Photomask for projection lithography at or below about 160 nm and a method thereof

• US 6,395,433 B1
• Filed: 10/08/1999
• Issued: 05/28/2002
• Est. Priority Date: 10/08/1998
• Status: Expired due to Term

• Current Assignee: Rochester Institute of Technology
• Original Assignee: Rochester Institute of Technology
• Inventors: Smith, Bruce W.
• Primary Examiner(s): Huff, Mark F.
• Assistant Examiner(s): Mohamedulla, Saleha R.
• Application Number:
  US09/415,149
• Time in Patent Office: 963 Days
• Field of Search: 430/5,322 378/34,35
• US Class Current: 430/5
• CPC Class Codes: G03F 1/32 Attenuating PSM [att-PSM], e.g. halftone PSM or PSM having semi-transparent phase shift portion,; Preparation thereof
• CPC Class Codes: G03F 1/46 Antireflective coatings

Abstract

An attenuated phase shift mask for use in a lithography process includes a masking film made of at least one material with at least a silicon component which provides a transmission above about 0.5 percent and a phase shift of about a 180° for radiation at a wavelength at or below about 160 nm.

Claims

1. A mask for use in a lithography process, the mask comprising a masking film made of at least one material with at least a silicon component which provides an attenuated transmission above about 0.5 percent up to about 40 percent and a phase shift of about 180°

for radiation at a wavelength at or below about 160 nm.

2. The mask as set forth in claim 1 wherein the material is selected from a group consisting of silicon, silicon dioxide, and silicon nitride.

3. The mask as set forth in claim 1 wherein the material is made of at least one metallic oxide with silicon dioxide.

4. The mask as set forth in claim 3 wherein the metallic oxide is selected from a group consisting of oxides of Ta, Hf, Sn, Mo, Ti, Fe, Ru, W, Mn, Cu, Cr, Ni, V, Nb, In, and Co.

5. The mask as set forth in claim 1 wherein the material is made of at least one metallic nitride with silicon nitride.

6. The mask as set forth in claim 5 wherein the metallic nitride is selected from a group consisting of nitrides of Hf, Ta, Mo, Sn, Ti, Fe, Ru, Mn, Cu, Cr, Ni, V, Nb, In, and Co.

7. The mask as set forth in claim 1 wherein the masking film comprise s a single layer.

8. The mask as set forth in claim 1 wherein the masking film comprises multiple layers.

9. The mask as set forth in claim 1 wherein the masking film allows for transmission up to about 20% at wavelengths up to about 400 nm.

10. The mask as set forth in claim 1 wherein the masking film has a thickness ranging between about 200 and 2000 Å

in thickness.

11. The mask as set forth in claim 1 further comprising a substrate made with at least one material with a fluoride component, the masking film located on at least a portion of the substrate.

12. The mask as set forth in claim 1 further comprising a substrate which comprises fused silica with a fluoride film overcoat, the masking film located on at least a portion of the substrate.

13. The mask as set forth in claim 1 wherein the selectivity between the masking film and an underlying substrate is above 10:

1.

14. The mask as set forth in claim 1 further comprising an anti-reflective layer located on the masking film.

15. The mask as set forth in claim 14 wherein the anti-reflective layer comprises a silicon based dielectric material coated to a quarter wave thickness to reduce reflectivity below 10%.

62. The mask as set forth in claim 1 further comprising a substrate.

63. The mask as set forth in claim 62 wherein the etch selectivity between the substrate and the masking film is below 10:

1.

16. An attenuated phase shift mask comprising:

a substrate with at least one surface; and

a masking film on at least a portion of the one surface of the substrate, the masking film is made of at least one material with at least a silicon component which provides an attenuated transmission above about 0.5 percent up to about 40 percent and a phase shift of about a 180°

for radiation at a wavelength at or below about 160 nm.

17. The mask as set forth in claim 16 wherein the material is selected from a group consisting of silicon, silicon dioxide, and silicon nitride.

18. The mask as set forth in claim 16 wherein the material is made of at least one metallic oxide with silicon dioxide.

19. The mask as set forth in claim 18 wherein the metallic oxide is selected from a group consisting of oxides of Ta, Hf, Sn, Mo, Ti, Fe, Ru, W, Mn, Cu, Cr, Ni, V, Nb, In, and Co.

20. The mask as set forth in claim 16 wherein the material is made of at least one metallic nitride with silicon nitride.

21. The mask as set forth in claim 20 wherein the metallic nitride is selected from a group consisting of nitrides of Hf, Ta, Mo, Sn, Ti, Fe, Ru, Mn, Cu, Cr, Ni, V, Nb, In, and Co.

22. The mask as set forth in claim 16 wherein the masking film comprises a single layer.

23. The mask as set forth in claim 16 wherein the masking film comprises multiple layers.

24. The mask as set forth in claim 16 wherein the masking film allows for transmission up to about 20% at wavelengths up to about 400 nm.

25. The mask as set forth in claim 16 wherein the masking film has a thickness ranging between about 200 and 2000 Å

in thickness.

