Photomask, method for producing the same, and method for forming pattern using the photomask

• US 7,060,398 B2
• Filed: 12/24/2002
• Issued: 06/13/2006
• Est. Priority Date: 12/26/2001
• Status: Expired due to Fees

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Misaka, Akio
• Primary Examiner(s): ROSASCO, STEPHEN D
• Application Number:
  US10/474,336
• Publication Number:
  US 20040121244A1
• Time in Patent Office: 1,267 Days
• Field of Search: 430/5, 716/19, 716/21
• US Class Current: 430/5
• CPC Class Codes: G03F 1/29 Rim PSM or outrigger PSM; Preparation thereof
• CPC Class Codes: G03F 1/30 Alternating PSM, e.g. Levenson-Shibuya PSM; Preparation thereof
• CPC Class Codes: G03F 1/32 Attenuating PSM [att-PSM], e.g. halftone PSM or PSM having semi-transparent phase shift portion,; Preparation thereof

Abstract

A mask pattern to be provided on a transparent substrate 2 includes a semi-light-shielding portion 3 which transmits exposure light in the same phase as that of the light-transmitting portion 4 and a phase shifter 5 which transmits exposure light in a phase opposite to that of the light-transmitting portion 4. The semi-light-shielding portion 3 has a transmittance which allows exposure light to be partially transmitted. The phase shifter 5 is provided in a region of the mask pattern in which light transmitted through the phase shifter 5 can cancel part of the light transmitted through the light-transmitting portion 4 and the semi-light-transmitting portion 3.

Claims

1. A photomask in which, on a transparent substrate having light transmitting properties with respect to exposure light, a mask pattern having a semi-light shielding portion and a phase shifter, and a light-transmitting portion where the mask pattern is not located are provided, characterized in that

the semi-light shielding portion has a transmittance which allows the exposure light to be partially transmitted, and transmits the exposure light in the same phase as that of the light-transmitting portion,

the phase shifter transmits the exposure light in a phase opposite to that of the light-transmitting portion,

the mask pattern is provided so as to surround the light-transmitting portion, the phase shifter is formed in a ring-shape around the light-transmitting portion, and

the outline of the ring-shaped phase shifter is similar to the outline of the light-transmitting portion.

2. The photomask of claim 1, characterized in that the phase shifter is provided in contact with the light-transmitting portion.

3. The photomask of claim 1, characterized in that

the phase shifter is provided apart from the light-transmitting portion, and

a ring-shaped part of the semi-light shielding portion is formed between the light-transmitting portion and the phase shifter.

4. The photomask of claim 1, characterized in that the transmittance of the semi-light-transmitting portion with respect to the exposure light is 15% or less.

5. The photomask of claim 1, characterized in that the transmittance of the semi-light-transmitting portion with respect to the exposure light is 6% or more and 15% or less.

6. The photomask of claim 1, characterized in that the semi-light-shielding portion transmits the exposure light with a phase difference of (−

30+360×

n) degrees or more and (30+360×

n) degrees or less (where n=an integer) with respect to light transmitted through the light-transmitting portion and the phase shifter transmits the exposure light with a phase difference of (150+360×

n) degrees or more and (210+360×

n) degrees or less (where n=an integer) with respect to light transmitted through the light-transmitting portion.

7. The photomask of claim 1, characterized in that the phase shifter is disposed in a region of the mask pattern extending from the boundary with the light-transmitting portion by a distance of (0.8×

λ

/NA)×

M or less (where λ

is the wavelength of the exposure light, and NA and M are the numerical aperture and reduction ratio of a reduction projection optical system of an exposure apparatus, respectively).

8. The photomask of claim 1, characterized in that the width of the phase shifter is (0.3×

λ

/NA)×

M or less (where λ

is the wavelength of the exposure light, and NA and M are the numerical aperture and reduction ratio of a reduction projection optical system of an exposure apparatus, respectively).

9. The photomask of claim 1, characterized in that

the light-transmitting portion is an exposed region of the surface of the transparent substrate,

the phase shifter is a region in which a first phase shifter, which transmits the exposure light in a phase opposite to that of the light-transmitting portion, is formed on the transparent substrate, and

the semi-light shielding portion is a region in which a multilayer film composed of the first phase shifter and a second phase shifter, which transmits the exposure light in a phase opposite to that of the first phase shifter, is formed on the transparent substrate.

10. The photomask of claim 1, characterized in that

the light-transmitting portion is an exposed region of the surface of the transparent substrate,

the phase shifter is a region dug to a predetermined depth in the transparent substrate such that exposure light is transmitted in a phase opposite to that of the light-transmitting portion, and

the semi-light shielding portion is a region in which a semi-light shielding film, which transmits the exposure light in the same phase as that of the light-transmitting portion, is formed on the transparent substrate.

