JP2011233633A - Circuit connection material, and connection body for circuit member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a circuit connection material achieving sufficiently low connection resistance even when used for connecting a circuit member having a narrowed electrode, and a connection body for a circuit member using the circuit connection material.SOLUTION: The circuit connection material contains: (A) a silica filler subjected to hydrophobic treatment and having an average particle diameter of 3-100 nm; (B) an adhesive component; and (C) conductive particles. An amount of the silica filler is 10-60 mass% or 5-30 vol.% relative to the total amount of the adhesive component.

Description

  The present invention relates to a circuit connection material and a connection member for circuit members.

  The method of mounting the liquid crystal driving IC on the glass panel for liquid crystal display can be roughly divided into two types, COG (Chip-on-Glass) mounting and COF (Chip-on-Flex) mounting. In COG mounting, an anisotropic conductive adhesive containing conductive particles is used as a circuit connection material, and a liquid crystal IC is directly bonded onto a glass panel. On the other hand, in COF mounting, a liquid crystal driving IC is bonded to a flexible tape having metal wiring, and thereafter, they are bonded to a glass panel using an anisotropic conductive adhesive containing conductive particles. Here, the anisotropic conductivity means that the insulation is maintained in the non-pressurization direction while having conductivity in the pressurization direction.

  In conventional COG mounting, a two-layer type circuit connection material consisting of an adhesive layer containing conductive particles and an insulating adhesive layer is used, and an adhesive layer containing conductive particles is pasted on the glass panel side ( Patent Document 1). In this method, since the insulating adhesive layer easily flows during mounting, the flow of the conductive particles can be suppressed, and the capture rate of the conductive particles on the electrode can be improved. In addition, since the insulating adhesive layer is disposed on the chip side, it is possible to reduce the intrusion of conductive particles between the bumps and to improve the occurrence of a short circuit.

  On the other hand, thixotropic properties can be imparted to the adhesive by adding a filler, and studies have been made to increase the resin viscosity and prevent sedimentation of conductive particles having a high specific gravity (Patent Document 2).

  In addition, a method has been developed in which a single conductive particle layer is produced by charging an adhesive layer and spraying conductive particles charged with the opposite charge on the adhesive layer (Patent Document 3). By charging the conductive particles, the particles repel each other and the dispersibility is improved. As a result, the number of conductive particles used is small, leading to cost reduction.

JP 2009-194359 A JP 2003-64330 A Japanese Patent Laid-Open No. 10-302926

  In recent years, as the size and thickness of liquid crystal panels have been reduced, the connection circuit area is required to be reduced.

  On the other hand, when a conventional circuit connection material is used to connect a circuit member having a narrowed electrode, the conductive particles flow out between the circuit electrodes and are trapped between the bump and the glass panel. As a result, the number of conductive particles decreases, and as a result, the connection resistance between the circuit electrodes facing each other increases, resulting in a problem of connection failure.

  Accordingly, the present invention provides a circuit connection material that can achieve a sufficiently low connection resistance even when used to connect a circuit member having a narrowed electrode, and a circuit member connection body using the circuit connection material. The purpose is to do.

  First, the present inventors studied to reduce the fluidity of the resin by highly filling the filler into the circuit connecting material and to improve the capture rate of the conductive particles on the electrode. In addition, it is considered that if the filler is highly filled and the filler exists between the conductive particles and a sufficient distance between the conductive particles can be secured, the insulating characteristics can be improved.

  In general, fillers are roughly classified into organic fillers and inorganic fillers typified by silica fillers. In the case of an organic filler, since it is difficult to produce ultrafine particles such as a silica filler, the average particle diameter generally exceeds 100 nm. For this reason, there is a high possibility of causing conductivity inhibition and the possibility of occurrence of coating streaks during film formation. Moreover, since the organic fillers of very small particles are expensive, using them in large quantities leads to an increase in cost.

  Therefore, the present inventors have studied a silica filler capable of producing ultrafine particles at a low cost. As a result of intensive studies, it was discovered that the silica filler is made hydrophobic by improving the dispersibility of the silica filler in the circuit connecting material, and high filling is facilitated, thereby completing the present invention. It came to.

  That is, the present invention comprises (A) a silica filler having an average particle diameter of 3 to 100 nm that has been subjected to a hydrophobization treatment, (B) an adhesive component, and (C) conductive particles. The circuit connection material is provided in an amount of 10 to 60% by mass based on the total amount of the adhesive component.

  The present invention also includes (A) a silica filler having an average particle size of 3 to 100 nm that has been subjected to a hydrophobic treatment, (B) an adhesive component, and (C) conductive particles, and the silica filler The circuit connection material is provided in an amount of 5 to 30% by volume based on the total amount of the adhesive component.

  Even when the circuit connection material having the above-described configuration is used to connect a circuit member having a narrowed electrode, a sufficiently low connection resistance is achieved, and a circuit member connection body using the circuit connection material is provided. It becomes possible.

  The amount of the silica filler is preferably 10 to 40% by mass.

  On the other hand, the amount of the silica filler is preferably 5 to 20% by volume.

  The average particle size of the silica filler is preferably 5 to 50 nm, and more preferably 5 to 15 nm.

  The silica filler is preferably hydrophobized by attaching or bonding silicone oil.

  The carbon content of the silica filler is preferably 3 to 10% by mass.

