JP2017182708A - Anisotropic conductive connection structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new and improved anisotropic conductive connection structure which enables direct anisotropic conductive connection of a first electrode terminal including partition walls and a conductive layer and a second electrode terminal.SOLUTION: An anisotropic conductive connection structure includes: a substrate 15; a first electrode terminal 30 formed on the substrate 15; an electronic component 50 including a second electrode terminal 52; and an anisotropic conductive adhesive layer 40 including conductive particles 42 which conduct the first electrode terminal 30 and the second electrode terminal 52. The first electrode terminal 30 includes a plurality of partition walls 61 arranged on the substrate 15, and a conductive layer 63 arranged between the partition walls 61.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an anisotropic conductive connection structure.

  For example, as disclosed in Patent Documents 1 and 2, a touch panel is widely used as an input device that performs an input operation on an image displayed on a display. The touch panel is divided into an input operation area where an input operation by the user is performed and a peripheral area of the input operation area. An electrode group in which a plurality of electrodes are wired in a predetermined wiring pattern is arranged in the input operation area. Then, a plurality of electrode terminals are drawn from the electrode group. The electrode terminal is disposed in the peripheral region. Furthermore, the electrode terminal is connected to the terminal of the electronic component. Specifically, the electrode terminal and the terminal of the electronic component are anisotropically conductively connected by sandwiching conductive particles contained in the anisotropic conductive adhesive.

  In such a touch panel, when a user touches any position on the touch panel, an electrical change (for example, a change in capacitance) occurs in the electrode group at that position. Then, position information regarding the position where the electrical change has occurred is input to the electronic circuit via the electrode group and the electrode terminal. The electronic circuit recognizes the position touched by the user based on the input position information.

JP 2006-344163 A JP 2012-203696 A

  By the way, since the input operation area is an area visually recognized by the user, the electrode group is required to be transparent. ITO is known as an electrode material having such transparency. However, ITO has a problem that its resistance value is very high. For this reason, ITO has often been applied to small touch panels that are relatively insensitive to the high resistance value.

  As a technique for solving the above problem, a technique is proposed in which an electrode group includes a plurality of partition walls and a conductive layer disposed between the partition walls. In this technique, for example, a plurality of partition walls are arranged apart from each other in a lattice shape, and a conductive layer is disposed between the partition walls. In this case, the conductive layer is arranged in a mesh shape. The conductive layer is, for example, a layer in which metal particles are deposited. Since the electrode group formed by this technique has a low resistance value and low visibility (that is, it is difficult to see), it can be applied to a large touch panel. For this reason, the technique which comprises an electrode group with a some partition and a conductive layer attracts much attention.

  By the way, since the electrode terminal of a touch panel is arrange | positioned in the peripheral region which is hard to be visually recognized by the user, transparency is not necessarily requested | required. However, from the viewpoint of manufacturing cost and the like, in recent years, the number of cases in which the electrode group and the electrode terminal are made of the same electrode material is increasing. Therefore, when the electrode group is composed of partition walls and conductive layers, the electrode terminal is also composed of a plurality of partition walls and conductive layers.

  When the electrode terminal is composed of a plurality of partition walls and a conductive layer, many irregularities are formed on the surface of the electrode terminal by the partition walls and the conductive layer. That is, the surface shape of the electrode terminal is very complicated. For this reason, there has been a problem that the connection resistance becomes extremely large when anisotropic conductive connection is performed by directly arranging an anisotropic conductive adhesive on the electrode terminal including the partition and the conductive layer. This may be because the contact area between the conductive particles and the conductive layer is not sufficient. For this reason, when the electrode terminal including the partition wall and the conductive layer is directly anisotropically conductively connected to the electrode terminal of the electronic component, a product that can withstand practical use cannot be manufactured. That is, the electrode terminal including the partition wall and the conductive layer and the electrode terminal of the electronic component cannot be directly anisotropically conductively connected.

  For this reason, conventionally, after a metal film or a metal paste is laminated on the electrode terminal, the electrode terminal and the terminal of the electrode component are anisotropically conductively connected. However, this method has a problem that the cost for anisotropic conductive connection becomes extremely high.

  In addition, when an electrode terminal is comprised with ITO, the contact area of ITO and electroconductive particle can be enlarged enough. However, as described above, ITO has a problem that its resistance value is very high. Therefore, even if the electrode terminal is made of ITO, the above problem cannot be fundamentally solved.

  In addition, electrode terminals including partition walls and conductive layers are expected to be used for various purposes other than touch panels in the future. Therefore, there has been a strong demand for a technique for stably anisotropically connecting such electrode terminals and other electrode terminals at low cost.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to directly conduct anisotropic conduction between the first electrode terminal including the partition wall and the conductive layer and the second electrode terminal. It is an object of the present invention to provide a new and improved anisotropic conductive connection structure that can be connected.

  In order to solve the above problems, according to an aspect of the present invention, a substrate, a first electrode terminal formed on the substrate, an electronic component including a second electrode terminal, a first electrode terminal, An anisotropic conductive adhesive layer including conductive particles that conduct to the second electrode terminal, wherein the first electrode terminal is disposed between the plurality of partition walls disposed on the substrate and the partition walls. An anisotropic conductive connection structure comprising a conductive layer is provided.

  Here, the height of the partition may be 10 μm or less.

