Exposure method and exposure apparatus

• US 20030138742A1
• Filed: 11/19/2002
• Published: 07/24/2003
• Est. Priority Date: 04/11/2000
• Status: Abandoned Application

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Irie, Nobuyuki, Magome, Nobutaka
• Application Number:
  US10/298,907
• Publication Number:
  US 20030138742A1
• Time in Patent Office: Days
• US Class Current: 430/396
• CPC Class Codes: G03F 7/201 characterised by an oblique exposure; characterised by the use of plural sources; characterised by the rotation of the optical device; characterised by a relative movement of the optical device, the light source, the sensitive system or the mask
• CPC Class Codes: G03F 7/70066 Size and form of the illuminated area in the mask plane, e.g. reticle masking blades or blinds
• CPC Class Codes: G03F 7/70191 Optical correction elements, filters or phase plates for controlling intensity, wavelength, polarisation, phase or the like
• CPC Class Codes: G03F 7/70358 Scanning exposure, i.e. relative movement of patterned beam and workpiece during imaging

Abstract

An exposure method which irradiates a slit-shaped illumination light IL on a reticle Ri and a substrate while moving them synchronously so as to sequentially transfer images of patterns formed on the reticle Ri to the substrate 4, wherein a density filter Fj having an attenuating part for gradually reducing the distribution of illuminance of the illumination light IL is moved in synchronization with the movement of the reticle Ri.

Claims

1. An exposure method which irradiates a slit-shaped energy beam on a mask and a sensitive object while moving them synchronously so as to sequentially transfer images of patterns formed on the mask to the sensitive object, including

a step of moving a density filter having an attenuating part for gradually reducing an amount of energy of the energy beam in synchronization with the movement of the mask.

2. An exposure method as set forth in claim 1, wherein a light-blocking member able to advance into and retract from said energy beam is moved in synchronization with movement of said density filter.

3. An exposure method as set forth in claim 2, wherein said light-blocking member is moved in a state positioned to block part of the density filter.

4. An exposure method as set forth in claim 1, wherein part of said attenuating part is selectively blocked by a light-blocking member able to advance into and retract from said energy beam.

5. An exposure method as set forth in claim 1, wherein different areas on said sensitive object are irradiated by said energy beam for seamless exposure such that parts irradiated by said energy beam on said sensitive object through said attenuating part overlap as stitched parts.

6. An exposure method as set forth in claim 5, wherein different areas on said sensitive object in a direction along a direction of movement of said sensitive object are irradiated by said energy beam.

7. An exposure method as set forth in claim 6, wherein different areas on said sensitive object in a direction perpendicular to said direction of movement are irradiated by said energy beam.

8. An exposure method as set forth in claim 5, wherein a pattern obtained by enlarging a pattern for transfer is partitioned into patterns of a plurality of masks and images of said masks reduced by a projection optical system are successively transferred to a plurality of areas on said sensitive object with partially overlapping peripheral parts.

16. A photomask produced using the exposure method of claim 1.

17. A method of manufacture of a device including a step of transferring a pattern for transfer to a device substrate using a photomask of claim 16.

9. An exposure method which relatively moves a mask and a sensitive object with respect to an energy beam and scans and exposes the sensitive object by the energy beam through the mask, including

a step of gradually reducing an amount of energy in a part of an area irradiated by the energy beam on the sensitive object in a first direction in which the sensitive object is moved, while relatively moving a slope part where the amount of energy is gradually reduced in the first direction in said irradiated area during the scan exposure.

10. An exposure method as set forth in claim 9, wherein the slope part is moved in a state of corresponding substantially with a part to which an amount of exposure energy in the first direction of a predetermined area by which scan exposure is carried out on the sensitive object reduces.

11. An exposure method as set forth in claim 9, wherein the slope part is moved in a state of corresponding substantially with a part of a predetermined area, which partially overlaps an area adjacent to the predetermined area in the first direction.

12. An exposure method as set forth in claim 9, wherein a density filter having an attenuating part for forming the slope part is made to relatively move with respect to said energy beam in accordance with movement of said mask.

13. An exposure method as set forth in claim 12, wherein a relative positional relationship between a blocking member for blocking said energy beam and said density filter is adjusted before the scan exposure.

14. An exposure method as set forth in claim 9, wherein the slope part is moved relatively in the first direction in the irradiated area when scanning and exposing at least two areas arranged in the first direction out of a plurality of areas for transferring patterns to the plurality of areas on the sensitive object with partially overlapping peripheral parts by a step-and-stitch system.

15. An exposure method as set forth in claim 14, wherein the amount of energy in the irradiated area is made to be gradually reduced relative to a second direction perpendicular to the first direction in order to scan and expose at least two areas aligned in the second direction out of said plurality of areas.

18. An exposure apparatus which irradiates a slit-shaped energy beam on a mask and a sensitive object while moving them synchronously so as to sequentially transfer images of patterns formed on the mask to the sensitive object, comprising

a density filter which adjusts the distribution of energy of the energy beam and

a filter stage which moves the density filter in synchronization with the mask.

