JP5916423B2 - B-staged product of anisotropic conductive material, method for manufacturing B-staged product of anisotropic conductive material, connection structure, and method for manufacturing connection structure - Google Patents

Description

  The present invention is an anisotropic conductive material including a plurality of conductive particles, and can be used for electrical connection between electrodes of various connection target members such as a flexible printed circuit board, a glass substrate, and a semiconductor chip. The present invention relates to an anisotropic conductive material, a connection structure using the anisotropic conductive material, and a method of manufacturing the connection structure.

  Pasty or film-like anisotropic conductive materials are widely known. In the anisotropic conductive material, a plurality of conductive particles are dispersed in a binder resin.

  The anisotropic conductive material includes, for example, a connection between a flexible printed circuit board and a glass substrate (FOG (Film on Glass)), a connection between a semiconductor chip and a flexible printed circuit board (COF (Chip on Film)), and a semiconductor chip. It is used for connection with a glass substrate (COG (Chip on Glass)) and the like.

  As an example of the anisotropic conductive material, Patent Document 1 below includes an epoxy resin, rubber-like polymer particles, a thermally active latent epoxy curing agent, high softening point polymer particles, and conductive particles. An anisotropic conductive material is disclosed.

  Patent Document 2 below describes anisotropy satisfying the following formulas (A) and (B) when the viscosity at 25 ° C. and 2.5 pm is η1, and the viscosity at 25 ° C. and 20 rpm is η2. A conductive adhesive is disclosed.

50 Pa · s ≦ η2 ≦ 200 Pa · s Formula (A)
1.5 ≦ η1 / η2 ≦ 4.3 Formula (B)

JP 2000-345010 A JP 2003-064330 A

  For example, when the electrode of the semiconductor chip and the electrode of the glass substrate are electrically connected by the anisotropic conductive material, an anisotropic conductive material containing conductive particles is disposed on the glass substrate. Next, the semiconductor chips are stacked, and heated and pressurized. As a result, the anisotropic conductive material is cured, and the electrodes are electrically connected via the conductive particles to obtain a connection structure.

  In the conventional anisotropic conductive materials described in Patent Documents 1 and 2, the anisotropic conductive material applied on the glass substrate at the time of electrical connection between the electrodes and the anisotropic conductive material In some cases, the conductive particles contained in the fluid flow largely before curing. For this reason, the hardened | cured material layer and electroconductive particle formed with the anisotropic electrically-conductive material may be unable to be arrange | positioned in a specific area | region. Furthermore, the conductive particles may not be disposed between the upper and lower electrodes to be connected, or adjacent electrodes that should not be connected may be electrically connected via a plurality of conductive particles. For this reason, the conduction | electrical_connection reliability of the obtained connection structure may be low.

  An object of the present invention is an anisotropic conductive material containing conductive particles, which can increase conduction reliability when used for electrical connection between electrodes, and the It is to provide a connection structure using an anisotropic conductive material and a method for manufacturing the connection structure.

  According to a wide aspect of the present invention, there is provided an anisotropic conductive material containing a curable compound, a thermal radical initiator, a photo radical initiator, and conductive particles.

  In a specific aspect of the anisotropic conductive material according to the present invention, the curable compound includes a curable compound having a (meth) acryloyl group.

  In another specific aspect of the anisotropic conductive material according to the present invention, a decomposition temperature for obtaining a 10-hour half-life of the thermal radical initiator is 30 ° C. or higher and 80 ° C. or lower.

  The viscosity of the anisotropic conductive material according to the present invention at 25 ° C. and 2.5 rpm is preferably 20 Pa · s or more and 200 Pa · s or less.

  In another specific aspect of the anisotropic conductive material according to the present invention, the viscosity after being cured by light irradiation to be B-staged is 2000 Pa · s or more and 15000 Pa · s or less.

  In the anisotropic conductive material according to the present invention, when the viscosity at 25 ° C. and 2.5 rpm is η1, and the viscosity at 25 ° C. and 5 rpm is η2, the η2 is 20 Pa · s or more and 200 Pa · s. The ratio (η1 / η2) of η1 to η2 is 0.9 or more and 1.1 or less.

  The anisotropic conductive material according to the present invention may be a film-like anisotropic conductive film or a paste-like anisotropic conductive paste. The anisotropic conductive material according to the present invention is preferably a paste-like anisotropic conductive paste.

  The connection structure according to the present invention includes a first connection target member, a second connection target member, and a connection part that electrically connects the first and second connection target members. The connecting portion is formed by curing an anisotropic conductive material configured according to the present invention.

  The method for manufacturing a connection structure according to the present invention includes a step of disposing an anisotropic conductive material configured according to the present invention on the upper surface of the first connection target member to form an anisotropic conductive material layer; Curing the anisotropic conductive material layer by irradiating with light, and making the anisotropic conductive material layer into a B-stage so that the viscosity is 2000 Pa · s to 15000 Pa · s; And a step of further laminating a second connection target member on the upper surface of the B-staged anisotropic conductive material layer.

  Since the anisotropic conductive material according to the present invention contains a curable compound, a thermal radical initiator, a photo radical initiator, and conductive particles, the anisotropic conductive material is cured by light irradiation and heating. Can do. For example, after the anisotropic conductive material is semi-cured by light irradiation or heating, the anisotropic conductive material can be cured by thermosetting or photocuring. For this reason, the flow of the anisotropic conductive material and the conductive particles contained in the anisotropic conductive material can be suppressed by irradiating the anisotropic conductive material with light or applying heat to the anisotropic conductive material at an appropriate time. Therefore, the hardened | cured material layer and electroconductive particle formed with the anisotropic electrically-conductive material can be arrange | positioned in a specific area | region. For this reason, when the anisotropic conductive material which concerns on this invention is used for the electrical connection between electrodes, conduction | electrical_connection reliability can be improved.

FIG. 1 is a front sectional view schematically showing a connection structure using an anisotropic conductive material according to an embodiment of the present invention. FIGS. 2A to 2C are partial cutaway front sectional views for explaining each step of obtaining a connection structure using the anisotropic conductive material according to one embodiment of the present invention.

  Hereinafter, the present invention will be described in detail.

  The anisotropic conductive material according to the present invention contains a curable compound, a thermal radical curing agent, a photo radical initiator, and conductive particles.

  First, the detail of each component contained in the anisotropic conductive material which concerns on this invention is demonstrated.

(Curable compound)
The curable compound is not particularly limited. As the curable compound, a conventionally known curable compound can be used. As for the said sclerosing | hardenable compound, only 1 type may be used and 2 or more types may be used together.

  As said curable compound, a photocurable compound and a thermosetting compound are mentioned. The photocurable compound can be cured by light irradiation. The photocurable compound has photocurability. The thermosetting compound can be cured by heating. The thermosetting compound has thermosetting properties. The photocurable compound may have photocurability and thermosetting properties, and may be light and thermosetting compounds. The curable compound includes at least the light and thermosetting compounds, or includes a photocurable compound and a thermosetting compound.

  The curable compound is not particularly limited. Examples of the curable compound include epoxy compounds, episulfide compounds, (meth) acrylic compounds, phenolic compounds, amino compounds, unsaturated polyester compounds, polyurethane compounds, silicone compounds, and polyimide compounds. The (meth) acryl means acryl or methacryl.

  From the viewpoint of easily controlling the viscosity η2 and the ratio (η1 / η2) within the above range and further improving the conduction reliability in the connection structure, the curable compound may contain a crystalline resin. preferable.

