JP5029372B2 - Anisotropic conductive adhesive, anisotropic conductive film, and method for manufacturing circuit connection structure - Google Patents

Description

  The present invention relates to an anisotropic conductive adhesive, an anisotropic conductive film, and a method for manufacturing a circuit connection structure.

  Conventionally, conductive particles are dispersed in an adhesive to connect a liquid crystal display and TCP (Tape Carrier Package) or FPC (Flexible Printed Circuits) and TCP, and to connect an FPC and a printed wiring board. An anisotropic conductive adhesive is used. Among such anisotropically conductive adhesives, for example, epoxy resin adhesives are excellent in workability, but are usually heated at a connection time of about 20 seconds at about 140 to 180 ° C. and at 10 seconds at 180 to 210 ° C. Some degree of heating is required.

In recent years, in the field of anisotropic conductive adhesives, there has been a demand for shortening the connection time to 10 seconds or less in order to improve production efficiency, and radical curing type anisotropic conductivity with excellent low-temperature fast curing properties. Adhesives have been studied (see Patent Document 1).
International Publication No. 98/44067 Pamphlet

  However, in the case of the conventional radical curable anisotropic conductive adhesive, it is difficult to determine when there is a variation in the connection temperature compared to the conventional epoxy curable adhesive. It is not always easy to obtain a stable force, and there is still room for improvement in connection reliability.

  The present invention has been made in view of such circumstances, and at the time of electrically connecting the circuit electrodes of two circuit members disposed opposite to each other, the low-temperature fast curing property and the connection reliability are at a high level. An anisotropic conductive adhesive and an anisotropic conductive film that can be compatible, and a method for manufacturing a circuit connection structure using the anisotropic conductive adhesive or the anisotropic conductive film are provided. Objective.

  As a result of intensive studies to solve the above-mentioned problems, the present inventor has insufficient connection reliability in the case of conventional radical-curing anisotropic conductive adhesives because of the hue associated with the progress of the curing reaction. It was found that there was no change and it was very difficult to visually determine whether the curing reaction had progressed sufficiently. As a result of further investigation based on such knowledge, the inventors found that the above-mentioned problems can be solved by using an anisotropic conductive adhesive whose hue is changed by heating or radical reaction of contained components, thereby completing the present invention. It came.

  That is, the present invention provides a first circuit member in which a first circuit electrode is formed on a main surface of a first substrate, and a second circuit electrode in which a second circuit electrode is formed on a main surface of a second substrate. Pressurizing and heating the second circuit member with the first circuit electrode and the second circuit electrode facing each other to electrically connect the first circuit electrode and the second circuit electrode An anisotropic conductive adhesive, which is a radical curable anisotropic conductive agent that changes its hue by a radical reaction of contained components.

  According to the above anisotropic conductive adhesive of the present invention, it is possible to easily determine whether the curing reaction has sufficiently progressed or not by changing the hue. Sufficient connection resistance and adhesive strength can be stably obtained while effectively exhibiting the low-temperature fast curing property of

  The anisotropic conductive adhesive of the present invention preferably contains a radical polymerizable substance, a radical polymerization initiator, and an additive whose hue changes by a radical reaction.

  Moreover, it is preferable that the anisotropic conductive adhesive of this invention further contains electroconductive particle.

  In the anisotropic conductive adhesive of the present invention, the additive whose hue changes by radical reaction is an aromatic ketone compound (including anthraquinone, acetophenone, etc.), 1,1-diphenyl-2-picrylhydra It is preferably at least one selected from the group consisting of zil, azobenzene, fulgides, diarylethene, and spirooxazine compounds. In addition, since the reaction between the radical polymerization initiator and the radical polymerizable substance is not easily inhibited, the content of the additive whose hue changes due to the radical reaction is 0 based on the total weight of the anisotropic conductive adhesive. It is preferably 0.05 to 5% by weight.

  The present invention also provides an adhesive film for circuit connection formed by forming the anisotropic conductive adhesive of the present invention into a film shape.

  The adhesive film for circuit connection of the present invention is formed by forming the anisotropic conductive adhesive of the present invention into a film shape, and it is easily determined whether or not the curing reaction has proceeded sufficiently by changing the hue. Is something that can be done. Therefore, according to the adhesive film for circuit connection of the present invention, it is possible to stably exhibit sufficient connection resistance and adhesive force while effectively exhibiting the low-temperature fast-curing property inherent in the radical curable anisotropic conductive adhesive. Can be obtained.

  The present invention also provides a first circuit member in which a first circuit electrode is formed on a main surface of a first substrate, and a second circuit electrode in which a second circuit electrode is formed on a main surface of a second substrate. The second circuit member is added with the first circuit electrode and the second circuit electrode facing each other through the anisotropic conductive adhesive of the present invention or the anisotropic conductive film of the present invention. Provided is a method for manufacturing a circuit connection structure including a step of pressure and heating to electrically connect a first circuit electrode and a second circuit electrode.

  According to the method for producing a circuit connection structure of the present invention, since it is possible to easily determine whether the curing reaction has sufficiently progressed or not by changing the hue, the radical curable anisotropic conductive adhesive is inherently In addition, it is possible to stably impart sufficient connection resistance and adhesive force to the obtained circuit connection structure while effectively exhibiting the low-temperature fast curing property.

  As described above, according to the present invention, when electrically connecting the circuit electrodes of two circuit members arranged opposite to each other, it is possible to achieve both a low-temperature rapid curing property and connection reliability at a high level. An anisotropic conductive adhesive and an anisotropic conductive film, and a method of manufacturing a circuit connection structure using the anisotropic conductive adhesive are provided.

  Hereinafter, preferred embodiments of the present invention will be described in detail. In the present invention, “(meth) acrylic resin” means “acrylic resin” and its corresponding “methacrylic resin”, and “(meth) acrylic acid” means “acrylic acid” and its corresponding “methacrylic resin”. “Acid” means “(meth) acrylate” means “acrylate” and its corresponding “methacrylate”, “(meth) acryloyl” means “acryloyl” and its corresponding “methacryloyl”, “(Meth) acryloxy” means “acryloxy” and the corresponding “methacryloxy”.

