JPH0336250B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming a metal oxide film by a lift-off method, and more specifically, the present invention relates to a method for forming a metal oxide film by a lift-off method, and more specifically, a method for forming a metal oxide film by screen printing on a substrate using a paste ink containing a polymer insoluble in an alcohol solvent. To provide an effective method for forming a clear pattern of a metal oxide film on a substrate by applying a metal oxide film-forming agent containing an alcohol-based solvent as a main solvent thereon, and then heat-treating the material. It is.

(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:

(1) Indium oxide (In ₂ O ₃ ) and tin oxide (SnO ₂ ) as transparent conductive films; (2) Silicon oxide (SiO ₂ ) and oxide as insulating films for transparent electrodes of liquid crystal display cells or alignment films. Titanium (TiO ₂ ), aluminum oxide (Al ₂ O ₃ ), cerium oxide (CeO ₂ ), zirconium oxide (ZrO ₂ ), tantalum oxide (Ta ₂ O ₅ ), (3) Tungsten oxide as an electrochromic display (WO ₃ ), molybdenum oxide (MoO ₃ ) (4) Titanium oxide-tin oxide (TiOx-SnOx) as a humidity sensor (5) Zinc oxide (ZnO), tin oxide (SnO ₂ ), titanium oxide as a gas sensor (TiO ₂ ), zirconium oxide (ZrO ₂ ), iron oxide (Fe ₂ O ₃ ), etc.

Methods for patterning these metal oxide films include dipping, vacuum evaporation, and CVD.
Generally, a method is used in which a metal oxide film is first deposited on the entire surface of the substrate by a chemical vapor deposition method or a sputtering method, and only unnecessary portions are removed by a photoetching method.

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

Another method other than photoetching is to first place a patterned mask on a stainless steel plate on the substrate, and then form a metal oxide film only on the punched areas by vacuum evaporation or CVD. Yes (Japanese Patent Application Publication No. 1973-
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, and generate cracks in the metal oxide film on the resist, and then apply a stripping solution. There is a method in which the resist and the metal oxide film on the resist are peeled off and removed by treatment with a stripping solution that permeates through the cracks (Japanese Unexamined Patent Application Publication No. 1983-1999).
No. 116782), however, there are problems such as it takes time to pattern the resist and it is difficult to peel it off.

Another method is to apply 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. There are considerable limitations when considering the chemical resistance of ink and metal oxide coatings.
Only limited metal oxide coatings can be used.

As described above, there are still various difficulties in the method of forming a metal oxide film, and there is a strong demand for an effective method that allows the film to be easily formed and requires fewer processing steps.

(Purpose of the Invention) The present inventors have conducted extensive research to develop an effective method for forming versatile patterns of metal oxide films in large quantities, easily, and in a short processing time. As a result, the present invention has been completed.

(Structure of the invention) The present invention comprises a saturated polyester resin, a cyclized rubber,
Using a paste ink whose main component is a polymer insoluble in one or more alcoholic solvents selected from homopolymers of acrylic esters or methacrylic esters, copolymers of acrylic esters or methacrylic esters, After screen printing a desired pattern on a substrate such as glass, ceramics, metal, etc. and drying the ink at a temperature of approximately 100 to 300°C, metal oxidation using alcohol as the main solvent is applied to the entire surface of the substrate. A metal oxide film forming agent is applied, heat treated at a temperature of about 100 to 300°C, and then the paste-like ink printed area is dissolved and removed using an organic solvent, and the metal oxide film forming agent on the ink printed area is removed. This is a method for forming a pattern of a metal oxide film, which is characterized in that the metal oxide film is removed on the non-printing portion of the substrate by further baking at a temperature of 150° C. or higher to form a metal oxide film on the non-printing portion of the substrate.

(Metal oxide film forming agent) The metal oxide film forming agent used in the present invention must satisfy the following conditions.

(1) Approx.
When heat treated at a temperature of about 100 to 300°C, it becomes insoluble in any of the following solvents: halogenated hydrocarbons, aliphatic hydrocarbons, esters, ketones, polyhydric alcohols, or their derivatives.

(2) The film coated with metal oxide film forming agent is 150%
Forms a strong metal oxide film by firing at temperatures above ℃.

(3) As a solvent, an alcohol-based solvent alone or a mixed solvent consisting of an ester-based, ketone-based, or aliphatic hydrocarbon-based solvent containing 70% by weight or more of an alcohol-based solvent can be used.

Examples of metal oxide film forming agents that meet these conditions include the following.

