Scanning exposure apparatus and method

• US 5,777,722 A
• Filed: 05/28/1996
• Issued: 07/07/1998
• Est. Priority Date: 04/28/1994
• Status: Expired due to Term

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Saiki, Kazuaki, Hamada, Tomohide, Nara, Kei, Miyazaki, Seiji, Goto, Hideji, Yokota, Muneyasu, Narabe, Tsuyoshi
• Primary Examiner(s): Moses, R. L.
• Assistant Examiner(s): Virmani, Shival
• Application Number:
  US08/654,382
• Time in Patent Office: 770 Days
• Field of Search: 355/53, 355/55, 355/77, 250/548, 356/363, 356/375, 356/400, 356/401
• US Class Current: 355/53
• 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 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 scanning exposure apparatus is arranged to illuminate a mask, to project an image of the mask through a projection optical system onto a photosensitive substrate, and to move the mask and the photosensitive substrate relative to the projection optical system, thereby effecting exposure of an entire surface of the mask on the photosensitive substrate, and the exposure apparatus comprises a position detector which detects a relative positional relation between the mask and the photosensitive substrate; a memory which stores positional information obtained by the position detector; a position correcting device which corrects the relative positional relation between the mask and the photosensitive substrate, based on the positional information read out from the memory device; and a controller which makes the position detector detect the relative positional relation between the mask and the photosensitive substrate while the mask and the photosensitive substrate are carried past a projection region of the projection optical system to an exposure start position, and makes the position correcting device correct the relative positional relation between the mask and the photosensitive substrate, based on the positional information read out from the memory, while the mask and the photosensitive substrate are stopped at the exposure start position and/or during the exposure.

Claims

1. A scanning exposure apparatus, which is arranged to illuminate a mask, to project an image of said mask through a projection optical system onto a photosensitive substrate, and to move said mask and said photosensitive substrate relative to said projection optical system, thereby effecting exposure of an entire surface of said mask on said photosensitive substrate, and which comprises:

a holding member which holds said mask and said photosensitive substrate integrally;

a position detector which detects a relative positional relation between said mask and said photosensitive substrate while said mask and said photosensitive substrate are carried by driving said holding member past a projection region of said projection optical system to an exposure start position;

a position correcting device which corrects the relative positional relation between said mask and said photosensitive substrate; and

a controller which is connected to said position correcting device and controls said position correcting device to correct the relative positional relation between said mask and said photosensitive substrate, based on positional information obtained by said position detector, while said mask and said photosensitive substrate are stopped at said exposure start position and/or during said exposure.

2. A scanning exposure apparatus according to claim 1, wherein said positional information comprises first positional information related to a direction perpendicular to an optical axis of said projection optical system and second positional information related to a direction of the optical axis of said projection optical system.

3. A scanning exposure apparatus according to claim 2, wherein said first positional information is a relative position between said mask and said photosensitive substrate and wherein said second positional information is a relative position in said direction of the optical axis between said mask and said photosensitive substrate and an amount of relative inclination between said mask and said photosensitive substrate.

4. A scanning exposure apparatus according to claim 3, wherein said controller controls said position correcting device, based on the relative position between said mask and said photosensitive substrate while said mask and said photosensitive substrate are stopped at said exposure start position, thereby correcting the positional relation related to the direction perpendicular to the optical axis of said projection optical system out of the positional relation between said mask and said photosensitive substrate and wherein during said exposure, said controller controls said position correcting device, based on the relative position related to said direction of the optical axis between said mask and said photosensitive substrate and/or the amount of relative inclination between said mask and said photosensitive substrate, thereby correcting the positional relation related to the direction of the optical axis of said projection optical system out of the positional relation between said mask and said photosensitive substrate.

5. A scanning exposure apparatus according to claim 4, further comprising a memory that retains a data map obtained based on said positional information at arbitrary positions in a scan direction, detected by said position detector.

6. A scanning exposure apparatus according to claim 1, wherein said position correcting device corrects, based on said mask, an error related to the positional relation between said photosensitive substrate and said mask with respect to the direction of an optical axis of said projection optical system.

7. A scanning exposure apparatus according to claim 5, wherein said position correcting device produces a correction map representing correction values at said arbitrary positions based on said positional information read out from said data map, and successively corrects the positional relation between said mask and said photosensitive substrate in accordance with said correction map during said exposure.

