Photomask, pattern formation method using the same and mask data creation method

Abstract

A principal pattern made of a plurality of isolated transparent portions is formed in a light-shielding portion disposed on a transparent substrate having a transparent property against exposing light. The principal pattern includes a first principal pattern and a second principal pattern adjacent to each other at a given distance, and a first auxiliary pattern made of a phase shifter portion for transmitting the exposing light in an opposite phase to the exposing light passing through the transparent portion is formed between the first principal pattern and the second principal pattern.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a diagram for showing the shape of a desired resist pattern to be formed by using a photomask according to Embodiment 1 of the invention and FIG. 1B is a plan view of the photomask of Embodiment 1;

FIGS. 2A and 2B are diagrams of mask patterns used in simulation for an effect of an auxiliary pattern made of a phase shifter portion used in the photomask of Embodiment 1 of the invention;

FIGS. 3A, 3B and 3C are diagrams for showing results of the simulation for the effect of the auxiliary pattern made of the phase shifter portion used in the photomask of Embodiment 1 of the invention;

FIGS. 4A, 4B and 4C are diagrams obtained by converting the abscissa of the graphs of the simulation results shown in FIGS. 3A through 3C into a principal pattern space;

FIGS. 5A and 5B are diagrams for showing mask patterns used in simulation for an effect of an auxiliary pattern for transmitting light in the same phase with respect to a transparent portion in the photomask of Embodiment 1 of the invention;

FIGS. 6A, 6B and 6C are diagrams for showing results of the simulation for the effect of the auxiliary pattern for transmitting light in the same phase with respect to the transparent portion in the photomask of Embodiment 1 of the invention;

FIGS. 7A, 7B and 7C are diagrams obtained by converting the abscissa of the graphs of the simulation results shown in FIGS. 6A through 6C into a principal pattern space;

FIGS. 8A, 8B and 8C are diagrams for showing results of simulation for an effect of an auxiliary pattern made of a semi-light-shielding portion used in the photomask of Embodiment 1 of the invention;

FIG. 9 is a diagram of a mask pattern used in simulation for the effect of the auxiliary pattern made of a semi-light-shielding portion used in the photomask of Embodiment 1 of the invention;

FIGS. 10A, 10B and 10C are diagrams for showing results of the simulation for the effect of the auxiliary pattern made of a semi-light-shielding portion used in the photomask of Embodiment 1 of the invention;

FIGS. 11A, 11B and 11C are diagrams for explaining the range of appropriate transmittance of a semi-light-shielding portion used as an auxiliary pattern in the photomask of Embodiment 1 of the invention;

FIGS. 12A, 12B, 12C and 12D are diagrams for showing various cross-sectional structures of a portion corresponding to line AB of the photomask of Embodiment 1 of the invention shown in FIG. 1B and FIG. 12E is a diagram for showing an exemplified cross-sectional structure of a portion corresponding to line AB of a reflection mask according to a modification of Embodiment 1 of the invention shown in FIG. 1B;

FIG. 13A is a diagram for showing the shape of a desired resist pattern to be formed by using a photomask according to a modification of Embodiment 1 of the invention and FIG. 13B is a plan view of the photomask according to the modification of Embodiment 1 of the invention;

FIG. 14A is a diagram for showing the shape of a desired resist pattern to be formed by using a photomask according to a modification of Embodiment 1 of the invention and FIG. 14B is a plan view of the photomask according to the modification of Embodiment 1 of the invention;

FIG. 15A is a diagram for showing the shape of a desired resist pattern to be formed by using a photomask according to Embodiment 2 of the invention and FIG. 15B is a plan view of the photomask according to Embodiment 2 of the invention;

FIG. 16 is a plan view of a photomask according to a modification of Embodiment 2 of the invention;

FIGS. 17A, 17B, 17C and 17D are cross-sectional views for showing procedures in a pattern formation method according to Embodiment 3 of the invention;

