JP4736034B2 - Functional gradient structure thin film manufacturing equipment - Google Patents

Description

The present invention relates to manufacturing equipment of the functional thin film having a gradient structure.

  It is known that a gradient structure material in which the concentration of functional material molecules dispersed in a polymer changes in the depth direction from the surface of a thin film or member exhibits or improves various functional material properties.

For example, the hole transporting polymer used in polymer organic electroluminescence (EL) devices is arranged so that the electron transporting material has an inclined structure, thereby suppressing the occurrence of carrier traps and improving the EL emission characteristics. (Non-Patent Document 1). In the case of a refractive index distribution type plastic lens formed by dispersing functional material molecules having a refractive index distribution forming function in an optical polymer, it is relatively easy to obtain a multifocal type lens. It is expected to be highly useful as a contact lens for presbyopia (Patent Document 1). Also in the case of a polymer organic solar cell, the n-type functional material (C ₆₀ ) has a gradient structure distribution in the p-type polymer, so that a donor and an acceptor pair are easily formed efficiently, and the photoelectric conversion efficiency of the solar cell is improved. It is known to improve (Non-Patent Document 2). In the case of a plastic optical fiber, it is known that the refractive index distribution type makes it difficult for mode dispersion to occur, increases the transmission band, and exhibits excellent optical transmission characteristics (Patent Documents 2-3). Furthermore, it has been theoretically and experimentally confirmed that the optical transmission characteristics are dramatically improved by precisely controlling the refractive index distribution curve in the depth direction (Patent Documents 3-4).

  For example, several methods are known as methods for forming these conventional gradient structure materials, but a method of thermally diffusing functional material molecules in a polymer by applying heat (Non-Patent Document 1-2), or 2 Most of the methods (Patent Documents 4-5) form a gradient material by heating and then cooling a polymer blend melt in which a polymer of more than one species is mixed with a temperature gradient. However, it is generally difficult to control the concentration distribution in the depth direction with the method of forming the gradient material by applying these heats.

  On the other hand, apart from the method of forming the gradient material by heat as described above and the apparatus therefor, the present applicant and the present inventors have made the following functional thin film manufacturing method having a gradient structure and the method thereof. Manufacturing equipment has been proposed.

That is, for example, by spraying an organic optical material in a solution or dispersion state into a high vacuum container and depositing it on a substrate, heat treatment, and further pressurizing treatment as necessary, at a lower temperature This is a method for forming a high-quality, high-functional organic optical thin film having a fine structure controlled without causing thermal decomposition of the optical material (Patent Document 6). An inorganic or organic material having two or more components is subjected to atmospheric pressure. A thin film manufacturing apparatus for directly depositing on a substrate by spraying into a high-vacuum container through a spray nozzle provided for each component from the state of the solution or dispersion placed on the solvent, the solvent exhausted from the vacuum or The dispersion medium is trapped by generating a low temperature at which these liquids solidify, or by physical adsorption, preventing these liquids from reaching the vacuum evacuation device, and the deposition chamber and vacuum evacuation device. High-quality, high-performance composite optical thin film at a temperature much lower than the decomposition temperature of organic optical materials by using a thin film manufacturing apparatus characterized by having an exhaust trapping device that creates a large pressure difference between them A composite optical thin film composed of an organic optical material having two or more components, and a high-performance thin film in which the concentration of components is arbitrarily changed in the depth direction in the composite optical thin film (Patent Document 7).

Alternatively, an organic optical material is formed by spraying an organic optical material having two or more components in a high-vacuum container from a spray nozzle provided for each component in a solution or dispersion state, and depositing it on a substrate, followed by heat treatment. It is possible to produce high-quality and high-performance composite optical thin films at temperatures much lower than the decomposition temperature of the above, and in composite optical thin films composed of two or more components of organic optical materials, A composite optical thin film with a controlled structure can be manufactured. Further, a composite optical thin film made of an organic optical material having two or more components can be manufactured by arbitrarily changing the concentration of components in the depth direction. (Patent Document 8).
JP 2000-318057 A JP-A-11-109144 JP 2001-91758 A JP-A-11-302397 JP 2004-268568 A JP-A-6-306181 JP-A-7-252670 JP-A-7-252671 Applied Physics Letter, 78, No. 5, 2001, p. 574-576 Applied Physics Letter, 81, 24, 2002, p. 4607-4609 Journal of Lightwave Technology, Vol. 13, No. 7, 1995, p. 1475-1489 Journal of Lightwave Technology, Vol. 15, No. 11, 1997, p. 2095-2100

The present invention was made from the background of the As described above, the object is achieved even more sophisticated equipment for the formation of a functional thin film by the nozzle spray present inventors have proposed Yes. More specifically, the film can be formed at a temperature much lower than the conventional heating method, for example, much lower than the decomposition temperature of the organic functional material. Since a plurality of nozzles are used to spray each of these, it is not always easy to precisely control the concentration change in the depth (thickness) direction of the thin film, and the plane position of the thin film, that is, the plane of the substrate There is a problem that it is difficult to make the gradient of the component concentration in the depth (thickness) direction uniform depending on the position. Therefore, the present invention solves such problems, facilitates precise control of concentration changes in the depth (thickness) direction, and also causes variations and inaccuracies in the depth (thickness) component concentration due to the planar position. eliminating the uniformity, and an object of the invention to provide a manufacturing apparatus of the functional gradient structure film is a precisely controllable high quality.

