JP2003245540A - Method for manufacturing ultrafine particle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method capable of easily manufacturing ultrafine particles of a multi-element composition comprising two or more elements and manufacturing the ultrafine particles in an isolated and dispersed state without aggrogation even when dried after concentration or coating. <P>SOLUTION: The method for manufacturing the ultrafine particles includes a process for applying a target substance on the surface of a flowing liquid by vapor deposition to obtain a liquid containing particles, and a process for substituting the liquid with a solvent to obtain the particles. <P>COPYRIGHT: (C)2003,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] The present invention relates to a method for producing ultrafine particles.
Regarding the law. The present invention also relates to semiconductors, phosphors and various recording materials.
Related to materials, electronic functional materials, bio-related functional materials, etc.
The present invention relates to a method for producing ultrafine particles. Ultra fine particles as used in this specification
Is an average particle size in the range of 1 nm to 50 nm.
No-size particles. [0002] Conventionally, various methods for producing ultrafine particles have been used.
The average particle size is several tens of nanometers.
So-called nanoparticles of less than a meter
Scratches are made using the build-up method. Build
The up method is a liquid phase method represented by precipitation and desolvation methods.
And gas phase methods such as evaporative condensation method and gas phase reaction method.
being classified. As a liquid phase method, for example, JP 2000-5A
No. 4012 discloses a metal, an intermetallic compound by a reduction method,
A technique for forming magnetic nanocrystals of alloys is disclosed.
Yes. According to the liquid phase method including this method, it is relatively uniform.
Ultrafine particles with a single particle size can be obtained, but the raw materials are
Must be dissolved as a stoichiometric pair
There are limitations such as the ability to produce only a compound with a composition ratio. On the other hand, the vapor phase method is relatively easy to form a thin film.
However, it is further necessary to collect in the form of nanoparticles.
Consideration is necessary. For example, JP 2001-35255 A
Introduced silver or oxygen by the gas evaporation method
To obtain silver oxide nanoparticles. More
As a method to obtain highly pure particles
Grouth 45 (1978) 490-494, Vapor deposition on fluid oil surface (VE
ROS method) is introduced. The evaporation source in this case is resistance
Overheating or electron beam is used. Only
Even though both are suitable for single element particle formation,
It is difficult to produce nanoparticles composed of the above elements. More
It is effective when it becomes multi-element nano particles of arbitrary composition ratio
The fact is that there is no simple manufacturing method. The above VEROS
The method requires the use of low vapor pressure oil, but
Use heat to concentrate or collect the colloidal particles.
It is known to concentrate in vacuo over time. But this person
In the method, the particles dispersed and dispersed by heating are aggregated
The particles are effectively used together.
There is a problem that you can not. [0005] SUMMARY OF THE INVENTION The object of the present invention is binary.
It is relatively easy to produce even ultra-fine particles of more than elementary elements.
Can be manufactured, and even after drying after concentration or application
Good ultrafine particles isolated and dispersed
The object is to provide a method by which a construct is obtained. [0006] [Means for Solving the Problems] The present inventors have intensively studied.
As a result, the following objects of the present invention can be achieved.
And found. (1) Deposit the target material on the flowing liquid surface
A step of obtaining a liquid containing particles, and the liquid as a solvent
Including a step of obtaining particles by substituting
Particle production method. (2) Target material flying by sputtering
The vapor pressure at 25 ° C. is 10^-FiveFlow below Torr
Vapor deposited on the oil surface and obtained from the target material
After collecting the oil containing the particles,
10^-FiveReplace with a solvent having a higher vapor pressure than Torr
A process for producing ultrafine particles, comprising the step of: (3) Use of an ultrafiltration membrane to replace the solvent
(1) or (2), characterized in that
A method for producing the ultrafine particles described above. (4) Substitution of the solvent is such that the vapor pressure at 25 ° C. is 1
0^-FiveExtract and remove oil below Torr using methanol
And after collecting the particles at high concentration, 10% at 25 ° C. ^-FiveTo
redispersion in a solvent having a vapor pressure higher than rr.
(1) or (2), characterized in that
A method for producing the ultrafine particles described above. (5) In addition to containing particles obtained from the target substance
A first solvent that can be dissolved in the recovered oil;
A second solvent that is difficult to dissolve in the first solvent, and the second solvent
Selective removal of oil in recovered oil with solvent
Then, the dispersion medium of the particles is replaced with the first solvent from the oil.
