JP4269587B2 - Conductive laminate and method for producing the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a conductive laminate. In particular, the present invention relates to a conductive laminate having good etching characteristics and excellent alkali resistance in a manufacturing process when used for a display medium such as a liquid crystal display and a touch panel.
[0002]
[Prior art]
Currently, various types of displays such as liquid crystal displays, plasma displays, and organic EL displays have been put into practical use. In any type of display, the substrate is made of glass. However, when considering displays for portable information terminals such as mobile phones, notebook computers, and PDAs, it is not suitable to use glass as a base material because impact resistance, light weight, etc. are required as display characteristics. Conceivable. Therefore, a display using plastic as a base material that can satisfy these requirements is desired.
[0003]
The film to the base material for the above applications, Ru needs to be deposited on the substrate at least a transparent conductive film as an electrode is Ah. As the transparent conductive thin film, a film obtained by depositing a mixed oxide of indium and tin (hereinafter referred to as ITO), tin oxide, zinc oxide, or the like using a vapor deposition method, a sputtering method, or the like is used. Among them, ITO is used in most applications.
[0004]
In the case of a liquid crystal display application, it is necessary to pattern the transparent conductive thin film. As a method for patterning the transparent conductive layer, a wet etching method is mainly used. The steps are in the order of a resist coating step, a drying step, an exposure step, a development step, an etching step, and a resist stripping step. Since an alkaline solution is used in the resist stripping process, the transparent conductive film is used. Resistance to alkaline solution is required.
[0005]
Further, in an etching process for etching the transparent conductive thin film with an acidic solution such as hydrochloric acid. At this time, the higher the etching speed, the better from the viewpoint of productivity. Therefore, it is necessary to deposit a transparent conductive thin film that is easily dissolved in an acidic solution.
[0006]
However, when an ITO film formed on a plastic film is subjected to alkali treatment, phenomena such as changes in surface resistance and surface turbidity occur. This is because the ITO thin film is peeled off by alkali treatment because the adhesion between the plastic film and the ITO thin film is poor.
[0007]
[Problems to be solved by the invention]
The present invention has been made based on the above circumstances. The object of the present invention is to provide excellent adhesion between the base material and the conductive layer, high alkali resistance, excellent etching characteristics, and desired conductivity. The object is to obtain a conductive laminate having characteristics. Furthermore, there exists in obtaining the transparent conductive laminated body which is excellent in flexibility and has high light transmittance.
[0008]
[Means for Solving the Problems]
According to the first aspect of the present invention, in the conductive laminate in which a conductive layer is provided on at least one surface of the substrate, the conductive layer is formed by laminating a crystalline layer and an amorphous layer in order from the substrate side. And the conductive layer is a crystalline laminate and an amorphous layer, both of which are indium oxide, and the thickness of the crystalline layer is 10 nm or less. is there.
[0009]
The invention according to claim 2 is the conductive laminate according to claim 1, wherein the substrate has flexibility and is transparent.
[0011]
Invention described 請 Motomeko 3, heated on one side of the substrate content of tin was deposited an indium oxide is 0-5%, the base material to 0.99 ° C. after film forming or deposition Forming a crystalline layer, and forming an oxide of indium and tin having a tin content of 10% or more on the upper surface of the crystalline layer at a substrate temperature of 20 ° C. or less. And a step of forming a non-crystalline layer in order.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
[0013]
Although the base material used by this invention is not specifically limited, It is preferable to use a transparent plastic film. It is because it has high transparency and flexibility. Examples of such plastic films include polyolefin (polyethylene, polypropylene, etc.), polyester (polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc.), polyamide, polyimide, polyacrylate, polycarbonate, polyacrylate, polyethersulfone, etc. It is a non-stretched or stretched film of a copolymer and is appropriately selected depending on the application.
[0014]
Especially for flat panel displays, in addition to transparency, there is no heat resistance to the process of forming a transparent electrode film or alignment film, and optical anisotropy ( Polyacrylate, polycarbonate, polyether sulfone, amorphous polyolefin, and the like are preferably used because of their low retardation.
The surface of these plastic films may be subjected to pretreatment such as corona treatment or antistatic treatment.
[0015]
The present invention is characterized in that a conductive layer formed by sequentially laminating a crystalline layer and an amorphous layer is provided on a substrate.
Although it does not specifically limit as a conductive layer, Indium oxide etc. are mentioned. The indium oxide may be a composite oxide with another metal. From the viewpoint of transparency and conductivity, a composite oxide of indium and tin (ITO) is preferable.