(1) In the case of silicon oxide, the reaction mixture obtained by hydrolyzing 100 parts by weight of tetraalkoxysilane, 50 parts by weight of water, and 100 parts by weight of ethyl alcohol in the presence of hydrochloric acid is diluted with alcohol to make it easier to apply. (Japanese Unexamined Patent Publication No. 51-42092
Another method is to apply a reaction mixture obtained by reacting 100 parts by weight of an alkoxysilane, 120 parts by weight of a lower carboxylic acid, and 100 parts by weight of ethyl alcohol in the presence of 8 parts by weight of an organic acid. (2) In the case of titanium oxide, titanium alcoholate is diluted with alcohol to make it easier to use.
(3) In the case of aluminum oxide, 100 parts by weight of aluminum alcoholate is reacted with 180 parts by weight of ethyl alcohol.
Dissolved in a mixture of parts by weight and 40 parts by weight of an inorganic acid, reacted with 60 parts by weight of fatty acid anhydride, and diluted with alcohol to make it easier to apply (Japanese Patent Application No. 55-21382); (4) In the case of cerium oxide, ceric nitrate
20 parts by weight, 200 parts by weight of methyl alcohol, 100 parts by weight of ethyl alcohol, methyl acetate
20 parts by weight, 100 parts by weight of ethylene glycol monoethyl ether, butyral resin (average degree of polymerization
(5) In the case of zirconium oxide, 271.3 parts by weight of zirconium ethylate and 450 parts by weight of ethyl alcohol.
(6) In the case of tantalum oxide, 406 parts by weight of tantalum ethoxide and 368 parts by weight of ethyl alcohol are added to a reaction mixture of 120 parts by weight and glacial acetic acid. (7) In the case of zinc oxide, zinc ethylate
(8) In the case of iron oxide, nitric acid 100 parts by weight of ferric iron,
A mixture consisting of 100 parts by weight of acetylacetone, 200 parts by weight of methyl alcohol, and 500 parts by weight of ethylene glycol monoethyl ether; (9) In the case of tin oxide, 100 parts by weight of ethyl alcohol.
parts by weight, and 20 parts by weight of tin dimethyl dichloride (Japanese Patent Publication No. 14831/1983).

(Paste ink) After applying a commercially available screen printing ink or a paste ink made of a thermosetting resin such as epoxy resin, phenolic resin, phenolic resin, or melamine resin onto a substrate, ink is then applied as described above. When a metal oxide film forming agent is applied and heat treated, the following problems occur.

(1) When applied, the ink layer dissolves in the organic solvent in the film forming agent.

(2) Smearing or clouding occurs in the metal oxide film.

(3) The ink layer cracks during heat treatment.

(4) The ink layer undergoes thermal crosslinking during heat treatment, making it difficult to peel off the ink layer.

It is thought that both problems are caused by the organic solvent in the metal oxide film forming agent coming into contact with the ink layer and having an adverse effect when the metal oxide film forming agent is applied onto the ink layer.

In the present invention, this problem was solved by limiting the main solvent of the metal oxide film forming agent to an alcohol solvent and using a paste ink containing a polymer insoluble in alcohol solvents.

That is, the paste ink used in the present invention is one or more selected from saturated polyester resins, cyclized rubbers, homopolymers of acrylic esters or methacrylic esters, and copolymers of acrylic esters or methacrylic esters. The main component is a polymer that is insoluble in alcoholic solvents.

In order to prepare a pasty ink, it is necessary to dissolve the above polymer in an organic solvent. As the organic solvent for this purpose, those having a boiling point at atmospheric pressure in the range of 140 DEG to 300 DEG C. can be used, and a boiling point of 170 DEG to 260 DEG C. is more convenient. If the boiling point is below 140°C, the ink dries too quickly after screen printing, which has a negative effect on the smoothing of the coating film, and also dries the screen plate, causing clogging of the screen mesh. If the boiling point is 300° C. or higher, the smoothness is good, but the drying property is poor, and it takes a long time to proceed to the next step, which is not favorable for work. Suitable organic solvents that satisfy these various points include, for example, methyl carbitol acetate, ethyl carbitol acetate, butyl carbitol acetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, isophorone,
Diisobutyl ketone, benzoic acid methyl ester,
Pine oil, turpentine oil, tetralin, decalin,
High boiling point solvents such as 2-ethylhexyl acetate or the like may be used alone or in combination. Further, if desired, an adhesion improver, an inorganic binder, and an ink property aid may be added.

