JP6798771B2 - Method for manufacturing conductive particles, method for manufacturing conductive material, and method for manufacturing connecting structure - Google Patents

Description

The present invention relates to a conductive particle in which a conductive portion is arranged on the surface of the base particle and a method for producing the conductive particle. The present invention also relates to a conductive material and a connecting structure using the above conductive particles.

Anisotropic conductive materials such as anisotropic conductive pastes and anisotropic conductive films are widely known. In the anisotropic conductive material, a plurality of conductive particles are dispersed in the binder resin.

In order to obtain various connection structures, the anisotropic conductive material may be used, for example, for connecting a flexible printed circuit board and a glass substrate (FOG (Film on Glass)) or connecting a semiconductor chip and a flexible printed circuit board (COF (COF). It is used for Chip on Film)), connection between a semiconductor chip and a glass substrate (COG (Chip on Glass)), and connection between a flexible printed circuit board and a glass epoxy substrate (FOB (Film on Board)).

As an example of the conductive particles, Patent Document 1 below discloses a polymer particle and a conductive particle having a conductive metal layer on the surface of the polymer particle. The fracture point load of the polymer particles is 9.8 mN (1.0 gf) or less. Further, Patent Document 1 describes that the 10% K value of the polymer particles may be 7350 N / mm ² (750 kgf / mm ² ) to 49000 N / mm ² (5000 kgf / mm ² ).

WO2012 / 020799A1

When using an anisotropic conductive material, for example, when electrically connecting an electrode of a semiconductor chip and an electrode of a glass substrate, an anisotropic conductive material containing conductive particles is arranged on the glass substrate. Next, the semiconductor chips are laminated and heated and pressurized. As a result, the anisotropic conductive material is cured, and the electrodes are electrically connected to each other via the conductive particles to obtain a connection structure. An example of a connection structure obtained by such a method is a liquid crystal display element.

In the liquid crystal display element, the frame of the liquid crystal panel is narrowed and the glass substrate is thinned. For this reason, distortion occurs in the mounting portion, and display unevenness is likely to occur. In order to suppress display unevenness, it is required to crimp at a low temperature during crimping.

However, crimping at a low temperature increases the melt viscosity of the anisotropic conductive material. Therefore, when crimping at a low temperature, it is necessary to increase the pressure in order to prevent voids from being generated. As a result, a large stress is applied to the conductive particles. In addition, in a manufacturing method other than the above-mentioned manufacturing method of the connection structure, and even before the use of the conductive particles, a large stress may be applied to the conductive particles.

In the conventional conductive particles as described in Patent Document 1, cracks may occur in the conductive layer when stress is applied to the conductive particles. As a result, when the electrodes are connected to each other to obtain a connection structure, the initial connection resistance may increase or the continuity reliability may decrease.

Furthermore, when a connection structure made of conductive connections using conventional conductive particles is exposed in the presence of an acid, the connection resistance between the electrodes may increase.

An object of the present invention is to provide a method for producing conductive particles and conductive particles in which the conductive portion is less likely to be cracked even when stress is applied to the conductive particles.

Another object of the present invention is to provide a conductive material and a connecting structure using the above conductive particles.

According to a broad aspect of the present invention, the base particle is provided with a conductive portion arranged on the surface of the base particle, and the compressive elastic modulus when the base particle is compressed by 10% is 1000 N / mm ^2. or more, 25000N / mm ² or less, the internal stress of the conductive parts, -100N / mm ² or more and 100 N / mm ² or less, the conductive particles are provided.

In a specific aspect of the conductive particles according to the present invention, the particle size of the base particles is 1.0 μm or more and 5.0 μm or less.

In certain aspects of the conductive particles according to the present invention, the substrate particles are resin particles or organic-inorganic hybrid particles.

In certain aspects of the conductive particles according to the present invention, the conductive particles have a plurality of protrusions on the outer surface of the conductive portion.

In a specific aspect of the conductive particles according to the present invention, the conductive particles are a plurality of core substances in which the outer surface of the conductive portion is raised so as to form a plurality of the protrusions in the conductive portion. To be equipped.

In a specific aspect of the conductive particles according to the present invention, the Mohs hardness of the material of the core material is 5 or more.

In a specific aspect of the conductive particles according to the present invention, the surface area of the portion having the protrusion is 30% or more in the total surface area of the outer surface of the conductive portion of 100%.

In certain aspects of the conductive particles according to the present invention, the conductive particles include an insulating material disposed on the outer surface of the conductive portion.

According to a broad aspect of the present invention, a conductive portion is formed on the surface of the base material particles by a plating treatment using a plating solution, and the base material particles and the conductivity arranged on the surface of the base material particles. comprising the step of obtaining the conductive particles and a part, the compression modulus when the base particle is compressed 10% 1000 N / mm ² or more and 25000N / mm ² or less, using the plating solution, wherein Under the same conditions as the plating process, the internal stress of the plating film when a plate-shaped conductive material having a surface area of 774 mm ² on the flat surface where the plating film is formed is coated with a plating film having a thickness of 5 μm is -100 N / mm. ^A method for producing conductive particles having a value of ² or more and 100 N / mm ² or less is provided.

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

According to a broad aspect of the present invention, a connection portion connecting the first connection target member, the second connection target member, the first connection target member, and the second connection target member. Provided is a connecting structure in which the connecting portion is formed of the above-mentioned conductive particles or is formed of a conductive material containing the conductive particles and a binder resin.

The conductive particle according to the present invention, the conductive portion on the surface of the base particle is disposed, compression modulus when the base particle is compressed 10% 1000 N / mm ² or more, 25000N / mm ² or less , and the internal stress of the conductive parts, -100N / mm ² or more, because it is 100 N / mm ² or less, even if a stress is applied to the conductive particles can be hardly cracked in the conductive portion.

The method for producing conductive particles according to the present invention includes a step of forming a conductive portion on the surface of the base material particles by a plating process using a plating solution to obtain conductive particles, and using 10% of the base material particles. compressive modulus upon compression 1000 N / mm ² or more and 25000N / mm ² or less, using the above plating solution under the same conditions as the plating process, the surface area of the flat portion where the plating film is formed 774Mm ² the internal stress of the plating film when the plate-like conductive material covered with a plating film having a thickness of 5μm at that, -100N / mm ² or more, since it is 100 N / mm ² or less, less likely cracked the conductive portion be able to.

FIG. 1 is a cross-sectional view showing conductive particles according to the 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 the conductive particles according to the third embodiment of the present invention. FIG. 4 is a front 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 will be described below.

(Conductive particles)
The conductive particles according to the present invention include base particles and conductive portions arranged on the surface of the base particles.

The conductive particle according to the present invention, the compression modulus when the base particle is compressed 10% (10% K value) is 1000 N / mm ² or more and 25000N / mm ² or less. Furthermore, the conductive particles according to the present invention, the internal stress of the conductive parts, -100N / mm ² or more and 100 N / mm ² or less.

In the method for producing conductive particles according to the present invention, a conductive portion is formed on the surface of the base material particles by a plating treatment using a plating solution, and is arranged on the base material particles and the surface of the base material particles. A step of obtaining conductive particles having the above-mentioned conductive portion is provided.

