Electrical barrier layers

Patent metadata

Field	Value
Publication number	US-9125333-B2
Application number	US-201113183870-A
Country	US
Kind code	B2
Filing date	Jul 15, 2011
Priority date	Jul 15, 2011
Publication date	Sep 1, 2015
Grant date	Sep 1, 2015

Abstract

Barrier layers for use in electrical applications. In some embodiments the barrier layer is a laminated barrier layer. In some embodiments the barrier layer includes a graded barrier layer.

First claim

What is claimed is:

1. A conductive pad adapted to create an electrical connection, comprising:
a conductive substrate having a surface;
a variable-composition nickel alloy layer disposed above the conductive substrate and having a thickness of no more than 800 nm in a direction extending away from the surface; and
a conductive layer disposed above the variable-composition nickel alloy layer,
wherein the variable-composition nickel alloy layer has a variable nickel concentration which varies within the nickel alloy layer in the direction of the thickness,
wherein the variable-composition nickel alloy layer comprises a minor constituent selected from the group consisting of boron, carbon, phosphorus, and tungsten,
wherein the concentration of the minor constituent adjacent the surface is at least 1 percent by weight, and
wherein the concentration of the minor constituent adjacent the conductive layer is at least 1 percent by weight;
wherein at least over a portion of the surface, the concentration of the minor constituent varies in the direction of the thickness throughout the variable-composition nickel alloy layer;
wherein at least over said portion of the surface, the variable-composition nickel alloy layer has a variable boron concentration within the nickel alloy layer;
wherein the boron concentration varies between about 0% and about 5% by weight within the nickel alloy layer;
wherein the variable composition nickel-alloy layer has first and second surfaces, the first surface being closer to the substrate than the second surface, and wherein the concentration of boron is higher at the first surface than the boron concentration at the second surface.

2. A conductive pad adapted to create an electrical connection, comprising:
a conductive substrate having a surface;
a variable-composition nickel alloy layer disposed above the conductive substrate and having a thickness of no more than 800 nm in a direction extending away from the surface; and
a conductive layer disposed above the variable-composition nickel alloy layer,
wherein the variable-composition nickel alloy layer has a variable nickel concentration which varies within the nickel alloy layer in the direction of the thickness,
wherein the variable-composition nickel alloy layer comprises a minor constituent selected from the group consisting of boron, carbon, phosphorus, and tungsten,
wherein the concentration of the minor constituent adjacent the surface is at least 1 percent by weight, and
wherein the concentration of the minor constituent adjacent the conductive layer is at least 1 percent by weight,
wherein the concentration of the minor constituent in the variable-composition nickel alloy layer varies linearly throughout the variable-composition nickel alloy layer.

3. A conductive pad adapted to create an electrical connection, comprising:
a conductive substrate having a surface;
a variable-composition nickel alloy layer disposed above the conductive substrate and having a thickness of no more than 800 nm in a direction extending away from the surface; and
a conductive layer disposed above the variable-composition nickel alloy layer,
wherein the variable-composition nickel alloy layer has a variable nickel concentration which varies within the nickel alloy layer in the direction of the thickness,
wherein the variable-composition nickel alloy layer comprises a minor constituent selected from the group consisting of boron, carbon, and tungsten,
wherein the concentration of the minor constituent adjacent the surface is at least 1 percent by weight, and
wherein the concentration of the minor constituent adjacent the conductive layer is at least 1 percent by weight;
wherein at least over a portion of the surface, the concentration of the minor constituent varies in the direction of the thickness throughout the variable-composition nickel alloy layer;
wherein at least over said portion of the surface, the concentration of the minor constituent decreases in the upward direction throughout the variable-composition nickel alloy layer.

4. The conductive pad of claim 3 wherein the minor constituent is boron.

5. The conductive pad of claim 4 wherein the boron concentration varies between about 0% and about 5% by weight within the nickel alloy layer.

6. The conductive pad of claim 3 wherein at least over said portion of the surface, the concentration of the minor constituent in the variable-composition nickel alloy layer varies non-linearly throughout the variable-composition nickel alloy layer.

7. The conductive pad of claim 3 wherein the minor constituent is carbon.

8. The conductive pad of claim 7 wherein the carbon concentration varies between about 0% and about 5% by weight within the variable-composition nickel alloy layer.

9. The conductive pad of claim 3 further comprising a nickel layer disposed on the conductive substrate, wherein the variable-composition nickel alloy layer is disposed on the nickel layer.

10. The conductive pad of claim 9 wherein the conductive layer is disposed on the variable-composition nickel alloy layer.

11. The conductive pad of claim 9 further comprising a second nickel layer disposed on the variable-composition nickel alloy layer, wherein the conductive layer is disposed on the second nickel layer.

12. The conductive pad of claim 11 wherein the combined depth of the nickel layer, variable-composition nickel alloy layer, and second nickel layer is between about 0.01 and 1.5 microns.

13. The conductive pad of claim 9 wherein the nickel layer has a thickness of between about 5 nm and about 50 nm.

14. The conductive pad of claim 3 further comprising a nickel layer disposed on the variable-composition nickel alloy layer.

15. The conductive pad of claim 14 wherein the variable-composition nickel alloy layer is disposed on the conductive substrate.

16. The conductive pad of claim 15 wherein the conductive layer is disposed on the nickel layer.

17. The conductive pad of claim 14 further comprising a second variable-composition nickel alloy layer disposed on the nickel layer.

18. The conductive pad of claim 17 wherein the combined thickness of the variable-composition nickel alloy layer, nickel layer, and second variable-composition nickel alloy layer is between about 0.01 and about 1.5 microns.

19. The conductive pad of claim 14 wherein the variable-composition nickel alloy layer is disposed on the conductive substrate.

20. The conductive pad of claim 17 wherein the conductive layer is disposed on the second variable-composition nickel alloy layer.

21. The conductive pad of claim 14 wherein the nickel layer has a depth of between about 5 nm and 50 nm.

22. The conductive pad of claim 3 wherein the conductive layer is a solder material.

23. A conductive pad adapted to create an electrical connection, comprising:
a conductive substrate having a surface; and
a solderable structure comprising:
a variable-composition nickel alloy layer disposed above the conductive substrate and having a thickness of no more than 800 nm in a direction extending away from the surface; and
a solderable conductive layer disposed above the variable-composition nickel alloy layer,
wherein the variable-composition nickel alloy layer has a variable nickel concentration which varies within the nickel alloy layer in the direction of the thickness,
wherein the variable-composition nickel alloy layer comprises a minor constituent selected from the grou

Assignees

• Uzoh Cyprian
• Oganesian Vage
• Mohammed Ilyas
• Haba Belgacem
• Savalia Piyush
• Mitchell Craig
• Tessera Inc

Inventors

• Uzoh Cyprian
• Oganesian Vage
• Mohammed Ilyas
• Haba Belgacem
• Savalia Piyush
• Mitchell Craig

Classifications

• H10W72/952

  comprising metals or metalloids, e.g. PbSn, Ag or Cu · CPC title

• H10W72/923

  Bond pads having multiple stacked layers · CPC title

• H10W72/59

  Bond pads specially adapted therefor · CPC title

• H05K1/09 Primary

  Use of materials for the {conductive, e.g. } metallic pattern · CPC title

• H05K3/4007 Primary

  Surface contacts, e.g. bumps (H05K3/4092 takes precedence; deposition of finish layers on pads H05K3/24; forming solder bumps H05K3/3465) · CPC title