JP7268932B1 - plasma injector - Google Patents

Abstract

A plasma injection apparatus capable of uniformly plasma-processing a surface to be processed in a narrow space is provided. SOLUTION: A plasma ejection port 18, a pair of discharge electrodes 5 and 6 facing each other in an opening of the plasma ejection port 18, gas passages 11 and 12 for supplying gas between the discharge electrodes 5 and 6, and the discharge electrode 5. , 6 is provided in the main body 10, and the gas passage includes a linear first passage, a flow opening 14a opened in the side surface near the tip of the first passage, and the flow passage. A second passage 12 extends from the port 14a in a direction intersecting the first passage 11 and reaches a plasma ejection port 18. In the second passage, the gas flow flowing out from the circulation port 14a is supplied to the plasma ejection. Gas guide means 19 and 15 are provided to guide the gas to the plasma ejection port 18 while correcting the direction of the flow along the axis L perpendicular to the opening surface at the center point O of the outlet. [Selection diagram] Fig. 1

Description

The present invention relates to a plasma injection device used for surface modification and the like.

2. Description of the Related Art Conventionally, there has been known a surface modification apparatus that modifies surface characteristics such as wettability of an object to be processed by irradiating plasma generated within the apparatus main body.
For example, in the apparatus of Patent Document 1, a discharge is generated between a pair of electrodes provided in a cylindrical apparatus main body, and the plasma generated by this discharge is blown out from the nozzle at the tip of the main body by a gas flow to the object to be processed. This is an apparatus for treating a necessary portion by jetting out toward the target and relatively moving the jetting port and the surface of the object to be processed.

There is also known an apparatus in which a main body is inserted into the object to be treated and plasma is jetted from an ejection port formed on the side surface of the main body when the surface to be treated is the inner surface of an annular object such as a cylinder. (See Patent Document 2).

JP 2006-277953 A JP-A-10-296446

As described above, in an apparatus for irradiating the inside of an annular object with plasma, for example, as shown in FIG. Inject plasma. The gas for ejecting plasma reaches the ejection port 2 after its flow direction is changed from the y-direction to the x-direction within the main body 1 .
Also, in order to allow the main body 1 to be inserted into a narrow space, the length of the gas passage 4 along the x direction must be set shorter than the length of the gas passage 3 along the y direction.

In this way, the gas supplied to the main body 1 flows from the relatively long gas passage 3 into the short gas passage 4 and changes direction, so that the momentum of the flow in the y direction remains until it is ejected from the ejection port 2. tends to be
As a result, the gas flow ejected from the ejection port 2 and directed toward the pair of discharge electrodes 5 and 6 is generally like the thick arrows shown in FIG. 6, and the spread of the plasma p is biased. That is, the center of the flow of the plasma p strikes the surface to be processed obliquely, and the density of the plasma applied to the surface to be processed is greatly uneven. As a result, there is a problem that the effect of plasma processing becomes uneven. In addition, in FIG. 6, the code|symbol 7 has shown the power supply.

SUMMARY OF THE INVENTION An object of the present invention is to provide a plasma injection apparatus capable of uniformly plasma-processing a narrow surface to be processed, such as the inside of an annular object.

A first invention comprises a plasma jet, a pair of discharge electrodes facing each other in an opening of the plasma jet, a gas passage for supplying gas between the pair of discharge electrodes, and a voltage being applied to the discharge electrodes. The main body includes a voltage applying means, and the gas passage includes a linear first passage in the main body, a flow port opened in the side surface near the tip of the first passage, and the flow port extending from the flow port to the first gas passage. a second passage extending in a direction intersecting the passage and reaching the plasma ejection port, the gas flow flowing out of the flow port being directed into the second passage at an opening surface at the center point of the plasma ejection port; gas guide means for directing the flow to the plasma outlet while correcting the direction of the flow along an axis perpendicular to the plasma outlet.

