JP2018097576A - Wiring for connection and forming method of wiring for connection - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide, when forming a wiring for connection which electrically connects a conductive pattern for electrodes on a circuit board to an external connecting terminal by using photosensitive silver pastes or photosensitive conductive films, a wiring for connection and a forming method of the wiring for connection that can drastically improve the connecting reliability while suppressing an increasing resistance value even when exposed under a reliability test condition (85°C85%RH) for a prolonged period of time.SOLUTION: A wiring for connection relating to the present invention is used to electrically connect a conductive pattern for electrodes on a circuit board and an external terminal and is formed by withdrawing from the conductive pattern for electrodes. The wiring for connection is formed by using photosensitive silver pastes or photosensitive conductive films and has the content of CI ion included in the photosensitive layer of the photosensitive sliver pastes or the photosensitive conductive films is equal to or less than 500 ppm.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a connection wiring and a connection wiring formation method using a photosensitive conductive film or a photosensitive silver paste. More specifically, the present invention relates to a wiring for connection with electrodes of devices such as flat panel displays such as liquid crystal display elements, touch screens, and solar cells, and a method for forming the wiring for connection.

  Liquid crystal display elements and touch screens are used in large electronic devices such as personal computers and televisions, small electronic devices such as car navigation, mobile phones, and electronic dictionaries, and display devices such as OA devices and FA devices. In these liquid crystal display elements, touch screens, solar cells, and other devices, a transparent conductive film is used as part of transparent wiring, pixel electrodes, or terminals.

  As a material for the transparent conductive film, ITO (Indium-Tin-Oxide), indium oxide, tin oxide, or the like has been conventionally used since it exhibits high transmittance for visible light. In an electrode such as a substrate for a liquid crystal display element, a pattern obtained by patterning a transparent conductive film made of the above-described material has become mainstream.

  As a method for patterning a transparent conductive film, a method of forming a transparent electrode by forming a transparent conductive film, forming a resist pattern by photolithography, removing a predetermined portion of the transparent conductive film by wet etching, and forming a transparent electrode is generally used. is there. In the case of an ITO and indium oxide film, a mixed liquid composed of two liquids of hydrochloric acid and ferric chloride is generally used as the etching liquid.

  The ITO film and the tin oxide film are generally formed by sputtering. However, in this method, the properties of the transparent conductive film are likely to change depending on the difference in sputtering method, sputtering power, gas pressure, substrate temperature, type of atmospheric gas, and the like. Differences in the film quality of the transparent conductive film due to fluctuations in sputtering conditions cause variations in the etching rate when the transparent conductive film is wet-etched, and are liable to reduce product yield due to patterning defects. Moreover, since the said transparent electrode formation method has passed through the sputtering process, the resist formation process, and the etching process, the process is long and has become a big burden also in terms of cost.

  In recent years, attempts have been made to form transparent electrodes using materials in place of ITO, indium oxide, tin oxide and the like in order to solve the above-mentioned problems.

  The following Patent Document 1 includes a photosensitive conductive film comprising a support film, a conductive layer containing conductive fibers provided on the support film, and a photosensitive resin layer provided on the conductive layer. A method of forming an electrode is disclosed in which a photosensitive resin layer is laminated on a substrate so that the photosensitive resin layer is in close contact, and then exposed and developed. This method makes it possible to form an electrode having sufficient adhesion to the substrate and having a small surface resistivity with sufficient resolution by a simple process.

  Further, in Patent Document 2 below, the first exposure is performed by using a two-step exposure method in which the first exposure is performed through the support film and the second exposure is performed in the presence of oxygen from which the support film is removed. The part light-shielded with the mask in the process becomes the resin cured layer, and the part irradiated with light without shielding with the mask in the first exposure process becomes the electrode, and a technique for reducing the height difference between the electrode part and the resin cured layer is disclosed. Yes.

International Publication No. 2010/021224 International Publication No. 2013/051516

  By the way, with respect to a substrate in which an electrode is formed of the photosensitive conductive film described in Patent Documents 1 and 2, a lead-out wiring (hereinafter also referred to as “connection wiring”) for connecting the electrode and an external connection terminal. It is conceivable to use a photosensitive silver paste or a photosensitive conductive film. However, when such a lead-out wiring is used, reliability test conditions (temperature 85 ° C., relative humidity 85% RH: hereinafter, “85 ° C. 85% RH "). After standing under, there was a problem that the resistance value increased and connection failure occurred.

  The present invention has been made in view of the problems of the prior art, and a connection wiring for electrically connecting an electrode on a substrate and an external connection terminal is formed by a photosensitive silver paste or a photosensitive conductive film. Of connection wiring and connection wiring that can suppress an increase in resistance value even if left for a long time under reliability test conditions (85 ° C. and 85% RH) and can greatly improve connection reliability. A forming method is provided.

The present invention relates to the following.
(1) A connection wiring formed by pulling out an electrode on a substrate and an external connection terminal, wherein the connection wiring is a photosensitive silver paste or a photosensitive conductive film. A wiring for connection, which is formed by the above, and the content of Cl ions contained in the photosensitive layer of the photosensitive silver paste or the photosensitive conductive film is 500 ppm or less.
(2) The photosensitive conductive film is a photosensitive conductive film having the support film, a conductive layer provided on the support film, and a photosensitive layer provided with a photosensitive resin layer provided on the conductive film. The wiring for connection according to claim 1, wherein the photosensitive resin layer contains (a) a binder polymer, (b) a photopolymerizable compound, and (c) a photopolymerization initiator.
(3) The photosensitive layer has a light transmittance of 80% or more in a wavelength region of 450 to 650 nm when the total thickness of the conductive film and the photosensitive resin layer is 1 to 30 μm. Connection wiring as described.
(4) The wiring for connection according to claim 2 or 3, wherein the conductive film contains conductive fibers.
(5) The connection wiring according to claim 4, wherein the conductive fibers are silver fibers.
(6) A method for forming a connection wiring according to any one of (1) to (5), comprising a step of applying the photosensitive silver paste by a dispenser coating method or a screen printing method. Method for forming wiring.
(7) A method for forming a connection wiring according to any one of (1) to (5), wherein the photosensitive conductive film is laminated so as to adhere to the substrate; An exposure step of irradiating a predetermined portion of the photosensitive layer of the photosensitive conductive film with actinic rays, and a development step of forming the connection wiring by developing an unexposed portion of the photosensitive layer after exposure. A method of forming connection wiring.
(8) A method for forming the connection wiring according to any one of (1) to (5), wherein the photosensitive conductive film is laminated so that the photosensitive resin layer is in close contact with the substrate. And an exposure step of irradiating a predetermined portion of the photosensitive resin layer on the substrate with actinic rays, and after peeling the support film, developing the exposed photosensitive resin layer and an unexposed portion of the conductive film And a developing step for forming the connection wiring.
(9) A method for forming a wiring pattern of a wiring for connection with an electrode according to any one of (1) to (5), wherein the photosensitive resin layer is formed on a substrate. Laminating in close contact, a first exposure step of irradiating a predetermined portion of the photosensitive resin layer on the substrate with actinic rays, and after peeling the support film, in the presence of oxygen, the first A second exposure step of irradiating a part or all of the unexposed portion in the exposure step with an actinic ray; and after the second exposure step, developing the photosensitive resin layer and the conductive film for the connection. And a developing step for forming the wiring.

