Enhancement of electrolyte hydrodynamics for efficient mass transfer during electroplating

Patent metadata

Field	Value
Publication number	US-9523155-B2
Application number	US-201314103395-A
Country	US
Kind code	B2
Filing date	Dec 11, 2013
Priority date	Dec 12, 2012
Publication date	Dec 20, 2016
Grant date	Dec 20, 2016

Abstract

The embodiments herein relate to methods and apparatus for electroplating one or more materials onto a substrate. In many cases the material is a metal and the substrate is a semiconductor wafer, though the embodiments are no so limited. Typically, the embodiments herein utilize a channeled plate positioned near the substrate, creating a cross flow manifold defined on the bottom by the channeled plate, on the top by the substrate, and on the sides by a cross flow confinement ring. During plating, fluid enters the cross flow manifold both upward through the channels in the channeled plate, and laterally through a cross flow side inlet positioned on one side of the cross flow confinement ring. The flow paths combine in the cross flow manifold and exit at the cross flow exit, which is positioned opposite the cross flow inlet. These combined flow paths result in improved plating uniformity.

First claim

What is claimed is:

1. An electroplating apparatus comprising:
(a) an electroplating chamber configured to contain an electrolyte and an anode while electroplating metal onto a substantially planar substrate;
(b) a substrate holder configured to hold the substantially planar substrate such that a plating face of the substrate is separated from the anode during electroplating;
(c) an ionically resistive element comprising:
(i) a plurality of channels extending through the ionically resistive element and adapted to provide ionic transport through the ionically resistive element during electroplating;
(ii) a substrate-facing side that is substantially parallel to the plating face of the substrate and separated from the plating face of the substrate by a gap; and
(iii) a plurality of protuberances positioned on the substrate-facing side of the ionically resistive element;

(d) an inlet to the gap for introducing cross flowing electrolyte to the gap; and
(e) an outlet to the gap for receiving cross flowing electrolyte flowing in the gap,

wherein the inlet and outlet are positioned proximate azimuthally opposing perimeter locations on the plating face of the substrate during electroplating.

2. The electroplating apparatus of claim 1 , wherein the gap between the substrate-facing side of the ionically resistive element and the plating face of the substrate is less than about 15 mm, as measured between the plating face of the substrate and an ionically resistive element plane.

3. The electroplating apparatus of claim 1 , wherein a gap between the plating face of the substrate and an uppermost height of the protuberances is between about 0.5-4 mm.

4. The electroplating apparatus of claim 1 , wherein the protuberances have a height between about 2-10 mm.

5. The electroplating apparatus of claim 1 , wherein the protuberances are oriented, on average, substantially perpendicular to the direction of cross flowing electrolyte.

6. The electroplating apparatus of claim 1 , wherein at least some of the protuberances have a length to width aspect ratio of at least about 3:1, wherein the protuberance length is oriented in a direction substantially perpendicular to a direction of cross flowing electrolyte between the inlet to the gap and the outlet to the gap, and wherein the protuberance width is oriented in a direction substantially parallel to the direction of cross flowing electrolyte.

7. The electroplating apparatus of claim 1 , wherein at least two different shapes and/or sizes of protuberances are present on the ionically resistive element.

8. The electroplating apparatus of claim 1 , further comprising one or more cutout portions on at least some of the protuberances, through which electrolyte may flow during electroplating.

9. The electroplating apparatus of claim 1 , wherein at least some of the protuberances comprise a face that is substantially normal to an ionically resistive element plane.

10. The electroplating apparatus of claim 1 , wherein at least some of the protuberances comprise a face that is offset from an ionically resistive element plane by a non-right angle.

11. The electroplating apparatus of claim 1 , further comprising a triangular upper portion on at least some of the protuberances.

12. The electroplating apparatus of claim 1 , wherein the protuberances comprise at least a first protuberance segment and a second protuberance segment, and wherein the first and second protuberance segments are offset from the direction of cross flowing electrolyte by angles that are substantially similar but of opposite sign.

