WO2013115125A1

WO2013115125A1 - Method for manufacturing substrate having transparent electrode

Info

Publication number: WO2013115125A1
Application number: PCT/JP2013/051730
Authority: WO
Inventors: 貴久藤本; 拓明上田; 祐司 ▲高▼橋; 崇口山; 山本　憲治
Original assignee: 株式会社カネカ
Priority date: 2012-02-02
Filing date: 2013-01-28
Publication date: 2013-08-08
Also published as: TW201346937A

Abstract

The present invention pertains to a method for manufacturing a substrate having a transparent electrode layer comprising a metal oxide thin film provided on a transparent film. This manufacturing method has: a base material preparation step for introducing a roll-shaped wound body made from a transparent film into the base material preparation chamber of a winding-type sputtering film-forming device; a heating step in which the transparent film is subjected to a heating treatment in the base material preparation chamber, by heat from a heating unit, while being unrolled and transported from the roll-shaped wound body; and a transparent electrode layer film-forming step in which a transparent electrode layer made from an amorphous metal oxide thin film is formed on the heat-treated transparent film while an inert gas is introduced into the film-forming chamber of the winding-type sputtering film-forming device. The heating step and the transparent electrode layer film-forming step are performed continuously without the transparent film being removed from the sputtering film-forming device. In the heating step, heating is preferably performed without the transparent film and the heating unit coming into contact with each other. The pressure in the base material preparation chamber during the heating step is preferably no greater than 1.0 Pa.

Description

Manufacturing method of substrate with transparent electrode

The present invention relates to a method for producing a substrate with a transparent electrode comprising a transparent electrode layer on a transparent film.

A substrate with a transparent electrode in which a transparent electrode layer is formed on a transparent substrate such as a film or glass is used as a transparent electrode for a display such as a touch panel. As a method for producing such a substrate with a transparent electrode, a method of crystallizing a metal oxide by heating after forming an amorphous metal oxide thin film on a transparent substrate by sputtering or the like is known. (For example, Patent Document 1).

When a substrate with a transparent electrode is used for position detection of a capacitive touch panel, the transparent electrode layer is finely patterned. As the patterning method, for example, a method in which a transparent electrode layer is formed on substantially the entire surface of a transparent substrate and then the transparent electrode layer is removed by etching or the like in a part of the surface is used. As a result, a substrate with a transparent electrode having a transparent electrode layer patterned on an electrode forming portion (also referred to as “non-etching portion”) and an electrode non-forming portion (also referred to as “etching portion”) is obtained. . A transparent electrode used for position detection of a capacitive touch panel is required to have low resistance, high transparency, and good film quality.

As a method of forming a high-quality transparent electrode layer on a film, a method of heating a substrate film in advance before forming a transparent electrode layer by sputtering is known. For example, in Patent Document 2, a substrate film is heated in advance and thermally contracted, and a transparent electrode layer is formed on the film having a thermal contraction rate of 0.5% or less, thereby causing a change in resistance value or a film. It is disclosed that a substrate with a transparent electrode in which the occurrence of peeling is suppressed can be obtained. Further, Patent Document 3 discloses that the base film is wound in a winding type sputtering film forming apparatus, and the base film is heated with a film forming roll. By removing moisture in the film before forming the transparent electrode layer, the partial pressure of water in the film forming environment is reduced, and a low-resistance transparent electrode layer is obtained.

In the substrate with a transparent electrode on which the transparent electrode layer is patterned, in addition to the improvement of the film quality of the transparent electrode layer as described above, it is required that the pattern of the transparent electrode layer is difficult to be visually recognized. In patent document 3 and patent document 4, in order to suppress the visual recognition of the pattern of a transparent electrode layer, the transparent electrode layer is formed on the dielectric layer using a transparent film having a plurality of dielectric layers having different refractive indexes. A method for reducing the color difference between reflected light and transmitted light between the electrode forming portion and the electrode non-forming portion has been proposed.

International publication pamphlet of WO2010 / 035598 JP 2007-133839 A WO2010 / 140275 International Publication Pamphlet JP 2010-155861 A

According to the study by the present inventors, the above-mentioned optical design sufficiently suppresses the visual recognition of the pattern only by reducing the color difference between reflected light and transmitted light between the electrode forming portion and the electrode non-forming portion. I couldn't. This was thought to be due to the generation of wrinkles along the pattern boundary of the transparent conductive layer, and the reflection of light according to the shape of the wrinkles.

As a cause of generation of wrinkles along the pattern boundary of the transparent electrode layer, the present inventors first focused on a dimensional change due to heating of the base film. That is, as disclosed in Patent Document 2 above, when the metal oxide of the transparent electrode layer was crystallized by heating, it was estimated that the base film caused thermal contraction as a cause of wrinkles. However, even when the transparent electrode layer was formed using a base film (low thermal shrinkage film) whose thermal shrinkage rate was reduced in advance, wrinkles along the pattern boundary of the transparent electrode layer were not improved.

Next, the present inventors heated the film by rewinding in a winding-type sputtering film forming apparatus as disclosed in Patent Document 3, and simultaneously performed low thermal shrinkage and low moisture content. Thereafter, an attempt was made to form a transparent electrode layer. However, if the heating temperature at the time of rewinding is increased to about 80 ° C. in order to reduce the thermal shrinkage rate of the base film, the film transport state becomes unstable and winding deviation occurs, and the transparent electrode layer cannot be formed. The problem with.

As described above, in the substrate with a transparent electrode in which the transparent electrode layer is patterned, it is presumed that suppressing the generation of wrinkles along the pattern boundary of the transparent conductive layer is effective for suppressing pattern visual recognition. However, until now, no detailed examination has been made on the cause of wrinkles along the pattern boundary of the transparent electrode layer and a method for suppressing the same, and no effective means for suppressing pattern visual recognition has been found. In view of the above, an object of the present invention is to provide a substrate with a transparent electrode in which a pattern is difficult to be visually recognized by suppressing generation of wrinkles along a pattern boundary of a patterned transparent conductive layer.

As a result of intensive studies by the inventors, the film is heated in the film forming apparatus before the formation of the amorphous metal oxide thin film, whereby the pattern when crystallized and patterned after the transparent electrode layer is formed. The present inventors have found that generation of wrinkles along the boundary is suppressed, and have reached the present invention. That is, the present invention relates to a substrate with a transparent electrode provided with a transparent electrode layer made of an amorphous metal oxide thin film on a transparent film, and a method for producing the same.

In the present invention, it is preferable that a transparent electrode layer made of a metal oxide thin film is formed on a transparent film using a winding type sputtering film forming apparatus. As the transparent electrode layer, for example, a metal oxide thin film mainly composed of indium oxide such as ITO is formed.

The winding-type sputtering apparatus preferably includes a base material preparation chamber and a film forming chamber, and a heating unit is preferably provided in the base material preparation chamber. The production method of the present invention is a process in which a roll of a transparent film is introduced into a base material preparation chamber of a take-up type sputtering film forming apparatus (base material preparation step); A process of heating to a predetermined surface temperature by the heat from the heating unit while being fed out and conveyed from the roll-shaped winding body (heating process); and an inert gas in the film-forming chamber of the winding-type sputtering film-forming apparatus Is introduced, a transparent electrode layer made of an amorphous metal oxide thin film is formed on the transparent film after the heat treatment (transparent electrode layer forming step).

The transparent film introduced into the sputtering film forming apparatus preferably has a thermal shrinkage of 0.4% or less in at least one of the MD direction and the TD direction when heated at 150 ° C. for 30 minutes. In addition, the transparent film introduced into the sputtering film forming apparatus preferably has a thermal shrinkage start temperature measured by thermomechanical analysis (TMA) of 85 ° C. or higher.

It is preferable that the heating step and the transparent electrode layer film forming step are continuously performed without taking out the transparent film from the winding type sputtering film forming apparatus. In the heating step, it is preferable that the heat treatment is performed without contact between the transparent film and the heating portion. The pressure in the base material preparation chamber in the heating step is preferably 1.0 Pa or less.

After the heating step, it is preferable that the transparent electrode layer forming step is continuously performed in the film forming chamber before the transparent film after the heat treatment is wound into a roll. In the heating step, the heating time of the transparent film is preferably 0.1 second to 600 seconds. In the heating step, the temperature of the heating part is preferably 150 ° C. to 500 ° C.

In one embodiment, a plurality of heating units are provided in the substrate preparation chamber of the wind-up type sputtering film forming apparatus along the film conveyance direction, and heat treatment is performed by heat from the plurality of heating units. Is called. In the said form, it is preferable that the conveyance roll is arrange | positioned between several heating parts.

