Process for through silicon via filling

• US 8,722,539 B2
• Filed: 10/11/2011
• Issued: 05/13/2014
• Est. Priority Date: 08/18/2008
• Status: Active Grant

• Current Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Original Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Inventors: Reid, Jonathan D., Wang, Katie Qun, Willey, Mark J.
• Primary Examiner(s): Mandala, Michelle
• Application Number:
  US13/270,897
• Publication Number:
  US 20120031768A1
• Time in Patent Office: 945 Days
• Field of Search: 438/633, 438/637, 438/638, 438/678, 438/687, 257/E21.586
• US Class Current: 438/678
• CPC Class Codes: C25D 17/001 Apparatus specially adapted for electrolytic coating of wafers, e.g. semiconductors or solar cells
• CPC Class Codes: C25D 21/12 Process control or regulation controlling or regulating in general G05
• CPC Class Codes: C25D 3/38 of copper
• CPC Class Codes: C25D 7/123 Semiconductors first coated with a seed layer or a conductive layer
• CPC Class Codes: H01L 21/2885 using an external electrical current, i.e. electro-deposition
• CPC Class Codes: H01L 21/76898 formed through a semiconductor substrate
• CPC Class Codes: H01L 2224/0554 External layer
• CPC Class Codes: H01L 2224/0555 Shape
• CPC Class Codes: H01L 2224/0556 Disposition
• CPC Class Codes: H01L 2224/05573 Single external layer
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/13025 the bump connector being disposed on a via connection of the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/16 of an individual bump connector
• CPC Class Codes: H01L 2225/06513 Bump or bump-like direct electrical connections between devices, e.g. flip-chip connection, solder bumps
• CPC Class Codes: H01L 2225/06541 Conductive via connections through the device, e.g. vertical interconnects, through silicon via [TSV]
• CPC Class Codes: H01L 25/50 Multistep manufacturing processes of assemblies consisting of devices, each device being of a type provided for in group H01L27/00 or H01L29/00 H01L21/50 takes precedence
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details

Abstract

A semiconductor electroplating process deposits copper into the through silicon via hole to completely fill the through silicon via in a substantially void free is disclosed. The through silicon via may be more than about 3 micrometers in diameter and more that about 20 micrometers deep. High copper concentration and low acidity electroplating solution is used for deposition copper into the through silicon vias.

Claims

1. A method of plating a through silicon via for connecting at least two integrated circuits, the method comprising:

providing a structure containing a through silicon via hole, the structure comprising a seed layer within the through silicon via hole;

pretreating the seed layer using one or more liquids selected from the group consisting of water, a dilute acidic solution, a dilute basic solution, a surfactant containing solution, and the plating solution;

contacting the pretreated seed layer with a plating solution having copper ions at a concentration of at least about 40 grams per liter; and

while contacting the pretreated seed layer with the plating solution, plating copper into the through silicon via hole to completely fill the through silicon via hole,

wherein a deposition rate during the plating is higher at the bottom of the through silicon via hole than near the opening of the through silicon via hole.

2. The method of claim 1, wherein pretreating the seed layer comprises etching away at least a portion of the seed layer.

3. The method of claim 1, further comprising applying voltage to the pretreated seed layer prior to contacting the pretreated seed layer with the plating solution.

4. The method of claim 1, wherein the plating solution further comprises an accelerator at a concentration of less than 200 ppm.

5. The method of claim 4, wherein the concentration of the accelerator is 2.5 ml/L.

6. The method of claim 4, wherein the concentration of the accelerator is 3.5 ppm.

7. The method of claim 4, wherein the accelerator comprises one or more of the following functional groups:

a polar sulfur group, an oxygen group, and a nitrogen group.

8. The method of claim 4, wherein the accelerator comprises a polar sulfur group.

9. The method of claim 4, wherein the plating solution further comprises a suppressor at a concentration higher than then concentration of the accelerator.

10. The method of claim 1, wherein the plating solution comprises a suppressor at a concentration of between 5 ppm and 1,000 ppm.

11. The method of claim 1, wherein the plating solution comprises a leveler at a concentration of between 1 ppm and 100 ppm.

12. The method of claim 1, wherein the plating solution comprises chloride ions at a concentration of no greater than about 2 ppm.

13. The method of claim 1, wherein the plating solution is free of chloride ions.

14. The method of claim 1, wherein the plating solution further comprises an oxidizing agent.

15. The method of claim 14, wherein the oxidizing agent comprises a hydrogen peroxide solution comprising 30% hydrogen peroxide by weight and the concentration of the hydrogen peroxide solution in the plating solution is between about 0.0025 ml per liter and 50 ml per liter.

16. The method of claim 14, wherein the oxidizing agent comprises one or more of the following:

elemental oxygen, cerium ions, and iron ions.

17. The method of claim 1, wherein the plating solution further comprises a reducing agent, wherein the reducing agent has a concentration gradient in the through silicon via hole, and wherein the reducing agent impacts oxidation of the copper.

18. The method of claim 1, wherein the plating solution is maintained at a temperature of between about 40°

C. and 75°

C. for at least a fraction of the time while plating copper into the through silicon via hole.

19. The method of claim 1, wherein the plating solution comprises a sulfuric acid at a concentration of about 10 g/L.

20. The method of claim 1, wherein the plating solution has a pH of between about 2 and 6.

21. The method of claim 1, wherein the plating solution has a pH of between about 3 and 5.

22. The method of claim 1, wherein the plating solution is maintained at least about a room temperature for at least a fraction of the time while plating copper into the through silicon via hole.

23. The method of claim 1, wherein copper is plated into the through silicon via hole with substantially no net deposition on a field region of the structure.

24. The method of claim 1, wherein the plating solution further comprises a leveler, the leveler interacting with the copper ions at a field region of the structure.

25. The method of claim 1, wherein the plating solution further comprises a leveler, the leveler comprising a nitrogen containing functional group that forms a complex with the copper ions on a field region of the structure.

26. A copper plating solution for depositing copper in a through silicon via for connecting at least two integrated circuits, the copper plating solution comprising:

copper ions at a concentration of at least about 40 grams per liter;

sulfuric acid;

an oxidizing agent, the oxidizing agent comprises one or more of the following;

a hydrogen peroxide solution, elemental oxygen, cerium ions, and iron ions;

an accelerator comprising one or more of the following functional groups;

a polar sulfur group, an oxygen group, and a nitrogen group;

a suppressor at a concentration higher than a concentration of the accelerator; and

a leveler at a concentration higher than the concentration of the accelerator.

27. The copper plating solution of claim 26, wherein the oxidizing agent configured to oxidize the deposited copper on a wafer field at a rate of between about 200 Å

/minute and 3000 Å

/minute when a current is not applied to wafer.

28. The copper plating solution of claim 26, wherein the concentration of the accelerator in the copper plating solution is less than 200 ppm.

29. The copper plating solution of claim 26, wherein the concentration of the suppressor in the plating solution is between 5 ppm and 1,000 ppm.

30. The copper plating solution of claim 26, wherein the concentration of the leveler in the plating solution is between 1 ppm and 100 ppm.

31. The copper plating solution of claim 26, wherein the copper plating solution is free of chloride ions.