The distance from the surface of the conductive layer to the top of the partition and the particle size of the conductive particles before anisotropic conductive connection may satisfy the condition of the following mathematical formula (1).
(1/2) * D ≦ H ≦ (3/4) * D (1)
In Equation (1), H is the distance from the surface of the conductive layer to the top of the partition, and D is the particle size of the conductive particles before anisotropic conductive connection.

Moreover, the width | variety of a conductive layer and the particle size before anisotropic conductive connection of electroconductive particle may satisfy | fill the conditions of following Numerical formula (2).
W ≦ D ≦ 3 * W (2)
In Equation (2), W is the width of the conductive layer, and D is the particle size of the conductive particles before anisotropic conductive connection.

  Moreover, electroconductive particle may be provided with the core particle containing resin, and the conductive layer which coat | covers the surface of a core particle.

  According to the other viewpoint of this invention, a touch panel provided with said anisotropic conductive connection structure is provided.

  According to the other viewpoint of this invention, an image display apparatus provided with said touch panel is provided.

  As described above, according to the present invention, the first electrode terminal including the partition wall and the conductive layer and the second electrode terminal can be directly anisotropically conductively connected.

It is a top view which shows an example of the electrode group and electrode terminal which concern on embodiment of this invention. It is a top view which expands and shows the surface shape of an electrode group and a 1st electrode terminal. It is sectional drawing which expands and shows the cross-sectional shape of an electrode group and a 1st electrode terminal. It is a sectional side view which shows the structural example of an anisotropic conductive connection structure.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

<1. Overview of electrode group and electrode terminal>
In the present embodiment, the first electrode terminal 30 shown in FIG. 1 and a second electrode terminal 52 described later are anisotropically conductively connected. Here, the first electrode terminal 30 and the second electrode terminal 52 are part of the components of the touch panel. That is, this embodiment is applied to a touch panel. The touch panel is provided on the display surface of various displays (image display devices), for example. Therefore, first, the first electrode terminal 30 and its peripheral structure will be described with reference to FIGS. As shown in FIGS. 1 to 3, in the present embodiment, the electrode group 20 and the first electrode terminal 30 are wired on the substrate 15. The board 15 is divided into an input operation area A in which an input operation is performed by a user and a peripheral area B of the input operation area A. The electrode group 20 is disposed in the input operation area A, and the first electrode terminal 30 is disposed in the peripheral area B. The electrode group 20 includes a plurality of electrodes 20a wired in a predetermined wiring pattern. Then, a plurality of first electrode terminals 30 are drawn from the electrode group 20. The width W1 of the first electrode terminal 30 is larger than the width of the electrode 20a. The first electrode terminals 30 extend in directions parallel to each other. The width W1 and the inter-terminal space P of the first electrode terminal 30 may be appropriately set according to characteristics required for the touch panel. In the present embodiment, the first electrode terminal 30 and the second electrode terminal 52 of the electronic component 50 described later are anisotropically conductively connected. Of course, the wiring pattern of the electrode group 20 and the first electrode terminal 30 is not limited to the example of FIG.

  The substrate 15 is made of a material having transparency. Here, the material which comprises the board | substrate 15 will not be restrict | limited especially if it has transparency. For example, the board | substrate 15 may be comprised with the material used as a board | substrate of a touchscreen. Examples of the material constituting the substrate 15 include transparent resins such as polycarbonate, acrylic, polyethylene terephthalate, and triacetyl cellulose. The substrate 15 may be made of transparent glass or the like.

  The substrate 15 may be provided with an optical adhesive layer such as OCA (Optically Clear Adhesive) or a layer made of OCR (Optically Clear Resin). In the case where such a layer is provided, if the pressure is excessively increased, a defect in appearance tends to occur. Therefore, the thickness of such a layer is preferably 100 μm or less as an example.

  An uneven layer 60 is laminated on the substrate 15. Then, the electrode group 20 and the first electrode terminal 30 are formed on the uneven layer 60. The electrode group 20 and the first electrode terminal 30 include a plurality of partition walls 61 and a conductive layer 63 disposed between the partition walls 61. That is, in this embodiment, the electrode group 20 and the first electrode terminal 30 have the same structure.

  More specifically, a plurality of partition walls 61 are arranged in a lattice pattern in a region where the electrode group 20 and the first electrode terminal 30 are formed on the surface of the uneven layer 60. The conductive layer 63 is formed by filling the recess 62 formed between the plurality of partition walls 61 with a conductive material. Therefore, the conductive layer 63 is arranged on the uneven layer 60 in a mesh shape. Of course, the planar shape and arrangement pattern of the partition wall 61 and the conductive layer 63 are not limited to this example. That is, in the example of FIG. 1, the planar shape of the partition wall 61 is substantially square, but may be other types of polygons or random shapes. In the example shown in FIG. 1, the arrangement pattern of the partition walls 61 is a square lattice pattern, but may be another type of polygonal lattice pattern or a random arrangement pattern. The planar shape and arrangement pattern of the conductive layer 63 are determined by the planar shape and arrangement pattern of the partition walls 61. It is preferable that this arrangement pattern is hardly visible.

  The material which comprises the uneven | corrugated layer 60 will not be restrict | limited especially if it is a material which has transparency. The material constituting the concavo-convex layer 60 may be transparent, for example, among curable resins constituting the anisotropic conductive adhesive described later. Other examples include optical adhesives and liquid optical adhesives. Moreover, the manufacturing method of the uneven | corrugated layer 60 is not specifically limited, For example, you may produce by the well-known printing method. In this case, a master having an inverted shape of the surface shape of the uneven layer 60 is prepared. Then, an uncured curable resin is applied on the substrate 15. Next, the uneven structure of the master is transferred to the uncured curable resin layer by pressing the master against the uncured curable resin layer. Next, the uncured curable resin is cured.