The method for producing ultrafine particles as described in (2) above,
Law. (6) When replacing the above solvent, 10^-Five
Dispersing agent in a solvent having a vapor pressure higher than Torr
The upper content is in the range of 1 to 10% by mass.
Production of ultrafine particles according to any one of (1) to (5)
Manufacturing method. [0008] BEST MODE FOR CARRYING OUT THE INVENTION In the following, the ultrafine particles of the present invention
The manufacturing method will be described in detail. In this specification,
"~" Means the numerical value described before and after the lower limit and
And is used to include as an upper limit. Generally known
Is the vapor deposition method on the fluid oil surface the resistance overheating method used as the evaporation source?
The electron beam method is used. However,
In these cases, using multi-element target materials will cause vapor
Since the timing of evaporation shifts according to the pressure difference,
It becomes a particle of a single element instead of a particle. In the present invention
According to the first, by using a sputtering method as the evaporation source,
Elemental particles can be formed, and secondly, the
Normal multi-element particles fly even in the presence of
Can be able to. Third,
The resulting ultra-fine particle-dispersed oil is dissolved at a higher vapor pressure.
Substitution with a medium can facilitate concentration and drying. The target material used in the present invention is usually
Metals, metal oxides or sulfides used in
Various composites as well as silicon and its oxides
Materials can also be used. For example, silver, gold, copper,
Lead, iron, cobalt, chromium, nickel, aluminum,
Furthermore, chalcogens such as indium, antimony and tellurium
Effective in compounds and their composites
The Also, use general phosphor materials and semiconductor materials.
You can also. Specifically, Zn, Sr, Cd, Ca, Z
nMg, CaGa₂, BaAl₂Sulfides such as Ga, C
aGa₂, Y, Ge, CaGe, ZnGa₂, MgGe,
Sn, Y₂Ge, Zn₂Si, BeGa₂, Y₂Such as Si
Oxides, as well as Se, Te, As, Sb, Bi, P
Listed as a mixture semiconductor of elements such as b
be able to. Of these, SrS and CaGa are preferable.₂
S_Four, ZnS, BaAl₂S_Four, CaS, Y₂O₂S, Y₂O
_Three, CaGa₂O_Four, Ga₂O_ThreeIt is. Especially stoichiometrically
Even in the production of multi-element particles with a composition ratio that does not hold,
The effect of light is fully obtained. The oil that forms the fluid oil surface used in the present invention.
The vapor pressure at 25 ° C.
Vapor pressure refers to the vapor pressure at 25 ° C.
10)^-FiveTorr or less is required. Vapor pressure
10^-FiveEspecially for oils below Torr, the boiling point is 2
It is preferable to use silicone oil at 00 ° C or higher
Yes. Also, hydrocarbons with 6 or more carbon atoms, high boiling alcohol
Can also be used. The vapor pressure is 10^-FiveFor oil below Torr
Can contain various additives. For example,
Alkyl phosphine oxide, alkyl phosphite
Or -SH, -CN, -NH₂, -SO₂O
H, -SOOH, -OPO (OH)₂-COOH content
Compounds such as alkylphosphine.
Oxide, -SH or -COOH-containing compounds are preferred
That's right. In the method of the present invention, the flying target object
After collecting the oil containing quality, the oil
10^-FiveIt is preferable to replace with a solvent higher than Torr.
Yes. Vapor pressure is 10^-FiveAs a solvent higher than Torr, concrete
In particular, toluene, xylene, hexane, heptane,
Can, acetonitrile, or alcohol with 6 or less carbon atoms
Can be mentioned. Use a solvent such as toluene.
If it is applied, for example, it will erode the substrate when applied to a resin substrate.
After the above replacement depending on the application, further
A hydrophilized colloid may be produced by substitution. this
Especially when mixed with water or alcohol in any composition ratio
By selecting a possible solvent as the primary replacement solvent,
The toid is easier to make. In addition, the above various accessories
Additives can be contained in these substitution solvents. Flow
Dispersion stability is relatively good in the oil that forms the fluid surface.
When there is no aggregation even without additives such as dispersants
There is. Therefore, in this case, depending on the application,
Improve workability by including only suitable dispersants
Can. As the dispersant used here, for example,
Polyoxyethylene (4,5) lauryl ether acetic acid and
Carboxylic acids such as polyacrylic acid, polyoxyethylene
(1) Lauryl ether phosphate, dodecanethiol, etc.
