JPS61218810A - Minute particle flow control apparatus - Google Patents

Abstract

PURPOSE:To supersonically transport minute particles in a spatially independent state by providing a passage with a shrinkage/expansion nozzle, homogenizing minute particle flow, and making the flow come into a beam. CONSTITUTION:A passage is provided with a shrinkage/expansion nozzle 1 in which a passage is gradually shrinked from an inlet 1a toward a throat 2 and gradually expanded therefrom toward an outlet 1b. A carrier gas in which minute particles are suspended and dispersed is supplied to an upstream chamber 3 and a downstream situated chamber 4 is exhausted by a vacuum pump 5. This construction enables the minute particles to come into a beam and a supersonic transport of the minute particles under a spatially independent state without an interference with the inner wall surface of the downstream situated chamber 4.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a flow control device for a particulate flow that is used as a means for transporting or spraying particulates. It is expected to be applied to the formation of composite materials, doping processing, and new formation sites for fine particles.

In this specification, 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,
General fine particles, which refer to ultrafine particles (generally 0.5 gm or less), refer to fine particles obtained by general methods such as mechanical pulverization and precipitation treatment. In addition, a beam refers to a jet having a substantially constant cross-sectional area in the flow direction, and its cross-sectional shape is not limited.

[Prior Art] Generally, fine particles are dispersed and suspended in a carrier gas and transported by the flow of the carrier gas.

Conventionally, the control of the flow of fine particles accompanying the transfer of fine particles has been carried out simply by dividing the entire flow path of the fine particles flowing together with the carrier gas with a pipe material or a casing based on the differential pressure between the upstream side and the downstream side. do not have. Therefore, although the flow of particles varies in strength and weakness, the flow of particles inevitably occurs in a dispersed state throughout the pipe material or casing that defines the flow path for particles.

Furthermore, when spraying fine particles onto a substrate, the fine particles are jetted out together with a carrier gas through a nozzle. The nozzle used to spray the fine particles is a simple parallel tube or a tapered nozzle, and the jet cross section of the fine particles immediately after being ejected is certainly narrowed down according to the area of the nozzle end face. However, since the jet is diffused at the exit surface of the nozzle, the flow path is merely temporarily constricted, and the speed of the jet does not exceed the speed of sound.

[Problems to be Solved by the Invention] By the way, it is not possible to divide the entire flow path of fine particles with a pipe material or a casing, and to transport the fine particles together with a carrier gas along this flow path using a differential pressure between the upstream side and the downstream side. However, it is not possible to expect such a high transfer speed, and it is difficult to avoid contact between the particles and the wall surface of the tube or casing that defines the wave path of the particles over the entire transfer section.

For this reason, there is a problem in that when moving particularly active fine particles to their collection position, the activity tends to disappear over time or due to contact with the tube material or the wall surface of the casing.

In addition, if the entire flow path of particles is divided by pipe material or housing,
Due to the generation of dead space in the flow, the collection rate of the transported particles decreases, and the efficiency of using the carrier gas for transporting the particles also decreases.

On the other hand, in conventional parallel tubes and tapered nozzles, the density distribution of fine particles in the jet stream that has passed through the jet stream becomes a diffusion flow. Therefore, when spraying fine particles onto a substrate, it is difficult to control uniform spraying. Furthermore, uniform spraying makes it difficult to control the area.

[Means for Solving the Problems] One of the measures taken to solve the above problems is explained with reference to FIG. 1, which is an explanatory diagram of the basic principle of the present invention. With a flow control device for particulate flow,
The above problems are solved by making the flow of particles uniform and making it possible to form a beam.

The contraction/expansion nozzle 1 in the present invention is a throat portion 2 in which the opening area is gradually narrowed from the inlet 1a toward the middle portion, and the opening area is gradually expanded from the throat portion 2 toward the outlet 1b. In Figure 1, the nozzle is
For convenience of explanation, the inflow side and outflow side of the contraction/expansion nozzle l are as follows:
It is connected to an upstream chamber 3 and a downstream chamber 4, each of which is a closed system. However, in the present invention, the inflow and outflow sides of the contraction/expansion nozzle 1 can be either a closed system or an open system, as long as a pressure difference can be created between the two and the particles can flow together with the carrier gas. Good too.