  According to the present invention, when the connection wiring for electrically connecting the electrode on the substrate and the external connection terminal is formed by the photosensitive silver paste or the photosensitive conductive film, the reliability test condition (85 ° C. and 85% RH). ) It is possible to provide a connection wiring and a method for forming the connection wiring that can suppress an increase in resistance value and can greatly improve connection reliability even when left under a long time.

It is a model top view which shows an example of an electrostatic capacitance type touch panel sensor. It is a schematic cross section which shows one Embodiment of the photosensitive conductive film used by this invention. It is a partially cutaway perspective view which shows one Embodiment of the photosensitive conductive film used by this invention. It is a schematic cross section for demonstrating one Embodiment of the formation method of the wiring for connection of this invention. It is a schematic cross section for demonstrating another embodiment of the formation method of the wiring for connection of this invention. It is a schematic cross section for demonstrating another embodiment of the formation method of the wiring for connection of this invention. It is a schematic diagram for demonstrating an example of the manufacturing method of the touch panel sensor shown by FIG. FIG. 2 is a partial cross-sectional view taken along line a-a ′ shown in FIG. 1. FIG. 2 is a partial sectional view taken along line b-b ′ shown in FIG. 1. It is a figure which shows the wiring for a connection formed in the Example and comparative example of this invention.

  Hereinafter, embodiments for carrying out the present invention will be described in detail. However, the present invention is not limited to the following embodiments. In the present specification, “(meth) acrylic acid” means acrylic acid or methacrylic acid, and “(meth) acrylate” means acrylate or a corresponding methacrylate. “A or B” only needs to include one of A and B, or may include both. In addition, the exemplary materials may be used alone or in combination of two or more unless otherwise specified. In the present specification, numerical ranges indicated using “to” indicate ranges including the numerical values described before and after “to” as the minimum value and the maximum value, respectively. Further, in the present specification, the term “layer” includes a configuration formed in a part in addition to a configuration formed in the entire surface when observed as a plan view.

<Connection wiring>
One embodiment of the connection wiring of the present invention will be described with reference to the example of the touch panel sensor shown in FIG. The connection wiring of the present embodiment is a connection wiring formed by being drawn out from the electrode in order to make an electrical connection between the electrode on the substrate and the external connection terminal, and the connection wiring is photosensitive. The connection wiring is formed of a silver paste or a photosensitive conductive film, and a Cl ion content contained in a photosensitive layer of the photosensitive silver paste or the photosensitive conductive film is 500 ppm or less. Here, the “electrode” refers to a transparent electrode, a pixel electrode, or a connection electrode used for connecting these electrodes to a connection wiring, which is used in a device such as a liquid crystal display element, a touch screen, or a solar cell. The “connection wiring” refers to wiring provided for electrically connecting electrodes or electrodes and external connection terminals. The “external connection terminal” refers to a terminal for electrical connection with an external circuit or the like. The “conductor pattern” to be described later refers to a patterned conductor such as “electrode”, “connection wiring”, “external connection terminal” and the like that is electrically conductive.

  Hereinafter, the connection wiring of the present embodiment will be described more specifically. FIG. 1 is a schematic top view illustrating an example of a capacitive touch panel sensor. The touch panel sensor shown in FIG. 1 includes transparent electrodes 103 and 104 and a connection electrode 106 on a substrate (transparent substrate 101). The touch panel sensor shown in FIG. 1 has a touch screen 102 (a portion surrounded by a dotted line in FIG. 1) for detecting a touch position on one side of a transparent substrate 101, and detects a change in capacitance in this region. A transparent electrode 103 having X position coordinates and a transparent electrode 104 having Y position coordinates are provided. These transparent electrodes 103 and 104 can be formed using a photosensitive conductive film used in the present invention, as will be described later. A connection electrode 106 is disposed on a part of the transparent electrodes 103 and 104, and the connection electrode 106 is electrically connected to one end of a connection wiring (lead-out wiring) 105. The other end of the connection wiring 105 is electrically connected to the external connection terminal 107. That is, the connection wiring 105 is a wiring that electrically connects the connection electrode 106 of the transparent electrodes 103 and 104 and the external connection terminal 107. The external connection terminal 107 is an electrode for connecting to a driver element circuit (not shown) that controls an electrical signal as a touch panel.

  The connection wiring 105 according to the present invention corresponds to a so-called lead-out wiring that electrically connects electrodes. That is, in the present embodiment, the wiring is formed by being drawn from the connection electrode 106 of the transparent electrodes 103 and 104 in order to make an electrical connection with the external connection terminal 107. The connection wiring 105 is formed of a photosensitive silver paste or a photosensitive conductive film.

<Formation of connection wiring>
The photosensitive silver paste is used in a state of being stored in a dispenser, for example. Connected to the dispenser are a pressure control device for controlling the discharge pressure, a drive device that can move the nozzle position of the dispenser to a desired position on the XY axis on the plane, and a Z axis perpendicular thereto, an automatic control device, and the like. The photosensitive silver paste is discharged along the pattern shape of the connection wiring 105 from the nozzle of the dispenser. Thereafter, the photosensitive silver paste formed in a desired wiring shape is cured by irradiating actinic rays such as ultraviolet rays and electron beams. If necessary, curing of the photosensitive silver paste may be promoted by heat curing.

  The photosensitive silver paste can be applied with a predetermined thickness by a screen printing method. In the screen printing, an opening is formed in advance along the connection wiring 105. After application by screen printing, the photosensitive silver paste formed in a desired wiring shape is cured by irradiating with actinic rays such as ultraviolet rays and electron beams. Also in this case, heat curing may be added as necessary.

  When using the photosensitive conductive film, usually, a step of laminating the photosensitive conductive film so as to be in close contact with the substrate, and irradiating a predetermined portion of the photosensitive layer of the photosensitive conductive film on the substrate with actinic rays. The connection wiring with the electrode is formed by a method comprising: an exposure step to perform; and a development step to form a connection wiring with the electrode by developing an unexposed portion of the photosensitive layer after the exposure. As the photosensitive conductive film, one having a conductive photosensitive layer is used.

