JPH08203335A - Transparent conductive film and method for forming the same - Google Patents

Abstract

PURPOSE: To provide a transparent conductive film that is excellent in conductiv ity and in processing stability after being formed and a method for forming the same. CONSTITUTION: This transparent conductive film 1 comprises three layers of films, i.e., high-carrier-mobility thin films 11, 13 made from indium oxide and laminated over a glass substrate 10 and a high-carrier-density thin film 12 made by a thin film of a silver alloy with additions of Mg and Sn, the films 11, 12, 13 being stacked adjacent one another. Large amounts of carriers produced in the high-carrier-density thin film 12 migrate into and move through the high- carrier-mobility thin films at high speed, whereby the conductivity of the entire transparent conductive film can be increased. In addition, the Mg and Sn are excluded from within the high-carrier-density thin film 12 toward the high- carrier-mobility thin films 11, 13 and then produce a hard intermetallic compound in combination with silver elements, thereby preventing physical damage to the transparent conductive film, such as scratches, and peeling of the film after formation of the film and increasing processing stability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent conductive film applied to a transparent electrode of a display device such as a liquid crystal display, an input / output device and a plasma display and a method for forming the same, and more particularly,
The present invention relates to an improvement of a transparent conductive film which is a thin film and has high conductivity and excellent processing stability.

[0002]

2. Description of the Related Art An electrode plate having a transparent electrode for transmitting visible light on a substrate such as glass or plastic film is used as a display electrode for various display devices such as a liquid crystal display or directly input from the display screen of this display device. It is widely used for input / output devices.

For example, a transparent electrode plate of a display device using liquid crystal has a glass substrate k as shown in FIG.
A color filter layer i that is provided in a pixel portion on the glass substrate k and colors the transmitted light of each pixel into red, green, and blue, and a portion between the pixels on the glass substrate k (inter-pixel portion). A light-shielding film m provided on the entire surface of the color filter layer i, and a transparent electrode g formed on the protective layer h. The alignment film 1 formed on the transparent electrode g constitutes the main part thereof. The transparent electrode g is formed of a transparent conductive film which is formed by sputtering and etched into a predetermined pattern.

An indium oxide thin film (IO thin film) is also known as a constituent material of this transparent conductive film.
An ITO thin film in which tin oxide is added as a dopant in the thin film to increase its conductivity is generally widely used.
The ITO thin film is formed by forming a vacuum film on the glass substrate k heated to a high temperature of 200 ° C. or higher by a sputtering method (substrate heating film forming method).
And a method of forming a film by vacuum annealing on a glass substrate k held at a low temperature of 150 ° C. or lower by sputtering and then annealing by heating (annealing method after low temperature film formation).

In order to further increase the conductivity of this transparent conductive film composed of an ITO thin film,
A transparent conductive film having a multi-layered structure formed by laminating metal thin films of gold, silver, copper or the like (Japanese Patent Publication No. 12663/1994 or JP-A-6-63).
1-25125) are also known.

Besides this, a tin oxide thin film, a thin film formed by adding antimony oxide to this tin oxide (nesa film), a thin film formed by adding aluminum oxide to zinc oxide, etc. are also known. However, all of them are inferior to the above-mentioned ITO thin film in general because they are inferior in electrical conductivity to the above-mentioned ITO thin film and have insufficient chemical resistance to water, acid or alkali.

[0007]

By the way, in the display device and the input / output device described above, it has been required in recent years to increase the pixel density to display a fine screen, and accordingly, the fineness of the transparent electrode pattern is required. It is required to form the terminal portions of the transparent electrodes at a pitch of, for example, about 100 μm. Further, in the method (COG) in which the liquid crystal driving IC is directly connected to the substrate in the liquid crystal display device, there is a portion where the wiring is a thin line with a width of 20 to 50 μm, and it has a high degree of suitability for etching, which is unprecedented. Conductivity (low resistivity) is required.

On the other hand, there is also a demand for a larger display screen. For such a large screen, a transparent electrode having a dense pattern as described above is formed so that a sufficient driving voltage can be applied to the liquid crystal. In order to do so, it is necessary to apply a transparent conductive film having high conductivity as the transparent electrode.

