Dipole ring magnet assisted microwave radial line slot antenna plasma processing method and apparatus

Patent metadata

Field	Value
Publication number	US-2016293389-A1
Application number	US-201615088834-A
Country	US
Kind code	A1
Filing date	Apr 1, 2016
Priority date	Apr 3, 2015
Publication date	Oct 6, 2016
Grant date	—

Abstract

A method and apparatus is provided for obtaining a low average electron energy flux onto a substrate in a processing chamber. A processing chamber includes a substrate support therein for chemical processing. An energy source induced plasma, and ion propelling means, directs energetic plasma electrons toward the substrate support. A dipole ring magnet field is applied perpendicular to the direction of ion travel, to effectively prevent electrons above an acceptable maximum energy level from reaching the substrate holder. Rotation of the dipole magnetic field reduces electron non-uniformities.

First claim

What is claimed is:

1 . A method of obtaining a low average electron energy flux onto a substrate in a processing chamber, comprising:
supporting a substrate for processing at a first end of a processing chamber with a surface of the substrate facing a processing space in said processing chamber that contains a processing gas; coupling energy into the processing space to form a plasma containing ions of the processing gas at a second end of the chamber opposite the substrate; allowing electrons to propagate in a direction from said second end of the processing chamber toward the substrate at said first end of the processing chamber; applying a dipole magnetic field, transversely across the chamber and perpendicular to said direction, along a portion of said processing space, the strength, height, and position of said dipole magnetic field being established, in relation to said energy, to cause electrons having energies above an acceptable maximum level to divert from said direction to produce a high concentration of electrons having energies at or below the acceptable maximum near the substrate.

2 . The method of claim 1 , wherein the portion originates at a distance spaced from said second end wherein the plasma that is no longer exothermic.

3 . The method of claim 2 , wherein said region extends sufficiently from where said region originates toward said substrate to allow for electron cooling and low energy selection, yet is sufficiently short to minimize plasma density loss.

4 . The method of claim 1 further comprising rotating the dipole magnetic field.

5 . The method of claim 1 wherein the energy is microwave energy.

6 . The method of claim 5 wherein the coupling of the microwave energy into the processing space is from a Radial Line Slot Antenna at the second end of the processing chamber.

7 . The method of claim 1 , wherein:
the portion originates at a distance spaced from said second end wherein the plasma is no longer exothermic and extends sufficiently from where said region originates toward said substrate to allow for electron cooling and low energy selection, yet is sufficiently short to minimize plasma density loss; the applying of the dipole magnetic field includes rotating the dipole magnetic field about an axis extending through the center of the processing chamber in said direction; and the coupling of energy into the processing space includes coupling microwave energy into the processing space from an Radial Line Slot Antenna at the second end of the processing chamber; and

8 . A plasma processing apparatus for performing the method of claim 7 , comprising:
a processing chamber having a plasma processing space therein; a substrate support in the processing chamber at a first end thereof for supporting a substrate thereon with a processing side thereof facing the processing space; a microwave energized Radial Line Slot Antenna energy source coupled into the processing space so as to form a plasma at a second end of the chamber opposite said first end; a dipole ring magnet (DRM) source operatively disposed coaxial with, and exterior to, said processing chamber, configured to produce a magnetic field across the chamber and perpendicular to the path of electrons moving from the plasma at said second end of the chamber toward said substrate at said first end of the chamber; wherein said DRM source is configured to rotate said dipole magnetic field about an axis extending through the center of the processing chamber in said direction, and wherein said dipole magnetic field originates at a distance spaced from said second end wherein the plasma is no longer exothermic and extends sufficiently from where said region originates toward said substrate to allow for electron cooling and low energy selection, yet is sufficiently short to minimize plasma density loss.

9 . A plasma processing apparatus for performing the method of claim 1 , comprising:
a processing chamber having a plasma processing space therein; a substrate support in the processing chamber at a first end thereof for supporting a substrate thereon with a processing side thereof facing the processing space; an energy source coupled into the processing space so as to form a plasma at a second end of the chamber opposite said first end; a DRM source operatively disposed coaxial with, and exterior to, said processing chamber, configured to produce a magnetic field across the chamber and perpendicular to the path of electrons moving from the plasma at said second end of the chamber toward said substrate at said first end of the chamber.

10 . A plasma processing apparatus, comprising:
a processing chamber having a plasma processing space therein; a substrate support in the processing chamber at a first end thereof for supporting a substrate thereon with a processing side thereof facing the processing space; a plasma source coupled into the processing space so as to form a plasma at a second end of the chamber opposite said first end; a DRM operatively disposed coaxial with, and exterior to, said processing chamber, the DRM having an array of magnets spaced around the chamber and oriented to produce a magnetic field across the chamber and perpendicular to the path of electrons moving from the plasma at said second end of the chamber toward said substrate at said first end of the chamber.

11 . The apparatus of claim 10 , further comprising:
the plasma source including an Radial Line Slot Antenna at said second end of the processing chamber; a quartz window forming a sealed interface between said RSLA and said processing space; and a microwave energy source coupled to said RSLA.

12 . The plasma processing apparatus of claim 10 , wherein said DRM is comprised of a plurality magnetic columns.

13 . The plasma processing apparatus of claim 12 , wherein said magnetic columns include a stacked plurality of discrete permanent magnetic elements that achieve a magnetic column of desired length.

14 . The plasma processing apparatus of claim 10 , wherein said DRM is configured to rotate coaxially about an axis perpendicular to the center of said substrate support.

15 . The plasma processing apparatus of claim 10 , wherein said DRM is configured with adequate magnetic field strength to selectively allow low energy electrons to pass from the second end of said processing chamber to a substrate on the substrate support.

16 . The plasma processing apparatus of claim 10 , wherein said DRM is positioned such that a first circumferential edge of said DRM originates at a distance from said second end where the plasma reaction is no longer exothermic.

17 . The plasma processing apparatus of claim 16 , wherein the length of said DRM is sufficiently long to allow for electron cooling and low energy selection, yet sufficiently short to minimize plasma density loss.

18 . The plasma processing apparatus of claim 17 , wherein a second circumferential edge of said DRM terminates nearly coincident with a plane formed by said substrate support.

19 . The plasma processing apparatus of claim 17 , wherein a second circumferential edge of said DRM terminates at distance from said substrate support in said processing space.

20 . The plasma processing apparatus of claim 17 , wherein the magnets of the array are permanent magnets.

Assignees

• Tokyo Electron Ltd
• Univ Houston System

Inventors

• Chen Lee
• Economou Demetre J
• Zhao Jianping
• Funk Merritt

Classifications

• H01J37/32293

  using particular waveforms, e.g. polarised waves · CPC title

• H01J37/3222

  Antennas · CPC title

• H01J37/32669 Primary

  Particular magnets or magnet arrangements for controlling the discharge · CPC title

• H01J2237/152

  Magnetic means · CPC title

• H01J37/32238

  Windows · CPC title