13. The electroplating apparatus of claim 1 , wherein the ionically resistive element is configured to shape an electric field and control electrolyte flow characteristics proximate the substrate during electroplating.

14. The electroplating apparatus of claim 1 , further comprising a cross flow injection manifold fluidically coupled to the inlet, wherein the cross flow injection manifold is at least partially defined by a cavity in the ionically resistive element.

15. The electroplating apparatus of claim 1 , further comprising a flow confinement ring positioned over a peripheral portion of the ionically resistive element.

16. The electroplating apparatus of claim 1 , wherein the inlet spans an arc between about 90-180° proximate the perimeter of the plating face of the substrate.

17. The electroplating apparatus of claim 1 , further comprising a plurality of azimuthally distinct segments in the inlet, a plurality of electrolyte feed inlets configured to deliver electrolyte to the plurality of azimuthally distinct inlet segments, and one or more flow control elements configured to independently control a plurality of volumetric flow rates of electrolyte in the plurality of electrolyte feed inlets during electroplating.

18. The electroplating apparatus of claim 1 , wherein the protuberances are substantially coextensive with the plating face of the substrate.

19. The electroplating apparatus of claim 1 , wherein the protuberances are oriented in a plurality of parallel columns, wherein the columns include two or more discontinuous protuberances separated by a non-protuberance gap, and wherein the non-protuberance gaps in adjacent columns are substantially not aligned with one another in the direction of cross flowing electrolyte.

20. A channeled ionically resistive plate for use in an electroplating apparatus to plate material on a semiconductor wafer of standard diameter, comprising:
a plate that is approximately coextensive with a plating face of the semiconductor wafer, wherein the plate has a thickness between about 2-25 mm;
at least about 1000 non-communicating through-holes extending through the thickness of the plate, wherein the through-holes are adapted to provide ionic transport through the plate during electroplating; and
a plurality of protuberances positioned on one side of the plate.

21. A method for electroplating a substrate comprising:
(a) receiving a substantially planar substrate in a substrate holder, wherein a plating face of the substrate is exposed, and wherein the substrate holder is configured to hold the substrate such that the plating face of the substrate is separated from the anode during electroplating;
(b) immersing the substrate in electrolyte, wherein a gap is formed between the plating face of the substrate and an ionically resistive element,
wherein the ionically resistive element is at least about coextensive with the plating face of the substrate,
wherein the ionically resistive element is adapted to provide ionic transport through the ionically resistive element during electroplating, and
wherein the ionically resistive element comprises a plurality of protuberances on a substrate-facing side of the ionically resistive element, the protuberances being substantially coextensive with the plating face of the substrate;

(c) flowing electrolyte in contact with the substrate in the substrate holder (i) from a side inlet, into the gap, and out a side outlet, and (ii) from below the ionically resistive element, through the ionically resistive element, into the gap, and out the side outlet, wherein the side inlet and side outlet are designed or configured to generate cross flowing electrolyte in the gap during electroplating;
(d) rotating the substrate holder; and
(e) electroplating material onto the plating face of the substrate while flowing the electrolyte as in (c).

22. The electroplating apparatus of claim 17

Assignees

• Novellus Systems Inc

Inventors

• Mayer Steven T
• Buckalew Bryan L
• Fu Haiying
• Ponnuswamy Thomas
• Diaz Camilo Hilton
• Rash Robert
• Porter David W

Classifications

• C25D5/08 Primary

  Electroplating with moving electrolyte e.g. jet electroplating {(using locally applied jets of electrolyte C25D5/026)} · CPC title

• C25D21/12 Primary

  Process control or regulation (controlling or regulating in general G05) · CPC title

• C25D17/001

  Apparatus specially adapted for electrolytic coating of wafers, e.g. semiconductors or solar cells · CPC title

• C25D17/002

  Cell separation, e.g. membranes, diaphragms · CPC title

• C25D7/12

  Semiconductors · CPC title