JP2002241951A - Method for depositing electroless zinc oxide film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for depositing an electroless zinc oxide film which has high light transmissivity and low sheet resistance value, and can thickly be deposited. SOLUTION: A nonconducting substrate in which a catalytic layer is formed on the surface of base material is dipped into an electroless zinc oxide plating solution containing a boran based reducing agent, so that an electroless zinc oxide film is deposited. In this method, after the dipping of the substrate into the electroless zinc oxide plating solution containing a boran based reducing agent, the substrate is dipped into a Pd treatment solution obtained by blending water soluble Pd salt and a complexing agent, and is again dipped into the electroless zinc oxide plating solution containing a boran based reducing agent, so that the electroless zinc oxide film is deposited. The zinc oxide film having high light transmissivity and low sheet resistance value can thickly be deposited, and is particularly suitable, e.g. for a transparent electrode of a liquid crystal display or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a high light transmittance,
The present invention relates to a method for forming an electroless zinc oxide film, which has a low sheet resistance and can form a thick zinc oxide film.

[0002]

2. Description of the Related Art In recent years,
2. Description of the Related Art With the high integration of electronic component circuits due to miniaturization and high performance of mobile phones and notebook computers, electroless plating free of defects at the atomic level has become necessary. As a method for forming a circuit on a non-conductive substrate using an electroless plating technique, metal palladium is adsorbed on a plating object with a catalyst solution containing a palladium salt such as palladium chloride and hydrochloric acid, and then the electroless plating is performed. A plating method has been used. In this study, Honma et al. Reported that the particle size and the nuclear density of Pd nuclei greatly affected the initial deposition state of the electroless plating film [J. Electr
ochem. Soc. , 144.4123 (199
7)]. However, the conventional Pd nucleus has a large particle size and a low nucleus density of the adsorbed Pd nucleus. Since the layer contains many defects, electroless plating without defects in the initial deposition layer is desired instead.

At present, ITO films are mainly used as conductive articles such as transparent electrodes used in liquid crystal displays and plasma displays. Generally, the conductive article is patterned by etching. But IT
O films are hard and difficult to etch. Therefore, the use of zinc oxide films produced by a dry method such as a magnetron sputtering method as conductive articles has been studied, but zinc oxide films are generally used. It has been difficult to put it into practical use as a conductive article because it has the property of increasing its specific resistance value when left in air.

[0004] Further, in the case of manufacturing by a dry method such as a magnetron sputtering method or a molecular beam epitaxy method, a vacuum evacuation device and a gas introduction device for controlling a film formation atmosphere, a high frequency power supply and a substrate heating device for generating plasma, and the like. Large-scale equipment such as a drive unit is required, and because of badge processing, continuous processing cannot be performed, resulting in poor productivity.
The production cost was high. Furthermore, it has been difficult to uniformly form a film on a large-sized substrate or a substrate having a complicated shape.

[0005] The zinc oxide film has a feature that it can be easily etched. However, the above circumstances make it difficult to use the zinc oxide film, and there are zinc oxide films that can be prepared from an aqueous solution. Because of poor transparency and conductivity, the range of use was limited.

The present inventor has provided a substrate having a high-density Pd nucleus dispersion layer capable of providing a dense, high-density defect-free electroless plating film in order to meet the above-mentioned demands, A zinc oxide film and a method for producing the same, each having a controlled orientation that can sufficiently utilize the above-described properties, and having high conductivity and excellent transparency, and having a specific resistance value even when left in the air. We have proposed a conductive article using a zinc oxide film produced from an aqueous solution with little fluctuation, in particular, a transparent electrode, and a method for producing the same (Japanese Patent Application No. 2000-362895).

[0007] However, electroless zinc oxide plating
In some cases, saturation occurs at a film thickness of about 200 nm, and the sheet resistance value becomes about 1 kΩ / □. This is presumed to be because electroless zinc oxide plating has no autocatalytic property.

