Surface inspection method and surface inspection apparatus

Abstract

A surface inspection apparatus capable of acquiring scattered light intensity distribution information for each scattering azimuth angle, and detecting foreign matters and defects with high sensitivity. A concave mirror for condensation and another concave mirror for image formation are used to cope with a broad cubic angle. Since mirrors for condensation and image formation are used, a support for clamping the periphery of a lens is unnecessary, and an effective aperture area does not decrease. A plurality of azimuth-wise detection optical systems is disposed and reflected light at all azimuths can be detected by burying the entire periphery without calling for specific lens polishing. A light signal unification unit sums digital data from a particular system corresponding to a scattering azimuth designated in advance in the systems for improving an S/N ratio.

1 . A surface inspection method by irradiating light to a predetermined position on a surface of an inspection object to form an illumination spot, detecting light scattered, diffracted and reflected from said illumination spot, and detecting foreign matters and defects existing on the surface of said inspection object or in the proximity of, and inside, the surface, said method comprising the steps of:
 condensing and reflecting the light scattered, diffracted and reflected from said illumination spot by a plurality of condensation concave mirrors arranged at a plurality of azimuth angles with respect to the surface of said inspection object, respectively;   reflecting light reflected from each of said condensation concave mirrors arranged at a predetermined positional relationships with each of a plurality of image formation concave mirrors arranged at a higher angle of elevation than said condensation concave mirror with respect to the surface of said inspection object for each of said plurality of azimuth angles;   distinguishing and detecting light reflected by said plurality of image formation concave mirrors; and   detecting foreign matters and defects existing on the surface of said inspection object or in the proximity of, and inside, the surface of said inspection object on the basis of the light detected.   
     
     
         2 - 25 . (canceled)