Method for controlling a plasma chamber

Patent metadata

Field	Value
Publication number	US-9745660-B2
Application number	US-201514702900-A
Country	US
Kind code	B2
Filing date	May 4, 2015
Priority date	May 2, 2014
Publication date	Aug 29, 2017
Grant date	Aug 29, 2017

Abstract

An system and method for controlling a plasma chamber includes operably coupling an RF generator to the plasma chamber, the RF generator providing an RF signal to a chamber input of the plasma chamber; measuring a parameter at the chamber input; determining a rate of change based on the measured parameter; detecting an excessive rate of change condition comprising the rate of change exceeding a reference rate of change; detecting a repetitive change condition comprising a predetermined number of the excessive rate of change conditions in a predetermined time; upon detection of the repetitive change condition, decreasing a power of the RF signal provided to the chamber input.

First claim

What is claimed is:

1. A system for controlling a plasma chamber, the system comprising:
an RF generator operably coupled to a chamber input of the plasma chamber, the RF generator configured to provide an RF signal to the chamber input;
a sensor component configured to measure a parameter at the chamber input; and
a control unit configured to:
receive a sensor signal from the sensor component, the sensor signal indicative of the measured parameter;
determine a rate of change based on the measured parameter;
detect an excessive rate of change condition comprising the rate of change exceeding a reference rate of change;
detect a repetitive change condition comprising a predetermined number of the excessive rate of change conditions in a predetermined time; and
upon detection of the repetitive change condition, decrease a power of the RF signal provided to the chamber input.

2. The system of claim 1 wherein the measured parameter is one of:
an amplitude of a voltage of the RF signal at the chamber input; and
an amplitude of a current of the RF signal at the chamber input.

3. The system of claim 2 wherein the control unit is further configured to determine a phase angle between the voltage and the current of the RF signal.

4. The system of claim 3 wherein the rate of change is at least one of:
a rate of change of the amplitude of the voltage (the voltage rate of change);
a rate of change of the amplitude of the current (the current rate of change); and
a rate of change of the phase angle (the phase angle rate of change).

5. The system of claim 4 wherein the excessive rate of change condition comprises one of:
the voltage rate of change exceeding a reference voltage rate of change;
the current rate of change exceeding a reference current rate of change; and
the phase angle rate of change exceeding a reference phase angle rate of change.

6. A method for controlling a plasma chamber, the method comprising:
operably coupling an RF generator to the plasma chamber, the RF generator providing an RF signal to a chamber input of the plasma chamber;
measuring a parameter at the chamber input;
determining a rate of change based on the measured parameter;
detecting an excessive rate of change condition comprising the rate of change exceeding a reference rate of change;
detecting a repetitive change condition comprising a predetermined number of the excessive rate of change conditions in a predetermined time; and
upon detection of the repetitive change condition, decreasing a power of the RF signal provided to the chamber input.

7. The method of claim 6 wherein the measured parameter is one of:
an amplitude of a voltage of the RF signal at the chamber input; and
an amplitude of a current of the RF signal at the chamber input.

8. The method of claim 7 further comprising determining a phase angle between the voltage and the current of the RF signal.

9. The method of claim 8 wherein the rate of change is at least one of:
a rate of change of the amplitude of the voltage (the voltage rate of change);
a rate of change of the amplitude of the current (the current rate of change); and
a rate of change of the phase angle (the phase angle rate of change).

10. The method of claim 9 wherein the excessive rate of change condition comprises one of:
the voltage rate of change exceeding a reference voltage rate of change;
the current rate of change exceeding a reference current rate of change; and
the phase angle rate of change exceeding a reference phase angle rate of change.

11. The method of claim 10 further comprising:
receiving a first signal from a sensor component, the first signal indicative of the amplitude of the voltage of the RF signal at the chamber input; and
receiving a second signal from the sensor component, the second signal indicative of the amplitude of the current of the RF signal at the chamber input.

12. The method of claim 11 further comprising:
receiving at a voltage detector the first signal from the sensor component, the voltage detector configured to output a voltage DC signal;
receiving at a current detector the second signal from the sensor component, the current detector configured to output a current DC signal;
receiving at a phase detector the first signal and the second signal from the sensor component, the phase detector configured to output a phase angle DC signal;
receiving the current DC signal, the voltage DC signal, the phase angle DC signal, and a reference signal;
detecting the excessive rate of change condition based on the current DC signal, the voltage DC signal, the phase angle DC signal, and the reference signal;
sending a power control signal to the RF generator or a matching network to cause the decrease of the power of the RF signal provided to the chamber input.

13. The method of claim 12 wherein the power control signal is sent to the matching network, the matching network altering the capacitance value of a variable capacitor to decrease the power of the RF signal provided to the chamber input.

14. The method of claim 6 further comprising increasing the power of the RF signal provided to the chamber input when the repetitive change condition is no longer detected.

15. The method of claim 6 wherein an impedance matching network is coupled between the RF generator and the plasma chamber.

16. A method of manufacturing a semiconductor, the method comprising:
placing a substrate in a plasma chamber configured to deposit a material layer onto the substrate or etch a material layer from the substrate; and
energizing plasma within the plasma chamber by operably coupling an RF generator to the plasma chamber, the RF generator providing an RF signal to a chamber input of the plasma chamber, the RF signal having a current, a voltage, and a phase angle between the voltage and the current, and while energizing the plasma:
measuring a parameter at the chamber input;
determining a rate of change based on the measured parameter;
detecting an excessive rate of change condition comprising the rate of change exceeding a reference rate of change;
detecting a repetitive change condition comprising a predetermined number of the excessive rate of change conditions in a predetermined time; and
upon detection of the repetitive change condition, decreasing a power of the RF signal provided to the chamber input.

17. The method of claim 16 wherein the measured parameter is one of:
an amplitude of a voltage of the RF signal at the chamber input; and
an amplitude of a current of the RF signal at the chamber input.

18. The method of claim 17 further comprising determining a phase angle between the voltage and the current of the RF signal.

19. The method of claim 18 wherein the rate of change is at least one of:
a rate of change of the amplitude of the voltage (the voltage rate of change);
a rate of change of the amplitude of the current (the current rate of change); and
a rate of change of the phase angle (the phase angle rate of change).

20. The method of claim 19 wherein the excessive rate of change condition comprises one of:
the voltage rate of change exceeding a reference voltage rate of change;
the current rate of change exceeding a reference current rate of change; and
the phase angle rate of change exceeding a reference phase angle rate of change.

Assignees

• Reno Tech Inc

Inventors

• Bhutta Imran Ahmed

Classifications

• H10P74/238

  comprising acting in response to an ongoing measurement without interruption of processing, e.g. endpoint detection or in-situ thickness measurement · CPC title

• H01J37/3299

  Feedback systems · CPC title

• H01J37/32935

  Monitoring and controlling tubes by information coming from the object and/or discharge · CPC title

• H01J37/32082

  Radio frequency generated discharge (H01J37/32357, H01J37/32366, H01J37/32394 and H01J37/32403 take precedence) · CPC title

• C23C16/52

  Controlling or regulating the coating process {(C23C16/45557, C23C16/279 take precedence)} · CPC title