When a thin film is formed on a substrate by spraying a mixed solution or dispersion of two or more components into a vacuum vessel from a single nozzle, the concentration of at least one component in the solution or dispersion is changed over time. A functionally graded thin film manufacturing apparatus for manufacturing a functionally graded thin film in which the concentration in the depth (thickness) direction of at least one component thin film of the material forming the thin film is changed by changing to A vacuum vessel, a substrate holder and a spray nozzle disposed in the vacuum vessel, and a liquid supply unit for supplying a mixed solution or dispersion of the thin film forming material, the liquid supply unit forming the thin film It is provided with an adjusting mechanism that can change the concentration of at least one component of the material over time, and this adjusting mechanism is characterized in that a plurality of liquid containers containing the thin film forming material are connected by a siphon mechanism. Functional slope Forming a thin film of manufacturing equipment.

  According to the present invention as described above, taking advantage of the characteristics of the nozzle spraying method that enables film formation at a temperature much lower than the decomposition temperature of the organic functional material, for example, the concentration change in the depth (thickness) direction While making precise control easy, it is possible to manufacture a high-quality and highly functional gradient structure thin film by suppressing variation and non-uniformity of the change in the plane of the thin film.

  Embodiments of the present invention will be described below.

  The functionally graded thin film in the present invention has a compositional gradient in which the concentration of at least one of the two or more thin film forming components changes in the depth of the thin film, that is, in the thickness direction. This means that it is possible to develop or improve specific functions such as optical functionality, electronic functionality, biological functionality, and catalytic functionality. Therefore, the components for forming the thin film may be any of two or more of inorganic and organic materials, and those having a thin film formation. For example, typically, an inclined structure film as an optical functional thin film is provided by the present invention.

  For example, a combination of an organic polymer compound and an organic low molecular compound, a combination of an organic polymer compound and a liquid crystal, a combination of two or more organic polymer compounds, a mixture of an organic polymer compound and a low molecular compound, and a polymer The combination with a compound etc. can be mentioned. In these combinations, any kind of individual component can be used as long as it can be dissolved in a volatile solvent or can be dispersed in a dispersion medium. In addition, each component itself may exhibit an optical function alone, or may be a component that is mixed or combined to realize an optical function. If necessary, these individual components may include selenium, tellurium, germanium, silicon, silicon carbide, cadmium sulfide, cadmium selenide, Cd—Zn—Mn—Se—Te—S—O and Ge—IN—. It can be used in a state where semiconductor fine particles such as Al-As-P and metal fine particles such as gold colloid are mixed.

  In any case, an organic polymer compound, an organic low-molecular compound, fine particles of an organic compound, liquid crystal, and the like can be used in a solution or dispersion state.

Hereinafter, the individual components will be illustrated more specifically.
[Organic Polymer Material] Among organic polymer compounds, those having so-called “optical properties and functions” can be used as one component of the composite optical thin film material of the present invention. Specific examples of such organic polymer materials include polystyrene, poly (α-methylstyrene), polyindene, poly (4-methyl-1-pentene), polyvinylpyridine, polyvinyl formal, polyvinyl acetal, polyvinyl butyral, polyacetic acid. Vinyl, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, polyvinyl methyl ether, polyvinyl ethyl ether, polyvinyl benzyl ether, polyvinyl methyl ketone, poly (N-vinyl carbazole), poly (N-vinyl pyrrolidone), methyl polyacrylate, Polyethyl acrylate, polyacrylic acid, polyacrylonitrile, polymethyl methacrylate, polyethyl methacrylate, polybutyl methacrylate, polybenzyl methacrylate, polycyclohexyl methacrylate , Polybenzyl methacrylate, polycyclohexyl methacrylate, polymethacrylic acid, polymethacrylamide, polymethacrylonitrile, polyacetaldehyde, polychloral, polyethylene oxide, polypropylene oxide, polyethylene terephthalate, polybutylene terephthalate, polycarbonates (biosphenol) + Carbonic acid), poly (diethylene glycol bisallyl carbonates), 6-nylon, 6,6-nylon, 12-nylon, 6,12-nylon, polyethyl aspartate, ethyl polyglutamate, polylysine, polybroline, poly (γ -Benzyl-L-glutamate), methylcellulose, ethylcellulose, benzylcellulose, hydroxyethylcellulose, hydroxypropylcellulose Acetylcellulose, cellulose triacetate, cellulose tributyrate, alkyd resin (phthalic anhydride + glycerin), fatty acid modified alkyd resin (fatty acid + phthalic anhydride + glycerin), unsaturated polyester resin (maleic anhydride + phthalic anhydride + propylene glycol) ), Epoxy resins (bisphenols + epichlorohydrin), polyurethane resins, phenol resins, urea resins, melamine resins, xylene resins, toluene resins, guanamine resins, organic polysilanes such as poly (phenylmethylsilane), organic polygermane and These copolymerization / copolycondensates and carbon disulfide, carbon tetrafluoride, ethylbenzene, perfluorobenzene, perfluorocyclohexane, trimethylchlorosilane, etc. There compounds may be mentioned such as a polymer compound obtained by plasma polymerization.

