JP7328858B2 - Conductive particles, conductive materials and connecting structures - Google Patents

Description

TECHNICAL FIELD The present invention relates to conductive particles that can be used for electrical connection between electrodes and the like. The present invention also relates to a conductive material and a connection structure using the conductive particles.

Anisotropic conductive materials such as anisotropic conductive pastes and anisotropic conductive films are widely known. In the anisotropic conductive material, conductive particles are dispersed in a binder resin. Further, as the conductive particles, conductive particles having a substrate particle and a conductive portion arranged on the surface of the substrate particle may be used.

The anisotropic conductive material is used to obtain various connection structures. Connection using the anisotropic conductive material includes 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)), semiconductor chip and a glass substrate (COG (Chip on Glass)), and a flexible printed circuit board and a glass epoxy substrate (FOB (Film on Board)).

The conductive particles that can be used in the anisotropic conductive material are disclosed in Patent Documents 1 to 3 below.

Patent Document 1 below discloses a conductive particle comprising a substrate particle and a conductive layer provided on the surface of the substrate particle. The conductive layer has a structure in which a metal layer containing nickel and a conductive layer containing gold or palladium are sequentially laminated. The conductive layer has a thickness of 10 nm or less. The conductive particles have an alkyl group having 6 to 22 carbon atoms on the surface. Since the conductive particles have an alkyl group having 6 to 22 carbon atoms on the surface, the surfaces of the conductive particles are hydrophobic. Patent Document 1 describes that even if the nickel-containing metal layer is exposed, the metal layer is less likely to be corroded, preventing the connection resistance of the conductive particles from increasing.

The following Patent Document 2 discloses a conductive particle body having a resin particle and a conductive layer provided on the surface of the resin particle, and a coating layer covering the surface of the conductive particle body. Conductive particles are disclosed. The coating layer is formed by cross-linking an organic silicon compound. Patent Document 2 describes that the hydrophilicity of the surface of the conductive particles can be increased, and that the dispersibility of the conductive particles in an oxygen-containing resin such as an epoxy resin can be increased. .

Patent Literature 3 below discloses a conductive particle comprising a particle having at least a conductive portion on the surface thereof, and a coating film disposed on the outer surface of the conductive portion. The coating has a non-polar group and a polar group. In Patent Document 3, when the electrodes are connected using the conductive particles, it is possible to improve the reliability of conduction between the electrodes, and the conductive particles can be dispersed well in the binder resin. It states what you can do.

JP 2010-086664 A JP 2012-003917 A JP 2013-214509 A

In Patent Document 1, the surface of the conductive particles is hydrophobic because the conductive particles have an alkyl group having 6 to 22 carbon atoms on the surface, so that the initial connection resistance after conductive connection is reduced to some extent. Furthermore, the reliability of conduction after long-term use can be improved to some extent. In addition, in Patent Documents 2 and 3, the dispersibility of the conductive particles can be improved, so the initial connection resistance after conductive connection can be reduced to some extent, and the conduction reliability after long-term use can be improved to some extent. be able to.

However, in recent years, the density and performance of electronic devices have been increasing, and further reduction in connection resistance and further improvement in conduction reliability have been demanded.

In Patent Document 1, the dispersibility of the conductive particles in the binder resin is low, so it is difficult to considerably improve the conduction reliability. The reason for this is that moisture easily penetrates into the interface between the conductive particles and the binder resin.

Even in Patent Documents 2 and 3, it is difficult to achieve both a considerably low initial connection resistance and a considerable increase in conduction reliability.

An object of the present invention is to provide conductive particles capable of enhancing conduction reliability after long-term use. A limited object of the present invention is to provide conductive particles that can effectively reduce the initial connection resistance after conductive connection and further improve the conduction reliability after long-term use. Another object of the present invention is to provide a conductive material and a connection structure using the conductive particles.

According to a broad aspect of the invention, there is provided a conductive particle having a conductive portion and having at least two organosilicon functional groups on the outer surface of said conductive portion.

In a specific aspect of the conductive particles according to the present invention, the outer surface of the conductive portion has an organosilicon functional group having a (meth)acryloyl group.

In a specific aspect of the conductive particles according to the present invention, the outer surface of the conductive portion has an organosilicon functional group having an epoxy group.

In a specific aspect of the conductive particles according to the present invention, the outer surface of the conductive portion has an organosilicon functional group having an alkyl group having 1 or more and 22 or less carbon atoms.

In a specific aspect of the conductive particles according to the present invention, the outer surface of the conductive portion has an organosilicon functional group having an antirust effect.

In a specific aspect of the conductive particles according to the present invention, the organosilicon functional group having an antirust effect is an organosilicon functional group having a benzotriazole group.

In a specific aspect of the conductive particles according to the present invention, the outer surface of the conductive portion has an organic silicon functional group having an antirust effect, an organic silicon functional group having a (meth)acryloyl group, and an organic silicon functional group having an epoxy group. and at least one organosilicon functional group of the silicon functional groups.

In a specific aspect of the conductive particles according to the present invention, the organosilicon functional groups having the (meth)acryloyl group and the organosilicon functional groups having the epoxy group are is 0.05 or more and 0.95 or less.

In a specific aspect of the conductive particle according to the present invention, the outer surface of the conductive portion has an organosilicon functional group having a (meth)acryloyl group and an organosilicon functional group having an epoxy group.

In a specific aspect of the conductive particles according to the present invention, the surface area covered with at least two organosilicon functional groups is 60% or more and 100% or less of 100% of the surface area of the conductive portion.

In a specific aspect of the conductive particles according to the present invention, the conductive particles comprise substrate particles and conductive portions arranged on the surfaces of the substrate particles.

In a specific aspect of the conductive particles according to the present invention, the conductive particles have protrusions on the outer surface of the conductive portion.

In a specific aspect of the conductive particles according to the present invention, the conductive particle body includes an insulating substance arranged on the outer surface of the conductive portion.

According to a broad aspect of the present invention, there is provided a conductive material containing the conductive particles described above and a binder resin.

According to a broad aspect of the present invention, a first member to be connected having a first electrode on its surface; a second member to be connected having a second electrode on its surface; a connecting portion that connects the second connection target member, and the material of the connecting portion is the above-described conductive particles, or a conductive material containing the conductive particles and a binder resin; A connection structure is provided in which the first electrode and the second electrode are electrically connected by the conductive particles.

The conductive particles according to the present invention have a conductive portion and have at least two organosilicon functional groups on the outer surface of the conductive portion. Since the conductive particles according to the present invention have the above configuration, the reliability of conduction after long-term use can be improved.

FIG. 1 is a cross-sectional view showing conductive particles according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view showing conductive particles according to a second embodiment of the present invention. FIG. 3 is a cross-sectional view showing conductive particles according to a third embodiment of the present invention. FIG. 4 is a cross-sectional view showing conductive particles according to a fourth embodiment of the present invention. FIG. 5 is a front cross-sectional view schematically showing a connection structure using conductive particles according to the first embodiment of the present invention.

The details of the present invention are described below.

(Conductive particles)
The conductive particles according to the present invention have a conductive portion and have at least two organosilicon functional groups on the outer surface of the conductive portion.

Since the conductive particles according to the present invention have the above configuration, the initial connection resistance after conductive connection can be effectively reduced, and the reliability of conduction after long-term use can be improved. .

An "organosilicon functional group" includes carbon atoms and silicon atoms. The organosilicon functional group is represented, for example, by the following formula (1).

In formula (1) above, X1, X2 and X3 each independently represent a non-hydrolyzable group, a hydrolyzable group, another organosilicon functional group or a hydrogen atom. Also, at least one of X1, X2 and X3 is a non-hydrolyzable group. When X1, X2 or X3 is an organosilicon functional group, for example, a siloxane bond in which two Si are connected via -O-, or two silicon bonds via a chemical bond such as -Si-Si- It refers to a state in which different organosilicon functional groups are connected starting from an atom. X1, X2 and X3 may be the same or different. Also, the remaining bonds that are not bonded to any of X1, X2 and X3 of the Si atoms bond to the outer surface of the conductive portion itself or a substance (such as a film) placed on the outer surface of the conductive portion.

An alkoxy group etc. are mentioned as said hydrolyzable group. Specific examples of the alkoxy group include alkoxy groups having 1 to 6 carbon atoms. The alkoxy group having 1 to 6 carbon atoms includes methoxy group, ethoxy group and propoxy group.

The hydrolyzable group may be a hydrolyzable group other than an alkoxy group. Specific examples of hydrolyzable groups other than the alkoxy groups include halogen groups such as chlorine or bromine, acetyl groups, hydroxyl groups, isocyanate groups, and the like.

Examples of the non-hydrolyzable organic group include organic groups having 1 to 30 carbon atoms which are hardly hydrolyzed and are stable hydrophobic groups.

The organic group having 1 to 30 carbon atoms includes an alkyl group having 1 to 30 carbon atoms, a halogenated alkyl group, an aromatic substituted alkyl group, an aryl group, an organic group containing a vinyl group, an organic group containing an epoxy group, ( Meth) acryloyl group-containing organic groups, benzotriazole group-containing organic groups, amino group-containing organic groups, thiol group-containing organic groups, and the like.

Examples of the alkyl group having 1 to 30 carbon atoms include methyl group, ethyl group, propyl group, butyl group, hexyl group, cyclohexyl group, octyl group, pentyl group, decyl group, dodecyl group, tetradecyl group, hexadecyl group and octadecyl group. and an eicosyl group. Examples of the halogenated alkyl group include a fluoride group of an alkyl group, a chloride group of an alkyl group and a bromide group of an alkyl group. Specific examples of the halogenated alkyl group include, for example, 3-chloropropyl group, 6-chloropropyl group, 6-chlorohexyl group and 6,6,6-trifluorohexyl group. Examples of the aromatic-substituted alkyl group include a benzyl group and a halogen-substituted benzyl group. Examples of the halogen-substituted benzyl group include 4-chlorobenzyl group and 4-bromobenzyl group. Examples of the aryl group include phenyl group, tolyl group, mesityl group and naphthyl group.

At least two of the above organosilicon functional groups can be introduced using at least two organosilicon compounds. The at least two organosilicon functional groups may be introduced by reacting at least two organosilicon compounds with each other. Using a first organosilicon compound and a second organosilicon compound, a first organosilicon functional group derived from the first organosilicon compound and a second organosilicon functional group derived from the second organosilicon compound functional groups may be introduced. Using the first organosilicon compound, the second organosilicon compound and the third organosilicon compound, the first organosilicon functional group derived from the first organosilicon compound and the second organosilicon compound A second organosilicon functional group derived from a third organosilicon compound and a third organosilicon functional group derived from a third organosilicon compound may be introduced. A first organosilicon compound, a second organosilicon compound, a third organosilicon compound, and a fourth organosilicon compound may be used. In this case, the first organosilicon functional group derived from the first organosilicon compound, the second organosilicon functional group derived from the second organosilicon compound, and the third organosilicon functional group derived from the third organosilicon compound Three organosilicon functional groups and a fourth organosilicon functional group derived from a fourth organosilicon compound may be introduced. The first organosilicon functional group and the second organosilicon functional group may be reactants of the first organosilicon compound and the second organosilicon compound. The first organosilicon functional group, the second organosilicon functional group, and the third organosilicon functional group are reactants of the first organosilicon compound, the second organosilicon compound, and the third organosilicon compound. may be The first organosilicon functional group, the second organosilicon functional group, the third organosilicon functional group, and the fourth organosilicon functional group are the first organosilicon compound, the second organosilicon compound, and the third organosilicon functional group. It may be a reaction product of an organosilicon compound and a fourth organosilicon compound.

