Microlithographic projection exposure apparatus

Abstract

The disclosure relates to a microlithographic projection exposure apparatus, such as are used for the production of large-scale integrated electrical circuits and other microstructured components. The disclosure relates in particular to coatings of optical elements in order to increase or reduce the reflectivity.

What is claimed is: 
     
         1 . An optical system, comprising:
 a plurality of optical elements; and   a plurality of antireflection coatings comprising a first antireflection coating and a second antireflection coating which is different from the first antireflection coating,   wherein:
 each of the plurality of optical elements supports at least one of the plurality of antireflection coatings; and 
 within a first incidence angle range, the first antireflection coating has a polarisation-dependent reflectivity which is greater for s-polarised light than for p-polarised light; 
 within a second incidence angle range, the second antireflection coating has a polarisation-dependent reflectivity which is less for s-polarised light than for p-polarised light; 
 during use of the optical system, the first and second antireflection coatings are in a path of light as it propagates through the optical system so that polarisation-dependent differences in reflectivity of the first and second antireflection coatings at least partially compensate each other; and 
 the optical system is a microlithographic optical system. 
   
     
     
         2 . The optical system of  claim 1 , wherein, during use of the optical system, at least some rays of the light impinge on the first antireflection coating with incidence angles lying within the first incidence angle range, and also impinge on the second antireflection coating with incidence angles lying within the second incidence angle range. 
     
     
         3 . The optical system of  claim 1 , wherein the first incidence angle range is at least substantially identical to the second incidence angle range. 
     
     
         4 . The optical system of  claim 3 , wherein the first and second antireflection coatings are supported by the same optical element. 
     
     
         5 . The optical system of  claim 1 , wherein the first incidence angle range is different from the second incidence angle range. 
     
     
         6 . The optical system of  claim 5 , wherein:
 the plurality of optical elements comprises a first optical element and a second optical element which is different from the first optical element;   the first antireflection coating is supported by the first optical element; and   the second antireflection coating is supported by the second optical element.   
     
     
         7 . The optical system of  claim 1 , wherein the polarisation-dependent differences in reflectivity for the first and second antireflection coatings compensate each other so that a total transmission of the optical system does not depend on a state of polarisation of the projection light. 
     
     
         8 . The optical system of  claim 1 , further comprising:
 a third antireflection coating configured so that, during use of the optical system, within a third incidence angle range, p-polarised light passes through the third antireflection coating with a retardation relative to s-polarised light; and   a fourth antireflection coating configured so that, during use of the optical system, within a fourth incidence angle range, s-polarised light passes through the fourth antireflection coating with a retardation relative to p-polarised light,   wherein the third and fourth antireflection coatings are configured so that, during use of the optical system, polarisation-dependent differences in reflectivity of the third and fourth antireflection coatings at least partially compensate each other.   
     
     
         9 . The optical system of  claim 1 , wherein a portion of the first incidence angle range overlaps with a portion of the second incidence angle range. 
     
     
         10 . An optical system, comprising:
 a plurality of optical elements; and   a plurality of antireflection coatings comprising a first antireflection coating and a second antireflection coating which is different from the first antireflection coating,   wherein:
 each optical element supports at least one of the plurality of antireflection coatings; and 
 within a first incidence angle range, p-polarised light passes through the first antireflection coating with a retardation relative to s-polarised light; 
 within a second incidence angle range, s-polarised light passes through the second antireflection coating with a retardation relative to p-polarised light; 
 during use of the optical system, the first and second antireflection coatings are in a path of light as it propagates through the optical system so that polarisation-dependent differences in reflectivity of the first and second antireflection coatings at least partially compensate each other; and 
 the optical system is a microlithographic optical system. 
   
     
     
         11 . The optical system of  claim 10 , wherein, during use of the optical system, at least some rays of the light impinge on the first antireflection coating with incidence angles lying within the first incidence angle range, and also impinge on the second antireflection coating with incidence angles lying within the second incidence angle range. 
     
     
         12 . The optical system of  claim 10 , wherein the first incidence angle range is at least substantially identical to the second incidence angle range. 
     
     
         13 . The optical system of  claim 12 , wherein the first and second antireflection coatings are supported by the same optical element. 
     
     
         14 . The optical system of  claim 10 , wherein the first incidence angle range is different from the second incidence angle range. 
     
     
         15 . The optical system of  claim 14 , wherein the first antireflection coating is supported by a first optical element, and the second antireflection coating is supported by a second optical element. 
     
     
         16 . The optical system of  claim 10 , wherein:
 the plurality of optical components comprises a first optical element and a second optical element which is different from the first optical element;   the first antireflection coating is supported by the first optical element; and   
       the second antireflection coating is supported by the second optical element. 
     
     
         17 . The optical system of  claim 10 , wherein a portion of the first incidence angle range overlaps with a portion of the second incidence angle range. 
     