FIG. 18A is a diagram for schematically showing a general exposure light source and FIGS. 18B, 18C and 18D are diagrams for schematically showing light sources for oblique incident illumination;

FIG. 19 is a flowchart of a basic flow of a mask data creation method according to Embodiment 4 of the invention;

FIG. 20A is a diagram of an exemplified desired pattern to be formed by using a photomask of Embodiment 4 of the invention and FIG. 20B is a diagram of an exemplified specific mask pattern created in one procedure in the mask data creation method of Embodiment 4 of the invention;

FIGS. 21A and 21B are diagrams of exemplified mask patterns created in procedures in the mask data creation method of Embodiment 4 of the invention;

FIGS. 22A and 22B are diagrams of exemplified mask patterns created in other procedures in the mask data creation method of Embodiment 4 of the invention;

FIG. 23 is a diagram of an exemplified specific mask pattern obtained by the mask data creation method according to Embodiment 4 of the invention;

FIG. 24 is a flowchart of a basic flow of a mask data creation method according to Embodiment 5 of the invention;

FIGS. 25A and 25B are diagrams of exemplified specific mask patterns created in procedures in the mask data creation method of Embodiment 5 of the invention;

FIGS. 26A and 26B are diagrams of exemplified specific mask patterns created in other procedures in the mask data creation method of Embodiment 5 of the invention;

FIGS. 27A and 27B are diagrams of exemplified specific mask patterns created in other procedures in the mask data creation method of Embodiment 5 of the invention;

FIG. 28 is a diagram of an exemplified specific mask pattern obtained by the mask data creation method according to Embodiment 5 of the invention; and

FIGS. 29A and 29B are plan views of conventional photomasks.

Claims

1. A photomask comprising a principal pattern made of a plurality of isolated transparent portions and formed in a light-shielding portion disposed on a transparent substrate having a transparent property against exposing light, wherein said principal pattern includes a first principal pattern and a second principal pattern adjacent to each other at a given distance, anda first auxiliary pattern made of a phase shifter portion for transmitting the exposing light in an opposite phase to the exposing light passing through said transparent portion is formed between said first principal pattern and said second principal pattern.

2. The photomask of claim 1, wherein a single phase shifter portion is provided, as said first auxiliary pattern, between said first principal pattern and said second principal pattern with a part of said light-shielding portion sandwiched between each of said first principal pattern and said second principal pattern and said first auxiliary pattern.

3. The photomask of claim 1, wherein a second auxiliary pattern made of a semi-light-shielding portion for partially transmitting the exposing light in the same phase to the exposing light passing through said transparent portion is formed on a side, opposite to said first auxiliary pattern, of at least one of said first principal pattern and said second principal pattern.

4. A photomask comprising a principal pattern made of a plurality of isolated transparent portions and formed in a light-shielding portion disposed on a transparent substrate having a transparent property against exposing light, wherein said principal pattern includes a first principal pattern, a second principal pattern adjacent to said first principal pattern at a first distance and a third principal pattern adjacent to said first principal pattern at a second distance larger than said first distance,an auxiliary pattern made of a semi-light-shielding portion for partially transmitting the exposing light in the same phase to the exposing light passing through said transparent portion is formed between said first principal pattern and said third principal pattern, andan auxiliary pattern made of the semi-light-shielding portion is not formed between said first principal pattern and said second principal pattern.

5. A photomask comprising a principal pattern made of a plurality of isolated transparent portions and formed in a light-shielding portion disposed on a transparent substrate having a transparent property against exposing light, wherein said principal pattern includes a first principal pattern, a second principal pattern adjacent to said first principal pattern at a first distance and a third principal pattern adjacent to said first principal pattern at a second distance larger than said first distance,a first auxiliary pattern made of a phase shifter portion for transmitting the exposing light in an opposite phase to the exposing light passing through said transparent portion is formed between said first principal pattern and said second principal pattern, andan auxiliary pattern made of the phase shifter portion is not formed between said first principal pattern and said third principal pattern.

