Mark for position detection and mark detecting method and apparatus

• US 6,356,343 B1
• Filed: 08/04/1999
• Issued: 03/12/2002
• Est. Priority Date: 11/07/1996
• Status: Expired due to Fees

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Magome, Nobutaka, Shiraishi, Naomasa
• Primary Examiner(s): Adams, Russell
• Assistant Examiner(s): NGUYEN, HUNG
• Application Number:
  US09/366,565
• Time in Patent Office: 951 Days
• Field of Search: 355/52, 355/53, 355/77, 356/399-400, 250/548, 430/5, 430/22, 430/30, 430/311
• US Class Current: 355/77
• CPC Class Codes: G03F 9/00 Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically G03F7/22 takes precedence; preparation of photographic masks G03F1/00; within photographic printing apparatus for making copies G03B27/00
• 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

A mark for position detection formed on a substrate has a first pattern disposed near the center of the mark and having periodicity in a Y-axis direction, and second patterns respectively disposed near both sides of the first pattern in an X-axis direction and each having periodicity in the X-axis direction. The position of the first pattern is detected by aligning the detection center of a detecting optical system, that is, the minimal aberration point of the detecting optical system, with the center of the first pattern. The positions of the second patterns are detected at respective points symmetric with respect to the minimal aberration point, and the detected values for the positions of the second patterns are averaged. An apparatus for detecting the mark for position detection detects the first and second patterns by image processing when the mark is in a stationary state.

Claims

1. An exposure method comprising the steps of:

preparing an orthogonal coordinate system including first and second axes perpendicular to each other;

placing an object with a mark in said orthogonal coordinate system, said mark including a first pattern comprising a plurality of bar-like patterns spaced from each other at predetermined intervals in said first axis direction and extending with longer continuity in said second axis direction than in said first axis direction, and second patterns disposed near both sides of said first pattern in said second axis direction and comprising a plurality of bar-like patterns spaced from each other at predetermined intervals in said second axis direction and extending with longer continuity in said first axis direction than in said second axis direction;

directing a detection beam to said mark;

detecting the detection beam reflected from said mark through a detecting optical system, said first pattern of said mark being detected though a portion where aberrations of the detecting optical system are minimized;

attaining information with respect to the position of said object based on said detection beam; and

determining the position of said object with respect to said first and second axes based on said information.

2. An exposure method according to claim 1, said attaining step comprising:

detecting photoelectrically said mark; and

processing a signal detected in said detecting step to thereby attain information with respect to a position of said mark in said first and second axis directions.

3. An exposure method according to claim 2, said attaining step comprising:

detecting photoelectrically said first pattern and second patterns in parallel.

4. An exposure method according to claim 2, wherein said attaining step comprises;

achieving an image pickup process for said mark; and

attaining information with respect to the position of said mark in said first and second axis direction based on the result of said image pickup process.

5. An exposure method according to claim 4, wherein said portion where the aberrations are minimized includes an optical axis of said detecting optical device.

6. An exposure method according to claim 4, said attaining step comprising:

obtaining a position of said mark in said second axis direction by averaging data obtained from said second patterns.

7. An exposure method according to claim 4, said attaining step comprising:

attaining said information when a stage on which said object is placed is in a stationary state.

8. An exposure method according to claim 4, said attaining step comprising:

processing only a detection signal obtained from said second pattern in obtaining a position of said mark in said second axis direction.

9. An exposure method according to claim 8, said attaining step comprising:

setting up a slice level of said detection signal, with which a position of said mark is obtained in said second axis direction, higher than a predetermined value.

10. An exposure method according to claim 9, wherein said predetermined value is the level of a detection signal above which said first pattern is detected in detecting said second axis direction.

11. An exposure method according to claim 1, further comprising:

projecting a predetermined pattern onto said object through a projection optical system;

wherein said attaining step comprises detecting said mark with an objective optical system which is independent from said projection optical system.

12. An exposure method according to claim 1, wherein said first pattern is disposed near a center in said second axis direction of said mark.

13. An exposure method according to claim 1, wherein said first pattern is disposed near a center of said mark for position detection.

14. An exposure method according to claim 1, wherein said second patterns are disposed in a symmetric relation to each other with respect to a center in said second axis direction of said mark.

15. An exposure method according to claim 13, wherein said second patterns are disposed in a symmetric relation to each other with respect to a center of said mark.

16. An exposure method according to claim 1, wherein said first pattern is utilized to detect a position in said first axis direction of said object, and said second patterns are utilized to detect a position in said second axis direction of said object.

17. An exposure method according to claim 1, wherein said first pattern has periodicity only in said first axis direction, and said second patterns have periodicity only in said second axis direction.

18. An exposure method according to claim 1, wherein said object comprises a substrate.

19. A method for manufacturing a device including a step of exposing predetermined pattern onto a substrate by using the exposure method of claim 1.

