PLASMA APPARATUS AND METHOD OF OPERATING THE SAME

• US 20160056017A1
• Filed: 07/15/2015
• Published: 02/25/2016
• Est. Priority Date: 08/19/2014
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: LEE, Unjoo, KIM, Moojin, KIM, Bongseong
• Granted Patent: US 9,704,690 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H01J 37/321 the radio frequency energy being inductively coupled to the plasma
• CPC Class Codes: H01J 37/32706 Polarising the substrate
• CPC Class Codes: H01J 37/32972 Spectral analysis

Abstract

A plasma apparatus includes a chuck disposed in a process chamber, a gas supply unit supplying a process gas into the process chamber, a plasma generating unit configured to generate plasma over the chuck, a direct current (DC) power generator applying a DC pulse signal to the chuck, and a sensor monitoring a state of the plasma and providing a sensing signal to the DC power generator. Each period of the DC pulse signal includes a negative pulse duration, a positive pulse duration, and a pulse-off duration. If a signal disturbance of the sensing signal occurs in an n^th period of the DC pulse signal, the DC power generator changes a magnitude of a positive pulse and/or a length of the positive pulse duration of an n+1^th period of the DC pulse signal, where “n” denotes a natural number.

Claims

1. A plasma apparatus comprising:

a process chamber having an inner, enclosed space;

a chuck disposed in the process chamber and having a top surface configured to load a substrate;

a gas supply unit supplying a process gas into the process chamber;

a plasma generating unit configured to generate plasma over the chuck;

a direct current (DC) power generator configured to apply a DC pulse signal to the chuck; and

a sensor configured to monitor a state of the plasma and provide a sensing signal to the DC power generator,

wherein the DC pulse signal comprises a series of periods, wherein each period of the DC pulse signal comprises;

a negative pulse duration during which a negative pulse is applied;

a positive pulse duration during which a positive pulse is applied; and

a pulse-off duration during which the negative pulse and the positive pulse are turned-off, and

wherein the DC power generator is configured to change at least one of a magnitude of the positive pulse and a length of the positive pulse duration of an n+1^th period of the DC pulse signal, where “

n”

denotes a natural number, upon detecting a signal disturbance of the sensing signal in an n^th period of the DC pulse signal.

2. The plasma apparatus of claim 1, wherein the DC power generator comprises:

a negative power supply generating the negative pulse;

a positive power supply generating the positive pulse;

an output terminal electrically connected to the chuck;

a pulse modulator; and

a controller electrically connected to the sensor,

wherein the pulse modulator is configured to connect the output terminal with the negative power supply to supply the negative pulse, and the positive power supply to supply the positive pulse at different times, and

wherein the controller is configured to control the negative power supply, the positive power supply, and the pulse modulator, and

wherein the controller is further configured to change at least one of the magnitude of the positive pulse and the length of the positive pulse duration upon detection of a disturbance from the sensing signal.

3. The plasma apparatus of claim 1, wherein the DC power generator is configured to increase at least one of the magnitude of the positive pulse and the length of the positive pulse duration of the n+1^th period in response to detecting a disturbance from the sensing signal during the negative pulse duration of the n^th period.

4. The plasma apparatus of claim 1, wherein the DC power generator is configured to reduce at least one of the magnitude of the positive pulse and the length of the positive pulse duration of the n+1^th period in response to detecting a disturbance from the sensing signal during the positive pulse duration of the n^th period.

5. The plasma apparatus of claim 1, wherein the positive pulse duration is after the negative pulse duration and before the pulse-off duration in each period of the DC pulse signal,

wherein each period of the DC pulse signal further comprises:

a stable duration after the negative pulse duration and before the positive pulse duration, and

wherein a ground voltage is applied during the stable duration and the pulse-off duration.

6. The plasma apparatus of claim 5, wherein a length of the stable duration of the n^th period is different from a length of the pulse-off duration of the n^th period.

7. The plasma apparatus of claim 1, wherein a total length of the n^th period is equal to a total length of the n+1^th period.