  The ratio between the average particle diameter of the conductive particles and the average particle diameter of the silica filler is preferably (average particle diameter of the conductive particles) / (average particle diameter of the silica filler) = 20 to 400.

  The present invention provides the circuit connection material, wherein the conductive particles have a monodispersion rate of 80% or more.

The present invention provides the above circuit connecting material used for connecting a circuit member having an electrode with an area of 3000 μm ² or less and another circuit member.

  The present invention provides the above circuit connection material used for connecting a circuit member having a plurality of electrodes arranged with an interval of 12 μm or less to another circuit member.

  The present invention comprises, in this order, a first circuit member having a first electrode, a cured product obtained by curing the circuit connection material, and a second circuit member having a second electrode. Provided is a circuit member connection body in which a circuit member and the second circuit member are arranged and connected so that the first electrode and the second electrode face each other.

  According to the present invention, there is provided a circuit connection material capable of achieving a sufficiently low connection resistance even when used to connect a circuit member having a narrowed electrode, and a circuit member connection body using the circuit connection material. It becomes possible to provide.

It is sectional drawing which shows one Embodiment of a film-form circuit connection material. It is sectional drawing which shows one Embodiment of the connection body of a circuit member.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the following embodiments.

  The circuit connection material of the present invention contains (A) a silica filler having an average particle diameter of 3 to 100 nm that has been subjected to a hydrophobization treatment, (B) an adhesive component, and (C) conductive particles. The amount of the silica filler is 10 to 60% by mass or 5 to 30% by volume based on the total amount of the adhesive component. Hereinafter, each component will be described in detail.

(A: Silica filler)
Examples of the silica filler according to this embodiment include dry silica, silica aerogel, and wet silica. From the viewpoint that the hydrophobic treatment of the silica surface is easy, dry silica is particularly preferable.

  The average particle size of the silica filler is 3 to 100 nm, preferably 5 to 50 nm, more preferably 5 to 30 nm, particularly preferably 5 to 20 nm, and 5 to 15 nm. Is very preferable, and it is very preferable that it is 7-15 nm. By setting it in the above range, aggregation of the silica filler can be suppressed, and coating flaws, physical property variations and thickness variations caused by the aggregated silica filler can be improved even when the film is formed, and the film moldability is maintained. It becomes possible. On the other hand, when the average particle diameter of the silica filler is less than 3 nm, the silica filler is strongly aggregated and tends to be difficult to disperse, and when it exceeds 100 nm, the thickening effect or the thixotropic improvement effect tends to be insufficient. . The average particle diameter of the silica filler can be measured by a dynamic light scattering method.

The silica filler is subjected to a hydrophobic treatment. The “hydrophobizing treatment” in the present embodiment means that a silicone oil or a silane coupling agent is attached or bonded to a silica filler. When the silicone oil or silane coupling agent has a reactive organic group to be described later, the reactive organic group can be supported on the silica filler by a hydrophobic treatment. As a result, high filling of the silica filler into the circuit connecting material is facilitated. Furthermore, the hydrophobization treatment reduces the water absorption rate of the silica filler and suppresses the occurrence of short circuits. The reactive organic group is preferably one that reacts with the adhesive component in the present invention and does not particularly adversely affect the curing reaction or the like. Examples of such a reactive organic group include an amino group, a glycidyl group, a mercapto group, a ureido group, a hydroxy group, a methacryloxy group, and a carboxyl group. Among these reactive organic groups, an amino group (—NH ₂ ), a mercapto group (—SH), a carboxyl group (—COOH), a ureido group (—NHCONH ₂ ), and a hydroxy group (—OH) having active hydrogen. Is preferable because it is considered that an addition or a hydrogen bond is formed on a hydrophilic group in the adhesive component, for example, an epoxy group (oxirane ring) present at an end of the epoxy resin. A glycidyl group is preferred because it is considered to undergo a ring-opening addition reaction in the presence of an epoxy group and an amine catalyst.

  In order to support these reactive organic groups on the silica filler, for example, the silica filler is hydrophobized using a compound having in its molecule both the reactive organic group and a functional group capable of binding to the silica filler. Preferably it is done. Examples of such compounds include silane coupling agents and silicone oils as shown below.

(A) Silane coupling agent As a silane coupling agent suitable for the hydrophobic treatment of the silica filler according to the present embodiment, there is a compound represented by the following general formula (I).

X _m SiY _n (I)

  In said formula, X shows the functional group or alkyl group which brings about a coupling | bonding with a silica filler, m shows the integer of 1-3. At least one of X is preferably a functional group that provides a bond with the silica filler. As a functional group which brings about the coupling | bonding with the said silica filler, an alkoxy group, an acyloxy group, an oxime group (-C (R) = NOH), and a halogen atom are mentioned, for example. In the process of hydrophobizing the silica filler, these groups are hydrolyzed and substituted with hydroxy groups, and it is considered that the silane coupling agent is bonded to the silica filler through covalent bonds, hydrogen bonds, and the like. The alkoxy group is preferably a methoxy group or an ethoxy group, the acyloxy group is preferably an acetooxy group, and the halogen atom is preferably a chlorine atom.

