JPH01259162A - Equipment for producing thin film - Google Patents

Abstract

PURPOSE:To form a thin film little in deterioration even in case of the thermally unstable organic material in the title equipment by a vacuum deposition method by heating the material with pulse laser beam and forming the target of a mixture consisting of the material and metallic particles. CONSTITUTION:A target 3 is provided slantingly at 45 deg. to the horizontal plane in a vacuum chamber 1 and a base plate 2 is provided to the upper part thereof. The target 3 is irradiated by the finely throttled laser beams L from the outside of the chamber 1 via a window part 1a provided on the chamber 1 wall body of the left side of the target 3. This target 3 is formed of the mixture of material molecules 31, metal, e.g., fine Co particles 32 and glycerin 33. When the target 3 is irradiated with the laser beam L, these laser beam L are absorbed by the fine Co particles 32 and the temp. is raised locally and rapidly and the material molecules 31 in the vicinity thereof are instantaneously heated and evaporated and condensed on the base plate 2. Therefore deterioration such as reduction of mol.wt. due to the thermal decomposition of the material molecules 31 can be inhibited.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an apparatus for forming a thin film, and particularly to an apparatus suitable for obtaining a thin film of an organic material.

<Prior Art> In recent years, organic materials have attracted attention as semiconductor materials. However, in order to impart semiconducting properties to an organic material, it is necessary to make it an ultra-thin film, and the LB method, CVD method, or PVD method is conventionally known as a method for forming an ultra-thin film of an organic material. (Hiroyuki Susumbe = "Preparation and electrical properties of ultra-thin polymer films" Applied Physics Vol. 56, No. 2 (1987) 146) The LB method uses an alkyl chain CH3 (CH2) at the end of a long hydrophobic molecule such as CH3 (CH2). When molecules with hydrophilic groups such as -COOH, -0H2, -NH2 are dissolved in an organic solvent such as benzene or chloroform, and the solution is gently dropped onto the water surface, the droplets spread at the air-water interface and the solvent is removed. After evaporation, a monomolecular layer remains, and this monomolecular layer is transferred onto a substrate to obtain a monomolecular cumulative film of an organic material, that is, a Langmuir-Prodgett film.

The CVD method, that is, the chemical vapor deposition method, is a method of vaporizing a monomer and exciting it with plasma or light to generate radicals to form a polymer film on a substrate.

The PVD method, or physical vapor deposition method, includes sputtering, vacuum evaporation, etc. Sputtering is a method in which accelerated ion particles are injected into a target to blow away target molecules, and the molecules are attached to a substrate. The vacuum evaporation method is a method for forming a thin film by heating a vapor deposition source in a vacuum atmosphere to evaporate the vapor, and condensing the evaporated particles on a substrate to obtain a thin film.

<Problem to be solved by the invention> By the way, according to the LB method, it is possible to form a monomolecular film,
Moreover, although it is an excellent method that allows for orientation control, it has the disadvantage that the film formation rate is extremely slow and it can only be applied to the formation of thin films of specific organic substances that have hydrophilic groups at the ends of hydrophobic molecules.

Furthermore, the CVD method is basically a method of forming a polymer film through a polymerization reaction, and has the disadvantage that the material is limited to only polymers.

Furthermore, although the sputtering method can be applied to the formation of thin films of various organic materials, it has the disadvantage that the crystallinity of the obtained thin films is extremely poor.

On the other hand, the vacuum evaporation method can be applied to the formation of thin films of a relatively large number of types of organic materials. However, according to this vacuum evaporation method, the material is heated using, for example, a heater, and the heating rate is slow and the material is exposed to high temperature for a long time until it reaches the evaporation temperature. However, when a thermally unstable organic material is used as a vapor deposition source, there remains the problem that deterioration such as a decrease in molecular weight occurs due to thermal decomposition.

The purpose of the present invention is to suppress deterioration such as a decrease in molecular weight due to thermal decomposition as much as possible even when forming a thin film of a thermally unstable organic material by basically adopting a vacuum evaporation method. The object of the present invention is to provide a thin film manufacturing apparatus that can produce a thin film.

<Means for Solving the Problems> The configuration for achieving the above object will be explained with reference to FIGS. 1 and 2 corresponding to the embodiment. This device evaporates by heating and guides the evaporated particles onto the substrate 2 to form a thin film on the substrate 2, and is configured to heat the material 31 by irradiating pulsed laser light, and The laser beam target 3 is characterized in that it is formed of a mixture of at least a material 31 and metal fine particles 32.

<Effect> It is generally known that when an organic material is irradiated with pulsed laser light, neutral molecules evaporate from the material, and if these evaporated molecules are guided onto a substrate and condensed, a thin film of the organic material can be obtained. be able to.

Here, if the target of the pulsed laser beam is formed only from an organic material, the temperature rise due to pulsed laser beam irradiation is not very rapid, and the heating rate of the material is faster than that of heating with a heater, etc., but it is still sufficient. isn't it. Therefore, when the target 3 is formed from a mixture of the organic material 31 and the metal fine particles 32 and the target 3 is irradiated with laser light, the laser light is absorbed by the metal particles 32, causing a local rapid temperature rise. As a result, material 31
is instantly heated and evaporates.

