JPH0137816B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming metal oxide coatings by a lift-off method, and more particularly, by screen printing on a substrate using a flammable ink containing a thermosetting organic binder. The present invention provides an effective method for forming a pattern of a metal oxide film on a substrate by applying a coating liquid for forming a metal oxide film thereon and then performing high temperature treatment.

(Prior Art) Conventionally, materials in which oxide films of various metals are formed on substrates such as glass, ceramics, and metal plates have been used for various purposes. For example:

Indium oxide (In ₂ O ₃ ) and tin oxide (SnO ₂ ) as transparent conductive films.

Silicon oxide (SiO ₂ ), titanium oxide (TiO ₂ ), aluminum oxide (Al ₂ O ₃ ), cerium oxide (CeO ₂ ), zirconium oxide (ZrO ₂ ), as an insulating film or alignment film for transparent electrodes for liquid crystal cells,
Tantalum oxide (Ta ₂ O ₅ ).

Tungsten oxide (WO ₃ ), molybdenum oxide (MoO ₃ ) as electrochromic displays.

Titanium oxide-tin oxide (TiOx-SnOx) as a humidity sensor.

Zinc oxide (ZnO), tin oxide (SnO ₂ ), titanium oxide (TiO ₂ ), zirconium oxide (ZrO ₂ ), and iron oxide (Fe ₂ O ₃ ) as gas sensors.

The method of patterning these metal oxide films is to first deposit a metal oxide film on the entire surface of the substrate by a dipping method, a vacuum evaporation method, a CVD method (Chemical Vapor Deposition), or a sputtering method. A method in which only unnecessary portions are removed by photoetching is generally used.

However, these methods have drawbacks such as a large number of steps such as deposition of photoresist on the metal oxide film, exposure, development, and etching, making proper process control difficult and increasing production costs.

In addition, as a method other than photoetching,
First, a patterned mask punched out of a stainless steel plate or the like is placed on a substrate, and a metal oxide film is formed only on the punched out part by vacuum evaporation or CVD (Japanese Patent Application Laid-Open No. 1986-1999-1).
No. 163055).

In this method, if the mask warps even a little, highly accurate patterning becomes impossible.

Another method is to form a resist pattern on the substrate, apply a metal oxide film over the entire surface, harden the metal oxide film at high temperature, generate cracks in the metal oxide film on the resist, and then peel it off. There is a method in which the resist and the metal oxide film on the resist are removed by treatment with a liquid, and the remover permeates through the cracks to remove the resist and the metal oxide film on the resist, but it takes time to pattern the resist and is difficult to remove. There are problems such as (Japanese Patent Application Laid-Open No. 116782/1982).

Another method is to print resist ink on the metal oxide film formed on the substrate by screen printing, and then use the ink area as a mask to etch the metal oxide film. However, when considering the chemical resistance of resist inks and metal oxide coatings, there are considerable restrictions and only a limited number of metal oxide coatings can be used.

As described above, there are still various difficulties in the method of forming metal oxide films, and there is a need for an effective method that allows easy film formation and requires fewer processing steps.

(Purpose of the Invention) The present inventors have conducted extensive research to develop a method for forming patterns of metal oxide films that is easy to form, requires a short processing time, and is versatile. , has completed the present invention.

(Structure of the Invention) The present invention provides a method for applying a mixture or a mixture of at least two selected from a hydroxyl group-containing organic binder, a carboxyl group-containing organic binder, and a glycidyl group-containing organic binder on a substrate such as glass, ceramics, metal, etc. Screen printing on a substrate using a flammable ink containing a thermosetting organic binder (hereinafter simply referred to as flammable ink) consisting of the organic binder and a mixture of a compound that undergoes a thermosetting reaction with the organic binder. A pattern is formed by thermally curing the flammable ink, and then a coating solution for forming a metal oxide film is applied to the entire surface and a baking process is performed to form a metal oxide film on the substrate. Then, the flammable ink area is burned out, and the metal oxide film on the ink area is also removed to form a metal oxide film on the non-printed area on the substrate. This is the formation method.

(Coating liquid for forming a metal oxide film) Any coating liquid for forming a metal oxide film used in the present invention may be used as long as it is in the form of a solution that can form a metal oxide film by firing. It can also be used for things. For example, as follows.

(a) In the case of indium oxide, a coating solution consisting of a reaction product of indium nitrate and β-diketone or a mixture of indium nitrate, β-diketone and an organic solvent.

(b) In the case of tin oxide, tetraalkoxytin (alkyl group has 1 to 20 carbon atoms) dissolved in alcohol, ester, ketone, or ether.

(c) In the case of silicon oxide, it is a reaction product obtained by reacting an alkoxysilane or a halogenated silane with a mixture of a lower carboxylic acid and an alcohol in the presence of an organic acid reaction promoter.

