Enhanced plating bath and additive chemistries for cobalt plating

Patent metadata

Field	Value
Publication number	US-10487410-B2
Application number	US-201715419430-A
Country	US
Kind code	B2
Filing date	Jan 30, 2017
Priority date	Feb 26, 2016
Publication date	Nov 26, 2019
Grant date	Nov 26, 2019

Abstract

Implementations of the disclosure may include methods of electroplating features formed on a semiconductor device, such as the trenches and vias formed by single or dual Damascene processes using a cobalt plating bath. The cobalt electroplating bath may contain “additive packages” or “additive systems” that include a combination of additives in certain ratios that facilitate the metal filling of high aspect ratio sub-micrometer features. Implementations of the disclosure provide new cobalt plating bath methods and chemistries and that include alkyl modified imidazoles, imidazolines, and imidazolidines suppressor compounds.

First claim

What is claimed is:

1. A method of forming a cobalt layer on a substrate, comprising:
immersing a substrate having a conductive layer disposed thereon in a cobalt plating bath, wherein the cobalt plating bath comprises:
a first amount of a cobalt ion; and
a first amount of at least one suppressor compound comprising an imidazole, imidazoline, or imidazolidine group, and wherein the imidazole, imidazoline, or imidazolidine group comprises an alkyl group; and

biasing the conductive layer relative to an anode that is in electrical communication with the cobalt plating bath and the conductive layer to form a cobalt layer on a surface of the conductive layer, wherein the alkyl group is an oligomeric or polymeric polyethylene glycol group.

2. The method of claim 1 , wherein the polyethylene glycol group is of a molecular weight from between about 100 g/mole to about 30,000 g/mole.

3. The method of claim 1 , wherein the cobalt plating bath has a pH of between about 5 and about 7.

4. The method of claim 1 , wherein the first amount of the cobalt ion is introduced into the cobalt plating bath in the form of a cobalt sulfamate solution or a cobalt glycine complex containing solution, wherein a concentration of the cobalt ion in the cobalt plating bath is between about 0.001 moles/L and 0.25 moles/L.

5. The method of claim 4 , wherein the first amount of the cobalt ion is introduced into the cobalt plating bath in the form of the cobalt sulfamate solution.

6. The method of claim 1 , wherein the cobalt plating bath further comprises a first amount of boric acid.

7. The method of claim 1 , wherein the imidazole, imidazoline, or imidazolidine group comprising the polyethylene glycol group has the structure:

wherein “n” is an integer and a molecular weight of the polyethylene glycol group is from between about 250 g/mole to about 30,000 g/mole.

8. The method of claim 1 , wherein the imidazole, imidazoline, or imidazolidine group comprising the polyethylene glycol group has the structure:

wherein the R group comprises the polyethylene glycol group.

9. The method of claim 1 , wherein the imidazole, imidazoline, or imidazolidine group comprising the polyethylene glycol group has the structure:

wherein the R group comprises the polyethylene glycol group.

10. The method of claim 1 , wherein the imidazole, imidazoline, or imidazolidine group comprising the polyethylene glycol group has the structure:

wherein the R group comprises the polyethylene glycol group.

11. A method of forming a cobalt layer on a substrate, comprising:
immersing a substrate in a cobalt plating bath having a pH of at least 5 , wherein the substrate has a feature coated with a conductive seed layer and the cobalt plating bath comprises:
a first amount of a cobalt ion;
a first amount of at least one accelerator compound; and
a first amount of at least one suppressor compound comprising an imidazole, imidazoline, or imidazolidine group, and wherein the imidazole, imidazoline, or imidazolidine group comprises an alkyl group; and

biasing the conductive seed layer relative to an anode that is in electrical communication with the cobalt plating bath and the conductive seed layer to form a cobalt layer on a surface of the conductive seed layer, wherein the alkyl group is a polyethylene glycol group.

12. The method of claim 11 , wherein the conductive seed layer comprises a material selected from cobalt, copper, manganese, doped copper, ruthenium, or a combination thereof.

13. The method of claim 12 , wherein the feature is a trench having an opening of 30 nanometers or less.

14. The method of claim 11 , wherein the first amount of the cobalt ion is from between about 0.001 moles/L and about 0.25 moles/L and the first amount of the suppressor compound is from between about 10 parts per million and about 1000 parts per million.

15. The method of claim 14 , wherein the cobalt plating bath further comprises a first amount of boric acid.

16. The method of claim 11 , wherein the imidazole, imidazoline, or imidazolidine group comprising the polyethylene glycol group has the structure:

wherein “n” is an integer and the molecular weight of the polyethylene glycol group is from between about 250 grams/mole to about 30,000 grams/mole.

17. The method of claim 11 , wherein the imidazole, imidazoline, or imidazolidine group comprising the polyethylene glycol group has the structure:

wherein the R group comprises the polyethylene glycol group.

18. The method of claim 11 , wherein the imidazole, imidazoline, or imidazolidine group comprising the polyethylene glycol group has the structure:

wherein the R group comprises the polyethylene glycol group.

19. The method of claim 11 , wherein the imidazole, imidazoline, or imidazolidine group comprising the polyethylene glycol group has the structure:

wherein the R group comprises the polyethylene glycol group.

Assignees

• Applied Materials Inc

Inventors

• Emesh Ismail
• Shaviv Roey
• Pabelico Chris

Classifications

• H10W20/031

  of conductive parts of the interconnections · CPC title

• H10W20/051

  by ion implantation · CPC title

• H10W20/084 Primary

  for dual-damascene structures · CPC title

• C25D7/123

  Semiconductors first coated with a seed layer or a conductive layer · CPC title

• C25D3/18 Primary

  Heterocyclic compounds · CPC title