In the production method of the present invention, it is preferable that a transparent dielectric layer forming step is further provided between the heating step and the transparent electrode layer forming step. In the transparent dielectric layer forming step, at least one transparent dielectric layer is formed on the transparent film by a sputtering method. In the dielectric layer forming step, it is preferable that a dielectric layer composed of at least one silicon oxide layer is formed. The transparent dielectric layer formed immediately below the transparent electrode layer is preferably formed at a film forming pressure of 0.4 Pa or less.

In one embodiment, in the transparent dielectric layer forming step, a first transparent dielectric layer having a refractive index of 1.45 to 1.95, a second transparent dielectric layer having a refractive index of 2.00 to 2.35, And a third transparent dielectric layer made of silicon oxide is formed in this order on the transparent film.

In the production method of the present invention, the ratio P ₂₈ / P _I of the partial pressure P ₂₈ of the gas having a mass number 28 to the partial pressure P _I of the inert gas in the film forming chamber in the transparent electrode layer film forming step is 5 × 10 ^{− 4} or less is preferable.

The substrate with a transparent electrode obtained by the above production method preferably has a thermal shrinkage rate in the MD direction of 0.4% or less. The transparent electrode layer is preferably made of a metal oxide thin film mainly composed of amorphous indium oxide.

The substrate with a transparent electrode was heated by 150 ° C. for 30 minutes and obtained by out-plane X-ray diffraction measurement of the indium oxide crystal, by (222) plane spacing d _out and in-plane X-ray diffraction measurement. It is preferable that the ratio d _out / d _in of the surface interval d _in between the (222) planes to be obtained is 0.998 to 1.003.

The substrate with a transparent electrode obtained by the present invention suppresses generation of wrinkles along the pattern boundary of the transparent conductive layer when the transparent electrode layer is crystallized and patterned. Therefore, it is difficult to visually recognize the pattern boundary, and the visibility of the screen is improved when it is used for a capacitive touch panel.

It is a typical sectional view of a substrate with a transparent electrode concerning one embodiment. It is typical sectional drawing which shows the structural example of a winding-type sputtering film forming apparatus. It is typical sectional drawing which shows the structural example of the board | substrate with a transparent electrode by which the transparent electrode layer was patterned.

[Configuration of substrate with transparent electrode]
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a substrate 50 with a transparent electrode comprising a transparent electrode layer 30 made of a metal oxide thin film on a transparent film 10. Between the transparent film 10 and the transparent electrode layer 30, it is preferable that a transparent dielectric layer 20 mainly composed of an oxide is formed. When the transparent electrode layer 30 is directly formed on the transparent dielectric layer 20, the resistance of the transparent electrode layer is easily reduced.

The base film 11 constituting the transparent film 10 is preferably colorless and transparent at least in the visible light region. In one embodiment, the transparent film 10 has hard coat layers 12 and 13 on at least one surface of the base film 11.

The transparent dielectric layer 20 may be composed of only one layer or may be composed of two or more layers. FIG. 1 illustrates an example in which a first transparent dielectric layer 21, a second transparent dielectric layer 22, and a third transparent dielectric layer 23 are formed in this order from the transparent film 10 side. As the oxide constituting the transparent dielectric layer 20, an oxide that is colorless and transparent at least in the visible light region and has a resistivity of 10 Ω · cm or more is preferable. Note that in this specification, “having a main component” a substance means that the content of the substance is 51% by weight or more, preferably 70% by weight or more, and more preferably 90% by weight. As long as the function of the present invention is not impaired, each layer may contain components other than the main component.

The transparent electrode layer 30 is an amorphous metal oxide thin film. In this specification, “amorphous” may include a part (80% or less) of a crystalline part in a film. The content of the crystalline portion in the film can be determined from the ratio of the area occupied by the crystal grains in the observation field at the time of microscopic observation.

As the material constituting the transparent electrode layer 30, an oxide of at least one metal selected from the group consisting of indium, tin, zinc, gallium, aluminum, antimony, and titanium is preferably used. From the viewpoint of achieving both transparency and low resistance, the transparent electrode layer 30 is preferably composed mainly of indium oxide. The transparent electrode layer 30 preferably contains 88% to 98% by weight of indium oxide, more preferably 90% to 97% by weight, and even more preferably 94% to 96% by weight. . The transparent electrode layer preferably contains a doped impurity for imparting conductivity by providing a carrier density in the film. When the transparent electrode layer 30 is mainly composed of indium oxide, tin oxide or zinc oxide is preferable as the doping impurity, and tin oxide is particularly preferable.

The transparent electrode layer 30 is preferably one that is converted into a crystalline film when heated at 150 ° C. for 30 minutes. The crystalline film after heating preferably has a resistivity of 4.5 × 10 ⁻⁴ Ω · cm or less. Further, the crystalline film after heating preferably has a surface resistance of 150Ω / □ or less, and more preferably 140Ω / □ or less. If the transparent electrode layer has a low resistance, it can contribute to improvement of the response speed of the capacitive touch panel, power saving of various optical devices, and the like.

From the viewpoint of making the transparent electrode layer have low resistance and high transmittance, the thickness of the transparent electrode layer 30 is preferably 15 to 40 nm, more preferably 21 nm to 38 nm, and further preferably 23 nm to 35 nm.

When such a substrate with a transparent electrode is used for position detection of a capacitive touch panel, as shown in FIG. 3, a part of the surface of the transparent electrode layer 30 is etched with the electrode forming portion 30a. Patterning is performed on the electrode non-forming portion 30b. In this case, by adjusting the thickness and refractive index of the transparent dielectric layer 20, the electrode forming portion 30a where the transparent electrode layer remains without being etched, and the electrode non-forming portion 30b where the electrode layer is removed by etching. The transmittance difference, the reflectance difference, and the color difference can be reduced, and the visual recognition of the electrode pattern can be suppressed.

[Method for producing substrate with transparent electrode]
Hereinafter, a preferred embodiment of the present invention will be described along a manufacturing method of a substrate with a transparent electrode. In the manufacturing method of this invention, the transparent electrode layer which consists of a metal oxide thin film is formed on a transparent film using a winding type sputtering film forming apparatus. Winding-type sputtering can form a transparent electrode layer on a transparent film with high productivity by a roll-to-roll method. In film formation by winding-type sputtering, the wound body of the transparent film 10 is introduced into the winding-type sputtering film-forming apparatus (base material preparation process) and heated in the winding-type sputtering film-forming apparatus (heating process). Thereafter, the transparent electrode layer 30 made of an amorphous metal oxide thin film is formed on the transparent film 10 (film forming step). In this invention, it is preferable that a heating process and a transparent electrode layer film forming process are performed continuously, without taking out a transparent film out of a sputtering film forming apparatus.

(Configuration example of film forming device)
FIG. 2 is a schematic cross-sectional view showing an example of a winding type sputtering film forming apparatus used in the present invention. The sputtering film forming apparatus 200 is partitioned into a base material preparation chamber 201 and

film forming chambers

202 and 203, and a film forming roll 260 is provided adjacent to the partitions of these chambers. A feeding roll 261 and a take-up roll 262 are provided in the base material preparation chamber 201. Further, conveyance rolls 263 to 268 are arranged between the feeding roll 261 and the film forming roll 260 and between the film forming roll 260 and the take-up roll 262 in the base material preparation chamber 201. Furthermore,

heaters

271 and 272 are provided as heating units in the vicinity of the film conveyance path between the feeding roll 261 and the film forming roll 260 in the base material preparation chamber 201.

In the winding type sputtering apparatus 200, the wound body of the transparent film 10 is set on the feeding roll 261. The transparent electrode layer 30 is formed on the film forming roll 260 while the transparent film 10 is continuously conveyed from the base material preparation chamber 201 to the

film forming chambers

202 and 203. The substrate 50 with a transparent electrode after film formation is transported again to the base material preparation chamber 201 and wound up by a winding roll 262 to obtain a roll-shaped wound body 250 of the substrate with a transparent electrode.

Cathodes

282 and 283 are disposed near the film forming rolls 260 in the

film forming chambers

202 and 203, and targets 222 and 223 are disposed between the cathodes and the film forming rolls.

(Base material preparation process)
The base film 11 constituting the transparent film 10 is not particularly limited as long as it is colorless and transparent at least in the visible light region and has heat resistance at the heating temperature in the heating step described later. Examples of the transparent film material include polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene naphthalate (PEN), cycloolefin resins, polycarbonate resins, polyimide resins, and cellulose resins. Can be mentioned. Of these, polyester resins are preferable, and polyethylene terephthalate is particularly preferably used.

