JP2002157929A - Transparent conductive thin film laminated product and its etching method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To pattern a transparent conductive thin film laminated product comprising a transparent, high-refraction factor thin film layer and a transparent metal thin film layer by a fine patterning dry etching method. SOLUTION: The transparent conductive thin film laminated product formed by laminating the transparent, high-refraction factor thin film layer 2 and the transparent metal thin film layer 30 on a transparent substrate 10 is exposed to the gas obtained by decomposing reaction gas with plasma and having the pressure of 10 Pa or below for etching. The transparent conductive thin film laminated product is etched by this etching method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for etching a laminate and a laminate etched by the method, and more particularly to a method for etching a laminate with a reactive gas and a laminate etched by the method. It is about the body.

[0002]

2. Description of the Related Art A transparent conductive thin film is a thin film having conductivity despite being transparent, and a typical example thereof is a thin film made of an oxide of indium and tin (ITO). Its uses are wide. The main applications are for transparent electrodes of display panels and for shielding electromagnetic waves. The transparent electrode is a surface electrode of the viewing portion of the display panel, and is a liquid crystal display (LC
D), electroluminescence (EL) display, plasma display panel (PDP), etc.
Widely used. Recently, an organic electroluminescence (OEL) display and a field emission display (FED) have attracted attention as one of next-generation displays.

In recent years, the need for a large and small display panel has been greatly increased. To achieve this, it is necessary to reduce the power consumption of the display element. For this purpose, it is effective to develop a transparent electrode having a low resistance value while maintaining the visible light transmittance. In particular, organic electroluminescent elements, which are being developed recently, are of a self-luminous type and are mainly developed for small portable terminals. Therefore, there is great expectation for lowering the resistance of transparent electrodes. In addition, a plasma display panel (PDP) that is currently spreading on the market and a field emission display (FE) that is being developed as a next-generation display
D), liquid crystal displays (LC
Regarding D), there is great expectation for the development of low-resistance transparent electrodes from the viewpoint of reducing power consumption. Further, as for LCDs, particularly in the case of a simple matrix drive system, as the resolution increases, there arises a problem that if the resistance of the transparent electrode is not sufficiently reduced, the display condition for each pixel will vary, so that the transparent electrode Is an important development issue.

[0004] In the case of a transparent electrode using ITO or the like, a heat treatment after film formation is performed in order to realize a low resistance. Processing temperatures range up to several hundred degrees Celsius. However, in this method, it is difficult to mass-produce a material having sufficient characteristics with good reproducibility. Also,
When targeting a small portable terminal, it is necessary to reduce the weight of the transparent electrode itself. In order to reduce the weight of the transparent electrode, it is effective to reduce the weight of the base. For this reason, glass has conventionally been mainly used, but recently, a polymer molded article has been used.

[0005] Polymer molded articles generally have poor heat resistance.
For this reason, the heat treatment performed after the formation of the thin film in order to reduce the resistance of ITO or the like cannot be performed. As a means for realizing a low-resistance transparent electrode without performing heat treatment, use of a transparent conductive thin film laminate is effective. The transparent conductive thin film laminate is one in which a metal thin film having excellent conductivity is sandwiched between transparent high refractive index thin films. The conductivity of the transparent conductive thin film laminate mainly depends on the conductivity of the transparent metal thin film layer, and a high conductivity that cannot be realized by the conventional transparent conductive thin film can be obtained. This transparent conductive thin film laminate,
By selecting the material and film thickness of each thin film layer, it is very useful because it can be designed so as to have optimal optical and electrical characteristics according to the application.

[0006] The display surface is usually a collection of patterned, fine pixels. Each pixel emits light independently to display various characters and images. The transparent electrode used must also be patterned according to the target pixel size. The patterning shape required for the transparent electrode depends on the display driving method. For example, when driven by the simple matrix method, the pattern is often linearly formed, and when driven by the thin film transistor (TFT) method, the pixels are formed in a grid pattern for each pixel. Many.

Conventionally, IT used as a transparent electrode
O is also usually used after patterning as described above. The patterning method is roughly classified into a wet method and a drying method. Generally, a wet method is used. In the wet method, for example, patterning is performed by preparing an ITO film formed on the entire surface and dissolving unnecessary portions using hydrochloric acid. However, in the case of a laminate, the etching rate is usually different depending on each layer. For this reason, it is very difficult to perform etching so that the end faces of the stacked layers after etching are aligned, and the thickness of the layers becomes uneven. As a result, when the display element is manufactured, the display state becomes non-uniform.

As a means for solving the above-mentioned problem, a method using a dry etching method is effective. Gases used for dry etching include hydrogen iodide gas (HI gas), hydrogen bromide gas, chlorine gas, methane gas,
Methanol gas or the like is used. Among them, hydrogen iodide gas can obtain the highest etching rate,
Further, the most stable etching can be performed without leaving any residue on the substrate. The dry etching of ITO is performed by using a capacitively coupled 13.56 MHz high frequency power supply, setting a substrate to be etched on the application electrode, and applying a self-bias voltage formed by discharge to generate plasma. The RIE (Reactive Ion Etching) method, in which generated ions are guided to a substrate to promote a chemical reaction to advance an etching reaction, is mainly used.

