JPS61218816A - Gaseous phase excitation device - Google Patents

Abstract

PURPOSE:To enable a carrier gas and a source gas to be uniformly mixed in a pipe by passing both the gases through an electrode composed of double pipes of a given length. CONSTITUTION:A barlike second electrode 9b is provided in a pipelike first electrode 9a. A carrier gas and a source gas are supplied into the first electrode 9a. A discharge is induced between the first and second electrodes 9a, 9b. A DC glow discharge or a high frequency glow discharge method is used as a gaseous phase excitation method usable in this case. Further, a perforated pipe is used as the second electrode 9b provided in the first electrode 9a and a carrier gas and a source gas are supplied into the first and second electrodes 9a and 9b, respectively. This construction secure a uniform mixture of the carrier gas and the source gas.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a gas phase excitation device used in a flow control device for a particulate flow, which is used as a means for transporting or spraying particulates.

In this document, fine particles refer to atoms, molecules, ultrafine particles, and general fine particles. Here, ultrafine particles are, for example,
Evaporation method in gas, plasma evaporation method using gas phase reaction,
Obtained by gas phase chemical reaction method, colloidal precipitation method, solution spray pyrolysis method, etc. using liquid phase reaction,
Refers to ultrafine particles (generally 0.5 p, m or less).

General fine particles refer to fine particles obtained by a general method such as mechanical crushing or precipitation treatment. Also, a beam is a jet whose cross-sectional area is almost constant in the flow direction.
Its cross-sectional shape does not matter.

[Prior Art] Conventionally, a gas phase excitation device used for generating and activating fine particles supplies a carrier gas and a raw material gas between two parallel electrodes facing each other, and discharges between the two electrodes. Met.

[Problems to be solved by the invention] However, in such conventional devices, it is difficult to uniformly mix the carrier gas and the raw material gas, and the discharge between parallel electrodes is difficult to utilize due to gas diffusion, etc. It was inefficient.

The present invention was made to solve the above-mentioned drawbacks of the prior art, and an object of the present invention is to provide a gas phase excitation device that can efficiently generate and activate fine particles.

Means for Solving Problem L] The basic principle of the present invention will be explained with reference to FIG. 1 corresponding to an embodiment. In FIG. 1, a rod-shaped second electrode 8b is provided at the center of a cylindrical first electrode 9a, and a carrier gas and source gas are supplied from one end of the device 9.

The structure is such that discharge occurs between the first and second electrodes.

[Operation] Since both the gear gas and the raw material gas pass through the pipe, the gases can be mixed more thoroughly than in the past.

In addition, since the discharge occurs within the pipe, it is possible to efficiently generate and activate the particles without unnecessarily diffusing the gas.

[Example] Fig. 2 is a schematic diagram of an example in which the gas phase excitation device according to the present invention is used in a film forming device using ultrafine particles, in which 1 is a contraction/expansion nozzle, 3 is an upstream chamber, and 4a is First downstream chamber, 4b
9 is a second downstream chamber, and 9 is a gas phase excitation device.

The upstream chamber 3 and the first downstream chamber 4a are configured as an integrated unit, and the first downstream chamber 4a is equipped with a skimmer 7, a gate valve 8, and a second downstream chamber 4, which are also each unitized.
b are sequentially connected to each other so as to be connectable and separable via flanges having a common diameter (hereinafter referred to as "common flanges"). Upstream chamber 3, first downstream chamber 4a and second downstream chamber 4
b is maintained at a high degree of vacuum in stages from the upstream chamber 3 to the second downstream chamber 4b by an exhaust system to be described later.

A gas phase excitation device 9 is attached to one side of the upstream chamber 3 via a common flange. This gas phase excitation device 9 generates active ultrafine particles using plasma, and sends out the ultrafine particles together with a carrier gas such as hydrogen, helium, argon, nitrogen, etc. to a contraction/expansion nozzle l located on the opposite side. It is. In order to prevent the formed ultrafine particles from adhering to the inner surface of the upstream chamber 3, an anti-adhesion treatment may be applied to the inner surface of the upstream chamber 3. In addition, the generated ultrafine particles are
Since the first downstream chamber 4a has a higher degree of vacuum than the upstream chamber 3, the pressure difference between the two causes the carrier gas to flow directly through the contraction/expansion nozzle l and into the first downstream chamber 4a. It turns out.