The thickness of the base film 11 is not particularly limited, but is preferably 10 μm to 400 μm, more preferably 50 μm to 300 μm. If the thickness is within the above range, the base film 11 can have durability and moderate flexibility, so that the transparent dielectric layer and the transparent electrode layer are formed thereon with high productivity by a roll-to-roll method. It is possible to form a film.

As the base film 11, a film in which mechanical properties such as Young's modulus and heat resistance are improved by orienting molecules by biaxial stretching is preferably used. The base film 11 can also be used for film formation as the transparent film 10 as it is. From the viewpoint of imparting appropriate durability to the transparent film 10, the transparent film 10 in which the hard coat layers 12 and 13 are formed on one side or both sides of the base film 11 is preferably used.

In order to give the transparent film 10 appropriate durability and flexibility, the thickness of the hard coat layer is preferably 3 to 10 μm, more preferably 3 to 8 μm, and even more preferably 5 to 8 μm. The material of the hard coat layer is not particularly limited, and a material obtained by applying and curing a urethane resin, an acrylic resin, a silicone resin, or the like can be appropriately used.

Various functional layers other than the hard coat layer may be formed on the base film 11. For example, the transparent dielectric layer 20 may be formed as a functional layer directly on the base film 11 or on the hard coat layer 12. As the oxide constituting the transparent dielectric layer, an oxide of one or more elements selected from the group consisting of Si, Nb, Ta, Ti, Zn, Zr and Hf is preferably used. The method for forming the transparent dielectric layer is not particularly limited as long as a uniform thin film is formed. Examples of the film forming method include PVD methods such as sputtering and vapor deposition, dry coating methods such as various CVD methods, and wet coating methods such as spin coating, roll coating, spray coating, and dipping coating. Among the above film forming methods, the dry coating method is preferable from the viewpoint of easily forming a nanometer-level thin film.

When the transparent dielectric layer is formed by sputtering, the transparent dielectric is formed after the base material preparation step in which the transparent film 10 is introduced into the winding type sputtering film forming apparatus 200 and before the transparent electrode layer 30 is formed. Layer 20 may be formed. Further, when two or more transparent dielectric layers are formed, one or more transparent dielectric layers are formed before the transparent film is introduced into the sputtering film forming apparatus, and the transparent film is formed in the sputtering film forming apparatus. After the introduction of, one or more transparent dielectric layers may be formed before the transparent electrode layer is formed. For example, after the first transparent dielectric layer 21 is formed on the transparent film 10 by the wet coating method, the transparent film 10 after the formation of the first transparent dielectric layer 21 is introduced into the sputtering apparatus, and the second transparent dielectric layer 21 is formed by the sputtering method. The transparent dielectric layer 22, the third transparent dielectric layer 23, and the transparent electrode layer 30 may be formed continuously. From the viewpoint of controlling the film thickness of the transparent dielectric layer and enhancing the productivity of the film with a transparent electrode, it is preferable that all the transparent dielectric layers are formed by sputtering. In addition, about embodiment (transparent electrode layer film forming process) in which a transparent dielectric material layer is formed in the same winding type sputtering film forming apparatus after forming the transparent electrode layer after the base material preparing process, Detailed description.

The transparent film 10 introduced into the sputtering film forming apparatus preferably has a thermal shrinkage rate of 0.4% or less, more preferably 0.35% or less when heated at 150 ° C. for 30 minutes. More preferably, it is 3% or less. When the heat shrinkage rate varies depending on the direction (when it differs between the MD direction and the TD direction), the heat shrinkage rate in the MD direction may be in the above range. In particular, it is preferable that the thermal shrinkage rate in both the MD direction and the TD direction is in the above range. Hereinafter, unless otherwise specified, the “heat shrinkage rate” in this specification represents the shrinkage rate when heated at 150 ° C. for 30 minutes. The thermal contraction rate is calculated by the following formula from the distance between two points before heating (L ₀ ) and the distance between two points after heating (L).
Formula: Thermal contraction rate (%) = 100 × (L ₀ −L) / L ₀

The transparent film 10 introduced into the sputtering film forming apparatus preferably has a thermal shrinkage start temperature measured by thermomechanical analysis of 85 ° C. or higher, more preferably 90 ° C. or higher, and further 100 ° C. or higher. preferable. Ideally, the transparent film 10 does not exhibit a heat shrinkage starting temperature in the range up to 200 ° C. The thermal shrinkage start temperature is obtained from the maximum value of the displacement amount when the temperature is increased at a predetermined load and the rate of temperature increase by thermal instrument analysis (TMA).

(Heating process)
The transparent film 10 introduced into the sputtering film forming apparatus 200 is heat-treated in the base material preparation chamber 201 before the transparent electrode layer 30 is formed. Before the heat treatment is performed, the pressure in the base material preparation chamber 201 is preferably once reduced to 0.01 Pa or less. The pressure in the base material preparation chamber 201 during the heat treatment is preferably 1.5 Pa or less, more preferably 1.0 Pa or less, and further preferably 0.5 Pa or less.

The transparent film 10 is heated by heat from the

heating units

271 and 272 in the base material preparation chamber. The heating temperature is preferably set so that the surface temperature of the transparent film is 70 ° C. to 160 ° C. The surface temperature of the film in the heating step is more preferably 80 ° C. to 160 ° C., further preferably 85 ° C. to 120 ° C. The surface temperature of the film can be measured by attaching a thermolabel or a thermocouple to the film surface.

The heating unit is preferably a device that does not come into contact with the film, such as a temperature control mechanism such as a heater or a heat pipe using a microwave or far infrared rays, a hot air blowing nozzle, or the like. In a heating process, when a heating part and a film do not contact, it can suppress that the generation | occurrence | production of the wrinkles resulting from the rapid thermal deformation of a film, etc. and the conveyance of a film become unstable. When the heating unit is arranged so as not to contact the film, the distance between the heating unit and the film transport path is preferably about 5 mm to 100 mm, and more preferably about 10 mm to 70 mm.

The heating of the transparent film may be performed from one side of the transparent film or from both sides. From the viewpoint of effective heating, it is preferable that

heaters

271 and 272 are provided in the vicinity of both surfaces of the transparent film conveyance path, and heating is performed from both surfaces, as shown in FIG. When heating is performed while the transparent film 10 is transported in the winding-type sputter film forming apparatus 200, the heating time can be adjusted by the shape of the heater (length in the film transport direction) and the film transport speed. .

In order to secure the heating time, heating units may be provided at two or more locations in the film conveyance direction. As a form in which a plurality of heating units are provided along the film conveyance direction, for example, in FIG. 2, in addition to the

heaters

271 and 272, a heater is provided between the conveyance roll 264 and the conveyance roll 265 in the base material preparation chamber 201. An example in which 273 and 274 are arranged is given.

By providing a plurality of heating units along the film transport direction, a predetermined heating time is ensured without lowering the film transport speed, and heat treatment is performed so that the surface temperature of the film falls within the above range. Can do. Therefore, the heat treatment process is made efficient and the productivity of the substrate with a transparent electrode can be increased. In addition, by providing a transport roll between the plurality of heating units, it is possible to effectively use the space in the film forming preparation chamber 201 to secure the heating time, stabilize the transport of the film, And the occurrence of slack can be suppressed.

The heating time in the heat treatment is preferably from 0.1 seconds to 600 seconds, more preferably from 0.5 seconds to 300 seconds, and further preferably from 1 second to 180 seconds. The temperature of the heating unit (heaters 271 and 272) can be appropriately determined according to the heating time, the interval between the heating unit and the film conveyance path, and the like so that the surface temperature of the film falls within the above range. The heating temperature is, for example, preferably 150 ° C. to 500 ° C., more preferably 180 ° C. to 400 ° C., and further preferably 200 ° C. to 350 ° C.

When the transparent film is heat-treated before the transparent electrode layer is formed, generation of wrinkles along the pattern boundary is suppressed when crystallization and patterning are performed after the transparent electrode layer is formed. According to the study by the present inventors, after the amorphous transparent electrode layer is formed by sputtering, the film with a transparent electrode having a large amount of curling when the transparent electrode layer is crystallized by heating is: After that, when the transparent electrode layer was patterned, there was a tendency that wrinkles at the pattern boundary were easily visible. The occurrence of curling at the time of heat crystallization is presumed to be due to stress generated at the interface between the transparent electrode layer and the transparent film when the substrate with the transparent electrode is heated. In the present invention, when the transparent film is heated before forming the transparent electrode layer, a change occurs in the state of the film forming interface of the transparent electrode layer, which is considered to contribute to suppression of wrinkles. As the change in the state of the film forming interface, for example, it is presumed that the volatilization of organic components adsorbed on the transparent film or on the film surface contributes to the heat treatment.

