JP4969479B2 - Manufacturing method of substrate with transparent conductive film - Google Patents

Description

The present invention relates to a method for producing a substrate on which a transparent conductive film is laminated. Specifically, a transparent conductive film using gallium-zinc oxide is laminated on the surface of a polymer resin film or a glass plate. It is related with the manufacturing method of the board | substrate which becomes.

  Touch panels, which are now widely used in daily life, are widely used in, for example, cash dispensers (ATMs) such as banks and ticket vending machines. For this purpose, glass plates and films (hereinafter referred to as these) laminated with a so-called transparent conductive film are used. Are collectively referred to as a “substrate with a transparent conductive film.” When the substrate is a film, it is also referred to as a “transparent conductive film”. Specifically, the substrate with a transparent conductive film has properties of transmitting light and transmitting electricity, and is used as an electrode of a touch panel by utilizing such properties.

  In particular, so-called mobile devices such as mobile phones and mobile terminals are increasingly required to be light and thin, and the number of scenes where films are used as substrates is increasing. In a transparent conductive film using a substrate as a film, an indium oxide-tin oxide (ITO) film is widely used as the transparent conductive film.

  The transparent conductive film laminated with this ITO film is generally obtained by laminating ITO on the surface of a polyethylene terephthalate (PET) film by physical vapor deposition (PVD) such as sputtering. Is.

  However, in the conventional transparent conductive film in which ITO is laminated by a sputtering method, the resistance of the transparent conductive layer made of ITO has always been a problem. That is, there are problems such as easy peeling, cracking, and low scratch resistance. When a transparent conductive film is used for a touch panel, the transparent conductive film always keeps being pressed in the same range, so that it is easy to crack or peel off at the pressed part. Since a transparent conductive layer tends to cause scratches, cracks are also generated from the portion, and as a result, the transparent conductive film using such ITO is durable. As a result, the sliding resistance is not so high, and even if it is actually used for a touch panel, problems such as performance degradation occur.

  Furthermore, when such a transparent conductive film is used as a transparent electrode of a touch panel, for example, it may be in contact with a heating element over a long period of time by being located on the surface of an image display device, or the environment may be hot. Exposure to the heat for a long time may degrade the performance of the ITO, i.e., the sheet resistance value may change. In other words, the sheet resistance of the ITO film changes after a long period of time, and as a result, in a touch panel that requires stable performance over a long period of time, its performance is deteriorated and lowered, and this is a problem in terms of heat resistance. It was. Furthermore, recently, ITO itself has been a problem that it is difficult to obtain due to the resource depletion problem.

  Therefore, in order to solve the problems in durability and heat resistance as described above, and as a transparent conductive laminate that can exhibit the same performance as the case of using ITO while using a member that replaces ITO, for example, Patent Document 1 and As described in Patent Document 2, it has been proposed to use a zinc oxide-based material.

JP 2007-113109 A JP 2007-113110 A

  However, in the case of the invention described in Patent Document 1 or Patent Document 2 described above, what is used as a base material is limited to acrylic resin, which is problematic because it cannot be applied to other materials. In other words, although there is a demand for lighter, thinner and shorter devices, there is still a need for transparent electrode plates for touch panels using glass plates as substrates, and polymer resin films are limited to acrylic resins. In view of the fact that there are a wide variety of other polymer resin films, and that it is also widely required to use these various polymer resin films as a base material. In patent literature, it must be said that limiting the base material to acrylic resin is not suitable.

  Further, in these patent documents, a zinc oxide-based transparent conductive film is used in order to exhibit transparent conductivity, and although gallium doping is also described, the zinc oxide-based transparent conductive film in these patent documents is described. It is simply laminated by a conventionally well-known method, but if it is simply laminated, the problems caused in the case of ITO mentioned above, that is, the adhesion is not sufficient, and the heat resistance is sufficient. It is not possible to solve various problems such as.

The present invention has been made in view of such problems, and its purpose is to have controllability of the sheet resistance value as compared with a conventional substrate with a transparent conductive film formed by laminating zinc oxide. At the same time, it is to provide a method for producing a substrate with a transparent conductive film having heat resistance against heat from the outside, that is, having a resistance capable of exhibiting stable performance over a long period of time.

