Sputter-coating target and method of use

• US 5,403,458 A
• Filed: 08/05/1993
• Issued: 04/04/1995
• Est. Priority Date: 08/05/1993
• Status: Expired due to Fees

• Current Assignee: Guardian Glass LLC (KOCH Industries Incorporated)
• Original Assignee: Guardian Industries Corporation (KOCH Industries Incorporated)
• Inventors: Lingle, Philip J., Hartig, Klaus W.
• Primary Examiner(s): Breneman, R. Bruce
• Assistant Examiner(s): MCDONALD, RODNEY GLENN
• Application Number:
  US08/102,585
• Time in Patent Office: 607 Days
• Field of Search: 204/298.12, 204/298.13, 204/192.15, 204/192.16, 204/192.17, 204/192.18, 204/192.21, 204/192.22, 204/192.23, 204/192.25 , 204/192.26, 204/192.27, 204/192.28, 204/192.29, 204/298.06, 204/298.14, 204/298.21, 204/298.22
• US Class Current: 204/192.15
• CPC Class Codes: C23C 14/3414 Metallurgical or chemical aspects of target preparation, e.g. casting, powder metallurgy
• CPC Class Codes: C23C 14/564 Means for minimising impurities in the coating chamber such as dust, moisture, residual gases
• CPC Class Codes: H01J 37/3426 Material
• CPC Class Codes: H01J 37/3438 Electrodes other than cathode

Abstract

A sputter coating target which alleviates the need for anode reconditioning due to a buildup of a nonconductive coating comprises a coating component which itself or its reactive product is substantially electrically nonconductive and a dopant component which itself or its reactive product is substantially electrically conductive.

Claims

1. In an apparatus for sputter-coating a layer coating comprised of a metal or a reaction product thereof onto a substrate, said coating being required to meet certain physical characteristics determined prior to sputter-coating, said apparatus including a depletable cathode target system and an anode, said anode being so located such that said layer coating is deposited onto both said substrate and said anode during said sputter-coating, said cathode target system being comprised of a metal coating component and said metal coating component being of such a nature that said coating layer formed therefrom or a reaction product thereof will be sufficiently electrically non-conductive to render said anode inoperative at a time significantly prior to said cathode target system becoming operatively depleted, the improvement comprising wherein said cathode target system is further comprised of a dopant component which by itself or its reactive product, after being sputter-coated onto said anode, is substantially electrically conductive and is in an amount sufficient and so located such that the resulting layer coating formed on said anode is sufficiently electrically conductive so as to maintain said anode operative until said time said cathode target system becomes substantially operatively depleted and wherein said resulting layer coating formed on said substrate meets the said certain physical characteristics determined prior to sputter-coating.

2. An apparatus according to claim 1, wherein said layer coating on said anode has a resistivity of at least about 1 megohm per square until said cathode target system is substantially operatively depleted.

3. The apparatus of claim 2 wherein said dopant component is in an amount less than the amount of said coating component.

4. The apparatus of claim 3 wherein said target includes about 0.1%-20% by weight of said dopant component, the remainder being substantially all coating component.

5. The apparatus of claim 4 wherein said target consists essentially of by weight about 95% coating component and about 5% by weight dopant component.

6. The apparatus of claim 5 wherein said coating component is selected from the group consisting of silicon, aluminum, boron, bismuth, germanium, vanadium, tin, zinc, titanium, zirconium, chromium and tungsten.

7. The apparatus of claim 6 wherein said dopant component is selected from the group consisting of silver, gold, platinum and mixtures thereof.

8. The apparatus of claim 6 wherein said dopant component is a oxidation resistant metal.

9. The apparatus of claim 8 wherein said dopant component is selected from the group consisting of nickel, palladium and mixtures thereof.

10. The apparatus of claim 6 wherein said dopant component is one whose oxides are substantially electrically conductive.

11. The apparatus of claim 10 wherein said dopant component is selected from the group consisting of indium, tin and mixtures thereof.

12. The apparatus of claim 6 wherein said dopant component is one whose nitrides are substantially electrically conductive.

13. The apparatus of claim 12 wherein said dopant component is selected from the group consisting of chromium, hafnium, titanium, zirconium and mixtures thereof.

14. The apparatus of claim 2 wherein said coating and dopant components are combined in a uniform mixture.

15. The apparatus of claim 2 wherein said coating and dopant components are separate, contiguously attached elements of said target.

16. The apparatus of claim 15 wherein said dopant component and said coating component of said target are so located with respect to each other, said anode and said substrate to be coated so as to minimize the amount of dopant component sputtered onto said substrate and maximize the amount of said dopant component sputtered onto said anode while maximizing the amount of said coating component sputtered onto said substrate while minimizing the amount of said coating component sputtered onto said anode.

17. In a method for sputter-coating a layer coating comprised of a metal or a reaction product thereof onto a substrate, said coating being required to meet certain physical characteristics determined prior to sputter-coating, said method including:

providing a depletable cathode target system which includes a metal coating component, said metal coating component being of such a nature that said coating layer formed therefrom or a reaction product thereof will be sufficiently electrically non-conductive to render said anode inoperative at a time significantly prior to said cathode target system becoming operatively depleted;

providing an anode;

locating said anode in a position such that said layer coating will be deposited onto both said substrate and said anode during ;

said sputter-coating and sputter-coating said layer coating onto said substrate and said anode, the improvement comprising;

including in said cathode target system a dopant component which by itself or its reaction product, after being sputter-coated onto said anode, is substantially sufficient and so located such that the resulting layer coating formed on said anode is sufficiently electrically conductive so as to maintain said anode operative until said time said cathode target system becomes substantially operatively depleted and wherein said resulting layer coating formed on said substrate meets the said certain physical characteristics determined prior to sputter-coating; and

sputter-coating said dopant component as well as said metal coating component onto said substrate and said anode whereby the resulting layer coating formed on said substrate meets the said certain physical characteristics determined prior to said sputter-coating and the resulting coating on said anode remains operatively electrically conductive until said cathode target system is substantially operatively depleted.

18. A method according to claim 17, wherein the resulting coating on said anode maintains a resistivity of at least about 1 megohm per square until said cathode target system is substantially operatively depleted.

19. The method of claim 18 further comprising the step of:

providing a source of a reactive gas thereby producing a coating which is the reactive product of the coating and dopant components.

20. A method according to claim 19 wherein said target includes about 0.1%-20% by weight of said dopant component, the remainder being substantially all coating component.

21. A method according to claim 20 wherein said target consists essentially by weight of about 95% coating component and about 5% by weight dopant component.

22. A method according to claim 20 wherein said coating component is silicon and said dopant component is titanium.

23. A method according to claim 22 wherein said dopant and coating component are in the form of a substantially homogeneous mixture thereof.