JP2000258923A - Method of forming tin oxide conductive pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of forming a high precise pattern of conductive tin oxide having excellent wear resistance on the surface of a substrate by a wet etching method regardless of the size of the non-conductive substrate and without polluting the working environment in a roam. SOLUTION: The tin oxide conductive pattern is formed on the surface of the non-conductive substrate by forming successively a tin oxide conductive film and a photoresist resin film on the surface of the non-conductive substrate in layer and after forming the desired pattern on the resist resin film, applying a coating aq. paste containing fine powdery zinc and adjusted to have 3,000-50,000 cp viscosity on the surface by a screen printing, etching the coated surface to form the tin oxide conductive pattern and removing the remaining resist resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a conductive pattern of tin oxide on the surface of a non-conductive substrate such as a glass substrate or a silicon wafer. It relates to a method of forming well.

[0002]

2. Description of the Related Art Conventionally, a wet method and a dry method are known as typical etching techniques. The wet method is advantageous both industrially and in terms of operation, and the etching of a large glass substrate used as a non-conductive substrate is preferably performed by the wet method, which is extremely practical. In fact, a film of indium and tin oxide (ITO), which is widely used as a transparent conductive film, has different absolute values of the etching rates of the respective metal oxides contained therein. The conductive pattern is formed efficiently and industrially advantageously by a wet method in which an etching solution such as a combination with ferric chloride is used.

However, tin oxide has excellent chemical resistance, heat resistance, and high abrasion resistance. Until now, it has been difficult to obtain a high-precision tin oxide pattern with good reproducibility by etching with a wet method by photolithography. Was technically difficult. Moreover, the etching of the tin oxide film by the wet method requires an extremely high level of craftsmanship, and in fact, the etching treatment of the tin oxide film is performed only manually by a skilled person in a laboratory. Large pattern processing by the method is not currently performed. Thus, an industrially satisfactory etching method for forming a conductive fine pattern of tin oxide by a wet method has not yet been established. Therefore, the tin oxide pattern formation method is performed by a dry etching method using a lift-off method, which is cumbersome to operate, and industrially, plasma etching or reactive ion etching is performed on a substrate on which a photoresist negative pattern is formed. For example, a method of forming a tin oxide pattern by chemical vapor deposition is generally employed.

US Pat. No. 2,606,566 discloses a method of removing a tin oxide film formed on a glass substrate, for example, by using a powder of a metal that is more positive than tin such as zinc, cadmium, aluminum and iron. And a mixture containing water and a water-dispersible binder is coated on a tin oxide film, and then a non-oxidizing mineral acid such as hydrochloric acid, sulfuric acid, phosphoric acid or trichloroacetic acid is applied to the metal-coated substrate, and the electric power of the glass substrate is reduced. A method for reducing conductivity is described. The specification discloses that the mixture is directly applied to a glass substrate surface on which a transparent conductive tin oxide-containing coating is formed to reduce the conductivity of the entire surface or a limited area of the glass substrate, or that the tin oxide-containing coating is There is no description or suggestion of a high technique for overcoming the fine pattern uncut phenomenon in the formation of a fine pattern of tin oxide merely by teaching a macroscopic method of removing fine patterns.

[0005] In recent years, with the increase in size of a liquid crystal process (LCD) plasma display (PDP),
There is a demand for fine processing of a fine electrode circuit pattern on a large glass substrate. In the production of a fine pattern by wet etching of an ITO film or a tin oxide film on a large-sized substrate in accordance with such a social demand, uncut portions often occur, and particularly, a fine conductive pattern of tin oxide is industrially stabilized. There is a fatal problem that it cannot be formed on a surface such as a glass substrate. Therefore, at present, it is considered that forming a fine pattern of a tin oxide film on a large glass substrate by a lift-off method is difficult by a method other than dry etching.

The present inventors have conducted research on a wet etching method for a tin oxide film, and have found and proposed a method for forming a fine pattern of tin oxide using an industrially desirable etching aid liquid (Japanese Patent Application No. 2002-214,197). Hei 9-30212
No. 0). According to this method, the etching aid liquid is
A specific coating aqueous liquid containing powdered zinc, a water-soluble resin, and a silica-based inorganic fine particle material. This aqueous liquid is subjected to contact treatment on a substrate surface on which a resist resin pattern has been formed prior to etching with an acid. You. Since the unique aqueous auxiliary liquid for coating has a low viscosity, the surface of the tin oxide film substrate is immersed in the aqueous auxiliary liquid, sprayed with a liquid, or applied by a brush, a roller coat, a bar coat or the like. Is applied.

