Abstract: A double-conjugate maintaining optical system for maintaining the conjugate relation between an object and its image even if the distance between the object and the image varies and also maintaining another set of conjugate relation in a predetermined condition includes an afocal system comprising a plurality of lens units, a first positive lens unit disposed on the object side of the afocal system, and a second positive lens unit disposed on the image side of the afocal system. The first positive lens unit is movable relative to the second positive lens unit so that the object is positioned on the focal plane of the first positive lens unit opposite to the afocal system. The afocal system is movable along the optical axis thereof in a predetermined relation with the first positive lens unit.

Abstract: An alignment apparatus for aligning one of the substrates with the other by means of first and second reference marks comprises scanning means including a light beam generating means for reciprocally scanning first and second areas respectively by a light beam, discrimination means for generating a discrimination signal indicative of the scanning direction by the scanning means in synchronism with the scanning, first photoelectric means for generating a first signal when the first photoelectric means receives the light beam transmitted through a first area and separated by the first reference mark, second photoelectric means for generating a second signal when the second photoelectric means receives the light beam transmitted through the second area and separated by the second reference mark, operation means for determining the direction and amount of the relative deviation between the first and second reference marks from the first and second signals and from the discrimination signal, and means for moving o

Abstract: A method for positioning an object with patterns being formed thereon, employs a first device for extracting first information relative to patterns in a first region on the object, a second device for extracting second information relative to patterns from a second region including the first region on the object, an operating circuit to calculate a degree of coincidence between the first information and the second information, and a detecting circuit for detecting a position of the first region in the second region, whereby the position of the object can be reproduced with high reproducibility in accordance with the position as detected.

Abstract: An exposure apparatus for production of ICs of the type that includes a stage on which is placed a semiconductor wafer to be exposed by illumination light projecting means, and means for two-dimensionally moving the stage within a plane intersecting the illumination light at substantially right angles. The improvement comprises illumination detection means provided with a photo reception surface, and means for mounting the illumination detection means on the stage in such a manner that the photo reception surface and the surface of the semiconductor wafer on the stage to be exposed are at substantially equal height relative to the stage.

Abstract: A positioning apparatus includes a projecting means for projecting plural coherent light beams onto an object to be aligned. The projecting means comprises plural converging means for forming each coherent light beam into a stripe-shaped beam extended in a direction substantially perpendicularly to the scanning direction of said scanning means, and each of said alignment marks comprises plural short line segments arranged in a stripe extended in a direction substantially perpendicular to the scanning direction of said scanning means and each inclined approximately by 45.degree. with respect to said scanning direction. Therefore, the alignment mark can be clearly identified from the circuit patterns by relatively rough preliminary alignment even if such mark is positioned in a narrow space between the chips for example for LSI.

Abstract: An alignment device in an IC projection exposure apparatus includes a projection lens system for viewing to a wafer surface having a reference mark comprising a periodic pattern structure having a predetermined period in one direction and a mask surface having a reference mark to be position-adjusted with respect to the reference mark of the wafer, the projection lens system being capable of forming an image of an observation light source on the wafer surface through the mask surface, and an observation optical system for detecting the reflected light from the wafer surface passed through the projection lens system. The device further includes means for selecting a particular component of the diffracted light from the wafer surface formed by the pattern of the reference mark on the wafer, and for directing the particular component to the observation optical system.