JPH02276630A - Transparent conductive laminate and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain the conductive laminate excellent in durability and reliability by a method in which a transparent conductive layer is a film wherein crystalline part and amorphous part are mixed, and its crystallinity is specified. CONSTITUTION:In a film, crystalline part and amorphous part are mixed and its crystallinity is 1-80%. First, the layer containing mainly indium oxide and having the absorbancy index of 1.0X10<-5>-3.9X10<-5>[Angstrom <-1>] for the wave length of 550nm and the specific resistance of 4.0X10<-4>-1.4X10<-3>OMEGA.cm is formed on an organic polymer formed object, and next, this layer is heat-treated, whereby said film may be formed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a conductive laminate and a method for manufacturing the same, and more specifically, to a method for forming a transparent conductive layer mainly made of indium oxide on an organic polymer molded product. The present invention relates to a conductive laminate and a method for manufacturing the same.

[Prior Art] With the advent of a highly information-oriented society, there has been remarkable progress in parts and equipment that utilize the characteristics of both optics and electronics. Furthermore, with the rapid spread of microcomputers, innovations in computer peripherals have been remarkable. Transparent electrodes are used in transparent touch panels as computer input devices, as well as liquid crystal displays and electroluminescent displays as output devices, but the durability and reliability of transparent electrodes are required for these purposes. Ru.

As the transparent conductive layer, metal thin film (Au, Pd, etc.) type, metal oxide thin film type (ITO1CTO1Snot
, Ti0z, etc.), multilayer thin film type (T i Ox /
(Ag/TiOx, etc.), but the metal oxide thin film type is superior in basic properties such as transparency, conductivity, and mechanical properties.

Among the metal oxide thin film types, ITO (Indiu
mTin Oxide) film has particularly excellent transparency and conductivity, and also has characteristics such as easy electrode patterning (excellent etching properties), and has attracted attention in recent years.
The valley has fallen.

On the other hand, recent advances in thin film forming technology have been remarkable, and it has become possible to form transparent conductive layers on organic polymer moldings that do not have much heat resistance. Among them, the sputtering method is one of the most used techniques because it has the characteristics of being able to form a film over a long period of time, having no compositional deviation even after long-term film formation, and being easy to widen the film width. It is also known to form the above-mentioned ITO film by a sputtering method.

Therefore, the present inventors also formed an ITO film on an organic polymer molded article using a sputtering method and evaluated its practicality.

However, when a conductive laminate formed by forming a TTO film using a sputtering method is used in an electroluminescent display, disconnections often occur in the transparent conductive layer during the process of bonding the conductive laminate and the light emitting layer. It became clear that there was a big problem.

Therefore, the present inventors first formed a layer containing mainly indium oxide and having a light absorption rate of 2 to 30% at a wavelength of 550 nm and a specific resistance of 1.5 x 10-3 Ωcm or more on an organic polymer molded product. proposed a method in which the core layer is converted into a transparent conductive layer mainly consisting of crystalline indium oxide by heat treatment in an oxygen atmosphere (Japanese Patent Laid-Open No. 61-79).
Publication No. 647). This method also had the problem of wire breakage.

[Problems to be Solved by the Invention] An object of the present invention is to provide a conductive laminate having excellent durability and reliability, and a method for manufacturing the same.

(Means for Solving the Problems) The present invention provides a conductive laminate in which a transparent conductive layer mainly made of indium oxide is formed on an organic polymer molded article, in which the transparent conductive layer is crystalline and amorphous. The present invention is a transparent conductive laminate characterized by being a film with mixed qualities and having a crystallinity of 1 to 80%.

The present invention also provides a method for producing a conductive laminate in which a transparent conductive layer mainly composed of indium oxide is formed on an organic polymer molded product, in which first the organic polymer molded product mainly contains indium oxide. The extinction coefficient at a wavelength of 550 nm is 1.0 x 10-4 to 3.9 x 10-' (physiology),
Specific resistance is 4.0×10-' ~ 1.4X10-'Ω・C
This is a method for producing a transparent conductive laminate, characterized by forming a 1n layer and then heat-treating the core layer.

As a result of detailed analysis of the film structure of the transparent conductive layer using a transmission electron microscope, the present inventors found that there is a significant relationship between the crystallinity of the film and the bending resistance.

Here, the crystallinity represents the ratio of the area of the crystalline part in a transmission electron micrograph, and is defined by the following formula.

