JP2016171133A - Film-like circuit connection material and method for manufacturing connection structural body of circuit member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a film-like circuit connection material capable of obtaining sufficient curing of a resin even in the case where a photo-curing resin is cured with light; and a method for manufacturing a connection structural body of a circuit member using the same.SOLUTION: There is disclosed a photo-curing type film-like circuit connection material 100 for bonding a first circuit member and a second circuit member. The film-like circuit connection material 100 includes an adhesive 20 and light reflecting particles 2 dispersed in the adhesive 20. The light reflecting particles 2 are distributed to be offset to one main surface 100a side of the film-like circuit connection material 100 in a thickness direction of the film-like circuit connection material.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a film-like circuit connecting material and a method for producing a circuit member connection structure.

  Conventionally, for example, an anisotropic conductive adhesive in which conductive particles are dispersed in an adhesive is used for connection between a substrate such as a liquid crystal display and a circuit member such as an IC chip or FPC (flexible printed wiring board). (For example, refer to Patent Documents 1 and 2). When the circuit member is mounted on the substrate, a method of directly connecting the electrodes face down has been adopted instead of the conventional wire bonding method. In such a connection method, the electrode of the circuit member and the electrode of the substrate are opposed to each other through the anisotropic conductive adhesive, and the anisotropic conductive adhesive is cured by heat while applying pressure to the circuit member and the substrate. Yes.

JP 2003-253217 A JP 2003-253239 A

  In recent years, with the demand for downsizing and thinning of electronic devices, the distance between electrodes and the width of electrodes of circuit members have become very small. Moreover, in order to cope with the improvement of the display quality of the liquid crystal, the thickness of the glass substrate tends to be reduced.

  In order to improve the display quality, it is necessary to suppress the warpage of the substrate after thermocompression bonding. However, in the connection (mounting) method using only heat, the temperature difference between the tool for crimping and the stage supporting the circuit member. Therefore, there has been a problem that warpage due to a difference in thermal expansion occurs.

  On the other hand, a connection (mounting) method for curing a photocurable resin with light has been proposed in recent years. However, since this method can use light and heat at the same time, only normal heat is used. Compared to the case, a lower temperature of the connection (mounting) process is expected. However, when a circuit or a terminal formed on a light-transmitting substrate such as glass is not a light-transmitting material, there is a problem that the curing of the photocurable resin is insufficient.

  The present invention has been made in view of the above circumstances, and is a film that can be cured sufficiently even when a circuit member having a light shielding portion is connected while being photocurable. An object of the present invention is to provide a method for manufacturing a connection structure for a circuit member and a circuit member connection structure using the same.

  The present invention provides a first circuit member having a first circuit board and a first circuit electrode having a first circuit electrode provided on the first circuit board, a second circuit board and the second circuit board. A photo-curing film for adhering the second circuit member having the second circuit electrode so that the first circuit electrode and the second circuit electrode are electrically connected to each other It relates to a circuit connection material. The film-like circuit connecting material includes an adhesive and light-reflective particles dispersed in the adhesive, and the light-reflecting particles are in the film direction in the thickness direction of the film-like circuit connecting material. It is distributed unevenly on one main surface side of the circuit connecting material.

  According to the film-like circuit connecting material according to the present invention, the light-reflective particles are unevenly distributed on one main surface side of the film-like circuit connecting material in the thickness direction of the film-like circuit connecting material. The light irradiated from the other main surface side where many reflective particles are not distributed is reflected (scattered) in the direction toward the inside of the circuit connecting material. Therefore, it is considered that light sufficiently reaches the light-shielding portion generated by the circuit or the like, and the film-like circuit connecting material can be cured well.

  The film-like circuit connecting material includes a light reflecting layer containing the light reflecting particles provided on the one main surface side, and a conductive particle layer containing conductive particles, and these are laminated in this order. It's okay.

  The film-like circuit connecting material may further include a non-conductive particle layer substantially free of conductive particles, and the non-conductive particle layer may be laminated between the light-reflecting particles and the conductive particle layer. Alternatively, the light reflecting layer, the conductive particle layer, and the nonconductive particle layer may be laminated in this order.

  The present invention also provides a first circuit member having a first circuit board and a first circuit electrode provided on the first circuit board, a second circuit board, and the second circuit board. The first circuit electrode and the second circuit electrode are opposed to each other while the film-like circuit connecting material is interposed between the second circuit member having the provided second circuit electrode. And curing the film-like circuit connecting material by a method comprising irradiating the film-like circuit connecting material with light and heating the film-like circuit connecting material, and the first circuit electrode. And a step of obtaining a connection structure bonded so that the second circuit electrode is electrically connected to the second circuit electrode.

  In the manufacturing method, the film-like circuit connecting material is arranged in a direction in which the one main surface is on the first circuit member side, and the light is applied to the film-like circuit connecting material from the second circuit board side. May be irradiated. In the manufacturing method, the first circuit member may be a semiconductor chip, and the second circuit board may be a light transmissive substrate.