However, this coating means has various technical problems. For example, in the method of immersing the substrate in the aqueous auxiliary liquid, it is necessary to constantly stir and mix the liquid to keep the liquid homogeneous, and it is necessary to carefully and slowly lift the immersed substrate. Further, if the viscosity of the liquid is less than 5 centipoise, it is difficult to obtain a uniform coating film, and if the viscosity is more than 100 centipoise, the coating film becomes thicker, which is inconvenient. Although a good film is formed when the viscosity of the liquid is in the range of 10 to 50 centipoise, the immersion method is industrially disadvantageous because a coating film is formed on the side surface of the substrate, resulting in an increase in cost. This immersion method has no operational problem particularly when the diameter of the substrate is about 12 inches, but for example, for a substrate having a diameter of 40 inches or more, a uniform coating film is formed because the substrate is slightly bent by its own weight. Is difficult.

The coating method such as brush coating, roller coating and bar coating is not inconvenient for a substrate having a diameter of about 12 inches, but it is easy to form a uniform film by brush coating a substrate having a diameter of 40 inches or more. In order to achieve this, multiple coatings must be performed, so that the film thickness is inevitably increased, resulting in an increase in cost. Also, in the case of a roller coat or a wire bar coat, it is difficult to uniformly apply a substrate having a size of 40 inches or more due to deflection due to its own weight. The application method of spraying the aqueous liquid for coating enables uniform application regardless of the size of the substrate, but the application efficiency is only about 60%,
Approximately 40% becomes mist-like fine particles and scatters in the atmosphere, causing deterioration of the indoor environment.

[0009]

The present inventors have, in particular,
Various trials and researches were conducted on practically desirable improvement methods for overcoming the above-mentioned drawbacks related to the uniform application of the aqueous auxiliary liquid for coating. Therefore, an object of the present invention is to provide a wet etching method in which a coating aqueous auxiliary liquid is uniformly applied to a substrate surface on which a pattern of a photoresist resin is formed on a tin oxide conductive film, regardless of the size of the substrate. Another object of the present invention is to provide a practical method that does not pollute the indoor working environment. Another problem is that a non-conductive substrate on which a high-precision pattern of conductive tin oxide having excellent wear resistance is formed,
For example, it is to provide a glass substrate for a touch panel, a glass substrate for a PDP, a glass substrate for an amorphous solar cell, or the like in an industrially advantageous manner.

[0010]

According to the present invention, a fine and high-precision conductive pattern of tin oxide is easily and stably formed on the surface of a non-conductive substrate according to the requirements of claim 1. To provide an industrially advantageous practical method of forming In particular, the method of the present invention includes forming a conductive film of tin oxide on the surface of a non-conductive substrate, forming a desired pattern of a photoresist resin on the conductive film, and forming fine powdered zinc on the surface. There is a technical feature in patterning by a wet method in which an aqueous paste for coating adjusted to a specific high viscosity range containing is applied by screen printing and etched.

As described above, in the method of the present invention, prior to the etching of the conductive tin oxide film on the surface of the non-conductive substrate, fine powdered zinc is used as a pretreatment agent for efficiently performing the etching. Concentration and viscosity 3,000-50,0
A characteristic feature is that a specific coating aqueous paste adjusted to a range of 00 cp is applied to a desired region of the tin oxide film by screen printing, and is brought into close contact with the tin oxide film in advance. The high-viscosity aqueous paste ensures uniform coating even on large substrates with a diameter of 40 inches or more, and is printed in accordance with the desired defined area to be coated, so loss of pretreatment agents is greatly reduced. This has the advantage that the etching efficiency of the subsequent wet etching process can be increased.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION A non-conductive substrate on which a conductive pattern is formed in the method of the present invention is useful for forming a fine conductive pattern to be used for LCDs for TFTs, PDPs, touch panels, panels for solar cells, and the like. Non-conductive substrate materials capable of providing electronic components are included. Specific examples of such a substrate include, for example, glass, a silicon wafer, and a glass substrate for an amorphous solar cell.
In the method of the present invention, as a method of forming a tin oxide film on the surface of a non-conductive substrate, for example, tin oxide may be formed by any commonly known method such as electroplating, sputtering, ion plating or metal deposition. A method can also be adopted. The thickness of the formed film is usually from 30 nm to 1500
It is in the range of nm, and is appropriately selected depending on the size of the substrate, the application target, and the like.