Crystallinity (%) = [Crystalline area / (Crystalline area + Amorphous area)) x 100 In other words, a film with a crystallinity of 100% has extremely poor bending resistance, but surprisingly It was found that when the degree of crystallinity was 80% or less, the bending resistance was rapidly improved. Presumably, the amorphous portion buffers the strain at the grain boundaries. It is surprising that a buffering effect appears when the amorphous portion is about 20%.

On the other hand, it was found that films with less than 1% crystalline portion also had poor bending resistance. It is thought that such a film is a film that has been insufficiently heat-treated and has residual distortion immediately after sputtering.

As described above, the film of the present invention is a film in which crystalline portions and amorphous portions coexist, and the degree of crystallinity is 1 to 80%.

The organic polymer compound constituting the beaten polymer molded product in the present invention is not particularly limited as long as it is a transparent organic polymer compound that has heat resistance, but usually has a heat resistance of 1.
00°C or higher, preferably 130°C or higher, such as polyimide, polyethersulfone, polysulfone, polyparabanic acid, polyhydantoin, polyarylate, polyethylene terephthalate, polyethylene-2,6-naphthalenedicarboxy Examples include polyester resins such as polyester, polydiallyl phthalate, and polycarbonate, aromatic polyamides, and cellulose triacetate.

Of course, these can be used as homopolymers, copolymers, alone or in blends.

The shape of the molded product of the organic polymer compound is not particularly limited, but sheet-like or film-like products are usually preferred, and among them, film-like products can be rolled up and can be continuously produced. Therefore, it is particularly preferable. Furthermore, when a film-like material is used,
The thickness of the film is preferably 6 to 500 μm, more preferably 12 to 200 μm.

Pigments may be added to these films or sheets to the extent that transparency is not impaired, or surface treatments such as sand matting may be applied.

Further, these films or sheets may be used alone or in a laminated manner.

Furthermore, in order to improve the adhesion with the transparent conductive layer,
An intermediate layer may be formed on the organic polymer molded product before forming the transparent conductive layer. As the intermediate layer, a layer produced by hydrolysis of an organometallic compound such as an organosilicon compound, a titanium alkyl ester, or a zirconium alkyl ester is preferably used. The intermediate layer may have a multilayer structure.

The intermediate layer is coated onto the organic polymer molding, dried, and cured by heating, ion bombardment, or radiation such as ultraviolet rays, β rays, and γ rays.

For coating the intermediate layer, a known coating machine such as a doctor knife, bar coater, gravure roll coater, curtain coater, knife coater, etc. may be used depending on the shape and properties of the transparent organic polymer molded product and the coating solution. Coating methods, spray methods, dipping methods, etc. are used.

The thickness of the intermediate layer is preferably 100 to 1,000, particularly preferably 200 to 900.

If it is less than 100λ, a continuous layer is not formed, so there is no effect of improving adhesion or the like.

On the other hand, if the number exceeds 1,000 people, it is not preferable because cranking or peeling may occur.

In addition, the conductive laminate of the present invention mainly includes a protective layer on a transparent conductive layer containing indium oxide for the purpose of improving scratch resistance or improving adhesion with other coating layers. may be stacked.

Such protective layers include Ti0z, Snow, Si
o, , Zr0z, transparent oxides such as ZnO, Si□
Nitrides such as N4, TiN, transparent organic compounds such as acrylonitrile resin, styrene resin, acrylate resin, polyester resin, cyanoethyl Hojo tin such as cyanoethylated pullulan, organosilicon compounds, titanium alkyl esters, zirconium alkyls, etc. Organometallic compounds such as esters can be used.

The thickness of such a protective layer can be set arbitrarily within a range that does not deteriorate the characteristics of the transparent conductive layer.

Further, the conductive laminate of the present invention may have a structure in which transparent conductive layers are laminated on both sides of the organic polymer molded material via an intermediate layer as necessary, or a transparent conductive layer may be laminated on one side of the organic polymer molded material as necessary. For the purpose of improving adhesion, surface hardness, optical properties, etc. without impairing transparency on the side opposite to the side on which the transparent conductive layer is laminated in a structure in which transparent conductive layers are laminated via an intermediate layer according to For example, a layer similar to the above-mentioned intermediate layer or protective layer, an oxide layer, a nitride layer, a sulfide layer, a carbide layer, or an organic layer may be provided.

The film of the present invention has an absorption coefficient of 1.0 at a wavelength of 550 nm that mainly contains indium oxide on an organic polymer molded product.
x10-4 to 3.9 I can do it.

