Exposure apparatus and method

• US 5,657,130 A
• Filed: 03/22/1995
• Issued: 08/12/1997
• Est. Priority Date: 03/28/1994
• Status: Expired due to Term

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Saiki, Kazuaki, Shirasu, Hiroshi, Mori, Susumu, Miyazaki, Seiji
• Primary Examiner(s): HANTIS, KAREN
• Application Number:
  US08/408,714
• Time in Patent Office: 874 Days
• Field of Search: 356/399-401, 355/43, 355/53, 250/559.3, 250/548
• US Class Current: 356/401
• CPC Class Codes: G03F 7/70216 Mask projection systems
• CPC Class Codes: G03F 7/70275 Multiple projection paths, e.g. array of projection systems, microlens projection systems or tandem projection systems
• CPC Class Codes: G03F 7/70358 Scanning exposure, i.e. relative movement of patterned beam and workpiece during imaging
• CPC Class Codes: G03F 7/70791 Large workpieces, e.g. glass substrates for flat panel displays or solar panels
• CPC Class Codes: G03F 9/70 for microlithography measuring printed patterns for monitoring overlay G03F7/70633 or focus G03F7/70641; projection system adjustment G03F7/70258; position control G03F7/70775

Abstract

In an exposure apparatus and method, a mask and a substrate are scanned in synchronism with each other so that the pattern of the mask may be transferred onto the substrate through a projection optical system. First beams of light are irradiated to least two locations on the mask spaced apart in a direction intersecting the scanning direction of the mask. The reflected light thereof is received, and the positions of the points on the mask to which the beam of light has been irradiated are detected in the direction of the optical axis of the projection optical system. In addition, second beams of light are irradiated to at least two locations on the substrate spaced apart in the scanning direction, and the reflected light thereof is received. The positions of the points on the substrate to which the second beam of light has been irradiated are also detected in the direction of the optical axis of the projection optical system are detected. The posture of at least one of the mask and the substrate is adjusted on the basis of the positions detected with the first and second beams.

Claims

1. A scanning type exposure apparatus, comprising:

a scanning system for scanning a mask and a substrate in synchronism with each other so that a pattern of said mask can be transferred onto said substrate at one-to-one magnification through a projection optical system;

a first detecting system for irradiating first beams of light to at least two first points on said mask spaced apart along a direction orthogonal to a scanning direction of said mask, receiving reflected light from said first points, and detecting positions of said first points along an optical axis of said projection optical system;

a second detecting system for irradiating second beams of light to at least two second points on said substrate spaced apart along a direction orthogonal to a scanning direction of said substrate, receiving reflected light from said second points, and detecting positions of said second points along the optical axis of said projection optical system; and

an adjusting system for adjusting posture of at least one of said mask and said substrate based on the positions detected by said first detecting system and said second detecting system.

2. A scanning type exposure apparatus according to claim 1, wherein said first beams of light are irradiated to said first points within a pattern forming area of said mask before transfer of a portion of the mask pattern in said pattern forming area, and said second beams of light are irradiated to said second points within a pattern transfer area of said substrate before transfer of said pattern portion.

3. A scanning type exposure apparatus according to claim 1, wherein said projection optical system has a first optical system and a second optical system arranged at a predetermined interval, and said first detecting system and said second detecting system effect the detection of said positions at predetermined intervals of scanning movement of said substrate and said mask.

4. A scanning type exposure apparatus according to claim 1, wherein said first points and said second points are equal in number, and said adjusting system adjusts said posture to position said first points and said second points in conjugate relation with respect to said projection optical system.

5. A scanning type exposure apparatus according to claim 1, wherein said posture includes at least one of a position along the optical axis of said projection optical system and an inclination with respect to the optical axis of said projection optical system.

6. A scanning type exposure apparatus comprising:

a scanning system for scanning a mask and a substrate in synchronism with each other so that a pattern of said mask can be transferred onto said substrate through a projection optical system;

a first detecting system for irradiating first beams of light to at least two first points on said mask spaced apart in a direction intersecting a scanning direction of said mask, receiving reflected light from said first points, and detecting positions of said first points along an optical axis of said projection optical system;

a second detecting system for irradiating second beams of light to at least two second points on said substrate spaced apart in a direction intersecting a scanning direction of said substrate, receiving reflected light from said second points, and detecting positions of said second points along the optical axis of said projection optical system; and

an adjusting system for adjusting posture of at least one of said mask and said substrate based on the positions detected by said first detecting system and said second detecting system.