Next, a photoresist resin solution is applied to the surface of the tin oxide conductive film and dried to form a resist layer (film). The dry film thickness of the photoresist resin may be a film as thin as possible as long as it can stably protect the tin oxide film covered with the resist resin film in the etching treatment with the etching solution. 1-2
A thickness of about μm is practical but not limited. As the resin for the photoresist, any of various conventionally known photocurable resins can be used. Typical examples of such resins include cresol-novolak resins, phenol-novolak resins, and substituted phenol-novolak resins.

Next, a photomask having a desired pattern is placed on the substrate on which the photoresist resin film is formed,
The resist film is irradiated with ultraviolet rays, plasma, or other suitable actinic rays through the mask, and then the resist film is developed and rinsed. A fine resist resin positive pattern is formed. The substrate on which the resin pattern is formed as described above generally improves adhesion and corrosion resistance to a conductive film and stabilizes the pattern.
It is baked at a temperature in the range of ° C.

In the present invention, prior to etching, an aqueous paste for coating whose viscosity has been adjusted to a specific viscosity range containing fine zinc powder is preliminarily etched on the substrate surface on which the resist resin pattern has been formed. Applied as a processing aid. The zinc powder used in the coating aqueous paste is practically a fine powder having a size of 10 μm or less, and a powder having a size of 5 μm or less is particularly preferable. Practically desirable zinc powder size is 0.1 ~
The range is 5 μm.

The concentration of the zinc powder contained in the aqueous paste can be applied in a wide range of 10 to 85% by weight. 30n when the content of zinc powder is less than 10% by weight
m tin oxide pattern may cause the uncut portion, and if it exceeds 85% by weight, the viscosity of the aqueous paste becomes too large and adversely affects the printing operation. The concentration of zinc powder in the aqueous paste for coating is:
In consideration of the uncut phenomenon in the etching, it is preferable to further select according to the thickness of the tin oxide film to be etched. Usually, the tin oxide film having a thickness of about 30 to 100 nm has a zinc powder-containing concentration. The range of 30 to 60% by weight is practical, and a high-concentration paste containing about 70 to 85% by weight of zinc is preferably used for etching a thick tin oxide film, for example, a tin oxide film having a thickness of 800 to 2000 nm. .

The aqueous paste used in the method of the present invention does not flow out of the screen-printed area and has good adhesion to the substrate surface, for example, 3,000 to 50,000 cp. The viscosity is adjusted to Such a degree adjustment is generally performed by adding an additive to a liquid containing a desired amount of zinc powder. Such additives include, for example, thickeners, water-soluble resins, silica-based and other finely divided inorganic materials, and surfactants. Also, a small amount of other additives that do not adversely affect the screen printing and the etching of the tin oxide film can be added. If the viscosity of the paste is less than 3,000 cp, uniform screen printing becomes difficult due to the low viscosity, and the ink flows out of the substrate surface after printing, resulting in a loss, which is industrially disadvantageous. On the other hand, if it exceeds 50,000 cp, the printing workability is remarkably reduced due to too high viscosity, which is disadvantageous. Practically desirable aqueous zinc-containing aqueous pastes have a viscosity of 5,000 to 40,000 cp, in particular 10,000 to
30,000 cp is preferred.

Examples of the thickener used as an additive in the coating aqueous liquid include bentonite, silica gel, starch and the like. The water-soluble resin includes water-soluble or self-dispersible thermoplastic resins having strong water affinity. Examples of such a resin include sodium carboxymethylcellulose, methylcellulose, sodium polyacrylsan, gum arabic, guar gum, taracant gum, and the like. Pectin and locust bean gum. These water-soluble resins are usually used in an amount of 0.1 to 10% by weight based on the coating liquid. Further, typical examples of the silica-based inorganic material added to the coating liquid include kaolin, diatomaceous earth, colloidal silica, silica gel, talc, perlite, bentonite, and the like. The addition amount of these silica-based inorganic materials is usually 0.1 to 10% by weight based on the coating solution.
It is about.

