Wetting pretreatment for enhanced damascene metal filling

Patent metadata

Field	Value
Publication number	US-9852913-B2
Application number	US-201514593676-A
Country	US
Kind code	B2
Filing date	Jan 9, 2015
Priority date	Jun 17, 2009
Publication date	Dec 26, 2017
Grant date	Dec 26, 2017

Abstract

Disclosed are pre-wetting apparatus designs and methods. These apparatus designs and methods are used to pre-wet a wafer prior to plating a metal on the surface of the wafer. Disclosed compositions of the pre-wetting fluid prevent corrosion of a seed layer on the wafer and also improve the filling rates of features on the wafer.

First claim

What is claimed is:

1. A method of electroplating a layer of copper on a wafer substrate, the method comprising:
(a) providing the wafer substrate having an exposed metal layer on at least a portion of its surface to a pre-wetting process chamber;
(b) contacting the wafer substrate with a pre-wetting fluid under subatmospheric pressure, the pre-wetting fluid comprising water and copper ions, to form a layer of pre-wetting fluid on the wafer substrate;
(c) contacting the pre-wetted wafer substrate with a plating solution, the plating solution comprising copper ions, cathodically biasing the wafer substrate and electroplating a layer of copper on the wafer substrate, wherein the concentration of copper ions in the pre-wetting fluid is greater than the concentration of copper ions in the plating solution.

2. The method of claim 1 , wherein the pre-wetting fluid is substantially free of additives selected from the group consisting of halides, accelerators, and levelers.

3. The method of claim 1 , wherein the pre-wetting fluid contains polyethylene oxide at a concentration of less than about 15 ppm.

4. The method of claim 1 , wherein the plating solution contains an additive selected from the group consisting of halides, accelerators, levelers, and suppressors.

5. The method of claim 1 , wherein the layer of pre-wetting fluid has a thickness of between about 50-500 μm immediately before contact with the plating solution.

6. The method of claim 1 , wherein the copper ions in the pre-wetting fluid are from a copper salt, wherein the concentration of the copper salt in the pre-wetting fluid is at least about 50% of the saturation limit of the copper salt.

7. The method of claim 1 , wherein the pre-wetting fluid has a copper ion concentration of greater than about 20 g/L.

8. The method of claim 1 , wherein the pre-wetting fluid consists essentially of the water and a copper salt, wherein the copper salt is a source of the copper ions in the pre-wetting fluid.

9. The method of claim 1 , wherein the concentration of the copper ions in the pre-wetting fluid is at least about 25% greater than the concentration of the copper ions in the plating solution.

10. The method of claim 1 , wherein the copper ions in the pre-wetting fluid are from a dissolved copper sulfate and/or copper methanesulfonate.

11. The method of claim 1 , wherein the wafer substrate provided in (a) comprises a plurality of recessed features.

Assignees

• Novellus Systems Inc

Inventors

• Mayer Steven T
• Porter David W
• Willey Mark J

Classifications

• H10W20/023

  the interconnections being through-semiconductor vias · CPC title

• H10W20/052

  by treatments not introducing additional elements therein · CPC title

• H10P14/47 Primary

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

• C25D21/04

  Removal of gases or vapours {; Gas or pressure control} · CPC title

• C25D5/02

  Electroplating of selected surface areas · CPC title