Plasma processing using pulsed-voltage and radio-frequency power
Embodiments of the disclosure provided herein include an apparatus and method for the plasma processing of a substrate in a processing chamber. More specifically, embodiments of this disclosure describe a biasing scheme that is configured to provide a radio frequency (RF) generated RF waveform from an RF generator to one or more electrodes within a processing chamber and a pulsed-voltage (PV) waveform delivered from one or more pulsed-voltage (PV) generators to the one or more electrodes within the processing chamber. The plasma process(es) disclosed herein can be used to control the shape of an ion energy distribution function (IEDF) and the interaction of the plasma with a surface of a substrate during plasma processing.
1. A method of processing of a substrate in a plasma processing chamber, comprising:
delivering, by use of a radio frequency generator, a radio frequency signal to a support base disposed within a substrate support assembly, wherein the radio frequency generator is electrically coupled to the support base through a pulsed voltage filter assembly; and
establishing, by use of a first pulsed-voltage waveform generator, a first pulsed voltage waveform at a biasing electrode disposed within the substrate support assembly, wherein the first pulsed-voltage waveform generator is electrically coupled to the biasing electrode through a first radio frequency filter assembly,
wherein
the biasing electrode is disposed between the support base and a substrate supporting surface of the substrate support assembly,
a first dielectric layer is disposed between the support base and the biasing electrode, and
a second dielectric layer is disposed between the biasing electrode and the substrate supporting surface; and
wherein the first pulsed voltage waveform at the biasing electrode further comprises:
(a) establishing, for a first period of time, a first burst of pulsed voltage waveforms at the biasing electrode, wherein the first burst of pulsed voltage waveforms comprises the first pulsed voltage waveform;
(b) halting, for a second period of time, the establishing of the first burst of pulsed voltage waveforms;
repeating (a) and (b) at least one or more times;
(c) establishing, for a third period of time, a second burst of pulsed voltage waveforms at the biasing electrode, wherein the second burst of the pulsed voltage waveforms comprises a second pulsed voltage waveform that is different from the first pulsed voltage waveform;
(d) halting, for a fourth period of time, the establishing of the second burst of pulsed voltage waveforms; and
repeating (c) and (d) at least one or more times.
2. The method of claim 1 , wherein the first pulsed voltage waveform comprises a series of repeating cycles, such that
a waveform within each cycle has a first portion that occurs during a first time interval and a second portion that occurs during a second time interval,
a positive voltage-pulse is only present during at least a portion of the first time interval,
an output of the first pulsed-voltage waveform generator is connected to a positive voltage supply for at least a portion of a first time interval, and
the pulsed voltage waveform is constant during at least a portion of the second time interval.
3. The method of claim 1 , wherein the second dielectric layer comprises a material that has a finite resistivity.
4. The method of claim 1 , wherein the second dielectric layer has a thickness of between about 0.1 mm and about 2 mm.
5. The method of claim 1 , further comprising sequentially repeating (a), (b), (c) and (d) at least one or more times.
6. The method of claim 5 , wherein the first pulsed voltage waveform comprises a series of repeating cycles, such that
a waveform within each cycle has a first portion that occurs during a first time interval and a second portion that occurs during a second time interval,
a positive voltage-pulse is only present during at least a portion of the first time interval,
an output of the first pulsed-voltage waveform generator is connected to a negative voltage supply for at least a portion of the second time interval, and
the pulsed voltage waveform is constant during at least a portion of the second time interval.
7. The method of claim 1 , wherein the first pulsed voltage waveform comprises a series of repeating cycles, such that
a waveform within each cycle has a first portion that occurs during a first time interval and a second portion that occurs during a second time interval,
a positive voltage-pulse is only present during at least a portion of the first time interval,
an output of the first pulsed-voltage waveform generator is connected to a positive voltage supply for at least a portion of a first time interval, and
the pulsed voltage waveform is constant during at least a portion of the second time interval.
8. The method of claim 1 , wherein the first pulsed voltage waveform comprises a series of repeating cycles, such that
a waveform within each cycle has a first portion that occurs during a first time interval and a second portion that occurs during a second time interval,
a positive voltage-pulse is only present during at least a portion of the first time interval,
an output of a voltage waveform generator is connected to a negative voltage supply for at least a portion of a first time interval, and
the second time interval is longer than the first time interval.