(Film forming process)
The heated transparent film 10 is conveyed to the

film forming chambers

202 and 203, and the transparent electrode layer 30 is formed in the film forming chambers. The formation of the transparent electrode layer is preferably performed continuously without removing the heated transparent film 10 from the sputtering film forming apparatus 200. By forming the transparent electrode layer without removing the heated transparent film from the film forming apparatus, adsorption of moisture, organic components, etc. in the atmosphere to the film surface is suppressed. Moreover, productivity of a board | substrate with a transparent electrode is improved by heating and film forming of a film continuously.

When film formation is performed using a winding-type sputtering film forming apparatus, after the heating step, the transparent film is once wound around the roll-shaped winding body by the winding roll 262, and then again from the winding body to the transparent film. May be fed and film formation may be performed while the film is conveyed. In this invention, it is preferable that a transparent electrode layer film forming process is continued before the transparent film after a heating is wound by roll shape. That is, in the present invention, the transparent film 10 drawn out from the roll-shaped wound body 210 is heated to a predetermined temperature by the heat from the

heating units

271 and 272 in the base material preparation chamber 201, and then the film forming chamber 202. , 203, the transparent electrode layer 30 is preferably formed on the film forming roll 260. From the viewpoint of improving production efficiency, the time interval from the heating step to the film forming step is preferably within 10 minutes, more preferably within 8 minutes, and even more preferably within 5 minutes. The time interval from the heating step to the film forming step can be set to the above range by continuously performing the film forming step after the heating step without rewinding the transparent film in the sputtering film forming apparatus.

The transparent electrode layer 30 is formed while a carrier gas containing an inert gas such as argon and an oxygen gas is introduced into the

film forming chambers

202 and 203. The introduced gas is preferably a mixed gas of argon and oxygen. The mixed gas preferably contains 0.4% to 2.0% by volume of oxygen, more preferably 0.7% to 1.5% by volume. By supplying the volume of oxygen, the transparency and conductivity of the transparent electrode layer can be improved. The mixed gas may contain other gases as long as the function of the present invention is not impaired. The pressure (total pressure) in the film forming chamber is preferably 1.5 Pa or less, more preferably 0.05 Pa to 1.2 Pa, and further preferably 0.1 Pa to 0.9 Pa.

In the transparent electrode layer deposition step, the ratio P ₂₈ / P _I of the partial pressure P ₂₈ of the gas having a mass number 28 to the partial pressure P _I of the inert gas in the deposition chamber is less than 5 × 10 ^−4. Is preferred. P ₂₈ / P _I is more preferably 1.0 × 10 ⁻⁵ to 5 × 10 ⁻⁴ , and further preferably 5.0 × 10 ⁻⁵ to 5 × 10 ⁻⁴ . By reducing the gas partial pressure of mass number 28 in the film-forming atmosphere, the state of the transparent electrode layer formation interface changes, so the stress at the interface between the transparent electrode layer and the film decreases, The generation of wrinkles when the transparent electrode layer is patterned is suppressed. The gas partial pressure of mass number 28 can be monitored by an on-line quadrupole mass spectrometer (Q-mass).

The gas having a mass number of 28 in the film forming chamber is considered to be mainly carbon monoxide and nitrogen. The carbon monoxide gas is considered to be released into the film forming atmosphere due to plasma damage or the like when the transparent electrode layer is formed on the transparent film by sputtering. Further, the nitrogen gas is considered to have been released into the film forming atmosphere from the hard coat layers 12 and 13 formed on the surface of the base film 11.

In the present invention, by providing a heating step in the base material preparation chamber 201 before forming the transparent electrode layer, the partial pressure of the gas having a mass number of 28 in the

film forming chambers

202 and 203 can be within the above range. it can. That is, when the transparent film is heated at a relatively high temperature for a short time, organic substances that cause carbon monoxide and nitrogen to be generated from the inside of the transparent film or the surface of the transparent film are volatilized before forming the transparent electrode layer. It is considered that generation of a gas having a mass number of 28 due to plasma damage or the like during film formation is suppressed.

Conventionally, the transparent film has been heated under vacuum before forming the transparent electrode layer in order to reduce the water content in the transparent film and promote the crystallization of the metal oxide. In order to reduce the amount of water in this way, heating at a low temperature for a long time is necessary. After the transparent film 10 is unwound from the roll-shaped wound body 210, until the transparent electrode layer 30 is formed on the film-forming roll 260, the moisture content is reduced in the conveyance path in the base material preparation chamber 201. It is difficult to perform sufficient heat treatment. On the other hand, the heating process in the present invention is a treatment at a high temperature for a short time. Therefore, after the transparent film 10 is drawn out from the roll-shaped wound body 210 and before the transparent electrode layer 30 is formed on the film-forming roll 260, heat treatment is performed in the base material preparation chamber 201. Can do. That is, since the heat treatment is a short time step, the transparent electrode layer can be formed following the heating step without the transparent film being once wound into a roll after the heating step. In addition, since the transparent film 10 is heated in a non-contact manner with the

heating units

271 and 272, even if the heating is performed at a high temperature, the film conveyance state becomes unstable as in the case where the heating is performed on the film forming roll. Problems such as winding misalignment of the wound body are unlikely to occur.

A DC, RF, MF power source or the like can be used as a sputtering power source when forming the transparent electrode layer. As a material of the

targets

222 and 223 used for sputtering film formation, metals such as indium, tin, zinc, gallium, aluminum, antimony, and titanium, or oxides of these metals are used. In the case where a metal oxide film mainly composed of indium such as indium tin oxide (ITO) or indium oxide zinc (IZO) is formed as the transparent electrode layer 30, the target is 88% by weight of indium oxide. It is preferably contained in an amount of ˜98% by weight, more preferably 90% by weight to 97% by weight, and even more preferably 94% by weight to 96% by weight.

The substrate temperature at the time of forming the transparent electrode layer may be in the range where the transparent film has heat resistance. The substrate temperature is preferably −40 ° C. to 40 ° C., more preferably −30 ° C. to 30 ° C., further preferably −20 ° C. to 20 ° C., and −10 ° C. to 10 ° C. It is particularly preferred. By setting the substrate temperature to 40 ° C. or lower, generation of a gas having a mass number of 28 due to plasma damage or the like is suppressed. Further, by setting the substrate temperature to −40 ° C. or higher, it is possible to suppress a decrease in the transmittance of the transparent electrode layer and embrittlement of the transparent film.

(Dielectric layer deposition process)
In one embodiment of the present invention, after the transparent film 10 is heated by the heat from the

heating units

271 and 272 in the base material preparation chamber 201, the transparent electrode layer 30 is manufactured on the film forming roll 260 in the film forming chamber. It is preferable that the transparent dielectric layer 20 be formed before being formed.

For example, after the transparent film is heated, the transparent dielectric layer 20 is formed on the film forming roll 260, and after the transparent film 10 after forming the transparent dielectric layer 20 is once wound on the wound body 250, again. A film is drawn out from the wound body 250 and the transparent electrode layer 30 is formed. In this case, the heat treatment may be performed once again after the film is unwound from the wound body 250 and the transparent electrode layer 30 is formed.

In the present invention, it is preferable that the transparent dielectric layer 20 and the transparent electrode layer 30 are continuously formed on the film forming roll 260 after heating the transparent film. For example, in FIG. 2, an oxide target made of a material constituting a dielectric layer is used as the target 222 in the film forming chamber 202, and a target constituting the transparent electrode layer is made as the target 223 in the film forming chamber 203. By using a metal oxide target, the transparent dielectric layer 20 and the transparent electrode layer 30 are continuously formed. In FIG. 2, a configuration having the

cathodes

282 and 283 in the two

film forming chambers

202 and 203 is shown, but the sputtering film forming apparatus may include three or more film forming chambers. . By providing a cathode and a target in each of the three or more film forming chambers, two or more dielectric layers and transparent electrode layers (three or more layers in total) can be continuously formed.

The transparent dielectric layer 20 includes a gas barrier layer that suppresses the evaporation of moisture and organic substances from the transparent film 10 when the transparent electrode layer 30 is formed thereon, and a protective layer that reduces plasma damage to the transparent film. As well as an underlayer for film growth. In particular, in the present invention, since the dielectric layer can act as a gas barrier layer, it is expected that generation of a gas having a mass number of 28 during the formation of the transparent electrode layer is suppressed. From the viewpoint of imparting these functions to the transparent dielectric layer 20, the thickness of the transparent dielectric layer 20 is preferably 10 nm to 100 nm, more preferably 15 nm to 85 nm, and 20 nm to 80 nm. Is more preferable.

