Showing papers by "Kenji Saitoh published in 1990"

Position detection method and apparatus

Abstract: A position detecting method for detecting the position of a substrate by use of a grating pattern provided on the substrate includes irradiating the grating pattern with first and second radiation beams having different wavelengths to produce first and second diffraction beams of different wavelengths; and receiving the first and second diffraction beams by use of a sensor to determine the position of the substrate on the basis of the position of incidence of each of the first and second diffraction beams on the sensor.

Position detecting system

Abstract: A position detecting system for detecting the position of a substrate (1, 2) having a surface, with respect to first direction (Z) perpendicular to the surface of the substrate and a second direction perpendicular to the first direction, by use of a mark (3a, 4a) formed on the substrate and having an optical power is disclosed. The system includes a directing device (12) for directing a radiation beam (10a) to the mark so that the radiation beam is deflected by the mark; a sensor (8, 9) for receiving the radiation beam deflected by the mark, wherein the position of the radiation beam incident on the sensor is shiftable in a third direction in accordance with the position of the substrate with respect to the first direction (7) and also is shiftable in a fourth direction, different from the third direction, in accordance with the position of the substrate with respect to the second direction; and a detecting device (102) for detecting the position of the substrate with respect to the first and second directions on the basis of an output of the sensor (8, 9) corresponding to the position of incidence of the radiation beam upon the sensor.