Metal alloys for the reflective or the semi-reflective layer of an optical storage medium

• US 20060172108A1
• Filed: 03/28/2006
• Published: 08/03/2006
• Est. Priority Date: 04/18/2003
• Status: Active Grant

• Current Assignee: Target Technology Company LLC
• Original Assignee: Target Technology Company LLC
• Inventors: Nee, Han H.
• Granted Patent: US 7,645,500 B2
• Time in Patent Office: Days
• US Class Current: 428/64.400
• CPC Class Codes: C22C 1/06 with the use of special agents for refining or deoxidising
• CPC Class Codes: C22C 5/06 Alloys based on silver
• CPC Class Codes: C22C 5/08 with copper as the next major constituent
• CPC Class Codes: C22C 5/10 with cadmium as the next major constituent
• CPC Class Codes: C23C 14/185 by cathodic sputtering
• CPC Class Codes: G11B 2007/0006 adapted for scanning different types of carrier, e.g. CD & DVD
• CPC Class Codes: G11B 2007/0013 for carriers having multiple discrete layers
• CPC Class Codes: G11B 2007/24312 group 14 elements (e.g. Si, Ge, Sn)
• CPC Class Codes: G11B 2007/24314 group 15 elements (e.g. Sb, Bi)
• CPC Class Codes: G11B 2007/24316 group 16 elements (i.e. chalcogenides, Se, Te)
• CPC Class Codes: G11B 2007/2582 based on silver
• CPC Class Codes: G11B 7/00454 involving phase-change effects
• CPC Class Codes: G11B 7/006 Overwriting G11B7/0065 takes precedence
• CPC Class Codes: G11B 7/24038 Multiple laminated recording layers
• CPC Class Codes: G11B 7/24062 Reflective layers
• CPC Class Codes: G11B 7/24085 Pits
• CPC Class Codes: G11B 7/243 comprising inorganic materials only, e.g. ablative layers
• CPC Class Codes: G11B 7/258 of reflective layers
• CPC Class Codes: G11B 7/259 based on silver
• CPC Class Codes: G11B 7/266 Sputtering or spin-coating layers sputtering in general C23C14/24; spin-coating in general B05D1/005
• CPC Class Codes: G11C 13/041 : using photochromic storage elements G11C13/042 takes precedence
• CPC Class Codes: Y10T 428/21 : Circular sheet or circular blank
• CPC Class Codes: Y10T 428/24521 : with component conforming to contour of nonplanar surface
• CPC Class Codes: Y10T 428/24545 : Containing metal or metal compound

Abstract

A silver-based alloy thin film is provided for the highly reflective or semi-reflective coating layer of optical discs. Elements that can be added to silver to produce useful silver alloys include zinc, aluminum, copper, manganese, germanium, yttrium, bismuth, scandium, and cobalt. These alloys have moderate to high reflectivity and reasonable corrosion resistance in the ambient environment.

Claims

1. An optical storage medium, comprising:

a first layer having a pattern of features in at least one major surface;

a reflective coating;

said reflective coating including a metal alloy, said metal alloy including silver and yttrium, wherein the relationship between the amounts of silver and yttrium in the metal alloy is defined by Ag_xY_w where 0.9500<

x<

0.9999 and 0.0001<

w<

0.05, wherein said reflective coating is about 60 nanometers thick or less.

2. The optical storage medium of claim 1, wherein 0.001<

w<

0.03.

3. The optical storage medium of claim 1, wherein said reflective coating is about 40 nanometers thick or less.

4. The optical storage medium of claim 1, wherein said reflective coating is about 30 nanometers thick or less.

5. The optical storage medium of claim 1, wherein said first layer is about 1.1 mm thick.

6. The optical storage medium of claim 1, wherein said pattern of features includes a spiral groove.

7. The optical storage medium of claim 3, wherein said pattern of features includes a spiral groove.

8. An optical storage medium, comprising:

a first layer having a pattern of features in at least one major surface;

a reflective coating;

said reflective coating including a metal alloy, said metal alloy including silver and scandium, wherein the relationship between the amounts of silver and scandium in the metal alloy is defined by Ag_xSc_w where 0.9500<

x<

0.9999 and 0.0001<

w<

0.05, wherein said reflective coating is about 60 nanometers thick or less.

9. The optical storage medium of claim 8, wherein 0.001<

w<

0.03.

10. The optical storage medium of claim 8, wherein said reflective coating is about 40 nanometers thick or less.

11. The optical storage medium of claim 8, wherein said reflective coating is about 30 nanometers thick or less.

12. The optical storage medium of claim 8, wherein said first layer is about 1.1 mm thick.

13. The optical storage medium of claim 8, wherein said pattern of features includes a spiral groove.

14. The optical storage medium of claim 10, wherein said pattern of features includes a spiral groove.

15. An optical storage medium, comprising:

a first layer having a pattern of features in at least one major surface;

a reflective coating;

said reflective coating including a metal alloy, said metal alloy including silver and bismuth, wherein the relationship between the amounts of silver and bismuth in the metal alloy is defined by Ag_xBi_w where 0.9500<

x<

0.9999 and 0.0001<

w<

0.05, wherein said reflective coating is about 60 nanometers thick or less.

16. The optical storage medium of claim 15, wherein 0.001<

w<

0.03.