As the oxide constituting the transparent dielectric layer 20, an oxide of one or more elements selected from the group consisting of Si, Nb, Ta, Ti, Zn, Zr and Hf is preferably used. Among these, silicon oxide (SiO ₂ ) is preferable. In the manufacturing method of the present invention, the transparent electrode layer 30 is formed on the transparent dielectric layer mainly composed of silicon oxide, so that wrinkles along the pattern boundary occur when the transparent electrode layer is patterned. Tend to be difficult.

When the transparent dielectric layer 20 consists of two or more layers, by adjusting the thickness and refractive index of each layer, the transmittance and reflectance of the substrate with a transparent electrode can be adjusted, and the visibility of the display device can be improved. . As shown in FIG. 3, when a part of the surface of the transparent electrode layer 30 is patterned by etching or the like, the electrode forming portion 30a and the electrode are adjusted by adjusting the thickness and refractive index of the transparent dielectric layer. The transmittance difference, reflectance difference, and color difference from the non-forming portion 30b can be reduced to prevent the electrode pattern from being visually recognized.

The arithmetic average roughness Ra of the surface of the transparent dielectric layer 20 is preferably 1 nm or less, more preferably 0.8 nm or less, and further preferably 0.6 nm or less. The arithmetic average roughness Ra is calculated in accordance with JIS B0601: 2001 (ISO1302: 2002) based on the surface shape (roughness curve) measured by a non-contact method using a scanning probe microscope. By smoothing the interface on which the transparent electrode layer 30 is formed, the resistance of the transparent electrode layer 30 formed thereon is reduced, and when the transparent electrode layer is patterned, the wrinkles along the pattern boundary are reduced. It tends to be suppressed.

When a silicon oxide layer is formed as the transparent dielectric layer, the arithmetic average roughness Ra of the surface tends to be reduced by reducing the film forming pressure (total pressure in the film forming chamber). The film forming pressure of the dielectric layer is preferably 0.4 Pa or less, more preferably 0.35 Pa or less, and further preferably 0.25 Pa or less. When a plurality of transparent dielectric layers are formed, in order to reduce the arithmetic average roughness of the surface of the transparent dielectric layer 20, the dielectric layer 23 in contact with the transparent electrode layer 30 is formed at the film forming pressure. It is preferable. Although the reason why the pattern wrinkles of the transparent electrode layer is suppressed by adjusting the film forming conditions of the dielectric layer 23 in contact with the transparent electrode layer 30 is not clear, the crystallinity and surface shape of the dielectric layer as the underlayer, One possible reason is that the surface properties affect the film growth of the transparent electrode layer.

Further, when two or more silicon oxide layers are formed as the transparent dielectric layer, they are not in contact with the transparent electrode layer 30 from the viewpoint of suppressing the generation of wrinkles when the transparent electrode layer is patterned. The dielectric layer is also preferably formed under a pressure of 0.4 Pa or less. The film forming pressure of the dielectric layer is more preferably 0.35 Pa or less, and further preferably 0.25 Pa or less. The reason why the pattern wrinkles of the transparent electrode layer is suppressed by adjusting the film forming conditions of the dielectric layer not in contact with the transparent electrode layer 30 is not clear, but the crystallinity, surface shape, and surface properties of the dielectric layer And the like influence the film growth of the dielectric layer 23 in contact with the transparent electrode layer 30 and the transparent electrode layer.

As an example of the configuration of the transparent dielectric layer 20 for suppressing the visual recognition of the electrode pattern by the optical design, the refractive index n ₁ is 1.45 to 1.95 and the film thickness is 1 nm to 25 nm from the transparent film 10 side. The first transparent dielectric layer 21, the second transparent dielectric layer 22 having a refractive index n ₂ of 2.00 to 2.35 and a film thickness of 5 nm to 10 nm, and the refractive index n ₃ of 1.43 to 1.55. And the third transparent dielectric layer 23 having a film thickness of 35 nm to 80 nm. The refractive index n ₁ of the first dielectric _layer, the refractive index n ₃ of the second refractive index n ₂ of the dielectric _layer, and a third dielectric layer satisfy the relationship of n 3 _<n 1 _<n ₂ Is preferred. Since the refractive index of each dielectric layer has such a magnitude relationship, the reflectance at the interface of the dielectric layer is appropriately controlled, and a substrate with a transparent electrode having excellent visibility can be obtained. In addition, the refractive index of each dielectric material layer and transparent electrode layer is a refractive index with respect to the light of wavelength 550nm measured by spectroscopic ellipsometry. The film thickness of each layer is determined by a transmission electron microscope (TEM).

In the configuration thus transparent dielectric layer 20 is composed of three layers, the material of the first transparent dielectric layer _21, a silicon oxide layer mainly composed of SiO x (1.5 ≦ x <2 ) is preferable . The film thickness d ₁ of the first transparent dielectric layer 21 is preferably 1 nm to 25 nm, more preferably 2 nm to 22 nm, still more preferably 3 to 20 nm, and particularly preferably 4 nm to 15 nm. The refractive index of the first dielectric layer is preferably 1.45 to 1.95, more preferably 1.47 to 1.85, and still more preferably 1.49 to 1.75.

The material of the second transparent dielectric layer 22 is mainly composed of an oxide of a metal selected from the group consisting of Nb, Ta, Ti, Zr, Zn, and Hf, or a composite oxide of these metals. Is preferred. The film thickness of the second transparent dielectric layer 22 is preferably 4 nm to 12 nm, and more preferably 6 nm to 10 nm. The refractive index of the second dielectric layer is preferably 2.00 to 2.35, more preferably 2.05 to 2.30, and even more preferably 2.10 to 2.25.

The second transparent dielectric layer 22 preferably has a small absorption in the short wavelength region of visible light. From such a viewpoint, the material of the second transparent dielectric layer 22 is preferably niobium oxide (Nb ₂ O ₅ ), tantalum oxide (Ta ₂ O ₅ ), titanium oxide (TiO ₂ ), or zirconium oxide (ZrO ₂ ). Of these, niobium oxide is preferably used.

The material of the third transparent dielectric layer 23, a silicon oxide layer mainly composed of SiO ₂ is preferred. The film thickness of the third transparent dielectric layer 23 is preferably 30 nm to 80 nm, more preferably 35 nm to 70 nm, and even more preferably 40 to 70 nm. From the viewpoint of optimizing the optical design, the thickness of the third dielectric layer is preferably in the range of 30 nm to 55 nm. On the other hand, when the film thickness of the third dielectric layer is 55 nm or more, wrinkles tend to be further reduced. The refractive index n ₃ of the third transparent dielectric layer 23 is preferably 1.43 to 1.58, more preferably 1.45 to 1.55, and even more preferably 1.47 to 1.53.

As described above, the third dielectric layer 23 which is a dielectric layer in contact with the transparent electrode layer 30 preferably has an arithmetic average roughness Ra of the transparent electrode layer forming side interface of 1 nm or less, and 0.8 nm or less. It is more preferable that the thickness is 0.6 nm or less. The film forming pressure of the third dielectric layer is preferably 0.4 Pa or less, more preferably 0.35 Pa or less, and further preferably 0.25 Pa or less.

When each dielectric layer has the above thickness and refractive index, the electrode pattern of the transparent electrode layer 30 formed thereon tends to be difficult to be visually recognized. In order to more effectively suppress the visibility of the pattern of the transparent electrode layer, the optical film thickness of the first transparent dielectric layer 21 is preferably 2 nm to 40 nm, more preferably 4 nm to 36 nm, More preferably, it is 6 nm to 32 nm. The optical film thickness of the second transparent dielectric layer is preferably 4 nm to 20 nm, more preferably 5 nm to 15 nm, and further preferably 6 nm to 12 nm. The optical film thickness of the third transparent dielectric layer is preferably 30 nm to 110 nm, more preferably 40 nm to 90 nm, and further preferably 45 nm to 80 nm. From the viewpoint of optimizing the optical design, the optical film thickness of the third dielectric layer is more preferably 80 nm or less, and further preferably 70 nm or less. On the other hand, from the viewpoint of further suppressing the generation of wrinkles, the optical film thickness of the third dielectric layer is more preferably 55 nm or more, and further preferably 60 nm or more. The optical film thickness is represented by the product of the film thickness and refractive index of each layer.