9. The method of claim 1 , wherein the first pulsed voltage waveform comprises a series of repeating cycles, such that
a waveform within each cycle has a first portion that occurs during a first time interval and a second portion that occurs during a second time interval,
a positive voltage-pulse is only present during at least a portion of the first time interval,
an output of the first pulsed-voltage waveform generator is connected to a negative voltage supply for at least a portion of the second time interval, and
the pulsed voltage waveform is constant during at least a portion of the second time interval.
10. The method of claim 9 , wherein the second time interval accounts for at least 50% of each cycle of the series of repeating cycles.
11. The method of claim 1 , wherein the first pulsed voltage waveform comprises a series of repeating cycles, such that
a waveform within each cycle has a first portion that occurs during a first time interval and a second portion that occurs during a second time interval,
a positive voltage-pulse is only present during at least a portion of the first time interval,
an output of a voltage waveform generator is connected to a positive voltage supply for at least a portion of a first time interval, and
the second time interval is longer than the first time interval.
12. The method of claim 11 , wherein the first time interval accounts for less than about 15% of each cycle of the series of repeating cycles.
13. The method of claim 1 , further comprising:
chucking the substrate to the substrate support assembly by establishing a voltage drop between the substrate and the biasing electrode using a chucking module coupled to a biasing electrode through the first radio frequency filter assembly, and
a first generator output coupling assembly that couples an output of the first pulsed-voltage waveform generator to the chucking module, wherein the first generator output coupling assembly is coupled to a blocking capacitor that is disposed between the first generator output coupling assembly and the biasing electrode.
14. The method of claim 13 , further comprising:
a bias compensation module compartment output coupling assembly that is coupled to a transmission line that electrically connects the blocking capacitor to the first radio frequency filter assembly; and
bias compensation circuit elements, wherein the bias compensation circuit elements are electrically coupled between the bias compensation module compartment output coupling assembly and a DC power supply.
15. A method of processing of a substrate in a plasma processing chamber, comprising:
delivering, by use of a radio frequency generator, a radio frequency signal to a support base disposed within a substrate support assembly, wherein the radio frequency generator is electrically coupled to the support base through a pulsed voltage filter assembly;
establishing, by use of a first pulsed-voltage waveform generator, a first pulsed voltage waveform at a biasing electrode disposed within the substrate support assembly, wherein the first pulsed-voltage waveform generator is electrically coupled to the biasing electrode through a first radio frequency filter assembly;
wherein the first pulsed voltage waveform at the biasing electrode further comprises:
(a) establishing, for a first period of time, a first burst of pulsed voltage waveforms at the biasing electrode, wherein the pulsed voltage waveforms of the first burst comprise the first pulsed voltage waveform,
(b) halting, for a second period of time, the establishing of the first burst of pulsed voltage waveforms; and
repeating (a) and (b) at least one or more times; and
establishing, by use of a second pulsed voltage waveform generator, a second pulsed voltage waveform at an edge control electrode disposed within the substrate support assembly, wherein the second pulsed-voltage waveform generator is electrically coupled to the edge control electrode through a second radio frequency filter assembly,
wherein
the biasing electrode is disposed between the support base and a substrate supporting surface of the substrate support assembly,
a first dielectric layer is disposed between the support base and the biasing electrode,
a second dielectric layer is disposed between the biasing electrode and the substrate supporting surface, and
the edge control electrode surrounds at least a portion of the biasing electrode;
wherein the second pulsed voltage waveform at the biasing electrode further comprises:
(c) establishing, for a third period of time, a second burst of pulsed voltage waveforms at the biasing electrode, wherein the second burst of pulsed voltage waveforms comprises a second pulsed voltage waveform that is different from the first pulsed voltage waveform, and
(d) halting, for a fourth period of time, the establishing of the second burst of pulsed voltage waveforms; and
repeating (c) and (d) at least one or more times.
16. The method of claim 15 , wherein the first pulsed voltage waveform comprises a series of repeating cycles, such that
a waveform within each cycle has a first portion that occurs during a first time interval and a second portion that occurs during a second time interval,
a positive voltage-pulse is only present during at least a portion of the first time interval,
an output of the first pulsed-voltage waveform generator is connected to a negative voltage supply for at least a portion of the second time interval, and
the pulsed voltage waveform is constant during at least a portion of the second time interval.