  According to the film-like circuit connection material according to the present invention, the film-like circuit connection can be sufficiently cured even when a circuit member having a light shielding portion is connected while being photocurable. It becomes possible to provide the material. Moreover, it becomes possible to provide the manufacturing method of the connection structure of the circuit member which can ensure favorable conduction | electrical_connection rapidly by using such a film-form circuit connection material.

It is a schematic cross section which shows one Embodiment of a film-form circuit connection material. It is a series of process drawings which manufacture the connection structure of a circuit member. It is a schematic diagram of the process of FIG.2 (b). (A) is a schematic diagram which shows the board | substrate for evaluation in an Example. (B) is an enlarged schematic diagram of a circuit electrode (electrode pad).

  Hereinafter, preferred embodiments of the present invention will be described, but the present invention is not limited to these embodiments. In the present specification, “(meth) acrylate” means “acrylate” or “methacrylate” corresponding thereto. The same applies to similar expressions such as “(meth) acrylic acid”.

(Film-like circuit connection material)
The film-like circuit connecting material of the present embodiment includes a first circuit board, a first circuit member having a first circuit electrode provided on the first circuit board, a second circuit board, and the first circuit board. To bond a second circuit member having a second circuit electrode provided on a second circuit board so that the first circuit electrode and the second circuit electrode are electrically connected to each other. This is a photocurable film-like circuit connecting material.

  FIG. 1 is a schematic cross-sectional view showing an embodiment of a film-like circuit connecting material. A film-like circuit connecting material 100 in FIG. 1 includes an adhesive 20 and light-reflective particles 2 and conductive particles 4 dispersed in the adhesive 20. The film-like circuit connecting material 100 includes a light reflecting layer 10 containing the light reflecting particles 2, a conductive particle layer 30 containing the conductive particles 4, and a non-conductive particle layer 40 substantially not containing the conductive particles 4. Composed. Since the light reflective particles 2 are contained in the light reflective layer 10, the light reflective particles 2 are biased toward the one main surface 100 a side of the film-like circuit connection material 100 in the thickness direction of the film-like circuit connection material 100. Distributed. The adhesive 20 includes an adhesive 10 a included in the light reflecting layer 10, an adhesive 30 a included in the conductive particle layer 30, and an adhesive 40 a included in the non-conductive particle layer 40. The adhesive 10a, the adhesive 30a, and the adhesive 40a may be the same or different. In this specification, “adhesive” means a curable resin composition composed of components other than light-reflective particles and conductive particles in a circuit connecting material.

  The laminated configuration of the film-like circuit connecting material is not limited to the three-layer configuration in FIG. 1, and may be any configuration in which the light-reflective particles are unevenly distributed on one main surface side. For example, the non-conductive particle layer 40 may not be provided, or the light reflecting layer 10, the conductive particle layer 30, and the non-conductive particle layer 40 may be stacked in this order. Further, the film-like circuit connecting material may have a multilayer structure (not shown) having four or more layers.

  The light-reflective particles are distributed unevenly toward one main surface side of the film-like circuit connecting material in the thickness direction of the film-like circuit connecting material. More specifically, 90% by mass or more of the light-reflecting particles in the film circuit connecting material is within 75%, within 50%, within 30% of the thickness of the film-like circuit connecting material from one main surface side. It may be distributed within a range of 20%, 15% or 10%.

  The total thickness of the film-like circuit connecting material may be, for example, 2 μm to 50 μm. When the thickness of the film-like circuit connecting material is 2 μm or more, the film-like circuit connecting material tends to be sufficiently filled between the first circuit member and the second circuit member. When the thickness of the film-like circuit connecting material is 50 μm or less, electrical conduction between the first circuit member and the second circuit member tends to be sufficiently ensured.

  The thickness of the light reflecting layer may be 5 μm or less. Moreover, the thickness of the light reflection layer may be 0.2 μm to 3 μm or 0.5 μm to 2 μm. When the thickness of the light reflecting layer is 5 μm or less, sufficient curing of the light reflecting layer tends to be obtained. When the thickness of the light reflecting layer is 0.2 μm or more, the coating property is good.

  The adhesive 10a includes at least a photocurable resin and a photopolymerization initiator. Hereinafter, each component will be described.

  The photocurable resin is a resin having a property of being cured by light energy. Although it does not restrict | limit especially as a photocurable resin, For example, (meth) acrylic resin, an epoxy resin, an oxetane compound etc. are mentioned.

  Examples of the (meth) acrylic resin include photopolymerizable oligomers such as epoxy (meth) acrylate oligomers, urethane (meth) acrylate oligomers, polyether (meth) acrylate oligomers, and polyester (meth) acrylate oligomers. These may be used alone or in combination. Among these, a urethane acrylate oligomer may be used because it suppresses curing shrinkage and gives flexibility when the adhesive is cured.

  Since the viscosity of the photopolymerizable oligomer tends to be high, it may be used in combination with a photopolymerizable polyfunctional (meth) acrylate monomer having a viscosity lower than that of the photopolymerizable oligomer. Examples of the photopolymerizable polyfunctional (meth) acrylate monomer include trimethylolpropane tri (meth) acrylate, polyethylene glycol di (meth) acrylate, polyalkylene glycol di (meth) acrylate, pentaerythritol (meth) acrylate, and the like. These may be used alone or in combination.

