# US 2025/0218751 A1 · Real-time measurement of microwave resonators as plasma diagnostics for process monitoring

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- Number: US 2025/0218751 A1
- Document ID: US20250218751A1
- Status: Published application
- Kind: A1
- Application number: 18/401,112
- Filed: 2023-12-29
- Published: 2025-07-03
- Earliest claimed: 2023-12-29
- Assignees: Applied Materials, Inc.
- Applicants: Applied Materials, Inc.
- Inventors: DAVID PETERSON; DAVID COUMOU
- Web page: https://patentgrep.com/patent/US20250218751A1

## CPC

- H01J 37/32935: {Monitoring and controlling tubes by information coming from the object and/or discharge}
- G01N 22/00: Investigating or analysing materials by the use of microwaves or radio waves, i.e. electromagnetic waves with a wavelength of one millimetre or more (G01N3/00 - G01N17/00, G01N24/00 take precedence)
- H01J 37/32917: {Plasma diagnostics}
- H01J 37/32192: {Microwave generated discharge (H01J37/32357, H01J37/32366, H01J37/32394, H01J37/32403 take precedence)}
- H01J 2237/24564: Measurements of electric or magnetic variables, e.g. voltage, current, frequency
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)

## Abstract

Embodiments disclosed herein include an apparatus that comprises a board with a signal generator for generating chirped signals on the board. In an embodiment, a first mixer is on the board and electrically coupled to the signal generator, and a circulator is on the board. In an embodiment, the circulator comprises a first port that is electrically coupled to the mixer, a second port that is electrically coupled to a connector, and a third port. In an embodiment, a second mixer is on the board and electrically coupled to the third port of the circulator. In an embodiment, an analog to digital converter (ADC) is on the board and electrically coupled to the second mixer.

## Claims

### Claim 1

An apparatus, comprising:
a board;
a signal generator for generating chirped signals on the board;
a first mixer on the board and electrically coupled to the signal generator;
a circulator on the board, wherein the circulator comprises a first port that is electrically coupled to the mixer, a second port that is electrically coupled to a connector, and a third port;
a second mixer on the board and electrically coupled to the third port of the circulator; and
an analog to digital converter (ADC) on the board and electrically coupled to the second mixer.

### Claim 2 (depends on 1)

The apparatus of claim 1, further comprising:
a phase locked loop (PLL) synthesizer on the board and electrically coupled between the first mixer and the second mixer.

### Claim 3 (depends on 1)

The apparatus of claim 1, wherein the signal generator is configured to generate the chirped signal with a pulse length up to 100 ms.

### Claim 4 (depends on 1)

The apparatus of claim 1, wherein the chirped signal is a linear chirp, an exponential chirp, or a hyperbolic chirp.

### Claim 5 (depends on 1)

The apparatus of claim 1, wherein the chirped signal has a frequency range with a low frequency up to 0.01 GHz and a high frequency up to 10.0 GHz.

### Claim 6 (depends on 1)

The apparatus of claim 1, wherein the first mixer is configured to up-convert a signal, and wherein the second mixer is configured to down-convert the signal.

### Claim 7 (depends on 1)

The apparatus of claim 1, further comprising:
a low pass filter on the board and electrically coupled between the signal generator and the first mixer and/or a high pass filter on the board and electrically coupled between the first mixer and the circulator.

### Claim 8

A method for monitoring a plasma property in real time, comprising:
generating a chirped signal with a first frequency range;
converting the first frequency range to a second frequency range that is higher than the first frequency range;
providing the chirped signal to a resonator for interaction with a plasma, wherein a plasma modified resonant frequency of the resonator is measured by a reflected chirped carrier signal;
converting the reflected signal to a third frequency range that is lower than the second frequency range;
extracting a plasma property from the reflected signal.

### Claim 9 (depends on 8)

The method of claim 8, wherein the chirped signal comprises a pulse length that is up to 100 ms.

### Claim 10 (depends on 8)

The method of claim 8, wherein the plasma property is a plasma electron density and/or an electron temperature.

### Claim 11 (depends on 8)

The method of claim 8, wherein the resonator is a microwave resonator probe.

### Claim 12 (depends on 8)

The method of claim 8, wherein the first frequency range has a low frequency up to 0.01 GHz and a high frequency up to 1.0 GHz, and wherein the second frequency range has a low frequency up to 9.0 GHz and high frequency up to 11.0 GHz.

### Claim 13 (depends on 8)

The method of claim 8, wherein the chirped signal is one chirp of a series of chirps, and wherein each chirp is spaced by a duration up to 10 μs.

### Claim 14 (depends on 8)

The method of claim 8, wherein the chirped signal is a linear chirp, an exponential chirp, or a hyperbolic chirp.

### Claim 15

A tool, comprising:
a chamber suitable for generating a plasma;
a pedestal within the chamber for supporting a substrate; and
a sensor at least partially within the chamber for measuring plasma properties, wherein the sensor comprises:
a resonator or transmission line; and
RF circuitry coupled to the resonator, wherein the RF circuitry is configured to generate chirped pulses that are fed to the resonator.

### Claim 16 (depends on 15)

The tool of claim 15, wherein the resonator is provided along a wall of the chamber, and wherein the RF circuitry is coupled to the resonator through a link that passes through the wall of the chamber.

### Claim 17 (depends on 15)

The tool of claim 15, wherein the sensor is integrated into a substrate that is supported on the pedestal.

### Claim 18 (depends on 15)

The tool of claim 15, wherein the RF circuitry comprises:
a board;
a direct digital synthesizer (DDS) on the board;
a first mixer on the board and electrically coupled to the DDS;
a circulator on the board, wherein the circulator comprises a first port that is electrically coupled to the mixer, a second port that is electrically coupled to a connector, and a third port;
a second mixer on the board and electrically coupled to the third port of the circulator; and
an analog to digital converter (ADC) on the board and electrically coupled to the second mixer.

### Claim 19 (depends on 15)

The tool of claim 15, wherein the sensor is configured to measure a frequency of the plasma generated within the chamber using the transmission line or a resonant frequency shift of the resonator induced by interaction with a plasma.

### Claim 20 (depends on 19)

The tool of claim 19, wherein the frequency of the plasma or the resonant frequency shift are used to measure plasma properties.