  Y in the above formula represents a group having a reactive organic group, for example, at least one reactive organic group selected from the group consisting of an amino group, a glycidyl group, a mercapto group, a ureido group, a methacryloxy group, and a hydroxy group. And a hydrocarbon group substituted with. n represents an integer of 1 to 3, and is selected so that m + n is 4. 1-20 are preferable and, as for carbon number of the said hydrocarbon group, 3-8 are more preferable. Some of the carbon atoms in the hydrocarbon group may be substituted with oxygen atoms.

  Examples of such silane coupling agents include, but are not limited to, γ-aminopropyltriethoxysilane, vinyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ -Methacryloxypropyltrimethoxysilane, gamma-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) 3-aminopropyltrimethoxysilane, Vinyltriacetoxysilane, (3-glycidoxypropyl) methyldiethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-hydroxypropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, (3-mercaptopro Pyr) methyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, methyltris (methylethylketoxime) silane and vinyltris (methylethylketoxime) silane. These can be used individually by 1 type or in combination of 2 or more types.

(B) Silicone oil The silicone oil suitably used for the hydrophobic treatment of the silica filler according to this embodiment is a silicone oil typified by dimethylpolysiloxane and methylhydrogenpolysiloxane. A modified silicone oil in which the group is substituted with at least one reactive organic group selected from the group consisting of an amino group, a hydroxy group, a carboxyl group, a glycidyl group and a mercapto group. These modified silicone oils have, for example, a structure represented by the following general formula (II).

In the above formula, A represents a reactive organic group selected from an amino group, a hydroxy group, a carboxyl group, a glycidyl group, and a mercapto group, R ¹ represents hydrogen or an alkyl group (preferably a methyl group), and R ² Represents a lower alkylene group such as a methylene group, and x and y represent an integer of 1 or more, preferably 1 to 3. In addition, although the siloxane unit which has the reactive organic group A may be continuing in block shape, generally a reactive organic group substitutes the siloxane unit in a molecule regularly or randomly. The reactive organic group enables the reaction between the silicone oil and the adhesive component. Such a modified silicone oil may be a commercially available product, and examples thereof include KF96 (trade name) manufactured by Shin-Etsu Chemical Co., Ltd.

  The amount of the reactive organic group is preferably 0.01 to 2.0% by mass based on silicone oil. If this amount is less than 0.01% by mass, the reaction with the adhesive component is insufficient and the improvement effect such as thixotropy tends to not reach a satisfactory level. The characteristics are impaired, and the bondability with the silica filler tends to decrease. The modified silicone oil preferably has a polymerization degree of 10 to 500. When the degree of polymerization is less than 10, the volatility is high and the silica filler tends to be volatilized by heating. When the degree of polymerization exceeds 500, the viscosity increases and the silica filler can be uniformly hydrophobized. It tends to disappear. These can be used individually by 1 type or in combination of 2 or more types.

(C) Hydrophobic improver In order to further improve the hydrophobicity of the silica filler and improve the viscosity and thixotropy of the adhesive component, the silica filler was hydrophobized with the silane coupling agent and / or silicone oil. Later or simultaneously, it may be treated with a hydrophobicity improver. The hydrophobicity improver is preferably an organosilicon compound that reacts or physically adsorbs with the silica filler, such as hexamethyldisilazane, dimethylpolysiloxane, alkyltrialkoxysilane, and dialkyldialkoxysilane. It is done. These can be used individually by 1 type or in combination of 2 or more types.

  The method of hydrophobizing the silica filler using the silane coupling agent, the silicone oil or the like is not particularly limited, and a generally known method can be used. For example, a silica filler is charged into a container equipped with a stirrer typified by a Henschel mixer, and the silane coupling agent or silicone oil is added while stirring and mixed uniformly. It is preferable to add by spraying so that mixing is performed more uniformly. At the same time, or before or after these hydrophobizing treatments, the hydrophobicity improver may be added.

  The amount of the silane coupling agent and the silicone oil is preferably 1 to 50 parts by mass and more preferably 5 to 30 parts by mass with respect to 100 parts by mass of the silica filler. When this amount is less than 1 part by mass, an untreated part tends to occur, and when it exceeds 50 parts by mass, excess silicone oil tends to dissolve in the varnish.

  After the silane coupling agent and / or silicone oil is added and mixed, the mixture is preferably heated for about 10 minutes to 1 hour. The heating temperature is preferably 100 to 350 ° C. If this temperature is less than 100 ° C., the reaction between the silane coupling agent and the silica filler and the adsorption and orientation of the silicone oil on the silica filler become insufficient, and it tends to be difficult to exert a satisfactory effect. If it exceeds 1, the decomposition of the functional group of the organosilicon tends to start.

Thus, it is preferable that the carbon content rate of the silica filler to which the hydrophobization process was performed is 3-10 mass%. When the carbon content is within this range, the silica filler is sufficiently hydrophobized and the effects of the present invention are easily achieved. This carbon content is measured by changing the carbon contained in the silica filler to CO ₂ by a coulometric method. The production of CO ₂ by combustion can be performed, for example, in a tube furnace electrically heated to 1000 ° C. By using a catalyst mixture, almost complete combustion can occur. Coulometric measurement is performed with a highly automated instrument, and an instrument manufactured by LECO (trade name: OENORM G 1072) can be preferably used. The carbon contained in the sample reacts with oxygen in an induction furnace to become CO, and further changes to CO ₂ by reoxidation at 450 ° C. in the presence of a catalyst. The concentration or mass of the generated CO ₂ is measured with an infrared cell. can do. Based on the measured amount of CO ₂ , the carbon content of the silica filler can be determined by the following formula. [Carbon Content of Silica Filler (% by Mass)] = (Detected Carbon Amount / Sample Amount) × 100

  Here, it is exemplified that the hydrophobization treatment is performed in advance before mixing the silica filler and the adhesive component. However, the silane coupling agent and the silicone oil are contained in the adhesive component, and the silica filler is dispersed therein. It may be hydrophobized.

