Mirror element, in particular for a microlithographic projection exposure apparatus

Abstract

A mirror element, in particular for a microlithographic projection exposure apparatus. According to one aspect, the mirror element includes a substrate ( 111, 112, 113, 114, 115, 211, 212, 213, 311 a - 311 m, 411, 412, 413 ) and a layer stack ( 121, 122, 123, 124, 125, 221, 222, 223, 321 a - 321 m, 421, 422, 423 ) on the substrate. The layer stack has at least one reflection layer system, wherein a curvature of the mirror element is generated on the basis of a setpoint curvature for a predetermined operating temperature by a non-vanishing bending force exerted by the layer stack, wherein the generated curvature varies by no more than 10% over a temperature interval (ΔT) of at least 10 K.

1 . The mirror element, according to  claim 7 ,
 wherein a curvature of the mirror element is generated on a basis of a setpoint curvature for a predetermined operating temperature by a non-vanishing bending force exerted by the layer stack; and   wherein the generated curvature varies by no more than 10% over a temperature interval (ΔT) of at least 10 K.   
     
     
         2 . The mirror element according to  claim 1 , wherein the generated curvature varies by no more than 1% over a temperature interval (ΔT) of at least 10 K. 
     
     
         3 . The mirror element according to  claim 1 , further comprising a compensation layer which at least partly compensates a variation of the bending force exerted by the layer stack accompanying a change in temperature occurring within the temperature interval (ΔT). 
     
     
         4 . (canceled) 
     
     
         5 . The mirror element according to  claim 1 , wherein a mean coefficient of thermal expansion of the substrate has a first value and a mean coefficient of thermal expansion of the layer stack has a second value, wherein the first value and the second value correspond to within ±10% in relation to the larger one of the two values. 
     
     
         6 . The mirror element according to  claim 5 , wherein the substrate is produced from at least two different materials. 
     
     
         7 . A mirror element, comprising:
 a substrate;   a layer stack on the substrate, wherein the layer stack has at least one reflection layer system; and   an equalization layer which reduces a transfer of mechanical tension between the layer stack and the substrate compared to an analogous mirror element without the equalization layer.   
     
     
         8 . The mirror element according to  claim 7 , further comprising a tension-inducing layer. 
     
     
         9 . A mirror arrangement comprising:
 a plurality of mirror elements, each said mirror element comprising:
 a substrate; 
 a layer stack on the substrate, wherein the layer stack has at least one reflection layer system; and 
 an equalization layer which reduces a transfer of mechanical tension between the layer stack and the substrate compared to an analogous mirror element without the equalization layer. 
   
     
     
         10 . The mirror arrangement according to  claim 9 , wherein the mirror elements are configured to tilt independently of one another. 
     
     
         11 . The mirror arrangement according to  claim 9 , wherein the mirror arrangement is a facet mirror comprising the mirror elements. 
     
     
         12 . The mirror element according to  claim 7 , configured for an operating wavelength of less than 30 nm. 
     
     
         13 . The mirror element according to  claim 7 , configured for operation in a microlithographic projection exposure apparatus. 
     
     
         14 . An optical system of a microlithographic projection exposure apparatus, comprising at least one mirror element according to  claim 13 . 
     
     
         15 . A microlithographic projection exposure apparatus comprising an illumination device and a projection lens, wherein the illumination device or the projection lens comprises the mirror element according to  claim 13 . 
     
     
         16 . The mirror element according to  claim 1 , configured for operation in a microlithographic projection exposure apparatus. 
     
     
         17 . The mirror element according to  claim 2 , wherein the generated curvature varies by no more than 0.1% over a temperature interval (ΔT) of at least 10 K. 
     
     
         18 . The mirror element according to  claim 5 , wherein the first value and the second value correspond to within ±1%, in relation to the larger one of the two values. 
     
     
         19 . The mirror element according to  claim 7 , configured for operation in a microlithographic projection exposure apparatus. 
     
     
         20 . The mirror arrangement according to  claim 11 , wherein the facet mirror is configured as a field facet mirror or as a pupil facet mirror.