6. The photomask of claim 5, wherein a single phase shifter portion is provided, as said first auxiliary pattern, at a center between said first principal pattern and said second principal pattern with a part of said light-shielding portion sandwiched between each of said first principal pattern and said second principal pattern and said first auxiliary pattern.

7. The photomask of claim 5, wherein said first distance is not more than 0.8×M×λ/NA (wherein λ indicates a wavelength of the exposing light and M and NA respectively indicate a reduction ratio and numerical aperture of a reduction projection optical system of a projection aligner).

8. The photomask of claim 5, wherein said first auxiliary pattern has a width not more than 0.4×M×λ/NA (wherein λ indicates a wavelength of the exposing light and M and NA respectively indicate a reduction ratio and numerical aperture of a reduction projection optical system of a projection aligner).

9. The photomask of claim 5, wherein a second auxiliary pattern for transmitting the exposing light in the same phase to the exposing light passing through said transparent portion is formed between said first principal pattern and said third principal pattern.

10. The photomask of claim 9, wherein said second auxiliary pattern is singly provided between said first principal pattern and said third principal pattern with a part of said light-shielding portion sandwiched between each of said first principal pattern and said third principal pattern and said second auxiliary pattern.

11. The photomask of claim 9, wherein said second distance is not less than 1.0×M×λ/NA (wherein λ indicates a wavelength of the exposing light and M and NA respectively indicate a reduction ratio and numerical aperture of a reduction projection optical system of a projection aligner).

12. The photomask of claim 9, wherein said second auxiliary pattern transmits the exposing light in a phase difference not less than (−30+360×n) degrees and not more than (30+360×n) degrees with respect to said transparent portion (wherein n is an integer).

13. The photomask of claim 9, wherein said second auxiliary pattern is made of a semi-light-shielding portion for partially transmitting the exposing light.

14. The photomask of claim 13, wherein said semi-light-shielding portion is made of a metal thin film with a thickness of 30 nm or less.

15. The photomask of claim 13, wherein said second auxiliary pattern has a region that is away from said first principal pattern by a distance not less than 0.3×M×λ/NA and not more than 0.8×M×λ/NA (wherein λ indicates a wavelength of the exposing light and M and NA respectively indicate a reduction ratio and numerical aperture of a reduction projection optical system of a projection aligner).

16. The photomask of claim 13, wherein said semi-light-shielding portion has transmittance of 20% or less against the exposing light.

17. The photomask of claim 16, wherein said second auxiliary pattern has a region that has a width not less than 0.4×M×λ/NA (wherein λ indicates a wavelength of the exposing light and M and NA respectively indicate a reduction ratio and numerical aperture of a reduction projection optical system of a projection aligner).

18. The photomask of claim 9, wherein said second auxiliary pattern is made of another transparent portion.

19. The photomask of claim 5, wherein said phase shifter portion transmits the exposing light in a phase difference not less than (150+360×n) degrees and not more than (210+360×n) degrees with respect to said transparent portion (wherein n is an integer).

20. The photomask of claim 19, wherein said phase shifter portion is formed by trenching said transparent substrate.

21. A photomask comprising at least two or more principal patterns made of a plurality of isolated transparent portions and formed in a light-shielding portion disposed on a transparent substrate having a transparent property against exposing light, wherein said light-shielding portion surrounds said principal patterns,a semi-light-shielding portion for partially transmitting the exposing light in the same phase to the exposing light passing through said transparent portion is provided so as to surround an outline of said light-shielding portion, andat least one auxiliary pattern having a transparent property against the exposing light is provided between said principal patterns so as to be surrounded with said light-shielding portion.

22. The photomask of claim 21, wherein a portion of said light-shielding portion sandwiched between each of said principal patterns and said semi-light-shielding portion has a region that has a width not less than 0.3×M×λ/NA and not more than 0.8×M×λ/NA (wherein λ indicates a wavelength of the exposing light and M and NA respectively indicate a reduction ratio and numerical aperture of a reduction projection optical system of a projection aligner).

