Method and apparatus for connecting packages onto printed circuit boards

1. A method of forming a device, comprising:

providing an integrated circuit (IC) package comprising a connector and an IC, and a molding compound, the molding compound encapsulating a portion of the connector, wherein a portion of the connector protrudes above a topmost surface of the molding compound;

providing a printed circuit board (PCB) comprising a PCB contact pad;

selectively applying a polymer flux to the portion of the connector that protrudes above the topmost surface of the molding compound; and

after selectively applying the polymer flux, bringing the IC package into contact with the PCB and forming a connection between the PCB contact pad and the connector, wherein the polymer flux covers at least a part of the connector and extends over the topmost surface of the molding compound after the IC package and the PCB are brought into contact.

2. The method of claim 1 , further comprising:

providing a pre-solder on the PCB contact pad; and

forming the connection between the pre-solder on the PCB contact pad and the connector.

3. The method of claim 1 , wherein the polymer flux extends a first distance above the topmost surface of the molding compound and extends a second distance laterally across the topmost surface of the molding compound, the second distance being greater than the first distance.

4. The method of claim 1 , wherein the polymer flux is provided by screen printing, dipping, jetting, or dispensing.

5. The method of claim 1 , wherein the polymer flux is provided on the connector.

6. The method of claim 1 , wherein the polymer flux covering a part of the connector is of a width from about 5 um to about 30 um and a height about from about 5 um to about 50 um.

7. The method of claim 1 , wherein the polymer flux comprises a flux component and a polymer component.

8. The method of claim 1 , wherein the IC package is selected from the group consisting essentially of a quad flat package, a pin grid array package, a ball grid array package, a flip chip package, a three dimensional integrated circuit, a chip scale package, or a package on package device.

9. The method of claim 1 , wherein the IC package further comprises a substrate, a passivation layer on the substrate, a redistribution layer on the passivation layer, and an under bump metal (UBM) pad on the redistribution layer connected to the connector.

10. The method of claim 1 , wherein the connector is made of an electrically conductive solder material selected from the group consisting essentially of Sn, Ni, Au, Ag, Cu, Bi, an alloy, or a combination thereof.

11. A method of forming a device, comprising:

providing an integrated circuit (IC) package comprising a connector and an IC;

providing a printed circuit board (PCB) comprising a PCB contact pad;

forming a molding compound over the connector, wherein the molding compound encapsulates a portion of the connector and has a topmost surface from which a second portion of the connector protrudes;

providing a polymer flux on the connector after forming the molding compound;

connecting the PCB contact pad and the connector with the polymer flux between the connector and the PCB contact pad after forming the molding compound; and

reflowing the device to make a connection between the connector and the PCB contact pad, wherein the polymer flux covers at least a part of the connector, and wherein the polymer flux flows over a portion of the topmost surface of the molding compound.

12. The method of claim 11 , wherein the polymer flux covering a part of the connector is of a width from about 5 um to about 30 um and a height about from about 5 um to about 50 um.

13. A method of forming a device, comprising:

providing a first component having a first connection element formed thereon;

forming a molding compound over the first component;

providing a second component having a second connection element formed thereon;

after forming the molding compound, applying a polymer flux to one of the first connection element and the second connection element, the polymer flux including a fluxing component and a polymer component wherein the step of applying a polymer flux to one of the first connection element and the second connection element includes leaving channels that allow volatile gasses to escape;

aligning and contacting the first connection element to the second connection element; and

reflowing the first connection element and the second connection element to form a bond therebetween, wherein the polymer component of the polymer flux covers at least a part of the first connection element after the step of reflowing.

14. The method of claim 13 , wherein the step of providing a first component having a first connection element formed thereon includes forming a solder ball on the first component.

15. The method of claim 13 , wherein the step of providing a second component having a second connection element formed thereon includes forming a pre-solder on a contact pad on the second component.

16. The method of claim 13 , wherein the step of applying a polymer flux to one of the first connection element and the second connection element includes dipping the first connection element in the polymer flux.

17. The method of claim 13 , wherein the step of applying a polymer flux to one of the first connection element and the second connection element includes applying polymer flux to individual ones of a plurality of first connection elements.

18. The method of claim 13 , wherein the fluxing component of the polymer flux is removed during the step of reflowing.