8. A scanning exposure apparatus according to claim 5, wherein said position correcting device produces a correction map representing correction values at said arbitrary positions based on said positional information read out from said data map, and successively corrects the positional relation between said mask and said photosensitive substrate in accordance with said correction map and positional information detected in real time by said position detector, during said exposure.

15. A scanning exposure apparatus according to claim 1, wherein said position detector detects said positional relation between said mask and said photosensitive substrate with respect to a direction perpendicular to an optical axis of said projection optical system with said mask and said photosensitive substrate stopped when detecting said positional relation.

16. A scanning exposure apparatus according to claim 1, wherein said position detector detects said positional relation between said mask and said photosensitive substrate with respect to the direction of an optical axis of said projection optical system, and

wherein said position correcting device drives said photosensitive substrate in a first rotational direction related to a scan direction, and a second rotational direction related to a direction perpendicular to said scan direction.

26. A scanning exposure apparatus according to claim 1, further comprising a mask holder capable of moving while holding said mask,

wherein said position correcting device is connected to said mask holder.

27. A scanning exposure apparatus according to claim 1, wherein said position detector optically detects the relative positional relation between said mask and said photosensitive substrate.

9. A scanning exposure apparatus, which is arranged to illuminate a plurality of regions on a mask, to project respective images of said plurality of regions through a plurality of projection optical systems onto a photosensitive substrate, and to move said mask and said photosensitive substrate relative to said plurality of projection optical systems, thereby effecting exposure of an entire surface of said mask on said photosensitive substrate, and which comprises:

a measuring device which measures a relative separation between said mask and said photosensitive substrate at each of arbitrary positions on said mask and said photosensitive substrate while said mask and said photosensitive substrate are synchronously carried in the same direction to an exposure start position;

a position correcting device which drives said mask and/or said photosensitive substrate to correct a relative positional relation between said mask and said photosensitive substrate; and

a controller which is connected to said position correcting device and controls said position correcting device during said exposure, based on measurement results of said measuring device, so that the relative separations between said mask and said photosensitive substrate, related to said plurality of regions from which an image of said mask is projected, satisfy a predetermined relation.

10. A scanning exposure apparatus according to claim 9, wherein each of said plurality of projection optical systems has an error related to a respective one of their focal lengths and wherein said controller performs said control, based on said errors related to said focal lengths.

11. A scanning exposure apparatus according to claim 10, wherein said position correcting device has a drive direction which is at least one of a direction perpendicular to a surface of said mask and/or a surface of said photosensitive substrate, a first rotational direction related to a scan direction, and a second rotational direction related to a direction perpendicular to said scan direction.

17. A scanning exposure apparatus according to claim 9, wherein said controller sends, in advance of a control position where said control is to be performed, control data to said position correcting device.

18. A scanning exposure apparatus according to claim 9, further comprising:

a holding member which holds said mask and said photosensitive substrate integrally,

wherein a scan is performed by moving said holding member, whereby said mask and said photosensitive substrate are moved synchronously.

28. A scanning exposure apparatus according to claim 9, further comprising:

a mask holder capable of moving while holding said mask; and

a substrate holder capable of moving while holding said photosensitive substrate,

wherein said position correcting device is connected to at least one of said mask holder and said substrate holder.

29. A scanning exposure apparatus according to claim 9, wherein said measuring device optically detects the relative separation between said mask and said photosensitive substrate.

12. A scanning exposure apparatus, which is arranged to successively transfer patterns of a mask onto a photosensitive substrate through a projection optical system while synchronously moving the mask and the photosensitive substrate in a predetermined scan direction, and which comprises:

a first position detector which detects a relative positional relation between said mask and said photosensitive substrate in two-dimensional directions perpendicular to the optical axis of the projection optical system;

a second position detector which detects a relative positional relation between said mask and said photosensitive substrate in the direction of said optical axis;

a first adjuster which adjusts the relative positional relation between said mask and said photosensitive substrate in the two-dimensional directions perpendicular to the optical axis;

a second adjuster which adjusts the relative positional relation between said mask and said photosensitive substrate with respect to the direction of the optical axis;