  Examples of the epoxy resin include liquid or solid epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolac type epoxy resin, and alicyclic epoxy resin. Among these, an alicyclic epoxy resin may be used because it is possible to increase the curing rate when it is cured by irradiation with ultraviolet rays.

  Examples of oxetane compounds include xylylene oxetane, 3-ethyl-3- (hydroxymethyl) oxetane, 3-ethyl-3- (hexyloxymethyl) oxetane, 3-ethyl-3- (phenoxymethyl) oxetane bis {[ 1-ethyl (3-oxetanyl)] methyl} ether and the like.

  Examples of the photopolymerization initiator include a photo radical generator, a photo base generator, and a photo acid generator. By combining the photoradical generator with the above-mentioned (meth) acrylic resin, the (meth) acrylic resin can be photoradically polymerized. In addition, the photobase generator or the photoacid generator can be combined with the above-described epoxy resin or oxetane compound to cause the epoxy resin or oxetane compound to undergo photoanionic polymerization or photocationic polymerization.

  Examples of the photoradical generator include benzoin ethers such as benzoin ethyl ether and isopropyl benzoin ether, benzyl ketals such as benzyl and hydroxycyclohexyl phenyl ketone, ketones such as benzophenone and acetophenone and derivatives thereof, thioxanthones, and biimidazoles. It is done. Components that act as sensitizers such as amines, sulfur compounds, and phosphorus compounds may be added to these photoradical generators at an arbitrary ratio, if necessary. The photo radical generator can be appropriately selected according to the wavelength of the light source, desired curing characteristics, and the like.

  A photobase generator is a compound that rapidly generates one or more types of basic substances by changing the molecular structure upon irradiation with light such as ultraviolet rays or visible light, or by causing cleavage within the molecule. Examples of the basic substance here include primary amines, secondary amines, tertiary amines, and polyamines and derivatives thereof in which two or more of these amines are present in one molecule; imidazoles, Pyridines, morpholines and their derivatives. Moreover, you may use together the compound which generate | occur | produces two or more types of basic substances by light irradiation.

  As the photobase generator, a compound having an α-aminoacetophenone skeleton may be used. Since the compound having the skeleton has a benzoin ether bond in the molecule, it is easily cleaved within the molecule by light irradiation, and the generated substance acts as a basic substance. Specific examples of the compound having an α-aminoacetophenone skeleton include (4-morpholinobenzoyl) -1-benzyl-1-dimethylaminopropane (manufactured by Ciba Specialty Chemicals, trade name Irgacure 369, “Irgacure” is a registered trademark), Examples thereof include compounds such as 4- (methylthiobenzoyl) -1-methyl-1-morpholinoethane (manufactured by Ciba Specialty Chemicals, trade name Irgacure 907), and solutions thereof.

  Any known photoacid generator can be used as long as it is a compound that generates a cationic species upon irradiation with actinic rays containing a wavelength component of 180 nm to 750 nm. Specifically, complex compounds such as aromatic diazonium salts, aromatic sulfonium salts, aliphatic sulfonium salts, aromatic iodonium salts, onium salts such as phosphonium salts, pyridinium salts, and selenonium salts, metal arene complexes, and silanol / aluminum complexes. , Benzoin tosylate, o-nitrobenzyl tosylate and the like can be used. Of these, sulfonium salts such as aromatic sulfonium salts and aliphatic sulfonium salts, iodonium salts such as aromatic iodonium salts, and iron-arene complexes can be preferably used because of high generation efficiency of cationic species. When the photoacid generator is an onium salt, hexafluoroantimonate, hexafluorophosphonate, tetrafluoroborate, tetrakis (pentafluorophenyl) borate and the like are preferably used from the viewpoint of reactivity.

  In addition, as a photoacid generator, light irradiation or heating of a triarylsilyl peroxide derivative, an acylsilane derivative, an α-sulfonyloxyketone derivative, an α-hydroxymethylbenzoin derivative, a nitrobenzyl ester derivative, an α-sulfonylacetophenone derivative, etc. Compounds that generate organic acids can also be used. Specifically, from the viewpoint of acid generation efficiency during light irradiation or heating, Sun Apro Co., Ltd. CPI series, Asahi Denka Kogyo Co., Ltd. Adekaoptomer SP series, Asahi Denka Kogyo Co., Ltd. Adeka Opton CP series, Union Carbide The Cyracure UVI series manufactured by Chirasu and the IRGACURE series manufactured by Ciba Specialty Chemicals are preferably used. Furthermore, if necessary, known singlet sensitizers or triplet sensitizers typified by anthracene and thioxanthone derivatives can be used in combination.

