Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J7/00—Adhesives in the form of films or foils
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K3/00—Apparatus or processes for manufacturing printed circuits
  • H05K3/30—Assembling printed circuits with electric components, e.g. with resistor
  • H05K3/32—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits
  • H05K3/321—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by conductive adhesives
  • H05K3/323—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by conductive adhesives by applying an anisotropic conductive adhesive layer over an array of pads
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B5/00—Non-insulated conductors or conductive bodies characterised by their form
  • H01B5/14—Non-insulated conductors or conductive bodies characterised by their form comprising conductive layers or films on insulating-supports
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
  • H01R4/00—Electrically-conductive connections between two or more conductive members in direct contact, i.e. touching one another; Means for effecting or maintaining such contact; Electrically-conductive connections having two or more spaced connecting locations for conductors and using contact members penetrating insulation
  • H01R4/04—Electrically-conductive connections between two or more conductive members in direct contact, i.e. touching one another; Means for effecting or maintaining such contact; Electrically-conductive connections having two or more spaced connecting locations for conductors and using contact members penetrating insulation using electrically conductive adhesives
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
  • H05K2201/10—Details of components or other objects attached to or integrated in a printed circuit board
  • H05K2201/10227—Other objects, e.g. metallic pieces
  • H05K2201/10378—Interposers
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
  • H05K2203/01—Tools for processing; Objects used during processing
  • H05K2203/0191—Using tape or non-metallic foil in a process, e.g. during filling of a hole with conductive paste
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
  • H05K2203/02—Details related to mechanical or acoustic processing, e.g. drilling, punching, cutting, using ultrasound
  • H05K2203/0271—Mechanical force other than pressure, e.g. shearing or pulling
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/25—Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/25—Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
  • Y10T428/254—Polymeric or resinous material
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/25—Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
  • Y10T428/256—Heavy metal or aluminum or compound thereof

Definitions

• the present invention relates to an anisotropic conductive adhesive sheet that has excellent microcircuit connecting properties, and a connecting structure
• the anisotropic conductive adhesive sheet disclosed in Patent Document 7 is based on a technical idea to secure electrical conductivity by sandwiching conductive particles between terminals themselves and at the same time to secure insulating properties by fixing conductive particles, the particle diameter of conductive particles distance between adjacent conductive particles and the film thickness of the anisotropic conductive adhesive sheet must be of substantially the same values.
• Patent Document 1 JP-A-6-349339
• Patent Document 2 JP Patent No. 2895872
• Patent Document 3 JP Patent No. 2062735
• Patent Document 4 JP-A-6-45024
• Patent Document 5 JP Patent No. 3165477
• Patent Document 6 JP-A-2002-519473
• Patent Document 7 JP-A-2-117980
• the present inventors have found that the problems can be solved by the use of an anisotropic conductive adhesive sheet characterized in that conductive particles having a certain average particle size are present in a certain range without contact with at least a certain proportion of conductive particles.
• the present invention provides the followings..
• An anisotropic conductive adhesive sheet comprising at least a curing agent, a curable insulating resin and conductive particles, wherein 90% or more of the conductive particles are present in a region of a thickness of not greater than 2.0 times the average particle size of the conductive particles extending from one surface of the anisotropic conductive adhesive sheet in the thickness direction, and 90% or more of the conductive particles are present without contact with other conductive particles, wherein the average particle size of the conductive particles is 1 to 8 ⁇ m, and the average particle distance between adjacent conductive particles is at least once but five times or less the average particle size and not greater than 20 ⁇ m, and wherein the thickness of the anisotropic conductive adhesive sheet is at least 1.5 times the average particle distance but not greater than 40 ⁇ m.
• conductive particles are at least those selected from the group consisting or noble metal-coated resin particles, noble metal-coated metal particles, metal particles, noble metal-coated alloy particles, and alloy particles
• a method for manufacturing an anisotropic conductive adhesive sheet comprising providing an adhesive layer on a biaxially stretchable film to form a laminate, densely packing conductive particles having an average particle size of 1 to 8 ⁇ m on the laminate to form a conductive particle-attached film, biaxially stretching and holding the conductive particle-attached film so that the average particle distance between adjacent conductive particles is at least once (1) but five (5) times or less the average particle size of the conductive particles and not greater than 20 ⁇ m, and transferring the conductive particles to an adhesive sheet containing at least a curing agent and a curable insulating resin and having a thickness of at least 1.5 times the average particle distance between the conductive particles but not greater than 40 ⁇ m.