The conductive layer 63 is made of a conductive material. Here, examples of the conductive material include metal particles. When the conductive material is metal particles, the conductive layer 63 is a deposited layer of metal particles. The metal particles are, for example, nanoscale particles. The specific particle diameter may be appropriately adjusted according to the characteristics required for the electrode group 20 and the first electrode terminal 30. As a metal which comprises a metal particle, gold | metal | money, silver, copper, aluminum, zinc, these 2 or more types of alloys, etc. are mentioned, for example. A metal particle may be comprised by 1 type of metal particles among these, and 2 or more types of mixtures may be sufficient as it. Among the above, silver particles are particularly preferable because of low cost and excellent conductivity. The density of the metal particles is not particularly limited, and may be appropriately set according to characteristics required for the electrode group 20 and the first electrode terminal 30. As an example, the density of the metal particles is preferably 0.5 to 2.0 g / m ² . The lower limit is more preferably 0.7 g / m ² or more, and the upper limit is more preferably 1.8 g / m ² or less. Here, the density of the metal particles is a so-called surface density with respect to the area of the substrate surface on which the uneven layer 60 is formed. In this case, the visibility of the conductive layer 63 can be reduced, and the resistance value of the conductive layer 63 (more specifically, the connection resistance of the anisotropic conductive connection structure 10) can be reduced. .

  The height h of the partition wall 61 is not particularly limited, but the upper limit value is preferably 10 μm or less, more preferably 8 μm or less, and 6 μm or less in order to reduce the visibility of the conductive layer 63. Even more preferred. The lower limit value of the height h of the partition wall 61 is not particularly limited, but is preferably 1.5 μm or more from the viewpoint of facilitating pattern formation and sufficient filling of the conductive material into the conductive layer 63, and 2.5 μm or more. Is more preferable. By doing in this way, the contact area of the electroconductive particle 42 and the conductive layer 63 can be enlarged.

  The width W of the conductive layer 63 is not particularly limited, but is preferably 0.5 to 6 μm. Here, the width W of the conductive layer 63 is a length in a direction perpendicular to the length direction of the conductive layer 63. The lower limit value of the width of the conductive layer 63 is more preferably 1 μm or more, and the upper limit value of the width of the conductive layer 63 is more preferably 5 μm or less. In this case, the visibility of the conductive layer 63 can be lowered, and the connection resistance of the anisotropic conductive connection structure 10 can be reduced as will be described later. Further, “width of the conductive layer 63 / height of the partition wall 61” (so-called aspect ratio of the conductive layer 63) is preferably larger than 1. This is because the visibility of the conductive layer 63 can be lowered in this case.

  Further, it is preferable that the conductive layer 63 does not protrude on the partition wall 61. This is for reducing the visibility of the conductive layer 63.

  Although the method in particular of forming the conductive layer 63 on the uneven | corrugated layer 60 is not restrict | limited, A blade method is mentioned as an example. In this method, a metal particle slurry is applied on the uneven layer 60. Next, surplus metal particle slurry is removed from the uneven layer 60 with a blade. Next, the metal particle slurry remaining in the recess 62 is fired. Through the above steps, the conductive layer 63 is formed on the uneven layer 60.

  The planar shape and the cross-sectional shape of the electrode group 20 and the first electrode terminal 30 can be observed with an SEM (scanning electron microscope).

<2. Configuration of Anisotropic Conductive Connection Structure>
Next, the configuration of the anisotropic conductive connection structure (hereinafter, also simply referred to as “connection structure”) 10 according to the present embodiment will be described with reference to FIG. As shown in FIG. 4, the connection structure 10 includes a substrate 15, a first electrode terminal 30, an anisotropic conductive adhesive layer (hereinafter simply referred to as “adhesive layer”) 40, and an electronic component 50. With. The electronic component 50 includes an electronic component main body 51 and a second electrode terminal 52.

  The adhesive layer 40 is obtained by curing an anisotropic conductive adhesive, and includes a cured resin layer 41 and conductive particles 42. Here, in the present embodiment, the adhesive layer 40 is directly provided on the first electrode terminal 30. That is, in the present embodiment, the first electrode terminal 30 and the second electrode terminal 52 are directly anisotropically conductively connected. The anisotropic conductive adhesive includes a curable resin and conductive particles 42. The curable resin includes a polymerizable compound and a curing initiator.

  The polymerizable compound is a resin that is cured by a curing initiator. The cured polymerizable compound, that is, the cured resin layer 41 adheres the first electrode terminal 30 and the second electrode terminal 52 in the adhesive layer 40 and holds the conductive particles 42 in the adhesive layer 40. To do. Examples of the polymerizable compound include an epoxy polymerizable compound and an acrylic polymerizable compound. The epoxy polymerizable compound is a monomer, oligomer, or prepolymer having one or more epoxy groups in the molecule. As epoxy polymerizable compounds, various bisphenol type epoxy resins (bisphenol A type, F type, etc.), novolac type epoxy resins, various modified epoxy resins such as rubber and urethane, naphthalene type epoxy resins, biphenyl type epoxy resins, phenol novolac type Examples thereof include epoxy resins, stilbene type epoxy resins, triphenolmethane type epoxy resins, dicyclopentadiene type epoxy resins, triphenylmethane type epoxy resins, and prepolymers thereof.