In order to solve the above-mentioned problem, the invention according to claim 1 of the present invention is such that at least a conductive layer and a heat-resistant conductive layer are laminated in this order on a transparent substrate made of glass or a polymer resin film. A method for manufacturing a substrate with a transparent conductive film, wherein the conductive layer and the heat-resistant conductive layer are both laminated by a sputtering method, and a first film formation atmosphere when laminating the conductive layer is: It is based on an argon-hydrogen mixed gas, and the hydrogen concentration is 30% or less by volume, and the second film formation atmosphere when laminating the heat-resistant conductive layer is based on an argon-oxygen mixed gas, In addition, the oxygen concentration is 10% or less by volume ratio .

Invention of Claim 2 of this invention is a manufacturing method of the board | substrate with a transparent conductive film of Claim 1, Comprising: The electroconductive substance which forms the said electroconductive layer is an oxidation formed by containing a zinc oxide. The heat-resistant conductive material that is a zinc-based material and forms the heat-resistant conductive layer is a zinc oxide-based material containing zinc oxide.

Invention of Claim 3 of this invention is a manufacturing method of the board | substrate with a transparent conductive film of Claim 2, Comprising: The said zinc oxide type substance is a gallium oxide zinc oxide (GZO), It is characterized by the above-mentioned. And

  As described above, if the substrate with a transparent conductive film according to the present invention, compared to the conventional substrate with a transparent conductive film, a conductive layer and a heat-resistant conductive layer are laminated on its surface, A substrate with a transparent conductive film having heat resistance as compared with the prior art can be obtained. By using a combination of a conductive layer and a heat-resistant conductive layer, it becomes possible to easily obtain a substrate with a transparent conductive film that obtains heat resistance and at the same time has good controllability of sheet resistance. Then, considering the sheet resistance value, by changing the layer thickness of the conductive layer and the heat-resistant conductive layer, the sheet resistance value can be easily and freely set within a range from several tens Ω / □ to several kΩ / □. Can be set. Therefore, if a polymer resin film is used as the base material of the substrate with a transparent conductive film according to the present invention and it is used as a transparent electrode for a touch panel, it can be used as a transparent conductive film having heat resistance and a low resistance value. The speed of performance degradation or performance degradation of the touch panel can be suppressed.

  Embodiments of the present invention will be described below. The embodiment shown here is merely an example, and is not necessarily limited to this embodiment.

(Embodiment 1)
The substrate with a transparent conductive film according to the present invention will be described as the first embodiment. Before that, the substrate of the substrate is a transparent polymer resin film. In the following description, the transparent conductive film is used. Do this with the film in mind. However, in the following explanation, the substrate is basically not limited to a film, and it is previously noted that the same consideration can be made even for a glass plate, for example.

  The transparent conductive film according to the present embodiment includes at least a transparent substrate made of a polymer resin film, a conductive layer formed by laminating a substance having conductivity, and has conductivity and at the same time heat resistance. It is a board | substrate with a transparent conductive film formed by laminating | stacking the heat-resistant electroconductive layer formed by laminating | stacking the provided substance in this order.

Each will be described in turn below.
First of all, the transparent base film made of a polymer resin as a base material is naturally required to have excellent transparency, for example, polyethylene naphthalate (PEN) film, polyethylene terephthalate (PET) film, polycarbonate film, polystyrene film, polymethyl. A resin film such as a methacrylate film may be used. In this embodiment, a PEN film is used. Moreover, the thickness should just be the thickness according to the thickness of the transparent conductive film required in the apparatus etc. which use the transparent conductive film which concerns on this Embodiment, For example, if it uses as a transparent electrode of a touch panel, The thickness of the base film can be preferably 10 μm or more and 200 μm or less.

  Next, the conductive layer laminated on the surface of the base film made of the polymer resin will be described.

  This conductive layer is laminated on the surface of the transparent substrate film, and becomes the most conductive part in the present embodiment, but in this embodiment as the material, for example, gallium, indium, aluminum, boron, A zinc oxide-based material to which a mixture of zinc and gallium is added is preferable. In this embodiment, gallium-zinc oxide (GZO) is used.