  As described above, the wiring 105 formed of the photosensitive silver paste or the photosensitive conductive film is likely to have a problem that the connection reliability is lowered during long-term use. The occurrence of this problem is that the connection portions between the electrodes 103 and 104 and the connection wiring 105 and the connection portions between the connection wiring 105 and the external connection terminal 107 are weak in the external environment, particularly in a high temperature and high humidity environment. This is due to the fact that the connection wiring 105 is formed near the outer periphery of the panel and is easily affected by the humidity of the external environment.

  Accordingly, the present inventors have studied in detail the factors that reduce connection reliability. As a result, it has been found that Cl ions, which are ionic impurities mixed in the photosensitive silver paste or the photosensitive layer of the photosensitive conductive film constituting the connection wiring, are the main factors that lower the connection reliability. The present invention has been made on the basis of this finding. By selecting a material having a low Cl ion as the photosensitive silver paste or photosensitive conductive film, it is left for a long time under a severe condition of 85 ° C. and 85% RH. Even so, it was found that the increase in resistance can be suppressed and the connection reliability can be improved.

<Cl ion content>
In the present invention, in order to improve connection reliability, it is necessary that the content of Cl ions contained in the photosensitive layer of the photosensitive silver paste or the photosensitive conductive film be 500 ppm or less. If the Cl ion content is 500 ppm or less, an increase in wiring resistance value can be suppressed over a long period of time even in a high temperature and high humidity environment. For example, since a very stable resistance value can be maintained even after being left for 1000 hours or more under the severe conditions of 85 ° C. and 85% RH, which are generally adopted as test conditions for performing reliability evaluation, connection reliability can be maintained. It is possible to improve the performance. However, when the Cl ion content exceeds 500 ppm, the increase in the wiring resistance value exceeds 20% in a shorter time under the condition of 85 ° C. and 85% RH, and the connection reliability is greatly reduced. It is done.

  In the present invention, the Cl ion content is measured by combustion ion chromatography. Combustion ion chromatography is a method of burning in a combustion gas stream containing oxygen, collecting the generated gas in an absorption liquid, and separating and quantifying the Cl collected in the absorption liquid by ion chromatography. is there.

<Photosensitive conductive film>
FIG. 2 is a schematic cross-sectional view showing an embodiment of the photosensitive conductive film used in the present invention. FIG. 3 is a partially cutaway perspective view of the embodiment.
The photosensitive conductive film 10 includes a support film 1, a conductive film 2 provided on the support film 1, and a photosensitive resin layer 3 provided on the conductive film 2. The conductive film 2 and the photosensitive resin layer 3 are collectively referred to as a photosensitive layer 4.
Hereinafter, each of the support film 1, the conductive film 2, and the photosensitive resin layer 3 constituting the photosensitive conductive film 10 will be described in detail.

<Support film>
Examples of the support film 1 constituting the photosensitive conductive film 10 of the present embodiment include polymer films having heat resistance and solvent resistance such as polyethylene terephthalate film, polyethylene film, polypropylene film, and polycarbonate film. Among these, a polyethylene terephthalate film is preferable from the viewpoint of transparency and heat resistance. These polymer films may be subjected to surface treatment within a range that can be removed from the photosensitive layer later.

  The haze value of the support film 1 is preferably 0.01 to 5.0%, more preferably 0.01 to 3.0%, from the viewpoint of improving sensitivity and resolution. More preferably, it is -2.0%, and it is especially preferable that it is 0.01-1.1%. In addition, a haze value can be measured based on JISK7105, for example, can be measured with commercial turbidimeters, such as brand name: NDH-5000 (made by Nippon Denshoku Industries Co., Ltd.).

<Conductive film>
The conductive film 2 constituting the photosensitive conductive film 10 of this embodiment is a film having conductivity, and preferably contains conductive fibers. Examples of the conductive fiber include metal fibers such as gold, silver and platinum, and carbon fibers such as carbon nanotubes. In this embodiment, it is preferable to use a metal fiber as the conductive fiber, and it is more preferable to use a silver fiber.

The metal fiber can be prepared by, for example, a method of reducing metal ions with a reducing agent such as NaBH ₄ or a polyol method. As the carbon nanotubes, commercially available products such as trade name: Hipco single-walled carbon nanotubes manufactured by Unidym Corporation can be used.

  The fiber diameter of the conductive fiber is preferably 1 to 50 nm, more preferably 2 to 20 nm, and further preferably 3 to 10 nm. The fiber length of the conductive fibers is preferably 1 to 100 μm, more preferably 2 to 50 μm, further preferably 3 to 40 μm, and particularly preferably 5 to 35 μm. The fiber diameter and fiber length can be measured with a scanning electron microscope.

  The thickness of the conductive film 2 varies depending on the use of the conductive pattern to be formed and the required conductivity, but is preferably 1 μm or less, more preferably 1 nm to 0.5 μm, and more preferably 5 nm to 0.1 μm. More preferably. When the thickness of the conductive film 2 is 1 μm or less, the light transmittance in the wavelength region of 450 to 650 nm is high, the pattern forming property is excellent, and it is particularly suitable for the production of a transparent electrode.

  The conductive film 2 preferably has a network structure in which conductive fibers are in contact with each other. The conductive film 2 having such a network structure may be formed on the surface of the photosensitive resin layer 3 on the side of the support film 1, but is electrically conductive in the surface direction on the surface exposed when the support film 1 is peeled off. If it is obtained, it may be formed in the form included in the surface layer on the support film 1 side of the photosensitive resin layer 3. Note that the thickness of the conductive film 2 having a network structure indicates a value measured by a scanning electron micrograph.

The conductive film 2 containing conductive fibers is coated on the support film 1 with a conductive fiber dispersion obtained by adding a dispersion stabilizer such as water or an organic solvent or a surfactant to the conductive fibers described above. It can be formed by drying. After drying, the conductive film 2 formed on the support film 1 may be laminated as necessary.
Coating can be performed by a known method such as a roll coating method, a comma coating method, a gravure coating method, an air knife coating method, a die coating method, a bar coating method, or a spray coating method, but the film thickness distribution is good. In view of the fact that there is little foreign matter mixed into the coating liquid in a closed system, the die coating method is preferred.

  From the viewpoint of reducing the resistance or haze of the conductive film 2, it is preferable to volatilize the solvent at a drying temperature of 20 ° C. or higher and 65 ° C. or lower in order to form a uniform film in the drying step. When the drying temperature is in the above range, particularly when the conductive fibers are silver fibers, it is possible to significantly reduce the resistance or haze. The drying temperature is preferably 65 ° C. or lower from the viewpoint of preventing convection from forming and forming a Benard cell and becoming difficult to form a low-resistance conductive film. Moreover, it is preferable that a drying temperature is 20 degreeC or more from a viewpoint which prevents a solvent from volatilizing and it takes time and becomes a problem on a process. The drying temperature is more preferably 25 ° C. or more and 65 ° C. or less, further preferably 35 ° C. or more and 65 ° C. or less, and particularly preferably 40 ° C. or more and 60 ° C. or less.