23. The photomask of claim 21, wherein said auxiliary pattern is made of a phase shifter portion for transmitting the exposing light in an opposite phase to the exposing light passing through said transparent portion.

24. The photomask of claim 23, wherein said auxiliary pattern is provided for a distance between said principal patterns not more than 0.8×M×λ/NA (wherein λ indicates a wavelength of the exposing light and M and NA respectively indicate a reduction ratio and numerical aperture of a reduction projection optical system of a projection aligner).

25. The photomask of claim 23, wherein said auxiliary pattern has a width not more than 0.4×M×λ/NA (wherein λ indicates a wavelength of the exposing light and M and NA respectively indicate a reduction ratio and numerical aperture of a reduction projection optical system of a projection aligner).

26. The photomask of claim 23, wherein said phase shifter portion transmits the exposing light in a phase difference not less than (150+360×n) degrees and not more than (210+360×n) degrees with respect to said transparent portion (wherein n is an integer).

27. The photomask of claim 26, wherein said phase shifter portion is formed by trenching said transparent substrate.

28. The photomask of claim 21, wherein said auxiliary pattern is made of another transparent portion.

29. The photomask of claim 28, wherein said auxiliary pattern is provided for a distance between said principal patterns not less than 1.0×M×λ/NA (wherein λ indicates a wavelength of the exposing light and M and NA respectively indicate a reduction ratio and numerical aperture of a reduction projection optical system of a projection aligner).

30. The photomask of claim 21, wherein said semi-light-shielding portion transmits the exposing light in a phase difference not less than (−30+360×n) degrees and not more than (30+360×n) degrees with respect to said transparent portion (wherein n is an integer).

31. The photomask of claim 21, wherein said semi-light-shielding portion is made of a metal thin film with a thickness of 30 nm or less.

32. A photomask comprising a principal pattern made of a plurality of isolated reflection portions for reflecting exposing light and formed in a non-reflection portion disposed on a substrate, wherein said principal pattern includes a first principal pattern and a second principal pattern adjacent to each other at a given distance, anda first auxiliary pattern made of a phase shifter portion for reflecting the exposing light in an opposite phase to the exposing light reflected by said reflection portion is formed between said first principal pattern and said second principal pattern.

33. The photomask of claim 32, wherein a single phase shifter portion is provided, as said first auxiliary pattern, between said first principal pattern and said second principal pattern with a part of said non-reflection portion sandwiched between each of said first principal pattern and said second principal pattern and said auxiliary pattern.

34. The photomask of claim 32, wherein a second auxiliary pattern made of a semi-reflection portion for partially reflecting the exposing light in the same phase to the exposing light reflected by said reflection portion is formed on a side, opposite to said first auxiliary pattern, of at least one of said first principal pattern and said second principal pattern.

35. A photomask comprising a principal pattern made of a plurality of isolated reflection portions for reflecting exposing light and formed in a non-reflection portion disposed on a substrate, wherein said principal pattern includes a first principal pattern, a second principal pattern adjacent to said first principal pattern at a first distance and a third principal pattern adjacent to said first principal pattern at a second distance larger than said first distance,an auxiliary pattern made of a semi-reflection portion for partially reflecting the exposing light in the same phase to the exposing light reflected by said reflection portion is formed between said first principal pattern and said third principal pattern, andan auxiliary pattern made of the semi-reflection portion is not formed between said first principal pattern and said second principal pattern.

36. A photomask comprising a principal pattern made of a plurality of isolated reflection portions for reflecting exposing light and formed in a non-reflection portion disposed on a substrate, wherein said principal pattern includes a first principal pattern, a second principal pattern adjacent to said first principal pattern at a first distance and a third principal pattern adjacent to said first principal pattern at a second distance larger than said first distance,a first auxiliary pattern made of a phase shifter portion for reflecting the exposing light in an opposite phase to the exposing light reflected by said reflection portion is formed between said first principal pattern and said second principal pattern, andan auxiliary pattern made of the phase shifter portion is not formed between said first principal pattern and said third principal pattern.

