Cylindrical cathode for magnetically-enhanced sputtering

• US 4,376,025 A
• Filed: 06/14/1982
• Issued: 03/08/1983
• Est. Priority Date: 06/14/1982
• Status: Expired due to Fees

• Current Assignee: The Dow Chemical Company (Dow, Inc.), Jackson Tube Service, Inc.
• Original Assignee: Battelle Development Corporation
• Inventors: Zega, Bogdan
• Primary Examiner(s): Demers, Arthur P.
• Application Number:
  US06/388,482
• Time in Patent Office: 267 Days
• Field of Search: 204/192 R, 204/298
• US Class Current: 204/192.12
• CPC Class Codes: H01J 37/3402 using supplementary magnetic fields

Abstract

In this cylindrical, magnetically-enhanced, sputtering cathode, the magnetic field at the cathode target is generated by applying an electric current through a hollow electrical conductor disposed within a tubular target, so that the electric current flowing along this conductor induces circular magnetic lines concentrically around its axis. By biasing negatively the tubular target immersed in a low pressure gas, a glow discharge is generated. Electrons, emitted from the target surface are accelerated radially by the electric field, but deviated perpendicularly by the magnetic field. The resulting motion is confined in a spirally-shaped area centered on the conductor axis.

Claims

1. A cylindrical, magnetically-enhanced, sputtering cathode which produces a thin film on the surface of an object, which comprises:

a tubular target;

a hollow electrical conductor disposed within the tubular target;

means for applying an electric current through the conductor which generates a magnetic field around the tubular target; and

means for circulating a liquid coolant through the electrical conductor.

2. The cylindrical, magnetically-enhanced, sputtering cathode as recited in claim 1 wherein the ends of the electrical conductor are connected to a low voltage, current source isolated from ground.

3. A sputtering apparatus utilizing the cylindrical, magnetically-enhanced, sputtering cathode as recited in claim 2 further comprising a d.c. high voltage supply source having its negative terminal connected to the low voltage current source.

4. The cylindrical, magnetically-enhanced, sputtering cathode as recited in claim 2 wherein the low voltage current source is an a.c. source.

5. The cylindrical, magnetically-enhanced, sputtering cathode as recited in claim 1, further comprising an annular tight chamber provided between the tubular target and the electrical conductor, the annular tight chamber being connected to a pressurized gas coolant source.

6. A method of producing a thin film onto a substrate within a cylindrical, magnetically-enhanced, cathodic sputtering apparatus, which comprises:

providing a hollow electrical conductor disposed within a tubular target and at least one anode located outside the tubular conductor;

circulating a liquid coolant through the electrical conductor;

applying an electric current through the conductor which generates a magnetic field around the tubular target; and

generating a glow discharge between the tubular target and the anode.

7. The method of producing a thin film onto a substrate as recited in claim 6, wherein the anode is the substrate.

8. The method of producing a thin film onto a substrate as recited in claim 6, wherein the electric current applied through the conductor is a low voltage alternating current.

9. The method of producing a thin film onto a substrate as recited in claim 6, wherein the electric current that is applied through the conductor is a direct current.