Cobalt chemistry for smooth topology

Patent metadata

Field	Value
Publication number	US-11230778-B2
Application number	US-201916713871-A
Country	US
Kind code	B2
Filing date	Dec 13, 2019
Priority date	Dec 13, 2019
Publication date	Jan 25, 2022
Grant date	Jan 25, 2022

Abstract

An electroplated cobalt deposit and a method of electrodepositing cobalt on a surface to produce a level deposit across the surface of the substrate. The cobalt electrolyte contains (1) a source of cobalt ions; (2) boric acid; (3) a pH adjuster; and (4) an organic additive, which contains a suppressor. The electroplated cobalt deposit exhibits a level surface such that the thickness difference across substantially the entire surface of the substrate of less than about 200 nm.

First claim

What is claimed is:

1. A method of electrodepositing cobalt onto a substrate comprising recessed features and non-feature areas, wherein the cobalt deposit exhibits a thickness difference across the surface of the substrate of less than about 200 nm the method comprising:
a) receiving the substrate in an electroplating chamber;
b) immersing the substrate into a cobalt electrolyte, the cobalt electrolyte comprising:
(1) a source of cobalt ions;
(2) boric acid;
(3) a pH adjuster; and
(4) an organic additive, wherein the organic additive comprises a suppressor; and

c) electroplating cobalt into the features and onto the non-feature areas for a period of time and under conditions to achieve a level, seam-free, bottom-up fill in the recessed features and plating on the non-feature areas;
wherein the cobalt deposit exhibits a potentiodynamically measured hysteresis loop in a cyclic voltammetry scan at a current density in a range of 5 to about 10 mA/cm 2 of less than about 50 mV.

2. The method according to claim 1 , wherein the substrate has a cobalt seed layer disposed thereon and the cobalt is electrodeposited onto the cobalt seed layer.

3. The method according to claim 1 , wherein the electroplated cobalt deposit exhibits a thickness difference of less than about 100 nm.

4. The method according to claim 3 , wherein the electroplated cobalt deposit exhibits a thickness difference of less than about 75 nm.

5. The method according to claim 4 , wherein the electroplated cobalt deposit exhibits a thickness difference of less than about 50 nm.

6. The method according to claim 1 , wherein the potentiodynamically measured hysteresis loop in the cyclic voltammetry scan at the current density in the range of 5 to about 10 mA/cm 2 is less than about 30 mV.

7. The method according to claim 6 , wherein, the potentiodynamically measured hysteresis loop in the cyclic voltammetry scan at the current density in the range of 5 to about 10 mA/cm 2 is less than about 20 mV.

8. The method according to claim 7 , wherein the potentiodynamically measured hysteresis loop in the cyclic voltammetry scan at the current density in the range of 5 to about 10 mA/cm 2 is less than about 10 mV.

9. The method according to claim 1 , wherein the current density at which the hysteresis loop is measured is in a range of about 7.5 to about 8.5 mA/cm 2 .

10. The method according to claim 9 , wherein the current density at which the hysteresis loop is measured is about 8 mA/cm 2 .

11. The method according to claim 1 , wherein the plated cobalt deposit also exhibits a potentiodynamically measured hysteresis loop in a cyclic voltammetry scan at a current density in a range of about 1 to less than 5 mA/cm 2 of less than about 90 mV.

12. The method according to claim 11 , wherein the current density at which the hysteresis loop is measured is in a range of about 1.5 to about 2.5 mA/cm 2 .

13. The method according to claim 1 , wherein in the cyclic voltammetry scan, a forward scan represents non-feature area plating and a backward scan represents feature area plating of the cobalt deposit.

14. The method according to claim 1 , wherein the cobalt electrolyte is at least substantially free of an accelerator.

15. The method according to claim 1 , wherein the cobalt electrolyte is at least substantially free of a depolarizer.

16. The method according to claim 1 , wherein the organic additive comprises an acetylenic suppressor.

17. The method according to claim 16 , wherein the acetylenic suppressor comprises a reaction products of an alkoxylated propargyl alcohol or propargyl alcohol with glycidol, propylene oxide, glycidol and propylene oxide, or propylene glycol and glycidol.

18. The method according to claim 17 , wherein the alkoxylated propargyl alcohol is ethoxylated, propargyl alcohol.

19. The method according to claim 1 , wherein the recessed features are damascene features.

20. A method of electrodepositing cobalt onto a substrate comprising recessed features and non-feature areas, wherein the cobalt deposit exhibits a thickness difference across the surface of the substrate of less than about 200 nm the method comprising:
a) receiving the substrate in an electroplating chamber;
b) immersing the substrate into a cobalt electrolyte, the cobalt electrolyte comprising:
(1) a source of cobalt ions;
(2) boric acid;
(3) a pH adjuster; and
(4) an organic additive, wherein the organic additive comprises a suppressor; and

c) electroplating cobalt into the features and onto the non-feature areas for a period of time and under conditions to achieve a level, seam-free, bottom-up fill in the recessed features and plating on the non-feature areas;
wherein the plated cobalt deposit exhibits a potentiodynamically measured hysteresis loop in a cyclic voltammetry scan at a current density in a range of about 1 to less than 5 mA/cm 2 of less than about 90 mV.

21. The method according to claim 20 , wherein the cobalt deposit also exhibits a potentiodynamically measured hysteresis loop in a cyclic voltammetry scan at a current density in a range of 5 to about 10 mA/cm 2 of less than about 50 mV.

Assignees

• Macdermid Enthone Inc

Inventors

• Sun Shaopeng
• Whitten Kyle
• Braye Stephan
• Najjar Elie

Classifications

• H10W20/4437

  the principal metal being a transition metal · CPC title

• H10W20/4403

  based on metals, e.g. alloys, metal silicides (H10W20/4484 takes precedence) · CPC title

• H10W20/056

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

• H10P14/47

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

• Y10T428/24942

  including components having same physical characteristic in differing degree · CPC title