JP3558970B2 - Ultrafine particle thin film forming method and apparatus - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a technique for depositing ultrafine particles of a brittle material on the order of submicrons on the surface of an object to form an ultrafine particle thin film. Such a technique can be applied to micromachines, fine processing techniques, mounting of semiconductor components, and ceramic coating.
[0002]
[Prior art]
Ultrafine particles of metal, ceramics, etc. are aerosolized by gas agitation and accelerated through a fine nozzle, or accelerated using an electric charge and an electric field gradient, and sprayed and collided on the substrate to deposit Conventionally, a technique for forming ultra-fine particles for forming fine functional components and device components has been known.
[0003]
【task to solve】
However, it is not always easy to control the film thickness with the conventional ultrafine particle deposition technology of this kind. In other words, the minimum thickness of the thin film to be formed is determined by the particle size of the ultrafine particles of the material constituting the thin film. Despite the need for ultrafine particles of commercially available materials that make up these thin films, many of them are on the order of microns, and ultrafine particles of materials on the order of submicrons or nanometers are not available. Not easy and expensive. For this reason, it is not always easy to form an ultra-thin ultrafine particle film.
[0004]
Next, in order to increase the strength of the thin film, it is necessary to improve the bonding between the ultrafine particles constituting the thin film, and for that purpose, the surface of the ultrafine particles must be a new active material free of dirt and water vapor However, in practice, it is difficult to keep the surface of such ultrafine particles newly active, and it is not always easy to maintain the strength of the thin film at a high level.
[0005]
Next, it is not easy to switch the ultrafine particles of the material constituting the thin film. Depending on the type of thin film, those that need to be composed of fine particles of material with a large particle diameter, those that need to be composed of fine particles of material with a small particle diameter, and those that combine large and small particle diameters Although it is desired to form a layer, it is difficult to select or switch such various particle sizes.
[0006]
The present invention has been made in view of the above circumstances, and can form a nanometer-order ultra-thin ultra-fine particle film, and also makes the surface of the material ultra-fine particles a new active material. It is an object of the present invention to provide a method and an apparatus for forming an ultra-fine particle thin film which can form a strong ultra-fine particle thin film of ultra-fine particle bonding and which can adopt various layer configurations of the ultra-fine particle thin film. Is what you do.
[0007]
[Means for Solving the Problems]
In response to this object, the method for forming an ultrafine particle thin film according to the present invention includes the steps of: forming a thin film having a thickness of the order of sub-μm or less by using ultrafine particles of a brittle ceramic material on a substrate; The reflective surface and the substrate are arranged, and the material fine particles are aerosolized and collided with the reflective surface, and then, using the mechanical pulverizing effect of the ultrafine particles generated at this time, activated ultrafine particles having a new surface are formed. It is characterized in that it is produced and adhered on the substrate under reduced pressure .
[0008]
An apparatus for forming an ultrafine particle thin film according to the present invention is an apparatus for forming a thin film of sub-μm order or less, comprising: a reduced-pressure deposition chamber; and an aerosol of ultrafine particles of a brittle ceramic material in the deposition chamber. and the aerosol supply device for supplying, and a said deposited arranged reflecting surfaces within the chamber, wherein by blowing the aerosol to the reflective surface from collide ultrafine particles to the reflective surface, occurs when the ultrasonic Using the mechanical pulverizing effect of the fine particles, activated ultrafine particles having a nascent surface are generated, and this is configured to adhere to a substrate disposed in the film forming chamber under reduced pressure. And
[0009]
Embodiment
Hereinafter, the details of the present invention will be described with reference to the drawings showing one embodiment.
In FIG. 1, reference numeral 1 denotes an ultrafine particle thin film forming apparatus. The ultrafine particle thin film forming apparatus 1 has a film forming chamber 2. A nozzle 3 is attached to the film forming chamber 2, and a vacuum pipe 4 and a vacuum pump 5 are connected. The nozzle 3 is connected to an aerosol generator 6 installed outside the film forming chamber 2. The vacuum pipe 4 and the vacuum pump 5 reduce the pressure inside the film forming chamber 2. A reflector 8 and a substrate 11 are mounted on a frame 7 in the film forming chamber 2. The reflector 8 and the substrate 11 are fixed to the frame 7 or the position thereof is variable.
[0010]
The reflector 8 has a reflection surface 12, and the incident side of the reflection surface 12 faces the nozzle 3. The reflecting surface 12 is a surface that collides and reflects the ultrafine particles of the material contained in the aerosol ejected from the nozzle 3, and the hardness of the reflecting surface 12 is configured to be greater than the hardness of the colliding ultrafine particles. The ultrafine particles used here are brittle ceramic fine particles such as oxides, carbides and nitrides, and have a particle size of the order of submicron or more. The substrate 11 faces the reflection side of the reflection surface 12. The substrate 11 is an object on which a thin film is formed, or is a support for supporting the formed thin film.
[0011]
Using the ultrafine particle thin film forming apparatus 1 configured as described above, an ultrafine particle thin film is formed by the following operation. The inside of the film forming chamber 2 is evacuated by operating the vacuum pipe 4 and the vacuum pump 5. In this state, the aerosol generator 6 is operated to mix the ultrafine particles of the material with a gas such as dry air or helium to generate ultrafine aerosol, which is then reduced in film by using the transport pipe 13. After being introduced into the chamber 2, the light is irradiated on the reflecting surface 12 of the reflector 8 made of a hard material through the nozzle 3 having a narrow opening. At this time, the ultrafine particles 21 colliding with the reflection surface 12 are crushed by the impact force of the collision and are changed to ultrafine particles 22 having a particle size of nanometer order and high surface activity. Thereafter, the pulverized ultrafine particles having a particle size on the order of nanometers fly and deposit on the substrate 11 placed in the vicinity of the reflection surface 12 to form a strong thin film having transparency. Since the flying position and the flying distance vary depending on the particle diameter of the ultrafine particles reflected by the reflecting surface 12, the particle diameter of the thin film formed on the surface can be selected by selecting the position of the substrate 11.
[0012]
【The invention's effect】
Conventionally, since the particle size of the ultra-fine particle material used is on the order of sub-μm, the thickness of the ultra-fine particle film is close to the particle size of the ultra-fine particles that first adhere to the substrate, and a thin film having a thickness of the order of sub μm is obtained. Although it was difficult, in the present invention, instead of spraying the ultrafine particles directly on the substrate on which the film was formed, it was once sprayed on a very hard reflecting surface such as diamond where film formation did not occur. Activated nanometer-order ultrafine particles with a nascent surface are generated using the mechanical crushing effect of the generated ultrafine particles, and deposited on a substrate to form a thin film with a fine crystal structure of sub-μm order or less. To achieve the formation.
[0013]
As is apparent from the above description, according to the present invention, a dense thin film having a thickness of submicron or less can be formed at a high speed by using raw material ultrafine particles of submicron to several micron order. This makes it possible to obtain a transparent thin film of a functional ceramic material such as ITO (transparent electrode material), TiO2 (photocatalyst), and PLZT (photostrictive material) by a method of spraying ultrafine particles.
[0014]
[Brief description of the drawings]
FIG. 1 is a diagram illustrating the configuration of an ultrafine particle thin film forming apparatus.
REFERENCE SIGNS LIST 1 Ultrafine particle thin film forming apparatus 2 Film forming chamber 3 Nozzle 4 Vacuum pipe 5 Vacuum pump 6 Aerosol generator 7 Frame 8 Reflector 11 Substrate 12 Reflective surface 13 Transport pipe 21 Ultrafine particles before collision 22 Ultrafine particles after collision