• a method for electrically connecting an electronic circuit component having fine connecting terminals to a circuit board having a circuit corresponding thereto using an anisotropic conductive adhesive sheet comprising electrically connecting the electronic circuit component to the circuit board having a circuit corresponding thereto using the anisotropic conductive adhesive sheet according to (1) or (2), wherein said electronic circuit component has a height of the fine connecting terminals of 3 to 15 times the average particle distance between conductive particles and not greater than 40 ⁇ m, a distance between the fine connecting terminals of 1 to 10 times the average particle distance and not greater than 40 ⁇ m, and a pitch of the fine connecting terminals of 3 to 30 times the average particle distance and not greater than 80 ⁇ Am.
• the anisotropic conductive adhesive and connecting structure of the present invention have favorable insulating characteristics between adjacent circuits, and have favorable electrical connecting properties between coupled circuits.
• the present invention also exerts the above-described effect particularly in the connecting of microcircuits
• conductive particles in the present invention will be described.
• conductive particles although heretofore known conductive particles can be used, it is preferable to use at least those selected from the group consisting of noble metal-coated resin particles, noble metal-coated metal particles, metal particles, noble metal-coated alloy particles, and alloy particles. More preferably, these particles have melting points not higher than 500° C.
• the noble metal-coated resin particles the use of spherical particles of polystyrene, benzoguanamine, polymethyl methacrylate or the like coated with nickel and gold in this order is preferable.
• the use of particles of a metal, such as nickel and copper, coated with a noble metal, such as gold, palladium and rhodium, on the outermost layer is preferable; and as the noble metal-coated alloy particles, the use of alloy particles described below coated with a noble metal, such as gold, palladium and rhodium, on the outermost layer is preferable.
• coating methods thin-film forming methods such as vapor deposition and sputtering, coating methods by dry blending, or wet processes such as electroless plating and electrolytic plating, can be used. In view of mass productivity, an electroless plating method is preferable.
• metal particles and alloy particles the use of one or two or more selected from the group consisting of metals, such as silver, copper and nickel is preferable.
• alloy particles the use of low-melting-point alloy particles having a melting point of 500° C. or below is preferable, and furthermore, the use of low-melting-point alloy particles having a melting point of 350° C. or below is more preferable because metallic bond can be formed between connecting terminals and from the viewpoint of connecting reliability.
• flux a fatty acid or the like, such as abietic acid, can be used.
• the ratio of the average particle size to the maximum particle diameter of the conductive particles is preferably 2 or less and more preferably 1.5 or less. It is preferable that the particle size distribution of the conductive particles is narrower, and the geometric standard deviation of the particle size distribution of the conductive particles is preferably 1.2 to 2.5 and more preferably 1.2 to 1.4. If the geometric standard deviation is within the above-described values, the variation of the particle diameters is reduced. Normally, when a constant gap is present between two terminals to be connected, it is considered that the more even the particle diameters, the more effectively conductive particles function.
• the geometric standard deviation of particle size distribution means the value obtained by dividing the ⁇ value of the particle size distribution (the particle diameter value at 84.13% accumulation) by the particle diameter value at 50% accumulation.
• the cumulative value means the ratio of the number of particles having a certain particle diameter and smaller to the total number of particles expressed in percentage
• the sharpness of particle size distribution is expressed by the ratio of ⁇ (the particle diameter value at 84.13% accumulation) to the average particle size (the particle diameter value at 50% accumulation).
• the ⁇ value is a reading value from an actual measured value or a plotted value in the above graph.
• the average particle size and particle size distribution can be measured using heretofore known methods and instruments, and for the measurements, a wet particle size distribution meter, laser particle size distribution meter, or the like can be used. Alternatively, the particles can be observed using an electron microscope or the like and the average particle size and particle size distribution can be calculated.
• the average particle size and particle size distribution in the present invention can be obtained using a laser particle size distribution meter.
• the average particle size of the conductive particles is 1 to 8 ⁇ n, preferably 2 to 6 ⁇ m. In view of insulation properties, 8 ⁇ m or less is preferable, and the effect of variation in the height of connecting terminals or the like is insignificant; and in view of electrical connecting, 1 ⁇ m of more is preferable.