  The crystalline resin is not particularly limited as long as it has crystallinity. Examples of the crystalline resin include a resin having a photocurable functional group in the naphthalene skeleton structure, a resin having a thermosetting functional group in the naphthalene skeleton structure, and a resin having a photocurable functional group in the resorcin skeleton structure. In addition, a resin having a thermosetting functional group in the resorcin skeleton structure may be used.

  From the viewpoint of easily controlling the viscosity η2 and the ratio (η1 / η2) within the above range and further enhancing the conduction reliability in the connection structure, the crystalline resin is contained in 100% by weight of the curable compound. The content of is preferably 80% by weight or more, more preferably 90% by weight or more and 100% by weight or less. The total amount of the curable compound may be the crystalline resin.

[Thermosetting compound]
From the viewpoint of easily controlling the curing of the anisotropic conductive material and further improving the conduction reliability in the connection structure, the anisotropic conductive material according to the present invention is thermally cured so as to be cured by heating. It is preferable to contain a functional compound.

  It does not specifically limit as said thermosetting compound, (meth) acrylic resin etc. are mentioned. The thermosetting compound is preferably a thermosetting compound having a (meth) acryloyl group.

  As the thermosetting compound having the (meth) acryloyl group, an ester compound obtained by reacting a compound having (meth) acrylic acid and a hydroxyl group, an epoxy obtained by reacting (meth) acrylic acid and an epoxy compound. (Meth) acrylate or urethane (meth) acrylate obtained by reacting a (meth) acrylic acid derivative having a hydroxyl group with isocyanate is preferably used. The “(meth) acryloyl group” refers to an acryloyl group and a methacryloyl group. The “(meth) acryl” refers to acryl and methacryl. The “(meth) acrylate” refers to acrylate and methacrylate.

  The ester compound obtained by making the said (meth) acrylic acid and the compound which has a hydroxyl group react is not specifically limited. As the ester compound, any of a monofunctional ester compound, a bifunctional ester compound, and a trifunctional or higher functional ester compound can be used.

  The thermosetting compound may be a crosslinkable compound or a non-crosslinkable compound. From the viewpoint of further improving the conduction reliability in the connection structure of the anisotropic conductive material, a crosslinkable compound is preferable.

  Specific examples of the crosslinkable compound include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, (poly ) Ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, glycerine methacrylate acrylate, pentaerythritol tri (meth) acrylate, tri Examples include methylolpropane trimethacrylate, allyl (meth) acrylate, vinyl (meth) acrylate, divinylbenzene, polyester (meth) acrylate, and urethane (meth) acrylate.

  Specific examples of the non-crosslinkable compound include ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) ) Acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, decyl (Meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, and the like.

[Photocurable compound]
The anisotropic conductive material according to the present invention preferably contains a photocurable compound so as to be cured by light irradiation. By photoirradiation, the photocurable compound can be semi-cured to reduce the fluidity of the curable compound.

  It does not specifically limit as said photocurable compound, A (meth) acrylic resin etc. are mentioned. The photocurable compound is preferably a photocurable compound having a (meth) acryloyl group.

  As a photocurable compound having the above (meth) acryloyl group, an ester compound obtained by reacting a compound having (meth) acrylic acid and a hydroxyl group, an epoxy obtained by reacting (meth) acrylic acid and an epoxy compound. (Meth) acrylate or urethane (meth) acrylate obtained by reacting a (meth) acrylic acid derivative having a hydroxyl group with isocyanate is preferably used. The “(meth) acryloyl group” refers to an acryloyl group and a methacryloyl group. The “(meth) acryl” refers to acryl and methacryl. The “(meth) acrylate” refers to acrylate and methacrylate.

  The ester compound obtained by making the said (meth) acrylic acid and the compound which has a hydroxyl group react is not specifically limited. As the ester compound, any of a monofunctional ester compound, a bifunctional ester compound, and a trifunctional or higher functional ester compound can be used.

  Further, the photocurable compound may be a crosslinkable compound or a non-crosslinkable compound. Specific examples of the crosslinkable compound and the non-crosslinkable compound which are the photocurable compounds include the compounds mentioned as the crosslinkable compound and the noncrosslinkable compound which are the thermosetting compounds.

  When a photocurable compound and a thermosetting compound are used in combination, the blending ratio of the photocurable compound and the thermosetting compound is appropriately adjusted according to the type of the photocurable compound and the thermosetting compound. The When the photocurable compound and the thermosetting compound are used in combination, the anisotropic conductive material according to the present invention has a weight ratio of the photocurable compound and the thermosetting compound of 1:99 to 90:10. Preferably, it is included at 5:95 to 60:40, more preferably 10:90 to 40:60.

[Thermal radical initiator]
The thermal radical initiator is not particularly limited. As the thermal radical initiator, a conventionally known thermal radical initiator can be used. As for the said thermal radical initiator, only 1 type may be used and 2 or more types may be used together. Here, the “thermal radical initiator” means a compound that generates radical species by heating.

  The thermal radical initiator is not particularly limited, and examples thereof include azo compounds and peroxides. Examples of the peroxide include diacyl peroxide compounds, peroxyester compounds, hydroperoxide compounds, peroxydicarbonate compounds, peroxyketal compounds, dialkyl peroxide compounds, and ketone peroxide compounds.

  Examples of the azo compound include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), and 2,2′-azobis (2,4-dimethylvaleronitrile). 1,1′-azobis-1-cyclohexanecarbonitrile, dimethyl-2,2′-azobisisobutyrate, dimethyl-2,2′-azobis (2-methylpropionate), dimethyl-1,1 ′ -Azobis (1-cyclohexanecarboxylate), 4,4'-azobis (4-cyanovaleric acid), 2,2'-azobis (2-amidinopropane) dihydrochloride, 2-tert-butylazo-2-cyanopropane 2,2′-azobis (2-methylpropionamide) dihydrate, 2,2′-azobis (2,4,4-trimethylpentane), and the like.

  Examples of the diacyl peroxide compound include benzoyl peroxide, diisobutyryl peroxide, di (3,5,5-trimethylhexanoyl) peroxide, dilauroyl peroxide, and disuccinic acid peroxide. Examples of the peroxyester compound include cumylperoxyneodecanoate, 1,1,3,3-tetramethylbutylperoxyneodecanoate, tert-hexylperoxyneodecanoate, and tert-butylperoxyneo. Decanoate, tert-butylperoxyneoheptanoate, tert-hexylperoxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5-dimethyl-2 , 5-di (2-ethylhexanoylperoxy) hexane, tert-hexylperoxy-2-ethylhexanoate, tert-butylperoxypivalate, tert-butylperoxy-2-ethylhexanoate, tert -Butyl peroxyisobutyrate, tert-butyl per Kishiraureto, tert- butylperoxy isophthalate, tert- butylperoxy acetate, tert- butylperoxy octoate and tert- butyl peroxybenzoate, and the like. Examples of the hydroperoxide compound include cumene hydroperoxide and p-menthane hydroperoxide. Examples of the peroxydicarbonate compound include di-sec-butyl peroxydicarbonate, di (4-t-butylcyclohexyl) peroxydicarbonate, di-n-propyl peroxydicarbonate, diisopropyl peroxycarbonate, and di- (2-ethylhexyl) peroxycarbonate and the like. Other examples of the peroxide include methyl ethyl ketone peroxide, potassium persulfate, and 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane.