The present invention has been made in view of the above circumstances, and provides a method of forming an electroless zinc oxide film having high light transmittance, low sheet resistance, and capable of forming a thick zinc oxide film. The purpose is to:

[0009]

Means for Solving the Problems and Embodiments of the Invention The present inventor has developed a method in which a substrate having a catalyst layer formed on the surface of a non-conductive substrate is converted into an electroless zinc oxide plating solution containing a borane-based reducing agent. In forming a new electroless zinc oxide film by immersion, as a new step, after immersing the substrate in an electroless zinc oxide plating solution containing a borane-based reducing agent, a water-soluble Pd salt and a complexing agent are mixed. The operation of immersing in the formulated Pd treatment solution and immersing it again in the electroless zinc oxide plating solution containing a borane-based reducing agent is repeated one or more times to form an electroless zinc oxide film. The present inventors have found that a film can be formed to be thick, have excellent light transmittance, and have a low sheet resistance value, and have accomplished the present invention.

That is, the present invention provides the following electroless zinc oxide skin
A method for forming a film is provided. Claim 1: a group in which a catalyst layer is formed on the surface of a non-conductive substrate
Electroless zinc oxide plating solution containing borane-based reducing agent
To form an electroless zinc oxide film by immersion in
Thus, the substrate is made of an electroless oxide containing a borane-based reducing agent.
After immersion in a lead plating solution, a water-soluble Pd salt and a complexing agent are distributed.
Immersed in the combined Pd treatment solution, and again
Electroless oxidation by immersion in the contained electroless zinc oxide plating solution
Electroless zinc oxide skin characterized by forming a zinc film
Method of forming a film. In a preferred embodiment, the concentration of the water-soluble Pd salt in the Pd treatment liquid is 8 × 1.
0^-Four~ 4.5 × 10^-2mol / L.
A method for forming an electroless zinc oxide film. Claim 3: Molar concentration ratio of water-soluble Pd salt and complexing agent (water-soluble
(Pd salt: complexing agent) is 1:10 to 1: 5000.
3. The method for forming an electroless zinc oxide film according to claim 1 or 2. Claim 4: The Pd treatment solution has a pH of 2 to 4.
3. The method for forming an electroless zinc oxide film according to any one of 3.
Law. In a preferred embodiment, the complexing agent is chloride.
The method for forming an electroless zinc oxide film according to claim 1. In another embodiment, the substrate on which the catalyst layer is formed is a non-conductive group.
On the material surface, Sn, Ag, and Pd are converted to Sn: Ag: Pd =
(1-10): (1-10): weight ratio of (1-10)
A high-density Pd nucleus dispersion layer having a catalyst layer
The substrate according to any one of claims 1 to 5, wherein the substrate has
A method for forming an electrolytic zinc oxide film. In a preferred embodiment, the catalyst layer is made of Sn, Ag, Pd.
1500 nuclei / μm ^TwoClaims with the above nuclear density
7. Formation of the electroless zinc oxide film according to any one of 1 to 6.
Method. Claim 8: The average roughness of the catalyst layer is 0.5 nm or less.
The electroless zinc oxide skin according to any one of claims 1 to 7.
Method of forming a film. Claim 9: The particle size of the catalyst core of the catalyst layer is 2 nm or less.
The electroless oxidation according to any one of claims 1 to 8, which is below.
How to form a zinc film.

Hereinafter, the present invention will be described in more detail.
In the method for forming an electroless zinc oxide film of the present invention, first, a catalyst layer is formed on the surface of a non-conductive substrate.

In this case, examples of the base material include non-conductive base materials such as glass, plastic, and ceramics, and may be a composite of these base materials. You can use what is.
In addition, a substrate in which an insulating material such as an oxide is coated on the surface of the base material can be employed. In addition, the shape may be plate-like, sheet-like, powdery, or the like, and is not limited. After washing these base materials with a known degreasing agent, an organic solvent, or the like, a known surfactant such as a surfactant or a silane coupling agent may be used. After applying a charge to the surface of the substrate using the surface conditioner, a catalyst applying treatment is performed.

[0013] The method of applying the catalyst on the non-conductive substrate includes a sensitizing-activating method,
An application method using an aqueous solution such as an alkali catalyst method or a catalyst-accelerator method, a method of applying an organic metal complex and then performing thermal decomposition, and a dry method such as a sputtering method can be used. In particular, in order to obtain light transmittance, it is preferable to form a catalyst layer having Sn, Ag, and Pd, and a method of imparting by sensitizing-silver activity-palladium activity using an aqueous solution involves the steps, aqueous solution, and treatment. It can be easily applied by controlling the conditions. For example, as a sensitizing solution, SnCl
₂ , 1 to 50 g / L of divalent tin ions in which a divalent tin salt such as SnSO ₄ is dissolved in an acid solution such as hydrochloric acid or sulfuric acid;
Use a strongly acidic solution of about H.
The immersion treatment is carried out at 0 to 60 ° C. for 10 seconds to 5 minutes.
1 to 0.5 mol / L, and the pH is 5 to 1
1, the liquid temperature may be 15 to 60 ° C., and the immersion treatment may be performed for 10 seconds to 5 minutes. As an activator containing palladium, a divalent palladium salt such as PdCl ₂ or PdSO ₄ is dissolved in an acid solution such as hydrochloric acid or sulfuric acid, and contains 0.01 to 1 g / L of divalent Pd ions; It is preferable to use a solution having a pH of 1 to 3 and perform immersion treatment at 10 to 60 ° C. for 1 second to 5 minutes. If soaked for a long time, Pd nuclei will aggregate,
Agglomeration may occur.

