JP2000111931A - Substrate with ito transparent conductive film and liquid crystal display element using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a substrate with ITO transparent conductive film having both of greater surface ruggedness and low specific resistance by providing a ruggedness forming layer between a transparent substrate and ITO film so that surface ruggedness of the ITO transparent conductive film becomes specified roughness. SOLUTION: ITO transparent conductive film 21 is applied on a transparent substrate 26 consisting of a glass plate 25 and a color filter 24 of R G B formed on the same. This ITO transparent conductive film 21 is a laminated body of a ruggedness forming layer 23 and an ITO layer 22. This laminated body can be obtained by laminating the ITO film 22 on the substrate 26 with the ruggedness forming layer 23 previously film-formed, however, after film-forming the rugged forming layer 23 on the transparent substrate, the ITO film 22 is preferably rapidly laminated without exposing the ruggedness forming layer to air. And in this case the rugged forming layer 23 is provided between the transparent substrate 26 and the ITO film 22 so that surface ruggedness of the ITO film 22 is >=15 nm based on averaged roughness of 10 observed points.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate on which a transparent conductive film of ITO (tin-containing indium oxide) polycrystal having a small specific resistance and an uneven surface is formed on a transparent substrate. The present invention relates to a substrate on which an ITO transparent conductive film is formed on a filter, and a liquid crystal display device using the same.

[0002]

2. Description of the Related Art Hitherto, several methods have been proposed as a method for lowering the specific resistance of an ITO transparent conductive film. For example, JP-A-9-194232 discloses a film forming method using arc discharge plasma. This method is characterized in that an ITO polycrystalline film can be densely deposited at a low temperature, and the electron carrier density in the film is significantly increased. As a result, the electrical resistance of the transparent conductive film can be significantly reduced. By using this method, an ITO polycrystalline film having a lower specific resistance can be obtained as compared with an ITO polycrystalline film formed by a magnetron sputtering method, which is widely used in the industry at present.

[0003] However, in the case of an ITO polycrystalline film formed by a film forming method using arc discharge plasma, if the specific resistance is to be lowered, the cause thereof is not fully understood, but the property that the surface unevenness of the film is reduced. was there.

[0004]

When the surface roughness of the transparent conductive film becomes small, when the transparent conductive film is used as a transparent electrode of a liquid crystal display element, an organic resin (masking resist) used for patterning by a wet etching method in a manufacturing process thereof. There was a problem that the glue (adhesion) deteriorated and a clean patterning cross-sectional shape could not be obtained. Therefore, if the above-mentioned problems are solved, the ITO transparent conductive film formed by the arc discharge plasma method will have both the low resistance property inherent in the film and the good patterning property of the electrode. However, there has been a technical problem that it becomes practically useful.

[0005] The present invention aims at overcoming the aforementioned disadvantages of the prior art. That is, an object is to obtain a substrate with an ITO transparent conductive film having both larger surface irregularities and low specific resistance.

[0006]

A first aspect of the present invention is a substrate with an ITO transparent conductive film in which an ITO film is formed on a transparent substrate, wherein the surface roughness of the ITO film is represented by 10-point average roughness.
An unevenness forming layer is provided between the transparent substrate and the ITO film so as to have a thickness of 5 nm or more.

When an ITO transparent conductive film is used as a transparent electrode of a liquid crystal display element, an electrode patterning for removing unnecessary portions of the ITO transparent conductive film by acid etching is performed.
An electrode having a predetermined shape is formed. The patterning of the finely shaped electrode is usually performed by a photolithographic method using a masking resist, and in many cases, a positive resist is used. Here, the adhesiveness of the positive type resist to the ITO film is weaker than that of the negative type resist, and in order to improve the adhesiveness, the unevenness of the surface is expressed by a 10-point average roughness of 1 point.
An unevenness forming layer was provided as an underlayer between the ITO film and the transparent substrate so that the thickness was 5 nm or more.

Thus, as will be described later, in etching with an acid, so-called side etching by an etchant is suppressed, and the dimensional accuracy of electrode patterning is improved.

According to a second aspect of the present invention, in the first aspect, the surface roughness of the ITO transparent conductive film is represented by 10 points average roughness of 150 n.
m or less.

