JP2009170898A - Circuit connecting material and connecting structure of circuit member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circuit connecting material having higher capturing efficiency of electrically conductive particles on electrodes and superior connection reliability than those of conventional ones, and also to provide a connecting structure of a circuit member using the same. <P>SOLUTION: The circuit connecting material 1 intervening between facing circuit electrodes 2 and 8 and imparting pressure to them to electrically connect the electrodes in the pressure imparting direction has a two layer configuration in which an electrically conductive anisotropic adhesive layer 15 in which conductive particles 7 are dispersed and an insulating adhesive layer 16 are laminated, where the relation between the average particle size "a" of the electrically conductive particles and the thickness "b" of the anisotropic electrically conductive adhesive layer satisfies the following formula (1): a≥b. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a circuit connection material and a circuit member connection structure using the same.

  A circuit connecting material that heats and presses opposite circuits to electrically connect electrodes in the pressing direction, for example, an anisotropic conductive adhesive film in which conductive particles are dispersed in an epoxy adhesive or an acrylic adhesive, Widely used for electrical connection between TCP (Tape Carrier Package) or COF (Chip On Flex) and LCD panel, or TCP or COF and printed wiring board, which is mainly equipped with a semiconductor that drives liquid crystal display (LCD) ing.

  Recently, even when semiconductors are directly mounted face-down on LCD panels and printed wiring boards, flip chip mounting, which is advantageous for thinning and narrow pitch connection, has been adopted instead of the conventional wire bonding method. However, anisotropic conductive adhesive films are used as circuit connection materials (see, for example, Patent Documents 1 to 4).

  Further, in recent years, with the increase in COF and fine pitch of LCD modules, there is a problem that a short circuit occurs between adjacent electrodes when connecting using a circuit connecting material. As these countermeasures, there is a technique for preventing short circuit by dispersing insulating particles in an adhesive component (see, for example, Patent Documents 5 to 9).

In addition, in order to adhere to a wiring member made of an insulating organic material or glass, or a wiring member having silicon nitride, silicone resin and / or polyimide resin on at least a part of the surface, the adhesive component contains silicone particles. In order to reduce internal stress based on the difference in coefficient of thermal expansion after bonding, there is a technique of dispersing rubber particles in an adhesive (for example, see Patent Document 11).
JP 59-120436 A JP-A-60-191228 JP-A-1-251787 JP-A-7-90237 JP 51-20941 A JP-A-3-29207 JP-A-4-174980 Japanese Patent No. 3048197 Japanese Patent No. 3477367 International Publication No. 01/014484 Pamphlet JP 2001-323249 A

  However, these conventional circuit connection materials have a problem that a short circuit occurs because the flowing conductive particles are dammed and aggregated by the protrusions of the organic film formed on the glass edge portion of the glass serving as the substrate. As a countermeasure, it is required to improve the trapping efficiency of the conductive particles on the electrode and to prevent the short-circuit due to the aggregation of the conductive particles by reducing unnecessary conductive particles.

  In view of the above circumstances, the present invention provides a circuit connection material that has a higher efficiency of capturing conductive particles on an electrode than a conventional circuit connection material and is excellent in connection reliability, and a circuit member connection structure using the circuit connection material. For the purpose.

The present invention relates to a circuit connecting material that is interposed between circuit electrodes facing each other and presses opposite circuit electrodes to electrically connect the electrodes in the pressurizing direction. A two-layer structure in which the agent layer and the insulating adhesive layer are laminated, and the average particle diameter a of the conductive particles and the thickness b of the anisotropic conductive adhesive layer satisfy the relationship of the following formula (1) The circuit connection material is provided.
a ≧ b (1)

  According to such a circuit connection material, the conductive particle capturing efficiency on the electrode is higher than that of the conventional circuit connection material, and the connection reliability is also excellent.

  Although the reason why such an effect can be obtained by the circuit connecting material of the present invention is not necessarily clear, the present inventors' idea will be described with reference to FIGS.

  FIG. 2 shows a circuit electrode 6 provided on a circuit board 5 and a circuit electrode 2 provided on the circuit board 4 by using a film-like circuit connection material 1 containing conventional conductive particles 7 and a resin 9. It is a schematic cross section which shows the behavior of the electroconductive particle 7 when these are electrically connected.

  When the circuit boards 4 and 5 shown in FIG. 2A are pressed and connected, the film-like circuit connecting material is compressed, and in a direction parallel to the main surface of the board as indicated by the arrow in FIG. A force is generated to move the conductive particles. As a result, the conductive particles move greatly, and the conductive particles reach the resist 8 which is an insulating portion, so it is considered that a short circuit occurs.