In the present invention, Sn, Ag, and Pd are particularly deposited on the surface of the non-conductive substrate, and Sn: Ag: Pd
= (1 to 10): (1 to 10): It is recommended to apply at a weight ratio of (1 to 10). In particular, in the case of an application method using an aqueous solution, in order to obtain fine catalyst nuclei at a high density, Preferably, Sn: Ag: Pd = (1-5) :( 1-5):
(1-5), more preferably Sn: Ag: Pd = (1-5)
4): (1-3): within the range of (1-2), and Sn
It is preferable that ≧ Ag ≧ Pd.

By giving Sn: Ag = about 3: 2 by the sensitizing treatment and the Ag activating treatment,
Fine catalyst nuclei can be provided at a high density.

Also, as for the ratio of Pd to be subsequently applied, it is particularly preferable that the ratio of Pd is smaller than that of Ag, and it is preferable that Ag: Pd = about 2: 1. The particle size tends to increase. If the amount of Pd is too small, the function as a catalyst for electroless plating deteriorates.

Around Sn: Ag: Pd = 3: 2: 1 is the optimum condition for obtaining fine catalyst nuclei at high density.

Here, in order to achieve the above-mentioned optimum conditions, it is particularly preferable to repeat sensitizing-silver activity-palladium activity as one step a plurality of times. Can be granted. Although the reason for this is not clear, a very fine catalyst nucleus is formed by performing the sensitizing-silver activity-palladium activity once, and the catalyst nucleus initially provided is obtained by repeating the above steps. This is presumably because catalyst nuclei are formed at a high density around the center.

When Sn, Ag, and Pd are within the above ranges,
From the catalyst core particles of 1500 nuclei / μm^TwoAbove, preferably
Is 2000 nuclei / μm^TwoAbove, more preferably 2500 nuclei
/ Μm ^TwoAbove, especially 3000 nuclei / μm^TwoWith the above nuclear density
can do. In this case, the high-density Pd nucleus dispersion layer
The average surface roughness is 0.5 nm or less, especially 0.3 nm or less
The catalyst core particle diameter is 2 nm or less,
Preferably 1.5 nm or less, more preferably 1 nm or less.
And a dense and dense layer can be formed. What
This high-density Pd nucleus dispersion layer is used as a catalyst layer for electroless plating.
In the case where the catalyst nucleus is used, the particle diameter of the catalyst nucleus is set to 0.1.
It is preferably at least 03 nm. Nuclear density above, average
Roughness and average particle size are determined by AFM (atomic force microscope) observation.
More measurable.

The weight ratio of Sn, Ag, and Pd is I
It can be analyzed by CP (Inductively Coupled Plasma Emission Spectroscopy).

In the present invention, the substrate having the catalyst layer formed on the surface of the non-conductive substrate is immersed in an electroless zinc oxide plating solution containing a borane-based reducing agent to form an electroless zinc oxide film. In this case, the substrate is immersed in an electroless zinc oxide plating solution containing a borane-based reducing agent, and then mixed with a water-soluble Pd salt and a complexing agent.
d. The film is dipped in the treatment liquid and dipped again in the electroless zinc oxide plating solution containing a borane-based reducing agent to form an electroless zinc oxide film.

Here, the electroless zinc oxide film deposition solution is not particularly limited as long as it is a solution for precipitating zinc oxide.
ol / L, preferably 0.05 to 0.2 mol / L,
An amine borane-based reducing agent such as dimethylamine borane or another reducing agent is used in an amount of 0.001 to 0.5 mol / L, preferably 0.0005 to 0.3 mol / L, particularly 0.0001.
PH of about 4 to 9 containing 0.2 mol / L, especially pH
A processing solution of about 6.5 can be suitably used.
At 80 ° C for 10 to 200 minutes, especially at 50 to 80 ° C for 30 minutes
A method of immersion treatment for up to 60 minutes can be adopted.