  The acrylic polymerizable compound is a monomer, oligomer, or prepolymer having one or more acrylic groups in the molecule. Examples of acrylic polymerizable compounds include methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, epoxy acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, trimethylol propane triacrylate, dimethylol tricyclodecane diacrylate, and tetramethylene glycol. Tetraacrylate, 2-hydroxy-1,3-diacryloxypropane, 2,2-bis [4- (acryloxymethoxy) phenyl] propane, 2,2-bis [4- (acryloxyethoxy) phenyl] propane, Examples include dicyclopentenyl acrylate, tricyclodecanyl acrylate, tris (acryloxyethyl) isocyanate, and urethane acrylate. That. In the present embodiment, any one of the polymerizable compounds listed above may be used, or two or more may be used in any combination.

  The curing initiator is, for example, a thermosetting initiator. The thermosetting initiator is a material that is cured together with the polymerizable compound by heat. The kind of thermosetting initiator is not particularly limited. Examples of the thermosetting initiator include a thermal anion or thermal cation curing initiator that cures the epoxy polymerizable compound, and a thermal radical polymerization curing agent that cures the acrylic polymerizable compound. In this embodiment, an appropriate thermosetting initiator may be selected depending on the polymerizable compound. In addition, a photocuring initiator is mentioned as another example of a curing initiator. Examples of the photocuring initiator include a photoanion or photocationic curing initiator that cures an epoxy polymerizable compound, and a photo radical polymerization curing agent that cures an acrylic polymerizable compound. In this embodiment, an appropriate photocuring initiator may be selected depending on the polymerizable compound.

  In addition to the above components, the anisotropic conductive adhesive may include a film-forming resin, various additives, and the like. The film-forming resin is added to the anisotropic conductive adhesive when it is desired to form a film in order to make the anisotropic conductive adhesive easy to handle. As the film forming resin, for example, various resins such as an epoxy resin, a phenoxy resin, a polyester urethane resin, a polyester resin, a polyurethane resin, an acrylic resin, a polyimide resin, and a butyral resin can be used. In the present embodiment, only one of these film-forming resins can be used, or two or more can be used in any combination. In addition, it is preferable that film forming resin is a phenoxy resin from a viewpoint of making film forming property and adhesive reliability favorable. In addition, when an anisotropic conductive adhesive is made into a film shape, the thickness of a film (that is, anisotropic conductive film) is not particularly limited. However, if the film becomes too thick, the amount of unnecessary resin becomes too large, causing problems with fluidity. Therefore, 100 micrometers or less are preferable and 40 micrometers or less are more preferable. Since handling will become difficult when it becomes too thin, 5 micrometers or more are preferable and 12 micrometers or more are more preferable.

  Examples of additives that can be added to the anisotropic conductive adhesive include silane coupling agents, inorganic fillers, colorants, antioxidants, and rust inhibitors. The kind of silane coupling agent is not particularly limited. Examples of the silane coupling agent include epoxy-based, amino-based, mercapto-sulfide-based, and ureido-based silane coupling agents. When these silane coupling agents are added to the anisotropic conductive adhesive, adhesion to an inorganic substrate such as a glass substrate can be improved.

  The inorganic filler is an additive for adjusting the fluidity and film strength of the anisotropic conductive adhesive. The kind of inorganic filler is not particularly limited. Examples of the inorganic filler include silica, talc, titanium oxide, calcium carbonate, and magnesium oxide.

  The conductive particle 42 is a material that conducts the first electrode terminal 30 and the second electrode terminal 52 in the adhesive layer 40. Specifically, the conductive particles 42 sandwiched between the first electrode terminal 30 and the second electrode terminal 52 in the adhesive layer 40 are connected to the first electrode terminal 30 and the second electrode terminal 52. Conduct. On the other hand, the other conductive particles 42 (for example, the conductive particles 42 entering the gap between the first electrode terminals 30, the conductive particles 42 entering the gap between the second electrode terminals 52, etc.) No conduction between terminals (that is, a short circuit in which the conductive particles 42 are connected between the first electrode terminals 30 and a short circuit in which the conductive particles 42 are connected between the second electrode terminals 52 are not generated). . Therefore, the conductive particles 42 maintain the insulation between the first electrode terminals 30 and the second electrode terminals 52 in the adhesive layer 40, while maintaining the insulation between the first electrode terminals 30 and the second electrode terminals 52. Can be conducted. That is, the conductive particles 42 are held between the first electrode terminal 30 and the second electrode terminal 52 in the adhesive layer 40, thereby conducting them and making an anisotropic conductive connection. The conductive particles 42 may be dispersed so as not to be short-circuited, and may be arranged so as to be independent of the anisotropic conductive film. This arrangement is appropriately set depending on the size of each electrode terminal, the distance in the arrangement direction of the electrode terminals, and the like, but may be regular.

  Here, the conductive particles 42 that conduct the first electrode terminal 30 and the second electrode terminal 52 are in contact with the conductive layer 63 at the lower end surface thereof. Specifically, a part of the lower end surface, specifically, a portion facing the opening surface of the concave portion 62 is deformed by thermocompression bonding described later, and enters the concave portion 62 to contact the conductive layer 63.