In the method of the present invention, a hydrophilic organic solvent or a surfactant can be further added to the aqueous solution for coating, if necessary. Examples of the hydrophilic organic solvent include methanol, ethanol, isopropyl alcohol, ethylene glycol, propylene glycol, glycerin, and sugar alcohol. These organic solvents may be used alone or in combination of two or more. The addition amount is, for example, 0.
The concentration ranges from 1 to 10% by weight.

As the surfactant, a nonionic surfactant and an anionic surfactant are used. Nonionic surfactants include, for example, alkyl phenol (alkyl group having 6 to 14 carbon atoms) alkylene oxide (alkylene has 2 to 4 carbon atoms) adduct (addition mole number is usually 4 to 30). Alkylene oxide adduct of higher alcohol (12 to 22 carbon atoms) (addition mole number, usually about 4 to 30), perfluoroalkyl (alkyl group has 6 to 14 carbon atoms) sulfonamide alcohol And alkylene oxide adducts of N- (perfluoroacyl) -alkylenediamine and the like. As the anionic surfactant, any of those generally known can be used,
Perfluoroalkyl (alkyl group having 8 to 1 carbon atoms)
4) Sulfonic acid alkali metal salts are preferably used. These surfactants may be used alone or in combination of two or more.

Among these surfactants, preferred are alkylene oxide adducts of alkyl phenols,
Perfluoroalkyl sulfonates and alkylene oxide adducts of perfluoroalkyl sulfonamide alcohols, particularly preferred are 10 moles of ethylene oxide of nonylphenol, 10 moles of ethylene oxide of dodecylphenol and propylene oxide 2
A molar adduct, a potassium salt of perfluorodecyl sulfonate and a 20 mol adduct of ethylene oxide with perfluorooctylsulfonamide ethanol. In the method of the present invention, the surfactant to be present in the aqueous liquid for coating is usually 0.5% based on the aqueous paste.
A small amount of not more than 0.0005 to 0.25% by weight.
A range of weight% is preferred. The addition of a small amount of surfactant
This is preferable because the rate of uncut portions of the conductive pattern in the etching process is reduced and the accuracy of pattern formation is improved.

The aqueous paste for etching pretreatment whose viscosity has been adjusted is usually applied by printing with a squeegee through a screen in which a printing area capable of printing on the substrate surface on which the tin oxide film and the photoresist resin pattern are formed is formed. You. As the screen used for screen printing in the method of the present invention, for example, a screen having a mesh of about 100 to 400 mesh is suitably used. The selection of the screen mainly takes into consideration the thickness of the tin oxide film on the substrate surface to be etched, and also relates to the size and the concentration of zinc powder in the paste and the desired coating amount per unit area. Selected. In this screen printing, since the viscosity of the zinc dust-containing paste is high, there is substantially no possibility that the paste will flow out of the applied region in a protruding state, and it is possible to conveniently cope with the case where the application region is limited. Since it is possible, it is industrially extremely desirable in terms of operability and also in that the loss of the paste can be kept small.

The contact time of the printed aqueous paste with the tin oxide film varies somewhat depending on the thickness of the tin oxide film to be etched, the zinc concentration of the paste and the fluidity (viscosity).
Long hours are not required. For example, it is effective even for a short time of 1 minute or less, and usually, a contact time of about 1 to 10 minutes is preferably employed, but the optimum time can be easily determined by a simple experiment. The substrate on which the paste is printed is then etched. The tin oxide film in contact with the zinc powder-containing paste is very efficiently etched away by etching solution treatment, and is dissolved leaving the resist resin pattern portion. According to the wet method of the present invention, inconvenient phenomena such as uncut parts, which were unavoidable in the conventional wet method, are effectively eliminated, and the tin oxide pattern is extremely easily and highly accurately formed on the surface of the non-conductive substrate. It is formed. The reason why the excellent etching effect is obtained is not clear, but it is presumed that the preliminary treatment by screen printing of the aqueous paste containing high-concentration zinc fine powder works extremely effectively.

As the etchant used for the above-mentioned etching treatment, various acid etchants used for conventional metal etching can be conveniently used. Examples of such an etchant include sulfuric acid, nitric acid, phosphoric acid, hydrofluoric acid, oxalic acid, acetic acid, hydroiodic acid, trichloroacetic acid, aqua regia, ferric chloride and hydrochloric acid solution, hydrochloric acid and nitric acid, sulfuric acid and hydrochloric acid, and phosphoric acid And acid liquids such as nitric acid, phosphoric acid and hydrochloric acid, and hydrogen peroxide and sulfuric acid. Usually, these acid solutions are prepared and used in an aqueous solution having an appropriate concentration for the acid. These etchants may be applied by spraying or the like, or the substrate may be immersed in the etchant. In the immersion treatment, for example, after the liquid is kept at a temperature of 10 to 40 ° C. and immersed therein for about 30 to 60 seconds, the substrate is washed with water. Instead of the immersion treatment, the nonwoven fabric impregnated with the etching solution may be pressed against the printed surface of the paste to perform the etching treatment.