• the average particle distance to adjacent conductive particles is not greater than 20 ⁇ m and at least once to five times, preferably at least 1.5 to 3 times the average particle size. In view of preventing particle coagulation due to particle flow in connecting and securing insulation properties, not less than once the average particle size is preferable; and in view of fine connecting, not greater than five times is preferable.
• adjacent conductive particles mean 6 particles closest to an optionally selected conductive particle.
• the method for measuring the average particle distance to the adjacent conductive particles is as follows.
• a photo enlarged by an optical microscope is taken, optional 20 particles are selected, distances to 6 particles closest to each particle are measured, and the average value of the total is obtained to make it the average particle distance.
• the thickness of the anisotropic conductive adhesive sheet is at least 1.5 times the average particle distance but not greater than 40 ⁇ m and preferably at least twice the average particle distance but not greater than 40 ⁇ m. In view of mechanical connecting strength, not less than 1.5 times is preferable; and in view of preventing decrease in the number of coupled particles due to particle flow in connecting, not greater than 40 ⁇ m is preferable.
• the compounding quantity of conductive particles is preferably 0.5 parts by mass to 20 parts by mass relative to 100 parts by mass, more preferably 1 part by mass to 10 parts by mass of the components containing a curing agent and a curable insulating resin. In view of insulating properties, not greater than 20 parts by mass is preferable; and in view of electrical connecting properties, not less than 0.5 parts by mass is preferable.
• the anisotropic conductive adhesive sheet of the present invention will be described.
• 90% or more of the conductive particles are present in a region of a thickness of not greater than 2.0 times the average particle size of the conductive particles extending from one surface of the anisotropic conductive adhesive sheet in the thickness direction; however, it is preferable that 90% or more of them are present in a region of 1.5 times, it is more preferable that 95% or more of them are present in a region of 2.0 times, and it is further preferable that 95% or more of them are present in a region of 1.5 times.
• the average particle size is 3.0 ⁇ m
• “in a region of 2.0 times” means in a region of a thickness of 6.0 ⁇ m in the anisotropic conductive composition, and “90% or more of them are present in the region” means that 90% or more of the conductive particles are present in the layer of the thickness of 6.0 ⁇ m.
• the anisotropic conductive adhesive sheet of the present invention as the position where the conductive particles are present to the thickness direction of the anisotropic conductive adhesive sheet, the values of the positions of randomly selected 100 conductive particles measured using a laser microscope or the like that can measure the displacement of the Local direction are used.
• the number of conductive particles present without contact with other conductive particles can also be measured.
• the resolution of displacement measurement is preferably 0.1 ⁇ m or less, and more preferably 0.01 ⁇ m or less.
• the average particle size of the conductive particles the value previously measured separately using a laser particle size distribution meter or the like is used.
• the thickness of the anisotropic conductive adhesive sheet of the present invention is preferably 3 to 20 times, more preferably 5 to 10 times the average particle size of the conductive particles. From the aspect of adhesion strength of the connecting structure, not less than 3 times is preferable; and from the aspect of connecting properties, less than 20 times is preferable.
• the region of not more than 2.0 times the average particle size of the conductive particles where 90% or more conductive particles are present is preferably outside the center portion in the thickness direction of the conductive adhesive sheet, and more preferably, a part of the conductive particles are exposed on the surface of the anisotropic conductive adhesive sheet.
• the region of not greater than 2.0 times the average particle size of the conductive particles is preferably within 1 ⁇ 2, more preferably 1 ⁇ 3 the thickness of the sheet in the thickness direction form the surface of the conductive sheet. It is also preferable that a part of the conductive particles are exposed on the surface of the anisotropic conductive adhesive sheet.
• conductive particles in the present invention are present without contact with other conductive particles.
• conductive particles are present without contact with other conductive particles” means that each of the conductive particles is present alone without coagulation.
• the expression “present alone” or “single particle” may be used for this meaning.
• a method is preferable wherein a single layer of conductive particles are arranged on a stretchable film or sheet, the conductive particles are dispersed and arrayed by stretching it, and they are transferred onto an adhesive sheet composed of at least a curing agent and a curable insulating resin while maintaining the stretched state.
