Cobalt filling of interconnects

Patent metadata

Field	Value
Publication number	US-11401618-B2
Application number	US-202117222058-A
Country	US
Kind code	B2
Filing date	Apr 5, 2021
Priority date	Jul 5, 2017
Publication date	Aug 2, 2022
Grant date	Aug 2, 2022

Abstract

Compositions and methods of using such compositions for electroplating cobalt onto semiconductor base structures comprising submicron-sized electrical interconnect features are provided herein. The interconnect features are metallized by contacting the semiconductor base structure with an electrolytic composition comprising a source of cobalt ions, a suppressor, a buffer, and one or more of a depolarizing compound and a uniformity enhancer. Electrical current is supplied to the electrolytic composition to deposit cobalt onto the base structure and fill the submicron-sized features with cobalt. The method presented herein is useful for superfilling interconnect features.

First claim

The invention claimed is:

1. A composition for the electrolytic deposition of cobalt comprising:
a source of cobalt ions;
an acetylenic suppressor compound, wherein the acetylenic suppressor compound is an acetylenic alcohol compound or a derivative thereof having a terminal triple bond;
a buffering agent; and
1000 to 4000 of a uniformity enhancer, wherein the uniformity enhancer comprises an aminic polyol compound or a derivative thereof; and
optionally, a depolarizing compound;
wherein the composition does not contain an accelerator;
wherein the composition has a concentration of divalent sulfur compounds of less than 1 mg/L.

2. A composition according to claim 1 , wherein the composition is at least substantially free of any functional concentration of reducing agents that are capable of reducing cobaltous ions (Co 2+ ) to metallic cobalt (Co 0 ).

3. A composition according to claim 1 further comprising a stress reducer, wherein the stress reducer comprises saccharin, at a concentration of between about 10 and about 300 ppm.

4. A composition according to claim 1 , wherein the acetylenic suppressor compound is selected from the group consisting of propoxylated propargyl alcohol, ethoxylated propargyl alcohol, a reaction product of ethoxylated propargyl alcohol and 1,4-butanediol diglycidyl ether, diethylene glycol bis(2-propynyl) ether, and combinations of one or more of the foregoing.

5. A composition according to claim 4 , wherein the acetylenic suppressor compound comprises ethoxylated propargyl alcohol.

6. A composition according to claim 1 , wherein the buffering agent comprises boric acid.

7. A composition according to claim 1 , wherein the pH is between about 1.5 and about 7.

8. A composition according to claim 7 , wherein the pH is between about 2.5 and about 3.5.

9. A composition according to claim 1 , comprising:
between about 1 and about 50 g/L cobalt ions;
between about 1 and about 100 mg/L of the acetylenic suppressor compound;
between about 5 and about 50 g/L, buffer; and
the balance, substantially water.

10. A composition according to claim 1 comprising less than about 20 ppb copper ions.

11. A composition according to claim 1 , wherein the uniformity enhancer is selected from the group consisting of ethoxylated, propoxylated triisopropanolamine, ethoxylated, propoxylated ethylene diamine, ethoxylated, propoxylated diethylene triamine, ethoxylated, propoxylated triethylenetetramine and combinations of one or more of the foregoing.

12. A composition according to claim 1 , wherein the depolarizing compound is present and is selected from the group consisting of sodium propargyl sulfonate, acetylenedicarboxylic acid, acrylic acid, propiolic acid, and mixtures thereof.

13. A composition according to claim 12 , wherein the depolarizing compound comprises sodium propargyl sulfonate.

14. A composition for the electrolytic deposition of cobalt comprising:
between about 5 and about 10 g/L cobalt ions;
between about 15 and about 65 mg/L of the acetylenic suppressor compound selected from the group consisting of propargyl alcohol and ethoxylated propargyl alcohol:
between about 1000 and about 4000 mg/L of the uniformity enhancer;
between about 15 and about 40 g/L buffer; and
the balance substantially water;
wherein the composition does not contain an accelerator.