  The decomposition temperature for obtaining the 10-hour half-life of the thermal radical initiator is preferably 30 ° C. or higher, more preferably 40 ° C. or higher, preferably 80 ° C. or lower, more preferably 70 ° C. or lower. When the decomposition temperature for obtaining the 10-hour half-life of the thermal radical initiator is less than 30 ° C., the storage stability of the anisotropic conductive material tends to be lowered. It tends to be difficult to sufficiently heat cure the conductive material.

  The content of the thermal radical initiator is not particularly limited. The content of the thermal radical initiator is preferably 0.01 parts by weight or more, more preferably 0.05 parts by weight or more, preferably 10 parts by weight or less, based on 100 parts by weight of the total amount of the curable compound. The amount is preferably 5 parts by weight or less. When the content of the thermal radical curing agent is not less than the above lower limit and not more than the above upper limit, the anisotropic conductive material can be sufficiently thermoset.

[Photo radical initiator]
The photo radical initiator is not particularly limited. A conventionally known photoradical initiator can be used as the photoradical initiator. As for the said photoradical initiator, only 1 type may be used and 2 or more types may be used together.

  The photo radical initiator is not particularly limited, and examples thereof include acetophenone photo radical initiator, benzophenone photo radical initiator, thioxanthone, ketal photo radical initiator, halogenated ketone, acyl phosphinoxide, and acyl phosphonate. .

  Specific examples of the acetophenone photoradical initiator include 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, methoxy Examples include acetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, and 2-hydroxy-2-cyclohexylacetophenone. Specific examples of the ketal photoradical initiator include benzyldimethyl ketal.

  The content of the photo radical initiator is not particularly limited. The content of the photo radical initiator is preferably 0.1 parts by weight or more, more preferably 0.2 parts by weight or more, preferably 2 parts by weight or less, based on 100 parts by weight of the total amount of the curable compound. The amount is preferably 1 part by weight or less. When the content of the photo radical initiator is not less than the above lower limit and not more than the above upper limit, the anisotropic conductive material can be appropriately photocured. By irradiating the anisotropic conductive material with light to form a B stage, the flow of the anisotropic conductive material can be suppressed.

(Conductive particles)
The conductive particles contained in the anisotropic conductive material electrically connect the electrodes of the first and second connection target members. The conductive particles are not particularly limited as long as they are conductive particles. The surface of the conductive layer of the conductive particles may be covered with an insulating layer. In this case, the insulating layer between the conductive layer and the electrode is excluded when the connection target member is connected. Examples of the conductive particles include conductive particles whose surfaces are coated with a metal layer, such as organic particles, inorganic particles, organic-inorganic hybrid particles, or metal particles, or metal particles that are substantially composed of only metal. It is done. The metal layer is not particularly limited. Examples of the metal layer include a gold layer, a silver layer, a copper layer, a nickel layer, a palladium layer, or a metal layer containing tin.

  From the viewpoint of increasing the contact area between the electrode and the conductive particle and further improving the conduction reliability between the electrodes, the conductive particle includes a resin particle and a conductive layer disposed on the surface of the resin particle. It is preferable to have. From the viewpoint of further improving the conduction reliability between the electrodes, the conductive particles are preferably conductive particles having at least an outer conductive surface as a low melting point metal layer. More preferably, the conductive particles include resin particles and a conductive layer disposed on the surface of the resin particles, and at least the outer surface of the conductive layer is a low melting point metal layer.

  The low melting point metal layer is a layer containing a low melting point metal. The low melting point metal is a metal having a melting point of 450 ° C. or lower. The melting point of the low melting point metal is preferably 300 ° C. or lower, more preferably 160 ° C. or lower. The low melting point metal layer preferably contains tin. In 100% by weight of the metal contained in the low melting point metal layer, the content of tin is preferably 30% by weight or more, more preferably 40% by weight or more, still more preferably 70% by weight or more, and particularly preferably 90% by weight or more. . When the content of tin in the low melting point metal layer is not less than the above lower limit, the connection reliability between the low melting point metal layer and the electrode is further enhanced. The tin content is determined using a high frequency inductively coupled plasma optical emission spectrometer (“ICP-AES” manufactured by Horiba, Ltd.) or a fluorescent X-ray analyzer (“EDX-800HS” manufactured by Shimadzu). It can be measured.

  When the outer surface of the conductive layer is a low melting point metal layer, the low melting point metal layer is melted and joined to the electrodes, and the low melting point metal layer conducts between the electrodes. For example, since the low-melting point metal layer and the electrode are not in point contact but in surface contact, the connection resistance is lowered. In addition, the use of conductive particles having at least the outer surface of a low-melting-point metal layer increases the bonding strength between the low-melting-point metal layer and the electrode. , The conduction reliability is effectively increased.

  The low melting point metal which comprises the said low melting metal layer is not specifically limited. The low melting point metal is preferably tin or an alloy containing tin. Examples of the alloy include a tin-silver alloy, a tin-copper alloy, a tin-silver-copper alloy, a tin-bismuth alloy, a tin-zinc alloy, and a tin-indium alloy. Especially, since it is excellent in the wettability with respect to an electrode, it is preferable that the said low melting metal is a tin, a tin-silver alloy, a tin-silver-copper alloy, a tin-bismuth alloy, and a tin-indium alloy. More preferred are a tin-bismuth alloy and a tin-indium alloy.

  The low melting point metal layer is preferably a solder layer. Although the material which comprises the said solder layer is not specifically limited, Based on JISZ3001: solvent term, it is preferable that it is a meltable material whose liquidus is 450 degrees C or less. As a composition of the said solder layer, the metal composition containing zinc, gold | metal | money, lead, copper, tin, bismuth, indium etc. is mentioned, for example. Among them, a tin-indium system (117 ° C. eutectic) or a tin-bismuth system (139 ° C. eutectic) which is low-melting and lead-free is preferable. That is, the solder layer preferably does not contain lead, and is preferably a solder layer containing tin and indium or a solder layer containing tin and bismuth.

  In order to further enhance the bonding strength between the low melting point metal layer and the electrode, the low melting point metal layer is made of nickel, copper, antimony, aluminum, zinc, iron, gold, titanium, phosphorus, germanium, tellurium, cobalt, bismuth. Further, it may contain a metal such as manganese, chromium, molybdenum and palladium. From the viewpoint of further increasing the bonding strength between the low melting point metal and the electrode, the low melting point metal preferably contains nickel, copper, antimony, aluminum, or zinc. From the viewpoint of further increasing the bonding strength between the low melting point metal layer and the electrode, the content of these metals for increasing the bonding strength is 100 wt% of the low melting point metal layer, preferably 0.0001 wt% or more, Preferably it is 1 weight% or less.

  The conductive particles include resin particles and a conductive layer disposed on the surface of the resin particles, and the outer surface of the conductive layer is a low melting point metal layer (such as a solder layer). In addition to the low melting point metal layer, a second conductive layer is preferably provided between the low melting point metal layer and the low melting point metal layer. In this case, the low melting point metal layer is a part of the entire conductive layer, and the second conductive layer is a part of the entire conductive layer.

  The second conductive layer different from the low melting point metal layer preferably contains a metal. The metal constituting the second conductive layer is not particularly limited. Examples of the metal include gold, silver, copper, platinum, palladium, zinc, lead, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, germanium and cadmium, and alloys thereof. Further, tin-doped indium oxide (ITO) may be used as the metal. As for the said metal, only 1 type may be used and 2 or more types may be used together.

