摘要 |
An interfacial position measuring method for a substrate internally having a plurality of interfaces parallel to one another. A light-convergent line which has converged in only a one-axis direction out of parallel light having an optical axis vertical to the substrate surface is formed so as to be inclined with respect to the substrate surface, and the light-convergent line is made to intersect with the substrate. Out of reflected light of the light-convergent line reflected by the substrate, a position having a light intensity peak is taken as an interface, by which a plurality of interfaces inside the substrate can be measured simultaneously and high-speed interfacial position measurement can be achieved.
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