  As shown in FIG. 3, a film-like circuit connection material 1 having a configuration in which an anisotropic conductive adhesive layer 15 containing a conventional conductive particle 7 and resin 9 and an insulating adhesive layer 16 are laminated is used. Even in this case, the conductive particles move greatly due to the pressurization, thereby causing a short circuit.

  On the other hand, as shown in FIG. 4, when the film-like circuit connecting material 1 of the present invention is used, the average particle diameter of the conductive particles is larger or the same as the thickness of the anisotropic conductive adhesive layer. The present inventors consider that the moving distance of the conductive particles can be reduced, thereby improving the trapping efficiency of the conductive particles on the electrode and preventing a short circuit.

  The conductive particles preferably have an average particle size of 2 to 6 μm, and the anisotropic conductive adhesive layer preferably has a thickness of 1 to 5 μm.

  The thickness of the anisotropic conductive adhesive layer is preferably 20 to 100% of the average particle diameter of the conductive particles, and the conductive particles are composed of the anisotropic conductive adhesive layer and the insulating adhesive. Preferably it exists across the layers.

  The minimum melt viscosity ratio of the anisotropic conductive adhesive layer to the insulating adhesive layer is preferably at least 10 times or more.

  In the present invention, the first circuit member having the first connection terminal and the second circuit member having the second connection terminal are arranged so that the first connection terminal and the second connection terminal face each other. The first connection terminal and the second connection terminal are disposed between the first connection terminal and the second connection terminal that are disposed opposite to each other, and the circuit connection material of the present invention is interposed between the first connection terminal and the second connection terminal. A circuit member connection structure is provided.

  According to such a circuit member connection structure, since the circuit connection material of the present invention is used, the trapping efficiency of the conductive particles on the electrode is high and the connection reliability is also excellent.

  According to the present invention, there is provided a circuit connection material that has higher efficiency of capturing conductive particles on the electrode than conventional circuit connection materials, can prevent short-circuiting due to aggregation of conductive particles, and is excellent in connection reliability. The connection structure of the circuit member using can be provided.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as necessary.

  A circuit connection material having a two-layer structure according to the present invention is a circuit connection material that is interposed between circuit electrodes facing each other, pressurizes circuit electrodes facing each other, and electrically connects the electrodes in the pressurizing direction. An anisotropic conductive adhesive layer in which particles are dispersed and an insulating adhesive layer are laminated.

  Examples of the conductive particles include metal particles such as Au, Ag, Ni, Cu, and solder, and carbon. The conductive particles may be particles in which core particles are covered with one or more layers, and the outermost layer is a conductive layer. In this case, in order to obtain a sufficient pot life, the outermost layer is preferably Au, Ag, or a platinum group noble metal, more preferably Au, than transition metals such as Ni and Cu.

  The conductive particles may be those in which the surface of a transition metal such as Ni is coated with a noble metal such as Au. Furthermore, the conductive particles may be those obtained by coating nonconductive glass, ceramic, plastic, or other insulating particles with a conductive material such as metal. When conductive particles are made of insulating particles coated with a conductive material and the outermost layer is precious metal and the core insulating particles are plastic, or the conductive particles are hot-melt metal particles, they are deformed by heating and pressing. This is preferable because the contact area with the electrode increases at the time of connection and the reliability is improved.

  In order to obtain good resistance, the thickness of the noble metal coating layer is preferably 100 mm or more. However, when a noble metal coating layer is provided on a transition metal such as Ni, the oxidation-reduction action caused by the noble metal coating layer deficiency or the noble metal coating layer deficiency generated when the conductive particles are mixed and dispersed. Since free radicals are generated and pot life is reduced, the thickness of the coating layer is preferably 300 mm or more when using a radical polymerization type adhesive component.

  Although electroconductive particle can be contained normally in 0.1-30 volume parts with respect to 100 volume parts of adhesive components, suitable content changes with uses. For example, 0.1 to 10 parts by volume is more preferable in order to more sufficiently prevent a short circuit between adjacent circuits due to conductive particles.

The average particle diameter of the conductive particles is preferably 1 to 10 μm, preferably 1 to 8 μm, and preferably 2 to 6 μm from the viewpoint that the short circuit between adjacent electrodes decreases when the electrode height is lower than the electrode height of the circuit to be connected. More preferably, it is 3-5 μm, and most preferably 3-4 μm. Further, those having a 10% compression modulus (K value) of 100 to 1000 kgf / mm ² can be appropriately selected and used.

  The average particle diameter of the conductive particles can be determined as follows. That is, one core particle is arbitrarily selected, and this is observed with a differential scanning electron microscope, and its maximum diameter and minimum diameter are measured. The square root of the product of the maximum diameter and the minimum diameter is defined as the particle diameter of the particle. By this method, the particle diameter of 50 arbitrarily selected core particles is measured, and the average value is taken as the average particle diameter of the conductive particles.

