JP2002203428A - Conductive paste composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductive paste composition with high magnetic sensitivity and low resistance since composite particles having good content balance of a conductive component and a magnetic component can be used, and suitable for forming a bump or a wiring electrode, and suitable for fine printing because clogging prevention performance of a block in paste coating or sag prevention performance in heat curing is good. SOLUTION: This conductive paste composition contains (A) composite particles containing a conductive component and a ferromagnetic component and (B) binder resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a conductive paste composition. More specifically, it is excellent in preventing clogging of the plate at the time of paste application or dripping at the time of heat curing, and a paste with low resistance can be obtained even if the content ratio of the magnetic component is increased, and high-definition bumps or wiring Formation of electrodes, etc.
Alternatively, the present invention relates to a conductive paste composition suitable for forming a circuit board for mounting a semiconductor element such as an IC or an LSI.

[0002]

BACKGROUND OF THE INVENTION In recent years, a method of using a conductive paste composition which is inexpensive and has good productivity for forming bumps or wiring on a printed circuit board has been widely used. For example, a conductive paste composition is screen-printed on a substrate to form a predetermined pattern, which is then heat-treated, the solvent is evaporated and dried, and the binder resin is cured to form a circuit conductor. Is what you do.

[0003] Such a conductive paste composition uses a thermosetting resin such as an epoxy resin or a phenol resin as a binder resin, and dissolves the binder resin in an organic solvent. The powder is dispersed to form a paste. In particular, conductive paste compositions using silver powder as conductive particles,
Because of its good conductivity, it is widely used for forming printed circuit board conductors, multilayer circuit board conductors, electrode wiring, and circuit conductors such as bump electrodes (protruding electrodes).

[0004] Such a conductive paste composition is printed on a substrate through a screen plate or a metal plate, and the conventional conductive paste has a relatively low viscosity in order to prevent pattern dripping after printing. It was prepared at a high setting. However, when a fine pattern is printed through a screen plate or a metal plate having a small opening diameter, the paste easily clogs the plate, and a satisfactory high-definition wiring pattern or bump cannot be obtained. In addition, when printing was performed by increasing the plate thickness in order to print bumps or the like having a high height, the discharge amount of the paste was reduced, and it was necessary to perform printing with multiple coatings, resulting in poor workability. .

Therefore, the present inventors have used a conductive paste composition containing conductive particles and ferromagnetic particles and provided a magnet under a substrate applied in a printing process. It has been found that clogging of a plate during printing can be prevented and a high-definition wiring pattern or bump can be obtained (Japanese Patent Application Nos. 2000-136989 and 2000-299039).

By the way, in order to form a fine conductive portion or the like more precisely and promptly by transferring the conductive paste composition onto a substrate by such a magnetic force, the conductive paste composition needs to be added to the conductive paste composition. It is also considered effective to increase the content of the contained ferromagnetic particles to some extent to increase the magnetic sensitivity to magnetic force. However, when the content of the ferromagnetic particles is increased, the resistivity of the conductive paste may increase due to the contact resistance between the magnetic particles or between the conductive particles and the magnetic particles.

As a result, the inventors of the present application have conducted intensive studies. As a result, when composite particles having both the properties of conductivity and ferromagnetism are used, even if the ferromagnetic component is increased, the conductive particles obtained from the conductive paste can be obtained. It has been found that an increase in the resistance of the portion can be suppressed and a high-definition bump or wiring pattern can be formed, and the present invention has been completed.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems associated with the prior art described above, and is suitable for forming fine bumps or wiring electrodes, etc., has high magnetic sensitivity, and is suitable for forming a plate when applying paste. It is an object of the present invention to provide a conductive paste composition which is excellent in clogging prevention and sagging prevention during heat curing and can provide a low-resistance conductive portion.

[0009]

SUMMARY OF THE INVENTION The conductive paste composition according to the present invention comprises:
It is characterized by containing (A) composite particles containing a conductive component and a ferromagnetic component, and (B) a binder resin. The ferromagnetic component is contained in the composite particles (A).
The composite particles (A) are preferably contained at a ratio of 5 to 70% by weight based on the total weight.

The composite particles (A) preferably have the surface of the ferromagnetic component covered with the conductive component. It is preferable that the conductive paste composition is applied to a base on which a magnet is provided below the base and used to form a conductive part on the base.

[0011]

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, the conductive paste composition of the present invention will be specifically described, and a method of using the conductive paste composition will be described. [Conductive paste composition] The conductive paste composition of the present invention comprises (A) composite particles containing a conductive component and a ferromagnetic component, and (B) a binder resin.

(A) Contains a conductive component and a ferromagnetic component
The composite particle (A) containing a conductive component and a ferromagnetic component used in the present invention is composed of a component having conductivity (conductive component) and a component having ferromagnetism (ferromagnetic component). . Such a composite particle (A) contains a conductive component and a ferromagnetic component in one particle. Specifically, for example, when the conductive component and the ferromagnetic component are in an alloy state,
When the surface of one of the components is coated with the other by plating or vapor deposition, the other is carried on one surface, the other is contained in one of the components in a dispersed state, or a combination thereof. And the like. Therefore, the conductive component and the ferromagnetic component are not substantially integrated and independently exist in the binder resin.

In the present invention, since the conductive component and the ferromagnetic component form such composite particles, for example,
Even if the ferromagnetic component is increased, an increase in the resistivity of the conductive paste can be suppressed. As the conductive component used in the present invention, those used in known conductive paste compositions can be used and are not particularly limited.