The method for producing a conductive particle according to the present invention, the compression modulus when the base particle is compressed 10% (10% K value) is 1000 N / mm ² or more and 25000N / mm ² or less. Further, in the method for producing conductive particles according to the present invention, a plate-shaped conductive material having a flat surface portion having a surface area of 774 mm ^{2 on} which a plating film is formed is formed by using the above plating solution under the same conditions as the above plating treatment. the internal stress of the plating film when coated with the plating film having a thickness of 5μm is, -100N / mm ² or more and 100 N / mm ² or less.

In the present invention, since the above-described configuration is provided, even if stress is applied to the conductive particles, it is possible to prevent the conductive portion from cracking. By forming the conductive portion having a specific internal stress with respect to the base particle having a specific 10% K value, the conductive portion is less likely to be cracked effectively. The present inventors have found that it is necessary to control both the 10% K value of the substrate particles and the internal stress of the conductive portion in order to prevent the conductive portion from cracking. Furthermore, the present inventors have found that in order to make it difficult for the conductive portion to crack, the 10% K value of the base material particles and the internal stress of the conductive portion should satisfy the above relationship. It was.

Further, by making the conductive portion less likely to crack, even if the conductive material is cured at a relatively low temperature and crimping is performed in a state where the melt viscosity of the conductive material is high, the connection resistance between the electrodes is sufficiently low and conduction is achieved. It is possible to obtain a connection structure having excellent reliability. By using the conductive material according to the present invention, it is possible to make the frame to be connected narrower and thinner.

Further, in the present invention, since the conductive portion is less likely to be cracked, the connecting structure may be obtained by using the conductive particles exposed in the presence of the acid, or the connecting structure may be exposed in the presence of the acid. However, the connection resistance can be kept low.

From the viewpoint of further lowering the connection resistance and further increasing the conduction reliability between the electrodes, the 10% K value of the base particles is preferably 2000 N / mm ² or more, more preferably 3000 N / mm ² or more. It is preferably 23000 N / mm ² or less, and more preferably 20000 N / mm ² or less.

From the viewpoint of further lowering the connection resistance and further increasing the conduction reliability between the electrodes, the internal stress of the conductive portion is preferably -80 N / mm ² or more, more preferably -50 N / mm ² or more. It is preferably 80 N / mm ² or less, more preferably 50 N / mm ² or less.

Examples of the method for controlling the internal stress include a method for adjusting a complexing agent, a method for adjusting a brightener, and the like.

Methods for reducing the internal stress of the conductive portion include addition of a complexing agent to the plating solution, addition of an organic brightener to the plating solution, addition of a metallic brightener to the plating solution, and the like. Can be mentioned.

Examples of the complexing agent include carboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, valeric acid and oxalic acid; hydroxycarboxylic acids such as lactic acid, oxalic acid, tartaric acid, glycolic acid, malic acid and citric acid; alanine and valine. , Tyrosine, glycine, aspartic acid and amino acids such as histidine. Only one kind of the complexing agent may be used, or two or more kinds thereof may be used in combination.

Regarding the brightener, examples of the metal brightener include lead compounds, bismuth compounds, and thallium compounds. Specific examples of these compounds include sulfates of metals (lead, bismuth, and thallium) constituting the compound. Examples thereof include carbonates, acetates, nitrates and hydrochlorides. Only one kind of the above metal brightener may be used, or two or more kinds may be used in combination.

Examples of the organic brightener include saccharin, sodium naphthalenedisulfonate, sodium 1,5-naphthalene sulfonate, sodium allyl sulfonate, paratoluene sulphonamide, sodium propagil sulfonate, butine diol, propagyl alcohol, coumarin, and formalin. , Ethoxylated polyethyleneimine, polyalkylimine, polyethyleneimine, gelatin, dextrin, thiourea, polyvinylpyrrolidone, polyvinyl alcohol, polyethylene glycol, polyacrylamide, silicic acid, nicotinic acid, benzalacetone and the like. Only one kind of the organic brightener may be used, or two or more kinds may be used in combination.

In particular, the addition of an organic brightener is effective in reducing the internal stress in the gold layer. Preferred examples of the brightener include sodium 1,5-naphthalene sulfonate, paratoluene sulfonamide and the like. Only one kind of the brightener may be used, or two or more kinds may be used in combination.

The 10% K value of the base particles can be measured as follows.

Using a microcompression tester, the substrate particles are compressed on the smoothing indenter end face of a cylinder (diameter 50 μm, made of diamond) under the condition that a maximum test load of 90 mN is applied over 30 seconds at 25 ° C. The load value (N) and compressive displacement (mm) at this time are measured. From the obtained measured values, the compressive elastic modulus can be calculated by the following formula. As the microcompression tester, for example, "Fisherscope H-100" manufactured by Fisher Co., Ltd. is used.

K value (N / mm ² ) = (3/2 ^1/2 ) ・ F ・ S ^-3/2・ R- ^{1 / 2}
F: Load value (N) when the base particle is compressed and deformed by 10%
S: Compressive displacement (mm) when the substrate particles are compressed and deformed by 10%
R: Radius of substrate particles (mm)

The compressive elastic modulus universally and quantitatively represents the hardness of the substrate particles. By using the compressive elastic modulus, the hardness of the base particle can be expressed quantitatively and uniquely.

The internal stress can be measured as follows.

Prepare a plate-shaped conductive material having the same composition as the conductive part. When the conductive portion is formed by using a plating solution, a plating film is formed on the conductive material by using the same plating solution as when forming the conductive portion and under the same plating treatment conditions. The conductive material is a plate-shaped conductive material having a surface area of 774 mm ² in a flat portion on which the plating film is formed. Using this conductive material, the internal stress is measured at 25 ° C. using a strip type electrodeposition stress tester (“683EC analyzer” manufactured by Fujikasei Co., Ltd.).

From the viewpoint of further lowering the connection resistance and further increasing the conductivity reliability, the conductive particles preferably have a plurality of protrusions on the outer surface of the conductive portion. Further, it is preferable that the conductive particles include a plurality of core substances in which the outer surface of the conductive portion is raised so as to form the plurality of protrusions in the conductive portion.

From the viewpoint of further lowering the connection resistance and further increasing the conduction reliability, the surface area of the portion having the protrusions is preferably 10% or more, more preferably 30% or more, of the total surface area of the conductive particles of 100%. It is preferably 95% or less, more preferably 90% or less.

Hereinafter, the present invention will be specifically described with reference to the drawings.

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

The conductive particle 1 shown in FIG. 1 has a base particle 2 and a conductive portion 3. The conductive portion 3 is arranged on the surface of the base particle 2. In the first embodiment, the conductive portion 3 is in contact with the surface of the base particle 2. The conductive particles 1 are coated particles in which the surface of the base particle 2 is coated with the conductive portion 3. In the conductive particles 1, the conductive portion 3 is a single-layer conductive portion (conductive layer).

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 the conductive surface and do not have protrusions on the outer surface of the conductive portion 3. The conductive particles 1 are spherical.

As described above, the conductive particles according to the present invention may not have protrusions on the conductive surface, may not have protrusions on the outer surface of the conductive portion, and may be spherical. .. Further, the conductive particles 1 do not have an insulating substance, unlike the conductive particles 11 and 21 described later. 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.

The conductive particle 11 shown in FIG. 2 has a base 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 base particle 2 so as to be in contact with the base particle 2. In the conductive particles 11, the conductive portion 12 is a single-layer conductive portion (conductive layer).

