Light source optimizing method, exposure method, device manufacturing method, program, exposure apparatus, lithography system, light source evaluation method, and light source modulation method

• US 9,551,938 B2
• Filed: 02/06/2012
• Issued: 01/24/2017
• Est. Priority Date: 02/20/2010
• Status: Active Grant

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Matsuyama, Tomoyuki, Kita, Naonori
• Primary Examiner(s): Persaud, Deoram
• Application Number:
  US13/366,829
• Publication Number:
  US 20120133915A1
• Time in Patent Office: 1,814 Days
• Field of Search: 355/67, 355/52
• US Class Current: 1/1
• CPC Class Codes: G03F 7/70116 Off-axis setting using a programmable means, e.g. liquid crystal display [LCD], digital micromirror device [DMD] or pupil facets
• CPC Class Codes: G03F 7/70125 Use of illumination settings tailored to particular mask patterns details of setting means G03F7/70091
• CPC Class Codes: G03F 7/705 Modelling or simulating from physical phenomena up to complete wafer processes or whole workflow in wafer productions
• CPC Class Codes: G03F 7/70625 Dimensions, e.g. line width, critical dimension [CD], profile, sidewall angle or edge roughness

Abstract

Disclosed is a light source optimizing method wherein: a light source shape obtained as the result of SMO is set as a target, the SMO being an optimizing calculation method for optimizing a mask pattern and illumination light source, a spatial light modulator is controlled such that a deviation from the target is within an acceptable range, and the shape of the illumination light source is set; the image of the pattern obtained as the results of the SMO is formed on a wafer, using illumination light emitted from the illumination light source having the set light source shape, an OPE is evaluated as image-forming performance using the detection results obtained by detecting the image of the pattern thus formed; and the light source shape is optimized.

Claims

1. An adjustment device used in an exposure apparatus that makes a light from a light source be distributed in an illumination pupil, illuminates a pattern with the light via the illumination pupil and exposes an object with an image of the pattern that has been illuminated, the device comprising:

a memory in which instructions are stored; and

a controller configured to execute the instructions stored in the memory causing the controller to execute;

expressing, by using a polynomial, a distribution of difference between a pupil intensity distribution in the illumination pupil and a target pupil intensity distribution serving as a target; and

calculating, by using a variation of an image-forming state measured after forming the image of the pattern on the object, a coefficient of each term of the polynomial such that the image-forming state falls within a predetermined acceptable range, wherein

the controller outputs an instruction for adjusting the pupil intensity distribution by using the coefficient obtained by the calculating.

2. The adjustment device according to claim 1, wherein

the controller executes the expressing and the calculating, with the adjusted pupil intensity distribution serving as the pupil intensity distribution.

3. The adjustment device according to claim 1, wherein

the polynomial comprises a polynomial in which a position in the illumination pupil is used as a variable.

4. The adjustment device according to claim 3, wherein

the polynomial comprises a transmittance modulation function T(ξ

,η

)≡

exp[Σ

_iZ_if_i(ξ

,η

)] defined using a Fringe Zernike polynomial f_i(ξ

η

) related to a position ξ

,η

in the illumination pupil and an expansion coefficient Z_i , of each order of the Fringe Zernike polynomial.

5. The adjustment device according to claim 3, wherein

the polynomial comprises a distortion polynomial ξ

′

=Σ

_iZ′

_i{D_i(ξ

,η

)·

Dξ

},η

′

=Σ

_iZ′

_i{D_i(ξ

,η

)·

Dη

}.

6. The adjustment device according to claim 1, wherein

in the calculating, a least-squares method is used.

7. The adjustment device according to claim 1, wherein

the image-forming state includes an error of a line width of the image of the pattern.

8. The adjustment device according to claim 1, wherein

the image-forming state includes an Optical Proximity Effect error.

9. The adjustment device according to claim 1, wherein

the image-forming state includes a process window.

10. The adjustment device according to claim 1, wherein

the polynomial includes a polynomial that is a Zernike polynomial multiplied by the target pupil intensity distribution.

11. The adjustment device according to claim 1, wherein

the polynomial includes a polynomial that is a distortion polynomial multiplied by the target pupil intensity distribution.

12. The adjustment device according to claim 1, wherein

the polynomial includes a convolution of a blur function that indicates an intensity distribution of blur and the target pupil intensity distribution.

13. The adjustment device according to claim 1, wherein

the polynomial includes a predetermined index function related to a modulation due to a flare component.

14. A device manufacturing method comprising:

forming a predetermined pattern on a substrate serving as the object, using an exposure apparatus adjusted with the adjustment device according to claim 1;

developing the substrate on which the predetermined pattern has been formed and forming a mask layer on a surface of the substrate, the mask layer having a shape corresponding to the predetermined pattern; and

processing the surface of the substrate via the mask layer.