The surface has a 10-point average roughness of 150 nm.
This is because, when the surface roughness is further roughened, it becomes difficult to apply a liquid crystal alignment film to a uniform thickness on the surface of the transparent electrode in the liquid crystal cell constituting the liquid crystal display element, and the display is disturbed due to poor alignment of the liquid crystal. In addition, it is difficult to apply a positive resist uniformly, which causes a deviation in dimension of electrode patterning.

[0011] Claim 3 is based on claim 1 or 2,
In a film forming chamber in which an atmosphere in which the pressure of the ITO film is reduced is adjusted, a deposition material of indium oxide containing tin oxide is formed by irradiating the deposition material with arc discharge plasma to evaporate the material.

An ITO film itself obtained by irradiating a vapor deposition material of indium oxide containing tin oxide by irradiating it with arc discharge plasma has a very smooth surface when formed on a smooth substrate. In particular, an ITO film formed by an arc discharge plasma method formed on an organic resin surface where it is difficult to heat the substrate to a high temperature has a smooth surface. The surface of the ITO film formed thereon has an unevenness of 10 μm.
The film is formed to have a point average roughness of 15 nm or more.

A fourth aspect of the present invention is characterized in that, in any one of the first to third aspects, the unevenness forming layer is formed of an acid-soluble transparent metal oxide.

Since the concavo-convex forming layer is made of an acid-soluble metal oxide and is removed by etching with an acid, electrical insulation between the patterned electrodes is ensured.

A fifth aspect of the present invention is characterized in that, in the fourth aspect, the acid-soluble metal oxide is one or a mixture of two or more selected from the group consisting of ITO, indium oxide, and magnesium oxide. .

By forming the concavo-convex formation layer from one of ITO, indium oxide, and magnesium oxide or a mixture thereof, the patterning of the concavo-convex formation layer is performed simultaneously with the ITO film formed on the concavo-convex formation layer. Can be removed by etching with an acid.

A sixth aspect of the present invention is characterized in that, in any one of the first to third aspects, the unevenness forming layer is made of an acid-insoluble and electrically insulating transparent metal oxide.

Since it is acid-insoluble and electrically insulative, electrical insulation between the electrode-patterned ITO films (transparent electrodes) is ensured, and the entire surface of the transparent substrate is covered even after electrode patterning. Therefore, it is possible to prevent impurities existing on the surface of or inside the transparent substrate from diffusing and moving to the surface, and from entering the assembled liquid crystal display element.

According to a seventh aspect of the present invention, in the sixth aspect, the acid-insoluble and electrically insulating transparent metal oxide is made of zirconium oxide or stabilized zirconium.

In these metal oxides, particles grow during the deposition process of the film, and as a result, the surface of the ITO transparent conductive film is given an uneven shape. Further, when these metal oxides are formed in a state where the substrate is heated, the particle growth is more likely to occur, and both the securing of the electrical insulation between the transparent electrodes of the liquid crystal display element and the prevention of contamination are provided.

According to an eighth aspect of the present invention, there is provided a method according to any one of the first to seventh aspects, wherein the unevenness forming layer is evaporated by irradiating with a magnetron sputtering method or an accelerated electron beam in a film forming chamber capable of adjusting a reduced-pressure atmosphere. Characterized in that the film is formed by:

As the magnetron sputtering method,
Known DC or high frequency sputtering can be used, and the metal oxide layer constituting the unevenness forming layer uses the metal oxide or the metal as a target. If necessary, argon containing oxygen can be used as the sputtering gas.

In a vapor deposition method using an accelerated electron beam, when evaporating a vapor deposition material such as a mixture of tin oxide and indium oxide, indium oxide, magnesium oxide, zirconium oxide, and stabilized zirconium, the atmosphere gas in the film formation chamber is reduced to 13%. A film can be formed by a high-frequency ion plating method (hereinafter, referred to as an RFIP method) in which a high frequency of .56 MHz is applied to excite the film to activate and evaporate the vaporized flow molecules.

The ITO film is preferably formed directly on the unevenness forming layer before being exposed to the atmosphere after being formed in the film forming chamber, and is preferably formed quickly. .

A ninth aspect is characterized in that, in the fifth to eighth aspects, the thickness of the unevenness forming layer is 2 nm or more.

