Exposure apparatus and exposure method for minimizing defocusing of the transferred pattern

• US 5,640,227 A
• Filed: 12/06/1994
• Issued: 06/17/1997
• Est. Priority Date: 12/06/1993
• Status: Expired due to Term

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Saiki, Kazuaki, Kato, Masaki, Kato, Kinya, Seki, Masami
• Primary Examiner(s): Pendegrass, Joan H.
• Application Number:
  US08/349,869
• Time in Patent Office: 924 Days
• Field of Search: 355/53, 355/67, 355/55, 250/548, 356/356, 356/358, 356/400, 356/401
• US Class Current: 355/53
• CPC Class Codes: G03F 7/70358 Scanning exposure, i.e. relative movement of patterned beam and workpiece during imaging
• CPC Class Codes: G03F 9/7026 Focusing

Abstract

An exposure apparatus and an exposure method which minimize defocusing of the transferred pattern even with a large-sized mask. When the exposure apparatus is used which transfers the pattern formed on a first substrate through a substantially real-size projection optical system onto a second substrate, the positions of the mask and the substrate are detected, and based on the information on the positions the distance between the mask and the substrate is controlled to be substantially constant. According to the present invention, defocusing of the transferred pattern may be substantially avoided by detecting positions of the mask and the plate by making use of, e.g., an obliquely incident light focus detection optical system, and controlling the distance therebetween to be held constant or at a predetermined distance.

Claims

1. An exposure apparatus for performing projection exposure of the pattern formed on a first substrate supported on a first stage onto a second substrate supported on a second stage, comprising:

a real-size and both-side telecentric projection optical system said projection exposure is performed therethrough;

position detection means for detecting the positions of said first and second substrates in the direction of the optical axis of said projection optical system; and

positioning control means for keeping constant the distance between said first and second substrates by positioning at least one of said first and second stages based on the positional information obtained through detection with said position detection means,

wherein said position detection means comprises light incidence means for oblique incidence of beams of light on said first and second substrates, and photoreceptive means for receiving the reflected light from said first and second substrates; and

said positioning control means positions at least one of said first and second stages based on the positions where the reflected light from said first and second substrates are received.

2. An exposure apparatus according to claim 1, wherein said light incidence means comprises first light incidence means for oblique incidence of beams of light on said first substrate, and second light incidence means for oblique incidence of beams of light on said second substrate.

3. An exposure apparatus according to claim 2, further comprising light quantity control means for controlling the quantity of the light emitted from said first and second light incidence means, based on the quantity of the light reflected from said first and second substrates.

4. An exposure apparatus according to claim 1, wherein said photoreceptive means comprises first photoreceptive means for receiving the reflected light from said first substrate, and second photoreceptive means for receiving the reflected light from said second substrate;

and further comprising sensitivity control means for controlling the sensitivity of said first and second photoreceptive means.

5. An exposure apparatus according to claim 1, wherein said positioning control means controls the position of at least one of said first and second stages, based on the distance between the point for receiving the reflected light from said first substrate and the point for receiving the reflected light from said second substrate.

6. An exposure apparatus according to claim 1, wherein said positioning control means controls the positions of said first and second substrates, based on the positions the reflected light from said first and second substrates is received thereat.

7. An exposure apparatus for performing projection exposure os the pattern formed on a first substrate supported on a first stage onto a second substrate supported on a second stage while scanning said first and second substrates, comprising:

a real-size and both-side telecentric projection optical system said projection exposure is performed therethrough, said scanning being performed in the direction perpendicular to the optical axis of said projection optical system;

position detection means for detecting the position of said first and second substrates in the direction of the optical axis of said projection optical system; and

positioning control means for keeping constant the distance between said first and second stages based on the positional information obtained through detection with said position detection means,

wherein said position detection means detects the positions of said first and second substrates at a plurality of the scanning points during prescanning in a non-exposure condition; and

said positioning control means controls the position of at least one of said first and second substrates, based on the positional information from said position detection means at said plurality of scanning points to keep constant the distance between said first and second substrates over the range of scanning.

8. An exposure apparatus according to claim 7, wherein said position detection means detects the positions of said first and second substrates over substantially the entire surfaces thereof.