     
         18 . An optical system, comprising:
 a plurality of optical elements; and   a plurality of antireflection coatings comprising a first antireflection coating and a second antireflection coating which is different from the first antireflection coating,   wherein:
 each of the plurality of optical elements supports at least one of the plurality of antireflection coatings, 
 each antireflection coating has a polarisation-dependent reflectivity; 
 during use of the optical system, light propagates through the optical system and interacts with the antireflection coatings such that a combination of each of the plurality of antireflection coatings has a substantially polarisation-neutral reflectivity of the light; and 
 the optical system is a microlithographic optical system. 
   
     
     
         19 . The optical system of  claim 18 , wherein:
 within a first incidence angle range, the first antireflection coating has a polarisation-dependent reflectivity which is greater for s-polarised light than for p-polarised light;   within a second incidence angle range, the second antireflection coating has a reflectivity which is less for s-polarised light than for p-polarised light; and   the first and second antireflection coatings are arranged so that, during use of the optical system, their polarisation-dependent differences in reflectivity at least partially compensate each other.   
     
     
         20 . The optical system of  claim 19 , wherein each antireflection coating has polarisation-dependent behaviour with respect to a phase of the light, and the combination of all antireflection coatings has a substantially polarisation-neutral behaviour with respect to the phase of the light. 
     
     
         21 . The optical system of  claim 20 , further comprising:
 a third antireflection coating configured so that, within a third incidence angle range, p-polarised light passes through the third antireflection coating with a retardation relative to s-polarised light; and   a fourth antireflection coating configured so that, within a fourth incidence angle range, s-polarised light passes through the fourth antireflection coating with a retardation relative to p-polarised light,   wherein the third and fourth antireflection coatings are arranged so that, during use of the optical system, they are in the path of the light and polarisation-dependent phase differences between the third and fourth antireflection coatings at least partially compensate each other.   
     
     
         22 . The optical system of  claim 21 , wherein a portion of the first incidence angle range overlaps with a portion of the second incidence angle range. 
     
     
         23 . The optical system of  claim 18 , wherein each antireflection coating has polarisation-dependent behaviour with respect to a phase of the light, and the combination of all antireflection coatings has a substantially polarisation-neutral behaviour with respect to the phase of the light. 
     
     
         24 . The optical system of  claim 23 , further comprising:
 a third antireflection coating configured so that, within a third incidence angle range, p-polarised light passes through the third antireflection coating with a retardation relative to s-polarised light; and   a fourth antireflection coating configured so that, within a fourth incidence angle range, s-polarised light passes through the fourth antireflection coating with a retardation relative to p-polarised light,   wherein the third and fourth antireflection coatings are arranged so that, during use of the optical system, they are in the path of the light and polarisation-dependent phase differences between the third and fourth antireflection coatings at least partially compensate each other.   
     
     
         25 . The optical system of  claim 18 , further comprising:
 a third antireflection coating configured so that, within a third incidence angle range, p-polarised light passes through the third antireflection coating with a retardation relative to s-polarised light; and   a fourth antireflection coating configured so that, within a fourth incidence angle range, s-polarised light passes through the fourth antireflection coating with a retardation relative to p-polarised light,   wherein the third and fourth antireflection coatings are arranged so that, during use of the optical system, they are in the path of the light and polarisation-dependent phase differences between the third and fourth antireflection coatings at least partially compensate each other.   
     
     
         26 . The optical system of  claim 18 , wherein a portion of the first incidence angle range overlaps with a portion of the second incidence angle range. 
     
     
         27 . An optical system, comprising:
 a plurality of optical elements; and   a plurality of antireflection coatings comprising a first antireflection coating and a second antireflection coating which is different from the first antireflection coating,   wherein:
 each of the plurality of optical elements supports at least one of the antireflection coatings; 
 each antireflection coating has polarisation-dependent behaviour with respect to a phase of the light; 
 during use of the optical system, light propagates through the optical system and interacts with the antireflection coatings such that a combination of each of the plurality of antireflection coatings has a substantially polarisation-neutral behaviour with respect to the phase of the light; and 
 the optical system is a microlithographic optical system. 
   
     
     
         28 . The optical system of  claim 27 , wherein:
 the first antireflection coating is configured so that, within a first incidence angle range, p-polarised light passes through the first antireflection coating with a retardation relative to s-polarised light; and   the second antireflection coating is configured so that, within a second incidence angle range, s-polarised light passes through the second antireflection coating with a retardation relative to p-polarised light.   
     
     
         29 . The optical system of  claim 28 , wherein a portion of the first incidence angle range overlaps with a portion of the second incidence angle range. 
     
     
         30 . The optical system of  claim 27 , wherein a portion of the first incidence angle range overlaps with a portion of the second incidence angle range.