When the thickness of the concavo-convex forming layer is 2 nm or more, the particle growth of the ITO film formed thereon increases. The convex part of the concavo-convex formation layer becomes the core of particle growth and
Particle growth of the O film is often performed. On the other hand, since the growth of the ITO film is suppressed in the concave portions of the unevenness forming layer, it is possible to provide the ITO film surface with an uneven shape more than the surface of the unevenness forming layer. If the thickness of the unevenness forming layer is less than 2 nm, the effect of the unevenness formation by the above-described particle growth of the ITO film is undesirably reduced. The thickness of the unevenness forming layer is 5
It is more preferably at least nm.

A tenth aspect is characterized in that, in the ninth aspect, the thickness of the unevenness forming layer is set to 100 nm or less.

When the thickness of the concavo-convex formation layer exceeds 100 nm, it takes a long time to form the film, the efficiency of the film formation is reduced, and the adhesiveness of the resist is not further improved. The effect of the reduction of the amount cannot be obtained remarkably. For the above reasons, the thickness is preferably 100 nm or less.
nm or less is preferable.

The eleventh aspect of the present invention relates to the first to tenth aspects.
The TO transparent conductive film has a specific resistance of 2.0 × 10 ⁻⁴ Ωcm or less.

The specific resistance of the ITO transparent conductive film is 2.0 × 1
By setting the thickness to 0 ^-4 Ωcm or less, preferably 1.6 × 10 ^-4 Ωcm or less, a fine transparent electrode required for high-definition display can be obtained with a relatively small thickness.

A twelfth aspect is the invention according to the first to eleventh aspects.
The uneven formation layer is formed on a color filter for liquid crystal color display provided on a glass plate.

The formation of an ITO film on a color filter containing a pigment or a dye in an organic resin is required to be performed in a temperature range where the color filter is not deteriorated, for example, about 220 ° C. or less. The adhesion between the surface of an organic resin such as a color filter and the ITO film is effectively improved by the surface irregularities of the ITO film.

A thirteenth aspect is a color liquid crystal display device using the substrate with the ITO transparent conductive film according to any one of the first to twelfth aspects as at least one counter substrate.

[0034]

FIG. 1 is a partial sectional view of an embodiment of a substrate 20 with an ITO transparent conductive film according to the present invention.
An ITO transparent conductive film 21 is coated on a transparent substrate 26 composed of a color filter 5 and an RGB color filter 24 formed thereon. The ITO transparent conductive film 21 is a laminate of the unevenness forming layer 23 and the ITO film 22.

This laminate may be formed by laminating an ITO film on a substrate on which a concavo-convex formation layer has been formed in advance, but after forming the concavo-convex formation layer on a transparent substrate, the layer is exposed to the atmosphere. It is preferred that the ITO film be stacked immediately without any problems.

FIG. 2 shows a state in which a masking resist 30 having a stripe shape is formed on the ITO transparent conductive film 21 when a patterning test is performed on the samples obtained in Example 1 and Comparative Example 1. 2A is a plan view, and FIG. 2B is a cross-sectional view.

FIG. 3 schematically shows a cross section of a striped electrode after electrode patterning in Example 1 and Comparative Example 1. In Comparative Example 1, as shown in FIG. 3B, the etching from the side under the masking resist 30 greatly progresses, and the amount of side etching of the ITO film 21 increases.
The width of the electrode is smaller than the concealing dimension. On the other hand, in the first embodiment, as shown in FIG. 3A, an electrode having a small side etch amount can be formed, and an electrode having a size closer to the size of the masking resist is formed. Since the cross-sectional area of the electrodes does not decrease, the electric resistance between the display unit and the power supply unit does not increase, and the voltage drop is suppressed.

FIG. 4 is a schematic sectional view of a film forming apparatus used for continuously forming the ITO transparent conductive film of the present invention.

The first film forming chamber 1 in which the reduced pressure atmosphere can be adjusted by having the vacuum exhaust port 19 connected to the vacuum exhaust means (not shown) and the gas inlet port 17 connected to the gas introducing means (not shown) is the same. A second film forming chamber 2 having a vacuum exhaust port 18 connected to a vacuum exhaust means (not shown) and a gas inlet port 16 connected to a gas introducing means (not shown) and capable of adjusting a reduced-pressure atmosphere. They are connected by a gate valve 12.