The conductivity of this transparent conductive film is generally expressed by area resistance (Ω / □) (area resistance is the reciprocal of area conductivity), and for example, a low area resistance of 5 Ω / □ or less is obtained. 3Ω / when required and for gradation display
□ A lower sheet resistance of less than □ is required.

The area conductivity of the transparent conductive film is
It is expressed as the product of conductivity (conductivity is expressed by the reciprocal of the above resistivity) and film thickness. This conductivity σ (Ω ^-1 cm ^-1 ) is the carrier (electron or positive) contained in the film. It is expressed by the product of the electric charge e (coulomb) of the hole), the mobility μ (cm ² / V · sec) of this carrier, and the carrier concentration n (cm ⁻³ ).

Σ (Ω ⁻¹ · cm ⁻¹ ) = e · μ · n (1) Therefore, according to the equation (1), the conductivity of the transparent conductive film is improved to lower its specific resistance and area resistance. To achieve this, the mobility μ (cm ² / V · sec) or carrier concentration n
It is sufficient to increase either one or both of (cm ⁻³ ).

In the ITO thin film generally used as the transparent conductive film, tin oxide is a dopant of indium oxide and this dopant is involved in the generation of electrons which are carriers as described above. It was predicted that when the amount of tin oxide was increased, the carrier concentration n (cm ⁻³ ) was increased, and accordingly, the electric conductivity and the area electric conductivity were increased, and the sheet resistance was decreased.

Therefore, the inventors of the present invention changed the added amount of tin oxide in the ITO thin film to change its specific resistance (Ω · c
m), carrier mobility μ (cm ² / V · sec), carrier concentration n (cm ⁻³ ), area resistance (Ω / □), etc., the amount of tin oxide increases contrary to the above prediction. As a result, the carrier mobility μ was decreased, and in the case of an ITO thin film having a practical thickness, a sheet resistance of about 5 to 10 Ω / □ was obtained at most.

On the other hand, in the transparent conductive film having the multilayer film structure described in Japanese Patent Publication No. 1-126363 or Japanese Patent Laid-Open No. 61-25125, in addition to the high conductivity of the ITO thin film, the conductivity of the metal thin film is high. Is expected to increase the conductivity of the entire transparent conductive film, and especially when a silver thin film is used as the metal thin film, the conductivity of the entire transparent conductive film is greatly increased due to the high conductivity of the silver thin film. Was expected to

On the other hand, however, since the silver thin film has a high light-shielding property, when a transparent conductive film is formed by using the silver thin film,
The film thickness is at most 20 nm, and if the film thickness is thicker than 20 nm, the transmittance of visible light decreases and the performance as a transparent conductive film cannot be ensured. Therefore, the film thickness 2
ITO on one or both sides of a silver thin film set to about 0 nm
The transparent conductive film obtained by laminating thin films has a maximum of 6
Only a sheet resistance of about 10 Ω / □ can be obtained, and sufficient conductivity cannot be secured even when the means described in Japanese Patent Publication No. 1-126363 or Japanese Patent Laid-Open No. 61-25125 is applied. There was a point.

Further, since the silver thin film is a soft metal, the silver thin film formed during the manufacturing process of a liquid crystal display or the like is easily scratched, and the adhesion to the ITO thin film is not good and the silver thin film is easily peeled off from the ITO thin film. There was a problem that lacked stability.

The present invention has been made by paying attention to such a problem, and an object thereof is to provide a transparent conductive film having high conductivity in a thin film and a method for forming the transparent conductive film. It is an object of the present invention to provide a transparent conductive film having a high cost and excellent processing stability, and a method for forming the transparent conductive film.

[0018]

In order to achieve this object, the present inventors have made the ITO disclosed in Japanese Patent Publication No. 1-12663 or JP-A No. 61-25125 based on the following technical inference. We tried to improve the transparent conductive film consisting of a thin film and a metal thin film such as silver.

That is, the ITO thin film constituting one of the transparent conductive films has good conductivity, but its carrier mobility is slightly low. Therefore, when a thin film having high carrier mobility is applied instead of the ITO thin film, a large amount of carriers generated from a thin metal film such as silver flows into the thin film having high carrier mobility and moves at high speed in this thin film. Therefore, it is expected to increase the conductivity of the entire transparent conductive film.