  In the conductive film 2, the conductive fiber may coexist with a surfactant or a dispersion stabilizer.

<Photosensitive resin layer>
The photosensitive resin layer 3 is formed from a photosensitive resin composition containing (a) a binder polymer, (b) a photopolymerizable compound, and (c) a photopolymerization initiator.

  As the (a) binder polymer, conventionally known binder polymers can be used without particular limitation, but acrylic resins are preferred. The acrylic resin can be produced, for example, by radical polymerization of (meth) acrylic acid or (meth) acrylic acid ester.

  As (meth) acrylic acid ester, (meth) acrylic acid alkyl ester, (meth) acrylic acid aryl ester, (meth) acrylic acid tetrahydrofurfuryl ester, (meth) acrylic acid dimethylaminoethyl ester, (meth) acrylic acid Examples include diethylaminoethyl ester, (meth) acrylic acid glycidyl ester, 2,2,2-trifluoroethyl (meth) acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate, and the like.

  Examples of the (meth) acrylic acid alkyl ester include methyl (meth) acrylate, ethyl (meth) acrylate, dicyclopentanyl (meth) acrylate, and the like. Examples of the (meth) acrylic acid aryl ester include benzyl (meth) acrylate. The acrylic resin may include a structural unit based on styrene.

  (A) It is preferable that a binder polymer has a carboxyl group from a viewpoint of making alkali developability more favorable. Examples of the polymerizable monomer having a carboxyl group for obtaining such a binder polymer include (meth) acrylic acid as described above.

  (A) The ratio of the carboxyl group of the binder polymer is 10 to 50% by mass as the ratio of the polymerizable monomer having a carboxyl group to the total polymerizable monomer used to obtain the binder polymer. It is preferably 12 to 40% by mass, more preferably 15 to 30% by mass, and particularly preferably 15 to 25% by mass. In terms of excellent alkali developability, it is preferably 10% by mass or more, and in terms of excellent alkali resistance, it is preferably 50% by mass or less.

The weight average molecular weight of the binder polymer as component (a) is preferably 10,000 to 200,000, more preferably 15,000 to 150,000, still more preferably 30000 to 150,000 from the viewpoint of resolution, and 30000. It is especially preferable that it is ˜100,000. If it is less than 10,000, the adhesiveness may be lowered because the alkali resistance of the cured film is low at the time of development, and if it exceeds 200,000, the developability of the unexposed part may be lowered at the time of development, and it may be difficult to obtain a good pattern. .
In addition, the weight average molecular weight in this specification is a value measured by a gel permeation chromatography method (GPC) and converted by a calibration curve created using standard polystyrene.

  As the photopolymerizable compound as component (b), a photopolymerizable compound having an ethylenically unsaturated group can be used. Thereby, the resolution of the conductive pattern 2a shown in FIGS. 4 to 6 to be described later and the adhesiveness with the substrate 20 (transparent base material) can be made more highly compatible.

  Examples of the photopolymerizable compound having an ethylenically unsaturated group include a monofunctional vinyl monomer, a bifunctional vinyl monomer, and a polyfunctional vinyl monomer having at least three polymerizable ethylenically unsaturated groups.

  Examples of the monofunctional vinyl monomer include (meth) acrylic acid, (meth) acrylic acid alkyl ester, monomers copolymerizable therewith, and the like.

  Bifunctional vinyl monomers include polyethylene glycol di (meth) acrylate, trimethylolpropane di (meth) acrylate, polypropylene glycol di (meth) acrylate, 2,2-bis (4- (meth) acryloxypolyethoxyphenyl) propane ), Bisphenol A diglycidyl ether di (meth) acrylate, and the like.

  Examples of the polyfunctional vinyl monomer having at least three polymerizable ethylenically unsaturated groups include trimethylolpropane tri (meth) acrylate, tetramethylolmethanetri (meth) acrylate, tetramethylolmethanetetra (meth) acrylate, and dipentaerythritol. Compounds obtained by reacting an α, β-unsaturated carboxylic acid with a polyhydric alcohol such as penta (meth) acrylate and dipentaerythritol hexa (meth) acrylate; glycidyl groups such as trimethylolpropane triglycidyl ether triacrylate And compounds obtained by adding an α, β-unsaturated carboxylic acid to the containing compound.

  The content of the component (a) is preferably 40 to 80 parts by mass, and more preferably 50 to 70 parts by mass with respect to 100 parts by mass of the total amount of the components (a) and (b). If this content is 40 parts by mass or more, the coating property is excellent, and a transfer-type photosensitive conductive film, which will be described later, is formed, and when wound into a roll, edge fusion (the resin oozes out from the film end). Can be prevented. If it is 80 mass parts or less, it will become a high sensitivity and the mechanical strength of a cured film can be improved.

  The content of the component (b) is preferably 20 to 60 parts by mass and more preferably 30 to 50 parts by mass with respect to 100 parts by mass of the total amount of the components (a) and (b). If this content is 20 parts by mass or more, the sensitivity becomes high and the mechanical strength can be increased. If it is 60 parts by mass or less, the coating property is excellent, and it is possible to prevent edge fusion from occurring when a transfer-type photosensitive conductive film described later is formed and wound into a roll.

  As the photopolymerization initiator which is component (c), conventionally known photopolymerization initiators can be used without any particular limitation. Specifically, aromatic ketone, oxime ester compound, phosphine oxide compound, benzyl derivative, 2,4,5-triarylimidazole dimer, acridine derivative, N-phenylglycine, N-phenylglycine derivative, coumarin compound And oxazole-based compounds.

  Among these, an oxime ester compound or a phosphine oxide compound is preferable because it is excellent in pattern forming ability when formed into a thin film (for example, a thickness of 10 μm or less) and easily forms a conductive pattern excellent in transparency.

  Examples of the oxime ester compound include 1- [4- (phenylthio) phenyl] -1,2-octanedione 2- (O-benzoyloxime)], 1- [9-ethyl-6- (2-methylbenzoyl) -9H. -Carbazol-3-yl] ethanone 1- (O-acetyloxime) and the like. Examples of the phosphine oxide compound include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide.

  The content of the component (c) is preferably 0.1 to 10 parts by mass, and preferably 0.2 to 5 parts by mass with respect to 100 parts by mass of the total amount of the components (A) and (B). More preferred is 1 to 5 parts by mass. If this content is 0.1 parts by mass or more, the sensitivity can be sufficiently increased. If it is 10 mass parts or less, it can prevent that absorption in the surface of a composition increases in the case of exposure, and internal photocuring becomes inadequate.

  In the present invention, the photosensitive layer 4 which is a laminate of the conductive film 2 and the photosensitive resin layer 3 has a wavelength region of 450 to 650 nm when the total thickness of the conductive film 2 and the photosensitive resin layer 3 is 1 to 30 μm. The light transmittance is preferably 80% or more, and more preferably 85% or more. When the photosensitive layer 4 satisfies such conditions, visibility can be improved over the entire surface of the substrate such as a display panel.

