Methods of forming electronic structures including conductive shunt layers and related structures
Methods of forming an electronic structure may include forming a seed layer on an electronic substrate, and forming a conductive shunt layer on portions of the seed layer wherein portions of the seed layer are free of the conductive shunt layer. A conductive barrier layer may be formed on the conductive shunt layer opposite the seed layer wherein the conductive shunt layer comprises a first material and wherein the barrier layer comprises a second material different than the first material. Moreover, a solder layer may be formed on the barrier layer opposite the conductive shunt layer wherein the solder layer comprises a third material different than the first and second materials. Related structures are also discussed.
1. A method for forming an electronic structure comprising:
forming a conductive pad on a substrate;
forming an insulating layer on the substrate and on the conductive pad, the insulating layer having a via therein so that a portion of the conductive pad opposite the substrate is free of the insulating layer;
forming a primary conductive trace on the substrate so that the primary conductive trace is between the substrate and the insulating layer;
forming an electrical coupling between the primary conductive trace and the conductive pad, the electrical coupling providing at least two separate current flow paths between the primary conductive trace and the conductive pad;
forming a seed layer on the electronic substrate, wherein the seed layer is on the insulating layer, on sidewalls of the via, and on the portions of the conductive pad free of the insulating layer;
forming a conductive shunt layer on portions of the seed layer, wherein the conductive shunt layer is on the seed layer opposite the portions of the conductive pad free of the insulating layer, opposite the sidewalls of the via, and opposite portions of the insulating layer adjacent the via, wherein portions of the seed layer are free of the conductive shunt layer, and wherein the conductive shunt layer comprises a first material; and
forming a solder layer on the conductive shunt layer wherein the solder layer comprises a second material different than the first material.
2. A method according to claim 1 further comprising:
after forming the solder layer, removing portions of the seed layer free of the solder layer.
3. A method according to claim 1 wherein the conductive shunt layer comprises copper.
4. A method according to claim 1 wherein the conductive shunt layer comprises a metal layer having a thickness of at least approximately 0.5 μm.
5. A method according to claim 4 further comprising:
heating the solder layer above its melting temperature while maintaining the conductive shunt layer having the thickness of at least approximately 0.5 μm; and
after heating the solder layer, cooling the solder layer below its melting temperature while maintaining the conductive shunt layer having the thickness of at least approximately 0.5 μm after cooling the solder layer below its melting temperature.
6. A method according to claim 4 wherein the conductive shunt layer comprises a metal layer having a thickness of at least approximately 1.0 μm.
7. A method according to claim 6 wherein the conductive shunt layer comprises a metal layer having a thickness in the range of approximately 1.0 μm to 5.0 μm.
8. A method according to claim 1 further comprising:
before forming the solder layer, forming a conductive barrier layer on the conductive shunt layer opposite the seed layer
wherein the barrier layer comprises a third material different than the first and second materials.
9. A method according to claim 8 wherein the barrier layer comprises at least one of nickel, platinum, palladium and/or combinations thereof.
10. A method according to claim 1 wherein the seed layer comprises an adhesion layer of a third material different than the first material of the conductive shunt layer.
11. A method according to claim 10 wherein the adhesion layer comprises titanium, tungsten, chrome, and/or combinations thereof.
12. A method according to claim 10 wherein the seed layer comprises a plating conduction layer on the adhesion layer opposite the substrate, wherein the plating conduction layer comprises the first material of the conductive shunt layer.
13. A method according to claim 1 further comprising:
after forming the seed layer, forming a mask layer on the seed layer, the mask layer having a pattern exposing a surface portion of the seed layer;
wherein forming the conductive shunt layer comprises plating the conductive shunt layer on the exposed surface portion of the seed layer; and
wherein forming the solder layer comprises plating the solder layer on the conductive shunt layer.
14. A method according to claim 1 , wherein the conductive shunt layer extends on a surface of the insulating layer outside the via therein.
15. A method for forming an electronic structure comprising:
forming a conductive pad on a substrate;
forming an insulating layer on the substrate and on the conductive pad, the insulating layer having a via therein so that a portion of the conductive pad opposite the substrate is free of the insulating layer;
forming a primary conductive trace on the substrate so that the primary conductive trace is between the substrate and the insulating layer;
forming an electrical coupling between the primary conductive trace and the conductive pad, the electrical coupling providing at least two separate current flow paths between the primary conductive trace and the conductive pad, wherein the electrical coupling is between the substrate and the insulating layer, and wherein the electrical coupling includes at least one perforation therein that provides the at least two separate current flow paths;
forming a seed layer on the substrate, wherein the seed layer is on the insulating layer, on sidewalls of the via, and on the portions of the conductive pad free of the insulating layer;
forming a conductive shunt layer on portions of the seed layer, wherein the conductive shunt layer is on the seed layer opposite the portions of the conductive pad free of the insulating layer, opposite the sidewalls of the via, and opposite portions of the insulating layer adjacent the via, wherein portions of the seed layer are free of the conductive shunt layer, and wherein the conductive shunt layer comprises a first material; and
forming a solder layer on the conductive shunt layer, wherein the solder layer comprises a second material different than the first material.
16. A method according to claim 15 further comprising:
after forming the solder layer, removing portions of the seed layer free of the solder layer.
17. A method according to claim 15 wherein the conductive shunt layer comprises copper.
18. A method according to claim 15 wherein the conductive shunt layer comprises a metal layer having a thickness of at least approximately 0.5 μm.
19. A method according to claim 15 wherein the seed layer comprises an adhesion layer of a third material different than the first material of the conductive shunt layer and a plating conduction layer on the adhesion layer opposite the substrate, wherein the plating conduction layer comprises the first material of the conductive shunt layer.
20. A method according to claim 15 further comprising:
after forming the seed layer, forming a mask layer on the seed layer, the mask layer having a pattern exposing a surface portion of the seed layer;
wherein forming the conductive shunt layer comprises plating the conductive shunt layer on the exposed surface portion of the seed layer; and
wherein forming the solder layer comprises plating the solder layer on the conductive shunt layer.