Based on such technical inference, the present inventors have replaced the ITO thin film with an IO thin film formed by an annealing method after low temperature film formation (the carrier mobility is high though the conductivity is inferior to the ITO thin film. ) Is applied and the thin film of silver or a silver alloy is laminated so as to be adjacent to each other to actually form a transparent conductive film, and the conductivity σ (Ω of the entire transparent conductive film obtained as predicted above is obtained. ⁻¹ · cm ⁻¹ ) is larger than any of the conductivity of each thin film, and the ITO thin film is applied to the above-mentioned Japanese Patent Publication No. 12663.
It was possible to realize higher conductivity than the transparent conductive film described in JP-A No. 61-25125. It was also confirmed that good results can be obtained even with the ITO thin film when the carrier mobility of this thin film is 60 cm ² / V · sec or more. The present invention has been completed based on such technical findings.

That is, the invention according to claim 1 has a carrier high-concentration thin film made of silver or a silver alloy and a carrier high-mobility thin film laminated adjacent to the carrier high-concentration thin film, and on a substrate. On the premise of the transparent conductive film formed on the substrate, the high carrier mobility thin film has a carrier mobility of 60 cm ² / V · sec or more, and the invention according to claim 2 is the invention according to claim 1. On the premise of the transparent conductive film according to the invention, the high-concentration carrier thin film contains silver as a main component and can form an intermetallic compound together with silver, and has excellent adhesion to the substrate and the high-mobility carrier thin film. It is characterized by containing a metal element.

In the transparent conductive film according to the first aspect of the present invention, the carrier high mobility thin film laminated adjacent to the carrier high concentration thin film made of silver or silver alloy is 60 cm ² / V · sec. Since it has the carrier mobility above and a large amount of carriers generated in the carrier high-concentration thin film migrates to the carrier high-mobility thin film and moves at high speed in the carrier high-mobility thin film, the transparent conductive film It is possible to increase the overall conductivity.

On the other hand, in the transparent conductive film according to the second aspect of the present invention, the carrier high concentration thin film contains silver as a main component,
It contains metal elements capable of forming intermetallic compounds with silver. Among these elements, silver comrades have strong cohesive force, and silver elements gather near the center of the carrier high concentration thin film, and the metal elements on both sides In order to eliminate them, the presence ratio of the above metal element is increased on the surface of the high-concentration carrier thin film, and an intermetallic compound composed of a silver-metal element is generated and firmly bonded to each other to be integrated. Since the intermetallic compound formed on the surface of the high-concentration carrier thin film is extremely hard because it has a regular structure due to its metal bond, it is necessary to prevent physical damage such as scratches after forming the transparent conductive film. Is possible.

Further, for the same reason, the metal element moved to the interface between the carrier high concentration thin film and its support (substrate or carrier high mobility thin film) has excellent adhesion to the substrate and carrier high mobility thin film. Adhesion of the carrier high-concentration thin film to the substrate and the carrier high mobility thin film is increased, and peeling of the transparent conductive film after forming the transparent conductive film can be prevented.

As described above, according to the second aspect of the present invention, the processing stability after formation of the transparent conductive film can be increased, so that the reliability of the manufactured liquid crystal display device or the like can be dramatically improved. It will be possible.

The metal element may be, for example, A
l, Be, Cd, Ce, Ga, La, Hf, In, M
Examples thereof include g, Na, Pt, Sb, Sn, Ti, Zn and Zr. It is also possible to use a second metal element that can form an intermetallic compound with silver and can form an intermetallic compound with the above metal element. Examples of the second metal element include Au, Bi, Ge, Mn, Pd, and Si. And among these, In, Mg or S
A more excellent effect is obtained when one or more metal elements selected from n are used. The inventions according to claims 3 and 4 relate to the invention in which the above metal element is specified.

That is, the invention according to claim 3 is premised on the transparent conductive film according to the invention according to claim 1 or 2, wherein the metal element is Al, Be, Cd, Ce, Ga, La, H.
f, In, Mg, Na, Pt, Sb, Sn, Ti, Z
n, Zr, Au, Bi, Ge, Mn, Pd or Si is composed of one or more elements, and the invention according to claim 4 is characterized in that the metal element is
It is characterized in that it is composed of one or more elements selected from In, Mg or Sn.

