# US 2020/0286715 A1 · Plasma processing apparatus, plasma processing method, and ecr height monitor

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- Number: US 2020/0286715 A1
- Document ID: US20200286715A1
- Status: Published application
- Kind: A1
- Application number: 16/640,443
- Filed: 2019-03-06
- Published: 2020-09-10
- Earliest claimed: 2019-03-06
- Assignees: Hitachi High-Technologies Corporation
- Applicants: Hitachi High-Technologies Corporation
- Inventors: Norihiko IKEDA; Naoki YASUI; Kazuya YAMADA
- Web page: https://patentgrep.com/patent/US20200286715A1

## CPC

- H01J 37/32678: {Electron cyclotron resonance}
- H01J 37/32201: {Generating means}
- H01J 37/32311: {Circuits specially adapted for controlling the microwave discharge}
- H01J 37/32935: {Monitoring and controlling tubes by information coming from the object and/or discharge}
- H05H 1/46: using applied electromagnetic fields, e.g. high frequency or microwave energy (H05H1/26 takes precedence)
- H10P 50/242: {of Group IV materials}
- H01J 2237/3341: Reactive etching
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)
- H05H: PLASMA TECHNIQUE (apparatus or processes specially adapted for producing X-rays H05G2/00); PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

A plasma processing apparatus includes a processing chamber 101 where a wafer 114 is processed using plasma 111, a radio frequency power supply 106 configured to supply a radio frequency power for generating the plasma 111, a mechanism configured to form a magnetic field for forming ECR and to control a magnetic flux density thereof, and a sample stage 113 on which the wafer 114 is placed. The plasma processing apparatus further includes a control unit 107 configured to, based on image data of the plasma 111, monitor a height of ECR which is electron cyclotron resonance generated by an interaction between the radio frequency power and the magnetic field, and to control a frequency of the radio frequency power such that the monitored ECR height becomes a predetermined height.

## Claims

### Claim 1

A plasma processing apparatus comprising:
a processing chamber where a sample is processed using plasma; a radio frequency power supply configured to supply a radio frequency power for generating the plasma;
a sample stage on which the sample is placed;
a magnetic field forming mechanism configured to form a magnetic field in the processing chamber; and
a control unit configured to, based on image data of the plasma, monitor a height of ECR which is electron cyclotron resonance generated by an interaction between the radio frequency power and the magnetic field, and to control a frequency of the radio frequency power such that the monitored ECR height becomes a predetermined height.

### Claim 2 (depends on 1)

The plasma processing apparatus according to claim 1, further comprising:
a monitor mechanism configured to monitor the ECR height, wherein
the monitor mechanism includes a camera configured to image the plasma from a horizontal direction or an oblique direction, a first spectrometer configured to obtain an light emission intensity of the plasma from above an ECR plane, and a second spectrometer configured to obtain the light emission intensity of the plasma from below the ECR plane.

### Claim 3 (depends on 1)

The plasma processing apparatus according to claim 1, wherein
the control unit determines the ECR height by using the image data of the plasma and a light emission intensity distribution of the plasma in a height direction of the processing chamber.

### Claim 4 (depends on 1)

The plasma processing apparatus according to claim 1, wherein
the magnetic field forming mechanism includes a coil configured to form the magnetic field, and
the control unit is configured to control the frequency of the radio frequency power so as to correct a variation of the ECR height, due to a response delay of a current flowing through the coil, with respect to a predetermined value.

### Claim 5 (depends on 1)

The plasma processing apparatus according to claim 1, wherein
the radio frequency power supply is a solid microwave power supply.

### Claim 6

An ECR height monitor configured to monitor a height of ECR which is electron cyclotron resonance generated by an interaction between a radio frequency power for generating plasma and a magnetic field, wherein
the ECR height is monitored by using image data of the plasma and a light emission intensity distribution of the plasma in a height direction of a processing chamber where the plasma is generated.

### Claim 7

A plasma processing method for processing a sample by using plasma, the plasma processing method comprising:
a step of monitoring a height of ECR which is electron cyclotron resonance generated by an interaction between a radio frequency power for generating the plasma and a magnetic field based on image data of the plasma; and
a step of controlling a frequency of the radio frequency power such that the monitored ECR height becomes a predetermined height.

### Claim 8 (depends on 7)

The plasma processing method according to claim 7, wherein
when the frequency of the radio frequency power is changed by a predetermined amount, a value of a current flowing through a coil for forming the magnetic field is controlled such that the ECR height is equal to or higher than the predetermined height.

### Claim 9 (depends on 8)

The plasma processing method according to claim 8, wherein
when switching a step in which a plasma processing condition is configured, the current flowing through the coil is set to the controlled current value before switching the step.