  The amount of the silica filler is preferably 10 to 60% by mass, more preferably 10 to 50% by mass, even more preferably 10 to 40% by mass, based on the total amount of the adhesive component. It is very preferably 20 to 40% by mass. By setting this range, the connection resistance value of the circuit connecting material can be kept low, and the ratio of the number of conductive particles remaining on the electrode to the total number of conductive particles in the circuit connecting material (hereinafter referred to as particle trapping rate) is improves.

  Moreover, it is preferable that the quantity of a silica filler is 5-30 volume% with respect to the total amount of an adhesive component, It is more preferable that it is 5-25 volume%, It is still more preferable that it is 5-20 volume%. Preferably, it is very preferable that it is 10-20 volume%. By setting it as this range, the connection resistance value of the circuit connection material can be kept low, and the particle trapping rate can be improved.

  Furthermore, although the specific mechanism is not clear, it is possible to improve the decrease in the tack force of the circuit connecting material, which usually decreases as the silica filler is highly charged.

(B: Adhesive component)
As an adhesive component used for the circuit connection material according to the present embodiment, for example, a mixture of a heat-reactive resin and a curing agent can be suitably used. Among these, it is more preferable to use a mixture of an epoxy resin and a latent curing agent. In addition, a mixture of a radical reactive resin and an organic peroxide or an energy ray curable resin that is cured by irradiation with energy rays such as ultraviolet rays can also be used as an adhesive component.

Examples of the epoxy resin include bisphenol type epoxy resins derived from epichlorohydrin and bisphenol A, bisphenol F, bisphenol AD, and the like, epoxy novolac resins derived from epichlorohydrin and phenol novolac or cresol novolac, and naphthalene. Examples thereof include naphthalene-based epoxy resins having a skeleton containing a ring, or epoxy resins obtained from various epoxy compounds having two or more glycidyl groups in one molecule such as glycidylamine, glycidyl ether, biphenyl, and alicyclic. It is done. These can be used individually by 1 type or in combination of 2 or more types. From the viewpoint of preventing electromigration, these epoxy resins are preferably high-purity products in which impurity ions (Na ⁺ , Cl ^−, etc.), hydrolyzable chlorine, etc. are reduced to 300 ppm or less.

  Examples of the latent curing agent include imidazole-based curing agents, hydrazide-based curing agents, boron trifluoride-amine complexes, sulfonium salts, amine imides, polyamine salts, and dicyandiamide. As a commercial item, Asahi Kasei E-Materials Co., Ltd. NovaCure HX-3941 is mentioned, for example.

  In addition to the above components, rubber components such as butadiene rubber, acrylic rubber, styrene-butadiene rubber and silicone rubber are mixed with the adhesive component in order to reduce the stress after bonding or to improve the adhesion. You can also In addition, the filler, softener, accelerator, anti-aging agent, colorant, flame retardant, thixotropic agent, coupling agent, phenol resin, melamine resin, and isocyanate are within the range that does not hinder the achievement of the object of the present invention. Etc. can also be contained.

  Furthermore, it is preferable to mix | blend thermoplastic resins (film-forming polymer), such as a phenoxy resin, a polyester resin, and a polyamide resin, with an adhesive agent component from a film-forming viewpoint. Mixing these film-forming polymers is also preferable from the viewpoint of relieving stress during curing of the thermally reactive resin. From the viewpoint of improving adhesiveness, it is more preferable that the film-forming polymer has a functional group such as a hydroxy group. The circuit connection material may be used in a paste form.

(C: conductive particles)
As the conductive particles according to the present embodiment, gold, silver, copper, platinum, zinc, iron, palladium, nickel, tin, chromium, titanium, aluminum, cobalt, germanium, cadmium, and other metals, ITO, solder, and other metal particles And particles such as carbon. The conductive particles may be particles in which core particles are covered with one or more layers, and the outermost layer is a conductive layer. In this case, the outermost layer is preferably nickel, gold, palladium or the like. The conductive particles may be those in which the surface of a transition metal such as nickel is coated with gold or palladium.

  Furthermore, the thing which coat | covered electrically conductive substances, such as the metal mentioned above, to electrically-conductive particle | grains, such as nonelectroconductive glass, ceramics, and plastics, can also be used. When the conductive particles are made of insulating particles coated with a conductive material and the outermost layer is gold or palladium and the core insulating particles are plastic, or the conductive particles are hot-melt metal particles, heating is applied. It is preferable because it has deformability due to pressure, increases the contact area with the electrode at the time of connection, and improves reliability. Such conductive particles can be produced, for example, by coating the core with insulating particles by plating or the like. Examples of the coating method include electroless plating, displacement plating, electroplating, and sputtering. It is preferable that the conductive particles have a spherical shape because the effects of the present invention can be easily obtained.