At the bottom of the first film forming chamber 1, a sputtering cathode 5 to which a negative voltage can be applied by a DC power supply is provided, and a target 9 made of an ITO sintered body is set on the surface of the cathode 5. . The first layer is formed by I
The sputtering is performed on the surface of the substrate 10 passing over the target by sputtering the TO target in an atmosphere of a mixed gas of oxygen and argon introduced from the gas inlet 17.

The second film forming chamber 2 is provided with an arc discharge plasma generating gun 6 provided on the side wall of the film forming chamber, and the arc discharge plasma generated in the arc discharge plasma generating gun 6 is horizontally magnetized by a magnetic field. The arc discharge plasma 8 is drawn out into the film forming chamber 2 by a magnet 14 for forming a vertical magnetic field provided below the crucible 7 and bent to about 90 degrees by a magnet 15 provided below the crucible 7 so as to be put into the crucible 7. Irradiate the filled deposition material. As a result, the evaporation material is evaporated, and the second
The layer is deposited on the surface of the first layer of ITO of the substrate 10 passing over the crucible.

The arc discharge plasma generating gun 6 is, for example, a known composite cathode type plasma generating gun, a pressure gradient type plasma generating gun, or a combination of both known as described in Vacuum Vol. 25, No. 10 (1982). Can be used.

The transfer from the outside of the substrate to the first film forming chamber 1 is performed via the intake chamber 3 connected to the film forming chamber 1 by a valve 12 which can be opened and closed. Further, the substrate is taken out of the second film forming chamber 2 to the outside through the take-out chamber 4 connected to the second film forming chamber 2 by a valve 12 that can be opened and closed.

The first layer and the second layer are continuously formed on a substrate conveyed by a conveyor 11 such as a roller in a reduced-pressure atmosphere. Also, if necessary, the heater 13
Heats the substrate.

Hereinafter, the present invention will be described with reference to Examples and Comparative Examples. (Embodiment) In any of the embodiments and the comparative examples, the substrate used was a transparent substrate in which RGB color filters for color liquid crystal display were formed on a glass plate. And Examples 1, 4, 5, 8,
10 and the single-layer film of Comparative Example 1 are shown in FIG.
Performed in an in-line type film forming apparatus shown in
In 6, 7, 9, 11, 12 and Comparative Examples 2, 3, and 4, the first layer was formed by another film forming apparatus, and once taken out into the atmosphere, and then stacked by the film forming apparatus of FIG. And The conditions for forming the film are as follows.

Film forming method for unevenness forming layer 1) Sputtering method (SP method)-ITO layer Target: Sintered body of mixed powder of indium oxide 90% by weight and tin oxide 10% by weight Atmosphere during film formation: total pressure 0.04 Pa (Introducing a mixed gas of 98% of argon and 2% of oxygen) ・ MgO layer Target: Metal magnesium Atmosphere during film formation: Total pressure 0.04 Pa (oxygen introduction) ・ ZrO ₂ layer Target: Zirconium oxide Atmosphere during film formation: Total pressure 0 0.04 Pa (mixed introduction of 98% of argon and 2% of oxygen) 2) Electron beam evaporation (EB method) ・ ITO layer evaporation material: powder pellet of 95% by weight of indium oxide and 5% by weight of tin oxide Atmosphere during film formation: 0.004 Pa (oxygen introduction) · in ₂ O ₃ layer deposited materials: powder pellet deposited in an atmosphere of indium oxide: 0.004Pa (introduction of oxygen) · MgO layer deposition material: Magnesium powder sintered body deposition atmosphere: 0.004Pa (introduction of oxygen) · ZrO ₂ layer deposition material: zirconium oxide powder sintered film formation atmosphere: 0.004Pa (introduction of oxygen) 3) high-frequency ion plating Injection method (RFIP method) ・ ITO layer Evaporation material: Powder pellet of 95% by weight of indium oxide and 5% by weight of tin oxide Atmosphere: 0.004 Pa (introduction of oxygen) High frequency power: 200 W (introduction from ring-shaped terminal) ・ ZrO ₂ layer evaporation Material: zirconium oxide powder sintered body Atmosphere: 0.004 Pa (introducing oxygen) High frequency power: 200 W (introduced from ring terminal)

YSZ (stabilized zirconium) layer Evaporation material: A mixture of 92% by weight of zirconium oxide and 8% by weight of yttrium oxide Powder sintered body Atmosphere during film formation: 0.004 Pa (introducing oxygen)

