Membrane partition system for plating of wafers

• US 6,569,299 B1
• Filed: 05/18/2000
• Issued: 05/27/2003
• Est. Priority Date: 11/13/1997
• Status: Expired due to Term

• Current Assignee: International Business Machines Corporation, Novellus Systems Incorporated (Lam Research Corporation)
• Original Assignee: International Business Machines Corporation, Novellus Systems Incorporated (Lam Research Corporation)
• Inventors: Dukovic, John Owen, Contolini, Robert J., Reid, Jonathan David
• Primary Examiner(s): Nguyen, Nam
• Assistant Examiner(s): Nicolas, Wesley A.
• Application Number:
  US09/574,666
• Time in Patent Office: 1,104 Days
• Field of Search: 204/282, 204/283, 204/297.11, 204/238, 204/259, 205/148, 205/68
• US Class Current: 204/282
• CPC Class Codes: C25D 17/00 Constructional parts, or assemblies thereof, of cells for electrolytic coating
• CPC Class Codes: C25D 17/001 Apparatus specially adapted for electrolytic coating of wafers, e.g. semiconductors or solar cells
• CPC Class Codes: C25D 17/008 Current shielding devices
• CPC Class Codes: C25D 17/10 Electrodes , e.g. composition, counter electrode

Abstract

An anode includes an anode cup, a membrane and ion source material, the anode cup and membrane forming an enclosure in which the ion source material is located. The anode cup includes a base section having a central aperture and the membrane also has a central aperture. A jet is passed through the central apertures of the base section of the anode cup and through the membrane allowing plating solution to be directed at the center of a wafer being electroplated.

Claims

1. An electroplating system for semiconductor wafers comprising:

a power supply having a negative terminal and a positive terminal;

a semiconductor wafer electrically connected to the negative terminal;

a plating bath holding a plating solution;

an anode positioned in the plating solution and electrically connected to the positive terminal;

a pump for creating a flow of plating solution generally in a direction from the anode towards the wafer; and

a porous membrane positioned downstream from the anode in the flow of plating solution.

2. The electroplating system of claim 1 wherein the anode comprises a plurality of granules.

3. The electroplating system of claim 1 wherein the anode consists essentially of a single piece of material.

4. The electroplating system of claim 1 wherein the anode is a single piece of material.

5. The electroplating system of claim 3 or 4 wherein the anode is in the shape of a disk.

6. The electroplating system of claim 1 wherein the flow of plating solution is generally upward, the porous membrane being positioned above the anode.

7. The electroplating system of claim 1 wherein the porous membrane is fitted against a wall of the plating bath.

8. The electroplating system of claim 1 wherein the membrane has a porosity sufficient to allow ions from the anode to pass through the membrane.

9. The electroplating system of claim 1 wherein the membrane has a porosity sufficient to allow the plating solution to pass through the membrane.

10. The electroplating system of claim 1 wherein the membrane has a porosity sufficient to prevent particulates from the anode greater than one micron in size to pass through the membrane.

11. The electroplating system of claim 1 wherein the porous membrane is disk shaped.

12. The electroplating system of claim 1 wherein the anode comprises a plurality of apertures through which the plating solution passes.

13. The electroplating system of claim 1 comprising a nonconductive shield positioned downstream from the anode in the flow of plating solution, the shield comprising an annular member with an aperture having a diameter less than a diameter of the anode.

14. The electroplating system of claim 13 wherein the diameter of the aperture of the shield is less than a diameter of the wafer.