  The compounding quantity of photocurable resin may be 70 mass parts-99.9 mass parts with respect to 100 mass parts of adhesive agents. The compounding quantity of a photoinitiator may be 0.01 mass part-30 mass parts with respect to 100 mass parts of adhesive agents. When the amount of the photopolymerization initiator is 0.01 parts by mass or more, curing is sufficient and the adhesive force tends to be improved. Further, when the amount of the photopolymerization initiator is 30 parts by mass or less, the photopolymerization initiator can suppress the bleeding to the surface, and the adhesive force tends to be improved.

  The adhesive may include a film forming resin. The resin for film formation is not particularly limited as long as it does not inhibit the function of the photocurable resin. For example, phenoxy resin, unsaturated polyester resin, saturated polyester resin, urethane resin, butadiene resin, polyimide resin, polyamide Examples thereof include resins and polyolefin resins. These may be used alone or in combination, but a phenoxy resin may be used from the viewpoint of connection reliability.

  The phenoxy resin can be obtained by reacting bisphenol A and epichlorohydrin. A commercially available product may be used as the phenoxy resin. Moreover, a compounding quantity can be suitably adjusted according to the objective.

  The adhesive may include a silane coupling agent. Although it does not restrict | limit especially as a silane coupling agent, Epoxy type, an acrylic type, a thiol type, an amine type, etc. can be suitably selected according to the objective. Moreover, a compounding quantity can be suitably selected according to the objective.

  The adhesive may include an inorganic filler. Examples of the inorganic filler include components other than the light reflective particles described later, and examples thereof include silica. Specific examples include phenyl group-containing silane surface-treated spherical silica manufactured by Admatechs.

  The light-reflecting particles dispersed in the adhesive are not particularly limited as long as the particles reflect light, but can be appropriately selected. The light-reflecting particles may be particles whose surfaces are formed of at least one material selected from the group consisting of titanium oxide, titanite, zirconium titanate, zinc oxide, silver and aluminum. Examples of the shape of the light-reflecting particles include spherical particles, non-spherical particles such as scales, needles, and spindles. Specific examples include spherical titanium oxide particles (CR series) manufactured by Ishihara Sangyo Co., Ltd., zinc oxide particles (FZO series) manufactured by Ishihara Sangyo Co., Ltd., hollow spherical particles (SX series, XTP series) manufactured by JSR Corporation, Sakai Chemical Industry Co., Ltd. Examples include company-made spun titanium oxide particles (STR series), non-spherical titanium oxide particles (TTO series, FTL series) manufactured by Ishihara Sangyo Co., Ltd., and zinc oxide particles (FINEX series) manufactured by Sakai Chemical Industry Co., Ltd. Moreover, you may use a light reflective particle individually or in mixture of 2 or more types as needed.

  The compounding amount of the light reflecting particles may be 20 parts by volume, 25 parts by volume, or 30 parts by volume with respect to 100 parts by volume of the adhesive in the light reflecting layer. When the amount of the light-reflecting particles is 20 parts by volume or more, when the light-reflecting layer is formed, the light-reflecting particles can be uniformly present in the surface direction. The upper limit of the blending amount of the conductive particles may be 120 parts by volume or less, for example. When the blending amount of the light reflective particles is 120 parts by volume or less, streaky coating unevenness at the time of coating can be suppressed.

  The particle diameter of the light-reflecting particles may be 60% or less or 50% or less of the particle diameter of conductive particles described later. In addition, an average particle diameter will show the average value of the diameter of particle | grains if it is a spherical particle, and will show the average value of the longest part (major axis) of a particle | grain if it is a non-spherical particle. Moreover, the average particle diameter measured the diameter or long diameter of 100 particle | grains using the scanning electron microscope (SEM), and computed the average value.

  The film-like circuit connecting material according to the present embodiment includes a light reflecting layer containing the light reflecting particles provided on the one main surface side, and a conductive particle layer containing conductive particles. They may be stacked in this order.

  The conductive particle layer 30 contains an adhesive 30a having the same or different composition as the above-described adhesive 10a, and the conductive particles 4 dispersed in the adhesive 30a.

  As the conductive particles 4, particles made of only metal or those obtained by forming a metal layer on the surface of organic or inorganic core particles can be used. Of these, those obtained by forming a metal layer on the surface of the organic core particles may be used. The method for forming the metal layer is not particularly limited, and examples thereof include sputtering and plating, and plating may be used from the viewpoint of simplicity. The thickness of the metal layer may be 10 nm or more or 30 nm or more.

  The organic core particle is not particularly limited, and examples thereof include acrylic resins such as polymethyl methacrylate and polymethyl acrylate, and polyolefin resins such as polyethylene, polypropylene, polyisobutylene, and polybutadiene.

  The metal of the metal layer formed by plating or the like is not particularly limited, but metal such as gold, silver, copper, platinum, zinc, iron, palladium, nickel, tin, chromium, titanium, aluminum, cobalt, germanium, cadmium, ITO And metal compounds such as solder. From the viewpoint of corrosion resistance, nickel, palladium, and gold may be used.

