JPS63264134A - Production of low molecular weight material by microwave - Google Patents

Abstract

PURPOSE:To produce a uniform thin film of low mol.wt. material on an adherend with good reproducibility by spraying a liquid substance in multistage microwave cavities equipped successively and reduced pressure, and passing the adherend through these cavities. CONSTITUTION:After equipping a porous object 24 in a reaction chamber 17, pressure of first-third microwave cavities 13a-13c and the reaction chamber 17 is reduced. At the same time, electric power is supplied to magnetrons 19a-19c to generate microwave in cavities 13a-13c. After that, the liquid substance such as an aq. soln. of silicic acid is supplied to the first cavity 13a through a nozzle 16 for prepg. corpuscle. In this cavity fine particules of the aq. soln. of silicic acid are evaporated and solidified into a cluster under low pressure by microwave. The cluster is introduced to the second cavity 13b to be pulverized by adsorbing the microwave and thereafter to the third cavity 13c to decompose into unimolecules finally. At that time, the output of magnetrons 19a-19c is controlled with a detector 22 according to the state. By this operation, unimolecules are effectively produced and adsorbed on the porous object 24 in a reaction chamber 17.

Description

DETAILED DESCRIPTION OF THE INVENTION [jI Industrial Field of Application 1 The present invention relates to a method for producing a low-molecular substance using microwaves.

[Prior Art] Conventionally, as a method for forming a thin film, for example, a method is known in which active species are generated by discharging a sample gas in a single chamber and coated on an adherend in the same chamber. Such film formation will be explained in detail with reference to the drawing in FIG. 111 in reaction chamber 1
12 and an adherend holder 3 are installed, and the adherend 4 is placed on the holder 3. The sample gas is introduced into the reaction chamber 1 from the gas inlet 5, and is discharged by a voltage applied between the electrode 2 and the adherend holder 3 to generate active species.

The generated active species are deposited on the surface of the adherend 4 to form [1, and the remaining gas is exhausted from the gas outlet 6.

[Problems to be Solved by the Invention] However, in the prior art, since active species are generated in a single chamber, there is a problem in that only gaseous samples or samples with high vapor pressure can be used as raw materials. In addition, the conditions for the generation of active species (
Because the reaction was performed with fixed values (pressure, flow rate, energy), etc., and the conditions were evaluated after analyzing the products, it was not possible to understand the changes in state during the reaction, and it was difficult to form a uniform thin film. was difficult.

The present invention was made in order to solve the above-mentioned conventional problems, and aims to provide a method capable of producing a uniform low-molecular substance (monomolecular substance) with good recyclability.

[Means for Solving the Problems] The first invention of the present application sprays a liquid substance into multi-stage micro-cavities that are continuously installed under reduced pressure, and allows the liquid substance to pass through the cavities, thereby vaporizing and reducing low-molecular-weight substances. This is a method for producing low-molecular substances using microwaves.

The second invention of the present application is to atomize #4 a liquid substance into a multi-stage microwave cavity in a reduced pressure state that is installed continuously, and by passing it through these cavities, it is vaporized and reduced to low molecular weight. This is a method of generating a low molecular weight substance using microwaves, which is characterized by irradiating a substance with microwaves to generate plasma.

Examples of the liquid substance include an aqueous solution of an acid, an alkali, or a salt, and a slurry of powder dispersed in water or a polar organic solvent. Note that it is also possible to use only gas as the raw material.

[Function] According to the first invention of the present application, by spraying a liquid substance into a multi-stage microwave cavity under a low pressure condition that is installed in succession, the particulate liquid substance is transmitted to the cavity at a frequency of, for example, 100. ~3000M lb, output 1
It absorbs microwaves of 0 to 200 W, heats up, and vaporizes. Next, the molecular assembly is dissociated into molecules (clusters) with a low degree of association in a cavity installed in the next stage. Furthermore,
Dissociates into single molecules in the next stage cavity. In this process, for example, when an NaCβ aqueous solution is used as a liquid substance, the state of dissociation progresses due to the absorbed microwave power, as shown in Figure 4, but even if high power is irradiated at once, fine particles of the liquid substance Molecules with a high degree of association remain, resulting in a state in which molecular species with a high degree of association are mixed. In the present invention, since microwaves are absorbed in stages, target molecular species can be efficiently generated.

At this time, if one of the microwave, infrared, visible, and ultraviolet absorption spectra is monitored through an optical window installed in the cavity and the type and concentration of molecules generated in the cavity are determined, based on this, the incident microwave It can be controlled so that a large number of molecular species for the purpose of electricity are generated. 7 Therefore,
By generating small molecules in stages, monitoring the concentration in real time, and feeding back the results to control the incident microwave power, the desired active species can be generated with high efficiency.

Further, according to the second invention of the present application, it is possible to further supply a microwave power (for example, 50 to 200 W at a pressure of 0.1 to 50 torr) that does not cause dielectric breakdown of the gas to the next stage of the microwave cavity described above. As a result, plasma is generated, and radicals and ions can be generated. At this time, if you monitor the emission spectrum, absorption spectrum of atoms and molecules, fluorescence spectrum, or Eman spectrum through the optical window installed in the cavity,
Based on this, the power of the incident microwave can be controlled so that many target molecular species are generated. Therefore, after generating small molecules in stages, plasma is generated, the concentration is monitored in real time, and the results are fed back to control the incident microwave power to generate the desired active species with high efficiency. can do.

[Embodiments of the Invention] Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 and 2.

Example 1 FIG. 1 is a schematic diagram showing an active species generator used in Example 1. 11 in the figure is a chamber, and this chamber 11 is divided by two slits 12a and 12b made of wire netting of 9 mesh or more, for example.
Third microwave cavities 13a-13c are formed. Further, 14 in the figure is a storage tank containing a 10% concentration silicic acid aqueous solution, and the silicic acid aqueous solution in this storage tank 14 is passed through a dosing pump 15 to an atomization nozzle 16 inserted into the first cavity 13a. through the cavity 1
3a.

A reaction chamber 17 is connected to the third cavity 13C, and each of the cavities 13a to 1 is connected to the reaction chamber 11.
3c and a vacuum pump 18 for bringing the reaction chamber 11 into a reduced pressure state are connected. Each of the cavities 13a to 13
Magnetrons 19a to 190 are provided in the upper part of the chamber 11 corresponding to 0, and these magnetrons 19a to 19c are provided with magnetrons [208 to 20
c is connected. These magnetron power supplies 20a~
20C is connected to a controller 21, and the power output to each of the magnetrons 19a to 19c is controlled by a signal from the controller 21. Furthermore, 22 in the figure is a detector, and this detection@22 monitors the infrared absorption of the third cavity 13c through an optical window 23 provided in the chamber 11 corresponding to the third cavity 13c. It is. The detector 22 is connected to a controller 21, and its detection signal is fed back to the magnetrons Ill 20a to 20c through the controller 21.

Next, a method for generating active species will be explained using the above-mentioned generator shown in FIG.

First, after installing a porous body 24 made of alumina or cordierite as an adherend in the reaction chamber 17, the vacuum pump 18 is activated to open the first to third microwave cavities 138 to 13C and the reaction chamber 17. 1 to 10tOrr inside chamber 17
At the same time, each magnetron electric current 1 [2
Electric power is supplied from 0a to 20c to the McNetrons 19a to 19c to generate microwaves in the first to third microwave cavities 13a to 13C of the chamber 11. Subsequently, the dosing pump 15 is operated to atomize the silicic acid aqueous solution in the storage tank 14 to 1 μm or less through the atomization nozzle 16, and supply the atomized solution into the first microwave cavity 13a. At this time, the atomized aqueous solution is evaporated in the first cavity 13a by evaporation at low pressure and absorption of microwaves, and the silicic acid is evaporated and solidified to form clusters (H4Si 04 ) 11
becomes.

Next, the clusters are guided to the second cavity 13b on the downstream side along the exhaust flow of the vacuum pump 18, and are atomized by absorbing microwaves in this cavity 13b. After this, the further refined clusters are guided into the third cavity 130 on the downstream side, where they absorb microwaves and are finally decomposed into single molecules (H4Si 04 ) or their oxides (SiO2). be done. At this time, the infrared absorption in the cavity 130 is monitored by the detector 22 through the optical window 23 of the chamber 11 corresponding to the third cavity 13C, and the ratio of single-molecule clusters is determined based on the half-width and intensity of the infrared absorption spectrum. The single molecule concentration and the dehydration process from silicic acid to oxidized silicic acid can be understood. By outputting the signal detected by the detector 22 to the controller 21, the controller 21 outputs the signal detected by the detector 22 to each magnetron power source 20a to 2.
0c, these power supplies 20a to 20
The outputs of the magnetrons 19a to 19c connected to 0 are controlled, thereby producing a single molecule (H4Si04) or its oxide (SiO2) with high efficiency.

Since this single molecule behaves as a gas under non-equilibrium conditions, it has extremely high activity, and in the process of flowing through the reaction chamber 11 installed downstream of the third cavity 13C,
The coating is uniformly adsorbed onto the surface of the porous body 24 made of alumina or the like placed on the surface.

In the first embodiment, infrared absorption was monitored by the detector 22, but microwave visible, ultraviolet absorption spectra, and Raman spectra were also monitored, and this detection signal was sent to the controller 21.
It may be fed back to the magnetron power supplies 20a to 200 through the power supply.

Example 2 FIG. 2 is a schematic diagram showing an active species generator used in Example 2. Reference numeral 11 in the figure is a chamber, and this chamber 11 has first to fourth slits partitioned by, for example, three slits 128 to 120 made of wire mesh of 9 or more meshes.
Microwave cavities 138 to 13d are formed. Further, 14 in the figure is a storage tank containing a 10% concentration silicic acid aqueous solution, and the silicic acid aqueous solution in this storage tank 14 is passed through a dosing pump 15 to a fine nozzle 16 inserted into the first cavity 13a. via the cavity 13a
sprayed inside.

A reaction chamber 11 is connected to the fourth cavity 13d, and each of the cavities 13a to 1 is connected to the reaction chamber 17.
3d and a vacuum pump 18 for bringing the reaction chamber 17 into a reduced pressure state are connected. Each of the cavities 13a to 13
Magnetrons 19a to 19d are provided at the upper part of the chamber 11 corresponding to d, and these magnetrons 19a to 19d are connected to magnetron power supplies 20a to 20.
d is connected. These magnetron power supplies 20a~
20d is connected to a controller 21, and the power output to each of the magnetrons 19a to 19d is controlled by a signal from the controller 21. Furthermore, 2 in the figure
2 is a detector, and this detector 22 monitors the molecular and atomic spectrum of the fourth cavity 13d through an optical window 23 provided in the chamber 11 corresponding to the fourth cavity 134. . Said detection @22
is connected to the controller 21, and its detection signal is connected to the controller 21.
It is fed back to each of the magnetron power supplies 20a to 20d through.

Next, a method for generating active species will be explained using the above-mentioned generator shown in FIG.

As in the first embodiment, the third microwave cavity 13
The low molecules generated in C are guided to the fourth microwave cavity 13d on the downstream side, where they are subjected to magnetron electricity! Ij20
By performing microwave discharge in accordance with d, low molecules are decomposed into ions or active elements. At this time, detection 8
22 monitors the ions or active elements in the cavity 13d as atomic and molecular spectra through the optical window 23 of the chamber 11 corresponding to the fourth cavity 13d, and outputs the detection signal to the IIIll device 21. From the controller 21 to each magnetron power source 20
a to 20d, and these power supplies 20a
The outputs of the magnetrons 19a to 19d connected to the magnetrons 19a to 20d are controlled, thereby generating ions or active species with high efficiency. These ions or active species have extremely high activity, and as they flow through the reaction chamber 17 installed downstream of the fourth cavity 13d, they are uniformly distributed over the surface of the porous body 24 made of alumina or the like installed in the reaction chamber 11. is adsorbed to form a coating.

In Example 2, the detector 22 monitored ions or active elements as atomic and molecular spectra, but emission spectra, absorption spectra (microwave, infrared, visible, ultraviolet), laser organic fluorescence spectra, or Raman The spectrum may be monitored and this detection signal may be fed back to the magnetron power supplies 20a to 20d through the controller 21.

[Effects of the Invention] As detailed above, according to the method for producing small molecules using microwaves of the present invention, small molecules can be produced stepwise by successively installed multi-stage microwave cavities under reduced pressure, or
Alternatively, after generating small molecules and further generating plasma, the concentration is monitored in real time, and the results are fed back to control the incident microphone D-wave power, thereby generating the desired active species with high efficiency. I can do it,
Furthermore, it can be effectively used for *S growth of semiconductor thin films, gas fractions, oxide films, etc., surface modification of adsorbents, catalysts, etc., amorphous films used in solar cells, plasma etching, and ultrafine particle generation. It has a great effect.

[Brief explanation of drawings]

Figure 1 is a schematic diagram showing the active species generator used in Example 1 of the present invention, Figure 2 is a schematic diagram showing the active species generator used in Example 2 of the present invention, and Figure 3 is a schematic diagram showing the active species generator used in Example 2 of the present invention. FIG. 4 is a schematic diagram showing a conventional IL film forming apparatus, and is a characteristic diagram showing a series of processes in which an NaCl aqueous solution absorbs microwaves and is vaporized, reduced in molecular weight, atomized, and ionized. 11...Chamber, 13a-13d...1st to 4th
microwave cavity, 16... atomization nozzle, 1
7... Reaction chamber, 18... Vacuum pump, 19a-19
d... Magnetron, 20a-20d... Magnetron power supply, 21... Controller, 22... Detector, 23
...optical window, 24...porous body. Applicant's agent Patent attorney Takehiko Suzue Figure 3

Claims (4)

[Claims] (1) A low-molecular substance using microwaves, characterized in that a liquid substance is sprayed into a series of vacuum cavities in a multi-stage microwave cavity, and the substance is vaporized and reduced in molecular weight by passing through these cavities. How to generate. (2) A low-molecular substance produced by microwaves is monitored by a spectroscopic method, and the microwave power to the multi-stage microwave cavity is controlled. How to generate. (3) Liquid substances are sprayed into cavities with multi-stage microwaves under reduced pressure that are installed continuously, and by passing through these cavities, they are vaporized and reduced to low molecular weight substances. A method for producing low molecular weight substances using microwaves, which is characterized by irradiating with microwaves and generating plasma. (4) Generation of low-molecular substances by microwaves according to claim 3, characterized in that the generated plasma is monitored by a spectroscopic method and the microwave power for irradiating the microwaves is controlled. Method.