17. The method of claim 16 , wherein the second pulsed voltage waveform comprises a series of repeating cycles, such that
a waveform within each cycle has a first portion that occurs during a first time interval and a second portion that occurs during a second time interval,
a positive voltage-pulse is only present during at least a portion of the first time interval,
an output of the first pulsed-voltage waveform generator is connected to a negative voltage supply for at least a portion of the second time interval, and
the pulsed voltage waveform is constant during at least a portion of the second time interval.
18. The method of claim 15 , further comprising sequentially repeating (a), (b), (c) and (d) at least one or more times.
19. The method of claim 15 , further comprising:
establishing, during the first period of time, a third burst of pulsed voltage waveforms at the edge control electrode, wherein the third burst of pulsed voltage waveforms comprise the first pulsed voltage waveform, the second pulsed voltage waveform or a third pulsed voltage waveform; and
establishing, during the third period of time, a fourth burst of pulsed voltage waveforms at the edge control electrode, wherein the fourth burst of pulsed voltage waveforms comprise the first pulsed voltage waveform, the second pulsed voltage waveform, the third pulsed voltage waveform or a fourth pulsed voltage waveform.
20. The method of claim 15 , further comprising:
establishing, during the first period of time, a second burst of pulsed voltage waveforms at the edge control electrode, wherein the second burst of pulsed voltage waveforms comprise the first pulsed voltage waveform or a second pulsed voltage waveform.
21. The method of claim 20 , wherein the first pulsed voltage waveform and the second pulsed voltage waveform each comprise a series of repeating cycles, such that
a waveform within each cycle has a first portion that occurs during a first time interval and a second portion that occurs during a second time interval,
a positive voltage-pulse is only present during at least a portion of the first time interval,
an output of the first pulsed-voltage waveform generator is connected to a negative voltage supply for at least a portion of the second time interval, and
the pulsed voltage waveform is constant during at least a portion of the second time interval.
22. The method of claim 20 , wherein the first pulsed voltage waveform and the second pulsed voltage waveform each comprise a series of repeating cycles, such that
a waveform within each cycle has a first portion that occurs during a first time interval and a second portion that occurs during a second time interval,
a positive voltage-pulse is only present during at least a portion the first time interval,
an output of a voltage waveform generator is connected to a positive voltage supply for at least a portion of a first time interval, and
the second time interval is longer than the first time interval.
23. The method of claim 20 , wherein the first pulsed voltage waveform and the second pulsed voltage waveform each comprise a series of repeating cycles, such that
a waveform within each cycle has a first portion that occurs during a first time interval and a second portion that occurs during a second time interval,
a positive voltage-pulse is only present during at least a portion the first time interval,
an output of a voltage waveform generator is connected to a negative voltage supply for at least a portion of a first time interval, and
the second time interval is longer than the first time interval.
24. A method of processing of a substrate in a plasma processing chamber, comprising:
delivering, by use of a radio frequency generator, a radio frequency signal to a support base disposed within a substrate support assembly, wherein the radio frequency generator is electrically coupled to the support base through a pulsed voltage filter assembly; and
establishing, by use of a first pulsed-voltage waveform generator, a first pulsed voltage waveform at a biasing electrode disposed within the substrate support assembly, wherein the first pulsed-voltage waveform generator is electrically coupled to the biasing electrode through a first radio frequency filter assembly,
wherein
the biasing electrode is disposed between the support base and a substrate supporting surface of the substrate support assembly, a first dielectric layer is disposed between the support base and the biasing electrode, and
a second dielectric layer is disposed between the biasing electrode and the substrate supporting surface;
wherein the first pulsed voltage waveform comprises a series of repeating cycles, such that
a waveform within each cycle has a first portion that occurs during a first time interval and a second portion that occurs during a second time interval,
a positive voltage-pulse is only present during at least a portion of the first time interval,
an output of the first pulsed-voltage waveform generator is connected to a negative voltage supply for at least a portion of the second time interval, and
the second time interval is longer than the first time interval.
25. The method of claim 24 , further comprising:
(a) establishing, for a first period of time, a first burst of pulsed voltage waveforms at the biasing electrode, wherein the first burst of pulsed voltage waveforms comprises the first pulsed voltage waveform;
(b) halting, for a second period of time, the establishing of the first burst of pulsed voltage waveforms; and
repeating (a) and (b) at least one or more times.