Projection exposure apparatus and projection exposure method
First Claim
1. A projection exposure apparatus comprising a stage for holding an exposure illumination system, selected one of a mask and a reticle, a projection optical system and an object of exposure, an alignment system for detecting relative positions of selected one of the mask and the reticle and the object of exposure thereby to control the positioning thereof, at least one irradiation means for converting the light emitted from a coherent light source into a parallel irradiation light beam and irradiating the same light diagonally on the exposure area of the projection optical system on the surface of the object of exposure at an incident angle of θ
- , at least a detection optical system for introducing the objective light reflected on the object of exposure to pattern detection means, means for separating the light emitted from the coherent light source and generating a reference light, at least one reference light means for introducing the reference light to the pattern detection means and superposing and causing an interference thereof with the optical axis of the objective light at a desired angle on the pattern detection means, a processing circuit for producing at least information on an inclination of the object of exposure from the information on the interference pattern obtained from the pattern detection means, and a stage control system for controlling at least a unidirectional inclination of the object of exposure on the basis of the same information.
1 Assignment
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Accused Products
Abstract
A projection exposure apparatus (1) comprises an incident light optical system for causing the light emitted from a light source 1 to enter an object of exposure (4) in diagonal direction, a detection apparatus (3) for causing an interference between the light reflected from the object of exposure (4) and a reference light and detecting the resultant interference fringe, a processing circuit for determining the inclination and height of the surface of the object of exposure (4) from the optical information on the interference fringe, and a stage (7) for supporting the object of exposure (4). The object of exposure (4) is subjected to projection exposure by driving the stage (7) according to the calculated inclination and height of the object of exposure (4).
46 Citations
63 Claims
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1. A projection exposure apparatus comprising a stage for holding an exposure illumination system, selected one of a mask and a reticle, a projection optical system and an object of exposure, an alignment system for detecting relative positions of selected one of the mask and the reticle and the object of exposure thereby to control the positioning thereof, at least one irradiation means for converting the light emitted from a coherent light source into a parallel irradiation light beam and irradiating the same light diagonally on the exposure area of the projection optical system on the surface of the object of exposure at an incident angle of θ
- , at least a detection optical system for introducing the objective light reflected on the object of exposure to pattern detection means, means for separating the light emitted from the coherent light source and generating a reference light, at least one reference light means for introducing the reference light to the pattern detection means and superposing and causing an interference thereof with the optical axis of the objective light at a desired angle on the pattern detection means, a processing circuit for producing at least information on an inclination of the object of exposure from the information on the interference pattern obtained from the pattern detection means, and a stage control system for controlling at least a unidirectional inclination of the object of exposure on the basis of the same information.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 45)
- 21. A method of detecting at least an inclination of an optically multi-layered object, wherein regularly reflected light is caused to interfere with a fixed reference light coherent with said regularly reflected light and obtaining at least a pitch of interference information, and detecting at least the inclination of the multilayered object from the pitch of the interference information.
- 25. An apparatus for detecting selected at least one of the inclination and height of an optically multilayered object comprising a light source, irradiation means for irradiating the light emitted from the light source on the surface of an object of measurement having an optically multilayered structure in such a manner that the main beam of the light enters the surface at an incident angle of at least 85 degrees, means for detecting the information on the light reflected regularly from the object of measurement, and a processing circuit for introducing inclination of the object of measurement from the signal obtained at the detection means, and further comprising reference light generation means for generating a fixed reference light coherent with said regularly reflected light, said regularly reflected light and the reference light being detected in the form of interference fringe by the detection means, the processing circuit introducing the inclination from a pitch of an interference signal thus obtained.
- 27. An apparatus for detecting selected at least one of inclination and height by interference, comprising at least one monochromatic light source for emitting a beam having a plurality of different wavelengths, collimating means for converting the beam emitted from the monochromatic light source into a substantially parallel beam, a beam splitter for separating the beam into a plurality of beams, irradiation optical means for irradiating on an optically multilayered object one of the parallel beams into which the original beam is splitted, a detection optical system for introducing the objective light irradiated by the irradiation optical means and reflected on the optically multilayered object to a detector, a reference light optical system for introducing to the detector the other of the parallel beams into which the original beam is splitted by the beam splitter, said other parallel beam being superposed at the detector on the objective light obtained from the detection optical means, and selective detection means for selecting any of a plurality of information signals on the interference fringes detected by the detector in accordance with the wavelengths thereby to detect the inclination of the optically multilayered object.
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36. An exposure apparatus of reduction projection (compression projection) type for subjecting a substrate to a step-and-repeat process so that a circuit pattern formed on a mask through a reduction projection lens is exposed by reduction projection on the substrate, the apparatus comprising at least one light source for emitting a beam having a plurality of different wavelengths, collimating means for converting the beam emitted from the light source into a substantially parallel light beam, a beam splitters for separating the light beam into a plurality of beams, irradiation optical means for irradiating on the substrate one of the parallel beams into which the original beam is splitted by the beam splitter, through the gap between the reduction projection lens and the substrate, a detection optical system for introducing to a detector the objective light reflected by the irradiation reflection means on the substrate, through the gap between the reduction projection lens and the substrate, a reference light optical system for introducing to the detector the other of the parallel beams into which the original beam is splitted by the beam splitter, and superposing the other parallel beam at the detector on the objective light obtained by the detection optical system, and selective detection means for selecting any of a plurality of information signals on the interference fringe detected by the detector and detecting the partial inclination of the substrate, in accordance with the light beams having a plurality of wavelengths.