These metal elements can be added to the high carrier concentration thin film in an amount that does not reduce the carrier concentration. In addition, carrier impurities may be scattered due to these metal elements to lower the carrier mobility of the high-concentration carrier thin film, but the lower carrier mobility has little effect on the conductivity of the transparent conductive film. .

Next, as the carrier high mobility thin film according to the present invention, a transparent oxide thin film such as an indium oxide thin film or an indium oxide thin film to which a dopant such as tin oxide is added can be used. In order to secure a sufficient carrier mobility, it is preferable to add no dopant at all, or to add a very small amount of dopant, if any.

The invention according to claim 5 relates to the invention in which the material of the carrier high mobility thin film is specified.

That is, the invention according to claim 5 is premised on the transparent conductive film according to any one of claims 1 to 4, wherein the carrier high mobility thin film is a transparent oxide film based on indium oxide. It is characterized by being composed of objects.

In the invention according to any one of claims 1 to 5, the transparent conductive film can be constituted by a two-layer film composed of a single-layer high-concentration carrier thin film and a high-concentration carrier thin film. It is a three-layer film in which a single-layer carrier high-concentration thin film is interposed between the layer carrier high-mobility thin films,
It is also possible to further stack an ITO thin film on the above two-layer film to form a three-layer film. When a single-layer carrier high-concentration thin film is interposed between two layers of carrier high-mobility thin films, it is advantageous in that a transparent conductive film having high conductivity can be obtained. In the case of a three-layer film formed by stacking an ITO thin film to which tin oxide is added on the carrier high concentration thin film side of the two-layer film of the carrier high mobility thin film and the carrier high concentration thin film, the ITO thin film The carrier concentration of is higher than that of the indium oxide thin film (having a carrier concentration about 10 times that of the indium oxide thin film). It is possible to obtain a transparent conductive film having a small and stable conductivity.

The high carrier concentration thin film preferably has a thickness of 2 to 20 nm in order to secure the conductivity and transparency of the transparent conductive film, while the high carrier mobility thin film has a high carrier mobility. In order to ensure the above, it is desirable to have a thickness of about 20 nm to 300 nm, which is 2 to 3 times the mean free path of the carrier. Further, it is desirable that the crystal orientation planes at both thin film interfaces are the same so that carrier transfer between these high carrier concentration thin film and high carrier mobility thin film is favorably performed. When the orientation plane is the (222) plane, it is desirable that the orientation plane of the carrier high mobility thin film contacting the orientation plane is also the (222) plane.

It is also possible to protect the transparent conductive film by providing a transparent inorganic thin film on the transparent conductive film according to the present invention. The inorganic thin film may be provided on the entire surface of the transparent conductive film, but it is not necessary to expose the transparent conductive film, and it is desirable to selectively provide the inorganic thin film on a portion which is easily scratched in a processing step after the transparent conductive film is formed. For example, when the transparent conductive film is applied to the transparent electrode of the liquid crystal display device, an effective display portion excluding the terminal portion and the seal portion can be mentioned. Such inorganic thin films include SiO ₂ , ZrO ₂ , TiO ₂ , Ta ₂
Examples include O ₅ , HfO ₂ , CeO ₂ , and Al ₂ O ₃ .

Next, the invention according to claim 6 relates to a method of forming a transparent conductive film by an annealing method after low temperature film formation.

That is, the invention according to claim 6 is premised on a method of forming a transparent conductive film on a substrate, and a film for carrier high-concentration thin film and carrier high transfer are provided on a substrate kept at a temperature of 150 ° C. or lower. And a transparent oxide film for a thin film are sequentially formed, and these films are annealed by heating to form an intermetallic compound containing silver as a main component together with the silver. Carrier high concentration thin film containing metal element with excellent adhesion, 60 cm ² / V · se
It is characterized in that a transparent conductive film composed of a carrier high mobility thin film having a carrier mobility of c or more is formed.

In the invention according to claim 6, the film for carrier high-concentration thin film, the film for carrier high-mobility thin film, and the transparent oxide film are all known vacuum film formations such as vacuum deposition, ion plating, and sputtering. Although it is possible to form the film by the method, it is desirable to form any film by the sputtering method from the viewpoint of suppressing the variation in the film thickness and preventing the variation in the conductivity of the transparent conductive film. The invention according to claim 7 is made for such a technical reason.