  The conductive particles 42 include a core particle 42a and a coating layer 42b that covers the core particle 42a. That is, the conductive particles 42 are so-called metal-coated resin particles. Of course, the conductive particles 42 may be metal particles. However, as is apparent from FIG. 4, the conductive particles 42 are required to be deformed following the complicated uneven structure of the uneven layer 60. That is, the conductive particles 42 are required to be easily deformed. For this reason, it is preferable that the electroconductive particle 42 is a metal-coated resin particle. The core particles 42a are preferably particles made of a plastic material that is excellent in compressive deformation. Examples of the material constituting the core particle 42a include (meth) acrylate resin, polystyrene resin, styrene- (meth) acrylic copolymer resin, urethane resin, epoxy resin, phenol resin, acrylonitrile / styrene (AS). Examples thereof include resins, benzoguanamine resins, divinylbenzene resins, styrene resins, and polyester resins. For example, when the core particle 42a is formed of a (meth) acrylate resin, the (meth) acrylic resin has a (meth) acrylate ester and, if necessary, a reactive double bond copolymerizable therewith. It is preferable that it is a copolymer with the compound which has and a bifunctional or polyfunctional monomer.

  The covering layer 42b is made of a conductive material. Examples of the material constituting the coating layer 42b include silver, gold, nickel, copper, and palladium. The covering layer 42b may be composed of any one or more of these. In addition, when the electroconductive particle 42 is comprised with a metal particle, the electroconductive particle 42 can be comprised with these materials. A protrusion may be formed on the coating layer 42b. This is to increase the contact area between the coating layer 42 b and the conductive layer 63. The protrusion is made of the same material as that of the covering layer 42b, for example. The length of the protrusion is not particularly limited, but may be 10 to 500 nm or 10% or less of the particle diameter of the conductive particles 42. The particle size, the presence or absence of protrusions, and the length of the conductive particles 42 can be confirmed by observing the coating layer 42b with an SEM or the like, for example.

  In addition, the particle size of the conductive particles 42 is not particularly limited, but is preferably 1/80 or more of the width of the first electrode terminal 30, more preferably 1/20 or more, and 1/10 to 1 Even more preferably, / 5.

  As described above, the electronic component 50 includes the electronic component main body 51 and the second electrode terminal 52. The type of the electronic component main body 51 is not particularly limited. For example, the electronic component main body 51 may be a flexible substrate. A flexible substrate is a substrate formed of a material having high flexibility and flexibility. The material which comprises a flexible substrate is not restrict | limited in particular, The material applied to a well-known flexible substrate is applicable also to this embodiment. Examples of the material constituting the flexible substrate include thin-film metal or glass in addition to resins such as polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, polyethylene, polycarbonate, polyimide, and acrylic resin.

  A plurality of second electrode terminals 52 are provided on the electronic component main body 51. The second electrode terminals 52 are parallel to each other. The width of the second electrode terminal 52 and the space between the terminals may be about the same as those of the first electrode terminal 30. Each of the second electrode terminals 52 is anisotropically conductively connected to the first electrode terminal 30. The material constituting the second electrode terminal 52 is not particularly limited. Examples of the material constituting the second electrode terminal 52 include metals such as aluminum, silver, nickel, copper, and gold, indium tin oxide (ITO), indium zinc oxide (IZO), indium oxide, and conductive tin oxide. , Antimony tin oxide (ATO), and conductive metal oxides such as conductive zinc oxide, and conductive polymers such as polyaniline, polypyrrole, and polythiophene. The metal constituting the second electrode terminal 52 may be plated with various metals (for example, gold, tin, etc.). The second electrode terminal 52 may be made of the same electrode material as that of the first electrode terminal 30.

<3. Preferred conditions for the adhesive layer>
Particularly preferred conditions for the adhesive layer are as follows. This is because the connection resistance of the connection structure 10 is reduced when at least one of these conditions is satisfied.

  (Condition 1) In order to reduce the visibility of the conductive layer 63, the upper limit of the height h of the partition wall 61 is preferably 10 μm or less, more preferably 8 μm or less, and further preferably 6 μm or less. More preferred. In this case, since the contact area between the conductive particles 42 and the conductive layer 63 can be increased, the connection resistance is reduced. The lower limit of the height of the partition wall 61 is not particularly limited, but is preferably 1.5 μm or more from the viewpoint of facilitating pattern formation and sufficiently filling the conductive layer 63 with a conductive material. 5 μm or more is more preferable. By doing in this way, the contact area of the electroconductive particle 42 and the conductive layer 63 can be enlarged.

(Condition 2) The distance from the surface of the conductive layer 63 to the apex of the partition wall 61 and the particle size of the conductive particles 42 before anisotropic conductive connection (that is, the diameter of the sphere) are the conditions of the following formula (1) It is preferable to satisfy.
(1/2) * D ≦ H ≦ (3/4) * D (1)
In Equation (1), H is the distance from the surface of the conductive layer 63 to the apex of the partition wall 61, and D is the particle size of the conductive particles 42 before anisotropic conductive connection. The formula (1) can be rewritten as the following formula (1) ′.
1/2 ≦ H / D ≦ 3/4 (1) ′

  Here, as shown in FIG. 4, the distance H is more specifically the distance from the lowest part (in other words, the part closest to the substrate 15) to the apex of the partition wall 61 on the surface of the conductive layer 63. means. The distance H may be an arithmetic average value of values measured at several measurement points, or may be a value measured at any of the measurement points. The particle size of the conductive particles 42 before anisotropic conductive connection can be measured by observing the conductive particles 42 with an SEM or the like.