As shown in FIGS. 1(a) and 1(b), the gas phase excitation device 9 includes a rod-shaped second electrode 9b provided inside a tubular first electrode 9a, and a carrier gas and a raw material in the first electrode 9a. gas 7
is supplied to cause discharge between the electrodes 9a and 9b. Gas phase excitation methods that can be used at this time include:
Examples include a direct current glow discharge method and a high frequency glow discharge method. In addition, the gas phase excitation device 9 is shown in FIG. 3(a), (
As shown in b), the second electrode 9b provided in the first electrode 9a is made into a porous tube, and a carrier gas is supplied into the first electrode 8a, and a raw material gas is supplied into the second electrode 9b. It can also be taken as a thing. With such a configuration, it becomes possible to excite the gas phase while mixing the carrier gas and the source gas more uniformly within the tube.

The contraction/expansion nozzle l opens an inlet port 1a to the upstream chamber 3 at the side end of the first downstream chamber 4a on the upstream chamber 3 side, and the first downstream chamber 4
The outflow port 1b is opened at a, and the upstream chamber 3 is protruded into the upstream chamber 3, and is attached via a common flange. However, the contraction/expansion nozzle 1 may be installed in a state in which it projects into the first downstream chamber 4a. The direction in which the contraction/expansion nozzle 1 should protrude depends on the size of the ultrafine particles Y- to be transferred,
It may be selected depending on the amount, properties, etc.

As mentioned above, the contraction/expansion nozzle l is the inlet 1a.
The opening area is gradually narrowed down to form the throat 2, and the opening area is gradually expanded again to form the outflow port 1b. The nozzle flow rate is determined to be smaller than the exhaust flow rate under the required pressure and temperature of the upstream chamber 3.

As a result, the outlet 1b is properly expanded, and the outlet 1b
This can prevent deceleration, etc. Further, as shown in an enlarged view in FIG. 4(a), it is preferable that the inner circumferential surface near the outlet lb is substantially parallel to the central axis. This is because the flow direction of the ejected carrier gas and a particulates is influenced to some extent by the direction of the inner circumferential surface near the outlet 1b, so that it is possible to make the flow parallel to each other as easily as possible. However, as shown in FIG. 4(b), the angle α of the inner peripheral surface from the throat portion 2 to the outlet 1b with respect to the central axis is
If the angle is 7° or less, preferably 5° or less, peeling phenomenon will not easily occur and the flow of the ejected carrier gas and ultrafine particles will be maintained almost uniformly, so in this case, it is not necessary to form the above-mentioned parallel portion. By omitting the formation of the parallel portion, the contraction/expansion nozzle 1 can be manufactured easily. Also,
If the contraction/expansion nozzle l is made rectangular as shown in Figure 4 (Q), carrier gas and ultrafine particles can be ejected in a slit shape.

Here, the separation phenomenon is a phenomenon in which when there is a protrusion etc. on the inner surface of the contraction/expansion nozzle l, the boundary layer between the inner surface of the contraction/expansion nozzle l and the flowing fluid becomes large and the flow becomes non-uniform. In order to prevent this peeling phenomenon, it is preferable that the above-mentioned angle α, which is more likely to occur as the jet flow becomes faster, is made smaller as the inner surface finishing precision of the contraction-expansion nozzle l becomes lower. The inner surface of the contraction/expansion nozzle 1 conforms to JIS B 08.
01, it is preferable to have three or more inverted triangle marks representing surface finish accuracy, and optimally four or more. In particular,
Since the peeling phenomenon in the enlarged part of the contraction-expansion nozzle 1 greatly affects the subsequent flow of carrier gas and ultrafine particles, the above-mentioned finishing accuracy is determined with emphasis on this enlarged part, so that the production of the contraction-expansion nozzle 1 is improved. It's easy to do. In addition, in order to prevent the occurrence of peeling phenomenon, the throat portion 2 is made a smooth curved surface, and the differential coefficient of the cross-sectional area change rate is
It is necessary to make sure that this does not happen.

