Method for improving an optical imaging property of a projection objective of a microlithographic projection exposure apparatus

Abstract

A method is disclosed for improving an optical imaging property, for example spherical aberration or the focal length, of a projection objective of a microlithographic projection exposure apparatus. First, an immersion liquid is introduced into an interspace between a photosensitive surface and an end face of the projection objective. Then an imaging property of the projection objective is determined, for example using an interferometer or a CCD sensor arranged in an image plane of the projection objective. This imaging property is compared with a target imaging property. Finally, the temperature of the immersion liquid is changed until the determined imaging property is as close as possible to the target imaging property.

1 . (canceled) 
     
     
         2 . An exposure apparatus which exposes a substrate with an exposure light beam, comprising:
 a liquid immersion mechanism which forms a liquid immersion area of the liquid in an optical path of the exposure light beam; and   a measuring device which measures a pattern formation state of a pattern formed through the liquid forming the liquid immersion area.   
     
     
         3 . The exposure apparatus according to  claim 2 , wherein the measuring device measures an aerial image of the pattern. 
     
     
         4 . The exposure apparatus according to  claim 2 , further comprising a controller which determines an exposure condition for exposing the substrate based on the pattern formation state of the pattern measured by the measuring device. 
     
     
         5 . The exposure apparatus according to  claim 4 , wherein the exposure condition includes a liquid condition of the liquid. 
     
     
         6 . The exposure apparatus according to  claim 2 , further comprising a controller which performs control to expose under an exposure condition determined based on a result of a measurement of a pattern formation state of a pattern formed through the liquid forming the liquid immersion area. 
     
     
         7 . The exposure apparatus of according to  claim 2 , further comprising a controller which sets a liquid condition of the liquid forming the liquid immersion area at a predetermined state, wherein the measuring device measures the pattern formation state of the pattern formed through the liquid under the set liquid condition. 
     
     
         8 . The exposure apparatus according to  claim 2 , further comprising a controller which sets the liquid at a predetermined state to perform an exposure under an exposure condition determined based on the pattern formation state of the pattern formed through the liquid. 
     
     
         9 . An exposure apparatus which exposes a substrate with an exposure light beam, comprising:
 a liquid immersion mechanism which forms a liquid immersion area of the liquid in an optical path for the exposure light beam; and   a controller which performs control to expose under an exposure condition determined based on a result of a measurement of a pattern formation state of a pattern formed through the liquid forming the liquid immersion area.   
     
     
         10 . The exposure apparatus according to  claim 9 , wherein the exposure condition includes a liquid condition of the liquid. 
     
     
         11 . The exposure apparatus according to  claim 9 , further comprising an optical system which forms the pattern onto the substrate, wherein the exposure condition includes a state of a wavefront aberration of the optical system. 
     
     
         12 . A method for determining an exposure condition for exposing a substrate through a liquid, comprising:
 setting a liquid condition of the liquid at a predetermined state;   forming a plurality of images of a pattern through the liquid under the liquid condition, the images being formed under mutually different exposure conditions;   measuring a pattern formation state of each of the images of the pattern; and   determining the exposure condition among the different exposure conditions based on the measured images of the pattern.   
     
     
         13 . An exposure method for exposing a substrate using an exposure condition determined by the method as defined in  claim 12 . 
     
     
         14 . The method of  claim 12 , wherein the method is performed using an exposure apparatus in accordance with  claim 2 . 
     
     
         15 . An exposure apparatus which exposes a substrate with an exposure light beam, comprising:
 a liquid immersion mechanism which forms a liquid immersion area of a liquid in an optical path for the exposure light beam;   a controller which sets a liquid condition of the liquid forming the liquid immersion area at a predetermined state; and   a measuring device which measures a pattern formation state of a pattern formed through the liquid under the set liquid condition.   
     
     
         16 . The exposure apparatus according to  claim 15 , wherein the pattern formation state of the pattern is corrected based on a result of a measurement by the measuring device. 
     
     
         17 . The exposure apparatus according to  claim 16 , further comprising:
 an optical system which forms the pattern on the substrate; and   an image formation characteristic adjusting device which adjusts an image formation characteristic of the optical system to correct the pattern formation state of the pattern.   
     
     
         18 . An exposure apparatus which exposes a substrate with an exposure light beam, comprising:
 a liquid immersion mechanism which forms a liquid immersion area of a liquid in an optical path for the exposure light beam; and   a controller which sets the liquid at a predetermined state to perform an exposure under an exposure condition determined based on a pattern formation state of a pattern formed through the liquid.   
     
     
         19 . The exposure apparatus according to  claim 18 , wherein the exposure condition includes a liquid condition of the liquid. 
     
     
         20 . The exposure apparatus according to  claim 18 , further comprising an optical system which forms the pattern onto the substrate, wherein the exposure condition includes a state of a wavefront aberration of the optical system.