Thiol compounds, pyridine, oleic acid, oleyl
Min, etc., but are not limited to these
Absent. Moreover, the usage-amount of a dispersing agent is 0.1-10 mass of a solvent.
% Is preferable, and 0.5 to 6% by mass is more preferable. The vapor pressure of the oil that forms the fluid oil surface is 1
0^-FiveStable sputtering when higher than Torr
The degree of vacuum required to perform the process may not be obtained.
The vapor pressure of the solvent to be replaced is 10^-FiveFor Torr or less
When storing colloidal liquid with ultrafine particles dispersed
However, drying after application is difficult.
The Vacuum heating is effective for drying.
It was found that the dispersed ultrafine particles were easily fused and aggregated.
This is especially likely when the particle size is small.
Because of the nano-size effect (surface effect)
it is considered as. Therefore, it is a solvent that can be easily dried in vacuum at room temperature
Substituting for is said to be an important process for device development later.
Yeah. As a solvent replacement method, for example, a spatula is used.
After diluting the oil recovered during the tulling with a replacement solvent,
Concentrate using an outer membrane and dilute the concentrate with a replacement solvent.
And replace the solvent by repeated filtration.
Can be adopted. Also by centrifugation
Allow the particles to settle and separate from the oil, then place the particles in the desired solvent.
It is also possible to redisperse. Furthermore, the target
To the recovered oil containing the particles obtained from the substance
A first solvent that can be dissolved and is difficult to dissolve in the first solvent
The second solvent is mixed, and the second solvent is used in the recovered oil.
By selectively extracting and removing the oil, the particle dispersion medium is oil
To the first solvent. These methods
Is preferable for stably dispersing ultrafine particles. The above
As the first oil used in the method, hepta
Decane, dodecane, etc., and the second oil
For example, methanol is preferable. In the present invention, the obtained oil is added with methanol.
By adding an appropriate amount of oil, only the oil that is the dispersion medium
It was found that it can be selectively extracted and removed.
Is a particularly simple and excellent method. In other solvents
When oil cannot be extracted or particles cannot be separated
Most of the time. In the present invention, the flying target material is flowed.
It is preferred to deposit on the moving oil surface. oil
As a flow method, a disk-shaped substrate is rotated at high speed.
And supply oil near the center of rotation to generate centrifugal force.
It is preferable to adopt a method that allows the fluid to flow evenly on the disk.
Yes. The rotation speed of the substrate is preferably 10rpm ~ 500rpm
That's right. The oil should not be interrupted near the center of rotation.
It is preferable to supply continuously. The oil supply speed is
0.01 ml / min to 2 ml / min per unit area of the substrate
preferable. The fluid oil surface is the upper surface of the rotating substrate (in this case the spa
The lower surface of the cutter) or the lower surface (in this case the sputter is
Can be formed in either direction, but the falling of fluid oil
It is preferable to form on the upper surface of the rotating substrate to prevent the
Good. Conventionally known as VEROS method
Is a method of forming an oil surface on the lower surface of the rotating substrate.
If the number of revolutions of the plate is low or depending on the physical properties of the liquid,
There are problems such as contamination by falling on the source. But steam
The downward irradiation of the source is combined with spatter according to the present invention.
If so, good performance can be obtained. The fluid oil surface may be formed on an inclined surface.
Yes. In this case, the oil spreads over the entire inclined surface.
It is necessary to supply oil. Oil below the slope
Collected at the end. Both rotating substrate method and inclined plate method
The il may be circular. That is, it is collected by the collection unit
Circulate the oil again to the supply section to make sure that the particles have a certain concentration.
Can be used continuously. The substrate used in these methods is metal or
Those that have been processed smoothly with resin are preferred.
The material suitable for the can be selected. Especially on the substrate
A thin film of oil is uniformly formed and flows at a certain speed
It is desirable to select a material suitable for this. For this reason,
In order to control the substrate surface tension,
It is preferable to perform surface treatment. In the present invention, the substrate is cooled and sputtered.