The conductive particles 11 have a plurality of protrusions 11a on the conductive surface. The conductive portion 12 has a plurality of protrusions 12a on the outer surface. A plurality of core substances 13 are arranged on the surface of the base particle 2. The plurality of core substances 13 are embedded in the conductive portion 12. The core material 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 the plurality of core substances 13, and protrusions 11a and 12a are formed.

The conductive particles 11 have an insulating substance 14 arranged on the outer surface of the conductive portion 12. At least a part of the outer surface of the conductive portion 12 is covered with the insulating substance 14. The insulating substance 14 is formed of a material having an insulating property and is an insulating particle. As described above, the conductive particles according to the present invention may have an insulating substance arranged on the outer surface of the conductive portion. However, the conductive particles according to the present invention do not necessarily have an insulating substance.

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

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

Only the conductive portion is different between the conductive particles 11 and the conductive particles 21. That is, in the conductive particles 11, the conductive portion 22 having a one-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.

The first conductive portion 22A is arranged on the surface of the base particle 2. The first conductive portion 22A is arranged between the base particle 2 and the second conductive portion 22B. The first conductive portion 22A is in contact with the base particle 2. Therefore, the first conductive portion 22A is arranged on the surface of the base 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 protrusions 21a on the conductive surface. In the conductive particles 21, the conductive portion 22 has a plurality of protrusions 22a on the outer surface. The first conductive portion 22A has a protrusion 22Aa on the outer surface. The second conductive portion 22B has a plurality of protrusions 22Ba on the outer surface. In the conductive particles 21, the conductive portion 22 is a two-layer conductive portion (conductive layer).

Hereinafter, other details of the conductive particles will be described. In the following description, "(meth) acrylic" means one or both of "acrylic" and "methacrylic", and "(meth) acrylate" means one or both of "acrylate" and "methacrylate". means.

[Base particles]
Examples of the base material particles include resin particles, inorganic particles other than metal particles, organic-inorganic hybrid particles, and metal particles. The base particle may be a core-shell particle having a core and a shell arranged on the surface of the core. The core may be an organic core. The shell may be an inorganic shell. Of these, base particle particles excluding metal particles are preferable, and resin particles, inorganic particles excluding metal particles, or organic-inorganic hybrid particles are more preferable. Resin particles or organic-inorganic hybrid particles are particularly preferable because they are more excellent due to the effects of the present invention.

The base material particles are preferably resin particles formed of a resin. When connecting the electrodes using the conductive particles, the conductive particles are placed between the electrodes and then pressure-bonded to compress the conductive particles. When the base material particles are resin particles, the conductive particles are easily deformed during the crimping, and the contact area between the conductive particles and the electrode becomes large. Therefore, the continuity reliability between the electrodes is high.

Various organic substances are preferably used as the resin for forming the resin particles. Examples of the resin for forming the resin particles include polyolefin resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyisobutylene and polybutadiene; acrylic resins such as polymethylmethacrylate and polymethylacrylate; poly. Alkylene terephthalate, polycarbonate, polyamide, phenol formaldehyde resin, 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, polysulfone, polyphenylene Polymers obtained by polymerizing one or more of various polymerizable monomers having an oxide, polyacetal, polyimide, polyamideimide, polyether ether ketone, polyether sulfone, and ethylenically unsaturated group, etc. Can be mentioned. Since the hardness of the base material particles can be easily controlled within a suitable range, the resin for forming the resin particles is obtained by polymerizing one or more polymerizable monomers having a plurality of ethylenically unsaturated groups. It is preferably a polymer.

When the resin particles are obtained by polymerizing a monomer having an ethylenically unsaturated group, the monomer having an ethylenically unsaturated group includes a non-crosslinkable monomer and a crosslinkable monomer. And can be mentioned.

Examples of the non-crosslinkable monomer include styrene-based monomers such as styrene and α-methylstyrene; carboxyl group-containing monomers such as (meth) acrylic acid, maleic acid, and maleic anhydride; and methyl ( Meta) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) Alkyl (meth) acrylates such as meta) acrylate and isobornyl (meth) acrylate; oxygen atoms such as 2-hydroxyethyl (meth) acrylate, glycerol (meth) acrylate, polyoxyethylene (meth) acrylate and glycidyl (meth) acrylate. Contains (meth) acrylates; nitrile-containing monomers such as (meth) acrylonitrile; vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, and propyl vinyl ether; acid vinyl esters such as vinyl acetate, vinyl butyrate, vinyl laurate, vinyl stearate, etc. Classes: unsaturated hydrocarbons such as ethylene, propylene, isoprene, and butadiene; halogen-containing monomers such as trifluoromethyl (meth) acrylate, pentafluoroethyl (meth) acrylate, vinyl chloride, vinyl fluoride, and chlorostyrene. Can be mentioned.

Examples of the crosslinkable monomer include tetramethylol methanetetra (meth) acrylate, tetramethylol methanetri (meth) acrylate, tetramethylol methanedi (meth) acrylate, trimethyl propanetri (meth) acrylate, and dipenta. Elythritol hexa (meth) acrylate, dipenta erythritol penta (meth) acrylate, glycerol tri (meth) acrylate, glycerol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) Polyfunctional (meth) acrylates such as acrylates, (poly) tetramethylene glycol di (meth) acrylates, 1,4-butanediol di (meth) acrylates; triallyl (iso) cyanurate, triallyl trimellitate, divinylbenzene, Examples thereof include silane-containing monomers such as diallyl phthalate, diallyl acrylamide, diallyl ether, γ- (meth) acryloxipropyltrimethoxysilane, trimethoxysilylstyrene, and vinyltrimethoxysilane.

The resin particles can be obtained by polymerizing the polymerizable monomer having an ethylenically unsaturated group by a known method. Examples of this method include a method of suspension polymerization in the presence of a radical polymerization initiator, and a method of swelling and polymerizing a monomer together with a radical polymerization initiator using non-crosslinked seed particles.

When the base material particles are inorganic particles other than metal or organic-inorganic hybrid particles, examples of the inorganic material for forming the base material particles include silica and carbon black. The inorganic substance is preferably not a metal. The particles formed of the silica are not particularly limited, but for example, after hydrolyzing a silicon compound having two or more hydrolyzable alkoxysilyl groups to form crosslinked polymer particles, firing is performed if necessary. Examples include particles obtained by doing so. Examples of the organic-inorganic hybrid particles include organic-inorganic hybrid particles formed of a crosslinked alkoxysilyl polymer and an acrylic resin.

When the base material particles are metal particles, examples of the metal as the material of the metal particles include silver, copper, nickel, silicon, gold, and titanium. However, the base material particles are preferably not metal particles and preferably not copper particles.