• the stretchable film although a known resin film or the like can be used, the use of a homopolymer or copolymer of polyethylene resin, polypropylene resin, polyester resin, polyvinyl alcohol resin, polyvinylbutyral resin, polyvinylidene chloride resin or the like, or a flexible and stretchable film of a resin such as nitryl rubber, butadiene rubber, silicone rubber is preferable. Polypropylene resin and polyester resin are particularly preferable.
• the shrinking percentage after stretching is preferably 10% or less, and more preferably 5% or less.
• a known method can be used as a method for dispersing, arranging and fixing conductive particles on a stretchable film.
• a method wherein an adhesive layer containing at least a thermoplastic resin is formed on the stretchable film, conductive particles are contacted and deposited thereon, and they are arranged in a single layer by applying load using a rubber roll can be adopted In this case, to pack the conductive particles without gaps, repetition of deposition and rolling steps for several times is preferable Since closest packing is the most stable structure in the case of spherical conductive particles, the conductive particles can be relatively easily packed
• the use of biaxial stretching equipment is preferable.
• the percentage of stretching is preferably 80% or more and 400% or less, more preferably 100% or more and 300% or less. Stretching by 100% means that the length of the portion stretched along the stretching direction is 100% the length of the film before stretching.
• the stretching direction is optional, biaxial stretching of a stretching angle of 90° is preferable, and simultaneous stretching is preferable.
• the stretching direction is optional, biaxial stretching of a stretching angle of 90° is preferable, and simultaneous stretching is preferable.
• the percentage of stretching in each direction can be either same or different As the biaxial stretching equipment, simultaneous biaxial continuous stretching equipment is preferable.
• a tenter-type stretching machine wherein long sides are fixed by chuck fittings, and the distances between them are simultaneously stretched in length and width directions to conduct continuous stretching is preferable.
• a screw system or a pantograph system can be used, in view of the adjustment accuracy, the pantograph system is more preferable.
• an anisotropic conductive adhesive sheet from the state wherein the conductive particles are dispersed and arranged by arranging a single layer of conductive particles on a stretchable film and stretching them
• a method wherein a solution containing at least an insulating resin is applied in the dispersed and arranged state, and dried, then the anisotropic conductive adhesive sheet is peeled off the stretchable sheet or the like, can be used.
• the anisotropic conductive adhesive sheet of the present invention can be a single-layer sheet or a laminate sheet wherein an adhesive sheet not containing conductive particles but containing at least an insulating resin is stacked.
• the film thickness of the adhesive sheet to be stacked is preferably thinner than the film thickness of the adhesive sheet containing conductive particles.
• thermosetting resin As the curable insulating resin used in the present invention, a thermosetting resin, a photo-curable resin, a thermosetting and photocurable resin, and an electron beam-curable resin can be used.
• a thermosetting insulating resin is preferable.
• epoxy resin, acrylic resin and the like can be used as the thermosetting resin, epoxy resin is particularly preferable.
• the epoxy resin is a compound having 2 or more epoxy groups in the molecule, and a compound having a glycidylether group, a glycidylester group, or an alicyclic epoxy group, and a compound wherein a double bond in the molecule is epoxidized are preferable.
• bisphenol-A-type epoxy resin, bisphenol-F-type epoxy resin, naphthalene-type epoxy resin, novolak-phenol-type epoxy resin, or modified epoxy resin thereof can be used.
• the curing agent used in the present invention can by any curing agent that can cure the above-described thermosetting insulating resins.
• a thermosetting resin is used as the curable insulating resin
• the agent that reacts with the thermosetting resin at 100° C. or above to cure it is preferable.
• a latent curing agent is preferable, and for example, an imidazole curing agent, a capsule-type imidazole curing agent, a cationic curing agent, a radical curing agent, a Lewis acid curing agent, an amine imide curing agent, a polyamine salt curing agent, a hydrazide curing agent, or the like can be used. From the aspects of storage properties and low-temperature reactivity, the capsule-type imidazole curing agent is preferable.
• thermoplastic resin a thermoplastic resin or the like can be compounded.
• a sheet By compounding a thermoplastic resin, a sheet can be easily formed.
• the compounding quantity in this time is preferably 200% by mass, more preferably 100% by mass of the combined components of the curing agent and curable insulating resin.