  The thickness of the anisotropic conductive adhesive layer is preferably 1 to 5 μm and more preferably 1 to 4 μm in order to suppress the flow of the conductive particles.

  The thickness of the insulating adhesive layer is preferably 2 to 21 μm, and more preferably 4 to 14 μm.

In the circuit connection material of the present invention, the average particle diameter a of the conductive particles and the thickness b of the anisotropic conductive adhesive layer satisfy the relationship of the following formula (1).
a ≧ b (1)

  The anisotropic conductive adhesive layer has a thickness of preferably 20 to 100% and more preferably 25 to 75% with respect to the average particle diameter of the conductive particles.

  The minimum melt viscosity ratio of the anisotropic conductive adhesive layer to the insulating adhesive layer is preferably at least 10 times or more. Thereby, the movement inhibitory effect of the conductive particles during pressurization is further improved. Thereby, the movement inhibitory effect of the conductive particles during pressurization is further improved. In addition, although the upper limit of the said minimum melt viscosity ratio is not specifically limited, For example, it can be 1000 times or less.

  The circuit connection material of the present invention preferably contains (a) an epoxy resin and (b) an adhesive composed of a latent curing agent as an adhesive component in the anisotropic conductive adhesive layer and the insulating adhesive layer.

(A) Epoxy resins include bisphenol type epoxy resins derived from epichlorohydrin and bisphenol A, bisphenol F and / or bisphenol AD, and epoxy novolac resins and naphthalene rings derived from epichlorohydrin and phenol novolac or cresol novolac. Naphthalene type epoxy resin having a skeleton containing, glycidylamine, glycidyl ether, biphenyl, alicyclic, etc., each epoxy compound having two or more glycidyl groups in one molecule or a mixture of two or more Can be used. For these epoxy resins, it is preferable to use a high-purity product in which impurity ions (Na ⁺ , Cl ^−, etc.), hydrolyzable chlorine and the like are reduced to 300 ppm or less, in order to prevent electron migration.

  (B) Examples of the latent curing agent include imidazole series, hydrazide series, boron trifluoride-amine complex, sulfonium salt, amine imide, polyamine salt, dicyandiamide, and the like. These can be used individually by 1 type or in mixture of 2 or more types, You may mix and use a decomposition accelerator, an inhibitor, etc. In addition, those encapsulating these curing agents with polyurethane-based or polyester-based polymeric substances and the like and microencapsulated are preferable because the pot life is extended.

  The circuit connecting material of the present invention includes (c) a curing agent that generates free radicals by heating or light (hereinafter, also referred to as “free radical generator”), and (d) an adhesive comprising a radical polymerizable substance. Is preferably contained as an adhesive component in the anisotropic conductive adhesive layer and the insulating adhesive layer.

  (C) The free radical generator is one that decomposes by heating a peroxide compound, an azo compound or the like to generate free radicals, and is appropriately selected depending on the intended connection temperature, connection time, pot life, etc. However, from the viewpoint of high reactivity and pot life, an organic peroxide having a half-life of 10 hours at a temperature of 40 ° C. or more and a half-life of 1 minute at a temperature of 180 ° C. or less is preferred. In this case, the amount of the (c) free radical generator is preferably 0.05 to 10% by weight, more preferably 0.1 to 5% by weight, based on the entire solid content of the adhesive.

  (C) Specifically, the free radical generator can be selected from diacyl peroxide, peroxydicarbonate, peroxyester, peroxyketal, dialkyl peroxide, hydroperoxide, and the like. In order to suppress the corrosion of the connection terminals of the circuit member, it is preferably selected from peroxyesters, dialkyl peroxides, and hydroperoxides, and more preferably selected from peroxyesters that provide high reactivity.

  Examples of the diacyl peroxide include isobutyl peroxide, 2,4-dichlorobenzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, and succinic peroxide. , Benzoylperoxytoluene, benzoyl peroxide and the like.

  Examples of peroxydicarbonate include di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, bis (4-t-butylcyclohexyl) peroxydicarbonate, di-2-ethoxymethoxyperoxydicarbonate, Examples include di (2-ethylhexylperoxy) dicarbonate, dimethoxybutylperoxydicarbonate, di (3-methyl-3-methoxybutylperoxy) dicarbonate, and the like.