In addition, these organic polymer compounds contain organic dyes or residues of organic low molecular compounds that exhibit optical nonlinear effects as side chains of monomer units, as crosslinking groups, as copolymerization monomer units, or as polymerization initiation terminals. You may do it.
[Organic low-molecular compound] Specific examples of the organic low-molecular compound used as one component of the material of the composite optical thin film of the present invention include urea and its derivatives, m-nitroaniline, 2-methyl-4-nitro-aniline. Benzene derivatives such as 2- (N, N-dimethylamino) -5-nitroacetanilide, N, N′-bis (4-nitrophenyl) methanediamine, biphenyl derivatives such as 4-methoxy-4′-nitrobiphenyl, Stilbene derivatives such as 4-methoxy-4′-nitrostilbene, 4-nitro-3-picoline-N-oxide, (S)-(−)-N- (5-nitro-2-pyridyl) -prolinol, etc. In addition to chalcone derivatives such as pyridine derivatives, 2 ′, 4,4′-trimethoxychalcone, and second-order nonlinear optically active substances such as thienyl chalcone derivatives, Kind of organic dye, and the like can be mentioned organic pigments.
[Liquid Crystal] Specific examples of the liquid crystal used as one component of the material of the composite optical thin film of the present invention include various cholesterol derivatives, 4′-n-butoxybenzylidene-4-cyanoaniline, 4′-n-hexylbenzylidene. 4′-alkoxybenzylidene-4-cyanoanilines such as -4-cyanoaniline, 4′-ethoxybenzylidene-4-n-butylaniline, 4′-methoxybenzylideneaminoazobenzene, 4- (4′-methoxybenzylidene) amino 4'-alkoxybenzylideneanilines such as biphenyl, 4- (4'-methoxybenzylidene) aminostilbene, 4'-cyanobenzylidene-4-n-butoxyaniline, 4'-cyanobenzylidene-4-n-hexyloxyaniline 4′-cyanobenzylidene-4-alkoxyanily such as Carbonates such as 4′-n-butoxycarbonyloxybenzylidene-4-methoxyaniline, p-carboxyphenyl n-amyl carbonate, n-heptyl 4- (4′-ethoxyphenoxycarbonyl) phenyl carbonate, 4-n 4-alkylbenzoic acid 4′-alkoxyphenyl esters such as 4-butylbenzoic acid 4′-ethoxyphenyl, 4-n-butylbenzoic acid 4′-octyloxyphenyl, 4-n-pentylbenzoic acid 4′-hexyloxyphenyl, etc. 4,4′-di-n-amyloxyazoxybenzene, azoxybenzene derivatives such as 4,4′-di-n-nonyloxyazoxybenzene, 4-cyano-4′-n-octylbiphenyl, 4-cyano-4′-n-octylbiphenyl, 4-cyano-4′-n-dodecylbiphenyl, etc. Liquid crystal such as 4-cyano-4′-alkylbiphenyl and (2S, 3S) -3-methyl-2-chloropentanoic acid, 4 ′, 4 ″ -octyloxybiphenyl, 4 ′-(2 Examples include strongly inductive liquid crystals such as 4-methylbutyl) biphenyl-4-carboxylic acid 4-hexyloxyphenyl and 4′-octylbiphenyl-4-carboxylic acid 4- (2-methylbutyl) phenyl.

  For example, organic polymer materials, organic low molecular materials, pigment substances, liquid crystal substances and the like that can be exemplified as described above are combined in the present invention and dissolved in an appropriate solvent, or dissolved in a dispersion medium, Alternatively, it is dispersed in a dispersion medium and sprayed into a high vacuum container. Various types of solvents or dispersion media can be used at this time. For example, these are solvents that dissolve or disperse individual components of the composite optical thin film as described above, have volatility, and are corrosive. Anything can be used as long as it is not.

