Illuminant distribution evaluation method, optical member manufacturing method, illumination optical device, exposure apparatus, and exposure method

Abstract

There is disclosed an evaluation method for evaluating a one-dimensional illumination distribution using polynomials, the method comprising steps of: setting up, as the polynomials, one-dimensional power polynomials which are orthogonal in a closed interval; and approximating the one-dimensional illumination distribution with the power polynomials to obtain the coefficients of respective terms of the power polynomials.

1 . A method for measuring illumination distribution using an imaging device, the method comprising:
 acquiring the offset for correcting the influence on the actual measurement result of the illumination distribution caused by the sensitivity non-uniformity on the imaging plane of the imaging device; and   correcting the actual measurement result of the illumination distribution, based on the offset.   
   
   
       2 . The illumination measurement method according to  claim 1 , wherein the acquiring the offset comprises:
 obtaining a first measurement data by measuring a first illumination distribution using the imaging element;   obtaining a first reference data by measuring the first illumination distribution using a measurement means which will not be substantially influenced by sensitivity non-uniformity on the imaging plane;   obtaining a second measurement data by measuring a second illumination distribution which is different from the first illumination distribution using the imaging device;   obtaining a second reference data by measuring the second illumination distribution using the measurement means;   making origins of the first measurement data and the second measurement data in coincidence with the origins of the first reference data and the second reference data so that the difference between the first measurement data and the second measurement data approximately matches the difference between the first reference data and the second reference data; and   setting up the offset based on at least either one of the difference between the first measurement data and the first reference data and the difference between the second measurement data and the second reference data, under a condition that the origins of the first measurement data and the second measurement data have been made in coincidence with the origins of the first reference data and the second reference data.   
   
   
       3 . The illumination measurement method according to  claim 2 , wherein the mean value of the difference between the first measurement data and the first reference data and the difference between the second measurement data and the second reference data is set as the offset in the setting up the offset. 
   
   
       4 . The illumination measurement method according to  claim 1 , wherein the acquiring the offset comprises:
 obtaining measurement data by measuring a predefined illumination distribution using the imaging device;   obtaining reference data by measuring the predefined illumination distribution using a measurement means which will not be substantially influenced by sensitivity non-uniformity on the imaging plane; and   setting the difference between the measurement data and the reference data as the offset.   
   
   
       5 . The illumination measurement method according to  claim 1 , wherein the imaging device is a CCD. 
   
   
       6 . An illumination measurement apparatus for measuring the illumination distribution according to the illumination measurement method of  claim 1 , the apparatus comprising:
 an imaging device for measuring the illumination distribution; and   a processing unit for correcting the actual measurement result of the illumination distribution obtained in the imaging device, based on the offset.   
   
   
       7 . A manufacturing method of an optical member, the method comprising:
 generating a predefined illumination distribution by means of the optical member; and   measuring the illumination distribution using the illumination measurement method of  claim 1 .   
   
   
       8 . An optical member manufactured using the manufacturing method of  claim 7 . 
   
   
       9 . An exposure apparatus having the illumination optical apparatus according to  claim 6 , wherein a mask pattern disposed on the plane to be illuminated is exposed onto a photosensitive substrate. 
   
   
       10 . The exposure apparatus according to  claim 9 , further comprising:
 projection optics for forming the mask pattern image on the photosensitive substrate, and arranged so as to transfer the mask pattern onto the photosensitive substrate while displacing the mask and the photosensitive substrate relatively to the projection optics along a scanning direction,   wherein a two-dimensional illumination distribution is converted into a one-dimensional illumination distribution along a direction which is orthogonal to the scanning direction.