The conductive component is preferably at least one metal selected from gold, silver, copper, tin, platinum, palladium and the like. Among these, silver and gold can be more preferably used. Examples of the ferromagnetic component used in the present invention include metals such as Fe, Ni, Co, Gd, Tb, and Dy, Fe—Ni, Fe—Co, Fe—Al, and Fe—.
Si-Al, Fe-Ni-Mo, Al-Ni-Co, S
Alloys and intermetallic compounds such as m-Co and Nd-Fe-B are exemplified. Fe ₂ O ₃ , Fe ₂ O ₃ —NiO—ZnO,
_{Fe 2 O 3 -CuO-ZnO,} Fe 2 O 3 -MnO-Zn
Ferrite compounds such as O ₂ , Fe ₂ O ₃ —SrO, and Fe ₂ O ₃ —BaO can also be used.

Among these, Ni, Fe ₂ O ₃ —Sr
O can be preferably used. The shape of the composite particles (A) comprising a conductive component and a ferromagnetic component is not particularly limited, but specific examples thereof include a sphere, a particle, a plate, a flake, a scale, a whisker, a rod, and a filament. Shape and the like. In these shapes, it is preferable that the shape is spherical, granular, flaky, or scaly. The composite particles having these shapes are used alone or in combination of two or more.

When the composite particles (A) are spherical or granular, they are uniformly mixed and dispersed in a binder resin,
In order to obtain excellent conductivity, the average particle size is usually 0.1.
It is preferably in the range of 1 to 20 μm,
It is more preferably within a range of 15 μm, and 1 to 10
More preferably, it is within the range of μm. In such a composite particle (A), the magnetic component may be easily oxidized in some cases, and it is preferable that the surface of the ferromagnetic component is coated with the conductive component. Alternatively, the composite particles (A) are preferably those in which the concentration of the conductive component near the surface of the particle is higher than the average concentration of the conductive component in the particle.

In order to obtain better conductivity, two or more kinds of composite particles having different average particle sizes, for example, a composite particle having an average particle size of 5 to 20 μm and a composite particle having an average particle size of 0.1 to 5 μm are used.
It is also possible to use a mixture with composite particles of less than μm. When a plurality of composite particles having different average particle sizes are used as described above, composite particles having a small average particle size can enter between composite particles having a large average particle size. Therefore,
The composite particles can be filled into the binder resin at a high density.

The content ratio of the conductive component and the ferromagnetic component contained in the composite particles (A) used in the present invention is preferably based on the total weight of the composite particles (A). The component is contained at a ratio of 5 to 70% by weight, the conductive component is contained at a ratio of 30 to 95% by weight, more preferably the ferromagnetic component is contained at a ratio of 20 to 65% by weight, and the conductive component is 35 to 35% by weight. To 80% by weight, particularly preferably the ferromagnetic component is in a proportion of 40 to 60% by weight,
It is desirable that the ratio of the conductive component is 40 to 60% by weight (however, the content of the ferromagnetic component + the content of the conductive component = 100% by weight).

In the present invention, low resistivity can be maintained even when the content ratio of the conductive component and the ferromagnetic component is within the above range. In particular, even when the content ratio of the ferromagnetic component is 40% by weight or more, a decrease in conductivity can be suppressed, and satisfactory performance as an electrode can be obtained. If the content of the ferromagnetic component is less than 5% by weight, the metal plate is likely to be clogged with the paste, and it may be difficult to form wirings and bumps. On the other hand, if the ferromagnetic component exceeds 70% by weight, the conductivity may be reduced and satisfactory performance as an electrode may not be exhibited.

Such a composite particle (A) can be prepared by a known method and is not limited. For example,
When one of the components is coated with the other by plating or the like, electroless plating such as chemical plating can be used. Also, for example, composite particles in an alloy state can be prepared by a known method such as a gas atomizing method. Further, the composite particles prepared by the gas atomization method may be formed, for example, by using a known alloy manufacturing method to increase the concentration of the conductive component near the particle surface, suppress oxidation of the particle surface, and form a composite particle having a lower resistance. Can also.

More specifically, a powder having an average particle size of 1 to 10 μm is collected from an alloy powder of 20 to 80% by weight of a conductive component and a ferromagnetic component by a classifier, and the powder is used in ultrapure water. After applying sonic dispersion and sufficiently immersing the surface,
Composite particles can be obtained by eluting only Cu on the surface in a sulfuric acid bath of 10 to 10% by volume (Japanese Patent Laid-Open No. 2000-290701).

For example, even if the particles are fine or flaky, composite particles containing a large amount of a conductive component near the surface of the composite particles can be produced. Specifically, such composite particles are obtained by adding 3 to 50% by weight of an oxidized conductive metal such as silver oxide to a ferromagnetic powder such as Ni,
It can be obtained by mechanically bonding an oxidized conductive metal to a magnetic substance while pulverizing, and further reducing in a reducing atmosphere at a temperature of 120 to 400 ° C. (JP-A-11-3)
No. 10806).

