Microlithography projection objective

Abstract

Microlithography projection objectives for imaging into an image plane a pattern arranged in an object plane are described with respect to suppressing false light in such projection objectives.

1 . A projection objective, comprising:
 a plurality of optical components configured to image into an image plane a pattern arranged in an object plane, the plurality of optical components comprising a mirror, an imaging beam path that can be used for imaging the pattern into the image plane having in the region of the mirror beam path segments that run obliquely relative to one another and overlap one another at least partially in an overlap region and are spaced apart from one another outside the overlap region by a gap; and   a shield configured to suppress false light being arranged in the gap,   wherein the projection objective is a microlithography projection.   
     
     
         2 . The projection objective of  claim 1 , wherein the shield is fastened on the first mirror. 
     
     
         3 . The projection objective of  claim 1 , wherein the plurality of optical components further includes a lens to form a catadioptric system. 
     
     
         4 . The projection objective of  claim 1 , wherein the plurality of optical components has an optical axis. 
     
     
         5 . The projection objective of  claim 4 , wherein the shield configured to suppress false light comprises a section extending substantially parallel to the optical axis. 
     
     
         6 . The projection objective of  claim 1 , further comprising an aperture stop defining the system aperture and having an optically effective cross-section, wherein the optically effective cross-section is adjustable. 
     
     
         7 . The projection objective of  claim 1 , wherein the plurality of optical components includes a first mirror and a second mirror one of the beam path segments is a beam path segment reflected by the second mirror another one of the beam path segments is a beam path segment reflected by the first mirror and the shield is arranged between the first mirror and the second mirror in the gap between the two reflecting beam path segments. 
     
     
         8 . The projection objective of  claim 7 , wherein the shield is fastened on the first mirror. 
     
     
         9 . The projection objective of  claim 7 , wherein the shield is fastened on the second mirror. 
     
     
         10 . The projection objective of  claim 1 , wherein the shield is a plate or an aperture. 
     
     
         11 . A objective configured to image into an image plane a pattern arranged in an object plane, the projection objective comprising:
 a first objective part;   a second objective part;   a third objective part, the second objective part defining a light propagation direction that differs from a light propagation direction in the first objective part and from a light propagation direction in the third objective part,   a beam deflecting device between the first and second objective parts and between the second and third objective parts; and   a shield being arranged in the region of the beam deflecting device in such a way that during use direct light leakage from the first objective part into the third objective part is at least reduced,   wherein the projection objective is a microlithography projection objective.   
     
     
         12 . The projection objective of  claim 11 , wherein the shield does not limit the imaging beam path. 
     
     
         13 . The projection objective of  claim 11 , wherein the beam deflecting device has a first reflecting surface and a second reflecting surface that are arranged at an angle to one another, and wherein the shield extends in the direction of the second objective part starting from the angle vertex of the beam deflecting device. 
     
     
         14 . The projection objective of  claim 13 , wherein the shield is a plate. 
     
     
         15 . The projection objective of  claim 13 , wherein the shield is absorbing or is coated with an absorbing layer. 
     
     
         16 . The projection objective of  claim 11 , wherein the intermediate image is produced in the second and/or third objective part, and a further shield is arranged in the region of the intermediate image. 
     
     
         17 . The projection objective of  claim 16 , wherein the further shield is an aperture that does not limit the imaging beam path. 
     
     
         18 . The projection objective of  claim 11 , wherein the second objective part is catadioptric. 
     
     
         19 . The projection objective of  claim 11 , wherein the third objective part is dioptric. 
     
     
         20 . The projection objective of  claim 11 , wherein the shield can be adjusted in position and/or can be variably set with regard to its active cross section. 
     
     
         21 . The projection objective of  claim 20 , wherein the setting of the shield can be performed in common with the setting of an aperture of the objective that limits the imaging beam path. 
     
     
         22 . The projection objective of  claim 20 , wherein the setting of the shield is a function of the size of the image filed used for imaging. 
     
     
         23 . The projection objective of  claim 20 , wherein the setting of the shield can be performed as a function of the illumination setting. 
     
     
         24 . The projection objective of  claim 11 , wherein at least a further shield is arranged to shield over-aperture light from the object plane. 
     
     
         25 . A projection objective configured to image into an image plane a pattern arranged in an object plane, the projection objective comprising:
 a plurality of optical components that respectively have an optically active surface, wherein there is present a first optical component of the plurality of optical components that has a first optically operative surface that, during the operation of the projection objective, has a first surface region not used by the imaging beam path for imaging the pattern into the image plane, the first optically operative surface being assigned a first shield that masks out the first surface region, not used by the imaging beam path, of the first optically operative surface in order to suppress false light,   wherein the projection objective is a microlithography projection objective.   
     
     
         26 . The projection objective of  claim 25 , wherein the first shield is a plate arranged in the immediate vicinity of the first optically operative surface. 
     