(d) In the case of titanium oxide, it is a mixture of carboxylic acid and titanium halide, and the product is reacted with alcohol.

(e) In the case of aluminum oxide, a reaction mixture obtained by reacting an aluminum alcoholate with a fatty acid or fatty acid anhydride and an alcohol in the presence of a reaction promoter.

(f) In the case of cerium oxide, a mixture of cerium nitrate in methanol, ethanol, methyl acetate, ethylene glycol monoethyl ether as a solvent, and butyral resin dissolved therein.

(g) In the case of zirconium oxide, the reaction product mixture of zirconium alcoholate and fatty acid anhydride in the presence of nitric acid in an alcoholic solvent.

(h) In the case of tantalum oxide, the reaction product mixture of tantalum ethoxide with alcohol and fatty acid anhydride.

(i) In the case of tungsten oxide, a mixed solution is prepared by dissolving phosphotungstic acid in acetone, adding an ethanol solution of polyvinyl butyral, and further adding ethylene glycol monomethyl ether.

(j) In the case of molybdenum oxide, a mixture of phosphomolybdic acid dissolved in acetone, an ethanol solution of polyvinyl butyral, and ethylene glycol monomethyl ether added thereto.

(k) In the case of zinc oxide, a mixture of zinc acetylacetonate in ethyl acetate, methanol, β-diketone as a solvent, and a ketone resin dissolved therein.

(l) In the case of iron oxides, a solution of iron naphthenate in butanol.

(Flammable ink) The flammable ink used in the present invention basically consists of a thermosetting organic binder and an organic solvent. It is a mixture of at least two selected from a group-containing organic binder and a glycidyl group-containing organic binder, or it is composed of these organic binders and a compound that undergoes a thermosetting reaction with the organic binder.

(b) Hydroxyl group-containing organic binder A homopolymer or copolymer of 2-hydroxyethyl (meth)acrylate or 2-hydroxypropyl (meth)acrylate, butyral resin, acetal resin, or polyester resin.

(b) Carboxyl group-containing organic binder Styrene-maleic acid copolymer, carboxyl group-modified polybutadiene, (meth)acrylic acid homopolymer or copolymer.

○Glycidyl group-containing organic binder Epoxy resin, epoxy-modified polybutadiene.

When an ink prepared from the above three types of organic binders alone and an organic solvent is applied and dried, and a coating solution for forming a metal oxide film is applied thereon without any other treatment, the ink layer is The following problems arise due to contact with the organic solvent of the coating solution for forming a metal oxide film.

The ink layer is dissolved or swelled by the coating liquid.

Smearing or clouding occurs in the metal oxide layer.

Due to poor combustion, carbon remains even after firing, and combustion residues adhere firmly to the substrate surface.

As the ink burns off, the coated film on the ink sinks and adheres to the substrate.

It is difficult to clean and remove combustion residue.

In order to solve these problems, the present invention employs a method of thermally curing the ink layer after applying the ink. For this purpose, it is necessary to add something that undergoes a thermosetting reaction with the organic binder, or to cause a curing reaction using a combination of organic binders.
For example, for the binder of ○B, the binder of ○B or ○C, for the binder of ○B, the binder of ○A or ○C,
Moreover, the purpose can be achieved by mixing the binder of ○C or ○B with the binder of ○A or ○B.

As for the material that undergoes a thermosetting reaction with the organic binder, the purpose can be achieved even with a low molecular weight material other than a resin. Examples of such substances are as follows.

For the binder ○B or ○C, glycerin, triethylene glycol, polyethylene glycol (molecular weight 400 or less) containing hydroxyl groups,
Trimethylolpropane, pentaerythritol, dipentaerythritol, phenolic resin.

Maleic acid, phthalic acid, tartaric acid, and succinic acid containing a carboxyl group are used as the binder for ○A or ○C.

For the binder ○A or ○B, a polyvalent glycidyl compound such as 1,4-diglycidylbutane containing a glycidyl group.

In addition, for the binders ○A, ○B or ○C, methylolurea, methylated methylolurea, butylated methylolurea, methylolmelamine, methylated methylolmelamine, butylated methylolmelamine,
Resorcinol resin.