9. An exposure apparatus for performing scaled-up projection exposure of the pattern formed on a first substrate supported on a first stage onto a second substrate supported on a second stage, comprising:

a both-side telecentric projection optical system said projection exposure is performed therethrough;

position detection means for independently detecting each of the positions of said first and second substrates in the direction of the optical axis of said projection optical system; and

positioning control means for controlling the position of at least one of said first and second stages, based on the positional information obtained through detection with said position detection means.

10. An exposure apparatus for performing scaled-down projection exposure of the pattern formed on a first substrate supported on a first stage onto a second substrate supported on a second stage, comprising:

a both-side telecentric projection optical system said projection exposure is performed therethrough;

position detection means for independently detecting each of the positions of said first and second substrates in the direction of the optical axis of said projection optical system; and

positioning control means for controlling the position of at least one of said first and second stages, based on the positional information obtained through detection with said position detection means.

11. An exposure method for performing projection exposure of the pattern formed on a first substrate supported on a first stage onto a second substrate supported on a second stage through an real-size, both-side telecentric projection optical system, while scanning said first and second substrates relative to said projection optical system in a direction perpendicular to the direction of the optical axis of said projection optical system, comprising:

detecting the positions of said first and second substrates at a plurality of scanning points in the direction of the optical axis of said projection optical system with a position detection means, in a non-exposure condition; and

controlling the position of at least one of said first and second stages in the direction of the optical axis of said projection optical system, based on the positional information obtained through detection with said position detection means, thereby performing projection exposure of the pattern formed on said first substrate onto a second substrate while keeping constant the distance between said first and second substrates.

12. An exposure apparatus for performing projection exposure of the pattern formed on a first substrate supported on a first stage onto a second substrate supported on a second stage, comprising:

a both-side telecentric projection optical system said projection exposure is performed therethrough;

an incidence optical system for oblique incidence of beams of light on the surface of a light incidence substrate which is one of said first and second substrates;

a relay optical system for condensing beams of the light reflected from the surface of said light incidence substrate and for incidence of the beams on the surface of a light-leaving substrate which is the rest of said first and second substrates;

a reimaging optical system for condensing beams of the light reflected from the surface of said light-leaving substrate to reform the image;

an image position detection means for detecting the position of the reformed image; and

a position adjusting means for adjusting the position of at least one of said first and second stages in the direction of the optical axis of said projection optical system so that the position of the image detected by said image position detection mean is constant.

13. An exposure apparatus according to claim 12, wherein the following relationship is satisfied:

space="preserve" listing-type="equation">0.9 ·

(sinθ

'"'"'/sinθ

) β

.sup.2 ≦

β

'"'"'≦

1.1 ·

(sinθ

'"'"'/sinθ

) β

.sup.2,

here, θ

is the angle between the optical axis of beams of light incident on said light incidence substrate and the normal to the surface of said light incidence substrate, θ

'"'"' is the angle between the optical axis of beams of light incident on said light-leaving substrate and the normal to the surface of said light-leaving substrate, β

is the projection magnification of said projection optical system from said light incidence substrate to said light-leaving substrate, β

'"'"' is the projection magnification of said relay optical system from said light incidence substrate to said light-leaving substrate.

14. An exposure apparatus according to claim 12, wherein said relay optical system is both-side telecentric.

15. An exposure apparatus for performing projection exposure of the pattern formed on a first substrate supported on a first stage onto a second substrate supported on a second stage, comprising:

a real-size and both-side telecentric projection optical system said projection exposure is performed therethrough;

position detection means for detecting the positions of said first and second substrates in the direction of the optical axis of said projection optical system; and

positioning control means for keeping constant the distance between said first and second substrates by positioning at least one of said first and second stages based on the positional information obtained through detection with said position detection means, wherein said position detection means detects each of the positions of said first and second substrates independently.

16. An exposure apparatus according to claim 15, wherein said position detection means comprises light incidence means for oblique incidence of beams of light on said first and second substrates, and photoreceptive means for receiving the reflected light from said first and second substrates;

and

said positioning control means positions at least one of said first and second stages based on the positions where the reflected light from said first and second substrates are received.

17. An exposure apparatus according to claim 16, wherein said light incidence means comprises first light incidence means for oblique incidence of beams of light on said first substrate, and second light incidence means for oblique incidence of beams of light on said second substrate.

18. An exposure apparatus according to claim 17, further comprising light quantity control means for controlling the quantity of the light emitted from said first and second light incidence means, based on the quantity of the light reflected from said first and second substrates.