Deposition method of ITO film DC arc discharge plasma method (AP method) Evaporation material: Powder sintered body of 95% by weight of indium oxide and 5% by weight of tin oxide Atmosphere during film formation: total pressure of 0.027 Pa (argon and oxygen) And an oxygen partial pressure of 0.0080 Pa) arc discharge plasma gun: composite cathode type, discharge current: 150 A discharge voltage: 98 V

Description of Table 1 SP-DC: DC magnetron sputtering SP-RF: High frequency magnetron sputtering EB: Electron beam evaporation RFIP: High frequency plasma ion plating AP: Arc discharge plasma

Explanation of Table 2 Sheet resistance (Ω / □): Measured by a four-terminal resistance meter. -Specific resistance (× 10 ^-4 Ωcm): Calculated from sheet resistance and film thickness. -10-point average roughness (nm): Measured by atomic force microscope observation, expressed as a value specified in JIS B0601. Patterning test: A striped electrode pattern was formed by a photolithographic method using a positive photoresist, and 47% hydrobromic acid was etched with an etching solution. The amount of bite from the edge of the resist in the electrode cross section shown in FIG. 3 was measured as the side etch amount.

Example 1 As a preliminary study, ITO was deposited to a thickness of 100 nm on a glass plate by a DC magnetron sputtering method, and the surface roughness of the ITO surface was measured by an atomic force microscope.
The zero point average roughness Rz is 6.0 nm and the sheet resistance is 2
It was 1.2 Ω / □. A 100-nm ITO film was formed by the arc discharge plasma method, and the surface roughness was measured in the same manner as described above. The 10-point average roughness Rz was 1.5 nm.
And the sheet resistance was 15.0 Ω / □. Thereby, the IT formed by the DC magnetron sputtering method
O has a higher resistance than the film obtained by the arc discharge plasma method, but it has been confirmed that the particle growth during the film formation process is large and the surface irregularities of the film are rough. On the other hand, ITO formed by the arc discharge plasma method has a smooth surface,
It was confirmed that the film had a lower resistance.

Next, a 10 nm thick ITO film was formed as a concavo-convex formation layer on the color filter by a DC magnetron sputtering method using a film forming apparatus shown in FIG. 4, and the ITO film was formed thereon by an arc discharge plasma method without being exposed to the atmosphere. A conductive film was formed. The latter ITO conductive film is once evacuated to a pressure of 0.0027 Pa or less by a vacuum evacuation pump, and then argon gas is introduced thereinto.
A current of 50 A was supplied to generate arc discharge plasma to obtain a substrate with an ITO transparent conductive film. During the film formation, a mixed gas of an argon gas and an oxygen gas was introduced from a gas inlet for adjusting the atmosphere to keep the gas pressure and composition of the atmosphere constant and to adjust the total film thickness to 300 nm.

Table 1 shows the laminated structure of the obtained ITO transparent conductive film, and Table 2 shows the film characteristics. As shown in Table 2, this I
The TO transparent conductive film has a specific resistance of 1.3 × 10 ⁻⁴ Ωcm, R
It was an ITO polycrystalline film having a low specific resistance of z = 18.0 nm and large surface irregularities. Further, when the substrate with the ITO transparent conductive film was subjected to electrode patterning and the cross-sectional shape thereof was observed, the amount of side etching was 1.5 μm, and no gap was observed at the interface between the resist and the ITO.

[0054]

[Table 1] ============================== Concavo-convex Forming Layer ITO Film Example Layer Material Film Forming Method Thickness Film Forming Method Thickness (Nm) (nm) Example 1 ITO SP-DC 10 AP 290 Example 2 ITO EB 30 AP 270 Example 3 ITO RFIP 30 AP 270 Example 4 ITO SP-DC 5 AP 295 Example 5 ITO SP-DC 2 AP 298 Example 6 In ₂ O ₃ EB 30 AP 300 Example 7 In ₂ O ₃ EB 50 AP 300 Example 8 MgO SP-RF 50 AP 300 Example 9 MgO EB 60 AP 300 Example 10 ZrO ₂ SP-RF 80 AP 300 Example 11 ZrO ₂ EB 80 AP 300 Example 12 ITO EB 100 AP 200 Example 13 YSZ EB 50 AP 300 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Comparative Example 1 − − − AP 300 Comparative Example 2 In ₂ O ₃ EB 1 AP 300 Comparative Example 3 MgO EB 1 AP 300 Comparative Example 4 ZrO ₂ SP-RF 1 AP 300 ======================= ========

Example 2 As a preliminary study, ITO was reduced to 1 by electron beam evaporation.
When the surface roughness of the ITO surface was measured by an atomic force microscope, the sheet resistance was 23.8 Ω /
□ The 10-point average roughness Rz was 8.3 nm. As a result, it was confirmed that the ITO film formed by the electron beam evaporation method had higher resistance but larger particle growth and rougher surface irregularities of the film than the ITO film formed by the arc discharge plasma method.