  Examples of peroxyesters include cumyl peroxyneodecanoate, 1,1,3,3-tetramethylbutylperoxyneodecanoate, 1-cyclohexyl-1-methylethylperoxynoedecanoate, t -Hexylperoxyneodecanoate, t-butylperoxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-bis ( 2-ethylhexanoylperoxy) hexane, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethyl Hexanonate, t-butylperoxyisobutyrate, 1,1-bis (t-butylperoxy) cyclo Xane, t-hexylperoxyisopropyl monocarbonate, t-butylperoxy-3,5,5-trimethylhexanonate, t-butylperoxylaurate, 2,5-dimethyl-2,5-bis (m- Toluoyl peroxy) hexane, t-butyl peroxyisopropyl monocarbonate, t-butyl peroxy-2-ethylhexyl monocarbonate, t-hexyl peroxybenzoate, t-butyl peroxyacetate and the like.

  Examples of the peroxyketal include 1,1-bis (t-hexylperoxy) -3,5,5-trimethylcyclohexane, 1,1-bis (t-hexylperoxy) cyclohexane, 1,1-bis ( t-Butylperoxy) -3,5,5-trimethylcyclohexane, 1,1- (t-butylperoxy) cyclododecane, 2,2-bis (t-butylperoxy) decane and the like.

  Examples of the dialkyl peroxide include α, α′-bis (t-butylperoxy) diisopropylbenzene, dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, t -Butyl cumyl peroxide etc. are mentioned.

  Examples of the hydroperoxide include diisopropylbenzene hydroperoxide and cumene hydroperoxide.

  These (c) free radical generators can be used singly or in combination of two or more, and may be used by mixing a decomposition accelerator, an inhibitor and the like.

  (D) The radically polymerizable substance is a substance having a functional group that is polymerized by radicals, and specific examples thereof include acrylates, methacrylates, maleimide compounds, and the like. (D) The compounding amount of the radically polymerizable substance is preferably 25 to 55% by weight and more preferably 30 to 50% by weight with respect to the entire solid content of the adhesive.

  Examples of the acrylate (methacrylate) include urethane acrylate, methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, trimethylolpropane triacrylate, and tetramethylolmethane tetraacrylate. 2-hydroxy-1,3-diaacryloxypropane, 2,2-bis [4- (acryloxymethoxy) phenyl] propane, 2,2-bis [4- (acryloxypolyethoxy) phenyl] propane, di Cyclopentenyl acrylate, tricyclodecanyl acrylate, bis (acryloxyethyl) isocyanurate, ε-caprolactone modified tris (a Rirokishiechiru) isocyanurate, tris (acryloyloxyethyl) isocyanurate.

  As the maleimide compound, those containing at least two maleimide groups in the molecule are preferable. For example, 1-methyl-2,4-bismaleimidebenzene, N, N′-m-phenylenebismaleimide, N, N ′ -P-phenylene bismaleimide, N, N'-m-toluylene bismaleimide, N, N'-4,4-biphenylene bismaleimide, N, N'-4,4- (3,3'-dimethyl-biphenylene ) Bismaleimide, N, N′-4,4- (3,3′-dimethyldiphenylmethane) bismaleimide, N, N′-4,4- (3,3′-diethyldiphenylmethane) bismaleimide, N, N ′ -4,4-diphenylmethane bismaleimide, N, N'-4,4-diphenylpropane bismaleimide, N, N'-4,4-diphenyl ether bisma Imido, N, N′-3,3′-diphenylsulfone bismaleimide, 2,2-bis [4- (4-maleimidophenoxy) phenyl] propane, 2,2-bis [3-s-butyl-4,8 -(4-maleimidophenoxy) phenyl] propane, 1,1-bis [4- (4-maleimidophenoxy) phenyl] decane, 4,4'-cyclohexylidene-bis [1- (4-maleimidophenoxy) -2 -Cyclohexyl] benzene, 2,2-bis [4- (4-maleimidophenoxy) phenyl] hexafluoropropane and the like. These may be used alone or in combination of two or more, or may be used in combination with allyl compounds such as allylphenol, allylphenyl ether, and allyl benzoate.

  Such (d) radical polymerizable substances can be used alone or in combination of two or more. (D) The radically polymerizable substance preferably contains at least a radically polymerizable substance having a viscosity at 25 ° C. of 100,000 to 1,000,000 mPa · s, and particularly has a viscosity (25 ° C.) of 100,000 to 500,000 mPa · s. It is preferable to contain a sex substance. (D) The viscosity of the radical polymerizable substance can be measured using a commercially available E-type viscometer.

  (D) Among radically polymerizable substances, urethane acrylate or urethane methacrylate is preferable from the viewpoint of adhesiveness, and after crosslinking with an organic peroxide used for improving heat resistance, Tg of 100 ° C. or more alone. It is particularly preferable to use in combination with a radically polymerizable substance showing As such a radically polymerizable substance, a substance having a dicyclopentenyl group, a tricyclodecanyl group and / or a triazine ring can be used. In particular, a radical polymerizable substance having a tricyclodecanyl group or a triazine ring is preferably used.