8. The plasma apparatus of claim 1, wherein the DC power generator changes at least one of a magnitude of the positive pulse and a length of the positive pulse duration of an n+2^th period in response to detecting a disturbance form the sensing signal during the n^th period.

9. The plasma apparatus of claim 3, wherein the DC power generator is configured to further increase at least one of a magnitude of the positive pulse and a length of the positive pulse duration of the n+x^th period as compared to at least one of the magnitude of the positive pulse and the length of the positive pulse duration of the n+y^th period, where “

x”

denotes a natural number greater than or equal to 2 and where “

y”

denotes a natural number less than “

x”

by 1.

10. The plasma apparatus of claim 4, wherein the DC power generator is configured to further reduce at least one of a magnitude of the positive pulse and a length of the positive pulse duration of the n+2^th period in response to detecting a disturbance form the sensing signal during the n^th period.

11. The plasma apparatus of claim 1,

wherein a magnitude of the negative pulse of the n^th period is greater than a magnitude of the positive pulse of the n^th period, and

wherein a magnitude of the negative pulse of the n+1^th period is greater than the magnitude of the positive pulse of the n+1^th period.

12. The plasma apparatus of claim 1,

wherein the chuck is an electrostatic chuck, and

wherein an insulator is disposed between the chuck and the bottom plate of the process chamber.

13. The plasma apparatus of claim 1, wherein the DC power generator is configured to apply the DC pulse signal to an outer ring disposed on an edge of the chuck and surrounding the loaded substrate.

14. The plasma apparatus of claim 1,

wherein the sensor is configured to measure an intensity of a light generated from the plasma and provide the sensing signal in real time, and

wherein the sensor is an optical emission sensor.

15. The plasma apparatus of claim 1, wherein the DC pulse signal is offset by a non-zero DC voltage.

16. The plasma apparatus of claim 1, wherein a magnitude of the negative pulse is in a range of 50 V to 10 kV, and a magnitude of the positive pulse PP1 is in a range of 15 V to 3 kV.

17. The plasma apparatus of claim 7, wherein a reciprocal of the period of the DC pulse signal is in a range of 50 Hz to 500 kHz.

18. The plasma apparatus of claim 5, wherein the negative pulse duration is less than the sum of the positive pulse duration, the pulse-off duration, and the stable duration.

19. The plasma apparatus of claim 5, wherein the pulse-off duration is in a range of twice as long and 100 times as long as the stable duration.

20. The plasma apparatus of claim 1, wherein the DC power generator is a first DC power generator and the DC pulse signal is a first DC pulse signal, and the plasma apparatus further comprises:

an outer ring disposed on an edge of the chuck and surrounding the loaded substrate,

a second direct current (DC) power generator configured to apply a second DC pulse signal having continuous periods to the outer ring,

wherein each period of the second DC pulse signal comprises;

a second negative pulse duration during which a second negative pulse is applied;

a second positive pulse duration during which a second positive pulse is applied; and

a pulse-off duration during which the second negative pulse and the second positive pulse are turned-off,

wherein the first and second DC power generators are configured to apply the first and second DC pulse signals at the same time, and

wherein each period of the second DC pulse signal is synchronized with each period of the first DC pulse signal.

21. The plasma apparatus of claim 2, wherein the pulse modulator is further configured to connect the output terminal with a ground source supplying a ground reference voltage to supply the ground reference voltage in between times the pulse modulator connects the output terminal with the negative power supply and the positive power supply.

22. A method of operating a plasma apparatus, the method comprising:

loading a substrate on a chuck disposed in a process chamber;

supplying a process gas into the process chamber;

generating plasma over the chuck;

applying a direct current (DC) pulse signal to the chuck by a DC power generator, each period of the DC pulse signal comprising;

a negative pulse duration during which a negative voltage pulse is applied;

a positive pulse duration during which a positive voltage pulse is applied; and

a pulse-off duration during which a third voltage with a magnitude that is not greater than either magnitude of the negative voltage pules and the positive voltage pulse is applied to the chuck;

monitoring a state of the plasma by a sensor;

providing a sensing signal to the DC power generator by the sensor; and

changing at least one of a magnitude of the positive voltage pulse and a length of the positive pulse duration of an n+1^th period of the DC pulse signal by the DC power generator if a signal disturbance of the sensing signal occurs in an n^th period of the DC pulse signal, where “

n”

denotes a natural number.

