# US 11,251,021 B2 · Mode-switching plasma systems and methods of operating thereof

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- Number: US 11,251,021 B2
- Document ID: US11251021B2
- Status: Granted
- Kind: B2
- Application number: 17/163,110
- Filed: 2021-01-29
- Published: 2021-05-20
- Granted: 2022-02-15
- Earliest claimed: 2019-07-24
- Assignees: Tokyo Electron Limited
- Applicants: Tokyo Electron Limited
- Inventors: Peter Ventzek; Alok Ranjan; Mitsunori Ohata; Michael Hummel
- Web page: https://patentgrep.com/patent/US11251021B2

## CPC

- H01J 37/32174: {Circuits specially adapted for controlling the RF discharge}
- H01J 37/32091: {the radio frequency energy being capacitively coupled to the plasma}
- H01J 37/321: {the radio frequency energy being inductively coupled to the plasma}
- H01J 37/32568: {Relative arrangement or disposition of electrodes; moving means}
- H01J 37/32605: {Removable or replaceable electrodes or electrode systems}
- H10P 14/24: using chemical vapour deposition [CVD]
- H10P 50/267: {using plasmas}
- H01J 2237/3321: CVD [Chemical Vapor Deposition]
- H01J 2237/3341: Reactive etching
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

A plasma processing apparatus includes a plasma processing chamber, a coil having an uncoiled length L disposed adjacent to the plasma processing chamber, and a plurality of retractable conductors each configured to make electrical contact with the coil in an extended position. A first tap position is located substantially at a distance L/2 measured from a first end along the coil, a second tap position neighboring the first tap position and located substantially at the distance L/2 measured from the first end along the coil, and a third tap position located substantially at the first end of the coil. A controller is configured to operate the plasma processing apparatus in a first operating mode to sustain an inductively coupled plasma and in a second operating mode to sustain a capacitively coupled plasma using subsets of the retractable conductors in the extended position.

## Claims

### Claim 1

A plasma processing apparatus comprising:
a plasma processing chamber;
a resonant coil disposed adjacent to the plasma processing chamber, the resonant coil comprising a length L measured along a coiled path of the resonant coil;
a plurality of retractable electrodes each configured to make electrical contact with the resonant coil in an extended position and to make no electrical contact with the resonant coil in a retracted position;
a first tap position located substantially at a distance L/2 measured from a first end along the resonant coil;
a second tap position neighboring the first tap position and located substantially at the distance L/2 measured from the first end along the resonant coil;
a third tap position located substantially at the first end of the resonant coil;
a controller configured to operate the plasma processing apparatus in a first operating mode and in a second operating mode using the plurality of retractable electrodes;
wherein in the first operating mode the plasma processing apparatus is configured to sustain an inductively coupled plasma using a first subset of the plurality of retractable electrodes in the extended position to couple a power source to the first tap position and to couple a reference potential to the second tap position; and
wherein in the second operating mode the plasma processing apparatus is configured to sustain a capacitively coupled plasma using a second subset of the plurality of retractable electrodes in the extended position to couple the power source to the first tap position and to couple the reference potential to the third tap position.

### Claim 2 (depends on 1)

The plasma processing apparatus of claim 1, wherein each of the plurality of retractable electrodes is disposed at a fixed position relative to the resonant coil.

### Claim 3 (depends on 1)

The plasma processing apparatus of claim 1, wherein the plurality of retractable electrodes comprises a laterally mobile retractable electrode configured to move in a direction perpendicular to a direction of extension of the laterally mobile retractable electrode.

### Claim 4 (depends on 3)

The plasma processing apparatus of claim 3, further comprising:
rails disposed adjacent to the resonant coil, the laterally mobile retractable electrode being configured to slide along the rails.

### Claim 5 (depends on 3)

The plasma processing apparatus of claim 3, wherein the controller is further configured to align the laterally mobile retractable electrode with the second tap position in the first operating mode and with the third tap position in the second operating mode.

### Claim 6 (depends on 1)

The plasma processing apparatus of claim 1, further comprising:
a fourth tap position located substantially at a second end of the resonant coil; and
wherein the plasma processing apparatus is further configured to sustain the capacitively coupled plasma in the second operating mode by using the second subset of the plurality of retractable electrodes in the extended position to couple the power source to the first tap position, to couple the reference potential to the third tap position, and to couple the reference potential to the fourth tap position in a half-wavelength resonator configuration.

### Claim 7 (depends on 1)

The plasma processing apparatus of claim 1, wherein the plasma processing apparatus is further configured to sustain the capacitively coupled plasma in the second operating mode by maintaining an open circuit at a second end of the resonant coil in a quarter-wavelength resonator configuration.

