Abstract: In a position detecting apparatus having an object optical system, two beams are generated for irradiating a diffraction grating formed on an object from two directions at a predetermined intersect angle for forming an interference fringe, the beams passing through a pupil plane of the object optical system spaced apart a predetermined distance from each other. An opto-electric detector receives diffracted light from the grating via the object optical system and outputs a detection signal, and the position of the object is determined on the basis of the detection signal. An adjustable optical member provided in a light path between an optical source and the object changes incident angles at which the two beams are incident on the grating while keeping the intersect angle between the two beams substantially constant.

Abstract: A position detecting apparatus comprises a double-beam producing device for producing two beams different in frequency from each other, which are guided to irradiate a diffraction grating on an object to be inspected in two predetermined directions, and a detector photoelectrically detecting through an objective optical system diffracted light produced by the diffraction grating, in which the double-beam producing device comprises a light source for supplying a beam of a single wavelength or multiple wavelengths, a beam splitting device for splitting the beam from the light source into two predetermined beams, a relay optical system for converging the two split beams at a predetermined position, and a frequency difference producing device disposed at or near a converging position by the relay optical system, for producing a predetermined frequency difference between the two split beams.

Abstract: An apparatus for detecting the position, in a predetermined direction normal to a substrate, of at least one measurement point in a detection area on the substrate, includes:a projection device for projecting a light-dark pattern consisting of a repetitive pattern of light and dark portions in a predetermined detection direction onto substantially the entire detection area;a photoelectric detection device for detecting reflection light from the substrate, and outputting a photoelectric signal having a waveform representing the contrast of an image of the light-dark pattern in the detection direction;a device for detecting the position of a waveform representing a dark portion of the light-dark pattern corresponding to the measurement point in the waveform of the photoelectric signal; anda measurement device for measuring the position, in the predetermined direction, of the measurement point based on a deviation between the detected waveform position and a predetermined reference position.

Abstract: An aligning device for aligning a substrate with a predetermined point on the basis of a detection signal from a photoelectric detector uses interference light generated by light diffracted from a diffraction grating. A calculating device calculates at least one of a crossing angle of two coherent beams irradiating the grating and the rotational error of a crossing line between a plane containing principal rays of the beams and the surface of the substrate, with respect to the direction of arrangement of the grating, based on the phase difference between detection signals of the photoelectric detector corresponding to interference light generated from different portions of the crossing area. The output of the calculating device may be used to adjust the crossing angle and/or to correct the rotational error.

Abstract: This invention intends to provide a catadioptric reduction projection optical system of a construction in which an on-axis light beam is used in a catadioptric system and resolving power is prevented from being deteriorated, and more particularly a catadioptric reduction projection optical system having a first lens unit G1 of negative refractive power for diffusing a light beam from a reticle 1, a semi-transparent mirror 5 for transmitting therethrough the light beam from the first lens unit G1, plane parallel plates 2, 3 and 4 disposed obliquely with respect to the optical axis between the first lens unit G1 and the semi-transparent mirror 5 for correcting aberrations attributable to the semi-transparent mirror 5, a concave reflecting mirror 7 for returning the light beam emerging from the semi-transparent mirror 5 to the semi-transparent mirror 5 while converging the light beam, and a second lens unit G3 of positive refractive power for converging the light beam returned to the semi-transparent mirror 5 an

Abstract: An apparatus for detecting a focussing position in a projection exposure system. The apparatus constitutes a detection system for causing the so-called automatic focussing apparatus to operate more precisely with greater reliability and the focussing height at the respective portions of a mask pattern are separately determined, thereby making the accurate discrimination of the focussing position even in cases where any special mark is not used or the intentity of the exposure light is varied moment by moment.

Abstract: In a cata-dioptric optical system having a combination of a reflection system and a refraction system for reduction-projecting an object on a first plane onto a second plane, a polarization beam splitter and a quarter wavelength plate are provided to split the incident light and the reflected light. The light beam directed to the polarization beam splitter is converted to a substantially collimated light beam by a first group of lenses. A second group of lenses are arranged between the polarization beam splitter and a concave reflection mirror to diverge the light beam. The light reflected by the concave reflection mirror is directed back to the polarization beam splitter with a substantially collimated state by the second group of lenses. The light beam from the second group of lenses transmitted through the polarization beam splitter is focused by a third group of lenses having a positive refraction power to form a reduced image.