  The metal layer may have a single layer structure or a laminated structure including a plurality of layers. In the case of a single layer structure, the metal layer may be nickel from the viewpoint of cost, conductivity, and corrosion resistance. Furthermore, considering the recent flattening of the glass electrode, it may be nickel having protrusions on the surface. In the case of a laminated structure, a noble metal layer such as gold or palladium may be provided on the surface of the nickel layer.

  Insulating fine particles having a particle size of about 20 nm to 500 nm may adhere to the surface of the outermost layer of the conductive particles. The insulating fine particles may be either an organic compound or an inorganic oxide, or a mixture of both. The particle size of the insulating fine particles can be measured by the specific surface area conversion method by the BET method or the X-ray small angle scattering method. When the particle size is 20 nm or more, the insulating fine particles act as an insulating film, and there is a tendency that a short circuit between adjacent circuit electrodes can be suppressed. On the other hand, when the average particle size is 500 nm or less, sufficient conductivity between the opposing bump electrodes tends to be obtained.

  The compounding amount of the conductive particles may be 20 parts by volume or more, 25 parts by volume or more, or 30 parts by volume or more with respect to 100 parts by volume of the adhesive in the conductive particle layer. When the blending amount of the conductive particles is 20 parts by volume or more, a sufficient number of conductive particles can be interposed between the bump electrode and the circuit electrode. The upper limit of the blending amount of the conductive particles may be 120 parts by volume or less. The short circuit between adjacent circuit electrodes at the time of crimping | compression-bonding can be suppressed as the compounding quantity of electroconductive particle is 120 volume parts or less.

  The thickness of the conductive particle layer 30 may be 0.5 μm to 15 μm. When the thickness of the conductive particle layer 30 is within this range, good conduction tends to be obtained when the circuit member is mounted.

  The non-conductive particle layer 40 contains an adhesive 40a having the same or different composition as the adhesives 10a and 30a, and does not substantially contain conductive particles and light-reflecting particles. Here, “substantially does not contain” means that the blending amount of the conductive particles or light-reflecting particles is 5 parts by volume or less and 3 parts by volume with respect to 100 parts by volume of the adhesive in the non-conductive particle layer. It means that it may be below or 1 part by volume. The volume of the conductive particles in the non-conductive particle layer may be 0 part by volume.

  The thickness of the non-conductive particle layer 40 may be 0.5 μm to 15 μm. When the thickness of the non-conductive particle layer 40 is within this range, sufficient resin flow can be obtained, and good adhesiveness tends to be obtained.

  The film-like circuit connecting material 100 can be produced, for example, by separately producing the light reflecting layer 10, the conductive particle layer 30, and the non-conductive particle layer 40, and then bonding the respective layers. For example, each layer can be obtained by applying and drying the resin component of each layer on a release film formed of PET (polyethylene terephthalate) resin or the like. Next, the three-layer film-like circuit connection material 100 can be produced by bonding the layers using, for example, a hot roll laminator.

(Method for manufacturing circuit member connection structure)
Next, the manufacturing method of the connection structure of a circuit member is demonstrated. The method for manufacturing a circuit member connection structure according to the present embodiment includes a first circuit board, a first circuit member having a first circuit electrode provided on the first circuit board, and a second circuit. A second circuit member having a second circuit electrode provided on the substrate and the second circuit board, while interposing the film-like circuit connecting material therebetween, and the first circuit electrode and Disposing the film-like circuit connection material by a method comprising a step of arranging the second circuit electrodes to face each other, irradiating the film-like circuit connection material with light, and heating the film-like circuit connection material. Curing to obtain a connection structure bonded so that the first circuit electrode and the second circuit electrode are electrically connected to each other. The film-like circuit connecting material is arranged in such a direction that the one main surface is on the first circuit member side, and the film-like circuit connecting material is irradiated with the light from the second circuit board side. Good. 2A to 2C are a series of process diagrams for manufacturing a circuit member connection structure.

  First, a film-like circuit connecting material 100, a first circuit member 50 having a first circuit board 54 and a first circuit electrode 52 provided on the first circuit board 54, and a second circuit board 64 and a second circuit member 60 having a second circuit electrode 62 provided on the second circuit board 64 are prepared. Next, the first circuit member 50 and the second circuit member 60 are interposed between them so that one main surface 100a of the film-like circuit connecting material 100 is on the first circuit member 50 side. However, it arrange | positions so that the 1st circuit electrode 52 and the 2nd circuit electrode 62 may oppose (refer Fig.2 (a)). The film-like circuit connecting material 100 is easy to handle, and the film-like circuit connecting material 100 can be easily interposed between the first circuit member 50 and the second circuit member 60. Connection work between the electrode 52 and the second circuit electrode 62 can be easily performed.

  In the finally obtained connection structure (FIG. 2C), the distance between the circuit (also referred to as an electrode) of the first circuit member and the circuit (electrode) of the second circuit member is the diameter of the conductive particles. It is preferable that the circuits (electrodes) face each other so as to be 1.5 times or less. In this case, by applying pressure, the conductive particles are sufficiently captured between the circuit (electrode) of the first circuit member and the circuit (electrode) of the second circuit member, and good conduction can be realized.

