Wetting pretreatment for enhanced damascene metal filling

Patent metadata

Field	Value
Publication number	US-10840101-B2
Application number	US-201715818329-A
Country	US
Kind code	B2
Filing date	Nov 20, 2017
Priority date	Jun 17, 2009
Publication date	Nov 17, 2020
Grant date	Nov 17, 2020

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 metal on a wafer substrate, the method comprising:
(a) providing the wafer substrate having an exposed metal layer on at least a portion of a surface of the wafer substrate to a pre-wetting process chamber;
(b) reducing pressure in the pre-wetting process chamber to a subatmospheric pressure;
(c) contacting the wafer substrate, at a subatmospheric pressure, with a pre-wetting fluid comprising an acid to at least partially remove surface oxide from the exposed metal layer and to form a layer of pre-wetting fluid on the wafer substrate, wherein the pre-wetting fluid has an acidic pH; and
(d) contacting the pre-wetted wafer substrate with a plating solution comprising metal ions to electroplate a layer of metal by electrochemically reducing the metal ions on the wafer substrate, wherein the plating solution has an acidic pH and wherein the pre-wetting fluid does not contain the metal ions that are contained in the plating solution.

2. The method of claim 1 , wherein the metal ions in the plating solution are copper ions and the layer of metal electroplated in (d) is a layer of copper.

3. The method of claim 1 , wherein the pH of the pre-wetting fluid is between about 2-6.

4. The method of claim 1 , wherein the acid in the pre-wetting fluid is selected from the group consisting of sulfuric acid, methanesulfonic acid, and acetic acid.

5. The method of claim 1 , wherein (c) and (d) are performed in different chambers.

6. The method of claim 1 , wherein the surface oxide is a copper oxide.

7. The method of claim 1 , wherein the pH of the pre-wetting fluid is between about 2-4.

8. The method of claim 1 , wherein the pH of the pre-wetting fluid is at least about 2.

9. The method of claim 1 , wherein the pH of the pre-wetting fluid is about 2.

10. The method of claim 1 , wherein the pre-wetting fluid further comprises metal ions.

11. The method of claim 1 , wherein the acid in the pre-wetting fluid is sulfuric acid.

12. The method of claim 1 , wherein the pre-wetting fluid further comprises an electroplating suppressor.

13. The method of claim 1 , wherein the acid in the pre-wetting fluid is sulfuric acid or methanesulfonic acid, and wherein a concentration of the acid is less than about 2 g/L.

14. The method of claim 1 , wherein the pre-wetting fluid is substantially free of halides, and the plating solution further comprises a halide.

15. The method of claim 1 , wherein the pre-wetting fluid is substantially free of electroplating accelerators, and the plating solution further comprises an electroplating accelerator.

16. The method of claim 1 , wherein (d) is performed in a plating chamber that is different from the pre-wetting process chamber, and wherein the method further comprises: after (c), transferring the wafer substrate from the pre-wetting process chamber to the plating chamber.

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

• H10P90/12

  Preparing bulk and homogeneous wafers · CPC title

• H10P14/40 Primary

  of conductive or resistive materials · CPC title