| 摘要 |
PROBLEM TO BE SOLVED: To measure the flatness on the surface of an object to be inspected surely by a method wherein the surface of the object to be inspected is irradiated with a plurality of laser beams from a plurality of optical fibers arranged in a prescribed state in such a way that the laser beams are converged in one point at the rear of the object to be inspected and the state of the beams reflected on the surface of the object to be inspected is inspected. SOLUTION: A plurality of optical fibers 4 in a light irradiation part 2 are arranged in such a way that laser beams 3 emitted from their beam radiation ends are condensed toward a certain point 7 and that the beam radiation ends become a square state at uniform intervals. The laser beams 2 which are emitted from the beam irradiation part 2 are reflected on a face 1a, to be inspected, at a wafer 1 so as to be incident, as reflected beams 3', on a CCD camera as a photodetector 8. A spreading angleθis set in such a way that all the reflected beams 3' can be detected. An image which is obtained by the photodetector 8 by irradiating the laser beams 3 from the optical fibers 4 is a regular image when the wafer 1 is flat. When a warpage or an irregularity exists on the wafer 1, the reflected beams 3' are inclines, and the image is distorted.
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