a first controller which is connected to said first position detector and said second position detector and controls said second adjuster to adjust the relative positional relation between said mask and said photosensitive substrate with respect to the direction of the optical axis at a predetermined alignment point while monitoring an output of said second position detector while said mask and said photosensitive substrate are synchronously carried past a projection region of said projection optical system to an exposure start position and thereafter makes said first position detector detect the relative positional relation between said mask and said photosensitive substrate in the two-dimensional directions perpendicular to said optical axis; and

a second controller which is connected to said first position detector and controls said first adjuster to adjust the relative positional relation between said mask and said photosensitive substrate in the two-dimensional directions perpendicular to the optical axis, based on the relative positional relation, detected by said first position detector, between said mask and said photosensitive substrate in the two-dimensional directions perpendicular to said optical axis, after said mask and said photosensitive substrate are carried to the exposure start position and before the exposure starts.

13. A scanning exposure apparatus according to claim 12, further comprising:

a third controller which controls said second adjuster to adjust the relative positional relation between said mask and said photosensitive substrate with respect to the direction of the optical axis, based on an output from said second position detector during scanning-exposure of said mask and said photosensitive substrate.

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

a memory which stores an amount of control of said second adjuster when said first controller controlled said second adjuster, at said predetermined alignment point;

wherein said third controller controls said second adjuster during said scanning-exposure, based on the output from said second position detector and the amount of control of said second adjuster stored in said memory.

30. A scanning exposure apparatus according to claim 12, further comprising:

a mask holder capable of moving while holding said mask; and

a substrate holder capable of moving while holding said photosensitive substrate,

wherein said first adjuster is connected to at least one of said mask holder and said substrate holder.

31. A scanning exposure apparatus according to claim 12, further comprising a substrate holder capable of moving while holding said photosensitive substrate,

wherein said second adjuster is connected to said substrate holder.

32. A scanning exposure apparatus according to claim 12, wherein said first and second position detectors are optical detectors.

19. A scanning exposure method for exposing patterns of a mask onto a photosensitive substrate, by holding said mask and said photosensitive substrate in such a manner that they face each other, and by moving them synchronously relative to a plurality of projection optical systems, the method comprising the steps of:

adjusting relative positional relation between said mask and said photosensitive substrate with respect to the directions of optical axes of said projection optical systems, at a predetermined alignment point while carrying said mask and said photosensitive substrate to an exposure start position;

detecting, after said adjusting, positional relation between said mask and said photosensitive substrate with respect to directions perpendicular to said optical axes, at said predetermined alignment point; and

adjusting the positional relation between said mask and said photosensitive substrate with respect to the directions perpendicular to said optical axes.

20. A scanning exposure method according to claim 19, wherein said mask and said photosensitive substrate are stopped at said predetermined alignment point.

21. A scanning exposure method according to claim 19, wherein said step of adjusting the positional relation between said mask and said photosensitive substrate with respect to the directions perpendicular to said optical axes, is carried out before exposure is started.

22. A scanning exposure method according to claim 19, further comprising the step of:

adjusting relative positional relation between said mask and said photosensitive substrate with respect to the directions of the optical axes of said projection optical systems, after adjusting the positional relation between said mask and said photosensitive substrate with respect to the directions perpendicular to said optical axes.

23. A scanning exposure method according to claim 22, wherein said step of adjusting relative positional relation between said mask and said photosensitive substrate with respect to the directions of the optical axes of said projection optical systems, is performed during exposure.

24. A scanning exposure method according to claim 23, wherein said step of adjusting relative positional relation between said mask and said photosensitive substrate with respect to the directions of the optical axes of said projection optical systems, is performed based on said adjusting which was performed at least at said predetermined alignment point.

25. A scanning exposure method according to claim 19, wherein said mask and said photosensitive substrate are moved in the same direction.

33. A scanning exposure method for moving a mask and a photosensitive substrate synchronously, and effecting scanning exposure of an image of patterns of said mask on said photosensitive substrate, the method comprising the steps of:

detecting relative positional relation between said mask and said photosensitive substrate while carrying said mask and said photosensitive substrate integrally in a direction opposite to the direction in which said scanning exposure is effected; and

correcting the relative positional relation between said mask and said photosensitive substrate, based on the relative positional relation between said mask and said photosensitive substrate obtained by said detecting step, while said mask and said photosensitive substrate are stopped at an exposure start position where said exposure is effected and/or during said exposure.

34. A liquid crystal display device which is manufactured by using the scanning exposure method according to claim 33.