<Photosensitive silver paste>
The photosensitive silver paste used in the present invention has (A) a binder polymer, (B) a photopolymerizable compound, (C) a photopolymerization initiator, and (D) a silver powder as a basic composition. A conductive photosensitive resin composition containing glass frit and (F) an organic solvent. The photosensitive silver paste is produced by combining the components (A) to (E) with vacuum defoaming stirring and roll kneading.

  (A) As binder polymer, resin of the same system as said (a) binder polymer used in the case of forming the photosensitive resin layer which comprises the said photosensitive conductive film can be used. (A) It is preferable that a binder polymer has a carboxyl group from a viewpoint of making alkali developability more favorable. Examples of the polymerizable monomer having a carboxyl group for obtaining such a binder polymer include (meth) acrylic acid as described above.

  (A) The ratio of the carboxyl group that the binder polymer has is 10 to 50% by mass as the ratio of the polymerizable monomer having a carboxyl group to the total polymerizable monomer used to obtain the binder polymer. It is preferably 12 to 40% by mass, more preferably 15 to 30% by mass, and particularly preferably 15 to 25% by mass. In terms of excellent alkali developability, it is preferably 10% by mass or more, and in terms of excellent alkali resistance, it is preferably 50% by mass or less.

  As the photopolymerizable compound as component (B), a photopolymerizable compound having an ethylenically unsaturated group can be used. Examples of the photopolymerizable compound having an ethylenically unsaturated group include a monofunctional vinyl monomer, a bifunctional vinyl monomer, and a polyfunctional vinyl monomer having at least three polymerizable ethylenically unsaturated groups. As the monofunctional vinyl monomer, the bifunctional vinyl monomer, and the polyfunctional vinyl monomer, for example, (b) used as the binder polymer used when forming the photosensitive resin layer constituting the photosensitive conductive film, the above-mentioned examples are mentioned. Various vinyl monomers can be used.

  As the photopolymerization initiator which is the component (C), conventionally known photopolymerization initiators can be used without particular limitation. Specifically, aromatic ketone, oxime ester compound, phosphine oxide compound, benzyl derivative, 2,4,5-triarylimidazole dimer, acridine derivative, N-phenylglycine, N-phenylglycine derivative, coumarin compound And oxazole-based compounds.

  The content of each component of (A), (B) and (C) is the above (a), (b) and (c) used when forming the photosensitive resin layer constituting the photosensitive conductive film. The content of each component can be selected basically in the same range, but it is preferable to adjust the content of each component according to the viscosity and photocurability of the photosensitive silver paste.

  (D) Silver powder is used for imparting electrical conductivity. In the present invention, from the viewpoint of applicability or printability of the photosensitive silver paste, it may contain spherical silver powder to reduce the viscosity. preferable. (D) The compounding quantity of silver powder is 200-1000 from the point of electroconductivity, light transmittance, and a viscosity, when the total amount of each component of said (A), (B) and (C) is 100 mass parts. It is preferable that it is a mass part. (D) When the silver powder is less than 200 parts by mass, sufficient conductivity cannot be obtained. When the silver powder exceeds 1000 parts by mass, not only the curability of the photosensitive silver paste is greatly reduced due to the deterioration of light transmittance but also the viscosity is low. It is too high, and the applicability or printability is significantly reduced.

  (E) The glass frit is used to sinter silver after firing when the photosensitive silver paste is fired at a high temperature. When the photosensitive silver paste is thermally cured by heat treatment at 200 ° C. or lower after light irradiation, (E) a photosensitive resin paste not containing glass frit is usually used.

  (F) The organic solvent is used when the photosensitive silver paste is made to have a desired viscosity to improve the coating workability by dispenser or screen printing. If this is not necessary, (F) a photosensitive silver paste containing no organic solvent may be used. (F) As an organic solvent, a well-known organic solvent can be used, for example, alcohol solvent, ketone solvent, cellosolve solvent, ester solvent, ether solvent, lactone solvent, aromatic hydrocarbon type. Examples include solvents and aliphatic hydrocarbon solvents.

  Further, the photosensitive bottle paste used in the present invention includes, in addition to the above components, a sensitizer, a polymerization inhibitor, a dispersant, an antifoaming agent, a thickener, a suspending agent, a leveling agent, and the like. Can be added as needed.

<Method for forming conductive pattern>
As described above, the photosensitive conductive film 10 used in the present invention can be applied when a conductive pattern is formed on a substrate. Therefore, an example of a method for forming a conductive pattern using the photosensitive resin film 10 will be described with reference to FIGS. Here, the steps shown in FIGS. 4 to 6 can also be employed for forming the conductive pattern of the connection wiring 105 drawn from the electrode of the conductive pattern in the present invention. Among these processes, the wiring for connection with the electrode according to the present invention is conductive by the method shown in FIGS. 4 and 5 which is excellent in workability from the viewpoint of coating of the photosensitive silver paste or coating property of the photosensitive conductive film. It is preferable to form a pattern.

The conductive pattern is formed by irradiating the photosensitive resin layer 3 and the conductive film 2 provided on the substrate (support film 1) with actinic rays in a pattern using the photosensitive conductive film 10 shown in FIG. An exposure step and a development step of forming a conductive pattern by removing the unexposed portions of the photosensitive resin layer 3 and the conductive film 2.
As described above, the photosensitive resin layer 3 contains a binder polymer, a photopolymerizable compound, and a photopolymerizable initiator.
The conductive film (conductive layer) 2 is a film provided on the surface of the photosensitive resin layer 3 opposite to the substrate 20 (surface on the support film 1 side), and enables bonding at the connection point of the conductive fibers. Containing compounds.

An embodiment of the method for forming a conductive pattern of the present invention will be described with reference to FIG.
For the formation of the conductive pattern, the laminate shown in FIG. 4A can be used. In the laminate of FIG. 4A, a photosensitive conductive layer 10 including a photosensitive resin layer 3 and a conductive film 2 and a support film 1 is provided on a substrate 20.
In addition, this laminated body can be obtained by laminating | stacking the photosensitive conductive film 10 of this invention mentioned above on the board | substrate 20 so that the photosensitive resin layer 3 may contact | connect the board | substrate 20, for example.

  First, the mask 5 is provided on the photosensitive conductive film 10, and the photosensitive layer 4 (the conductive film 2 and the photosensitive resin layer 3) is irradiated with the active light L in a pattern through the mask 5 (exposure process: FIG. 4). (B)). Next, a conductive pattern (conductive film 2a) is formed by removing an uncured portion (unexposed portion) by development (development process: FIG. 4C).

  Here, the conductive pattern obtained by the above method has the thickness of the cured resin layer 3b in addition to the thickness of the conductive film 2a. These thicknesses are steps Hb from the substrate. If the level difference Hb is large, the smoothness required for a display or the like may be difficult to obtain, and the conductive pattern may be easily visually recognized. it can.