Freeze traps and collects flying particles flying out
be able to. Substrate cooling is liquid nitrogen, liquid carbon dioxide
It can be performed using a cooling medium such as elemental or supercooled water. Base
When cooling the plate, the flight jumped out by sputtering
Bringing the particles into contact with the vaporized medium in the chamber
Is preferred. The medium to be vaporized is a solvent having a relatively low boiling point.
For example, an organic solvent having a boiling point of 200 ° C. or lower, preferably
An organic solvent having a boiling point of 150 ° C. or lower is preferable.
Lecoles are preferred. Flying particles are used with these vaporized solvents.
Cooling is promoted by contact, adsorbs on the surface, and on the substrate
Freeze-deposit with the solvent. Effect of adsorption protection on solvent surface
Prevents coalescence with particles that jump in later
Good particles with small size and narrow particle size distribution
Be able to get. Further to the flying particle surface
Adsorbents with different adsorptive power are mixed and exist in the vacuum chamber.
It is also preferable to be present. As the adsorbent, alkylphosphine oxy
Side, alkylphosphine, or -SH, -C
N, -NH₂, -SO₂OH, -SOOH, -OPO
(OH)₂, -COOH-containing compounds are effective,
Of these, alkylphosphine oxide and -SH
Or a -COOH containing compound is preferred. More lipophilic
Adsorbents include octyl, decyl, dodecyl,
A total of 6 or more carbon atoms such as a xadecyl group, preferably 8
Using adsorbent compounds with ~ 40 substituents
it can. The hydrophilic adsorbent has 6 or less carbon atoms.
Or a hydrophilic group (for example, -SO_ThreeM → -COOM
(M is hydrogen atom, alkali metal atom, ammonium molecule
It is preferable to use an adsorptive compound having
Good. The surface of the particles is modified with an adsorbent compound.
It is a grain with high resolution TEM such as FE-TEM.
There is a certain distance between the children and it is confirmed by chemical analysis.
It can be recognized. Preferred apparatus for carrying out the method of the present invention.
An example will be described with reference to FIG. The device of FIG.
A rotatable substrate 2 is disposed in the empty chamber 1. Foundation
The inside can be cooled with a cooling medium. Cooling medium (for example,
Liquid nitrogen) is supplied from the 8 inlet pipes. Substrate rotation
Is controlled by the motor 7 and the oil tank 6
Oil is supplied onto the substrate through the oil introduction pipe 5
The At this time, the oil is deaerated in advance through a vacuum exhaust pipe.
Oil is supplied continuously near the center of the rotating substrate.
And evenly flowed on the substrate. Sputter target 4
Arrange the necessary composition prepared by firing in advance and spatter
At the beginning of the ring, the surface oxide is removed and then shut down.
Particle 3 is opened and particle production is started. Fluid oil level on substrate
The flying particles that jumped into the
To the outer periphery, and the protective plate 9 and the recovered oil conduit 10
And collected in the recovered oil tank 11. Recovered
Particle-containing oil has a vapor pressure of 10^-FiveSolr above Torr
Is replaced by The composition of the particles that can be produced by the method of the present invention is:
Any composition and composition that allows sputtering
It is possible to produce by ratio. It also forms a fluid oil level
The oil has a vapor pressure of 10^-FiveReplace with a solvent of Torr or higher
In the case of solvents below this vapor pressure,
Concentration efficiency is significantly reduced, or heating and vacuum drying
At times, there is an adverse effect that particles are united. The present invention replaces
A suitable vapor pressure has been found, and further heating is performed.
Oil that can be used under vacuum conditions without melting
A method of replacing with a medium is provided. The vapor pressure of the present invention is 10^-FiveMore than Torr
Ultrafine particles dispersed in a medium are collected as colloids in organic solvents.
Can be handled. Or replace it with a hydrophilic solvent
It may be used as a hydrated colloid. These colloids
Can be spin coated or web coated
The [0025] The following examples further illustrate the features of the present invention.
This will be specifically described. The materials, amounts used, and
The ratio, processing content, processing procedure, etc. depart from the spirit of the present invention.
As long as there is not, it can change suitably. Therefore, this departure
The scope of light is limitedly interpreted by the specific examples shown below.