  In the circuit connection material of the present invention, a polymerization inhibitor such as hydroquinone or methyl ether hydroquinone may be used as necessary.

  Further, when 0.1 to 10% by weight of a radical polymerizable substance having a phosphate ester structure is used, the adhesive strength on the surface of an inorganic substance such as a metal is preferably improved, and is 0.5 to 5% by weight. And more preferred. The radically polymerizable substance having a phosphoric ester structure is obtained as a reaction product of phosphoric anhydride and 2-hydroxyl (meth) acrylate. Specific examples include 2-methacryloyloxyethyl acid phosphate, 2-acryloyloxyethyl acid phosphate, and the like. These can be used singly or in combination of two or more.

  In addition, the circuit connection material of the present embodiment is preferably used in the form of a film because it is excellent in handleability. In that case, it may contain a film-forming polymer. Film-forming polymers include polystyrene, polyethylene, polyvinyl butyral, polyvinyl formal, polyimide, polyamide, polyester, polyvinyl chloride, polyphenylene oxide, urea resin, melamine resin, phenol resin, xylene resin, epoxy resin, polyisocyanate resin, Phenoxy resin, polyimide resin, polyester urethane resin or the like is used. Among these, a resin having a functional group such as a hydroxyl group is more preferable because adhesiveness can be improved. Also, those obtained by modifying these polymers with radically polymerizable functional groups can be used. These polymers preferably have a weight average molecular weight of 10,000 or more. Moreover, since mixing property will fall when a weight average molecular weight becomes 1000000 or more, it is preferable in it being less than 1 million.

  Furthermore, the circuit connection material of the present embodiment includes a filler, a softener, an accelerator, an anti-aging agent, a colorant, a flame retardant, a thixotropic agent, a coupling agent, a phenol resin, a melamine resin, an isocyanate, and the like. It can also be contained.

  When the circuit connection material of this embodiment contains a filler, it is preferable because improvement in connection reliability and the like can be obtained. The filler can be used if its maximum diameter is smaller than the particle diameter of the conductive particles, and the range of 5 to 60% by volume is preferable. If it exceeds 60% by volume, the effect of improving reliability is saturated.

  As the coupling agent, a compound containing one or more groups selected from the group consisting of a vinyl group, an acrylic group, an amino group, an epoxy group, and an isocyanate group is preferable from the viewpoint of improving adhesiveness.

  The anisotropic conductive adhesive layer and the insulating adhesive layer can contain the above-mentioned adhesive component, but it is preferable that at least some of the components of the respective layers are different.

  In addition, the circuit connection material of the configuration of the present embodiment is divided into a layer containing a reactive resin and a layer containing a latent curing agent, or a layer containing a curing agent that generates free radicals and conductive particles. In the case where the layer is separated, the effect of improving pot life can be obtained in addition to the conventional effect of high definition.

  The circuit connection material of the present embodiment is also useful as a material for bonding an IC chip and a substrate or bonding electric circuits. That is, the first circuit member having the first connection terminal and the second circuit member having the second connection terminal are arranged so that the first connection terminal and the second connection terminal face each other, The circuit connection material of the present invention is interposed between the first connection terminal and the second connection terminal that are arranged opposite to each other, and heated and pressed to electrically connect the first connection terminal and the second connection terminal. By connecting to the circuit member, it is possible to produce a circuit member connection structure.

  Examples of such circuit member connection structures include chip components such as semiconductor chips, resistor chips, and capacitor chips, and substrates such as printed boards. These circuit member connection structures are usually provided with a large number of connection terminals (or a single terminal in some cases), and at least one set of circuit member connection structures is provided in the connection structure of these circuit members. At least a part of the terminals are arranged opposite to each other, an adhesive is interposed between the opposed arranged connection terminals, and the connection terminals arranged opposite to each other by heating and pressing are electrically connected to form a circuit board. By heating and pressurizing at least one set of the circuit member connection structure, the connection terminals arranged opposite to each other can be electrically connected via conductive particles of an anisotropic conductive adhesive (circuit connection material).

  Next, an embodiment of a method for manufacturing a circuit member connection structure according to the present invention will be described. FIG. 1 is a process cross-sectional view schematically showing a method for manufacturing a circuit member connection structure according to an embodiment of the present invention. FIG. 1A is a cross-sectional view of the circuit members before connecting the circuit members, and FIG. 1B is a cross-sectional view of the connection structure of the circuit members when connecting the circuit members. c) is a cross-sectional view of a circuit member connection structure in which circuit members are connected to each other.

