| 摘要 |
PROBLEM TO BE SOLVED: To provide a measuring device for wafer thickness unevenness using an optical heterodyne interference measuring device, capable of measuring the surface and back displacement without being influenced by the inclination and warpage of the wafer. SOLUTION: This measuring device for wafer thickness unevenness has a table, on which a wafer is placed and an optical measuring device for applying laser beam to the wafer, in which the wafer or a measuring optical system is relatively moved to scan the wafer by laser beam to measure the wafer thickness unevenness. In this device, the optical measuring device includes a projection system for applying inclined laser beam to the wafer, and a corner cube for receiving reflected light from the wafer to be reflected to return to the irradiation position, in which a detector for receiving length measuring light is disposed in the range of receiving beams of reflected light from the corner cube.
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