11. The photomask of claim 1, characterized in that

the phase shifter is an exposed region of the surface of the transparent substrate,

the light-transmitting portion is a region dug to a predetermined depth in the transparent substrate such that exposure light is transmitted in a phase opposite to that of the phase shifter, and

the semi-light shielding portion is a region in which a phase shifter film, which transmits the exposure light a phase opposite to that of the phase shifter, is formed on the transparent substrate.

12. The photomask of claim 1, characterized in that

the light-transmitting portion is an exposed region of the surface of the transparent substrate,

the phase shifter is a region dug to a predetermined depth in the transparent substrate such that exposure light is transmitted in a phase opposite to that of the light-transmitting portion, and

the semi-light shielding portion is a region in which a thinned light-shielding film, which transmits the exposure light in the same phase as that of the light-transmitting portion, is formed on the transparent substrate.

13. The photomask of claim 1, characterized in that

the light-transmitting portion is an exposed region of the surface of the transparent substrate,

the semi-light shielding portion is a region in which a semi-light shielding film, which transmits the exposure light in the same phase as that of the light-transmitting portion, is formed on the transparent substrate, and

the phase shifter is a region dug to a predetermined depth in the semi-light shielding film such that exposure light is transmitted in a phase opposite to that of the light-transmitting portion.

14. The photomask of claim 1, characterized in that

the light-transmitting portion is an exposed region of the surface of the transparent substrate,

the semi-light shielding portion is a region in which a semi-light shielding film, which transmits the exposure light in the same phase as that of the light-transmitting portion, is formed on the transparent substrate, and

the phase shifter is a region in which a multilayer film composed of the semi-light shielding film and a phase shifter film, which transmits the exposure light in a phase opposite to that of the light-transmitting portion, is formed on the transparent substrate.

15. A photomask in which, on a transparent substrate having light transmitting properties with respect to exposure light, a mask pattern having a semi-light shielding portion and a phase shifter, and a light-transmitting portion where the mask pattern is not located are provided, characterized in that

the semi-light shielding portion has a transmittance which allows the exposure light to be partially transmitted, and transmits the exposure light in the same phase as that of the light-transmitting portion,

the phase shifter transmits the exposure light in a phase opposite to that of the light-transmitting portion,

the mask pattern is provided so as to surround the light-transmitting portion, and

the phase shifter is composed of a plurality of phase shifter portions formed in the periphery of the light-transmitting portion.

16. The photomask of claim 15, characterized in that

the light-transmitting portion is formed in a quadrangular shape, and

the phase shifter is composed of four quadrangular phase shifter portions respectively formed in the vicinity of an associated side of the light-transmitting portion.

17. The photomask of claim 16, characterized in that each phase shifter portion is formed in contact with the associated side of the light-transmitting portion.

18. The photomask of claim 16, characterized in that

each phase shifter portion is formed apart from the associated side of the light-transmitting portion, and

a part of the semi-light shielding portion is formed between each phase shifter portion and the light-transmitting portion.

19. The photomask of claim 15, characterized in that

the light-transmitting portion is formed in a quadrangular shape, and

the phase shifter is composed of four quadrangular phase shifter portions each having the same length as an associated side of the light-transmitting portion, and is formed in contact with each associated side of the light-transmitting portion.

20. The photomask of claim 15, characterized in that

the light-transmitting portion is formed in a quadrangular shape, and

the phase shifter is composed of four quadrangular phase shifter portions each having a length shorter than an associated side of the light-transmitting portion, and is formed in contact with each associated side of the light-transmitting portion.

21. The photomask of claim 20, characterized in that the center of the associated side of the light-transmitting portion is aligned with the center of the respective phase shifter portion of the phase shifter formed in contact therewith.

22. The photomask of claim 15, characterized in that

the light-transmitting portion is formed in a quadrangular shape, and

the phase shifter is composed of four quadrangular phase shifter portions each having a length longer than an associated side of the light-transmitting portion, and is formed apart from each associated side of the light-transmitting portion.

23. The photomask of claim 22, characterized in that

each phase shifter portion of the phase shifter is formed such that a corner is in contact with an associated corner of another phase shifter portion on the diagonal line of the light-transmitting portion, and

a part of the semi-light shielding portion is formed between the phase shifter and the light-transmitting portion.

24. The photomask of claim 15, characterized in that

the light-transmitting portion is formed in a quadrangular shape,

the phase shifter is composed of four quadrangular phase shifter portions each having a length shorter than an associated side of the light-transmitting portion, and is formed apart from each associated side of the light-transmitting portion, and

a part of the semi-light shielding portion is formed between the phase shifter and the light-transmitting portion.

25. The photomask of claim 15, characterized in that the transmittance of the semi-light-transmitting portion with respect to the exposure light is 15% or less.

26. The photomask of claim 15, characterized in that the transmittance of the semi-light-transmitting portion with respect to the exposure light is 6% or more and 15% or less.