Specific examples of the organosilicon compounds include triphenylethoxysilane, trimethylethoxysilane, triethylethoxysilane, triphenylmethoxysilane, triethylmethoxysilane, ethyldimethylmethoxysilane, methyldiethylmethoxysilane, ethyldimethylethoxysilane, methyl diethylethoxysilane, phenyldimethylmethoxysilane, phenyldiethylmethoxysilane, phenyldimethylethoxysilane, phenyldiethylethoxysilane, methyldiphenylmethoxysilane, ethyldiphenylmethoxysilane, methyldiphenylethoxysilane, ethyldiphenylethoxysilane, tert-butoxytrimethylsilane, butoxytrimethylsilane, dimethylethoxysilane, methoxydimethylvinylsilane, ethoxydimethylvinylsilane, diphenyldiethoxysilane, phenyldiethoxysilane, dimethyldimethoxysilane, diacetoxymethylsilane, diethoxymethylsilane, 3-chloropropyldimethoxymethylsilane, chloromethylsilane Diethoxymethylsilane, diethoxydimethylsilane, diacetoxymethylvinylsilane, diethoxymethylvinylsilane, diethoxydiethylsilane, dimethyldipropoxysilane, dimethoxymethylphenylsilane, methyltrimethoxysilane, methyltriethoxysilane, methyl-tri-n -propoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyl-tri-n-propoxysilane, propyltrimethoxysilane, propyltriethoxysilane, propyl-tri-n-propoxysilane, butyltrimethoxysilane, butyltriethoxysilane Silane, butyltripropoxysilane, isobutyltrimethoxysilane, isobutyltriethoxysilane, isobutyltripropoxysilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, n-hexyltripropoxysilane, cyclohexyltrimethoxysilane, cyclohexyltri ethoxysilane, cyclohexyltripropoxysilane, octyltrimethoxysilane, octyltriethoxysilane, octyltripropoxysilane, dodecyltrimethoxysilane, dodecyltriethoxysilane, dodecyltripropoxysilane, tetradecyltrimethoxysilane, tetradecyltriethoxysilane, Tetradecyltripropoxysilane, hexadecyltrimethoxysilane, hexadecyltriethoxysilane, hexadecyltripropoxysilane, octadecyltrimethoxysilane, octadecyltriethoxysilane, octadecyltripropoxysilane, eicosyldecyltrimethoxysilane, eicosyltriethoxysilane Silane, eicosyltripropoxysilane, 6-chlorohexyltrimethoxysilane, 6,6,6-trifluorohexyltrimethoxysilane, benzyltrimethoxysilane, 4-chlorobenzyltrimethoxysilane, 4-bromobenzyltri-n- Propoxysilane, Phenyltrimethoxysilane, Phenyltriethoxysilane, Vinyltrimethoxysilane, Vinyltriethoxysilane, 2-(3,4-Epoxycyclohexyl)ethyltrimethoxysilane, 3-Glycidoxypropyltrimethoxysilane, 3- glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyl Diethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3- aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1, 3-dimethyl-butylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltri ethoxysilane, 3-isocyanatopropyltriethoxysilane, triethoxysilane, trimethoxysilane, triisopropoxysilane, tri-n-propoxysilane, triacetoxysilane, tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, Examples include tetraisopropoxysilane and tetraacetoxysilane.

At least two of the organosilicon functional groups may be bonded together. At least two of the organosilicon functional groups may be linked by a siloxane bond.

In the binder resin containing acrylic resin as a main component, from the viewpoint of improving the adhesion of the interface between the conductive particles and the binder resin and further increasing the connection reliability, the conductive particles are added to the outer surface of the conductive portion. preferably has an organosilicon functional group having a (meth)acryloyl group. In this case, the conductive particles further have an organosilicon functional group other than the organosilicon functional group having a (meth)acryloyl group on the outer surface of the conductive portion. The organosilicon functional group having a (meth)acryloyl group is preferably introduced by an organosilicon compound having a (meth)acryloyl group. The organosilicon functional group having a (meth)acryloyl group is preferably an organosilicon functional group derived from an organosilicon compound having a (meth)acryloyl group. An organosilicon functional group having a (meth)acryloyl group preferably has a (methacryloyl group) bonded to a silicon atom.

Examples of the organosilicon compound having a (meth)acryloyl group include 3-methacryloxypropyltrimethoxysilane, 3-acryloxytrimethoxysilane and 8-methacryloxytrimethoxysilane.

In the binder resin containing epoxy resin as a main component, from the viewpoint of improving the adhesion of the interface between the conductive particles and the binder resin and further increasing the connection reliability, the conductive particles are added to the outer surface of the conductive portion. Preferably, it has an organosilicon functional group with an epoxy group. In this case, the conductive particles further have an organosilicon functional group other than the organosilicon functional group having an epoxy group on the outer surface of the conductive portion. The organosilicon functional group having an epoxy group is preferably introduced by an organosilicon compound having an epoxy group. The organosilicon functional group having an epoxy group is preferably an organosilicon functional group derived from an organosilicon compound having an epoxy group. The organosilicon functional group having an epoxy group preferably has an epoxy group bonded to a silicon atom.

Examples of the organosilicon compound having an epoxy group include 3-glycidoxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and 8-glycidoxyoctyltrimethoxysilane.

In the binder resin containing an acrylic resin and an epoxy resin, from the viewpoint of improving the adhesion of the interface between the conductive particles and the binder resin and further increasing the connection reliability, the conductive particles are provided outside the conductive portion. It is preferable that the surface has an organosilicon functional group having a (meth)acryloyl group and an organosilicon functional group having an epoxy group.

From the viewpoint of further increasing connection reliability by improving corrosion resistance and preventing deterioration on the surface of the conductive particles, the conductive particles have an alkyl group having 1 or more and 22 or less carbon atoms on the outer surface of the conductive portion. It is preferred to have an organosilicon functional group with In this case, the conductive particles further have an organosilicon functional group other than the organosilicon functional group having an alkyl group having 1 to 22 carbon atoms on the outer surface of the conductive portion. In the organosilicon functional group having an alkyl group having 1 to 22 carbon atoms, the alkyl group has 1 to 22 carbon atoms. The number of carbon atoms in the alkyl group is preferably 3 or more, preferably 18 or less, from the viewpoint of further improving the conduction reliability after long-term use by improving the corrosion resistance of the surface of the conductive particles and preventing deterioration.

From the viewpoint of further increasing the reliability of conduction after long-term use by improving the corrosion resistance and preventing deterioration on the surface of the conductive particles, the conductive particles contain organic silicon having a rust-preventive effect on the outer surface of the conductive portion. It preferably has a functional group. In this case, the conductive particles further have an organosilicon functional group other than the organosilicon functional group having an antirust effect on the outer surface of the conductive portion. It is preferable that the organosilicon functional group having an antirust effect is introduced by an organosilicon compound having a group having an antirust effect. The organosilicon functional group having an antirust effect is preferably an organosilicon functional group derived from an organosilicon compound having a group having an antirust effect. The organosilicon functional group having a rust-preventing effect preferably has a group having a rust-preventing effect bonded to a silicon atom.

Benzotriazolemethyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, trifluoropropyltrimethoxysilane and the like are examples of the organosilicon compound having a group having an antirust effect.

Groups having an antirust effect include benzotriazole groups, mercapto groups, trifluoroalkyl groups, and the like.

From the viewpoint of further increasing the conduction reliability after long-term use, the organosilicon functional group having a rust-preventing effect is preferably an organosilicon functional group having a benzotriazole group. The organosilicon functional group having a benzotriazole group is preferably introduced by an organosilicon compound having a benzotriazole group. The organosilicon functional group having a benzotriazole group is preferably an organosilicon functional group derived from an organosilicon compound having a benzotriazole group. Organosilicon functional groups having benzotriazole groups preferably have benzotriazole groups bonded to silicon atoms.

From the viewpoint of improving the adhesion at the interface between the conductive particles and the binder resin, and further increasing the reliability of conduction after long-term use by improving corrosion resistance and preventing deterioration on the surfaces of the conductive particles, the conductive particles are: An organosilicon functional group having an antirust effect and at least one of an organosilicon functional group having a (meth)acryloyl group and an organosilicon functional group having an epoxy group are formed on the outer surface of the conductive portion. It is preferred to have

The ratio (X) is the ratio of the number of the organosilicon functional groups having the antirust effect to the total number of the organosilicon functional groups having the (meth)acryloyl group and the organosilicon functional groups having the epoxy group. . From the viewpoint of further increasing the conduction reliability after long-term use by improving corrosion resistance and preventing deterioration on the surface of the conductive particles, the ratio (X) is preferably 0.05 or more, more preferably 0.10 or more, It is preferably 0.95 or less, more preferably 0.90 or less.

The ratio (X1) is the ratio of the number of the organosilicon functional groups having the benzotriazole group to the total number of the organosilicon functional groups having the (meth)acryloyl group and the organosilicon functional groups having the epoxy group. . From the viewpoint of further increasing connection reliability by improving corrosion resistance and preventing deterioration on the surface of the conductive particles, the ratio (X1) is preferably 0.05 or more, more preferably 0.10 or more, and preferably 0. 0.95 or less, more preferably 0.90 or less.

Among the organosilicon functional groups described above, the organosilicon functional group having a benzotriazole group mainly plays a role of improving corrosion resistance and preventing deterioration on the surface of the conductive particles, and enhances conduction reliability after long-term use. .

Among the organosilicon functional groups described above, the organosilicon functional group having a (meth)acryloyl group or an epoxy group mainly serves to improve the adhesion between the surface of the conductive particles and the interface of the binder resin, thereby Increase reliability.

By introducing organosilicon functional groups having different roles, the initial connection resistance after conductive connection can be more effectively reduced, and the conduction reliability after long-term use can be further enhanced.

From the viewpoint of further lowering the initial connection resistance after conductive connection and further increasing the reliability of conduction after long-term use, it is desirable that 100% of the surface area of the conductive portion is covered with at least two types of organic silicon functional groups. The surface area covered is preferably 60% or more, more preferably 80% or more, and preferably 100% or less. Of 100% of the surface area of the conductive portion, the surface area covered with at least two types of organosilicon functional groups may be 97.5% or less, or may be 95% or less.

The particle size of the conductive particles is preferably 0.1 μm or more, more preferably 1 μm or more, and preferably 1000 μm or less, more preferably 100 μm or less, and even more preferably 10 μm or less. When the particle diameter of the conductive particles is the lower limit or more and the upper limit or less, when the electrodes are connected using the conductive particles, the contact area between the conductive particles and the electrodes is sufficiently large, In addition, it becomes difficult to form agglomerated conductive particles when forming the conductive portion. In addition, the distance between the electrodes connected via the conductive particles does not become too large, and the conductive portions are less likely to peel off from the surface of the substrate particles.

The particle size of the conductive particles is preferably an average particle size, more preferably a number average particle size. The particle size of the conductive particles can be obtained, for example, by observing 50 arbitrary conductive particles with an electron microscope or an optical microscope and calculating the average particle size of each conductive particle, or by using a particle size distribution measuring device. is obtained using In observation with an electron microscope or an optical microscope, the particle size of each conductive particle is obtained as the particle size in circle equivalent diameter. In observation with an electron microscope or an optical microscope, the average particle size of arbitrary 50 conductive particles in equivalent circle diameter is almost equal to the average particle size in equivalent sphere diameter. In the particle size distribution analyzer, the particle size of each conductive particle is obtained as the particle size in terms of equivalent sphere diameter. The average particle size of the conductive particles is preferably calculated using a particle size distribution analyzer.

The coefficient of variation (CV value) of the particle size of the conductive particles is preferably 10% or less, more preferably 5% or less. When the coefficient of variation of the particle size of the conductive particles is equal to or less than the upper limit, the reliability of electrical connection and the reliability of insulation between electrodes can be more effectively improved.

The coefficient of variation (CV value) can be measured as follows.

CV value (%) = (ρ/Dn) × 100
ρ: standard deviation of the particle size of the conductive particles Dn: average value of the particle size of the conductive particles

The shape of the conductive particles is not particularly limited. The shape of the conductive particles may be spherical, may be other than spherical, or may be flat.

Hereinafter, the present invention will be specifically described with reference to the drawings. In addition, in FIG. 1 and the figures described later, different parts can be replaced with each other.

FIG. 1 is a cross-sectional view showing conductive particles according to a first embodiment of the present invention.

A conductive particle 1 shown in FIG. 1 has a substrate particle 2 and a conductive portion 3 . The conductive portion 3 is arranged on the surface of the substrate particle 2 . In the first embodiment, the conductive portion 3 is in contact with the surface of the substrate particles 2 . The conductive particles 1 are coated particles in which the surfaces of the base particles 2 are coated with the conductive portions 3 .