When the transparent dielectric layer 20 has the above-described three-layer configuration, as shown in FIG. 3, the light reflectance difference and color difference between the electrode forming portion 30 a and the electrode non-forming portion 30 b when the transparent electrode layer 30 is patterned. Can be reduced, and visual recognition of the pattern can be suppressed by the optical design. Furthermore, in the present invention, by forming the transparent electrode layer 30 on the transparent dielectric layer 23 made of silicon oxide, the generation of pattern defects when the transparent electrode layer is patterned is also suppressed. There is a tendency that the visual recognition of the pattern is suppressed.

When each dielectric layer is formed by sputtering, a metal, metal oxide, metal carbide, or the like can be used as a target. As the power source, a DC, RF, MF power source or the like can be used, but an MF power source is preferable from the viewpoint of productivity. The applied power at the time of film formation is not particularly limited, but is preferably adjusted within a range that does not give excessive heat to the transparent film substrate and does not impair productivity. For example, when the transparent dielectric layer 20 has the above-described three-layer structure, the power density at the time of forming the first dielectric layer is preferably 0.5 to 10 W / cm ^{2, and} the power density at the time of forming the second dielectric layer is The density is preferably 0.5 to 8 W / cm ² , and the power density during the formation of the third dielectric layer is preferably 0.2 to 10 W / cm ² .

(Other processes)
After the transparent film 10 is heated, a process other than the formation of the transparent dielectric layer 20 may be included until the transparent electrode layer 30 is formed. For example, after the transparent film 10 is heated, a process of exposing the film surface to plasma (bombarding process) may be performed. Sputtering is performed using a target such as SUS in the presence of an inert gas such as argon to generate plasma, thereby cleaning the film surface and suppressing the generation of a gas having a mass number of 28 when forming a transparent electrode layer. It is thought that it is done. When the transparent dielectric layer 20 is formed before the transparent electrode layer 30 is formed, the bombarding process may be performed either before or after the transparent dielectric layer 20 is formed.

[Physical properties of substrates with transparent electrodes]
The substrate 50 with a transparent electrode of the present invention obtained as described above preferably has a heat shrinkage ratio of 0.4% or less, more preferably 0.35% or less, and 0.3% or less. Is more preferable. When the heat shrinkage rate varies depending on the direction (when it differs between the MD direction and the TD direction), the heat shrinkage rate in the MD direction may be in the above range. In particular, it is preferable that the thermal shrinkage rate in both the MD direction and the TD direction is in the above range.

Moreover, the thermal shrinkage starting temperature of the substrate 50 with a transparent electrode of the present invention is preferably 85 ° C. or higher, more preferably 90 ° C. or higher, and further preferably 100 ° C. or higher. Ideally, the substrate with a transparent electrode does not exhibit a thermal shrinkage start temperature in the range up to 200 ° C.

In the present invention, the heat shrinkage rate and the heat shrinkage start temperature can be set within the above ranges by shrinking the film in the heating step. In addition, by using a film having a low heat shrinkage rate and a high heat shrinkage start temperature as the transparent film 10 used for the production of the substrate with a transparent electrode, the heat shrinkage rate of the substrate with the transparent electrode is further reduced, and the heat shrinkage start temperature is set to It can be further increased. If the heat shrinkage rate and the heat shrinkage start temperature are within the above ranges, the dimensional change when the substrate with the transparent electrode is heated is suppressed in the crystallization of the transparent electrode layer and the subsequent touch panel formation process. The design can be expected to be easy.

寸法 By suppressing the dimensional change due to heating, when the transparent electrode layer is patterned, the generation of wrinkles along the pattern boundary tends to be suppressed. According to the study by the present inventors, wrinkles occur at the pattern boundary of the transparent electrode layer even when a film having a small heating dimensional change rate is used as the transparent film 10 before forming the transparent electrode layer 30. There was a case. Therefore, it is considered that the generation of wrinkles when the transparent electrode layer is patterned is not caused only by the dimensional change of the transparent film 10.

As described above, in the present invention, generation of wrinkles along the pattern boundary of the transparent electrode layer is suppressed by non-contact heating of the transparent film in the sputtering film forming apparatus before forming the transparent electrode layer. The One of the reasons that the generation of wrinkles is suppressed is that the state of the film forming interface changes due to the heat treatment before forming the transparent electrode layer, and the stress applied to the transparent electrode layer is reduced during heating for crystallization. It is estimated to be.

When the transparent electrode layer 30 of the substrate 50 with a transparent electrode of the present invention is a metal oxide thin film mainly composed of amorphous indium oxide, the substrate with a transparent electrode is heated at 150 ° C. for 30 minutes, the ratio _d out _{/ d in} the lattice spacing _{d in} the are (222) surfaces obtained by surface separation _{d out} and in-plane X ray diffraction measurement is (222) plane obtained by out-plane X ray diffraction measurement of the indium oxide crystal Is preferably close to 1. Specifically, d _out / d _in is preferably 0.998 to 1.003, and more preferably 0.999 to 1.002. d _out / d _in is an index representing the three-dimensional strain of the crystal, and the more d _out / d _in is from 1, the more the crystal structure is distorted.

The transparent electrode layer of the substrate with a transparent electrode of the present invention is amorphous (may contain a part of crystalline component), but is heated at 150 ° C. for 30 minutes, so that the metal in the transparent electrode layer The oxide is crystallized. The fact that d _out / d _in after being heated at 150 ° C. for 30 minutes is close to 1, the stress applied to the film is small when the transparent electrode layer is crystallized. This is considered to indicate that the residual stress is small. When the residual stress of the transparent electrode layer after crystallization is small, the stress at the interface between the transparent electrode layer and the transparent film is small, so it is estimated that the generation of wrinkles when the transparent electrode layer is patterned is suppressed Is done.

The crystal spacing is determined by X-ray diffraction. The diffraction angle 2θ of the (222) plane after the substrate with a transparent electrode is heated at 150 ° C. for 30 minutes is preferably 32 ° or less, more preferably 31 ° or less, and further preferably 30.8 ° or less. In order to determine the interplanar spacing of crystals, Cu · Kα rays (wavelength: 0.15418 nm) are used as an X-ray source, and X-ray diffraction is performed under conditions of an incident angle of 0.1 ° to 2.0 °.

Diffraction angle 2θ of (440) plane measured by X-ray diffraction using Cu · Kα ray X-ray source after substrate with transparent electrode is heated at 150 ° C. for 30 minutes, and (440) plane before heating the difference 2 [Theta]-2 [Theta] ₀ and the diffraction angle 2 [Theta] ₀ in is preferably 0.50 or less, more preferably 0.45 or less, still more preferably 0.32 or less, 0.28 or less It is particularly preferred that When the change in diffraction angle is small before and after heating for crystallization, it is considered that the stress applied to the transparent electrode layer during crystallization is small and no residual stress is generated in the transparent electrode layer. Therefore, when 2θ−2θ ₀ is small, it is considered that generation of wrinkles when the transparent electrode layer is patterned is suppressed.

[Use of substrates with transparent electrodes]
The board | substrate with a transparent electrode of this invention can be used as transparent electrodes, such as a display, a light emitting element, a photoelectric conversion element, and is used suitably as a transparent electrode for touchscreens. Among these, it is preferably used for a capacitive touch panel.

In application to a touch panel, the substrate 50 with a transparent electrode is preferably subjected to a heat treatment so that the transparent electrode layer is crystallized. The heat treatment for crystallization is performed, for example, in an oven at 120 ° C. to 150 ° C. for 30 to 60 minutes. Alternatively, it may be heated at a relatively low temperature for a long time, such as at 85 to 120 ° C. for 1 to 3 days. The heat treatment of the transparent electrode layer may be performed either before or after patterning of the transparent electrode layer. Further, the heat treatment of the transparent electrode layer may also serve as a heat annealing treatment for touch panel formation such as heat treatment at the time of forming the lead wiring.

The substrate 50 with a transparent electrode is used by patterning the transparent electrode layer 30 into an electrode forming part 30a and an electrode non-forming part 30b. For example, after the transparent electrode layer is formed, the patterning is performed by removing the transparent electrode layer in a part of the surface by etching or the like.

The etching method of the transparent electrode layer may be either a wet process or a dry process, but a wet process is suitable from the viewpoint that only the transparent electrode layer 30 is easily removed selectively. In the substrate with a transparent electrode of the present invention, wrinkles along the pattern hardly occur after the transparent electrode layer is patterned. Therefore, it is difficult to visually recognize the pattern, and the visibility of the screen can be improved.