A second aspect of the present invention is a cylindrical member in which the gas guide means is provided continuously with the flow port, the inside communicates with the first passage, and the tip facing the plasma ejection port is closed. A plurality of communication small holes are formed in the side surface of the member and communicate between the inside and the outside of the cylindrical member, and the small communication holes extend the side surface of the cylindrical member on a plane passing through the axis. When the passage is divided into a surface on the side facing the upstream side and a surface on the non-opposing side, the surface on the facing side is arranged to have a larger opening area than the surface on the non-opposing side.

In a third aspect of the invention, a cylindrical case member is provided outside the cylindrical member along the inner wall of the second passage, and the communication small hole is provided between the outer wall of the cylindrical member and the inner wall of the case member. The tubular member and the case member are made of different materials.

According to the first invention, the first passage is made longer than the second passage, and the gas flow flowing out from the flow opening of the first passage into the second passage has a peculiarity in the direction along the first passage. You can fix it as well. The direction of the gas flow is modified in the second passage so that the plasma forms a distribution centered on the center point of the opening of the jet, thereby achieving uniform processing.
Also, the first passage is made sufficiently longer than the second passage, and the main body can be more easily inserted into a narrow space.

According to the second invention, by arranging the communication small holes in the cylindrical member, the momentum along the first passage is corrected, and the direction of the gas flow is directed along the axis perpendicular to the opening surface at the center point of the plasma jet nozzle. It can be corrected in a straight line.

According to the third invention, by changing the material, the natural frequency of the cylindrical member constituting the gas guide means and the natural frequency of the case member can be made different, thereby making it difficult for both members to resonate due to the gas flow. Therefore, noise generated by the gas flow can be reduced.

1 is a cross-sectional view of a body of an embodiment; FIG. FIG. 2 is a front view of the plasma jet of the embodiment. FIG. 3 is a cross-sectional view of the gas guide means of the embodiment. FIG. 4 is an image diagram of spread of plasma ejected from the plasma ejection port of the embodiment. FIG. 5 is a schematic diagram illustrating gas flow in a conventional plasma injection device. FIG. 6 is an image diagram of spread of plasma jetted from a conventional plasma apparatus.

[Embodiment]
An embodiment of the invention will be described below. FIG. 1 is a cross-sectional view of a main body of a plasma injection device according to an embodiment. 2 is a front view of the plasma jet of the embodiment, FIG. 3 is an enlarged cross-sectional view of the gas guide means, and FIG. 4 is an image diagram of spread of plasma jetted from the plasma jet of the embodiment.

The plasma injection device of this embodiment includes a first cylindrical member 13 having a first passage 11 therein, and a joint coupled to the tip thereof to change the direction of the first passage 11 to communicate with the second passage 12. A member 14 , a second cylindrical member 15 coupled to the joint member 14 , an electrode holder 16 coupled to the tip of the member 14 , and a cover 17 covering the tip surface of the electrode holder 16 .
The above members constitute the main body 10 of the plasma injection device of this embodiment. The material of each member may be resin, metal, or the like, and is not particularly limited. Also, a plurality of members may be integrally formed.

The first cylindrical member 13 has a linear first passage 11 inside and has a sufficient length in the y direction.
Here, the length direction of the first passage 11 is the y direction, the length direction of the second passage 12 is the x direction, and the direction perpendicular to the xy plane is the z direction.

The joint member 14 has a shape in which a flow port 14a is opened in a side wall of a tubular portion continuous to the tip end side of the first tubular member 13, that is, a side surface near the tip of the first passage 11. It is a member for communicating with the second passage 12 in the second cylindrical member 15 .
The second passage 12 is a gas passage that passes through the inside of the second cylindrical member 15 and the electrode holder 16 and is perpendicular to the first passage 11 at a portion downstream of the flow port 14 a in the flow of gas.

The second cylindrical member 15 is a member to which the proximal end is coupled to the flow port 14a side of the joint member 14 and the electrode holder 16 is coupled to the distal end side. The second cylindrical member 15 is a cylindrical case member provided along the inner wall of the second passage 12, and constitutes gas guide means together with a guide cylinder 19, which will be described later.

