PURPOSE: To make it possible to detect a flaw having unevenness and a flaw changing only in reflectivity, by using not only illumination beam allowed to obliquely irradiate an object to be inspected but also illumination beam having a spot diameter near to a diffraction limit and allowed to vertically irradiate the object to be inspected.
CONSTITUTION: The semiconductive laser beam from a beam source 20 is allowed to obliquely irradiate an object 25 to be inspected. When there is a flaw on the object 25 to be inspected, the illumination beam is scattered to be guided to a beam detector 41 and condensed thereto to be converted to a flow detection signal A. The remaining scattered beam is guided to a shaping circuit 46 to be converted to a flaw detection signal C. The beam from a beam source 30 is focused to the object 25 to be inspected and a part of the reflected beam thereof is guided to a focus error drive circuit 42 and the illumination beam from the beam source 30 is controlled by the output signal of said circuit 42 so as to be always focused to the object 25 to be inspected. Reflected beam is guided to shaping circuits 44, 43 to be respectively converted to flaw detection signals B', B. By this method, both or either one of a flaw having unevenness and a flaw changing in reflectivity can be detected by the same apparatus and detection accuracy is also enhanced.
MOMOO KAZUO
SO KOJI
SHIOZUKA KAZUMASA
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