  If the distance H is too large with respect to the particle size of the conductive particles 42, the lower end surface of the conductive particles 42 will hardly reach the surface of the conductive layer 63 even if the conductive particles 42 are compressed. The contact area cannot be increased sufficiently. For this reason, the connection resistance of the connection structure 10 increases. On the other hand, if the distance H is too small with respect to the particle size of the conductive particles 42, the conductive particles 42 come into contact with the conductive layer 63 with only slight deformation. Therefore, although the initial connection resistance can be good, the conductive particles 42 are likely to be separated from the conductive layer 63 due to insufficient adhesive strength of the resin or the like. Therefore, the connection resistance may increase with time. Furthermore, when the distance H is too large with respect to the particle size of the conductive particles 42, the conductive layer 63 becomes very thick. Therefore, when the electrode group 20 is formed of such a conductive layer 63, the visibility of the electrode group 20 may increase (that is, it becomes easier to see).

(Condition 3)
It is preferable that the width of the conductive layer 63 and the particle size of the conductive particles 42 before anisotropic conductive connection satisfy the condition of the following formula (2).
W ≦ D ≦ 3 * W (2)
In Equation (2), W is the width of the conductive layer 63, and D is the particle size of the conductive particles 42 before anisotropic conductive connection.
Equation (2) can be rewritten as the following equation (2) ′.
1 ≦ D / W ≦ 3 (2) '

  Here, the width W may be an arithmetic average value of values measured at several measurement points, or may be a value measured at any of the measurement points.

  If the particle diameter of the conductive particles 42 is too small with respect to the width W, the conductive particles 42 are largely buried in the recesses 62. For this reason, it becomes difficult to compress the electroconductive particle 42, or the contact area of the electroconductive particle 42 and the 2nd electrode terminal 52 cannot fully be enlarged. For this reason, the connection resistance of the connection structure 10 increases. On the other hand, if the particle size of the conductive particles 42 is too large with respect to the width W, the contact area between the conductive particles 42 and the conductive layer 63 cannot be sufficiently increased even if the conductive particles 42 are compressed. For this reason, the connection resistance of the connection structure 10 increases.

<4. Manufacturing method of connection structure>
The manufacturing method of the connection structure 10 is not particularly limited. That is, the connection structure 10 can be produced by a normal pressure bonding method using an anisotropic conductive adhesive. That is, the substrate 15 on which the first electrode terminal 30 is formed, the anisotropic conductive adhesive, and the electronic component 50 are sequentially stacked. Here, the electronic component 50 is aligned so that the positions of the first electrode terminal 30 and the second electrode terminal 52 are aligned. Next, a heat tool is pressed onto the electronic component 50 via a buffer material or the like. Next, the first electrode terminal 30 and the second electrode terminal 52 are thermocompression bonded using a heat tool. The connection structure 10 is produced through the above steps.

<1. Example 1>
(1-1. Preparation of first electrode terminal)
A plurality of first electrode terminals 30 were formed on the polyethylene terephthalate substrate 15 in accordance with the method for manufacturing the first electrode terminals 30 described above. Here, the inter-terminal space P and the width W of the first electrode terminal 30 were both 400 μm. That is, L / S = 1/1. The thickness T (see FIG. 3) of the first electrode terminal 30 was 5 μm. That is, the thickness T is the sum of the height h of the partition wall 61 and the thickness of the bottom of the recess 62. Further, the height h of the partition wall 61 was set to 4.0 μm. The conductive material constituting the conductive layer 63 was nanoscale silver particles. Further, the width W of the conductive layer 63 was set to 5.0 μm. Further, when the distance H was measured at several measurement points and arithmetically averaged, the distance H was 3.0 μm.

(1-2. Preparation of flexible substrate)
A flexible substrate (electronic component body 51) was produced by applying a 18 μm thick Ni / Au plating to a 25 μm thick polyimide substrate (SC18-25-00CE manufactured by Nippon Steel Chemical Co., Ltd.). Next, a plurality of second electrode terminals 52 made of Cu were arranged on the flexible substrate. Here, the inter-terminal space of the second electrode terminal 52 was 400 μm and the thickness was 18 μm. L / S was set to 1/1.

(1-3. Preparation of anisotropic conductive film)
30 parts by mass of phenoxy resin (product name: YP50, manufactured by Nippon Steel Chemical Co., Ltd.), 20 parts by mass of polybutadiene powder (product name: XER-91, manufactured by JSR), 10 parts by mass of filler (product name: R202, manufactured by Nippon Aerosil Co., Ltd.), epoxy An adhesive composition was prepared by mixing 40 parts by mass of a compound (product name: NovaCure (registered trademark) HXA3932HP, manufactured by Asahi Kasei E-Materials Co., Ltd.) and conductive particles (manufactured by Nippon Chemical Co., Ltd.). Here, the compounding quantity of electroconductive particle was adjusted so that the number density in an anisotropic conductive film might be set to about 750 piece / mm < ² >. The adhesive composition was applied to a separately prepared release-treated PET film having a thickness of 38 μm with a bar coater and dried to obtain an anisotropic conductive film having a thickness of 18 μm. The particle size of the conductive particles 42 was 5 μm. Therefore, in Example 1, the height h of the partition wall 61 is 4.0 μm, H / D is 3/5 = 0.6, and D / W is 1.0. Therefore, all the conditions 1 to 3 described above are satisfied.