Abstract: An absolute value arithmetic circuit for computing the absolute value of two binary input signals, includes: a computing circuit for obtaining a difference between the two input signals, a 1's complementor for non-inverting or inverting an output from the computing circuit in accordance with a positive sign bit or a negative sign bit of the output, a priority encoder for searching an output from the 1's complementor for the position of a first "0" bit from the least significant digit of the output and delivering an encoder output indicating the position of the first "0" bit, and a bit inverting circuit for inverting and delivering a bit row from the least significant digit bit to the "0" bit in the output from the 1's complementor in accordance with the encoder output, and directly delivering a bit row from a bit higher than the "0" bit to the most significant digit bit of the output without inverting them.

Abstract: In an alignment device, irradiation means irradiates two coherent beams, having a predetermined wavelength, to a first diffraction grating formed on a mask and a second diffraction grating formed on a photosensitive substrate via an object optical system in such a manner as to cross with each other at a predetermined angle on one of the first and second diffraction gratings. First light receiving means photoelectrically detects interference light of diffracted rays produced substantially in the same direction from the one diffraction grating. A third diffraction grating is disposed in a plane substantially conjugate to the one diffraction grating, and second light receiving means photoelectrically detects interference light of diffracted rays produced by the third diffraction grating from diffracted rays of the two beams which are diffracted by the other of the first and second diffraction gratings and impinged upon the third diffraction grating at a predetermined incident angle via the object optical system.

Abstract: The device is of the type used for semiconductor exposure apparatus equipped with a projection lens for transferring a pattern, formed on a reticle, onto a substrate with an exposure light. The device is adapted for detecting the position of an alignment mark formed on the substrate. The device includes light irradiation means, detector, an irradiation light correcting optical element and a detection light correcting optical element. The light irradiation means irradiates the alignment mark, through the projection lens, with alignment light having a wavelength different from that of the exposure light. The detector detects, through the projection optical system, light from the alignment mark.

Abstract: A projection exposure apparatus comprises a projection optical system for forming an image of a predetermined pattern on a mask onto a photosensitive substrate under exposure light having a first wavelength, an illumination system for illuminating a mask on the photosensitive substrate with light having a second wavelength different from the first wavelength through the projection optical system so as to attain alignment, and a detection system for detecting light reflected by the mark. The illumination system comprises a light source for emitting the light having the second wavelength, a first field stop for defining an illumination field on the photosensitive substrate and a second field stop for defining an illumination field on the photosensitive substrate.

Abstract: A position detection apparatus has a substrate on which a diffraction grating is formed and an alignment optical system for illuminating the diffraction grating with a pair of coherent light beams having different frequencies from each other from different directions. The intensity of interference fringes formed due to the interference of diffracted beams generated in the diffraction grating is detected photo-electrically. The alignment optical system forms the pair of coherent light by using an optical modulator, and two luminous fluxes from the optical modulator pass through independent optical paths positioned symmetrically with the optical axis of the alignment optical system therebetween and reach the diffraction grating from different directions. The alignment optical system has a stop having an opening having an inclined edge with respect to the direction of the grating components of the diffraction grating, the opening being in conjugation with the substrate.

Abstract: There is disclosed an apparatus for transferring a reticle pattern onto a wafer, in which the reticle and the wafer are mutually aligned by irradiating an alignment mark of the wafer with light beams and detecting the optical information from the mark. Depending on the shape of the wafer mark, suitably selected is a first light beam passing through the center of entrance pupil of an objective optical system, or a pair of second light beams passing through the entrance pupil point-symmetrically with respect to its center. The wafer mark consists of a main mark and an auxiliary mark, and the main mark contains a diffraction grating pattern. The second paired light beams and the main mark are used for determining the positional error within an integral fraction of the pitch of the diffraction grating pattern, and the first light beam and the auxiliary mark are used for determining the positional error of an integral multiple of the pitch of the diffraction grating pattern.