(Anisotropic conductive adhesive)
The anisotropic conductive adhesive of the present invention is a radical curable anisotropic conductive agent whose hue changes due to the radical reaction of the contained components, preferably by a radical polymerizable substance, a radical polymerization initiator, and a radical reaction. And an additive that changes hue.

  Examples of the radical polymerizable substance (also referred to as “radical curable substance” or “radical polymerizable compound”) include monomers constituting (meth) acrylic resin, maleimide resin, citraconic imide resin, and the like. These radically polymerizable substances may be used alone or in combination of two or more.

  Monomers constituting the (meth) acrylic resin include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, isobutyl (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate , Trimethylolpropane tri (meth) acrylate, tetramethylene glycol tetra (meth) acrylate, 2-hydroxy-1,3-diaacryloxypropane, 2,2-bis [4- (acryloxymethoxy) phenyl] propane, 2 , 2-bis [4- (acryloxyethoxy) phenyl] propane, dicyclopentenyl (meth) acrylate tricyclodecanyl (meth) acrylate, tris (acryloxyethyl) isocyanurate, urethane (meta Acrylate and the like. These monomers may be used individually by 1 type, and may be used in combination of 2 or more types. Moreover, you may use radical polymerization inhibitors, such as hydroquinone and methyl ether hydroquinone, in the range by which sclerosis | hardenability is not impaired as needed.

  Furthermore, when a radically polymerizable substance having a phosphate ester structure is used, it is possible to improve the adhesion to inorganic substances such as metals. The radically polymerizable substance having a phosphoric ester structure is obtained as a reaction product of phosphoric anhydride and a monomer such as 2-hydroxyethyl (meth) acrylate. Specific examples include mono (2-methacryloyloxyethyl) acid phosphate, di (2-methacryloyloxyethyl) acid phosphate, and the like. One radically polymerizable substance having a phosphate ester structure may be used alone, or two or more kinds may be used in combination.

  The monomer constituting the maleimide resin has at least one maleimide group in the molecule. For example, phenylmaleimide, 1-methyl-2,4-bismaleimidebenzene, N, N′-m-phenylene Bismaleimide, N, N′-p-phenylenebismaleimide, N, N′-4,4-biphenylenebismaleimide, N, N′-4,4- (3,3-dimethylbiphenylene) bismaleimide, N, N '-4,4- (3,3-dimethyldiphenylmethane) bismaleimide, N, N'-4,4- (3,3-diethyldiphenylmethane) bismaleimide, N, N'-4,4-diphenylmethane bismaleimide, N, N′-4,4-diphenylpropane bismaleimide, N, N′-4,4-diphenyl ether bismaleimide, N, N′-4 4-diphenylsulfone bismaleimide, 2,2-bis (4- (4-maleimidophenoxy) phenyl) propane, 2,2-bis (3-s-butyl-3,4- (4-maleimidophenoxy) phenylpropane, 1,1-bis (4- (4-maleimidophenoxy) phenyl) decane, 4,4′-cyclohexylidene-bis (1- (4-maleimidophenoxy) phenoxy) -2-cyclohexylbenzene, 2,2-bis (4- (4-maleimidophenoxy) phenyl) hexafluoropropane, etc. These monomers may be used alone or in combination of two or more.

  The monomer constituting the citraconic imide resin has at least one citraconic imide group in the molecule. For example, phenyl citraconic imide, 1-methyl-2,4-bis citraconic imide benzene, N, N ′ -M-phenylene biscitraconimide, N, N'-p-phenylene biscitraconimide, N, N'-4,4-biphenylene biscitraconimide, N, N'-4,4- (3,3-dimethylbiphenylene ) Biscitraconimide, N, N′-4,4- (3,3-dimethyldiphenylmethane) biscitraconimide, N, N′-4,4- (3,3-diethyldiphenylmethane) biscitraconimide, N, N '-4,4-diphenylmethane biscitraconimide, N, N'-4,4-diphenylpropane biscitracon N, N′-4,4-diphenyl ether biscitraconimide, N, N′-4,4-diphenylsulfone biscitraconimide, 2,2-bis (4- (4-citraconimidophenoxy) phenyl) propane, 2,2-bis (3-s-butyl-3,4- (4-citraconimidophenoxy) phenyl) propane, 1,1-bis (4- (4-citraconimidophenoxy) phenyl) decane, 4,4 ′ -Cyclohexylidene-bis (1- (4-citraconimidophenoxy) phenoxy) -2-cyclohexylbenzene, 2,2-bis (4- (4-citraconimidophenoxy) phenyl) hexafluoropropane and the like. These monomers may be used individually by 1 type, and may be used in combination of 2 or more type.

  The blending amount of the radical polymerizable substance is preferably 5 to 70% by weight, more preferably 10 to 50% by weight, based on the total weight of the anisotropic conductive adhesive, from the viewpoint of maintaining the connection at the time of curing.

  The radical polymerization initiator (also referred to as “curing agent that generates free radicals upon heating” or “free radical generator”) is not particularly limited as long as it is a compound that generates radicals by heat or light. A peroxide is mentioned. The radical polymerization initiator is appropriately selected in consideration of the intended connection temperature, connection time, storage stability, and the like. In order to suppress corrosion of the connection terminals of the circuit member, the chlorine ion or organic acid contained in the radical polymerization initiator is preferably 5000 ppm or less, and further, those that generate less organic acid after thermal decomposition. More preferred. Moreover, since the stability of the produced anisotropically conductive adhesive improves, it is preferable to have a weight retention of 20% by weight or more after being left open for 24 hours at room temperature (25 ° C.) and normal pressure.

  Specific examples of the peroxide as the radical polymerization initiator include diacyl peroxide, peroxydicarbonate, peroxyester, peroxyketal, dialkyl peroxide, hydroperoxide, silyl peroxide, and the like. Peroxyesters, dialkyl peroxides, hydroperoxides, and silyl peroxides contain 5000 ppm or less of chlorine ions and organic acids in the initiator, and are less likely to be generated after heat decomposition, and can be made of metals. It is particularly preferable because corrosion of connection terminals of circuit members can be suppressed.

  Diacyl peroxides include isobutyl peroxide, 2,4-dichlorobenzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, succinic peroxide, Examples include benzoyl peroxytoluene and benzoyl peroxide.