19. An exposure apparatus according to claim 16, wherein said photoreceptive means comprises first photoreceptive means for receiving the reflected light from said first substrate, and second photoreceptive means for receiving the reflected light from said second substrate;

and further comprising sensitivity control means for controlling the sensitivity of said first and second photoreceptive means.

20. An exposure apparatus according to claim 16, wherein said positioning control means controls the position of at least one of said first and second stages, based on the distance between the point for receiving the reflected light from said first substrate and the point for receiving the reflected light from said second substrate.

21. An exposure apparatus according to claim 16, wherein said positioning control means controls the positions of said first and second substrates, based on the positions where the reflected light from said first and second substrates is received.

22. An exposure apparatus according to claim 15 for performing projection exposure while scanning said first and second substrates in the direction perpendicular to the optical axis of said projection optical system,

wherein said position detection means detects the positions of said first and second substrates at a plurality of the scanning points during prescanning in a non-exposure condition;

and

said positioning control means controls the position of at least one of said first and second substrates, based on the positional information from said position detection means at said plurality of scanning points to keep constant the distance between said first and second substrates over the range of scanning.

23. An exposure apparatus according to claim 22, wherein said position detection means detects the positions of said first and second substrates over substantially the entire surfaces thereof.

24. An exposure apparatus for performing projection exposure of the pattern formed on a first substrate supported on a first stage onto a second substrate supported on a second stage, comprising:

a both-side telecentric and real-size projection optical system;

an incidence optical system for oblique incidence of beams on the surface of one of said first and second substrates, said incidence optical system having an optical axis which is slanting with respect to the optical axis of said projection optical system;

a relay optical system for oblique incidence of beams on the surface of the rest of said first and second substrates, said relay optical system being arranged at a position where the beams reflected from the surface of said one of the substrates are received;

a reimaging optical system, arranged at a position where the beams reflected from the surface of said rest of the substrates are received, for condensing said beams;

a detector arranged at a position where a light spot formed by said reimaging optical system is formed; and

a unit, connected with said detector and with at least one of said first and second stages, for adjusting the position of at least one of said first and second stages in the direction of the optical axis of said projection optical system so that the position of the light spot formed on said detector is constant.

25. An exposure apparatus for performing projection exposure of the pattern formed on a first substrate supported on a first stage onto a second substrate supported on a second stage, comprising:

a both-side telecentric and real-size projection optical system;

an incidence optical system for oblique incidence of beams on the surface of said first and second substrates, said incidence optical system having an optical axis which is slanting with respect to the optical axis of said projection optical system;

a photoreceptive optical system, arranged at a position where the beams reflected from the surface of said first and second substrates are received, for guiding said reflected beams onto said detector; and

a unit, connected with said detector, for positioning at least one of said first and second stages based an the position of said beams guided onto said detector so that the distance between said first and second substrates is constant.

26. An exposure apparatus according to claim 25, wherein said incidence optical system comprises:

a first incidence optical system, having an optical axis which is slanting with respect to the optical axis of said projection optical system, for oblique incidence of beams on the surface of said first substrate; and

a second incidence optical system, having an optical axis which is slanting with respect to the optical axis of said projection optical system, for oblique incidence of beams on the surface of said second substrate;

and wherein said photoreceptive optical system comprises;

a first photoreceptive optical system arranged at a position where the beams reflected from said first substrate are received; and

a second photoreceptive optical system arranged at a position where the beams reflected from said second substrate are received.

27. An exposure apparatus according to claim 26, wherein said photoreceptive optical system is arranged so that beams which pass through said first photoreceptive optical system after reflected from said first substrate and beams which pass through said second photoreceptive optical system after reflected from said second substrate may be guided onto the same detector.

28. An exposure apparatus according to claim 25, wherein said incidence optical system comprises:

a first incidence optical system for oblique incidence of beams on the surface of one of said first and second substrates, said first incidence optical system having an optical axis which is slanting with respect to the optical axis of said projection optical system; and

a relay optical system, arranged at a position where the beams reflected from the surface of said one of the substrates are received, for obliquely guiding said reflected beams onto the surface of the rest of said first and second substrates;

and wherein said photoreceptive optical system, arranged at a position where the beams reflected from the surface of said rest of the substrates are received, for guiding said beams reflected from the surface of said rest of the substrates onto said detector.

29. An exposure apparatus according to claim 28, wherein said unit positions at least one of said first and second stages so that the position of the beams guided onto said detector is constant.