Abstract: An alignment apparatus is provided with a first beam receiving device arranged to receive an interference beam which is produced at a diffraction grating of a substrate as a result of illumination with a pair of beams which intersect each other on the substrate, and a second beam receiving device arranged to receive a reference beam which is produced by the interference between regularly reflected beams of the pair of beams occurring on the substrate, wherein the positional offset of the substrate is obtained on the basis of a comparison between the output signal of the first beam receiving device and the output signal of the second beam receiving device. Since a beam transmitting path for transmitting a measurement beam is substantially common to a beam transmitting path for a reference beam, even if the fluctuations of air occur, both the measurement beam and the reference beam substantially equally reflect the influence of the fluctuations, whereby it is possible to cancel the same.

Abstract: A position detection apparatus has a substrate on which a diffraction grating is formed and an alignment optical system for illuminating the diffraction grating with a pair of coherent light beams having different frequencies from each other from different directions. The intensity of interference fringes formed due to the interference of diffracted beams generated in the diffraction grating is detected photo-electrically. The alignment optical system forms the pair of coherent light by using an optical modulator, and two luminous fluxes from the optical modulator pass through independent optical paths positioned symmetrically with the optical axis of the alignment optical system therebetween and reach the diffraction grating from different directions. The alignment optical system has a stop having an opening having an inclined edge with respect to the direction of the grating components of the diffraction grating, the opening being in conjugation with the substrate.

Abstract: A device for detecting the levelling of an object disposed on a plane substantially perpendicular to the optic axis of main objective optical means and worked by a radiation beam from the main objective optical means comprises levelling detecting optical means including an irradiating optical system for supplying a collimated light beam to a particular area of the surface of the object from an oblique direction, and a condensing optical system having light receiving means and for condensing the light beam reflected by the particular area on the light receiving means, and field stop means providing a plurality of stop openings differing in shape from one another, the field stop means being disposed in the levelling detecting optical means, one stop opening corresponding to the shape of the particular area being selected from among the plurality of stop openings.

Abstract: An apparatus for detecting the level of an object surface comprises a light source for supplying a light beam obliquely incident on the object surface, an imaging optical system provided to image the light beam reflected by the object surface, a light-receiving element having a detecting surface coincident with the imaging plane of the imaging optical system and determining the level of the object surface on the basis of the position of the image of the light beam on the detecting surface, and polarization correcting optics provided on an optical path leading from the light source via the object surface to the detecting surface for adjusting the intensity ration between the two mutally orthogonal polarized light components of the light beam.

Abstract: A projection optical apparatus comprises a projection optical system for projecting the image of an object onto a substrate, data collecting means for obtaining data regarding a factor which causes a variation in the optical characteristic of the projection optical system, adjusting means for adjusting the relation between the substrate and the image of the object relative to the variation in the optical characteristic of the projection optical system, means for determining the amount of adjustment by the adjusting means in accordance with a model formula using a predetermined parameter on the basis of the data obtained by the data collecting means, means for independently measuring the variation in the optical characteristic of the projection optical system, and means for correcting the parameter of the model formula on the basis of the result measured by the measuring means.

Abstract: A projection exposure apparatus includes illuminating means for applying energy rays to a mask having a predetermined pattern formed thereon, a projection optical system for forming the image of the pattern in a predetermined projected state on a responsive substrate, adjusting means for correcting the fluctuation of the projected state of the image caused by the passage of the energy rays, exposure control means for controlling the energy rays so that the pojected image of the pattern by the projection optical system is transferred onto the responsive substrate under a predetermined exposure condition, means for making information regarding the reflectivity of the responsive substrate, and main control means for controlling the adjusting means on the basis of the predetermined exposure condition of the exposure control means and the information regarding the reflectivity.

Abstract: A surface displacement sensor is so designed that a stop or aperture for controlling an angle of opening is disposed at the position of a pupil of a detection optical system in which a slit image is focused on the surface to be detected and the light rays reflected from the surface to be detected are collected to re-focus the slit image on the light receiving surface of the sensor. When the height position of the surface to be detected is detected by such stop for controlling the angle of opening, the deviation of the distribution of intensity of light which tends to occur in the widthwise direction of the slit through which passes the light beam which in turn focuses a slit image, can be positively decreased by limiting the angle of opening N.A. in the widthwise direction of the slit for passing the light beam to focus a slit image to be narrow and consequently the degree of detection accuracy can be improved.