  In this embodiment, the conductive layer is laminated by a physical vapor deposition method (PVD). For example, a direct current (DC) sputtering method, an electron beam (EB) vapor deposition method, a resistance heating vapor deposition method, and a high frequency induction heating method. , A high frequency (RF) sputtering method, or the like may be used. In this embodiment mode, a DC sputtering method is used.

  And the thickness of the electroconductive layer in this Embodiment is 1 nm or more and 10 nm or less, and this thickness should just be determined by the sheet resistance value of the transparent conductive film which concerns on this Embodiment finally set.

  In the first film formation atmosphere provided when performing the DC sputtering method for laminating the conductive layer in this embodiment, an argon-hydrogen mixed gas is used, and the hydrogen concentration at that time is argon- The volume ratio in the hydrogen mixed gas is 30% or less. The reason for this condition will be described later.

  After laminating the conductive layer in this way, a heat resistant conductive layer is then laminated on the surface. This heat resistant conductive layer will be described.

  Although this heat-resistant conductive layer has conductivity in the present embodiment, it becomes a main part that imparts heat resistance in the present embodiment. However, in this embodiment, the material is, for example, gallium or indium. In addition, gallium oxide-zinc oxide (GZO) is used in this embodiment mode.

  In this embodiment, the heat-resistant conductive layer is laminated by physical vapor deposition (PVD) as in the case of the previous conductive layer. For example, direct current (DC) sputtering, electron beam (EB) vapor deposition. Or the like, a resistance heating vapor deposition method, a high frequency induction heating method, a high frequency (RF) sputtering method, or the like may be used. In this embodiment mode, a DC sputtering method is used.

  And although the thickness of the heat resistant conductive layer in this embodiment is 50 nm or more and 500 nm or less, if it is less than 50 nm, the heat resistance cannot be sufficiently exhibited, and if it exceeds 500 nm, the whole transparent conductive film The thickness increases, cracks occur in the conductive layer, and the conductivity is remarkably impaired. Therefore, it can be said that it is preferable to set the thickness within the above range in order to avoid these phenomena.

  In the second film formation atmosphere provided when performing the DC sputtering method for laminating the heat-resistant conductive layer in this embodiment, an argon-oxygen mixed gas is used, and the oxygen concentration at that time is argon. -It shall be 10% or less by volume ratio in oxygen mixed gas. The reason for this condition will be described later.

  Thus, the transparent conductive film according to the present embodiment is formed, but in order to make the interlayer adhesion between the base film and the conductive layer and the heat-resistant conductive layer even more suitable, Prior to laminating the conductive layer, an undercoat layer may be laminated on the surface of the base film.

  When laminating an undercoat layer in the present embodiment, it may be laminated using a generally known material. For example, an undercoat agent of a hydrolyzate of silicon alkoxide is formed by a so-called wet coating method such as a gravure coating method. What is necessary is just to laminate. In this embodiment, a hydrolyzate of silicon alkoxide is laminated to a thickness of 50 nm by a gravure coating method, and this is used as an undercoat layer.

  In addition to the method of providing the undercoat layer, a method of improving the adhesiveness of the conductive layer or the like by performing plasma treatment on the surface of the base film, for example, can be considered, but detailed description thereof is omitted here. .

  In addition, in order to impart these functionalities to the transparent conductive film according to the present embodiment, it is possible to further impart hard coat properties and antireflection properties. A hard coat layer and an antireflection layer are laminated by a conventionally known method and substance on the surface of the material film opposite to the surface on which the undercoat layer, conductive layer, and heat-resistant conductive layer are laminated. However, detailed explanation on these is also omitted here.

  As described above, the transparent conductive film according to the present embodiment has a configuration of base film / undercoat layer / conductive layer / heat-resistant conductive layer. The layers and the heat-resistant conductive layer are made of the same material, that is, GZO, and the laminating method uses the same technique of DC sputtering, but the atmosphere in forming them, that is, the first component is formed. By making the film atmosphere different from the second film formation atmosphere, the characteristics exhibited by the layers of the stacked GZO are different. Therefore, the reason for this will be described below.

  First, an argon-hydrogen mixed gas is used in the first film formation atmosphere, and the hydrogen concentration at that time is 30% or less in terms of the volume ratio in the argon-hydrogen mixed gas. On the other hand, an argon-oxygen mixed gas is used in the second film formation atmosphere, and the oxygen concentration at that time is 10% or less in terms of the volume ratio in the argon-oxygen mixed gas. In any film formation, a DC sputtering method is used.