Further, the concentration of the conductive component near the surface of the composite particles can be increased from the average concentration by melting the alloy powder of the conductive metal and the ferromagnetic metal in a high-temperature plasma gas and then rapidly cooling and solidifying the alloy powder. (Japanese Patent Laid-Open No. 5-
No. 105921). Further, for example, when the particle diameter is 0.1.
When it is desired to obtain a fine powder of composite particles having a diameter of about 1 to 10 μm, the ferromagnetic particles in the form of fine powder are dispersed in primary particles by a fluid jet mill treatment in an inert atmosphere, and the dispersion treatment is performed. The heated ferromagnetic fine powder is heated under reduced pressure in an inert atmosphere, and the heated ferromagnetic fine powder is charged into a rotating container containing a conductive component as a sputtering source, and the container is rotated in a certain direction. A fluidized bed of ferromagnetic fine powder is formed, and the coating (coating) material is coated on the fluidized ferromagnetic fine powder by sputtering the conductive component while rotating the container, and the coated fine powder is introduced with an inert gas. And vacuum evacuation are combined to obtain fine powdery composite particles having a conductive component firmly and uniformly coated by taking them out of the rotating container on the principle of a vacuum cleaner (Japanese Patent No. 2909). 44 JP).

(B) Binder Resin In the present invention, the binder constituting the conductive paste composition is not particularly limited as long as it is a paste that adheres to a base material under certain conditions. In the present invention, the binder resin is contained. Preferably. As the binder resin,
After printing the conductive paste composition, a thermosetting type (B1) for curing the resin and a baking type (B) for burning the resin
2) can be preferably used.

(B1) Binder Resin (Thermosetting Type) Examples of the thermosetting type binder resin include (B1-a)
Weight average molecular weight (mean polystyrene equivalent weight average molecular weight by gel permeation method; hereinafter the same) is 3
An epoxy resin in the range of 00 to 5,000 and / or
Or (B1-b) having a structural unit derived from a compound having an ethylenic double bond and an epoxy group in one molecule (hereinafter, also referred to as “compound A”), and having a weight average molecular weight of 10,000 to 500, Preferably, it contains an epoxy group-containing polymer in the range of 000.

Among them, the thermosetting binder resin preferably contains both the epoxy resin (B1-a) and the epoxy group-containing copolymer (B1-b). (B1-a) Epoxy resin As the epoxy resin (B1-a), 2 per molecule
It is preferable to have at least two epoxy groups, for example, phenol novolak epoxy resin, cresol novolak epoxy resin, bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol AD epoxy resin, alicyclic epoxy resin, etc. No.

Of these epoxy resins, room temperature (25
° C) to 200 ° C for 1 minute to 2 hours.
It is preferable that the resin be cured by heating for 4 hours.
10 minutes to 12 hours at a heating temperature in the range of
It is more preferable that the resin be cured by heating for a long time. By heating and curing under such conditions, productivity is improved and the influence of heating on the substrate and the like is reduced.

The weight average molecular weight of the epoxy resin (B1-a) is preferably in the range of 300 to 5,000, more preferably in the range of 400 to 2,000. When the weight average molecular weight is in such a range, the balance between mechanical strength after heat curing of the conductive paste composition and productivity can be further improved. If the weight average molecular weight of the epoxy resin is less than 300, the mechanical strength after heat curing may be poor. On the other hand, when the weight average molecular weight exceeds 5,000, it takes time to uniformly dissolve in preparing the conductive paste composition, which may lower productivity.

The amount of the epoxy resin (B1-a) added is preferably in the range of 1 to 20 parts by weight, and more preferably 5 to 15 parts by weight, based on 100 parts by weight of the composite particles (A). More preferably, the value is within the range. When the amount of the epoxy resin (B1-a) is less than 1 part by weight,
The mechanical strength of the conductive paste composition after heat curing may be insufficient, and if the amount of the epoxy resin (B1-a) exceeds 20 parts by weight, the conductivity of the conductive paste composition is significantly reduced. May be.

(B1-b) Epoxy Group-Containing Polymer The epoxy group-containing polymer (B1-b) includes a unit derived from a compound (P) having an ethylenic double bond and an epoxy group in one molecule. The type of the polymer is not particularly limited as long as the polymer has a specific weight average molecular weight. Such an epoxy group-containing polymer (B1-b)
Is preferably a homopolymer of the compound (P) or a copolymer of the compound (P) and a monomer other than the compound (P).

Examples of the compound (P) include epoxy group-containing (meth) acrylates and epoxy group-containing vinyl compounds. As the epoxy group-containing (meth) acrylate, glycidyl (meth) acrylate, α-ethyl glycidyl (meth) acrylate, α-
Glycidyl n-propyl (meth) acrylate, α-n-
Glycidyl butyl (meth) acrylate, 3,4-epoxybutyl (meth) acrylate, 3,4-epoxyheptyl (meth) acrylate, α-ethyl-6,7-epoxyheptyl (meth) acrylate, and the like are included.

Examples of the epoxy group-containing vinyl compound include allyl glycidyl ether, vinyl glycidyl ether,
Examples thereof include o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether, p-vinylbenzyl glycidyl ether, and 3-vinylcyclohexene oxide. These can be used alone or in combination of two or more.

Among these epoxy group-containing monomers, glycidyl (meth) acrylate and glycidyl α-ethyl (meth) acrylate are particularly preferred. The structural unit derived from the compound (P) as described above is present in the epoxy group-containing polymer (B1-b) in an amount of preferably 10 to 100% by weight, more preferably 20 to 100% by weight. Is desirable.

When the content of the structural unit derived from the compound (P) is less than 10% by weight, the reactivity with the thermosetting resin may be significantly reduced. Examples of the epoxy group-containing polymer (B1-b) include a compound (P), a vinyl group-containing compound containing no epoxy group other than the compound (P), a (meth) acrylamide compound, and a (meth) acrylate. A homopolymer or a copolymer of two or more kinds of such monomers can also be used.

