JPH0713178A - Production of multilayer film containing transparent conductive film - Google Patents

Abstract

PURPOSE:To laminate a functional film on a transparent conductive film without changing its conductivity by applying a soln. containing an org, indium metal compd. on a transparent substrate by coating or printing, and thermally decomposing the soln. to form a transparent conductive film containing indium oxide. CONSTITUTION:This multilayer is obtd. by the following method. A soln. prepared by dissolving (C8H17COO)3In, (C8H17COO)2Sn in dodecane is applied on a quartz substrate 1 with a wire bar, dried, and baked to form a In2O3/SnO2 film 2 as a transparent conductive film. Then soln. of Si resinate and n-butanol is applied with a wire bar on the transparent conductive film 2, dried and baked to form a SiO2 film 3. Further, soln. of (C8H17COO)2Zn, Si resinate, (C8H17COO)2 Mn, terpineol is applied with a wire bar, dried and baked to obtain a phosphor layer of Zn2SiO4:Mn film 4 on the SiO2 film 3. Further, a SiO2 film 5 is formed on the phosphor layer 4, and an electrode layer 6 is formed by vapor deposition of Al on the SiO2 film 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a multilayer film including a transparent conductor film.

[0002]

2. Description of the Related Art Transparent conductor films are used, for example, in liquid crystal displays (LCD) and plasma display panels (PD).
P), electroluminescence display (EL
D), a display such as an electrochromic display, or a window material such as a solar cell. A multilayer film including a transparent conductor film is used for various purposes, for example, by changing various oxide films as a functional film laminated on the transparent conductor film. For example, by using an oxide film as a phosphor film, an electroluminescence display, an electrochromic film, an electrochromic display, an electrochromic light control device, or a resistor, a ferroelectric substance, or a magnetic substance Applications are possible. Further, the functional film laminated on the transparent conductor film is not limited to the oxide film, and various films have been considered depending on the purpose.

Conventionally, as a method for producing a transparent conductor film,
For example, as disclosed in “Surface Technology vol.43, No.2, p.2 (1992)” and the like, a sputtering method and a vapor deposition method are generally well known. Further, as disclosed in Japanese Patent Publication No. 54-28396, there is also known a method for producing an indium oxide coating film by a coating pyrolysis method.

[0004]

The properties required of the transparent conductor film are not only transparency (high visible light transmittance) and conductivity but also environmental stability, particularly stability to heat. . This is because, when a functional film is formed on the transparent conductor film after it is formed, it may be exposed to high temperature, and after the functional film is formed, heat treatment is performed to improve crystallinity and reduce defects. This is because it needs to be applied.

However, conventionally, indium oxide / tin oxide (IT
O) is usually formed as a polycrystal, but when such a transparent conductor film is subjected to heat treatment when forming a functional film to be laminated thereon, for example, “Surface Technology vol.
o.12, p.98 (1992) ", etc., it is known that the heat treatment changes the conductivity of the transparent conductor, that is, the subsequent heating increases the resistivity. Has been.

On the other hand, the aforementioned Japanese Patent Publication No. 54-28396 discloses only the formation of an indium oxide film by a coating pyrolysis method, and another film is formed on the formed indium oxide film. Nothing is said about stacking.

An object of the present invention is to provide a method capable of laminating a functional film on a transparent conductor film without changing its conductivity in view of the problems of the prior art. .

[0008]

A method for producing a multilayer film including a transparent conductor film according to the present invention comprises applying a solution containing an organic indium compound onto a transparent substrate and thermally decomposing the transparent indium oxide transparent conductor film. And then forming a functional film directly or indirectly on the transparent conductor film by a process including a heating process.

[0009]

The transparent conductor film formed by means of applying a solution containing an organic indium compound and thermal decomposition is a transparent conductor film even if a functional film is formed on the transparent conductor film and then heat treatment is performed. Since it does not lower its conductivity, it can be used for producing a multilayer film requiring a transparent conductor film.

[0010]

The present invention will now be described in more detail with reference to the accompanying drawings, which is a specific example for carrying out the method for producing a multilayer film including a transparent conductor film according to the present invention.