7. A scanning type exposure apparatus according to claim 6, wherein said first beams of light are irradiated to said first points within a pattern forming area of said mask before transfer of a portion of said mask pattern in said pattern forming area, and said second beams of light are irradiated to said second points within a pattern transfer area of said substrate before transfer of said pattern portion.

8. A scanning type exposure apparatus according to claim 6, wherein said first points and said second points are equal in number, and said adjusting system adjusts said posture to position said first points and said second points in conjugate relation with respect to said projection optical system.

9. A scanning type exposure apparatus according to claim 6, wherein said posture includes at least one of a position along the optical axis of said projection optical system and an inclination with respect to the optical axis of said projection optical system.

10. An exposure method including the steps of:

(a) scanning a mask and a substrate in synchronism with each other so that a pattern of said mask can be transferred onto said substrate through a projection optical system;

(b) irradiating first beams of light to at least two points on said mask spaced apart along a direction intersecting a scanning direction of said mask, receiving reflected light from said first points, and detecting positions of said first points along an optical axis of said projection optical system;

(c) irradiating second beams of light to at least two points on said substrate spaced apart in a direction intersecting a scanning direction of said substrate, receiving reflected light from said second points, and detecting positions of said second points along the optical axis of said projection optical system; and

(d) adjusting posture of at least one of said mask and said substrate based on the detected positions of said first points and said second points.

11. An exposure method according to claim 10, wherein said steps (b) and (c) are performed repeatedly, for different sets of first points and different sets of second points, respectively, with the scanning of said mask and said substrate, and the detected positions for each set of points are stored.

12. An exposure method according to claim 10, wherein said posture includes at least one of a position along the optical axis of said projection optical system and an inclination with respect to the optical axis of said projection optical system.

13. A scanning type exposure apparatus for transferring a pattern of a mask onto a substrate through a projection optical system by scanning said mask and said substrate, comprising:

a light source to irradiate exposure light;

a first detecting system which has at least one first measurement point spaced apart, along a scanning direction of said mask, from a first predetermined area to be irradiated with the exposure light from said light source, said first detecting system detecting a position of said mask along an optical axis of said projection optical system at each said first measurement point;

a second detecting system which has at least one second measurement point spaced apart, along a scanning direction of said substrate, from a second predetermined area to be irradiated with the exposure light through said mask and said projection optical system, said second detecting system detecting a position of said substrate along the optical axis of said projection optical system at each said second measurement point; and

an adjusting system to adjust posture of at least one of said mask and said substrate based on detecting results of said first and second detecting systems.

14. A scanning type exposure apparatus according to claim 13, wherein said posture includes at least one of a position along the optical axis of said projection optical system and an inclination with respect to the optical axis of said projection optical system.

15. A scanning type exposure apparatus according to claim 13, wherein said first and second measurement points are in conjugate relation to each other with respect to said projection optical system.

16. A scanning type exposure apparatus according to claim 13, wherein said first detecting system has a plurality of first measurement points displaced from each other along a direction orthogonal to said scanning direction of said mask, and said second detecting system has a plurality of second measurement points displaced from each other along a direction orthogonal to said scanning direction of said substrate.

17. A scanning type exposure apparatus according to claim 13, wherein said adjusting system adjusts the posture of at least one of said mask and said substrate, based on the detected positions of said mask and said substrate, so as to maintain a predetermined interval between said mask and said substrate.

18. A scanning type exposure apparatus according to claim 13, wherein said first measurement point is disposed in advance of said first predetermined area along said scanning direction of said mask, and said second measurement point is disposed in advance of said second predetermined area along said scanning direction of said substrate.

19. A scanning type exposure apparatus according to claim 13, wherein said first predetermined area includes two areas to be irradiated with the exposure light which are disposed at a predetermined interval along said scanning direction of said mask, and are displaced from each other along a direction orthogonal to said scanning direction of said mask.

