| 摘要 |
An endpoint detector for plasma etching comprises a photo detecting section for receiving an emission spectrum of plasma due to etching gas from a process chamber for providing plasma etching to a processing object so as to detect a specific waveform of the received emission spectrum, a calculating section for detecting an endpoint of an etching process based on a detecting signal sent from the photo detecting means, the photo detecting section comprises a first optical system for detecting light having a specific wavelength from the emission spectrum received from the process chamber so as to be photoelectrically transferred, and a second optical system for detecting a part of the emission spectrum so as to be photoelectrically transferred before light having a specific wavelength is extracted from the emission spectrum by the first optical system, and the calculating section reduces drift of an electrical signal, which is based on light having a specific wavelength extracted from the first optical system, based on an electrical signal, which is based on light extracted from the second optical system, so as to detect the endpoint of the etching process.
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