Next, as the organic solvent used for the flammable ink in the present invention, any organic solvent can be used as long as it dissolves the thermosetting organic binder, but organic solvents with a boiling point of 140 to 300°C at atmospheric pressure can be used. A range of items can be used. Preferably, it is convenient to use one having a temperature of 170 to 260°C. If the temperature is below 140°C, drying will be too fast, which will have a negative effect on the smoothness of the coating film, and will also dry the screen plate and cause clogging of the screen mesh. If the temperature is 300°C or higher, the smoothness is good, but the drying property is poor and it is uneconomical. Suitable solvents that meet these various conditions include, for example, methyl carbitol, ethyl carbitol, butyl carbitol, methyl carbitol acetate, ethyl carbitol acetate, butyl carbitol acetate, ethylene glycol monobutyl ether, ethylene glycol monoethyl Derivatives of high-boiling polyhydric alcohols such as ether, ethylene glycol monoethyl ether acetate, methoxybutyl acetate, diacetone alcohol, isophorone, diisobutyl ketone, ethylene glycol monobutyl ether acetate, pine oil, terpineol, 2-ethylhexyl acetate, etc. A single or mixed solvent of ketones, esters, and terpenes is used. Ink property aids can also be used if desired. Examples include nitrocellulose, ethylcellulose,
Acrylic fine powder and silicon oxide fine powder Modaflow (manufactured by Monsanto) are available. These have effects as thickeners, thixotropic agents and leveling improvers.

In addition, if desired, it is possible to prevent flammable ink or metal oxide coating from adhering to the substrate after firing,
An inorganic binder can also be added to prevent scattering into the firing furnace. Suitable materials for this purpose include oxides such as aluminum (Al), titanium (Ti), silicon (Si), tungsten (W), barium (Ba), and zinc (Zn), as well as barium sulfate (BaSO ₄ ) and barium carbonate. (BaCO ₃ ) and calcium carbonate (CaCO ₃ ) fine powder.

The proportions of each component in the flammable ink vary considerably depending on how they are combined, but the following ranges are preferred.

Thermosetting organic binder 100 parts by weight Low molecular weight binder 0-80 parts preferably 0-40 parts by weight Organic solvent 100-5000 parts by weight Ink property aid
0 to 150 parts by weight, preferably 0 to 50 parts by weight Inorganic binder 0 to 100 parts by weight (Procedure) Next, the method of the present invention will be explained in more detail with reference to the attached drawings. The flammable ink 2 is screen printed on the area where the oxide film is not formed, and is thermally cured by baking in an atmosphere of 150 to 200°C for 10 to 30 minutes to make the ink sparingly soluble (see Figure 1).

Next, a coating solution for forming a metal oxide film is applied by a conventional spray method, brush coating method, roll method, dipping method, or the like. For example, when a dipping method is used, the coating liquid is applied at a dipping and pulling speed of 10 to 50 cm/min.

In addition, if the film has poor drying properties, 100 to 250
Pre-bake for 5-15 minutes at °C.

Furthermore, when coating is performed by the dipping and pulling method, metal oxide coatings are obtained on both the front and back surfaces of the substrate as shown in FIG.

followed by a temperature of at least 350°C, preferably
Baking is performed in a furnace at 450° to 600°C for about 30 minutes to obtain a metal oxide film, and the flammable ink area 2 is burned off, the metal oxide film on the ink area is also removed, and the metal oxide film is removed. (See Figure 3).

(Operations/Effects) As detailed above, the present invention uses a flammable ink containing a thermosetting organic binder, and after the ink layer is cured, the coating for forming a metal oxide film is applied. When the liquid is applied, the ink layer does not dissolve or swell in the coating liquid, nor does it bleed or become cloudy.

Furthermore, during firing, carbon due to poor combustion does not remain on the substrate, and combustion residue is easy to clean and peel off, making it easy to form a metal oxide film, shortening the processing time, and making it a versatile product. This is an effective method for patterning a metal oxide film that can form a clear pattern.

EXAMPLES Next, examples of the present invention will be described to further specifically explain the present invention, but the following examples are not intended to limit the present invention in any way.

Example 1 Silicon oxide (SiO ₂ ) film formed on a glass substrate,
When patterning a transparent conductive film.

(Ink composition used) Styrene-maleic acid copolymer 27 parts by weight diglycerol polyglycidyl ether 8 parts by weight Ethylene glycol monoethyl ether acetate 36 parts by weight Carbitol acetate 18 parts by weight H ₂ WO ₄ fine powder 1 part by weight Aerosil R- 972 (Silicon oxide manufactured by Nippon Aerosil Co., Ltd.) 10 parts by weight (Transparent conductive coating coating liquid) Using TCG coating liquid manufactured by Tokyo Ohka Kogyo Co., Ltd. (Coating liquid for forming In ₂ O ₃ ) After screen printing the ink having the above composition, After baking at 170℃ for 20 minutes and washing with 2% NaOH solution, pure water, isopropyl alcohol, and fluorine solvent in this order, apply the above coating solution at a lifting speed of 15cm/min, and prebaked at 250℃ for 5 minutes. at °C
After baking for 30 minutes, add 2% by weight NaOH solution.
After ultrasonic cleaning for a minute, the film thickness was approximately 500 Å.
A good film pattern of about 2 kΩ/□ was formed.