34. A method of manufacture of a photomask including a step of transferring a plurality of patterns on a mask substrate by a step-and-stitch method using an exposure apparatus of claim 18.

35. A method of manufacture of a photomask as set forth in claim 34, where said plurality of patterns are obtained by partitioning an enlarged pattern of a device pattern to be formed on the photomask into a plurality of patterns and wherein images of them reduced by a projection optical system are transferred on a plurality of areas partially overlapping at their peripheral parts on the mask substrate.

39. An exposure apparatus as set forth in claim 18, further comprising a detector which detects positional information of said density filter, and wherein a position of said density filter is set based on said positional information.

40. An exposure apparatus as set froth in claim 39, further comprising a setting device which sets a positional relationship of said mask and said density filter based on the positional information detected by said detector.

19. An exposure apparatus comprising:

a mask stage which moves a mask,

a substrate stage which moves a substrate,

an illumination optical system which irradiates a slit-shaped energy beam,

a filter stage which moves a density filter having an attenuating part for gradually reducing an amount of energy of said energy beam, and

a controller which controls said mask stage, said substrate stage, and said filter stage so that said substrate and said density filter move synchronously with respect to said energy beam.

20. An exposure apparatus as set forth in claim 19, further comprising

a blind mechanism having a light-blocking member able to advance and retract in a direction along the direction of movement of the mask,

said controller controlling the blind mechanism so that said light-blocking member moves synchronously with said density filter in a state maintaining a predetermined positional relationship with said density filter.

21. An exposure apparatus which relatively moves a mask and a sensitive object with respect to an energy beam and scans and exposes the sensitive object by the energy beam through the mask, comprising:

a density filter which gradually reduces an amount of energy in a part of an area irradiated by the energy beam on the sensitive object in a first direction in which the sensitive object is moved and

an adjuster which shifts a slope part where the amount of energy is gradually reduced in the first direction in said irradiated area during the scan exposure.

22. An exposure apparatus as set forth in claim 21, wherein said adjuster includes a drive mechanism which moves said density filter relative to said energy beam in accordance with movement of said mask.

23. An exposure apparatus as set forth in claim 21, wherein at least two areas on said sensitive object with partially overlapped peripheral parts and aligned in said first direction are scanned and exposed for transferring patterns on said at least two areas by the step-and-stitch system.

24. An exposure apparatus as set forth in claim 23, wherein said density filter gradually reduces the amount of energy in said irradiated area at an end in said second direction so as to scan and expose at least two areas which partially overlap at their peripheral parts on the sensitive object and are aligned in a second direction perpendicular to said first direction.

25. An exposure apparatus in which a mask and a sensitive object are moved relative to an energy beam and the sensitive object is scanned exposed by the energy beam through the mask, comprising:

a first optical unit which defines the width of an area irradiated by the energy beam on the sensitive object in a first direction in which the sensitive object is moved during the scan exposure; and

a second optical unit which gradually reduces an amount of energy in a part of the irradiated area in the first direction, while shifting a slope part which the amount of energy is gradually reduced in the first direction within the irradiated area during the scan exposure.

26. An exposure apparatus as set forth in claim 25, wherein the second optical unit shifts the slope part in a state of corresponding substantially with a part which an amount of exposure energy in the first direction of a predetermined area by which scan exposure is carried out on the sensitive object reduces.

27. An exposure apparatus as set forth in claim 25, wherein the second optical unit shifts the slope part in a state of corresponding substantially with a part of a predetermined area, which partially overlaps an area adjacent to the predetermined area in the first direction.

28. An exposure apparatus as set forth in claim 25, wherein the second optical unit includes a density filter having an attenuating part for forming the slope part and the density filter is shifted synchronously with movement of the mask and the sensitive object.

29. An exposure apparatus as set forth in claim 28, wherein the first optical unit includes a stop member having an opening width thereof fixed in the first direction and the density filter has a light shielding part formed adjacent to the attenuating part in the first direction and whose width is equal to or larger than the opening width of the stop member.

30. An exposure apparatus as set forth in claim 28, wherein the first optical unit includes a movable stop member which prevents an area outside the slope from being irradiated with the energy beam in the first direction in the irradiated area and at least a part of the movable stop member is moved in accordance with movement of the density filter.

31. An exposure apparatus as set forth in claim 30, wherein the first optical unit includes a stop member different from the movable stop member and having a fixed opening width in the first direction.

32. An exposure apparatus as set forth in claim 28, wherein the density filter gradually decreases the amount of energy at the end of the irradiated area in a second direction perpendicular to the first direction.

33. An exposure apparatus as set forth in claim 25, wherein the first optical unit gradually reduces the amount of energy at the end of the irradiated area in the first direction.

36. An exposure apparatus as set forth in claim 28, further comprising a setting device which detects positional information of said density filter and sets a position of said density filter based on said positional information.

37. An exposure apparatus as set forth in claim 28, further comprising a setting device which detects positional information of said density filter and sets a positional relationship of said mask and said density filter based on said positional information.

38. An exposure apparatus as set froth in claim 28, wherein said density filter is formed by a large number of dot patterns wherein said attenuating parts are arranged at different pitches.

