Processes for reducing leakage and improving adhesion

1. A method comprising:

forming a metal seed layer on a dielectric layer;

forming a patterned plating mask over the metal seed layer, wherein an opening in the patterned plating mask extends laterally to overlap a first portion of the dielectric layer, and the patterned plating mask overlaps a second portion of the dielectric layer;

plating a conductive feature in the opening;

removing the patterned plating mask to expose portions of the metal seed layer;

etching the exposed portions of the metal seed layer to reveal the second portion of the dielectric layer;

performing a plasma treatment on the dielectric layer; and

forming an additional conductive feature joining the conductive feature.

2. The method of claim 1 further comprising, at a time after the plasma treatment is performed and before the additional conductive feature is formed, performing an etching process on the dielectric layer.

3. The method of claim 2 , wherein the etching process comprises a wet etching process performed using an etching chemical that is capable of etching the metal seed layer.

4. The method of claim 1 , wherein the conductive feature comprises solder, and wherein the method further comprises reflowing the solder.

5. The method of claim 1 , wherein the conductive feature is a metal pillar comprising copper.

6. The method of claim 1 further comprising dispensing an underfill contacting the conductive feature and the additional conductive feature.

7. The method of claim 1 , wherein the plasma treatment is performed using a process gas selected from the group consisting of nitrogen (N 2 ), argon (Ar), and combinations thereof.

8. The method of claim 1 further comprising:

forming a metal post over a buffer dielectric layer;

placing a device die over the buffer dielectric layer;

encapsulating the device die and the metal post in an encapsulant; and

performing a planarization process on the encapsulant to reveal the device die and the metal post, wherein the conductive feature is electrically coupled to one of the device die and the metal post.

9. The method of claim 8 further comprising:

performing an additional plasma treatment process on the buffer dielectric layer and the metal post; and

after the additional plasma treatment process is performed, performing an additional etching process.

10. The method of claim 9 further comprising:

after the additional etching process, performing an oxidation process on the metal post.

11. A method comprising:

forming a conductive feature comprising:

forming a metal seed layer on a dielectric layer;

forming a patterned plating mask over the metal seed layer;

plating a conductive material in the patterned plating mask;

removing the patterned plating mask to expose portions of the metal seed layer; and

etching the exposed portions of the metal seed layer to reveal the dielectric layer;

bombarding the revealed dielectric layer; and

after the bombarding, performing an etching process on the revealed dielectric layer.

12. The method of claim 11 , wherein the bombarding is performed using a process gas comprising nitrogen (N 2 ).

13. The method of claim 11 , wherein the bombarding is performed using a process gas comprising argon (Ar).

14. The method of claim 11 further comprising reflowing the conductive material, with the conductive material comprising solder.

15. The method of claim 11 further comprising:

forming a metal post over a buffer dielectric layer;

encapsulating the metal post in an encapsulant; and

performing a planarization process on the encapsulant to reveal the metal post, wherein the conductive feature is electrically coupled to the metal post.

16. The method of claim 11 further comprising:

placing a device die over a buffer dielectric layer;

encapsulating the device die in an encapsulant; and

performing a planarization process on the encapsulant to reveal the device die, wherein the conductive feature is electrically coupled to the device die.

17. A method comprising:

forming a conductive feature extending into a dielectric layer, wherein the conductive feature overlaps an edge portion of the dielectric layer;

performing a treatment process to bombard the conductive feature and the dielectric layer; and

after the treatment process, performing an etching process using a chemical that is configured to remove a metallic material in the conductive feature.

18. The method of claim 17 , wherein the forming the conductive feature comprises:

depositing a blanket metal layer; and

patterning the blanket metal layer to form the conductive feature, with the conductive feature forming an under-bump metallurgy.

19. The method of claim 17 , wherein the forming the conductive feature comprises:

depositing a metal seed layer extending into the dielectric layer;

forming a patterned plating mask over the metal seed layer;

plating an additional metallic material in the patterned plating mask and over the metal seed layer; and

removing the patterned plating mask.

20. The method of claim 17 further comprising bonding a solder region to the conductive feature.