When HI gas is used for dry etching of ITO, an etching rate exceeding 100 nm / min can be achieved by using an RIE type apparatus, and a clean etching process can be performed without leaving any residue on a substrate. Is known and can be said to be an excellent etching method. The dry etching of ITO using HI has been introduced in many documents so far and is well known. For example, J. Electrochem. Soc., Vol.
136, No. 6, June 1989, pp. 1839, describes a dry etching characteristic of ITO using HI. December 1996
Sputtering & Plasma Processes Vo held on the 11th
In l.11 No.5, there are many reports on dry etching of ITO using HI gas. Also,
There is also disclosed a method of using not only HI gas alone for dry etching of ITO but also mixing other gases. For example, Japanese Patent Application Laid-Open No. 5-251400 discloses a method in which an HI gas is mixed with an etching species or a hydrogen gas. In Japanese Patent Application Laid-Open No. 6-151380, A
Although it is a method of etching together with a thin film, a method using a mixed gas with BCl3 gas is disclosed. Further, Japanese Patent Application Laid-Open No. 8-97190 discloses a dry etching method of ITO by mixing with Ar gas.

As a gas used for dry etching of ITO, not only HI gas but also etching with another gas is being studied. A method using chlorine gas, a method using hydrogen bromide (HBr) gas, and the like have been proposed. The contents published in the May 1996 issue of Solid State Technology include a report on the etching of ITO using HBr gas using ICP discharge and a report from Lam Resarch Corp.
It is made by. However, similar to the HI gas, these gases have a problem that a residue remains on the inner wall of the chamber.

Further, as a gas used for dry etching of ITO, a method of mixing methane (CH ₄ ) gas with hydrogen or chlorine (Cl ₂ ) has been proposed. Also in Sputtering & Plasma Processes Vol. 11 No. 5 described above, a dry etching method of ITO using methane gas is disclosed. When using methane gas,
There is a problem that by-products remain on the substrate to be etched. As described above, it is considered that it is most preferable to use a hydrogen iodide gas for the dry etching method of ITO, but it is also necessary to use a bromine-based gas such as hydrogen bromide and a chlorine-based gas such as hydrogen chloride. Is also possible.
However, no effective gas has been found for dry etching of the Ag thin film.

[0012]

The problem to be solved by the present invention is to provide a transparent conductive thin film laminate comprising a transparent high refractive index thin film layer and a transparent metal thin film layer by a dry etching method using a reactive gas. This enables fine patterning.

[0013]

The object of the present invention can be solved by the invention specified by the following items. (1) A transparent high refractive index thin film layer (a) on a transparent substrate (A)
And etching a transparent conductive film laminate obtained by laminating the transparent metal thin film layer (b) with a gas having a pressure of 10 Pa or less, which is obtained by decomposing a reactive gas by plasma. (2) the reactive gas is hydrogen iodide gas, methyl iodide gas, methylene iodide gas, methyl trifluoride iodide gas;
It is a volatile gas whose main component is a gas selected from hydrogen bromide gas, methyl bromide gas, methylene bromide gas, chlorine gas, hydrogen chloride gas, boron trichloride gas or nitrogen trifluoride gas. The etching method according to (1). (3) A transparent conductive thin film laminate etched by the method according to (1) or (2). (4) The transparent conductive thin film laminate according to (3), wherein the ends of the respective layers in the laminated cross section after being linearly etched coincide with each other with an accuracy within 20 μm. (5) The transparent conductive thin film laminate according to (3), wherein the matching accuracy is within 10 μm. (6) The transparent conductive thin film laminate according to (3), wherein the matching accuracy is within 5 μm. (7) A transparent high refractive index thin film layer (a) on a transparent substrate (A)
And A / a / b / a or A / a / b / a
a / b / a / b / a or A / a / b / a / b / a / b
The transparent conductive thin film laminate according to any one of (3) to (6), wherein the transparent conductive thin film laminate is formed by laminating in the order of / a. (8) The transparent conductive thin film laminate according to any one of (3) to (7), wherein the transparent substrate (A) is a polymer molded body. (9) The transparent conductive thin film laminate according to any one of (3) to (7), wherein the transparent substrate (A) is glass. (10) The transparent high refractive index thin film layer (a) is a thin film layer mainly composed of indium oxide, a thin film layer mainly composed of zinc oxide, or a thin film layer mainly composed of titanium oxide. The transparent conductive thin film laminate according to any one of (3) to (9). (11) The transparent conductive thin film laminate according to any one of (3) to (10), wherein the transparent metal thin film layer (b) is a silver or silver alloy thin film layer. (12) The transparent conductive thin film laminate according to (11), wherein the silver alloy is an alloy of silver and at least one metal selected from gold, palladium, and copper. (13) A transparent electrode using the transparent conductive thin film laminate according to any one of (3) to (12).

[0014]

[Transparent Substrate] The transparent substrate used in the present invention includes a transparent polymer molded substrate and a transparent glass substrate. The transparent polymer molded substrate is suitably used because it is lighter, harder to break, and more easily bent than a transparent glass substrate.

As the transparent substrate, those in a film state and a plate state are mainly used, and it is preferable that they have excellent transparency and sufficient mechanical strength according to the use.
Here, “excellent in transparency” means that the luminous transmittance is 40% or more in the thickness in the used state. Further, an antireflection layer or an antiglare layer may be formed on the surface opposite to the main surface of the transparent polymer molded substrate.

