Cobalt filling of interconnects

Patent metadata

Field	Value
Publication number	US-11035048-B2
Application number	US-201715641756-A
Country	US
Kind code	B2
Filing date	Jul 5, 2017
Priority date	Jul 5, 2017
Publication date	Jun 15, 2021
Grant date	Jun 15, 2021

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 and configured for filling submicron features of a semiconductor base structure, the composition comprising:
a source of cobalt ions;
a suppressor compound, wherein the suppressor compound comprises an acetylenic suppressor selected from the group consisting of propoxylated propargyl alcohol, a reaction product of ethoxylated propargyl alcohol and 1,4-butanediol diglycidyl ether, diethylene glycol bis(2-propynyl) ether, 4-pentyne-1-ol, 2-methyl-3-butyne-2-ol, 3-methyl-1-pentyne-3-ol, 3-butyne-2-ol, and combinations of one or more of the foregoing;
a buffering agent; and
a uniformity enhancer, wherein the uniformity enhancer comprises an aminic polyol compound or a derivative thereof;
wherein the composition does not contain an accelerator;
wherein the composition has a concentration of divalent sulfur compounds of less than 1 mg/l;
wherein the composition is free of nickel ions, and
wherein the composition is configured for electrodepositing cobalt with total impurities of C, O, N, Cl and S less than 5000 ppm by weight in deposit;
wherein the presence of the uniformity enhancer in the composition improves uniformity without a negative effect on fill performance such that the cobalt electrodeposit exhibits a uniform deposit thickness distribution and smooth morphology and promotes a seam-free, void-free cobalt electrodeposit in the submicron features.

2. A composition according to claim 1 , wherein the composition is 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.

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

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

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

7. A composition according to claim 6 , wherein the pH is between about 2.5 and about 3.5.

8. A composition according to claim 1 , consisting essentially of:
between about 1 and about 50 g/L cobalt ions;
between about 1 and about 100 mg/L of the suppressor compound;
between about 10 and about 4000 mg/L of the uniformity enhancer;
between about 5 and about 50 g/L of the buffering agent; and
the balance substantially water.

9. A composition according to claim 8 , consisting essentially of:
between about 5 and about 10 g/L cobalt ions;
between about 15 and about 65 mg/L of the suppressor;
between about 100 and about 1000 mg/L of the uniformity enhancer;
between about 15 and about 40 g/L of the buffering agent; 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 composition further comprises a depolarizing compound 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 and configured for filling submicron features of a semiconductor base structure, the composition comprising:
a source of cobalt ions;
a suppressor compound, wherein the suppressor compound comprises an acetylenic suppressor selected from the group consisting of propoxylated propargyl alcohol, a reaction product of ethoxylated propargyl alcohol and 1,4-butanediol diglycidyl ether, diethylene glycol bis(2-propynyl) ether, 4-pentyne-1-ol, 2-methyl-3-butyne-2-ol, 3-methyl-1-pentyne-3-ol, 3-butyne-2-ol, and combinations of one or more of the foregoing;
a buffering agent;
a depolarizing compound selected from the group consisting of sodium propargyl sulfonate, acetylenedicarboxylic acid, acrylic acid, propiolic acid, and mixtures thereof; and
a uniformity enhancer, wherein the uniformity enhancer comprises an aminic polyol compound or a derivative thereof;
wherein the composition does not contain an accelerator;
wherein the composition has a concentration of divalent sulfur compounds of less than 1 mg/l; and
wherein the composition is free of nickel ions, wherein the composition is capable of electrodepositing cobalt with total impurities of C, O, N, Cl and S less than 5000 ppm by weight in deposit.

15. A composition for the electrolytic deposition of cobalt and configured for filling submicron features of a semiconductor base structure, the composition comprising:
a source of cobalt ions;
an acetylenic suppressor compound;
a buffering agent; and
a uniformity enhancer, wherein the uniformity enhancer comprises ethoxylated, propoxylated triisopropanolamine;
wherein the composition does not contain an accelerator;
wherein the composition has a concentration of divalent sulfur compounds of less than 1 mg/l;
wherein the composition is free of nickel ions, and
wherein the composition is configured for electrodepositing cobalt with total impurities of C, O, N, Cl and S less than 5000 ppm by weight in deposit;
wherein the presence of the uniformity enhancer in the composition improves uniformity without a negative effect on fill performance such that the cobalt electrodeposit exhibits a uniform deposit thickness distribution and smooth morphology and promotes a seam-free, void-free cobalt electrodeposit in the submicron features.

16. The composition according to claim 15 , wherein the acetylenic suppressor comprise ethoxylated propargyl alcohol.

17. 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;
a suppressor compound, wherein the suppressor compound comprises an acetylenic suppressor selected from the group consisting of propoxylated propargyl alcohol, a reaction product of ethoxylated propargyl alcohol and 1,4-butanediol diglycidyl ether, diethylene glycol bis(2-propynyl) ether, 4-pentyne-1-ol, 2-methyl-3-butyne-2-ol, 3-methyl-1-pentyne-3-ol, 3-butyne-2-ol, and combinations of one or more of the foregoing;
a buffering agent; and
a uniformity enhancer, wherein the uniformity enhancer comprises an aminic polyol compound or a derivative thereof;
wherein the composition does not contain an accelerator or a depolarizing compound;

wherein the composition has a concentration of divalent sulfur compounds of less than 1 mg/l, and
wherein the composition is free of nickel ions; and
b) supplying electrical current to the electrolytic composition to deposit cobalt onto the semiconductor base structure and superfill the submicron-sized electrical interconnect features with cobalt by bottom-up deposition, wherein the cobalt deposit is seam-free in the submicron-sized electric

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

• C25D3/18

  Heterocyclic compounds · CPC title