JPH043255B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a particle spraying device used as a means for transporting or spraying particles. It is expected to be applied to formation, doping processing, and new formation sites for fine particles.

In this specification, fine particles refer to atoms, molecules,
Refers to ultrafine particles and general fine particles. Here, ultrafine particles include, for example, in-gas evaporation method, plasma evaporation method, gas phase chemical reaction method using gas phase reaction, colloidal precipitation method using liquid phase reaction, solution spray heat Refers to ultrafine particles (generally 0.5 μm or less) obtained by decomposition methods. General fine particles refer to fine particles obtained by general methods such as mechanical crushing and precipitation treatment. Moreover, a beam refers to a linear flow that flows with a substantially constant trajectory, 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, control of the flow of the particles during the transfer of the particles has been carried out by dividing the entire flow path of the particles flowing together with the carrier gas with a pipe or a housing due to the differential pressure between the upstream and downstream sides. Not too much. 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 housing that defines the flow path for particles.

Furthermore, when spraying fine particles onto a substrate, the fine particles are ejected together with a carrier gas through a nozzle. The nozzle used for spraying the fine particles is a simple parallel pipe 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 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. Therefore, it is impossible to expect such a high transfer speed. Furthermore, it is difficult to avoid contact between the particles and the wall surface of the tube or casing that defines the flow path of the particles throughout 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 for particles is divided by pipe material or a housing, the collection rate of transferred particles will decrease due to the generation of dead spaces in the flow, and the efficiency of using carrier gas for particle transfer will also decrease. .

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

[Means for Solving the Problems] The means taken to solve the above problems will be explained with reference to FIG. 1, which corresponds to an embodiment of the present invention. 1, pressure detecting means 10, 12 for detecting the pressure at the outlet 1c of the contraction/expansion nozzle 1 and the pressure on the downstream side of the contraction/expansion nozzle 1, and pressure detection means 10, 12 for detecting the pressure at the outlet 1c of the contraction/expansion nozzle 1; A particle spraying device equipped with a controller 2 that controls the air supply in the upstream chamber so that the flow of ejected particles becomes a stable beam-like flow, and the above problem can be solved by making the flow of particles into a beam. This is the solution.

The contracting/expanding nozzle 1 in the present invention has an opening area gradually narrowed from an inlet 1a toward an intermediate portion to form a throat portion 1b, and an opening area gradually expanded from this throat portion 1b toward an outlet 1c. This refers to the nozzle that is In FIG. 1, for convenience of explanation,
The inflow side and outflow side of the contraction/expansion nozzle 1 form an upstream chamber 3 and a downstream chamber 4, respectively, which are closed systems. However, in the inflow side and the outflow side of the contraction/expansion nozzle 1 in the present invention, the pressure ratio P ₂ /P ₁ between the upstream pressure P ₁ and the downstream pressure P ₂ cannot be made equal to or lower than the critical pressure ratio. If possible, it may be a closed system or an open system.

[Function] For example, as shown in FIG. 1, when a carrier gas containing dispersed particles is supplied into the upstream chamber 3 and the downstream chamber 4 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 to the downstream chamber 4.
It will flow into.

Here, assuming that the flow passing through the contraction/expansion nozzle expands adiabatically within the contraction/expansion nozzle ₁ , the pressure ratio P ₂ /P 1 of the pressure P ₁ on the upstream side of the contraction/expansion nozzle 1 and the pressure P ₂ on the downstream side is Assuming that the pressure ratio is below the critical pressure ratio,
The speed of the flow ejected from the contraction/expansion nozzle 1 becomes supersonic, and the Matsush number M reached at that speed is determined by the following equation. However, the velocity of the flow is u, the sound velocity at that point is a, and the specific heat ratio of the flow is γ.

Note that the sound speed can be determined by the following equation, where T is the local temperature and R is the gas constant.

a=√ Furthermore, the following relationship exists between the opening area A of the outlet 1c, the opening area A ^* of the throat portion 1b, and the reached Matsuha number M.