If the average particle size of the conductive particles is smaller than the height of the electrode of the circuit to be connected, shorting between adjacent electrodes tends to decrease. Therefore, the average particle size is preferably 1 to 10 μm, and more preferably 1 to 8 μm. It is preferably 2 to 6 μm, more preferably 3 to 5 μm, and most preferably 3 to 4 μm. Further, those having a 10% compression modulus (K value) of 100 to 1000 kgf / mm ² can be appropriately selected and used.

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

  The ratio of the average particle size of the conductive particles to the average particle size of the silica filler is preferably (average particle size of the conductive particles) / (average particle size of the silica filler) = 20 to 400, preferably 300 to 400 is more preferable. By setting it as such conditions, the influence on the connection resistance by aggregation of a silica filler can be made small.

  Furthermore, if necessary, these conductive particles can be subjected to an insulating coating treatment. Examples of the insulating coating treatment include a method of attaching or bonding insulating small particles to the conductive particles, a method of forming a film of an insulating resin on the surface of the conductive particles, and the like.

  Examples of the insulating small particles include inorganic oxide fine particles and organic fine particles, but inorganic oxide fine particles are preferable from the viewpoint of sufficiently increasing the conductivity between opposing circuit electrodes. As the inorganic oxide fine particles, for example, fine particles made of an oxide containing at least one element selected from silicon, aluminum, zirconium, titanium, niobium, zinc, tin, cerium and magnesium can be suitably used. Among these, from the viewpoint of improving the insulating properties, silica is preferable, and water-dispersed colloidal silica having a controlled average particle diameter is more preferable.

  The average particle size of the insulating small particles is preferably 20 to 500 nm. If this average particle size is less than 20 nm, the insulating small particles covering the insulating coated conductive particles do not function as an insulating layer, and there is a tendency that short circuit between adjacent circuit electrodes on the same substrate cannot be sufficiently suppressed. is there. On the other hand, if it exceeds 500 nm, the conductivity between the circuit electrodes facing each other tends to decrease.

  Such electroconductive particle can be used individually by 1 type or in combination of 2 or more types.

  The amount of the conductive particles is preferably 0.1 to 30% by volume with respect to the total amount of the adhesive component from the viewpoint of improving the insulation between the adjacent electrodes and the conductivity between the opposing electrodes. 1 to 25% by volume is more preferable.

  The monodispersion rate of the conductive particles is preferably 80% or more, and more preferably 90% or more. Here, the monodispersion rate of the conductive particles means the ratio of the conductive particles present alone in the whole conductive particles in the circuit connecting material, and is represented by the following formula. [Monodispersion rate of conductive particles (%)] = (number of single particles / total number of measured particles) × 100. When the monodispersion rate is in such a range, an effect of improving the insulating characteristics is obtained.

(Film formation and usage)
For film formation, for example, an adhesive component containing an epoxy resin, acrylic rubber, and a latent curing agent is dissolved or dispersed in an organic solvent to be liquefied, and conductive particles and silica filler are added thereto to disperse the adhesive component. It is carried out by removing the solvent at a temperature below the activation temperature of the curing agent. As the organic solvent, for example, a mixed solvent of an aromatic hydrocarbon type and an oxygen-containing type is preferable from the viewpoint of improving the solubility of the adhesive component. Examples of the aromatic hydrocarbon organic solvent include toluene, and examples of the oxygen-containing organic solvent include ethyl acetate and methyl ethyl ketone.

  FIG. 1 is a cross-sectional view showing an embodiment of a film-like circuit connecting material. The film-like circuit connection material 1 is obtained by forming a circuit connection material in which a plurality of conductive particles 5 are dispersed in a resin composition layer 3 containing a silica filler and an adhesive component into a film shape. The film-like circuit connection material 1 can be produced, for example, by coating the circuit connection material with a predetermined thickness on a support film. As the support film, a PET film or the like surface-treated so as to have releasability is preferably used.

  When the film-like circuit connecting material 1 is heated and pressed in a state sandwiched between a pair of opposing circuit members, the circuit electrodes melted and flowed to electrically connect each other, Hardens and develops adhesive strength.

  Although the film-like circuit connecting material 1 in FIG. 1 has only one layer, the circuit connecting material of the present invention includes an ACF layer containing an adhesive component and conductive particles, an adhesive component, and conductive particles instead. It can also be divided into at least two layers with an NCF layer that does not contain. At this time, the silica filler in the present invention can be contained in both the ACF layer and the NCF layer. However, when the silica filler is contained in the ACF layer, it is 10 to 60 mass based on the total amount of the adhesive component of the ACF layer. % Or 5 to 30% by volume is preferable.

  The thickness of the film-like circuit connection material thus formed is relatively determined in consideration of the average particle size of the conductive particles and the characteristics of the circuit connection material, and is preferably 1 to 100 μm. More preferably, it is 1-30 micrometers. When the thickness of the anisotropic conductive adhesive film is less than 1 μm, sufficient adhesion tends to be not obtained, and when it exceeds 100 μm, a large amount of conductive particles tend to be required to obtain conductivity between opposing circuit electrodes. There is.

  The film-like circuit connection material 1 is used, for example, for connecting chip components such as a semiconductor chip, a resistor chip, and a capacitor chip, or circuit members such as a printed board.