In the conductive particles 1, the conductive portion 3 is a single conductive layer. In the conductive particles, the conductive portion may cover the entire surface of the substrate particle, or the conductive portion may cover a portion of the surface of the substrate particle. In the conductive particles, the conductive part may be a single-layer conductive layer, or may be a multi-layer conductive layer composed of two or more layers.

The conductive particles 1 do not have a core substance, unlike the conductive particles 11 and 21 described later. The conductive particles 1 do not have protrusions on their surfaces. Conductive particles 1 are spherical. The conductive portion 3 does not have protrusions on its outer surface. Thus, the conductive particles according to the present invention may have no projections on the conductive surface, and may be spherical. Also, unlike the conductive particles 11 and 21 to be described later, the conductive particles 1 do not have an insulating substance. However, the conductive particles 1 may have an insulating substance arranged on the outer surface of the conductive portion 3 .

FIG. 2 is a cross-sectional view showing conductive particles according to a second embodiment of the present invention.

A conductive particle 11 shown in FIG. 2 has a substrate particle 2 , a conductive portion 12 , a plurality of core substances 13 , and a plurality of insulating substances 14 . The conductive portion 12 is arranged on the surface of the substrate particle 2 so as to be in contact with the substrate particle 2 .

In the conductive particles 11, the conductive portion 12 is a single conductive layer. In the conductive particles, the conductive portion may cover the entire surface of the substrate particle, or the conductive portion may cover a portion of the surface of the substrate particle. In the conductive particles, the conductive part may be a single-layer conductive layer, or may be a multi-layer conductive layer composed of two or more layers.

The conductive particles 11 have a plurality of projections 11a on their conductive surfaces. The conductive portion 12 has a plurality of protrusions 12a on its outer surface. A plurality of core substances 13 are arranged on the surface of the substrate particles 2 . A plurality of core substances 13 are embedded in the conductive portion 12 . The core substance 13 is arranged inside the protrusions 11a and 12a. The conductive portion 12 covers a plurality of core substances 13 . The outer surface of the conductive portion 12 is raised by a plurality of core substances 13 to form projections 11a and 12a.

The conductive particles 11 have an insulating material 14 disposed on the outer surface of the conductive portion 12 . At least a partial region of the outer surface of the conductive portion 12 is covered with an insulating material 14 . The insulating substance 14 is made of an insulating material and is an insulating particle. Thus, the conductive particles according to the present invention may have an insulating material arranged on the outer surface of the conductive portion. However, the conductive particles according to the present invention may not necessarily contain an insulating substance.

FIG. 3 is a cross-sectional view showing conductive particles according to a third embodiment of the present invention.

A conductive particle 21 shown in FIG. 3 has a substrate particle 2 , a conductive portion 22 , a plurality of core substances 13 , and a plurality of insulating substances 14 . The conductive portion 22 as a whole has a first conductive portion 22A on the substrate particle 2 side and a second conductive portion 22B on the side opposite to the substrate particle 2 side.

The conductive particles 11 and 21 differ only in the conductive portion. That is, in the conductive particles 11, the conductive portion 12 having a single-layer structure is formed, whereas in the conductive particles 21, the first conductive portion 22A and the second conductive portion 22B having a two-layer structure are formed. ing. The first conductive portion 22A and the second conductive portion 22B are formed as separate conductive portions.

22 A of 1st electroconductive parts are arrange|positioned on the surface of the base-material particle 2. As shown in FIG. A first conductive portion 22A is arranged between the substrate particle 2 and the second conductive portion 22B. The first conductive portion 22A is in contact with the substrate particles 2 . The second conductive portion 22B is in contact with the first conductive portion 22A. Therefore, the first conductive portion 22A is arranged on the surface of the substrate particle 2, and the second conductive portion 22B is arranged on the surface of the first conductive portion 22A. The conductive particles 21 have a plurality of projections 21a on their conductive surfaces. The conductive portion 22 has a plurality of protrusions 22a on its outer surface. The first conductive portion 22A has a plurality of protrusions 22Aa on its outer surface. The second conductive portion 22B has a plurality of projections 22Ba on its outer surface.

FIG. 4 is a cross-sectional view showing conductive particles according to a fourth embodiment of the present invention.

The conductive particles 31 shown in FIG. 4 are entirely conductive portions. Both the central portion and the surface portion of the conductive particles 31 are formed of conductive portions. Conductive particles 31 do not have substrate particles.

Conductive particles 1, 11 and 21 have at least two types of organosilicon functional groups on the outer surfaces of conductive portions 3, 12 and 22, respectively. The conductive particles 31, which are the conductive portion, have at least two organosilicon functional groups on the outer surface. At least two organosilicon functional groups may be formed as a coating disposed on the outer surface of the conductive portion.

Other details of the conductive particles are described below.

(Base particles)
The material of the substrate particles is not particularly limited. The material of the substrate particles may be an organic material or an inorganic material. Examples of the substrate particles formed only from the organic material include resin particles. Examples of the substrate particles formed only from the inorganic material include inorganic particles other than metals. Organic-inorganic hybrid particles and the like are examples of base particles formed from both the above-mentioned organic material and the above-mentioned inorganic material. From the viewpoint of further reducing the initial connection resistance and further increasing the conduction reliability, the substrate particles are preferably resin particles or organic-inorganic hybrid particles, more preferably resin particles.

The substrate particles may not be metal particles.

Examples of the organic material include polyolefin resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyisobutylene, and polybutadiene; acrylic resins such as polymethyl methacrylate and polymethyl acrylate; polycarbonates, polyamides, phenol formaldehyde resins, and melamine. Formaldehyde resin, benzoguanamine formaldehyde resin, urea formaldehyde resin, phenol resin, melamine resin, benzoguanamine resin, urea resin, epoxy resin, unsaturated polyester resin, saturated polyester resin, polyethylene terephthalate, polysulfone, polyphenylene oxide, polyacetal, polyimide, polyamideimide, Examples include polyetheretherketone, polyethersulfone, divinylbenzene polymer, and divinylbenzene copolymer. Examples of the divinylbenzene copolymer and the like include a divinylbenzene-styrene copolymer and a divinylbenzene-(meth)acrylate copolymer. Since the compression characteristics of the substrate particles can be easily controlled within a suitable range, the material of the substrate particles is a polymer obtained by polymerizing one or more polymerizable monomers having an ethylenically unsaturated group. is preferred.

When the substrate particles are obtained by polymerizing a polymerizable monomer having an ethylenically unsaturated group, the polymerizable monomer having an ethylenically unsaturated group includes a non-crosslinking monomer and a crosslinkable monomer. and monomers of the same type.

Examples of the non-crosslinkable monomers include vinyl compounds such as styrene monomers such as styrene, α-methylstyrene, and chlorostyrene; vinyl ether compounds such as methyl vinyl ether, ethyl vinyl ether, and propyl vinyl ether; vinyl acetate, vinyl butyrate, Acid vinyl ester compounds such as vinyl laurate and vinyl stearate; halogen-containing monomers such as vinyl chloride and vinyl fluoride; ) Alkyl ( meth) acrylate compounds; oxygen atom-containing (meth) acrylate compounds such as 2-hydroxyethyl (meth) acrylate, glycerol (meth) acrylate, polyoxyethylene (meth) acrylate, glycidyl (meth) acrylate; (meth) acrylonitrile and the like Nitrile-containing monomers; halogen-containing (meth)acrylate compounds such as trifluoromethyl (meth)acrylate and pentafluoroethyl (meth)acrylate; α-olefin compounds such as diisobutylene, isobutylene, linearene, ethylene, propylene and other olefins Compound; Examples of conjugated diene compounds include isoprene and butadiene.

Examples of the crosslinkable monomers include vinyl monomers such as divinylbenzene, 1,4-divinyloxybutane and divinylsulfone as vinyl compounds; and tetramethylolmethane tetra(meth)acrylate as (meth)acrylic compounds. , polytetramethylene glycol diacrylate, tetramethylolmethane tri(meth)acrylate, tetramethylolmethane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate ) acrylate, glycerol tri(meth)acrylate, glycerol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, 1,4-butanediol di Polyfunctional (meth)acrylate compounds such as (meth)acrylates; triallyl (iso)cyanurate, triallyl trimellitate, diallyl phthalate, diallyl acrylamide, diallyl ether as allyl compounds; tetramethoxysilane, tetraethoxysilane as silane compounds , methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, isopropyltrimethoxysilane, isobutyltrimethoxysilane, cyclohexyltrimethoxysilane, n-hexyltrimethoxysilane, n-octyltriethoxysilane, n-decyltrimethoxysilane, phenyltrimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diisopropyldimethoxysilane, trimethoxysilylstyrene, γ-(meth)acryloxypropyltrimethoxysilane, 1,3-divinyltetramethyldisilane Silane alkoxide compounds such as siloxane, methylphenyldimethoxysilane, diphenyldimethoxysilane; vinyltrimethoxysilane, vinyltriethoxysilane, dimethoxymethylvinylsilane, dimethoxyethylvinylsilane, diethoxymethylvinylsilane, diethoxyethylvinylsilane, ethylmethyldivinylsilane , methylvinyldimethoxysilane, ethylvinyldimethoxysilane, methylvinyldiethoxysilane, ethylvinyldiethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3- Polymerizable double bond-containing silane alkoxides such as methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, and 3-acryloxypropyltrimethoxysilane; cyclic siloxanes such as decamethylcyclopentasiloxane; one-end-modified silicones Modified (reactive) silicone oils such as oils, silicone oils at both ends and side chain silicone oils; carboxyl group-containing monomers such as (meth)acrylic acid, maleic acid and maleic anhydride;

The substrate particles can be obtained by polymerizing the polymerizable monomer having the ethylenically unsaturated group. The polymerization method is not particularly limited, and includes known methods such as radical polymerization, ionic polymerization, polycondensation (condensation polymerization, polycondensation), addition condensation, living polymerization, and living radical polymerization. Other polymerization methods include suspension polymerization in the presence of a radical polymerization initiator.

Examples of the inorganic material include silica, alumina, barium titanate, zirconia, carbon black, silicate glass, borosilicate glass, lead glass, soda lime glass, and alumina silicate glass.

The substrate particles may be organic-inorganic hybrid particles. The substrate particles may be core-shell particles. When the substrate particles are organic-inorganic hybrid particles, examples of the inorganic substance that is the material of the substrate particles include silica, alumina, barium titanate, zirconia, and carbon black. Preferably, the inorganic material is not metal. The substrate particles formed of silica are not particularly limited, but after hydrolyzing a silicon compound having two or more hydrolyzable alkoxysilyl groups to form crosslinked polymer particles, firing is performed as necessary. substrate particles obtained by carrying out. Examples of the organic-inorganic hybrid particles include organic-inorganic hybrid particles formed from a crosslinked alkoxysilyl polymer and an acrylic resin.

The organic-inorganic hybrid particles are preferably core-shell type organic-inorganic hybrid particles having a core and a shell disposed on the surface of the core. It is preferred that the core is an organic core. Preferably, the shell is an inorganic shell. The substrate particles are preferably organic-inorganic hybrid particles having an organic core and an inorganic shell disposed on the surface of the organic core.

Examples of the material for the organic core include the above-described organic materials.

Examples of the material for the inorganic shell include the inorganic substances mentioned above as the material for the substrate particles. The inorganic shell material is preferably silica. The inorganic shell is preferably formed by forming a metal alkoxide into a shell-like material on the surface of the core by a sol-gel method, and then firing the shell-like material. The metal alkoxide is preferably silane alkoxide. The inorganic shell is preferably made of silane alkoxide.

The particle size of the substrate particles can be selected in consideration of the particle size of the conductive particles. The particle size of the substrate particles is preferably 0.1 μm or more, more preferably 1 μm or more. The particle size of the substrate particles is preferably 1000 μm or less, more preferably 500 μm or less, even more preferably 300 μm or less, even more preferably 50 μm or less, and even more preferably 10 μm or less. When the particle diameter of the base material particles is at least the lower limit, the contact area between the conductive particles and the electrodes is increased, so that the reliability of conduction between the electrodes can be further improved, and the connection via the conductive particles. The connection resistance between the electrodes thus formed can be made even lower. Furthermore, when the conductive portion is formed on the surface of the substrate particles by electroless plating, the formation of agglomerated conductive particles can be made difficult. When the particle diameter of the substrate particles is equal to or less than the upper limit, the conductive particles are sufficiently compressed, the connection resistance between the electrodes can be further reduced, and the distance between the electrodes can be further reduced. can.

