JPS62131510A - Fine particle spraying device - Google Patents

Abstract

PURPOSE:To enable the titled spraying device to perform a uniform spray of fine particles in a highly efficient manner by a method wherein a plurality of upstream chambers, which jet out fine particles through a reduction-expansion nozzle, are provided in such a manner that the nozzle is directed to a movable substrate and that the adjoining upstream chambers are shifted in front and rear and left and right directions to be directed toward the moving direction of the substrate. CONSTITUTION:A plurality of upstream chambers 2, with which fine particles are jetted out through a reduction-expansion nozzle 1 which is directed to a movable substrate in such a manner that the adjoining upstream chambers 2 are shifted in front and rear and left and right directions to be directed toward the moving direction of the substrate 3. A throat part 1b is formed on the reduction-expansion nozzle 1 by gradually narrowing its opened area from an inflow hole 1a toward the intermediate part, and the opened area is gradually made wider from the throat part 1b toward the outflow hole 1c. When fine particles are jetted out in the fixed direction, the stream of the fine particles makes a straight advance almost maintaining the cross section of the jet stream formed immediately after jetting, the fine particle stream is brought into a beam form, and it is conveyed at a supersonic speed in the space located on the downstream side by the minimum diffusion in the state wherein it has no interference with the wall surface on the downstream side and that it is spatially independent.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a particle spraying device used for spraying particles onto a substrate. It is expected to be applied to dope processing or 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,
A gas phase chemical reaction method and a liquid phase reaction were used. obtained by colloidal precipitation method, solution spray pyrolysis method, etc.
Refers to ultrafine particles (generally 0.5 l or less). General fine particles 1 refers to general particles produced by mechanical pulverization, precipitation treatment, etc.
Refers to fine particles obtained by this method. 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] Conventionally, when spraying fine particles onto a substrate, the fine particles are ejected through a nozzle. However, the nozzle used to blow the particles is just a wide parallel tube or a tapered nozzle.

[Problems to be Solved by the Invention] By the way, with a simple parallel tube or tapered nozzle, the ejected flow of fine particles does not exceed the speed of sound and is diffused at the exit surface of the nozzle, so it is only temporary. It is only a method that narrows down the flow path, and cannot prevent fine particles from dispersing unevenly over a wide area.Therefore, multiple nozzles are installed toward a substrate with a large area. Even if you try to spray all at once, it is difficult to spray uniformly.

[Means for Solving the Problems] The means taken to solve the above problems will be explained with reference to FIGS. 1 to 3, which correspond to an embodiment of the present invention. A plurality of L flow chambers 2 for ejecting fine particles are provided with the nozzles 1 directed toward a movable base 3, and adjacent upstream chambers 2 are shifted from front to back and left and right in the direction of movement of the base 3. The above-mentioned problems have been solved by using a spraying device of this type.

An uninvented contraction/expansion nozzle l is a throat portion 1b whose opening area is gradually narrowed from an inlet la toward an intermediate portion, and whose opening area is gradually expanded from this throat portion 1b toward an outlet 1c. This refers to the nozzle that is

[Function] The contraction/expansion nozzle 1 has a pressure ratio P/P between a pressure Po on its upstream side and a pressure P on its downstream side, an open area ◆ of the throat portion 1b, and an open area A of the outlet 1c. The ratio A/A” and J
! lf! i′i, the flow of ejected fine particles can be sped up. And the pressure ratio P between the upstream side and the downstream side
/PO is larger than the critical pressure ratio, the contraction-expansion nozzle 1
The outlet flow velocity becomes subsonic or less, and the particles are decelerated and ejected. Further, if the pressure ratio is equal to or lower 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 at a supersonic velocity.

Here, the velocity of the particle flow is U, and the sound velocity at that point is a.
, the specific heat ratio of the particle flow is γ, and assuming that the particle flow is a compressible one-dimensional flow and expands adiabatically, the Matsuha number M reached by the particle flow is given by the following equation from the upstream pressure Po and the downstream pressure P. It is determined by the formula, especially when P/P is less than the critical pressure ratio, M
is 1 or more.

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

a = "7" Also, the following relationship exists between the opening area A of the outflow port 1c, the opening area A of the throat portion 1b, and the Matsuha number M.

Therefore, the pressure ratio P between the upstream pressure Po and the downstream pressure P
/P, the opening area ratio A/A'' can be determined according to the Matsuha number M determined from equation (1), and A/A'' can be used to determine (2
) By adjusting P/Pa t- according to M determined from the equation, it is possible to eject the particulate flow ejected from the expansion/contraction nozzle l as an appropriately expanded flow.