Here, the electroless zinc oxide film formed on the catalyst layer can be formed by changing the concentration of a borane-based reducing agent, particularly dimethylamine borane (DMAB), to change the crystal orientation of the electroless zinc oxide film [( 100) plane: (002)
Plane: (101) plane] can be controlled.

That is, for example, zinc nitrate 0.1 mol /
L, plating bath pH 6.3, plating bath temperature 68 ° C., DMAB concentration 0.001 to 0.01 mol / L
When adjusted to (101) plane, a zinc oxide film preferentially oriented was obtained, and when adjusted to 0.02 to 0.08 mol / L, a zinc oxide film oriented to (002) plane was obtained.
When adjusted to 0.2 mol / L, a zinc oxide film oriented on the (100) plane can be obtained. In particular, (002)
In the zinc oxide film preferentially oriented on the plane, the peak intensity ratio of the (002) plane is 1.5 times or more, especially 2 times or more, and more preferably 5 times or more of the peak intensity ratio of the (101) plane. An oriented zinc oxide film is obtained.

Here, the <preferred orientation> means (100) plane, (002) plane and (10) plane of zinc oxide as a result of X-ray diffraction.
1) The surfaces are compared and defined as having the largest peak intensity.

The orientation has a relation to each property of the electroless zinc oxide film, such as light transmittance, photocatalytic property, and conductivity. Under the above conditions of the electroless zinc oxide plating solution, the light transmittance is 90% or more. If so, the DMAB concentration is 0.001
0.1 mol / L, especially 0.005 to 0.05 mol
/ L (the peak is 0.03 mol / L), and in order to obtain high photocatalytic property, the DMAB concentration is set to 0.001 to 0.5 mol / L.
L, especially 0.01 to 0.3 mol / L (peak is 0.1
mol / L), to obtain the properties as a conductive film, use DM
The AB concentration is 0.001 to 0.05 mol / L, especially 0.1 to 0.05 mol / L.
005 to 0.03 mol / L (peak is 0.01 mol
/ L), the characteristics of these electroless zinc oxide films can be obtained. In addition, by considering this range, it is possible to easily obtain an electroless zinc oxide film having two or more of the above properties, for example, as a light-transmitting and conductive film such as a transparent conductive film. When the characteristics of both are utilized, the DMAB concentration is set to 0.005 to 0.05 mol /
L (eg, 0.01 mol / L),
A transparent conductive film having a light transmittance of 90% or more can be obtained. Thus, by setting the DMAB concentration, it is possible to obtain desired characteristics of the electroless zinc oxide film.

In the method for forming an electroless zinc oxide film of the present invention, the substrate on which the zinc oxide film is formed is treated with a water-soluble Pd
Immersed in a Pd treatment solution containing a salt and a complexing agent,
Adsorption and then electroless zinc oxide plating
It is repeated one or more times.

Here, the Pd treatment liquid of the present invention is a water-soluble Pd
It can be obtained by dissolving the d salt and the complexing agent in an acid solution such as hydrochloric acid and sulfuric acid.

The water-soluble Pd salt includes, for example, P
dCl _2, mention may be made of PdSO _4, etc., as the complexing agent, potassium chloride, water-soluble alkali metal salts such as sodium chloride, alkaline earth metal salts such as magnesium chloride,
Examples include aqueous ammonia, ammonium compounds such as ammonium chloride, carboxylic acids such as citric acid and malic acid, and water-soluble salts thereof, among which chlorides are preferred.

In the present invention, the molar concentration ratio of the water-soluble Pd salt to the complexing agent (water-soluble Pd salt: complexing agent) is usually from 1:10 to 1: 5000, especially from 1:30 to 600. It is recommended that If the molar concentration ratio of the complexing agent to the water-soluble Pd salt is less than 10, the surface roughness of the zinc oxide film formed in the next step becomes rough, and the amount of Pd adsorbed increases, so that the light transmittance decreases. , And turns black. On the other hand, 500
If it is more than 0, the amount of adsorption of Pd decreases, and it may be difficult to further deposit zinc oxide.