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

  Peroxyesters include cumylperoxyneodecanoate, 1,1,3,3-tetramethylbutylperoxyneodecanoate, 1-cyclohexyl-1-methylethylperoxynoedecanoate, t- Hexyl peroxyneodecanoate, t-butyl peroxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanate, 2,5-dimethyl-2,5-di (2 -Ethylhexanoylperoxy) hexane, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexa Nonate, t-butylperoxyisobutyrate, 1,1-bis (t-butylperoxy) cyclohexane t-hexylperoxyisopropyl monocarbonate, t-butylperoxy-3,5,5-trimethylhexanate, t-butylperoxylaurate, 2,5-dimethyl-2,5-di (m-toluoyl) Peroxy) hexane, t-butyl peroxyisopropyl monocarbonate, t-butyl peroxy-2-ethylhexyl monocarbonate, t-hexyl peroxybenzoate, t-butyl peroxyacetate and the like.

  In peroxyketals, 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-hexylperoxy) cyclohexane, 1,1-bis (t- Butyl peroxy) -3,3,5-trimethylcyclohexane, 1,1- (t-butylperoxy) cyclododecane, 2,2-bis (t-butylperoxy) decane and the like.

  Dialkyl peroxides include α, α′-bis (t-butylperoxy) diisopropylbenzene, dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, and t-butyl. Cumyl peroxide and the like.

  Examples of hydroperoxides include diisopropylbenzene hydroperoxide and cumene hydroperoxide.

  Examples of silyl peroxides include t-butyltrimethylsilyl peroxide, bis (t-butyl) dimethylsilyl peroxide, t-butyltrivinylsilyl peroxide, bis (t-butyl) divinylsilyl peroxide, and tris (t-butyl). ) Vinylsilyl peroxide, t-butyltriallylsilyl peroxide, bis (t-butyl) diallylsilyl peroxide, tris (t-butyl) allylsilyl peroxide, and the like.

  A radical polymerization initiator may be used individually by 1 type, and may be used in combination of 2 or more type. Furthermore, you may combine a decomposition accelerator or a decomposition inhibitor with a radical polymerization initiator. In addition, the radical polymerization initiator may be used after being coated with a polymer material such as polyurethane or polyester and microencapsulated. A microencapsulated product is preferred because the pot life is extended.

  The blending amount of the radical polymerization initiator is preferably 1 to 20% by weight and more preferably 2 to 15% by weight based on the total weight of the anisotropic conductive adhesive from the viewpoint of the reaction rate of the curing reaction.

  Additives that change hue by radical reaction include aromatic ketone compounds such as anthraquinone and acetophenone, 1,1-diphenyl-2-picrylhydrazyl, azobenzene, fulgides, diarylethene, spirooxazine compounds, etc. Anthraquinone compounds with less adverse effects that inhibit the reaction between the radical polymerization initiator and the radical polymerizable substance are preferred.

  The blending amount of the additive whose hue changes due to the radical reaction is preferably 0.01 to 10% by weight based on the total weight of the anisotropic conductive adhesive since the change in hue can be easily determined. 0.1 to 1% by weight is particularly preferred because the adverse effect of inhibiting the reaction can be further reduced.

  The additive whose hue is changed by a radical reaction is preferably an additive capable of causing a hue change when the anisotropic conductive adhesive is heated at 130 ° C. to 200 ° C. for about 5 seconds. 1,1-diphenyl-2-picrylhydrazyl is preferred as long as the adverse effect of hindering the reaction between and the radically polymerizable substance is small.

  The anisotropic conductive adhesive of the present invention may be composed only of a radical polymerizable substance, a radical polymerization initiator, and an additive whose hue changes due to a radical reaction, but film formability, adhesiveness In order to impart stress relaxation during curing, a polymer component can be further contained. Examples of the polymer resin component include polyvinyl butyral resin, polyester resin, polyamide resin, polyimide resin, phenoxy resin, polyurethane resin, and acrylic rubber. The weight average molecular weight of the polymer component is preferably 10,000 to 10,000,000. The polymer component may be modified with a radical polymerizable functional group, and in this case, the heat resistance is improved. The blending amount of the polymer component is preferably 2 to 80% by weight, more preferably 5 to 70% by weight, and particularly preferably 10 to 60% by weight based on the total weight of the anisotropic conductive adhesive. If it is less than 2% by weight, the stress relaxation and the adhesive force are not sufficient, and if it exceeds 80% by weight, the fluidity is lowered.

  Moreover, the anisotropic conductive adhesive of this invention may further contain additives, such as a filler, a softening agent, an accelerator, an antiaging agent, a flame retardant, and a coupling agent, as needed.

  Even if the anisotropic conductive adhesive of the present invention does not contain conductive particles, electrical connection can be obtained by direct contact between the opposing electrodes at the time of connection. The electrical connection between the electrodes can be performed more stably. As conductive particles, metal particles such as Au, Ag, Ni, Cu, solder, etc., carbon, or non-conductive particles such as glass, ceramic, plastic, etc., coated with noble metals such as Au, Ag, platinum are used. Is done. In the case of metal particles, those coated with noble metals are preferred in order to suppress surface oxidation. Among the above conductive particles, particles coated with Au, Ag, etc. with plastic as the core and hot-melt metal particles are deformed by heating and pressurization during connection, increasing the contact area, and variations in the height of the connection electrodes. To improve reliability. If the thickness of the noble metal coating layer is preferably 100 mm or more, more preferably 300 mm or more, good connection can be obtained. Furthermore, the above conductive particles coated with an insulating resin can also be used. The conductive particles are appropriately blended depending on the application in the range of preferably 0.1 to 30% by volume, more preferably 0.1 to 10% by volume with respect to 100% by volume of the adhesive component.

  The anisotropic conductive adhesive of the present invention can be used in the form of a paste when it is liquid at room temperature. In the case of a solid at normal temperature, it can be made into a paste using a solvent in addition to being made into a paste by heating. The solvent that can be used is not particularly limited as long as it does not react with the anisotropic conductive adhesive and exhibits sufficient solubility, but a solvent having a boiling point of 50 to 150 ° C. at normal temperature is preferable. When the boiling point of the solvent is less than 50 ° C., the solvent easily volatilizes at room temperature, and the workability when producing a film described later tends to deteriorate. Moreover, when the boiling point of a solvent exceeds 150 degreeC, it will become difficult for a solvent to volatilize and it exists in the tendency for the adhesive strength after adhesion | attachment to fall with the remaining solvent.

