| 摘要 |
PROBLEM TO BE SOLVED: To precisely detect the state of grinding in a grinding process. SOLUTION: A sensor head 1 is connected to a light projection part 2 and a light receiving part 3 respectively through optical fibers 11 and 12 to fetch reflected light from a wafer while irradiating the surface 30 of the wafer ground presently with light. A diffusion plate 15 is arranged at the entrance of a light receiving fiber 12 and the reflected light from the wafer is unformed by this plate 15 and reaches the part 3 through the fiber 12. A spectroscopic filter 18 the light transmissivity of which is varied along a lengthwise direction L and a line CCD 19 for splitting the light transmitting this filter 18 into prescribed wavelength units to receive them are arranged at the part 3. Within a controller, the spectroscopic waveform of the reflected light generated by the CCD 19 is compared with criterion data, thereby discriminating the propriety of the advancing state of grinding and a time for finishing grinding. |