• the thermoplastic resin that can be compounded in the present invention is phenoxy resin, polyvinyl acetal resin, polyvinyl butyral resin, alkylated cellulose resin, polyester resin, acrylic resin, styrene resin, urethane resin, polyethylene terephthalate resin, and the like.
• Such resins can be selectively used alone or in a combination of two or more.
• a resin having a polar group, such as hydroxyl and carboxyl groups is preferable from the aspect of adhesive strength.
• the thermoplastic resin contains one or more thermoplastic resin having a glass transition temperature of 80° C. or above.
• additives can be compounded to the above-described components
• a connecting agent can be compounded as an additive.
• the connecting agent although a silane connecting agent, titanium connecting agent, or aluminum connecting agent can be used, the silane connecting agent is preferable.
• silane connecting agent ⁇ -glycidoxypropyltrimethoxysilane, ⁇ -glycidoxypropyltriethoxysilane, ⁇ -mercaptotrimethoxysilane, ⁇ -aminopropyltrimethoxysilane, ⁇ -aminoethyl- ⁇ -aminopropyltrimethoxysilane, ⁇ -ureidopropyltrimethoxysilane, or the like can be used.
• the compounding quantity of the connecting agent is preferably 0.01 part by mass to 1 part by mass based on 100 parts by mass of the combination of the curing agent and curable insulating resin. In view of improving adhesion, 0.01 part by mass or more is preferable and in view of reliability, 1 part by mass or less is preferable.
• an ion scavenger can be compounded as an additive.
• an organic ion exchanger, an inorganic ion exchanger, an inorganic ion adsorbing agent, or the like can be used, an inorganic ion exchanger, which has excellent heat resistance, is preferable.
• an inorganic ion exchanger a zirconium compound, a zirconium-bismuth compound, an antimony-bismuth compound, a magnesium-aluminum compound, or the like can be used.
• the amphoteric ion type is preferable because it can exchange both metal ions (cations), which directly cause ion migration, and anions, which cause the elevation of electrical conductivity and the formation of metal ions.
• the average particle size of the ion scavenger to be compounded is preferably 0.01 ⁇ m or more and 5 ⁇ m or less, more preferably 0.01 ⁇ m or more and 1 ⁇ m or less.
• an adhesive layer is provided on a biaxially stretchable film to form a laminate, conductive particles having an average particle size of 1 to 8 ⁇ m are closely packed on the laminate to fabricate a conductive-particle adhered film, the conductive-particle adhered film is biaxially stretched and held so that the average particle distance between the conductive particles and adjacent particles is at least once but five times or less the average particle size of the conductive particles and 20 ⁇ m or less, and the conductive particles are transferred on an adhesive sheet containing at least a curing agent and a curable insulating resin and having a thickness of 1.5 times or more the average particle distance of the conductive particles and 40 ⁇ m or less, to manufacture the anisotropic conductive adhesive sheet of the present invention
• the biaxially stretchable film is a long film, and the adhesive sheet is also a long adhesive sheet.
• the peeling strength of the surface of the surface metal of the conductive particles to be used is preferably within a range between 0.5 gf/cm and 40 gf/cm, more preferably within a range between 1 gf/cm and 20 gf/cm.
• the measuring method a method wherein a glass plate coated with a metal having the same composition as the surface metal of the conductive particles is prepared, a film having a width of 2 cm coated with the adhesive is adhered, and 90° peeling strength is measured, can be used.
• the peeling strength is preferably 0.5 gf/cm or more; and in view of transferring particles to the adhesive sheet after stretching, the peeling strength is preferably 40 gf/cm or less.
• the thickness of the adhesive layer is preferably within a range between 1/50 and twice, more preferably 1/10 and once the average particle size of the conductive particles to be used.
• the thickness is preferably 1/50 or more the average particle size of the conductive particles; and in view of transferring particles to the adhesive sheet after stretching, the thickness is preferably twice or less.
• a method wherein the adhesive dispersed or dissolved in a solvent or water is applied using a heretofore known method, such as a gravure coater, die coater, knife coater, bar coater, or the like, and dried, can be used.
• a hot-melt-type adhesive is applied, roll coating without solvent can be performed.
• the above-described method wherein conductive particles are dispersed and arranged on a stretchable film and fixed can be used.