First, before explaining the specific example,
Examples of materials and the like for each constituent part that can be used to carry out the method for producing a multilayer film of the present invention will be described. Examples of the transparent substrate used in the present invention include heat resistant transparent substrates such as quartz, non-alkali glass and borosilicate glass. The thickness of the transparent substrate is not particularly limited. The organic indium compound used for forming the transparent conductor film includes (R ₁ COO) ₃ In [wherein R ₁ is 4 carbon atoms
To 16 alkyl groups], (CH ₃ COCHCOC
H _{3) 3} In, and the like.

In addition to the organic indium metal compound, an organic tin compound may be added to the solution containing the organic indium metal compound formed on the transparent conductor film in order to improve the conductivity. Examples of the organic tin compound include (R ₂ C
OO) ₂ Sn [wherein R ₂ represents an alkyl group having 4 to 16 carbon atoms], (CH ₃ COCHCOCH ₃ ) ₂ Sn
Etc. The addition amount of the organic tin compound is preferably 0 to 40% in terms of tin / indium molar ratio. If the molar ratio of tin is higher than this, the conductivity becomes low.

As the solvent of the organic indium compound-containing solution, aliphatic hydrocarbons such as octane, decane, dodecane and tridecane are selected from the viewpoint of wettability to a transparent substrate such as quartz, non-alkali glass and borosilicate glass. Although it is particularly desirable, any solvent having solubility for the organic indium compound, such as aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as methylene chloride, may be used. The concentration of the solution is preferably in the range of solid content ratio of 5 to 50%.

As an additive, the solution is thickened,
Cellulose derivatives such as ethyl cellulose and nitrocellulose may be added to improve the adhesion to the substrate, or unsaturated carboxylic acids such as linoleic acid and linolenic acid may be added to improve the wettability with the substrate. The addition amount is preferably in the range of 0 to 50%.

A multi-layer film formed on the transparent conductor film
In the case of a phosphor film, this is a solution containing an organometallic compound.
When formed by application of liquid or thermal decomposition, Ca, W,
Ba, Si, Zn, Cd, P, Sr, Mg, As, G
e, Y, V, Ga, Pb, Mn, Ti, Sn, Eu, E
Including r, Sm, Tm, Tb, Al, Nd, Ce, Bi, etc.
An organometallic compound having is used. Also other fluorescence
Formed by heat treatment after stacking the film that will become the body film
Sometimes, especially as a compound of II-VI group, MgS, Ca
S, SrS, ZnS, CdS and other sulfides, ZnO, Zn
₂SiO_Four: Mn ²⁺, CaWO_Four, Y₂O₃: Eu³⁺,
BaMg₂Al₁₆O₂₇: Eu²⁺, YAlO ₃: Er³⁺,
Ga₂O₂S: Tb³⁺Oxides such as BaF₂, Ca
F₂, MgF₂: Mn²⁺Such as fluoride, LaPO_Four: C
e³⁺, Tb³⁺, (Ba, Ca, Mg)₃(PO_Four)₃C
l: Eu²⁺Such as phosphoric acid, halophosphorylated compounds, etc.
Be done.

When the electrochromic film is formed by applying an organometallic compound-containing solution and thermally decomposing it, an organometallic compound containing V, W, Ni, Mo, Ti or the like is used. In addition, when the film to be the other electrochromic film is formed by heat treatment after lamination, in particular, V ₂ O ₅ , WO ₃ , NiO, Mo
O ₂ or the like is used.

As for producing the magnetic film,
Fe, Co, Ba, Mn, Ni, Zn, Y, Mg, G
An organometallic compound containing d, Sr, V, etc. is used.

As a material for forming a ferroelectric film, Ti, Ba, Pb, La, Zr, Li, Ge and Z are used.
n, Sr, Mg, Ca, Ta, Nb, V, W, Mn, C
An organometallic compound containing u, Ga, Al or the like is used.

When the insulating film is formed by applying a solution containing an organometallic compound and thermally decomposing it, S is formed.
i, Bi, Pb, Sn, Al, Ti, B, Zr, Ca,
An organometallic compound containing Ba, Ta or the like is used.
In addition, when a film to be another insulating film is formed by heat treatment after laminating, especially SiO ₂ , Y
₂ O ₃ , Al ₂ O ₃ , Ta ₂ O ₅ , PbTiO ₃ , Ba
_{Ta 2 O 6, SrTiO 3,} Si 3 N 4 and the like.