15. A method for electroplating a cobalt deposit onto a semiconductor base structure, wherein the semiconductor base structure comprises a metallizing substrate comprising submicron-sized electrical interconnect features, the method comprising the steps of
a) contacting the metallizing substrate with an electrolytic composition comprising:
a source of cobalt ions;
an acetylenic suppressor compound, wherein the acetylenic suppressor compound is an acetylenic alcohol compound or a derivative thereof having a terminal triple bond;
a buffering agent; and
1000 to 4000 mg/L of a uniformity enhancer, wherein the uniformity enhancer comprises an aminic polyol compound or a derivative thereof;
optionally,
a depolarizing compound;
wherein the composition does not contain an accelerator; and

wherein the composition is at least substantially free of divalent sulfur compounds;
b) supplying electrical current to the electrolytic composition to deposit cobalt onto the base structure and fill the submicron-sized electrical interconnect features with cobalt.

16. The method according to claim 15 , wherein the electrolytic composition is at least substantially free of any functional concentration of reducing agents capable of reducing cobaltous ions (Co 2+ ) to metallic cobalt (Co 0 ).

17. The method according to claim 15 , wherein the electrolytic composition is at least substantially free of copper ions, nickel ions, and iron ions.

18. The method according to claim 15 , wherein the acetylenic suppressor compound is selected from the group consisting of propargyl alcohols, ethoxylated propargyl alcohol, a reaction product of ethoxylated propargyl alcohol and 1,4-butanediol diglycidyl ether, diethylene glycol bis(2-propynyl) ether, 1,4-bis(2-hydroxyethoxy)-2-butyne, 2-butyne-1,4-diol, ethoxylated and/or propoxylated propargyl alcohol compounds and mixtures of one or more of the foregoing.

19. The method according to claim 18 , wherein the acetylenic suppressor compound comprises ethoxylated propargyl alcohol.

20. The method according to claim 15 , wherein the uniformity enhancer is selected from the group consisting of ethoxylated, propoxylated triisopropanolamine, ethoxylated, propoxylated ethylene diamine, ethoxylated, propoxylated diethylene triamine, ethoxylated, propoxylated triethylenetetramine and combinations of one or more of the foregoing.

21. The method according to claim 15 , wherein the electrolytic composition has a pH between about 1.5 and about 7.

22. The method according to claim 21 , wherein the electrolytic composition has a pH between about 2.5 and about 3.5.

23. The method according to claim 15 , wherein the electrolytic composition further comprises a stress reducer, wherein the stress reducer comprises saccharin in a concentration between about 10 and about 300 ppm.

24. The method according to claim 15 , wherein the submicron-sized electrical, interconnect features comprise cavities in said semiconductor base structure that are superfilled, by rapid bottom-up deposition of cobalt.

25. The method according to claim 24 , wherein electrodeposition of cobalt fills the submicron-sized electrical interconnect features from the bottom up by rapid bottom-up deposition at a rate of growth in the vertical direction which is greater than a rate of growth in the horizontal direction.

26. The method according to claim 15 , wherein the internal tensile stresses in cobalt filling the submicron-sized electrical interconnect features are between about 0 and about 500 MPa.

27. The method according to claim 15 , wherein the entry dimension of the submicron-sized electrical interconnect features is less than about 50 nm.

28. The method according to claim 27 , wherein the submicron-sized electrical interconnect features have an aspect ratio of greater than about 3:1 or greater than about 4:1 or between about 4:1 and about 10:1.

29. The method according to claim 27 , wherein the submicron-sized electrical interconnect features have an aspect ratio of gr

Assignees

• Macdermid Enthone Inc

Inventors

• Commander John
• Whitten Kyle
• Paneccasio Jr Vincent
• Sun Shaopeng
• Yakobson Eric
• Han Jianwen
• Najjar Elie

Classifications

• H10W20/4437

  the principal metal being a transition metal · CPC title

• H10P14/47

  Electrolytic deposition, i.e. electroplating; Electroless plating · CPC title

• H10W20/057

  by selectively depositing, e.g. by using selective CVD or plating · CPC title

• H10W20/056

  by filling conductive material into holes, grooves or trenches · CPC title

• C25D5/02

  Electroplating of selected surface areas · CPC title