Example 2 On a substrate having a patterned transparent electrode, excluding the connection lead terminal part with the external terminal
An example of patterning an insulating film of SiO ₂ film.

(Ink composition used) 2-hydroxypropyl methacrylate monopolymer 16 parts by weight Epicoat 152 (Ciel Chemical)...Epoxy resin
6 parts by weight Ethylene glycol monobutyl ether 30 parts by weight Ethyl carbitol 30 parts by weight Nitrocellulose 3 parts by weight Al ₂ O ₃ fine powder 6 parts by weight Aezil #300 (silicon oxide manufactured by Nippon Aerosil Co., Ltd.)
9 parts by weight (SiO ₂ film coating liquid) Tokyo Ohka Kogyo Co., Ltd. OCDTYPE
SiO ₂ film forming coating solution for silica film) Screen print the ink with the above composition onto the lead terminals, bake at 180°C for 20 minutes, and then apply detergent and
Wash with pure water and fluorine-based solvent in that order, and apply the above coating solution.
Dip coating at a pulling speed of 30cm/min, 140℃
After pre-baking for 10 minutes at 500℃, baking for 30 minutes,
When this was ultrasonically cleaned for 3 minutes with a 2% by weight NaOH solution, an insulating film with a thickness of about 1200 Å was obtained, and the lead terminal portion showed good conductivity, which was no different from before the insulating film was formed.

Example 3 A case where a patterned electrochromic film is formed on a glass substrate having a transparent conductive film.

(Ink composition used) Byron 200 (polyester manufactured by Toyobo Co., Ltd.) 32 parts by weight Methoxymelamine 13 parts by weight Carbitol acetate 40 parts by weight Butyl acetate 8 parts by weight TiO ₂ Fine powder 2 parts by weight Aerosil #380 (Silicon oxide manufactured by Nippon Aerosil Co., Ltd.) 5 Part by weight: Screen print the ink of the above composition on glass with a transparent electrode film, bake at 180°C for 15 minutes,
A solution of 10 g of phosphotungstic acid dissolved in 10 g of acetone was applied to a substrate that had been cleaned in the following order: 2% NaOH, pure water, isopropyl alcohol, and a fluorine-based solvent.
A coating solution containing 50 g of 15% polyvinyl butyral ethyl alcohol solution and 30 g of ethylene glycol monomethyl ether was pulled up and applied at 25 cm/min, prebaked at 100°C for 15 minutes, and then heated to 500°C.
When the product was fired for 60 minutes and then subjected to ultrasonic cleaning in the order of neutral detergent, pure water, and trichlorethylene, a good electrochromic film pattern was formed.

Comparative example [Example using only one type of organic binder] (Ink composition used) Dianal BR-75 (Acrylic resin manufactured by Mitsubishi Rayon Co., Ltd.) 22 parts by weight Butyl cellosolve 30 parts by weight Ethyl carbitol 30 parts by weight Nitrocellulose 3 Part by weight Al ₂ O ₃ fine powder 6 parts by weight Aerosil #300 (silicon oxide manufactured by Nippon Aerosil Co., Ltd.) 9 parts by weight The ink consisting of the above composition was screen printed on glass with a transparent electrode film and baked at 180°C for 15 minutes. As a result, sagging was observed in the ink pattern due to heating. Next, a SiO ₂ film was formed on this substrate in the same manner as in Example 2. However, in addition to the ink sagging due to heating, the ink also dissolved when it came into contact with the SiO ₂ film forming coating solution, making it impossible to obtain an insulating film pattern.

[Brief explanation of drawings]

1 to 3 are explanatory diagrams showing the steps of the oxide film pattern forming method of the present invention. 1st
The figure shows a state in which flammable ink is printed on areas where a metal oxide film is not desired to be formed, and Figure 2 shows a state in which a coating liquid for forming a metal oxide film is applied after the flammable ink layer in Figure 1 has been cured. , FIG. 3 shows a state in which a metal oxide film remains on the substrate after firing. The symbols in the drawings indicate the following. DESCRIPTION OF SYMBOLS 1...Substrate, 2...Flammable ink, 3...Coating liquid for metal oxide film formation, 4...Metal oxide film.

Claims (1)

[Claims] 1 A mixture of at least two selected from hydroxyl group-containing organic binders, carboxyl group-containing organic binders, and glycidyl group-containing organic binders, or a mixture of the organic binder and a compound that undergoes a thermosetting reaction with the organic binder. Using a flammable ink containing a thermosetting organic binder consisting of a mixture, screen printing is performed on the substrate, the ink is thermally cured, and then a coating liquid for forming a metal oxide film is applied to the entire surface, A process for forming a metal oxide film on a substrate by firing, and then burning off the flammable ink area and leaving the metal oxide film only on the non-printed areas on the substrate. Pattern formation method.