As the solvent for the solution containing the organometallic compound,
Any solvent may be used as long as it has solubility for the organometallic compound. For example, octane, decane, tridecane and other aliphatic hydrocarbons, toluene, xylene and other aromatic hydrocarbons, methylene chloride, chlorobenzene and other halogenated hydrocarbons, ethanol, butanol, terpionel, ethylene glycol and other alcohols, acetone , Methyl ethyl ketone,
Examples thereof include ketones such as cyclohexanone, ethers such as diethyl ether and tetrahydrofuran, and esters such as ethyl acetate and benzyl acetate.

The concentration of the solution is preferably such that the solid content ratio is 5 to 50%. When a commercially available metal resinate is used, it may be diluted with the above solvent, but the metal resinate may be used as it is.

As an additive, the solution is thickened,
Cellulose derivatives such as ethyl cellulose and nitrocellulose may be added to improve the adhesion to the substrate, or unsaturated carboxylic acids such as linoleic acid and linolenic acid may be added to improve the wettability with the substrate. The addition amount is preferably in the range of 0 to 50%.

Examples of the coating method of the organic indium compound-containing solution and the other organic metal compound-containing solution include bar coating, spin coating, spray coating, screen printing and dip coating.

The method of pyrolyzing the coating film of the solution containing the organic indium compound is carried out in an electric furnace or the like at a temperature of 400 to 1500 ° C. for 30 minutes to 10 hours. When the baking temperature is low, the thermal decomposition of the organic indium compound is insufficient and the conductivity is low, and when the baking temperature is high, the substrate component penetrates into the indium oxide film and the conductivity is lowered. The firing time may be 10 hours or longer, but it is not particularly required to be 10 hours or longer. Examples of the firing atmosphere include air, nitrogen, an oxygen flow, nitrogen, an oxygen substitution atmosphere, and a reduced pressure atmosphere. The film thickness of the fired oxide is preferably 0.05 to 10 μm. Than this,
If it is thin, the conductivity is low, and if it is too thick, the transparency deteriorates. Further, in order to increase the film thickness, the application of the solution containing an organic indium compound and the thermal decomposition may be repeated.

The other method of pyrolyzing the coating film of the solution containing the organometallic compound is 400 to 1500 ° C. in an electric furnace or the like.
At a temperature of 30 minutes to 10 hours. The firing atmosphere is
In air, nitrogen, oxygen flow, nitrogen, oxygen substitution atmosphere,
A reduced pressure atmosphere and the like can be mentioned. The film thickness of each of the baked oxides is preferably 0.05 to 10 μm. Further, in order to increase the film thickness, the application of the same organometallic compound-containing solution and the thermal decomposition may be repeated.

As the structure of the multi-layer film, a solution containing an organic indium compound is applied onto a transparent substrate, and a transparent conductor film formed by thermal decomposition is coated with a solution containing one or more layers of an organometallic compound other than the organic indium compound. And a single-layer or multi-layer oxide film formed by thermal decomposition. In addition, an organic indium compound-containing solution is applied, a transparent conductor film formed by thermal decomposition is applied, or an organic metal compound-containing solution other than the organic indium compound of one layer or a multilayer is applied, and one layer formed by thermal decomposition or A metal film, an oxide film, or a nitride film formed by a method other than application of a solution containing an organometallic compound or thermal decomposition on the multilayer oxide film or as a layer between them, for example, a metal film, an oxide film, or a nitride film. It may include one layer or multiple layers such as a sulfide film.

When the functional film is formed by laminating and heat-treating a film which will be other functional film without depending on the application of the organometallic compound-containing solution and thermal decomposition, a sputtering method,
Either a dry method using a vacuum system such as a vapor deposition method, a CVD method, or a MOCVD method, a coating method using a paste similar to the transparent conductor film, or a wet method by printing can be used. The heat treatment of the laminated film is carried out by using an ordinary electric furnace (muffle furnace),
Local heat treatment using an infrared furnace, a belt furnace, or a laser may be performed. The heat treatment temperature may be equal to or lower than the softening temperature of the substrate, but improvement of crystallinity for the purpose of heat treatment,
When reducing defects, etc., usually 400 ° C to 1
About 100 ° C is used. Also, as the heat treatment atmosphere, if you do not like to be oxidized during heat treatment, nitrogen,
In addition to an inert atmosphere such as argon, or when reducing treatment is performed at the same time, in addition to this, reducing atmosphere such as hydrogen or water vapor is used. In addition, the atmosphere, oxygen, reduced pressure atmosphere, etc. may be mentioned.

