Method to build robust mechanical structures on substrate surfaces
View Patent ↗A robust mechanical structure is provided to prevent small foundation structures formed on a substrate from detaching from the substrate surface. The strengthened structure is formed by plating a foundation metal layer on a seed layer and then embedding the plated foundation structure in an adhesive polymer material, such as epoxy. Components, such as spring probes, can then be constructed on the plated foundation. The adhesive polymer material better assures the adhesion of the metal foundation structure to the substrate surface by counteracting forces applied to an element, such as a spring probe, attached to the plated foundation.
1. A probe card comprising:
a substrate;
an electrical contact pad disposed on the substrate, the contact pad comprising an outer surface;
a reinforcing layer disposed on the substrate and directly on a peripheral portion of the outer surface of the contact pad, the reinforcing layer comprising an opening through the reinforcing layer to an inner portion of the outer surface of the electrical contact pad;
a conductive foundation disposed within the opening on the inner portion of the outer surface of the contact pad, wherein the conductive foundation is electrically coupled to the electrical contact pad, wherein the reinforcing layer surrounds and contacts sidewalls of the conductive foundation that extend substantially perpendicularly from the outer surface of the contact pad, the reinforcing layer thereby encasing the conductive foundation around the sidewalls; and
a spring probe disposed on an outer surface of the conductive foundation, wherein the sidewalls of the conductive foundation are substantially perpendicular to the outer surface of the conductive foundation.
2. The probe card of claim 1 , wherein the substrate is rigid.
3. The probe card of claim 1 , wherein the foundation is adhered to the reinforcing layer, and the reinforcing layer is adhered to the substrate.
4. The probe card of claim 1 , wherein the spring probe is partially encased in the reinforcing layer.
5. The probe card of claim 1 , where in the spring probe is attached to the foundation by any of: a wire bond, plated metal, solder, brazing material, and conductive adhesive.
6. The probe card of claim 1 , wherein the reinforcing layer covers the inner portion of the outer surface of the electrical contact pad.
7. The probe card of claim 1 , wherein the reinforcing layer comprises a polymer.
8. The probe card of claim 7 , wherein the reinforcing layer comprises a filled polymer.
9. The probe card of claim 1 , wherein the reinforcing layer comprises a non-adhesive material.
10. The probe card of claim 1 , wherein the reinforcing layer comprises an adhesive material.
11. The probe card of claim 1 , wherein the conductive foundation has a shape selected from the group of shapes consisting of: round, rectangular, cross-shaped, and sawtooth shaped.
12. The probe card of claim 1 , wherein the conductive foundation comprises anchor portions.
13. A probe card comprising:
a substrate;
an electrical contact pad disposed on a surface of the substrate, the contact pad comprising an outer surface that is substantially parallel to the surface of the substrate;
a reinforcing layer disposed on the surface of the substrate and directly on a peripheral portion of the outer surface of the electrical contact pad, the reinforcing layer comprising an opening through the reinforcing layer to an inner portion of the outer surface of the electrical contact pad;
a conductive foundation disposed within the opening on the inner portion of the outer surface of the contact pad, wherein the conductive foundation is electrically coupled to the electrical contact pad, wherein the reinforcing layer surrounds and contacts sidewalls of the conductive foundation that extend substantially perpendicularly from the outer surface of the contact pad, the reinforcing layer thereby encasing the conductive foundation around the sidewalls; and
a spring probe disposed on an outer surface of the conductive foundation, wherein the sidewalls of the conductive foundation are substantially perpendicular to the outer surface of the conductive foundation.
14. The probe card of claim 13 , wherein the spring probe is partially encased in the reinforcing layer.
15. The probe card of claim 13 , wherein the reinforcing layer comprises a polymer.
16. The probe card of claim 15 , wherein the reinforcing layer comprises a filled polymer.
17. The probe card of claim 13 , wherein the reinforcing layer comprises a non-adhesive material.
18. The probe card of claim 13 , wherein the conductive foundation has a shape selected from the group of shapes consisting of: round, rectangular, cross-shaped, and sawtooth shaped.
19. The probe card of claim 13 , wherein the conductive foundation comprises anchor portions.
20. The probe card of claim 13 , wherein the substrate is rigid.
21. The probe card of claim 1 , wherein the conductive foundation is disposed on the inner portion of the outer surface of the conductive pad but is not disposed on the peripheral portion of the outer surface of the conductive pad.
22. The probe card of claim 21 , wherein the peripheral portion of the outer surface of the conductive pad surrounds entirely the inner portion of the outer surface.