Patent ID: 7172675
Filing Date: 2007-02-06
Classification: H01J,H01L

Abstract:
1. A plasma processing apparatus comprising: (a) an observation window installed at a sidewall of a processing room thereof, the observation window comprising: (b) a laser irradiating unit at a side of the observation window opposite the processing room, the laser irradiating unit irradiating a laser light into the processing room through the observation window; and (c) a laser detecting unit detecting a reflected light or a scattered light through the observation window, the reflected light or the scattered light being generated when the laser light irradiated into the processing room is irradiated to floating particles in the plasma, wherein the observation window has a surface having a curvature substantially the same as that of an inner wall of the processing room; a first end of the hole adjoining the transparent member has a height corresponding to about 1.5° when viewed at an observation target location in the processing room; and the height of the opening of a second end of the hole facing the processing room is smaller than that of the first end, wherein the observation target is located near a perimeter of a holder of a wafer to be processed at a farther end of the wafer to be processed with respect to the observation window.