Next, examples for carrying out the method for producing a multilayer film including the transparent conductor film of the present invention will be described.

[Example 1] (C ₈ H ₁₇ COO) ₃ In0.5g, (C ₈ H ₁₇ COO) _{3 In} , for producing a multilayer film structure having a cross section schematically shown in FIG. 1 according to the production method of the present invention.
₈ H ₁₇ COO) ₂ Sn 0.013 g dodecane 1.857 g
Dissolve in. This solution was applied to the quartz substrate 1 with a wire bar (# 10), dried at 45 ° C. for 30 minutes, and then baked in air at 800 ° C. for 1 hour to obtain In ₂ O ₃ / SnO.
₂ Obtain the membrane 2. This film 2 was a transparent conductor film, and had a sheet resistance of 0.8 kΩ / □, a visible light transmittance of 95%, and a film thickness of 0.2 μm.

On this transparent conductor film 2, 0.5 g of Si resinate (manufactured by NE Chemcat) and 1.
Apply 0g of solution with wire bar (# 10), 45 °
After being dried at C for 30 minutes, it is baked in air at 800 ° C. for 1 hour to obtain a SiO ₂ film 3 having a film thickness of 0.2 μm. Further, on the SiO ₂ film 3, (C ₈ H ₁₇ COO) ₂ Zn1.
66 g, Si resinate (manufactured by NE Chemcat) 0.5
A solution of 9 g of (C ₈ H ₁₇ COO) ₂ Mn (0.056 g) and terpineol (1.5 g) was applied with a wire bar (# 10), dried at 45 ° C. for 30 minutes, and then in air at 800 ° C.
C, and baked for 1 hour to obtain a Zn ₂ SiO ₄ film having a thickness of 0.3 μm:
A phosphor layer which is the Mn film 4 is obtained. Further, after depositing a SiO ₂ film 5 on the phosphor layer 4 in the same manner as described above, the Si 2
By depositing Al to a thickness of 0.5 μm on the O ₂ film 5 and providing the electrode layer 6, a multilayer film whose cross section is schematically shown in FIG. 1 was obtained. When a voltage of 150 V was applied to this multilayer film, green fluorescence was confirmed.

Next, in order to confirm the effect of the manufacturing method of the present invention, a comparative multi-layer film having a similar structure was manufactured by a conventional method so that it can be compared with the above-mentioned [Example 1] of the present invention. Example 1 will be described.

[Comparative Example 1] On a quartz substrate 1, In ₂ O ₃ /
SnO ₂ is vacuum-deposited to form an ITO transparent conductor film 2 having a thickness of 0.2 μm. On this transparent conductor film 2, the SiO ₂ film 3 and Zn ₂ S 3 were formed by the same method as in [Example 1].
iO ₄ : Mn film 4, SiO ₂ film 5 and Al film 6 are laminated, except that the transparent conductor film 2 is formed by vacuum vapor deposition.
A multilayer film having the same structure as in the above-mentioned [Example 1] was obtained.
Even if a voltage of 300 V is applied to this multilayer film, the color of fluorescence is
Not confirmed.

Vacuum-deposited ITO transparent conductor film (Comparative Example 1) and coating pyrolysis ITO transparent conductor film (Example 1)
As shown in Fig. 2, when comparing the heat resistance with
The resistance value of the TO transparent conductor film is not changed by heat treatment, while the resistance of the vacuum vapor deposition ITO transparent conductor film is high. Therefore, it is considered that no fluorescence was observed in the comparative example in which another film was laminated by the coating pyrolysis method on the vacuum-deposited ITO transparent conductor film. In addition to the vacuum-deposited ITO transparent conductor film, I prepared by the sputtering method
Also in the TO transparent conductor film, a phenomenon in which the resistance value increased due to the heat treatment similar to the vacuum deposition was observed.

