| 摘要 |
PURPOSE:To accurately measure the thickness of a film within a short time without rotating a substrate, by diffusing the incident beam from a monochromatic beam source by a concave lens and further converting the same to parallel beam by a lens before condensing the parallel beam to one point on a measuring membrane by a convex lens. CONSTITUTION:The incident beam from He-Ne laser 3 is diffused by a concave lens 20 and subsequently converted to parallel beam by a lens 21 while the parallel beam is condensed to one point on a SiO2 film 1 by a convex lens 22. By this method, incident angle almost ranging from 0 deg.-90 deg. is obtained without rotating a substrate 2. All of the reflected beam from the surface 6 of the SiO2 film 1 and the reflected beam from the boundary surface 7 of the SiO2 film and the Si substrate 2 are received by a photodiode array 4 arranged in a circular arc pattern and the intensities of the reflected beams with respect to the incident angles thereof are detected at once. The luminous intensities detected by the photodiode array 4 are converted to digital signals by an A/D converter 5 and the data thereof are inputted to a microcomputer 8 and the thickness of the film is calculated by the operational processing of said data.
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