That is, the invention according to claim 7 is premised on the method for forming a transparent conductive film according to the invention according to claim 6,
It is characterized in that both the above-mentioned film for carrier high-concentration thin film and the transparent oxide film for carrier high-mobility thin film are formed by a sputtering method.

Both of these coatings can be continuously formed without taking out the substrate housed inside the sputtering apparatus to the outside. Further, in the step of forming these both films, the substrate may be set to a temperature of around 150 ° C. to be in a dehydrated state, and the both films may be formed on the substrate in this dehydrated state. The film may be formed by keeping it at about room temperature without heating.

Next, the heat annealing according to claim 6 or 7 may be performed at a temperature of 180 ° C. or higher, and preferably 20.
The temperature is 0 to 300 ° C. Incidentally, since the etching suitability of the transparent conductive film may be lowered due to this annealing, it is desirable to etch the transparent conductive film into a required pattern before the annealing. For example, when a transparent conductive film is applied to a transparent electrode of a liquid crystal display, a method of etching the electrode pattern shape and then annealing by heating to increase its conductivity can be mentioned.
According to this method, since the thin film before annealing, which has excellent etching suitability, is etched, it is possible to form a transparent electrode having excellent pattern accuracy. The patterning can be performed by a well-known photolithography process.

Prior to the formation of the film for the carrier high concentration thin film or the transparent oxide film for the carrier high mobility thin film, the surface of the substrate is cleaned to increase the adhesion between the transparent conductive film and the substrate. It is possible to Examples of the cleaning method include ion bombardment, reverse sputtering, ashing, ultraviolet irradiation,
A method such as glow discharge treatment can be used.

Next, glass, ceramics, plastic films, plastic boards, etc. can be applied as the substrate for forming the transparent conductive film in the inventions according to claims 1 to 7, and they are colored in black, white or other colors. It may be one. It is also possible to use a substrate lined with a metal plate or a metal foil in order to improve heat dissipation and rigidity or to reflect visible light. Further, when the transparent conductive film according to the present invention is applied as a transparent electrode of a color display liquid crystal display, a substrate provided with a color filter layer for coloring transmitted light for each color, or an inorganic or organic layer on the color filter layer is provided. It is also possible to use a substrate provided with the above protective film. As such a color filter layer, a colored photoresist in which an organic pigment is dispersed in a photosensitive resin as a coloring material is used, and this is coated on a substrate to form a film, which is then patterned according to a photolithography process. A color filter layer provided as a color filter layer, a color filter layer provided by printing a transparent coloring ink, a color filter layer provided by electrodeposition of a coating material containing a transparent coloring pigment, or the like can be applied.

[0043]

According to the transparent conductive film of the present invention, the carrier high-concentration thin film made of silver or a silver alloy is laminated adjacent to the thin film, and the carrier mobility is 60 cm ² / Since it has a carrier high mobility thin film of V · sec or more, a large amount of carriers generated in the carrier high concentration thin film moves to the carrier high mobility thin film and moves at high speed in the carrier high mobility thin film. It is possible to increase the conductivity of the entire transparent conductive film.

Further, according to the transparent conductive film of the present invention, the high-concentration carrier thin film contains silver as a main component and can form an intermetallic compound together with silver. It contains a metal element with excellent adhesion to the mobility thin film, and among these elements, silver comrades have a strong cohesive force and the silver element gathers near the center of the carrier high concentration thin film to Since they are excluded on both sides, the presence ratio of the above metal element is increased on the surface of the carrier high concentration thin film, and an intermetallic compound composed of a silver-metal element is generated and firmly bonded to each other and integrated. The intermetallic compound generated on the surface of the carrier-concentrated thin film is extremely hard because it has a regular structure due to the metal bond, and therefore physical damage such as scratches after formation of the transparent conductive film can be prevented. It will be possible.

Further, since the metal element moved to the interface between the high carrier concentration thin film and the substrate or the carrier high mobility thin film has excellent adhesion to the substrate and the carrier high mobility thin film,
Adhesion of the carrier high-concentration thin film to the substrate and the carrier high mobility thin film is increased, and peeling of the transparent conductive film after forming the transparent conductive film can be prevented.