(1-4. Production of connection structure)
The substrate 15 on which the first electrode terminal 30 was formed, the anisotropic conductive film, and the electronic component 50 were sequentially laminated. Here, the electronic component 50 was aligned so that the positions of the first electrode terminal 30 and the second electrode terminal 52 were aligned. Next, a heat tool was pressed onto the electronic component 50 via a buffer material or the like. Subsequently, the 1st electrode terminal 30 and the 2nd electrode terminal 52 were thermocompression-bonded using the heat tool. The connection structure 10 was produced through the above steps. Here, the conditions of thermocompression bonding were 160 degreeC-4MPa-5sec. That is, the temperature of the heat tool is increased to 160 ° C. in 5 seconds from the start of pressure bonding, and the first electrode terminal 30 and the second electrode terminal 52 are thermocompression bonded for 5 seconds at a pressure of 4 MPa. did.

(1-5. Initial connection resistance evaluation)
The connection resistance of the connection structure 10 was measured using a digital multimeter (trade name: Digital Multimeter 7561, manufactured by Yokogawa Electric Corporation). When the connection resistance was 5Ω or less, the evaluation was “A”. When the connection resistance was 15Ω or less, the evaluation was “B”. When the connection resistance was greater than 15Ω, the evaluation was “C”.

(1-6. Connection resistance evaluation after reliability test)
A reliability test was performed by leaving the connection structure 10 in an environment of a temperature of 60 ° C. and a relative humidity of 95% for 500 hours. Then, 1-5. The connection resistance of the connection structure 10 was measured by the same method. When the connection resistance was 10Ω or less, the evaluation was “A”. When the connection resistance was 30Ω or less, the evaluation was “B”. When the connection resistance was 30Ω or more, the evaluation was “C”. In addition, when both the initial evaluation and the evaluation after the reliability test were “A”, the determination was “A”. When both evaluations were “C”, the determination was “C”. In other cases, the determination was “B”. In the determination, if B, there is no practical problem, and if A, it is preferable.

(1-7. Evaluation of peel strength)
The peel strength of the connection structure 10 was measured before and after the reliability evaluation test. The peel strength after the test before the test is the initial peel strength. The peel strength was measured using a tensile tester (trade name: Tensilon, manufactured by A & D). Specifically, the connection structure 10 was cut to a width of 1 cm. Next, the cut connection structure 10 was placed horizontally. Next, a tensile test was performed on the connection structure 10 at an angle of 90 degrees.

<2. Example 2>
The same processing as in Example 1 was performed except that the width W of the conductive layer 63 was set to 2.5 μm. Therefore, in Example 2, the height h of the partition wall 61 is 4 μm, H / D is 3/5 = 0.6, and D / W is 2. Therefore, all the conditions 1 to 3 described above are satisfied.

<3. Example 3>
The same processing as in Example 1 was performed except that the width W of the conductive layer 63 was set to 1.7 μm. Therefore, in Example 3, the height h of the partition wall 61 is 4.0 μm, H / D is 3/5 = 0.6, and D / W is 2.9. Therefore, all the conditions 1 to 3 described above are satisfied.

<4. Example 4>
The same processing as in Example 1 was performed except that the width W of the conductive layer 63 was changed to 6.0 μm. Therefore, in Example 4, the height h of the partition wall 61 is 4.0 μm, H / D is 3/5 = 0.6, and D / W is 0.8. Therefore, conditions 1 and 2 described above are satisfied, but condition 3 is not satisfied.

<5. Example 5>
The same processing as in Example 1 was performed except that the width W of the conductive layer 63 was set to 1.5 μm. Therefore, in Example 5, the height h of the partition wall 61 is 4.0 μm, H / D is 3/5 = 0.6, and D / W is 3.3. Therefore, conditions 1 and 2 described above are satisfied, but condition 3 is not satisfied.

<6. Example 6>
The same processing as in Example 1 was performed except that the distance H was set to 2.5 μm. Therefore, in Example 6, the height h of the partition wall 61 is 4.0 μm, H / D is 2.5 / 5 = 0.5, and D / W is 1.0. Therefore, all the conditions 1 to 3 described above are satisfied.

<7. Example 7>
The same processing as in Example 1 was performed except that the distance H was set to 3.0 μm. Therefore, in Example 7, the height h of the partition wall 61 is 4.0 μm, H / D is 3.0 / 5 = 0.6, and D / W is 1.0. Therefore, all the conditions 1 to 3 described above are satisfied.

<8. Example 8>
The same processing as in Example 1 was performed except that the distance H was 3.75 μm. Therefore, in Example 8, the height h of the partition wall 61 is 4.0 μm, H / D is 3.75 / 5 = 0.75, and D / W is 1.0. Therefore, all the conditions 1 to 3 described above are satisfied.

<9. Example 9>
The same treatment as in Example 1 was performed except that the distance H was 1.5 μm. Therefore, in Example 9, the height h of the partition wall 61 is 4.0 μm, H / D is 1.5 / 5 = 0.3, and D / W is 1.0. Therefore, conditions 1 and 3 described above are satisfied, but condition 2 is not satisfied.

<10. Example 10>
The same treatment as in Example 1 was performed except that the distance H was 4.5 μm. Therefore, in Example 10, the height h of the partition wall 61 is 4.0 μm, H / D is 4.5 / 5 = 0.9, and D / W is 1.0. Therefore, conditions 1 and 3 described above are satisfied, but condition 2 is not satisfied.