26. The mask as set forth in claim 16 wherein the substrate is made with at least one material with a fluoride component.

27. The mask as set forth in claim 16 wherein the substrate comprises fused silica with a fluoride film overcoat.

28. The mask as set forth in claim 16 wherein the selectivity between the masking film and the substrate is above 10:

1.

29. The mask as set forth in claim 16 further comprising an anti-reflective layer located on the masking film.

30. The mask as set forth in claim 29 wherein the anti-reflective layer comprises a silicon based dielectric material coated to a quarter wave thickness to reduce reflectivity below 10%.

31. A method for lithography comprising:

placing a masking film over at least a portion of one surface of a substrate, the masking film made of at least one material with at least a silicon component; and

exposing the masking film and the substrate to radiation at a wavelength at or below about 160 nm, wherein the masking film provides an attenuated transmission above about 0.5 percent up to about 40 percent and a phase shift of about a 180°

for radiation at a wavelength at or below about 160 nm.

32. The method as set forth in claim 31 further comprising etching the masking film using an etch chemistry prior to the step of exposing.

33. The method as set forth in claim 31 wherein the masking film and the substrate are made of materials which are not substantially etched in the same etch chemistry.

34. The method as set forth in claim 31 wherein the masking film is deposited onto the one surface of the substrate by vapor deposition.

35. The method as set forth in claim 31 wherein the material is selected from a group consisting of silicon, silicon dioxide, and silicon nitride.

36. The method as set forth in claim 31 wherein the masking film is made of at least one metallic oxide.

37. The method as set forth in claim 36 wherein the metallic oxide is selected from a group consisting of oxides of Ta, Hf, Sn, Mo, Ti, Fe, Ru, W, Mn, Cu, Cr, Ni, V, Nb, In, and Co with silicon dioxide.

38. The method as set forth in claim 31 wherein the masking film is made of at least one metallic nitride.

39. The method as set forth in claim 38 wherein the metallic nitride is selected from a group consisting of nitrides of Hf, Ta, Mo, Sn, Ti, Fe, Ru, Mn, Cu, Cr, Ni, V, Nb, In, and Co with silicon nitride.

40. The method as set forth in claim 31 wherein the substrate is made with at least one material with a fluoride component.

41. The method as set forth in claim 31 wherein the substrate comprises fused silica with a fluoride film overcoat.

42. The method as set forth in claim 31 further comprising placing an anti-reflective layer on the masking film.

43. The method as set forth in claim 42 wherein the anti-reflective layer comprises a silicon based dielectric material coated to a quarter wave thickness to reduce reflectivity below 10%.

44. A mask for use in a lithography process, the mask comprising a masking film made of at least silicon which provides an attenuated transmission above about 0.5 up to about 40 percent for radiation at a wavelength at or below about 160 nm.

45. The mask as set forth in claim 44 further comprising a substrate made with at least one material with a fluoride component, the masking film located on at least a portion of the substrate.

46. The mask as set forth in claim 44 wherein the selectivity between the masking film and an underlying substrate is above 10:

1.

47. The mask as set forth in claim 44 further comprising an anti-reflective layer located on the masking film.

48. The mask as set forth in claim 47 wherein the anti-reflective layer comprises a silicon based dielectric material coated to a quarter wave thickness to reduce reflectivity below 10%.

49. A mask comprising:

a substrate with at least one surface; and

a masking film on the one surface of the substrate, the masking film comprising silicon which provides an attenuated transmission above about 0.5 percent up to about 40 percent for radiation at a wavelength at or below about 160 nm.

50. The mask as set forth in claim 49 wherein the substrate is made with at least one material with a fluoride component.

51. The mask as set forth in claim 49 wherein the selectivity between the masking film and the substrate is above 10:

1.

52. The mask as set forth in claim 49 further comprising an anti-reflective layer located on the masking film.

53. The mask as set forth in claim 49 wherein the anti-reflective layer comprises a silicon based dielectric material coated to a quarter wave thickness to reduce reflectivity below 10%.

54. A method for lithography comprising:

placing a masking film over at least a portion of one surface of a substrate, the masking film comprising silicon; and

exposing the masking film to radiation at a wavelength at or below about 160 nm, wherein the masking film provides an attenuated transmission above about 0.5 percent up to about 40 percent for radiation at a wavelength at or below about 160 nm.

55. The method as set forth in claim 54 further comprising etching the masking film using an etch chemistry prior to the step of exposing.

56. The method as set forth in claim 54 wherein the masking film and the substrate are made of materials which are not substantially etched in the same etch chemistry.

57. The method as set forth in claim 54 wherein the masking film is deposited onto the one surface of the substrate by vapor deposition.

58. The method as set forth in claim 54 wherein the substrate is made with at least one material with a fluoride component.

59. The method as set forth in claim 54 wherein the substrate comprises fused silica with a fluoride film overcoat.

60. The method as set forth in claim 54 further comprising placing an anti-reflective layer on the masking film.

61. The method as set forth in claim 60 wherein the anti-reflective layer comprises a silicon based dielectric material coated to a quarter wave thickness to reduce reflectivity below 10%.