Variable output impedance RF generator

Patent metadata

Field	Value
Publication number	US-11670484-B2
Application number	US-202117231931-A
Country	US
Kind code	B2
Filing date	Apr 15, 2021
Priority date	Nov 30, 2018
Publication date	Jun 6, 2023
Grant date	Jun 6, 2023

Abstract

Various RF plasma systems are disclosed that do not require a matching network. In some embodiments, the RF plasma system includes an energy storage capacitor; a switching circuit coupled with the energy storage capacitor, the switching circuit producing a plurality of pulses with a pulse amplitude and a pulse frequency, the pulse amplitude being greater than 100 volts; a resonant circuit coupled with the switching circuit. In some embodiments, the resonant circuit includes: a transformer having a primary side and a secondary side; and at least one of a capacitor, an inductor, and a resistor. In some embodiments, the resonant circuit having a resonant frequency substantially equal to the pulse frequency, and the resonant circuit increases the pulse amplitude to a voltage greater than 2 kV.

First claim

That which is claimed:

1. An RF system comprising:
an energy storage capacitor;
a switching circuit coupled with the energy storage capacitor, the switching circuit producing a plurality of pulses with a pulse amplitude and a pulse frequency, the pulse amplitude being greater than 100 volts;
a transformer having a primary side and a secondary side, the transformer coupled with the switching circuit; and
an energy recovery circuit coupled with the energy storage capacitor and the secondary side of the transformer.

2. The RF system according to claim 1 , further comprising:
a resonant circuit, wherein the resonant circuit comprises a circuit element selected from the group consisting of a capacitor, an inductor, and a resistor;
wherein the resonant circuit has a resonant frequency substantially equal to the pulse frequency, and the resonant circuit increases the pulse amplitude to a voltage greater than 1 kV; and
a plasma chamber coupled with the resonant circuit.

3. The RF system according to claim 1 , wherein the switching circuit comprises either a full-bridge driver or a half-bridge driver, and wherein the energy recovery circuit comprises a diode and an inductor.

4. The RF system according to claim 1 , wherein the resonant circuit comprises an inductor, and the resonant frequency comprises

f

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L
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(
C
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,

where the inductance L includes any stray inductance of the transformer and the inductance of the inductor, and the capacitance C includes any stray capacitance of the transformer.

5. The RF system according to claim 1 , wherein the resonant circuit comprises a capacitor, and the resonant frequency comprises

f

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e
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(
L
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C
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,

where the inductance L includes any stray inductance of the transformer, and the capacitance C includes any stray capacitance of the transformer and the capacitance of the capacitor.

6. An RF plasma system comprising:
an RF driver in a half-bridge or full-bridge configuration, the RF driver comprising a plurality of switches producing a plurality of pulses with a pulse amplitude and a pulse frequency, the pulse amplitude being greater than 100 volts;
a transformer coupled with the RF driver;
an energy recovery circuit coupled with the transformer;
a bias compensation circuit coupled with the energy recovery circuit;
and
a plasma chamber coupled with the bias-compensation circuit.

7. The RF plasma system according to claim 6 , further comprising a resonant circuit coupled with the RF driver, the resonant circuit having a resonant frequency substantially equal to the pulse frequency and the resonant circuit increases the amplitude of the plurality of pulses to a voltage greater than 1 kV.

8. The RF plasma system according to claim 6 , wherein each of the plurality of switches is coupled in parallel with a respective diode.

9. The RF plasma system according to claim 6 , further comprising a half-wave rectifier coupled with the energy recovery circuit.

10. The RF plasma system according to claim 9 , wherein the half-wave rectifier comprises a blocking diode.

11. The RF plasma system according to claim 6 , wherein either or both the inductance (L) and/or the capacitance (C) of the transformer determine the resonant frequency according to:

f

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⁢
e
⁢
s
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o
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n
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n
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t

≈

1

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(
L
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(
C
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.

12. The RF plasma system according to claim 6 , wherein the resonant frequency comprises

f

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L

Assignees

• Eagle Harbor Tech Inc

Inventors

• Prager James
• Ziemba Timothy

Classifications

• H01J37/32128 Primary

  using particular waveforms, e.g. polarised waves · CPC title

• H01J37/321

  the radio frequency energy being inductively coupled to the plasma · CPC title

• H03K3/36

  by the use, as active elements, of semiconductors, not otherwise provided for · CPC title

• H03K3/57

  the switching device being a semiconductor device · CPC title

• H01J37/32183 Primary

  Matching circuits · CPC title