The substrate thus etched is:
Finally, the resist resin layer remaining on the pattern surface layer is removed. The removal treatment is easily performed by contacting and dissolving in a suitable solvent capable of dissolving the photocurable resist resin. In this way, even in the case of a large-sized substrate, a non-conductive substrate on which an extremely high-precision tin oxide conductive pattern having no uncut portions can be industrially advantageously obtained. The solvent for dissolving the resist resin varies depending on the type of the photocurable resist resin, and examples thereof include an organic solvent such as acetone, methyl-ethylketone, and dimethylformamide, an alkaline aqueous solution, and warm water. As these solvents, those which do not harm the tin oxide pattern and are suitable for dissolving the resist resin used are selected and used.

[0026]

Next, the features of the present invention will be described in more detail with reference to specific examples. In addition, the number of parts and% in the examples are by weight unless otherwise specified. In the evaluation of the etching performance in each specific example, the tin oxide pattern formed on the glass surface was observed with a microscope, and the ratio of the uncut area to the total area was indicated as the uncut rate (defective rate)%.

Example 1 A thin tin oxide film having a thickness of 30 nm was formed on one surface of a 3 inch square glass substrate by sputtering, and then this was washed with a glass substrate cleaning agent (Yokohama Yushi Kogyo Co., Ltd.). (Product name: Semi-clean KG) and dried. Photoresist photosensitive solution [trade name: OFPR-800 (35 cp) manufactured by Tokyo Ohka Kogyo Co., Ltd.] on the tin oxide film
Was spin-coated at 3,000 rpm for 3 seconds using MIKASA SPINNER IX-DX (manufactured by Mikasa Corporation). Each of the coated photoresist resin films was prebaked at a temperature of 80 ° C. for 30 minutes using a warm air dryer.

Next, in order to check the pattern formation accuracy,
The test pattern line thickness is 2 μm, 5 μm, 10 μm,
Using various photomasks of 20 μm, 30 μm, and 40 μm, light irradiation was performed using a mask alignment device (manufactured by Mikasa Corporation) to form a resist resin pattern for each mask. The light irradiation was performed by irradiating each with actinic radiation for 5 seconds. This was developed at room temperature for 60 seconds by immersion rocking method using a developing solution NMD-3 (manufactured by Tokyo Ohka Kogyo Co., Ltd.). Immediately rinse the developed substrate surface with pure water for 60 seconds, then wash with a pure water shower for 5 seconds, and post-bake for 30 seconds to obtain various types of glass on which the negative resist pattern of each photomask was formed. A substrate was obtained. A 180-mesh SN-silk screen (manufactured by Shin Nihon Zokei Co., Ltd.) made of Tetron is placed on the glass substrate surface on which the resist resin pattern is formed, and about 0.5 g of a 10,000 cp viscosity aqueous paste having the following composition is passed through the screen.
Was applied by printing with a squeegee.

(Aqueous paste) (%) Zinc powder 20 Methyl cellulose 2 Silica gel 30 Propylene glycol 0.5 Ethylene oxide 12 mol adduct of lauryl alcohol 0.1 Water 47.4

Next, the coated substrate is reduced to 10%
After being immersed in an aqueous hydrochloric acid solution at room temperature for 60 seconds to perform etching treatment, taken out and sufficiently washed with water, the remaining resist resin was dissolved and removed with acetone. In addition, etching treatment was similarly performed using a 5% hydrochloric acid aqueous solution as an etching solution, and comparison was made. This operation was performed for test patterns of various line widths, and the uncut ratio (%) was examined for each of them. The results are shown in Table 1 below. As a pattern formation precision, a sharp fine line pattern with a line width of 10 μm and no uncut portion was formed on the glass substrate surface. (Table 1) Etching solution pattern Line width Hydrochloric acid concentration% 2 μm 5 μm 10 μm 20 μm 30 μm 40 μm 5 11 4 0 0 0 10 10 5 3 0 0 0 0 0