41. An exposure apparatus for illuminating an energy beam on a mask and exposing a sensitive object by said energy beam through said mask, comprising

a density filter arranged in an illumination system through which said energy beam passes, the density filter gradually decreasing an energy amount in a part of an illumination region of said energy beam on said sensitive object;

and

a detector which detects positional information of said density filter inside said illumination system.

42. An exposure apparatus as set forth in claim 41, further comprising a setting device which sets a position of said density filter based on the positional information detected by said detector.

43. An exposure apparatus as set forth in claim 42, wherein said setting device sets a positional relationship of said mask and said density filter.

44. An exposure apparatus as set forth in claim 41, wherein said density filter is formed by a large number of dot patterns wherein said attenuating parts are arranged at different pitches.

45. An exposure method which irradiates a slit-shaped energy beam on a mask and a sensitive object while moving them synchronously along a first direction so as to sequentially transfer images of patterns formed on the mask to the sensitive object, including

a first step for irradiating the energy beam wherein a width in said first direction is made to be constant, and

a second step for irradiating the energy beam while moving a light-blocking member capable of advancing into and retracting from said energy beam to change the width of the first direction of the energy beam as a whole over a second direction which is perpendicular to the first direction so that a cumulative energy distribution on said sensitive object becomes a slant at least either of immediately before and immediately after performing said first step.

46. An exposure method as set forth in claim 45, wherein different areas on said sensitive object in said first direction are respectively subjected to said first and second steps such that parts irradiated by said energy beam on said sensitive object by said second step overlap as stitched parts.

47. An exposure method as set forth in claim 45, wherein said energy beam is irradiated through a light-attenuating filter for attenuating in a slanting fashion an amount of energy of said energy beam at least at one of two ends of the energy beam in said second direction as getting closer to the end.

48. An exposure method as set forth in claim 45, wherein said energy beam is irradiated through a slit plate for narrowing the width of the energy beam in the first direction in a slanting fashion as getting closer to the end at least at one of both ends of the energy beam in said second direction.

49. An exposure method as set forth in claim 47 or 48, wherein different areas on said sensitive object in said second direction are respectively subjected to said first and second steps such that parts irradiated by said energy beam through said light attenuating filter or said slit plate overlap as stitched parts on said sensitive object.

50. An exposure method as set forth in claim 45, wherein an enlarged pattern of a pattern to be transferred is divided to a plurality of mask patterns and reduced images by a projection optical system of said masks are sequentially transferred to a plurality of areas in which peripheral parts partially overlap on said sensitive object.

51. A photomask produced by using the exposure method as set forth in claim 45.

52. A method of producing a device including a step of using the photomask as set forth in claim 51 and transferring an image of a pattern formed on the photomask on a device substrate.

53. An exposure apparatus which irradiates a slit-shaped energy beam on a mask and a sensitive object while moving them synchronously in a first direction so as to sequentially transfer images of patterns formed on the mask to the sensitive object, comprising

a blind mechanism having a light-blocking member capable of advancing into and retracting from said energy beam in said first direction, and

a controller which controls said blind mechanism such that a cumulative energy distribution on said sensitive object becomes a slant during at least either of a predetermined period immediately after starting irradiation and a predetermined period immediately before the end of irradiation of said energy beam.

54. An exposure apparatus as set forth in claim 53, wherein different areas on said sensitive object in said first direction are irradiated said energy beam such that parts where a cumulative energy distribution on said sensitive object is set to be a slant overlap as stitching parts.

55. An exposure apparatus as set forth in claim 53, further comprising a light-attenuating filter which attenuates an amount of energy of said energy beam in a slanting fashion as getting closer to the end at least at one of both ends of the energy beam in said second direction.

56. An exposure apparatus as set forth in claim 53, further comprising a slit plate which narrows in a slanting fashion a width of said energy beam in the first direction at least at one of ends of the energy beam in said second direction as getting closer to the end.

57. An exposure apparatus as set froth in claim 55 or 56, wherein different areas on said sensitive object are irradiated said energy beam in a second direction which is perpendicular to said first direction such that parts irradiated by said energy beam through said light-attenuating filter or said slit plate overlap as stitching parts on said sensitive object.

58. An exposure apparatus as set forth in claim 53, comprising

a mask stage which moves said mask and

a substrate stage which moves a substrate, and

wherein said controller controls said mask stage, said substrate stage and said blind mechanism such that said mask, said substrate and said light-blocking member move in synchronization with said energy beam.

59. An exposure apparatus as set forth in claim 58, wherein

said light-blocking member comprises a plurality of light-blocking plates which independently moves in said first direction, and

said controller moves at least one of said plurality of light-blocking plates in said first direction in synchronization with said mask.

60. A method of producing a photomask, including a step of transferring a plurality of patterns on a mask substrate in a step-and-stitch method by using the exposure apparatus as set forth in claim 53.

61. A method of producing a photomask as set forth in claim 60, wherein said plurality of patterns are a plurality of divided enlarged pattern of a device pattern to be formed on said photomask and reduced images by a projection optical system are respectively transferred on a plurality of areas in which peripheral parts partially overlap on said mask substrate.