Examples of such a vinyl group-containing compound containing no epoxy group include hydroxystyrene, isopropenylphenol, styrene, α-methylstyrene, p-methylstyrene, chlorostyrene and p-methylstyrene.
Examples include methoxystyrene, vinylpyrrolidone, vinylcaprolactam, acrylonitrile, methacrylonitrile and the like.

As the (meth) acrylamide compound,
For example, acrylamide, methacrylamide, N, N
-Dimethylacrylamide and the like. further,
Examples of the (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, hydroxyethyl (meth) acrylate, phenyl (meth) acrylate, Examples include benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, and tricyclodecanyl (meth) acrylate.

Of these, styrene, acrylonitrile, hydroxystyrene, methyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate are particularly preferred. The weight average molecular weight of the epoxy group-containing polymer (B1-b) is preferably in the range of 10,000 to 500,000, more preferably 20,000.
00 to 400,000, particularly preferably 30,000 to
Desirably, the value is in the range of 300,000. When the weight average molecular weight of the epoxy group-containing polymer (B1-b) is in such a range, the conductive paste composition will have better balance between prevention of dripping during heating and applicability.

When the weight-average molecular weight of the epoxy group-containing polymer (B1-b) is less than 10,000, the viscosity at the time of heating and curing is sharply reduced, and sufficient dripping prevention cannot be obtained. May have poor strength. On the other hand, when the weight average molecular weight exceeds 500,000, the viscosity of the conductive paste composition excessively increases, and the coatability may decrease.

The method for producing the epoxy group-containing polymer (B1-b) is not particularly limited.
It can be obtained by adding a radical generator and radically polymerizing the compound (P) and, if necessary, the other monomer. Such radical generators include, for example, diacyl peroxides, ketone peroxides, hydroperoxides, dialkyl peroxides, peroxyesters, azo compounds, persulfates alone or in combination of two or more. They can be used in combination. More specifically, for example, benzoyl peroxide, lauryl peroxide, 2,2'-azobisisobutyronitrilo, 4,4'-azobis (4-cyanovaleric acid) and the like can be mentioned.

It is also preferable to use an inorganic reducing agent such as sodium hydrogen sulfite and sodium pyrosulfite, and an organic reducing agent such as cobalt naphthenate and dimethylaniline, if necessary. By using such a combination, the radical reaction can be performed in a shorter time. Further, the iodine-containing fluorine compound may be used alone or in combination with the organic peroxide, azo compound or persulfate.

The amount of the radical generator is, for example, based on 100 parts by weight of the monomer containing the compound (P).
The value is preferably in the range of 0.1 to 10 parts by weight. It is also preferable to add a chain transfer agent when producing the epoxy group-containing polymer (B1-b). By using a chain transfer agent, adjustment of the weight average molecular weight of the epoxy group-containing polymer (B1-b) becomes easier.

Examples of such a chain transfer agent include halogenated hydrocarbons such as carbon tetrachloride, chloroform, and carbon tetrabromide, n-hexyl mercaptan, and n-hexyl mercaptan.
-Octyl mercaptan, n-dodecyl mercaptan,
t-dodecyl mercaptan, thioglycols, mercaptans such as thiopropionic acid, etc.
-Methylstyrene dimer and the like.

The amount of the epoxy group-containing polymer (B1-b) to be added is, for example, preferably in the range of 1 to 15 parts by weight based on 100 parts by weight of the composite particles (A). Preferably, the value is in the range of 2 to 10 parts by weight with respect to 100 parts by weight of the composite particles (A). When the addition amount is in such a range, it is possible to prevent dripping at the time of heat curing in the conductive paste composition and to further improve the balance between the conductivity and the conductivity.

If the amount of the epoxy group-containing polymer (B1-b) is less than 1 part by weight, the conductive paste composition may not have the effect of preventing dripping during heat curing. Further, the epoxy group-containing polymer (B1-b)
When the addition amount exceeds 15 parts by weight, the addition amount of the composite particles may be relatively reduced and the conductivity may be reduced. (B2) Binder resin (fired type) Examples of the fired type binder resin (B2) include (meth) acrylic resin, hydroxystyrene resin,
Novolak resins, polyester resins, and the like.
Among them, the following monomer (M1) and monomer (M2)
And an acrylic resin such as a copolymer thereof.

Examples of the monomer (M1) include carboxyl group-containing monomers such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, succinic acid, crotonic acid, itaconic acid, citraconic acid, mesaconic acid, and cinnamic acid. 2-hydroxyethyl (meth) acrylate,
2-hydroxypropyl (meth) acrylate, (meth)
Examples include hydroxyl group-containing monomers such as 3-hydroxypropyl acrylate; and phenolic hydroxyl group-containing monomers such as o-hydroxystyrene, m-hydroxystyrene, and p-hydroxystyrene.

Examples of the monomer (M2) include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, benzyl (meth) acrylate, glycidyl (meth) acrylate, and dicyclopentane. Monomers such as nil (meth) acrylate (M
(Meth) acrylic esters other than 1); styrene,
aromatic vinyl monomers such as α-methylstyrene;
Monomers that can be copolymerized with the monomer (M1) represented by conjugated dienes such as butadiene and isoprene can be exemplified.