     
         27 . The projection objective of  claim 25 , wherein the first shield is an aperture arranged in the immediate vicinity of the first optically operative surface and has an opening that is adapted to the cross-sectional shape of the imaging beam path at the location of the aperture. 
     
     
         28 . The projection objective of  claim 27 , wherein the opening is substantially rectangular. 
     
     
         29 . The projection objective of  claim 25 , wherein the first shield is a shielding coating on the first surface region not used by the imaging beam path. 
     
     
         30 . The projection objective of  claim 25 , wherein the first shield is reflective for a wavelength of the light used for imaging. 
     
     
         31 . The projection objective of  claim 25 , wherein the first shield is absorbing for a wavelength of the light used to image or is provided with an absorbing coating. 
     
     
         32 . The projection objective of  claim 31  wherein the absorbance of the shield is at least approximately 95%. 
     
     
         33 . The projection objective of  claim 31 , wherein the first shield has photocatalytic properties. 
     
     
         34 . The projection objective of  claim 25 , wherein the first optically operative surface that is assigned the first shield is a near-field surface. 
     
     
         35 . The projection objective of  claim 25 , wherein the shield is arranged between the object plane and the first optical component of the projection objective, and/or between the last optical component of the projection objective and the image plane. 
     
     
         36 . The projection objective of  claim 25 , wherein the optical component whose optically operative surface is assigned the shield is a mirror. 
     
     
         37 . The projection objective of  claim 25  wherein the optical component whose optically operative surface is assigned the shield is a lens. 
     
     
         38 . The projection objective of  claim 25 , wherein the first shield can be adjusted in position and/or can be variably set with regard to its active cross section. 
     
     
         39 . The projection objective of  claim 38 , wherein the setting of the first shield can be performed in common with the setting of an aperture of the projection objective that limits the imaging beam path. 
     
     
         40 . The projection objective of  claim 38 , wherein the setting of the first shield is a function of the size of the image field used for imaging. 
     
     
         41 . The projection objective of  claim 38 , wherein the setting of the first shield can be performed as a function of the illumination setting. 
     
     
         42 . The projection objective of  claim 25 , wherein the plurality of optical components have a further optical component that has a further optically operative surface that, during operation of the projection objective, has a further surface region not used by the imaging beam path for imaging the pattern into the image plane, the further optically operative surface being assigned a further shield that masks out the further surface region, not used by the imaging beam path, of the further optically operative surface. 
     
     
         43 . The projection objective of  claim 25 , wherein the plurality of optical components comprises at least two mirrors. 
     
     
         44 . The projection objective of  claim 43 , wherein the plurality of optical components comprises at least four mirrors. 
     
     
         45 . The projection objective of  claim 25 , wherein it is designed as an immersion objective. 
     
     
         46 . The projection objective of  claim 25 , wherein a further shield is arranged to shield over-aperture light from the object plane. 
     
     
         47 . A projection objective configured to image into an image plane a pattern arranged in an object plane, the projection objective having a first pupil plane and a second pupil plane, the projection objective comprising:
 a plurality of optical components;   a first aperture stop defining the system aperture being arranged at least near the first pupil plane; and   a second aperture stop,   wherein the projection objective is a microlithography projection objective.   
     
     
         48 . The projection objective of  claim 47 , wherein the second aperture stop is arranged near the first or second pupil plane. 
     
     
         49 . The protection objective of  claim 48 , wherein the second aperture stop is arranged in the second pupil plane. 
     
     
         50 . The projection objective of  claim 47 , wherein the second aperture stop is a fixed aperture stop. 
     
     
         51 . The projection objective of  claim 47 , the first aperture stop is adjustable with respect to its effective cross-section. 
     
     
         52 . The projection objective of  claim 47 , wherein the second aperture stop is formed by a non-transmissive coating on an optical component of the plurality of optical components. 
     
     
         53 . The projection objective of  claim 47 , wherein the second aperture stop is formed by a plate arranged between two neighboring components of the plurality of optical components. 
     
     
         54 . The projection objective of  claim 47 , wherein at least one of the optical components of the plurality of optical components has an aspherical optically operative surface. 
     
     
         55 . The protection objective of  claim 47 , having a numerical aperture on the image side which is larger than about 0.8. 
     
     
         56 . The projection objective of  claim 47 , wherein a distance L of the at least one second aperture stop from the pupil plane nearest to the image plane is chosen such that 0.5D<L<2D, wherein D is a diameter of an optical component of the plurality of optical components which has the maximum diameter of the optical components. 
     
     
         57 . The projection objective of  claim 47 , having an intermediate image plane between the first pupil plane and the second pupil plane. 
     
     
         58 . A microlithography projection exposure machine having a projection objective as claimed in  claim 1 . 
     
     
         59 . A method, comprising:
 illuminating with ultraviolet light a mask having a pattern via a projection objective as claimed in  claim 1 ; and   imaging the pattern onto a photosensitive substrate arranged in the region of an image plane of the projection objective.