  The first circuit member 50 may be a semiconductor chip such as an IC chip, an LSI chip, a resistor chip, or a capacitor chip, for example. For example, silicon or the like is used for the first circuit board 54. The surface of the first circuit electrode 52 is, for example, one or more selected from gold, silver, tin, ruthenium, rhodium, palladium, osmium, iridium, platinum, and indium tin oxide (ITO). May be configured. The first circuit electrode 52 may be more easily deformed than the conductive particles 4.

  The second circuit member 60 includes a second circuit board 64 and a second circuit electrode 62 provided on the second circuit board 64, and the second circuit board 64 is light-transmissive. It may be a substrate. The second circuit board 64 is not particularly limited as long as it is a light-transmitting substrate, but is not limited to glass substrate, polyimide substrate, polyethylene terephthalate substrate, polycarbonate substrate, polyethylene naphthalate substrate, glass reinforced epoxy substrate, paper phenol substrate, ceramic. A board | substrate, a laminated board, etc. are mentioned. Among these, a glass substrate, a polyethylene terephthalate substrate, a polycarbonate substrate, and a polyethylene naphthalate substrate may be used because of excellent transparency to ultraviolet rays. The second circuit electrode 62 can be the same as the first circuit electrode 52.

  Next, the film-like circuit connection material 100 is cured by a method including irradiating the film-like circuit connection material 100 with light and heating the film-like circuit connection material 100. At this time, the film-like circuit connecting material 100 is irradiated with light in the direction B from the second circuit board 64 side. Further, the film-like circuit connecting material 100 may be heated and further pressurized in the direction A (see FIG. 2B). Since the film-like circuit connecting material 100 includes the light-reflective particles 2, the light transmitted through the second circuit member 60 is reflected (scattered) by the light-reflective particles 2, and the light reaches the light-shielding portion. Is possible. Therefore, when light irradiation and heating are performed, the curing reaction of the adhesive 20 easily proceeds.

  FIG. 3 is a schematic diagram of the process of FIG. First, a support stage 90 having a light transmission part 92 is prepared. Next, the second circuit member 60 is disposed on the light transmission portion 92, and the film-like circuit connection material 100 and the first circuit member 50 are disposed on the second circuit member 60. By irradiating light in the direction B from the light irradiation member 80, the light transmitted through the light transmission part 92 and the second circuit member 60 is irradiated onto the film-like circuit connection material 100. On the other hand, the film-like circuit connecting material 100 is heated by the heating and pressing member 82 and further pressurized in the direction A.

  The type of light used for light irradiation is not particularly limited, but may be ultraviolet rays because the resin component is easily cured. The wavelength of the ultraviolet light is not particularly limited, but may be 200 nm to 400 nm or 300 nm to 400 nm. The light source for light irradiation is not particularly limited, and an LED lamp, a YAG laser, a xenon lamp, a halogen lamp, a high-pressure mercury lamp, and the like can be appropriately selected according to the target wavelength.

  Either the irradiation of the film-like circuit connection material 100 with light or the heating of the film-like circuit connection material 100 may be performed first, but the film-like circuit connection material 100 may be heated before the light irradiation. Moreover, you may pressurize simultaneously with a heating. By first heating or pressurizing, the film-like circuit connecting material 100 can be cured after sufficiently flowing, so that it is possible to obtain a circuit member connection structure that secures conduction quickly and satisfactorily. it can.

  Heating and pressurization can be performed using the heating pressing member 82. Examples of the heating and pressing member 82 include a heat tool. The heating temperature is not particularly limited, but may be 30 ° C to 120 ° C or 50 ° C to 100 ° C. The pressure at the time of pressurization is not particularly limited, but may be 0.1 MPa to 100 MPa. The time for heating and pressurization is not particularly limited, but may be 0.5 seconds to 100 seconds.

  Alternatively, the film-like circuit connecting material 100 may be irradiated with light after 0.5 seconds or more or 1.0 seconds or more have passed since heating or pressurization.

  Further, the support stage 90 may be preheated when heating and pressurizing. The heating temperature is not particularly limited, but may be 25 to 120 ° C. The light transmitting portion 92 is not particularly limited as long as it has light transparency, and examples thereof include polycarbonate, quartz, quartz glass, and ceramic. From the viewpoint of heat resistance and transparency, quartz glass may be used.

  The first circuit electrode 52 includes the first circuit member 50, the second circuit member 60, and the cured product 70 of the film-like circuit connection material by the method for manufacturing the circuit member connection structure. Thus, a circuit member connection structure 200 can be obtained that is bonded so that the second circuit electrode 62 and the second circuit electrode 62 are electrically connected (see FIG. 2C).

  Hereinafter, the contents of the present invention will be described in more detail using examples and comparative examples. However, the present invention is not limited to the following examples.