The crystalline layer and the non-crystalline layer may be different substances, but are preferably the same substance. In particular, the crystalline layer and the non-crystalline layer are preferably ITO as described above.
[0016]
As described above, the base material side of the conductive layer is a crystalline layer. By setting it as such a structure, the adhesiveness of a base material and a conductive layer improves. And when passing through an alkali treatment process etc., the tolerance with respect to an alkaline solution improves.
Such a crystalline layer may be formed in any way. For example, there is a method in which a layer having low crystallinity is formed by a known method and then crystallized. As such a film forming method, for example, a sputtering method, an ion plating method, a CVD method and the like are suitable because a stable thin film can be obtained. Of these, the DC magnetron sputtering method is desirable.
[0017]
There is no particular limitation on the method of crystallization when a layer having low crystallinity is formed in advance and then crystallized as long as it can be crystallized. For example, there are heating, active energy ray processing and the like.
In the case of crystallization by heating, the base material on which the low crystallinity layer is formed may be heated to 150 ° C. or higher.
[0018]
As a method for providing a crystalline layer directly on a substrate, there is a high temperature film formation method. Specifically, the film is formed by the above-described known film formation method while keeping the substrate at a high temperature, and a crystalline layer with high crystallinity is obtained directly. The temperature of the substrate at this time is preferably 150 ° C. or higher.
[0019]
In addition, when using indium oxide or ITO as the crystalline layer, it is generally said that the lower the tin content, the higher the crystallinity, so use a tin content of 0 to 5 wt%. Is preferred. If the tin content exceeds 5%, it is difficult to crystallize during film formation, and the crystallinity also deteriorates. In this case, even if it is attempted to crystallize by heating after film formation, it takes time to crystallize and the productivity is poor.
[0020]
In addition, since the crystalline layer has an extremely low etching speed as compared with the non-crystalline layer, the thick deposition of the crystalline layer leads to deterioration of productivity. Therefore, it is preferable to deposit as thin a crystalline layer as possible. Specifically, it is desirable that the crystalline layer has a thickness of 10 nm or less.
[0021]
The above-mentioned crystalline layer can only obtain a surface resistance value of about 300Ω / □ even if the surface resistance value is low. Therefore, if the application requires a lower resistance value, such as a liquid crystal display substrate, a non-crystalline layer having a high etching speed is formed on the crystalline layer to obtain a desired resistance value. Need to be low.
[0022]
As a method for forming such an amorphous layer, a known method can be used. For example, a sputtering method, an ion plating method, a CVD method and the like are suitable because a stable thin film can be obtained. Of these, the DC magnetron sputtering method is desirable.
[0023]
Moreover, since the base material temperature in film-forming will crystallize when too high, it is preferable that it is 20 degrees C or less. When ITO is used as the non-crystalline layer, it is preferable to use a tin content of 10% or more because crystallization hardly proceeds. Moreover, when using the electroconductive laminated body of this invention for a film liquid crystal etc., it is necessary to use a thing with as low a resistivity as possible. When the tin content of ITO increases, the resistivity increases with 10% as a boundary. Preferably, the tin content is 10% to 20%.
[0024]
The film thickness may be a thickness that provides a desired surface resistance value, but is preferably about 150 nm in consideration of light transmittance and the like. Further, the surface resistance value is desirably 40 Ω / □ or less.
[0025]
Moreover, in this invention, you may provide overcoat layers, such as an anchor layer for raising adhesiveness, a protective layer, an antifouling layer. Furthermore, functional layers such as a gas barrier layer and an optical layer may be laminated.
[0026]
【Example】
<Example 1>
A polycarbonate film having a thickness of 100 μm (manufactured by Teijin: Panlite) was used as the substrate. The crystalline layer was formed to a thickness of 10 nm by a DC magnetron sputtering method using an ITO target having a tin content of 5 wt%. The substrate temperature during film formation was 150 ° C. When this film was measured using an X-ray diffractometer, 222 peak of indium oxide was observed at 2θ around 30 °, and it was confirmed that the film had crystallinity. The amorphous layer was formed to a thickness of 140 nm by a DC magnetron sputtering method using an ITO target having a tin content of 10 wt%. The substrate temperature during film formation was 10 ° C.
[0027]
It was 37.5 ohms / square when the surface resistance value of the obtained electroconductive laminated body was measured using the surface resistance measuring apparatus (Mitsubishi Chemical make: Loresta HP). Further, when the spectral characteristics were measured, the light transmittance at 550 nm was 87.0%. When this conductive laminate was immersed in a 5 wt% NaOH solution (40 ° C.) for 5 minutes and the surface resistance was measured in the same manner, it was 37.7Ω / □, and the light transmittance at 550 nm was 87%. Met. Also, no change such as cloudiness was observed in appearance.