Example 2 (C ₈ H ₁₇ COO) ₃ In0.
5 g of (C ₈ H ₁₇ COO) ₂ Sn 0.013 g of dodecane
Dissolve in 1.857g. Add this solution to a wire bar (# 1
0), it was applied to a quartz substrate, dried at 45 ° C for 30 minutes, and then baked in air at 800 ° C for 1 hour to form In ₂ O ₃
/ SnO ₂ film is obtained. The sheet resistance of this film is 0.8 kΩ
A transparent conductor film having a thickness of 0.2 μm and a visible light transmittance of 95% was obtained. A 2-ethylhexyl ammonium tungstate solution is applied onto this transparent conductor film by a spin coater and baked in air at 800 ° C. for 15 minutes to obtain a tungsten oxide film having a thickness of 0.2 μm.

The 2-ethylhexyl ammonium tungstate solution was prepared as follows. 20 ml of water and 40 ml of concentrated hydrochloric acid are added to 5.69 g of 2-ethylhexylamine.
Was added to prepare solution A. Also, tungstic acid 5.00
g, sodium hydroxide 16.0 g, water 60 ml,
Solution B was prepared. Solution B is gradually added to solution A, and further 2
-Ethylhexylamine 3.86 g was added, and methylene chloride 6
Extract 3 times with 0 ml. After distilling off the solvent from the organic layer,
50 ml of xylene and 14.86 g of 2-ethylhexyl ammonium linoleate were added to obtain a 2-ethylhexyl ammonium tungstate solution.

A tungsten oxide film formed on the transparent conductor film was formed with a NiO film as a counter electrode I
The TO-coated glass was arranged so that a gap of 20 μm was generated, and Li having a concentration of 1 mol / l was used as an electrolyte.
An electrochromic cell was prepared using a propylene carbonate solution of ClO ₄ .

When a DC voltage of 3 V was applied with the tungsten oxide film of this electrochromic cell as the negative electrode, E
CD changed to black blue, and the change in absorbance at 700 nm was 0.4 after 3 minutes from application of voltage. In addition, reverse the polarity 3
When V was applied, the black blue color disappeared. This coloring and decoloring could be repeated.

[Comparative Example 2] A quartz substrate was coated with In ₂ O ₃ / S.
A 0.2 μm thick ITO transparent conductor film is formed by vacuum evaporation of nO ₂ . On this transparent conductor film, in the same manner as in Example 2, by providing a tungsten oxide film, a counter electrode of NiO film and an electrolyte layer with a propylene carbonate solution of LiClO ₄ , a transparent conductor film is produced by vacuum vapor deposition. An electrochromic cell having the same configuration as in Example 2 except for the above was obtained. When a direct current of 3 V was applied with the tungsten oxide film of this electrochromic cell as a negative electrode, the ECD changed to black blue, and 700 minutes after the voltage was applied, 700
The change in absorbance at nm was 0.2.

[Example 3] First, 0.5 g of indium 2-ethylhexanoate and 0.046 of tin 2-ethylhexanoate were prepared.
To g, 4.0 g of n-dodecane was added and sufficiently stirred to make a uniform solution. Next, this solution was applied onto a glass substrate (Corning 7059) using a spin coater and baked in the air at 800 ° C. for 30 minutes. Then, the coating and baking steps are repeated to obtain a film thickness of 0.2 μm and 90Ω / □.
Of the transparent conductor film was prepared. Then, a stripe-shaped transparent conductor film was formed by photolithography.

A Ta ₂ O ₅ thin film was deposited on the transparent conductor film by sputtering to a thickness of 0.1 μm to form an insulating layer. Next, using a target of ZnS: Mn (containing 1 wt% as Mn concentration), a phosphor layer (light emitting layer) of 0.3 μm was deposited and laminated by an electron beam evaporation method. After that, heat treatment was performed in the air at 600 ° C. for 1 hour to improve the crystallinity. Furthermore, an insulating film similar to the above is laminated, and finally, an aluminum film is deposited by a resistance heating method to a thickness of 0.5 μm using a mask so as to intersect with the transparent conductor film, thereby forming a double insulating layer structure. A thin film EL device having

This thin film EL device has a light emission starting voltage of 150.
Amber yellow light emission was recognized at V / 1 KHz, and an EL device with high emission brightness was obtained.