[Function] For example, as shown in FIG.
When the inside is evacuated by the vacuum pump 5, a pressure difference is created between the upstream chamber 3 and the downstream chamber 4. Therefore, the supplied carrier gas containing fine particles flows from the upstream chamber 3 through the contraction/expansion nozzle 1 and flows into the downstream chamber 4 .

By the way, the contraction/expansion nozzle 1 not only ejects fine particles ′ together with the carrier gas according to the pressure difference between the upstream side and the downstream side, but also serves to equalize the flow of the ejected carrier gas and fine particles. . Therefore, if the fine particles are sprayed onto the base 6 using this uniform flow of the fine particles, the fine particles can be uniformly sprayed onto the base 6.

In addition, the contraction/expansion nozzle 1 adjusts the pressure ratio in the upstream chamber 3 and the downstream chamber 4 and the ratio A/a between the opening area a of the throat part 2 and the opening area A of the outflow port lb. The flow of particles ejected together with gas can be sped up. If the pressure ratio in the upstream chamber 3 and the downstream chamber 4 is less than the critical pressure ratio, the flow velocity at the outlet of the contraction/expansion nozzle l becomes a subsonic flow or less, and the particles are decelerated and ejected together with the carrier gas.

Further, if the distribution pressure ratio E is equal to or higher than the critical pressure ratio, the exit flow velocity of the contraction/expansion nozzle l becomes a supersonic flow, and the fine particles can be ejected together with the carrier gas at an ultrahigh speed.

In the above-mentioned ejection where the pressure ratio is less than the critical pressure ratio, the ejected carrier gas and fine particles form a uniform diffusion flow, making it possible to uniformly spray the fine particles over a relatively wide range at once.

On the other hand, when particles are ejected in a fixed direction along with carrier gas as an ultra-high-speed flow as described above, the carrier gas and particles travel straight while maintaining almost the jet cross section immediately after ejection.
Beamed. Therefore, the flow of particles carried by this carrier gas is also converted into a beam, which moves through the space within the downstream chamber 4 with minimal diffusion, in a spatially independent state without interference with the wall surface of the downstream chamber 4, and at an ultra-high speed. It will be transported by

For this reason, it is possible, for example, to form active particles in the upstream chamber 3 and transfer them directly into a beam through the contraction/expansion nozzle 1, or to activate them within the contraction/expansion nozzle 1 or immediately after the contraction/expansion nozzle 1. By forming fine particles having a particle size and transferring them as a beam, it is possible to transfer them as a spatially independent beam at supersonic speed.
For example, it can be deposited and collected on a substrate 6 provided in the downstream chamber 4. Therefore, it becomes possible to collect fine particles in a good active state. Further, since the fine particles are sprayed onto the substrate 6 as a beam whose jet cross section is substantially constant in the flow direction, the area of this spraying can be easily controlled.

[Example] Fig. 2 is a schematic diagram of an example in which the present invention is utilized for film formation using ultrafine particles.
is an upstream chamber, 4a is a first downstream chamber, and 4b is a second downstream chamber.

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 wave R9 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 the contraction/expansion nozzle 1 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 I and into the first downstream chamber 4a. It turns out.

As shown in FIG. 3(a), the gas phase excitation device 9 includes a rod-shaped first electrode 8a disposed within a tubular second electrode eb, and a carrier gas and source gas supplied into the second electrode 9b. Thus, a discharge is caused between both electrodes 9a and 9b. Further, the gas phase excitation device 9, as shown in FIG. 3(b),
The first electrode 9a provided in the second electrode 9b may be a porous tube to supply carrier gas and raw material gas between the two electrodes 9a and 9b through the inside of the first electrode sa. As shown, both half-tubular electrodes 9a, 9
b are joined in a tubular shape via an insulating material 9C, and both electrodes 9a,
It is also possible to supply the carrier gas and source gas into the tube formed by 9b.

The contraction/expansion nozzle 1 has an inlet 1a opened in 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 4d. The direction in which the contraction/expansion nozzle 1 should be projected may be selected depending on the size, amount, properties, etc. of the ultrafine particles to be transferred.