Then, if P ₂ /P ₁ is adjusted so that the Matsuha number M determined by this equation (2) from A/A ^* is equal to the Matsuha number M determined by the above equation (1), the ejection from the contraction/expansion nozzle 1 The resulting flow is a properly expanded flow. This proper expansion flow is a flow ejected from the contraction/expansion nozzle 1, and the pressure P _o at the outlet 1c is
is a flow in which the pressure P2 on the downstream side is approximately equal to the pressure _P2 .
Also, for the proper expansion flow where P _o = P ₂ , P _o
A flow where <P ₂ is called an underexpansion flow, and a flow where P _o >P ₂ is called an overexpansion flow.

When the flow ejected from the contraction-expansion nozzle 1 becomes a proper expansion flow of supersonic speed, the flow becomes a flow having a substantially uniform velocity distribution in the cross-sectional direction along the inner wall surface direction of the outlet 1c of the contraction-expansion nozzle 1, Beamed. Therefore, the particles transported as a beam-formed flow are transported 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 supersonic speed. will be done.

For this reason, if the active particles are directly transferred as a beam, they can be transferred as spatially independent beams using ultrasonic waves. can be collected. Therefore, it becomes possible to collect fine particles in a good active state. Also,
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 spray area can be easily controlled.

Incidentally, the above equations (1) and (2) hold true when the flow undergoes adiabatic expansion within the contraction/expansion nozzle 1, but do not hold when the flow generates heat or absorbs heat within the contraction/expansion nozzle 1. Therefore, simply A/A ^*
In some cases, it may be difficult to reliably obtain an appropriate expansion flow only by adjusting P ₂ /P ₁ according to. Therefore, in the present invention,
Pressure P _o at the outlet 1c of the contraction/expansion nozzle 1
and the pressure P ₂ on the downstream side of the contraction/expansion nozzle 1
The air supply on the upstream side is controlled so that they are almost equal. In other words, when P _o > P ₂ , the upstream air supply is promoted to increase P ₂ , and the pressure is adjusted so that P _o = P ₂ , and when P _o < P ₂ , the upstream air supply is increased. The pressure is adjusted so that P ₂ is lowered by suppressing energy so that P _o = P ₂ .

The above control is performed by the controller 2,
This ensures the formation and maintenance of an appropriate expansion flow despite the heat absorption and heat absorption of the flow within the contraction/expansion nozzle 1 and slight fluctuations in the upstream pressure _P1 . Therefore, the beam formation of the above-mentioned flow can be constantly obtained.

[Example] As shown in FIG. 1, an upstream chamber 3 and a downstream chamber 4 are connected via a contraction/expansion nozzle 1.

A supply valve 7 is connected to the upstream chamber 3 for supplying a carrier gas containing fine particles dispersed therein. Further, the pressure P ₁ in the upstream chamber 3 is detected by a pressure gauge 8 . This pressure gauge 8 is for checking the pressure P ₁ in the upstream chamber 3.

As shown in FIG. 2, the contraction _/ expansion nozzle 1 has a static pressure hole 9 formed in the vicinity of its outlet 1c. It is now possible to detect a total of 10. It is preferable that the static pressure hole 9 has a diameter as small as possible without causing any burrs or the like to protrude from the inner surface so as not to disturb the flow inside the contraction/expansion nozzle 1. Further, the static pressure hole 9 is preferably formed sufficiently close to the outlet 1c so that the pressure at the outlet 1c can be detected as accurately as possible.

As shown in FIGS. 3a and 3b, the static pressure hole 9 is
Although the opening may be made on the inner surface inclined with respect to the central axis, it is preferable that the opening be made on a plane parallel to the central axis, as shown in FIG. This is because it is difficult to disturb the flow inside the contraction/expansion nozzle 1. From this point of view, it is preferable for the contraction/expansion nozzle 1 to have a rectangular cross section as shown in FIG. 2 rather than a circular cross section for the contraction/expansion nozzle 1 because it is easier to leave an inner surface parallel to the central axis.