A 30 nm film is formed as a concavo-convex forming layer on the substrate under the same film forming conditions as the above-mentioned ITO.
A second ITO film was formed by an arc discharge plasma method so as to have a thickness of 0 nm. Table 2 shows the results. This ITO transparent conductive film has a specific resistance of 1.4 × 10 ⁻⁴ Ωcm and Rz = 2.
IT with low specific resistance of 3.0 nm and large surface irregularities
It was an O polycrystalline film. When a patterning test was performed, the amount of side etching was 1.2 μm, and no gap was observed as in Example 1.

Example 3 As a preliminary study, ITO was deposited to a thickness of 100 nm by ion plating using RF plasma, and the surface roughness of this film was measured by an atomic force microscope.
The zero point average roughness Ra was 5.2 nm, and the sheet resistance was 18.
It was 1 Ω / □. As a result, ITO formed by the ion plating method using RF plasma has a higher resistance than ITO formed by the arc discharge plasma method, but has a larger particle growth during the growth process.
It was confirmed that the surface irregularities of the film were rough.

This ITO was formed as a concavo-convex formation layer to a thickness of 30 nm, and then a second layer of ITO was laminated by an arc discharge plasma method so that the total thickness of the ITO film became 300 nm. Table 2 shows the properties of the obtained ITO transparent conductive film. This ITO transparent conductive film has a specific resistance of 1.4 × 10 ⁻⁴ Ωcm.
And Rz = 15.6 nm. A patterning test was performed on this substrate with an ITO transparent conductive film. As a result, the amount of side etching was 1.9 μm, and no gap was observed as in Example 1.

[0059]

[Table 2] ================================= Example Sheet Resistance Specific Resistance Surface Roughness Rz Patterning Test ( Ω / □) (× 10 ⁻⁴ Ωcm) (nm) (side etch amount μm) −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− −−−− Example 1 4.30 1.3 18.0 1.5 Example 2 4.67 1.4 23.0 1.2 Example 3 4.55 1.4 15.6 1.9 Example 4 4.19 1.3 17.1 ≦ 2.0 Example 5 4.20 1.3 15.3 2.0 Example 6 4.80 1.4 25.1 ≦ 2.0 Example 7 5.22 1.6 25.2 ≦ 2.0 Example 8 5.10 1.5 16.9 ≦ 2.0 Example 9 5.20 1.6 21.1 ≦ 2.0 Example 10 4.91 1.5 17.3 ≦ 2.0 Example 11 5.33 1.6 22.4 ≦ 2.0 Example 12 6.51 2.0 25.3 1.6 Example 13 5.20 1.6 20.3 ≦ 2.0 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Comparative Example 1 4.70 1.4 5.8 8 to 12 Comparative Example 2 4.71 1.4 6.1 7 to 10 Comparative Example 3 4.90 2.0 9.5 5 to 8 Comparative Example 4.81 1.6 10.6 5-7 ==================================

Examples 4 to 11 A layer of concavo-convex was formed by changing the layer material, the film formation method and the thickness, and ITO was formed thereon by the arc discharge plasma method so that the total thickness of the ITO was 300 nm. The films were stacked.
Table 2 shows the properties of the obtained ITO transparent conductive film. Each of the ITO transparent conductive films has a specific resistance of 1.6 × 10 ⁻⁴ Ωcm.
And a low specific resistance, and in the patterning test, the side etch was 2.0 μm or less, and almost no gap was observed at the interface between the resist and the ITO.

Example 12 Example 2 differs from Example 2 in that the total thickness of the ITO transparent conductive film was 300 nm.
An ITO transparent conductive film having a laminated structure shown in Table 1 was formed in exactly the same manner except that the thickness of the unevenness forming layer was changed to 100 nm. In this ITO transparent conductive film, since the thickness of the concavo-convex forming layer was larger than that in Example 2, the surface roughness was large. However, the specific resistance became slightly larger (poor).