It is particularly preferable that the particle diameter of the substrate particles is 1 μm or more and 3 μm or less. When the particle size of the substrate particles is in the range of 1 μm or more and 3 μm or less, it becomes difficult to aggregate when forming the conductive portion on the surface of the substrate particles, and it becomes difficult to form aggregated conductive particles.

The particle size of the substrate particles is preferably an average particle size, more preferably a number average particle size. The particle diameter of the substrate particles is obtained by observing 50 arbitrary substrate particles with an electron microscope or an optical microscope, calculating the average value of the particle diameter of each substrate particle, or using a particle size distribution measuring device. is required. In observation with an electron microscope or an optical microscope, the particle size of each base particle is obtained as the particle size of the equivalent circle diameter. In observation with an electron microscope or an optical microscope, the average particle size of arbitrary 50 substrate particles in the equivalent circle diameter is approximately equal to the average particle size in the equivalent sphere diameter. In the particle size distribution analyzer, the particle size of one base particle is determined as the particle size in terms of equivalent sphere diameter. The average particle size of the substrate particles is preferably calculated using a particle size distribution analyzer. When measuring the particle size of the substrate particles of the conductive particles, it can be measured, for example, as follows.

The content of the conductive particles is added to "Technovit 4000" manufactured by Kulzer Co., Ltd. and dispersed to prepare an embedding resin for conductive particle inspection. Using an ion milling device (“IM4000” manufactured by Hitachi High-Technologies Corporation), a cross section of the conductive particles is cut out so as to pass through the vicinity of the center of the conductive particles dispersed in the embedding resin for inspection. Then, using a field emission scanning electron microscope (FE-SEM), set the image magnification to 25000 times, randomly select 50 conductive particles, and observe the base particles of each conductive particle. do. The particle diameter of the base material particles in each conductive particle is measured, and the arithmetic mean is taken as the particle size of the base material particles.

(Conductive part)
The conductive particles according to the present invention have a conductive portion. A conductive particle according to the present invention may comprise a substrate particle and a conductive portion arranged on the surface of the substrate particle. The conductive portion preferably contains a metal. The metal forming the conductive portion is not particularly limited.

Metals constituting the conductive portion include gold, silver, palladium, copper, platinum, zinc, iron, tin, lead, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, thallium, germanium, cadmium, Silicon, tungsten, molybdenum, alloys thereof, and the like are included. In addition, tin-doped indium oxide (ITO), solder, and the like are examples of the metal forming the conductive portion. Only one kind of the metal constituting the conductive portion may be used, or two or more kinds thereof may be used in combination.

From the viewpoint of more effectively lowering the connection resistance between the electrodes, the conductive portion preferably contains nickel, gold, palladium, silver, or copper, and more preferably contains nickel, gold, or palladium. It is particularly preferred to contain nickel.

The content of nickel in 100% by weight of the conductive portion containing nickel is preferably 10% by weight or more, more preferably 50% by weight or more, even more preferably 60% by weight or more, still more preferably 70% by weight or more, and particularly preferably is 90% by weight or more. The content of nickel in 100% by weight of the conductive portion containing nickel may be 97% by weight or more, may be 97.5% by weight or more, may be 98% by weight or more, and may be 100 % by weight.

Note that hydroxyl groups are often present on the surface of the conductive portion due to oxidation. In general, hydroxyl groups are present on the surface of the conductive portion made of nickel due to oxidation. An insulating substance can be placed on the surface of the conductive portion having such hydroxyl groups (the surface of the conductive particles) through chemical bonding.

The conductive portion may be formed of one layer. The conductive portion may be formed of a plurality of layers. That is, the conductive portion may have a laminated structure of two or more layers. When the conductive portion is formed of a plurality of layers, the metal constituting the outermost layer is preferably gold, nickel, palladium, copper, or an alloy containing tin and silver, and is preferably gold. more preferred. When the metal forming the outermost layer is one of these preferred metals, the connection resistance between the electrodes is even lower. Further, when the metal forming the outermost layer is gold, the corrosion resistance is further enhanced. The metal forming the outermost layer may be nickel.

The method of forming the conductive portion on the surface of the substrate particles is not particularly limited. Methods for forming the conductive portion include a method by electroless plating, a method by electroplating, a method by physical collision, a method by mechanochemical reaction, a method by physical vapor deposition or physical adsorption, and metal powder or metal powder. and a binder on the surface of the substrate particles. The method of forming the conductive portion is preferably electroless plating, electroplating, or a method using physical collision. Methods such as vacuum deposition, ion plating, and ion sputtering can be used as the method by physical vapor deposition. Also, as a method using physical collision, a sheeter composer (manufactured by Tokuju Kosakusho Co., Ltd.) or the like is used.

The thickness of the conductive portion is preferably 0.005 μm or more, more preferably 0.01 μm or more, and preferably 10 μm or less, more preferably 1 μm or less, and still more preferably 0.3 μm or less. The thickness of the conductive portion is the thickness of the entire conductive portion when the conductive portion has multiple layers. When the thickness of the conductive portion is at least the lower limit and at most the upper limit, sufficient conductivity is obtained, and the conductive particles are not too hard, and the conductive particles are sufficiently deformed when connecting the electrodes. can be made

When the conductive portion is formed of a plurality of layers, the thickness of the conductive portion in the outermost layer is preferably 0.001 μm or more, more preferably 0.01 μm or more, and preferably 0.5 μm or less, and more preferably. is 0.1 μm or less. When the thickness of the conductive portion of the outermost layer is equal to or more than the lower limit and equal to or less than the upper limit, the coating with the conductive portion of the outermost layer is uniform, the corrosion resistance is sufficiently high, and the connection resistance between the electrodes is sufficiently increased. can be lowered to Further, when the metal forming the outermost layer is gold, the thinner the outermost layer, the lower the cost.

The thickness of the conductive portion can be measured by observing the cross section of the conductive particles using, for example, a transmission electron microscope (TEM). Regarding the thickness of the conductive portion, it is preferable to calculate the average value of the thickness of the conductive portion at five locations as the thickness of the conductive portion of one conductive particle, and the average value of the thickness of the entire conductive portion. More preferably, it is calculated as the thickness of the conductive portion of the conductive particles. The thickness of the conductive portion is preferably obtained by calculating the average value of the thickness of the conductive portion of each conductive particle for 10 arbitrary conductive particles.

(Core substance and protrusion)
The conductive particles preferably have protrusions on the outer surface of the conductive portion. It is preferable that the protrusion is plural. An oxide film is often formed on the surface of the electrodes connected by the conductive particles. When conductive particles having projections on the surface of the conductive portion are used, the oxide film can be effectively removed by the projections by arranging the conductive particles between the electrodes and pressing them. Therefore, the electrodes and the conductive portions are more reliably brought into contact with each other, and the connection resistance between the electrodes is further reduced. Furthermore, when the conductive particles include an insulating substance, or when the conductive particles are dispersed in a binder resin and used as a conductive material, the protrusions of the conductive particles provide insulation between the conductive particles and the electrode. toxic substances or binder resins can be more effectively eliminated. Therefore, the connection resistance between the electrodes can be further reduced.

It is preferable that the conductive particles include a plurality of core substances that protrude the surface of the conductive portion within the conductive portion so as to form a plurality of projections within the conductive portion.

As a method of forming the projections, a method of forming a conductive portion by electroless plating after attaching a core substance to the surface of the substrate particle, and a method of forming a conductive portion by electroless plating on the surface of the substrate particle. After that, a core substance is adhered, and then a conductive portion is formed by electroless plating. Also, the core substance may not be used to form the protrusions.

Other methods of forming the projections include a method of adding a core substance during the process of forming the conductive portions on the surface of the substrate particles. Further, in order to form the projections, after forming the conductive portion on the base particles by electroless plating without using the core substance, plating is deposited on the surface of the conductive portion in the shape of a projection, and further electroless plating is performed. You may use the method of forming an electroconductive part by.

As a method of attaching the core substance to the surface of the substrate particles, the core substance is added to the dispersion liquid of the substrate particles, and the core substance is accumulated on the surface of the substrate particles by van der Waals force and adhered. method, and a method of adding the core substance to a container containing the substrate particles and attaching the core substance to the surfaces of the substrate particles by mechanical action such as rotation of the container. From the viewpoint of controlling the amount of the core substance to be deposited, the method of depositing the core substance on the surface of the substrate particles is preferably a method of accumulating and depositing the core substance on the surface of the substrate particles in the dispersion. preferable.

Materials constituting the core material include conductive materials and non-conductive materials. Examples of the conductive substance include conductive nonmetals such as metals, metal oxides, and graphite, and conductive polymers. Polyacetylene etc. are mentioned as said conductive polymer. Silica, alumina, zirconia, and the like are mentioned as the non-conductive substance. From the viewpoint of removing the oxide film more effectively, the core substance is preferably hard. From the viewpoint of more effectively lowering the connection resistance between the electrodes, the core substance is preferably metal.

The metal is not particularly limited. The above metals include metals such as gold, silver, copper, platinum, zinc, iron, lead, tin, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, germanium and cadmium, and tin-lead alloys, Alloys composed of two or more metals such as tin-copper alloy, tin-silver alloy, tin-lead-silver alloy, and tungsten carbide are included. From the viewpoint of more effectively lowering the connection resistance between the electrodes, the metal is preferably nickel, copper, silver or gold. The metal may be the same as or different from the metal forming the conductive portion (conductive layer).

The shape of the core substance is not particularly limited. The shape of the core substance is preferably massive. Examples of the core substance include particulate lumps, agglomerates in which a plurality of microparticles are aggregated, irregular-shaped lumps, and the like.

The particle size of the core substance is preferably 0.001 μm or more, more preferably 0.05 μm or more, and preferably 0.9 μm or less, more preferably 0.2 μm or less. When the particle size of the core substance is equal to or more than the lower limit and equal to or less than the upper limit, the connection resistance between the electrodes can be lowered more effectively.

The particle size of the core substance is preferably an average particle size, more preferably a number average particle size. The particle size of the core substance can be obtained by observing 50 arbitrary core substances with an electron microscope or an optical microscope and calculating the average value of the particle size of each core substance, or by using a particle size distribution analyzer. In observation with an electron microscope or an optical microscope, the particle size of the core substance per core substance is obtained as the particle size in the equivalent circle diameter. Observation with an electron microscope or an optical microscope WHEREIN: The average particle diameter in the circle equivalent diameter of arbitrary 50 core substances becomes substantially equal to the average particle diameter in the sphere equivalent diameter. In the particle size distribution analyzer, the particle size of one core substance is obtained as the particle size in terms of equivalent sphere diameter. The average particle size of the core substance is preferably calculated using a particle size distribution analyzer.

From the viewpoint of further lowering the initial connection resistance and further increasing the conduction reliability under high temperature and high humidity conditions, the surface area of the portion having the protrusions out of 100% of the total surface area of the outer surface of the conductive portion is preferably It is 25% or more, more preferably 30% or more, and still more preferably 50% or more. The surface area of the portion having the projections may be 95% or less, 90% or less, or 80% or less.

The number of protrusions per conductive particle is preferably 3 or more, more preferably 5 or more. The upper limit of the number of protrusions is not particularly limited. The upper limit of the number of protrusions can be appropriately selected in consideration of the particle size of the conductive particles. When the number of protrusions is equal to or greater than the lower limit, the connection resistance between the electrodes can be lowered more effectively.

The number of protrusions can be calculated by observing any conductive particles with an electron microscope or an optical microscope. The number of protrusions is preferably determined by observing 50 arbitrary conductive particles with an electron microscope or an optical microscope and calculating the average number of protrusions in each conductive particle.

The height of the protrusions is preferably 0.001 μm or more, more preferably 0.05 μm or more, and preferably 0.9 μm or less, more preferably 0.2 μm or less. When the height of the projection is equal to or higher than the lower limit and equal to or lower than the upper limit, the connection resistance between the electrodes can be lowered even more effectively.