15. A non-transitory computer-readable recording medium storing a program that causes a computer to execute at least a part of control of an exposure apparatus, the exposure apparatus making a light from a light source be distributed in an illumination pupil, illuminating a pattern with the light via the illumination pupil and exposing an object with an image of the pattern that has been illuminated, the program causing the computer to execute:

by using a polynomial, expressing a distribution of difference between a pupil intensity distribution in the illumination pupil and a target pupil intensity distribution that serves as a target; and

by using a variation of an image-forming state measured after forming the image of the pattern on the object, calculating a coefficient of each term of the polynomial such that the image-forming state falls within a predetermined acceptable range.

16. The non-transitory computer-readable recording medium according to claim 15, wherein

the polynomial comprises a polynomial in which a position in the illumination pupil is used as a variable.

17. The non-transitory computer-readable recording medium according to claim 16, wherein

the polynomial comprises a transmittance modulation function T(ξ

,η

)≡

exp[Σ

_iZ_if_i(ξ

,η

)] defined using a Fringe Zernike polynomial f_i(ξ

,η

) related to a position ξ

,η

in the illumination pupil and an expansion coefficient Z_i of each order of the Fringe Zernike polynomial.

18. The non-transitory computer-readable recording medium according to claim 16, wherein

the polynomial comprises a distortion polynomial ξ

′

=Σ

_iZ′

_i{D_i(ξ

,η

)·

Dξ

},η

′

=Σ

_iZ′

_i{D_i(ξ

,η

)·

Dη

}.

19. The non-transitory computer-readable recording medium according to claim 15, wherein

the image-forming state includes an error of a line width of the image of the pattern.

20. The non-transitory computer-readable recording medium according to claim 15, wherein

the image-forming state includes an Optical Proximity Effect error.

21. The non-transitory computer-readable recording medium according to claim 15, wherein

the image-forming state includes a process window.

22. The non-transitory computer-readable recording medium according to claim 15, wherein

the polynomial includes a polynomial that is a Zernike polynomial multiplied by the target pupil intensity distribution.

23. The non-transitory computer-readable recording medium according to claim 15, wherein

the polynomial includes a polynomial that is a distortion polynomial multiplied by the target pupil intensity distribution.

24. The non-transitory computer-readable recording medium according to claim 15, wherein

the polynomial includes a convolution of a blur function that indicates an intensity distribution of blur and the target pupil intensity distribution.

25. The non-transitory computer-readable recording medium according to claim 15, wherein

the polynomial includes a predetermined index function related to a modulation due to a flare component.

26. An exposure apparatus that makes a light from a light source be distributed in an illumination pupil, illuminates a pattern with the light via the illumination pupil and exposes an object with an image of the pattern that has been illuminated, the apparatus comprising:

a first calculation section that, by using a polynomial, expresses a distribution of difference between a pupil intensity distribution in the illumination pupil and a target pupil intensity distribution that serves as a target;

a second calculation section that, by using a variation of an image-forming state measured after forming the image of the pattern on the object, calculates a coefficient of each term of the polynomial such that the image-forming state falls within a predetermined acceptable range; and

an adjustment section that adjusts the pupil intensity distribution, by using the coefficient that has been calculated.

27. The exposure apparatus according to claim 26, wherein

the polynomial comprises a polynomial in which a position in the illumination pupil is used as a variable.

28. The exposure apparatus according to claim 27, wherein the polynomial comprises a transmittance modulation function T(ξ

,η

)≡

exp[Σ

_iZ_if_i(ξ

,η

)] defined using a Fringe Zernike polynomial f_i(ξ

,η

) related to a position ξ

η

in the illumination pupil and an expansion coefficient Z_i of each order of the Fringe Zernike polynomial.

29. The exposure apparatus according to claim 27, wherein

the polynomial comprises a distortion polynomial ξ

′

=Σ

_iZ′

_i{D_i(ξ

,η

)·

Dξ

},η

′

=Σ

_iZ′

_i{D_i(ξ

,η

)·

Dη

}.

30. The exposure apparatus according to claim 26, wherein

the image-forming state includes an error of a line width of the image of the pattern.

31. The exposure apparatus according to claim 26, wherein

the image-forming state includes an Optical Proximity Effect error.

32. The exposure apparatus according to claim 26, wherein

the image-forming state includes a process window.

33. The exposure apparatus according to claim 26, wherein

the polynomial includes a polynomial that is a Zernike polynomial multiplied by the target pupil intensity distribution.

34. The exposure apparatus according to claim 26, wherein

the polynomial includes a polynomial that is a distortion polynomial multiplied by the target pupil intensity distribution.

35. The exposure apparatus according to claim 26, wherein

the polynomial includes a convolution of a blur function that indicates an intensity distribution of blur and the target pupil intensity distribution.

36. The exposure apparatus according to claim 26, wherein

the polynomial includes a predetermined index function related to a modulation due to a flare component.

37. A lithography system that forms a pattern on a substrate, the system comprising:

the exposure apparatus according to claim 26; and

a controller that performs at least a part of control of the exposure apparatus.

38. A device manufacturing method comprising:

forming a predetermined pattern on a substrate serving as the object, using the lithography system according to claim 37;

developing the substrate on which the predetermined pattern has been formed and forming a mask layer on a surface of the substrate, the mask layer having a shape corresponding to the predetermined pattern; and

processing the surface of the substrate via the mask layer.