Source Multiplexing in Lithography

Abstract

An illumination system for an extreme ultraviolet (EUV) lithography system may include multiple sources of EUV light. The system may combine the light from the multiple sources when illuminating a mask.

1 . A method comprising: 
 generating electromagnetic radiation that is suitable for lithography at a first source;    generating electromagnetic radiation that is suitable for lithography at a second source;    dividing the electromagnetic radiation generated by the first source into a first collection of beams;    dividing the electromagnetic radiation generated by the second source into a second collection of beams;    directing the electromagnetic radiation in the beams of the first collection to a position in a lithography system, with electromagnetic radiation in the beams of the first collection arriving at the position with a first collection of incidence angles; and    directing the electromagnetic radiation in the beams of the second collection to the position in the lithography system, with electromagnetic radiation in the beams of the second collection arriving at the position with a second collection of incidence angles,    wherein incidence angles of electromagnetic radiation in the first collection of beams are interleaved with incidence angles of electromagnetic radiation in the second collection of beams.    
   
   
       2 . The method of  claim 1 , wherein the incidence angles of electromagnetic radiation in the first collection of beams are interleaved with the incidence angles of electromagnetic radiation in the second collection of beams so that variations in the generation of electromagnetic radiation by either the first source or the second source do not substantially change the net weighted incidence angle of electromagnetic radiation at the position.  
   
   
       3 . The method of  claim 1 , wherein: 
 dividing the electromagnetic radiation generated by the first source comprises collecting the electromagnetic radiation generated by the first source using a first collection of spaced apart collector optical elements; and    dividing the electromagnetic radiation generated by the second source comprises collecting the electromagnetic radiation generated by the second source using a second collection of spaced apart collector optical elements.    
   
   
       4 . The method of  claim 3 , wherein at least some of the collector optical elements in the first collection are interspersed amongst the collector optical elements in the second collection.  
   
   
       5 . The method of  claim 4 , wherein at least some of the collector optical elements in the first collection are interspersed vertically and horizontally amongst the collector optical elements in the second collection.  
   
   
       6 . The method of  claim 3 , wherein the collector optical elements in the first collection and the second collection comprise hexagonal reflectors.  
   
   
       7 . The method of  claim 3 , wherein the position is at a pupil in the lithography system.  
   
   
       8 . A system comprising: 
 a first source of electromagnetic radiation that is suitable for lithography;    a second source of electromagnetic radiation that is suitable for lithography;    a first collection of spaced apart collector optical elements associated with the first source;    a second collection of spaced apart collector optical elements associated with the second source, wherein at least some of the collector optical elements in the first collection are interspersed amongst the collector optical elements in the second collection; and    imaging optics arranged to direct electromagnetic radiation collected from the first source and electromagnetic radiation collected from the second source to the same substrate.    
   
   
       9 . The system of  claim 8 , wherein the system is to direct electromagnetic radiation collected from the first source and electromagnetic radiation collected from the second source to a position such that angles of incidence of the electromagnetic radiation collected from the first source at the position are interleaved with angles of incidence of the electromagnetic radiation collected from the second source at the same position.  
   
   
       10 . The system of  claim 8 , wherein: 
 the first source is positioned at foci of the first collection of collector optical elements; and    the second source is positioned at foci of the second collection of collector optical elements.    
   
   
       11 . The system of  claim 8 , wherein the collector optical elements in the first collection are interspersed vertically and horizontally amongst the collector optical elements in the second collection.  
   
   
       12 . The system of  claim 8 , wherein the collector optical elements in the first collection and the second collection comprise tessellate reflector surfaces.  
   
   
       13 . The system of  claim 12 , wherein the tessellate reflector surfaces comprise hexagonal reflector surfaces.  
   
   
       14 . The system of  claim 12 , wherein the tessellate reflector surfaces are arranged adjacent one another.  
   
   
       15 . A method comprising: 
 generating electromagnetic radiation that is suitable for lithography at a first source;    generating electromagnetic radiation that is suitable for lithography at a second source;    directing the electromagnetic radiation from the first source to a first location;    directing the electromagnetic radiation from the second source to a second location, wherein the first location is different from the second location; and    moving a patterned reticle relative to the first location and the second location so that different parts of the pattern on the reticle pass through the first location and the second location in succession to expose a position on the substrate that integrates the energy from the first source and from the second source.    
   
   
       16 . The method of  claim 15 , further comprising patterning a integrated circuit pattern on a substrate in accordance with a pattern on the patterned reticle.  
   
   
       17 . The method of  claim 15 , wherein moving the patterned reticle relative to the first location and the second location comprises scanning the patterned reticle across the first location and the second location.  
   
   
       18 . The method of  claim 17 , further comprising patterning a substrate by scanning the substrate while scanning the patterned reticle.  
   
   
       19 . The method of  claim 15 , wherein: 
 directing the electromagnetic radiation from the first source comprises directing the electromagnetic radiation to a first rectangular region; and    directing the electromagnetic radiation from the second source comprises directing the electromagnetic radiation to a second rectangular region.    
   
   
       20 . The method of  claim 15 , wherein the first location is adjacent to the second location.  
   
   
       21 . The method of  claim 20 , wherein: 
 moving the patterned reticle relative to the first location and the second location comprises scanning the patterned reticle relative to the first location and the second location in a first direction; and    the first location is adjacent to the second location in the first direction.