20. A method for manufacturing an exposure apparatus comprising the steps of:

providing a mark detecting device which detects a position of a mark formed on an object with relation to first and second axes perpendicular to each other, said mark has a first pattern comprising a plurality of bar-like patterns spaced from each other at predetermined intervals in said first axis direction and extending with longer continuity in said second axis direction than in said first axis direction, and second patterns disposed near both sides of said first pattern in said second axis direction and comprising a plurality of bar-like patterns spaced from each other at predetermined intervals in said second axis direction and extending with longer continuity in said first axis direction than in said second axis direction, said mark detecting device including a detecting optical system, said mark detecting device detecting said first pattern through a portion where aberrations of the detecting optical are minimized; and

providing a position detecting apparatus connected electrically with said mark detecting device so that the position detecting apparatus determines, a position of said object on the basis of a detection signal detected by said mark detecting device.

21. A method for manufacturing an exposure apparatus according to claim 20, further comprising:

providing a projection optical system which projects a predetermined pattern onto said object, wherein said mark detecting device has an objective optical system which is independent from said projection optical system.

22. A method for manufacturing an exposure apparatus to claim 21, wherein said mark detecting device achieves an image pickup process for said mark.

23. A method for manufacturing an exposure apparatus according to claim 20, wherein said object comprises a substrate, and said mark detecting device includes a light source which generates light of wide band having a component of wavelengths different from those to which said substrate is sensitive.

24. A method for manufacturing an exposure apparatus according to claim 20, wherein said portion where the aberrations are minimized includes an optical axis of said detecting optical system.

25. An exposure method comprising the steps of:

preparing a mark detecting device having a detecting optical system;

disposing a central mark region of a mark formed on an object, for being detected its position with relation to first and second axes perpendicular to each other, near a portion where aberrations of said detecting optical system are minimized;

directing a detection beam to said mark;

detecting a position in said first axis direction of said mark by using said detection beam reflected from said central mark region, and detecting a position in said second axis direction of said mark by using said detection beam reflected from mark regions which are placed adjacent to both sides of said central mark region in said second axis direction.

26. An exposure method according to claim 25, wherein said central mark region is aligned with an optical axis of said detecting optical system, and said mark regions adjacent to said central mark region are positioned symmetrically with respect to said optical axis.

27. An exposure method according to claim 25, wherein said mark detecting step comprising:

detecting photoelectrically said mark to thereby receive a detection signal; and

obtaining a position of said mark with respect to said first and second axis directions by processing said detection signal.

28. An exposure method according to claim 27, wherein said detecting step comprises:

achieving an image pickup process for said mark; and

attaining information with respect to the position of said mark in said first and second axis directions based on the result of said image pickup process.

29. An exposure method according to claim 25, further comprising:

projecting a predetermined pattern onto said object through a projection optical system; and

wherein said mark detecting step comprises the step of detecting said mark through an objective optical system which is independent from said projection optical system.

30. An exposure method according to claim 25, wherein said object comprises a substrate, and said detection beam comprises light of wide band having a component of wavelengths different from those to which said substrate is sensitive.

31. An exposure method according to claim 25, wherein in said central mark region, there is provided with a first pattern comprising a plurality of bar-like patterns spaced from each other at predetermined intervals in said first axis direction and extending with longer continuity in said second axis direction than in said first axis direction;

and

in both sides of said central mark region, there are provided with second patterns comprising a plurality of bar-like patterns spaced from each other at predetermined intervals in said second axis direction and extending with longer continuity in said first axis;

direction than in said second axis direction.

32. An exposure method according to claim 25, wherein said first pattern has periodicity only in said first axis direction, and said second patterns have periodicity only in said second axis direction.

33. A method for manufacturing a device including a step of exposing a predetermined pattern onto a substrate by using the exposure method of claim 25.

34. A method for manufacturing an exposure apparatus comprising:

providing a mark detecting device which detects a position of a mark formed on an object with relation to first and second axes perpendicular to each other, said mark detecting device having a detection optical system, wherein said mark detecting device detects a position in said first axis direction of said mark while disposing a central mark region of said mark near a portion where aberrations of the detecting optical system are minimized, and detects a position in said second axis direction of said mark by observing mark regions which are placed adjacent to both sides of said central mark region in said second axis direction; and

providing a position detecting apparatus connected electrically with said mark detecting device so that the position detecting apparatus determines, a position of said object on the basis of a detection signal detected by said mark detecting device.

35. A method for manufacturing an exposure apparatus according to claim 34, further comprising:

providing a projection optical system for projecting a predetermined pattern onto said object, wherein said mark detecting device has an objective optical system which is independent from said projection optical system.

36. A method for manufacturing an exposure apparatus according to claim 34, wherein said object comprises a substrate, and said mark detecting device generates light of wide band having a component of wavelengths different from those to which said substrate is sensitive.

37. A method for manufacturing an exposure apparatus according to claim 34, wherein said mark detecting achieves an image pickup process for said mark.

38. A method for manufacturing an exposure apparatus according to claim 34, wherein said portion where the aberrations are minimized includes an optical axis of said detecting optical system.