  The anisotropic conductive adhesive of the present invention can also be used in the form of a film (that is, an anisotropic conductive film). Thus, when the anisotropic conductive adhesive is in the form of a film, it is excellent in handleability and more convenient. This anisotropic conductive film is prepared by, for example, applying a mixed liquid obtained by adding a solvent to an anisotropic conductive adhesive onto a peelable substrate such as a fluororesin film, a polyethylene terephthalate film, or a release paper, or a nonwoven fabric or the like. It can be obtained by impregnating the base material with the above mixed solution and placing it on a peelable base material and removing the solvent.

  According to the anisotropic conductive adhesive and the anisotropic conductive film of the present invention, the electrodes can be bonded and electrically connected by being placed between opposing electrodes on the substrate, and heated and pressurized. And the anisotropic conductive adhesive and anisotropic conductive film of this invention enable coexistence with low-temperature quick curing property and connection reliability, for example, when heating temperature is 130-200 degreeC. Connection time can be reduced to 10 seconds or less. Here, the heating temperature is more preferably 150 to 180 [deg.] C. from the viewpoint of achieving both low temperature fast curability and connection reliability. Moreover, the pressure should just be the range which does not damage an adherend, and generally 1-10 Mpa is preferable. Moreover, you may perform postcure as needed. Furthermore, at the time of connection, in addition to heating and pressing, energy other than heat (light, ultrasonic waves, electromagnetic waves, etc.) may be used as necessary.

  Since the anisotropic conductive adhesive and anisotropic conductive film of the present invention have the above-described excellent characteristics, they can be suitably used as a circuit connection material. For example, when the circuit electrode of the first circuit member and the second circuit member are electrically connected, the two circuit members are arranged to face each other via the anisotropic conductive adhesive or anisotropic conductive film of the present invention. By applying pressure and heating in such a state, a curing reaction by radical polymerization proceeds and can be electrically connected to the other circuit electrode. And since it can be easily determined whether the curing reaction has sufficiently progressed due to the change in hue of the anisotropic conductive adhesive or anisotropic conductive film, the connection reliability and low-temperature rapid curing in the resulting circuit connection structure It becomes possible to balance with sex.

(Circuit member connection structure)
Next, a preferred example of a circuit member connection structure obtained using the anisotropic conductive adhesive and anisotropic conductive film of the present invention will be described. FIG. 1 is a schematic cross-sectional view showing an example of a connection structure of the circuit member. As shown in FIG. 1, the circuit member connection structure 1 includes a first circuit member 20 and a second circuit member 30 that face each other, and the first circuit member 20 and the second circuit member 30. Between the two, a circuit connecting member 10 for electrically connecting them is provided. The first circuit member 20 includes a first circuit board 21 and a first circuit electrode 22 formed on the main surface 21 a of the circuit board 21. Note that an insulating layer (not shown) may be formed on the main surface 21a of the circuit board 21 in some cases.

  On the other hand, the second circuit member 30 includes a second circuit board 31 and a second circuit electrode 32 formed on the main surface 31 a of the second circuit board 31. In addition, an insulating layer (not shown) may be formed on the main surface 31a of the circuit board 31 according to circumstances.

The first circuit member 20 and the second circuit member 30 are not particularly limited as long as electrodes that require electrical connection are formed, but at least one electrode height is 5 to 14 μm. It is preferable. Specific examples include glass or plastic substrates on which electrodes are formed of ITO or the like used for liquid crystal displays, printed wiring boards, ceramic wiring boards, flexible wiring boards, semiconductor silicon chips, TCP, two-layer FPC, etc. These can be used in combination as needed. As described above, in the present embodiment, a material made of an organic material such as a printed wiring board or polyimide, a metal such as copper or aluminum, ITO (indium tin oxide), silicon nitride (Si _x N _y ), silicon dioxide (SiO 2). Circuit members having various surface states such as inorganic materials such as ₂ ) can be used.

  The circuit connection member 10 is formed using the anisotropic conductive adhesive or anisotropic conductive film of the present invention, and contains an insulating substance 11 and conductive particles 7. The conductive particles 7 are disposed not only between the first circuit electrode 22 and the second circuit electrode 32 facing each other but also between the main surfaces 21a and 31a. In the circuit member connection structure 1 of the present embodiment, the first circuit electrode 22 and the second circuit electrode 32 are electrically connected via the conductive particles 7. For this reason, the connection resistance between the first circuit electrode 22 and the second circuit electrode 32 is sufficiently reduced. Therefore, the flow of current between the first circuit electrode 22 and the second circuit electrode 32 can be made smooth, and the functions of the circuit can be sufficiently exhibited. Moreover, it is also possible to show the anisotropy of electrical connection by setting the conductive particles 7 to the above-described mixing ratio.

  In addition, when the circuit connection member 10 does not contain the conductive particles 7, they are directly contacted so that a desired amount of current flows between the first circuit electrode 22 and the second circuit electrode 32. It is electrically connected by making it close or sufficiently close.

  Since the circuit connection member 10 is formed using the anisotropic conductive adhesive or anisotropic conductive film of the present invention, the first circuit electrode 22 and the first circuit electrode 22 can be formed even when the connection time is shortened. The long-term reliability of the electrical characteristics between the two circuit electrodes 32 can be ensured. That is, the adhesive strength of the circuit connection member 10 to the first circuit member 20 or the second circuit member 30 is sufficiently high, the connection resistance is sufficiently low, and this state can be maintained for a long period of time.

(Method for manufacturing circuit member connection structure)
Next, a method for manufacturing the circuit member connection structure described above will be described with reference to FIG.

  First, the first circuit member 20 and the film-like circuit connecting material 40 described above are prepared (see FIG. 2A). In this embodiment, as the film-like circuit connecting material 40, an anisotropic conductive adhesive of the present invention formed into a film (that is, the anisotropic conductive film of the present invention) is applied. The circuit connection material contains an adhesive component 5 and conductive particles 7. Here, the adhesive component according to the present invention described above is used for the adhesive component 5. Even when the circuit connecting material does not contain the conductive particles 7, the circuit connecting material can be used for anisotropic conductive bonding as an insulating adhesive, and is sometimes called NCA (Non-Conductive Adhesive). When the circuit connecting material contains conductive particles 7, the circuit connecting material may be called ACA (Anisotropic Conductive Adhesive).

