Light source optimizing method, exposure method, device manufacturing method, program, exposure apparatus, lithography system, light source evaluation method, and light source modulation method
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.
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 i Z i f i (ξ,η)] defined using a Fringe Zernike polynomial f i (ξη) 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 i Z′ i {D i (ξ,η)·Dξ},η′=Σ i Z′ 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 i Z i f 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 i Z′ i {D i (ξ,η)·Dξ},η′=Σ i Z′ 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 i Z i f i (ξ,η)] defined using a Fringe Zernike polynomial f i (ξ,η) related to a position ξη 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 i Z′ i {D i (ξ,η)·Dξ},η′ =Σ i Z′ 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.