The electrode holder 16 is a cylindrical member having a second passage 12 formed in its center. 6 is installed. The discharge electrodes 5 and 6 are inserted into recesses formed in the sidewalls of the electrode holder 16 and fixed to the electrode holder 16 by fixing means (not shown). The discharge electrodes 5 and 6 are electrically connected to a power source 7 (see FIG. 4), which is a voltage applying means, through a side wall of the electrode holder 16 by connecting means (not shown).

A plasma ejection port 18 is formed in a cover 17 that covers the tip surface of the electrode holder 16 . As shown in FIG. 2, the plasma ejection port 18 is a slit-like opening having a length in the y direction. The electrodes 5 and 6 are sandwiched.

In addition, an axis L perpendicular to the opening surface of the plasma ejection port 18 at the opening center O, which is the central point of the plasma ejection port 18 , coincides with the central axis of the second passage 12 .
In this embodiment, the plasma ejection port 18 has a slit shape extending in the y direction, but the shape of the opening is not limited to this. For example, it may have a slit shape having a length in the z direction, or it may have a circular shape instead of a slit shape.

Inside the second cylinder member 15, a guide cylinder 19, which is a cylinder member constituting gas guide means, is provided. The guide cylinder 19 is composed of a cylinder portion 19a and a flange portion 19b. The guide cylinder 19 is made of synthetic resin or the like, but is made of a material different from that of the second cylinder member 15 .

The cylindrical portion 19a has a closed end facing the plasma ejection port 18 on the side opposite to the flange portion 19b, and has a plurality of small communication holes 19c formed in the side surface thereof. The guide tube 19 is provided inside the second tube member 15 so that a gap is formed between the outer peripheral surface of the tube portion 19 a and the inner peripheral surface of the second tube member 15 .
Therefore, the gas that has flowed out of the flow port 14a and into the cylindrical portion 19a flows out of the communication small hole 19c and is guided between the cylindrical portion 19a and the second cylindrical member 15. As shown in FIG. In this embodiment, the guide tube 19 and the second tube member 15 constitute gas guide means.

A plurality of small communication holes 19c are provided in the axial direction of the tubular portion 19a, and a plurality of small communication holes 19c are also provided in the circumferential direction. As shown in FIG. When the first passage 11 is divided into an A-side surface that faces the upstream side of the first passage 11 and a B-side surface that does not face the upstream side, the opposing A-side side surface is larger than the B-side side surface. It is arranged so that the opening area of 19c becomes large. In this embodiment, the opening areas of the individual small communicating holes 19c are made equal, and the small communicating holes 19c are arranged in three rows with a phase shift of 45° in the circumferential direction on the side surface on the A side above the plane S in FIG. 19c is formed, and on the side surface on the B side that is below the plane S, two rows of communicating small holes 19c are formed with phases shifted by 90° from each other. In this manner, the number of small communication holes 19c formed on the side surface on the A side is greater than the number of small communication holes 19c formed on the side surface on the B side. The plane S is an xz plane perpendicular to the y-direction axis.

[Action, effect, etc.]
In the plasma injection device of this embodiment, while supplying gas to the first passage 11, a voltage is applied to the discharge electrodes 5 and 6 to generate plasma. Plasma is ejected from the plasma ejection port 18 by the gas that has passed through the first passage 11 and the second passage 12, and the flow of this gas is controlled as follows.

The gas for ejecting plasma is supplied from the upstream side of the first passage 11, which is one end side of the first cylindrical member 13, and flows in the first passage 11 in the y direction. This gas flow flows into the guide cylinder 19 from the flow opening 14a of the joint member 14 and changes its direction in the x direction. However, since the gas flow has a habit of flowing in the y direction of the first passage 11 (because it has inertia in the y direction), it passes through the center of the second passage 12 immediately after flowing out from the flow port 14a. The flow is not along the axis L, and many components in the y direction remain. That is, the gas flow has a stronger tendency toward the B-side surface than the A-side surface facing the upstream side of the first passage 11 in the tubular portion 19 a of the guide tube 19 . Such a flow flows out from the communication small hole 19c of the cylinder portion 19a of the guide cylinder 19 to the outside thereof.