COMPARATIVE EXAMPLE 1 For comparison, a photomask for a test pattern having various line widths was formed on a photoresist resin film formed on a tin oxide film having a thickness of 30 nm in the same manner as in Example 1. Each of the 3-inch square glass substrates having been subjected to various resist patterning processes was similarly treated with a representative coating solution having the following composition described in U.S. Pat. No. 2,606,566 prior to etching. Deionized water 971.4 ml Glycerin 14 ml Sodium nitrite 2.8 g Sodium pyrophosphate 1.4 g Bentonite 6.9 g When using, 300 g of powdered zinc was added to 700 g of the above mixed solution to prepare and use a coating aqueous solution having a zinc content of 30%.

The aqueous coating solution thus prepared
0.5 g of a 5% or 10% hydrochloric acid aqueous solution is applied to a 3-inch square glass substrate on which a photoresist pattern has been applied, using the same screen as in Example 1 by screen printing. It was immersed for 60 seconds for etching. After sufficiently removing the removed glass substrate with water, the remaining resist resin was dissolved and removed with acetone to obtain a glass substrate for a touch panel having a tin oxide pattern. The percentage of uncut portion (defective rate) of tin oxide pattern substrates having various line widths obtained by the same treatment was measured by microscopic observation, and the results are shown in Table 2.

(Table 2) Etching solution pattern Line width Hydrochloric acid concentration% 2 μm 5 μm 10 μm 20 μm 30 μm 40 μm 5 56 45 34 21 10 5 10 60 22 18 15 5 3 Remaining pattern with a line width of 40 μm on the glass surface Was formed.

[Example 2] 80 nm in the same manner as in Example 1.
Is formed on the surface of a 3-inch square PDP glass substrate on which a photoresist film is patterned by a photomask of a test pattern having the same various line widths.
About 0.5 g of an aqueous paste having the following composition was applied by a screen printing method to form a dried coating film. (Aqueous paste) (%) Zinc powder 30 Sodium carboxymethylcellulose 3 Aerosil 2005 Kaolin 25 Isopropanol 0.5 Ethyl oxide 10 mol adduct of nonylphenol 0.1 Water 36.4

Next, the substrate on which the coating film was formed was immersed in an etching solution of a 5% hydrochloric acid aqueous solution and a 10% hydrochloric acid aqueous solution for 60 seconds. After thoroughly washing the treated substrate with water, the remaining resist resin was dissolved and removed with acetone. Table 3 below shows the percentage of uncut portions. (Table 3) Etching solution pattern Line width Hydrochloric acid concentration% 2 μm 5 μm 10 μm 20 μm 30 μm 40 μm 5 15 8 3 0 0 0 10 8 5 2 0 0 0 Sharp fine line pattern with 20 μm on the glass surface was gotten.

Example 3 As in Example 1, a 30-nm thick tin oxide film and a photoresist resin film were formed on one surface of a 3-inch square glass substrate. The respective photoresist patterns were formed using masks of different test patterns. 180 g of the aqueous paste for coating of the following composition
Screen printing was performed using a mesh screen and dried to obtain a dry coating film of the paste.

(Aqueous paste) (%) zinc powder 40 guar gum 3 thyricia 770 20 sorbitol 70 0.5 perfluorooctylsulfonamide ethylene oxide 20 mol adduct 0.1 water 36.4

The substrate on which the paste coating film was formed was immersed in an aqueous hydrochloric acid solution and subjected to an etching treatment at room temperature for 60 seconds. Etching was performed for two types in 5% and 10% hydrochloric acid aqueous solutions for comparison. This was taken out of the solution, washed sufficiently with water, and the remaining resist resin was dissolved and removed with acetone. Table 4 below shows the result of examining the percentage of uncut portion of the pattern formed on each substrate.

(Table 4) Etching solution pattern Line width Hydrochloric acid concentration% 2 μm 5 μm 10 μm 20 μm 30 μm 40 μm 5 5 300 0 0 0 10 3 1 0 0 0 Sharp that is not cut off even at 10 μm on the glass surface A highly accurate fine line pattern was obtained. In addition, by using this aqueous paste and treating the transparent conductive film of tin oxide formed by sputtering in the same manner in place of the ITO film on the glass substrate for the touch panel, a fine pattern of an excellent electrode circuit can be obtained. Was.

