Processes for reducing leakage and improving adhesion
A method includes forming a metal seed layer on a dielectric layer, and forming a patterned mask over the metal seed layer. An opening in the patterned mask is over a first portion of the dielectric layer, and the patterned mask overlaps a second portion of the dielectric layer. The method further includes plating a metal region in the opening, removing the patterned mask to expose portions of the metal seed layer, etching the exposed portions of the metal seed layer, performing a plasma treatment on a surface of the second portion of the dielectric layer, and performing an etching process on the surface of the second portion of the dielectric layer.
1. A method comprising:
forming a metal seed layer on a first dielectric layer;
plating a metal region over the metal seed layer;
etching portions of the metal seed layer to reveal a portion of the first dielectric layer;
performing a first plasma treatment on a surface of the portion of the first dielectric layer; and
after the first plasma treatment, removing loose metal particles that are on the surface of the portion of the first dielectric layer.
2. The method of claim 1 further comprising:
forming a patterned plating mask over the metal seed layer, wherein the metal region is plated into an opening in the patterned plating mask; and
after the metal region is plated, removing the patterned plating mask to expose portions of the metal seed layer.
3. The method of claim 1 , wherein the removing loosen metal particles is performed by etching the loose metal particles using an etching chemical.
4. The method of claim 3 , wherein the etching chemical is capable of etching the metal seed layer.
5. The method of claim 4 , wherein the metal seed layer comprises a first sub layer and a second sub layer over the first sub layer, and wherein the etching chemical is capable of etching the first sub layer of the metal seed layer.
6. The method of claim 3 further comprising:
after the portion of the first dielectric layer is exposed to the etching chemical, performing a second plasma treatment on the metal region.
7. The method of claim 1 further comprising:
placing a device die on the first dielectric layer; and
encapsulating the metal region and the device die in an encapsulant.
8. The method of claim 1 , wherein the first plasma treatment is performed using a process gas comprising oxygen and an additional gas, wherein the additional gas comprises nitrogen, argon, or combinations thereof.
9. The method of claim 1 further comprising:
bonding a solder region to the metal region; and
dispensing an underfill to encapsulate the solder region.
10. The method of claim 9 , wherein the first plasma treatment and the etching the portions of the metal seed layer are performed after the solder region is bonded to the metal region.
11. A method comprising:
forming a metal region over a dielectric layer;
performing a first plasma treatment to bombard the dielectric layer; and
performing a wet etching process, with a surface of the dielectric layer exposed to a chemical used for the wet etching process.
12. The method of claim 11 , wherein the first plasma treatment is performed before the wet etching process, and the first plasma treatment is performed using a process gas comprising oxygen.
13. The method of claim 12 further comprising:
after the wet etching process, performing a second plasma treatment on the metal region and the dielectric layer, wherein the second plasma treatment is performed using an additional process gas comprising oxygen.
14. The method of claim 13 , wherein an oxide layer is generated on a surface of the metal region by the second plasma treatment, and the method further comprises encapsulating the oxide layer and the metal region in an encapsulant.
15. The method of claim 11 , wherein the forming the metal region comprises:
forming a metal seed layer having a bottom portion contacting the dielectric layer; and
plating the metal region on the metal seed layer, wherein the wet etching process is performed using the chemical, and the chemical is configured to etch the bottom portion of the metal seed layer.
16. A method comprising:
forming a metal post protruding higher than a dielectric layer;
bombarding a surface layer of the dielectric layer;
after the bombarding, performing a plasma treatment on the metal post; and
after the plasma treatment, performing an etching process to etching metal particles on the dielectric layer.
17. The method of claim 16 further comprising, after the bombarding and before the plasma treatment, exposing a surface of the dielectric layer to an etching chemical to perform the etching process.
18. The method of claim 17 , wherein the dielectric layer remains after the dielectric layer is exposed to the etching chemical.
19. The method of claim 16 , wherein the surface layer of the dielectric layer is bombarded using a process gas comprising argon and oxygen.
20. The method of claim 16 further comprising:
encapsulating the metal post and a device die in molding compound.