  The thickness of the film-like circuit connecting material 40 is preferably 10 to 50 μm. If the thickness of the film-like circuit connecting material 40 is less than 10 μm, the circuit connecting material tends to be insufficiently filled between the circuit electrodes 22 and 32. On the other hand, if the thickness exceeds 50 μm, the anisotropic conductive adhesive between the circuit electrodes 22 and 32 cannot be sufficiently removed, and it tends to be difficult to ensure conduction between the circuit electrodes 22 and 32.

  Next, the film-like circuit connecting material 40 is placed on the surface of the first circuit member 20 on which the circuit electrodes 22 are formed. When the film-like circuit connecting material 40 is attached on a support (not shown), the film-like circuit connecting material 40 side is directed to the first circuit member 20 so that the first circuit is connected. Place on member 20. At this time, the film-like circuit connecting material 40 is film-like and easy to handle. For this reason, the film-like circuit connecting material 40 can be easily interposed between the first circuit member 20 and the second circuit member 30, and the first circuit member 20 and the second circuit member 30 Connection work can be performed easily.

  And the film-form circuit connection material 40 is pressurized to the arrow A and B direction of Fig.2 (a), and the film-form circuit connection material 40 is temporarily connected to the 1st circuit member 20 (refer FIG.2 (b)). . At this time, you may pressurize, heating. However, the heating temperature is set to a temperature at which the anisotropic conductive adhesive or the anisotropic conductive film constituting the film-like circuit connecting material 40 is not cured, that is, a temperature lower than the temperature at which the radical polymerization initiator generates free radicals.

  Subsequently, as shown in FIG. 2 (c), the second circuit member 30 is placed on the film-like circuit connection material 40 with the second circuit electrode facing the first circuit member 20. In addition, when the film-form circuit connection material 40 has adhered on the support body (not shown), after peeling a support body, the 2nd circuit member 30 is mounted on the film-form circuit connection material 40. FIG.

  And it heats through the 1st and 2nd circuit members 20 and 30 to the arrow A and B direction of FIG.2 (c), heating the film-form circuit connection material 40. FIG. The heating temperature at this time is set to a temperature at which the radical polymerization initiator contained in the film-like circuit connecting material 40 can generate free radicals. Thereby, free radicals are generated in the radical polymerization initiator, and polymerization of the radical polymerizable substance is started. In this way, the film-like circuit connection material 40 is cured and the main connection is performed, and a circuit member connection structure as shown in FIG. 1 is obtained.

  Although heating temperature is suitably selected by the use to be used, an anisotropic conductive adhesive, and a circuit member, 130-200 degreeC is preferable and 150-170 degreeC is more preferable from a viewpoint of low-temperature fast-curing property. Even when it is determined that the curing reaction has sufficiently progressed due to the change in hue, after-curing may be performed as necessary.

  When the circuit member connection structure is manufactured as described above, in the circuit member connection structure obtained, the conductive particles 7 can be brought into contact with both of the circuit electrodes 22 and 32 facing each other. The connection resistance between 32 can be sufficiently reduced.

  Further, by heating the film-like circuit connecting material 40, the adhesive component 5 is cured to become the insulating substance 11 in a state where the distance between the circuit electrode 22 and the circuit electrode 32 is sufficiently small, and the first circuit member is obtained. 20 and the second circuit member 30 are firmly connected via the circuit connection member 10. That is, in the obtained circuit member connection structure, since the circuit connection member 10 is formed of a cured product of the circuit connection material containing the anisotropic conductive adhesive, the circuit connection member for the circuit member 20 or 30 is used. 10 is sufficiently high, and the connection resistance between the circuit electrodes 22 and 32 can be sufficiently reduced. The circuit member connection structure can maintain such a state for a long period of time. Therefore, the circuit member connection structure obtained is excellent in the long-term reliability of the electrical characteristics between the circuit electrodes 22 and 32.

  The adhesive component 5 may include at least a radical polymerization initiator that generates radicals by heating. Instead of this radical polymerization initiator, a radical polymerization initiator that generates radicals only by light irradiation may be used. Good. In this case, when the film-like circuit connecting material 40 is cured, light irradiation may be performed instead of heating. In addition, a radical polymerization initiator that generates radicals by ultrasonic waves, electromagnetic waves, or the like may be used as necessary. Moreover, you may use an epoxy resin and a latent hardener as a sclerosing | hardenable component in the adhesive agent component 5. FIG.

  Moreover, in the said embodiment, although the connection structure of a circuit member is manufactured using the film-form circuit connection material 40, it replaces with the film-form circuit connection material 40, and uses the circuit connection material which is not formed in the film form. May be. Even in this case, if the circuit connection material is dissolved in a solvent and the solution is applied to either the first circuit member 20 or the second circuit member 30 and dried, the first and second circuit members 20 are used. , 30 can interpose a circuit connecting material.

  Further, instead of the conductive particles 7, other conductive materials may be used. Examples of other conductive materials include particulate or short fiber carbon, metal wires such as Au-plated Ni wire, and the like.

(Semiconductor device)
Next, embodiments of the semiconductor device of the present invention will be described. FIG. 3 is a schematic cross-sectional view showing an embodiment of the semiconductor device of the present invention. As shown in FIG. 3, the semiconductor device 2 of the present embodiment includes a semiconductor element 50 and a substrate 60 serving as a semiconductor support member, and these are electrically connected between the semiconductor element 50 and the substrate 60. A semiconductor element connection member 80 is provided to connect to the semiconductor device. The semiconductor element connection member 80 is stacked on the main surface 60 a of the substrate 60, and the semiconductor element 50 is further stacked on the semiconductor element connection member 80.

  The substrate 60 includes a circuit pattern 61, and the circuit pattern 61 is electrically connected to the semiconductor element 50 via the semiconductor connection member 80 on the main surface 60 a of the substrate 60 or directly. And these are sealed with the sealing material 70, and the semiconductor device 2 is formed.

