Methods of forming bumps using barrier layers as etch masks

1. A method of forming an electronic structure, the method comprising:

forming a seed layer on a substrate;

forming a mask on the seed layer, the mask including an aperture therein exposing a portion of the seed layer;

forming a barrier layer on the exposed portion of the seed layer;

forming a bump metal on the barrier layer;

removing the mask; and

selectively removing portions of the seed layer using the barrier layer as an etch mask;

wherein forming the bump metal is subsequent to selectively removing portions of the seed layer using the barrier layer as an etch mask.

2. A method according to claim 1 wherein forming the bump metal comprises placing a solid solder preform on the barrier layer.

3. A method according to claim 1 further comprising:

before forming the bump metal on the barrier layer, forming an oxidation barrier on the barrier layer wherein the oxidation barrier and the barrier layer comprise different materials.

4. A method according to claim 1 wherein selectively removing portions of the seed layer comprises etching portions of the seed layer exposed by the barrier layer using an etch chemistry that etches the seed layer selectively with respect to the barrier layer.

5. A method according to claim 1 wherein the barrier layer comprises a material different than the seed layer and different than the bump metal.

6. A method according to claim 5 wherein the seed layer comprises an adhesion layer on the substrate and a conductivity layer on the adhesion layer so that the adhesion layer is between the conductivity layer and the substrate.

7. A method according to claim 6 wherein the adhesion layer comprises at least one of titanium, tantalum, tungsten, chromium, aluminum, copper, iridium, platinum, and/or alloys thereof, and/or nitrides thereof.

8. A method according to claim 6 wherein the conductivity layer comprises at least one of aluminum, copper, nickel, gold, silver, and/or alloys thereof.

9. A method according to claim 5 wherein the barrier layer comprises at least one of nickel, cobalt, platinum, silver, palladium, gold, and/or alloys thereof.

10. A method according to claim 9 wherein the barrier layer comprises a layer of nickel-vanadium.

11. A method according to claim 5 wherein the bump metal comprises at least one of antimony, silver, bismuth, tin, lead, copper, silver, gold, nickel, zinc, and/or alloys thereof.

12. A method of forming an electronic structure, the method comprising:

forming a seed layer on a substrate;

selectively forming a barrier layer on a portion of the seed layer wherein the barrier layer and the seed layer comprise different materials and wherein the barrier layer comprises at least one of nickel, cobalt, platinum, silver, palladium, gold, and/or alloys thereof

selectively removing portions of the seed layer using the barrier layer as an etching mask; and

after selectively removing portions of the seed layer, providing a bump metal on the barrier layer opposite the seed layer wherein the bump metal and the barrier layer comprise different materials.

13. A method according to claim 12 wherein providing the bump metal comprises placing a solid solder preform on the barrier layer after selectively removing portions of the seed layer.

14. A method according to claim 13 further comprising:

before providing the bump metal, forming an oxidation barrier on the barrier layer wherein the oxidation barrier comprises a material different than a material of the barrier layer.

15. A method according to claim 12 wherein selectively removing portions of the seed layer comprises etching portions of the seed layer exposed by the barrier layer using an etch chemistry that etches the seed layer selectively with respect to the barrier layer.