  Specifically, alcohols such as methanol, ethanol, isopropyl alcohol, n-butanol, amyl alcohol, cyclohexanol, and benzyl alcohol, polyhydric alcohols such as ethylene glycol, diethylene glycol, and glycerin, ethyl acetate, n-butyl acetate, and acetic acid Esters such as amyl and isopropyl acetate, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, ethers such as diethyl ether, dibutyl ether, methoxyethanol, ethoxyethanol, butoxyethanol and carbitol, tetrahydrofuran, 1,4 -Cyclic ethers such as dioxane, dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane, 1,1,2-trichloroethane Halogenated hydrocarbons such as trichlene, aromatic hydrocarbons such as benzene, toluene, xylene, chlorobenzene, o-dichlorobenzene, nitrobenzene, anisole, α-chloronaphthalene, n-pentane, n-hexane, n-heptane, Aliphatic hydrocarbons such as cyclohexane, amides such as N, N-dimethylformamide, N, N-dimethylacetamide, hexamethylphosphoric triamide, cyclic amides such as N-methylpyrrolidone, tetramethylurea, 1, Urea derivatives such as 3-dimethyl-2-imidazolidinone, sulfoxides such as dimethyl sulfoxide, carbonates such as ethylene carbonate and propylene carbonate, nitriles such as acetonitrile, propionitrile, benzonitrile, pyridine, quinoline, etc. of In addition to nitrogen-containing heterocyclic compounds, amines such as triethylamine, triethanolamine, diethylaminoalcohol, and aniline, solvents such as water, nitromethane, carbon disulfide, and sulfolane can be used.

  And as above-mentioned, the method of this invention sprays all the components which form the thin film of two or more components from a single nozzle, and the density | concentration of at least one component is the depth (thickness) direction of a thin film. The method is characterized by providing a changing gradient, but in carrying out this method, the method and apparatus for forming a thin film by spraying already proposed by the present inventors are technically based. it can.

The manufacturing apparatus of the present invention can show, for example, the one illustrated in FIG. 1A as one basic form, and a solution or dispersion of a thin film forming material having two or more components can be used, for example, at a pressure of 1 × 10 ⁻⁴ Pa. As a means for spraying into the following vacuum, a single spray nozzle (1) and an opening / closing mechanism part (2) of the spray nozzle are disposed in the vacuum container (3), and further in this vacuum container (3) A vacuum pump (4) is provided for quickly exhausting vapors of the volatilized solvent or the like and maintaining the pressure in the vacuum vessel (3) at 1 × 10 ⁻⁴ Pa or less.

Further, in the manufacturing apparatus of the present invention, the pressure measuring device (5) installed in the vacuum vessel (3), the vapor of the solvent volatilized in the vacuum vessel (3) reaches the vacuum pump (4). And a cold trap (6) for preventing water, a shutter (7) for shielding between the spray nozzle (1) and the substrate (15), a substrate heating device (8), and a substrate temperature measuring device (9). These devices make it possible to form a functionally graded thin film on the surface of the substrate (15) in the vacuum vessel (3).

  The apparatus is preferably provided with a surface heating apparatus (10) as necessary.

The vacuum pump (4) evacuates the vacuum vessel (3) from atmospheric pressure to high vacuum, and more preferably as quickly as possible to a pressure of 1 × 10 ⁻⁴ Pa or less, and volatilizes in the vacuum vessel to cold. Any gas component such as a solvent that could not be captured by the trap (6) can be quickly exhausted, and the pressure can be kept at 1 × 10 ⁻⁴ Pa or less in the vacuum vessel (3). Can be used. Specifically, a combination of a turbo molecular pump and a rotary pump, or a combination of an oil diffusion pump and a rotary pump can be used.

About a pressure measuring device (5), generally well-known arbitrary things can be used if a pressure below ^{1x10 <-2} > Pa can be measured correctly. For example, an ionization gauge such as a Bayard-Alpert type can be used.

  The vacuum vessel (3) preferably has a configuration in which the device forming parts are arranged so that the volume of the vacuum system is minimized, and the material is preferably high vacuum specification aluminum or stainless steel. The substrate heating device (8) preferably includes a mechanism for controlling the substrate temperature to a predetermined value. Either a type in which the heater portion is placed in a vacuum system or a method in which heating is performed from outside the vacuum system may be used. Any one of them can be used depending on the form).

  The substrate temperature measuring device (9) measures the temperature of the substrate (15), and any device can be used as long as it operates by placing a temperature measuring unit such as a thermocouple under high vacuum.

  The surface heating device (10) may be appropriate, and the cold trap (6) is optional as long as it reliably captures vapors such as solvent volatilized in the high-vacuum container and does not hinder exhaustion. Can be used.