  That is, the properties of the GZO film to be formed change depending on whether or not oxygen gas is used for the atmosphere when performing DC sputtering. That is, in the GZO film obtained by the first film formation atmosphere and the GZO film obtained by the second film formation atmosphere, the GZO film obtained by the second film formation atmosphere has a higher degree of oxidation.

  Therefore, in other words, the structure of the transparent conductive film according to the present embodiment can be said to have a structure of base film / undercoat layer / low oxidation degree GZO film / high oxidation degree GZO film. .

  Here, the GZO film will be described. This film has the advantage that the transmittance is higher than that of the ITO film, and it is known that the conductivity can be further improved by adding gallium to zinc oxide. It has been. In this embodiment mode, both the conductive layer and the heat-resistant conductive layer are basically made of GZO, so that the adhesion at this portion can be made very suitable. Further, by making the outermost layer a highly oxidized film, even if this part is exposed to a heating element for a long time, the heat hardly affects the inside of the layer structure, and the outermost layer is also a film made of GZO. Therefore, it can be seen that it has a certain conductivity. However, this alone does not provide sufficient conductivity, and in this embodiment, in order to further increase the conductivity, a GZO film having an extremely low degree of oxidation is provided inside the outermost GZO film. .

  In addition, when a GZO film is used, the surface of the film is often very dense and flat, so if it is left as it is, it can be considered that light reflection is likely to occur. It can be said that it is effective to provide the film on the side opposite to the conductive layer lamination side of the base film surface.

  And it becomes easy to change freely the sheet resistance value of the transparent conductive film which concerns on this Embodiment obtained by making a conductive layer and a heat-resistant conductive layer into a GZO film | membrane fundamentally. That is, by changing the film thicknesses of the conductive layer and the body thermal conductive layer, the sheet resistance value obtained can be easily set in the range of several tens of Ω / □ to several kΩ / □.

The value R ₀ measured after leaving the sheet resistance value of the transparent conductive film according to the present embodiment obtained in this way at 90 ° C. for 500 hours is the sheet resistance value before leaving in relation to R. 0.8 ≦ (R / R ₀ ) ≦ 1.5
Although this satisfies the above, it can be said that the provision of the heat-resistant conductive layer indicates that the transparent conductive film is not significantly affected by external heating. That is, in the transparent conductive film according to the present embodiment, the outermost layer has conductivity, but a layer having heat resistance more than that, and the conductive layer located immediately inside thereof has a conductivity similar to that of conventional ITO. Since the heat-resistant conductive layer and the conductive layer are basically made of the same material, the interlayer adhesion can be made suitable, and the heat-resistant conductive layer is externally provided. It can be said that the heat does not affect the inside and that the heat-resistant conductive layer and the conductive layer can maintain sufficient conductivity.

  In the above description, the GZO film has been described. However, if the conductive layer and the heat-resistant conductive layer are made of the same material and are laminated with varying degrees of oxidation, other than the GZO described above. The zinc oxide-based material may be used, and the conductive layer and the heat-resistant conductive layer may be composed of different materials depending on the required properties, etc. The inventor of the present invention has found that it is preferable to use GZO from the viewpoint that the resistance value does not increase.

  Although it is conceivable to use AZO instead of GZO, in this case, although it can be said that it is a suitable choice from the viewpoint of reducing resistance, it is better to use GZO in terms of maintaining heat resistance. As shown and well known, when AZO is used, a film with low sheet resistance cannot be formed unless the substrate temperature is increased to about 200 ° C., whereas in GZO, the substrate temperature remains at room temperature. However, it should also be mentioned that a sheet having a low sheet resistance and usable for practical use can be laminated.

  Although described at the beginning, the above description is made assuming that the base material is a transparent plastic film. However, the same effect can be obtained even if glass is used, and the base material is glass. It should be noted that the same applies to the various laminates.

  Hereinafter, the transparent conductive film-coated substrate according to the present invention will be further described with reference to examples.