The height of the protrusions can be calculated by observing the protrusions on any conductive particles with an electron microscope or an optical microscope. The height of the projections is preferably calculated by taking the average value of the heights of all the projections per conductive particle as the height of the projections of one conductive particle. The height of the projections is preferably obtained by calculating the average value of the heights of the projections of each conductive particle for 50 arbitrary conductive particles.

(insulating substance)
From the viewpoint of further enhancing the conductivity, the conductive particles do not have to be provided with an insulating substance arranged on the outer surface of the conductive portion. From the viewpoint of further improving insulation reliability, the conductive particles preferably include an insulating substance arranged on the outer surface of the conductive portion. In this case, if the conductive particles are used to connect the electrodes, short-circuiting between adjacent electrodes can be prevented more effectively. Specifically, when a plurality of conductive particles are brought into contact with each other, an insulating material exists between the plurality of electrodes, so short-circuiting between laterally adjacent electrodes can be prevented instead of between the electrodes above and below. When the electrodes are connected, the insulating material between the conductive portion of the conductive particles and the electrodes can be easily eliminated by pressing the conductive particles with two electrodes. Furthermore, in the case of the conductive particles having protrusions on the outer surface of the conductive portion, the insulating material between the conductive portion of the conductive particles and the electrode can be removed more easily.

Examples of the insulating substance include an insulating layer and insulating particles. The insulating substance is preferably insulating particles because the insulating substance can be removed more easily when the electrodes are crimped.

Examples of the material of the insulating substance include the above-described organic material, the above-described inorganic material, and the above-described inorganic substance as the material of the substrate particles. The material of the insulating substance is preferably the organic material described above.

Other materials for the insulating substance include polyolefin compounds, (meth)acrylate polymers, (meth)acrylate copolymers, block polymers, thermoplastic resins, crosslinked products of thermoplastic resins, thermosetting resins, and water-soluble Resin etc. are mentioned. Only one kind of the insulating substance may be used, or two or more kinds thereof may be used in combination.

Examples of the polyolefin compound include polyethylene, ethylene-vinyl acetate copolymer and ethylene-acrylate copolymer. Examples of the (meth)acrylate polymer include polymethyl (meth)acrylate, polydodecyl (meth)acrylate and polystearyl (meth)acrylate. Examples of the block polymer include polystyrene, styrene-acrylate copolymer, SB type styrene-butadiene block copolymer, SBS type styrene-butadiene block copolymer, and hydrogenated products thereof. Examples of the thermoplastic resin include vinyl polymers and vinyl copolymers. Examples of the thermosetting resin include epoxy resin, phenol resin and melamine resin. Examples of the cross-linked thermoplastic resin include introduction of polyethylene glycol methacrylate, alkoxylated trimethylolpropane methacrylate, alkoxylated pentaerythritol methacrylate, and the like. Examples of the water-soluble resin include polyvinyl alcohol, polyacrylic acid, polyacrylamide, polyvinylpyrrolidone, polyethylene oxide and methyl cellulose. A chain transfer agent may also be used to adjust the degree of polymerization. Examples of chain transfer agents include thiols and carbon tetrachloride.

Methods for disposing the insulating material on the surface of the conductive portion include chemical methods and physical or mechanical methods. Examples of the chemical method include an interfacial polymerization method, a suspension polymerization method in the presence of particles, an emulsion polymerization method, and the like. Examples of the physical or mechanical methods include spray drying, hybridization, electrostatic adhesion, atomization, dipping and vacuum deposition. From the viewpoint of more effectively improving the insulation reliability and conduction reliability when the electrodes are electrically connected, the method of disposing the insulating substance on the surface of the conductive portion is a physical method. Preferably.

An outer surface of the conductive portion and an outer surface of the insulating substance may each be coated with a compound having a reactive functional group. The outer surface of the conductive portion and the outer surface of the insulating material may not be directly chemically bonded, but may be indirectly chemically bonded by a compound having a reactive functional group. After introducing carboxyl groups to the outer surface of the conductive portion, the carboxyl groups may be chemically bonded to functional groups on the outer surface of the insulating material via a polymer electrolyte such as polyethyleneimine.

When the insulating substance is insulating particles, the particle size of the insulating particles can be appropriately selected depending on the particle size of the conductive particles, the application of the conductive particles, and the like. The particle diameter of the insulating particles is preferably 10 nm or more, more preferably 100 nm or more, still more preferably 300 nm or more, particularly preferably 500 nm or more, preferably 4000 nm or less, more preferably 2000 nm or less, and further preferably 1500 nm or less. , and particularly preferably 1000 nm or less. If the particle diameter of the insulating particles is at least the above lower limit, it becomes difficult for the conductive portions of the plurality of conductive particles to come into contact with each other when the conductive particles are dispersed in the binder resin. When the particle size of the insulating particles is equal to or less than the above upper limit, it becomes unnecessary to increase the pressure too much in order to eliminate the insulating particles between the electrodes and the conductive particles when connecting the electrodes. no longer need to be heated to

The particle size of the insulating particles is preferably an average particle size, more preferably a number average particle size. The particle diameter of the insulating particles is obtained by observing 50 arbitrary insulating particles with an electron microscope or an optical microscope, calculating the average particle size of each insulating particle, or using a particle size distribution measuring device. Desired. In observation with an electron microscope or an optical microscope, the particle diameter of each insulating particle is obtained as the particle diameter in equivalent circle diameter. In observation with an electron microscope or an optical microscope, the average particle size of arbitrary 50 insulating particles in equivalent circle diameter is almost equal to the average particle size in equivalent sphere diameter. In the particle size distribution analyzer, the particle diameter of each insulating particle is obtained as the particle diameter in terms of equivalent sphere diameter. The average particle size of the insulating particles is preferably calculated using a particle size distribution analyzer. When measuring the particle size of the insulating particles in the conductive particles, the measurement can be performed, for example, as follows.

Conductive particles are added to "Technovit 4000" manufactured by Kulzer Co., Ltd. so that the content is 30% by weight, and dispersed to prepare an embedding resin for conducting particle inspection. Using an ion milling device (“IM4000” manufactured by Hitachi High-Technologies Corporation), a cross section of the conductive particles is cut out so as to pass through the vicinity of the center of the dispersed conductive particles in the embedding resin for inspection. Then, using a field emission scanning electron microscope (FE-SEM), set the image magnification to 50,000 times, randomly select 50 conductive particles, and observe the insulating particles of each conductive particle. do. The particle diameter of the insulating particles in each conductive particle is measured, and the arithmetic mean is taken as the particle diameter of the insulating particles.

The ratio of the particle size of the conductive particles to the particle size of the insulating particles (particle size of conductive particles/particle size of insulating particles) is preferably 4 or more, more preferably 8 or more, preferably 200 or less, more preferably 100 or less. When the ratio (particle diameter of conductive particles/particle diameter of insulating particles) is equal to or greater than the lower limit and equal to or lower than the upper limit, insulation reliability and conduction reliability are improved when the electrodes are electrically connected. can be enhanced more effectively.

(Conductive material)
The conductive material according to the present invention contains the conductive particles described above and a binder resin. The conductive particles are preferably dispersed in a binder resin for use, and preferably dispersed in a binder resin for use as a conductive material. The conductive material is preferably an anisotropic conductive material. The conductive material is preferably used for electrical connection between electrodes. The conductive material is preferably a conductive material for circuit connection. Since the above-described conductive particles are used in the conductive material, the connection resistance between the electrodes can be more effectively reduced, and the occurrence of agglomeration of the conductive particles can be more effectively suppressed. be able to. Since the conductive particles described above are used in the conductive material, the reliability of insulation between electrodes can be further effectively improved.

The binder resin is not particularly limited. A known insulating resin is used as the binder resin. The binder resin preferably contains a thermoplastic component (thermoplastic compound) or a curable component, and more preferably contains a curable component. Examples of the curable component include photocurable components and thermosetting components. The photocurable component preferably contains a photocurable compound and a photopolymerization initiator. The thermosetting component preferably contains a thermosetting compound and a thermosetting agent.

Examples of the binder resin include vinyl resins, thermoplastic resins, curable resins, thermoplastic block copolymers, elastomers, and the like. Only one kind of the binder resin may be used, or two or more kinds thereof may be used in combination.

Examples of the vinyl resin include vinyl acetate resin, acrylic resin and styrene resin. Examples of the thermoplastic resins include polyolefin resins, ethylene-vinyl acetate copolymers and polyamide resins. Examples of the curable resin include epoxy resin, urethane resin, polyimide resin and unsaturated polyester resin. The curable resin may be a room temperature curable resin, a thermosetting resin, a photocurable resin, or a moisture curable resin. The curable resin may be used in combination with a curing agent. Examples of the thermoplastic block copolymers include styrene-butadiene-styrene block copolymers, styrene-isoprene-styrene block copolymers, hydrogenated products of styrene-butadiene-styrene block copolymers, and styrene-isoprene-styrene Examples thereof include hydrogenated products of block copolymers. Examples of the elastomer include styrene-butadiene copolymer rubber and acrylonitrile-styrene block copolymer rubber.

In addition to the conductive particles and the binder resin, the conductive material includes, for example, a filler, an extender, a softener, a plasticizer, a polymerization catalyst, a curing catalyst, a coloring agent, an antioxidant, a heat stabilizer, and a light stabilizer. It may contain various additives such as agents, UV absorbers, lubricants, antistatic agents and flame retardants.

A method for dispersing the conductive particles in the binder resin may be a conventionally known dispersing method, and is not particularly limited. Examples of the method for dispersing the conductive particles in the binder resin include the following methods. A method of adding the conductive particles to the binder resin and then kneading and dispersing the mixture with a planetary mixer or the like. A method in which the conductive particles are uniformly dispersed in water or an organic solvent using a homogenizer or the like, then added to the binder resin, kneaded with a planetary mixer or the like, and dispersed. A method of diluting the binder resin with water, an organic solvent, or the like, adding the conductive particles, and kneading and dispersing the mixture with a planetary mixer or the like.

The viscosity (η25) of the conductive material at 25° C. is preferably 30 Pa·s or more, more preferably 50 Pa·s or more, and preferably 400 Pa·s or less, more preferably 300 Pa·s or less. When the viscosity of the conductive material at 25 ° C. is at least the lower limit and at most the upper limit, the insulation reliability between the electrodes can be more effectively improved, and the conduction reliability between the electrodes can be more effectively improved. can be increased to The viscosity (η25) can be appropriately adjusted depending on the types and amounts of ingredients to be blended.

The viscosity (η25) can be measured at 25° C. and 5 rpm using, for example, an E-type viscometer ("TVE22L" manufactured by Toki Sangyo Co., Ltd.).

The conductive material according to the present invention can be used as conductive paste, conductive film, and the like. When the conductive material according to the present invention is a conductive film, a film containing no conductive particles may be laminated on a conductive film containing conductive particles. The conductive paste is preferably an anisotropic conductive paste. The conductive film is preferably an anisotropic conductive film.

The content of the binder resin in 100% by weight of the conductive material is preferably 10% by weight or more, more preferably 30% by weight or more, still more preferably 50% by weight or more, and particularly preferably 70% by weight or more. is 99.99% by weight or less, more preferably 99.9% by weight or less. When the content of the binder resin is the lower limit or more and the upper limit or less, the conductive particles are efficiently arranged between the electrodes, and the connection reliability of the connection target members connected by the conductive material is further improved. can be done.

The content of the conductive particles in 100% by weight of the conductive material is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, and preferably 80% by weight or less, more preferably 60% by weight. %, more preferably 40% by weight or less, particularly preferably 20% by weight or less, and most preferably 10% by weight or less. When the content of the conductive particles is equal to or more than the lower limit and equal to or less than the upper limit, the connection resistance between the electrodes can be lowered even more effectively. When the content of the conductive particles is equal to or more than the lower limit and equal to or less than the upper limit, reliability of electrical connection and reliability of insulation between electrodes can be further enhanced.