  The second conductive layer is preferably a nickel layer, a palladium layer, a copper layer, or a gold layer, more preferably a nickel layer or a gold layer, and even more preferably a copper layer. The conductive particles preferably have a nickel layer, a palladium layer, a copper layer, or a gold layer, more preferably have a nickel layer or a gold layer, and still more preferably have a copper layer. By using the conductive particles having these preferable conductive layers for the connection between the electrodes, the connection resistance between the electrodes is further reduced. In addition, a low melting point metal layer can be more easily formed on the surface of these preferable conductive layers. The second conductive layer may be a low melting point metal layer such as a solder layer. The conductive particles may have a plurality of low melting point metal layers.

  The thickness of the low melting point metal layer is preferably 0.1 μm or more, more preferably 0.5 μm or more, still more preferably 1 μm or more, preferably 50 μm or less, more preferably 10 μm or less, still more preferably 5 μm or less, particularly preferably. 3 μm or less. When the thickness of the low melting point metal layer is not less than the above lower limit, the conductivity is sufficiently high. When the thickness of the low melting point metal layer is not more than the above upper limit, the difference in thermal expansion coefficient between the resin particles and the low melting point metal layer becomes small, and the low melting point metal layer is hardly peeled off.

  When the conductive layer is a conductive layer other than the low melting point metal layer, or when the conductive layer has a multilayer structure, the total thickness of the conductive layer is preferably 0.1 μm or more, more preferably 0.5 μm or more, Preferably it is 1 micrometer or more, Preferably it is 50 micrometers or less, More preferably, it is 10 micrometers or less, More preferably, it is 5 micrometers or less, Most preferably, it is 3 micrometers or less.

  The particle diameter of the conductive particles is preferably 100 μm or less, more preferably less than 20 μm, still more preferably 15 μm or less, and particularly preferably 10 μm or less. The particle diameter of the conductive particles is preferably 0.5 μm or more, more preferably 1 μm or more.

  Since the size is suitable for the conductive particles in the anisotropic conductive material and the distance between the electrodes can be further reduced, the average particle diameter of the conductive particles is in the range of 1 μm to 100 μm. Is particularly preferred.

  The resin particles can be properly used depending on the electrode size or land diameter of the substrate to be mounted.

  From the viewpoint of more reliably connecting the upper and lower electrodes and further suppressing the short circuit between the electrodes adjacent in the lateral direction, the ratio of the average particle diameter C of the conductive particles to the average particle diameter A of the resin particles ( C / A) is more than 1.0, preferably 3.0 or less. In addition, when the second conductive layer is present between the resin particles and the solder layer, the ratio of the resin particles to the average particle size B with respect to the average particle size B of the conductive particle portion excluding the solder layer (B / A) is greater than 1.0, preferably 2.0 or less. Further, when there is the second conductive layer between the resin particles and the solder layer, the average particle diameter B of the conductive particle portion excluding the solder layer having the average particle diameter C of the conductive particles including the solder layer. The ratio (C / B) to is more than 1.0, preferably 2.0 or less. When the ratio (B / A) is within the above range or the ratio (C / B) is within the above range, electrodes that are more reliably connected between the upper and lower electrodes and that are adjacent in the lateral direction The short circuit between them can be further suppressed.

Anisotropic conductive materials for FOB and FOF applications:
The anisotropic conductive material is used for connection between a flexible printed circuit board and a glass epoxy board (FOB (Film on Board)), or between a flexible printed circuit board and a flexible printed circuit board (FOF (Film on Film)). Preferably used.

  In FOB and FOF applications, L & S, which is the size of a portion (line) with an electrode and a portion (space) without an electrode, is generally 100 to 500 μm. The average particle diameter of the resin particles used for FOB and FOF applications is preferably 10 to 100 μm. When the average particle diameter of the resin particles is 10 μm or more, the thickness of the anisotropic conductive material disposed between the electrodes and the connection portion is sufficiently increased, and the adhesive force is further increased. When the average particle diameter of the resin particles is 100 μm or less, a short circuit is more unlikely to occur between adjacent electrodes.

Anisotropic conductive materials for flip chip applications:
The anisotropic conductive material is suitably used for flip chip applications.

  For flip chip applications, the land diameter is generally 15-80 μm. The average particle size of the resin particles used for flip chip applications is preferably 1 to 15 μm. When the average particle diameter of the resin particles is 1 μm or more, the thickness of the solder layer disposed on the surface of the resin particles can be sufficiently increased, and the electrodes can be more reliably electrically connected. it can. When the average particle diameter of the resin particles is 10 μm or less, a short circuit is more unlikely to occur between adjacent electrodes.

Anisotropic conductive material for COF:
The anisotropic conductive material is preferably used for connection between a semiconductor chip and a flexible printed board (COF (Chip on Film)).

  In a COF application, L & S, which is a dimension between a portion (line) with an electrode and a portion (space) without an electrode (space), is generally 10 to 50 μm. The average particle diameter of the resin particles used for COF applications is preferably 1 to 10 μm. When the average particle diameter of the resin particles is 1 μm or more, the thickness of the solder layer disposed on the surface of the resin particles can be sufficiently increased, and the electrodes can be more reliably electrically connected. it can. When the average particle diameter of the resin particles is 10 μm or less, a short circuit is more unlikely to occur between adjacent electrodes.

  The “average particle size” of the conductive particles indicates a number average particle size. The average particle diameter of the conductive particles can be obtained by observing 50 arbitrary conductive particles with an electron microscope or an optical microscope and calculating an average value.

  The surface of the conductive particles may be insulated with an insulating material, insulating particles, flux, or the like. It is preferable that the insulating material, the insulating particles, the flux, and the like are removed from the connection portion by being softened and flowed by heat at the time of connection. Thereby, the short circuit between electrodes can be suppressed.

  The content of the conductive particles is not particularly limited. The content of the conductive particles in 100% by weight of the anisotropic conductive material is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, preferably 40% by weight or less, more preferably 20% by weight. % Or less, more preferably 10% by weight or less. A conductive particle can be easily arrange | positioned between the upper and lower electrodes which should be connected as content of the said electroconductive particle is more than the said minimum and below the said upper limit. Furthermore, it becomes difficult to electrically connect adjacent electrodes that should not be connected via a plurality of conductive particles. That is, a short circuit between adjacent electrodes can be further prevented.

(Other ingredients)
The anisotropic conductive material may contain a solvent. By using the solvent, the viscosity of the anisotropic conductive material can be easily adjusted. Furthermore, for example, when the curable compound is solid, the dispersibility of the curable compound can be increased by adding a solvent to the solid curable compound and dissolving it. Examples of the solvent include ethyl acetate, methyl cellosolve, toluene, acetone, methyl ethyl ketone, cyclohexane, n-hexane, tetrahydrofuran, and diethyl ether.

  Since the adhesive force of the cured product of the anisotropic conductive material can be increased, the anisotropic conductive material according to the present invention preferably contains an adhesive force adjusting agent. From the viewpoint of further increasing the adhesive strength, the adhesive strength modifier is preferably a silane coupling agent.

  The anisotropic conductive material preferably contains a filler. By using the filler, latent heat expansion of the cured product of the anisotropic conductive material can be suppressed.

  In order to control the η2 and the ratio (η1 / η2) within a suitable range, the filler is preferably surface-treated, and is preferably a hydrophilic filler.

  The filler is not particularly limited. Examples of the filler include silica, aluminum nitride, and alumina. As for the said filler, only 1 type may be used and 2 or more types may be used together.