Example 4 A film having a thickness of about 30 n was formed on one surface of a 3-inch square glass substrate for TFT by sputtering.
m of tin oxide was formed. The substrate on which the tin oxide film is formed is washed with a cleaning agent: semi-clean LGL (a glass substrate cleaning agent manufactured by Yokohama Yushi Kogyo Co., Ltd.), dried and then processed in the same manner as in Example 1 to form a resist film and patterning. To obtain a desired resist resin pattern. An aqueous paste for coating having the following composition (viscosity of about 30,000 cp) is applied to the glass substrate surface on which the resist pattern is formed.
0.5 g was applied by a screen printing method and dried.

(Aqueous paste) (%) Zinc powder 60 Sodium polyacrylate 3 Bentonite 10 Propylene glycol 0.5 12 mol ethylene oxide adduct of lauryl alcohol 0.1 Water 26.4

The substrate on which the dried coating film was formed was immersed in an etching solution of a hydrochloric acid aqueous solution at room temperature for 60 seconds, taken out and sufficiently washed with water, and then the resist resin was dissolved and removed with acetone. Table 5 shows the percentage of uncut remaining percentage of the tin oxide pattern on the glass substrate in the same manner as in Example 3 using six types of test patterns and two types of aqueous hydrochloric acid solutions.

(Table 5) Etching solution pattern Line width Hydrochloric acid concentration% 2 μm 5 μm 10 μm 20 μm 30 μm 40 μm 5300 0 0 0 0 0 0 0 0 0 Sharp with no residue even at 5 μm on the glass surface A glass substrate having a fine pattern of tin oxide was obtained.

Example 5 The same operation as in Example 1 was performed.
An 800 nm-thick tin oxide film was formed on a 3-inch square glass substrate surface, and a photoresist pattern was formed thereon. The patterned glass substrate for an amorphous solar cell with a tin oxide film has a viscosity having the following composition:
0.5 g of a 15,000 cp aqueous paste was applied by a printing method and dried to form a dry coating film.

(Aqueous paste) (%) zinc powder 70 guar gum 3 bentonite 1 glycerin 0.5 dodecylphenol ethylene oxide 10 mol adduct 0.1 water 25.4

On the solar cell glass substrate on which the coating film was formed, each resist resin pattern was formed using test patterns of various line widths in the same manner as in Example 1, and a 5% and 10% hydrochloric acid aqueous solution was used. Each of the two types was etched to obtain a glass substrate on which a tin oxide pattern was formed. The percentage of uncut portion of the tin oxide pattern formed on each substrate was examined, and the results are shown in Table 6.

(Table 6) Etching solution pattern Line width Hydrochloric acid concentration% 2 μm 5 μm 10 μm 20 μm 30 μm 40 μm 5 10 4 0 0 0 0 0 0 10 4 0 0 0 0 0 A glass substrate for a solar cell with no sharp pattern was obtained.

[0048]

According to the method of the present invention, the etching of a tin oxide film, which has been conventionally performed by a dry method called a lift-off method, can be processed by a wet method. A sharp tin oxide conductive fine pattern without defects can be efficiently formed on the non-conductive substrate surface. Further, since the method of the present invention does not substantially pollute the indoor working environment, it can be continuously produced in a clean room, and a fine pattern can be easily formed regardless of the size of the substrate. It is suitable for conductive patterning of tin oxide on a large glass substrate for PDP, a glass substrate for TFT, a glass substrate for touch panel, a glass substrate for solar cell, and the like, and is also industrially extremely desirable because it is suitable for mass production.

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Claims (2)

[Claims] 1. A method according to claim 1, wherein a tin oxide conductive film is formed on the surface of the non-conductive substrate and a photoresist resin film is sequentially formed on the surface of the conductive film. After irradiating and developing to form a photoresist resin pattern, an aqueous paste for coating containing fine powdered zinc on the surface and having a viscosity adjusted in the range of 3,000 to 50,000 cp is applied by screen printing, Next, a method of forming a tin oxide conductive pattern on a non-conductive substrate surface, comprising etching the applied surface to form a tin oxide conductive pattern and removing a resist layer remaining on the pattern. 2. The viscosity of the aqueous paste for coating is adjusted by an additive selected from the group consisting of a thickener, a water-soluble resin, a hydrophilic organic solvent, a surfactant, and an inorganic fine powder material. The method described in.