The particle size of the base particles is preferably 0.1 μm or more, more preferably 1.0 μm or more, still more preferably 1.5 μm or more, particularly preferably 2.0 μm or more, preferably 1000 μm or less, more preferably. It is 500 μm or less, more preferably 300 μm or less, further preferably 50 μm or less, even more preferably 30 μm or less, particularly preferably 6.0 μm or less, and most preferably 5.0 μm or less. The particle size of the base particles may be 4.0 μm or less. When the particle size of the base material particles is equal to or larger than the above lower limit, the contact area between the conductive particles and the electrodes becomes large, so that the conduction reliability between the electrodes becomes even higher, and the conductive particles are connected via the conductive particles. The connection resistance between the electrodes becomes even lower. Further, when the conductive portion is formed on the surface of the base material particles by electroless plating, it becomes difficult to aggregate, and it becomes difficult to form the aggregated conductive particles. When the particle size of the base material particles is not more than the above upper limit, the conductive particles are easily sufficiently compressed, the connection resistance between the electrodes is further lowered, and the distance between the electrodes is further reduced.

The particle size of the base material particles indicates the diameter when the base material particles are spherical, and indicates the maximum diameter when the base material particles are not spherical.

The particle size of the base particles is particularly preferably 2.0 μm or more and 5.0 μm or less. When the particle size of the base material particles is in the range of 2.0 to 5.0 μm, small conductive particles can be obtained even if the distance between the electrodes is small and the thickness of the conductive portion is increased.

Further, the particle size of the base particles is particularly preferably 1.0 μm or more and 5.0 μm or less. When the particle size of the base particles is satisfied, if the 10% K value of the base particles and the internal stress of the conductive portion satisfy the above relationship, cracking of the conductive portion is considerably less likely to occur. The connection resistance is reduced even more effectively. Further, since the conductive portion is less likely to be cracked, the particle size of the base material particles may be 4.0 μm or less.

[Conductive part]
The metal for forming the conductive portion is not particularly limited. Examples of the metal include gold, silver, palladium, copper, platinum, zinc, iron, tin, lead, ruthenium, aluminum, cobalt, indium, nickel, chromium, titanium, antimony, bismuth, tarium, germanium, cadmium and silicon. And these alloys and the like. Examples of the metal include tin-doped indium oxide (ITO) and solder. Among them, an alloy containing tin, nickel, palladium, copper or gold is preferable, and nickel or palladium is preferable because the connection resistance between the electrodes can be further lowered.

Like the conductive particles 1 and 11, the conductive portion may be formed by one layer. Like the conductive particles 21, 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 by a plurality of layers, the outermost layer is preferably a gold layer, a nickel layer, a palladium layer, a copper layer or an alloy layer containing tin and silver, and is preferably a gold layer. Is more preferable. When the outermost layer is these preferable conductive layers, the connection resistance between the electrodes becomes even lower. Further, when the outermost layer is a gold layer, the corrosion resistance is further improved.

The method of forming the conductive portion on the surface of the base particle is not particularly limited. Examples of the method for forming the conductive portion include a method by electroless plating, a method by electroplating, a method by physical vapor deposition, and a method of coating a metal powder or a paste containing the metal powder and a binder on the surface of the substrate particles. And so on. Among them, the method by electroless plating is preferable because the formation of the conductive portion is easy. Examples of the method by physical vapor deposition include methods such as vacuum vapor deposition, ion plating, and ion sputtering.

The particle size of the conductive particles is preferably 0.5 μm or more, more preferably 1 μm or more, preferably 520 μm or less, more preferably 500 μm or less, still more preferably 100 μm or less, still more preferably 50 μm or less, particularly preferably. Is 20 μm or less. When the particle diameter of the conductive particles is equal to or greater than the above lower limit and equal to or less than the above upper limit, the contact area between the conductive particles and the electrodes becomes sufficiently large and the conductive portion is formed when the electrodes are connected using the conductive particles. It becomes difficult for agglomerated conductive particles to be formed when the particles are formed. In addition, the distance between the electrodes connected via the conductive particles does not become too large, and the conductive portion does not easily peel off from the surface of the substrate particles. Further, when the particle diameter of the conductive particles is not less than the above lower limit and not more than the above upper limit, the conductive particles can be suitably used for the use of the conductive material.

The particle diameter of the conductive particles means the diameter when the conductive particles are spherical, and means the maximum diameter when the conductive particles have a shape other than the spherical shape.

The thickness of the conductive portion (thickness of the entire conductive portion) is preferably 0.005 μm or more, more preferably 0.01 μm or more, preferably 10 μm or less, more preferably 1 μm or less, still more preferably 0.5 μm or less. Particularly preferably, it is 0.3 μm or less. The thickness of the conductive portion is the thickness of the entire conductive layer when the conductive portion has multiple layers. When the thickness of the conductive portion is not less than the above lower limit and not more than the above upper limit, sufficient conductivity is obtained, and the conductive particles are not too hard and the conductive particles are sufficiently deformed at the time of connection between the electrodes. ..

When the conductive portion is formed of a plurality of layers, the thickness of the outermost conductive layer is preferably 0.001 μm or more, more preferably 0.01 μm or more, still more preferably 0.12 μm or more, and is preferable. Is 0.5 μm or less, more preferably 0.1 μm or less. When the thickness of the conductive layer of the outermost layer is not less than the above lower limit and not more than the above upper limit, the coating by the conductive layer of the outermost layer becomes uniform, the corrosion resistance becomes sufficiently high, and the connection resistance between the electrodes is further increased. It gets lower. Further, when the outermost layer is a gold layer, the thinner the gold layer, the lower the cost.

The thickness of the conductive portion can be measured by observing the cross section of the conductive particles, for example, using a transmission electron microscope (TEM).

From the viewpoint of effectively increasing the conductivity, the conductive particles preferably have a conductive portion containing nickel. In 100% by weight of the conductive portion containing nickel, the content of nickel is preferably 50% by weight or more, more preferably 65% by weight or more, still more preferably 70% by weight or more, still more preferably 75% by weight or more, still more preferably. Is 80% by weight or more, particularly preferably 85% by weight or more, and most preferably 90% by weight or more. The nickel content is preferably 100% by weight (total amount) or less, 99% by weight or less, or 95% by weight or less in the 100% by weight of the conductive portion containing nickel. When the nickel content is at least the above lower limit, the connection resistance between the electrodes becomes even lower. Further, when the oxide film on the surface of the electrode or the conductive portion is small, the connection resistance between the electrodes tends to decrease as the nickel content increases.

The method for measuring the content of the metal contained in the conductive portion can use various known analytical methods and is not particularly limited. Examples of this measuring method include an absorption analysis method and a spectrum analysis method. In the above absorption analysis method, a frame absorptiometer, an electric heating furnace absorptiometer, or the like can be used. Examples of the spectrum analysis method include a plasma emission spectrometry method and a plasma ion source mass spectrometry method.

When measuring the average content of the metal contained in the conductive portion, it is preferable to use an ICP emission spectrometer. Examples of commercially available ICP emission spectrometers include ICP emission spectrometers manufactured by HORIBA.

The conductive portion may contain phosphorus or boron in addition to nickel. Further, the conductive portion may contain a metal other than nickel. When a plurality of metals are contained in the conductive portion, the plurality of metals may be alloyed.

The content of phosphorus or boron in 100% by weight of the conductive portion containing nickel and phosphorus or boron is preferably 0.1% by weight or more, more preferably 1% by weight or more, preferably 10% by weight or less, more preferably. Is 5% by weight or less. When the content of phosphorus or boron is not more than the above lower limit and the above upper limit, the resistance of the conductive portion is further lowered, and the conductive portion contributes to the reduction of the connection resistance.