Addition of an adhesion improver not only strengthens the adhesion between the ink and the substrate, but also has the effect of preventing cracks that occur when the ink dries. Examples of suitable resins include ketone resins, xylene resins, liquid butadiene resins, etc., and the amount thereof added is preferably in the range of 0 to 35% by weight based on the polymer.

Addition of an inorganic binder has the effect of preventing cracking, similar to the adhesion improver. A suitable amount thereof added is 0 to 100% by weight based on the polymer, and fine powders of oxides such as aluminum oxide, titanium oxide, and silicon oxide may be used.

Examples of ink property aids include nitrocellulose, ethylcellulose, acrylic resin fine powder, silicon oxide fine powder, and Modaflow (manufactured by Monsanto). These have the effect as thickeners, thixotropic agents, leveling agents and foam suppressants. The amount used is 0 to 150 parts by weight, preferably 0 to 50 parts by weight per 100 parts by weight of the polymer.

(Organic Solvent) In the present invention, the organic solvent used to remove the paste-like ink printed area and the metal oxide film on the ink printed area after applying the metal oxide film forming agent on the substrate and heat-treating the substrate is , halogenated hydrocarbon type, aliphatic hydrocarbon type, ester type, depending on the type of metal oxide film forming agent used.
Any one of ketones, polyhydric alcohols and derivatives thereof is appropriately selected and used.

(Embodiments) Next, the method of the present invention will be described in more detail with reference to the accompanying drawings. Paste ink 2 is applied to the non-forming area of the metal oxide on the base material 1 by screen printing, and the ink is dried by heating in an atmosphere of 100 to 300°C for 10 to 30 minutes (see Figure 1). .

Next, a metal oxide film-forming agent is applied by a conventional spray method, brush coating method, roll method, dipping and pulling method, or the like. For example, when using the immersion pulling method, the above-mentioned forming agent is applied at a pulling speed of 10 to 50 cm/min, and the metal oxide film forming agent is dried by heating in an atmosphere of 100 to 300°C for 10 to 30 minutes. and imparts solvent resistance. When the coating is applied by the dipping and pulling method, layers of the metal oxide film-forming agent are obtained on both the front and back surfaces of the substrate as shown in FIG. Further, in this heat treatment stage, minute cracks 5 are generated only in the metal oxide film on the ink layer, presumably due to the difference in expansion coefficient between the ink layer and the metal oxide film forming agent.

Subsequently, it is brought into contact with an organic solvent. For example, when the crack is immersed in an organic solvent that is being stirred, immersed in an organic solvent that has been irradiated with ultrasonic waves, or exposed to organic solvent vapor, the organic solvent will penetrate through the cracks and cause the ink layer and the cracks to deteriorate. The metal oxide film that has entered is removed, and then heated at 150 to 1000°C, preferably 300°C.
When fired for 30 to 60 minutes in a firing furnace at ~600℃,
Obtaining a pattern of the metal oxide film 4 (see Figure 3) (Operation/Effect) As described above, the present invention is a method of forming a pattern on a substrate using a paste ink containing a polymer insoluble in alcoholic solvents. Screen printing is performed, and a metal oxide film forming agent containing an alcohol-based solvent as the main solvent is applied on top of the screen printing, followed by heat treatment.
After that, only unnecessary portions of the metal oxide film are removed using an organic solvent, so that the pattern of the metal oxide film does not become disordered, blurred, cloudy, or cracked. Further, according to the present invention, since the parts not required for coating are washed with an organic solvent, there is no stain, and the metal oxide coating can be easily formed and a clear pattern can be obtained.

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 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) Acrylic resin BR-75 (manufactured by Mitsubishi Rayon Co., Ltd.)
18 parts by weight Ethylene glycol monoethyl ether acetate 54 parts by weight Ethyl carbitol acetate 18 parts by weight Aerosil R-972 (Silicon oxide fine powder manufactured by Nippon Aerosil Co., Ltd.) 10 parts by weight (Formation of SiO ₂ film) JP-A-1988- Based on the method of 42092, 42 g of ethyl ortho-silicate, 11 g of water and 115 ml of methyl alcohol
g and stirred for 5 hours in the presence of 0.08 ml of hydrochloric acid, the product of the hydrolysis reaction was used as a metal oxide forming agent (hereinafter referred to as coating solution), and the ink with the above composition was applied to the lead terminals on the board. screen print,
After drying at 160℃ for 10 minutes, apply the above coating solution at 36cm/min.
The film was applied by dip coating at a pulling speed of 1, pre-baked at 160°C for 15 minutes to harden the film, then ultrasonically cleaned with trichlorethylene solution for 2 minutes, and then steam-cleaned with trichlorethylene to remove the ink area and the film on the ink area. It was also removed and patterned. When this was further baked at 500℃ for 30 minutes, the film thickness was
A 1300 Å thick insulating film was patterned, and the lead terminals showed good conductivity, no different from before the insulating film was formed.

