Radiant energy – Photocells; circuits and apparatus – Optical or pre-photocell system
Patent
1987-06-23
1989-04-18
Westin, Edward P.
Radiant energy
Photocells; circuits and apparatus
Optical or pre-photocell system
250201, 250227, 356375, G01B 1100
Patent
active
048230146
ABSTRACT:
A position detecting device, usable in a projection exposure apparatus for optically projecting a pattern of a reticle upon a wafer by use of a projection lens system, for detecting the position of the wafer with respect to an imaging plane of the projection lens system is disclosed. The position detecting device includes a light source from which light is projected upon the surface of the wafer. The light reflected by the wafer surface is converted by a photoelectric converting element into an electric signal, on the basis of which the position of the wafer is detected. Upon the projection of the position detecting light, the light is controlled by an optical integrated-circuit such as an optical waveguide type element. This allows, with a simple and compact structure, the irradiation of the wafer surface with lights of different wavelengths from plural light sources and/or the irradiation of different locations on the wafer surface with the light.
REFERENCES:
patent: 4230940 (1980-10-01), Minami et al.
patent: 4363962 (1982-12-01), Shida
patent: 4692611 (1987-09-01), Hoogenboom
patent: 4698513 (1987-10-01), Tojo et al.
patent: 4723845 (1988-02-01), Mizutani et al.
Canon Kabushiki Kaisha
Westin Edward P.
LandOfFree
Position detecting device usable with an object having a surface does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Position detecting device usable with an object having a surface, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Position detecting device usable with an object having a surface will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2398344