The transparent substrate in the form of a film is mainly a transparent polymer molded substrate. Specific examples of the transparent polymer molded substrate include polyimide, polysulfone (PSF), polyethersulfone (PES), polyethylene terephthalate (PET), and polymethyl methacrylate (PMM).
A), polycarbonate (PC), polyetheretherketone (PEEK), polypropylene (PP), triacetylcellulose (TAC) and the like. Among them, polycarbonate (PC) and polyethersulfone (PES) are particularly preferably used.

The thickness of the transparent polymer molded base film is not particularly limited. Usually, it is about 20 to 500 μm. The plate-shaped transparent substrate is mainly a transparent polymer molded substrate and a transparent glass substrate. An example of a preferable material for the plate-shaped transparent polymer molded substrate is polymethyl methacrylate (PMMA).
And other acrylic resins, polycarbonate resins and the like, but are not limited to these resins. Among them, PMMA can be suitably used because of its high transparency in a wide wavelength region and high mechanical strength.

The transparent polymer molded article is often provided with a hard coat layer for the purpose of increasing the surface hardness or adhesion. A transparent glass substrate having almost no surface warpage or scratches is generally used. When the active driving element is formed on the glass, alkali-eluting from the glass may greatly affect the performance of the active element. Therefore, non-alkali glass is used. In other cases, inexpensive soda-lime glass is used. The manufacturing method of the glass plate is
There are a float method, a download method, a fusion method, and the like. Alkali-free glass (white plate glass) is produced by a download method or a fusion method, and soda lime glass (blue plate glass) is produced by a float method.

The thickness of the plate-shaped transparent substrate is not particularly limited as long as it has sufficient mechanical strength and rigidity for maintaining flatness without sagging. Usually, it is about 0.5 to 10 mm. Further, a layer for improving gas barrier properties may be formed on the surface of the transparent substrate. For the purpose of improving gas barrier properties, ethylene vinyl acetate compounds (EVA), polyvinyl acetate compounds (PVA), and the like are generally used, but are not limited thereto.

[Transparent high-refractive-index thin film layer] The material used for the transparent high-refractive-index thin film layer preferably has as high a transparency as possible. Here, “excellent in transparency” means that when a thin film having a thickness of about 100 nm is formed, the luminous transmittance of the thin film is 60% or more. The high-refractive-index material is a material having a refractive index for light of 550 nm of 1.4 or more. These may be mixed with impurities depending on the application.

Examples of materials that can be suitably used for the transparent high refractive index thin film layer include oxides of indium and tin (ITO) and oxides of cadmium and tin (CT
O), aluminum oxide (Al ₂ O ₃ ), zinc oxide (Zn)
O ₃ ), oxides of zinc and aluminum (AZO), magnesium oxide (MgO), thorium oxide (Th
O ₂ ), tin oxide (SnO ₂ ), lanthanum oxide (La
O ₂ ), silicon oxide (SiO ₂ ), indium oxide (I
n ₂ O _3), niobium oxide (Nb ₂ O _3), antimony oxide (Sb ₂ O _3), zirconium oxide (ZrO _2), cesium oxide (CeO _2), titanium oxide (TiO _2), bismuth oxide (Bi ₂ O ₃ ).

Further, a transparent high refractive index sulfide may be used. Specific examples include zinc sulfide (ZnS), cadmium sulfide (CdS), and antimony sulfide (Sb ₂ S ₃ ). Among transparent high refractive index thin film materials,
ITO, TiO ₂ and AZO are particularly preferred. ITO and AZO have conductivity, and the refractive index in the visible region is as high as about 2.0, and has little absorption in the visible region. TiO ₂ is an insulator and has a slight absorption in the visible region, but has a large refractive index for visible light of about 2.3.

The transparent electrode according to the present invention has two transparent high refractive index thin film layers (a). The transparent high refractive index thin film layer (a) located on the outermost surface is formed, for example, when the element is manufactured. When an organic electroluminescence device was manufactured,
Since it is in direct contact with the organic layer, the magnitude of the electric resistance determines the emission luminance. For this reason, the material used for the transparent high refractive index thin film layer (a) located on the outermost surface preferably has a low specific resistance, and usually, ITO or AZO is suitably used. The thickness of the transparent high-refractive-index thin film layer is determined in consideration of the transmittance and electric conductivity of the entire transparent electrode.
Usually, it is about 0.5 to 100 nm.

[Transparent Metal Thin Film] As the material of the transparent metal thin film layer used in the present invention, a material having good electrical conductivity as much as possible and high transparency in a thin film state is preferable. Here, good electrical conductivity means that the specific resistance is 1 × 10
⁻⁵ (Ω · cm) or less. In addition, high transparency means that the average luminous transmittance at the target film thickness is 40%.
% Or more. In the present invention, silver or a silver alloy is preferably used. , Silver has a specific resistance of 1.
It is 59 × 10 ⁻⁶ (Ω · cm), and is most preferably used because it has the best electrical conductivity among all materials and the visible light transmittance of the thin film. However, silver has a problem that it lacks stability when formed into a thin film and is susceptible to sulfidation and chlorination. Therefore, to increase stability,
Instead of silver, an alloy of silver and gold, an alloy of silver and copper, an alloy of silver and palladium, an alloy of silver and copper and palladium, an alloy of silver and platinum, or the like may be used. Further, gold or copper may be used. The thickness of the transparent metal thin film layer is determined in consideration of the transparency and electric conductivity of the entire transparent electrode. Usually 0.5
About 100 nm.

