Exposure method and projection exposure apparatus
AssigneeNikon Corporation
InventorKenji Nishi
Life of this patent
Estimating the term…
Abstract
A projection exposure apparatus carries out scan exposure with illumination flux of slit(s) by moving a mask and a substrate in a direction of one-dimension at synchronized speeds with each other. The mask is inclined with a predetermined angle relative to the substrate in the direction of one-dimensional movement. The substrate is also moved in a direction of optical axis of projection optical system when moved in the direction of one-dimension, such that a central part of transfer area on the substrate is located on a best focal plane of projection optical system upon scan exposure.
Claims13
A method for exposure in which a pattern formed in a transfer region on a mask is subject to projection exposure through a projection optical system to be led onto an area to be exposed on a photosensitive substrate, and said mask and photosensitive substrate are at least one-dimensionally, relatively scanned with respect to a projection field of said projection optical system:
- comprising,
- limiting a width of said area of pattern image projected on said photosensitive substrate through the projection optical system to an approximately constant value in a direction of one-dimensional scan;
- and
- inclining a local surface on said photosensitive substrate on which said pattern image is formed, relative to a best focal plane of said projection optical system in the direction of one-dimensional scan.
A projection exposure apparatus comprising:
- a projection optical system for projecting a pattern formed in a transfer region on a mask, onto an area to be exposed on a photosensitive substrate;
- a mask stage for one-dimensionally moving said mask over a region beyond a width of said transfer region in a direction of movement;
- a substrate stage for one-dimensionally moving said photosensitive substrate in the direction of one-dimensional movement of said mask stage at a speed synchronized with a movement speed of said mask stage;
- illumination means for illuminating said mask with an illumination flux for exposure, having a shape between a rectangle and a slit within the projection field of said projection optical system and having an approximately constant width in the direction of one-dimensional movement;
- a substrate holder the holding said photosensitive substrate on said substrate stage with a predetermined inclination angle with respect to the direction of one-dimensional movement of illuminated area formed by said illumination flux on said photosensitive substrate through said mask and said projection optical system;
- holder drive means for moving said substrate holder in a direction of optical axis of said projection optical system such that a central part of said illuminated area on said photosensitive substrate is located near a best focal plane of said projection optical system;
- and
- control means for controlling said holder drive means to maintain an imaging condition of pattern image of said mask on said photosensitive substrate with correspondence to a position in said illuminated area in the direction of one-dimensional movement while scan exposure of pattern of said mask is effected on said area to be exposed.
A scanning exposure apparatus for exposing a shot area defined by street lines on a sensitive surface of a substrate with an image of a pattern of a mask, said apparatus comprising:
- a projection lens having a circular image field to project an image of the pattern of the mask onto the shot area of the substrate;
- a scanning mechanism for one-dimensionally, relatively scanning the mask and substrate with respect to the circular image field of said projection lens at a predetermined velocity ratio corresponding to a magnification of said projection lens in order to perform scanning exposure of said shot area;
- an illumination system for irradiating the mask with radiation having a rectangular distribution which is elongated in a cross-direction of said one-dimensional scan direction and is arranged at a center of a circular object field of said projection lens;
- and
- an adjusting mechanism for adjusting the length of the rectangular distribution of said radiation in accordance with positions of said street lines.
A scanning exposure apparatus for exposing an image of a pattern of a mask onto a shot area defined on a sensitive substrate, said apparatus comprising:
- a double telecentric reduction optical system having a circular image field and being composed only of refraction elements or of a combination of refraction and reflection elements, to project an image of the pattern of the mask onto the shot area of the substrate;
- a scanning mechanism for one-dimensionally, relatively scanning the mask and substrate with respect to the circular image field of said reduction optical system at a predetermined velocity ratio corresponding to a magnification of said reduction optical system;
- an illumination optical system for irradiating the mask with radiation having a rectangular distribution which is elongated perpendicularly to said one-dimensional scan direction and is arranged at a center of a circular object field of said reduction optical system, during the operation of said scanning mechanism;
- and
- a variable aperture mechanism for adjusting the length of the rectangular distribution of said radiation in accordance with the size of said shot area;
- wherein different portions of said shot area are successively scanned by rectangular pattern image portions of the mask.