17. The optical storage medium of claim 15, wherein said reflective coating is about 40 nanometers thick or less.

18. The optical storage medium of claim 15, wherein said reflective coating is about 30 nanometers thick or less.

19. The optical storage medium of claim 15, wherein said first layer is about 1.1 mm thick.

20. The optical storage medium of claim 15, wherein said pattern of features includes a spiral groove.

21. The optical storage medium of claim 17, wherein said pattern of features includes a spiral groove.

22. An optical storage medium, comprising:

a first layer having a pattern of features in at least one major surface;

a reflective coating;

said reflective coating including a metal alloy, said metal alloy including silver, copper, and element A, where A is selected from the group of elements consisting of yttrium, scandium, or bismuth, wherein the relationship between the amounts of silver, copper, and element A in the metal alloy is defined by Ag_xCu_zA_w where 0.85<

x<

0.9998, 0.0001<

z<

0.10, and 0.0001<

w<

0.05, wherein said reflective coating is about 60 nanometers thick or less.

23. The optical storage medium of claim 22, wherein 0.001<

w<

0.03.

24. The optical storage medium of claim 22, wherein said reflective coating is about 40 nanometers thick or less.

25. The optical storage medium of claim 22, wherein said reflective coating is about 30 nanometers thick or less.

26. The optical storage medium of claim 22, wherein said first layer is about 1.1 mm thick.

27. The optical storage medium of claim 22, wherein said pattern of features includes a spiral groove.

28. The optical storage medium of claim 24, wherein said pattern of features includes a spiral groove.

29. An optical storage medium, comprising:

a first layer having a pattern of features in at least one major surface;

a reflective coating;

said reflective coating including a metal alloy, said metal alloy including silver, copper, and magnesium, wherein the relationship between the amounts of silver, copper, and magnesium in the metal alloy is defined by Ag_xCu_zMg_w where 0.85<

x<

0.9998, 0.0001<

z<

0.10, and 0.0001<

w<

0.05, wherein said reflective coating is about 60 nanometers thick or less.

30. The optical storage medium of claim 29, wherein 0.001<

w<

0.03.

31. The optical storage medium of claim 29, wherein said reflective coating is about 40 nanometers thick or less.

32. The optical storage medium of claim 29, wherein said reflective coating is about 30 nanometers thick or less.

33. The optical storage medium of claim 29, wherein said first layer is about 1.1 mm thick.

34. The optical storage medium of claim 29, wherein said pattern of features includes a spiral groove.

35. The optical storage medium of claim 31, wherein said pattern of features includes a spiral groove.

36. An optical storage medium, comprising:

a first layer having a pattern of features in at least one major surface;

a reflective coating;

said reflective coating including a metal alloy, said metal alloy including silver, copper, and cobalt, wherein the relationship between the amounts of silver, copper, and cobalt in the metal alloy is defined by Ag_xCu_zCo_w where 0.85<

x<

0.9998, 0.0001<

z<

0.10, and 0.0001<

w<

0.05, wherein said reflective coating is about 60 nanometers thick or less.

37. The optical storage medium of claim 36, wherein 0.001<

w<

0.03.

38. The optical storage medium of claim 36, wherein said reflective coating is about 40 nanometers thick or less.

39. The optical storage medium of claim 36, wherein said reflective coating is about 30 nanometers thick or less.

40. The optical storage medium of claim 36, wherein said first layer is about 1.1 mm thick.

41. The optical storage medium of claim 36, wherein said pattern of features includes a spiral groove.

42. The optical storage medium of claim 38, wherein said pattern of features includes a spiral groove.

43. An optical storage medium, comprising:

a first layer having a pattern of features in at least one major surface;

a reflective coating;

said reflective coating including a metal alloy, said metal alloy including silver, zinc, and magnesium, wherein the relationship between the amounts of silver, zinc, and magnesium in the metal alloy is defined by Ag_xZn_yMg_w where 0.8000<

x<

0.9998, 0.0001<

y<

0.15, and 0.0001<

w<

0.05, wherein said reflective coating is about 60 nanometers thick or less.

44. The optical storage medium of claim 43, wherein 0.001<

w<

0.03.

45. The optical storage medium of claim 43, wherein said reflective coating is about 40 nanometers thick or less.

46. The optical storage medium of claim 43, wherein said reflective coating is about 30 nanometers thick or less.

47. The optical storage medium of claim 43, wherein said first layer is about 1.1 mm thick.

48. The optical storage medium of claim 43, wherein said pattern of features includes a spiral groove.

49. The optical storage medium of claim 45, wherein said pattern of features includes a spiral groove.

50. An optical storage medium, comprising:

a first layer having a pattern of features in at least one major surface;

a reflective coating;

said reflective coating including a metal alloy, said metal alloy including silver, zinc, and cobalt, wherein the relationship between the amounts of silver, zinc, and cobalt in the metal alloy is defined by Ag_xZn_yCo_w where 0.8000<

x<

0.9998, 0.0001<

y<

0.15, and 0.0001<

w<

0.05, wherein said reflective coating is about 60 nanometers thick or less.

51. The optical storage medium of claim 50, wherein 0.001<

w<

0.03.

52. The optical storage medium of claim 50, wherein said reflective coating is about 40 nanometers thick or less.

53. The optical storage medium of claim 50, wherein said reflective coating is about 30 nanometers thick or less.

54. The optical storage medium of claim 50, wherein said first layer is about 1.1 mm thick.

55. The optical storage medium of claim 50, wherein said pattern of features includes a spiral groove.

56. The optical storage medium of claim 52, wherein said pattern of features includes a spiral groove.