  1A is also equipped with a substrate holder (14) that supports the substrate (15), an opening / closing mechanism (12), a cold trap (13), and the like.

  Various forms may be considered as a nozzle for spraying a thin film forming material of two or more components from a single nozzle to form a gradient structure thin film and the spraying mechanism.

For example, a siphon structured solution or dispersion concentration adjusting mechanism may be employed as in Example 1 described later, or an adjusting mechanism using a pump may be employed as in Reference Examples 2 and 3 . In any case, the concentration of at least one component can be changed with the lapse of time of spraying. As for the nozzle itself, the simple pinhole type may have various structures such as those already proposed by the inventors.

  In the present invention, a single nozzle as described above, that is, a nozzle for spraying all mixed solutions or dispersions of thin film forming materials having two or more components, and at least one component as the spraying time elapses. Inclined structure is formed using a nozzle equipped with an adjustment mechanism so that the concentration of the liquid is controlled, and as a process before and after that, by forming a thin film by conventional nozzle spraying, an inseparable multilayer thin film is formed as a whole. It may be formed.

In the present invention, a thin film, that is, a gradient structure film or a multilayer film including the thin film may be subjected to heat treatment, or pressure treatment for molding may be performed. Known processes and means may be employed.

  Needless to say, the type of the substrate (15) is not particularly limited. Depending on the composition and application of the thin film to be formed, substrates made of various inorganic and metal organic materials such as glass, quartz and silicon are used.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not limited to a following example, unless the summary is exceeded.
<Example 1>
The organic functional thin film was manufactured using the apparatus which illustrated the formation in FIG. That is, the opening / closing mechanism (16) is opened, the inside of the vacuum vessel (3) is evacuated by the vacuum evacuation devices (17), (18), (turbo molecular pump and oil rotary pump), and then the pressure in the vessel (3) is increased. The pressure was measured with a pressure measuring device (5), and it was confirmed that the pressure was 1 × 10 ⁻⁴ Pa or less.

Copper (II) as an organic functional material
In order to disperse 2,9,16,23-tetra-tert-butyl-29H, 31H-phthalocyanine [(t-Bu) ₄ CuPc] in a polymer, for example, polycarbonate (PC), (t-Bu) ₄ CuPc (T-Bu) ₄ CuPc at a concentration of 0.01 wt% and PC at a concentration of 0.1 wt% in chloroform, respectively, in a suitable solvent that dissolves both PC and PC, for example, solution A (21 The solution A was filled in the container A (19), and the fuser A (19) was placed in the liquid reservoir (100). On the other hand, (t-Bu) ₄ CuPc is not contained, PC is dissolved in chloroform at a concentration of 0.1 wt% to prepare solution B (22), and solution B (20) is filled into container B (20). The container B (20) was placed in the liquid reservoir (100).

The container A (19) and the container B (20) were connected by a siphon (23), and the container B (20) was connected to a high performance liquid chromatograph (HPLC) pump (11). In order to always make the concentration of the solution (the solution B or a mixture of the solution A and the solution B) in the container B (20) constant, the container B (20) was placed in the ultrasonic cleaner (24). After closing the opening / closing mechanism (16), the opening / closing mechanism (12) is opened, the inside of the vacuum vessel (3) is evacuated by the vacuum exhaust device (4) (oil rotary pump), and then the opening / closing mechanism (2) is opened. Then, the solution B in the container B (20) was sprayed at 1 ml / min from the pinhole spray nozzle (1) having a pore diameter of 20 μm into the vacuum container (3). Since the solution in the container A (19) moved to the container B (20) through the siphon (23) as the solution volume in the container B (20) decreased due to the spraying (siphon principle), the spray nozzle (1 ), The (t-Bu) ₄ CuPc concentration in the solution sprayed gradually decreased with the lapse of spraying time. During spraying, a glass substrate (15) of 5 cm × 4 cm × 0.2 mm was heated to 150 ° C. using a substrate heating device (8), a surface heating device (10) and a substrate temperature measuring device (9). By this heating, volatile components such as a solvent were removed from the surface of the substrate (15) and captured by a cold trap (6) installed in the vacuum vessel (3). Therefore, (t-Bu) ₄ CuPc-containing PC mist that hardly contains a solvent such as chloroform reached the surface of the substrate (15), and the reached mist was heated equally to the glass transition temperature (T _g ) of PC. The (t-Bu) ₄ CuPc-containing PC thin film was finally formed on the substrate (15) by dissolving on the substrate (15) and continuing spraying.

The film thickness was controlled by the spraying time. For example, a 5-micron (t-Bu) ₄ CuPc / PC composite thin film could be formed by spraying for 10 minutes.