In the Pd-treated solution of the present invention, the water-soluble Pd salt contains 8 × 10 ^{−4 to} 4.5 × 10 ⁻² mol / L, particularly 8 × 1 ⁻⁴ mol / L.
It is recommended that the compounding be performed so as to be 0 ^-4 to 1 × 10 ^-2 mol / L. If the amount is small, the amount of Pd adsorbed is small, and the deposition of the zinc oxide film is difficult.
The adsorption amount of d increases, and the light transmittance deteriorates.

It is recommended that the pH of the Pd treatment liquid of the present invention be adjusted to 2 to 4, especially 2.5 to 4. If the pH is too low, the electroless zinc oxide film may be excessively dissolved by the strong acid. Although the reason is not clear on the zinc oxide film, if the concentration of the water-soluble Pd salt is too high, the Pd nucleus tends to agglomerate. However, fine Pd nuclei can be adsorbed by setting the concentration of the complexing agent within the above range. However, if Pd is complexed only with an acid such as hydrochloric acid, the pH may be too low, eroding the zinc oxide film and roughening the surface. Therefore, it is further necessary to keep the pH within the above range. If fine Pd nuclei are dispersed and the surface is dense, the electroless zinc oxide film to be subsequently deposited can also have excellent light transmittance with low surface roughness.

In the present invention, in the immersion step in the Pd treatment liquid, the substrate on which the zinc oxide film is formed is immersed in the Pd treatment liquid containing the water-soluble Pd salt and the complexing agent. However, the processing time is usually 15 seconds to 5 minutes, especially 15 minutes.
Seconds to 1 minute, processing temperature room temperature to 80 ° C, especially 25 to 6
It can be performed under the condition of 0 ° C.

In the method for forming a zinc oxide film of the present invention, the above-mentioned Pd treatment solution immersion treatment and the subsequent electroless zinc oxide plating treatment can be performed one or more times, usually 1 to 10 times. If used, it can be repeated 2-5 times.

In the electroless zinc oxide plating, the maximum deposition rate is at the beginning of the plating, and the deposition rate is gradually decreased. Thickness can be obtained.

The electroless zinc oxide plating after the Pd treatment liquid immersion step can be performed under the same method and conditions as described above.

In this case, in order to obtain light transmittance,
The thickness of each zinc oxide film in each electroless zinc oxide plating step is 0.005 μm or more, preferably 0.05 μm or more.
However, the total thickness of the zinc oxide film can be 0.2 to 2 μm, particularly 0.4 to 1 μm, but is not limited thereto. In order to obtain a film having a low sheet resistance value at the expense of light transmittance, the thickness can be further increased.

Further, an electrolytic zinc oxide film may be formed on the electroless zinc oxide film from the above-mentioned composition using the electroless zinc oxide film as a cathode.

In this case, the electrolytic zinc oxide film deposition solution is not particularly limited as long as it is a liquid for precipitating zinc oxide, and a zinc salt such as zinc nitrate 0.01 to 0.5 mol is used.
1 / L, preferably a treatment solution having a pH of about 4 to 9, particularly pH 6 containing 0.05 to 0.2 mol / L, and a conductive substrate using zinc, carbon, platinum or the like as an anode. 0.1-20 coulombs per cm ² ,
Preferably, a current of 1 to 10 coulombs is applied to obtain a zinc oxide film. The bath temperature is used in the range of 10 to 80C.

In the present invention, the zinc oxide film is
If necessary, it can be modified by a modifier,
Heat treatment can be performed.

In this case, a modifying agent for modifying the zinc oxide film
Is preferably an aqueous solution containing a trivalent metal cation.
Here, the trivalent metal cation is In³⁺,
Al ³⁺, Ga³⁺, Tb³⁺, Y³⁺, Eu³⁺, Bi³⁺, Ru
³⁺, Ce³⁺And one of these or 2
Contains more than one species. In addition, as a counter anion
Can be used as an aqueous solution of the trivalent metal compound.
Well, although not particularly limited, sulfate ion, halogen ion
, Phosphate ion, nitrate ion, acetate ion, citric acid
Ions, lactate ions and other carboxylate ions
No. The trivalent metal cation is contained in an aqueous solution.
0.1 to 50 g / L, more preferably 0.3 to 3 g / L
It is effective to be contained. The above trivalent metal cation
Is out of the above range, a modified film is uniformly formed on the zinc oxide.
There is a possibility that it cannot be obtained.