Claims (8)

When forming a thin film having a thickness of the order of sub-μm or less using ultrafine particles of a brittle ceramic material on a substrate, a reflecting surface and the substrate are arranged in a reduced-pressure deposition chamber, and the material particles are aerosolized to form the aerosol. After colliding with the surface, by using the mechanical crushing effect of the ultrafine particles generated at this time, activated ultrafine particles having a nascent surface are generated and adhered to the substrate under reduced pressure. For forming ultrafine particle thin film 2. The method for forming an ultrafine particle thin film according to claim 1, wherein the hardness of the reflection surface is higher than the hardness of the ultrafine particles colliding. 2. The method according to claim 1, wherein the size of the ultrafine particles before colliding with the reflection surface is larger than the thickness of the thin film. 2. The method according to claim 1, wherein a relative distance between the reflection surface and the substrate is variable. A film forming apparatus for forming a thin film of sub-μm order or less, comprising: a film forming chamber under reduced pressure; an aerosol supply device for supplying an aerosol of ultrafine particles of a brittle ceramic material into the film forming chamber; And a reflecting surface disposed on the reflecting surface, the aerosol is sprayed on the reflecting surface to cause the ultrafine particles to collide with the reflecting surface, and then, using a mechanical pulverizing effect of the ultrafine particles generated at this time, a new surface is formed. An apparatus for forming an ultrafine particle thin film , wherein the activated ultrafine particles are generated and adhered to a substrate disposed in the film forming chamber under reduced pressure. 6. The apparatus for forming an ultrafine particle thin film according to claim 5, wherein the hardness of the reflecting surface is configured to be higher than the hardness of the colliding ultrafine particles. The ultrafine particle thin film forming apparatus according to claim 5, wherein the size of the ultrafine particles before colliding with the reflecting surface is larger than the thickness of the thin film. 7. The apparatus according to claim 6, wherein a relative distance between the reflection surface and the substrate is variable.

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