(connection structure)
A connection structure according to the present invention includes: a first member to be connected having a first electrode on its surface; a second member to be connected having a second electrode on its surface; and a connecting portion connecting to the second connection target member. In the connected structure according to the present invention, the material of the connecting portion is the conductive particles described above, or a conductive material containing the conductive particles and a binder resin. In the connection structure according to the present invention, the first electrode and the second electrode are electrically connected by the conductive particles.

The connection structure includes a step of disposing the conductive particles or the conductive material between the first member to be connected and the second member to be connected, and a step of electrically connecting by thermocompression bonding. can be obtained through When the conductive particles contain the insulating substance, it is preferable that the insulating substance is detached from the conductive particles during the thermocompression bonding.

When the conductive particles are used alone, the connecting portion itself is the conductive particles. That is, the first member to be connected and the second member to be connected are connected by the conductive particles. The conductive material used to obtain the connection structure is preferably an anisotropic conductive material.

FIG. 5 is a front cross-sectional view schematically showing a connection structure using conductive particles according to the first embodiment of the present invention.

A connection structure 51 shown in FIG. 5 includes a first connection target member 52, a second connection target member 53, and a connection portion 54 connecting the first and second connection target members 52 and 53. Prepare. The connecting portion 54 is formed by curing a conductive material containing the conductive particles 1 . In addition, in FIG. 5, the conductive particles 1 are schematically shown for convenience of illustration. Instead of the conductive particles 1, other conductive particles such as the conductive particles 11 and 21 may be used.

The first connection target member 52 has a plurality of first electrodes 52a on its surface (upper surface). The second connection target member 53 has a plurality of second electrodes 53a on its surface (lower surface). A first electrode 52 a and a second electrode 53 a are electrically connected by one or more conductive particles 1 . Therefore, the first and second connection object members 52 and 53 are electrically connected by the conductive particles 1 .

The manufacturing method of the connection structure is not particularly limited. As an example of a method for manufacturing a connected structure, the conductive material is arranged between a first member to be connected and a second member to be connected to obtain a laminate, and then the laminate is heated and pressurized. methods and the like. The pressure of the thermocompression bonding is preferably 40 MPa or higher, more preferably 60 MPa or higher, and preferably 90 MPa or lower, more preferably 70 MPa or lower. The heating temperature for the thermocompression bonding is preferably 80° C. or higher, more preferably 100° C. or higher, and preferably 140° C. or lower, more preferably 120° C. or lower. When the pressure and temperature of the thermocompression bonding are equal to or higher than the lower limit and equal to or lower than the upper limit, reliability of electrical connection and reliability of insulation between electrodes can be further enhanced. Moreover, when the conductive particles have the insulating particles, the insulating particles can be easily detached from the surfaces of the conductive particles at the time of conductive connection.

When the conductive particles have the insulating particles, when the laminate is heated and pressurized, the conductive particles are present between the first electrode and the second electrode. It is possible to eliminate the above-mentioned insulating particles that are present. For example, during the heating and pressurization, the insulating particles present between the conductive particles and the first electrode and the second electrode are separated from the surfaces of the conductive particles. Detach easily. During the heating and pressing, some of the insulating particles may detach from the surfaces of the conductive particles, partially exposing the surfaces of the conductive portions. The exposed portion of the conductive portion is in contact with the first electrode and the second electrode, thereby electrically connecting the first electrode and the second electrode via the conductive particles. can do.

The first member to be connected and the second member to be connected are not particularly limited. Specifically, the first connection target member and the second connection target member include electronic components such as semiconductor chips, semiconductor packages, LED chips, LED packages, capacitors and diodes, as well as resin films, printed circuit boards, flexible Examples include electronic components such as circuit boards such as printed boards, flexible flat cables, rigid flexible boards, glass epoxy boards and glass boards. The first member to be connected and the second member to be connected are preferably electronic components.

The electrodes provided on the connection object members include metal electrodes such as gold electrodes, nickel electrodes, tin electrodes, aluminum electrodes, copper electrodes, molybdenum electrodes, silver electrodes, SUS electrodes, and tungsten electrodes. When the member to be connected is a flexible printed circuit board, the electrode is preferably a gold electrode, a nickel electrode, a tin electrode, a silver electrode or a copper electrode. When the member to be connected is a glass substrate, the electrode is preferably an aluminum electrode, a copper electrode, a molybdenum electrode, a silver electrode, or a tungsten electrode. When the electrode is an aluminum electrode, it may be an electrode made of only aluminum, or an electrode in which an aluminum layer is laminated on the surface of a metal oxide layer. Examples of materials for the metal oxide layer include indium oxide doped with a trivalent metal element and zinc oxide doped with a trivalent metal element. Examples of the trivalent metal elements include Sn, Al and Ga.

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples. The invention is not limited only to the following examples.

In order to introduce the following organosilicon functional groups into the resulting conductive particles, the following organosilicon compounds were used.

A: Organosilicon compound for introducing an organosilicon functional group having an alkyl group having 10 carbon atoms Decyltrimethoxysilane (organosilicon compound A)
B: Organosilicon compound for introducing an organosilicon functional group having a benzotriazole group Benzotriazolemethyltrimethoxysilane (a compound in which a benzotriazole group is added to the methyl group of methyltrimethoxysilane) (organosilicon compound B)
C: an organosilicon compound for introducing an organosilicon functional group having a (meth)acryloyl group 3-methacryloxypropyltrimethoxysilane (organosilicon compound C)
D: Organosilicon compound for introducing organosilicon functional groups having epoxy groups 3-glycidoxypropyltrimethoxysilane (organosilicon compound D)

The following compounds were used in order to surface-treat the conductive portions of the obtained conductive particles.

Phosphate compound: phosphate monohexyl ester Benzotriazole compound: 1,2,3-benzotriazole Thiazole compound: 2-mercaptobenzothiazole

(Example 1)
(1) Preparation of Conductive Particles As base particles A, divinylbenzene copolymer resin particles (base particles A, “Micropearl SP-203” manufactured by Sekisui Chemical Co., Ltd., particle size 3 μm) were prepared. After dispersing 10 parts by weight of the base particles A in 100 parts by weight of an alkaline solution containing 5% by weight of a palladium catalyst solution using an ultrasonic disperser, the solution was filtered to obtain the base particles A. . Next, the substrate particles A were added to 100 parts by weight of a 1% by weight solution of dimethylamine borane to activate the surfaces of the substrate particles A. After thoroughly washing the surface-activated substrate particles A with water, they were added to 500 parts by weight of distilled water and dispersed to obtain a dispersion liquid.

Next, 1 part by weight of alumina particle slurry (average particle size: 150 nm) was added to the above dispersion over 3 minutes to obtain a suspension containing base particles A to which the core substance was attached.

A nickel plating solution (pH 8.5) containing 0.14 mol/L nickel sulfate, 0.46 mol/L dimethylamine borane, and 0.2 mol/L sodium citrate was prepared as a nickel plating solution.

While stirring the obtained suspension at 60° C., the nickel plating solution was added dropwise to the suspension for 10 minutes at a drop rate of 30 mL/min. After that, it was dropped for 40 minutes at a dropping rate of 10 mL/min, and then dropped for 80 minutes at a dropping rate of 4 mL/min. Nickel-boron alloy plating was performed.

After that, by filtering the suspension, the particles are taken out, washed with water, and dried to form the first conductive portion (conductive layer containing nickel, thickness 0.1 μm) on the surface of the substrate particles A. Placed particles were obtained.

5 parts by weight of the obtained particles were dispersed in 100 parts by weight of ethanol to obtain a particle dispersion.

To 50 parts by weight of ethanol, 10 parts by weight of water, 0.8 parts by weight of acetic acid, and 1.5 parts by weight of organosilicon compound A were added, and the mixture was stirred at room temperature for 200 minutes to obtain solution A. To 50 parts by weight of ethanol, 10 parts by weight of water, 0.8 parts by weight of acetic acid, and 1.5 parts by weight of organosilicon compound D were added, and the mixture was stirred at room temperature for 200 minutes to obtain solution D.

The solution A and the solution D were added to the particle dispersion, heated to 50° C. and stirred to obtain conductive particles whose surfaces were modified with the organosilicon compounds A and D.

(2) Preparation of conductive material 60 parts by weight of phenoxy resin (“YP-50” manufactured by Nippon Steel Chemical & Materials Co., Ltd.), 40 parts by weight of epoxy resin (“jER828” manufactured by Mitsubishi Chemical Corporation), and a cationic curing agent (three "SI-60L" manufactured by Shin Kagaku Kogyo Co., Ltd.) was mixed with 2 parts by weight to obtain an insulating adhesive. The obtained conductive particles were added to the insulating adhesive so that the content thereof in 100% by weight of the conductive film to be obtained was 5% by weight to obtain a first mixture. After that, methyl ethyl ketone was added to the first mixture so that the solid content was 50% by weight, and the mixture was stirred at 2000 rpm for 5 minutes using a planetary stirrer to obtain a second mixture. The obtained second mixture was applied onto the release-treated polyethylene terephthalate, and the solvent was dried to obtain an anisotropic conductive film having a thickness of 20 μm.

(3) Production of Connection Structure A polyimide substrate (flexible printed circuit board) having an Al--Ti 4% electrode pattern (Al--Ti 4% electrode thickness of 1 μm) with an L/S of 20 μm/20 μm on its upper surface was prepared. Also, a semiconductor chip having a gold electrode pattern (gold electrode thickness 20 μm) with L/S of 20 μm/20 μm on the lower surface was prepared. After attaching the prepared anisotropic conductive film to the upper surface of the polyimide substrate at 80° C. and 0.98 MPa (10 kgf/cm 2 ), the separator was peeled off, and the bumps of the chip with gold bumps and the Al—Ti circuit were bonded. Aligned. Next, a pressure heating head was placed on the upper surface of the semiconductor chip, and the anisotropic conductive material layer was cured at 180° C. while applying a low pressure of 1 MPa calculated from the pressure bonding area to obtain a connection structure.

(Example 2)
As the substrate particles A, divinylbenzene copolymer resin particles (substrate particles A, “Micropearl SP-203” manufactured by Sekisui Chemical Co., Ltd., particle size 3 μm) were prepared. After dispersing 10 parts by weight of the base particles A in 100 parts by weight of an alkaline solution containing 5% by weight of a palladium catalyst solution using an ultrasonic disperser, the solution was filtered to obtain the base particles A. . Next, the substrate particles A were added to 100 parts by weight of a 1% by weight solution of dimethylamine borane to activate the surfaces of the substrate particles A. The surface-activated substrate particles A were sufficiently washed with water and then dispersed in 500 parts by weight of distilled water to obtain a suspension containing the substrate particles A to which no core substance was adhered. Conductive particles were obtained in the same manner as in Example 1, except that the obtained suspension was used.

A conductive film and a connection structure were obtained in the same manner as in Example 1, except that the obtained conductive particles were used.

(Example 3)
Conductive particles were obtained in the same manner as in Example 1, except that a nickel particle slurry (average particle size: 150 nm) was used instead of the alumina particle slurry (average particle size: 150 nm).

A conductive film and a connection structure were obtained in the same manner as in Example 1, except that the obtained conductive particles were used.

(Example 4)
Conductive particles were obtained in the same manner as in Example 1, except that a titania particle slurry (average particle size: 150 nm) was used instead of the alumina particle slurry (average particle size: 150 nm).

A conductive film and a connection structure were obtained in the same manner as in Example 1, except that the obtained conductive particles were used.

(Example 5)
Conductive particles were obtained in the same manner as in Example 1, except that substrate particles B, which differed from substrate particles A only in particle diameter and had a particle diameter of 1.5 μm, were used.

A conductive film and a connection structure were obtained in the same manner as in Example 1, except that the obtained conductive particles were used.

(Example 6)
Conductive particles were obtained in the same manner as in Example 1, except that substrate particles C, which differed from substrate particles A only in particle diameter and had a particle diameter of 20 μm, were used.

A conductive film and a connection structure were obtained in the same manner as in Example 1, except that the obtained conductive particles were used.

