Methods and apparatus for synchronizing RF pulses in a plasma processing system

Patent metadata

Field	Value
Publication number	US-9368329-B2
Application number	US-201213550719-A
Country	US
Kind code	B2
Filing date	Jul 17, 2012
Priority date	Feb 22, 2012
Publication date	Jun 14, 2016
Grant date	Jun 14, 2016

Abstract

A synchronized pulsing arrangement for providing at least two synchronized pulsing RF signals to a plasma processing chamber of a plasma processing system is provided. The arrangement includes a first RF generator for providing a first RF signal. The first RF signal is provided to the plasma processing chamber to energize a plasma therein, the first RF signal representing a pulsing RF signal. The arrangement also includes a second RF generator for providing a second RF signal to the plasma processing chamber. The second RF generator has a sensor subsystem for detecting values of at least one parameter associated with the plasma processing chamber that reflects whether the first RF signal is pulsed high or pulsed low and a pulse controlling subsystem for pulsing the second RF signal responsive to the detecting the values of at least one parameter.

First claim

What is claimed is:

1. A synchronized pulsing arrangement comprising:
a first RF generator for providing a first RF signal, said first RF signal provided to a plasma processing chamber to energize plasma therein, said first RF signal representing a pulsing RF signal; and
a second RF generator for providing a second RF signal to said plasma processing chamber, said second RF generator having a sensor subsystem for detecting at an output of the second RF generator values of at least one parameter associated with said plasma processing chamber indicating a change in pulsing of said first RF signal from a first state to a second state, said second RF generator having a pulse controlling subsystem for pulsing said second RF signal provided by the second RF generator in response to detecting that the values of said at least one parameter at the output of the second RF generator indicate a change in pulsing of said first RF signal from the first state to the second state,
wherein the first RF signal in the first state has a different forward power level from a forward power level of the first RF signal in the second state,
wherein the first RF generator and the sensor subsystem of the second RF generator are coupled to an impedance matching network.

2. The synchronized pulsing arrangement of claim 1 , wherein said sensor subsystem of the second RF generator is configured to detect the at least one parameter that represents at least one of forward RF power and reflected RF power.

3. The synchronized pulsing arrangement of claim 1 , wherein said sensor subsystem of the second RF generator is configured to detect the at least one parameter that represents gamma that further represents a numerical index indicating a degree of mismatch between reflected power and forward power of said second RF generator.

4. The synchronized pulsing arrangement of claim 1 , further comprising a tool host computer, said tool host computer providing at least a trigger threshold value to enable circuitry in said sensor subsystem of said second RF generator to ascertain whether said first RF signal is pulsed from the first state to the second state.

5. The synchronized pulsing arrangement of claim 4 , wherein said pulse controlling subsystem is configured to generate at least a high level and a low level for said second RF signal, said high level and said low level governed by at least one value provided said tool host computer.

6. The synchronized pulsing arrangement of claim 1 , wherein said second RF generator is configured to generate the second RF signal that has at least a high pulse value and a non-zero low pulse value.

7. The synchronized pulsing arrangement of claim 1 , wherein said sensor subsystem of the second RF generator is configured to detect the at least one parameter that represents the values obtained from a VI probe.

8. The synchronized pulsing arrangement of claim 1 , wherein said sensor subsystem of the second RF generator is configured to detect the at least one parameter that represents an output impedance of said second RF generator.

9. The synchronized pulsing arrangement of claim 1 , wherein the impedance matching network is coupled to outputs of said first RF generator and said second RF generator, wherein said sensor subsystem of the second RF generator is configured to detect the at least one parameter that represents an impedance of an input of said impedance matching network.

10. The synchronized pulsing arrangement of claim 1 , wherein said second RF generator is configured to generate the second RF signal that includes at least a predefined high pulse value and a predefined low pulse value.

11. The synchronized pulsing arrangement of claim 10 , further comprising control circuitry for generating a pulse control signal to control pulsing by said first RF generator and wherein said second RF generator does not pulse responsive to a signal from said control circuitry, said second RF generator pulses at least one of high-to-low and low-to-high responsive to said detecting said values of said at least one parameter associated with said plasma processing chamber that reflects whether said first RF signal is pulsed high or pulsed low.

12. The synchronized pulsing arrangement of claim 1 , wherein said second RF generator is configured to generate the second RF signal that has at least a predefined high pulse value and a predefined low pulse value and wherein second RF generator is configured to generate the second RF signal that transitions, after a predefined duration expires after being pulsed from said predefined low pulse value to said predefined high pulse value, to said predefined pulse low value.

13. The synchronized pulsing arrangement of claim 1 , wherein said second RF generator is configured to generate the second RF signal that includes at least a predefined high pulse value and a predefined low pulse value and wherein said second RF generator is configured to generate the second RF signal that transitions, after a predefined duration expires after being pulsed from said predefined high pulse value to said predefined low pulse value, to said predefined high pulse value.

14. A synchronized pulsing arrangement comprising:
a first RF generator for providing a first RF signal, said first RF signal provided to a plasma processing chamber to energize plasma therein, said first RF signal representing a pulsing RF signal;
control circuitry for generating a pulse control signal to control pulsing by said first RF generator;
a second RF generator for providing a second RF signal to said plasma processing chamber, said second RF generator having a sensor subsystem for detecting at an output of the second RF generator values of at least one parameter associated with said plasma processing chamber indicating a change in pulsing of said first RF signal from a first state to a second state, said second RF generator having a pulse controlling subsystem for pulsing said second RF signal provided by the second RF generator in response to detecting that the values of said at least one parameter at the output of the second RF generator indicate a change in pulsing of said first RF signal from the first state to the second state, wherein the first RF signal in the first state has a different forward power range level from a forward power level of the first RF signal in the second state,
wherein the first RF generator and the sensor subsystem of the second RF generator are coupled to an impedance matching network; and
a third RF generator for providing a third RF signal to said plasma processing chamber, said third RF generator having a sensor subsystem for detecting values at an output of the third RF generator of said at least one parameter associated with said plasma processing chamber indicating a change in pulsing of said first RF signal from the first state to the second state, said third RF generator having a pulse controlling subsystem for pulsing said third RF signal provided by the third RF generator in response to detecting that the values of said at least one parameter at the output of the third RF generator indicate a change in pulsing of said first RF signal from the first state to the second state,
wherein said second RF generator does not pulse responsive to a signal from said control circuitry, said second RF generator pulses said second RF signal at least one of high-to-low and low-to-high responsive to said detecting said values of said at least one parameter associated with said plasma processing chamber, and
wherein said third RF generator does not pulse responsive to the signal from said control circuitry, said third RF generator pulses said

Assignees

• Valcore Jr John C
• Lyndaker Bradford J
• Singh Harmeet
• Lam Res Corp

Inventors

• Valcore Jr John C
• Lyndaker Bradford J
• Singh Harmeet

Classifications

• H01J37/32183 Primary

  Matching circuits · CPC title

• H01J37/32174

  Circuits specially adapted for controlling the RF discharge · CPC title

• H01J37/32146

  Amplitude modulation, includes pulsing · CPC title