[Film Forming Method] The transparent high refractive index thin film layer, the transparent metal thin film layer, and the gas barrier layer may be formed by a conventionally known method such as a vacuum deposition method, an ion plating method, and a sputtering method.

For forming the transparent high-refractive-index thin film layer, an ion plating method or a sputtering method is suitably used. In the ion plating method, a desired metal or sintered body is resistance-heated in a reaction gas plasma or heated by an electron beam to perform vacuum deposition.
In the sputtering method, using a desired metal or sintered body as a target, using an inert gas such as argon or neon as a sputtering gas, and adding a gas necessary for the reaction,
Perform sputtering. For example, when an ITO thin film is formed, DC magnetron sputtering is performed in oxygen gas using an oxide of indium and tin as a sputtering target.

For the transparent metal thin film layer, a vacuum evaporation method or a sputtering method is suitably used. In the vacuum evaporation method, a transparent metal thin film can be easily formed by using a desired metal as an evaporation source and performing heating evaporation by resistance heating, electron beam heating, or the like. In the case of using a sputtering method, a transparent metal thin film is formed by using a desired metal material as a target, using an inert gas such as argon or neon as a sputtering gas, and using a direct current sputtering method or a high frequency sputtering method. be able to. In order to increase the deposition rate, a DC magnetron sputtering method or a high-frequency magnetron sputtering method is often used.

[Structure] The structure of the transparent conductive thin film of the present invention is a repetitive laminate of a transparent high refractive index thin film layer (a) and a transparent metal thin film layer (b), and is formed on a transparent substrate (A). Is done. Specific cross-sectional configurations are A / a / b / a, A
/ A / b / a / b / a, A / a / b / a / b / a / b /
a and the like. Each of the a and b layers may consist of substantially two or more layers. Further, a layer may be formed in the middle of the A layer and the a layer, in the middle of the a layer and the b layer, on the surface of the a layer located on the outermost surface, or the like for the purpose of increasing adhesion or increasing the gas barrier property. . FIG. 1 is a cross-sectional view showing an example of the transparent conductive thin film laminate according to the present invention. 10: A transparent high-refractive-index thin film layer (a) and 30: a transparent metal thin-film layer (b) are formed on the transparent substrate (A) in an A / a / b / a configuration.

[Patterning] Normally, a plurality of transparent electrodes for a device driven by a simple matrix system are formed in a linear shape having a width and at a certain interval in parallel. Although the width of the transparent conductive thin film forming portion is not particularly specified, it is usually 20 to 2000 μm. Also, there is no particular designation for the width of the portion where the transparent conductive thin film is not formed. Usually, it is 1 to 3000 μm. For example, in the case of an organic EL element, this transparent electrode becomes an anode. In the case of an LCD element, two transparent electrodes are combined and arranged so that the respective transparent electrodes cross each other. If you specify one with one transparent electrode and one with another transparent electrode,
A voltage can be applied to the intersection.

In the case of driving by an active matrix driving method, an active driving element is formed on a transparent electrode substrate. A transparent electrode as a pixel electrode is formed for each drive element. The size and shape of the pixel electrode are usually rectangles each having a length of 20 to 500 μm on one side, and in many cases, a part of the shape is applied to arrange driving elements. FIG. 2 shows an example of a patterning shape according to the present invention. Reference numeral 40 denotes a portion where a transparent conductive thin film layer is formed, and reference numeral 50 denotes a portion where no transparent conductive thin film is formed.

In the present invention, when the laminated body is patterned by etching, the coincidence of the end faces of each laminated layer after etching is not significantly impaired. Here, the end-face matching accuracy is defined as a distance between the two end faces when two of the plurality of stacked layers whose end faces are farthest apart from each other are selected. It is determined that the smaller the value is, the higher the end face matching accuracy is. The preferred matching accuracy is within 20 μm, more preferably within 10 μm, even more preferably within 5 μm.

[Dry Etching Method] The dry etching method is a method of performing etching using gas molecules which have been brought into a high energy state by high frequency plasma or the like. Usually, a necessary part is covered with a mask, and an unnecessary part is removed. As a mask, a photoresist is used, or a tape is used for simple operation. In the case of using a photoresist, first, a photoresist is applied to the entire surface, and ultraviolet light is applied to portions other than the portion where the mask is formed. afterwards,
The UV-irradiated portion is removed by development. After completion of the etching process, the resist is removed using an alkaline solution. If a tape is used, it may be peeled off.

The dry etching method disclosed by the present invention can be applied to an RIE type and an ICP type etching apparatus in which a high frequency electric field of 13.56 MHz is applied. Further, it can be used for an ECR type device and the like. In the case of the RIE type device,
Applied electrode (cathode electrode) and counter electrode (anode electrode)
Although a device using a device in which a discharge is formed is usually used, but when the counter electrode is grounded,
Usually, the substrate is placed on the side of the application electrode. Further, when a bias voltage (which may be applied by a high frequency) is applied to the counter electrode,
A substrate may be provided on the counter electrode side. The frequency of an applied electrode used for dry etching of an indium compound thin film such as an RIE-type ITO disclosed in the present invention is 5 MHz or more and 200 MHz or less, and covers a range from a so-called RF discharge to a VHF discharge. Also, I
When the CP-type discharge is used, a frequency included in a range of 1 MHz to 100 MHz on the application electrode side is used.