[Core material]
The conductive particles preferably have protrusions on the conductive surface. The conductive particles preferably have protrusions on the outer surface of the conductive portion. It is preferable that the number of the protrusions is plurality. An oxide film is often formed on the surface of the electrode connected by the conductive particles. Further, an oxide film is often formed on the surface of the conductive portion of the conductive particles. By using the conductive particles having the protrusions, the conductive particles are arranged between the electrodes and then crimped, so that the oxide film is effectively removed by the protrusions. Therefore, the electrodes and the conductive particles can be brought into contact with each other more reliably, and the connection resistance between the electrodes can be lowered. Further, when the conductive particles have an insulating substance on the surface, or when the conductive particles are dispersed in the binder resin and used as a conductive material, the protrusions of the conductive particles cause the conductive particles to be connected to the electrode. The resin in between can be effectively eliminated. Therefore, the continuity reliability between the electrodes is further increased.

By embedding the core substance in the conductive portion, it is easy for the conductive portion to have a plurality of protrusions on the outer surface. However, the core material does not necessarily have to be used in order to form protrusions on the conductive surface of the conductive particles and the surface of the conductive portion.

As a method of forming the above-mentioned protrusions, a method of forming a conductive portion by electroless plating after adhering a core material to the surface of the base particle, and a method of forming a conductive portion by electroless plating on the surface of the base particle. , A method of adhering the core material and further forming the conductive portion by electroless plating, and a method of adding the core material in the middle of forming the conductive portion by electroless plating on the surface of the base particle.

Examples of the material of the core substance include a conductive substance and a non-conductive substance. Examples of the conductive substance include metals, metal oxides, conductive non-metals such as graphite, and conductive polymers. Examples of the conductive polymer include polyacetylene and the like. Examples of the non-conductive substance include silica, alumina, barium titanate and zirconia. Among them, metal is preferable because the conductivity can be increased and the connection resistance can be effectively lowered. The core material is preferably metal particles. As the metal that is the material of the core material, the metal mentioned as the material of the conductive material can be appropriately used.

Specific examples of the material of the core material include barium titanate (Mohs hardness 4.5), nickel (Mohs hardness 5), silica (silicon dioxide, Mohs hardness 6-7), titanium oxide (Mohs hardness 7), and zirconia. (Mohs hardness 8 to 9), alumina (Mohs hardness 9), tungsten carbide (Mohs hardness 9), diamond (Mohs hardness 10) and the like can be mentioned. The inorganic particles are preferably nickel, silica, titanium oxide, zirconia, alumina, tungsten carbide or diamond, more preferably silica, titanium oxide, zirconia, alumina, tungsten carbide or diamond, and titanium oxide or zirconia. , Alumina, Tungsten Carbide or Diamond, and particularly preferably Zirconia, Alumina, Tungsten Carbide or Diamond. The Mohs hardness of the material of the core material is preferably 5 or more, more preferably 6 or more, still more preferably 7 or more, and particularly preferably 7.5 or more.

The shape of the core substance is not particularly limited. The shape of the core material is preferably lumpy. Examples of the core material include particulate lumps, agglomerates in which a plurality of fine particles are aggregated, and amorphous lumps.

The average diameter (average particle size) of the core substance is preferably 0.001 μm or more, more preferably 0.05 μm or more, preferably 0.9 μm or less, and more preferably 0.2 μm or less. When the average diameter of the core material is at least the above lower limit and at least the above upper limit, the connection resistance between the electrodes is effectively lowered.

The "average diameter (average particle diameter)" of the core substance indicates a number average diameter (number average particle diameter). The average diameter of the core material is obtained by observing 50 arbitrary core materials with an electron microscope or an optical microscope and calculating an average value.

The number of the above-mentioned protrusions per one of the above-mentioned conductive particles is preferably 3 or more, and 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 and the like.

The average height of the plurality of protrusions is preferably 0.001 μm or more, more preferably 0.05 μm or more, preferably 0.9 μm or less, and more preferably 0.2 μm or less. When the average height of the protrusions is at least the above lower limit and at least the above upper limit, the connection resistance between the electrodes is effectively lowered.

The height of the protrusion is a virtual line (broken line shown in FIG. 2) of the conductive portion on the line connecting the center of the conductive particle and the tip of the protrusion (broken line L1 shown in FIG. 2) assuming that there is no protrusion. L2) The distance from the top (on the outer surface of the spherical conductive particles assuming that there is no protrusion) to the tip of the protrusion is shown. That is, in FIG. 2, the distance from the intersection of the broken line L1 and the broken line L2 to the tip of the protrusion is shown.

[Insulating substance]
It is preferable that the conductive particles include an insulating substance arranged on the surface of the conductive portion. In this case, if conductive particles are used for the connection between the electrodes, short circuits between adjacent electrodes can be further prevented. Specifically, when a plurality of conductive particles come into contact with each other, an insulating substance exists between the plurality of electrodes, so that it is possible to prevent a short circuit between the electrodes adjacent to each other in the lateral direction rather than between the upper and lower electrodes. By pressurizing the conductive particles with the two electrodes at the time of connection between the electrodes, the insulating substance between the conductive portion of the conductive particles and the electrodes can be easily removed. When the conductive particles have a plurality of protrusions on the outer surface of the conductive portion, the insulating substance between the conductive portion of the conductive particles and the electrodes can be more easily removed.

The insulating substance is preferably insulating particles because the insulating substance can be more easily removed during pressure bonding between the electrodes.

Specific examples of the insulating resin that is the material of the insulating substance include polyolefins, (meth) acrylate polymers, (meth) acrylate copolymers, block polymers, thermoplastic resins, crosslinked products of thermoplastic resins, and heat. Examples thereof include curable resins and water-soluble resins.

The average diameter (average particle diameter) of the insulating substance can be appropriately selected depending on the particle diameter of the conductive particles, the use of the conductive particles, and the like. The average diameter (average particle size) of the insulating substance is preferably 0.005 μm or more, more preferably 0.01 μm or more, preferably 1 μm or less, and more preferably 0.5 μm or less. When the average diameter of the insulating substance 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 average diameter of the insulating particles is not more than the above upper limit, it is not necessary to increase the pressure too high in order to eliminate the insulating substance between the electrodes and the conductive particles when connecting the electrodes. There is no need to heat to high temperature.

The "average diameter (average particle diameter)" of the insulating substance indicates a number average diameter (number average particle diameter). The average diameter of the insulating substance is determined by using a particle size distribution measuring device or the like.

(Conductive material)
The conductive material according to the present invention includes the above-mentioned conductive particles and a binder resin. The conductive particles are preferably dispersed in the binder resin and used as a conductive material. The conductive material is preferably an anisotropic conductive material. It is preferable that the conductive particles and the conductive material are used for electrical connection between the electrodes, respectively. The conductive material is preferably a circuit connection material.

The binder resin is not particularly limited. As the binder resin, an insulating resin is generally used. Examples of the binder resin include vinyl resins, thermoplastic resins, curable resins, thermoplastic block copolymers, and elastomers. Only one kind of the binder resin may be used, or two or more kinds may be used in combination.