  FIG. 2 is a cross-sectional view showing an embodiment of a circuit member connection body. A circuit member connection body 101 shown in FIG. 2 includes a first circuit board 10 and a first circuit member 10 having a first circuit electrode 13 having a first circuit electrode 13 formed on a main surface thereof. The second circuit board 21 and the second circuit member 20 having the second circuit electrode 23 formed on the main surface thereof are made of a cured product obtained by curing the above-described circuit connection material. The circuit connection member 1a formed between the two circuit members 10 and 20 is connected. In the circuit member connection body 101, the first circuit electrode 13 and the second circuit electrode 23 face each other and are electrically connected.

  The circuit connection member 1a is composed of a cured product 3a of a resin composition layer containing a silica filler and an adhesive component, and conductive particles 5 dispersed therein. The first circuit electrode 13 and the second circuit electrode 23 are electrically connected via the conductive particles 5.

  The first circuit board 11 is a resin film containing at least one resin selected from the group consisting of polyester terephthalate, polyethersulfone, epoxy resin, acrylic resin, and polyimide resin.

  The circuit electrode 13 is formed of a material having conductivity that can function as an electrode (preferably at least one selected from the group consisting of gold, silver, tin, platinum group metals, and indium-tin oxide). . A plurality of circuit electrodes 13 are formed on the main surface of the first circuit board 11.

  The second circuit board 21 is a glass substrate, and a plurality of second circuit electrodes 23 are formed on the main surface of the second circuit board 21.

  The circuit member connection body 101 includes, for example, the first circuit member 10, the film-like circuit connection material 1, and the second circuit member 20, and the first circuit electrode 13 and the second circuit electrode 23. The first circuit member 10 and the first circuit electrode 10 are electrically connected to each other by heating and pressurizing the laminated body laminated in this order so as to face each other. It is obtained by a method of connecting the second circuit member 20.

  In this method, first, the circuit connection material 1 is temporarily bonded by heating and pressurizing in a state where the film-like circuit connection material 1 formed on the support film is bonded to the second circuit member 20. Then, after peeling the said support film, the 1st circuit member 10 can be mounted, aligning the position of a circuit electrode, and a laminated body can be prepared.

  Conditions for heating and pressurizing the laminate are appropriately adjusted so that the circuit connecting material is cured and sufficient adhesive strength is obtained in accordance with the curability of the adhesive composition in the circuit connecting material.

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

Further, since the circuit connecting material is improved scavenging onto the electrodes of the conductive particles of the present invention, and the circuit member having an electrode area of 3000 .mu.m ² below, a plurality of electrodes spaced intervals less than 12μm It can use suitably as a material which connects the circuit member etc. which have.

  Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited thereto.

(Silica filler 1)
200 g of dry silica filler (Nippon Aerosil Co., Ltd., trade name: Aerosil 200) having an average particle diameter of 12 nm is placed in a 15 liter reaction tank, and dimethyl silicone oil (Shin-Etsu Chemical Co., Ltd., trade name: KF96, polymerization degree: 10) is added. 26 g was added. Further, the inside of the system was replaced with nitrogen gas while stirring, and the temperature was raised to 280 ° C. while flowing the nitrogen gas, kept for 20 minutes, and then cooled to room temperature. Then, the silica filler (silica filler 1) hydrophobized with the modified silicone oil was dispersed in ethyl acetate to prepare a dispersion having a concentration of 13% by mass. The carbon content of the hydrophobized silica filler was 5% by mass.

(Silica filler 2)
Silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., γ-methacryloxypropyltrimethoxysilane, trade name: KBM-503) instead of dimethyl silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KF96, degree of polymerization: 10) The silica filler 2 was produced in the same manner as in the case of the silica filler 1 except that. Thereafter, the silica filler 2 was dispersed in ethyl acetate to prepare a dispersion having a concentration of 13% by mass. The carbon content of the hydrophobized silica filler was 6% by mass.

(Silica filler 3)
200 g of dry silica filler having an average particle size of 200 nm was placed in a 15 liter reaction vessel, and 26 g of dimethyl silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KF96, degree of polymerization: 10) was added. Further, the inside of the system was replaced with nitrogen gas while stirring, and the temperature was raised to 280 ° C. while flowing the nitrogen gas, kept for 20 minutes, and then cooled to room temperature. Then, the silica filler (silica filler 3) hydrophobized with the modified silicone oil was dispersed in ethyl acetate to prepare a dispersion having a concentration of 13% by mass. The carbon content of the hydrophobized silica filler was 7% by mass.

(Silica filler 4)
A dry silica filler (Nippon Aerosil Co., Ltd., trade name: Aerosil 200) not subjected to hydrophobization treatment was dispersed in ethyl acetate to prepare a dispersion having a concentration of 13% by mass. The carbon content of the silica filler not subjected to the hydrophobization treatment was 0-1% by mass.