It shouldn't be. Example 1 As a sputtering target
Fabricate ZnS by baking, 4 inch backing plate
Set. Create a hollow substrate with a diameter of about 30 cm,
450 rpm rotation with a motor while cooling with cooling water
It was rotated at the rotation speed. Silicone oy as fluid oil
Le (HIVAC F4, manufactured by Shin-Etsu Chemical Co., Ltd.) (vapor pressure 10^-8
Torr) after degassing, rotating substrate at a supply rate of 5 ml / min
Fed on. RF high-rate power source for sputtering equipment,
Using a 4-inch planar magnetron type cathode, vacuum
The condition is a diffusion pump and a rotary pump.
Formed using. About 30 minutes from the start of particle production
Tulling was done. About 130 ml of oil is recovered,
Use the transmission electron microscope TEM to disperse the particles dispersed in it.
I confirmed that nano particles with an average particle size of 2 to 5 nm
Particles were confirmed. Furthermore, the composition in one particle is changed to EF-TE.
When confirmed with M, the presence of Zn and S was confirmed.
did it. Next, about 100 ml of the recovered oil is added to
After adding 150 ml of EN, use an ultrafiltration device to make Ar
Concentrated to about 20 ml at gas pressure. Then 200
Add ml of toluene and filter in the same manner until about 20 ml.
Concentrated with. This operation is repeated 5 times and finally about 10
Colloid-1 was obtained by concentrating to ml. Same
Sputtering is performed again using the method described above.
Yield oil was obtained. Next, add 100 ml of recovered oil to the
Add 200 ml of ethanol and stir well.
Remove the ethanol phase and add 200 ml of methanol again.
In the same manner, stirring was removed. Repeat this operation 5 times
The colloidal liquid is pasty with a volume of about 1 ml or less
It became a solid. Add a small amount of heptane to redisperse
As a result, colloid-2 was obtained. The colloid-1 and colloid-2 are
It spin-coated on the glass substrate. Vacuum dry at room temperature
As a result, an ultrafine thin film was obtained. The colloid is TEM
Vacuum-dried on the observation grid and observed by TEM
B) Well-dispersed average particle size without coalescence
It was confirmed that the particles were 2 to 5 nm in size. (Example 2) Sputtering target of Example 1
The Ga₂O_ThreeTo the fluid oil level as in Example 1.
The oil is recovered by sputtering with the method of forming
did. 100m of methanol to 100ml of recovered oil
1 and 10 ml of decane were added and stirred.
The solvent phase was removed. Here methanol dissolves in decane.
It is difficult to mix properly with silicone oil.
On the other hand, decane has the property of being mixed with silicone oil. this
Repeat the method 8 times to obtain about 5 ml of decane solution
Id-3) was obtained. This colloid-3 is the same as in Example 1.
Easy to vacuum dry at room temperature after spin coating
I understood it. The particle size obtained here is about
It was 2-4 nm. (Embodiment 3) In Embodiment 2, the recovery oy
100 ml of methanol, 100 ml of methanol and 5 ml of decane
And about 0.5 ml of oleylamine,
The oil was stirred and colloid-4 was obtained. The above alloy
Room temperature so that -4 and colloid-3 have the same concentration
As a result, the colloid-3 is about 3 days.
Slight agglomeration occurred, while colloid-4 was 1 week
It did not change even after a while. [0031] According to the manufacturing method of the present invention, two or more elements are used.
Even relatively simple multi-element ultrafine particles can be produced
be able to. Also, it can be united even if it is concentrated or dried after application.
To produce excellent ultrafine particles isolated and dispersed without
it can.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing an example of an apparatus for carrying out the manufacturing method of the present invention. [Explanation of Symbols] 1 Vacuum chamber 2 Rotating substrate 3 Shutter 4 Sputter target 5 Oil supply pipe 6 Oil tank 7 Motor 8 Coolant introduction pipe 9 Substrate outer periphery protection plate 10 Recovery oil conduit 11 Recovery oil tank

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4G075 AA27 BB02 BB05 BB08 BC02                       BD03 BD17 BD24 BD26 CA03                       CA51 CA65 DA02 DA13 EA01                       EA06 EB01 EB37 EC06 ED08                 4K017 AA03 BA01 BA02 BA03 BA04                       BA05 BA06 CA08 DA01 DA03                       DA09 EF05 EF10 EG01                 4K029 AA01 BA43 BA51 CA05

Claims (1)

1. A method of obtaining a liquid containing particles by depositing a target material on a flowing liquid surface, and a step of obtaining particles by substituting the liquid with a solvent. A method for producing ultrafine particles.