The weight average molecular weight of the binder resin (B2) is preferably in the range of 10,000 to 1,000,000, more preferably 20,000 to 1,000,000.
500,000, particularly preferably 30,000-30
It is desirable that the value be in the range of 0000. When the weight average molecular weight is in such a range, the balance between prevention of dripping after printing of the conductive paste and applicability can be improved.

When the weight average molecular weight of the binder resin (B2) is less than 10,000, sufficient sagging prevention may not be obtained after printing the conductive paste. On the other hand, when the weight average molecular weight exceeds 1,000,000, the viscosity of the conductive paste composition excessively increases, and the coatability may decrease. The method for producing the binder resin (B2) is not particularly limited, but the monomer is polymerized using a radical generator or a chain transfer agent similar to the epoxy group-containing polymer (B1-b). Can be obtained.

The amount of the binder resin (B2) added is
For example, 1 to 100 parts by weight of the composite particles (A)
The value is preferably in the range of 30 parts by weight, more preferably in the range of 2 to 15 parts by weight. When the addition amount is within such a range, the balance between the printability of the conductive paste and the conductivity can be further improved.

When the amount of the binder resin (B2) added is 1
When the amount is less than the weight part, the conductive paste may not be uniformly applied. On the other hand, when the addition amount of the binder resin (B2) exceeds 30 parts by weight, organic residues may be generated at the time of binder firing, and the conductivity may be reduced. (C) Additive The conductive paste composition according to the present invention further includes a curing agent, a glass powder, a coupling agent, a polymer additive, a reactive diluent, a polymerization inhibitor, Auxiliaries, leveling agents, wettability improvers, surfactants, plasticizers, ultraviolet absorbers, antioxidants, antistatic agents, inorganic fillers, fungicides, humectants, dye dissolving agents, buffer solutions, chelates And a flame retardant. These additives can be used alone or in combination of two or more.

(C-1) Curing Agent The curing agent (C-1) is preferably added to cure the binder resin (B1). The type of such a curing agent is not particularly limited, and examples thereof include amines, dicyandiamide, dibasic acid dihydrazide, and imidazoles as epoxy resin curing agents.

By adding such a curing agent,
The thermosetting of the epoxy resin can be performed efficiently. The amount of the curing agent is not particularly limited. For example, the amount of the curing agent is in the range of 1 to 30 parts by weight based on 100 parts by weight of the binder resin (B1). Is preferred.

When the amount of the curing agent is less than 1 part by weight,
Curability to epoxy resin may be significantly reduced. On the other hand, if the amount of the curing agent exceeds 30 parts by weight, it becomes difficult to control the reactivity, and the storage stability of the epoxy resin may be reduced. The amount of the curing agent used is 0.1% with respect to 100 parts by weight of the composite particles (A).
It is preferably in the range of 10 to 10 parts by weight.

The thermosetting type binder resin (C)
When using 1), it is also preferable to use a curing accelerator, if necessary. The type of such a curing accelerator is not particularly limited, and examples thereof include organic boron, tertiary amines, imidazole, and salts thereof. These are particularly preferred as curing accelerators for epoxy resins.

When such a curing accelerator is used, its amount is preferably 0.1 to 10 parts by weight, more preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the binder resin.
It is desirable to be within the range of 5 parts by weight. The addition amount of the curing accelerator is preferably in the range of 0.1 to 5 parts by weight based on 100 parts by weight of the composite particles (A).

(C-2) Coupling Agent The conductive paste composition of the present invention may contain a coupling agent. By adding the coupling agent, the applicability to the base material is improved, and the moisture resistance is significantly improved. Therefore, excellent adhesion and the like can be obtained over a long period of time.

As such a coupling agent, a silane coupling agent, an aluminum coupling agent,
Examples include at least one coupling agent selected from the group consisting of titanate-based coupling agents and zirconate-based coupling agents. Among these coupling agents, it is preferable to add a silane coupling agent since an excellent effect of improving moisture resistance and the like can be obtained by adding a relatively small amount.

The type of the silane coupling agent is not particularly limited, either.
-Aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropyldimethylmethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane , N
-Decyltrimethoxysilane and the like. These can be used alone or in combination of two or more.

The addition amount of the coupling agent is preferably 0.1 to 1 with respect to 100 parts by weight of binder resin (B).
0 parts by weight, more preferably in the range of 0.5 to 5 parts by weight. If the amount is less than 0.1 part by weight, the effect of addition may not be exhibited. On the other hand, when the addition amount exceeds 10 parts by weight, self-condensation may occur, and the storage stability of the conductive paste composition may decrease.

Method for Using Conductive Paste Composition The method for using the conductive paste composition of the present invention includes the following steps. (1) Step of preparing a conductive paste composition (may be referred to as a first step) (2) Step of applying a conductive paste composition onto a substrate (may be referred to as a second step) (3) Step of hardening or baking the conductive paste composition by heating (sometimes referred to as a third step) (1) First step In the first step, the composite particles (A) and the binder resin ( B)
And, if necessary, the additive (C) is uniformly mixed and stirred using a mixer or the like to prepare a conductive paste composition material.

The mixer used in the first step includes a ball mill, a propeller mixer, a high shear mixer, a stirring and defoaming device, a three roll, a V blender, a kneader, a microfluidizer, and the like. In addition, when mixing the materials constituting the conductive paste composition, the temperature in the mixer may increase. In that case, it is preferable to keep the temperature within, for example, 60 ° C. by using a cooling device or the like. When the temperature inside the mixer exceeds 60 ° C,
Part of the binder resin may react and cure.

