| 摘要 |
PURPOSE:To perform an etching on a wafer stably and with high precision by a method wherein a change in light of a certain wavelength in an emission spectrum of plasma is monitored and the dispersion of the etching ratio is operation-processed from the starting time of etching completion on a part of the wafer and the time of etching completion on the whole surface of the wafer. CONSTITUTION:A unit 9 consists of an interference filter or a spectroscope, which chooses a light with a peculiar wavelength among the emission spectrums in low- temperature plasma, and a photoelectric converter. The starting time of etching completion on a part of a wafer and the time of etching completion on the whole surface of the wafer are operated by an amplification arithmetic unit 10 using the output of the unit 9 as the input, the operation-processed signal is recorded in a recorder 11 and the dispersion of the etching ratio is computed by a microcomputer 16 from the two times. According to this constitution, as the dispersion of the etching ratio can be monitored during the time manufacturing actually the wafer, a film thickness measuring instrument becomes unnecessary, and moreover, in case of abnormality of the etching state, the dry etching device feedbacks to return the abnormal etching state to the normal state. As a result, the wafer can be stably manufactured and the wafer performed an etching with high precision can be obtained. |