Another embodiment of the method for forming a conductive pattern of the present invention will be described with reference to FIG.
The method shown in FIG. 5 is the same as the above manufacturing method up to the exposure step (first exposure step: FIG. 5B) in which a predetermined portion of the photosensitive layer 4 having the support film 1 is irradiated with actinic rays.
After the first exposure step, the support film 1 is peeled off, and in the presence of oxygen, a part or all of the exposed and unexposed portions in the first exposure step are irradiated with actinic rays (second Exposure process: FIG. 5C). As a result, the resin cured layer 3a in which the conductive film 2a is not formed together with the conductive pattern 2a is provided on the substrate 20, so that the conductive property is reduced as compared with the case of FIG. 3C in which only the conductive pattern is provided on the substrate. The step of the pattern can be reduced (step Ha shown in FIG. 5D).

  As described above, the conductive pattern is preferably formed using the photosensitive conductive film used in the present invention. However, the method is not limited to this. For example, as shown in FIG. You may form by exposing and developing after forming the resin layer and the electrically conductive film containing a conductive fiber separately. With reference to FIG. 6, still another embodiment of a method for forming a conductive pattern on a substrate will be described.

For the formation of the conductive pattern, the laminate shown in FIG. 6A can be used. In the laminated body of FIG. 6A, a photosensitive layer 4 including a photosensitive resin layer 3 and a conductive film 2 is provided on a substrate 20. Here, the photosensitive resin layer 3 contains a binder polymer, a photopolymerizable compound, and a photopolymerizable initiator. The conductive film (conductive layer) 2 is a film provided on the surface of the photosensitive resin layer 3 opposite to the substrate 20, that is, on the photosensitive resin layer 3, and is bonded at the connection point of the conductive fibers. Including compounds that enable
For example, after applying the photosensitive resin layer 3 on the substrate 20 and drying the laminate, the dispersion containing conductive fibers is uniformly applied on the photosensitive resin layer 3 and dried by heating. And can be formed by pressurizing at room temperature or under heating.

  In the exposure, a mask 5 is provided slightly apart from the photosensitive layer 4 so as not to contact the conductive film 2 located above the photosensitive layer 4, and the photosensitive layer 4 (the conductive film 2 and the photosensitive resin layer is interposed through the mask 5). 3) is performed by irradiating active light L in a pattern (exposure process: FIG. 6B). If necessary, a thin transparent film is laminated on the conductive film 2, a mask is provided on the transparent film, and exposure is performed through the mask. Then, the transparent film is removed from the conductive film 2. You may employ | adopt the method to peel. Next, a conductive pattern (conductive film 2a) is formed by removing uncured portions (unexposed portions) by development (development process: FIG. 6C).

  Here, the conductive pattern obtained by the above method has the thickness of the cured resin layer 3b in addition to the thickness of the conductive film 2a. These thicknesses are steps Hb from the substrate. If the level difference Hb is large, the smoothness required for a display or the like may not be obtained, and the conductive pattern may be easily visible. In that case, in the method shown in FIG. 5, a conductive pattern is formed by forming a laminate having the photosensitive layer 4 shown in FIG. 6A instead of the photosensitive conductive film 10. Here, the photosensitive layer 4 is produced by separately forming the photosensitive resin layer 3 and the conductive film 2 on the substrate 20. Thereafter, a conductive pattern is formed by performing exposure and development twice in the same manner as in the steps shown in FIGS. In the conductive pattern formed in this way, the step of the conductive pattern can be made smaller than in the case of FIG.

<Touch panel sensor>
FIG. 7 is a schematic diagram showing an example of a method for manufacturing the touch panel sensor shown in FIG. In the present embodiment, the transparent electrodes 103 and 104 are formed by the conductive pattern forming method according to the present invention. First, as shown in FIG. 7A, a transparent electrode (X position coordinate) 103 is formed on a transparent substrate 101. Specifically, the photosensitive conductive film 10 is laminated so that the photosensitive resin layer is in contact with the transparent substrate 101. The transferred photosensitive layer 4 (the conductive film 2 and the photosensitive resin layer 3) is irradiated with an actinic ray in a desired shape through a light-shielding mask (first exposure step). Thereafter, the light shielding mask is removed, the support film is further peeled off, and the photosensitive layer 4 is irradiated with actinic rays (second exposure step). By performing development after the exposure step, the conductive film 2 is removed together with the photosensitive resin layer 3 that is not sufficiently cured, and a conductive pattern 2a is formed. The transparent electrode 103 for detecting the X position coordinate is formed by the conductive pattern 2a (FIG. 7B). FIG.7 (b) is a schematic cross section of the II cut surface of Fig.7 (a). By forming the transparent electrode 103 by the method for forming a conductive pattern according to the present invention, the transparent electrode 103 with a small step can be provided.

  Subsequently, a transparent electrode (Y position coordinate) 104 is formed as shown in FIG. A new photosensitive conductive film 10 is further laminated on the substrate 101 including the transparent electrode 103 formed by the above-described process, and the transparent electrode 104 for detecting the Y position coordinate is formed by the same operation as described above (see FIG. 7 (d)). FIG.7 (d) is a schematic cross section of the II-II cut surface of FIG.7 (c). By forming the transparent electrode 104 by the conductive pattern forming method according to the present invention, even when the transparent electrode 104 is formed on the transparent electrode 103, reduction in aesthetics due to stepping or entrainment of bubbles is sufficiently suppressed. A touch panel sensor with high smoothness can be created.

  Next, as shown in FIG. 1, on the surface of the transparent substrate 101, a lead-out wiring 105 for connecting to the external circuit according to the present invention and a connection electrode 106 for connecting the lead-out wiring 105 and the transparent electrodes 103, 104 are provided. Form. In FIG. 7, the lead-out wiring 105 and the connection electrode 106 are shown to be formed after the formation of the transparent electrodes 103 and 104, but they may be formed at the same time as the formation of each transparent electrode. The lead-out wiring 105 is formed by a method of applying the photosensitive silver paste by a dispenser application method or a screen printing method, or a method of irradiating actinic rays such as ultraviolet rays using the photosensitive conductive film. In the present invention, the lead-out wiring 105 serving as a connection wiring with the electrode can be formed at the same time as the connection electrode 106 is formed. Furthermore, when forming each transparent electrode on the substrate with the photosensitive conductive film, the lead-out wiring 105 and the connection electrode 106 may be formed simultaneously using the same photosensitive conductive film.

8 and 9 are partial cross-sectional views taken along the lines aa ′ and bb ′ shown in FIG. 1, respectively. These indicate the intersections of the transparent electrodes at the XY position coordinates.
As shown in FIGS. 8 and 9, the transparent electrode is formed by the conductive pattern forming method, so that a touch panel sensor with small steps and high smoothness can be obtained.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to this.