  First, as shown in FIG. 1A, a film-like circuit connection material 1 formed by forming a circuit connection material into a film shape is placed on the circuit electrode 2 provided on the LCD panel 3.

  Next, as shown in FIG. 1B, the circuit board 5 on which the circuit electrode 6 is provided while being aligned is placed on the circuit-connecting material 1 in the form of a film so that the circuit electrode 2 and the circuit electrode 6 face each other. The film-like circuit connecting material 1 is interposed between the circuit electrode 2 and the circuit electrode 6. The circuit electrodes 2 and 6 have a structure in which a plurality of electrodes are arranged in the depth direction (not shown).

  The film-like circuit connecting material 1 is easy to handle because it is in the form of a film. Therefore, the film-like circuit connecting material 1 can be easily interposed between the circuit electrode 2 and the circuit electrode 6, and the connection work between the LCD panel 3 and the circuit board 5 can be facilitated.

  Next, the film-like circuit connecting material 1 is pressed in the direction of arrow A in FIG. 1B through the LCD panel 3 and the circuit board 5 while being heated to perform a curing process. As a result, a circuit member connection structure 20 in which the circuit members are connected to each other as shown in FIG. 1C is obtained. As a method for the curing treatment, one or both of heating and light irradiation can be employed depending on the adhesive composition to be used.

  The circuit connection material of the present embodiment is one in which the adhesive melts and flows at the time of connection and obtains connection of the opposite circuit electrodes, and then cures to hold the connection. The fluidity of the adhesive is an important factor. is there. When a circuit connection material of thickness 35 μm, 5 mm × 5 mm is sandwiched between a glass plate of thickness 0.7 mm, 15 mm × 15 mm and heated and pressed under the conditions of 170 ° C., 2 MPa, 10 seconds, the initial adhesive The value of fluidity (B) / (A) expressed using the area (A) of the surface and the area (B) of the main surface after heating and pressing is preferably 1.3 to 3.0. 1.5 to 2.5 is more preferable. If it is less than 1.3, the fluidity is poor and there is a tendency that good connection cannot be obtained. If it exceeds 3.0, bubbles tend to be generated and the reliability tends to be poor.

  100-3000 MPa is preferable and, as for the elasticity modulus in 40 degreeC after hardening of the circuit connection material of this embodiment, 500-2000 MPa is more preferable.

  In the circuit electrode connection method of this embodiment, after forming a circuit connection material having curability by heat or light on one electrode circuit whose surface is a metal selected from gold, silver, tin and white metal, the other These circuit electrodes can be aligned, heated and pressurized to be connected.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.
Example 1
(D) As radically polymerizable substances, urethane acrylate (product name: UA-5500T, manufactured by Shin-Nakamura Chemical Co., Ltd.) 20 parts by weight, bis (acryloxyethyl) isocyanurate (product name: M-215, manufactured by Toagosei Co., Ltd.) ) 15 parts by weight, dimethylol tricyclodecane diacrylate (product name: DCP-A, manufactured by Kyoeisha Chemical Co., Ltd.), 5 parts by weight, 2-methacryloyloxyethyl acid phosphate (product name: P-2M, Kyoeisha Chemical Co., Ltd.) 3 parts by weight, (c) 4 parts by weight of benzoyl peroxide (product name: Nyper BMT-K, manufactured by NOF Corporation) as a free radical generator, polyester urethane resin (product name: UR4800, manufactured by Toyobo Co., Ltd.) in toluene / Methyl ethyl ketone = mixed in 60 parts by weight of a 40% by weight solution obtained by dissolving in a 50/50 mixed solvent and stirred. It was Indah resin. Furthermore, a conductive layer having an average particle diameter of 4 μm (10% compression), in which a nickel layer having a thickness of 0.2 μm is provided on the surface of particles having polystyrene as a core, and a gold layer having a thickness of 0.04 μm is provided outside the nickel layer. 3% by volume of elastic modulus (K value): 410 kgf / mm ² ) is dispersed in the binder resin, and silicone fine particles having an average particle diameter of 2 μm (product name: KMP-605, manufactured by Shin-Etsu Chemical Co., Ltd.) are added to the binder resin 100. A dispersion was obtained by dispersing 20 parts by weight with respect to parts by weight. This dispersion is applied to a PET film having a surface of 50 μm on one surface using a coating apparatus and dried with hot air at 70 ° C. for 10 minutes, whereby an anisotropic conductive adhesive having an adhesive layer thickness of 4.0 μm is applied. Agent layer A (width 15 cm, length 70 m) was obtained.
Next, (d) 20 parts by weight of urethane acrylate (product name: UA-5500T, manufactured by Shin-Nakamura Chemical Co., Ltd.), bis (acryloxyethyl) isocyanurate (product name: M-215, Toagosei Co., Ltd.) as a radical polymerizable substance 20 parts by weight, dimethylol tricyclodecane diacrylate (product name: DCP-A, manufactured by Kyoeisha Chemical Co., Ltd.) 10 parts by weight, 2-methacryloyloxyethyl acid phosphate (product name: P-2M, Kyoeisha) 3 parts by weight (made by Kagaku Co.), (c) 4 parts by weight of benzoyl peroxide (product name: Nyper BMT-K, manufactured by NOF Corporation) as a free radical generator, polyester urethane resin (product name: UR4125, manufactured by Toyobo Co., Ltd.) Was dissolved in a mixed solvent of toluene / methyl ethyl ketone = 50/50 and mixed with 50 parts by weight of a 23% by weight solution obtained. , It was stirred binder resin. This binder resin is applied to a PET film having a surface treated with a thickness of 50 μm using a coating apparatus, and dried with hot air at 70 ° C. for 10 minutes, whereby an insulating adhesive layer B having a thickness of 10 μm (width 15 cm, A length of 70 m) was obtained.
The obtained adhesive layers A and B are overlapped in the direction in which the adhesive faces each other, and a laminator (Dupont RISTON, model: HRL, roll pressure is spring load only, roll temperature 40 ° C., speed 50 cm / min) is used. After laminating, the anisotropic conductive adhesive layer A side PET was peeled off to obtain an anisotropic conductive adhesive having a thickness of 14 μm (width 15 cm, length 60 m). The obtained anisotropic conductive adhesive was cut into a width of 1.5 mm, and wound on a side surface (thickness 1.7 mm) of a plastic reel having an inner diameter of 40 mm and an outer diameter of 48 mm with the adhesive film surface facing inward for 50 m. A circuit connection material was obtained.