Further, according to the method for forming a transparent conductive film according to the sixth aspect of the present invention, a film for carrier high concentration thin film and a film for carrier high mobility thin film are formed on a substrate kept at a temperature of 150 ° C. or lower. A transparent oxide film is sequentially formed, and these films are annealed by heating to form an intermetallic compound containing silver as a main component together with this silver, and excellent adhesion to the substrate and carrier high mobility thin film. Since a transparent conductive film composed of a carrier high concentration thin film containing a metal element and a carrier high mobility thin film having a carrier mobility of 60 cm ² / V · sec or more is formed, the thin film has a high conductivity. It is possible to form a transparent conductive film that is high and has excellent processing stability.

Further, according to the invention of claim 7, both the film for the carrier high concentration thin film and the transparent oxide film for the carrier high mobility thin film are formed by the sputtering method. Variation can be suppressed, and variation in conductivity of the transparent conductive film can be prevented.

[0048]

EXAMPLES Examples of the present invention will be described in detail below.

Example 1 A transparent conductive film 1 according to this example is a glass substrate 1 having a thickness of 0.7 mm as shown in FIG.
No. 0, a stripe pattern having a width of 285 μm and a pitch of 300 μm. This transparent conductive film 1 has a carrier high mobility thin film (carrier mobility; about 100 cm ² / V · sec) 11 having a film thickness of 60 nm, which is sequentially laminated on the glass substrate 10 so as to be adjacent to each other, and a film thickness. High carrier concentration thin film 12 of 15 nm and film thickness of 60 nm
Carrier high mobility thin film (carrier mobility: about 100 cm
² / V · sec) 13 and a total film thickness of 135 nm.

The high-concentration carrier thin film 12 is made of silver 94.
The carrier high mobility thin films 11 and 13 are composed of a silver alloy thin film having a composition of atm%, Mg 3.5 atm%, and Sn 2.5 atm%, while the carrier high mobility thin films 11 and 13 are made of indium oxide thin film to which no dopant is added. It is configured.

The thin films 11, 12, and 13 are formed by the following steps.

That is, the glass substrate 10 washed with an alkaline surfactant and water was placed in a vacuum chamber and subjected to plasma treatment called reverse sputtering to clean the surface. Next, without heating the glass substrate 10 while keeping this vacuum (the temperature is kept at 150 ° C. or lower), the glass substrate 10 is sequentially coated on the glass substrate 10.
A thin film of indium oxide, a thin film of silver alloy, and a thin film of indium oxide were successively formed by a sputtering method. The silver alloy thin film is formed using a silver target in which Mg and Sn are embedded.

Next, the above-mentioned three-layer thin film was patterned into the above-mentioned stripe pattern according to a well-known photolithography process, and was further annealed under heating at 250 ° C. for 1 hour to form the transparent conductive film.

The sheet resistance of this transparent conductive film was measured to be 4.8 Ω / □, and it was confirmed that the sheet resistance was extremely low.

When the surface was rubbed with a Zemclip and the presence of scratches was visually inspected, no scratches could be observed and it was confirmed that the film was extremely hard.

Next, the following experiment was conducted in order to confirm the presence or absence of the intermetallic compound in the carrier high concentration thin film 12 and the relationship between the existence of the intermetallic compound and the hardness of the carrier high concentration thin film.

That is, as shown in FIG. 2, the thickness is 0.7 m.
A high-concentration carrier thin film 12x having a thickness of about 120 nm was formed on the glass substrate 10 having a thickness of m, and heat-annealed at 250 ° C. for 1 hour. The high carrier concentration thin film 12x has the same composition as the high carrier concentration thin film 12 according to the first embodiment, and the film forming method thereof is also the same.

Then, the above-mentioned carrier-high-concentration thin film 12x before heating and annealing was examined by X-ray diffraction. The X-ray diffraction chart is shown in FIG. Further, an X-ray diffraction chart after the heat annealing is shown in FIG. In FIG. 4, a shows the peak of the intermetallic compound AgMg, and b, c, d, and e show the peaks of the intermetallic compound Mg ₂ Sn, and these peaks are not seen in FIG. 3.