As mentioned above, the contraction/expansion nozzle l is the inlet 1a.
It is sufficient if the opening area is gradually narrowed down to form the throat part 2, and then the opening area is gradually expanded again to form the outflow port 1b, which is shown enlarged in Fig. 4(a). As such, it is preferable that the inner circumferential surface near the outlet lb is approximately parallel to the central axis. This means that the flow direction of the jetted carrier gas and ultrafine particles is to some extent This is to make it as easy as possible to create a flat folded flow, since the direction of the surface will affect the flow. However, as shown in FIG. 4(b), if the angle α of the inner peripheral surface from the throat portion 2 to the outlet 1b with respect to the central axis is set to 7° or less, preferably 5° or less, a peeling phenomenon occurs. In this case, it is not necessary to form the above-mentioned parallel portion, since the flow of the ejected carrier gas and ultrafine particles is maintained substantially uniformly. By omitting the formation of the parallel portion, the contraction/expansion nozzle 1 can be manufactured easily. Furthermore, if the contraction/expansion nozzle l is made rectangular as shown in FIG. 4(C), carrier gas and ultrafine particles can be ejected in a slit shape.

Here, the above-mentioned separation phenomenon means that when there is a protrusion or the like on the inner surface of the contraction/expansion nozzle 1, the boundary layer between the inner surface of the contraction/expansion nozzle 1 and the flowing fluid becomes large.

This refers to a phenomenon in which the flow becomes non-uniform, and the higher the speed of the jet flow, the more likely it is to occur.In order to prevent this separation phenomenon, it is preferable that the above-mentioned angle α be made smaller as the inner surface finishing precision of the contraction-expansion nozzle 1 is inferior. . The inner surface of the contraction/expansion nozzle l has three or more inverted triangular marks representing surface finishing accuracy as defined in JIS 80801, and four or more is preferred. 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, by determining the finishing accuracy with emphasis on this enlarged part, it is possible to Easy to manufacture. Further, in order to prevent the occurrence of a peeling phenomenon, the throat portion 2 needs to have a smooth curved surface so that the differential coefficient in the rate of change in cross-sectional area does not become (1).

The material of the contraction/expansion nozzle l is, for example, iron.

In addition to stainless steel and other metals, acrylic resin,
A wide variety of materials can be used, including synthetic resins such as polyvinyl chloride, polystyrene, polystyrene, and polypropylene, ceramic materials, quartz, and glass. This material may be selected in consideration of non-reactivity with the generated ultrafine particles, processability, gas release properties in a vacuum system, etc. Furthermore, the inner surface of the contraction/expansion nozzle 1 can 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 l can be arbitrarily determined depending on the size of the apparatus and the like. By the way, the contraction/expansion nozzle l
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, and the pressure ratio in the upstream chamber 3 and the downstream chamber 4, and the opening area a of the throat part 2 and the opening area of the outflow port 1b. By appropriately adjusting the relationship with the ratio A/a and causing it to flow through the contraction/expansion nozzle 1, the carrier gas containing ultrafine particles is converted into a beam and flows from the first downstream chamber 4a to the second downstream chamber 4b. It will flow at super high speed.

The skimmer 7 is installed in the first downstream chamber 4a so that the second downstream chamber 4b can maintain a sufficiently higher degree of vacuum than 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 dogleg-shaped notches 10 and 10' can be slid past each other with their notches 10.10' facing each other. It has been established in This adjusting plate 11° 11'' can be slid from the outside, and depending on the overlap between the two central portions 10 and 10', it can allow the beam to pass through and maintain a sufficient degree of vacuum in the second downstream chamber. The opening degree is adjusted.The shape of the notch 10.10' of the skimmer 7 and the adjustment plate 11.11' may be semicircular or other shapes other than the shape shown in the figure.

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. In addition, in the apparatus of this embodiment, 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 18 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. Also, although not shown, the north flow chamber 3, 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 the main valve 20b.

Furthermore, this main valve 20b is connected to a vacuum pump 5b. In addition, 21a and 21b are connected to the valve 22 immediately upstream of the main valves 20a and 20b, respectively.
a, 22b, and an auxiliary valve 23a.