<Example> Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a longitudinal cross-sectional view showing the structure of an embodiment of the present invention, and FIG. 2 is a diagram schematically showing the structure of a target 3 thereof.

A target 3 held by a holder 4 is arranged in a vacuum chamber 1 at an angle of 45° with respect to a horizontal plane, and a substrate 2 is arranged above the target 3 .

There is a window 1 on the wall of the vacuum chamber 1 on the left side of the target 3.
A is provided so that narrowly focused laser light can be irradiated from outside the vacuum chamber 1 to the target 3 inside the vacuum chamber 1 through the window 1a.

Note that a heater 5 is provided above the substrate 2 to maintain the substrate 2 at a predetermined temperature.

As shown in FIG. 2, the target 3 includes material molecules 31,
It is a mixture of cobalt fine particles 32, glycerin 33, etc., and this mixture is made by dissolving the material of the thin film to be formed, such as an organic substance, in an appropriate solvent that is soluble in the material to create a material solution, and then combining the material solution with cobalt. can be created by mixing microparticles and glycerin.

Note that it is desirable that the diameter of the Koharto fine particles be as fine as possible, and for example, those having a diameter of about several hundred particles are used.

With the above configuration, when the target 3 is irradiated with laser light, the laser light is absorbed by the cobalt fine particles 32, thereby causing a local rapid temperature rise. Due to this temperature rise, the material molecules 31 in the vicinity are instantaneously heated and evaporated, and the evaporated molecules reach the substrate 2 and condense. Thereby, a thin film can be obtained on the substrate 2.

Here, since the material molecules 31 are suspended in the glycerin 33, even if the material molecules 31 at the location irradiated with the laser beam evaporate, they are immediately replenished from the surroundings, and the vapor deposition can be continued for a long time.

Note that the metal fine particles are not limited to cobalt, and any metal that easily absorbs laser light can be used. Further, the smaller the diameter, the more convenient it is to increase the uniformity within the mixture and the total surface area.

Furthermore, glycerin as a mixed substance is not necessarily required, and for example, a uniform mixture of powdered material and fine metal particles may be used as the target.

Next, another embodiment will be described with reference to FIG.

In this example, a vacuum chamber 101 is divided by a partition wall 102 into two chambers, a target chamber T and a deposition chamber V, and each chamber is configured to be evacuated individually. Further, a small hole 102a is bored in the partition wall 102, and material molecules evaporated from the target 3 by laser beam irradiation pass through the small hole 102a and pass through the substrate 2 in the vapor deposition chamber V.
reach the top.

Generally, in order to form a thin film while controlling the orientation, a high vacuum of about 10-'' torr is required. If they are placed in the same chamber 1, the degree of vacuum in the chamber 1 can only be about 10-6 torr.Therefore, by configuring the target chamber T as in this example, the degree of vacuum in the target chamber T can only be about 10-6 torr. Although it is not possible, it is possible to maintain the deposition chamber (2) at about 10-1 Otorr.
-6 torr, and the deposition chamber V is maintained at a vacuum level of about 10-'' torr, the evaporated molecules from the target 3 are vigorously ejected from the small hole 102a, and reach the substrate 2 as molecular beams. Therefore, it can be used as a so-called molecular beam epitaxy device.

Next, another embodiment will be described with reference to FIG. 4.

The feature of this example is that the material molecules evaporated from the target 3 are not simply guided onto the substrate 2, but the evaporated material molecules are ionized by being irradiated with ultraviolet rays or electron beams from the side, and the ions are transferred to the next stage. The point is that a so-called ion blating method is adopted, in which a thin film is obtained by accelerating with an accelerating electrode 46 and colliding with the substrate 2.

<Effects of the Invention> As explained above, according to the present invention, since the material is evaporated by irradiating the material with laser light to the material formed of the mixture of the material and the metal fine particles, the material can be Even when forming thin films of thermally unstable and difficult-to-evaporate materials, especially organic materials, which are heated more rapidly than before and evaporated instantly, the molecular weight decreases due to thermal decomposition. This makes it possible to significantly reduce deterioration such as the following, compared to the conventional method, and to obtain a thin film whose molecular weight is almost close to that of the original material.

In addition, since a vacuum evaporation method is basically adopted, there is also the effect that a thin film having a crystal structure almost identical to that of the original material can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal section showing the configuration of an embodiment of the present invention, FIG. 2 is a diagram schematically showing the configuration of the target solenoid 1 to 3, and FIGS. 3 and 4 are configurations of other embodiments of the present invention. FIG. 2...Substrate 3...Target 31...Material molecules 32...Cobalt fine particles L...Laser light patent applicant Representative representative of Shimadzu Corporation
Patent Attorney Nishi 1) New - Same Figure 1 Figure 2

Claims (1)

[Claims] An apparatus for evaporating a material by heating it in a vacuum atmosphere and guiding the evaporated particles onto a substrate to form a thin film on the substrate, the apparatus being configured so that the heating is performed by irradiation with pulsed laser light. A thin film manufacturing apparatus, characterized in that the target of the pulsed laser beam is formed of a mixture of at least the above-mentioned materials and fine metal particles.