| 摘要 |
PROBLEM TO BE SOLVED: To measure the thickness of a film to be measured over a wide measuring range regardless of the characteristics and thickness of the film by irradiating the periphery of the step between the film and a substrate with light set at a prescribed angle of incidence and detecting the size of a gap formed on a surface receiving reflected light. SOLUTION: The surfaces of a transparent resist film 3 to be measured formed on a substrate 2 and the substrate 2 are irradiated 8 with infrared laser light projected upon the surfaces at an angleθof incidence set so that the laser light can be reflected totally from the surfaces and reflected laser light from the periphery of the step D1 between the film 3 and substrate 2 is received with a CCD element 11 incorporated in a CCD camera 9. The image pickup signal of the element 11 is inputted to a computer 10 through a cable 12. When the laser light is projected, the laser light is not reflected from the part corresponding to a nonirradiated part around the step D1 and, as a result, a gap is formed at part of the light receiving surface of the element 11. The computer 10 measures the size of the gap based on the image pickup signal and calculates the thickness of the film 3 from the size of the gap.
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