Example 1
As an epoxy compound, 1.0 g of an alicyclic epoxy resin (manufactured by Daicel Corporation, Celoxide 2021P, product name) and 0.5 g of a bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Corporation, jER1010, trade name), as a photocation generator 0.06 g of sulfonium salt (manufactured by BASF, Irgacure 290), 1.5 g of phenoxy resin as a film-forming resin, 0.3 g of silica particles as an inorganic filler (manufactured by Admatechs, phenyl group-containing silane surface-treated spherical silica, average particle diameter These were dissolved or dispersed in a solvent to prepare a varnish. Next, conductive particles having a nickel layer on the surface of particles having PMMA (polymethyl methacrylate) as a core were prepared as conductive particles. A protrusion was previously formed on the surface of the nickel layer of the conductive particles. The conductive particles were mixed and dispersed in the varnish so that the volume other than the solvent of the varnish was 100 parts by volume, and a mixed varnish was prepared. The mixed varnish was applied to a fluororesin film having a thickness of 50 μm using a coating apparatus, and a conductive particle layer containing conductive particles having a thickness of 5 μm was obtained by drying with hot air at 70 ° C. for 5 minutes. The conductive particle layer did not contain light reflective particles.

  Epoxy compound as an alicyclic epoxy resin 1.5 g (manufactured by Daicel Corporation, Celoxide 2021P, product name), photocation cation generator 0.06 g as a cation generator (BASF Corp., Irgacure 290), and phenoxy resin 1 as a film-forming resin 0.5 g, 0.7 g of silica particles (manufactured by Admatechs, phenyl group-containing silane surface-treated spherical silica, average particle size 0.050 μm) as an inorganic filler, and these are dissolved or dispersed in a solvent to obtain a mixed varnish. Produced. The mixed varnish was applied to a fluororesin film having a thickness of 50 μm using a coating apparatus, and a nonconductive particle layer containing no conductive particles having a thickness of 14 μm was obtained by hot air drying at 70 ° C. for 5 minutes. In addition, the light-reflective particle was not mix | blended with the nonelectroconductive particle layer.

  A varnish similar to the conductive particle layer was produced. Without mixing and dispersing conductive particles in the above varnish, titanium oxide (Ishihara Sangyo Co., Ltd. CR-50, average particle diameter of 0.25 μm) is mixed and dispersed so as to be 40% by volume as light reflecting particles. A varnish was prepared. The film was applied to a fluororesin film having a thickness of 50 μm using a coating apparatus, and a light reflecting layer having a thickness of 1 μm including light reflecting particles was obtained by hot air drying at 70 ° C. for 5 minutes.

  The obtained conductive particle layer, non-conductive particle layer, and light reflection layer were laminated in this order, and bonded together through a laminator while heating to 50 ° C. By sandwiching this with a fluororesin film, a film-like circuit connecting material (i) having a three-layer structure of conductive particle layer / non-conductive particle layer / light reflecting layer was obtained. In the film-like circuit connecting material (i), from the thickness of the conductive particle layer, the non-conductive particle layer, and the light reflecting layer, the light reflecting particles (titanium oxide) have the thickness of the film-like circuit connecting material from one main surface side. It can be seen that the distribution is biased within a range of 5% or less.

Example 2
The nonconductive particle layer, the conductive particle layer, and the light reflection layer of Example 1 were laminated in this order, and were bonded together through a laminator while heating to 50 ° C. By sandwiching this with a fluororesin film, a film-like circuit connecting material (ii) having a three-layer structure of non-conductive particle layer / conductive particle layer / light reflecting layer was obtained. In the film-like circuit connecting material (ii), from the thickness of the conductive particle layer, the non-conductive particle layer, and the light reflecting layer, the light reflecting particles (titanium oxide) have the thickness of the film-like circuit connecting material from one main surface side. It was found that the distribution was unevenly distributed within a range of 5% or less.

Example 3
Without attaching the light reflecting layer, light reflecting particles were further added and dispersed in the same composition as the non-conductive particle layer of Example 1 to produce a light reflecting layer having a thickness of 14 μm. This and the same conductive particle layer as in Example 1 were bonded together in the same manner as in Example 1 to prepare a film-like circuit connecting material (iii) having a two-layer structure of light reflecting layer / conductive particle layer. In the film-like circuit connecting material (iii), the thickness of the light-reflecting particle (titanium oxide) is within 74% of the thickness of the film-like circuit connecting material from one main surface side, based on the thickness of the light reflecting layer and the conductive particle layer. It can be seen that the distribution is biased.

Comparative Example 1
A film-like circuit connecting material (iv) having a two-layer structure of conductive particle layer / non-conductive particle layer is obtained by sandwiching between fluororesin films in the same manner as in Example 1 except that the light reflecting layer is not bonded. It was.

(Evaluation method)
FIG. 4 is a schematic view showing an evaluation substrate. The evaluation board corresponds to the second circuit member 60 having the second circuit electrode 62 on the second circuit board 64. 4 is a pattern in which a glass substrate as the second circuit board 64, a metal pad having a size of 2 × 3 mm, and a metal wiring having a width of 0.5 mm connected to the metal pad are repeatedly arranged (second circuit). Electrode).

