Remote plasma source generating a disc-shaped plasma

• US 8,884,525 B2
• Filed: 03/20/2012
• Issued: 11/11/2014
• Est. Priority Date: 03/22/2011
• Status: Active Grant

• Current Assignee: AES Global Holdings Pte Ltd. (Advanced Energy Industries, Inc. (China))
• Original Assignee: Advanced Energy Industries Incorporated
• Inventors: Hoffman, Daniel J., Carter, Daniel, Grilley, Randy, Peterson, Karen
• Primary Examiner(s): Tan, Vibol
• Application Number:
  US13/425,159
• Publication Number:
  US 20120242229A1
• Time in Patent Office: 966 Days
• Field of Search: 315/111.21, 315/111.41, 315/111.51, 315/111.71, 315/111.91, 219/121.4, 219/121.41, 219/121.43, 219/121.52, 219/121.54, 219/121.57
• US Class Current: 315/111.21
• CPC Class Codes: H05H 1/46 using applied electromagnetic fields, e.g. high frequency or microwave energy H05H1/26 takes precedence
• CPC Class Codes: H05H 1/4652 using inductive coupling means, e.g. coils

Abstract

Disclosed herein are systems, methods and apparatuses for dissociating a non-activated gas through a disc-shaped plasma in a remote plasma source. Two inductive elements, one on either side of the disc-shaped plasma, generate a magnetic field that induces electric fields that sustain the disc-shaped plasma. The inductive elements can be coiled conductors having any number of loops and can be arranged in planar or vertical coils or a combination of planar and vertical coils. Additionally, the ratio of inductive element radius to gap distance between the two inductive elements can be configured to achieve a desired vertical plasma confinement.

Claims

1. A remote plasma source comprising:

a first inductive coil having a first plurality of loops, the first plurality of loops having an average radius R1;

a second inductive coil having a second plurality of loops, the second plurality of loops having the average radius R1,

wherein the first and second inductive coils are parallel to each other and separated by a distance D,

wherein the first and second inductive coils are configured to conduct an alternating current to generate magnetic fields that sustain a disc-shaped plasma between the first and second inductive coils, wherein the alternating current sustains the disc-shaped plasma primarily through inductive coupling;

a chamber disposed between the first and second inductive coils, and configured to enclose the disc-shaped plasma;

a first dielectric layer parallel to the first and second inductive coils and disposed between the chamber and the first inductive coil,

wherein the first dielectric layer is configured to reduce capacitive coupling between the first inductive coil and the disc-shaped plasma and allow the magnetic fields to pass from the first inductive coil to the disc-shaped plasma; and

a second dielectric layer parallel to the first and second inductive coils and arranged between the chamber and the second inductive coil,

wherein the second dielectric layer is configured to reduce capacitive coupling between the second inductive coil and the disc-shaped plasma and allow the magnetic fields to pass from the second inductive coil to the disc-shaped plasma;

a gas entry connected to the chamber and configured to provide non-activated gas to the chamber; and

a gas exit connected to the chamber and configured to enable activated gas and free radicals to exit the chamber.

2. The system of claim 1, wherein the first and second inductive coils are solenoid-shaped inductors.

3. The system of claim 1, wherein the first and second inductive coils are planar inductors.

4. The system of claim 1, wherein the first and second inductive coils comprise two or more windings stacked vertically like a solenoid and two or more windings arranged in a planar dimension.

5. The system of claim 1, wherein the gas entry is arranged to provide the non-activated gas in a direction parallel to the first and second inductive coils and intersecting a portion of the disc-shaped plasma.

6. The system of claim 1, wherein the disc-shaped plasma has a plasma density that increases towards a center of the chamber.

7. A method comprising:

providing a reactive gas to a remote plasma source chamber through a gas entry connected to the chamber that is configured to provide reactive gas to the chamber;

passing a high voltage current through a first inductor and a second inductor to generate an electric field passing from the first inductor through a first dielectric layer, through the remote plasma source chamber, through a second dielectric layer, and to the second inductor,

wherein the electric field is strong enough to ignite a plasma in the reactive gas in the remote plasma source chamber;

passing an alternating current through the first inductor and the second inductor to inductively induce mirror electric fields in the plasma,

wherein the induced mirror electric fields propagate in an opposite direction to the alternating current, and wherein the induced mirror electric fields sustain the plasma; and

dissociating the reactive gas by passing it through the plasma to form activated gas and free radicals; and

removing the activated gas and free radicals from the remote plasma source chamber through a gas exit connected to the chamber that is configured to enable the activated gas and free radicals to exit through the chamber.

8. The method of claim 7, further comprising directing an alternating magnetic field between the first and second inductors in a direction perpendicular to a first inner surface and a second inner surface of the remote plasma chamber.

9. The method of claim 7, wherein the alternating magnetic field has an equivalent field density at the first and second inner surfaces of the remote plasma chamber.

10. A system comprising:

a remote plasma source chamber having parallel first and second surfaces;

a first coiled conductor arranged outside the remote plasma source chamber and adjacent to the first surface of the remote plasma source chamber, wherein the first coiled conductor generates a first magnetic field directed into the remote plasma source chamber and primarily in a first direction perpendicular to the first and second surfaces;

a first dielectric arranged between the first surface and the first coiled conductor;

a second coiled conductor arranged outside the remote plasma source chamber and adjacent to the second surface of the remote plasma source chamber, wherein the second coiled conductor generates a second magnetic field primarily in the first direction;

a second dielectric arranged between the second surface and the second coiled conductor;

a reactive gas entry that directs a reactive gas into the remote plasma source chamber in a second direction tangential to an outermost portion of the first coiled conductor and perpendicular to the first direction; and

a radicals exit port that removes radicals formed when the reactive gas is passed through a plasma disc formed in the remote plasma source chamber.