The pH of the trivalent metal cation-containing aqueous solution (modifier) is preferably 2 to 10, more preferably 3 to 8.

The content of the trivalent metal in the zinc oxide film obtained by the above treatment is preferably 0.01% by weight or more in order to stabilize the specific resistance value, and further excellent transparency is obtained. For this purpose, the content is preferably 30% by weight or less. More preferably, it is 0.05 to 10% by weight, further preferably 0.1 to 5% by weight.

The conditions for treating the zinc oxide film with the modifying agent are appropriately selected, but are preferably 10 to 60 ° C., particularly 20 to 4 ° C.
A condition of about 1 second to 10 minutes at 0 ° C. can be adopted,
The treatment can be carried out by immersing zinc oxide in a modifier, but may be carried out by a spray treatment or the like.

According to the above treatment, since the surface of the zinc oxide film is wet with the aqueous solution, the contact with the air can be suppressed. Therefore, it is possible to suppress the fluctuation of the resistivity of the zinc oxide film during the treatment. Can be.

The conditions for heat-treating the modified zinc oxide film obtained in the above step are as follows.
C., preferably at 200 to 650 ° C., and the heating time is preferably 5 minutes to 2 hours, whereby the conductivity is further improved.

Here, the above-mentioned heat treatment can be carried out after the above-mentioned modification treatment, but may be carried out after a layer other than the zinc oxide film described later is formed on the zinc oxide film.

Further, the heating atmosphere may be any of the atmosphere, a non-oxidizing gas atmosphere such as nitrogen, helium, and argon, a reducing gas atmosphere such as hydrogen, and a mixed gas atmosphere thereof. Is preferably 100 ppm or less, particularly preferably 10 ppm or less. If the oxygen concentration in the gas atmosphere is higher than 100 ppm, the conductivity may not be sufficiently improved even when heated. This is considered to be because it is difficult to form oxygen defects in the zinc oxide film due to a large amount of oxygen in the gas atmosphere. Further, a reducing gas such as hydrogen is introduced into a non-oxidizing gas atmosphere at 0.0
By using a mixed gas containing 1 to 10% by volume, particularly 0.05 to 5% by volume, a zinc oxide film having a lower resistance value can be obtained. This is presumably because oxygen gas defects are formed in the zinc oxide film by the reducing gas, and a zinc oxide film having a low resistance value is obtained. Also, part of zinc oxide may be reduced to metal by the reducing gas.

The modified zinc oxide film produced by the process of the present invention has a sheet resistance of 500 Ω / □ or less, particularly 350 Ω / □ or less, and has good conductivity, and can be used as an electrode. Further, using the modified zinc oxide film as a cathode, various layers can be formed on the zinc oxide film, for example, a metal layer or an electrodeposition coating layer can be formed. In this case, the zinc oxide film is easily etched (it can be easily etched without using a strong acid solution or a strong alkali solution), so that a metal or the like which is difficult to etch can be easily patterned. Since the pH of the solution for forming the zinc oxide film is also near neutrality, the treatment can be performed without eroding the substrate. In addition, when performing electrodeposition coating, electrodeposition coating on a non-conductive material becomes possible,
When a zinc oxide film with transparency is made,
It is possible to suppress the color tone change of the electrodeposition coating film when the film thickness of the electrodeposition coating film is small, which is caused by the uneven color of the metal layer serving as the cathode, and it is also possible to obtain a patterned electrodeposition coating if necessary. it can.

Also, it can be used as a photocatalyst film.

[0051]

According to the method for forming an electroless zinc oxide film of the present invention, the light transmittance is high, the sheet resistance is low, and a thick zinc oxide film can be formed. It is suitable for electrodes and the like.

[0052]

EXAMPLES The present invention will be described below in detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

Examples 1 to 18, Comparative Example Using soda lime glass as a non-conductive substrate, a film was formed on a substrate provided with a catalyst in the following steps.

