Claims
- 1. A copper foil for lamination to a dielectric substrate, the copper foil comprising:
a peel strength enhancement coating deposited on a surface of the copper foil, the peel strength enhancement coating consisting essentially of a metal and metal oxide mixture, the metal and metal oxide mixture being formed from one or more of: vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, technetium, and rhenium.
- 2. The copper foil of claim 1, wherein the surface of the copper foil is smooth.
- 3. The copper foil of claim 1, wherein the metal oxide is selected from elements of chromium, tungsten, and molybdenum.
- 4. The copper foil of claim 1, wherein the peel strength enhancement coating has a thickness of between about 20 to about 200 angstroms.
- 5. The copper foil of claim 1, wherein silane is deposited on the peel strength enhancement coating prior to lamination to the dielectric substrate.
- 6. An article comprising:
a dielectric substrate; a copper foil having a smooth surface laminated to the dielectric substrate; and a peel strength enhancement coating disposed between the copper foil and the dielectric substrate, wherein the copper foil exhibits less than or equal to 10% loss of peel strength when measured in accordance with IPC-TM-650 Method 2.4.8.5 using a ⅛ inch test specimen after being immersed in 4N HCl at 60° C. for 6 hours.
- 7. The article of claim 6, wherein the peel strength enhancement coating consists essentially of a metal and metal oxide mixture formed from one or more of: vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, technetium, and rhenium.
- 8. The article of claim 7, wherein the metal oxide is selected from elements of chromium, tungsten, and molybdenem.
- 9. The article of claim 6, wherein the peel strength enhancement coating has a thickness of between about 20 to about 200 angstroms.
- 10. The article of claim 6, wherein the peel strength enhancement coating exhibits less than or equal to 10% edge undercut after the immersion in 4N HCl at 60° C. for 6 hours.
- 11. The article of claim 6, wherein the copper foil exhibits less than or equal to about 7% loss of peel strength when measured in accordance with 1 PC-TM-650 Method 2.4.8.5 using a ⅛ inch test specimen after being immersed in 4N HCl at 60° C. for 6 hours.
- 12. The article of claim 6, wherein silane is deposited on the peel strength enhancement coating prior to lamination to the dielectric substrate.
- 13. A method for increasing the peel strength of a copper foil laminated to a dielectric substrate, the method comprising:
prior to lamination, immersing the copper foil in an aqueous electrolytic solution containing oxyanions formed from one or more of: vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, technetium, and rhenium.
- 14. The method of claim 13, wherein the metal is selected from one of chromium, molybdenum, and tungsten.
- 15. The method of claim 13, wherein the aqueous electrolytic solution contains chromate, tungstate, or molybdate ions in deionized water.
- 16. The method of claim 13 wherein the aqueous solution is an electrolyte solution in an electrolytic cell, and the method further comprises:
passing current through the copper foil and the electrolyte solution such that a coating having a thickness of between about 20 to about 200 angstroms is deposited on the copper foil.
- 17. The method of claim 16, further comprising:
immersing the copper foil in silane after depositing the coating on the copper foil.
- 18. A copper foil for lamination to a dielectric substrate, the copper foil comprising:
a layer deposited on a surface of the copper foil, the layer being formed from chromium and zinc ions or oxides and treated with an aqueous solution containing at least 0.5% silane.
- 19. The copper foil of claim 18, wherein the surface of the copper foil is smooth.
- 20. The copper foil of claim 18, wherein the thickness of the layer is from about 10 angstroms to about 100 angstroms.
- 21. A method for increasing the peel strength of a copper foil laminated to a dielectric substrate, the method comprising:
prior to lamination, co-depositing a mixture of chromium and zinc ions or oxides on surfaces of the copper foil; subsequent to the co-deposition step, immersing the copper foil for at least one second in an aqueous solution containing at least 0.5% silane in deionized water; and drying the copper foil prior to lamination.
- 22. The method of claim 21, wherein the aqueous solution consists essentially of 0.5% silane in deionized water.
- 23. The method of claim 21, wherein the aqueous solution is at a temperature of between about 15° C. to about 30° C.
- 24. The method of claim 21, wherein the co-depositing a mixture of chromium and zinc ions or oxides includes:
providing an electrolytic cell containing an anode disposed in an electrolyte solution containing chromium and zinc ions; providing the copper foil as a cathode; and electrolytically depositing the chromium and zinc ions on the copper foil.
- 25. The method of claim 24, wherein the electrolyte solution is a basic solution containing hydroxide ions from about 0.07 g/l to about 7 g/l zinc ions, and from about 0.1 g/l to about 100 g/l of a water soluble hexavalent chromium salt wherein the concentration of either the zinc ions or the chromium (VI) ions or both is less than 1.0, and the co-deposition step includes:
immersing the copper foil in the electrolyte solution; and passing current through the copper foil and the electrolyte solution such that a current density of from about 1 milliamp per square centimeter to about 1 amp per square centimeter is provided.
- 26. The method of claim 25, wherein the electrolyte solution consists essentially of from about 10 to about 35 g/l NaOH, from about 0.2 to about 1.5 g/l ZnO, and from about 0.2 to about 2 g/l Na2Cr2O7.2H2O.
- 27. The method of claim 21, wherein the thickness of a layer formed from the chromium and zinc ions or oxides deposited on the copper foil is from about 10 angstroms to about 100 angstroms.
- 28. The method of claim 21, further comprising:
rinsing the copper foil after the immersing and before the drying.
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional Patent Application No. 60/431,013, filed on Dec. 5, 2002, which is incorporated by reference herein in its entirety.
Provisional Applications (1)
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Number |
Date |
Country |
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60431013 |
Dec 2002 |
US |