  The hydrophilic filler refers to a filler whose surface is covered with a hydrophilic group. Examples of the hydrophilic group include polar groups such as hydroxyl group, amino group, amide group, carboxylate group and carboxyl group, and ionic groups such as carboxylate ion group, sulfonate ion group and ammonium ion group. Examples of the hydrophilic filler include a hydrophilic filler obtained by surface-treating the conventional filler with a hydrophilic surface treatment agent.

Examples of the hydrophilic surface treatment agent include silane coupling agents, titanate coupling agents, aluminum coupling agents, zircoaluminate coupling agents, Al ₂ O ₃ , TiO ₂ , ZrO ₂ , silicone, and stearin. An aluminum acid etc. are mentioned. Among these, a silane coupling agent is preferably used as the hydrophilic surface treatment agent.

  The content of the filler is not particularly limited. The content of the filler is preferably 5 parts by weight or more, more preferably 15 parts by weight or more, preferably 300 parts by weight or less, more preferably 200 parts by weight or less with respect to 100 parts by weight of the total amount of the curable compound. . When the content of the filler is not less than the above lower limit and not more than the above upper limit, latent heat expansion of the cured product of the anisotropic conductive material can be sufficiently suppressed, and the filler can be sufficiently dispersed in the anisotropic conductive material. it can.

(Other details of anisotropic conductive material)
It does not specifically limit as a manufacturing method of the anisotropic electrically-conductive material which concerns on this invention, The said sclerosing | hardenable compound, the said thermal radical hardening | curing agent, the said photoradical initiator, and the said electroconductive particle are added as needed. The manufacturing method which mix | blends with another component and fully mixes using a planetary stirrer etc. is mentioned.

  The viscosity of the anisotropic conductive material according to the present invention at 25 ° C. and 2.5 rpm is preferably 20 Pa · s or more, and preferably 200 Pa · s or less. That is, the viscosity at 25 ° C. and 2.5 rpm of the anisotropic conductive material before placement (application) is preferably 20 Pa · s or more, and preferably 200 Pa · s or less. In this case, for example, the flow of the anisotropic conductive material before curing can be further suppressed after applying the anisotropic conductive material on the application target member (first connection target member) such as a substrate. Furthermore, the resin component between the electrode and the conductive particles can be easily removed, and the contact area between the electrode and the conductive particles can be increased. Furthermore, when the surface of the application target member (first connection target member) is uneven, the surface of the unevenness can be sufficiently filled with an anisotropic conductive material, and voids are less likely to occur after curing. Further, it becomes difficult for the conductive particles to settle in the anisotropic conductive material, and the dispersibility of the conductive particles can be improved.

  With respect to the anisotropic conductive material according to the present invention, the viscosity after being cured by light irradiation to be B-staged (hereinafter sometimes abbreviated as η3 ′) is preferably 2000 Pa · s or more, preferably 2250 Pa · s or more, preferably 15000 Pa · s or less, more preferably 12000 Pa · s or less, still more preferably 10000 Pa · s or less, particularly preferably 3500 Pa · s or less, and most preferably 3250 Pa · s. The measurement temperature of the viscosity η3 ′ is preferably 20 ° C. or higher, preferably 30 ° C. or lower. The measurement temperature of the viscosity η3 ′ is particularly preferably 25 ° C.

  In the anisotropic conductive material according to the present invention, when the viscosity at 25 ° C. and 2.5 rpm is η1, and the viscosity at 25 ° C. and 5 rpm is η2, the η2 is 20 Pa · s or more and 200 Pa · s. The ratio (η1 / η2) of η1 to η2 is preferably 0.9 or more and 1.1 or less. That is, the anisotropic conductive material according to the present invention preferably satisfies both the following formulas (X) and (Y).

20 Pa · s ≦ η2 ≦ 200 Pa · s Formula (X)
0.9 ≦ η1 / η2 ≦ 1.1 Formula (Y)

  When a conventional anisotropic conductive material as described in JP-A-2003-064330 is applied to a member to be applied with a dispenser or the like, it may not be applied stably. In an anisotropic conductive material having a viscosity characteristic as described in JP-A-2003-064330, the viscosity is greatly reduced immediately after the start of application, and the anisotropic conductive material may be partially applied in large quantities. is there. For this reason, the coating width is not constant, and as a result, the width or thickness of the cured product layer formed of the anisotropic conductive material tends to vary. On the other hand, in the anisotropic conductive material according to the present invention, when the η2 and the ratio (η1 / η2) are within the specific range, the anisotropic conductive material is dispensed by a dispenser or the like. When applying to the application target member, it can be applied more stably and uniformly. Furthermore, it is possible to prevent the anisotropic conductive material from being partially applied in a large amount without greatly reducing the viscosity immediately after the start of the application. For this reason, the coating width can be made constant, and as a result, variations in the width or thickness of the cured product layer formed of the anisotropic conductive material are less likely to occur.

  From the viewpoint of more uniformly applying the anisotropic conductive material, η2 is preferably 50 Pa · s or more, more preferably 100 Pa · s or more, preferably 180 Pa · s or less, more preferably 150 Pa · s or less. .

  The η2 and the ratio (η1 / η2) can be adjusted by using a crystalline resin as the curable compound, or by using a filler that has been surface-treated to improve hydrophilicity. From the viewpoint of easily controlling the η2 and the ratio (η1 / η2) within the above range, the curable compound preferably contains a crystalline resin.

  As a method for curing the anisotropic conductive material according to the present invention, after the anisotropic conductive material is irradiated with light, the anisotropic conductive material is heated, and after the anisotropic conductive material is heated, the anisotropic conductive material is heated. A method of irradiating the anisotropic conductive material with light can be given. In addition, when the photocuring speed and the thermosetting speed are different, light irradiation and heating may be performed simultaneously. Especially, the method of heating an anisotropic conductive material after irradiating light to an anisotropic conductive material is preferable. The anisotropic conductive material can be cured in a short time by the combined use of photocuring and heat curing.

(Connection structure and method of manufacturing connection structure)
A connection structure can be obtained by connecting the connection target members using the anisotropic conductive material according to the present invention.

  The connection structure includes a first connection target member, a second connection target member, and a connection portion that electrically connects the first and second connection target members. The part is formed by curing the anisotropic conductive material. The connection portion is a cured product layer obtained by curing the anisotropic conductive material.

  Next, a connection structure using an anisotropic conductive material according to an embodiment of the present invention and a method for manufacturing the connection structure will be described in more detail with reference to the drawings.

  In FIG. 1, an example of the connection structure using the anisotropic conductive material which concerns on one Embodiment of this invention is typically shown with a partial notch front sectional drawing.

  A connection structure 1 shown in FIG. 1 includes a first connection target member 2, a second connection target member 4, and a connection portion 3 connecting the first and second connection target members. The connection portion 3 is formed by curing an anisotropic conductive material including a curable compound, a thermal radical curing agent, a photo radical initiator, and the conductive particles 5. The anisotropic conductive material includes a plurality of conductive particles 5.

  The first connection target member 2 has a plurality of electrodes 2b on the upper surface 2a (front surface). The second connection target member 4 has a plurality of electrodes 4b on the lower surface 4a (front surface). The electrode 2b and the electrode 4b are electrically connected by one or a plurality of conductive particles 5.