(Examples 1 to 3, Comparative Example 1)
[Preparation of silver fiber dispersion]
(1) Preparation of silver fiber by polyol method 500 ml of ethylene glycol was placed in a 2000 ml three-necked flask and heated to 160 ° C. with an oil bath while stirring with a magnetic stirrer in a nitrogen atmosphere. A solution prepared by dissolving ₂ mg of PtCl ₂ separately prepared in 50 ml of ethylene glycol was added dropwise thereto. After 4 to 5 minutes, a solution in which 5 g of AgNO ₃ was dissolved in 300 ml of ethylene glycol and a solution in which 5 g of polyvinylpyrrolidone having a weight average molecular weight of 40,000 (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 150 ml of ethylene glycol were respectively obtained. From the dropping funnel in 1 minute, and then stirred at 160 ° C. for 60 minutes.

The reaction solution was allowed to stand at 30 ° C. or lower, diluted 10-fold with acetone, centrifuged at 2000 min ⁻¹ for 20 minutes with a centrifuge, and the supernatant was decanted. Acetone was added to the precipitate, and after stirring, the mixture was centrifuged under the same conditions as described above, and acetone was decanted. Then, it centrifuged twice similarly using distilled water, and obtained the silver fiber. When the obtained silver fiber was observed with a scanning electron microscope, the fiber diameter (diameter) was 30 nm, and the fiber length was 30 μm. The fiber diameter and fiber length of the silver fibers are calculated based on measurement results of fiber diameters and fiber lengths of 100 silver fibers selected at random from the scanning electron microscope observation region. Average value (arithmetic average value).

(2) Preparation of silver fiber dispersion liquid In pure water, the silver fiber obtained in the above (1) is dispersed at a concentration of 0.2% by mass and dodecyl-pentaethylene glycol at a concentration of 0.1% by mass. Thus, a silver fiber dispersion was obtained.

[Preparation of photosensitive resin composition solution]
It mix | blended with the following compounding quantity (unit: mass part), and prepared the solution of the photosensitive resin composition.
(A) Acrylic polymer A
(B) Ditrimethylolpropane tetraacrylate (T-1420, manufactured by Nippon Kayaku Co., Ltd.)
(C) 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (IRGACURE TPO, manufactured by BASF)
(D) Methyl ethyl ketone = (a) 65 / (b) 35 / (c) 10 / (d) 150

<Preparation of photosensitive conductive film>
The above-mentioned silver fiber dispersion was uniformly applied at 26 g / m ² onto a 16 μm thick polyethylene terephthalate film (PET film, manufactured by Toyobo Co., Ltd., trade name: A1517) as the support film 1, and hot air convection at 100 ° C. The conductive film 2 containing silver fibers was formed on the support film 1 by drying for 10 minutes with a rotary dryer and pressurizing at a linear pressure of 1 MPa at room temperature (25 ° C.) (on the support film 1 shown in FIG. 2) Conductive film 2). In addition, when measured by a scanning electron micrograph, the film thickness after drying of the conductive film 2 was about 0.1 μm.

  Next, the photosensitive resin composition solution is uniformly applied on the conductive film 2 formed on the support film 1 and dried for 10 minutes in a hot air convection dryer at 100 ° C. to form the photosensitive resin layer 3. It was formed (photosensitive resin layer 3 on the conductive film 2 shown in FIG. 2). In addition, when measured with the scanning electron micrograph, the film thickness after drying of the photosensitive resin layer 3 was 5 μm. The photosensitive resin layer 3 was formed by drying for 10 minutes with a 100 ° C. hot air convection dryer. In addition, when measured with the scanning electron micrograph, the film thickness after drying of the photosensitive resin layer 3 was 5 μm. Next, the photosensitive resin layer 3 was covered with a 30 μm-thick biaxially stretched polypropylene cover film (not shown) (trade name: ES201, manufactured by Oji F-Tech Co., Ltd.) to obtain a photosensitive conductive film 10.

  Photosensitive conductive films A to C having a Cl ion content of 500 ppm or less by adjusting the photosensitive conductive film 10 using a component whose Cl ion content has been reduced by washing with an ion exchange resin or the like. (Examples 1-3) were prepared. In addition, a photosensitive conductive film D (Comparative Example 1) not particularly subjected to a treatment for reducing Cl ions was prepared. The Cl ion content of each photosensitive conductive film is 18 ppm for photosensitive conductive film A (Example 1), 220 ppm for B (Example 2), 380 ppm for C (Example 3), and D (Comparative Example 1). Is 1200 ppm.

<Formation of conductive pattern used for connection wiring>
As shown in FIG. 4 (a), on the surface of the substrate 20, a 125 μm thick PET film (manufactured by Toyobo Co., Ltd., trade name: Cosmo Shine-A300 (“Cosmo Shine” is a registered trademark)) While removing the protective film (not shown) of the photosensitive conductive film 10 (photosensitive conductive films A to C: Examples 1 to 3 and D: Comparative Example 1) obtained above, the photosensitive resin layer 3 was removed. It was made to oppose a PET film (board | substrate 20), and it laminated on the conditions of 110 degreeC, 0.6 m / min, and 0.4 MPa.

As shown in FIG. 4 (b), after lamination, the PET film (substrate 20) is cooled, and when the temperature reaches 23 ° C., the mask 5 (L / S = 1 mm / 1 mm, L: width of the conductor pattern) , S: gap between conductor patterns), and using an exposure machine (trade name: EXM-1201, manufactured by Oak Manufacturing Co., Ltd.) having a high-pressure mercury lamp lamp from the support film 1 side, with an exposure amount of 60 mJ / cm ^2. Irradiated with light. After the light irradiation, the support film 1 was peeled off and irradiated with light at an exposure amount of 100 mJ / cm ² (L in FIG. 4B represents irradiation light). Next, development was carried out by spraying a 1% by mass aqueous sodium carbonate solution at 30 ° C. for 40 seconds to obtain a conductor pattern 2a shown in FIG. Further, an exposure dose of 1 J / cm ² was irradiated with a UV exposure machine. Through the above operation, a sample having a linear conductive pattern having a width of 1 mm as shown in FIG.