As described above, the contraction/expansion nozzle 1 has an opening area gradually narrowed from the inlet 1a to the throat portion 1.
b, and the opening area gradually expands again to form the outflow port 1c.
As shown in the enlarged view, it is preferable that the inner circumferential surface near the outlet 1c is substantially parallel to the central axis. This is to facilitate parallel flow as much as possible since the flow direction of the ejected carrier gas and fine particles is influenced to some extent by the direction of the inner circumferential surface near the outlet 1c. However, as shown in FIG. 3b, the angle α of the inner circumferential surface extending from the throat portion 1b to the outlet 1c with respect to the central axis is
If the angle is set to 7° or less, preferably 5° or less, peeling phenomenon is less likely to occur and the flow of the ejected carrier gas and fine particles is 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.

Here, the above-mentioned separation phenomenon means that when there is a protrusion 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 is 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 peeling phenomenon, the above-mentioned angle α is preferably made smaller as the inner surface finish accuracy of the contraction/expansion nozzle 1 is inferior. The inner surface of the contraction/expansion nozzle 1 has three or more, preferably four or more, inverted triangular marks indicating surface finish accuracy as defined in JIS B 0601.
In particular, the peeling phenomenon in the enlarged part of the converging/expanding nozzle 1 greatly affects the subsequent flow of carrier gas and particles, so by determining the finishing accuracy with emphasis on this enlarged part, the Easy to manufacture. Furthermore, in order to prevent the occurrence of a peeling phenomenon, the throat portion 1b needs to have a smooth curved surface so that the differential coefficient in the rate of change in cross-sectional area does not become ∞.

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, when the carrier gas and the particles flow through the contraction/expansion nozzle 1, the thermal energy they possess is converted into kinetic energy. In particular, since it is ejected at supersonic speed, the thermal energy is significantly reduced and a supercooled state can be created. If the carrier gas contains condensed components, it is also possible to actively condense them by the supercooled state and thereby form fine particles. By forming fine particles in this way, homogeneous fine particles can also be obtained. Further, in this case, in order to perform sufficient condensation, it is preferable that the contraction/expansion nozzle 1 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 1 be short.

A pump 5 is connected to the downstream chamber 4 via an exhaust valve 11 in order to discharge the inflowing carrier gas out of the system. The pressure P ₂ in the downstream chamber 4 is
It is detected by the pressure gauge 12, and its signal is sent to the controller 2 together with the signal of the pressure P _o at the outlet 1c detected by the pressure gauge 10 described above. The controller 2 opens and closes the exhaust valve 11 based on the received P _o and P ₂ signals and the pressure P _put in the downstream chamber 4 set in advance in the controller 2 to keep the pressure in the downstream chamber 4 constant. At the same time, the supply valve 7 is opened and closed to control the supply of air to the upstream chamber 3, that is, the supply of carrier gas accompanied by fine particles. Further, in the downstream chamber 4, a base body 6 is provided for collecting fine particles transferred as a beam-formed flow by the contraction/expansion nozzle 1.

Next, the operating state of this device will be explained.

First, the controller 2 is instructed to set the desired set pressure of the downstream chamber 4.
Set P _put , open exhaust valve 11, and pump 5.
While operating the supply valve 7, the fine particles are supplied to the upstream chamber 3 together with the carrier gas. At this time, the pressure P ₁ in the upstream chamber 3 can be confirmed with the pressure gauge 8.

On the other hand, the fine particles supplied into the upstream chamber 3 flow into the downstream chamber 4 through the contraction/expansion nozzle 1 together with the carrier gas. In particular, when the pressure P ₂ in the downstream chamber 4 is sufficiently lower than the pressure P ₁ in the upstream chamber 3, and P ₂ /P ₁ becomes less than the critical pressure ratio, the fine particles and the carrier gas move at supersonic speed through the contracting and expanding nozzle. 1 to the downstream chamber 4.

