Mask, exposure method, line width measuring method, and method for manufacturing semiconductor devices

Abstract

An exposure method includes an exposure step and a measurement step. The exposure step transfers a circuit pattern of a mask onto a photosensitive substrate via an optical system. The mask includes a circuit pattern and an inspection pattern to be used for a measurement of a line width of the pattern transferred to the substrate. The measurement step measures, prior to the exposure step, using the inspection pattern which is formed on the mask to be used in the exposure step, a line width of the pattern to be transferred to the substrate.

1 - 6 . (canceled)  
     
     
         7 . An exposure method comprising: 
 transferring a first measurement pattern to a substrate via an optical system;    transferring a second measurement pattern by superimposing the second measurement pattern on an image of the first measurement pattern which has been transferred to the substrate via the optical system; and    transferring an extraction pattern to extract a predetermined pattern image from a superimposed image formed by superimposing the image of the first measurement pattern and an image of the second measurement pattern on the substrate to the superimposed image via the optical system.    
     
     
         8 . An exposure method according to  claim 7 , further comprising measuring a line width of the extracted pattern image.  
     
     
         9 . An exposure method according to  claim 8 , further comprising adjusting exposure conditions of the substrate based on the line width of the extracted pattern image.  
     
     
         10 . An exposure method according to  claim 7 , wherein the first measurement pattern, the second measurement pattern, and the extraction pattern are formed on a mask on which a circuit pattern is formed.  
     
     
         11 . An exposure method according to  claim 10 , wherein: 
 the first measurement pattern and the second measurement pattern each comprise a plurality of linear patterns which are parallel to each other; and    the extraction pattern is formed in a shape to extract at least one approximately rhombic-shaped image from the superimposed image of the first measurement pattern and the second measurement pattern.    
     
     
         12 . An exposure method according to  claim 7 , wherein the second measurement pattern is a pattern in which the first measurement pattern has been rotated by a predetermined angle.  
     
     
         13 . An exposure method according to  claim 12 , wherein the first measurement pattern is a part of a circuit pattern formed on a mask.  
     
     
         14 . An exposure method according to  claim 13 , wherein a line width of the first measurement pattern corresponds to a line width of the circuit pattern.  
     
     
         15 . An exposure method comprising: 
 transferring a first line-and-space pattern to be formed at a predetermined line width to a substrate via an optical system; and    transferring a second line-and-space pattern to be formed at a line width which is different from the predetermined line width at a predetermined angle with respect to the first line-and-space pattern to an image of the first line-and-space pattern which has been transferred to the substrate via the optical system.    
     
     
         16 . An exposure method according to  claim 15 , further comprising measuring a line width of a superimposed pattern image formed by superimposing the image of the first line-and-space pattern and an image of the second line-and-space pattern.  
     
     
         17 . An exposure method according to  claim 16 , wherein the first line-and-space pattern is rotated by the predetermined angle, and the rotated first line-and-space pattern is transferred to the substrate as the second line-and-space pattern.  
     
     
         18 . An exposure method according to  claim 16 , wherein the line width of the first line-and-space pattern corresponds to a line width of a circuit pattern.  
     
     
         19 . A line width measurement method comprising: 
 transferring a first measurement pattern to a substrate via an optical system;    transferring a second measurement pattern by superimposing the second measurement pattern on an image of the first measurement pattern which has been transferred to the substrate via the optical system;    transferring an extraction pattern to extract a predetermined pattern image from a superimposed image formed by superimposing the image of the first measurement pattern and an image of the second measurement pattern on the substrate to the superimposed image via the optical system; and    measuring a line width of the extracted pattern image.    
     
     
         20 . A line width measurement method according to  claim 19 , further comprising determining exposure conditions of the substrate based on the line width of the extracted pattern image.  
     
     
         21 . A line width measurement method comprising: 
 transferring a first line-and-space pattern to be formed at a predetermined line width to a substrate via an optical system;    transferring a second line-and-space pattern to be formed at a line width which is different from the predetermined line width at a predetermined angle with respect to the first line-and-space pattern to an image of the first line-and-space pattern which has been transferred to the substrate via the optical system; and    measuring a line width of a superimposed pattern image formed by superimposing the image of the first line-and-space pattern and an image of the second line-and-space pattern.    
     
     
         22 . A line width measurement method according to  claim 21 , further comprising determining exposure conditions of the substrate based on the line width of the superimposed pattern image.