Further, when depositing a thin film having a thickness of 20 microns or more, the substrate was heated by a surface heating device (10) using infrared rays or the like, and the volatile components reaching the substrate surface were quickly removed. Deposited _{(t-Bu) 4 CuPc /} PC composite thin film of _(t-Bu) 4 CuPc
In order to observe the concentration distribution in the depth direction of copper atoms contained in the film, the central part of the thin film (5 cm × 4 cm) is cut into a size of 2 mm × 5 mm with a knife, and then this cross section is sampled by a transmission electron microscope (TEM) sample preparation device A thin piece having a thickness of 150 nanometers was processed by cutting with an ultramicrotome which is a kind of the above, and the thin piece was placed on a molybdenum TEM grid. First, the flakes were observed by wide-angle scattering dark field-scanning transmission electron microscopy (HAADF-STEM). The results are shown in FIG. The bright portion in FIG. 2 indicates a portion containing heavy elements. It turns out that it changes gradually from a bright part to a dark part from the right end (thin film back surface) of a thin film toward the left end (thin film surface). When the EDX spectrum of the bright part and the dark part was measured with an energy dispersive X-ray fluorescence spectrometer (EDX), the peak derived from the copper Kα ray was detected from the bright part, but the peak derived from copper was completely absent from the dark part. Could not be detected. In addition, no peaks derived from heavy elements other than copper were observed except for molybdenum derived from the molybdenum grid. From the above results, the bright part is derived from the copper atom contained in (t-Bu) ₄ CuPc, and therefore the (t-Bu) ₄ CuPc concentration in PC gradually changes in the depth direction of the film. Was found to be formed. The HAADF-STEM images of the right end, the left end, the upper end, and the lower end of the plane of the thin film (15) in the arrangement state of FIG. 1 are exactly the same as those in FIG. 2, and the film thickness of the thin film and (t-Bu) ₄ CuPc It was confirmed that the concentration distribution in the depth direction was constant everywhere in the top, bottom, left and right of the thin film.

  Next, when line analysis of copper atoms using EDX was performed on a straight line connecting the left end (thin film surface) to the right end (thin film back surface) in FIG. 2 and the change in copper atom concentration from the thin film surface to the back surface was determined, It was confirmed that a structure in which the copper atom concentration changes in proportion to the depth from the surface of the thin film can be formed.

When the thin film is formed by the apparatus shown in FIG. 1, the initial volumes of the solution A and the solution B are sufficiently large with respect to the spray rate of the solution, the liquid surfaces of the solution A and the solution B are always equal, and the spray rate is always constant. Is assumed, the time change of the (t-Bu) ₄ CuPc concentration in the spray solution (mixture of solution A and solution B) is approximated by the following equation.

dC _B (t) / dt = (C _A0 −C _B (t)) v / (2V ₀ −vt)
Here, t is the spraying time, C _A0 is the initial concentration (constant) of (t-Bu) ₄ CuPc in solution A, and C _B (t) is the solution in solution B (solution A and solution B after t seconds). (T-Bu) ₄ CuPc concentration in the mixture) (ie (t-Bu) ₄ CuPc concentration in the spray solution), v is the spray rate (constant) of the solution, V ₀ is the initial volume of solution A and solution B (Constant).

Therefore, when the initial concentration of (t-Bu) ₄ CuPc in the solution B is C _B0 (constant), the container B
The time dependency of the concentration of the solution is as follows.

C _B (t) = (C _A0 −C _B0 ) vt / 2V ₀ + C _B0
Since the spray rate v is constant and the polymer concentrations in the solution A and the solution B are also constant, the film thickness of the thin film increases in proportion to time. Therefore, it can be seen that the (t-Bu) ₄ CuPc concentration in the depth direction from the front surface to the back surface, that is, the copper atom concentration varies in proportion to the depth from the thin film surface, which explains the above result. ing. In this way, by using the principle of siphon, an inclined structure film in which the (t-Bu) ₄ CuPc concentration changes in proportion to the depth from the film surface with a very simple apparatus is formed with good controllability. I was able to.
< Reference Example 1 >
Also, the solution A is sprayed under the same conditions as described above with the same apparatus as in FIG. 1 except that the siphon (23) does not exist, and then the solution A is sprayed by exchanging the container A and the container B. A thin film having a thickness of 30 microns was formed. HAADF-STEM observation and EDX spectrum were measured in the same manner as described above. As a result, when, as shown in HAADF-STEM image in FIG. 3, does not exist at all _(t-Bu) 4 CuPc the upper right of the thin film, the lower left _(t-Bu) 4 CuPc is micrometer level A uniform two-layer structure film could be formed. The HAADF-STEM images of the right edge, left edge, upper edge, and lower edge of the formed thin film are exactly the same as those in FIG. 3, and it can be confirmed that the thickness of each of the two thin films is constant at the upper, lower, left and right positions of the thin film. It was. Thus, it was also confirmed that the gradient structure film and the two-layer structure film can be easily formed separately.
[Comparative Example 1]
The materials and concentrations of Solution A and Solution B were the same as in Example 1.