  In the connection structure 1, a glass substrate is used as the first connection target member 2, and a semiconductor chip is used as the second connection target member 4. The first and second connection target members are not particularly limited. Specific examples of the first and second connection target members include electronic components such as semiconductor chips, capacitors, and diodes, and circuit boards such as printed boards, flexible printed boards, and glass boards. The anisotropic conductive material is preferably an anisotropic conductive material used for connecting an electronic component or a circuit board. It is preferable that the anisotropic conductive material is an anisotropic conductive paste, and the anisotropic conductive material is used in a paste state on an electronic component or a circuit board.

  The connection structure 1 shown in FIG. 1 can be obtained as follows, for example.

  As shown to Fig.2 (a), the 1st connection object member 2 which has the electrode 2b on the upper surface 2a is prepared. Next, an anisotropic conductive material including a plurality of conductive particles 5 is disposed on the upper surface 2a of the first connection target member 2, and the anisotropic conductive material layer 3A is disposed on the upper surface 2a of the first connection target member 2. Form. At this time, it is preferable that one or a plurality of conductive particles 5 be disposed on the electrode 2b. When an anisotropic conductive paste is used as the anisotropic conductive material, the anisotropic conductive paste is arranged by applying the anisotropic conductive paste. The anisotropic conductive material layer becomes an anisotropic conductive paste layer.

  Next, the anisotropic conductive material layer 3A is cured by irradiating the anisotropic conductive material layer 3A with light. By curing the anisotropic conductive material layer 3A, the anisotropic conductive material layer 3A is B-staged. As shown in FIG. 2B, the anisotropic conductive material layer 3 </ b> B having the B stage is formed on the upper surface 2 a of the first connection target member 2 by forming the anisotropic conductive material layer 3 </ b> A into the B stage. .

  When the anisotropic conductive material layer 3A is hardened and the anisotropic conductive material layer 3A is B-staged, the viscosity of the B-staged anisotropic conductive material layer 3B (hereinafter abbreviated as η3). The anisotropic conductive material layer 3A is preferably B-staged so that it is 2000 Pa · s or more and 15000 Pa · s or less. By setting the viscosity η3 to be equal to or higher than the lower limit and equal to or lower than the upper limit, the flow of the anisotropic conductive material layer can be sufficiently suppressed. For this reason, it becomes easy to arrange the conductive particles 5 between the electrodes 2b and 4b. Furthermore, it is possible to suppress the anisotropic conductive material layer from flowing unintentionally in a region lateral to the outer peripheral surface of the first connection target member 2 or the second connection target member 4.

  From the viewpoint of further suppressing the flow of the anisotropic conductive material layer and the conductive particles 5, the viscosity η3 is preferably 2000 Pa · s or more, preferably 2250 Pa · s or more, preferably 15000 Pa · s or less, more preferably 12000 Pa · s or less, more preferably 10,000 Pa · s or less, particularly preferably 3500 Pa · s or less, and most preferably 3250 Pa · s. The measurement temperature of the viscosity η3 is preferably 20 ° C. or higher, preferably 30 ° C. or lower. The measurement temperature of the viscosity η3 is particularly preferably 25 ° C.

  It is preferable to irradiate the anisotropic conductive material layer 3 </ b> A with light while disposing the anisotropic conductive material on the upper surface 2 a of the first connection target member 2. Furthermore, it is also preferable to irradiate the anisotropic conductive material layer 3 </ b> A simultaneously with or immediately after the placement of the anisotropic conductive material on the upper surface 2 a of the first connection target member 2. When the arrangement and the light irradiation are performed as described above, the flow of the anisotropic conductive material layer can be further suppressed. For this reason, the conduction | electrical_connection reliability in the obtained connection structure 1 can be improved further. The time from the placement of the anisotropic conductive material on the upper surface 2a of the first connection target member 2 to the irradiation with light is 0 second or longer, preferably 3 seconds or shorter, more preferably 2 seconds or shorter.

When the anisotropic conductive material layer 3A is B-staged by light irradiation, the light irradiation intensity for appropriately proceeding curing of the anisotropic conductive material layer 3A is preferably 0.1 to 100 mW, for example. / Cm ² or so.

  The light source used when irradiating light is not specifically limited. Examples of the light source include a light source having a sufficient light emission distribution at a wavelength of 420 nm or less. Specific examples of the light source include a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a chemical lamp, a black light lamp, a microwave excitation mercury lamp, and a metal halide lamp.

  Next, as shown in FIG. 2C, the second connection target member 4 is laminated on the upper surface 3a of the B-staged anisotropic conductive material layer 3B. The second connection target member 4 is laminated so that the electrode 2b on the upper surface 2a of the first connection target member 2 and the electrode 4b on the lower surface 4a of the second connection target member 4 face each other.

  Further, when the second connection target member 4 is laminated, the anisotropic conductive material layer 3B is further cured by applying heat to the anisotropic conductive material layer 3B, so that the connection portion 3 is formed. However, heat may be applied to the anisotropic conductive material layer 3B before the second connection target member 4 is laminated. Furthermore, it is preferable to apply heat to the anisotropic conductive material layer 3B and completely cure it after the second connection target member 4 is laminated.

  When the anisotropic conductive material layer 3B is cured by applying heat, the heating temperature for sufficiently curing the anisotropic conductive material layer 3B is preferably 160 ° C or higher, preferably 250 ° C or lower, more preferably It is 200 degrees C or less.

  It is preferable to apply pressure when the anisotropic conductive material layer 3B is cured. By compressing the conductive particles 5 with the electrodes 2b and 4b by pressurization, the contact area between the electrodes 2b and 4b and the conductive particles 5 can be increased. For this reason, conduction reliability can be improved.

  By curing the anisotropic conductive material layer 3 </ b> B, the first connection target member 2 and the second connection target member 4 are connected via the connection portion 3. Further, the electrode 2 b and the electrode 4 b are electrically connected through the conductive particles 5. In this way, the connection structure 1 shown in FIG. 1 can be obtained. In this embodiment, since photocuring and thermosetting are used together, the anisotropic conductive material can be cured in a short time.

  When obtaining the connection structure 1, the anisotropic conductive material layer 3A is irradiated with light to form a B-staged anisotropic conductive material layer 3B, and then heat is applied to the anisotropic conductive material layer 3B. It is preferable to do.

  The connection structure according to the present invention and the method for manufacturing the connection structure according to the present invention include, for example, connection between a flexible printed circuit board and a glass substrate (FOG (Film on Glass)), connection between a semiconductor chip and a flexible printed circuit board ( COF (Chip on Film)) or connection between a semiconductor chip and a glass substrate (COG (Chip on Glass)) or the like. Especially, the manufacturing method of the connection structure concerning the present invention and the connection structure concerning the present invention is suitable for COG use. In the connection structure according to the present invention and the method for manufacturing the connection structure according to the present invention, it is preferable to use a semiconductor chip and a glass substrate as the first connection target member and the second connection target member.

  In COG applications, in particular, it is often difficult to reliably connect the electrodes of the semiconductor chip and the glass substrate with conductive particles of an anisotropic conductive material. For example, in the case of COG use, the distance between adjacent electrodes of a semiconductor chip and the distance between adjacent electrodes of a glass substrate may be about 10 to 20 μm, and fine wiring is often formed. Even if fine wiring is formed, the conductive particles can be accurately arranged between the electrodes by the connection structure according to the present invention and the method for manufacturing the connection structure according to the present invention. The electrodes can be connected to the substrate with high accuracy, and the conduction reliability can be improved.

  Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. The present invention is not limited only to the following examples.