  The material of the semiconductor element 50 is not particularly limited, but silicon, germanium group 4 semiconductor element, GaAs, InP, GaP, InGaAs, InGaAsP, AlGaAs, InAs, GaInP, AlInP, AlGaInP, GaNAs, GaNP, GaInNAs, GaInNP, III-V group compound semiconductor elements such as GaSb, InSb, GaN, AlN, InGaN, InNAsP, II-VI group compound semiconductor elements such as HgTe, HgCdTe, CdMnTe, CdS, CdSe, MgSe, MgS, ZnSe, ZeTe, and Various materials such as CuInSe (ClS) can be used.

  The semiconductor element connection member 80 contains the insulating substance 11 and the conductive particles 7. The conductive particles 7 are disposed not only between the semiconductor element 50 and the circuit pattern 61 but also between the semiconductor element 50 and the main surface 60a. In the semiconductor device 2 of the present embodiment, the semiconductor element 50 and the circuit pattern 61 are electrically connected via the conductive particles 7. For this reason, the connection resistance between the semiconductor element 50 and the circuit pattern 61 is sufficiently reduced. Therefore, the current flow between the semiconductor element 50 and the circuit pattern 61 can be made smooth, and the functions of the semiconductor can be fully exhibited. Moreover, it is also possible to show the anisotropy of electrical connection by setting the conductive particles 7 to the above-described mixing ratio.

  When the semiconductor element connection member 80 does not contain the conductive particles 7, the semiconductor element 50 and the circuit pattern 61 are brought into direct contact with each other so that a desired amount of current flows or sufficiently close to the electric current. Connected.

  The semiconductor element connection member 80 is made of a cured product of an anisotropic conductive adhesive containing the adhesive component. From this, the adhesive strength of the semiconductor element connection member 40 to the semiconductor element 50 and the substrate 60 is sufficiently high, and the connection resistance between the semiconductor element 50 and the circuit pattern 61 can be sufficiently reduced. And this state can be maintained over a long period of time. Therefore, the long-term reliability of the electrical characteristics between the semiconductor element 50 and the substrate 60 can be sufficiently increased.

(Method for manufacturing semiconductor device)
Next, a method for manufacturing the semiconductor device described above will be described.

  First, a substrate 60 on which a circuit pattern 61 is formed and a film-like semiconductor element connecting material are prepared. The film-like semiconductor element connection material is formed by forming a semiconductor element connection material into a film shape. The semiconductor element connecting material contains an adhesive component 5 and conductive particles 7. Here, the adhesive component according to the present invention described above is used for the adhesive component 5.

  The thickness of the film-like semiconductor element connecting material is preferably 10 to 50 μm. If the thickness of the film-like semiconductor element connecting material is less than 10 μm, the semiconductor element connecting material tends to be insufficiently filled between the circuit pattern 61 and the semiconductor element 50. On the other hand, when the thickness exceeds 50 μm, the anisotropic conductive adhesive between the circuit pattern 61 and the semiconductor element 50 cannot be sufficiently removed, and it tends to be difficult to ensure conduction between the circuit pattern 61 and the semiconductor element 50.

  Next, the film-like semiconductor element connecting material is placed on the surface of the substrate 60 on which the circuit pattern 61 is formed. When the film-like semiconductor element connecting material is attached on a support (not shown), the film-like semiconductor element connecting material is placed on the substrate 60 so that the film-like semiconductor element connecting material side faces the substrate 60. At this time, the film-like semiconductor element connecting material is film-like and easy to handle. For this reason, the film-like semiconductor element connecting material can be easily interposed between the substrate 60 and the semiconductor element 50, and the connection work between the substrate 60 and the semiconductor element 50 can be easily performed.

  Then, the film-like semiconductor element connecting material is pressurized, and the film-like semiconductor element connecting material is temporarily connected to the substrate 60. At this time, you may pressurize, heating. However, the heating temperature is a temperature at which the anisotropic conductive adhesive in the film-like semiconductor element connecting material is not cured, that is, a temperature lower than the temperature at which the radical polymerization initiator generates radicals.

  Subsequently, the semiconductor element 50 is placed on the film-like semiconductor element connecting material. In addition, when the film-form semiconductor element connection material has adhered on the support body (not shown), after peeling a support body, the semiconductor element 50 is mounted on a film-form semiconductor element connection material.

  And it pressurizes through the board | substrate 60 and the semiconductor element 50, heating a film-form semiconductor element connection material. The heating temperature at this time is a temperature at which the radical polymerization initiator can generate radicals. As a result, radicals are generated in the radical polymerization initiator, and polymerization of the radical polymerizable substance is started. In this way, the film-like semiconductor element connecting material is cured and the main connection is performed.

  The heating temperature is, for example, 90 to 200 ° C., and the connection time is, for example, 1 second to 10 minutes. These conditions are appropriately selected depending on the intended use, the anisotropic conductive adhesive, and the substrate, and may be post-cured as necessary.

  Next, the semiconductor element is sealed with resin as necessary. At this time, the resin sealing material is formed on the surface of the substrate, but the resin sealing material may also be formed on the surface opposite to the surface of the substrate. Thereby, a semiconductor device as shown in FIG. 3 is obtained.

  When the semiconductor device is manufactured as described above, in the obtained semiconductor device, the conductive particles 7 can be brought into contact with both the circuit pattern 61 and the semiconductor element 50 facing each other, and between the circuit pattern 61 and the semiconductor element 50. Can be sufficiently reduced.

Further, by heating the film-like semiconductor element connecting material, the adhesive component 5 is cured to become the insulating substance 11 in a state where the distance between the circuit pattern 61 and the semiconductor element 50 is sufficiently small, and the substrate 60 and the semiconductor element 50 are firmly connected to each other through the semiconductor element connecting member 80. That is, in the obtained semiconductor device, since the semiconductor element connection member 80 is made of a cured product of the semiconductor element connection material containing the anisotropic conductive adhesive, the semiconductor element connection to the substrate 50 or the semiconductor element 50 is achieved. The adhesive strength of the member 80 is sufficiently high, and the connection resistance between the semiconductor element 50 and the circuit pattern 61 is sufficiently reduced. Further, in this semiconductor device, such a state is maintained for a long time. Therefore, the obtained semiconductor device is sufficiently prevented from changing with time in the distance between the circuit pattern 61 and the semiconductor element 50, and is excellent in long-term reliability of electrical characteristics between the circuit pattern 61 and the semiconductor element 50.

