US-12626891-B2 - Plasma processing apparatus

US12626891B2US 12626891 B2US12626891 B2US 12626891B2US-12626891-B2

Abstract

A plasma processing apparatus includes: an inner electrode; an electrode holder; an outer electrode; an insulating member that surrounds the inner electrode and the electrode holder; a fin member for forming a swirling flow around the inner electrode by causing a process gas supplied to an inner side of the insulating member to swirl; and a nozzle that blows the swirling flow converted into a plasma state. The insulating member is directly or indirectly secured to the outer electrode, and the fin member is secured to the electrode holder while being spaced from the inner electrode, and is in contact with an inner circumferential surface of the insulating member.

Inventors

Ryoji TAMAKI
Hayato NOTOMI
Shigeki Amadatsu
Shinichi Hasegawa

Assignees

DAIHEN CORPORATION

Dates

Publication Date: 20260512
Application Date: 20240613
Priority Date: 20230620

Claims (6)

1 . A plasma processing apparatus comprising: an inner electrode that receives application of a voltage; an electrode holder that surrounds and holds the inner electrode; an outer electrode formed in a tubular shape, the outer electrode surrounding the inner electrode and the electrode holder; an insulating member arranged between the inner electrode and the outer electrode and between the electrode holder and the outer electrode, the insulating member surrounding the inner electrode and the electrode holder; a fin member for forming a swirling flow around the inner electrode by causing a process gas supplied to an inner side of the insulating member to swirl; and a nozzle that blows the swirling flow converted into a plasma state, wherein the insulating member is directly or indirectly secured to the outer electrode, and the fin member is secured to the electrode holder while being spaced from the inner electrode, and is in contact with an inner circumferential surface of the insulating member.
2 . The plasma processing apparatus according to claim 1 , wherein the electrode holder has a contact surface in contact with the inner circumferential surface of the insulating member, and a flow path forming surface spaced from the inner circumferential surface of the insulating member, the flow path forming surface forming a flow path of the process gas together with the inner circumferential surface of the insulating member.
3 . The plasma processing apparatus according to claim 2 , wherein the electrode holder has a holding portion that holds the fin member, and the holding portion is formed downstream of the flow path forming surface in a flow direction of the process gas.
4 . The plasma processing apparatus according to claim 1 , further comprising: a gas supply unit provided at a position spaced from the outer electrode in a direction parallel to a central axis of the inner electrode, the gas supply unit supplying the process gas; and an intermediate member interposed between the gas supply unit and the outer electrode, wherein the insulating member has a base end portion secured to the intermediate member, and the insulating member has a tip end portion secured to the nozzle.
5 . The plasma processing apparatus according to claim 1 , wherein a length between the fin member and a tip end of the inner electrode is more than or equal to three times and less than or equal to ten times as long as an inner diameter of the insulating member.
6 . The plasma processing apparatus according to claim 1 , wherein the fin member has an inner circumferential surface which is spaced from the inner electrode.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This nonprovisional application is based on Japanese Patent Application No. 2023-100803 filed on Jun. 20, 2023 with the Japan Patent Office, the entire contents of which are hereby incorporated by reference. BACKGROUND OF THE INVENTION Field of the Invention The present disclosure relates to a plasma processing apparatus. Description of the Background Art A plasma torch capable of causing a process gas to swirl is known, as is found in Japanese Utility Model Laying-Open No. 6-54471, for example. SUMMARY OF THE INVENTION In the plasma processing apparatus described in Japanese Utility Model Laying-Open No. 6-54471, a fin member is in contact with an electrode and a nozzle. Therefore, the fin member may suffer damage due to heat from the electrode and the nozzle. An object of the present disclosure is to provide a plasma processing apparatus capable of reducing damage to a fin member. A plasma processing apparatus according to one aspect of the present disclosure includes: an inner electrode that receives application of a voltage; an electrode holder that holds the inner electrode; an outer electrode formed in a tubular shape, the outer electrode surrounding the inner electrode and the electrode holder; an insulating member arranged between the inner electrode and the outer electrode and between the electrode holder and the outer electrode, the insulating member surrounding the inner electrode and the electrode holder; a fin member for forming a swirling flow around the inner electrode by causing a process gas supplied to an inner side of the insulating member to swirl; and a nozzle that blows the swirling flow converted into a plasma state, wherein the insulating member is directly or indirectly secured to the outer electrode, and the fin member is secured to the electrode holder while being spaced from the inner electrode, and is in contact with an inner circumferential surface of the insulating member. The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional perspective view of a plasma processing apparatus in one embodiment of the present disclosure. FIG. 2 is a cross-sectional view showing a relationship among an inner electrode, an electrode holder and an insulating member. FIG. 3 is an exploded perspective view of the electrode holder and a fin member. DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present disclosure will be described with reference to the drawings. In the drawings referenced below, the same or corresponding members are denoted by the same numerals. FIG. 1 is a cross-sectional perspective view of a plasma processing apparatus in one embodiment of the present disclosure. This plasma processing apparatus 1 is suitably used for surface modification of a workpiece. As shown in FIG. 1, plasma processing apparatus 1 includes an inner electrode 100, an electrode holder 200, an outer electrode 300, an insulating member 400, a fin member 500, a nozzle 600, a gas supply unit 700, and an intermediate member 750. Inner electrode 100 has a linearly extending shape. Inner electrode 100 is made of tungsten, for example. A voltage is applied to inner electrode 100 from a power supply which is not shown. Electrode holder 200 holds inner electrode 100. Electrode holder 200 is made of copper, for example. Electrode holder 200 will be detailed later herein. Outer electrode 300 is formed in a tubular shape. More specifically, outer electrode 300 is formed in a cylindrical shape. Outer electrode 300 surrounds inner electrode 100 and electrode holder 200. Insulating member 400 is arranged between inner electrode 100 and outer electrode 300 and between electrode holder 200 and outer electrode 300. Insulating member 400 surrounds inner electrode 100 and electrode holder 200. Insulating member 400 is formed in a cylindrical shape. Insulating member 400 defines a position where plasma is generated between inner electrode 100 and outer electrode 300. As shown in FIG. 1, the position of a tip end of insulating member 400 is set to expose a tip end 101 of inner electrode 100 from this tip end. In other words, a process gas is converted into a plasma state in the vicinity of tip end 101 of inner electrode 100 due to a discharge phenomenon that occurs between the vicinity of tip end 101 and outer electrode 300. Electrode holder 200 is now detailed. As shown in FIGS. 1 to 3, electrode holder 200 has an outer holder 210, a first inner holder 220, and a second inner holder 230. Outer holder 210 surrounds inner electrode 100. As shown in FIG. 1, an inner circumferential surface of outer holder 210 is provided with a reduced-diameter portion 211 that is gradually reduced in diameter toward a tip end (downstream side in a flow dir