Examples of the vinyl resin include vinyl acetate resin, acrylic resin, styrene resin and the like. Examples of the thermoplastic resin include polyolefin resins, ethylene-vinyl acetate copolymers, and polyamide resins. Examples of the curable resin include epoxy resin, urethane resin, polyimide resin, unsaturated polyester resin and the like. 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 copolymer include a styrene-butadiene-styrene block copolymer, a styrene-isoprene-styrene block copolymer, a hydrogenated additive of a styrene-butadiene-styrene block copolymer, and a styrene-isoprene. -Hydrogen additives for styrene block copolymers and the like can be mentioned. Examples of the elastomer include styrene-butadiene copolymer rubber and acrylonitrile-styrene block copolymer rubber.

The conductive material and the binder resin preferably contain a thermoplastic component or a thermosetting component. The conductive material and the binder resin may contain a thermoplastic component or may contain a thermosetting component. The conductive material and the binder resin preferably contain a thermosetting component. The thermosetting component preferably contains a curable compound that can be cured by heating and a thermosetting agent. The thermosetting agent is preferably a thermal cation curing initiator. The curable compound curable by heating and the thermosetting agent are used in an appropriate compounding ratio so that the binder resin is cured. When the binder resin contains a thermal cation curing initiator, an acid is likely to be contained in the cured product. However, by using the conductive particles according to the present invention, the connection resistance between the electrodes can be kept low.

In addition to the conductive particles and the binder resin, the conductive material includes, for example, a filler, a bulking agent, a softening agent, a plasticizer, a polymerization catalyst, a curing catalyst, a colorant, an antioxidant, a heat stabilizer, and a photostabilizer. It may contain various additives such as an agent, an ultraviolet absorber, a lubricant, an antistatic agent and a flame retardant.

The conductive material can be used as a conductive paste, a conductive film, or the like. When the conductive material is a conductive film, a film containing no conductive particles may be laminated on the conductive film containing the 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, particularly preferably 70% by weight or more, and preferably 70% by weight or more. It is 99.99% by weight or less, more preferably 99.9% by weight or less. When the content of the binder resin is not less than the above lower limit and not more than the above upper limit, the conductive particles are efficiently arranged between the electrodes, and the conduction reliability of the connecting target member connected by the conductive material is further increased.

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, preferably 80% by weight or less, and more preferably 60% by weight. Below, it is 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 not less than the above lower limit and not more than the above upper limit, the conduction reliability between the electrodes is further increased.

(Connection structure)
A connection structure can be obtained by connecting the members to be connected using the conductive particles or a conductive material containing the conductive particles and a binder resin.

The connection structure includes a first connection target member, a second connection target member, and a connection portion connecting the first and second connection target members, and the connection portion is the conductive portion of the present invention. It is preferably a connection structure formed of the conductive particles or a conductive material containing the conductive particles and the binder resin. When conductive particles are used, the connecting portion itself is the conductive particles. That is, the first and second connection target members are connected by the conductive particles.

FIG. 4 schematically shows a connection structure using conductive particles according to the first embodiment of the present invention in a front sectional view.

The connection structure 51 shown in FIG. 4 connects 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. Be prepared. The connecting portion 54 is formed by curing a conductive material containing the conductive particles 1. In FIG. 4, the conductive particles 1 are shown schematicly for convenience of illustration. Conductive particles 11, 21 and the like may be used instead of the conductive particles 1.

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

The method for manufacturing the connection structure is not particularly limited. As an example of the method for manufacturing the connection structure, the conductive material is arranged between the first connection target member and the second connection target member, and after obtaining a laminate, the laminate is heated. And a method of pressurizing and the like. The pressurizing pressure is about 9.8 × 10 ^{4 to} 4.9 × 10 ⁶ Pa. The heating temperature is about 120 to 220 ° C.

Specific examples of the connection target member include electronic components such as semiconductor chips, capacitors and diodes, and electronic components such as printed circuit boards, flexible printed circuit boards, glass epoxy boards and circuit boards such as glass substrates. The connection target member is preferably an electronic component. The conductive particles are preferably used for electrical connection of electrodes in electronic components.

Examples of the electrodes provided on the connection target member include metal electrodes such as gold electrodes, nickel electrodes, tin electrodes, aluminum electrodes, copper electrodes, silver electrodes, molybdenum electrodes and tungsten electrodes. When the connection target member is a flexible printed substrate, the electrode is preferably a gold electrode, a nickel electrode, a tin 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, or a tungsten electrode. When the electrode is an aluminum electrode, it may be an electrode formed only of aluminum, or an electrode in which an aluminum layer is laminated on the surface of a metal oxide layer. Examples of the material of 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 element include Sn, Al and Ga.

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

( Reference example 1)
(1) Preparation of Conductive Particles To a monomer solution containing 80 parts by weight of tetramethylolmethane tetraacrylate and 20 parts by weight of acrylonitrile, 1.5 parts by weight of benzoyl peroxide as a polymerization catalyst was added and dissolved to dissolve the monomer solution. Obtained. This monomer solution was added to 700 mL of a 3 wt% polyvinyl alcohol aqueous solution, and the mixture was stirred and suspended to obtain a monomer suspension.

The monomer suspension was then heated to 85 ° C. to initiate the polymerization reaction and hold this state for 10 hours until the reaction was complete. The obtained solid content was filtered, washed with hot water to remove polyvinyl alcohol, and then classified to obtain base particle A having a particle size of 2.5 μm. The base particle A was dispersed in 100 parts by weight of an alkaline solution containing 5% by weight of a palladium catalyst solution using an ultrasonic disperser, and then the base particle A was taken out by filtering the solution. .. Next, the base particle A was added to 100 parts by weight of a 1 wt% dimethylamine borane solution to activate the surface of the substrate particle A. The surface-activated substrate particles A were thoroughly washed with water, and then added to 500 parts by weight of distilled water and dispersed to obtain a dispersion liquid. Next, 1 g of an alumina particle slurry (average particle diameter 150 nm) was added to the dispersion over 3 minutes to obtain a suspension containing base particles to which a core substance was attached.

Further, a nickel plating solution (pH 8.5) containing 0.23 mol / L of nickel sulfate, 0.92 mol / L of dimethylamine borane and 0.5 mol / L of succinic acid (complexing agent A) was prepared.

While stirring the obtained suspension at 60 ° C., the nickel plating solution was gradually added dropwise to the suspension to perform electroless nickel plating. Then, by filtering the suspension, the particles are taken out, washed with water, and dried to arrange a nickel-boron conductive layer (thickness 0.1 μm) on the surface of the base particle A, and the surface is a conductive layer. Conductive particles were obtained. The surface area of the portion with protrusions was 70% of the total surface area of the outer surface of the conductive portion.

(2) Preparation of Connection Structure A 20 parts by weight of an epoxy compound (“EP-3300P” manufactured by Nagase ChemteX Corporation) which is a thermosetting compound and an epoxy compound (“EPICLON HP-” manufactured by DIC Co., Ltd.) which is a thermosetting compound. 4032D ") 15 parts by weight, thermosetting agent thermal cation generator (Sun Aid" SI-60 "manufactured by Sanshin Chemical Co., Ltd.) 5 parts by weight, and filler silica (average particle size 0.25 μm) 20 parts by weight. , And the obtained conductive particles were added so that the content in 100% by weight of the compound was 10% by weight, and then the mixture was stirred at 2000 rpm for 5 minutes using a planetary stirrer. An anisotropic conductive paste was obtained.

