# US 10,246,771 B2 · Film forming method and plasma chemical vapor deposition apparatus

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- Number: US 10,246,771 B2
- Document ID: US10246771B2
- Status: Granted
- Kind: B2
- Application number: 15/442,121
- Filed: 2017-02-24
- Published: 2017-09-07
- Granted: 2019-04-02
- Earliest claimed: 2016-03-01
- Assignees: Toyota Jidosha Kabushiki Kaisha
- Applicants: Toyota Jidosha Kabushiki Kaisha
- Inventors: Kazutaka Tachibana; Takayasu Sato; Yoji Sato; Hiromichi Nakata; Kazuyoshi Manabe; Seiji Okamura; Izuru Yamamoto
- Web page: https://patentgrep.com/patent/US10246771B2

## CPC

- C23C 16/26: Deposition of carbon only
- C23C 16/511: using microwave discharges
- C23C 16/52: Controlling or regulating the coating process {(C23C16/45557, C23C16/279 take precedence)}
- H05H 1/46: using applied electromagnetic fields, e.g. high frequency or microwave energy (H05H1/26 takes precedence)
- H05H 1/4622: {using waveguides}
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)
- 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

## Abstract

A PCVD apparatus includes a waveguide member which supports the workpiece with a portion of the waveguide member positioned in a reactor and causes microwaves output from a high-frequency output device to propagate to the workpiece. In a process of gradually increasing an intensity of the microwaves propagating to the workpiece through the waveguide member from “0”, the intensity of the microwaves output from the high-frequency output device when step-up of a bias current of the workpiece occurs is referred to as a first intensity, and in a process of gradually increasing the intensity of the microwaves from the first intensity, the intensity of the microwaves when step-up of the bias current occurs again is referred to as a second intensity. During film formation, the microwaves having an intensity of higher than the first intensity and lower than the second intensity are output from the high-frequency output device.

## Claims

### Claim 1

A method of forming a diamond-like carbon film on a workpiece installed in a reactor of a plasma chemical vapor deposition (PCVD) apparatus, wherein the PCVD apparatus includes:
(i) a microwave output device which outputs microwaves, and
(ii) a waveguide member which extends to an inside of the reactor from an outside of the reactor, wherein the waveguide member supports the workpiece with a portion of the waveguide member positioned in the reactor, and the waveguide member is configured to propagate the microwaves from the microwave output device to the workpiece,
the method comprising:
supplying a hydrocarbon gas into the reactor of the PCVD apparatus;
outputting microwaves having an intensity of higher than a first intensity and lower than a second intensity from the microwave output device, through the waveguide member and to the workpiece to decompose the hydrocarbon gas into a plasma and to form the diamond-like carbon film on the workpiece, wherein:
the first intensity and the second intensity are defined by a method comprising:
supplying the hydrocarbon gas into the reactor of the PCVD apparatus;
outputting microwaves having a third intensity starting from “0” intensity from the microwave output device, through the waveguide member and to the workpiece;
increasing the third intensity of microwaves outputted from the microwave output device;
defining the first intensity to be the third intensity when a first step-up of a bias current of the workpiece occurs;
further increasing the third intensity of microwaves outputted from the microwave output device;
defining the second intensity to be the third intensity when a second step-up of the bias current of the workpiece occurs;
wherein the first step-up and the second step-up of the bias current are each a sudden discontinuous increase in the bias current of the workpiece, and
wherein the hydrocarbon gas: (i) is acetylene or a hydrocarbon gas having two or more carbon atoms and two or more hydrogen atoms, and (ii) causes step-up of the bias current of the workpiece only twice.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the outputting of the microwaves having an intensity of higher than the first intensity and lower than the second intensity from the microwave output device, further comprises supplying a DC current to the workpiece to charge the workpiece with a negative charge.

### Claim 3 (depends on 2)

The method according to claim 2, wherein
the waveguide member of the plasma chemical vapor deposition apparatus has an elongated first conductor of which one end is positioned in the reactor to support the workpiece with the one end, and a cylindrical second conductor which is positioned on an outer peripheral side of the first conductor and is disposed coaxially with the first conductor, and
the supply of DC current to the workpiece further comprises supplying a DC voltage to the first conductor which charges the workpiece with a negative charge, and causes the microwaves output from the microwave output device to flow through a surface of the first conductor.

### Claim 4 (depends on 1)

The method according to claim 1, wherein the intensity of the microwaves is higher than an intermediate value between the first intensity and the second intensity and lower than the second intensity.