20. A scanning type exposure apparatus according to claim 19, wherein said first measurement point and one of said two areas closer to said first measurement point are disposed at an interval which is an integer multiple of said predetermined interval.

21. A scanning type exposure apparatus according to claim 13, wherein said second predetermined area includes two areas to be irradiated with the exposure light which are disposed at a predetermined interval along said scanning direction of said substrate, and are displaced from each other along a direction orthogonal to said scanning direction of said substrate.

22. A scanning type exposure apparatus according to claim 21, wherein said second measurement point and one of said two areas closer to said second measurement point are disposed at an interval which is an integer multiple of said predetermined interval.

23. A scanning type exposure apparatus according to claim 13, further comprising:

a scanning stage to scan said mask and said substrate as a unit with respect to said exposure light.

24. A scanning type exposure apparatus according to claim 13, further comprising:

a memory to store information on relative displacement between said mask and said substrate upon scanning, and

wherein said adjusting system reads out information on relative displacement from said memory, and, based on the information read out, adjusts the posture of at least one of said mask and said substrate while said mask and said substrate are being scanned and the pattern of said mask is being transferred onto said substrate.

25. A scanning exposure method for transferring a pattern of a mask onto a substrate through a projection optical system by scanning said mask and said substrate with respect to exposure light from a light source, said method comprising:

irradiating first light for position detection to at least one first measurement point spaced apart, along a scanning direction of said mask, from a first predetermined area to be irradiated with the exposure light from said light source, and detecting a position of said mask along an optical axis of said projection optical system at each said first measurement point;

irradiating second light for position detection to at least one second measurement point spaced apart, along a scanning direction of said substrate, from a second predetermined area to be irradiated with the exposure light through said mask and said projection optical system, and detecting a position of said substrate along the optical axis of said projection optical system at each said second measurement point; and

adjusting posture of at least one of said mask and said substrate based on the detected positions of said mask and said substrate.

26. A scanning exposure method according to claim 25, wherein said posture includes at least one of a position along the optical axis of said projection optical system and an inclination with respect to the optical axis of said projection optical system.

27. A scanning exposure method according to claim 25, wherein said first and second measurement points are in conjugate relation to each other with respect to said projection optical system.

28. A scanning exposure method according to claim 25, wherein said first light for position detection is irradiated to a plurality of first measurement points displaced from each other along a direction orthogonal to said scanning direction of said mask, and said second light for position detection is irradiated to a plurality of second measurement points displaced from each other along a direction orthogonal to said scanning direction of said substrate.

29. A scanning exposure method according to claim 25, wherein the posture of at least one of said mask and said substrate is adjusted, based on the detected positions of said mask and said substrate, so as to maintain a predetermined interval between said mask and said substrate.

30. A scanning exposure method according to claim 25, wherein the posture of at least one of said mask and said substrate is adjusted, based on the detected positions of said mask and said substrate, so as to maintain a conjugate relation between said mask and said substrate with respect to said projection optical system.

31. A scanning exposure method according to claim 25, wherein said first measurement point is disposed in advance of said first predetermined area in said scanning direction of said mask, and said second measurement point is disposed in advance of said second predetermined area in said scanning direction of said substrate.

32. A scanning exposure method according to claim 25, wherein said first predetermined area includes two areas to be irradiated with the exposure light which are disposed at a predetermined interval in said scanning direction of said mask, and which are displaced from each other in a direction orthogonal to said scanning direction of said mask.

33. A scanning exposure method according to claim 32, wherein said first measurement point and one of said two areas closer to said first measurement point are disposed at an interval which is an integer multiple of said predetermined interval.

34. A scanning exposure method according to claim 25, wherein said second predetermined area includes two areas to be irradiated with the exposure light which are disposed at a predetermined interval along said scanning direction of said substrate, and are displaced from each other along a direction orthogonal to said scanning direction of said substrate.

35. A scanning exposure method according to claim 34, wherein said second measurement point and one of said two areas closer to said first measurement point are disposed at an interval which is an integer multiple of said predetermined interval.