Example 13 An IT was prepared in the same manner as in Example 11 except that a stabilized zirconium layer having a thickness of 50 nm was used as the unevenness forming layer.
An O transparent conductive film was formed. The results, as shown in Table 2,
The film had a low specific resistance, and the surface irregularities had characteristics that enabled electrode patterning with high dimensional accuracy.

COMPARATIVE EXAMPLE 1 (Single-layer film by AP method)
An ITO single layer film having a thickness of nm was formed. Table 2 shows the properties of the obtained transparent conductive film. This ITO transparent conductive film had a small specific resistance of 1.4 × 10 ⁻⁴ Ωcm, but had a small surface roughness Rz = 5.8. This IT
When the O transparent conductive film was subjected to a patterning test, the amount of side etching was as large as 8 μm. When observing the cross-sectional shape of the electrode, a gap was clearly observed at the interface between the resist and the ITO.

Comparative Examples 2 to 4 By changing the material, thickness and film forming method of the unevenness forming layer, samples were obtained in which an ITO transparent conductive film having a laminated structure shown in Table 1 was formed. Table 2 shows the properties of the obtained ITO transparent conductive film. Comparative Examples 2, 3 and 4 have small values of Rz Comparative Examples 2 and 4 had low specific resistances. However, the surface resistance of the ITO transparent conductive film was small due to the small thickness of the concavo-convex forming layer and the adhesion to the photoresist was weak.

As described above, according to the embodiment of the present invention,
The TO transparent conductive film has a surface roughness of 1 point average roughness of 1 point.
Since the thickness is 5 nm or more, the amount of side etching is small, that is, it is possible to perform electrode patterning substantially as the dimensions of the masking resist. Further, by adjusting the thickness of the unevenness forming layer to a predetermined range, 1.6 × 10 ⁻⁴ Ωcm
A film having a smaller low specific resistance can be obtained.

[0066]

According to the present invention, an ITO transparent conductive film formed on a transparent substrate is formed into a two-layer structure, and the side far from the substrate is formed as a low-resistivity ITO film so that the surface thereof is provided with irregularities. Since the unevenness forming layer is provided between the transparent substrate and the ITO film, the ITO transparent conductive film can be a film having both surface roughness and low specific resistance. Thereby, the ITO of the present invention
The transparent conductive film has high adhesion to a masking resist used for electrode patterning by acid etching, and can perform electrode patterning with high dimensional accuracy.

When an ITO film is formed by irradiating an indium oxide-containing material containing tin oxide with an arc discharge plasma and evaporating the same in a film forming chamber in which a reduced-pressure atmosphere can be adjusted, 2 × 10 ⁻ An ITO film having a low specific resistance of ⁴ Ωcm or less can be obtained.

Further, by forming the concavo-convex forming layer with an acid-soluble transparent metal oxide, it is possible to perform etching with an acid simultaneously with the ITO film, and to improve the efficiency of electrode patterning in one step.

Further, when the unevenness forming layer is formed of an acid-insoluble and electrically insulating metal oxide film, the electrical insulation of the electrode-patterned electrode is ensured, and the ITO film is formed after the electrode patterning of the ITO film. The unevenness forming layer of the metal oxide also exists in the removed portion. This allows
Diffusion and elution of impurities from the transparent substrate are suppressed, and contamination in the liquid crystal element is prevented.

The unevenness-forming layer is formed by a magnetron sputtering method or a vapor deposition method of evaporating by irradiating an accelerated electron beam in a film formation chamber in which a reduced-pressure atmosphere can be adjusted, whereby the surface unevenness of the ITO transparent conductive film is reduced. It can be formed effectively.

By setting the thickness of the unevenness forming layer within a predetermined range, it is possible to effectively impart unevenness to the surface of the ITO transparent conductive film from the viewpoint of film formation cost.

The ITO transparent conductive film formed on a color filter for liquid crystal color display can perform electrode patterning with high dimensional accuracy even when formed at a low temperature.

The ITO transparent conductive film of the present invention suppresses the occurrence of side etching due to wet etching in the electrode patterning step in the liquid crystal cell manufacturing step.
There is no thinning of the electrode pattern, the voltage drop of the electrode from the power supply unit to the display unit is reduced, and as a result, there is no display unevenness.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of one embodiment of a substrate with an ITO transparent conductive film of the present invention.

