Method and apparatus for exposure, and device manufacturing method

• US 20020146628A1
• Filed: 06/05/2002
• Published: 10/10/2002
• Est. Priority Date: 07/07/2000
• Status: Active Grant

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Ota, Kazuya
• Granted Patent: US 6,699,630 B2
• Time in Patent Office: Days
• US Class Current: 430/22
• 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 7/70425 Imaging strategies, e.g. for increasing throughput or resolution, printing product fields larger than the image field or compensating lithography- or non-lithography errors, e.g. proximity correction, mix-and-match, stitching or double patterning
• CPC Class Codes: G03F 7/70875 Temperature, e.g. temperature control of masks or workpieces via control of stage temperature

Abstract

On sequentially transferring patterns formed on a mask onto a plurality of divided areas on a substrate, when a new divided area on the substrate exposed, the substrate is moved from the exposure position of the preceding divided area to the exposure position of the new divided area in consideration of thermal expansion of the substrate at this stage. Thereafter, the mask pattern is transferred onto the predetermined divided area. With this process, exposure is performed with the respective shot areas arranged on the substrate at a desired interval in a cooled state after exposure. This makes it possible to improve the overlay accuracy with respect to the subsequent layer while performing exposure with high overlay accuracy with respect to the preceding layer.

Claims

1. An exposure method which sequentially transfer a pattern formed on a mask onto a plurality of divided areas arranged on a substrate along a predetermined direction, in an exposure sequence that proceeds to an adjacent divided area in said predetermined direction, said exposure method comprising:

correcting a movement information so as to make a correction amount of a movement amount of said substrate smaller than a correction amount of a movement amount of said substrate on preceding exposure, and adjusting a positional relationship between said mask and said substrate for exposure of a next divided area; and

exposing said next divided area.

2. The exposure method according to claim 1, wherein

said divided areas are arranged on said substrate in a shape of a matrix,

said exposure sequence proceeds to said adjacent divided area in a first row direction of said matrix, and when there is no adjacent divided area in said first row direction then goes on to an adjacent row in a column direction of said matrix, and continues in a second row direction which is opposite to said first row direction, and

said method further comprises increasing said correction amount of said movement amount of said substrate as exposure sequence proceeds to said adjacent row in said column direction.

3. The exposure method according to claim 1, further comprising:

obtaining said movement information prior exposure on said substrate.

4. The exposure method according to claim 3, wherein said obtaining said movement information comprises:

detecting positional information of a plurality of predetermined alignment marks which are among a plurality of alignment marks formed on said substrate with said plurality of divided areas; and

obtaining positional information of said plurality of divided areas formed on said substrate by statistical calculation based on a result of said detecting.

5. The exposure method according to claim 1, wherein said correction amount of said movement information is obtained in consideration of thermal expansion of said substrate when said substrate is moving.

6. The exposure method according to claim 5, wherein said correction amount of said movement information is determined on an assumption that of an exposure already performed on a predetermined layer, a thermal energy generated on an exposure which is performed spatially and temporally close to an exposure which performed on said divided area causes a local thermal expansion of said substrate, and a thermal energy generated on an exposure which is performed spatially and temporally far away from said exposure to be performed causes thermal expansion of said substrate in general.

7. The exposure method according to claim 1, which prior to exposure on said substrate, further comprising:

transferring sequentially measurement patterns on a plurality of measurement divided areas on a measurement substrate in accordance only with designed intervals between said measurement divided areas before transferring of said measurement substrate;

cooling said measurement substrate on which said measurement patterns are transferred to a temperature prior to said transfer, and measuring distances in between said measurement divided areas; and

determining said correction amount of said movement information based on a result of said measurement.

8. The exposure method according to claim 1, wherein an image characteristic of a transferred image of said pattern onto said substrate is controlled based on said correction amount of said movement information.

9. The exposure method according to claim 1, wherein

said pattern formed on said mask is transferred onto said substrate while synchronously moving said mask and said substrate, and

at least one of a starting position of said mask which moves synchronously on exposure of said divided area, a starting position said substrate which moves synchronously, a synchronous velocity ratio between said mask and said substrate, a direction of said mask moving synchronously, a direction of said substrate moving synchronously, and a rotational angle of said mask around a normal to a surface which said patterns are formed, is corrected with respect to said correction amount of said movement information.

29. A device manufacturing method including a lithographic process, wherein said lithographic process uses an exposure method in claim 1 to transfer a predetermined pattern onto a divided area on a substrate.

10. An exposure method which sequentially transfers a predetermined pattern on a plurality of divided areas arranged on a substrate in a shape of a matrix in a sequence that proceeds to an adjacent divided area in a first row direction of said matrix and when there is no adjacent divided area in said first row direction then goes on to an adjacent row in a column direction of said matrix and continues in a second row direction, said second row direction being a direction opposite to said first row direction, said exposure method which comprises:

correcting a movement information so as to make a correction amount of a movement amount of said substrate larger than a correction amount of a movement amount of said substrate on a preceding movement between rows, and adjusting a positional relationship between said mask and said substrate for exposure of a first divided area on a new row; and

transferring a pattern onto said first divided area on said new row.

11. The exposure method according to claim 10, further comprising

obtaining said movement information prior to exposure on said substrate.

12. The exposure method according to claim 11, wherein said movement information is obtained by

detecting positional information of a plurality of predetermined alignment marks which are among a plurality of alignment marks formed on said substrate with said plurality of divided areas, and

obtaining positional information of said plurality of divided areas formed on said substrate by statistical calculation based on a result of said detecting.

13. The exposure method according to claim 10, wherein a correction amount of said movement information is determined in consideration of thermal expansion of said substrate when said substrate is moving.

