Optics: measuring and testing – For size of particles – By particle light scattering
Patent
1986-03-27
1990-02-20
Rosenberger, Richard A.
Optics: measuring and testing
For size of particles
By particle light scattering
356237, G01N 2101
Patent
active
049021311
ABSTRACT:
A novel technique suitable for inspection or examination of the surface condition of a substrate such as a semiconductor wafer. First is one irradiates a light e.g. a laser beam on a substrate surface to focus a scattered light therefrom. Next detects the scattered light focused e.g. with a photomultiplier tube, thus to inspect the substrate surface. When the detection of the scattered light is thus carried out, correction means e.g. a circuit for controlling a voltage applied to the photomultiplier tube, a filter having a variable light-screening factor, a movable iris or an amplification factor adjustment circuit etc. is used to correct the detection sensitivity in accordance with the reflectivity of the substrate surface. Practically, such a corrective operation is carried out on the basis of the intensity of a scattered light or a regularly reflected light from the substrate surface. Further, it may be possible to obtain a signal for control of the corrective operation by averaging signals detected when the substrate surface is subject to scanning of an irradiating light. Thus, this surface inspection technique can detect particles attached on the substrate surface always utilizing the same slice level and the same sensitivity even when substrates having different indices of reflection are employed.
REFERENCES:
patent: 3229564 (1966-01-01), Meltzer
patent: 3340400 (1967-09-01), Quittner
patent: 4285597 (1981-08-01), Lamprecht et al.
patent: 4352017 (1982-09-01), Duffy et al.
patent: 4360275 (1982-11-01), Louderback
Preprint of 32nd Lectures of the Japan Society of Applied Physics, 29a--A--3 "Development of Dust Detecting Apparatus; Detection of Dust on a Wafer with Thin Film", Yamazaki et al., published Mar. 29, 1985.
Miyoshi Motosuke
Ogawa Shigeru
Okumura Katsuya
Yamazaki Yuichiro
Kabushiki Kaisha Toshiba
Rosenberger Richard A.
LandOfFree
Surface inspection method and apparatus therefor does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Surface inspection method and apparatus therefor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Surface inspection method and apparatus therefor will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1612403