The gas which can be used is, specifically,
Any of hydrogen iodide gas, methyl iodide gas, methylene iodide gas, methyl trifluoride iodide gas, hydrogen bromide gas, methyl bromide gas, methylene bromide gas, chlorine gas, hydrogen chloride gas, and boron trichloride gas It is a volatile gas or the like as a main component. An inert gas such as argon may be added to these.

The dry etching in the present invention is performed at a pressure of 0.001 to 10 Pa. 10
Under a pressure condition higher than Pa, it is possible to etch a transparent high-refractive-index thin film layer of ITO or the like, but it is difficult to etch a transparent metal thin-film layer such as silver. This is because a compound formed by reacting with silver has a low vapor pressure and does not have volatility itself, so that it is necessary to perform etching by sputtering. In order to cause this sputtering phenomenon, a low operating pressure is required. Therefore, a pressure condition of 10 Pa or less is preferable.

FIG. 3 shows a diagram of the dry etching apparatus used in the present invention. The device of the present invention comprises a normal RIE device. Specifically, a chemical dry pump 70 for exhaust and a turbo molecular pump 80 are provided in the etching chamber 60.
And a system capable of obtaining a high vacuum up to 0.002 Pa or less. Since the electrodes are of the RIE type, they are composed of parallel plate electrodes, and 13.56 MHz.
application electrode 90 capable of supplying high-frequency power of z
And a counter electrode 100 that is grounded. A substrate including the substrate 110 to be etched can be provided on the upper surface of the application electrode. In the present system, a glass plate and a sputter target I
An object to be etched was placed on the TO plate. Further, the apparatus used in the present invention is equipped with an external heater 120, a mass flow controller 130, a partial pressure gauge sensor 140, and a partial pressure gauge main body 150, and the steam pressure in the chamber corresponds to a mass number of 18. It can be measured as a pressure component. The measured pressure can be read by the partial pressure gauge, but the measurable pressure range is from 0.000001 Pa to 0.1 Pa.

The etching gas is supplied from the counter electrode via the mass flow controller 130. Using this apparatus, HI gas 50 sccm,
Under the conditions of a pressure of 6.5 Pa and an RF output of 100 W, when a 1000 nm-thick ITO thin film placed on a glass substrate is etched, 70 n in a temperature range from room temperature to 80 ° C.
An etching rate of m / sec to 100 nm / sec is obtained.

[Analysis Method] The method of analyzing a laminate in the present invention is as follows. The atomic composition of the thin film layer surface of the transparent conductive thin film laminate is determined by Auger electron spectroscopy (AES), X-ray fluorescence (XRF), X-ray microanalysis (X
MA), charged particle excited X-ray analysis (RBS), X-ray photoelectron spectroscopy (XPS), vacuum ultraviolet photoelectron spectroscopy (UP
S), infrared absorption spectroscopy (IR), Raman spectroscopy, secondary ion mass spectroscopy (SIMS), low energy ion scattering spectroscopy (ISS) and the like. The atomic composition and thickness of the film are determined by Auger electron spectroscopy (AES) or 2
It can be checked by performing secondary ion mass spectrometry (SIMS) in the depth direction.

The structure and the state of each layer of the transparent conductive thin film laminate were measured by an optical microscope on a cross section and a scanning electron microscope (SE).
M) Measurement, which can be examined using transmission electron microscope measurement (TEM). The coincidence accuracy of each layer at the edge after etching can be easily checked by optical microscope measurement, and more specifically, optical microscope measurement of a cross section, scanning electron microscope (SEM) measurement, transmission electron microscope measurement (TE
M). The optical characteristics may be examined using conventionally known means. For example, the transmittance may be measured by a spectroscope. The electrical characteristics may be examined using conventionally known means. For example, using the four-terminal method,
What is necessary is just to measure the sheet resistance.

The structure of the transparent conductive thin film laminate and the state of each layer were determined by measuring the cross section with an optical microscope and using a scanning electron microscope (SE).
M) Measurement, which can be examined using transmission electron microscope measurement (TEM). The usefulness of the transparent conductive thin film laminate obtained by the present invention as a transparent electrode can be confirmed by actually producing a display element and examining a display state.

[0041]

EXAMPLES (Example 1) [Preparation of transparent conductive thin film laminate] As a transparent substrate, a glass plate [Soda-lime glass, manufactured by Asahi Glass Co., Ltd., size 50 ×
50 mm square, thickness 1.1 mmt] were prepared, and first, a transparent conductive thin film laminate was formed. Using a DC magnetron sputtering method, a thin film layer (a) made of an oxide of indium and tin and a thin film layer (b) of an alloy of silver and gold are formed on a transparent substrate (A) by A / a [thickness of 40 nm]. / B [9n thickness
m] / a [thickness: 40 nm] to form a transparent electrode. The thin film layer made of an oxide of indium and tin constitutes a transparent high refractive index thin film layer, and the thin film layer of silver and gold alloy constitutes a transparent metal thin film layer. To form a thin film layer composed of an oxide of indium and tin, a target of indium oxide-tin oxide [In ₂ O ₃ : SnO ₂ = 9] was used as a target.
0:10 (weight ratio)], and an argon / oxygen mixed gas (total pressure 266 mPa, oxygen partial pressure 8 m) as a sputtering gas
Pa) was used. In addition, in forming the alloy thin film layer of silver and gold, an alloy of silver and gold [Ag: Au = 9] was used as a target.
5: 5 (weight ratio)], and argon gas (total pressure 266 mPa) was used as a sputtering gas.