27. The photomask of claim 15, characterized in that the semi-light-shielding portion transmits the exposure light with a phase difference of (−

30+360×

n) degrees or more and (30+360×

n) degrees or less (where n=an integer) with respect to light transmitted through the light-transmitting portion and the phase shifter transmits the exposure light with a phase difference of (150+360×

n) degrees or more and (210+360×

n) degrees or less (where n=an integer) with respect to light transmitted through the light-transmitting portion.

28. The photomask of claim 15, characterized in that the phase shifter is disposed in a region of the mask pattern extending from the boundary with the light-transmitting portion by a distance of (0.8×

λ

/NA)×

M or less (where λ

is the wavelength of the exposure light, and NA and M are the numerical aperture and reduction ratio of a reduction projection optical system of an exposure apparatus, respectively).

29. The photomask of claim 15, characterized in that the width of the phase shifter is (0.3×

λ

/NA)×

M or less (where λ

is the wavelength of the exposure light, and NA and M are the numerical aperture and reduction ratio of a reduction projection optical system of an exposure apparatus, respectively).

30. The photomask of claim 15, characterized in that

the light-transmitting portion is an exposed region of the surface of the transparent substrate,

the phase shifter is a region in which a first phase shifter, which transmits the exposure light in a phase opposite to that of the light-transmitting portion, is formed on the transparent substrate, and

the semi-light shielding portion is a region in which a multilayer film composed of the first phase shifter and a second phase shifter, which transmits the exposure light in a phase opposite to that of the first phase shifter, is formed on the transparent substrate.

31. The photomask of claim 15, characterized in that

the light-transmitting portion is an exposed region of the surface of the transparent substrate,

the phase shifter is a region dug to a predetermined depth in the transparent substrate such that exposure light is transmitted in a phase opposite to that of the light-transmitting portion, and

the semi-light shielding portion is a region in which a semi-light shielding film, which transmits the exposure light in the same phase as that of the light-transmitting portion, is formed on the transparent substrate.

32. The photomask of claim 15, characterized in that

the phase shifter is an exposed region of the surface of the transparent substrate,

the light-transmitting portion is a region dug to a predetermined depth in the transparent substrate such that exposure light is transmitted in a phase opposite to that of the phase shifter, and

the semi-light shielding portion is a region in which a phase shifter film, which transmits the exposure light in a phase opposite to that of the phase shifter, is formed on the transparent substrate.

33. The photomask of claim 15, characterized in that

the light-transmitting portion is an exposed region of the surface of the transparent substrate,

the phase shifter is a region dug to a predetermined depth in the transparent substrate such that exposure light is transmitted in a phase opposite to that of the light-transmitting portion, and

the semi-light shielding portion is a region in which a thinned light-shielding film, which transmits the exposure light in the same phase as that of the light-transmitting portion, is formed on the transparent substrate.

34. The photomask of claim 15, characterized in that

the light-transmitting portion is an exposed region of the surface of the transparent substrate,

the semi-light shielding portion is a region in which a semi-light shielding film, which transmits the exposure light in the same phase as that of the light-transmitting portion, is formed on the transparent substrate, and

the phase shifter is a region dug to a predetermined depth in the semi-light shielding film such that exposure light is transmitted in a phase opposite to that of the light-transmitting portion.

35. The photomask of claim 15, characterized in that

the light-transmitting portion is an exposed region of the surface of the transparent substrate,

the semi-light shielding portion is a region in which a semi-light shielding film, which transmits the exposure light in the same phase as that of the light-transmitting portion, is formed on the transparent substrate, and

the phase shifter is a region in which a multilayer film composed of the semi-light shielding film and a phase shifter film, which transmits the exposure light in a phase opposite to that of the light-transmitting portion, is formed on the transparent substrate.

36. The photomask of claim 15, characterized in that

the light-transmitting portion includes a first light-transmitting portion and a second light-transmitting portion,

the mask pattern is provided so as to surround the first light-transmitting portion and the second light-transmitting portion, and

the phase shifter is provided in a center portion of the mask pattern located between the first light-transmitting portion and the second light-transmitting portion, and the semi-light shielding portion is provided in each of both sides of the phase shifter.

37. The photomask of claim 36, characterized in that the space between the first light-transmitting portion and the second light-transmitting portion is (0.8×

λ

/NA)×

M or less (where λ

is the wavelength of the exposure light, and NA and M are the numerical aperture and reduction ratio of a reduction projection optical system of an exposure apparatus, respectively).

38. The photomask of claim 37, characterized in that the width of the phase shifter is (0.4×

λ

/NA)×

M or less.

39. The photomask of claim 15, characterized in that each phase shifter portion is formed in contact with the light-transmitting portion.

40. The photomask of claim 15, characterized in that

each phase shifter portion is formed apart from the light-transmitting portion, and

a part of the semi-light shielding portion is formed between the phase shifter and the light-transmitting portion.