Further, when the conductive layer (ITO) was etched using 1N hydrochloric acid (40 ° C.), it was confirmed that the conductive layer (ITO) was etched away in 58 seconds.
[0028]
<Example 2>
The same polycarbonate film as in Example 1 was used as the substrate. The crystalline layer was formed to a thickness of 10 nm by a DC magnetron sputtering method using an ITO target having a tin content of 5 wt%. The temperature of the substrate during film formation was 10 ° C. This was crystallized by heating at 150 ° C. using a halogen lamp. Thereafter, an amorphous layer was formed in the same manner as in Example 1.
The surface resistance value of the obtained conductive laminate was 40.5Ω / □. The surface resistance value after the alkali treatment was 40.5Ω / □. The light transmittance at 550 nm was 87.0% before and after the treatment.
Further, when etching was performed using the above-mentioned hydrochloric acid, it was confirmed that the conductive layer (ITO) was etched away in 55 seconds.
[0029]
<Comparative Example 1>
The same polycarbonate film as in Example 1 was used as the substrate. A 10 nm film was formed by DC magnetron sputtering using an ITO target having a tin content of 5 wt% as the first layer on the substrate. The substrate temperature during film formation was 10 ° C. When this film was measured using an X-ray diffractometer, 222 peak of indium oxide was observed at 2θ around 30 °, and it was confirmed that the film had crystallinity. The second layer was formed to a thickness of 140 nm by a DC magnetron sputtering method using an ITO target having a tin content of 10 wt%. The substrate temperature during film formation was 10 ° C.
Note that the two conductive layers were amorphous. The surface resistance value of the obtained conductive laminate was 48.2Ω / □. The light transmittance at 550 nm was 86.4%. The resistance value after the alkali treatment was 60.5Ω / □, and the light transmittance was 84.2%.
[0030]
<Comparative example 2>
The same polycarbonate film as in Example 1 was used as the substrate. A 10 nm film was formed by DC magnetron sputtering using an ITO target having a tin content of 20 wt% as the first layer on the substrate. The substrate temperature during film formation was 100 ° C. The second layer was formed to a thickness of 140 nm by a DC magnetron sputtering method using an ITO target having a tin content of 10 wt%. The substrate temperature during film formation was 10 ° C.
Note that the two conductive layers were amorphous. The obtained conductive laminate had a surface resistance value of 45.9 Ω / □ and a light transmittance at 550 nm of 86.2%. When this film was alkali-treated, the surface resistance value was 53.2 Ω / □, and the light transmittance was 85.6%.
[0031]
<Comparative Example 3>
A polycarbonate film was used as the substrate in the same manner as in Example 1. On this substrate, an ITO thin film having a thickness of 150 nm was formed by DC magnetron sputtering using an ITO target having a tin content of 5 wt%. The temperature of the base material during film formation was 150 ° C. The obtained conductive laminate had a surface resistance value of 40.2Ω / □ and a light transmittance of 550 nm of 87.2%. When this film was alkali-treated, the surface resistance value was 40.3Ω / □, and the light transmittance was 87.1%. When this was etched with 1N hydrochloric acid (40 ° C.), the ITO thin film was not lost even after immersion for 10 minutes.
[0032]
【The invention's effect】
The conductive laminate of the present invention has excellent adhesion between the base material and the conductive layer, the surface resistance value does not change even when immersed in an alkaline solution, and there is no change in appearance such as cloudiness, and the etching characteristics are excellent. Therefore, it can be suitably used for display applications such as film liquid crystal.
[0033]
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing an embodiment of the present invention.
[Explanation of symbols]
1 Base material 2 Crystalline layer 3 Amorphous layer

Claims (3)

In a conductive laminate having a conductive layer on at least one surface of a substrate,
The conductive layer is formed by laminating a crystalline layer and an amorphous layer in order from the substrate side, and
Both the crystalline layer and the non-crystalline layer that are the conductive layers are indium oxide, and
A conductive laminate having a thickness of the crystalline layer of 10 nm or less.   The conductive laminate according to claim 1, wherein the base material has flexibility and is transparent. A step of forming a crystalline layer by forming an indium oxide having a tin content of 0 to 5% on one surface of a base material and heating the base material to 150 ° C. during or after the film formation. When,
A step of forming a non-crystalline layer on the top surface of the crystalline layer by forming indium and tin oxide having a tin content of 10% or more at a base material temperature of 20 ° C. or less; A method for producing a conductive laminate.

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