The material for the contraction/expansion nozzle l can be widely used, such as iron, stainless steel, and other metals, as well as synthetic resins such as acrylic resin, polyvinyl chloride, polyethylene, polystyrene, and polypropylene, ceramic materials, quartz, and glass. . This material may be selected in consideration of non-reactivity with the generated ultrafine particles, processability, and gas release capacity in a vacuum system. Also, the contraction/expansion nozzle l
The inner surface of the substrate may be plated or coated with a material that is less likely to cause adhesion or reaction of ultrafine particles. Specific examples include polyfluoroethylene coating.

The length of the contraction/expansion nozzle 1 can be arbitrarily determined depending on the size of the device and the like. By the way, contraction/expansion nozzle 1
When flowing through the carrier gas and ultrafine particles, the thermal energy they possess is converted into kinetic energy. Particularly when ejected at supersonic speed, the thermal energy becomes significantly small, resulting in a supercooled state. Therefore, if the carrier gas contains condensed components, it is also possible to actively condense them by the supercooled state, thereby forming ultrafine particles. Since the formation of ultrafine particles by this is homogeneous nucleation, it is easy to obtain homogeneous ultrafine particles. Further, in this case, in order to perform sufficient condensation, it is preferable that the contraction/expansion nozzle l be long. On the other hand, when condensation occurs as described above, thermal energy increases and velocity energy decreases. Therefore, in order to maintain high-speed jetting, it is preferable that the contraction/expansion nozzle l be short.

Pressure ratio P/P of pressure Po in upstream chamber 3 and pressure P in downstream chamber 4
By appropriately adjusting the relationship between o and the ratio A/A of the opening area of the throat portion 2 to the opening area of the outlet 1b, the ultrafine particles are allowed to flow through the contraction/expansion nozzle l. The carrier gas containing .

The sugar mer 7 is arranged in the first downstream chamber 4a so that the second downstream chamber 4b can maintain a higher degree of vacuum above the first downstream chamber 4a.
This is to enable adjustment of the opening area between the first downstream chamber 4b and the second downstream chamber 4b. Specifically, as shown in FIG. 5, two adjustment plates 11.11' each having a dogleg-shaped notch 10, 10' are slid together with their notches 10.10' facing each other. This has been made possible. This adjustment plate II.

11' can be slid from the outside, and the degree of opening is adjusted by the degree of overlap between the two central portions 10 and 10' to allow the passage of the beam and maintain a sufficient degree of vacuum in the second downstream chamber. It is something that Note that the notch 10.1 of the skimmer 7
0' and the adjustment plates 11, 11' may have a semicircular shape or other shapes other than the shape shown in the drawings.

The gate valve 8 has a layered valve body 13 that can be raised and lowered by turning a handle 12, and is open when the beam is traveling. By closing this gate valve 8, the unit in the second downstream chamber 4b can be replaced while maintaining the degree of vacuum in the upstream chamber 3 and the first downstream chamber 4a. Further, in the apparatus of this embodiment, the ultrafine particles are collected in the second downstream chamber 4b, but if the gate valve 8 is a pole valve or the like, especially when the ultrafine particles are metal particles that are easily oxidized, By replacing the unit of the second downstream chamber 4b together with this Pall valve, there is an advantage that the unit can be replaced without the risk of rapid oxidation.

A base body 6 is located in the second downstream chamber 4b for receiving and depositing ultrafine particles transferred as a beam, and collecting the ultrafine particles in a film-formed state. This base body 6 is attached to the second downstream chamber 4b via a common flange, and is attached to the cylinder 1.
4 is attached to a base holder 16 at the tip of a slide shaft 15 that is slid by a slide shaft 15. A shutter 17 is located on the front side of the base 6, so that the beam can be blocked whenever necessary. Further, the substrate holder 16 is configured to heat or cool the substrate 6 under optimal temperature conditions for collecting ultrafine particles.

Incidentally, glass windows 18 are attached to the upper and lower sides of the upstream chamber 3 and the second downstream chamber 4b through common flanges, respectively, as shown in the figure, so that the inside can be observed. Although not shown, the upstream chamber 3 and the first downstream chamber 4a
Similar glass windows (similar to 18 in the figure) are also installed at the front and rear of the second downstream chamber via common flanges. These glass windows 18 can be removed and replaced with various measuring devices, load lock chambers, etc. via a common flange.