(Examples 2 to 5)
A tape-shaped circuit connecting material was produced in the same manner as in Example 1 except that the particle diameter of the conductive particles and the thickness of each adhesive layer were changed as shown in Table 1.

(Comparative Example 1)
As in Example 1, except that the particle diameter of the conductive particles and the thickness of the insulating adhesive layer B were changed as shown in Table 2, and the anisotropic conductive adhesive layer A was made thicker than the conductive particle diameter. Thus, a tape-like circuit connecting material was produced.

(Comparative Example 2)
The particle size of the conductive particles, the anisotropic conductive adhesive layer A, and the thickness of the insulating adhesive layer B are changed as shown in Table 2, and the adhesive composition of the anisotropic conductive adhesive layer A and the insulating adhesive layer B is changed. A tape-like circuit connecting material was produced in the same manner as in Example 1 except that the (melt viscosity) was the same.

(Comparative Example 3)
A tape-shaped circuit connecting material was produced in the same manner as in Example 1 except that the particle diameter of the conductive particles and the thickness of the anisotropic conductive adhesive layer A were changed as shown in Table 2 to obtain a single layer.

(Preparation of evaluation connector)
A connection body obtained as follows was used for measurement of connection resistance and adhesive force.
The adhesive coated surface of the circuit connecting material (width 1.5 mm, length 3 cm) obtained in the examples and comparative examples was heated and pressed at 70 ° C. and 1 MPa for 2 seconds to form an ITO-coated glass substrate (15Ω) □) Transferred onto and peeled off the PET film. Next, a flexible circuit board (FPC) having 600 tin-plated copper circuits with a pitch of 50 μm and a thickness of 8 μm was placed on the transferred adhesive, and temporarily fixed by pressing at 24 ° C. and 0.5 MPa for 1 second. A glass substrate on which this FPC is temporarily fixed with a circuit connecting material is placed in a main pressure bonding apparatus, and 200 μm-thick silicone rubber is used as a cushioning material, and heated and pressurized at 170 ° C. and 3 MPa for 6 seconds from the flexible wiring board side by a heat tool. Then, connection was made over a width of 1.5 mm to obtain a connection body for evaluation (circuit member connection structure).