Example 1
(1) Preparation of anisotropic conductive paste Curable compound containing 20% by weight of methyl methacrylate which is a photo-curable compound and 80% by weight of epoxy acrylate which is a thermosetting compound (“EBECRYL 3702” manufactured by Daicel-Cytec) Prepared.

  100 parts by weight of the curable compound, 0.5 parts by weight of an acylphosphine oxide compound (“DAROCUR TPO” manufactured by Ciba Japan) as a photo radical initiator, and 2,2′-azobis as a thermal radical initiator 0.1 part by weight of 2,4-dimethylvaleronitrile (“V-65” manufactured by Wako Pure Chemical Industries, Ltd., decomposition temperature 51 ° C. for obtaining a 10-hour half-life) and an average particle diameter of 0.25 μm as a filler 20 parts by weight of silica and 20 parts by weight of alumina having an average particle diameter of 0.5 μm are blended, and further, conductive particles A having an average particle diameter of 3 μm are contained in 100% by weight of the blend so that the content becomes 10% by weight. Then, the mixture was stirred at 2000 rpm for 5 minutes using a planetary stirrer to obtain a blend.

  The conductive particles A used are conductive particles having a metal layer in which a nickel plating layer is formed on the surface of divinylbenzene resin particles and a gold plating layer is formed on the surface of the nickel plating layer. It is.

  The obtained blend was filtered using a nylon filter paper (pore diameter: 10 μm) to obtain an anisotropic conductive paste having a conductive particle content of 10% by weight.

(2) Production of Connection Structure A transparent glass substrate having an ITO electrode pattern with an L / S of 30 μm / 30 μm formed on the upper surface was prepared. Further, a semiconductor chip was prepared in which a copper electrode pattern having L / S of 30 μm / 30 μm was formed on the lower surface.

On the transparent glass substrate, the obtained anisotropic conductive paste was applied to a thickness of 30 μm to form an anisotropic conductive paste layer. Next, using an ultraviolet irradiation lamp for the anisotropic conductive paste layer, the ultraviolet irradiation of 420 nm is irradiated so that the light irradiation intensity is 50 mW / cm ² , the anisotropic conductive paste layer is semi-cured by photopolymerization, B stage. Next, the semiconductor chip was stacked on the anisotropic conductive paste layer so that the electrodes face each other. Then, while adjusting the temperature of the head so that the temperature of the anisotropic conductive paste layer becomes 185 ° C., a pressure heating head is placed on the upper surface of the semiconductor chip and a pressure of 3 MPa is applied to form the anisotropic conductive paste layer. Completely cured at 185 ° C. to obtain a connection structure.

(Example 2)
In the preparation of the anisotropic conductive paste, the conductive particles A were used in the same manner as in Example 1 except that the conductive particles A were used so that the content in 100% by weight of the blend was 5% by weight. An anisotropic conductive paste having a particle A content of 5% by weight was obtained. A connection structure was obtained in the same manner as in Example 1 except that the obtained anisotropic conductive paste was used.

(Example 3)
In the preparation of the anisotropic conductive paste, the conductive particles A were used in the same manner as in Example 1 except that the conductive particles A were used so that the content in 100% by weight of the blend was 15% by weight. An anisotropic conductive paste having a particle A content of 15% by weight was obtained. A connection structure was obtained in the same manner as in Example 1 except that the obtained anisotropic conductive paste was used.

Example 4
In the preparation of the anisotropic conductive paste, the conductive particles A were used in the same manner as in Example 1 except that the conductive particles A were used so that the content in 100% by weight of the blend was 1% by weight. An anisotropic conductive paste having a particle A content of 1% by weight was obtained. A connection structure was obtained in the same manner as in Example 1 except that the obtained anisotropic conductive paste was used.

(Example 5)
In the preparation of the anisotropic conductive paste, the thermal radical initiator is changed to tert-hexyl peroxypivalate (“Perhexyl PV” manufactured by NOF Corporation, decomposition temperature 54.6 ° C. for obtaining a half-life of 10 hours). An anisotropic conductive paste was obtained in the same manner as in Example 1 except that it was changed to. A connection structure was obtained in the same manner as in Example 1 except that the obtained anisotropic conductive paste was used.

(Example 6)
The anisotropic conductive paste was prepared in the same manner as in Example 1 except that the epoxy acrylate, which is a thermosetting compound, was changed to urethane acrylate ("EBECRYL8804" manufactured by Daicel-Cytec) when preparing the anisotropic conductive paste. A paste was obtained. A connection structure was obtained in the same manner as in Example 1 except that the obtained anisotropic conductive paste was used.

(Examples 7 to 12)
Divinylbenzene resin particles having an average particle diameter of 10 μm (“Micropearl SP-210” manufactured by Sekisui Chemical Co., Ltd.) were subjected to electroless nickel plating to form a base nickel plating layer having a thickness of 0.1 μm on the surface of the resin particles. Next, the resin particles on which the base nickel plating layer was formed were subjected to electrolytic copper plating to form a 1 μm thick copper layer. Furthermore, electrolytic plating was performed using an electrolytic plating solution containing tin and bismuth to form a solder layer having a thickness of 3 μm. Thus, a 1 μm thick copper layer is formed on the surface of the resin particles, and a 3 μm thick solder layer (tin: bismuth = 43 wt%: 57 wt%) is formed on the surface of the copper layer. Conductive particles B were prepared.

  In Example 7, the conductive particles A were changed to the conductive particles B, the filter paper used for the filtration was changed to nylon filter paper (pore diameter 30 μm), and the anisotropic conductive paste had a thickness of 40 μm. The anisotropic conductive paste and the connection structure were obtained in the same manner as in Example 1 except that the anisotropic conductive paste layer was formed.

  In Example 8, the conductive particles A were changed to the conductive particles B, the filter paper used for the filtration was changed to nylon filter paper (pore diameter 30 μm), and the anisotropic conductive paste had a thickness of 40 μm. The anisotropic conductive paste and the connection structure were obtained in the same manner as in Example 2 except that the anisotropic conductive paste layer was formed.

  In Example 9, the conductive particles A were changed to the conductive particles B, the filter paper used for the filtration was changed to nylon filter paper (pore diameter 30 μm), and the anisotropic conductive paste had a thickness of 40 μm. The anisotropic conductive paste and the connection structure were obtained in the same manner as in Example 3 except that the anisotropic conductive paste layer was formed.

  In Example 10, the conductive particles A were changed to the conductive particles B, the filter paper used for the filtration was changed to nylon filter paper (pore diameter 30 μm), and the anisotropic conductive paste had a thickness of 40 μm. The anisotropic conductive paste and the connection structure were obtained in the same manner as in Example 4 except that the anisotropic conductive paste layer was formed.

  In Example 11, the conductive particles A were changed to the conductive particles B, the filter paper used for the filtration was changed to nylon filter paper (pore diameter 30 μm), and the anisotropic conductive paste had a thickness of 40 μm. The anisotropic conductive paste and the connection structure were obtained in the same manner as in Example 5 except that the anisotropic conductive paste layer was formed.

  In Example 12, the conductive particles A were changed to the conductive particles B, the filter paper used for the filtration was changed to nylon filter paper (pore diameter 30 μm), and the anisotropic conductive paste had a thickness of 40 μm. The anisotropic conductive paste and the connection structure were obtained in the same manner as in Example 6 except that the anisotropic conductive paste layer was formed.