Extinction coefficient is 4X10" (resistivity increases at 3 or higher, 5)
If the thickness is more than XIQ-''Ω·cm, crystal growth tends to occur, resulting in a film with a crystallinity of 100%, resulting in poor bending resistance.

In addition, the extinction coefficient is less than 1.0 × 10-' (in)
Anti-force 4. ox i o-'Ω·cm Those without grooves have poor conductivity after heat treatment.

Here, the extinction coefficient a is the wavelength 550 measured with an integrating sphere.
Transmittance T (%) and reflectance R including the substrate at nm
(%), the absorption rate B (%) by the organic polymer molded material that is the substrate, and the film thickness t (person) of the ITO film.

a = (1/l)log (100-R-B)/T
[Person-1] The extinction coefficient of the ITO film with a light absorption rate of 2 to 30%, which was previously proposed by the present inventors, is based on the ITO film thickness of approximately 2%.
00 people, 5.3X10-' ~ 9.6X10-' [
Person-1].

The method of the present invention is not limited to the sputtering method, but can also be applied to other known thin film forming methods, such as the ion blating method.

In the sputtering method for forming a layer mainly containing indium oxide, an alloy containing indium as a main component or a sintered body containing indium oxide as a main component can be used as a target.

In the former, an inert gas such as argon and a reactive gas such as oxygen gas are introduced into a vacuum chamber to perform reactive sputtering. In the latter case, sputtering is performed using an inert gas such as argon alone or a mixture of an inert gas such as argon and a trace amount of a reactive gas such as oxygen gas. As the sputtering method, known methods such as direct current or high frequency bipolar sputtering, direct current or high frequency magnetron sputtering, and ion beam sputtering can be applied. Among these, the magnetron method is preferable because it causes less plasma impact on the substrate and allows high-speed film formation.

Further, in the ion blating method, an alloy containing indium as a main component or a molded product containing indium oxide as a main component can be used.

In the former, reactive ion blating is performed by introducing a reactive gas such as oxygen gas alone or a mixed gas of a reactive gas and an inert gas such as argon into a vacuum chamber. In the latter case, an inert gas such as argon alone or a mixture of an inert gas and a reactive gas such as oxygen gas is used.

Here, the ion blating method refers to evaporated particles and/or
Alternatively, film formation is performed while part of the introduced gas is ionized, and methods for ionization include applying direct current, alternating current, high frequency, microwave, etc. There is also a method in which an ionization electrode is provided near the evaporation source and no introduction gas is required.

In either case, the formation conditions must be controlled so that the absorption coefficient and resistivity of the layer mainly containing indium oxide, which is formed by sputtering, ion blating, etc., reach desired values. Formation conditions vary depending on the device.

For example, in the sputtering method, the deposition rate (i.e., input power) can be varied under a constant oxygen partial pressure to determine the characteristics of the deposited film, or the deposition conditions can be determined by keeping the input power constant and determining the oxygen concentration. There are methods to examine the characteristics of a film deposited by varying the pressure.

In short, in the equipment used, the absorption coefficient of the layer containing indium oxide is 1.0x10-s to 3.9x10-' (in phase), and the specific resistance is 4.0x10-4 to 1.4x10. -3
The formation conditions are experimentally determined so that the layer becomes Ω·cm, and the formation conditions are controlled so that the absorption coefficient and specific resistance of the layer containing indium oxide have the above values.

The transparent conductive layer used in the present invention is a layer mainly containing indium oxide. The indium oxide layer is originally a transparent electrical insulator, but it becomes a semiconductor when it contains trace amounts of impurities, or when there is a slight oxygen deficiency. Preferred semiconductor metal oxides include, for example, indium oxide containing tin or fluorine as an impurity. Particularly preferably, tin oxide is 2 to 20
% by weight of indium oxide.

The thickness of the transparent conductive layer mainly containing indium oxide used in the present invention is 50 Å in order to obtain sufficient conductivity.
It is preferably at least 100 Å, more preferably at least 100 Å.

In addition, in order to obtain a film with sufficiently high transparency, 500
The thickness is preferably Å or less, more preferably 400 Å or less.

In the present invention, a layer containing mainly indium oxide is formed on an organic polymer molded article via an intermediate layer if necessary by a sputtering method, an ion blating method, etc., and then a heat treatment is performed.

The heat treatment atmosphere is not particularly limited. An oxygen atmosphere, an inert gas atmosphere, or a reducing gas atmosphere can be selected as necessary.