37. The photomask of claim 36, wherein a second auxiliary pattern for reflecting the exposing light in the same phase to the exposing light reflected by said reflection portion is formed between said first principal pattern and said third principal pattern.

38. The photomask of claim 37, wherein said second auxiliary pattern is made of a semi-reflection portion for partially reflecting the exposing light.

39. A photomask comprising at least two or more principal patterns made of a plurality of isolated reflection portions for reflecting exposing light and formed in a non-reflection portion disposed on a substrate, wherein said non-reflection portion surrounds said principal patterns,a semi-reflection portion for partially reflecting the exposing light in the same phase to the exposing light reflected by said reflection portion is provided so as to surround an outline of said non-reflection portion, andat least one auxiliary pattern having a reflecting property against the exposing light is provided between said principal patterns so as to be surrounded with said non-reflection portion.

40. The photomask of claim 39, wherein said auxiliary pattern is made of a phase shifter portion for reflecting the exposing light in an opposite phase to the exposing light reflected by said reflection portion.

41. The photomask of claim 39, wherein said auxiliary pattern is made of another reflection portion.

42. A pattern formation method using the photomask of claim 1, comprising the steps of: (a) forming a resist film on a substrate;(b) irradiating said resist film with the exposing light through said photomask; and(c) forming a resist pattern by developing said resist film having been irradiated with the exposing light.

43. The pattern formation method of claim 42, wherein oblique incident illumination is employed in the step (b).

44. A mask data creation method for setting, in a photomask for use in exposure, an exposed region for transmitting or reflecting exposing light and an unexposed region for neither transmitting nor reflecting the exposing light, comprising the steps of: (a) setting, as principal patterns of said exposed region, a plurality of regions corresponding to desired exposed portions of a resist formed by irradiating said resist with the exposing light through said photomask;(b) setting a background of said photomask as said unexposed region; and(c) setting, as an auxiliary pattern having an opposite phase, a region in an opposite phase relationship with said principal patterns in a portion where a distance between said plurality of regions set as said principal patterns is not more than a first distance.

45. The mask creation method of claim 44, further comprising a step of setting, as an auxiliary pattern having the same phase, a region in the same phase relationship with said principal patterns in a portion where the distance between said plurality of regions set as said principal patterns is not less than a second distance.

46. The mask data creation method of claim 45, wherein said auxiliary pattern having the same phase has transmittance or reflectance of 3% or more and 20% or less against the exposing light with respect to said principal patterns.

47. A mask data creation method for setting, in a photomask for use in exposure, an exposed region for transmitting or reflecting exposing light and an unexposed region for neither transmitting nor reflecting the exposing light, comprising the steps of: (a) setting, as principal patterns of said exposed region, a plurality of regions corresponding to desired exposed portions of a resist formed by irradiating said resist with the exposing light through said photomask;(b) setting a background of said photomask as a semi-light-shielding pattern or a semi-reflection pattern that has transmittance or reflectance of 3% or more and 20% or less against the exposing light with respect to said principal patterns and corresponds to a part of said exposed region;(c) setting a light-shielding pattern or a non-reflection pattern as said unexposed region for surrounding said principal patterns; and(d) setting, as an auxiliary pattern having an opposite phase, a region in an opposite phase relationship with said principal patterns in a portion where a distance between said plurality of regions set as said principal patterns is not more than a first distance.

48. The mask data creation method of claim 47, further comprising a step of setting, as an auxiliary pattern having the same phase, a region in the same phase relationship with said principal patterns in a portion where the distance between said plurality of regions set as said principal patterns is not less than a second distance.

49. The mask data creation method of claim 44, further comprising a step of creating a mask pattern for realizing a desired resist pattern by deforming shapes of said principal patterns after setting said auxiliary pattern.

50. The mask data creation method of claim 47, further comprising a step of creating a mask pattern for realizing a desired resist pattern by deforming shapes of said principal patterns after setting said auxiliary pattern.