In the first step, the viscosity of the conductive paste composition is 1,000 to 1,000,000 mP.
It is preferably adjusted to a value within the range of a · s (measurement temperature 25 ° C., the same applies hereinafter). When the viscosity of the conductive paste composition is less than 1,000 mPa · s, the composite particles may be settled or may be easily dripped when applied. On the other hand, the viscosity is 1,000,000 mPa ·
If it exceeds s, it may be difficult to apply the composition uniformly.

Further, the viscosity of the conductive paste composition is as follows:
More preferably, 10,000 to 600,000 mPa
S, particularly preferably 30,000 to 400,000 m
It is desirable that the value be in the range of Pa · s. When the viscosity is in such a range, the applicability of the conductive paste and the dispersibility of the composite particles become better. (2) Second Step The second step is a step of applying (printing) the conductive paste composition onto the base material using, for example, an applicator. At this time, a magnet is placed under the substrate to be coated.

Here, preferable coating machines include a screen printing machine, a gravure coating machine, a roll coating machine and the like. When a screen printing machine is used, for example, it is preferable to use a plate having a thickness of 30 to 200 μm, a hole diameter or a wiring width of 30 to 200 μm as a plate material, such as SUS, Ni-Co, or the like. . The magnet, Nd-Fe-B-based, Sm-Co system or the like rare earth _{magnet, BaO · xFe 2 O 3,} SrO · xFe 2 O 3 or the like ferrite magnets, Fe-Co-Ni-Al -Cu -based, etc. Alnico magnets. Further, an electromagnet may be used in addition to the permanent magnet.

The substrate on which the conductive paste is applied is not particularly limited, but may be a copper foil, a gold foil, a silver foil, a platinum foil,
A conductive material such as a nickel foil, a stainless steel foil, or an aluminum foil may be used, an insulating substrate such as a polyimide resin, a phenol resin, a bismaleimide / triazine resin, a ceramic substrate, a glass substrate, or a Si wafer. A semiconductor substrate may be used.

(3) Third Step In the third step, the conductive paste composition is cured or baked by heating, for example, in an oven or the like, to form conductive portions such as bumps and circuit board patterns. It is a process. When thermosetting the conductive paste composition, it is preferable to use the thermosetting binder resin (B1). The curing conditions are not particularly limited, and the epoxy resin (B1) contained in the binder resin (B1) may be used.
-A) and / or an epoxy group-containing polymer (B1-
Any temperature may be used as long as b) cures. For example, the heating temperature is preferably in the range of room temperature (about 25 ° C) to 200 ° C for a heating time of 1 minute to 24 hours, more preferably 100
The composition can be cured at a heating temperature in the range of from 0 to 180 ° C for a heating time of from 10 minutes to 12 hours.

When sintering the conductive paste composition, it is preferable to use the binder resin (B2). The sintering conditions are not particularly limited as long as the binder resin (B2) is sintered.
At a heating temperature of 1 minute to 6 hours. When heating or curing or sintering the conductive paste composition,
Examples of the heating method include a method of heating with an oven, an infrared lamp, a hot plate, or the like.

Since the conductive paste composition according to the present invention contains the composite particles (A) comprising a conductive component and a ferromagnetic component, even if the content of the ferromagnetic component is high, the conductive paste composition can be used. An increase in the resistivity of the conductive portion obtained from the composition can be suppressed, and a conductive portion having excellent conductivity can be formed. In addition, since it is excellent in magnetic sensitivity, the use of a magnet at the time of application prevents the scale of the plate at the time of paste application,
It becomes possible to form bumps or wiring electrodes by high-definition printing.

[0069]

The conductive paste composition according to the present invention comprises:
Since composite particles having an excellent balance between the conductive component and the magnetic component can be used, the magnetic particles have excellent magnetic sensitivity and low resistance. Also, it is excellent in preventing clogging of the plate when applying the paste. Therefore, it is suitable for forming bumps or wiring electrodes, and is also suitable for high-definition printing.

[0070]

EXAMPLES Examples of the present invention will be described below, but the scope of the present invention is not limited to the description of these examples. In the examples, the amounts of the respective components mean parts by weight unless otherwise specified.

[0071]

[Polymerization Example 1] [Thermosetting binder resin (A-
1) Production of (Epoxy Group-Containing Polymer)]
Glycidyl methacrylate (abbreviated as GMA) 25 g
10 g of acrylonitrile (abbreviated as AN),
15 g of methyl methacrylate (abbreviated as MMA)
And 50 g of dioxane (abbreviated as DOX) were mixed to obtain a uniform reaction raw material solution.

After bubbling nitrogen for 30 minutes into the reaction raw material solution, 2,2 as a polymerization initiator was used.
1.9 g of azobisisobutyronitrile (abbreviated as AIBN) were added. The temperature inside the reaction vessel was raised to 70 ° C. while continuing nitrogen bubbling. The polymerization reaction was continued for 7 hours at the same temperature. The obtained reaction solution and a large amount of hexane were mixed to coagulate the polymer, and then the polymer was collected and redissolved in dioxane. The operation of coagulation with hexane and re-dissolving with dioxane was repeated five times to remove unreacted monomers.
Next, dioxane was scattered under the condition of 70 ° C. and reduced pressure,
A white epoxy group-containing polymer was obtained. The weight average molecular weight of this polymer was measured using GPC (gel permeation chromatography) and found to be 110,000.
Met. This polymer is designated as A-1.