A glass substrate having an Al—Ti 4% electrode pattern (Al—Ti 4% electrode thickness 1 μm) having an L / S of 20 μm / 20 μm on the upper surface was prepared. Further, a semiconductor chip having a gold electrode pattern (gold electrode thickness 20 μm) having an L / S of 20 μm / 20 μm on the lower surface was prepared.

An anisotropic conductive paste immediately after production was applied to the upper surface of the glass substrate so as to have a thickness of 20 μm to form an anisotropic conductive material layer. Next, the semiconductor chips were laminated on the upper surface of the anisotropic conductive material layer so that the electrodes face each other. Then, while adjusting the temperature of the head so that the temperature of the anisotropic conductive material layer becomes 170 ° C., the pressure heating head is placed on the upper surface of the semiconductor chip, and a pressure of 150 MPa is applied to apply the anisotropic conductive material layer. Was cured at 180 ° C. to obtain a connection structure A.

(3) Preparation of Connection Structure B Similar to Connection Structure A except that a pressure heating head is placed on the upper surface of the semiconductor chip and a pressure of 100 MPa is applied to cure the anisotropic conductive material layer at 100 ° C. The connection structure B was obtained.

( Reference example 2)
Conductive particles were obtained in the same manner as in Reference Example 1 except that the alumina particle slurry was changed to a nickel particle slurry, and connection structures A and B were further obtained.

( Reference example 3)
Conductive particles were obtained in the same manner as in Reference Example 1 except that the protrusions were formed by adjusting the amount of precipitation to be partially changed during the formation of the conductive portion without using the particle slurry for forming the protrusions. Further, connection structures A and B were obtained.

( Reference example 4)
Conductive particles were obtained in the same manner as in Reference Example 1 except that the complexing agent A in the nickel plating solution was changed to propionic acid (complexing agent B), and connection structures A and B were further obtained. ..

(Example 5)
Conductive particles were obtained in the same manner as in Reference Example 1 except that paratoluene sulfonamide (brightening agent A) was added to the nickel plating solution, and connection structures A and B were further obtained.

(Example 6)
Conductive particles were obtained in the same manner as in Example 5, except that the alumina particle slurry was changed to a nickel particle slurry, and connection structures A and B were further obtained.

(Example 7)
Conductive particles were obtained in the same manner as in Example 5 except that the protrusions were formed by adjusting the amount of precipitation to be partially changed when the conductive portion was formed without using the particle slurry for forming the protrusions. Further, connection structures A and B were obtained.

(Example 8)
Conductive particles were obtained in the same manner as in Reference Example 1 except that sodium 1,5-naphthalenesulfonate (brightener B) was added to the nickel plating solution as a brightener, and the connection structures A and B were further obtained. Got

(Example 9)
Conductivity in the same manner as in Reference Example 1 except that the complexing agent A in the nickel plating solution was changed to propionic acid (complexing agent B) and paratoluene sulfonamide (glazing agent A) was added as a brightener. Sex particles were obtained, and connection structures A and B were further obtained.

(Example 10)
Same as Reference Example 1 except that the complexing agent A in the nickel plating solution was changed to propionic acid (complexing agent B) and sodium 1,5-naphthalenesulfonate (brightening agent B) was added as a brightener. Then, conductive particles were obtained, and connection structures A and B were further obtained.

(Example 11)
Conductive particles were obtained in the same manner as in Example 5, except that the thickness of the conductive portion was changed to 0.15 μm, and connection structures A and B were further obtained.

(Example 12)
Conductive particles were obtained in the same manner as in Example 5, except that the thickness of the conductive portion was changed to 0.23 μm, and connection structures A and B were further obtained.

(Example 13)
Conductive particles were obtained in the same manner as in Example 5 except that the base particle B having a particle diameter of 1.5 μm was used by changing only the particle diameter from the base particle A, and further, a connecting structure was obtained. A and B were obtained.

(Example 14)
Conductive particles were obtained in the same manner as in Example 5 except that the base particles C having a particle diameter of 3.5 μm were used by changing only the particle diameter from the base particles A, and further, a connecting structure was obtained. A and B were obtained.

(Example 15)
Conductive particles were obtained in the same manner as in Example 5 except that the base particle D having a particle diameter of 6.0 μm was used by changing only the particle diameter from the base particle A, and further, a connecting structure was obtained. A and B were obtained.

( Reference example 16)
Conductive particles were obtained in the same manner as in Reference Example 1 except that the surface area of the portion with protrusions was changed to 25% in the total surface area of the outer surface of the conductive portion, and the connecting structures A and B were further formed. Obtained.

(Example 17)
The surface of divinylbenzene copolymer resin particles (“Micropearl SP-202” manufactured by Sekisui Chemical Industry Co., Ltd.) having a particle size of 2.0 μm is coated with an inorganic shell (silica, thickness 250 nm) using a condensation reaction by a sol-gel reaction. A coated core-shell type organic-inorganic hybrid particle (base particle E) was obtained. Conductive particles were obtained in the same manner as in Example 5 except that the base particle A was changed to the base particle E, and connection structures A and B were further obtained.

(Example 18)
300 g of a 0.13 wt% ammonia aqueous solution was placed in a 500 mL reaction vessel equipped with a stirrer and a thermometer. Next, in an aqueous ammonia solution in the reaction vessel, 4.1 g of methyltrimethoxysilane, 19.2 g of vinyltrimethoxysilane, and 0.7 g of silicone alkoxy oligomer (“X-41-1053” manufactured by Shin-Etsu Chemical Co., Ltd.) The mixture with was added slowly. After advancing the hydrolysis and condensation reaction with stirring, 2.4 mL of a 25 wt% aqueous ammonia solution was added, and then the particles were isolated from the aqueous ammonia solution, and the obtained particles were subjected to an oxygen partial pressure of ^10-17 atm. , 350 ° C. for 2 hours to obtain organic-inorganic hybrid particles (base particle F) having a particle size of 2.5 μm. Conductive particles were obtained in the same manner as in Example 5 except that the base particle A was changed to the base particle F, and connection structures A and B were further obtained.

(Example 19)
100 mmol of methyl methacrylate and N, N, N-trimethyl-N-2-methacryloyloxyethyl in a 1000 mL separable flask equipped with a 4-port separable cover, stirring blade, three-way cock, cooling tube and temperature probe. A monomer composition containing 1 mmol of ammonium chloride and 1 mmol of 2,2'-azobis (2-amidinopropane) dihydrochloride was weighed in ion-exchanged water so as to have a solid content of 5% by weight, and then at 200 rpm. The mixture was stirred and polymerized at 70 ° C. for 24 hours under a nitrogen atmosphere. After completion of the reaction, the reaction was freeze-dried to obtain insulating particles having an ammonium group on the surface, having an average particle diameter 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 wt% aqueous dispersion of the insulating particles.

10 g of the conductive particles obtained in Example 5 was 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 filtering with a 3 μm mesh filter, the mixture was further washed with methanol and dried to obtain conductive particles to which insulating particles were attached, and further connected structures A and B were obtained.

When observed with a scanning electron microscope (SEM), only one coating layer of insulating particles was formed on the surface of the conductive particles. When the covering area of the insulating particles (that is, the projected area of the particle diameter of the insulating particles) was calculated for an area of 2.5 μm from the center of the conductive particles by image analysis, the covering ratio was 30%.