### Claim 8

A plasma processing apparatus comprising:
a plasma processing chamber;
a resonant coil disposed adjacent to the plasma processing chamber, the resonant coil comprising a length L measured along a coiled path of the resonant coil;
a power tap located substantially at a distance L/2 measured from a first end along the resonant coil;
a controller configured to switch between a first electrical path and a second electrical path by signaling one or more retractable electrodes to extend and make electrical contact with the resonant coil;
wherein the first electrical path couples the power tap to a power supply and couples a first position on the resonant coil to a reference potential node; and
wherein the second electrical path couples the power tap to the power supply and couples a second position on the resonant coil to the reference potential node.

### Claim 9 (depends on 8)

The plasma processing apparatus of claim 8, wherein:
the first position is located substantially at the distance L/2 measured from the first end along the resonant coil; and
the second position is located substantially at an end of the resonant coil.

### Claim 10 (depends on 8)

The plasma processing apparatus of claim 8, wherein the controller is further configured to:
operate the plasma processing apparatus in a first operating mode comprising sustaining an inductively coupled plasma by selecting the first electrical path; and
operate the plasma processing apparatus in a second operating mode comprising sustaining a capacitively coupled plasma by selecting the second electrical path.

### Claim 11 (depends on 8)

The plasma processing apparatus of claim 8, wherein the one or more retractable electrodes are each disposed at a fixed position relative to the resonant coil.

### Claim 12 (depends on 8)

The plasma processing apparatus of claim 8, wherein the one or more retractable electrodes comprises a laterally mobile retractable electrode configured to move in a direction perpendicular to a direction of extension of the laterally mobile retractable electrode.

### Claim 13 (depends on 12)

The plasma processing apparatus of claim 12, wherein the controller is further configured to align the laterally mobile retractable electrode with the first position to form the first electrical path and with the second position to form the second electrical path.

### Claim 14

A method of plasma processing, the method comprising:
sustaining a first plasma in a plasma processing chamber during a first operational mode by extending a first retractable electrode to make electrical contact with a resonant coil to couple a first contact region of the resonant coil to a reference potential;
switching from the first operational mode to a second operational mode using a controller by retracting the first retractable electrode from the first contact region and extending the first retractable electrode or a second retractable electrode to make electrical contact with the resonant coil to couple a second contact region of the resonant coil to the reference potential; and
sustaining a second plasma in the plasma processing chamber during the second operation mode.

### Claim 15 (depends on 14)

The method of claim 14, wherein the first plasma is an inductively coupled plasma, and wherein the second plasma is a capacitively coupled plasma.

### Claim 16 (depends on 14)

The method of claim 14, wherein:
switching from the first operational mode to the second operational mode comprises
retracting the first retractable electrode from the first contact region, and
extending the second retractable electrode to make electrical contact with the resonant coil to couple the second contact region of the resonant coil to the reference potential; and
the first retractable electrode and the second retractable electrode are each at a fixed position relative to the resonant coil.

### Claim 17 (depends on 14)

The method of claim 14, wherein switching from the first operational mode to the second operational mode comprises:
retracting the first retractable electrode from the first contact region;
moving the first retractable electrode in a direction perpendicular to a direction of extension of the first retractable electrode to align the first retractable electrode with the second contact region of the resonant coil; and
extending the first retractable electrode to make electrical contact with the resonant coil to couple the second contact region of the resonant coil to the reference potential.

### Claim 18 (depends on 14)

The method of claim 14, wherein sustaining the first plasma during the first operational mode further comprises:
supplying power to a power tap located substantially at a midpoint of the resonant coil; and
extending the first retractable electrode to make electrical contact with the resonant coil to couple the first contact region of the resonant coil to the reference potential, the first contact region being located substantially at the midpoint of the resonant coil and neighboring the power tap.

### Claim 19 (depends on 14)

The method of claim 14, wherein sustaining the second plasma during the second operational mode comprises:
supplying power to a power tap located substantially at a midpoint of the resonant coil; and
extending the first retractable electrode or the second retractable electrode to make electrical contact with the resonant coil to couple the second contact region of the resonant coil to the reference potential, the second contact region being located substantially at a first end of the resonant coil.

### Claim 20 (depends on 19)

The method of claim 19, wherein sustaining the second plasma during the second operational mode further comprises:
extending a third retractable electrode to make electrical contact with the resonant coil to couple a third contact region of the resonant coil to the reference potential, the third contact region being located substantially at a second end of the resonant coil.