[0073]

[Polymerization Example 2] [Firing type binder resin (A-2)
(Production of (Acrylic Resin)) In a reaction vessel, 20 g of 2-hydroxyethyl methacrylate, 80 g of methyl methacrylate, and 50 g of dioxane were mixed to obtain a uniform reaction raw material solution. After bubbling nitrogen for 30 minutes with respect to this reaction raw material solution, 1.9 g of 2,2-azobisisobutyronitrile as a polymerization initiator and t-dodecyl mercaptan (D- SH). 0.5 g was added.

Next, polymerization was carried out in the same manner as in Polymerization Example 1, and unreacted monomers were removed to obtain a white acrylic resin. The average weight molecular weight of this polymer measured by GPC was 80,000. This polymer is designated as A-2.

[0075]

Example 1 [Conductive paste composition using thermosetting binder] (1) Preparation of conductive paste composition Epicoat 1 which is an epoxy resin as a thermosetting resin
8 parts by weight of 004 (weight average molecular weight: 1600, manufactured by Yuka Shell Epoxy Co., Ltd.) and 3 parts by weight of the epoxy group-containing radical polymer (A-1) obtained in Polymerization Example 1 were added to 10 parts by weight of butyl cellosolve acetate To make a uniform resin solution.

Composite particles containing silver as a conductive component and nickel as a ferromagnetic component (manufactured by Nisshin Steel Co., Ltd .: 40% by weight of silver as a conductive component, and 100 parts by weight containing nickel in a proportion of 60% by weight, having a spherical shape and a particle size of 5 μm), 210 parts by weight as a silane coupling agent (manufactured by Toray Dow Corning Co., Ltd.), and imidazole as an epoxy curing agent 2P4MHZ (Shikoku Chemical Industry Co., Ltd.)
1.5 parts by weight). These conductive paste composition materials were kneaded for one hour using three rolls to obtain a conductive paste composition. The viscosity of this conductive paste composition was 100,000 mPa · s.

(2) Application of conductive paste composition An Sm-Co-based magnet (1,000 gauss) was placed under a copper foil, and the prepared conductive paste was applied to a metal plate (thickness 125
.mu.m, hole diameter 150 .mu.m) on a copper foil with a screen printer. The bump was dried at 100 ° C. for 10 minutes. At this time, the printed state was observed using an optical microscope.

As a result, the conductive paste composition was printed in a predetermined test pattern shape. Also, after printing,
When the metal plate was observed, clogging by the conductive paste composition was not confirmed. (3) Heat Curing of Conductive Paste Composition Next, a bump made of the conductive paste composition was heated and cured using an oven at 150 ° C. for 30 minutes.

The cured bumps were observed using an optical microscope. As a result, nobody or blur was observed at all. The cured bump shape was observed using a scanning electron microscope. As a result, a height of 160 μm and a diameter of 15
A bump shape having a high aspect ratio of 0 μm was obtained. When the resistivity of the cured coating film was measured using a resistivity meter, it was confirmed that the cured film exhibited a good conductivity of 0.5 mΩ · cm.

[0080]

Example 2 [Conductive paste composition using thermosetting type binder] Instead of the composite particles used in Example 1, composite particles containing silver as a conductive component and nickel as a ferromagnetic component ( Tokuriki Chemical Laboratory Co., Ltd .:
It contains 40% by weight of silver as a conductive component and 60% by weight of nickel as a ferromagnetic component.
A conductive paste composition was prepared in the same manner as in Example 1 except that 100 parts by weight (0 μm, film thickness 2 μm) was used. The viscosity of this conductive paste composition is 80,000 mP
a · s.

Further, in the same manner as in Example 1, the obtained conductive paste composition was screen-printed in a test pattern shape. The bump was dried at 100 ° C. for 10 minutes. At this time, the printed state was observed using an optical microscope. As a result, the conductive paste composition was printed in a predetermined test pattern shape. When the metal plate was observed after printing, clogging with the conductive paste composition was not confirmed.

Next, in the same manner as in Example 1, the bump made of the conductive paste composition was heated and cured in an oven at 150 ° C. for 30 minutes. The cured bump was observed using an optical microscope. As a result, nobody or blur was observed at all. When the bump shape after curing was observed using a scanning electron microscope,
A bump shape having a height of 170 μm and a diameter of 150 μm and a high aspect ratio was obtained.

When the resistivity of the cured coating film was measured using a resistivity meter, it was confirmed that the cured film exhibited a good conductivity of 0.1 mΩ · cm.

[0084]

Comparative Example 1 [Conductive paste composition using thermosetting binder] Instead of the composite particles used in Example 1, flaky silver powder AY6080 which is conductive particles
(Average particle size 1 μm, manufactured by Tanaka Kikinzoku Kogyo KK) 40 parts by weight and spherical nickel powder # 110 which is ferromagnetic particles
(Average particle size: 1.4 μm, Nikko Fine Products Co., Ltd.)
The conductive paste composition was obtained in the same manner as in Example 1 except for using 60 parts by weight of the conductive paste composition. The viscosity of this conductive paste composition was 110,000 mPa · s.

Further, in the same manner as in Example 1, the obtained conductive paste composition was screen-printed in a test pattern shape. The bump was dried at 100 ° C. for 10 minutes. At this time, the printed state was observed using an optical microscope. As a result, the conductive paste composition was printed in a predetermined test pattern shape. When the metal plate was observed after printing, clogging with the conductive paste composition was not confirmed.