The connection body obtained as follows was used for the measurement of the conductive particle trapping efficiency.
The adhesive surface of the circuit connection material (width 1.5 mm, length 3 cm) obtained in Examples and Comparative Examples was heated and pressed at 70 ° C. and 1 MPa for 2 seconds to obtain an Al-coated glass substrate (10Ω) □) Transferred onto and peeled off the PET film. Next, a flexible circuit board (FPC) having 600 tin-plated copper circuits with a pitch of 50 μm and a thickness of 8 μm was placed on the transferred adhesive, and temporarily fixed by pressing at 24 ° C. and 0.5 MPa for 1 second. A glass substrate on which this FPC is temporarily fixed with a circuit connecting material is placed in a main pressure bonding apparatus, and 200 μm-thick silicone rubber is used as a cushioning material, and heated and pressurized at 170 ° C. and 3 MPa for 6 seconds from the flexible wiring board side by a heat tool. Then, connection was made over a width of 1.5 mm to obtain a connection body for evaluation.

(Measurement of connection resistance)
The resistance value between adjacent circuits of the FPC including the connection part of the connection body described above was measured with a multimeter (device name: TR6845, manufactured by Advantest Corporation). For the resistance value, 40 points of resistance between adjacent circuits were measured, and an average value was obtained. The obtained results are shown in Tables 3 and 4.

(Measurement of adhesive strength)
The above-mentioned connection body was peeled 90 degrees at a peeling speed of 50 mm / min to measure the adhesive force. The obtained results are shown in Tables 3 and 4.

(Measurement of conductive particle capture efficiency)
The number of conductive particles trapped on the electrodes in the above-mentioned connection body was measured for 20 electrodes by Nomarski differential interference observation from the glass side using a BH3-MJL liquid crystal panel inspection microscope manufactured by Olympus Corporation. It was determined by measuring and calculating the average value. On the other hand, the number of conductive particles per unit area in the adhesive was measured with a BH3-MJL liquid crystal panel inspection microscope manufactured by Olympus Corporation. The obtained result was substituted into the following equation to calculate the conductive particle trapping efficiency.
Conductive particle capture efficiency = (number of conductive particles on electrode [number]) × 100 / {(number of conductive particles per unit area in adhesive [number / mm ² ]) × (connection area [mm ² ] per electrode) }
The obtained results are shown in Tables 3 and 4.

  As is clear from Tables 3 and 4, the circuit connection materials of Examples 1 to 5 improved the efficiency of capturing conductive particles on the electrodes compared to the circuit connection materials of Comparative Examples 1 to 3, and short-circuits between the circuits were reduced. Less likely to occur and excellent connection reliability.

It is process sectional drawing which shows typically the manufacturing method of the connection structure of the circuit member which concerns on one Embodiment of this invention. It is a schematic cross section which shows the behavior of the electroconductive particle at the time of using the conventional 1 layer film-form circuit connection material. It is a schematic cross section which shows the behavior of the electroconductive particle at the time of using the conventional two-layer film-form circuit connection material. It is a schematic cross section which shows the behavior of the electroconductive particle at the time of using the film-form circuit connection material of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Circuit connection material, 2 ... Circuit electrode, 3 ... LCD panel, 4 ... Circuit board, 5 ... Circuit board, 6 ... Circuit electrode, 7 ... Conductive particle, 8 ... Resist, 9 ... Resin, 15 ... Anisotropic conductive adhesion Agent layer, 16 ... insulating adhesive layer, 20 ... connection structure of circuit members.

Claims (7)

A circuit connecting material that is interposed between circuit electrodes facing each other, presses opposite circuit electrodes, and electrically connects the electrodes in the pressurizing direction,
It has a configuration in which an anisotropic conductive adhesive layer in which conductive particles are dispersed and an insulating adhesive layer are laminated,
A circuit connection material having a two-layer structure in which the average particle diameter a of the conductive particles and the thickness b of the anisotropic conductive adhesive layer satisfy the relationship of the following formula (1).
a ≧ b (1)   The circuit connection material according to claim 1, wherein an average particle diameter of the conductive particles is 2 to 6 μm.   The circuit connection material according to claim 1, wherein the anisotropic conductive adhesive layer has a thickness of 1 to 5 μm.   The circuit connection according to any one of claims 1 to 3, wherein the anisotropic conductive adhesive layer has a thickness of 20 to 100% with respect to an average particle diameter of the conductive particles. material.   The circuit connection material according to claim 1, wherein the conductive particles exist across the anisotropic conductive adhesive layer and the insulating adhesive layer.   The circuit connection material according to claim 1, wherein a minimum melt viscosity ratio of the anisotropic conductive adhesive layer to the insulating adhesive layer is at least 10 times or more. A first circuit member having a first connection terminal;
A second circuit member having a second connection terminal;
Arrange the first connection terminal and the second connection terminal to face each other,
The circuit connection material according to any one of claims 1 to 6 is interposed between the first connection terminal and the second connection terminal that are arranged to face each other, and the first connection terminal is heated and pressurized, and then the first connection terminal is disposed. A circuit member connection structure in which a connection terminal and the second connection terminal are electrically connected.

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