Pressure at the outlet 1c of the contraction/expansion nozzle 1
P _o is detected by the pressure gauge 10 and the pressure inside the downstream chamber 4
P ₂ is detected by a pressure gauge 12 and a signal is sent to the controller 2, respectively. As shown in FIG. 4, the controller 2 compares P ₂ and P _o and operates the supply valve 11 in the closing direction when _{P o} > P _{2 and} vice versa.
At this time, the supply valve 11 is operated in the opening direction.
Therefore, when P ₂ is too low, the inflow of particles and carrier gas from the contraction/expansion nozzle 1 increases, causing P ₂ to rise, and conversely, when P ₂ is too high,
The inflow amount of particles and carrier gas from the contraction/expansion nozzle 1 decreases, and P ₂ decreases, and is maintained at approximately P _o =P ₂ . As a result, the flow of fine particles and carrier gas ejected from the contraction/expansion nozzle 1 becomes a properly expanded flow and is converted into a beam. The particles transported as a beam-formed flow are basically 6
The carrier gas collides with and is collected, and the carrier gas is sequentially discharged to the outside of the system via the exhaust valve 11.

Although it is possible to form a flow into a beam with only the above operation, it is preferable to maintain the pressure P ₂ in the downstream chamber 4 constant in order to obtain a more stable beam formation. That is, as shown in FIG. 4, the preset pressure P _put of the downstream chamber 4 and the actual pressure P ₂ are compared, and when P _put > P ₂ , the exhaust valve 1 is
1 in the closing direction, and when P _put <P ₂ , the exhaust valve 11 is operated in the opening direction. When this operation occurs, P ₂ changes, so the adjustment of P _o = P ₂ made in the previous stage becomes deviated, so the adjustment is made again to make P _o = P ₂ , and gradually P _o = P ₂ and Converge to P _put = P ₂ .

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

First, the contraction/expansion nozzle 1 can be tilted vertically and horizontally, and can be scanned at regular intervals. In this way, for example, when forming a film by spraying fine particles onto the substrate 6, it is possible to form a film over a wide range. Particularly advantageous is the combination with the rectangular nozzle of FIG.

The contraction/expansion nozzle 1 is made of a transparent material to emit ultraviolet light,
The flow may be irradiated with light having various wavelengths such as infrared light and laser light. In this way, by irradiating light, it is possible to activate fine particles within the contraction/expansion nozzle 1, or to supply raw material gas and carrier gas to the upstream chamber 3 to generate fine particles within the contraction/expansion nozzle 1. Become.

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 contraction/expansion nozzles 1 are provided, by connecting each to an independent upstream chamber 3, beams of different particles can be run simultaneously.
It is also possible to form new particles by stacking or collecting different particles together, or by colliding different particles with each other by crossing beams.

The base body 6 can also be held movably or rotatably in the vertical and horizontal directions so that it can receive the beam over a wide range. Further, by winding up the base body 6 into a roll and receiving the beam while sequentially feeding the base body 6, 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.

[Effects of the Invention] According to the present invention, fine particles can be transported at supersonic speed in a spatially independent state. 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 fine 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 particle spraying 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. 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 imparted. In addition, by providing a place for energy exchange that is different from the conventional one,
It is also possible to easily create intermolecular compounds formed by relatively weak intermolecular forces such as hydrogen bonds and Van der Waals bonds.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing one embodiment of the present invention, and FIG.
The figure is a partially cutaway perspective view showing an example of a contraction/expansion nozzle, FIGS. 3a and 3b are longitudinal sectional views showing other examples of the contraction/expansion nozzle, and FIG. 4 is a flowchart of the controller. 1: contraction/expansion nozzle, 1a: inlet, 1b: outlet, 1c: throat, 2: controller, 3: upstream chamber,
4: downstream chamber, 5: pump, 6: base, 7: supply valve, 8, 10, 12: pressure gauge, 9: static pressure hole, 1
1: Exhaust valve.

Claims (1)

[Claims] 1. A particle spraying device comprising an upstream chamber and a downstream chamber connected via a contraction/expansion nozzle, and sprays particles that have passed through the contraction/expansion nozzle onto a base provided in the downstream chamber, wherein the contraction/expansion nozzle pressure detecting means for detecting the pressure at the outlet and the pressure downstream of the contraction/expansion nozzle, and based on the detected pressure, the flow of particles ejected from the contraction/expansion nozzle becomes a stable beam-shaped flow. A particulate spraying device characterized in that it is equipped with a controller for controlling air supply in an upstream chamber.