Next, the exhaust system in this embodiment will be explained.

The upstream chamber 3 is connected to a main valve 20 via a pressure regulating valve 19.
connected to a. The first downstream chamber 4a is directly connected to a main valve 20a, and this main valve 20a is connected to a vacuum pump 5a. The second downstream chamber 4b is connected to a main valve 20b, which in turn is connected to a vacuum pump 5b. Furthermore, 2
1a and 21b are main valves 20a and 20b, respectively.
The auxiliary valve 23a is connected to the immediate upstream side of the auxiliary valve 22a and 22b.

The vacuum pump 23b is connected to the vacuum pump 5a and is used to check the inside of the upstream chamber 3, the first downstream chamber 4a, and the second downstream chamber 4b. In addition, 24a to 24h are each chamber 3, 4a, 4b and pump 53, 51), 21
a, 21b leak and purge/help.

First, the interference valves 21a and 21b and the pressure regulating valve 1
8, the upstream chamber 3, the first and second downstream chambers 4a, 4
The check in b is performed using the vacuum pumps 20a and 20b.

Next, the auxiliary valves 23a, 23b and the main valves 20a, 2 are closed.
0b is opened and the vacuum pumps 5a and 5b are used to create a sufficient degree of vacuum in the upstream chamber 3 and the first and second downstream chambers 4a and 4b. At this time, by adjusting the opening degree of the pressure regulating valve 19, the degree of vacuum in the first downstream chamber 4a is made higher than that in the upstream chamber 3,
Next, the carrier gas and the raw material gas are flowed, and the skimmer 7 is used to adjust the degree of vacuum in the second downstream chamber 4b to be higher than that in the first downstream chamber 4a. This adjustment can also be performed by adjusting the opening degree of the main valve 20b. Each chamber 3, 4a, 4b is controlled to maintain a constant degree of vacuum throughout the formation of ultrafine particles and the film forming operation by beam injection. This control may be done manually, but each room 3, 4a,
Alternatively, the pressure inside the pump 4b may be detected and the pressure regulating valve 19, main valves 20a, 20b, skimmer 7, etc. may be automatically opened/closed based on the detected pressure. Furthermore, if the carrier gas and fine particles supplied to the upstream chamber 3 are directly transferred to the downstream side via the contraction/expansion nozzle 1, the exhaust gas during transfer will be transferred to the downstream side, that is, the
and only the second downstream chambers 4a and 4b.

The vacuum degree L may be controlled by separately providing the vacuum pumps 5a for the upstream chamber 3 and the first downstream chamber 4a for each chamber 3 and 4a. However, as in this embodiment, , one vacuum pump 5a is used to exhaust the air in the flow direction of the beam, and the upstream chamber 3 is
By controlling the degree of vacuum in the first downstream chamber 4a, it is easy to maintain a constant pressure difference between the two even if there is some pulsation in the vacuum pump 5a. Therefore, there is an advantage that it is easy to maintain a constant flow state that is susceptible to fluctuations in differential pressure.

The suction by the vacuum pumps 5a, 5b is preferably performed from above, particularly in the first and second flow chambers 4a, 4b. By suctioning from the L side, it is possible to prevent the beam from falling due to gravity to some extent.

Although the apparatus according to this embodiment is as described above, the following modifications can be made.

First, the contraction/expansion nozzle l can be tilted vertically and horizontally, and can be scanned at regular intervals, so that film formation can be performed over a wide range. Particularly, this tilting and scanning is advantageous when combined with the rectangular nozzle shown in FIG. 4(C).

The contraction/expansion nozzle l is made of an insulator such as quartz, and microwaves are applied thereto to form active ultrafine particles inside the contraction/expansion nozzle 1, or ultraviolet, infrared, or laser is formed by forming the contraction/expansion nozzle l of a translucent material. It is also possible to irradiate the flow with light having various wavelengths, such as light. It is also possible to provide a plurality of contraction/expansion nozzles 1 to generate a plurality of beams at once. In particular, when a plurality of reduction/enlargement/slip units are provided, by connecting each to an independent upstream chamber 3, beams of different particles can be run simultaneously, allowing stacking or mixed collection of different particles, It is also possible to form new particles by collision of different particles by crossing the beams.