The sheet resistance of the produced transparent electrode was 10 Ω /
□, the luminous average transmittance was 88%. Subsequently, a pattern was formed on the transparent conductive thin film laminate. A photoresist [manufactured by Tokyo Ohka Kogyo Co., Ltd., product number TSMR-8900] was applied to the entire surface by spin coating. The coating thickness was about 2 μm. On top of that, an exposure mask [a linear chromium thin film having a shape as shown in FIG. 2 and a width of 500 μm and formed at intervals of 50 μm on a glass plate having a size of 50 mm × 50 mm and a thickness of 1.1 mm) is overlaid. And a mercury ultraviolet lamp [output: 300 W] for 0.5 seconds. Subsequently, it was immersed in an organic alkali developing solution [manufactured by Tokyo Ohka Kogyo Co., Ltd., product number NMD-W], and an ultraviolet irradiation part was removed. The removed part is a transparent conductive thin film laminate,
This is a part that does not need to be laminated.

Subsequently, dry etching was performed to remove unnecessary portions of the transparent conductive thin film laminated layer. The apparatus is an RIE type dry etching apparatus provided with a capacitively coupled high frequency electrode. The substrate on which the transparent conductive thin film laminate was formed was placed on the application electrode, and after evacuation was performed until the pressure became about 0.001 Pa, HI gas was introduced so that the pressure became 0.7 Pa. Etching was performed for minutes. The plasma used for the discharge is 13.56 MHz. Finally, it was immersed in a stripping solution [stripping solution-106 manufactured by Tokyo Ohka Kogyo Co., Ltd.] to remove all the photoresist. A transparent electrode patterned as described above was produced. Regarding the transparent electrode, the direction in which the transparent conductive thin film laminate was formed in a straight line was defined as the X direction, and the direction perpendicular thereto was defined as the Y direction.

[Evaluation] The matching accuracy of each layer at the etched end of the transparent conductive thin film laminate prepared as described above was examined by using a cross-sectional SEM method. .

Example 2 Example 2 was performed in the same manner as in Example 1 except that HBr was used as a reactive gas in the dry etching process, and the reaction was performed for 5 minutes.

(Embodiment 3) In the dry etching process, a mixed gas of HI and argon (H
I: Ar = 90: 10 [pressure ratio]), except that
It carried out similarly to Example 1.

Example 4 [Production of Organic EL Element] An organic EL element was produced using the transparent conductive thin film laminate produced in Example 1 as a transparent electrode. First, a metal mask [50 mm × 50 m
m, a space portion 160 having a thickness of 0.1 mmt and a size of 1000 μm × 500 μm is formed as shown in FIG.
The space between the spaces in the X direction is 1100 μm, and the space in the Y direction is 600 μm. FIG. 4 shows a part of the space. ] Was installed. At this time, the width of the space in the Y direction is made to coincide with the width of the transparent electrode at all locations.

Using a vacuum heating deposition method, N, N′-diphenyl-N, N ′-(3-methylphenyl) -1,1′-biphenyl-4,4′-diamine (abbreviation) is used as a hole transport layer. : TPD) layer [50 nm] was formed. Subsequently, an 8-hydroxyquinoline aluminum (abbreviation: Alq3) layer [5] was formed thereon as a light emitting layer using a vacuum heating evaporation method.
0 nm]. Subsequently, the mask is set to 550 μm in the Y direction.
An organic thin film layer was formed in the same manner as described above. Next, a metal mask [size 50 mm x 50 mm, thickness 0.1 mm
t, a linear space having a width of 1000 μm is formed at intervals of 50 μm] on the organic thin film layer so that the linear direction is the Y direction. A magnesium layer [2 nm] was formed as a cathode using a vacuum heating evaporation method. Finally, wires for passing a current to the transparent electrode and cathode lines, which are anodes, were attached. As described above, an organic electroluminescence device was manufactured.

[Emission Evaluation] A light emission test of the organic electroluminescence device was performed. When a voltage of 10 V was applied while sequentially changing the positions of the anode and the cathode through which current flowed, light was emitted at the position where the selected anode and cathode lines crossed. By selecting a plurality of anodes and cathodes to be used according to the pattern shape to be displayed, it was possible to emit light with a pattern. The light emission state at the edge of the pixel was observed with an optical microscope.

Example 5 Example 5 was carried out in the same manner as in Example 4 except that the transparent conductive thin film prepared in Example 2 was used as a transparent electrode.

Example 6 The same operation as in Example 4 was carried out except that the transparent conductive thin film prepared in Example 3 was used as a transparent electrode.