(Example 7)
The following monomer composition is put into a 1000 mL separable flask equipped with a 4-neck separable cover, a stirring blade, a three-way cock, a cooling tube and a temperature probe, and the solid content of the monomer composition becomes 5% by weight. After weighing the ion-exchanged water as described above, the mixture was stirred at 200 rpm and polymerized at 70° C. for 24 hours in a nitrogen atmosphere. The monomer composition contains 100 mmol of methyl methacrylate, 1 mmol of N,N,N-trimethyl-N-2-methacryloyloxyethylammonium chloride, and 1 mmol of 2,2′-azobis(2-amidinopropane) dihydrochloride. include. After completion of the reaction, the mixture was lyophilized to obtain insulating particles having an ammonium group on the surface, an average particle size of 220 nm and a CV value of 10%.

The insulating particles were dispersed in ion-exchanged water under ultrasonic irradiation to obtain a 10% by weight aqueous dispersion of the insulating particles.

10 g of the conductive particles obtained in Example 1 were dispersed in 500 mL of ion-exchanged water, 4 g of an aqueous dispersion of insulating particles was added, and the mixture was stirred at room temperature for 6 hours. After filtration through a 3 μm mesh filter, the particles were further washed with methanol and dried to obtain conductive particles to which insulating particles adhered (conductive particles with insulating particles).

Observation with a scanning electron microscope (SEM) revealed that only one coating layer of insulating particles was formed on the surfaces of the conductive particles. When the coverage area of the insulating particles (that is, the projected area of the particle diameter of the insulating particles) with respect to the area of 2.5 μm from the center of the conductive particles was calculated by image analysis, the coverage was 40%.

A conductive film and a connection structure were obtained in the same manner as in Example 1, except that the obtained conductive particles (conductive particles with insulating particles) were used.

(Example 8)
Into a 500 mL reaction vessel equipped with a stirrer and thermometer was placed 300 g of 0.13 wt % aqueous ammonia solution. Next, 1.9 g of methyltrimethoxysilane, 12.7 g of vinyltrimethoxysilane, and 0.4 g of silicone alkoxy oligomer A ("KR-517" manufactured by Shin-Etsu Chemical Co., Ltd.) were added to the aqueous ammonia solution in the reaction vessel. was added slowly. After allowing the hydrolysis and condensation reactions to proceed with stirring, 1.6 mL of a 25% by weight aqueous ammonia solution was added, the particles were isolated from the aqueous ammonia solution, and the obtained particles were treated under an oxygen partial pressure of 10 ⁻¹⁰ atm. Firing was performed at 380° C. (firing temperature) for 2 hours (firing time) to obtain organic-inorganic hybrid particles (substrate particles D). The particle diameter of the obtained organic-inorganic hybrid particles (substrate particles D) was 3 μm.

Conductive particles were obtained in the same manner as in Example 1, except that the substrate particles D were used instead of the substrate particles A.

A conductive film and a connection structure were obtained in the same manner as in Example 1, except that the obtained conductive particles were used.

(Example 9)
A suspension similar to that of Example 1 was prepared.

A nickel plating solution (pH 8.5) containing 0.14 mol/L of nickel sulfate, 0.46 mol/L of dimethylamine borane, and 0.2 mol/L of sodium citrate was prepared as the nickel plating solution (1).

As the nickel plating solution (2), a nickel plating solution (pH 8.0) containing 0.14 mol/L of nickel sulfate and 0.60 mol/L of titanium (III) chloride was prepared.

While the obtained suspension was stirred at 60° C., the nickel plating solution (1) was added dropwise to the suspension for 5 minutes at a drop rate of 6 mL/min. After that, it is dropped for 20 minutes at a dropping rate of 2 mL/min, and then dropped for 40 minutes at a dropping rate of 0.8 mL/min, thereby controlling the content of boron incorporated into the plating film. Electroless nickel-boron alloy plating was performed on the surface of the substrate particles A (thickness: 0.05 μm). Subsequently, the solution temperature was set to 70° C., and the nickel plating solution (2) was gradually added dropwise to carry out electroless nickel plating to obtain a suspension (2).

After that, by filtering the suspension (2), the particles are taken out, washed with water, and dried to form a nickel-boron alloy conductive layer (thickness: 0.05 μm) on the surface of the substrate particle A and a pure layer. Particles in which the first conductive portion (main metal: nickel, thickness 0.1 μm) including a nickel conductive layer (thickness 0.05 μm) were arranged were obtained.

Conductive particles were obtained in the same manner as in Example 1, except that the obtained particles were used.

A conductive film and a connection structure were obtained in the same manner as in Example 1, except that the obtained conductive particles were used.

(Example 10)
A particle dispersion similar to that of Example 1 was prepared.

To 50 parts by weight of ethanol, 10 parts by weight of water, 0.8 parts by weight of acetic acid, and 1.5 parts by weight of organosilicon compound A were added, and the mixture was stirred at room temperature for 200 minutes to obtain solution A. To 50 parts by weight of ethanol, 10 parts by weight of water, 0.8 parts by weight of acetic acid, and 1.5 parts by weight of organosilicon compound B were added, and the mixture was stirred at room temperature for 200 minutes to obtain solution B. To 50 parts by weight of ethanol, 10 parts by weight of water, 0.8 parts by weight of acetic acid, and 1.5 parts by weight of organosilicon compound D were added, and the mixture was stirred at room temperature for 200 minutes to obtain solution D.

The solution A, the solution B, and the solution D are added to the particle dispersion, heated to 50° C., and stirred to form conductive particles whose surfaces are modified with the organosilicon compounds A, B, and D. Obtained.

A conductive film and a connection structure were obtained in the same manner as in Example 1, except that the obtained conductive particles were used.

(Example 11)
A particle dispersion similar to that of Example 1 was prepared.

To 50 parts by weight of ethanol, 10 parts by weight of water, 0.8 parts by weight of acetic acid, and 1.5 parts by weight of organosilicon compound A were added, and the mixture was stirred at room temperature for 200 minutes to obtain solution A. To 50 parts by weight of ethanol, 10 parts by weight of water, 0.8 parts by weight of acetic acid, and 1.5 parts by weight of organosilicon compound C were added, and the mixture was stirred at room temperature for 200 minutes to obtain solution C. To 50 parts by weight of ethanol, 10 parts by weight of water, 0.8 parts by weight of acetic acid, and 1.5 parts by weight of organosilicon compound D were added, and the mixture was stirred at room temperature for 200 minutes to obtain solution D.

The solution A, the solution C, and the solution D are added to the particle dispersion, heated to 50° C. and stirred to form conductive particles whose surfaces are modified with the organosilicon compounds A, C, and D. Obtained.

Phenoxy resin (“PKHC” manufactured by Union Carbide Co., Ltd.), acrylic rubber (40 parts by weight of butyl acrylate, 30 parts by weight of ethyl acrylate, 30 parts by weight of acrylonitrile, and 3 parts by weight of glycidyl methacrylate, copolymer, weight average molecular weight: 850,000 ) and were prepared. 30 g of the phenoxy resin and 15 g of the acrylic rubber were dissolved in 20 g of ethyl acetate to obtain a solution having a total concentration of 30% by weight of the phenoxy resin and the acrylic rubber. To this solution, 30 g of a liquid epoxy resin containing a microcapsule-type latent curing agent (epoxy equivalent: 185, "Novacure HX-3941" manufactured by Asahi Kasei Epoxy Co., Ltd.) was added and stirred to prepare an insulating adhesive solution. The obtained conductive particles were added to the insulating adhesive solution so that the content thereof in 100% by weight of the resulting conductive film was 5% by weight to obtain a first mixture. After that, methyl ethyl ketone was added to the first mixture so that the solid content was 50%, and the mixture was stirred at 2000 rpm for 5 minutes using a planetary stirrer to obtain a second mixture. The obtained second mixture was applied onto the release-treated polyethylene terephthalate, and the solvent was dried to obtain an anisotropic conductive film having a thickness of 20 μm.

A connection structure was obtained in the same manner as in Example 1, except that the obtained conductive film was used.

(Example 12)
A particle dispersion similar to that of Example 1 was prepared.

To 50 parts by weight of ethanol, 10 parts by weight of water, 0.8 parts by weight of acetic acid, and 1.5 parts by weight of organosilicon compound A were added, and the mixture was stirred at room temperature for 200 minutes to obtain solution A. To 50 parts by weight of ethanol, 10 parts by weight of water, 0.8 parts by weight of acetic acid, and 1.5 parts by weight of organosilicon compound B were added, and the mixture was stirred at room temperature for 200 minutes to obtain solution B. To 50 parts by weight of ethanol, 10 parts by weight of water, 0.8 parts by weight of acetic acid, and 1.5 parts by weight of organosilicon compound C were added, and the mixture was stirred at room temperature for 200 minutes to obtain solution C. To 50 parts by weight of ethanol, 10 parts by weight of water, 0.8 parts by weight of acetic acid, and 1.5 parts by weight of organosilicon compound D were added, and the mixture was stirred at room temperature for 200 minutes to obtain solution D.

The above solution A, the above solution B, the above solution C, and the above solution D are added to the above particle dispersion, heated to 50° C. and stirred to modify the surface of the particles with the organosilicon compounds A and B and C and D. obtained conductive particles.

A conductive film and a connection structure were obtained in the same manner as in Example 1, except that the obtained conductive particles were used.

Phenoxy resin (“PKHC” manufactured by Union Carbide Co., Ltd.), acrylic rubber (40 parts by weight of butyl acrylate, 30 parts by weight of ethyl acrylate, 30 parts by weight of acrylonitrile, and 3 parts by weight of glycidyl methacrylate, copolymer, weight average molecular weight: 850,000 ) and were prepared. 30 g of the phenoxy resin and 15 g of the acrylic rubber were dissolved in 20 g of ethyl acetate to obtain a solution having a total concentration of 30% by weight of the phenoxy resin and the acrylic rubber. To this solution, 30 g of a liquid epoxy resin containing a microcapsule-type latent curing agent (epoxy equivalent: 185, "Novacure HX-3941" manufactured by Asahi Kasei Epoxy Co., Ltd.) was added and stirred to prepare an insulating adhesive solution. The obtained conductive particles were added to the insulating adhesive solution so that the content thereof in 100% by weight of the resulting conductive film was 5% by weight to obtain a first mixture. After that, methyl ethyl ketone was added to the first mixture so that the solid content was 50%, and the mixture was stirred at 2000 rpm for 5 minutes using a planetary stirrer to obtain a second mixture. The obtained second mixture was applied onto the release-treated polyethylene terephthalate, and the solvent was dried to obtain an anisotropic conductive film having a thickness of 20 μm.

A connection structure was obtained in the same manner as in Example 1, except that the obtained conductive film was used.

(Example 13)
A particle dispersion similar to that of Example 1 was prepared.

To 50 parts by weight of ethanol, 10 parts by weight of water, 0.8 parts by weight of acetic acid, and 1.5 parts by weight of organosilicon compound B were added, and the mixture was stirred at room temperature for 200 minutes to obtain solution B. To 50 parts by weight of ethanol, 10 parts by weight of water, 0.8 parts by weight of acetic acid, and 1.5 parts by weight of organosilicon compound D were added, and the mixture was stirred at room temperature for 200 minutes to obtain solution D.

The solution B and the solution D were added to the particle dispersion, heated to 50° C. and stirred to obtain conductive particles whose surfaces were modified with the organosilicon compounds B and D.

A conductive film and a connection structure were obtained in the same manner as in Example 1, except that the obtained conductive particles were used.

(Example 14)
Particles similar to those in Example 1, that is, particles in which the first conductive part (conductive layer containing nickel, thickness 0.1 μm) is arranged on the surface of the substrate particle A were prepared.

10 parts by weight of the obtained particles were dispersed in 500 parts by weight of ion-exchanged water using an ultrasonic processor to obtain a suspension.

A palladium plating solution (pH 10.0) containing 0.02 mol/L palladium sulfate, 0.04 mol/L ethylenediamine as a complexing agent, 0.06 mol/L ammonium formate as a reducing agent, and a crystal modifier was prepared.

While stirring the resulting suspension at 50° C., the palladium plating solution was gradually added to perform electroless palladium plating to form a second conductive portion. Electroless palladium plating was terminated when the thickness of the second conductive portion reached 20 nm. Conductive particles (particle size: 3.24 μm) were obtained in which the second conductive portion (palladium layer, thickness: 0.02 μm) was arranged on the surface of the first conductive portion.