(Example 4, Comparative Example 2)
<Preparation of photosensitive silver paste>
In Example 4, a photosensitive silver paste having a Cl ion content of 500 ppm or less was prepared by adjusting a photosensitive silver paste using a component whose Cl ion content was reduced by washing with an ion exchange resin or the like. Paste A was used. The Cl ion content of the photosensitive silver paste A actually used is 400 ppm. On the other hand, in the comparative example 4, the photosensitive silver paste B adjusted using the component which has not performed the process which reduces Cl ion was used. The Cl ion content of the photosensitive silver paste B actually used is 1400 ppm.
<Formation of conductive pattern used for connection wiring>
A photosensitive silver paste A (Example 4) is formed on the surface of a PET film (product name: Cosmo Shine-A300 (“Cosmo Shine” is a registered trademark)) having a thickness of 125 μm, which is a substrate 20. And B (Comparative Example 2) were applied by a clean printing method. The conductor pattern at this time is a linear conductive pattern having a width of 1 mm as shown in FIG. 10 as in Examples 1 to 3 and Comparative Example 1. Next, as a pretreatment, after drying at 110 ° C. for 10 minutes, light irradiation was performed at an exposure amount of 300 mJ / cm ² . Thereafter, as the main drying, main drying was performed at 140 ° C. for 30 minutes to prepare a sample having a pattern of a photosensitive silver paste used for connection wiring.

<Preparation of sample for connection stability evaluation>
The samples prepared in Examples 1 to 4 and Comparative Examples 1 and 2 were exposed up to 10 mm from both ends of the linear conductive pattern having a width of 1 mm, and the entire area inside was covered so as to cover the entire area. (Clear Adhesive) was pasted and then allowed to stand at 50 ° C., 0.5 MPa for 30 minutes in an autoclave tester. In the linear conductive pattern having a 1 mm width of the sample, the region exposed from the OCA and extending from the both ends to 10 mm is a terminal for measuring a resistance value in the connection stability evaluation described later.

<Connection stability evaluation method>
After leaving the samples prepared in Examples 1 to 4 and Comparative Examples 1 and 2 under 85 ° C. and 85% reliability conditions, using a tester (product name: MCD-008) manufactured by Multi Measurement Instruments) A resistance value between terminals provided at both ends of a linear conductive pattern having a width was measured, and an increase rate was calculated. The measurement results of Examples 1 to 4 and Comparative Examples 1 and 2 are shown in Table 1 below.

<Photosensitive silver paste, Cl ion content analysis method of photosensitive conductive film>
The amount of Cl ions contained in the photosensitive silver paste or the photosensitive layer of the photosensitive conductive film was detected using combustion ion chromatography (trade name: ICS-1600, manufactured by Nippon Dionex Co., Ltd.).

＊：抵抗値上昇率(初期値比較) … ○：≦20％、×：＞20％

*: Resistance value increase rate (initial value comparison)… ○: ≦ 20%, ×:> 20%

(Examples 1-4)
When the photosensitive conductive films A to C or the photosensitive silver paste A having a small Cl ion detection amount were used for the connection wiring, the target value of 1000 hours could be exceeded.
(Comparative Examples 1 and 2)
When the photosensitive conductive film D or the photosensitive silver paste B having a large amount of detected Cl ions was used for the connection wiring, the connection reliability increased by 20% or more from the initial value in 400 hours or 200 hours.

  As described above, the Cl ion mixed in the photosensitive layer or photosensitive silver paste of the photosensitive conductive film is measured, and the reliability is improved by using the photosensitive conductive film or the photosensitive silver paste having a small amount of Cl ion detection. Connectivity can be greatly improved under test conditions. In addition, when a material that easily contains Cl ions is used in the production of the photosensitive conductive film or photosensitive silver paste, the amount of Cl ions mixed can be reduced by a process such as cleaning. Further, since the photoinitiator may generate Cl ions during the reaction, it is not limited to the photoinitiator, and it is preferable to use a material that does not easily generate Cl ions in the reaction process.

  The photosensitive conductive film, the conductive pattern, and the photosensitive silver paste of the present invention can be used for forming a conductive pattern used as an electrode wiring of a device such as a flat panel display such as a liquid crystal display element, a touch screen, or a solar cell. . The touch panel sensor of the present invention can be used for a liquid crystal display element or a touch screen.

1 support film 2 conductive film or conductive layer 2a conductive pattern (conductive film)
DESCRIPTION OF SYMBOLS 3 Photosensitive resin layer 3a, 3b Resin hardening layer 4 Photosensitive layer 5 Mask 10 Photosensitive conductive film 20 Substrate 101 Transparent substrate 102 Touch screen 103 Transparent electrode (X position coordinate)
104 Transparent electrode (Y position coordinate)
105 Lead-out wiring or connection wiring 106 Connection electrode 107 External connection terminal L Irradiation light

Claims (9)

  In order to make an electrical connection between the electrode on the substrate and the external connection terminal, the connection wiring is formed by drawing out from the electrode, and the connection wiring is formed by a photosensitive silver paste or a photosensitive conductive film. Wiring for connection whose content of Cl ion contained in the photosensitive layer of the photosensitive silver paste or the photosensitive conductive film is 500 ppm or less.   The photosensitive conductive film is a photosensitive conductive film having the support film, a conductive layer provided on the support film, and a photosensitive layer including a photosensitive resin layer provided on the conductive film, The connection wiring according to claim 1, wherein the photosensitive resin layer contains (a) a binder polymer, (b) a photopolymerizable compound, and (c) a photopolymerization initiator.   The connection according to claim 1, wherein the photosensitive layer has a light transmittance of 80% or more in a wavelength region of 450 to 650 nm when the total thickness of the conductive film and the photosensitive resin layer is 1 to 30 μm. Wiring.   The connection wiring according to claim 2, wherein the conductive film contains conductive fibers.   The connection wiring according to claim 4, wherein the conductive fiber is silver fiber. A method for forming the connection wiring according to any one of claims 1 to 5,
A method for forming a connection wiring, comprising a step of applying the photosensitive silver paste by a dispenser coating method or a screen printing method. A method for forming the connection wiring according to any one of claims 1 to 5,
Laminating the photosensitive conductive film so as to adhere to the substrate;
An exposure step of irradiating a predetermined portion of the photosensitive layer of the photosensitive conductive film on the substrate with an actinic ray;
A developing step of forming a conductive pattern of the connection wiring by developing an unexposed portion of the photosensitive layer after exposure;
A method for forming connection wiring. A method for forming the connection wiring according to any one of claims 1 to 5,
Laminating the photosensitive conductive film so that the photosensitive resin layer is in close contact with the substrate;
An exposure step of irradiating a predetermined portion of the photosensitive resin layer on the substrate with an actinic ray;
A development step of forming a conductive pattern of the connection wiring by developing the exposed photosensitive resin layer and an unexposed portion of the conductive film after peeling the support film;
A method for forming connection wiring. A method for forming a wiring pattern of a wiring for connection with an electrode according to any one of claims 1 to 5,
Laminating the photosensitive conductive film so that the photosensitive resin layer is in close contact with the substrate;
A first exposure step of irradiating a predetermined portion of the photosensitive resin layer on the substrate with an actinic ray;
After peeling the support film, in the presence of oxygen, a second exposure step of irradiating a part or all of the unexposed portion in the first exposure step with actinic rays,
After the second exposure step, a developing step of forming the conductive pattern of the connection wiring by developing the photosensitive resin layer and the conductive film;
A method for forming connection wiring.

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