Further, the heating temperature is preferably 100 to 250°C, particularly preferably 130 to 200°C. If the temperature is less than 100''C, the bending resistance cannot be improved.

On the other hand, if the temperature exceeds 250°C, deformation or cracks will occur in the organic polymer molded article, which is not preferable.

Note that the heat treatment time is determined experimentally depending on the heating temperature, layer composition, and the like.

The conductive laminate obtained by the present invention is not only suitable for transparent touch panels and electroluminescent electrodes, but also for electrophotography, antistatic materials, surface heating elements, solid-state displays, optical memories, photoelectric conversion elements, optical It has a wide range of uses, including communications, optical information processing, and solar energy utilization materials.

[Effect]

As mentioned above, the JTO film formed by the conventional sputtering method has a big problem in practical use.

In order to investigate the cause of disconnection in the transparent conductive layer, the present inventors
When the film structure of the transparent conductive layer was analyzed using a transmission electron microscope, it was found that those with clear grain boundaries had poor bending resistance and were more likely to break. It is presumed that new strain occurs in the transparent conductive layer as the crystal grows, resulting in poor bending resistance. In addition, since the film immediately after sputtering without heat treatment has poor bending resistance,
It is presumed that distortions from the film deposition process remain.

In the present invention, the extinction coefficient of the film immediately after sputtering is 1.0.
If a layer with a specific resistance of 4.0X10-4 to 1.4X10-' Ω・1 is formed with a specific resistance of The degree of crystallinity can be controlled to 1 to 80%, and the bending resistance can be significantly improved.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Examples 1 to 3 and Comparative Examples 1 to 2 A mixed alcoholic solution of organosilicon compounds such as butanol and isopropanol (fi degree 0.6% by weight) was coated on both sides of a 75 μm thick polyethylene terephthalate film using a bar coater. Dry at ℃ for 1 minute. The film thickness after drying was 300.

The film was fixed to a substrate holder in a DC magnetron sputtering device, and the vacuum layer was evacuated to a vacuum level of 2×10-' Torr. After that, Ar/Ot mixed gas (02
25%) into the tank, and the vacuum level was set to 4 x 10-'Tor.
After keeping at r, r n/S n alloy (Sn 5 wt%
), indium tin oxide films having the extinction coefficients and specific resistances of Examples 1 to 3 and Comparative Example 1 were formed by reactive sputtering at varying deposition rates.

These samples were heat-treated in a hot-air dryer maintained at 150"C, and the crystallinity, specific resistance, bending resistance, and degree of wire breakage after bonding with the light-emitting layer were examined after the heat treatment. .

As Comparative Example 2, the characteristics of a sample that was not subjected to heat treatment were also investigated in the same manner.

In addition, the bending resistance is determined by using a diameter of 5 mm with the transparent conductive layer on the outside.
It is defined as the ratio R/R of the resistance value R after being repeatedly deformed 10 times along the circumference of a round bar of φ and returning to its original state, and the resistance value R0 before deformation.

The results are shown in Table 1.

The transparent conductive laminate of the present invention had excellent bending resistance, and there was no disconnection after bonding it to the light emitting layer.

Table 1 [Effects of the Invention] The present invention has produced an IT-based laminate using sputtering method, ion blating method, etc., which has extremely excellent durability and reliability and can be fully used for transparent touch panels and electroluminescence. can be provided.

Patent applicant Teijin Co., Ltd. Agent: Patent Attorney Takashi Shirai

Claims (3)

[Claims] (1) In a conductive laminate in which a transparent conductive layer mainly made of indium oxide is formed on an organic polymer molded article, the transparent conductive layer is a mixed crystalline and amorphous film, and A transparent conductive laminate, characterized in that the degree of oxidation is 1 to 80%. (2) In the method for manufacturing a conductive laminate in which a transparent conductive layer mainly composed of indium oxide is formed on an organic polymer molded article, first, a transparent conductive layer containing mainly indium oxide with a wavelength of 550 nm is formed on the organic polymer molded article. Extinction coefficient is 1.0
×10^-^5 ~ 3.9 × 10^-^5 [Å^-^1]
So, the specific resistance is 4.0×10^-^4~1.4×10^-
A method for producing a transparent conductive laminate, which comprises forming a layer of ^3Ω·cm and then heat-treating the layer. (3) Claim 2, wherein the heat treatment temperature is 100 to 250°C.
The method for manufacturing the transparent conductive laminate described above.