Plasma processing apparatus and method for generating plasma

Patent metadata

Field	Value
Publication number	US-10978274-B2
Application number	US-201916645188-A
Country	US
Kind code	B2
Filing date	Jun 10, 2019
Priority date	Jun 22, 2018
Publication date	Apr 13, 2021
Grant date	Apr 13, 2021

Abstract

The plasma processing apparatus according to an exemplary embodiment includes a chamber, a radio-frequency power supply, and a correction signal generator. The radio-frequency power supply outputs a pulsed radio-frequency power in a first period. The radio-frequency power supply outputs a pulsed radio-frequency power in one or more second periods after the first period. The correction signal generator generates a correction signal that oscillates in a reverse phase with respect to a reflected wave monitor signal in the first period. The radio-frequency power supply generates a combined radio-frequency power using the correction signal. The power supply is configured to alternately repeat output of the pulsed radio-frequency power in the first period and output of the combined radio-frequency power in the one or more second periods.

First claim

What is claimed is:

1. An apparatus for plasma processing comprising:
a chamber;
a radio-frequency power supply configured to output a pulsed radio-frequency power or a combined radio-frequency power in order to generate plasma from a gas in the chamber, wherein the combined radio-frequency power is a combined power of the pulsed radio-frequency power with a correction radio-frequency power that oscillates in a reverse phase with respect to a reflected wave of the pulsed radio-frequency power; and
a correction signal generator configured to generate a correction signal that oscillates in a reverse phase with respect to a reflected wave monitor signal representing the reflected wave of the pulsed radio-frequency power,
wherein the radio-frequency power supply is configured to output the pulsed radio-frequency power in a first period,
the correction signal generator is configured to generate the correction signal from the reflected wave monitor signal in the first period, and
the radio-frequency power supply is configured to output the combined radio-frequency power generated using the correction signal in each of one or more second periods after the first period, and alternately repeat output of the pulsed radio-frequency power in the first period and output of the combined radio-frequency power in the one or more second periods.

2. The apparatus according to claim 1 , wherein the first period and the one or more second periods are respectively same as a plurality of successive cycles specified by a predetermined frequency.

3. The apparatus according to claim 1 , wherein the plasma processing apparatus includes the radio-frequency power supply as a first radio-frequency power supply, and further comprises:
a support stage having a lower electrode and configured to support a substrate thereon in the chamber;
a second radio-frequency power supply electrically connected to the support stage and configured to output another radio-frequency power, wherein a frequency of the another radio-frequency power is lower than a frequency of the pulsed radio-frequency power; and
a synchronization signal generator configured to generate a synchronization signal synchronized with the other radio-frequency power,
wherein the first period and the one or more second periods are respectively same as a plurality of successive cycles of the other radio-frequency power, and
wherein the first radio-frequency power supply is configured to generate the pulsed radio-frequency power in the first period according to the synchronization signal, and generate the combined radio-frequency power in each of the one or more second periods in response to the synchronization signal.

4. The apparatus according to claim 1 , further comprising:
a directional coupler provided on an electric path through which the pulsed radio-frequency power output from the radio-frequency power supply and the combined radio-frequency power are transmitted,
wherein the correction signal generator is configured to generate the correction signal from the reflected wave monitor signal output by the directional coupler,
wherein the radio-frequency power supply includes:
a radio-frequency signal generator configured to generate a pulsed radio-frequency signal,
an adder configured to add the correction signal to the pulsed radio-frequency signal, thereby generating a combined radio-frequency signal, and
an amplifier configured to amplify the pulsed radio-frequency signal to generate the pulsed radio-frequency power, and amplify the combined radio-frequency signal to generate the combined radio-frequency power, and

wherein the correction signal is not added to the pulsed radio-frequency signal in the first period.

5. The apparatus according to claim 4 , wherein the first period and the one or more second periods are respectively same as a plurality of successive cycles specified by a predetermined frequency.

6. The apparatus according to claim 4 , wherein the plasma processing apparatus includes the radio-frequency power supply as a first radio-frequency power supply, and further comprises:
a support stage having a lower electrode and configured to support a substrate thereon in the chamber;
a second radio-frequency power supply electrically connected to the support stage and configured to output another radio-frequency power, wherein a frequency of the another radio-frequency power is lower than a frequency of the pulsed radio-frequency power; and
a synchronization signal generator configured to generate a synchronization signal synchronized with the other radio-frequency power,
wherein the first period and the one or more second periods are respectively same as a plurality of successive cycles of the other radio-frequency power, and
wherein the first radio-frequency power supply is configured to generate the pulsed radio-frequency power in the first period according to the synchronization signal, and generate the combined radio-frequency power in each of the one or more second periods in response to the synchronization signal.

7. The apparatus according to claim 4 , wherein the correction signal generator is configured to generate the correction signal by generating a reverse phase signal of the reflected wave monitor signal, and correcting the reverse phase signal so as to eliminate a dependency of an amplification factor on an amplitude of an input signal of the amplifier.

8. The apparatus according to claim 7 , wherein the first period and the one or more second periods are respectively same as a plurality of successive cycles specified by a predetermined frequency.

9. The apparatus according to claim 7 , wherein the apparatus includes the radio-frequency power supply as a first radio-frequency power supply, and further comprises:
a support having a lower electrode and configured to support a substrate thereon in the chamber;
a second radio-frequency power supply electrically connected to the support and configured to output another radio-frequency power, wherein a frequency of the another radio-frequency power is lower than a frequency of the pulsed radio-frequency power; and
a synchronization signal generator configured to generate a synchronization signal synchronized with the other radio-frequency power,
wherein the first period and the one or more second periods are respectively same as a plurality of successive cycles of the other radio-frequency power, and
wherein the first radio-frequency power supply is configured to generate the pulsed radio-frequency power in the first period according to the synchronization signal, and generate the combined radio-frequency power in each of the one or more second periods in response to the synchronization signal.

10. A method of generating plasma within a chamber of an apparatus for plasma processing, the method comprising:
outputting a pulsed radio-frequency power in a first period to generate plasma from a gas in the chamber;
generating a correction signal that oscillates in a reverse phase with respect to a reflected wave monitor signal representing a reflected wave of the pulsed radio-frequency power; and
outputting a combined radio-frequency power in each of one or more second periods after the first period to generate plasma from gas in the chamber, wherein the combined radio-frequency power is a combined power of the pulsed radio-frequency power with a correction radio-frequency power that oscillates in a reverse phase with respect to the reflected wave of the pulsed radio-frequency power, the correction radio-frequency power being generated using the correction signal,
wherein the outputting the pulsed radio-frequency power and the outputting the combined radio-frequency power are executed su

Assignees

• Tokyo Electron Ltd

Inventors

• Kubota Shinji

Classifications

• H10P50/242

  of Group IV materials · CPC title

• H01J37/32642

  Focus rings · CPC title

• C23C16/505

  using radio frequency discharges · CPC title

• H01J37/32183 Primary

  Matching circuits · CPC title

• H05H1/46

  using applied electromagnetic fields, e.g. high frequency or microwave energy (H05H1/26 takes precedence) · CPC title