(Comparative Example 1)
In the preparation of the anisotropic conductive paste, anisotropy was carried out in the same manner as in Example 1 except that methyl methacrylate as a photocurable compound and acylphosphine oxide compound as a photoradical initiator were not used. Conductive paste was obtained. In 100% by weight of the obtained anisotropic conductive paste, the content of the conductive particles A was 10% by weight. A connection structure was obtained in the same manner as in Example 1 except that the obtained anisotropic conductive paste was used.

(Comparative Example 2)
The anisotropic conductive material obtained in Comparative Example 1 was prepared.

  A transparent glass substrate having an ITO electrode pattern with an L / S of 30 μm / 30 μm formed on the upper surface was prepared. Further, a semiconductor chip was prepared in which a copper electrode pattern having L / S of 30 μm / 30 μm was formed on the lower surface.

  On the upper surface of the transparent glass substrate, the obtained anisotropic conductive paste was applied from a syringe of a dispenser to a thickness of 30 μm to form an anisotropic conductive paste layer. During application and after application, light was not irradiated, thermal polymerization was not performed, and the anisotropic conductive material layer was not B-staged.

  Next, the semiconductor chip was stacked on the upper surface of the anisotropic conductive paste layer that was not B-staged so that the electrodes face each other. Then, while adjusting the temperature of the head so that the temperature of the anisotropic conductive paste layer becomes 185 ° C., a pressure heating head is placed on the upper surface of the semiconductor chip and a pressure of 3 MPa is applied to form the anisotropic conductive paste layer. Completely cured at 185 ° C. to obtain a connection structure.

(Comparative Example 3)
In the preparation of the anisotropic conductive paste, it was carried out except that epoxy acrylate as a thermosetting compound and 2,2′-azobis-2,4-dimethylvaleronitrile as a thermal radical initiator were not used. In the same manner as in Example 1, an anisotropic conductive paste was obtained. In 100% by weight of the obtained anisotropic conductive paste, the content of the conductive particles A was 10% by weight. A connection structure was obtained in the same manner as in Example 1 except that the obtained anisotropic conductive paste was used.

(Evaluation of Examples 1-12 and Comparative Examples 1-3)
(1) Viscosity Using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd.) under the conditions of 25 ° C. and 2.5 rpm, the obtained anisotropic conductive paste (viscosity of the anisotropic conductive paste before application) The viscosity η1 was measured. Moreover, viscosity η2 of the obtained anisotropic conductive paste was measured using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd.) at 25 ° C. and 5 rpm.

(2) Presence or absence of leakage Using the obtained connection structure, whether or not leakage occurred in 20 adjacent electrodes was measured with a tester.

(3) Presence / absence of voids In the obtained connection structure, whether or not voids were generated in the cured product layer formed of the anisotropic conductive paste layer was visually observed from the lower surface side of the transparent glass substrate.

(4) Viscosity of the B-staged anisotropic conductive paste layer After the anisotropic conductive paste layer is B-staged by photopolymerization, on the upper surface of the B-staged anisotropic conductive paste layer The viscosity η3 of the B-staged anisotropic conductive paste layer immediately before stacking the semiconductor chips was measured using a rheometer (manufactured by Anton Paar) at 25 ° C. and 2.5 rpm.

(5) Variation in coating width The obtained anisotropic conductive paste was filled into a syringe having a nozzle diameter of 1.1 mm, and using a dispenser, the pressure was 300 Pa, the coating thickness was 30 μm, the moving speed was 10 mm / s, the coating line distance was 20 mm, and An anisotropic conductive paste was applied on a glass substrate under the condition of an application width of 1 mm.

  The application width at each point of 2 mm, 5 mm, and 10 mm from the application start point of the anisotropic conductive paste was measured with a microscope with a length measuring function.

(6) Height (thickness) of cured product layer (connection part)
An anisotropic conductive paste was applied on a glass substrate in the same manner as in the evaluation of (5) above. Immediately after the application, ultraviolet rays were irradiated to initiate photocuring of the anisotropic conductive paste. Furthermore, 10 seconds after the irradiation of the ultraviolet rays, the glass substrate coated with the anisotropic conductive paste was placed in an oven at 150 ° C. for 5 minutes to thermally cure the anisotropic conductive paste. The height of the cured product layer formed by curing the anisotropic conductive paste was measured with a micrometer.

  The results are shown in Tables 1 and 2 below.

DESCRIPTION OF SYMBOLS 1 ... Connection structure 2 ... 1st connection object member 2a ... Upper surface 2b ... Electrode 3 ... Connection part 3a ... Upper surface 3A ... Anisotropic conductive material layer 3B ... B-staged anisotropic conductive material layer 4 ... First 2 connection target members 4a ... lower surface 4b ... electrode 5 ... conductive particles

Claims (10)

It is a B-stage product of an anisotropic conductive material that is an anisotropic conductive material irradiated with light,
The anisotropic conductive material contains a curable compound, a thermal radical initiator, a photo radical initiator, and conductive particles ,
The decomposition temperature for obtaining the 10-hour half-life of the thermal radical initiator is 30 ° C. or higher and 80 ° C. or lower,
Viscosity at 25 ° C. and 2.5rpm in a B-stage product of the anisotropic conductive material is 2000 Pa · s or more, Ru der following 15000Pa · s, B-stage product of the anisotropic conductive material. The B-staged product of the anisotropic conductive material according to claim 1, wherein the curable compound includes a curable compound having a (meth) acryloyl group. The anisotropic conductive material containing a curable compound, a thermal radical initiator, a photo radical initiator, and conductive particles is irradiated with light to advance curing, and a B-stage product of the anisotropic conductive material A step of obtaining
The decomposition temperature for obtaining the 10-hour half-life of the thermal radical initiator is 30 ° C. or higher and 80 ° C. or lower,
A method for producing a B-staged product of an anisotropic conductive material, wherein the B-staged product of the anisotropic conductive material has a viscosity at 25 ° C. and 2.5 rpm of 2000 Pa · s to 15000 Pa · s. The method for producing a B-staged product of an anisotropic conductive material according to claim 3, wherein the curable compound contains a curable compound having a (meth) acryloyl group. The method for producing a B-staged product of an anisotropic conductive material according to claim 3 or 4, wherein the anisotropic conductive material has a viscosity at 25 ° C and 2.5 rpm of 20 Pa · s or more and 200 Pa · s or less. . When the viscosity at 25 ° C. and 2.5 rpm of the anisotropic conductive material is η1, and the viscosity at 25 ° C. and 5 rpm is η2, the η2 is 20 Pa · s or more and 200 Pa · s or less, The ratio of the η1 to the η2 (η1 / η2) is 0.9 or more and 1.1 or less, and the production of the B-staged product of the anisotropic conductive material according to any one of claims 3 to 5. Method. The method for producing a B-staged product of an anisotropic conductive material according to any one of claims 3 to 6, wherein the anisotropic conductive material is a paste-like anisotropic conductive paste. The curable compound, the thermal radical initiator, the photo radical initiator, and the conductive particles are stirred to obtain an anisotropic conductive material according to any one of claims 3 to 7. A method for producing a B-stage product of an anisotropic conductive material. A first connection target member, a second connection target member, and a connection portion that electrically connects the first and second connection target members;
The connecting portion, Ru cured der B-stage product of the anisotropic conductive material according to claim 1 or 2, the connection structure. A step of forming a B-staged product of anisotropic conductive material on the upper surface of the first connection target member by the method for producing a B-staged product of anisotropic conductive material according to any one of claims 3 to 8. When,
And a step of further laminating a second connection target member on the upper surface of the B-staged product of the anisotropic conductive material .

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