In the formation of the touch panel, a conductive ink or paste is applied on a substrate with a transparent electrode, and heat treatment is performed, whereby a collecting electrode as a wiring for a routing circuit is formed. The method for the heat treatment is not particularly limited, and examples thereof include a heating method using an oven or an IR heater. The temperature and time of the heat treatment are appropriately set in consideration of the temperature and time at which the conductive paste adheres to the transparent electrode. For example, examples include heating at 120 to 150 ° C. for 30 to 60 minutes for heating by an oven and heating at 150 ° C. for 5 minutes for heating by an IR heater. In addition, the formation method of the circuit wiring is not limited to the above, and may be formed by a dry coating method. In addition, since the wiring for the routing circuit is formed by photolithography, the wiring can be thinned.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

The film thickness of each dielectric layer and transparent electrode layer was determined by observation with a transmission electron microscope (TEM) of a cross section of the substrate with a transparent electrode.

The heat shrinkage rate was determined by measuring the distance L ₀ between the two points before the 30 minute heating at 150 ° C. and the distance L between the two points after heating by three-dimensional measurement. It was determined by measuring with a vessel.

[Example 1]
As the transparent film, a PET film having a thickness of 125 μm in which hard coat layers (refractive index of 1.53) made of urethane resin were formed on both surfaces was used. The heat shrinkage rate of the PET film when heated at 150 ° C. for 30 minutes was 0.73% in the MD direction and 0.56% in the TD direction. This transparent film was introduced into a winding type sputtering film forming apparatus schematically shown in FIG.

Thereafter, the pressure in the base material preparation chamber was once reduced to 5 × 10 ⁻⁴ Pa, and then the film was heated while the film was transported at a pressure of 0.5 Pa in the base material preparation chamber. The temperature of the heater in the base material preparation chamber 201 was 240 ° C., and the temperature of the film surface measured by a thermolabel attached to the film surface was 82 ° C. The heating time (time during which the film was conveyed between the heaters) was 20 seconds.

The transparent film after the heat treatment is continuously conveyed to the film forming chamber, and on the film forming roll 260, SiO _x as the first transparent dielectric layer, Nb ₂ O ₅ as the second transparent dielectric layer, and the third dielectric SiO ₂ as a layer and ITO as a transparent electrode layer were sequentially formed. The substrate temperature during film formation was −20 ° C.

The first dielectric layer uses B—Si as a target and introduces an oxygen / argon (20 sccm / 400 sccm) mixed gas into the film forming chamber, while the apparatus pressure is 0.2 Pa and the power density is 1.4 W / cm ² . The film was formed under conditions. The second dielectric layer uses niobium (Nb) as a target and introduces an oxygen / argon (160 sccm / 1600 sccm) mixed gas into the film forming chamber, while the apparatus pressure is 0.87 Pa, the substrate temperature is −20 ° C., and the power density is The film was formed under conditions of 8.1 W / cm ² . The third dielectric layer uses B—Si as a target, and introduces a mixed gas of oxygen / argon (190 sccm / 400 sccm) into the apparatus, while the apparatus pressure is 0.2 Pa and the power density is 10.2 W / cm ² . Was formed into a film.

The transparent electrode layer uses a sintered target of indium oxide and tin oxide, and an oxygen / argon (2 sccm / 1000 sccm) mixed gas is introduced into the apparatus while the apparatus pressure is 0.4 Pa and the power density is 5.2 W / cm ^2. Made under the conditions of The ratio P ₂₈ / P _I of the partial pressure P ₂₈ of the gas having a mass number of 28 to the partial pressure P _I of the inert gas (argon gas) in the film forming chamber was 4.7 × 10 ⁻⁴ . Thus, the board | substrate with a transparent electrode provided with a dielectric material layer and a transparent electrode layer on the transparent film was obtained.

(Evaluation of crystal characteristics by X-ray diffraction)
This substrate with a transparent electrode was heated in an oven at 150 ° C. for 30 minutes to crystallize the transparent electrode layer. The ratio d _out / d _in of the interplanar spacing d _{in in} -plane measurement and the (222) plane spacing d _out _in out-plane measurement of the film with a transparent electrode after crystallization was measured. Met. The difference 2θ-2θ _{0 in} the diffraction angle of the (440) plane was 0.30 °.

X-ray diffraction was measured using an X-ray diffraction measurement apparatus (“SmartLab” manufactured by Rigaku) equipped with Cu · Kα rays as an X-ray source. Measurement of the distance between planes in the direction parallel to the film surface (out-plane measurement) is performed using a thin film measurement method (2θ measurement) with an axis of symmetry ω of 0.4 ° (center of origin), an X-ray intensity of 45 kV · 200 mA, angle range. The measurement was performed under the conditions of 2θ = 25 ° to 62 °, a scanning speed of 1.000 ° / min, and a sampling interval of 0.0400 °. In the measurement of the surface interval in the direction perpendicular to the film surface (in-plane measurement), the scanning speed is changed to 0.400 ° / min and the sampling interval is changed to 0.0400 °, and the angle of ω is the same as that in the out-plane measurement. The measurement was carried out at the same angle as.

[Example 2]
Since the temperature of the heater was changed to 400 ° C. and the heating time by the heater was changed to 25 seconds, the film surface temperature in the heat treatment was 90 ° C. Further, the internal pressure of the first dielectric layer and the third dielectric layer was changed to 0.1 Pa. Except these changes, it carried out similarly to the said Example 1, and obtained the board | substrate with a transparent electrode. In Example 2, the film thickness (deposition) of the transparent dielectric layer and the transparent electrode layer was changed to adjust the film thickness of each layer to be the same as in Example 1. This substrate with a transparent electrode was crystallized in the same manner as in Example 1, and the (222) plane spacing ratio d _out / d _in was measured to be 0.999.

[Example 3]
By reducing the film conveyance speed, the heating time by the heater was quadrupled, and accordingly, the film surface temperature in the heat treatment was 99 ° C. Others were the same as in Example 1 to obtain a substrate with a transparent electrode. In Example 3, the film thickness of each layer was adjusted to be the same as that in Example 1 by changing the film formation (deposition) speeds of the transparent dielectric layer and the transparent electrode layer. This substrate with a transparent electrode was crystallized in the same manner as in Example 1, and the (222) plane spacing ratio d _out / d _in was measured to be 0.998.

[Examples 4 and 5]
In Example 4, as a transparent film, a PET film having a thickness of 125 μm in which a hard coat layer (refractive index of 1.53) made of urethane resin is formed on both surfaces is heat-treated before being introduced into a film forming apparatus, Low heat shrinkage rate. In Example 5, a PET film having a lower thermal shrinkage rate was obtained by heating the PET film at a higher temperature than in Example 4.

These low thermal shrinkage PET films were used as transparent films. Otherwise, in the same manner as in Example 1, a dielectric layer and a transparent electrode layer were formed. The substrate with a transparent electrode obtained in Example 5 was crystallized in the same manner as in Example 1, and then the (222) plane spacing ratio d _out / d _in was measured to be 0.999. .

[Example 6]
The thickness of the transparent film on which the hard coat layer was formed was changed to 100 μm, and the heater temperature was changed to 230 ° C., so that the film surface temperature in the heat treatment was 85 ° C. Others were carried out similarly to the said Example 1, and obtained the board | substrate with a transparent electrode. This substrate with a transparent electrode was crystallized in the same manner as in Example 1, and the ratio d _out / d _in of the (222) plane spacing d _out was measured and found to be 1.000.

[Comparative Example 1]
Heating before film formation was not performed with the heater turned off. Others were carried out similarly to the said Example 1, and obtained the board | substrate with a transparent electrode. The ratio P ₂₈ / P _I of the partial pressure P ₂₈ of the mass number 28 gas to the partial pressure P _I of the inert gas (argon gas) in the film forming chamber of the transparent electrode layer was 5.7 × 10 ⁻³ . .

[Comparative Example 2]
Heating before film formation was not performed with the heater turned off. Others were carried out similarly to the said Example 4, and obtained the board | substrate with a transparent electrode.

[Comparative Example 3]
Since the temperature of the heater was changed to 120 ° C., the film surface temperature in the heat treatment was 60 ° C. Others were carried out similarly to the said Example 4, and obtained the board | substrate with a transparent electrode.

[Comparative Example 4]
After the transparent film is introduced into the wind-up type sputtering film forming apparatus and the pressure in the substrate preparation chamber is reduced to 5 × 10 ⁻⁴ Pa, the film forming roll is adjusted to a temperature of 70 ° C. The film was conveyed at a pressure of 0.5 Pa, and the transparent film was heated by the heat from the film forming roll. At this time, no film was formed on the transparent film, and the heated film was once wound up by a winding roll in the base material preparation chamber. The film surface temperature during the heat treatment with the film forming roll was 40 ° C.