A conductive film and a connection structure were obtained in the same manner as in Example 1, except that the obtained conductive particles were used.

(Example 15)
Conductive particles were obtained in the same manner as in Example 14, except that electroless gold plating was applied instead of electroless palladium plating when forming the second conductive portion.

A conductive film and a connection structure were obtained in the same manner as in Example 1, except that the obtained conductive particles were used.

(Example 16)
Conductive particles were obtained in the same manner as in Example 14, except that electroless silver plating was applied instead of electroless palladium plating when forming the second conductive portion.

A conductive film and a connection structure were obtained in the same manner as in Example 1, except that the obtained conductive particles were used.

(Example 17)
Conductive particles were obtained in the same manner as in Example 14, except that electroless ruthenium plating was applied instead of electroless palladium plating when forming the second conductive portion.

A conductive film and a connection structure were obtained in the same manner as in Example 1, except that the obtained conductive particles were used.

(Example 18)
A suspension similar to that of Example 1 was prepared.

A nickel plating solution (pH 8.5) containing 0.14 mol/L of nickel sulfate, 0.46 mol/L of dimethylamine borane, and 0.2 mol/L of sodium citrate was prepared as the nickel plating solution (1).

As the nickel plating solution (2), a nickel plating solution (pH 8.0) containing 0.14 mol/L of nickel sulfate and 0.60 mol/L of titanium (III) chloride was prepared.

While the resulting suspension was stirred at 60° C., the nickel plating solution (1) was added dropwise to the suspension for 10 minutes at a drop rate of 6 mL/min. After that, it is dropped for 40 minutes at a dropping rate of 2 mL/min, and then dropped for 80 minutes at a dropping rate of 0.8 mL/min, thereby controlling the content of boron incorporated into the plating film. Electroless nickel-boron alloy plating was applied to the surface of the substrate particles A (thickness: 0.02 μm). Subsequently, the solution temperature was set to 70° C., and the nickel plating solution (2) was gradually added dropwise to carry out electroless nickel plating to obtain a suspension (2).

After that, by filtering the suspension (2), the particles are taken out, washed with water, and dried to form a nickel-boron alloy conductive layer (thickness: 0.02 μm) on the surface of the substrate particle A and a pure layer. A particle having a nickel conductive layer (thickness of 0.08 μm) and a first conductive portion (main metal: nickel, thickness of 0.1 μm) was obtained.

10 parts by weight of the obtained particles were dispersed in 500 parts by weight of ion-exchanged water using an ultrasonic processor to obtain a suspension.

A plating solution (pH 10.0) containing 0.02 mol/L palladium sulfate, 0.04 mol/L ethylenediamine as a complexing agent, 0.06 mol/L ammonium formate as a reducing agent, and a crystal modifier was prepared.

While stirring the resulting suspension at 50° C., the palladium plating solution was gradually added to perform electroless palladium plating to form a second conductive portion. Electroless palladium plating was terminated when the thickness of the second conductive portion reached 20 nm. Conductive particles (particle size: 3.24 μm) were obtained in which the second conductive portion (palladium layer, thickness: 0.02 μm) was arranged on the surface of the first conductive portion.

A conductive film and a connection structure were obtained in the same manner as in Example 1, except that the obtained conductive particles were used.

(Comparative example 1)
Particles in which the first conductive part (conductive layer containing nickel, thickness 0.1 μm) is arranged on the surface of the substrate particles A similar to those of Example 1 were prepared as conductive particles of Comparative Example 1. Note that unlike Example 1, no surface treatment with an organosilicon compound was performed.

A conductive film and a connection structure were obtained in the same manner as in Example 1, except that the obtained conductive particles were used.

(Comparative example 2)
A particle was prepared in which the first conductive part (a conductive layer containing nickel, thickness 0.1 μm) was arranged on the surface of the substrate particle A similar to that of Example 1.

10 parts by weight of the particles and 0.5 parts by weight of monohexyl phosphate were added to a mixture of 25 parts by weight of pure water and 25 parts by weight of ethanol, and the mixture was stirred at 50° C. for 1 hour. Then, it was filtered and dried in a vacuum dryer at 100° C. for 8 hours to obtain conductive particles having a film formed of monohexyl phosphate on the outer surface of the conductive layer.

A conductive film and a connection structure were obtained in the same manner as in Example 1, except that the obtained conductive particles were used.

(Comparative Example 3)
A particle was prepared in which the first conductive part (a conductive layer containing nickel, thickness 0.1 μm) was arranged on the surface of the substrate particle A similar to that of Example 1.

10 parts by weight of the particles and 0.5 parts by weight of 1,2,3-benzotriazole were added to a mixture of 25 parts by weight of pure water and 25 parts by weight of ethanol, and the mixture was stirred at 50° C. for 1 hour. Then, it was filtered and dried in a vacuum dryer at 100° C. for 8 hours to obtain conductive particles having a film formed of 1,2,3-benzotriazole on the outer surface of the conductive layer.

A conductive film and a connection structure were obtained in the same manner as in Example 1, except that the obtained conductive particles were used.

(Comparative Example 4)
A particle was prepared in which the first conductive part (a conductive layer containing nickel, thickness 0.1 μm) was arranged on the surface of the substrate particle A similar to that of Example 1.

10 parts by weight of the particles and 0.5 parts by weight of 2-mercaptobenzothiazole were added to a mixture of 25 parts by weight of pure water and 25 parts by weight of ethanol, and the mixture was stirred at 50° C. for 1 hour. Then, it was filtered and dried in a vacuum dryer at 100° C. for 8 hours to obtain conductive particles having a film formed of 2-mercaptobenzothiazole on the outer surface of the conductive layer.

A conductive film and a connection structure were obtained in the same manner as in Example 1, except that the obtained conductive particles were used.

(Comparative Example 5)
A particle dispersion similar to that of Example 1 was prepared.

To 50 parts by weight of ethanol, 10 parts by weight of water, 0.8 parts by weight of acetic acid, and 1.5 parts by weight of organosilicon compound A were added, and the mixture was stirred at room temperature for 200 minutes to obtain solution A.

The above particle dispersion was added to the above solution A, heated to 50° C. and stirred to obtain conductive particles whose surfaces were modified with the organosilicon compound A.

A conductive film and a connection structure were obtained in the same manner as in Example 1, except that the obtained conductive particles were used.

(evaluation)
(1) Initial connection resistance A
A connection resistance A between opposing electrodes of the obtained connection structure was measured by a four-probe method. From the relationship of voltage=current×resistance, the connection resistance can be obtained by measuring the voltage when a constant current flows. Also, the connection resistance A was determined according to the following criteria.

[Evaluation Criteria for Connection Resistance A]
○○○: Connection resistance A is 2.0 Ω or less ○○: Connection resistance A is over 2.0 Ω and 3.0 Ω or less ○: Connection resistance A is over 3.0 Ω and 5.0 Ω or less △: Connection resistance A is 5 .0 Ω to 10 Ω ×: Connection resistance A exceeds 10 Ω

(2) Connection resistance B after reliability test
The connection structure obtained in the above (1) initial connection resistance evaluation was left under the conditions of 85° C. and 85% relative humidity. After 1000 hours from the start of standing, the connection resistance B between the electrodes was measured by the four-probe method in the same manner as in (3) Evaluation of the connection resistance A described above. Also, the connection resistance B was determined according to the following criteria.

[Determination Criteria for Connection Resistance B]
○○○: Connection resistance B is less than 1.25 times the connection resistance A ○○: Connection resistance B is 1.25 times or more and less than 1.5 times the connection resistance A ○: Connection resistance B is less than the connection resistance A 1.5 times or more and less than 2 times △: Connection resistance B is 2 times or more and less than 3 times of connection resistance A ×: Connection resistance B is 3 times or more of connection resistance A

(3) Short-circuit occurrence rate As an IC for short-circuit occurrence rate evaluation, the following IC (comb tooth TEG (test element group) having a space 2.5 times larger than the particle diameter of the conductive particles) was prepared.

Outer diameter: 1.5 x 13mm
Thickness: 0.5mm

Bump specifications: gold plating, height 15 μm, size 25×140 μm, space between bumps 2.5 times the particle diameter of the conductive particles (8.0 μm if the conductive particles are 3.2 μm)
The resulting anisotropic conductive film was sandwiched between an IC for short circuit rate evaluation and a glass substrate having a pattern corresponding to the IC for evaluation, and heated and pressed under the same connection conditions as in the production of the connection structure. and got the connection. The rate of occurrence of short circuits in the obtained connections was determined. The short-circuit occurrence rate is calculated by "number of short-circuit occurrences/total number of spaces". From the viewpoint of manufacturing a practical connection structure, the short circuit occurrence rate is preferably less than 1 ppm.

Details and results are shown in Tables 1-3 below.

In Tables 1 and 2 above, the types of organosilicon functional groups are as follows.

A: Organosilicon functional group having an alkyl group having 10 carbon atoms B: Organosilicon functional group having a benzotriazole group C: Organosilicon functional group having a (meth)acryloyl group D: Organosilicon functional group having an epoxy group

DESCRIPTION OF SYMBOLS 1... Conductive particle 2... Base material particle 3... Conductive part 11... Conductive particle 11a... Protrusion 12... Conductive part 12a... Protrusion 13... Core substance 14... Insulating substance 21... Conductive particle 21a... Protrusion 22... Conductive part 22a... Protrusion 22A... First conductive portion 22Aa... Protrusion 22B... Second conductive portion 22Ba... Protrusion 31... Conductive particle 51... Connection structure 52... First member to be connected 52a... First electrode 53... Second 2 connection object member 53a... 2nd electrode 54... connection part

Claims (13)

having a conductive portion,
having at least two organosilicon functional groups on the outer surface of the conductive portion;
The outer surface of the conductive part has an organosilicon functional group having an antirust effect,
The conductive particles , wherein the organosilicon functional group having an antirust effect is an organosilicon functional group having a benzotriazole group . having a conductive portion,
having at least two organosilicon functional groups on the outer surface of the conductive portion;
The outer surface of the conductive part has an organosilicon functional group having an antirust effect,
On the outer surface of the conductive portion, at least one of the organosilicon functional group having the antirust effect and the organosilicon functional group having a (meth)acryloyl group and the organosilicon functional group having an epoxy group is formed. and conductive particles. the total number of the organosilicon functional groups of at least one of the (meth)acryloyl group-containing organosilicon functional groups and the epoxy group-containing organosilicon functional groups; 3. The conductive particles according to claim 2, wherein the ratio to number is 0.05 or more and 0.95 or less. 4. The conductive particle according to any one of claims 1 to 3 , wherein the outer surface of said conductive portion has an organosilicon functional group having a (meth)acryloyl group. 4. The conductive particle according to any one of claims 1 to 3, wherein the outer surface of said conductive portion has an organosilicon functional group having an epoxy group. 6. The conductive particles according to any one of claims 1 to 5 , wherein the outer surface of the conductive part has an organosilicon functional group having an alkyl group having 1 to 22 carbon atoms. 7. The conductive particle according to any one of claims 1 to 6 , wherein the outer surface of said conductive part has an organosilicon functional group having a (meth)acryloyl group and an organosilicon functional group having an epoxy group. The conductivity according to any one of claims 1 to 7 , wherein the surface area covered with at least two kinds of the organosilicon functional groups is 60% or more and 100% or less out of 100% of the surface area of the conductive portion. particle. The conductive particle according to any one of claims 1 to 8 , comprising a substrate particle and a conductive portion arranged on the surface of the substrate particle. The conductive particles according to any one of claims 1 to 9 , having projections on the outer surface of the conductive portion. Conductive particles according to any one of claims 1 to 10 , comprising an insulating substance disposed on the outer surface of the conductive portion. A conductive material comprising the conductive particles according to any one of claims 1 to 11 and a binder resin. a first connection target member having a first electrode on its surface;
a second connection target member having a second electrode on its surface;
A connecting portion connecting the first connection target member and the second connection target member,
The material of the connection portion is the conductive particles according to any one of claims 1 to 11 , or a conductive material containing the conductive particles and a binder resin,
A connection structure, wherein the first electrode and the second electrode are electrically connected by the conductive particles.

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