Enhanced ignition in inductively coupled plasmas for workpiece processing

Patent metadata

Field	Value
Publication number	US-11348784-B2
Application number	US-201916547724-A
Country	US
Kind code	B2
Filing date	Aug 22, 2019
Priority date	Aug 12, 2019
Publication date	May 31, 2022
Grant date	May 31, 2022

Abstract

Plasma processing apparatus and associated methods are provided. In one example, a plasma processing apparatus includes a plasma chamber. The plasma processing apparatus includes a dielectric wall forming at least a portion of the plasma chamber. The plasma processing apparatus includes an inductive coupling element located proximate the dielectric wall. The plasma processing apparatus includes an ultraviolet light source configured to emit an ultraviolet light beam onto a metal surface that faces an interior volume of the plasma chamber. The plasma processing apparatus includes a controller configured to control the ultraviolet light source.

First claim

What is claimed is:

1. A plasma processing apparatus, comprising:
a plasma chamber;
a dielectric wall forming at least a portion of the plasma chamber;
an inductive coupling element located proximate the dielectric wall,
an ultraviolet light source configured to emit an ultraviolet light beam onto a metal surface of the plasma chamber that faces an interior volume of the plasma chamber; and
a controller configured to control the ultraviolet light source to emit the ultraviolet light beam on the metal surface prior to or at the same time as energizing the inductive coupling element with the radio frequency energy such that a threshold for plasma ignition can be lowered to about the same power density level as is used for sustaining the plasma.

2. The plasma processing apparatus of claim 1 , further comprising one or more reflective elements configured to reflect the ultraviolet light beam onto the metal surface.

3. The plasma processing apparatus of claim 1 , wherein the metal surface is electrically grounded.

4. The plasma processing apparatus of claim 1 , wherein the ultraviolet light source emits the ultraviolet light beam having energy in a wavelength range of about 100 nanometers to about 250 nanometers.

5. The plasma processing apparatus of claim 1 , further comprising an electrostatic shield located between the dielectric wall and the inductive coupling element.

6. The plasma processing apparatus of claim 1 , wherein the ultraviolet light beam passes through a window to reach the metal surface, wherein the window is at least partially transparent to the ultraviolet light beam.

7. The plasma processing apparatus of claim 6 , wherein the window comprises at least one of: synthetic quartz, UV-grade sapphire, magnesium fluoride (MgF 2 ) material, or calcium fluoride (CaF 2 ) material.

8. The plasma processing apparatus of claim 6 , wherein a space between the ultraviolet light source and the window is filled with an inert gas to reduce absorption by atmospheric oxygen, the inert gas comprising at least one of: helium, argon or nitrogen.

9. The plasma processing apparatus of claim 1 , wherein the ultraviolet light source emits the ultraviolet light beam onto the metal surface from a location outside the plasma chamber.

10. The plasma processing apparatus of claim 1 , wherein the ultraviolet light source is a pulsed lamp.

11. The plasma processing apparatus of claim 10 , wherein the pulsed lamp produces a plurality of pulses with a frequency of at least about 100 per second such that the plurality of pulses contributes ultraviolet photons to be incident on the metal surface.

12. The plasma processing apparatus of claim 1 , wherein the ultraviolet light source comprises at least one of: a xenon arc flashlamp, deuterium lamp, or an excimer RF/pulse xenon lamp.

13. The plasma processing apparatus of claim 1 , wherein the plasma chamber is separated from a processing chamber having a workpiece support configured to support a workpiece.

14. A plasma processing apparatus, comprising:
a plasma chamber;
a processing chamber having a workpiece support configured to support a workpiece;
a separation grid separating the processing chamber from the plasma chamber;
a dielectric wall forming at least a portion of the plasma chamber;
an inductive coupling element located proximate the dielectric wall, the inductive coupling element configured to initiate ignition of a plasma in a process gas;
an electrostatic shield located between the dielectric wall and the inductive coupling element;
an ultraviolet light source configured to emit an ultraviolet light beam onto a metal wall at a location facing an interior of the processing chamber; and
a controller configured to control the ultraviolet light source to emit the ultraviolet light beam to impinge on the metal wall of the processing chamber prior to or at the same time as energizing the inductive coupling element with radio frequency (RF) energy such that a threshold for plasma ignition can be lowered to about the same power density level as is used for sustaining the plasma.

15. The plasma processing apparatus of claim 14 , wherein the ultraviolet light beam passes through a window to reach the metal wall, wherein the window is at least partially transparent to the ultraviolet light beam.

16. The plasma processing apparatus of claim 15 , wherein the window comprises at least one of: synthetic quartz, UV-grade sapphire, magnesium fluoride (MgF 2 ) material, or calcium fluoride (CaF 2 ) material.

17. The plasma processing apparatus of claim 16 , wherein a space between the ultraviolet light source and the window is filled with an inert gas to reduce absorption by atmospheric oxygen, the inert gas comprising at least one of: helium, argon, or nitrogen.

18. The plasma processing apparatus of claim 15 , wherein the window is located on between the ultraviolet light source and the metal wall.

Assignees

• Mattson Tech Inc
• Beijing E Town Semiconductor Tech Co Ltd

Inventors

• Savas Stephen E
• Ma Shawming

Classifications

• H10P34/40

  with high-energy radiation · CPC title

• H10P72/0468

  comprising a chamber adapted to a particular process · CPC title

• H10P14/6538

  by exposure to UV light · CPC title

• H10W10/011

  of isolation regions comprising dielectric materials · CPC title

• H10W10/10

  Isolation regions comprising dielectric materials · CPC title