The base body 6 is held movably or rotatably in the vertical and horizontal directions,
It is also possible to receive the beam over a wide range. Further, by winding up the base body 6 into a roll and sending it out one after another so as to receive the beam, a long base body 6 can also be treated with fine particles. Furthermore, the treatment with fine particles may be performed while rotating the drum-shaped base 6.

In this embodiment, the generation chamber 3, the first downstream chamber 4a, and the second downstream chamber 4b are constructed, but the second downstream chamber 4b may be omitted, or a third downstream chamber may be provided on the downstream side of the second downstream chamber of the WIJ.

Fourth...downstream chambers can also be connected. Furthermore, by pressurizing the upstream chamber 3, the first downstream chamber 4a can be made into an open system, and by reducing the pressure in the first downstream chamber 4d, the upstream chamber 3 can be made into an open system. In particular, like an autoclave, the upstream chamber 3 can be pressurized and the first downstream chamber 48 and below can be depressurized.

In this embodiment, active ultrafine particles are formed in the upstream chamber 3, but this is not necessarily necessary, and separately formed particles may be sent to the upstream chamber 3 together with the carrier gas. Further, it is also possible to provide a valve for opening and closing the contraction/expansion nozzle l, and to obtain fine particles by intermittently opening and closing the valve while temporarily storing fine particles in the upstream chamber 3 side. If the valve is opened and closed in synchronization with energy application on the downstream side including the throat section 2 of the contraction/expansion nozzle 1, the burden on the exhaust system can be significantly reduced, and the pulse can be maintained while effectively utilizing the raw material gas. It is possible to obtain a particle flow of . Note that under the same exhaust conditions, the above-mentioned intermittent opening and closing has the advantage that it is easier to maintain a high vacuum on the downstream side. In case of intermittent opening and closing,
A chamber for temporarily storing fine particles may be provided between the upstream chamber 3 and the contraction/expansion nozzle l.

In addition, multiple contraction/expansion nozzles 1 are arranged in series, and the pressure ratio on the upstream side and downstream side is adjusted to maintain the beam speed, and each chamber is made spherical to minimize the generation of dead space. It can also be prevented.

[Effects of the Invention] In the present invention, the carrier gas and the raw material gas are passed between the electrodes configured in a double tube shape having a certain length, so that it is possible to mix the gases uniformly within the tube. I can do it. Furthermore, since the gas passes through the tube, it is possible to discharge the gas without diffusing it to the outside, and it becomes possible to efficiently generate and activate the particles.

[Brief explanation of drawings]

FIG. 1(a) is a perspective view of an apparatus showing an embodiment of the present invention;
(b) is a sectional view taken along the line A-A, FIG. 2 is a schematic diagram showing one embodiment of the present invention applied to a film forming apparatus using ultrafine particles, and FIG. 3(a) is another embodiment of the present invention. A perspective view of the device showing an example, (b) its BB sectional view, FIGS. 4(a) to (C)
5 is a diagram showing an example of the shape of a contraction/expansion nozzle, respectively, and FIG. 5 is an explanatory diagram of a skimmer. 1:lii small expansion nozzle, 1a: inlet, 1b: outlet, 2: throat, 3: upstream chamber, 4: downstream chamber, 4a: first downstream chamber, 4b: second downstream chamber, 5, 5a, 5b: vacuum pump,
6: Base, 7: Skimmer, 8: Gate valve. 9: Gas phase excitation device, 9a: First electrode, 9b: Second electrode, 10.10': Notch, 11, 1
1': Adjustment plate, 12: Handle, 13: Valve body, 14 Niji cylinder, 15 Ni slide shaft, 18: Substrate holder, 17: Shutter, 18 Ni glass window, 19: Pressure adjustment valve, 20a, 20b: Main valve, 21a , 21b: Decompression pump, 22a, 22b: Arabiki valve, 23a, 23b: Auxiliary valve, 24a to 24h: Leak and purge valve. Figure 1(b) q A-A! Ifr plane Fig. 2 Fig. 3 G B-B vr plane Fig. 4 (C)

Claims (1)

[Claims] 1) A gas phase excitation device characterized in that a rod-shaped second electrode is provided at the center of a cylindrical first electrode.