Using the apparatus disclosed in Patent Documents 7 and 8, Solution A and Solution B were simultaneously sprayed from separate spray nozzles using two spray nozzles attached thereto. In accordance with the description in the patent document, spraying was performed with the spraying speeds being linked to each other. That is, the spray rate of solution A at the start of spraying is started at 100 μl / min by adjusting the spray rate of solution B to zero, and the spray rate of solution A is decreased in proportion to the time, while the spray rate of solution B , And the sum of both spray rates was always kept at 100 μl / min, after 50 minutes to zero for solution A and 100 μl / min for solution B. The substrate heating temperature was set to 150 ° C. as in Example 1. An inclined structure film having a thickness of 35 μm and an area of 5 cm × 4 cm was formed. As in Example 1, when the center portion, the top, bottom, left and right portions of the thin film were cut out and the HAADF-STEM observation and the EDX spectrum were measured, the depth from the thin film surface on the straight line connecting the thin film surface to the thin film back surface was measured. It was confirmed that a structure in which the copper atom concentration varies proportionally can be formed. On the other hand, the concentration distribution on the left and right of the thin film plane is different from the concentration distribution in the depth direction of copper atoms at the center and upper and lower portions of the thin film, and the total copper content is larger on the right side near the nozzle sprayed with the solution A. It was. This is considered to be caused by such a difference in concentration distribution and total copper content because two spray nozzles were used.
< Reference Example 2 >
An organic functional thin film was produced in the same manner as in Example 1 except that the apparatus illustrated in FIG. 4 was used for the experimental conditions (dye concentration, substrate heating temperature, etc.) other than the solution spraying method.

In the apparatus in this case, the solution A (21) is filled into the container A (19), the solution B (22) is filled into the container B (20), and the container A (19) and the container B (20) are respectively filled with the HPLC pump. (11) and an HPLC pump (25). The outlets of the HPLC pump (11) and the HPLC pump (25) were connected to the spray nozzle (1), and the solution A and the solution B were sprayed from the spray nozzle (1) into the vacuum vessel (3). The flow rate of the HPLC pump (11) was changed in proportion to time from 0 ml / min to 100 μl / min during 100 minutes from the start of spraying, and the flow rate of the HPLC pump (25) was fixed at 100 μl / min. Other conditions such as the substrate temperature were set in the same manner as in Example 1. In order to obtain the copper atom depth direction concentration distribution of the central portion of the (t-Bu) ₄ CuPc-containing PC thin film thus formed, HAADF-STEM observation and EDX spectrum were measured in the same manner as in Example 1. It was confirmed that gradually increased from the right end (thin film back surface) to the left end (thin film surface) of the thin film. The HAADF-STEM images of the right end, the left end, the upper end, and the lower end of the plane of the thin film (15) in the arrangement state of FIG. 4 formed are exactly the same, and the film thickness of the thin film and the depth direction of (t-Bu) ₄ CuPc It was confirmed that the concentration distribution was constant everywhere up, down, left and right on the thin film plane.

When a thin film is formed in the apparatus shown in FIG. 4, the concentration of polymer to solutions A and B is constant, further _(t-Bu) for PC in solution A 4 CuPc concentration _{C A} constant, solution B Assuming that the (t-Bu) ₄ CuPc concentration with respect to the PC is constant and zero, the spray rate of the solution A increases in proportion to the time t, v _A t, and the spray rate of the solution B is constant and v _B. The (t-Bu) ₄ CuPc concentration C (t) in the spray solution at t (that is, the mixture of the solution A and the solution B) is expressed by the following equation.

_{C (t) = C A v} A t / (v A t + v B)
Accordingly, the film thickness h after the elapse of time t is as follows.

_{dh (t) = D (v} A t + v B) dt
Here, D is a constant. Solving this,
^{_{h (t) = D (v}} A t 2/2 + v B t)
Therefore,

When this is graphed, it is as shown in FIG. 5, which almost coincides with the experimental results.
In addition, the flow rate of the HPLC pump (11) was changed in proportion to the time from 0 ml / min to 100 μl / min during 100 minutes from the start of spraying under the same experimental conditions as described above with the apparatus shown in FIG. When the thin film is formed by changing the flow rate of the pump (25) from 100 μl / min to 0 ml / min in proportion to the time, the (t-Bu) 4CuPc concentration changes in proportion to the distance from the film back surface. Could be formed.

As described above, by using the apparatus illustrated in FIG. 4, the (t-Bu) ₄ CuPc concentration changes as shown in FIG. 5 or in proportion to the distance depending on the distance from the film back surface. A film could be formed.
< Reference Example 3 >
An organic functional thin film was produced in the same manner as in Example 1 except that the apparatus illustrated in FIG. 6 was used for the experimental conditions (pigment concentration, substrate heating temperature, etc.) other than the solution spraying method.

