Integrated circuit package with pre-wetted contact sidewall surfaces

1. A method, comprising:

encapsulating a lead frame strip having individual lead frames, wherein the lead frame strip includes IC dies attached to the individual lead frames, wherein at least two adjacent individual lead frames share a contact element;

partially sawing a trench into the encapsulated lead frame strip adjacent to the contact element to form a contact sidewall surface;

depositing a pre-tinning material into a portion of the trench;

reflowing the pre-tinning material to wick up and cover the contact sidewall surface with the pre-tinning material; and

separating the encapsulated lead frame strip into individual IC packages each having contacts sidewall surfaces in which the pre-tinning material forms a protective layer on the contact sidewall surfaces.

2. The method of claim 1 , in which the layer of pre-tinning material includes silver nanoparticles.

3. The method of claim 1 , in which the layer of pre-tinning material is solder.

4. The method of claim 1 , in which the pre-tinning material is deposited using an ink jet printer.

5. The method of claim 1 , in which separating the encapsulated frame strip into individual IC packages produces a thinner kerf than the plurality of trenches.

6. The method of claim 1 , further comprising back filling any remaining unfilled portion of the plurality of trenches prior to separating the encapsulated lead frame strip into individual IC packages.

7. A method for performing automatic visual inspection (AVI), the method comprising:

soldering an integrated circuit (IC) package to pads on a substrate, wherein the IC package has contacts, wherein each of the contacts has a lower surface and a sidewall surface, and wherein a substantial portion of the sidewall surface of each of the contacts is covered with a protective layer of material comprising silver nanoparticles;

visually inspecting a solder profile of a solder joint between a contact on the IC package and a pad on the substrate; and

failing the joint when the solder profile does not include a fillet that covers a substantial portion of the contact sidewall surface.

8. The method of claim 7 , further including passing the joint when the solder profile includes a fillet that covers a substantial portion of the contact sidewall surface.

9. The method of claim 7 , wherein the substantial portion of the contact sidewall surface comprises at least 90% of the contact sidewall surface.

10. The method of claim 8 , wherein the substantial portion of the contact sidewall surface comprises at least 90% of the contact sidewall surface.

11. The method, comprising:

encapsulating a lead frame strip having individual lead frames, wherein the lead frame strip includes IC dies attached to the individual lead frames, wherein at least two adjacent individual lead frames share a contact element;

partially sawing a trench into the encapsulated lead frame strip adjacent to the contact element to form a contact sidewall surface;

depositing a pre-tinning material into a portion of the trench;

reflowing the pre-tinning material to wick up and cover the contact sidewall surface with the pre-tinning material;

filling any remaining portion of the trench with a fill material; and

separating the encapsulated lead frame strip into individual IC packages each having contacts sidewall surfaces in which the pre-tinning material forms a protective layer on the contact sidewall surfaces.

12. The method of claim 11 , wherein the fill material is an epoxy compound.

13. The method of claim 12 , wherein the epoxy compound is mold compound.

14. A method, comprising:

encapsulating a lead frame strip having individual lead frames, wherein the lead frame strip includes IC dies attached to the individual lead frames, wherein at least two adjacent individual lead frames share a contact element;

partially sawing a trench into the encapsulated lead frame strip adjacent to the contact element to form a contact sidewall surface;

depositing a pre-tinning material into the trench;

reflowing the pre-tinning material to cover the contact sidewall surface with the pre-tinning material, at least a portion of the trench remaining open after reflowing; and

separating the encapsulated lead frame strip into individual IC packages each having contacts sidewall surfaces in which the pre-tinning material forms a protective layer on the contact sidewall surfaces.

15. The method of claim 14 , in which the layer of pre-tinning material includes silver nanoparticles.

16. The method of claim 14 , in which the layer of pre-tinning material is solder.

17. The method of claim 14 , in which the pre-tinning material is deposited using an ink jet printer.

18. The method of claim 14 , in which separating the encapsulated frame strip into individual IC packages produces a thinner kerf than the plurality of trenches.

19. The method of claim 14 , further comprising back filling the plurality trenches prior to separating the encapsulated lead frame strip into individual IC packages.

20. The method of claim 14 , wherein the fill material is an epoxy compound.

21. The method of claim 20 , wherein the epoxy compound is mold compound.

22. A method for performing automatic visual inspection (AVI), the method comprising:

soldering an integrated circuit (IC) package to pads on a substrate, wherein the IC package has contacts, wherein each of the contacts has a lower surface and a sidewall surface, and wherein a substantial portion of the sidewall surface of each of the contacts is covered with a protective layer of material comprising tin nanoparticles;

visually inspecting a solder profile of solder joint between a contact on the IC package and a pad on the substrate; and

failing the joint when the solder profile does not include a fillet that covers a substantial portion of the contact sidewall surface.

23. The method of claim 22 , further including passing the joint when the solder profile includes a fillet that covers a substantial portion of the contact sidewall surface.

24. The method of claim 22 , wherein the substantial portion of the contact sidewall surface comprises at least 90% of the contact sidewall surface.

25. The method of claim 23 , wherein the substantial portion of the contact sidewall surface comprises at least 90% of the contact sidewall surface.

26. A method for performing :automatic visual inspection (AVI), the method comprising:

soldering an integrated circuit (IC) package to pads on a substrate, wherein the IC package has contacts, wherein each of the contacts has a lower surface and a sidewall surface, and wherein a substantial portion of the sidewall surface of each of the contacts is covered with a protective layer of material comprising gold nanoparticles;

visually inspecting a solder profile of a solder joint between a contact on the IC package and a pad on the substrate; and

failing the joint when the solder profile does not include a fillet that covers a substantial portion of the contact sidewall surface.

27. The method of claim 26 , further including passing the joint when the solder profile includes a fillet that covers a substantial portion of the contact sidewall surface.

28. The method of claim 26 , wherein the substantial portion of the contact sidewall surface comprises at least 90% of the contact sidewall surface.

29. The method of claim 27 , wherein the substantial portion of the contact sidewall surface comprises at least 90% of the contact sidewall surface.