FIG. 2 is a view for explaining a state of a masking resist formed on an ITO transparent conductive film of the present invention.

FIG. 3 is a schematic cross-sectional view for explaining cross sections of the samples of Example 1 and Comparative Example 1 after etching with an acid.

FIG. 4 is a schematic cross-sectional view of one embodiment of a film forming apparatus used to carry out the present invention.

[Explanation of symbols]

1: first film forming chamber, 2: second film forming chamber, 3: intake chamber, 4: take-out chamber, 5: sputtering cathode,
6: arc discharge plasma generating gun, 7: crucible, 8: arc discharge plasma, 9: ITO target, 10: substrate, 11: transport conveyor, 12: gate valve, 13:
Heater, 14: Magnetic coil for generating a horizontal magnetic field, 15:
Magnets 16 and 17: gas inlets, 18 and 19: vacuum exhaust ports, 20: substrate with ITO transparent conductive film, 21: ITO transparent conductive film, 22: ITO film, 23: unevenness forming layer, 24:
Color filter, 25: glass plate, 26: transparent substrate, 3
0: Masking resist

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H090 JA05 JB02 JC03 2H091 FB07 FC02 FC26 GA03 LA11 2H092 GA17 GA34 HA04 KA06 KB13 MA05 MA09 NA15 NA28 NA29 PA01 5C094 AA05 AA32 BA43 DA13 EA05 EB02 GB01 JA05 JA08

Claims (13)

[Claims] 1. An IT in which an ITO film is formed on a transparent substrate
In the substrate with the O transparent conductive film, an unevenness forming layer is provided between the transparent substrate and the ITO film such that the surface unevenness of the ITO transparent conductive film is 15 nm or more expressed by a 10-point average roughness. Substrate with an ITO transparent conductive film. 2. The method according to claim 1, wherein the ITO transparent conductive film has a surface irregularity of 1
The substrate with an ITO transparent conductive film according to claim 1, wherein the substrate has a zero point average roughness of 150 nm or less. 3. The ITO film is formed by irradiating a vapor deposition material of indium oxide containing tin oxide by irradiating the vapor deposition material with arc discharge plasma in a deposition chamber in which a reduced-pressure atmosphere is adjusted. 3. The substrate with an ITO transparent conductive film according to claim 1, wherein 4. The substrate with an ITO transparent conductive film according to claim 1, wherein the unevenness forming layer is made of an acid-soluble transparent metal oxide. 5. The method according to claim 1, wherein the acid-soluble transparent metal oxide is IT
The substrate with an ITO transparent conductive film according to claim 4, wherein the substrate is one or a mixture of two or more selected from the group consisting of O, indium oxide, and magnesium oxide. 6. The substrate with an ITO transparent conductive film according to claim 1, wherein the unevenness forming layer is made of an acid-insoluble and electrically insulating transparent metal oxide. 7. The ITO according to claim 6, wherein the acid-insoluble and electrically insulating transparent metal oxide is made of zirconium oxide or stabilized zirconium.
Substrate with transparent conductive film. 8. The method according to claim 1, wherein the unevenness forming layer is formed by a magnetron sputtering method or a vapor deposition method of evaporating by irradiating an accelerated electron beam in a film forming chamber in which a reduced-pressure atmosphere can be adjusted. 8. The substrate with an ITO transparent conductive film according to any one of items 1 to 7. 9. The method according to claim 5, wherein the thickness of the unevenness forming layer is 2 nm or more.
Substrate with TO transparent conductive film. 10. The substrate with an ITO transparent conductive film according to claim 9, wherein the thickness of the unevenness forming layer is 100 nm or less. 11. The specific resistance of the ITO transparent conductive film is as follows:
The substrate with an ITO transparent conductive film according to claim 1, wherein the substrate has a resistivity of 1.6 × 10 ⁻⁴ Ωcm or less. 12. The method according to claim 1, wherein the unevenness forming layer is formed on a color filter for liquid crystal color display provided on a glass plate. Substrate with ITO transparent conductive film. 13. The I according to claim 1, wherein
A color liquid crystal display device using a substrate with a TO transparent conductive film as at least one counter substrate.