Method for detecting particles and defects and inspection equipment thereof

Abstract

A method and equipment which includes an illustrated-spot illumination-distribution data table for storing an illumination distribution within an illustrated spot and which calculates a coordinate position for a particle or a defect and the diameter of the particle on the basis of detection light intensity data about the particle or defect and the illustrated-spot illumination-distribution data table. Thus, even when the illumination distribution within the illustrated spot based on an actual illumination optical system is not a Gaussian distribution, the calculation of the particle diameter of the detected particle or defect and the calculation of a coordinate position on the surface of an object to be inspected can be attained with an increased accuracy.

The invention claimed is: 
     
       1. An inspection apparatus which detects an anomaly of a substrate comprising;
 an illuminating unit which supplies light and forms an illumination spot on said substrate; 
 a detection unit which detects light from said illumination spot; and 
 a processing unit, wherein said processing unit:
 acquires digital data expressed by a (r, θ) coordinate system by using a detection result of said detection unit, and 
 acquires digital data expressed by a two-dimensional Cartesian coordinate system by using a relative illumination distribution of said illumination spot, and said digital data expressed by the (r, θ) coordinate system. 
 
 
     
     
       2. An The inspection apparatus according  claim 1 , wherein
 said relative illumination distribution is expressed by the two-dimensional Cartesian coordinate system. 
 
     
     
       3. An The inspection apparatus according  claim 1 ,
 wherein said processing unit acquires position of said anomaly on said two-dimensional Cartesian coordinate system. 
 
     
     
       4. An The inspection apparatus according  claim 1 , further comprising:
 a changing unit which changes an optical condition of said illumination unit; 
 a memory which stores a plurality of relative illumination distributions corresponding to a plurality of optical conditions; and 
 a selecting unit which selects a relative illumination distribution corresponding to said optical condition changed by said changing unit from said relative illumination distributions. 
 
     
     
       5. An The inspection apparatus according to  claim 1 , wherein said processing unit corrects a tilt of said anomaly. 
     
     
       6. A method for detecting an anomaly of a substrate, the method comprising steps of:
 illuminating light on said substrate to form an illumination spot on said substrate; 
 detecting light from said illumination spot; 
 acquiring digital data expressed by a (r, θ) coordinate system by using said detection result, and 
 acquiring digital data expressed by a two-dimensional Cartesian coordinate system by using a relative illumination distribution of said illumination spot, and said digital data expressed by the (r, θ) coordinate system by a processing unit. 
 
     
     
       7. A The method according to  claim 6 , wherein said relative illumination distribution is expressed by the two-dimensional Cartesian coordinate system. 
     
     
       8. A The method according to  claim 6 , further comprising:
 acquiring a position of said anomaly on said two-dimensional Cartesian coordinate system. 
 
     
     
       9. A The method according to  claim 6 , further comprising
 changing an optical condition of said illumination of light; 
 storing a plurality of relative illumination distributions corresponding to a plurality of optical conditions; and 
 selecting a relative illumination distribution corresponding to said changed optical condition from said relative illumination distributions. 
 
     
     
       10. A The method according to  claim 6 , further comprising:
 correcting a tilt of said anomaly. 
 
     
     
       11. The inspection apparatus according to claim 1, further comprising:
 an imaging unit which acquires said relative illumination distribution.   
     
     
       12. The inspection apparatus according to claim 1, wherein digital data of said anomaly is acquired by comparing output from said detection unit with a predetermined threshold value. 
     
     
       13. The inspection apparatus according to claim 1, wherein said relative illumination distribution is two-dimensional matrix data. 
     
     
       14. The inspection apparatus according to claim 1, wherein said two-dimensional Cartesian coordinate system is defined by a first axis which connects a rotation center of said substrate with a center of the illumination spot, and a second axis which substantially crosses said first axis at a right angle. 
     
     
       15. The method according to claim 1, wherein said two-dimensional Cartesian coordinate system is defined by a first axis which connects a rotation center of said substrate with a center of the illumination spot, and a second axis which substantially crosses said first axis at a right angle. 
     
     
       16. The method according to claim 6, further comprising:
 acquiring said relative illumination distribution by using an imaging unit.   
     
     
       17. The method according to claim 6, further comprising:
 comparing output from said detection unit with a predetermined threshold value to acquire digital data of said anomaly.   
     
     
       18. The method according to claim 6, wherein said relative illumination distribution is two-dimensional matrix data.