  First, a PEN film having a thickness of 125 μm (product name “Teonex” manufactured by Toray DuPont Co., Ltd.) is used as a substrate. As an undercoat layer, an undercoat agent of a hydrolyzate of silicon alkoxide was laminated on the surface so as to have a thickness of 50 nm by a gravure coating method. Using this, laminates according to Examples and Comparative Examples were produced and compared.

Example 1
GZO was laminated to 50 nm as a conductive layer, and GZO was laminated to 150 nm as a heat-resistant conductive layer.
A DC sputtering method was used as a lamination method.
When performing DC sputtering, an argon-hydrogen mixed gas was used as the first film formation atmosphere. The hydrogen concentration was 10% by volume. An argon-oxygen mixed gas was used as the second film formation atmosphere. The oxygen concentration was 2% by volume.

(Example 2)
GZO was laminated to 100 nm as a conductive layer, and GZO was laminated to 100 nm as a heat-resistant conductive layer.
A DC sputtering method was used as a lamination method.
When performing DC sputtering, an argon-hydrogen mixed gas was used as the first film formation atmosphere. The hydrogen concentration was 10% by volume. An argon-oxygen mixed gas was used as the second film formation atmosphere. The oxygen concentration was 5% by volume.

(Example 3)
GZO was laminated to 150 nm as a conductive layer, and GZO was laminated to 50 nm as a heat-resistant conductive layer.
A DC sputtering method was used as a lamination method.
When performing DC sputtering, an argon-hydrogen mixed gas was used as the first film formation atmosphere. The hydrogen concentration was 5% by volume. An argon-oxygen mixed gas was used as the second film formation atmosphere. The oxygen concentration was 1% by volume.

Example 4
GZO was laminated to 150 nm as a conductive layer, and GZO was laminated to 150 nm as a heat-resistant conductive layer.
A DC sputtering method was used as a lamination method.
When performing DC sputtering, an argon-hydrogen mixed gas was used as the first film formation atmosphere. The hydrogen concentration was 5% by volume. An argon-oxygen mixed gas was used as the second film formation atmosphere. The oxygen concentration was 1% by volume.

(Comparative Example 1)
200 nm of GZO was laminated as a conductive layer.
A DC sputtering method was used as a lamination method.
When performing DC sputtering, an argon-hydrogen mixed gas was used as a film forming atmosphere. The hydrogen concentration was 20% by volume.

(Comparative Example 2)
200 nm of GZO was laminated as a conductive layer.
A DC sputtering method was used as a lamination method.
When performing DC sputtering, an argon-hydrogen mixed gas was used as a film forming atmosphere. The oxygen concentration was 5% by volume.

  After measuring the sheet resistance value for each of the transparent conductive films obtained as described above, the sheet resistance value was measured again after being allowed to stand at a temperature of 90 degrees for 500 hours.

  As can be seen from this result, by providing a heat-resistant conductive layer with heat resistance by increasing the degree of oxidation in the outermost layer, it can be seen that heating from outside does not affect the transparent conductive film, It can be seen that the conductivity is not sufficient when a layer having only heat resistance and no conductivity is laminated on the outermost layer.

Claims (3)

At least a method for producing a substrate with a transparent conductive film, wherein a conductive layer and a heat-resistant conductive layer are laminated in this order on a transparent substrate made of glass or a polymer resin film,
Both the conductive layer and the heat-resistant conductive layer are laminated by sputtering,
The first film formation atmosphere when laminating the conductive layer is an argon-hydrogen mixed gas, and the hydrogen concentration is 30% or less by volume ratio,
The second film formation atmosphere when laminating the heat-resistant conductive layer is an argon-oxygen mixed gas, and the oxygen concentration is 10% or less by volume ratio;
The manufacturing method of the board | substrate with a transparent conductive film characterized by these. It is a manufacturing method of the substrate with a transparent conductive film according to claim 1,
The conductive material that forms the conductive layer is a zinc oxide-based material containing zinc oxide,
The heat-resistant conductive material forming the heat-resistant conductive layer is a zinc oxide-based material containing zinc oxide;
The manufacturing method of the board | substrate with a transparent conductive film characterized by these. It is a manufacturing method of the substrate with a transparent conductive film according to claim 2,
The zinc oxide-based material is gallium oxide-zinc oxide (GZO);
The manufacturing method of the board | substrate with a transparent conductive film characterized by these.