| 摘要 |
PURPOSE:To measure the irregular condition on the surface of a photosensitive substrate accurately over a wide range thereof through a simple constitution. CONSTITUTION:A part L2 of a laser beam L emitted from a laser light source 12 in an interferometer 4 for measuring the coordinate is split into an S polarized laser beam L3 and a P polarized laser beam L4. The laser beam L3 is further split through a half prism 21 into a measuring beam L5 and a reference beam L6. The measuring beam L5 is projected through a polarized beam splitter 23, an objective lens 9, etc., onto a plate 2. The height in Z direction of the plate 2 is then detected based on the interfering light of the measuring beam L5 and the reference beam L6. The laser beam L4 is projected through a half mirror 30, the polarized beam splitter 23, the objective lens 9, etc., onto the plate 2 and the light reflected t on the plate 2 is received by a photoelectric detector 33. |
