JPH01116081A - Manufacture of thin functional ceramics film - Google Patents

Abstract

PURPOSE:To manufacture a thin functional ceramics film by simple equipment by forming an aqueous or organic-solvent solution of inorganometallic salts and organometallic salts, dispersing the above solution into fine drops in a heating atmosphere to carry out thermal decomposition, and the depositing the above on a substrate. CONSTITUTION:One or >=two kinds among inorganometallic salts and/or organometallic salts soluble in water or organic solvents (alcohol, acetone, etc.) are dissolved in water or organic solvents. Further, the metallic elements include the elements located on the left side of a line connecting B and At in a long period-type periodic table, excluding hydrogen, and also include the various elements located on the line connecting B and At. Subsequently, the resulting solution is dispersed into fine drops in a heating atmosphere and deposited, in the course of or directly after the thermal decomposition of solutes, on a substrate. By this method, the thin functional ceramics film can be obtained by simple equipment at a low running costs.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a method for producing a functional ceramic thin film,
More specifically, thin films with electromagnetic functions such as conductive thin films, resistive thin films, magnetic thin films, piezoelectric thin films, thin films with optical functions such as photomasks, non-reflective/reflective films, selective absorption films, and corrosion-resistant and wear-resistant films. , relates to a method for producing a functional ceramic thin film such as a thin film having mechanical and chemical functions such as a heat-resistant film.

(Conventional technology) Functional ceramic thin films are usually formed on a substrate,
As described above, this thin film can be manufactured to have various functions, and many methods for manufacturing the same are known. Their manufacturing methods are broadly classified into physical methods, chemical methods, and physicochemical methods that are a combination of these methods.

If physical methods are further classified, the main one is physical vapor deposition (PVD).
X A thermal evaporation method, also known as a vacuum evaporation method, in which a thin film material is heated and evaporated in a high vacuum with a pressure lower than 10-6 Torr, and the evaporated particles are deposited on a substrate to form a thin film, resistance heating, high frequency heating, or heating by electron impact. The thin film material or its constituent substances are evaporated into a vacuum containing an inert gas such as argon or an active gas such as oxygen or nitrogen, ionized by DC discharge, RF discharge, electron impact, etc., and accelerated by electrolysis. There are ion blasting methods in which materials are deposited on a substrate as they are or by reacting with atmospheric gas, and sputtering methods in which materials are deposited on a substrate with materials that are blown away from the target in atomic or molecular form by accelerated ions. Examples include epitaxy, electrostatic spraying, and various coating methods.

Further, a typical chemical method is a chemical vapor deposition method in which a thin film is formed by chemically reacting gaseous raw materials in the gas phase or on the surface of a substrate.

Typical physicochemical methods that combine the above methods include plasma chemical vapor deposition, laser photochemical vapor deposition, and the like.

(Problems to be Solved by the Invention) As mentioned above, various methods have been proposed and put into practical use as methods for producing functional ceramic thin films, but these methods require large auxiliary equipment or are expensive. There are various problems such as those that require a vacuum system, those that have high running costs, and the inability to form a uniform thin film when trying to obtain multi-component ceramics. It is desired to develop a manufacturing method that can obtain a thin film with a uniform composition even if it is based on a component type.

(Means for Solving the Problems) As a result of research conducted by the present inventors to solve the above problems, the present inventors have found that a simple device has low running costs and can be easily applied to multi-component ceramics. We have discovered that it is possible to produce functional ceramic thin films, and have completed the present invention.

That is, the present invention provides a method for producing a ceramic thin film, in which one or more inorganic metal salts and/or organic metal salts soluble in water or an organic solvent are dissolved in water and/or an organic solvent. This is a method for producing a functional ceramic thin film, which is characterized in that the functional ceramic is dispersed in a heated atmosphere in microscopic shapes and deposited on a substrate during or immediately after the thermal decomposition process of a solute.

The metal elements constituting the inorganic metal salt and organic metal salt used in the present invention include not only metal elements (elements located to the left of the line connecting boron and ascutin in the long-period table, excluding hydrogen), but also It includes semimetallic elements (elements located on the line connecting boron and ascutin in the long periodic table). Specifically, metal elements include beryllium, magnesium, aluminum, calcium, barium, strontium, titanium, vanadium,
Examples include chromium, manganese, iron, cobalt, nickel, copper, zinc, yttrium, lanthanum, europium, zirconium, silver, cadmium, tin, nitride, lanthanum, and tungsten, as well as semimetallic elements such as boron and silicon. Examples include.

Inorganic metal salts composed of these metal elements include chlorides, bromides, iodides, nitrates, sulfates, phosphates, carbonates, phosphates, thiocyanates, and thiosulfates. etc. are used. In addition, organic metal salts include salts of carboxylic acids such as acetate, laurate, stearate, and oxalate, metal alkoxides, β-diketones, β-ketoesters, β-ketoamines, alkanolamines, and ethylenediamines. Chelates of etc. and metal elements are also used. The above metal salt may be a double salt.

Inorganic metal salts generally dissolve well in water. The solvent for dissolving the inorganic metal salt or organic metal salt is appropriately selected based on the solubility, reactivity, etc. of the metal salt used, and is not particularly limited as long as it dissolves the metal salt used and does not cause a significant reaction. Water, various organic solvents, or mixtures thereof can be used, but in order to simplify the apparatus and reduce running costs, a combination of an inorganic metal salt and a solvent mainly composed of water is preferred. As the organic solvent, a hydrocarbon solvent such as alcohol, acetone, or benzene is used.

There are no particular restrictions on the method of dispersing this metal salt solution in a minute shape in the space, but methods include using a general sprayer such as a two-fluid nozzle or a pressurized nozzle, or using a rotating disc to disperse the liquid using centrifugal force. Examples include a method of forming droplets by scattering, and a method of generating droplets by vibrating the liquid surface with an ultrasonic vibrator. This solution dispersed in the form of microdroplets is introduced into a heated atmosphere using a suitable carrier gas if necessary, but this heating atmosphere is particularly limited if it is heated to a temperature at which the solute is thermally decomposed. Instead, any method such as heater heating, infrared heating, etc. can be used.

As the heating atmosphere, an oxidizing gas, an inert gas, etc. are used, but when forming an oxide-based ceramic thin film, it is preferable to use an oxidizing atmosphere of air or oxygen.

When the droplet-like particles of the solution pass through a heated atmosphere, the solvent evaporates and becomes solute particles, which are then thermally decomposed by heating to become ceramic particles, which are then deposited on a substrate placed in or immediately after the heating atmosphere. is deposited in Any substrate can be used as this substrate as long as it has the necessary heat resistance, does not interact unfavorably with the functional ceramic to be formed, and has good adhesion to the functional ceramic. Although it is appropriately selected depending on the ceramic, various ceramic substrates, glass materials, etc. are common.

This substrate can be produced by a batch method in which the substrate is fixed in or immediately after the heating atmosphere to form a thin film, or it can be produced by a continuous method in which a large number of substrates are moved and a thin film is continuously formed. You can also do that.

The density of the thin film formed on the substrate is mainly determined by the temperature of the heating atmosphere and the position of the substrate.The higher the heating atmosphere temperature is, the shorter the distance between the substrate and the pore temperature range of the heating atmosphere, the more sintered A dense film is formed, and the position of the substrate is appropriately set depending on the degree of density required. The thin film may be sintered after formation to improve its density.

In addition, the film thickness is determined by the droplet generation rate, the carrier gas flow rate, the contact time for a fixed type substrate, and the movement speed for a continuous type. The density and thickness of the thin film can be controlled as desired.

The droplet generation speed can be controlled by the supply flow rate of the liquid when the droplets are generated using a two-fluid nozzle, or by the amplitude and frequency of the ultrasonic vibrator when the droplets are generated using an ultrasonic atomizer. can.

According to the present invention, a sufficiently dense ceramic thin film can be obtained even if the temperature in the heated atmosphere in which the substrate is placed or immediately after it is not so high, and the temperature is high enough to sinter a pressure-molded ceramic fine powder. The temperature is much lower than the required temperature. This is thought to be due to the fact that in the present invention, the ceramic thin film is generated by thermal decomposition and is therefore easily sintered.

According to the present invention, thin films having electromagnetic functions such as conductive thin films, resistive thin films, magnetic thin films, and piezoelectric thin films can be manufactured, such as conductive thin films made of tin oxide, magnetic thin films made of iron oxide, or barium titanate thin films. A piezoelectric thin film consisting of

Furthermore, a ceramic thin film is produced using three components consisting of one or more rare earth elements, one or more alkaline earth metals, and copper as metal elements constituting the inorganic metal salt and/or organic metal salt. When manufacturing a thin film with superconductivity, it is possible to obtain a thin film with superconductivity. In addition, we manufacture thin films with optical functions such as photomasks, non-reflective/reflective films, and selective absorption films, and thin films with mechanical and chemical functions such as corrosion-resistant, wear-resistant, and heat-resistant films made of alumina or magnesia. be able to.

EXAMPLES Hereinafter, the present invention will be specifically explained using examples. The present invention is not limited only to these examples.

Example 1 A mixed aqueous solution of yttrium nitrate, barium nitrate, and copper nitrate was used as a raw material solution, the molar ratio of yttrium, barium, and copper was 1:2:3, and the molar concentration of all metal ions in the aqueous solution was 0.04. It was set to mol/1.

Ultrasonic atomization was used to generate droplets, and the frequency of the ultrasonic vibrator was 1.5 MHz. Oxygen gas was used as a carrier gas at a flow rate of 15β/min, and the resulting droplets were sent into a heated atmosphere using this carrier gas.

The heating atmosphere was composed of a 1 m long tubular furnace, and the temperature at the center thereof was 950°C. Diameter 2 for the board
Using circular alumina pellets with a diameter of 0 mm and a thickness of 1 mm,
This alumina pellet is coated with silica.

This substrate was placed in the center of a tube furnace, and a ceramic thin film was formed thereon for 2 hours. FIG. 1 shows the relationship between heating temperature at the center of the tube furnace and time.

The produced thin film was a dense sintered film. The thickness of the thin film was measured using BPMA and was found to be 5 μm.

When the conductivity of the thin film was measured using the four-probe method, it was found to be 7.
It was 4.1 mΩ' am at 3 mΩ・0m177°.

Example 2 A thin film was formed in the same manner as in Example 1 except that the substrate was placed at the outlet of the tube furnace.

A thin film was formed on the substrate of a powdery material with little progress in sintering. This thin film was heat treated and sintered under the temperature conditions shown in FIG. The produced thin film was a dense sintered film, and its thickness was 4.5 μm. The conductivity of the thin film was measured to be 7.6 mΩ' am at room temperature and 4.3 mΩ'' am at 77°.

(Effects of the Invention) According to the present invention, a functional ceramic thin film can be obtained with a simple device at low running cost, and even in the case of multi-component ceramics, a ceramic thin film with a uniform composition can be obtained. Further, the present invention does not require a high vacuum system, and therefore the accessory equipment can be small-sized, and functional ceramic thin films for various uses can be obtained.

[Brief explanation of the drawing]

Fig. 1 shows the relationship between heating temperature and time at the center of the tube furnace in Example 1.2, and Fig. 2 shows the relationship between heating temperature and time in the central part of the tube furnace in Example 1.2.
3 shows the relationship between heat treatment temperature and time for the substrate in FIG. Representative Patent Attorney (8107) Kiyotaka Sasaki, -31 Figure 02 Flow Figure 2 2 Power Flow

Claims (1)

[Claims] In a method for producing a ceramic thin film, one or more inorganic metal salts and/or organic metal salts that are soluble in water or an organic solvent are made into a solution of water and/or an organic solvent, and this is dissolved in microdrops in a heated atmosphere. 1. A method for producing a functional ceramic thin film, which comprises dispersing the solute into a thin film and depositing the functional ceramic on a substrate during or immediately after the thermal decomposition process of a solute.