  In the above embodiment, the adhesive component 5 includes at least a radical polymerization initiator that generates radicals by heating. Instead of this radical polymerization initiator, radicals are generated only by light irradiation. A radical polymerization initiator may be used. In this case, light irradiation may be performed in place of heating when the film-like semiconductor element connecting material is cured. In addition, a radical polymerization initiator that generates radicals by ultrasonic waves, electromagnetic waves, or the like may be used as necessary. Moreover, you may use an epoxy resin and a latent hardener as a sclerosing | hardenable component in the adhesive agent component 5. FIG.

  Moreover, in the said embodiment, although the semiconductor device is manufactured using the film-form semiconductor element connection material, it replaces with a film-form semiconductor element connection material, and even if it uses the semiconductor element connection material which is not formed in the film form Good. Even in this case, if the semiconductor element connecting material is dissolved in a solvent and the solution is applied to either the substrate 60 or the semiconductor element 50 and dried, the semiconductor element connecting material is interposed between the substrate 60 or the semiconductor element 50. be able to.

  Further, instead of the conductive particles 7, other conductive materials may be used. Examples of other conductive materials include particulate or short fiber carbon, metal wires such as Au-plated Ni wire, and the like.

  As mentioned above, although preferred embodiment of this invention was described, this invention is not restrict | limited to this.

  EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example and a comparative example, this invention is not limited to a following example at all.

[Production of adhesive]
Example 1
50 g of phenoxy resin (manufactured by Union Carbide Corporation, trade name PKHC, average molecular weight 45,000) was added to toluene (boiling point 110.6 ° C., SP value 8.90) / ethyl acetate (boiling point 77.1 ° C., SP value 9. 10) = 50/50 (weight ratio) was dissolved in a mixed solvent to obtain a solution having a solid content of 40% by weight. To this solution, phosphate ester acrylate (trade name: P2M, manufactured by Kyoeisha Yushi Co., Ltd.) and trihydroxyethyl glycol dimethacrylate (product name: 80 MFA, manufactured by Kyoeisha Yushi Co., Ltd.) as a radical polymerizable substance, The weight ratio was added so that the phenoxy resin / trihydroxyethylglycol dimethacrylate / phosphate ester acrylate = 50/49/1. Furthermore, 2,5-dimethyl-2,5-bis (2-ethylhexanoylperoxy) hexane (trade name: Perhexa 25O, manufactured by Kyoeisha Yushi Co., Ltd.) as a radical polymerization initiator with respect to 100 parts by weight of the resin component in the solution. ), 5 parts by weight of 1,1-diphenyl-2-picrylhydrazyl as an additive that changes color by radical reaction, and 5 parts of Ni powder (average particle size 5 microns) as conductive particles Part by weight was blended and dispersed to obtain a coating solution.

  Next, a PET (polyethylene terephthalate) film having a thickness of 75 μm and surface-treated was prepared. The above coating solution was applied to this PET film and dried with hot air at 70 ° C. for 5 minutes to obtain an anisotropic conductive film having an adhesive layer with a thickness of 35 μm.

  An anisotropic conductive adhesive having an adhesive layer thickness of 35 μm was obtained by applying it to a PET film having a surface treated on one side having a thickness of 80 μm using a coating apparatus and drying with hot air at 70 ° C. for 10 minutes. A simple coating machine (manufactured by Tester Sangyo) was used for coating the coating solution.

[Production of connected body]
(Preparation of connection A)
Using the obtained anisotropic conductive film, a flexible circuit board (FPC) tin-plated on a copper circuit having a line width of 100 μm, a pitch of 200 μm, and a thickness of 18 μm, and a copper circuit having a line width of 100 μm, a pitch of 200 μm, and a thickness of 35 μm A circuit board (PCB) plated and partly connected with through-holes was connected over a width of 2 mm by heating and pressurizing at 160 ° C. (through-hole part 140 ° C.) and 3 MPa for 5 seconds. At this time, after adhering the adhesive surface of the anisotropic conductive film on one PCB in advance, heating and pressurizing at 70 ° C. and 1 MPa for 2 seconds, and then temporarily connecting the PET film to the other The circuit was connected by connecting to the FPC.

(Preparation of connection body B)
Connection body B was obtained by connecting over a width of 2 mm in the same manner as connection body A, except that 180 ° C. (through hole portion was 160 ° C.) and heated and pressurized at 3 MPa for 5 seconds.

(Example 2)
As an additive whose hue is changed by radical reaction, anthraquinone red (trade name SC-4014, manufactured by Nippon Pigment) was used in place of 1,1-diphenyl-2-picrylhydrazyl in Example 1. In the same manner as in Example 1, an anisotropic conductive film was produced and circuits were connected.

(Comparative Example 1)
An anisotropic conductive film was prepared and circuits were connected in the same manner as in Example 1 except that an additive that changes its hue by a radical reaction was not used.

[Measurement of connection resistance]
After the circuits in Examples 1 and 2 and Comparative Example 3 were connected, the resistance value between adjacent circuits of the FPC including the connection part was measured with a multimeter. The resistance value is measured with a multimeter at the initial stage (that is, after being connected to the circuit and before being held in a high-temperature and high-humidity tank described later) and after being held in a high-temperature and high-humidity tank at 85 ° C. and 85% RH for 500 hours. It was measured. The temperature at the time of measuring the resistance value was 23 ° C. As a result, in connection body A of Examples 1 and 2 and Comparative Example 1, the connection resistance value of the portion other than the through-hole portion is initially 0.1Ω, and the resistance value is 1Ω even after being held in high temperature and high humidity. The following good connection reliability was shown. On the other hand, in the through hole portion, the connection resistance value was initially 0.1Ω, but the resistance value increased to 5Ω or more after holding in high temperature and high humidity. While the heating temperature of the portion other than the through hole portion was 160 ° C., the heating temperature of the through hole portion was about 140 ° C., and it is considered that the connection reliability deteriorated due to insufficient reaction.
In addition, in connection body B of Examples 1 and 2 and Comparative Example 1, the connection resistance value of all parts was 0.1 Ω at the initial stage, and good connection with a resistance value of 1 Ω or less even after holding in high temperature and high humidity. Showed reliability.

