Dynamic modulation of cross flow manifold during electroplating

Patent metadata

Field	Value
Publication number	US-10233556-B2
Application number	US-201615161081-A
Country	US
Kind code	B2
Filing date	May 20, 2016
Priority date	Jul 2, 2010
Publication date	Mar 19, 2019
Grant date	Mar 19, 2019

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. Also typically present is an edge flow element configured to direct electrolyte into a corner formed between the substrate and substrate holder. 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 and the edge flow element result in improved plating uniformity, especially at the periphery of the substrate.

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 substrate, the substrate being substantially planar;
(b) a substrate holder configured to hold the substrate such that a plating face of the substrate is separated from the anode during electroplating;
(c) an ionically resistive element including a substrate-facing surface, wherein the ionically resistive element is at least coextensive with the plating face of the substrate during electroplating, the ionically resistive element adapted to provide ionic transport through the element during electroplating;
(d) a cross flow manifold defined between the plating face of the substrate and the substrate-facing surface of the ionically resistive element, the cross flow manifold having an average height of about 15 mm or less;
(e) an inlet to the cross flow manifold for introducing electrolyte to the cross flow manifold;
(f) an outlet to the cross flow manifold for receiving electrolyte flowing in the cross flow manifold; and
(g) a controller configured to modulate a height of the cross flow manifold during electroplating, wherein the controller is configured to modulate the height of the cross flow manifold during an initial portion of an electroplating process and to maintain the height of the cross flow manifold static during a later portion of the electroplating process, wherein during the later portion of the electroplating process, recessed features on the substrate are on average at least about 50% filled.

2. The electroplating apparatus of claim 1 , wherein the inlet and outlet are positioned proximate azimuthally opposing perimeter locations on the plating face of the substrate during electroplating, and wherein the inlet and outlet are adapted to generate cross-flowing electrolyte in the cross flow manifold to create or maintain a shearing force on the plating face of the substrate during electroplating.

3. The electroplating apparatus of claim 1 , wherein the controller is configured to modulate the height of the cross flow manifold during electroplating at a frequency between about 1-10 Hz.

4. The electroplating apparatus of claim 3 , wherein the frequency is between about 3-8 Hz.

5. The electroplating apparatus of claim 1 , wherein the height of the cross flow manifold is modulated by a distance between about 0.1-10 mm.

6. The electroplating apparatus of claim 5 , wherein the height of the cross flow manifold is modulated by a distance between about 0.5-5 mm.

7. The electroplating apparatus of claim 1 , wherein the height of the cross flow manifold is modulated by varying the position of the substrate.

8. The electroplating apparatus of claim 1 , wherein the height of the cross flow manifold is modulated by varying the position of the ionically resistive element while maintaining the electroplating chamber stationary.

9. The electroplating apparatus of claim 1 , wherein the height of the cross flow manifold is modulated by varying the position of the electroplating chamber.

10. The electroplating apparatus of claim 1 , wherein the controller is configured to modulate the height of the cross flow manifold such that a maximum rate at which the height of the cross flow manifold increases is the same as a maximum rate at which the height of the cross flow manifold decreases.

11. The electroplating apparatus of claim 1 , wherein the controller is configured to modulate the height of the cross flow manifold such that a maximum rate at which the height of the cross flow manifold increases differs from a maximum rate at which the height of the cross flow manifold decreases.

12. The electroplating apparatus of claim 11 , wherein the maximum rate at which the height of the cross flow manifold decreases is greater than the maximum rate at which the height of the cross flow manifold increases.

13. The electroplating apparatus of claim 1 , wherein the height of the cross flow manifold remains below about 5 mm during electroplating.

14. The electroplating apparatus of claim 1 , wherein the ionically resistive element further comprises a plurality of protuberances oriented, on average, perpendicular to a direction of cross-flowing electrolyte in the cross flow manifold.

15. The electroplating apparatus of claim 14 , wherein the protuberances are linear protuberances oriented such that the length of each protuberance is perpendicular to the direction of cross-flowing electrolyte in the cross flow manifold.

16. The electroplating apparatus of claim 15 , wherein the protuberances have a length to width aspect ratio of at least about 3:1.

17. The electroplating apparatus of claim 1 , wherein when the substrate is positioned in the substrate holder, a corner forms at the interface between the substrate and the substrate holder, the corner defined on top by the plating face of the substrate and on the side by the substrate holder, the electroplating apparatus further comprising an edge flow element configured to direct electrolyte into the corner at the interface between the substrate and the substrate holder, the edge flow element being arc-shaped or ring-shaped and positioned proximate a periphery of the substrate and at least partially radially inside of the corner at the interface between the substrate and the substrate holder.

18. The electroplating apparatus of claim 17 , wherein the edge flow element is configured to attach to the ionically resistive element and/or to the substrate holder.

19. A method for electroplating a substrate comprising:
(a) receiving a substrate in a substrate holder, the substrate being substantially planar, 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 an anode during electroplating;
(b) immersing the substrate in electrolyte, wherein a cross flow manifold is formed between the plating face of the substrate and a substrate-facing surface of an ionically resistive element, the cross flow manifold having an average height of about 15 mm or less, wherein the ionically resistive element is at least coextensive with the plating face of the substrate, and wherein the ionically resistive element is adapted to provide ionic transport through the ionically resistive element during electroplating;
(c) flowing electrolyte in contact with the substrate in the substrate holder from below the ionically resistive element, through the ionically resistive element, into the cross flow manifold, and out a side outlet;
(d) rotating the substrate holder; and
(e) modulating a height of the cross flow manifold and electroplating material onto the plating face of the substrate while flowing the electrolyte as in (c), wherein the height of the cross flow manifold is modulated during an initial portion of the electroplating process and is maintained static during a later portion of the electroplating process, where during the later portion of the electroplating process, recessed features on the substrate are on average at least about 50% filled.

Assignees

• Lam Res Corp

Inventors

• Graham Gabriel Hay
• Hiester Jacob Lee
• Chua Lee Peng
• Buckalew Bryan L

Classifications

• C25D7/12

  Semiconductors · CPC title

• C25D17/001 Primary

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

• C25D21/12

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

• C25D5/18 Primary

  Electroplating using modulated, pulsed or reversing current · CPC title

• C25D5/08

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