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

• US 6,007,889 A
• Filed: 06/22/1998
• Issued: 12/28/1999
• Est. Priority Date: 06/22/1998
• Status: Expired due to Term

• Current Assignee: Target Technology Company LLC
• Original Assignee: Target Technology Company LLC
• Inventors: Nee, Han H.
• Primary Examiner(s): MULVANEY, ELIZABETH EVANS
• Application Number:
  US09/102,163
• Time in Patent Office: 554 Days
• Field of Search: 428/64.1, 428/64.2, 428/64.4, 428/457, 428/913, 430/270.11, 430/495.1, 430/945, 369/283, 369/288
• US Class Current: 428/64.1
• CPC Class Codes: G11B 7/258 of reflective layers
• CPC Class Codes: G11B 7/259 based on silver
• CPC Class Codes: Y10S 428/913 Material designed to be responsive to temperature, light, moisture
• CPC Class Codes: Y10S 430/146 Laser beam
• CPC Class Codes: Y10T 428/21 Circular sheet or circular blank
• CPC Class Codes: Y10T 428/31678 Of metal

Abstract

A copper-based or silver-based alloy thin film is provided for the highly reflective or semi-reflective layer of optical discs. Alloy additions to silver include gold, palladium, copper, rhodium, ruthenium, osmium, iridium, and platinum. Alloy additions to copper include silver, cadmium, gold, magnesium, aluminum, and nickel. These alloys have moderate to high reflectivity and reasonable corrosion resistance in the ambient environment.

Claims

1. An optical storage medium, comprising:

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

a first reflective layer adjacent the feature pattern, the reflective layer including a metal alloy, said metal alloy including silver and gold wherein the relationship between the amounts of silver and gold is defined by Ag_x Au_y where 0.9<

x<

0.999 and 0.001≦

y≦

0.10.

2. The medium of claim 1, and wherein 0.05≦

y≦

0.095.

3. The medium of claim 1, and further including:

a second substrate having a pattern of features in at least one major surface;

a second reflective layer adjacent the feature pattern of said second substrate; and

a space layer, located between said first and second substrates.

4. The medium of claim 1, wherein said metal alloy includes a third metal that is copper, and wherein the relationship between the amounts of silver, gold, and copper is defined by Ag_x Au_y Cu_z where 0.0001<

z<

0.10.

5. The medium of claim 2, wherein said metal alloy includes a third metal that is copper, and wherein the relationship between the amounts of silver, gold, and copper is defined by Ag_x Au_y Cu_z where 0.0001<

z<

0.05.

6. The medium of claim 1, wherein said metal alloy includes a third metal that is rhodium, and wherein the relationship between the amounts of silver, gold, and rhodium is defined by Ag_x Au_y Rh_w where 0.0001<

w<

0.10.

7. The medium of claim 2, wherein said metal alloy includes a third metal that is rhodium, and wherein the relationship between the amounts of silver, gold, and rhodium is defined by Ag_x Au_y Rh_w where 0.0001<

w<

0.05.

8. The medium of claim 1, and wherein said metal alloy further comprises a precious metal selected from the group consisting of ruthenium, osmium, iridium, platinum, and mixtures thereof, and wherein said precious metal is present from about 0.01 a/o percent to about 5.0 a/o percent of the amount of silver present.

9. An optical storage medium, comprising:

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

a first reflective layer adjacent the feature pattern, the reflective layer including a metal alloy, said metal alloy including silver and palladium wherein the relationship between the amounts of silver and palladium is defined by Ag_x Pd_t where 0.85<

x<

0.999 and 0.001<

t<

0.15.

10. The medium of claim 9, and wherein 0.05≦

t≦

0.10.

11. The medium of claim 9, and further including:

a second substrate having a pattern of features in at least one major surface;

a second reflective layer adjacent the feature pattern of said second substrate; and

a space layer, located between said first and second substrates.

12. The medium of claim 9, wherein said metal alloy includes a third metal that is copper, and wherein the relationship between the amounts of silver, palladium, and copper is defined by Ag_x Pd_t Cu_z where 0.0001<

z<

0.10.

13. The medium of claim 10, wherein said metal alloy includes a third metal that is copper, and wherein the relationship between the amounts of silver, palladium, and copper is defined by Ag_x Pd_t Cu_z where 0.0001<

z<

0.05.

14. The medium of claim 9, wherein said metal alloy includes a third metal that is rhodium, and wherein the relationship between the amounts of silver, palladium, and rhodium is defined by Ag_x Pd_t Rh_w where 0.0001<

w<

0.10.