• the film thickness of the film after stretching is preferably 1/10 to once, more preferably 1 ⁇ 5 to 1 ⁇ 2 of the sum of the film thickness of the adhesive sheet to be transferred and the support film of the adhesive sheet.
• the film thickness is preferably 1/10 or more of the sum of the film thickness; and in view of transferring particles to the adhesive sheet after stretching, the film thickness is preferably once or less of the sum of the film thickness.
• the present invention also relates to a method for electrically connecting an electronic circuit component having fine connecting terminals to a circuit board having a circuit corresponding to the electronic circuit component using an anisotropic conductive adhesive sheet.
• the height of the fine connecting terminal of the electronic circuit component is 3 to 15 times the average particle distance of the conductive particles but not greater than 40 ⁇ m
• the distance between the fine connecting terminals is 1 to 10 times the average particle distance but not greater than 40 ⁇ m
• the pitch of the fine connecting terminals is 3 to 30 times the average particle distance of the conductive particles but not greater than 80 ⁇ m.
• the electronic circuit component is electrically coupled to the circuit board having a circuit corresponding to the electronic circuit component using the anisotropic conductive adhesive sheet of the present invention.
• the height of the connecting terminal is 3 to 15 times the average particle distance of the conductive particles but not greater than 40 ⁇ m, and 4 to 10 times are preferable.
• the mechanical strength of the connecting structure not less than 3 times are preferable; and in view of the movement of conductive particles due to the resin flow of the adhesive sheet occurring in connecting, the lowering of connecting properties due to lowered number of conductive particles in the lower portion of the connecting terminal, the movement of conductive particles present in the area other than the connecting portion, and the lowering of insulating properties due to coagulation, not more than 15 times and not more than 40 ⁇ m are preferable.
• the distance between connecting terminals is once to 10 times the average particle distance but not greater than 40 ⁇ m, preferably once to 10 times but not greater than 20 ⁇ m, and more preferably 2 to 5 times but not greater than 15 ⁇ m.
• the pitch is 3 to 30 times the average particle distance but not greater than 80 ⁇ m, and preferably 5 to 20 times but not greater than 40 ⁇ m.
• 3 times or more is preferable; and in view of fine connecting, not more than 30 times but not greater than 80 ⁇ m is preferable.
• the present invention also relates to a fine connecting structure connected by the above-described fine connecting method.
• the material of the circuit bard coupled using an anisotropic conductive adhesive sheet of the present invention can be either an organic board or an inorganic board.
• organic board a polyimide film board, a polyamide film board, a polyethersulfone film board, a rigid board produced by impregnating epoxy resin into glass cloth, a rigid board produced by impregnating bismaleimide-triazine resin into glass cloth, or the like can be used.
• the inorganic board a silicon board, a glass board, an alumina board, an aluminum nitride board, or the like can be used.
• an inorganic wiring material such as indium tin oxide, indium zinc oxide or the like; a metal wiring material, such as gold-plated copper, chromium-copper, aluminum and gold bumps; a composite wiring material wherein an inorganic wiring material such as indium tin oxide is covered with a metallic material, such as aluminum and chromium, or the like can be used.
• the distance between connecting circuits used in the present invention is preferably 3 to 500 times the average particle size of conductive particles in view of electrical insulating properties.
• the connecting area of the circuit portion to be connected is preferably 1 to 10000 times the square of the value of the above-described average particle size. From the aspect of connecting properties, 2 to 100 times are particularly preferable
• the anisotropic conductive adhesive sheet of the present invention or the connecting structure of the present invention can be used for connecting the display device, such as a liquid crystal display device, a plasma display device, and an electroluminescence display device to a wiring board; mounting electronic parts, such as an LSI, of these devices; connecting other devices to a wiring board; and mounting electronic parts, such as an LSI.
• the anisotropic conductive adhesive sheet or the connecting structure can be suitably used in the plasma display device, and the electroluminescence display device, which require reliability.
• a non-stretched polypropylene film having a thickness of 45 ⁇ m coated with a nitrile rubber latex-methyl methacrylate graft copolymer adhesive having a thickness of 5 ⁇ m Onto a non-stretched polypropylene film having a thickness of 45 ⁇ m coated with a nitrile rubber latex-methyl methacrylate graft copolymer adhesive having a thickness of 5 ⁇ m, a single layer of gold-plated plastic particles of an average particle size of 3.0 ⁇ m were applied so as to be substantially free of gaps.