As described above, in the side surface of the cylindrical portion 19a, the A-side surface facing the upstream side of the first passage 11 has more communication small holes 19c than the B-side surface. Therefore, the gas flow that flows out from all the small communication holes 19c and passes between the cylindrical portion 19a and the second cylindrical member 15 has a component in the direction of the arrow y along the first passage 11 as a whole, which is directed to the above-mentioned A side. It will be corrected to be directed, resulting in flow along the axis L of the second passageway 12 .

In this way, the gas flow along the axis L of the second passage becomes a flow centered on the opening center O of the plasma ejection port 18, so the plasma ejected by this gas is, for example, the plasma p shown in FIG. It spreads out evenly in the y-direction from the center of the plasma jet 18 outward.
Therefore, such a plasma treatment can obtain a uniform treatment effect as compared with the case of irradiating uneven plasma as shown in FIG.

Further, since the guide cylinder 19 is provided in the second passage 12, the flow path between the cylinder portion 19a of the guide cylinder 19 and the second cylinder member 15 is narrowed, and the surrounding members are damaged by the high-speed gas flow. It may vibrate and generate noise. However, by forming the guide tube 19 and the second tube member 15 from appropriately selected different materials, resonance can be suppressed and noise can be reduced.

In addition, in the side surface of the cylindrical portion 19a of the guide tube 19, the opening area of the small communication hole 19c formed on the A side is made larger than the opening area of the small communication hole 19c formed on the B side. In addition to adjusting the number of small communication holes 19c as described above, the size of each small communication hole 19c may be varied.
Further, the shape of the guide tube 19 is not limited to the above embodiment, as long as the direction of the gas flow can be corrected along the axis L in the second passage 12 .
However, it is premised that the length of the second passage 12 cannot be set sufficiently long so that the direction of the gas flow is arranged naturally.

The plasma injection apparatus of the present invention can be applied to plasma processing in narrow spaces.

5, 6 discharge electrode 7 (voltage applying means) power supply 10 main body 11 first passage 12 second passage 13 first cylindrical member 14 joint member 14a flow port 15 (case member) second cylindrical member 16 electrode holder 17 cover 18 plasma jet Outlet 19 (Gas guide means) Guide cylinder 19c Communication small hole A Side facing the upstream side of the first passage B Side not facing the upstream side of the first passage O (Plasma ejection port) Opening center L Axis line S Passing through the axis line Plane

Claims (3)

a plasma jet;
a pair of discharge electrodes facing each other within the opening of the plasma jet;
a gas passage for supplying gas between the pair of discharge electrodes;
The main body is provided with a voltage applying means for applying a voltage to the discharge electrode,
The gas passage is
a linear first passageway within the body;
a circulation port opened in a side surface near the tip of the first passage;
a second passage extending from the flow port in a direction intersecting the first passage and reaching the plasma ejection port;
In the second passage,
A plasma injection device comprising gas guide means for guiding a gas flow flowing out of the flow port to the plasma ejection port while correcting the direction of the flow along an axis orthogonal to the opening surface at the center point of the plasma ejection port. The gas guide means is
a cylindrical member that is provided continuously with the flow port, has an interior that communicates with the first passage, and has a closed tip that faces the plasma ejection port;
A plurality of communication small holes formed on the side surface of the cylindrical member and communicating between the inside and the outside of the cylindrical member,
The small communicating hole is
When the side surface of the tubular member is divided into a surface facing the upstream side of the first passage and a surface not facing the upstream side of the first passage by a plane passing through the axis, the facing surface is the non-facing side. 2. The plasma injection device according to claim 1, wherein the opening area is arranged to be larger than the plane of . A cylindrical case member is provided outside the cylindrical member along the inner wall of the second passage,
A gas flow flowing out of the small communication hole is guided between the outer wall of the cylindrical member and the inner wall of the case member,
3. The plasma injection device according to claim 2, wherein the cylindrical member and the case member are made of different materials.

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