Methods of fluxless micro-piercing of solder balls, and resulting devices
A method of establishing conductive connections is disclosed. The method includes providing an integrated circuit die having a plurality of solder balls each of which has an oxide layer on an outer surface of the solder ball. The method also includes performing a heating process to heat at least the solder balls and applying a force causing each of a plurality of piercing bond structures on a substrate to pierce one of the solder balls and its associated oxide layer to thereby establish a conductive connection between the solder ball and the piercing bond structure.
1. A device comprising:
a substrate having a first side and a second side facing away from the first side;
a plurality of piercing bond structures at the first side of the substrate, each of the piercing bond structures having an outer surface that surrounds a solid core of conductive material, wherein the outer surface includes an anti-oxidation material;
a plurality of contact pads at the second side of the substrate; and
a plurality of wiring traces electrically coupling the piercing bond structures with the contact pads,
wherein the anti-oxidation material is a first anti-oxidation material, the device further including a second anti-oxidation material over the first anti-oxidation material,
wherein the first anti-oxidation material is gold and the second anti-oxidation material is nickel, and
wherein individual piercing bond structures have a first end facing the first side of the substrate and a second end facing away from the first end, and wherein the second ends are non-flat.
2. The device of claim 1 , further comprising a standoff structure at the first side of the substrate, wherein the standoff structure extends away from the first side of the substrate for a distance.
3. The device of claim 1 , further comprising a non-conductive paste at the first side of the substrate.
4. The device of claim 1 , wherein the substrate includes a via extending from the first side of the substrate to the second side of the substrate, wherein at least one wiring trace lines the via.
5. A device comprising:
a substrate having a first side and a second side facing away from the first side;
a plurality of piercing bond structures at the first side of the substrate, each of the piercing bond structures having an outer surface that surrounds a solid core of conductive material, wherein the outer surface includes an anti-oxidation material;
a plurality of contact pads at the second side of the substrate; and
a plurality of wiring traces electrically coupling the piercing bond structures with the contact pads,
wherein the anti-oxidation material is a first anti-oxidation material, the device further including a second anti-oxidation material over the first anti-oxidation material,
wherein the first anti-oxidation material is gold and the second anti-oxidation material is nickel, and
wherein the piercing bond structures have substantially triangular cross-sections.
6. The device of claim 5 , further comprising a standoff structure at the first side of the substrate, wherein the standoff structure extends away from the first side of the substrate for a distance.
7. The device of claim 5 , further comprising a non-conductive paste at the first side of the substrate.
8. The device of claim 5 , wherein the substrate includes a via extending from the first side of the substrate to the second side of the substrate, wherein at least one wiring trace lines the via.
9. A device comprising:
a substrate having a first side and a second side facing away from the first side;
a plurality of piercing bond structures at the first side of the substrate, each of the piercing bond structures having an outer surface that surrounds a solid core of conductive material, wherein the outer surface includes an anti-oxidation material;
a plurality of contact pads at the second side of the substrate; and
a plurality of wiring traces electrically coupling the piercing bond structures with the contact pads,
wherein the anti-oxidation material is a first anti-oxidation material, the device further including a second anti-oxidation material over the first anti-oxidation material,
wherein the first anti-oxidation material is gold and the second anti-oxidation material is nickel, and
wherein individual piercing bond structures have a first end facing the first side of the substrate and a second end facing away from the first end, and wherein the individual second ends have cross-sections selected from a group consisting of a pointed cross-section, a rounded cross-section, and a multiple-peak cross section.
10. The device of claim 9 , further comprising a standoff structure at the first side of the substrate, wherein the standoff structure extends away from the first side of the substrate for a distance.
11. The device of claim 9 , further comprising a non-conductive paste at the first side of the substrate.
12. The device of claim 9 wherein the substrate includes a via extending from the first side of the substrate to the second side of the substrate, wherein at least one wiring trace lines the via.