Next, in the same manner as in Example 1, the bump made of the conductive paste composition was cured by heating in an oven at 150 ° C. for 30 minutes. The cured bump was observed using an optical microscope. As a result, nobody or blur was observed. When the bump shape after curing was observed using a scanning electron microscope, a bump shape having a height of 150 μm and a diameter of 150 μm and an aspect ratio was obtained.

When the resistivity of the cured coating film was measured using a resistivity meter, it was 10 mΩ · cm, which was higher than those of Examples 1 and 2.

[0088]

Example 3 [Conductive paste composition using sintering type binder] The acrylic resin (A
-2) 10 parts by weight were dissolved in 20 parts by weight of ethyl lactate (solvent) to obtain a uniform resin solution. To this resin solution, 100 parts by weight of composite particles (manufactured by Nissin Steel Co., Ltd.) similar to the composite particles used in Example 1 were added. And
These conductive paste compositions were kneaded for 20 minutes using three rolls to obtain a conductive paste composition. The viscosity of the conductive paste composition is 120,000 mPa.
-It was s.

Next, an Sm—Co-based magnet (2,000 gauss) was placed under the Si wafer, and the prepared conductive paste composition was placed on a metal plate (thickness 30 μm, wiring width 50 μm).
m) on a Si wafer with a screen printer. When the metal plate was observed after printing, clogging with the conductive paste composition was not confirmed.

Next, this wiring is heated at 400 ° C.
After heating under the condition of 0 minute, it was baked at 450 ° C. for 30 minutes in hydrogen. The pattern shape after firing was observed using a scanning electron microscope. As a result, nobody or blur was observed. In addition, a wiring shape having a height of 10 μm and a width of 40 μm was obtained. In addition, when the resistivity of the fired coating film was measured using a resistivity meter, it was confirmed that the film showed good conductivity of 10 μΩ · cm.

[0091]

[Example 4] [Conductive paste composition using calcination type binder] Instead of the composite particles used in Example 3, composite particles (manufactured by Tokurika Chemical Laboratory Co., Ltd.) used in Example 2 were used. A conductive paste composition was prepared in the same manner as in Example 3 except that parts by weight were used. The viscosity of this conductive paste composition was 130,000 mPa · s.

Further, in the same manner as in Example 3, the obtained conductive paste composition was screen-printed in a test pattern shape. When the metal plate was observed after printing, clogging with the conductive paste composition was not confirmed.
Next, the wiring was heated in air at 400 ° C. for 30 minutes, and then fired in hydrogen at 450 ° C. for 30 minutes.

The pattern shape after firing was observed using a scanning electron microscope. As a result, nobody or blur was observed at all. Further, a wiring shape having a height of 11 μm and a width of 42 μm was obtained. Further, the resistivity of the fired coating film was measured using a resistivity meter, and it was confirmed that the film showed good conductivity of 5 μΩ · cm.

[0094]

Comparative Example 2 [Conductive paste composition using binder of fired type] Instead of composite particles used in Example 3, scaly silver powder AY6080 which is conductive particles
(Average particle size 1 μm, manufactured by Tanaka Kikinzoku Kogyo KK) 40 parts by weight and spherical nickel powder # 110 which is ferromagnetic particles
(Average particle size: 1.4 μm, Nikko Fine Products Co., Ltd.)
Except for using 60 parts by weight), a conductive paste composition was obtained in the same manner as in Example 3. The viscosity of this conductive paste composition was 120,000 mPa · s.

Next, an Sm-Co-based magnet (2,000 gauss) was placed under the Si wafer, and the prepared conductive paste composition was placed on a metal plate (thickness 30 μm, wiring width 50 μm).
m) on a Si wafer with a screen printer. When the metal plate was observed after printing, clogging with the conductive paste composition was not confirmed.

Next, this wiring is heated at 400 ° C.
After heating under the condition of 0 minutes, it was baked at 450 ° C. for 30 minutes in hydrogen. The pattern shape after firing was observed using a scanning electron microscope. As a result, nobody or blur was observed. In addition, a wiring shape having a height of 15 μm and a width of 55 μm was obtained.

When the resistivity of the fired coating film was measured using a resistivity meter, it was 80 μΩ · cm, which was higher than those of Examples 3 and 4.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05K 3/12 610 H05K 3/12 610B (72) Inventor Satomi Hasegawa 2- 24-11 Tsukiji, Chuo-ku, Tokyo No. F-term in JSR Co., Ltd. (reference) 4J002 BC121 BG011 BG021 BG041 BG051 CD001 CD021 CD051 CD171 CD191 DA076 DA087 DA116 DE077 DE097 DE117 FD116 FD140 FD207 5E343 AA02 BB22 BB23 BB24 BB25 BB52 BB05 BB25 BB52 BB52 BB25 BB52 BB52 BB25 BB52 BB52 BB52 BB05

Claims (4)

[Claims] 1. A conductive paste composition comprising: (A) composite particles containing a conductive component and a ferromagnetic component; and (B) a binder resin. 2. The method according to claim 1, wherein the ferromagnetic component is the composite particle (A).
2. The conductive paste composition according to claim 1, wherein the conductive paste composition is contained at a ratio of 5 to 70% by weight based on the total weight of the composite particles (A). 3. 3. The conductive paste composition according to claim 1, wherein the composite particles (A) have a surface of the ferromagnetic component coated with the conductive component. 4. The method according to claim 1, wherein the conductive paste composition is applied to a base on which a magnet is provided below the base and used to form a conductive part on the base. The conductive paste composition according to claim 1.