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37. A method of exposure by reduction projection for subjecting a substrate to a step-and-repeat process so that a circuit pattern formed on a mask through a reduction projection lens is exposed on the substrate by reduction projection, wherein a beam having a plurality of different wavelengths emitted from a light source is separated into a plurality of substantially parallel beams, one of the parallel beams thus obtained is irradiated on the substrate through the gap between the reduction projection lens and the substrate, an objective light beam reflected on the substrate is introduced to a detector through the gap between the reduction projection lens and the substrate, the other of the parallel beams obtained by separation is introduced to the detector and superposed on the objective light at the detector, and any of a plurality of information signals on the interference fringe detected by the detector is selected, thereby detecting selected at least one of the partial inclination and height of the substrate.
- 38. A method of detecting selected at least one of inclination and height, wherein a coherent light is irradiated on an object of measurement, the information on an interference fringe generated by the light reflected from the object of measurement and a reference light interfering with the coherent light is detected, the information derived at least one of only from the light reflected from the object of measurement and only from the reference light is collected, the information thus collected is corrected with reference to the detected information on the interference fringe, the information on selected one of the pitch of the interference fringe and the pitch and phase thereof is calculated from the corrected information on the interference fringe, and selected one of the inclination and height of the object of measurement is detected on the basis of the calculated information on selected one of the pitch of the interference fringe and the pitch and phase thereof.
- 43. An apparatus for detecting selected at least one of inclination and height comprising first irradiation means for irradiating a coherent light on an object of measurement, second irradiation means for irradiating a reference light interfering with the coherent light, interference fringe information detection means for detecting the information on an interference fringe generated from the reflected light obtained from the object of measurement by the light irradiated from the first irradiation means on the one hand and the reference light irradiated from the second irradiation means on the other hand, collecting means for collecting the information derived at least one of only from the light reflected from the object of measurement and only from the reference light, correction means for correcting the interference fringe information detected by the interference fringe information detection means by use of the information collected by the collecting means, and detection means for calculating the information on selected one of the pitch of the interference fringe and the pitch and phase thereof from the interference fringe information corrected by the correction means, thereby detecting selected at least one of the inclination and height of the object of measurement on the basis of the calculated information on selected one of the pitch of the interference fringe and the pitch and phase thereof.
- 49. A method of projection exposure in which a circuit pattern formed on a mask is exposed by projection on a substrate through a projection optical system, the method being such that a coherent light is irradiated on the substrate, the information on the interference fringe generated by the light reflected from the substrate and the reference light interfering with the coherent light is detected, the information derived at least one of only from the light reflected from the substrate and only from the reference light is collected, the detected information on the interference fringe is corrected by use of the collected information, the information on selected one of the pitch of the interference fringe and the pitch and phase thereof is calculated from the corrected information on the interference fringe, selected at least one of inclination and height of the substrate is detected on the basis of the calculated information on selected one of the pitch of the interference fringe and the pitch and phase thereof, and at least selected one of the mask and the substrate is inched along the optical axis of the projection optical system and also around the two axes crossing said optical axis in the direction perpendicular thereto, thereby controlling the leveling in such a manner that the image-forming plane of the circuit pattern registers with the substrate surface.
- 57. A projection exposure apparatus in which a circuit pattern formed on a mask is exposed by projection on a substrate through a projection optical system, said apparatus comprising driving means for tilting at least selected one of a mask and a substrate both along the optical axis and around two axes crossing the optical axis of the projection optical system in the direction perpendicular thereto, first irradiation means for irradiating coherent light on the substrate, second irradiation means for irradiating the reference light adapted to interfere with the coherent light, interference fringe information detection means for detecting the interference fringe information generated from the reflected light obtained from the substrate by the light irradiated from the first irradiation means and the reference light irradiated from the second irradiation means, collecting means for collecting the information derived only at least one of from the light reflected from the substrate and from the reference light, correction means for correcting the interference fringe information detected by the interference fringe detection means, by use of the information collected by the collecting means, means for detecting selected one of the inclination and height of the substrate by calculating the information on selected one of the pitch of the interference fringe and the pitch and phase thereof from the information corrected by the correction means, said detection means detecting selected one of the inclination and height of the substrate on the basis of the calculated information on selected one of the pitch of the interference fringe and the pitch and phase thereof, and leveling control means for controlling the driving means in such a manner that the image-forming surface of the circuit pattern registers with the substrate surface, on the basis of the information on selected one of inclination and height detected by the detection means.
Specification