(Measurement of adhesive strength)
After connecting the circuits, the adhesive strength was measured at 90 ° peeling and a peeling speed of 50 mm / min. In the connection bodies A and B of Examples 1 and 2 and Comparative Example 1, good adhesive strength of about 800 gf / cm was obtained.

(Hue change after curing)
In connection body A, the adhesive layer of the anisotropic conductive film of Example 1 had a slightly pink hue before connection, but the through-hole portion exhibited a slightly pink hue after connection, but the other portions. Changed its color to colorless. Further, the adhesive layer of the anisotropic conductive film of Example 2 had a slightly red hue before connection, but after connection, the through-hole portion exhibited a slightly red hue, but the other portions were colorless. The hue has changed. On the other hand, the anisotropic conductive adhesive of Comparative Example 1 was colorless before and after connection, and the hue did not change.
Moreover, in the connection body B, in Examples 1 and 2, the hue changed colorless in all parts, but the anisotropic conductive adhesive of Comparative Example 1 was colorless before and after connection and the hue did not change.

(Measurement of reaction rate)
The reaction rates of the through holes and the portions other than the through holes of the connectors of Examples 1 and 2 and Comparative Example 1 were measured by the peak change in the absorption wavelength region of acrylate by FT-IR. The parts other than the through hole part of the connection body A had a reaction rate of 70% or more in both Examples 1, 2 and Comparative Example 1, but the through hole part was 40 to 50%, and the part other than the through hole part It was lower than. Moreover, although the part other than the through hole part of the connection body B had a reaction rate of 70% or more in both Example 1 and Comparative Example 1, the through hole part was 40 to 50%, and the part other than the through hole part It was lower than.

(Reproducibility test)
In Examples 1 and 2, the heating / pressurization time is not measured, and the stop of heating / pressurization is visually determined based on the change in the hue of the adhesive layer of the anisotropic conductive film. Was made. When this operation was repeated 10 times, it was confirmed that all of the obtained connectors A and B had sufficient connection resistance and adhesive strength.

  On the other hand, in Comparative Example 1, the time for heating and pressurization was fixed to 5 seconds, and the production of the connectors A and B was repeated 10 times. As a result, 7 out of 10 obtained connection bodies A and 0 out of 10 connection bodies B had insufficient connection resistance or adhesive strength.

  As described above, according to the present invention, since the hue changes before and after the connection, it is possible to easily determine that the heating has been performed, and it is possible to provide an anisotropic conductive material having good connection characteristics.

It is a fragmentary sectional view showing one embodiment of a circuit member connection structure. (A)-(c) is a series of process drawings which connect a circuit member, respectively. It is a fragmentary sectional view showing one embodiment of a semiconductor device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Circuit member connection structure, 2 ... Semiconductor device, 5 ... Adhesive component, 7 ... Conductive particle, 10 ... Circuit connection member, 11 ... Insulating substance, 20 ... 1st circuit member, 21 ... 1st Circuit board, 22 ... first circuit electrode, 30 ... second circuit member, 31 ... second circuit board, 32 ... second circuit electrode, 40 ... film-like circuit connecting member, 50 ... semiconductor element, 60 ... Substrate, 61... Circuit pattern, 70... Sealing material, 80.

Claims (10)

A first circuit member having a first circuit electrode formed on the main surface of the first substrate; and a second circuit member having a second circuit electrode formed on the main surface of the second substrate. The first circuit electrode and the second circuit electrode are pressed and heated in a state of being opposed to each other, and the first circuit electrode and the second circuit electrode are electrically connected to each other. A conductive adhesive,
It is at least one selected from radically polymerizable substances, radical polymerization initiators, aromatic ketone compounds, 1,1-diphenyl-2-picrylhydrazyl, azobenzene, fulgides, diarylethenes and spirooxazine compounds. An additive that changes hue by a radical reaction,
A radical curable anisotropic conductive adhesive whose hue changes due to the radical reaction of the contained components. The anisotropic conductive adhesive according to claim 1 , wherein the aromatic ketone compound is anthraquinone or acetophenone. The anisotropic conductive adhesive according to claim 1 or 2 , wherein the additive whose hue is changed by the radical reaction is an anthraquinone compound or 1,1-diphenyl-2-picrylhydrazyl. Content of the additive hue change by the radical reaction, based on the total weight of the anisotropic conductive adhesive, according to claim 1, from 0.01 to 10 wt% Anisotropic conductive adhesive. Content of the additive hue change by the radical reaction, based on the total weight of the anisotropic conductive adhesive, according to claim 1, from 0.05 to 5 wt% Anisotropic conductive adhesive. The content of the additive whose hue is changed by the radical reaction is 0.1 to 1% by weight, based on the total weight of the anisotropic conductive adhesive, according to any one of claims 1 to 5 . Anisotropic conductive adhesive. The anisotropic conductive adhesive according to any one of claims 1 to 6, further containing conductive particles. Anisotropic conductive film obtained by forming an anisotropic conductive adhesive according to the film-like to any one of claims 1-7. A first circuit member having a first circuit electrode formed on the main surface of the first substrate; and a second circuit member having a second circuit electrode formed on the main surface of the second substrate. The first circuit electrode and the second circuit electrode are connected via the anisotropic conductive adhesive according to any one of claims 1 to 7 or the anisotropic conductive film according to claim 8. A method for manufacturing a circuit connection structure comprising a step of pressurizing and heating in a state of being opposed to each other and electrically connecting the first circuit electrode and the second circuit electrode. A circuit connecting member;
A first circuit member and a second circuit member facing each other via the circuit connection member,
The first circuit member has a first circuit electrode formed on the main surface of the first substrate,
The second circuit member has a second circuit electrode formed on the main surface of the second substrate,
The first circuit electrode and the second circuit electrode are electrically connected; and
A circuit connection structure, wherein the circuit connection member is formed using the anisotropic conductive adhesive according to any one of claims 1 to 7 or the anisotropic conductive film according to claim 8. body.

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