(Example 7) [Preparation of liquid crystal display element] Two transparent electrodes prepared in Example 1 were prepared, and a liquid crystal display (L) was prepared by the following method.
CD) A device was produced. [Preparation of Color Filter] A color filter was formed on one transparent electrode substrate by an electrodeposition method. The transparent electrode substrate 1 was formed with the color filter, and the transparent electrode substrate 2 was formed without the color filter. A system in which three colors of R, G, and B are alternately arranged on a stripe is adopted. First, an electrodeposition solution was prepared. The polymer resin having a carboxyl group was neutralized with an organic amine to prepare an anionic solution. R, G, B pigments of three colors are separately dispersed therein, and R, G, B
Three kinds of electrodeposition solutions corresponding to three colors were prepared. Subsequently, electrodeposition was performed. The concentration of the pigment was adjusted so that the transmittance was 30% when a color filter having a thickness of 2 μm was formed. First, electrical wiring was performed using a conductive paste on the lead portion of the transparent electrode to be coated on R, and the transparent electrode substrate was immersed in the electrodeposition solution. A counter electrode is provided in advance on the opposite side of the wiring, and the counter electrode is also immersed in the electrodeposition liquid. Thereafter, a voltage was applied between the substrate and the counter electrode to deposit a colored film on the substrate. After washing with water, it was dried. In the same manner, electrodeposition was performed on portions to be coated on G and B. Subsequently, baking was performed at a temperature of 200 ° C. for 60 minutes.

A black matrix was formed in a portion where RGB was not formed. A material for a black mask [a mixture of a black pigment and an ultraviolet curable resin] was applied to the entire surface by a spinner method. Subsequently, ultraviolet rays were irradiated from the back surface [the side opposite to the transparent electrode forming surface] for 30 seconds. It was immersed in an alkali developer for 30 seconds to remove unnecessary portions. Finally, at a temperature of 200 ° C, 60
Bake for a minute.

[Formation of Alignment Film] Subsequently, an alignment film was formed on two transparent electrode substrates. Alignment agent [Nippon Synthetic Rubber,
Polyimide type] by spinner method to a thickness of 300 nm
And baked at a temperature of 180 ° C. for 30 minutes. Thereafter, the surface of the alignment film was rubbed in a certain direction with a roll wound with cotton (rubbing step).

[Preparation of Cell] An empty cell was prepared by combining the two transparent electrode substrates prepared above. Spherical silica [particle size 5 to 6 μm] was spray-sprayed on the transparent electrode forming surface of the transparent electrode substrate 1. Subsequently, an ultraviolet curable resin adhesive was applied to the outer peripheral portion by screen printing. In order to prepare a liquid crystal material injection port, an uncoated portion was made in part. Subsequently, the transparent electrode substrate 2 was overlapped so that the transparent electrode surfaces faced each other, and was irradiated with ultraviolet rays to cure the adhesive. The above steps were performed so that the distance between the substrates was 5 to 6 μm. Subsequently, a liquid crystal material [manufactured by Merck, product number MLC-6075] was injected using a vacuum injection device. Finally, an ultraviolet curable resin sealant was applied to the injection port, cured by ultraviolet light, and the injection port was closed.

[Attaching of Polarizing Film] A polarizing film [manufactured by Nitto Denko] was attached to both sides of the liquid crystal cell prepared above via a transparent adhesive. Regarding the transparent electrode substrate 2,
The direction of vibration of the transmitted light from the polarizing film is made to coincide with the direction of the expected orientation of the liquid crystal molecules. The transmitted light vibration directions of the polarizing film were made to coincide.

[Attaching a Backlight] A backlight unit [manufactured by Enplas] was installed on one side (the transparent electrode substrate 2 side) of the liquid crystal cell prepared above.

[Operation Control Wiring] A TAB film [on the substrate side, copper foils are formed on the stripe at the intervals of 100 μm on the stripe at the electrode take-out portion of the transparent electrode. Copper foils are formed on the stripe at intervals of 3 mm on the outer take-out side by the number of transparent electrodes. The respective copper foils on both sides are electrically connected in a one-to-one correspondence. Was bonded using ACF (manufactured by Hitachi Chemical Co., Ltd.). Thus, an LCD device was manufactured.

[Display Evaluation] A display test of the liquid crystal display device was performed. When a voltage of 1 V was applied while sequentially changing the position of the electrode to which the voltage was applied, light was transmitted at the position where the selected facing electrode line crossed. By selecting a plurality of anodes and cathodes to be used according to the pattern shape to be displayed, it was possible to emit light with a pattern. The light emission state at the edge of the pixel was observed with an optical microscope.

Example 8 Example 8 was carried out in the same manner as in Example 7, except that the transparent conductive thin film prepared in Example 2 was used as the transparent electrode. Example 9 The same operation as in Example 7 was performed except that the transparent conductive thin film prepared in Example 3 was used as the transparent electrode.

(Comparative Example 1) The same operation as in Example 1 was performed except that the etching was performed by a wet method.

In the etching by the wet method, the transparent conductive thin film laminate in a portion that does not need to be formed was immersed in a 20% by weight nitric acid solution for 2 minutes.

Comparative Example 2 An organic EL device was produced and evaluated in the same manner as in Example 2 except that the transparent conductive thin film laminate produced in Comparative Example 1 was used as a transparent electrode.

(Comparative Example 3) An LCD element was prepared and evaluated in the same manner as in Example 7 except that the transparent conductive thin film laminate prepared in Comparative Example 1 was used as a transparent electrode. The above results are shown in Tables 1 to 3.

