Method and apparatus for repairing an alternating phase shift mask

Abstract

A method and apparatus for correcting phase shift defects in a photomask is provided by scanning the photomask for the defect and determining locations of at least one defect. Following the determination of the location of a defect, the defect is three-dimensionally analyzed producing three-dimensional results. Utilizing the three-dimensional results, a focus ion beam (FIB) is directed onto the defect to eliminate the defect. The FIB is controlled by an etch map which is generated based on the three-dimensional results. To provide further precision to the repairing of the photomask, test patterns of the FIB are generated and three-dimensionally analyzed. The three-dimensional test pattern results are further utilized in generating the etch map to provide greater control to the FIB.

What is claimed is:  
     
         1 . A method for repairing phase shift defects in a phase shift photomask, comprising: 
 analyzing at least one phase shift defect in the phase shift photomask in three-dimensions producing three-dimensional results;    directing an actinic radiation beam onto the phase shift defect; and    controlling the actinic radiation beam directed onto the phase shift defect based on the three-dimensional results obtained in the step of analyzing the phase shift defect.    
     
     
         2 . The method for correcting defects in a phase shift photomask as claimed in  claim 1 , further comprising: 
 exposing the phase shift photomask to Halogen gas during the step of directing an actinic radiation beam and the step of controlling the actinic radiation beam.    
     
     
         3 . The method for correcting defects in a phase shift photomask as claimed in  claim 1 , wherein: 
 the step of controlling the actinic radiation beam including controlling the actinic radiation beam based on actinic radiation beam parameters.    
     
     
         4 . The method for correcting defects in a phase shift photomask as claimed in  claim 3 , wherein: 
 the step of controlling the actinic radiation beam based on the actinic radiation beam parameters including: 
 generating at least one actinic radiation beam test pattern;  
 three-dimensionally analyzing the test pattern producing three-dimensional test pattern results; and  
 determining the actinic radiation beam parameters from the test pattern results.  
   
     
     
         5 . The method for correcting defects in a phase shift photomask as claimed in  claim 3 , wherein: 
 the step of controlling the actinic radiation beam including generating an etch map.    
     
     
         6 . A method for correcting defects in a photomask, comprising: 
 scanning the photomask for the defect;    determining a location of at least one defect;    three-dimensionally analyzing the defect producing three-dimensional results; and    directing a focus ion beam (FIB) onto the defect eliminating the defect.    
     
     
         7 . The method of correcting a defect in the photomask as claimed in  claim 6 , wherein: 
 the step of directing the FIB onto the defect further including: 
 controlling the FIB according to the three-dimensional results obtained in the step of three-dimensionally analyzing the defect.  
   
     
     
         8 . The method of correcting a defect in the photomask as claimed in  claim 7 , further comprising: 
 generating an etch map based on the three-dimensional results prior to the step of directing the FIB onto the defect.    
     
     
         9 . The method of correcting a defect in the photomask as claimed in  claim 8 , wherein: 
 the step of generating an etch map including generating the etch map based on FIB parameters.    
     
     
         10 . The method of correcting a defect in the photomask as claimed in  claim 6 , further comprising: 
 determining the FIB parameters prior to the step of directing actinic radiation onto the defect.    
     
     
         11 . The method of correcting a defect in the photomask as claimed in  claim 10 , wherein: 
 the step of determining the FIB parameters including: 
 sputtering at least one test pattern; and  
 measuring the test pattern.  
   
     
     
         12 . The method of correcting a defect in the photomask as claimed in  claim 11 , wherein: 
 the step of measuring the test pattern including three-dimensionally measuring the test pattern.    
     
     
         13 . The method of correcting a defect in the photomask as claimed in  claim 12 , wherein: 
 the step of measuring the test pattern including utilizing an atomic force microscope (AFM) to measure the test pattern.    
     
     
         14 . The method of correcting a defect in the photomask as claimed in  claim 12 , wherein: 
 the step of measuring the test pattern including utilizing a profilometer to measure the test pattern.    
     
     
         15 . The method of correcting a defect in the photomask as claimed in  claim 6 , wherein: 
 the step of three-dimensionally analyzing the defect including utilizing an AFM in performing the three-dimensional analysis.    
     
     
         16 . The method of correcting a defect in the photomask as claimed in  claim 6 , wherein: 
 the step of three-dimensionally analyzing the defect including utilizing a profilometer in performing the three-dimensional analysis.    
     
     
         17 . The method of correcting a defect in the photomask as claimed in  claim 6 , wherein: 
 the step of directing the FIB onto the defect including calculating an exposure duration and beam intensity.    
     
     
         18 . The method of correcting a defect in the photomask as claimed in  claim 6 , further comprising: 
 repositioning the mask such that a second defect is positioned under the FIB; and    directing the FIB onto the second defect eliminating the second defect.    
     
     
         19 . An apparatus for repairing phase shift defects on a photomask, comprising: 
 a means for analyzing the photomask for defects coupled to a memory such that defect location on the mask is stored in memory;    a means for three-dimensionally analyzing the defect coupled to the memory to store three-dimensional results of the three-dimensional analyzes;    a processor means coupled to the memory, the means for analyzing, the means for three-dimensionally analyzing and a means for correcting the defect such that the processor controls the means for analyzing, the means for three-dimensionally analyzing and the means for correcting based on the defect location and the three-dimensional results; and    the means for correcting the defect coupled to the processor to receive control instructions to eliminate the defect.    
     
     
         20 . The apparatus for repairing phase shift defects as claimed in  claim 19 , further comprising: 
 a means for generating test patterns coupled to the processor such that the processor controls the means for generating test patterns.