Method for controlling conductor deposition on predetermined portions of a wafer
View Patent ↗A plating apparatus and method for deposition of a conductive material on a semiconductor wafer having surface portions and cavity portions. A differential in an adsorbed concentration of an additive, including accelerators or suppressors, between a surface portion and a cavity portion of a wafer surface is established in a chamber. A mask or sweeper may be used to establish the differential. After establishing the differential in the chamber, the conductive material is electrodeposited to form a conductive layer on the surface in another chamber.
1. A method of electrodepositing a conductive material onto a surface of a wafer, wherein the surface includes a surface portion and a cavity portion, the method comprising:
establishing a differential in an adsorbed concentration of an additive between the surface portion and the cavity portion of the surface in a first chamber;
transporting the wafer to a second chamber after establishing the differential; and
electrodepositing the conductive material to form a conductive layer on the surface having the differential in the second chamber.
2. The method of claim 1 , wherein establishing a differential includes sweeping the surface with a sweeper.
3. The method of claim 2 , wherein the additive comprises an accelerator.
4. The method of claim 2 , wherein the sweeper includes a pad configured to touch the surface of the wafer while the differential is being established.
5. The method of claim 1 , further including applying the additive to the surface of the wafer at least one of before and during establishing the differential.
6. The method of claim 5 , wherein applying comprises injecting the additive towards the surface using nozzles.
7. The method of claim 6 , wherein the additive comprises an accelerator.
8. The method of claim 1 , further including holding the wafer by a wafer carrier.
9. The method of claim 8 , wherein transporting is performed with the wafer carrier.
10. The method of claim 8 , wherein transporting is performed with another wafer carrier.
11. The method of claim 1 , wherein electrodepositing is performed in the second chamber comprising a plating unit with an electrode and a plating solution.
12. The method of claim 11 , wherein the plating solution includes suppressor additives.
13. The method of claim 12 , further including sweeping the surface with another sweeper in the second chamber.
14. The method of claim 1 , wherein establishing the differential, transporting the wafer and electrodepositing the conductive material are carried out while the wafer is held by a wafer carrier.
15. The method of claim 1 , further including rinsing the wafer after establishing the differential.
16. The method of claim 15 , further including drying the wafer after rinsing.
17. The method of claim 16 , wherein rinsing and drying are performed in the first chamber.
18. The method of claim 1 , further including cleaning the wafer after electrodepositing.
19. The method of claim 18 , wherein cleaning is carried out in the first chamber.
20. The method of claim 1 , wherein the conductive material is copper.
21. The method of claim 2 , wherein sweeping the surface comprises applying a pressure onto the surface with the sweeper, the pressure between about 0.1 psi and about 2 psi.
22. The method of claim 9 , wherein transporting the wafer comprises moving the wafer carrier horizontally between the first chamber and the second chamber.
23. The method of claim 9 , wherein transporting the wafer comprises moving the wafer carrier vertically between the first chamber and the second chamber.
24. The method of claim 18 , wherein rinsing is carried out in the first chamber.
25. The method of claim 1 , wherein establishing a differential comprises not applying power to the surface in the first chamber.
26. The method of claim 1 , further comprising:
before establishing the differential, applying power to the surface;
during establishing the differential, not applying power to the surface; and
after establishing the differential, applying power to the surface.
27. The method of claim 1 , further comprising, after establishing the differential, applying power to the surface.
28. The method of claim 1 , wherein establishing the differential comprises soaking the surface with a solution comprising the additive.
29. The method of claim 28 , wherein soaking the surface is for a duration of between about 5 seconds and about 200 seconds.
30. The method of claim 28 , wherein soaking the surface is for a duration of between about 10 seconds and about 60 seconds.
31. The method of claim 28 , wherein soaking the surface comprises rotating the wafer between 1 rpm and 100 rpm.
32. The method of claim 28 , wherein soaking the surface comprises rotating the wafer between 5 rpm and 50 rpm.
33. The method of claim 1 , wherein the electrodepositing comprises plating from a solution substantially free of additives.
34. The method of claim 1 , wherein the electrodepositing comprises plating from a solution comprising a second additive different from the additive.
35. The method of claim 34 , wherein the additive comprises an accelerator.
36. The method of claim 35 , wherein the second additive comprises a suppressor.
37. The method of claim 34 , wherein the second additive comprises a suppressor.
38. The method of claim 1 , wherein the electrodepositing comprises plating from a solution comprising a suppressor.
39. The method of claim 1 , after electrodepositing the conductive material, the conductive material over the cavity portion is thicker than the conductive material over the surface portion.
40. The method of claim 39 , wherein the cavity portion of the surface comprises a large cavity.
41. The method of claim 40 , wherein the cavity portion of the surface further comprises small cavities.
42. The method of claim 41 , wherein the conductive material over the large cavity is thicker than the conductive material over the small cavities.