[0065]

[Table 1]

[0066]

[Table 2]

[0067]

[Table 3]

As can be seen from Table 1, in Examples 1 to 3, the coincidence accuracy of the respective laminated layers at the end portions after the etching is greatly improved. In addition, as can be seen from Table 2, by manufacturing an organic EL element using a transparent conductive thin film laminate having a transparent electrode in which the matching accuracy of each laminated layer is improved, the light emission uniformity of the pixel is greatly improved. Further, as can be seen from Table 3, the uniformity of light emission of the pixels is greatly improved by producing an LCD element using a transparent conductive thin film laminate having a transparent electrode in which the matching accuracy of each laminated layer is improved.

[0069]

According to the present invention, by performing the patterning by the dry etching method, it is possible to provide a transparent conductive thin film laminate in which the pattern accuracy at the end is superior to the conventional one.
By using this, it is possible to provide a display element in which light emission in a pixel is uniform even though the transparent conductive thin film laminate is used as a transparent electrode.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of a transparent electrode.

FIG. 2 is a plan view showing an example of a pattern of a transparent electrode.

FIG. 3 shows a dry etching apparatus.

FIG. 4 is a diagram illustrating an example of an organic molecule deposition mask.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Transparent base material 20 Transparent high refractive index thin film layer 30 Transparent metal thin film layer 40 Transparent conductive thin film forming part 50 Transparent conductive thin film non-forming part 60 Etching chamber 70 Chemical dry pump 80 Turbo molecular pump 90 Applied electrode 100 Counter electrode 110 Etching target Substrate 120 Heater outside chamber 130 Mass flow controller 140 Vacuum gauge sensor 150 Vacuum gauge main body 160 Space

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) H01B 5/14 H01B 5/14 A 5G307 B 5G323 H01L 21/3065 H05B 33/14 A H05B 33/14 33 / 28 33/28 H05K 9/00 V H05K 9/00 G02F 1/1343 // G02F 1/1343 H01L 21/302 FC (72) Inventor Noriyuki Yanagawa 580-32 Nagaura, Sodegaura-shi, Chiba Mitsui Chemicals Co., Ltd. (72) Inventor Mitsuru Sadamoto 580-32 Nagaura, Sodegaura-shi, Chiba F-term within Mitsui Chemicals Co., Ltd. FA01 4F100 AA21B AA21D AA21E AA25B AA25D AA25E AA33B AA33D AA33E AB01C AB01E AB17C AB17E AB24C AB24E AB25C AB25E AB31C AB31E AG00 AG00A AK01A AT00A BA03 B A04 BA05 BA07 BA10A BA10C BA10D BA10E BA13 EH46 EH66 EJ15 EJ58 GB41 JG01 JM02B JM02C JM02D JM02E JN01A JN01B JN01C JN01D JN01E JN18B JN18D JN18E 5E321 AA04 BB23 BB53 BB23 BB23 BB23 BB23 BB23 BB23 BB53 5G323 CA01

Claims (13)

[Claims] 1. A transparent conductive film laminate obtained by laminating a transparent high refractive index thin film layer (a) and a transparent metal thin film layer (b) on a transparent substrate (A), and reacting a reactive gas with plasma. An etching method characterized by performing etching by exposing to a gas having a decomposed pressure of 10 Pa or less. 2. The reactive gas is hydrogen iodide gas, methyl iodide gas, methylene iodide gas, methyl trifluoride iodide gas, hydrogen bromide gas, methyl bromide gas, methylene bromide gas, chlorine gas, hydrogen chloride. The etching method according to claim 1, wherein the etching method is a volatile gas whose main component is a gas selected from a gas, a boron trichloride gas, and a nitrogen trifluoride gas. 3. A transparent conductive thin film laminate etched by the method according to claim 1. 4. The transparent conductive thin-film laminate according to claim 3, wherein the ends of the respective layers in the laminated cross section after being linearly etched coincide with each other with an accuracy within 20 μm. 5. The transparent conductive thin film laminate according to claim 3, wherein the matching accuracy is within 10 μm. 6. The transparent conductive thin film laminate according to claim 3, wherein the matching accuracy is within 5 μm. 7. A transparent high refractive index thin film layer (a) and a transparent metal thin film layer (b) are formed on a transparent substrate (A) by A / a / b / a or A / a / b / a / b / a. Or A / a / b / a / b
7. The transparent conductive thin film laminate according to claim 3, wherein the transparent conductive thin film laminate is formed by laminating in the order of / a / b / a. 8. The transparent conductive thin-film laminate according to claim 3, wherein the transparent substrate (A) is a polymer molded product. 9. The transparent conductive thin film laminate according to claim 3, wherein the transparent substrate (A) is glass. 10. The transparent high-refractive-index thin film layer (a) is a thin film layer mainly made of indium oxide, a thin film layer mainly made of zinc oxide, or a thin film layer mainly made of titanium oxide. The transparent conductive thin film laminate according to any one of claims 3 to 9, wherein: 11. The transparent conductive thin film laminate according to claim 3, wherein the transparent metal thin film layer (b) is a silver or silver alloy thin film layer. 12. The transparent conductive thin film laminate according to claim 11, wherein the silver alloy is an alloy of silver and at least one metal selected from gold, palladium, and copper. 13. A transparent electrode using the transparent conductive thin-film laminate according to claim 3. Description: