Mask set for measuring an overlapping error and method of measuring an overlapping error using the same

Abstract

A mask set for measuring an overlapping error according to the invention comprises a first mask consisted of a mask substrate on which a plurality of unit patterns are formed: The plurality of unit patterns are arranged in radial shape round a given center. The mask set of the present invention further comprises a second mask consisted of a mask substrate on which a plurality of unit patterns are formed. The plurality of unit patterns of the second mask are arranged in same shape as the plurality of unit patterns of the first mask, whereby when the first and second masks are overlapped to each other, the unit pattern of the first mark and the neighboring unit pattern of the second mask maintains a certain angle.

1 . A mask set for measuring an overlapping error, comprising: 
 a first mask consisted of a mask substrate on which a plurality of unit patterns are formed, said plurality of unit patterns arranged in radial shape round a given center;    a second mask consisted of a mask substrate on which a plurality of unit patterns are formed, said plurality of unit patterns arranged in same shape as said plurality of unit patterns of said first mask, whereby when said first and second masks are overlapped to each other, said unit pattern of said first mark and the neighboring unit pattern of said second mask maintains a certain angle.    
     
     
         2 . The mask set of  claim 1 , said some one unit pattern and neighboring unit pattern of said unit pattern of the said first mask maintains an angle of between 0° and 90°.  
     
     
         3 . The mask set of  claim 1 , said some on unit pattern of said first mark and the neighboring unit pattern of said second mask maintains an angle of between 0° and 45°.  
     
     
         4 . The mask set of  claim 1 , said unit patterns are dark patterns.  
     
     
         5 . The mask set of  claim 1 , said unit patterns are clear patterns.  
     
     
         6 . The mask set of  claim 1 , said each unit pattern of said first mask and said each unit pattern of the second mask have a measuring guide, respectively, whereby the first and second measuring patterns formed by said first and second masks can be easily distinguished.  
     
     
         7 . The mask set of  claim 6 , said each measuring guide formed on said each unit pattern of said first mask and each measuring guide formed on said each unit pattern of said second mask are located at opposite portions, whereby said each measuring guide formed on said each unit pattern of said first mask and said each measuring guide formed on said unit pattern of said second mask are faced each other.  
     
     
         8 . A method of measuring an overlapping error, comprising the steps of: 
 forming first measuring patterns on a wafer using a first mask on which a plurality of unit patterns are arranged in radial shape round a given center;    forming overlapping second measuring patterns on said wafer using a second mask on which a plurality of unit patterns are arranged in same shape as said plurality of unit patterns of said first mask, whereby said first measuring patterns formed by said first mask and said second measuring patterns formed by said second mask maintains a certain angle;    identifying an overlapping error between said first measuring patterns and said second measuring patterns;    calculating a value of the overlapping error using the equations  1  and  2       Δ x=Δr ·tan θ 2    [equation 1] Δ x=Δr ·tan θ 2    [equation 2]   wherein; Δx and Δy are actual value of overlapping error    Δr is a distance from a central point to a cross point of said first and second measuring patterns; and    θ 2  is a deviation angle of the first and second measuring patterns.    
     
     
         9 . The method of  claim 8 , said some one unit pattern and neighboring unit pattern of said unit pattern of the said first mask maintains an angle of between 0° and 90°.  
     
     
         10 . The method of  claim 8 , said some on unit pattern of said first mark and the neighboring unit pattern of said second mask maintains an angle of between 0° and 45°.  
     
     
         11 . The method  claim 8 , said unit patterns are dark patterns.  
     
     
         12 . The method  claim 8 , said unit patterns are clear patterns.  
     
     
         13 . The method  claim 8 , said each unit pattern of said first mask and said each unit pattern of the second mask have a measuring guide, respectively, whereby the first and second measuring patterns formed by said first and second masks can be easily distinguished.  
     
     
         14 . The method of  claim 13 , said each measuring guide formed on said each unit pattern of said first mask and each measuring guide formed on said each unit pattern of said second mask are located at opposite portions, whereby said each measuring guide formed on said each unit pattern of said first mask and said each measuring guide formed on said unit pattern of said second mask are faced each other.