Scanning exposure method

Abstract

A step-and-scan exposure method and a scanning exposure apparatus in which a mask has a plurality of patterns and the number of patterns to be transferred to each shot area of a photosensitive substrate varies. The scanning and stepping movements are controlled in accordance with the number of patterns transferred, and dimensions of a pattern illumination area are varied in accordance with the patterns to be transferred. Transfer of a pattern to a shot area is omitted when an image of the pattern on the shot area would extend beyond the photosensitive substrate. Elimination of exposure scanning movements for patterns that are not to be transferred permits rapid movements of the mask and the substrate to scanning start positions.

What is claimed is:  
     
       1. A step-and-scan exposure method in which a photo-sensitive substrate and a mask having first and second patterns arranged sequentially in a mask scanning direction are scanned synchronously to expose an image of one or both of said patterns on each of a plurality of shot areas of said photosensitive substrate, comprising: 
       a step (a) in which, in synchronism with scanning of said mask in said mask scanning direction by an amount corresponding to a first dimension of said first pattern in said mask scanning direction, said photosensitive substrate is scanned by an amount corresponding to said first dimension, said first pattern being illuminated in the course of said mask scanning in step (a);  
       a step (b) in which, in synchronism with scanning of said mask in said mask scanning direction by an amount corresponding to a second dimension of both of said first and second patterns in said mask scanning direction, said photosensitive substrate is scanned by an amount corresponding to the second dimension, each of said patterns being illuminated in the course of said mask scanning in step (b); and  
       wherein step (a) is preferred for some shot areas and step (b) is performed for other shot areas.  
     
     
       2. A step-and-scan exposure method according to  claim 1 , wherein step (a) is performed when an image of said second pattern on a shot area would extend beyond the photosensitive substrate. 
     
     
       3. A step-and-scan exposure method according to  claim 1 , wherein step (a) is performed after step (b). 
     
     
       4. A step-and-scan exposure method according to  claim 1 , further comprising a step (c) in which, after said photosensitive substrate is exposed to an image of said first pattern in step (a), said mask is moved in said mask scanning direction by an amount corresponding to a dimension of said second pattern in said mask scanning direction, without illuminating said second pattern. 
     
     
       5. A step-and-scan exposure method according to  claim 4 , wherein in step (c) said mask is moved at a maximum speed to a scanning start position. 
     
     
       6. A step-and-scan exposure method according to  claim 4 , wherein during step (c), said photosensitive substrate is moved at a maximum speed to a scanning start position for a next shot area. 
     
     
       7. A step-and-scan exposure method according to  claim 1 , wherein, when steps (b) and (a) are to be performed in that order for respective shot areas, step (b) is performed and then said mask is moved, without illuminating said mask, to a scanning start position and step (a) is performed. 
     
     
       8. A step-and-scan exposure method according to  claim 7 , wherein said mask is moved to said scanning start position at a maximum speed. 
     
     
       9. A step-and-scan exposure method in which a photo-sensitive substrate and a mask having first and second patterns arranged sequentially in a direction perpendicular to a mask scanning direction are scanned synchronously to illuminate one or both of said patterns and to expose an image of one or both of said patterns on each of a plurality of shot areas of said photosensitive substrate, comprising: 
       a step (a) in which, in synchronism with scanning of said mask in said mask scanning direction, while said first pattern is illuminated and said second pattern is not illuminated, said photosensitive substrate is scanned in a substrate scanning direction;  
       a step (b) in which said photosensitive substrate is moved in a direction perpendicular to said substrate scanning direction by a distance less than a dimension of an image of both of said first and second patterns in said direction perpendicular to said substrate scanning direction; and  
       a step (c) in which, in synchronism with scanning of said mask in said mask scanning direction, while said first and second patterns are illuminated, said photosensitive substrate is scanned in said substrate scanning direction.  
     
     
       10. A step-and-scan exposure method according to  claim 9 , wherein step (a) is performed when an image of said second pattern would extend beyond a shot area of said photosensitive substrate. 
     
     
       11. A step-and-scan exposure method according to  claim 9 , wherein steps (c), (b), and (a) are performed in that order. 
     
     
       12. A step-and-scan exposure method in which patterns on a mask are transferred to shot areas on a photosensitive substrate by a series of scanning exposures, in each of which a mask, having a plurality of patterns arranged sequentially in a mask scanning direction, is moved in said mask scanning direction relative to a pattern illumination area, and a substrate is moved in a substrate scanning direction synchronously with the movement of the mask, wherein the number of said patterns to be transferred to different shot areas varies, and the extent of movements of said mask and said substrate for each scanning exposure is varied in accordance with the number of patterns to be transferred in each scanning exposure. 
     
     
       13. A step-and-scan exposure method according to  claim 12 , wherein a dimension of said illumination area in the mask scanning direction is varied so that when a pattern is not to be transferred to a shot area that pattern is not illuminated. 
     
     
       14. A step-and-scan exposure method according to  claim 12 , wherein a scanning start position of the mask relative to the pattern illumination area for each scanning exposure is controlled in accordance with the number of patterns to be transferred in that scanning exposure. 
     
     
       15. A step-and-scan exposure method according to  claim 12 , wherein after each scanning exposure, the mask and the substrate are moved to scanning start positions for a next scanning exposure, and wherein the movements of the mask and the substrate to the scanning start positions are performed at speeds substantially higher than the speeds at which the mask and the substrate are moved, respectively, during a scanning exposure. 
     
     
       16. A step-and-scan exposure method in which patterns on a mask are transferred to shot areas on a photosensitive substrate by a series of scanning exposures, in each of which a mask, having a plurality of patterns arranged sequentially in a direction transverse to a mask scanning direction, is moved in said mask scanning direction relative to a pattern illumination area, and a substrate is moved in a substrate scanning direction synchronously with the movement of the mask, and in which the number of said patterns to be transferred to different shot areas varies, comprising: 
       for each scanning exposure, overlapping a shot area with an image region containing images of one or more said patterns;  
       varying the amount of overlapping in accordance with the number of patterns to be transferred to each shot area; and  
       controlling the size of the illuminating area during each scanning exposure so that only patterns to be transferred are illuminated.  
     
     
       17. A step-and-scan exposure method according to  claim 16 , wherein, after each scanning exposure, the substrate is stepped to overlap a next shot area with said image region, and wherein the extent of stepping is varied in accordance with the amount of overlapping in the scanning exposure of the preceding shot area. 
     
     
       18. A step- and - scan exposure method in which each of a plurality of shot areas on a substrate is exposed through a mask having patterns, comprising:    
         a step  ( a )  in which, in synchronism with movement of the mask along a direction in which the patterns are arranged relative to an energy beam, the substrate is moved by a first distance to expose a first shot area with the energy beam; and    
         a step  ( b )  in which, in synchronism with movement of the mask along the direction relative to the energy beam, the substrate is moved by a second distance different from the first distance to expose a second shot area different from the first shot area with the energy beam.   
     
     
       19. A method according to  claim 18 , wherein said substrate is of a circular shape and one of said first and second shot areas is disposed close to the periphery of the substrate while the other of said first and second areas is disposed further from the periphery than said one of the shot areas. 
     
     
       20. A method according to  claim 18 , wherein at least one of said patterns is transferred onto said first shot area, and at least one of said patterns is transferred onto said second shot area, wherein the number of the patterns transferred onto said second shot area is different from the number of the patterns transferred onto said first shot area. 
     
     
       21. A step- and - scan exposure method in which each of a plurality of shot areas on a substrate is exposed through a mask, comprising:    
         a step  ( a )  in which, in synchronism with movement of the mask relative to an energy beam, the substrate is moved by a first distance to expose a first shot area with the energy beam; and    
         a step  ( b )  in which, in synchronism with movement of the mask relative to the energy beam, the substrate is moved by a second distance different from the first distance to expose a second shot area different from the first shot area with the energy beam.   
     
     
       22. A step- and - scan exposure method in which a pattern on a mask is transferred onto each of a plurality of shot areas on a substrate by a series of scanning exposures, the mask is moved relative to an energy beam and the substrate is moved in synchronism with the movement of the mask in each scanning exposure, wherein distances by which the substrate is moved in scanning exposures of different shot areas are varied in accordance with a shot layout on the substrate.   
     
     
       23. A step- and - scan exposure method in which each of a plurality of shot areas on a substrate is exposed with an energy beam, comprising:    
         a step  ( a )  in which, the substrate is moved by a first distance, between scanning exposures of a first shot area and a second shot area adjacent to the first shot area, in a non - scanning direction perpendicular to a scanning direction in which the substrate is moved in each scanning exposure; and    
         a step  ( b )  in which, the substrate is moved by a second distance different from the first distance in the non - scanning direction between scanning exposure of the second shot area and a third shot area adjacent to the second shot area.   
     
     
       24. A method according to  claim 23 , wherein said substrate is moved in synchronism with movement of said mask in each scanning exposure, and said mask is moved in a direction perpendicular to a direction in which patterns on said mask are arranged. 
     
     
       25. A method for manufacturing devices including a process of transferring a device pattern onto a workpiece using the method according to  claim 21 . 
     
     
       26. A scanning exposure apparatus which exposes each of a plurality of shot areas on a substrate through a projection optical system, with an energy beam irradiated on a mask, comprising: 
       
         a mask stage disposed at an object side of said projection optical system;  
       
       
         a substrate stage disposed at an image side of said projection optical system;  
       
       
         a driving system connected to said mask stage and said substrate stage to move said substrate in synchronism with the movement of said mask upon scanning exposure of each of said shot areas; and  
       
       
         a controller connected to said driving system to control an operation of said scanning exposure in accordance with a shot layout on said substrate. 
       
     
     
       27. An apparatus according to  claim 26 , wherein said controller varies a distance by which said substrate is moved during the scanning exposure among the different shot areas. 
     
     
       28. An apparatus according to  claim 26 , wherein said controller functions such that the operation of the scanning exposure performed for a first shot area which is disposed close to the periphery of the substrate is different from the operation of the scanning exposure performed for a second shot area which is disposed further from the periphery than said first shot area. 
     
     
       29. A scanning exposure method comprising: 
       
         exposing each of a plurality of shot areas on a substrate with an energy beam irradiated on a mask by movement of the mask and the substrate relative to the energy beam for each shot area; and  
       
       
         changing a condition in a scanning exposure of the substrate with the energy beam in accordance with positions of the shot areas in the substrate, the condition being related to scanning distance of the substrate for the scanning exposure. 
       
     
     
       30. A method according to  claim 29 , wherein said condition is changed in scanning exposures of different shot areas of said plurality of shot areas. 
     
     
       31. A method according to  claim 30 , wherein said different shot areas includes at least one of shot area disposed close to the periphery of said substrate. 
     
     
       32. A method according to  claim 29 , further comprising: 
       
         moving said substrate, between scanning exposures of said plurality of shot areas with said energy beam, in a direction crossing a scanning direction in which said substrate is moved for each scanning exposure.