In the apparatus in this case, the solution A (21) is filled into the container A (19), the solution B (22) is filled into the container B (20), and the container A (19) and the container B (20) are respectively filled with the HPLC pump. The solvent switching unit (30) connected to (11) was connected. The HPLC pump (11) was connected to the spray nozzle (1), and the solution A and the solution B were sprayed from the spray nozzle (1) into the vacuum vessel (3). Start by adjusting the composition ratio of solution A to 100% and the composition ratio of solution B to zero in the mixed solution of solution A and solution B at the start of spraying, and reduce the composition ratio of solution A in proportion to the time. The composition ratio of solution B was increased, and after 100 minutes, the composition ratio was zero for solution A and 100% for solution B. The spraying time was fixed at 100 μl / min. Other conditions such as the substrate temperature were set in the same manner as in Example 1. In order to obtain the copper atom depth direction concentration distribution of the central portion of the (t-Bu) ₄ CuPc-containing PC thin film thus formed, HAADF-STEM observation and EDX spectrum were measured in the same manner as in Example 1. From the right end (thin film back surface) of the thin film to the left end (thin film surface), it was confirmed that it decreased in proportion to the distance from the back surface. The HAADF-STEM images of the right end, left end, upper end, and lower end of the plane of the thin film (15) in the arrangement state of FIG. 6 formed are exactly the same, and the film thickness of the thin film and the depth direction of (t-Bu) ₄ CuPc It was confirmed that the concentration distribution was constant everywhere up, down, left and right on the thin film plane.

Further, the apparatus shown in FIG. 6 was started by adjusting the composition ratio of solution A to 100% and the composition ratio of solution B to zero in the mixed solution of solution A and solution B at the start of spraying under the same experimental conditions as above. The composition ratio of solution A is decreased exponentially with respect to time, while the composition ratio of solution B is exponentially increased. After 100 minutes, composition ratio is zero for solution A, and for solution B. 100%. When the spraying time was fixed at 100 μl / min and a thin film was formed, (t-Bu) ₄ Cu
An inclined structure film in which the Pc concentration decreases exponentially with respect to the distance from the film back surface could be formed.

As described above, by using the apparatus illustrated in FIG. 6, an inclined structure film in which the (t-Bu) ₄ CuPc concentration increases in proportion to the distance from the film back surface or exponentially with respect to the distance. Could be formed.

It is a formation figure which illustrated apparatus formation of this invention with a siphon system. It is a HAADF-STEM image of the cross section of the (t-Bu) ₄ CuPc-containing PC thin film having an inclined structure in Example 1. In Reference Example 1, a had a two-layer structure _{(t-Bu) 4 HAADF-} STEM image of CuPc-containing PC thin cross-section. It is a formation figure which illustrated the apparatus formation of this invention which has two HPLC pumps in the reference example 2 . In thin film formed by using the method in Reference Example 2 is a diagram showing a change in distance over the (t-Bu) ₄ CuPc surface of a thin film back surface concentrations. It is the formation figure which illustrated the apparatus formation of this invention which has the HPLC pump which attached the solvent switching unit in the reference example 3. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Control nozzle part 2 Opening / closing mechanism part 3 Vacuum container 4 Evacuation apparatus 5 Pressure measuring apparatus 6 Cold trap 7 Shutter 8 Substrate heating apparatus 9 Substrate temperature measuring apparatus 10 Surface heating apparatus 11 HPLC pump 12 Opening / closing mechanism part 13 Cold trap 14 Substrate holder 15 Substrate 16 Opening / closing mechanism 17 Vacuum exhaust device 18 Vacuum exhaust device 19 Container A
20 Container B
21 Solution A
22 Solution B
23 Siphon 24 Ultrasonic cleaner 25 HPLC pump 30 Solvent switching unit 100 Liquid reservoir

Claims (1)

When a thin film is formed on a substrate by spraying a mixed solution or dispersion of two or more components into a vacuum vessel from a single nozzle, the concentration of at least one component in the solution or dispersion is changed over time. A functionally graded thin film manufacturing apparatus for manufacturing a functionally graded thin film in which the concentration in the depth (thickness) direction of at least one component thin film of the material forming the thin film is changed by changing to A vacuum vessel, a substrate holder and a spray nozzle disposed in the vacuum vessel, and a liquid supply unit for supplying a mixed solution or dispersion of the thin film forming material, the liquid supply unit forming the thin film It is provided with an adjusting mechanism that can change the concentration of at least one component of the material over time, and this adjusting mechanism is characterized in that a plurality of liquid containers containing the thin film forming material are connected by a siphon mechanism. Functional slope Forming a thin film of manufacturing equipment.