• a container having a width larger than the width of the film packed with the gold-plated plastic particles so as to have a thickness of several layers was prepared, the film with the adhesive applied surface facing downward was pressed against the gold-plated particles to adhere, and thereafter, excessive particles were scraped down with a scraper made of a non-woven fabric.
• the particle size distribution of the gold-plated plastic particles was previously measured using a laser particle size distribution meter (HELOS SYSTEM, manufactured by JEOL), and the value at 50% cumulative value was made to be the average particle size.
• the film was fixed using a biaxial stretching equipment (corner stretching type biaxial stretching equipment of pantograph system, X6H-S manufactured by Toyo Seiki Seisaku-sho, Ltd.) using 10 chucks in each of lengthwise and crosswise directions, preheated at 150° C. for 120 seconds, then, stretched by 100% in each of lengthwise and crosswise directions at a rate of 20%/sec and fixed.
• the adhesive sheet was peeled off to obtain an anisotropic conductive adhesive sheet.
• 100 particles were randomly selected, and the distance from the surface of the anisotropic conductive adhesive sheet was measured using a laser microscope that can measure the displacement in the Local point direction (VK9500, manufactured by Keyence Corporation, shape measurement resolution: 0.01 ⁇ m).
• VK9500 the Local point direction
• 92% were single particles.
• the average distance between particles was 4.17 ⁇ m, which was 1.39 times the average particle size.
• Example 2 Onto a non-stretched polypropylene film having a thickness of 45 ⁇ m coated with a nitrile rubber latex-methyl methacrylate graft copolymer adhesive having a thickness of 5 ⁇ m, a single layer of gold-plated plastic particles of an average particle size of 2.5 ⁇ m were applied in the same manner as in Example 1 so as to be substantially free of gaps.
• the film was stretched using biaxial stretching equipment by 120% in each of lengthwise and crosswise directions in the same manner as in Example 1, and fixed.
• the adhesive sheet was peeled off to obtain an anisotropic conductive adhesive sheet From the conductive particles on the obtained anisotropic conductive adhesive sheet, 100 particles were randomly selected, and the distance from the surface of the anisotropic conductive adhesive sheet was measured using a laser displacement gage. As a result, it was known that 95% of the conductive particles were present within the layer shown in a range of 4.8 ⁇ m in the film thickness direction of the anisotropic conductive adhesive sheet of the 100 measured conductive particles, 91% were single particles. The average distance between particles was 4.24 ⁇ m, which was 1.70 times the average particle size.
• a liquid epoxy resin containing a microcapsule-type latent imidazole curing agent (average particle size of the microcapsules: 5 ⁇ m, activating temperature: 125° C.) was compounded and dispersed. Thereafter, the dispersion was applied onto a polyethylene terephthalate film having a thickness of 50 ⁇ m, wind-dried at 60° C. for 15 minutes to obtain a film-like adhesive sheet A having a film thickness of 15 ⁇ m.
• a film-like adhesive sheet B having a film thickness of 5 ⁇ m was obtained in the same manner as described except that a polyethylene terephthalate film undergone easy-peeling treatment was used.
• Example 2 Onto a non-stretched polypropylene film having a thickness of 45 ⁇ m coated with a nitrile rubber latex-methyl methacrylate graft copolymer adhesive having a thickness of 5 ⁇ m, a single layer of gold-plated nickel particles of an average particle size of 2.6 ⁇ m were applied in the same manner as in Example 1 so as to be substantially free of gaps.
• the film was stretched using biaxial stretching equipment by 200% in each of lengthwise and crosswise directions in the same manner as in Example 1, and fixed.
• the adhesive sheet After stacking the adhesive sheet A on the stretched film, the adhesive sheet was peeled off, and the adhesive sheet B was stacked on the peeled surface to obtain an anisotropic conductive adhesive sheet
• 100 particles were randomly selected, and the distance from the surface of the anisotropic conductive adhesive sheet was measured using a laser displacement gage.
• 95% of the conductive particles were present within the layer shown in a range of 4.9 ⁇ m in the film thickness direction of the anisotropic conductive adhesive sheet.
• 91% were single particles.
• the average distance between particles was 7.22 ⁇ m, which was 2.77 times the average particle size.