<11. Comparative Example>
The same processing as in Example 1 was performed except that the height h of the partition wall 61 was 6.0 μm, the width W of the conductive layer 63 was 6.0 μm, and the distance H was 4.5 μm. Therefore, in the comparative example, H / D is 4.5 / 5.0 = 0.9, and D / W is 0.8. Therefore, all the conditions 1 to 3 described above are not satisfied. The results are summarized in Tables 1 and 2. The underlined numerical values in Tables 1 and 2 are numerical values satisfying either of the conditions 2 and 3.

<12. Evaluation>
In Examples 1 to 10 that satisfy any one or more of Conditions 1 to 3, the initial characteristics and the connection resistance after the reliability test were both good, but the connection resistance of the comparative example was in Examples 1 to 10. It became very large compared. In addition, about the peel strength, any Example and the comparative example were the intensity | strength which does not have a problem in particular. Therefore, in the connection structure 10 according to Examples 1 to 10, the first electrode terminal 30 and the second electrode terminal 52 can be stably anisotropically conductively connected.

  Here, when Examples 1-3 are compared with Example 4, Example 4 has a slightly increased connection resistance after the reliability test. In Example 4, since the particle diameter of the conductive particles 42 is too small with respect to the width W, the conductive particles 42 are largely buried in the recesses 62. For this reason, it is considered that the conductive particles 42 are difficult to compress or the contact area between the conductive particles 42 and the second electrode terminals 52 cannot be sufficiently increased.

  Moreover, when Examples 1-3 are compared with Example 5, Example 5 has the connection resistance after the test before a test rising a little. In Example 5, since the particle diameter of the conductive particles 42 is too large with respect to the width W, the contact area between the conductive particles 42 and the conductive layer 63 can be sufficiently increased even when the conductive particles 42 are compressed. It is thought that it was not possible.

  Moreover, when Examples 6-8 and Example 9 are compared, the connection resistance after the test before the test of Example 9 is slightly increased. In Example 9, since the distance H is too small with respect to the particle size of the conductive particles 42, the conductive particles 42 contact the conductive layer 63 with only slight deformation. Therefore, although the initial connection resistance can be improved, the conductive particles 42 are likely to be separated from the conductive layer 63 due to the spring back of the conductive particles 42 or the like. Therefore, it is considered that the connection resistance increased with time. Furthermore, when the first electrode 30 of Example 9 was visually confirmed, the first electrode terminal 30 was slightly visible although it was at a practically problematic level. In Example 9, since the distance H is small, the conductive layer 63 becomes thick. For this reason, it is considered that such a phenomenon has occurred.

  Further, when Examples 6 to 8 and Example 10 are compared, the connection resistance after the test before the test of Example 10 is slightly increased. In Example 10, since the distance H is too large with respect to the particle size of the conductive particles 42, even if the conductive particles 42 are compressed, the lower end surface of the conductive particles 42 does not easily reach the surface of the conductive layer 63. As a result, it is considered that these contact areas could not be sufficiently increased.

  The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

  For example, in the above embodiment, the connection structure 10 is applied to the touch panel, but the present invention is not limited to such an example. That is, the connection structure 10 can be applied without particular limitation as long as it is in the field of anisotropic conductive connection between an electrode terminal using a metal nanowire and another electrode terminal. For example, it may be used for a functional device in the medical or bio field, and may be used for a battery, energy-related, or in-vehicle (automobile) -related device.

DESCRIPTION OF SYMBOLS 10 Anisotropic conductive connection structure 15 Board | substrate 20 Electrode group 30 1st electrode terminal 40 Anisotropic conductive adhesive layer 41 Cured resin layer 42 Conductive particle 42a Core particle 42b Covering layer 50 Electronic component 51 Electronic component main body 52nd 2 electrode terminals 60 Concavity and convexity layer 61 Partition wall 62 Concavity 63 Conductive layer

Claims (7)

A substrate,
A first electrode terminal formed on the substrate;
An electronic component including a second electrode terminal;
An anisotropic conductive adhesive layer containing conductive particles that connect the first electrode terminal and the second electrode terminal;
The first electrode terminal is an anisotropic conductive connection structure including a plurality of partition walls disposed on the substrate and a conductive layer disposed between the partition walls.   The anisotropic conductive connection structure according to claim 1, wherein a height of the partition wall is 10 μm or less. The anisotropy according to claim 1 or 2, wherein the distance from the surface of the conductive layer to the top of the partition and the particle size of the conductive particles before anisotropic conductive connection satisfy the condition of the following mathematical formula (1). Conductive connection structure.
(1/2) * D ≦ H ≦ (3/4) * D (1)
In Formula (1), H is a distance from the surface of the conductive layer to the top of the partition wall, and D is a particle size of the conductive particles before anisotropic conductive connection. The anisotropic conductive according to any one of claims 1 to 3, wherein the width of the conductive layer and the particle size of the conductive particles before the anisotropic conductive connection satisfy a condition of the following formula (2). Connection structure.
W ≦ D ≦ 3 * W (2)
In Formula (2), W is the width of the conductive layer, and D is the particle size of the conductive particles before anisotropic conductive connection.   The anisotropic conductive connection structure according to claim 1, wherein the conductive particles include core particles containing a resin and a conductive layer that covers a surface of the core particles.   A touch panel provided with the anisotropic conductive connection structure of any one of Claims 1-5. An image display device comprising the touch panel according to claim 6.

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