[Comparative Example 3] An EL device was produced in the same manner as in Example 3 except that the transparent conductor film was produced by the electron beam evaporation method.

This thin film EL device has a light emission starting voltage of 25.
Light emission was first recognized at 0 V / 1 KHz, and the saturated emission luminance was lower than that in Example 3.

[Example 4] A transparent conductor film was prepared in the same manner as in Example 3, except that the substrate was replaced with a quartz substrate. Si is sputtered on this transparent conductor film.
An O ₂ thin film was deposited to a thickness of 0.1 μm to form an insulating layer. next,
A phosphor paste having the following composition was applied onto the insulating layer by spin coating, and baked at 800 ° C. for 30 minutes in the atmosphere to deposit a phosphor film (light emitting layer). Then, it heat-processed at 1000 degreeC in the air for 3 hours.

Next, after forming an insulating layer similar to the above,
Finally, an aluminum film was deposited to a thickness of 0.5 μm by a resistance heating method using a mask so as to intersect with the transparent conductor film, to fabricate a thin film EL device having a double insulation structure.

Phosphor paste (composition for forming light emitting layer) 2-ethylhexanoic acid Zn 1.42 g Si resinate (manufactured by NE Chemcat) 0.28 g 2-ethylhexanoic acid Mn 0.03 g PBMA 10 wt% α-terpineol Solution 1.73 g Dioctyl phthalate 1.73 g Linoleic acid 1.73 g

This thin film EL device has a light emission starting voltage of 100.
Green light emission was observed at V / 1 KHz, and an EL device with high emission brightness was obtained.

Comparative Example 4 An EL device was manufactured by the same method as in Example 4 except that the transparent conductor film was manufactured by the electron beam evaporation method.

This thin film EL element is 300 V / 1 KHz
No light emission was observed even when the above voltage was applied.

The present invention relates to a method for producing a multi-layer film containing a heat-resistant transparent conductor film in the lower layer. In the above-mentioned examples, the thin-film EL device and the electrochromic cell were produced. The present invention is not limited to these examples as long as it includes a process of forming a functional transparent conductive film, depositing another functional film thereon, and then performing heat treatment.

[0051]

As described above, according to the present invention, a solution containing an organic indium metal compound is applied onto a transparent substrate by coating or printing, and then thermally decomposed to form an indium oxide-containing transparent conductor film. Since the transparent conductor film is formed using a relatively high temperature process, even if heat equal to or higher than that in the manufacturing process is applied thereafter,
The resistivity does not change, and therefore, the device performance is not deteriorated even if a film to be a functional film is laminated on this film and then further heat-treated.

Since a transparent conductor film, an insulating film, and a phosphor film are laminated in an EL element or the like, and then the heat treatment for further improving the crystallinity of the phosphor film does not change the resistivity of the transparent conductor film. The EL element characteristics such as the light emission starting voltage and the brightness are not deteriorated.

Further, according to the present invention, when a laminated film requiring a transparent conductor film is produced, a relatively high temperature process is required, and a heat treatment is required after the film formation for the purpose of improving the film quality. Great effect in some cases.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing a configuration example of a multilayer film including a transparent conductor film according to the present invention.

FIG. 2 is a diagram showing a comparison in resistance change of a transparent conductor film between a conventional method and a method of the present invention.

[Explanation of symbols]

 1 Quartz Substrate 2 Transparent Conductor Layer 3 Insulating Layer 4 Phosphor Layer 5 Insulating Layer 6 Electrode Layer

Claims (3)

[Claims] 1. An organic indium compound-containing solution is applied onto a transparent substrate and thermally decomposed to form an indium oxide-based transparent conductor film, and then directly or indirectly on the transparent conductor film. A method for producing a multilayer film including a transparent conductor film, characterized in that the functional film is formed by a process including a heating process. 2. A process, including the heating process, comprising:
The method for producing a multilayer film including a transparent conductor film according to claim 1, which is a process of applying an organic metal compound solution and thermally decomposing it to form a metal oxide film as the functional film. 3. A process, including the heating process, comprising:
The method for producing a multilayer film including a transparent conductor film according to claim 1, which is a process of forming the functional film by laminating a film to be a functional film and then performing heat treatment.