[Comparative Example 5]
In the state where the film forming roll was adjusted to 80 ° C., heating of the transparent film on the film forming roll was attempted in the same manner as in Comparative Example 4, but the transport tension became unstable, and the winding body was significantly wound. As a result, subsequent film formation could not be performed.

[Evaluation]
(Evaluation of pattern 皺)
A 10 cm square sheet-like film was cut out from the film with a transparent electrode obtained in each Example and Comparative Example (excluding Comparative Example 5). The cut film was heated in an oven at 150 ° C. for 30 minutes, and the transparent electrode layer was crystallized.

After that, patterning of the transparent electrode layer was performed by photolithography. First, a photoresist (product name: TSMR-8900 (manufactured by Tokyo Ohka Kogyo Co., Ltd.)) was applied on the transparent electrode layer to a thickness of about 2 μm by spin coating, and then prebaked in an oven at 90 ° C. 40 mJ ultraviolet light was irradiated through the photomask. Thereafter, the photoresist layer was post-baked at 110 ° C. and then patterned using a developer (product name: NMD-W (manufactured by Tokyo Ohka Kogyo Co., Ltd.)). Further, the transparent electrode layer was etched using an etching solution (product name: ITO02 (manufactured by Kanto Chemical)). Finally, the remaining photoresist was removed using a rinse solution (product name 104 (manufactured by Tokyo Ohka Kogyo Co., Ltd.)).

The presence / absence of pattern defects in the transparent electrode layer was evaluated by visual inspection. The reflected light from the fluorescent lamp is observed in a state where the pattern formation direction of the transparent electrode layer and the reflected light of the straight tube fluorescent lamp are substantially orthogonal, and the reflected image of the fluorescent lamp looks linear A is E (no wrinkles), and E is a reflection image that appears to be significantly distorted. The thermal shrinkage rate of the transparent film used in the production of the transparent electrode-coated substrates of the examples and comparative examples, the heating temperature in the heating step, the heating time and the film surface temperature, the production of the silicon oxide film in the transparent dielectric layer Table 1 shows the film pressure, the thermal contraction rate of the substrate with a transparent electrode, and the evaluation results of wrinkles by visual observation.

From the results in Table 1, it is possible to suppress the generation of wrinkles when the transparent electrode layer is patterned by heating with a non-contact heater before forming the transparent dielectric layer and the transparent electrode layer. Recognize. From the comparison between Example 1 and Example 3 and Comparative Example 3, it is understood that wrinkles of the substrate with a transparent electrode are further suppressed by increasing the heating temperature. In addition, in comparison with Example 2 and Example 3, in addition to the high surface temperature of the film, when the film-forming pressure of the silicon oxide layer as the dielectric layer is low, the wrinkles of the substrate with transparent electrodes It turns out that it is suppressed further. The same tendency is observed from the comparison between Example 1 and Example 6.

Further, from the comparison between Example 1 and Example 4 and Example 5, as a transparent film before being introduced into the sputtering film forming apparatus, a film having a small amount of heat shrinkage is used. It can be seen that wrinkles are further suppressed.

On the other hand, in Comparative Example 2, a transparent film having a low heat shrinkage similar to that in Example 4 is used. However, since heat treatment was not performed before film formation, generation of wrinkles was observed on the substrate with a transparent electrode. It was. From these results, it can be seen that the use of a low heat shrinkage substrate alone does not sufficiently suppress wrinkles, and it is important that a heating step is performed before film formation.

In Comparative Example 4 in which heating was performed on the film-forming roll by rewinding the transparent film in the wind-up type sputtering film-forming apparatus, generation of wrinkles on the substrate with the transparent electrode could not be suppressed. From the above results, it can be seen that in the present invention, generation of soot is suppressed by non-contact heating at a high temperature for a short time.

In addition, since the transparent electrode layer of each example has a ratio d _out / d _in of the in-plane measurement and the out-plane measurement of the (222) plane spacing after crystallization close to 1, the crystallized by heating. It can be seen that the distortion of the crystal of indium oxide after being converted is small. From these results, in the substrate with a transparent electrode according to the present invention, a predetermined heat treatment is performed before forming the transparent electrode layer, so that distortion due to stress applied to the transparent electrode layer during crystallization of the transparent electrode layer is achieved. It is considered that the generation of wrinkles when the transparent electrode layer is patterned is suppressed because the occurrence of the above is suppressed and the stress at the interface between the transparent electrode layer and the film is small.

DESCRIPTION OF SYMBOLS 10 Transparent film 11

Base film

12, 13 Hard-coat layer 20 Transparent dielectric layer 21-23 Transparent dielectric layer 30 Transparent electrode layer 30a Electrode formation part 30b Electrode non-formation part 50 Substrate with a transparent electrode 200 Sputter film forming apparatus 201 Base

material Preparation chamber

202, 203 Film forming chamber 260 Film forming roll 261 Feeding roll 262 Winding roll 271 to 274 Heating section

Claims

A method for producing a substrate with a transparent electrode comprising a transparent electrode layer made of a metal oxide thin film on a transparent film using a winding-type sputtering film-forming apparatus,
The winding type sputtering apparatus includes a base material preparation chamber and a film forming chamber, and a heating unit is provided in the base material preparation chamber,
A base material preparation step in which the roll-shaped wound body of the transparent film is introduced into the base material preparation chamber of the wind-up type sputtering film forming apparatus;
A heating step in which the transparent film is heat-treated at a surface temperature of 80 ° C. to 160 ° C. by heat from the heating unit while being fed and conveyed from the roll-shaped wound body in the base material preparation chamber; Transparent electrode layer film formation in which a transparent electrode layer made of an amorphous metal oxide thin film is formed on the transparent film after heat treatment while an inert gas is introduced into a film forming chamber of a pre-sputter film forming apparatus Having a process,
The heating step and the transparent electrode layer film forming step are continuously performed without taking out the transparent film from the winding type sputtering film forming apparatus,
In the heating step, the heat treatment is performed without contact between the transparent film and the heating unit, and the pressure in the base material preparation chamber in the heating step is 1.0 Pa or less. .
The substrate with a transparent electrode according to claim 1, wherein the transparent electrode layer forming step is continuously performed in the film forming chamber after the heating step and before the transparent film after the heat treatment is wound in a roll shape. Manufacturing method.
The method for producing a substrate with a transparent electrode according to claim 1 or 2, wherein in the heating step, the heating time of the transparent film is 0.1 second to 600 seconds.
The method for producing a substrate with a transparent electrode according to any one of claims 1 to 3, wherein, in the heating step, the temperature of the heating section is 150 ° C to 500 ° C.
In the transparent electrode layer deposition step, the ratio P 28 / P I of the partial pressure P 28 of the gas having a mass number of 28 to the partial pressure P I of the inert gas in the deposition chamber is 5 × 10 −4 or less. The method for producing a substrate with a transparent electrode according to any one of claims 1 to 4.
In the base material preparation chamber of the winding type sputtering film forming apparatus, a plurality of heating units are provided along the film conveying direction, and a conveying roll is provided between the heating units,
The method for producing a substrate with a transparent electrode according to any one of claims 1 to 5, wherein the heat treatment is performed by heat from the plurality of heating units.
Between the heating step and the transparent electrode layer forming step, further comprising a transparent dielectric layer forming step,
The production of a substrate with a transparent electrode according to any one of claims 1 to 6, wherein in the transparent dielectric layer forming step, at least one transparent dielectric layer is formed on the transparent film by a sputtering method. Method.
The method for producing a substrate with a transparent electrode according to claim 7, wherein a dielectric layer comprising at least one silicon oxide layer is formed in the transparent dielectric layer forming step.
In the transparent dielectric layer forming step, the first transparent dielectric layer having a refractive index of 1.45 to 1.95, the second transparent dielectric layer having a refractive index of 2.00 to 2.35, and silicon oxide The manufacturing method of the board | substrate with a transparent electrode of Claim 7 in which the 3rd transparent dielectric material layer which consists of is formed in this order on the said transparent film.
The transparent dielectric layer formed immediately below the transparent electrode layer in the transparent dielectric layer forming step is formed at a film forming pressure of 0.4 Pa or less, according to any one of claims 7 to 9. Manufacturing method of substrate with transparent electrode.
11. The transparent film introduced into the sputtering film forming apparatus in the base material preparation step has a thermal shrinkage rate in the MD direction of 0.4% or less when heated at 150 ° C. for 30 minutes. The manufacturing method of the board | substrate with a transparent electrode of Claim 1.
The transparent film introduced into the sputtering film forming apparatus in the base material preparation step has a heat shrinkage starting temperature measured by thermomechanical analysis of 85 ° C or higher, according to any one of claims 1 to 11. Manufacturing method of substrate with transparent electrode.