23. The method of claim 22, wherein, if the signal disturbance occurs in the negative pulse duration of the n^th period, the at least one of the magnitude of the positive voltage pulse and the length of the positive pulse duration of the n+1^th period is increased compared to at least one of a magnitude of the positive voltage pulse and a length of the positive pulse duration of the n^th period.

24. The method of claim 22, wherein, if the signal disturbance occurs in the positive pulse duration of the n^th period, the at least one of the magnitude of the positive voltage pulse and the length of the positive pulse duration of the n+1^th period is reduced as compared to at least one of a magnitude of the positive voltage pulse and a length of the positive pulse duration of the n^th period.

25. The method of claim 22, wherein the positive pulse duration is after the negative pulse duration and before the pulse-off duration in each period of the DC pulse signal,

wherein each period of the DC pulse signal further comprises:

a stable duration after the negative pulse duration and before the positive pulse duration, and

wherein the third voltage is a ground voltage and is applied during the stable duration and the pulse-off duration.

26. The method of claim 22, wherein the third voltage is in a range of negative 500 V to positive 500 V.

27. The method of claim 22 wherein the DC pulse signal is a first DC pulse signal, and the method further comprises:

applying a second DC pulse signal by a second DC power generator to an outer ring disposed on an edge of the chuck and surrounding the loaded substrate, each period of the second DC pulse signal comprising;

a negative pulse duration during which a negative voltage pulse is applied;

a positive pulse duration during which a positive voltage pulse is applied; and

a pulse-off duration during which the negative pulse and the positive pulse are turned-off,

wherein the second DC pulse signal is synchronized with the first DC pulse signal.

28. The method of claim 22 further comprising:

applying the first DC pulse signal to an outer ring disposed on an edge of the chuck and surrounding the loaded substrate.

29. A method of operating a plasma apparatus, the method comprising:

loading a substrate on a chuck within a vacuum chamber;

generating a radio frequency (RF) plasma power;

transmitting the RF plasma power to the vacuum chamber through a matching unit and an antenna electrode;

supplying gas into the vacuum chamber;

periodically applying a voltage signal to the chuck by a first power generator, each period of the voltage signal comprising;

a negative voltage duration during which a varying negative voltage is applied;

a positive voltage duration during which a positive voltage is applied; and

an interrupted duration during which a ground voltage is applied;

monitoring a state of the plasma by a sensor;

providing a sensing signal to the power generator by the sensor; and

changing both a magnitude of the positive voltage pulse and a length of the positive pulse duration by the power generator of a second period after a disturbance of the sensing signal is detected,

wherein the disturbance comprises a pulse of the sensing signal during either the negative voltage duration or positive voltage duration of the first period of the voltage signal.

30. The method of operating a plasma apparatus of claim 29 further comprising:

changing at least one of a magnitude of the positive voltage pulse and a length of the positive pulse duration by the power generator of a third period following the second period of the voltage signal when a second signal disturbance of the sensing signal is detected,

wherein the second signal disturbance comprises a pulse of the sensing signal having lesser magnitude than in the first signal disturbance during the negative voltage duration or positive voltage duration of the second period of the voltage signal.

31. The method of operating a plasma apparatus of claim 29, wherein the monitoring of a state of the plasma comprises sensing an intensity of light.

32. The method of operating a plasma apparatus of claim 29, wherein the changing of at least one of the magnitude of the positive voltage pulse and the length of the positive pulse duration of an n+1^th period of the first DC pulse signal is an automatic response to an arcing phenomenon detected by the sensor in an n^th period.