Example 2 An example of patterning a TiO ₂ film by partially opening a window on a substrate having a transparent electrode.

(Ink composition used) Saturated polyester resin Vitel PE-200 (Gutsdeyer Tire & Rubber Company) 32 parts by weight Ketone resin Hilux 111 (Hitachi Chemical) 8 parts by weight Ethylene glycol monoethyl ether acetate 8 parts by weight Ethyl carbitol acetate Tart 48 parts by weight Modaflow (Monsanto) 1 part by weight Aerosil R-972 (Japan Aerosil)
3 parts by weight (Formation of TiO ₂ film) After stirring and reacting 57 g of titanium iso-propylate, 24 g of glacial acetic acid, and 148 g of ethyl alcohol for 3 hours,
The solution obtained by standing still for one day is used as a coating solution, and an ink having the above composition is screen printed on a substrate,
After drying at 140℃ for 15 minutes, apply the above coating solution at 20cm/min.
The film was applied by dip coating at a lifting speed of 200°C, pre-baked at 180°C for 20 minutes to harden the film, ultrasonically cleaned with trichlorethylene for 2 minutes, and then steam-cleaned with trichlorethylene to remove the ink area and the film on the ink area. It was also removed and patterned. When this was further baked at 500℃ for 30 minutes, the film thickness was approx.
A 700 Å insulating film was patterned, and the transparent electrode in the window area showed good conductivity.

Example 3 An example of patterning a SiO ₂ film on a substrate requiring a transparent electrode.

(Ink composition used) Cyclized rubber (Alpex Ck-514) Hoechst Japan Co., Ltd. 36 parts Methyl benzoate 54 parts TiO ₂ fine powder 7 parts Aerosil 380 (Japan Aerosil Co., Ltd.) 3 parts (Formation of SiO ₂ film) JP-A-55 −152 g of methyl orthosilicate, 240 g of glacial acetic acid, and methyl alcohol based on the method of 34258.
A mixture of methyl acetate, methyl alcohol, and hydroxysilane obtained by adding 10 g of oxalic acid to a mixture of 128 g and hydroxysilane was diluted with ethyl alcohol to a solid concentration of 5.0% by weight. The ink having the above composition was screen printed on the substrate, dried and cured at 120°C for 15 minutes, the coating solution was applied by dip coating at a pulling speed of 30 cm/min, and the film was prebaked at 140°C for 10 minutes to harden the film. This was then subjected to sonic cleaning with trichlorethylene for 3 minutes to remove the ink area and the coating on the ink area to form a pattern. Further heat this to 500℃
After baking for 30 minutes, a SiO ₂ film with a thickness of approximately 800 Å was patterned.

[Brief explanation of drawings]

FIGS. 1 to 3 are explanatory diagrams showing the steps of the metal oxide film pattern forming method of the present invention.
Figure 1 shows a state in which paste ink is applied by screen printing to areas where a metal oxide film is not desired to be formed, and Figure 2 shows a metal oxide film formed after the paste ink in Figure 1 has been dried. The ink layer and the metal oxide film-forming agent on it are removed by contacting the ink layer and the metal oxide film-forming agent thereon with an organic solvent. This shows the state in which the metal oxide film remains on the substrate. The symbols in the drawings indicate the following. 1...
...Base, 2... Paste ink, 3... Layer of metal oxide film forming agent, 4... Metal oxide film, 5
... Kratsk.

Claims (1)

[Claims] 1 Mainly polymers insoluble in one or more alcoholic solvents selected from saturated polyester resins, cyclized rubber, homopolymers of acrylic esters or methacrylic esters, and copolymers of acrylic esters or methacrylic esters. After screen-printing the desired pattern on the substrate using a paste-like ink, a metal oxide film-forming agent containing alcohol as the main solvent is applied to the entire surface and heated at approximately 100 to 300℃. heat treatment at a high temperature, then use an organic solvent to dissolve and remove the above paste-like ink printed area and also remove the metal oxide film forming agent on the ink printed area, and then bake at a temperature of 150°C or higher. A method for forming a pattern of a metal oxide film, the method comprising forming a metal oxide film on a non-printing area.