Next, using a diamond needle having a curvature R of the tip of 0.025 mm and a scratch strength tester (trade name: HEIDON) manufactured by Shinto Kagaku Co., Ltd., the above carrier before being heated and annealed. The high mobility thin film 12x was scratched and the scratch width t was measured as shown in FIG.
It was 06 μm. On the other hand, the scratch width of the carrier high mobility thin film 12x after the heat annealing was 41 μm. From these results, it was confirmed that the carrier high mobility thin film 12x containing the intermetallic compound was extremely hard. In addition, when a thin film of silver containing no Mg or Sn was formed and a scratch test was conducted in the same manner, the thin film was peeled off from the glass substrate 10 and the adhesion to the substrate was extremely poor. It was

[Embodiment 2] The transparent conductive film according to this embodiment is different in that the carrier high concentration thin film 12 has a composition of 93 atm% of silver, 1.5 atm% of indium and 5.5 atm% of tin. This is the same as in the first embodiment.

The sheet resistance of the transparent conductive film according to this example was 4.5 Ω / □. In addition, no scratch was observed even when the surface was rubbed with Zemclip.

[0062]

The invention according to claims 1 and 3 to 7 has the effect of increasing the conductivity of the transparent conductive film.

According to the invention of claims 2 to 7,
In addition to the increase in conductivity, physical damage and peeling after formation of the transparent conductive film can be prevented, so that the conductivity and processing stability of the transparent conductive film can be improved.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a transparent conductive film according to Example 1.

FIG. 2 is an explanatory view of an experimental method for measuring the hardness of a carrier high concentration thin film.

FIG. 3 is a graph showing an X-ray diffraction chart of a carrier high concentration thin film before heat annealing.

FIG. 4 is a graph showing an X-ray diffraction chart of a carrier high concentration thin film after heat annealing.

FIG. 5 is an explanatory view of an experimental method for measuring the hardness of a carrier high concentration thin film.

FIG. 6 is a cross-sectional view of a transparent electrode plate of a conventional liquid crystal display.

[Explanation of symbols]

 1 Transparent Conductive Film 11 Carrier High Mobility Thin Film 12 Carrier High Concentration Thin Film 13 Carrier High Mobility Thin Film

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location H01B 13/00 503 B

Claims (7)

[Claims] 1. A transparent conductive film having a carrier high-concentration thin film made of silver or a silver alloy and a carrier high-mobility thin film laminated adjacent to the carrier high-concentration thin film, and formed on a substrate. ^{2. The} transparent conductive film, wherein the high carrier mobility thin film has a carrier mobility of 60 cm ² / V · sec or more. 2. The high-concentration carrier thin film contains silver as a main component and a metal element capable of forming an intermetallic compound together with silver and having excellent adhesion to the substrate and the high-mobility carrier thin film. The transparent conductive film according to claim 1, wherein 3. The metal element is Al, Be, Cd, C
e, Ga, La, Hf, In, Mg, Na, Pt, S
b, Sn, Ti, Zn, Zr, Au, Bi, Ge, M
The transparent conductive film according to claim 1 or 2, which is composed of one or more elements selected from n, Pd, and Si. 4. The transparent conductive film according to claim 3, wherein the metal element is composed of one or more elements selected from In, Mg or Sn. 5. The transparent conductive film according to claim 1, wherein the carrier high mobility thin film is formed of a transparent oxide thin film having indium oxide as a base material. 6. A method for forming a transparent conductive film on a substrate, which comprises forming a film for carrier high concentration thin film and a transparent oxide film for carrier high mobility thin film on a substrate held at a temperature of 150 ° C. or lower. It contains a metal element which is formed in order, and these films are annealed by heating to form silver as a main component and an intermetallic compound with this silver, which has excellent adhesion to the above substrate and carrier high mobility thin film. Carrier high concentration thin film, 6
A method of forming a transparent conductive film, which comprises forming a transparent conductive film composed of a carrier high mobility thin film having a carrier mobility of 0 cm ² / V · sec or more. 7. The method for forming a transparent conductive film according to claim 6, wherein both the film for high-concentration carrier thin film and the transparent oxide film for high-mobility thin film carrier are formed by sputtering. .