Lithographic apparatus, device manufacturing method, and method of correcting a mask

Abstract

A lithographic apparatus includes a mask correction system configured to controllably and locally alter a property of a mask, for example transmissivity, transmissivity to a particular polarization state, birefringence and/or geometry. The mask correction system, in an embodiment, directs a beam of radiation onto a spot of the mask, the mask being scanned relative to the mask correction system. The mask correction system may include an arrangement to irradiate multiple spots on the mask substantially simultaneously.

The invention claimed is: 
     
       1. A lithographic apparatus, comprising:
 a mask support configured to support structure having a body, the body having a surface that, in use, supports a mask bearing a pattern and to position the mask in a first radiation beam so as to impart the pattern to the first radiation beam; 
 a projection optical system configured to project that receives, in use, the first radiation beam patterned by the mask and has one or more refractive and/or reflective elements to direct the first radiation beam onto a substrate; and 
 a mask correction system configured to controllably and locally deform material constituting part of, or alter a materials property within, the integral physical structure of the mask for use of the mask having the locally deformed material or altered property in patterning of the first radiation beam, wherein the mask correction system comprises a focusing optical system configured to directone or more optical elements that receive, in use, a second radiation beam different from the first radiation beam and direct the second radiation beam to the maskso that the property of the mask is locally altered by the second radiation beam; and 
 a non-transitory computer program product comprising instructions, that when executed by one or more computers, cause setting of one or more properties of the second radiation beam to enable the second radiation beam to controllably and locally alter a geometry of material constituting part of, or controllably and locally alter a materials property within, a portion of the integral physical structure of the mask to respectively a desired altered geometry or desired altered materials property for use in incidence of the first radiation onto that portion of the mask having the locally altered geometry or altered materials property in patterning of the first radiation beam. 
 
     
     
       2. The lithographic apparatus of  claim 1 , wherein the mask correction system is configured to second radiation beam, when it is incident on the mask, locally alter alters one or more properties of the mask selected from the group consisting of: transmissivity to the first radiation beam; transmissivity to a polarization state of the first radiation beam; birefringence; and geometry. 
     
     
       3. The lithographic apparatus of  claim 1 , wherein the mask correction system is configured to one or more optical elements, in use direct second radiation onto a plurality of spots on the mask substantially simultaneously. 
     
     
       4. The lithographic apparatus of  claim 3 , wherein further comprising an actuator connected to the mask support comprises a positioner configured structure to scan the mask relative to the mask correction system second radiation directed to the mask in a first direction. 
     
     
       5. The lithographic apparatus of  claim 4 , wherein the positioner is further configured to scan actuator, in use, scans the mask in the first direction when the mask is positioned in the first radiation beam. 
     
     
       6. The lithographic apparatus of  claim 3 , wherein the plurality of spots are arranged in a two-dimensional array, at least either rows or columns of the two-dimensional array of spots forming an acute angle to the first direction. 
     
     
       7. The lithographic apparatus of  claim 3 , wherein the focusing optical system comprises one or more optical elements comprise:
 a beam divideran optical element to divide the second radiation beam into a plurality of sub-beams to be incident on the mask at respective spaced apart spots; and 
 a beam directoran optical element to selectively direct each of the sub-beams to respective spots on the mask. 
 
     
     
       8. The lithographic apparatus of  claim 7 , wherein the beam divider optical element to divide the second radiation beam comprises a microlens array and the beam director optical element to selectivity direct each of the sub-beams comprises an array of movable mirrors, each microlens of the microlens array being arranged to focus a sub-beam on a respective one of the movable mirrors. 
     
     
       9. The lithographic apparatus of  claim 8 , wherein each movable mirror is movable between a first position at which a respective one of the sub-beams is directed to be incident on a respective spot on the mask and a second position at which the respective one of the sub-beams is directed to not be incident on the mask. 
     
     
       10. The lithographic apparatus of  claim 8 , wherein each movable mirror is movable between a plurality of positions at each of which a respective one of the sub-beams is directed to be incident on a respective spot on the mask. 
     
     
       11. The lithographic apparatus of  claim 1 , wherein the focusing optical system comprises further comprising a radiation source configured laser to provide the second radiation beam. 
     
     
       12. The lithographic apparatus of  claim 1 , wherein the mask correction device further comprises further comprising a controllable polarizer arranged to selectively impart a desired polarization state to the second radiation beam. 
     
     
       13. The lithographic apparatus of  claim 12 , wherein the controllable polarizer comprises a polarizer and a switching device arranged to selectively move the polarizer into and out of the second radiation beam. 
     
     
       14. The lithographic apparatus of  claim 1 , further comprising a mask inspection device and wherein the mask correction device is configured to change one or more optical elements are arranged to direct the second radiation beam onto the mask when the mask is in a position to be inspected by the mask inspection device. 
     
     
       15. A method of correcting a mask for use in a lithographic device manufacturing method process, the method comprising:
 in a lithographic apparatus, directing a first radiation beam to be incident selectively on a spot on the mask to controllably and locally deform alter a geometry of material constituting part of, or controllably and locally alter a materials property within, a portion of the integral physical structure of the mask to respectively a desired altered geometry or desired altered materials property for use of in incidence of a second radiation different from the first radiation beam onto the portion of the mask having the locally deformed material altered material geometry or altered materials property in patterning of a the second radiation beam. 
 
     
     
       16. The method of  claim 15 , wherein the property of the mask that is locally altered by the first radiation beam is one or more selected from the group consisting of: transmissivity to the second radiation beam used in the lithographic device manufacturing method process; transmissivity to a polarization state of the second radiation beam; birefringence; and geometry. 
     
     
       17. The method of  claim 15 , wherein directing comprises directing the first radiation beam onto a plurality of spots on the mask substantially simultaneously. 
     
     
       18. The method of  claim 17 , further comprising scanning the mask relative to the first radiation beam in a first direction while performing the directing. 
     
     
       19. A device manufacturing method using a lithographic apparatus, the method comprising:
 in the lithographic apparatus, directing a first radiation beam to be incident selectively on a spot on a mask to controllably and locally deform alter a geometry of material constituting part of, or controllably and locally alter a materials property within, a portion of the integral physical structure of the mask to respectively a desired altered geometry or desired altered materials property; 
 directing a second radiation beam, different from the first radiation beam, onto the portion of the mask; and 
 projecting the second radiation beam patterned by the mask having the locally deformed material altered material geometry or altered materials property onto a substrate. 
 
     
     
       20. The method of  claim 19 , wherein directing the first radiation beam comprises directing the first radiation beam onto a plurality of spots on the mask substantially simultaneously. 
     
     
       21. A non-transitory computer program product comprising instructions, that when executed by one or more computers, are configured to cause the one or more computers to at least cause apparatus, in a lithographic apparatus, to direct a first radiation beam to be incident selectively on a spot on a mask for use in a lithographic device manufacturing process to controllably and locally alter a geometry of material constituting part of, or controllably or locally alter a materials property within, a portion of the integral physical structure of the mask to respectively a desired altered geometry or desired altered materials property for use in incidence of a second radiation beam different from the first radiation beam onto the portion of the mask having the locally altered geometry or altered materials property in patterning of the second radiation beam.  
     
     
       22. The computer program product of  claim 21 , wherein the property of the mask that is locally altered by the first radiation beam is one or more selected from the group consisting of: transmissivity to the second radiation beam used in the lithographic device manufacturing process; transmissivity to a polarization state of the second radiation beam; birefringence; and geometry.  
     
     
       23. The computer program product of  claim 21 , wherein the instructions configured to cause the one or more computers to at least cause the directing of the first radiation beam are further configured to cause the directing of the first radiation beam onto a plurality of spots on the mask substantially simultaneously.  
     
     
       24. The computer program product of  claim 23 , wherein the plurality of spots are arranged in a two-dimensional array, at least either rows or columns of the two-dimensional array of spots forming an acute angle to the first direction.  
     
     
       25. The computer program product of  claim 21 , wherein the instructions are further configured to cause the one or more computers to at least cause scanning of the mask relative to the first radiation beam in a first direction during the directing.  
     
     
       26. The computer program product of  claim 21 , wherein the instructions are further configured to cause the one or more computers to at least cause division of the first radiation beam into a plurality of sub-beams to be incident on the mask at respective spaced apart spots, and cause selective direction of each of the sub-beams to respective spots on the mask.  
     
     
       27. The computer program product of  claim 26 , wherein the instructions are further configured to cause the one or more computers to at least cause the division by a microlens array and to cause the selective direction by an array of movable mirrors, each microlens of the microlens array being arranged to focus a sub-beam on a respective one of the movable mirrors.  
     
     
       28. The computer program product of  claim 27 , wherein each movable mirror is movable between a first position at which a respective one of the sub-beams is directed to be incident on a respective spot on the mask and a second position at which the respective one of the sub-beams is directed to not be incident on the mask.  
     
     
       29. The computer program product of  claim 28 , wherein each movable mirror is movable between a plurality of positions at each of which a respective one of the sub-beams is directed to be incident on a respective spot on the mask.  
     
     
       30. The computer program product of  claim 21 , wherein the instructions are further configured to cause the one or more computers to at least cause a controllable polarizer to selectively impart a desired polarization state to the first radiation beam.  
     
     
       31. The computer program product of  claim 30 , wherein the instructions are further configured to cause the one or more computers to at least cause a switching device to selectively move a polarizer into and out of the first radiation beam.  
     
     
       32. The computer program product of  claim 21 , wherein the instructions are further configured to cause the one or more computers to at least cause alteration of the geometry of the material or alteration of the property of the mask when the mask is in a position to be inspected by a mask inspection device of the lithographic apparatus.