Example 1
Copolymer of phenoxy resin (Union Carbide, trade name: PKHC) and acrylic rubber (40 parts by mass of butyl acrylate, 30 parts by mass of ethyl acrylate, 30 parts by mass of acrylonitrile, and 3 parts by mass of glycidyl methacrylate, weight average molecular weight : 850,000) was dissolved in 20 g of ethyl acetate to obtain a solution having a polymer concentration of 41% by mass. To this solution, 50 g of a liquid epoxy (epoxy equivalent 185, manufactured by Asahi Kasei E-Materials Co., Ltd., trade name: Novacure HX-3941) containing a microcapsule type latent curing agent was added and stirred to prepare an adhesive solution. . To this adhesive solution, a dispersion containing 40% by mass of silica filler 1 (35 g) based on the total amount of adhesive components was added and stirred. To 100 g of this solution, 20 g of insulating coated conductive particles having an average particle size of 3.0 μm (particles in which plastic particles are nickel-plated and gold-plated and coated with colloidal silica) are mixed to form a varnish (adhesive) The content of the insulating coating conductive particles was 9% by volume) with respect to the total amount of the components.

  This varnish was coated on a separator (thickness: 40 μm), which was a polyethylene-treated polyethylene terephthalate film, using a roll coater and dried at 80 ° C. for 5 minutes to prepare a film-like circuit connecting material having a thickness of 25 μm.

  Using the produced film-like circuit connection material, a chip (1.7 mm × 17 mm, thickness: 0.5 mm) with gold bumps (area: 30 μm × 90 μm, space (pitch) 10 μm, height: 15 μm, number of bumps: 362) ) And a glass substrate with an ITO circuit (Geomatec, thickness: 0.7 mm) were connected as follows.

A film-like circuit cut into a predetermined size (2 mm × 19 mm) with the surface opposite to the surface on which the separator of the film-like circuit connection material is provided facing the surface on which the ITO circuit of the glass substrate with the ITO circuit is formed The connection material was affixed on the surface of the glass substrate with an ITO circuit at 80 ° C. and 0.98 MPa (10 kgf / cm ² ). Thereafter, the separator was peeled off from the film-like circuit connecting material attached to the glass substrate with ITO circuit, and the gold bumps of the chip and the glass substrate with ITO circuit were aligned through the film-like circuit connecting material. Next, the surface on which the gold bumps of the chip are provided is directed to the surface opposite to the surface on which the glass substrate with ITO circuit of the film-like circuit connecting material is attached, and the condition of 190 ° C., 40 g / bump, 10 seconds. Then, heating and pressurization were performed to make this connection, and a connected body sample was obtained.

(Example 2)
Instead of a dispersion containing 40% by mass of silica filler 1 (35 g) based on the total amount of the adhesive component, a dispersion containing 10% by mass of silica filler 1 (9 g) based on the total amount of the adhesive component is added. A film-like circuit connecting material was produced in the same manner as in Example 1 except that.

(Example 3)
Instead of a dispersion containing 40% by mass of silica filler 1 (35 g) based on the total amount of the adhesive component, a dispersion containing 40% by mass of silica filler 2 (35 g) based on the total amount of the adhesive component is added. A film-like circuit connecting material was produced in the same manner as in Example 1 except that.

Example 4
Insulating coated conductive particles having an average particle size of 6.0 μm instead of insulating coated conductive particles having an average particle size of 3.0 μm (particles in which colloidal silica is coated on nickel-plated and gold-plated plastic particles) A film-like circuit connection material was prepared in the same manner as in Example 1 except that conductive particles obtained by nickel-plating and gold-plating plastic particles were coated with colloidal silica.

(Comparative Example 1)
Instead of a dispersion containing 40% by mass of silica filler 1 (35 g) based on the total amount of the adhesive component, a dispersion containing 40% by mass of silica filler 4 (35 g) based on the total amount of the adhesive component is added. A film-like circuit connecting material was produced in the same manner as in Example 1 except that.

(Comparative Example 2)
Instead of a dispersion containing 40% by mass of silica filler 1 (35 g) based on the total amount of the adhesive component, a dispersion containing 40% by mass of silica filler 3 (35 g) based on the total amount of the adhesive component is added. A film-like circuit connecting material was produced in the same manner as in Example 1 except that.

(Comparative Example 3)
Instead of a dispersion containing 40% by mass of silica filler 1 (35 g) based on the total amount of the adhesive component, a dispersion containing 5% by mass of silica filler 1 (4.5 g) based on the total amount of the adhesive component A film-like circuit connecting material was produced in the same manner as in Example 1 except that was added.

[Test results]
The following tests were conducted on the film-like circuit connecting material obtained by the above production method. The results are shown in Tables 2 and 3.

(Connection resistance value)
The connection resistance of the connection body sample was measured by the 4-terminal method. The measurement device uses R-6145 (trade name) manufactured by Advantest Co., Ltd. as a constant current power supply device, and applies a constant current (1 mA) between the chip electrode and the substrate electrode. It was measured using a digital multimeter (trade name: R-6557) manufactured by Advantest Co., Ltd. and converted into a resistance value. A connection sample having a connection resistance value of less than 5Ω was evaluated as good.

(Average value and variation of particle capture rate)
Using a chip (size: 2.0 mm x 15.3 mm) composed of gold bumps of 30 µm x 100 µm, a connected sample using a high-definition automatic bonder (trade name: FC-1200) manufactured by Toray Engineering Co., Ltd. A test body mounted with was prepared. The conductive particles captured on 100 gold bumps were counted, and the average value and variation (CV) of the particle capture rate were obtained. Here, the particle capture rate means the ratio of the number of conductive particles remaining on the electrode to the total number of conductive particles in the circuit connecting material, and [particle capture rate (%)] = captured on a bump having a certain area. The number of particles to be obtained / the number of particles existing in a certain area × 100.