14. The exposure method according to claim 13, wherein a correction amount of said movement information is determined based on thermal energy generated by an exposure already performed on a predetermined layer on said substrate.

15. The exposure method according to claim 14, wherein a correction amount of said movement information is determined by a function using a number of divided areas in which exposure is already performed on said predetermined layer as a variable.

16. The exposure method according to claim 14, wherein said correction amount of said movement information is determined on an assumption that of an exposure already performed on said predetermined layer, a thermal energy generated on an exposure which is performed spatially and temporally close to an exposure to be performed on said divided area causes a local thermal expansion of said substrate, and a thermal energy generated on an exposure which is performed spatially and temporally far away from said exposure to be performed causes thermal expansion of said substrate in general.

17. The exposure method according to claim 10, which prior to exposure on said substrate further comprises:

transferring sequentially measurement patterns on a plurality of measurement divided areas on a measurement substrate in accordance only with designed intervals between said measurement divided areas before transferring of said measurement substrate;

cooling said measurement substrate on which said measurement patterns are transferred to a temperature prior to said transfer, and measuring distances in between said measurement divided areas; and

determining said correction amount of said movement information based on a result of said measurement.

18. The exposure method according to claim 10, wherein an image characteristic of a transferred image of said pattern onto said substrate is controlled based on said correction amount of said movement information.

19. The exposure method according to claim 10, wherein

said pattern formed on said mask is transferred onto said substrate while synchronously moving said mask and said substrate, and

at least one of a starting position of said mask which moves synchronously on exposure of said divided area, a starting position said substrate which moves synchronously, a synchronous velocity ratio between said mask and said substrate, a direction of said mask moving synchronously, a direction of said substrate moving synchronously, and a rotational angle of said mask around a normal to a surface which said patterns are formed, is corrected with respect to said correction amount of said movement information.

30. A device manufacturing method including a lithographic process, wherein said lithographic process uses an exposure method in claim 10 to transfer a predetermined pattern onto a divided area on a substrate.

20. A scanning exposure method which sequentially transfers a pattern formed on a mask onto a plurality of divided areas arranged on a substrate while synchronously moving said mask and said substrate, said exposure method comprising:

controlling a condition for scanning exposure on a predetermined layer in accordance with thermal energy generated by an exposure already performed on said predetermined layer on said substrate.

21. An exposure method which sequentially transfers a pattern formed on a mask onto a plurality of divided areas arranged on a substrate, said method comprising:

making a correction of a movement of said substrate on exposure of a predetermined layer on an assumption that of an exposure already performed on said predetermined layer, a thermal energy generated on an exposure which is performed spatially and temporally close to an exposure to be performed on said divided area causes a local thermal expansion of said substrate, and a thermal energy generated on an exposure which is performed spatially and temporally far away from said exposure to be performed causes thermal expansion of said substrate in general.

22. An exposure apparatus which sequentially transfer a pattern formed on a mask onto a plurality of divided areas arranged on a substrate along a predetermined direction, in an exposure sequence that proceeds to an adjacent divided area in said predetermined direction, said exposure apparatus comprising:

a substrate stage which holds said substrate; and

a movement control unit which corrects a movement information so as to make a correction amount of a movement amount of said substrate smaller than a correction amount of a movement amount of said substrate on preceding exposure, and adjusting a positional relationship between said mask and said substrate for exposure of a next divided area.

23. The exposure apparatus according to claim 22, wherein

said divided areas are arranged on said substrate in a shape of a matrix,

said exposure sequence proceeds to said adjacent divided area in a first row direction of said matrix, and when there is no adjacent divided area in said first row direction then goes on to an adjacent row in a column direction of said matrix, and continues in a second row direction, which is opposite to said first row direction, and

said movement control unit increases said correction amount of said movement amount of said substrate as exposure sequence proceeds to said adjacent row in said column direction.

24. The exposure apparatus according to claim 22, further comprising a measuring unit which measures said movement information prior to exposure of said substrate.

25. The exposure apparatus according to claim 24, wherein said measuring unit comprises:

a position detection unit which detects positional information of a plurality of predetermined alignment marks which are among a plurality of alignment marks formed on said substrate with said plurality of divided areas; and

a calculation unit which calculates positional information of said plurality of divided areas formed on said substrate by statistical calculation based on a result of said detecting.

26. The exposure apparatus according to claim 23, further comprising an image characteristic control system which controls an image characteristic of a transferred image of said pattern onto said substrate based on said correction amount of said movement information.

27. The exposure apparatus according to claim 26, wherein said image characteristic control system comprises:

a synchronous moving mechanism which synchronously moves said mask and said substrate on exposure of said divided areas; and

a synchronous movement control mechanism which controls at least one of a starting position of said mask which moves synchronously on exposure of said divided area, a starting position said substrate which moves synchronously, a synchronous velocity ratio between said mask and said substrate, a direction of said mask moving synchronously, a direction of said substrate moving synchronously, and a rotational angle of said mask around a normal to a surface which said patterns are formed, is corrected with respect to said correction amount of said movement information.

28. An exposure apparatus which sequentially transfers a pattern formed on a mask onto a plurality of divided areas arranged on a substrate in a shape of a matrix in a sequence that proceeds to an adjacent divided area in a first row direction of said matrix, and when there is no adjacent divided area in said first row direction then goes on to an adjacent row in a column direction of said matrix, and continues in a second row direction, said second row direction which is opposite to said first row direction, said exposure apparatus comprising:

a substrate stage which holds said substrate; and

a movement control unit which corrects a movement information so as to make a correction amount of a movement amount of said substrate larger than a correction amount of a movement amount of said substrate on a preceding movement between rows, and adjusting a positional relationship between said mask and said substrate for exposure of a first divided area on a new row.