(1) Addition of catalyst i. Degreasing / Surface Adjustment A immersion treatment was performed at 50 ° C. for 5 minutes in the following surface conditioner solution. Asahi Cleaner C-4000 <made by Uemura Kogyo Co., Ltd.>
5 g / L ii. Washing at 25 ° C for 15 seconds iii. Sensitizing It was immersed in the following sensitizing solution at 20 ° C. for 1 minute. Tin chloride 15 g / L hydrochloric acid 45 mL / L pH 0.5 iv. Rinse at 25 ° C for 15 seconds v. Catalyst application Immersion in the following silver activation solution at 20 ° C. for 1 minute. Silver nitrate 3 g / L pH 7.0 vi. Water wash 25 ° C, 15 seconds vii. Catalyst application Immersion in the following palladium activation solution at 20 ° C. for 1 minute. Palladium chloride 1.5 g / L Hydrochloric acid 1.5 mL / L pH 2.8 viii. Washing with water 25 ° C., 15 seconds The operations iii to viii were repeated three times. The high-density Pd nucleus dispersion layer obtained above was as shown in Table 1 below.

[0055]

[Table 1]

(2) Electroless ZnO Plating The substrate provided with the above catalyst was immersed in the following electroless ZnO plating solution at pH 6.3 and 68 ° C. for an immersion time shown in Table 3. Zinc nitrate 0.1 mol / L DMAB 0.03 mol / L pH 6.3

(3) Pd adsorption A solution obtained by adding KCl in an amount shown in Table 3 to a treatment solution having an A-10X concentration shown in Table 2 was immersed in the immersion time shown in Table 3.

(4) Operation similar to electroless ZnO plating (2) The operations (3) and (4) were repeated the number of times shown in Table 3.

(5) The immersion treatment was performed for 15 seconds in a treatment solution of In substitution or less. Indium sulfate 1 g / L pH 4

(6) Drying was performed for 10 minutes at 500 ° C. in a mixed gas atmosphere of heated hydrogen 3% and nitrogen 97%.

(7) Electroless zinc oxide film sheet resistance, transmittance, and film thickness were examined. The results are also shown in Table 3.

[0062]

[Table 2]

[0063]

[Table 3]

Examples 19 and 20 The complexing agent was changed to NaCl
A zinc oxide film was produced in the same manner as in Example 5 except that (Example 19) and MgCl ₂ (Example 20) were used. The physical property evaluation values of the obtained film were almost the same as those in Example 5.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H092 HA03 KA18 MA05 NA01 NA28 NA29 4K022 AA03 AA43 BA15 BA25 BA33 BA36 CA05 CA06 CA07 CA18 CA20 CA21 DA01 DB03 5F051 BA16 CB27 FA02 5G323 BA02 BB01 BC02

Claims (9)

[Claims] 1. A method for forming an electroless zinc oxide film by immersing a substrate having a catalyst layer formed on a surface of a nonconductive substrate in an electroless zinc oxide plating solution containing a borane-based reducing agent. After the substrate is immersed in an electroless zinc oxide plating solution containing a borane-based reducing agent, the substrate is immersed in a Pd treatment solution containing a water-soluble Pd salt and a complexing agent. A method for forming an electroless zinc oxide film, comprising immersing the film in an electrolytic zinc oxide plating solution to form an electroless zinc oxide film. 2. The water-soluble Pd salt concentration in the Pd treatment liquid is 8%.
The method for forming an electroless zinc oxide film according to claim 1, wherein the amount is from × 10 ^{−4 to} 4.5 × 10 ⁻² mol / L. 3. The electroless zinc oxide film according to claim 1, wherein the molar concentration ratio of the water-soluble Pd salt to the complexing agent (water-soluble Pd salt: complexing agent) is 1:10 to 1: 5000. Formation method. 4. The method for forming an electroless zinc oxide film according to claim 1, wherein the pH of the Pd treatment liquid is 2 to 4. 5. The method for forming an electroless zinc oxide film according to claim 1, wherein the complexing agent is a chloride. 6. The substrate on which the catalyst layer is formed is formed by depositing Sn, Ag, and Pd on the surface of a non-conductive substrate by using Sn: Ag: Pd.
= (1 to 10): (1 to 10): a substrate having a high-density Pd nucleus dispersion layer on which a catalyst layer having a weight ratio of (1 to 10) is formed. The method for forming an electroless zinc oxide film according to the above item. 7. The electroless zinc oxide film according to claim 1, wherein the catalyst layer has a catalyst nucleus composed of Sn, Ag, and Pd at a nucleus density of 1500 nuclei / μm ² or more. Method. 8. The method for forming an electroless zinc oxide film according to claim 1, wherein the average roughness of the catalyst layer is 0.5 nm or less. 9. The catalyst core of the catalyst layer has a particle size of 2n.
The method for forming an electroless zinc oxide film according to any one of claims 1 to 8, which is not more than m.