The velocity U of the particle flow at this time can be determined by the following equation (3).

u = M la] 〒(+ + 1,000 M 2 T +e+ (
3) When particles are ejected in a fixed direction as a properly expanded flow at supersonic speed as described above, the particle flow travels straight while maintaining almost the jet cross section immediately after ejection, and becomes a beam. Therefore, this flow of particles is also converted into a beam and is transported at supersonic speed through the space on the downstream side with minimal diffusion, in a spatially independent state without interference with the wall surface on the downstream side.

In this way, the fine particles are transferred in the form of a beam, and dispersion during transfer is minimized, so that the fine particles can be uniformly sprayed onto the substrate 3.

On the other hand, if a large number of upstream chambers 2 are arranged on the left and right with respect to the moving direction of the base body 3, spraying over a large area becomes possible. but,
Since it is difficult to extremely downsize the upstream chamber 2, there is a limit to the number of chambers that can be arranged in the left-right direction.

Therefore, in the present invention, the adjacent upstream chambers 2 are shifted from front to back and left and right in the direction of movement of the base 3, so that a large number of upstream chambers 2 can be installed, even if the spraying area is limited and beam-shaped. By assembling a large number of them, it is possible to spray a large area as a whole.

[Example] Fig. 1 is a schematic diagram of an embodiment in which the present invention is applied to a film forming apparatus using ultrafine particles, and Fig. 2 is an enlarged sectional view of the upstream chamber 2. 1 in Fig. 0 is a reduced scale. Expanding nozzle, 2 is upstream chamber,
3 is a base body, and 4 is a downstream chamber.

The downstream chamber 4 has a cylindrical shape, and three upstream chambers 2 having contraction/expansion nozzles 1 are connected around the downstream chamber 4 .

Each contraction/expansion nozzle l is directed toward the base body 3 in the downstream chamber 4, and communicates the upstream chamber 2 with the downstream chamber 4.

The base body 3 in the downstream chamber 4 has a cylindrical drum shape and is rotatably provided. The upstream chamber 2 is provided in a spiral position around the downstream chamber 4, as shown by the dashed line in the figure, and the adjacent upstream chambers 2 are arranged in the front, back, left, and right directions in the direction of rotation of the base body 3. are located out of alignment.

The inside of the downstream chamber 4 is evacuated by a pump 5, which makes it possible to adjust the pressure on the upstream and downstream sides of the contraction/expansion nozzle l, and also directly removes excess gas and reaction products inside the downstream chamber 4. It can be discharged out of the system.

In the upstream chamber 2, a cavity resonator 7 is provided which has an opening 6 at a position opposite to the contraction/expansion nozzle l. A microwave introduction window 8 made of a material that transmits microwaves, such as a quartz plate, is provided on the rear surface of the cavity resonator 7, and microwaves are introduced from a waveguide 9 connected thereto. It is now possible to do so. Further, a non-film forming gas is supplied from the rear surface of the cavity resonator 7 via a supply valve 10a.

When microwaves are introduced while a non-film forming gas is supplied, plasma is generated within the cavity resonator 7. This plasma is drawn out from the opening 6 toward the contraction/expansion nozzle 1 by the magnet 11 . The cavity resonator 7 preferably satisfies electron cyclotron resonance (EC:R) conditions so that plasma can be generated efficiently, and the magnet 11 is omitted to simplify the device. It is also possible.

On the other hand, a supply valve 10b is provided immediately before the contraction/expansion nozzle l.
An annular supply pipe 12 connected to the supply pipe 12 is provided, and a film forming gas is supplied through a small hole provided in the supply pipe 12 and brought into contact with the plasma. On the other hand, since the inside of the downstream chamber 4 is evacuated by the pump 5, the film forming gas activated by contact with the plasma is directly ejected from the contraction/expansion nozzle l to the downstream chamber 4.

Here, the non-film forming gas is, for example, N2. N2゜Ar
A film-forming gas refers to a gas that does not produce a film-forming ability by itself, such as , Me, etc., and a film-forming gas refers to a gas that produces a film-forming ability when activated, such as disilane gas.

The contraction/expansion nozzle 1 has its inlet port 1a opened to the upstream chamber 2, and its outflow IC opened to the downstream chamber 4, thereby communicating the upstream chamber 2 and the downstream chamber 4.