• anisotropic conductive adhesive sheet 100 particles were randomly selected, and the distance from the surface of the anisotropic conductive adhesive sheet was measured using a laser displacement gage. As a result, it was known that conductive particles were randomly present in the film thickness direction of the anisotropic conductive adhesive sheet. Of the 100 measured conductive particles, 70% were single particles.
• anisotropic conductive adhesive sheet was obtained in the same manner as in Example 1 except that gold-plated plastic particles of an average particle size of 10 ⁇ m were used, and the sheet was stretched by 60%. From the conductive particles on the obtained anisotropic conductive adhesive sheet, 100 particles were randomly selected, and the distance from the surface of the anisotropic conductive adhesive sheet was measured using a laser displacement gage. As a result, it was known that 96% of the conductive particles were present within the layer shown in a range of 19.2 ⁇ m in the film thickness direction of the anisotropic conductive adhesive sheet.
• a connecting pad (width: 66 ⁇ m, length: 120 ⁇ m) of indium-tin oxide (thickness: 1400 angstrom) was formed so as to be connected in the position relationship to be a pair with a gold bump on the thin aluminum film adjacent to a gold bump on the above-described thin aluminum film.
• a connecting pad width: 66 ⁇ m, length: 120 ⁇ m
• indium-tin oxide thickness: 1400 angstrom
• an anisotropic conductive adhesive sheet having a width of 2 mm and a length of 17 mm was temporarily bonded so that the entire connecting pad was covered, and after pressing at 80° C. under 0.3 MPa for 3 seconds using a pressure bonding head of a width of 2.5 mm, the base film of polyethylene terephthalate was Peeled off.
• a test chip was placed thereon so that the locations of the above-described connecting pad and gold bump are aligned and pressure-bonded at 220° C. for 5 seconds under 5.2 MPa. After pressure bonding, the resistance value between the above-described outgoing wirings (daisy chain of 20 gold bumps) was measured using a resistance meter of a 4-terminal method to be a connecting resistance value.
• a connecting pad (width: 65 ⁇ m, length: 120 ⁇ m) of indium-tin oxide (1400 angstrom) was formed in the position relationship so that 2 gold bumps on the above-described thin aluminum film could be coupled to each other.
• a connecting wiring of a thin indium-tin oxide was formed so that 5 connecting pads could be alternately coupled, and another connecting wiring of a thin indium-tin oxide was formed so that 5 connecting pads could be alternately coupled so as to be pair with them and form a comb-shaped pattern.
• an outgoing wiring of a thin indium-tin oxide film was formed, and a thin aluminum-titanium film (titanium: 1%, 3000 angstroms) was formed on the outgoing wiring to be an insulating property evaluating board.
• an anisotropic conductive adhesive sheet having a width of 2 mm and a length of 17 mm was temporarily bonded so that the entire connecting pad was covered, and after pressing at 80° C. under 0.3 MPa for 3 seconds using a pressure bonding head of a width of 2.5 mm, the base film of polyethylene terephthalate was peeled off.
• a test chip was placed thereon so that the locations of the above-described connecting pad and gold bump are aligned and pressure-bonded at 220° C. for 5 seconds under 2.6 MPa to be an insulating resistance testing board
• a DC voltage of 100 V was impressed between paired outgoing wirings using a constant-voltage constant-current power source.
• the insulation resistance between these wirings was measured once every 5 minutes, and time until the insulation resistance value becomes 10 M ⁇ or less was measured to be an insulation lowering time.
• the case when the insulation lowering time was less than 240 hours was evaluated as ⁇ (bad), and the case of 240 hours or more was evaluated as ⁇ (good);.
• the anisotropic conductive adhesive according to the present invention exerts very excellent insulation reliability.
• the anisotropic conductive adhesive sheet according to the present invention exerts low connecting resistance and high insulation reliability, and is suitable as a bare chip connecting material wherein fine circuit connecting is required, and a connecting material for a high-definition display device and the like.

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• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Adhesive Tapes (AREA)
• Non-Insulated Conductors (AREA)
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• Electric Connection Of Electric Components To Printed Circuits (AREA)
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• Structures For Mounting Electric Components On Printed Circuit Boards (AREA)
• Conductive Materials (AREA)

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• 2004
  • 2004-12-02 WO PCT/JP2004/017944 patent/WO2005054388A1/ja active IP Right Grant
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