15. The medium of claim 10, wherein said metal alloy includes a third metal that is rhodium, and wherein the relationship between the amounts of silver, palladium, and rhodium is defined by Ag_x Pd_t Rh_w where 0.0001<

w<

0.05.

16. The medium of claim 9, and wherein said metal alloy further comprises a precious metal selected from the group consisting of ruthenium, osmium, iridium, platinum, and mixtures thereof, and wherein said precious metal is present from about 0.01 a/o percent to about 5.0 a/o percent of the amount of silver present.

17. An optical storage medium, comprising:

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

a first reflective layer adjacent the feature pattern, the reflective layer including a metal alloy, said metal alloy including silver, gold, and palladium wherein the relationship between the amounts of silver, gold, and palladium is defined by Ag_x Au_y Pd_t where 0.75<

x<

0.998, 0.001 <

y <

0.10, and 0.001 <

t <

0.15.

18. The medium of claim 17, and wherein 0.05≦

y≦

0.095 and 0.04≦

t≦

0.11.

19. The medium of claim 17, and further including:

a second substrate having a pattern of features in at least one major surface;

a second reflective layer adjacent the feature pattern of said second substrate; and

a space layer, located between said first and second substrates.

20. The medium of claim 17, wherein said metal alloy includes a third metal that is copper, and wherein the relationship between the amounts of silver, gold, palladium, and copper is defined by Ag_x Au_y Pd_t Cu_z where 0.0001<

z<

0.10.

21. The medium of claim 18, wherein said metal alloy includes a third metal that is copper, and wherein the relationship between the amounts of silver, gold, palladium, and copper is defined by Ag_x Au_y Pd_t Cu_z where 0.0001<

z<

0.05.

22. The medium of claim 17, wherein said metal alloy includes a third metal that is rhodium, wherein the relationship between the amounts of silver, gold, palladium, and rhodium is defined by Ag_x Au_y Pd_t Rh_w where 0.0001<

w<

0.10.

23. The medium of claim 18, wherein said metal alloy includes a third metal that is rhodium, wherein the relationship between the amounts of silver, gold, palladium, and rhodium is defined by Ag_x Au_y Pd_t Rh_w where 0.0001<

w<

0.05.

24. The medium of claim 17, and wherein said metal alloy further comprises a precious metal selected from the group consisting of ruthenium, osmium, iridium, platinum, and mixtures thereof, and wherein said precious metal is present from about 0.01 a/o percent to about 5.0 a/o percent of the amount of silver present.

25. An optical storage medium, comprising:

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

a first reflective layer adjacent the feature pattern, the reflective layer including a metal alloy, said metal alloy including copper and silver wherein the relationship between the amounts of copper and silver is defined by Cu_m Ag_n where 0.95<

m<

0.9999 and 0.0001<

n<

0.05, and wherein said metal alloy includes the metals cadmium, magnesium, aluminum, and nickel, and where the amount of silver, cadmium, magnesium, aluminum, and nickel is no more than 6 atomic percent, and where the amount of copper is no less than 94 atomic percent.

26. The medium of claim 25, where silver is present at a level of 0.2 atomic percent, where cadmium is present at a level of 0.3 atomic percent, where magnesium is present at a level of 1.0 atomic percent, where aluminum is present at a level of 1.2 atomic percent, and where nickel is present at a level of 0.8 atomic percent.

27. An optical storage medium, comprising:

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

a first reflective layer adjacent the feature pattern, the reflective layer including a metal alloy, said metal alloy including copper and cadmium wherein the relationship between the amounts of copper and cadmium is defined by Cu_m Cd_o where 0.85<

m<

0.9999 and 0.0001<

o<

0.15.

28. An optical storage medium, comprising:

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

a first reflective layer adjacent the feature pattern, the reflective layer including a metal alloy, said metal alloy including copper and gold wherein the relationship between the amounts of copper and gold is defined by Cu_m Au_p where 0.7<

m<

0.9999 and 0.0001<

p<

0.30.

29. An optical storage medium, comprising:

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

a first reflective layer adjacent the feature pattern, the reflective layer including a metal alloy, said metal alloy including copper and magnesium wherein the relationship between the amounts of copper and magnesium is defined by Cu_m Mg_q where 0.9<

m<

0.9999 and 0.0001<

q<

0.10.

30. An optical storage medium, comprising:

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

a first reflective layer adjacent the feature pattern, the reflective layer including a metal alloy, said metal alloy including copper and nickel wherein the relationship between the amounts of copper and nickel is defined by Cu_m Ni_s where 0.87<

m<

0.9999 and 0.0001<

s<

0.13.