A scanning exposure apparatus for exposing a predetermined region of a sensitive surface of a plate with an image of a pattern of a mask, said apparatus comprising:
- (a) a double telecentric projection lens for projecting an image of the pattern of the mask onto the region of the plate;
- (b) a scanning mechanism for one-dimensionally, relatively scanning the mask and plate with respect to a circular image field of said projection lens at a predetermined velocity ratio in order to perform scanning exposure of the region of said plate;
- (c) an illumination system for irradiating the mask with radiation having a rectangular shape which is elongated in a cross-direction of the one-dimensional scanning direction and is arranged at the center of a circular object field of said projection lens, whereby a rectangular image portion of the mask pattern is projected toward the plate through said projection lens;
- and
- (d) a focus condition detector for detecting a focus deviation of the surface of said plate relative to a best imaging plane of said projection lens within an area corresponding to said rectangular image portion, during the scanning of said scanning mechanism.
A scanning exposure method in which an image of a pattern of a mask is projected onto a shot area of a photosensitive plate through a projection system, and the mask and plate are at least one-dimensionally, relatively scanned with respect to a field of said projection system, the method comprising the steps of:
- (a) providing a telecentric projection system having a circular image field which is smaller than said shot area and an optical axis which passes through the center of said circular image field;
- (b) limiting an effective imaging area in said circular image field to a diametrically extending rectangular region having a predetermined width in said one-dimensional scan direction and having a predetermined length in a cross-direction of said one-dimensional scan direction,
- wherein the middle of said width is arranged substantially at the center of said circular image field and said length is adjusted substantially in coincidence with a size of said shot area along said cross-direction;
- and
- (c) scanning the mask and the plate relative to said rectangular effective image area in the one-dimensional scan direction with a predetermined velocity ratio in order to successively expose different portions of said shot area with rectangular pattern image portions of the mask.
A method for scanning exposure in which a pattern region of a mask is projected onto a shot area of a photosensitive plate through a projection system, and the mask and plate are at least one-dimensionally, relatively scanned with respect to a field of said projection system, the method comprising the steps of:
- (a) providing a double telecentric projection lens having a circular image field which is smaller than said shot area and an optical axis which passes through the center of said circular image field;
- (b) limiting an effective imaging area in the circular image field to an approximately rectangular shape having a predetermined width in the one-dimensional scan direction and having a predetermined length in a crossing direction of the one dimensional scan direction,
- wherein the middle of said width is arranged substantially at the center of said circular image field;
- (c) scanning the mask and plate relative to said rectangular effective imaging area in the one-dimensional scan direction with a predetermined velocity ratio in order to expose said shot area with an image of the pattern region of the mask;
- (d) optically detecting a position of a surface portion of said plate, corresponding to said rectangular effective imaging area on the plate, along said optical axis during said scanning;
- and
- (e) correcting focusing error between said surface portion of the plate and a best imaging plane of said projection lens in response to said position detecting during said scanning.
A method for scanning exposure in which a pattern region of a mask is projected onto a shot area of a photosensitive plate through a projection system, and the mask and plate are at least one-dimensionally, relatively scanned with respect to a field of said projection system, the method comprising the steps of:
- (a) providing a reduction imaging lens having a circular image field which is smaller than said shot area and an optical axis which passes through the center of said circular image field;
- (b) limiting a shape of an effective imaging area in the circular image field to a diametrically extending rectangular region having a predetermined width in the one-dimensional scan direction and having a predetermined length in a cross-direction of the one-dimensional scan direction,
- wherein the middle of said width is arranged substantially at the center of said circular image field and said length is adjusted substantially in coincidence with a size of said shot area along said cross-direction;
- (c) scanning the mask and plate relative to said rectangular effective imaging area in the one-dimensional scan direction with a predetermined velocity ratio in order to expose said shot area with an image of the pattern region of the mask;
- (d) optically detecting a focusing deviation and a leveling deviation of a surface portion of the plate corresponding to said rectangular effective imaging area on the plate, during said scanning;
- and
- (e) adjusting focusing and leveling conditions between said surface portion of the plate and a best imaging plane of said reduction imaging lens in response to said focusing and leveling deviations, respectively, during said scanning.
Dependencies are inferred from the claim text.