As mentioned above, the contraction/expansion nozzle 1 has an inlet port 1a.
The opening area is gradually narrowed down to form the throat part 1b, and the opening area is gradually expanded again to form the outlet IC, which is shown enlarged in FIG. 3(a). As such, it is preferable that the inner circumferential surface is substantially parallel to the central axis at the outlet IC position. This is because the direction of the ejected flow is influenced to some extent by the direction of the inner circumferential surface of the outlet 1c, so the purpose is to make parallel flow as easy as possible. However, as shown in Figure 3(b),
If the angle α of the inner circumferential surface from the throat portion 1b to the outlet IC with respect to the central axis is set to 7° or less, preferably 5° or less, separation phenomenon is less likely to occur and the ejected flow is maintained almost uniformly. In this case, the reduction and expansion nozzle 1 can be easily manufactured by omitting the formation of the parallel part, which does not need to be parallel as in the case of L. Further, if the contraction/expansion nozzle 1 is made rectangular as shown in FIG. 3(C), it is possible to eject the liquid 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 1, the boundary layer between the inner surface of the contraction/expansion nozzle 1 and the flowing fluid becomes large and the flow becomes non-uniform. The faster 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 precision of the contraction/expansion nozzle l becomes lower. The inner surface of the contraction/expansion nozzle l conforms to JIS B 06.
01, three or more inverted triangular marks representing surface finishing accuracy, optimally four or more are preferred. especially,
The separation phenomenon at the enlarged part of the contraction/expansion nozzle l greatly affects the subsequent flow state, so the finishing accuracy is
By placing emphasis on this enlarged portion, it is possible to easily manufacture the contracting/expanding nozzle l. In addition, in order to prevent the occurrence of peeling phenomenon, the throat portion 1b is made into a smooth curved surface.
It is necessary to prevent the differential coefficient in the cross-sectional area change rate from becoming (1).

The material for the contraction/expansion nozzle l can be widely used, such as iron, stainless steel, other metals, acrylic resin, polyvinyl chloride, synthetic resins such as polyethylene, polystyrene, and polypropylene, ceramic materials, quartz, and glass. can. This material may be selected by taking into account non-reactivity with flowing components, workability, gas release properties in a vacuum system, and the like. Furthermore, the inner surface of the contraction/expansion nozzle 1 can be plated or coated with a material that is less likely to cause film adhesion or reaction. 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, the contraction/expansion nozzle l
As the flow passes, the thermal energy it possesses is converted into kinetic energy. In particular, when ejected at supersonic speed, the thermal energy is significantly reduced, resulting in a supercooled state. If the flow contains condensed components, it is also possible to actively condense them by the above-mentioned cooling state, thereby forming ultrafine particles. Further, in this case, in order to perform sufficient condensation, it is preferable that the contraction/expansion nozzle 1 is long. On the other hand, when the above-mentioned condensation occurs, 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.

The pressure ratio P/P of the pressure Po of the upstream chamber 2 on the upstream side and the pressure P of the downstream chamber 4 on the downstream side, and the ratio A/ of the opening area A'' of the throat portion 1b and the opening area of the outflow port IC. By appropriately adjusting the relationship with A'' and allowing the flow to flow through the contraction/expansion nozzle 1, the flow is formed into a beam and flows to the downstream chamber at an extremely high speed. Then, the film-forming components are sprayed onto the substrate 3 as a beam-formed flow to form a film. At this time, the base body 3 gradually rotates and many beams are irradiated onto the base body 3 due to the provision of a large number of upstream chambers 2, so that it is possible to form a film over a wide area at once.

In this embodiment, the plasma is generated by the cavity resonator 7, but as shown in FIG. Alternatively, as shown in FIG. 5, a horn antenna 14 can be connected. In these cases as well, a magnet may be provided near the exit so that the generated plasma can be drawn out efficiently. If microwaves are introduced through the slot antenna 13 or the horn antenna 14, the lengths of these antennas can be adjusted freely, making it easier to take out the plasma at a position closer to the contraction/expansion nozzle 1.

Further, in this embodiment, the base body 3 has a rotatable drum shape,
Although the upstream chamber 2 is provided in a spiral shape around this, the upstream chamber 2 may be provided in a planar, zigzag, or staggered manner by using the base body 3 as a movable plate, and the base body 3 may move horizontally in a straight line.

[Effects of the Invention] According to the present invention, it is possible to uniformly spray fine particles onto a large-area substrate 3 efficiently. Therefore,
It is expected that it will be used in the mass production of electrophotosensitive drums, magnetic recording tapes, magneto-optical recording tapes, etc.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing an embodiment of the present invention applied to a film forming apparatus, Fig. 2 is an enlarged sectional view of an upstream chamber thereof, and Figs. Figures 4 and 5 are diagrams showing other examples of the flow chamber. 1: contraction/expansion nozzle, 1a: inlet, Ib: throat, IC: outlet, 22 upstream chamber, 3: base,
4: downstream chamber, 5: pump, 6: opening, 7: cavity resonator, 8: microwave introduction window, 9: waveguide, 10a, 10b: supply valve, ll: magnet, 12: supply pipe, 13ni slot antenna. 14: Horn antenna.

Claims (1)

[Claims] 1) A plurality of upstream chambers for ejecting fine particles through contraction/expansion nozzles are provided so that the nozzles are directed toward a movable substrate, and adjacent upstream chambers are shifted from front to back and left and right in the direction of movement of the substrate. A fine particle spraying device characterized by: