JP2568725B2 - Fabrication method of maskless patterned thin film - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel method for producing a thin film with high efficiency and high accuracy.

2. Description of the Related Art Conventionally, high-efficiency film forming methods include coating and coating methods. Among them, electrostatic coating, electrodeposition coating, powder coating and the like are methods developed in recent years.

On the other hand, many methods such as evaporation and sputtering have been developed with high accuracy down to the atomic order.

Also, plasma polymerization, vapor deposition polymerization, reactive sputtering,
There is also a reactive thin film forming method utilizing a chemical reaction such as CVD.

Problems to be Solved by the Invention As described above, methods of coating such as electrostatic coating, electrodeposition coating, and powder coating are highly efficient methods that can be performed in the air. There has been a problem that it cannot be formed uniformly and a separate drying step is required.

On the other hand, methods such as vapor deposition, sputtering, and reactive thin film formation require a vacuum, take time and do not become highly efficient, and are also economically poor and have many problems in terms of 100% effective utilization of raw materials. Was. Further, when a source having a composite composition is used, there is a disadvantage that gasification cannot be performed with the same composition as the source.

Therefore, an object of the present invention is to provide a novel thin film manufacturing method with high efficiency and high accuracy.

Means for Solving the Problems To achieve the above object, the present invention provides a method in which a solution or suspension containing a thin film forming substance or a precursor thereof is sprayed from a nozzle into a space filled with a carrier gas. Atomization is performed by atomization means, the atomized particles are charged by electric means to control the flight direction, and the solvent trapping means reduces the solvent vapor partial pressure in the carrier gas to reduce the amount of solvent in the atomized particles. Provided is a method for producing a maskless patterned thin film which is controlled during flight and deposited on a heated counter electrode target.

Function The thin film manufacturing method of the present invention has the following function.

a) The method does not fly the atoms and molecules from the source by evaporation or ion bombardment in a vacuum, but the method of flying liquid fine particles into the carrier gas by atomizing means.
Therefore, even if the source liquid is a multi-component liquid such as a solution or a dispersion (suspension), unlike the evaporation phenomenon, it is possible to fly fine particles having the same composition as the source, and the dispersoid is a multi-component liquid. Even if it is a complex, it can fly with its composition without breaking or decomposing the complex.

b) Since the air flies by the atomizing means, heat is not necessarily required for the flight, and the thin film forming material flies without any thermal damage.

c) Since it can fly at normal pressure in the carrier gas, an industrially efficient system can be constructed. The atomized fine particles can be charged by the same technology as the ink jet method, and the direction can be easily controlled.

d) Since the atomization particles are charged by electric means to control the flight direction, they collide with the counter electrode target by electrostatic force, so that they have strong adhesion and the thin film on the flight particle target is charged to the same polarity as the flight particles. This is useful for a dielectric thin film because the electrostatic repulsive force preferentially adheres to a pinhole having a small thickness to form a uniform thin film.

The thin film production method of the present invention is characterized in that a solution or suspension containing a thin film forming substance or a precursor thereof is atomized by an atomizing means in a space filled with a carrier gas, and the atomized particles are electrically To control the flight direction, and reduce the solvent vapor partial pressure of the carrier gas by the solvent trapping means to control the amount of solvent in the atomized particles during flight, forming a thin film on the heated counter electrode target. How to

The method for producing a thin film of the present invention is a method carried out in a space at almost normal pressure filled with a carrier gas, so that a continuous apparatus is easy and has high industrial value. The present invention is characterized in that it can be easily applied to polymers and ceramics for which the vapor phase formation method is difficult.

If a polymer solution is used as the source liquid, a pinhole-less uniform polymer thin film can be prepared, and can be used as an excellent dielectric film, insulator film, or passive film.

In addition, if a suspension of inorganic fine particles containing a thin film-forming substance or its precursor is used, a thin film can be formed as in a cluster ion beam method in which clusters are generated from vaporized molecules in a vacuum and ionized, and a cluster ion beam is used. It is possible to fly many kinds of materials more easily than by the method, and a highly efficient thin film production system can be configured.

In the case of the atomized particles in this case, aggregates of cluster particles, also called multi-cluster particles, are formed during flight. This is useful for forming a porous thin film.

In addition, the method of the present invention can use not only a variety of types of solutions or suspensions such as paints as a source but also all types of molecules and particles as a solute or a dispersoid.

In the case of a suspension, a suspension of inorganic ultrafine particles having an average particle diameter of 50 nm or less and a colloidal solution are more suitable because there is no fluctuation in composition such as sedimentation.

As the carrier gas of the present invention, any of nitrogen, oxygen, an inert gas, a reactive gas, and a mixed gas thereof may be used. It is better to select a carrier gas which has a good saturated solvent vapor pressure.

As shown in FIG. 3, the atomized particles 3 that have flown evaporate the solvent or the dispersion medium during the flight, and become a concentrated liquid → mud →
It changes to solid (cluster) -like particles.

Since the flying particles are charged by the charging means, they collide with the heated counter electrode target as ionized clusters to form a thin film.

The size of the particles colliding with the counter electrode target can be controlled by the concentration of the source solution or dispersion, the atomized particle size, the evaporation amount of the solvent during flight, and the like.

In order to efficiently evaporate the solvent and dispersion medium of the atomized particles during flight, it is desirable that the temperature of the flight space be high and the solvent vapor partial pressure be low.

However, not all flying particles can be charged by this charging means, and neutral atomized particles may eventually be mixed as shown in FIG.

When the carrier gas is caused to flow in the same direction as the flight control direction of the atomized particles by the electric field, the direction of the atomized particles is controlled by riding on the carrier gas, and a thin film can be formed without waste of the source material.

The carrier gas that has passed through the solvent trap for reducing the solvent vapor partial pressure is circulated after the temperature and the flow rate are controlled, and the solvent evaporation rate can be controlled by the conditions of the temperature and the flow rate.

As described above, the carrier gas flows in the same direction as the flight control direction of the atomized particles by the electric field, and the direction of the atomized particles can be controlled by placing the atomized particles on the carrier gas.

Further, when the flying particles are a precursor of a thin film, they undergo a chemical reaction (decomposition, oxidation, etc.) on a heated target, and a reaction product forms a thin film.

Therefore, the present invention can also be used as a method for producing a reactive thin film.

In this case, a reactive gas such as oxygen or hydrogen may be appropriately used as the carrier gas.

The thin film in this case is a surface active film, and thus is useful as a catalyst film.

The present invention is also an excellent method for the purpose of forming a resin thin film by flying a thermosetting prepolymer solution by the method of the present invention and thermosetting on a heated target.

The atomization means includes a spray method, an ultrasonic method, an electrostatic method, a heating bubble method, and the like. Among them, an ultrasonic method, an electrostatic method,
The inkjet head by the heating bubble method is most suitable. These ultrasonic waves each liquid in the nozzle of the head,
It is pushed out by a bubble generated by Coulomb force and heating.

As these atomizing means, a multi-head (multi-source) can also be easily produced.

There is also a method of generating a mist like an ultrasonic humidifier using an electrostrictive element made of a ferroelectric substance.

The charging means is a generally known means in the ink jet method or the ion beam method, and includes means such as corona discharge and electron emission by an ultraviolet laser.

As the counter electrode target, an electrode having a polarity opposite to that of the flying particle charge is used.

Since a thin film can be formed under an electric field, the present invention is also useful for producing a ferroelectric thin film in which dipoles are oriented in the same direction.

As a means for reducing the solvent vapor partial pressure of the carrier gas, a trap set at a temperature equal to or lower than the melting point of the solvent is the simplest and most efficient.

The carrier gas passing through the solvent trap is circulated after controlling the temperature and the flow rate, and these conditions affect the solvent evaporation rate of the flying particles.

 The trapped solvent can be used repeatedly.

The thin film of the present invention is useful for various purposes such as an adhesive film, an optical functional film, a superconducting thin film, a memory thin film, and a semiconductor thin film in addition to the above-described dielectric thin film and catalyst film.

Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings.

Example 1 As shown in FIG. 1, an acrylic water-based dispersion paint is atomized into a chamber (space) 11 filled with a nitrogen carrier gas by an ultrasonic ink-jet head 1 having a ceramic electrostrictive element. The particles 3 were charged by passing through the space 2 subjected to corona discharge, and the flight direction was controlled by the acceleration electric fields 8 and 8-1.

A solvent trap means 10 is provided to reduce the solvent vapor partial pressure of the carrier gas, control the amount of the solvent in the atomized particles during flight, and deposit the thin film on the counter electrode target 7 heated to 150 ° C. Was.

The carrier gas 9 passed through the solvent trap was circulated after the temperature and the flow rate were controlled.

The thin film thus obtained has a thickness of 1 μm and a withstand voltage of 51 μm.
It was as high as 06V / cm.

Embodiment 2 FIG. 2 shows the configuration of an apparatus according to another embodiment of the present invention.

This apparatus is a continuous apparatus in which a material is supplied from a liquid source tank 13 and a thin film is formed on a long substrate 16.

The adhesive polyimide varnish was atomized by the electrostatic inkjet head 1 in the chamber 11 filled with the nitrogen carrier gas, and the atomized particles were charged by passing through the corona-discharged space 2 to control the flight direction. .

A solvent trap 10 was provided to reduce the solvent vapor partial pressure of the carrier gas to control the amount of solvent in the atomized particles during flight.

Long A on the counter electrode target 7 heated to 180 ° C
l A thin film was obtained by attaching it on the substrate 16.

This is post-baked in a continuous furnace at 300 ° C,
A strong uniform thin film was obtained.

The carrier gas 9 that has passed through the solvent trap 10 is
The temperature was controlled by 14 and the flow rate was controlled by the gas circulation pump 12 for circulation.

The far-infrared radiation plate at 300 ° C
Was provided, and the atomized particles were radiantly heated.

Example 3 As shown in FIG. 1, an aqueous dispersion of Sn-doped indium oxide was atomized in a chamber 11 filled with a nitrogen carrier gas by an ultrasonic ink-jet head 1 having an electrostrictive element, so that atomized particles 3 were formed. The air was passed through the corona-discharged space 2, charged, and the flying direction was controlled by the acceleration electric fields 8 and 8-1.

A solvent trap means 10 at −20 ° C. is provided to reduce the partial pressure of water vapor of the carrier gas, to control the amount of solvent in the atomized particles during flight, and to set the ceramic on the counter electrode target 7 heated to 200 ° C. The transparent conductive thin film was obtained by attaching to a substrate.

The carrier gas passed through the solvent trap was post-circulated at a controlled temperature and flow rate.

 The temperature of the flight space of the atomized particles was set at 600 ° C.

Example 4 An apparatus of the present invention was constructed as shown in FIG.

This device is a continuous device, and from the liquid source tank 13,
An apparatus for forming a thin film on a long substrate 16 by supplying a solution of a polyphenylene sulfide polymer as a source material was provided.

In a space 11 filled with air, a solution of a porphenylene sulfide-based polymer is atomized by an electrostatic ink jet head 1, and the atomized particles are charged by passing through a space 2 in which corona discharge has occurred, and fly. The direction was controlled.

A solvent trap means 10 was provided to reduce the solvent vapor partial pressure of the carrier gas, thereby controlling the amount of solvent in the atomized particles during flight.

Long A on counter electrode target 7 heated to 150 ° C
l A thin film was obtained by attaching it on the substrate 16.

The air that has passed through the solvent trap 10 is
It was circulated by 12 and a heater 14, and circulated with controlled temperature and flow rate.

The far-infrared radiation plate of 200 ° C
5 was provided to heat the atomized particles.

Using the thin film of pinhole-less polyphenylene sulfide thus obtained as a dielectric, a laminated film captain was obtained with high efficiency.

Advantageous Effects of the Invention As described above, the present invention provides a solution or suspension containing a thin film-forming substance or a precursor thereof in a space filled with a carrier gas, by atomizing by means of atomizing means, and charging the solution or suspension. And controlling the amount of the solvent in the atomized particles during flight, and providing the thin film on a heated counter electrode target.

The thin film manufacturing method of the present invention provides a novel method for manufacturing a thin film with high efficiency and no pinholes, and has a feature that it can be easily applied to polymers and ceramics which are difficult to form by a vapor phase. It is useful for forming a dielectric thin film.

 It is also useful for forming a catalytically active thin film.

Since the method for producing a thin film of the present invention is carried out in a space at almost normal pressure filled with a carrier gas, a continuous apparatus is easy and has high industrial value.

There is also an industrial advantage that the solvent trapped by the solvent trap can be used repeatedly.

The present invention is characterized in that even if the source liquid is a multi-component liquid such as a solution or a dispersion (suspension), fine particles having the same composition as the source can be caused to fly.

Therefore, even if the dispersoid is a multi-component complex, it can fly with its composition without breaking or decomposing the complex.

Further, since the air flies by the atomizing means, heat is not necessarily required for the air, and the thin film forming material flies without any damage.

Since the charged atomized particles collide with the counter electrode target by electrostatic force, the flying particles have a strong adhesion and the thin film on the target is charged to the same polarity as the flying particles. This has the effect of preferentially adhering to thin pinholes and forming a uniform thin film.

When the carrier gas is caused to flow in the same direction as the flight control direction of the atomized particles by the electric field, the direction of the atomized particles is controlled by riding on the carrier gas, and a thin film can be formed without waste of the source material.

In addition, the method for producing a thin film of the present invention is particularly useful for producing a patterned thin film because the nozzle scanning and the direction control of flying particles are possible as in the ink jet recording method. There is a great feature that a thin film can be produced.

 Thus, the present invention is of great industrial value.

[Brief description of the drawings]

1 and 2 are conceptual diagrams showing a method for producing a thin film according to one embodiment of the present invention, and FIG. 3 is a schematic diagram showing an example of a change of the atomized particles during flight of the present invention. 1 ... atomizing means, 2,2-1 ... charging means, 3 ... atomized particles, 4 ... ionized atomized particles, 6 ... accelerating electrode, 7 ...
Counter electrode target, 9: Carrier gas flow, 10: Solvent trap, 11: Chamber, 12: Gas circulation pump,
13: Liquid source tank, 14: Heater, 15: Far infrared radiation plate, 16: Long substrate

Claims (2)

(57) [Claims] A solution or suspension containing a substance for forming a thin film or a precursor thereof is atomized from a nozzle into a space filled with a carrier gas, and the atomized particles are electrically charged. Means to control the flight direction, and reduce the solvent vapor partial pressure in the carrier gas by the solvent trapping means to control the amount of solvent in the atomized particles during flight, and adhere to the heated counter electrode target. A method for producing a maskless patterned thin film. 2. The maskless patterned thin film according to claim 1, wherein the solvent trap means is a trap set at a temperature equal to or lower than the melting point of the solvent, and the carrier gas passing through the solvent trap is circulated. Method.