(Comparative Example 1)
Conductive particles were obtained in the same manner as in Reference Example 1 except that the complexing agent A was not added to the nickel plating solution, and connection structures A and B were further obtained.

(Comparative Example 2)
Conductive particles were obtained in the same manner as in Reference Example 1 except that the complexing agent A in the nickel plating solution was changed to aspartic acid (complexing agent C), and connection structures A and B were further obtained.

(Evaluation)
(1) Compressive modulus (10% K value) when the base particle is compressed by 10%
The compressive elastic modulus (10% K value) of the obtained substrate particles was measured by the method described above using a microcompression tester (“Fisherscope H-100” manufactured by Fisher).

(2) Internal stress of the conductive portion A plating film was formed on the conductive material under the same plating treatment conditions using the same plating solution at the time of forming the conductive portion in the conductive particles. This conductive material was a plate-shaped conductive material having a surface area of 774 mm ² in a flat portion on which a plating film was formed. Using this conductive material, the internal stress was measured using a strip-type electrodeposition stress tester (“683EC analyzer” manufactured by Fujikasei Co., Ltd.) by the method described above.

(3) Cracking of Conductive Part In the obtained connection structures A and B, the peeled surface was observed after peeling the semiconductor chip. It was evaluated whether or not the conductive portion was cracked in the 50 conductive particles. The cracks in the conductive part were judged according to the following criteria.

[Criteria for cracking conductive parts]
○○○: The ratio of the number of conductive particles having cracks in the conductive part out of 50 conductive particles is 0 or more and less than 10 ○○: Cracks occur in the conductive part out of 50 conductive particles. The ratio of the number of conductive particles is 10 or more and less than 20. ◯: The ratio of the number of conductive particles in which the conductive portion is cracked is 20 or more and less than 30 out of 50 conductive particles. : The ratio of the number of conductive particles having cracks in the conductive portion out of 50 conductive particles is 30 or more and less than 40. ×: Conductive with cracks in the conductive portion among 50 conductive particles. The ratio of the number of particles is 40 or more

(4) Initial connection resistance X
Measurement of connection resistance:
The connection resistance X between the opposite electrodes of the obtained connection structures A and B was measured by the 4-terminal method. Further, the initial connection resistance X was determined according to the following criteria.

[Evaluation criteria for initial connection resistance X]
○ ○ ○: Connection resistance X is 2.0Ω or less ○ ○: Connection resistance X is more than 2.0Ω and 3.0Ω or less ○: Connection resistance X is more than 3.0Ω and 5.0Ω or less △: Connection resistance X Exceeds 5.0Ω and 10Ω or less ×: Connection resistance X exceeds 10Ω

(4) Connection resistance Y after exposure to acid conditions (long-term reliability)
The obtained connection structures A and B were left in a high-temperature and high-humidity tank at 85 ° C. and 85% humidity for 100 hours. By leaving the connection structures A and B under the above conditions, the reaction between the water infiltrated into the binder resin and the acid contained in the binder resin causes the presence of acid in the connection portion between the electrodes in the connection structures A and B. It was exposed to the bottom for a certain period of time. In the connection structures A and B after being left to stand, the connection resistance Y between the opposing electrodes of the connection structure was measured by the four-terminal method. In addition, the connection resistance Y after exposure to the presence of acid was determined according to the following criteria.

[Evaluation criteria for connection resistance Y after exposure to acid conditions]
○ ○ ○: Connection resistance Y is less than 1 times the connection resistance X ○ ○: Connection resistance Y is 1 time or more and less than 1.5 times the connection resistance X ○: Connection resistance Y is 1.5 times or more the connection resistance X Less than 2 times Δ: Connection resistance Y is 2 times or more and less than 5 times the connection resistance X ×: Connection resistance Y is 5 times or more the connection resistance X

The results are shown in Table 1 below.

Further, in Examples 5, 11 and 12, the evaluation results of the cracks in the conductive portions of the connection structures A and B, the initial connection resistance and the connection resistance after the reliability test are all "○○○". Examples 11 and 12 were superior to Example 5 in terms of specific numerical values of the cracks in the conductive portions of the connection structures A and B, the initial connection resistance, and the connection resistance after the reliability test.

1 ... Conductive particles 2 ... Base material particles 3 ... Conductive parts 11 ... Conductive particles 11a ... Protrusions 12 ... Conductive parts 12a ... Protrusions 13 ... Core material 14 ... Insulating material 21 ... Conductive particles 21a ... Protrusions 22 ... Conductive parts 22a ... Projection 22A ... First conductive part 22Aa ... Projection 22B ... Second conductive part 22Ba ... Projection 51 ... Connection structure 52 ... First connection target member 52a ... First electrode 53 ... Second connection target member 53a ... Second electrode 54 ... Connection

Claims (10)

Forming a conductive portion by plating using a plating solution on the surface of the base particle, and the base particle, the conductive particles Ru and a said conductive portion disposed on the surface of the substrate particles With the process of getting
The plating solution contains a brightener and contains
Compression modulus when the base particle is compressed 10% 1000 N / mm ² or more and 25000N / mm ² or less,
A plate-shaped conductive material having a surface area of 774 mm ² on a flat surface portion on which a plating film is formed using the plating solution under the same conditions as the plating treatment (however, the plate-shaped conductive material is the same as the conductive portion. internal stress of the plating film when coated with a) the same composition in the plated film thickness 5μm is, -100N / mm ² or more and 100 N / mm ² or less, the production method of the conductive particles. The method for producing conductive particles according to claim 1, wherein the substrate particles have a particle size of 1.0 μm or more and 5.0 μm or less. The method for producing conductive particles according to claim 1 or 2, wherein the base particles are resin particles or organic-inorganic hybrid particles. The method for producing conductive particles according to any one of claims 1 to 3, wherein conductive particles having a plurality of protrusions on the outer surface of the conductive portion are obtained . The method for producing conductive particles according to claim 4, wherein conductive particles having a plurality of core substances that raise the outer surface of the conductive portion so as to form the plurality of protrusions in the conductive portion are obtained . .. The method for producing conductive particles according to claim 5, wherein the material of the core substance has a Mohs hardness of 5 or more. The production of conductive particles according to any one of claims 4 to 6, wherein conductive particles having a surface area of 30% or more of the portion having protrusions in 100% of the total surface area of the outer surface of the conductive portion are obtained . Method . The method for producing conductive particles according to any one of claims 1 to 7, wherein conductive particles having an insulating substance arranged on the outer surface of the conductive portion are obtained . A step of obtaining conductive particles by the method for producing conductive particles according to any one of claims 1 to 8.
A method for producing a conductive material, comprising a step of blending the conductive particles and a binder resin to obtain a conductive material containing the conductive particles and the binder resin. A step of obtaining conductive particles by the method for producing conductive particles according to any one of claims 1 to 8.
The connection portion for connecting the first connection target member and the second connection target member is formed of the conductive particles, or is formed of a conductive material containing the conductive particles and a binder resin. obtaining a first connection object member, wherein the second connection object member, the first connection object member and the front Stories second connection object member and the connecting structure Ru and a connecting portion connecting the body With process
In the resulting connection structure, the connecting portion, the conductive or is formed by the particles, or is formed by the front Kishirube material cost, the manufacturing method of the connection structure.

Images