Methods for forming cobalt interconnects

Patent metadata

Field	Value
Publication number	US-2016309596-A1
Application number	US-201514687755-A
Country	US
Kind code	A1
Filing date	Apr 15, 2015
Priority date	Apr 15, 2015
Publication date	Oct 20, 2016
Grant date	—

Abstract

A method for depositing metal in a feature on a workpiece includes forming a seed layer in a feature on a workpiece, wherein the seed layer includes a metal selected from the group consisting of cobalt and nickel; electrochemically depositing a first metallization layer on the seed layer, wherein electrochemically depositing the metallization layer includes using a plating electrolyte having a plating metal ion and a pH in the range of 6 to 13; and heat treating the workpiece after deposition of the first metallization layer.

First claim

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1 . A method for depositing metal in a feature on a workpiece, the method comprising:
(a) forming a seed layer in a feature on a workpiece, wherein the seed layer includes a metal selected from the group consisting of cobalt and nickel; (b) electrochemically depositing a first metallization layer on the seed layer, wherein electrochemically depositing the metallization layer includes using a plating electrolyte having a plating metal ion and a pH in the range of 6 to 13; and (c) heat treating the workpiece after deposition of the first metallization layer.

2 . The method of claim 1 , wherein the plating metal ion is selected from the group consisting of cobalt, nickel, and copper.

3 . The method of claim 1 , further comprising depositing at least two features on a workpiece having two different sizes, wherein the seed layer fills the smallest feature, but does not fill the largest feature.

4 . The method of claim 1 , further comprising depositing at least two features on a workpiece having two different sizes, wherein the seed layer does not fill either feature.

5 . The method of claim 1 , wherein the temperature for heat treating the workpiece is in the temperature range of 150 degrees C. to 400 degrees C.

6 . The method of claim 1 , wherein heat treating the workpiece anneals the seed and first metallization layers.

7 . The method of claim 1 , wherein heat treating the workpiece reflows at least one of the seed and first metallization layers at least partially fill the feature.

8 . The method of claim 1 , further comprising plasma treating the seed layer using a hydrogen radical H*.

9 . The method of claim 1 , further comprising heat treating the seed layer before depositing the first metallization layer.

10 . The method of claim 9 , wherein heat treating the seed layer is in the temperature range of 200 degrees C. to 400 degrees C.

11 . The method of claim 9 , wherein heat treating the seed layer anneals the seed layer.

12 . The method of claim 9 , wherein heat treating the seed layer reflows the seed layer to at least partially fill the feature.

13 . The method of claim 1 , wherein the first metallization layer is a conformal or superconformal conductive layer.

14 . The method of claim 1 , wherein the first metallization layer includes an overburden.

15 . The method of claim 1 , wherein the first metallization layer fills the largest features without depositing an overburden on the workpiece.

16 . The method of claim 1 , further comprising electrochemically depositing a second metallization layer on the first metallization layer.

17 . The method of claim 16 , wherein the second metallization layer is an overburden, a cap, a fill layer, a conformal conductive layer, or a superconformal conductive layer.

18 . The method of claim 16 , wherein the second metallization layer is not subjected to heat treatment.

19 . The method of claim 1 , further comprising CMP.

20 . The method of claim 1 , further comprising heat treating the workpiece after CMP.

21 . The method of claim 1 , wherein the seed layer has a sheet resistance selected from the group consisting of greater than about 10 Ohm/sq., greater than about 50 Ohm/sq., and greater than about 100 Ohm/sq.

22 . The method of claim 1 , wherein the seed layer is deposited by a process selected from the group consisting of physical vapor deposition, chemical vapor deposition, atomic layer deposition, and electro-less deposition.

23 . The method of claim 1 , wherein the workpiece includes an adhesion or barrier layer deposited in the feature prior to deposition of the seed layer.

24 . The method of claim 1 , wherein workpiece includes a cobalt seed layer deposited directly on a dielectric layer.

25 . The method of claim 1 , wherein the critical dimension of the smallest feature is less than 30 nm

26 . The method of claim 1 , wherein electrical contacts to the workpiece for making an electrical connection with the workpiece in the electrochemical deposition process are at least partially immersed in the deposition electrolyte.

27 . The method of claim 26 , wherein the electrical contacts are selected from the group consisting of open contacts, unsealed contacts, embedded contacts, and shielded contacts.

28 . The method of claim 1 , wherein the first metallization layer is deposited over the entire surface of the seed layer.

29 . A microfeature workpiece, comprising:
a dielectric having a feature, wherein the critical dimension of the feature is less than 30 nm; a bulk metallization layer in the feature having no detectable interface between an electrochemically deposited film and a seed film, wherein the bulk metallization layer includes cobalt or nickel.

Assignees

• Applied Materials Inc

Inventors

• Shaviv Roey
• Lam John W
• Bochman Timothy
• Tseng Jennifer Meng Chu

Classifications

• H10W20/4437

  the principal metal being a transition metal · CPC title

• C25D5/50

  by heat-treatment · CPC title

• C25D3/12

  of nickel or cobalt · CPC title

• C25D7/123 Primary

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

• H10P14/47

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