Photocopying – Projection printing and copying cameras – Step and repeat
Reexamination Certificate
1998-07-16
2001-12-25
Adams, Russell (Department: 2851)
Photocopying
Projection printing and copying cameras
Step and repeat
C355S067000, C355S068000
Reexamination Certificate
active
06333777
ABSTRACT:
FIELD OF THE INVENTION AND RELATED ART
This invention relates to an exposure apparatus and a device manufacturing method. More particularly, the invention is concerned with an exposure apparatus and/or a device manufacturing method which assures high resolution and which is suitable for the manufacture of devices on the basis of a step-and-repeat procedure or a step-and-scan procedure.
For projection exposure apparatuses for recent semiconductor device manufacture, a performance capable of forming a higher resolution pattern has been required to meet a further enlargement of integration, such as VLSI, for example.
As an attempt to provide a projection exposure apparatus that meets this requirement, Japanese Laid-Open Patent Application, Laid-Open No. 47629/1993 or Laid-Open No. 204123/1994 proposes a projection exposure apparatus which uses an ultra-resolution imaging technique called an oblique incidence illumination or phase shift mask. In such systems, the diameter of an aperture of an aperture stop provided in an illumination system is reduced to make a &sgr; value (the ratio of the numerical aperture of a projection optical system and the numerical aperture of an illumination optical system) smaller. Alternatively, the surface to be illuminated is illuminated with a secondary light source of a specific shape such as a ring-like shape or quadrant-pole shape.
On the other hand, in order that a projection exposure apparatus provides a sufficient resolving power, the angle light quantity distribution of illumination light flux for illuminating a certain point on a mask or a wafer (i.e., the angular distribution of illumination light) should be set to a best state or a state near it. If illumination light set to such a state cannot be supplied to the projection optical system, there occurs a lateral deviation of an image if the wafer is defocused.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an exposure apparatus and/or a device manufacturing method by which a pattern of a mark or reticle (hereinafter, “mask”) can be projected onto a substrate such as a wafer, for example, with high resolution.
In accordance with an aspect of the present invention, there is provided an exposure apparatus for illuminating a pattern with exposure light and for projecting the pattern onto a substrate through a projection optical system, said apparatus comprising: an illuminometer being movable along a pattern projection plane with its light receiving portion being registered with the pattern projection plane and movable along an optical axis direction of the projection optical system, for measurement of an illuminance distribution on the pattern projection plane; and masking means having a variable size aperture, for regulating an exposure range on the pattern projection plane; wherein said masking means serves to regulate the exposure range so that a light intensity distribution at a pupil plane of the optical system is defined at a plane displaced from the pattern projection plane in the optical axis direction, and wherein said illuminometer is moved along the displaced plane while the light receiving portion of said illuminometer is registered with the displaced plane, to perform the measurement of the light intensity distribution.
In accordance with a further aspect of the present invention, there is provided an exposure apparatus for illuminating a pattern with exposure light and for projecting the pattern onto a substrate through a projection optical system, said apparatus comprising: an illuminometer being movable along a pattern projection plane with its light receiving portion being registered with the pattern projection plane and movable along an optical axis direction of the projection optical system, for measurement of an illuminance distribution on the pattern projection plane; and masking means having a variable size aperture, for regulating an exposure range on the pattern projection plane; wherein said masking means serves to regulate the exposure range so that a shift of a chief ray of the exposure light is defined on a plane displaced from the pattern projection plane in the optical axis direction, and wherein said illuminometer is moved along the displaced plane while the light receiving portion of said illuminometer is registered with the displaced plane, to perform the measurement of the shift of the chief ray.
In accordance with a yet further aspect of the present invention, there is provided an exposure apparatus for illuminating a pattern with exposure light and for projecting the pattern onto a substrate through a projection optical system which is telecentric on its light exit side, said apparatus comprising: a detector for detecting an amount of tilt of a chief ray of the exposure light with respect to an optical axis of the projection optical system; adjusting means for adjusting a tilt angle of the chief ray of the exposure light in accordance with the detection by said detector, to bring the chief ray of the exposure light parallel to the optical axis of the projection optical system; and correcting means for correcting non-uniformness of illuminance on a pattern projection plane to be produced by the adjustment through said adjusting means.
In accordance with a still further aspect of the present invention, there is provided an exposure apparatus for projecting a pattern onto a substrate with exposure light through a projection optical system, said apparatus comprising: a detector for detecting asymmetry of a light intensity distribution upon a pupil plane of the projection optical system; adjusting means for adjusting the exposure light in accordance with the detection by said detector, to bring the intensity distribution on the pupil plane into symmetry with respect to an exposure optical axis; and correcting means for correcting non-uniformness of illuminance on a pattern projection plane to be produced by the adjustment through said adjusting means.
In accordance with a yet further aspect of the present invention, there is provided a projection exposure apparatus for illuminating a pattern with illumination light from an illumination system and for projecting the pattern onto a substrate through a projection optical system, said apparatus comprising: an illuminometer disposed at a predetermined distance away from a pattern forming surface or a plane optically conjugate with the pattern forming surface, with respect to an optical axis direction; wherein said illuminometer serves to detect an angular distribution of the illumination light; and wherein a component of the illumination system is rotationally moved or moved along a plane orthogonal to an optical axis to adjust the angular distribution of the illumination light.
In accordance with another aspect of the present invention, there is provided a projection exposure apparatus for illuminating a pattern with illumination light from an illumination system and for projecting the pattern onto a substrate through a projection optical system, said apparatus comprising: masking means included In the illumination system and disposed on a plans optically conjugate with a pattern forming surface, for regulating the size of a surface to be illuminated; an illuminometer disposed at a predetermined distance away from said masking means or a plane optically conjugate with said masking means, with respect to an optical axis direction, for detecting an angular distribution of the illumination light; wherein a component of the illumination system is rotationally moved or moved along a plane orthogonal to an optical axis to adjust the angular distribution of the illumination light.
The illumination system may include secondary light source forming means sucb as a fly's eye lens, for example.
The component of the illumination system may comprise a lens system disposed at a light entrance side of said secondary light source forming means.
The component of the illumination system may comprise a parallel flat plate disposed at a light entrance side of said secondary light source forming means
Adams Russell
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Kim Peter B.
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