Apparatus and method for modulating azimuthal uniformity in electroplating

Patent metadata

Field	Value
Publication number	US-2016362809-A1
Application number	US-201514734882-A
Country	US
Kind code	A1
Filing date	Jun 9, 2015
Priority date	Jun 9, 2015
Publication date	Dec 15, 2016
Grant date	—

Abstract

An apparatus for electroplating metal on a semiconductor substrate with improved azimuthal uniformity includes in one aspect: a plating chamber configured to contain an electrolyte and an anode; a substrate holder configured to hold the semiconductor substrate; an ionically resistive ionically permeable element (“the element”) configured to be positioned proximate the substrate; and a shield configured for providing azimuthally asymmetrical shielding and positioned between the substrate holder and the element such that the closest distance between the substrate-facing surface of the shield and the working surface of the substrate is less than 2 mm. In some embodiments there is an electrolyte-filled gap between the substrate-facing surface of the element and the shield during electroplating. The substrate-facing surface of the shield may be contoured such that the distance from different positions of the shield to the substrate is varied.

First claim

1 . An electroplating apparatus comprising:
(a) a plating chamber configured to contain an electrolyte and an anode while electroplating metal onto a semiconductor substrate; (b) a substrate holder configured to hold the semiconductor substrate during electroplating; (c) an ionically resistive ionically permeable element comprising a substrate-facing surface and an opposing surface, wherein the element allows for flow of ionic current through the element towards the substrate during electroplating, wherein the ionically resistive ionically permeable element comprises a plurality of non-communicating channels, and wherein the ionically resistive ionically permeable element is positioned such that a closest distance between the substrate-facing surface of the element and a working surface of the substrate is about 10 mm or less; and (d) a shield, configured for providing azimuthally asymmetric shielding, wherein the shield has a substrate-facing surface and an opposing surface, wherein the shield is positioned such that the closest distance between the substrate-facing surface of the shield and the working surface of the substrate is less than about 2 mm.

2 . The electroplating apparatus of claim 1 , wherein the closest distance between the substrate-facing surface of the shield and the working surface of the substrate is about 0.5 mm-1.5 mm.

3 . The electroplating apparatus of claim 1 , wherein the substrate-facing surface of the shield is contoured such that a distance from the substrate-facing surface of the shield to the working surface of the substrate is varied.

4 . The electroplating apparatus of claim 1 , wherein the substrate-facing surface of the shield is contoured such that a distance from the substrate-facing surface of the shield to the working surface of the substrate is varied radially for a selected azimuthal position.

5 . The electroplating apparatus of claim 1 , wherein the substrate-facing surface of the shield is contoured such that a distance from the substrate-facing surface of the shield to the working surface of the substrate at a first radial position is greater than at a second radial position, wherein the second radial position is greater than the first radial position.

6 . The electroplating apparatus of claim 1 , wherein the substrate-facing surface of the shield is contoured such that a distance from the substrate-facing surface of the shield to the working surface of the substrate gradually decreases in a radial direction as the radial position increases at least for a portion of the shield.

7 . The electroplating apparatus of claim 1 , wherein the opposite surface of the shield contacts the ionically resistive ionically permeable element and blocks a portion of the channels on the substrate-facing surface of the element.

8 . The electroplating apparatus of claim 1 , wherein the shield has one or more electrolyte-permeable openings.

9 . The electroplating apparatus of claim 1 , wherein the shield is generally wedge-shaped.

10 . The electroplating apparatus of claim 1 , wherein the shield is generally wedge-shaped and has a central wedge angle of between about 100-180°, located at a radial distance of between about 10-40 mm from a radial position of an edge of the substrate.

11 . The electroplating apparatus of claim 1 , wherein the ionically resistive ionically permeable element is positioned such that the distance between the substrate-facing surface of the element and the substrate is between about 2-10 mm during electroplating, and wherein the shield is positioned such that the smallest distance between the substrate-facing surface of the shield and the working surface of the substrate is about 1.5 mm or less during electroplating.

12 . The electroplating apparatus of claim 1 , wherein the shield is positioned such that there is an electrolyte-filled gap between the substrate-facing surface of the ionically resistive ionically permeable element and the shield during electroplating.

13 . The electroplating apparatus of claim 12 , wherein at least a portion of the non-communicating channels falling into a projection of the shield are blocked to ionic current flow.

14 . The electroplating apparatus of claim 12 , wherein at least a portion of the non-communicating channels falling into a projection of the shield are blocked by a second shield contacting the opposing surface of the ionically resistive ionically permeable element.

15 . The electroplating apparatus of claim 12 , wherein at least a portion of the ionically resistive ionically permeable element falling into a projection of the shield has no channels.

16 . The electroplating apparatus of claim 12 , further comprising an inlet to a microchamber between the substrate and the ionically resistive ionically permeable element for introducing electrolyte flowing to the microchamber and an outlet to the microchamber for receiving electrolyte flowing through the microchamber, wherein the inlet and the outlet are positioned proximate azimuthally opposing perimeter locations of the working face of the substrate, and wherein the inlet and outlet are adapted to generate cross-flow of electrolyte in the micro chamber.

17 . The electroplating apparatus of claim 12 , wherein the apparatus is configured for generating electrolyte cross-flow through the gap between the ionically resistive ionically permeable element and the shield.

18 . The electroplating apparatus of claim 12 , wherein the gap between the ionically resistive ionically permeable element and the shield is between about 0.5-5 mm.

Assignees

• Lam Res Corp

Inventors

• Graham Gabriel Hay
• Chua Lee Peng
• Mayer Steven T
• Rash Robert
• Berke Aaron

Classifications

• C25D17/001 Primary

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

• C25D7/123

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

• C25D17/007

  Current directing devices · CPC title

• C25D5/04

  Electroplating with moving electrodes · CPC title

• C25D5/02

  Electroplating of selected surface areas · CPC title