Patent ID: 11953448
Assignee: TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY LTD.
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 7:
8. A method for defect inspection, comprising:
receiving a photomask having a surface and a plurality of patterns disposed on the surface;
obtaining a gray scale image of the photomask using a scanner of a lithography system;
defining a defect region in the gray scale image, using a computing system of the lithography system, wherein the defect region has a plurality of first regions, and each of the first regions has a gray scale value and a difference between the gray scale value and a gray scale reference;
performing a calculation to obtain a score in order to improve an inspection for a complicated defect by the computing system of the lithography system; and
determining the photomask to have the complicated defect or to be free of the complicated defect according to the score obtained from the calculation, wherein the calculation is performed according to an equation (2):, W
          s
        
        =
        
          
            
              Σ
              ⁢
              
                
                
                  
                    (
                    
                      G
                      ×
                      
                        e
                        1
                      
                    
                    )
                  
                  
                    G
                    ⁢
                    
                      
                    
                    ⁢
                    1
                  
                
                
              
            
            +
            
              Σ
              ⁢
              
                
                
                  
                    (
                    
                      G
                      ×
                      
                        e
                        2
                      
                    
                    )
                  
                  
                    G
                    ⁢
                    
                      
                    
                    ⁢
                    2
                  
                
                
              
            
            +
            
              Σ
              ⁢
              
                
                
                  
                    (
                    
                      G
                      ×
                      
                        e
                        3
                      
                    
                    )
                  
                  
                    G
                    ⁢
                    
                      
                    
                    ⁢
                    3
                  
                
                
              
            
            +
            …
          
          
            Σ
            ⁢
            
              
                
                G
                
              
              
                
                  G
                  ⁢
                  
                    
                  
                  ⁢
                  1
                
                ,
                
                  G
                  ⁢
                  
                    
                  
                  ⁢
                  2
                
                ,
                
                  G
                  ⁢
                  
                    
                  
                  ⁢
                  3
                  ⁢
                  …
                
              
            
          
        
      
    
    
      
        (
        2
        )
      
    
  

wherein Ws is the score, G is an individual difference of a region in a first group G1, a second group G2, a third group G3 and an Nth group GN, e1 is a first weighting factor, e2 is a second weighting factor, and en is an Nth weighting factor; and
performing an exposure operation using the photomask when the photomask is determined to be free of the complicated defect, or removing the photomask from the exposure operation when the photomask is determined to have the complicated defect.