Balanced resonator source for plasma processing

Patent metadata

Field	Value
Publication number	US-12580153-B2
Application number	US-202418412042-A
Country	US
Kind code	B2
Filing date	Jan 12, 2024
Priority date	Jan 12, 2024
Publication date	Mar 17, 2026
Grant date	Mar 17, 2026

Abstract

According to an embodiment, a plasma processing system is proposed. The plasma processing system includes a plasma chamber; an RF source configured to generate a forward RF wave; an impedance matching circuit coupled to the RF source, the impedance matching circuit configured to provide matching for the RF source; a balun having unbalanced terminals coupled to the impedance matching circuit; and a resonant antenna configured to generate plasma within the plasma chamber, the resonant antenna being a spiral resonant antenna with an electrical length corresponding to a half-wavelength of a frequency of the forward RF wave, the resonant antenna comprising: a first tap along the spiral resonant antenna coupled to a first balanced terminal of the balun and a second tap along the spiral resonant antenna coupled to a second balanced terminal of the balun.

First claim

What is claimed is:

1 . A plasma processing system, comprising:
a plasma chamber; an RF source configured to generate a forward RF wave; an impedance matching circuit coupled to the RF source, the impedance matching circuit configured to provide matching for the RF source; a balun having unbalanced terminals coupled to the impedance matching circuit; and a resonant antenna configured to generate plasma within the plasma chamber, the resonant antenna being a single spiral resonant antenna with an electrical length corresponding to a half-wavelength of a frequency of the forward RF wave, the resonant antenna comprising:
a first tap along the single spiral resonant antenna coupled to a first balanced terminal of the balun, and
a second tap along the single spiral resonant antenna coupled to a second balanced terminal of the balun.

2 . The plasma processing system of claim 1 , wherein the impedance matching circuit comprises:
a first variable capacitor arranged between the balun and the RF source; a first inductor arranged between the first balanced terminal of the balun and the first tap; a second inductor arranged between the second balanced terminal of the balun and the second tap; and a second variable capacitor arranged between the first balanced terminal of the balun and the first tap, the second variable capacitor being in series with the first inductor.

3 . The plasma processing system of claim 1 , wherein the impedance matching circuit comprises:
a first variable capacitor arranged between the balun and the RF source; a first inductor arranged between the first balanced terminal of the balun and the first tap; a second inductor arranged between the second balanced terminal of the balun and the second tap; and a second variable capacitor arranged between the second balanced terminal of the balun and the second tap, the second variable capacitor being in series with the second inductor.

4 . The plasma processing system of claim 1 , wherein an operating frequency of the RF source is 27 megahertz (MHz).

5 . The plasma processing system of claim 1 , wherein the single spiral resonant antenna comprises:
a first portion having an electrical length corresponding to a quarter of a wavelength of a frequency of the forward RF wave, the first portion having a first end and a second end, the first end coupled to the first balanced terminal of the balun; a second portion having an electrical length corresponding to the quarter of the wavelength of the frequency of the forward RF wave, the second portion having a first end and a second end, the first end coupled to the second balanced terminal of the balun; and a conductive coupling structure electrically coupling the first end of the first portion to the first end of the second portion.

6 . The plasma processing system of claim 5 , wherein the first portion and the second portion are arranged in a symmetrically nested configuration having a same center point.

7 . The plasma processing system of claim 5 , wherein the second end of the first portion and the second end of the second portion are coupled to a reference ground.

8 . The plasma processing system of claim 5 , wherein the second end of the first portion and the second end of the second portion are floating.

9 . An apparatus for generating plasma in a plasma processing system, the apparatus comprising:
a plasma chamber; an RF source configured to generate a forward RF wave; an impedance matching circuit coupled to the RF source, the impedance matching circuit configured to provide matching for the RF source; a balun having unbalanced terminals coupled to the impedance matching circuit; a resonant antenna configured to generate plasma within the plasma chamber, the resonant antenna being a single spiral resonant antenna with an electrical length corresponding to a half-wavelength of a frequency of the forward RF wave, the resonant antenna comprising:
a first tap along the single spiral resonant antenna coupled to a first balanced terminal of the balun, and
a second tap along the single spiral resonant antenna coupled to a second balanced terminal of the balun;
a non-transitory memory storage comprising instructions; and a processor in communication with the non-transitory memory storage and coupled to the impedance matching circuit, wherein the instructions, when executed by the processor, cause the processor to provide a matching impedance between the RF source and the resonant antenna.

10 . The apparatus of claim 9 , wherein the instructions, when executed by the processor, cause the processor to generate a first current flowing into the single spiral resonant antenna to be equal to a second current flowing out of the single spiral resonant antenna.

11 . The apparatus of claim 9 , wherein the impedance matching circuit comprises:
a first variable capacitor arranged between the balun and the RF source; a first inductor arranged between the first balanced terminal of the balun and the first tap; a second inductor arranged between the second balanced terminal of the balun and the second tap; and a second variable capacitor arranged between the first balanced terminal of the balun and the first tap, the second variable capacitor being in series with the first inductor.

12 . The apparatus of claim 9 , wherein the impedance matching circuit comprises:
a first variable capacitor arranged between the balun and the RF source; a first inductor arranged between the first balanced terminal of the balun and the first tap; a second inductor arranged between the second balanced terminal of the balun and the second tap; and a second variable capacitor arranged between the second balanced terminal of the balun and the second tap, the second variable capacitor being in series with the second inductor.

13 . The apparatus of claim 9 , wherein the single spiral resonant antenna comprises:
a first portion having an electrical length corresponding to a quarter of a wavelength of a frequency of the forward RF wave, the first portion having a first end and a second end, the first end coupled to the first balanced terminal of the balun; a second portion having an electrical length corresponding to the quarter of the wavelength of the frequency of the forward RF wave, the second portion having a first end and a second end, the first end coupled to the second balanced terminal of the balun; and a conductive coupling structure electrically coupling the first end of the first portion to the first end of the second portion.

14 . The apparatus of claim 13 , wherein the first portion and the second portion are arranged in a symmetrically nested configuration having a same center point.

15 . The apparatus of claim 13 , wherein the second end of the first portion and the second end of the second portion are coupled to a reference ground.

16 . The apparatus of claim 13 , wherein the second end of the first portion and the second end of the second portion are floating.

17 . A plasma processing system, comprising:
a plasma chamber; an RF source configured to generate a forward RF wave; a balun having unbalanced terminals coupled to the RF source; an impedance matching circuit coupled to the RF source and the balun, the impedance matching circuit configured to provide matching for the RF source, the impedance matching circuit comprising:
a first variable capacitor arranged between the balun and the RF source, and
a first inductor, a second inductor, and a second variable capacitor arranged between the balun and the plas

Assignees

• Tokyo Electron Ltd

Inventors

• Wang Qiang
• Hummel Michael
• Chen Zhiying
• Ventzek Peter Lowell George
• Sridhar Shyam
• Ohata Mitsunori

Classifications

• H01J37/32183

  Matching circuits · CPC title

• H01J37/321

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

• H01J37/3211 Primary

  Antennas, e.g. particular shapes of coils · CPC title