atoms or molecules toward a region of interest on the work piece includes directing a beam of clusters including carbon, gold, bismuth, or xenon. 
     
     
         15 . The method of  claim 10  in which directing a beam of clusters of atoms or molecules toward a region of interest on the work piece includes directing a beam of clusters from a plasma ion source. 
     
     
         16 . A charged-particle beam system, comprising:
 a vacuum chamber;   a charged particle beam column for directing a beam of focused, non-clustered particles toward a work piece in the vacuum chamber for processing the work piece;   a work piece support for supporting a work piece within the vacuum chamber;   a cluster ion source, for directing a primary beam of charged clusters toward the work piece within the vacuum chamber; and   a gas injection system for providing an etchant gas in the vicinity of the region of interest on the work piece, the etchant gas being adsorbed onto the surface and undergoing a chemical reaction only in the presence of the beam of charged clusters.   
     
     
         17 . The charged-particle beam system in  claim 16  in which the cluster ion source includes a plasma ion source. 
     
     
         18 . The charged-particle beam system in  claim 17  in which the plasma ion source includes an inductively coupled plasma ion source. 
     
     
         19 . The charged-particle beam system in  claim 16  in which the cluster ion source includes a source of clusters of fullerenes. 
     
     
         20 . The charged-particle beam system in  claim 16  in which the cluster ion source includes a source of clusters of bismuth, gold, or xenon.