  The film-like circuit connection materials (i) to (iv) were cut out and pasted in a size of 5 × 25 mm as shown in a of FIG. The evaluation substrate (1) is obtained by using a film-like circuit connecting material (i) and attaching the conductive particle layer side to the wiring (circuit) surface of the substrate. The evaluation substrate (2) is obtained by using the film-like circuit connecting material (ii) and attaching the nonconductive particle layer side to the wiring (circuit) surface of the substrate. The evaluation substrate (3) is obtained by using a film-like circuit connecting material (iii) and attaching the light reflection layer side to the wiring (circuit) surface of the substrate. The evaluation substrate (4) is obtained by using the film-like circuit connecting material (iv) and attaching the conductive particle layer side to the wiring (circuit) surface of the substrate.

  The evaluation substrates (1) to (4) were heated and pressurized at 100 ° C. for 5 seconds from the top of the fluororesin film using a thermocompression bonding apparatus (manufactured by Shibaura Mechatronics Co., Ltd.), and at the same time, 500 mJ from the glass substrate side. Irradiation with ultraviolet rays (125 mW × 4 s) was performed.

  The metal pads of the evaluation substrates (1) to (4) and the film-like circuit connecting materials (i) to (iv) on the metal wirings are in a state where light irradiated from the glass substrate side is not directly applied (light shielding). . Therefore, it was confirmed whether the reactivity of the light-shielding portion was improved by measuring the reaction rate of the cured product (epoxy conversion rate) at the center of the metal pad.

  The reactivity of the light-shielding part is determined by FT-IR (the center part of the light-shielding part (c in FIG. 4B) in b of FIG. 4A of the cured product of the film-like circuit connecting materials (i) to (iv). Epoxy conversion was determined by measurement using BIO-RAD. The epoxy conversion rate is measured three times and shows the average value. Table 1 shows the epoxy conversion.

  From the measurement result of FT-IR, the average epoxy conversion of the evaluation substrate (4) was 8.9%, whereas the average epoxy conversion of the evaluation substrate (1) was 35.5%. The average epoxy conversion of the substrate (2) for use was 46.7%, and the average epoxy conversion of the substrate for evaluation (3) was 17.9%.

  2 ... light reflective particles, 4 ... conductive particles, 10 ... light reflective layer, 20, 10a, 30a, 40a ... adhesive, 30 ... conductive particle layer, 40 ... non-conductive particle layer, 50 ... first circuit member, 52 ... 1st circuit electrode, 54 ... 1st circuit board, 60 ... 2nd circuit member, 62 ... 2nd circuit electrode, 64 ... 2nd circuit board, 70 ... Hardened | cured material of film-form circuit connection material DESCRIPTION OF SYMBOLS 80 ... Light irradiation member, 82 ... Heat press member, 90 ... Support stage, 92 ... Light transmission part, 100 ... Film-like circuit connection material, 100a ... Main surface, 200 ... Connection structure of circuit member.

Claims (7)

A first circuit member having a first circuit board and a first circuit electrode provided on the first circuit board; a second circuit board and a second circuit board provided on the second circuit board; A photo-curing type film-like circuit connection material for adhering a second circuit member having the circuit electrode to the first circuit electrode and the second circuit electrode so as to be electrically connected to each other. There,
The film-like circuit connecting material includes an adhesive and light-reflective particles dispersed in the adhesive,
The film-like circuit connection material in which the light-reflecting particles are distributed in a biased manner toward one main surface of the film-like circuit connection material in the thickness direction of the film-like circuit connection material.   The film-like circuit connecting material includes a light reflecting layer containing the light reflecting particles provided on the one main surface side, and a conductive particle layer containing conductive particles, and these are laminated in this order. The film-like circuit connecting material according to claim 1.   The film-like circuit connecting material further comprises a non-conductive particle layer substantially free of conductive particles, and the non-conductive particle layer is laminated between the light-reflecting particles and the conductive particle layer. 2. The film-like circuit connecting material according to 2.   The film-like circuit connecting material further includes a non-conductive particle layer substantially free of conductive particles, and the light reflecting layer, the conductive particle layer, and the non-conductive particle layer are laminated in this order. The film-like circuit connecting material according to 1. A first circuit member having a first circuit board and a first circuit electrode provided on the first circuit board; a second circuit board and a second circuit board provided on the second circuit board; The first circuit electrode and the second circuit member with the second circuit member having the circuit electrode of the first circuit electrode and the second circuit member interposed therebetween with the film-like circuit connecting material according to any one of claims 1 to 4 interposed therebetween. Arranging the circuit electrodes so that they face each other,
Curing the film-like circuit connecting material by a method comprising irradiating the film-like circuit connecting material with light and heating the film-like circuit connecting material, and the first circuit electrode and the second circuit And a step of obtaining a connection structure bonded so that the electrodes are electrically connected to each other. The film-like circuit connecting material is arranged in a direction in which the one main surface is on the first circuit member side,
The manufacturing method according to claim 5, wherein the film-like circuit connection material is irradiated with the light from the second circuit board side.   The manufacturing method according to claim 5 or 6, wherein the first circuit member is a semiconductor chip and the second circuit board is a light-transmitting substrate.

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