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 method, comprising:
providing an integrated circuit die having a plurality of solder balls, each of which has a layer of oxide on an outer surface of the ball;
performing a heating process to heat at least the solder balls; and
applying a force that causes 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.
2. The method of claim 1 , wherein the steps recited in claim 1 are performed in an ambient, oxygen-containing environment.
3. The method of claim 2 , wherein the steps recited in claim 1 are performed without applying a flux to the plurality of solder balls.
4. The method of claim 1 , wherein performing the heating process comprises heating at least the solder balls to a temperature that is above a melting point of a material of the solder balls.
5. The method of claim 4 , wherein the substrate comprises a printed circuit board.
6. The method of claim 1 , wherein applying the force comprises applying a force ranging from 5-12 Kg for a duration ranging from 0.5-2 seconds.
7. The method of claim 6 , wherein each of the plurality of piercing bond structures has a substantially triangular cross-sectional configuration.
8. The method of claim 1 , further comprising forming a standoff structure between the integrated circuit die and the substrate.
9. The method of claim 1 , further comprising forming an anti-oxidation layer on at least one of the plurality of piercing bond structures.
10. The method of claim 9 , wherein the anti-oxidation layer includes a first layer with a first thickness of about 2.5 μm and a second layer with a second thickness of about 0.3 μm.
11. The method of claim 9 , wherein the anti-oxidation layer includes a first layer of gold and a second layer of nickel.
12. The method of claim 1 , further comprising determining a distance between the integrated circuit and the substrate at least by controlling the heating process.
13. The method of claim 1 , further comprising controlling a distance between the integrated circuit and the substrate at least by adjusting the force.
14. The method of claim 1 , wherein the plurality of piercing bond structures includes a first piercing bond structure and a second piercing bond structure, wherein the first piercing bond structure has a first size different from a second size of the second piercing bond structure.
15. A method, comprising:
forming a plurality of solder balls on a microelectronic component, wherein the individual solder ball includes an oxide layer;
forming a plurality of piercing bond structures on a substrate, wherein the individual piercing bond structure includes an anti-oxidation layer;
heating at least the solder balls; and
moving the piercing bond structures and/or the microelectronic component to pierce the solder balls and the associated oxide layers;
establishing a conductive connection between the microelectronic component and the piercing bond structures.
16. The method of claim 15 , further comprising forming a standoff structure between the microelectronic component and the substrate.
17. The method of claim 15 , wherein the anti-oxidation layer includes a first layer of gold and a second layer of nickel, and wherein the first layer has a first thickness of about 2.5 μm and the second layer has a second thickness of about 0.3 μm.
18. The method of claim 15 , wherein the plurality of piercing bond structures includes a first piercing bond structure and a second piercing bond structure, wherein the first piercing bond structure has a first size different from a second size of the second piercing bond structure.
19. The method of claim 15 , wherein heating at least the solder balls comprises heating the solder balls to a temperature that is above a melting point of a material of the solder balls.
20. A device, comprising:
a microelectronic component having a plurality of solder balls conductively coupled to bond pads on the microelectronic component, each of the solder balls having an oxide layer on its outer surface;
a substrate having a plurality of piercing bond structures, each of the piercing bond structures penetrating the corresponding oxide layer and extending partially into the corresponding solder ball to establish a conductive connection; and
a standoff structure positioned between the microelectronic component and the substrate, wherein the standoff structure spaces the microelectronic device apart from the substrate by a desired distance.