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-24h are each chamber 3, 4a, 4b and pump 5a, 5b, 21
a, 21b are leak and purge valves.

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
0 The irregularities in b are 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 upstream chamber 3. A sufficient degree of vacuum is created in 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. The chambers 3, 4a, and 4b are 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.

The degree of vacuum may be controlled by separately providing the vacuum pumps 5a for the upstream chamber 3 and the first downstream chamber 4d for each chamber 3.4a, but as in this embodiment, One vacuum pump 5a evacuates in the flow direction of the beam, and the upstream chamber 3
By controlling the degree of vacuum of the first downstream chamber 4a and 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. It has the advantage of being easy to maintain a constant flow state.

The suction by the vacuum pumps 5a, 5b is preferably performed from the E side, especially in the first and second downstream chambers 4a, 4b. By suctioning from the L side, the descent of the beam due to gravity can be suppressed to some extent. be able to.

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 up and down and left and right, and can be scanned at regular intervals.

It is also possible to form a film 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 formed of an insulator such as quartz.

Microwaves are applied there to form active ultrafine particles in a contraction/expansion nozzle l, or a transparent material is used to irradiate the flow with light having various wavelengths such as ultraviolet, infrared, and laser light. You can also do that. It is also possible to provide a plurality of contraction/expansion nozzles l to generate a plurality of beams at once. In particular, when a plurality of contraction/expansion nozzles 1 are provided, by connecting each to an independent upstream chamber 3, beams of different particles can be run at the same time, allowing stacking or mixed collection of different particles, and beam It is also possible to form new particles by collision of different particles by crossing them.

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 downstream of the second downstream chamber.

Fourth...downstream chambers can also be connected. Further, 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 4a, 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. It is also possible to obtain fine particles by providing a valve for opening and closing 1 and 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 part 2 of the contraction/expansion nozzle l, the load 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 l are arranged in series, and the pressure ratio on the upstream and downstream sides is adjusted to maintain the beam speed, and each chamber is made spherical to minimize dead space. It can also be prevented.

[Effects of the Invention] According to the present invention, fine particles can be transported as a uniformly dispersed supersonic beam.

Microparticles can be transported spatially independently and at ultrahigh speeds. Therefore, the active particles can be reliably transported as they are to the collection position, and by controlling the beam irradiation surface, the spraying area can be accurately controlled.

In addition, it becomes a focused ultra-high-speed parallel flow called a beam, and when it is made into a beam, thermal energy is converted to kinetic energy, and the particles in the beam become frozen, so we can create a new reaction field that utilizes these. I have high hopes for what I will achieve. Furthermore, according to the flow control device of the present invention, since the fluid is in the frozen state, it is also possible to define the microscopic state of molecules in the fluid and handle the transition from one state to another state. In other words, it is possible to perform chemical reactions in the gas phase using a new method in which various energy levels of molecules are defined and energy corresponding to the levels is added. Also.

By providing a field for energy exchange that is different from the conventional one, it is also possible to easily create intermolecular compounds formed between relatively weak molecules such as hydrogen bonds and van der Waals bonds.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of the basic principle of the present invention, Figure 2 is a schematic diagram showing an embodiment of the present invention applied to a film forming apparatus using ultrafine particles, and Figures 3 (a) to (C) are Each figure shows an example of a gas phase excitation device, FIGS. 4(a) to 4(C) each show an example of the shape of a contraction/expansion nozzle, and FIG. 5 is an explanatory diagram of a skimmer. 1: contraction/expansion nozzle, 1a: inlet. lb2 outlet, 22 throat, 3: upstream chamber. 4: downstream chamber, 4a: first downstream chamber, 4b: second downstream chamber, 5, 5a, 5b: vacuum pump. 6: Substrate, 7: Skimmer, 8: Gate valve, 9: Gas phase excitation device, 9a: First electrode, 9b: Second electrode, to, 10': Notch. 11, 11": Adjustment plate, 12: Handle, 13: Valve body, 14 Niji cylinder, 15 Ni slide shaft, 16: Base 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.

Claims (1)

[Claims] 1) A flow control device for a particle flow, characterized in that a contraction/expansion nozzle is provided in a flow path.