(Film formability)
Use a microscope to observe coating scratches, white spots, and cracks in the coated film when coating circuit connection materials that have been blended. Peeling was performed using a STA-1150 measuring machine manufactured by KK, and the tack force was measured. Based on the obtained results, the film formability was evaluated in the following manner.
A: There are no coating scratches, white spots, and film cracks, and a high tack force (25 kgf or more).
C: The occurrence of coating scratches, white spots, or cracks in the film, or a decrease in tack force (less than 10 kgf).

(Insulation resistance value)
A voltage of direct current (DC) 50V was applied to the connection part of the circuit for 1 minute, and the insulation resistance after the application was measured with a multimeter using a two-terminal measurement method. For the insulation resistance of the COG connection body, an insulation resistance measurement part of a test body having a distance between adjacent electrodes of 10 μm was used. An insulation resistance measuring machine (trade name: TR8611A) manufactured by Advantest Co., Ltd. was used as a measuring instrument, and the insulation resistance value after application of DC 50 V for 30 seconds was measured for a plurality of circuits in a lump between the electrodes.

(Monodispersion rate of conductive particles)
A laminate of the adhesive layer and the conductive particle layer was cut into a 1 mm square, while a separately prepared adhesive layer alone was cut into a 3 mm square. Each of these was placed on a cover glass and bonded together, and then rolled for 40 seconds at 80 ° C. using a high-definition automatic bonder (trade name: FC-1200) manufactured by Toray Engineering Co., Ltd. Heated and pressurized in seconds. An image was taken at 1000 times using an optical microscope (trade name: VH-Z450) manufactured by Keyence, and the monodispersity of the conductive particles was measured. Here, the conductive particle layer means a layer having anisotropic conductive characteristics in which varnish and conductive particles are blended. The monodispersion rate of the conductive particles means the ratio of the conductive particles that are present alone in the entire conductive particles, and is represented by the following formula. [Monodispersion rate of conductive particles (%)] = (number of single particles / number of measured particles × 100).

(Water absorption)
1 g of anisotropic conductive adhesive (circuit connection material) is immersed in pure water, left for 1 hour, then dried in a dry oven at 70 ° C. for 3 minutes, and compared before and after immersion, and evaluated as follows. did.
A: Weighing difference before and after soaking + less than 100 mg B: Weighing difference before and after soaking +100 to 300 mg
C: Difference in weighing before and after immersion + over 300mg

  In Examples 1 to 4, the connection resistance value was less than 5Ω, which was a good result, whereas in Comparative Examples 1 to 3, it was revealed that the connection resistance value was 5Ω or more. Thus, the circuit connection material according to the present invention exhibits a sufficiently low connection resistance value, and can be sufficiently used for a circuit member having a narrowed electrode.

DESCRIPTION OF SYMBOLS 1 ... Film-like circuit connection material, 1a ... Circuit connection member, 3 ... Resin composition layer containing silica filler and adhesive component, 5 ... Conductive particle, 10 ... First circuit member, 11 ... First circuit A board, 13 ... 1st circuit electrode, 20 ... 2nd circuit member, 21 ... 2nd circuit board, 23 ... 2nd circuit electrode, 101 ... Connection body of a circuit member.

Claims (13)

(A) a silica filler having an average particle diameter of 3 to 100 nm that has been subjected to a hydrophobization treatment;
(B) an adhesive component;
(C) conductive particles;
A circuit connection material containing 10 to 60% by mass of the silica filler with respect to the total amount of the adhesive component. (A) a silica filler having an average particle diameter of 3 to 100 nm that has been subjected to a hydrophobization treatment;
(B) an adhesive component;
(C) conductive particles;
A circuit connecting material containing 5 to 30% by volume of the silica filler with respect to the total amount of the adhesive component.   The circuit connection material according to claim 1, wherein the amount of the silica filler is 10 to 40% by mass.   The circuit connection material according to claim 2, wherein the amount of the silica filler is 5 to 20% by volume.   The circuit connection material according to any one of claims 1 to 4, wherein the silica filler has an average particle size of 5 to 50 nm.   The circuit connection material according to any one of claims 1 to 4, wherein the silica filler has an average particle size of 5 to 15 nm.   The circuit connecting material according to any one of claims 1 to 6, wherein the silica filler is subjected to a hydrophobizing treatment by attaching or bonding silicone oil thereto.   The circuit connection material according to any one of claims 1 to 7, wherein the silica filler has a carbon content of 3 to 10% by mass.   The circuit connection material according to claim 1, wherein (average particle diameter of the conductive particles) / (average particle diameter of the silica filler) = 20 to 400.   The circuit connection material according to claim 1, wherein the monodispersion rate of the conductive particles is 80% or more. The circuit connection material as described in any one of Claims 1-10 used in order to connect the circuit member which has an electrode of the area of 3000 micrometers ² or less, and another circuit member.   The circuit connection material as described in any one of Claims 1-11 used in order to connect the circuit member which has the some electrode arrange | positioned at intervals of 12 micrometers or less, and another circuit member. A first circuit member having a first electrode;
Hardened | cured material which the circuit connection material as described in any one of Claims 1-12 hardened,
A second circuit member having a second electrode;
In this order,
A connection member for a circuit member, wherein the first circuit member and the second circuit member are arranged and connected so that the first electrode and the second electrode face each other.

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