JPH1021741A - Anisotropic conductive composition and film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an anisotropic conductive composition and film with quick connection capability, high conductivity, high environmental durability, fine pitch connection capability, and high withstand voltage. SOLUTION: An anisotropic conductive composition and film contain 0.5-250 pts.wt. epoxy resin to 1 pts.wt. copper alloy powder represented by general formula, Agx Cu1-x (0.001<=X<=0.6, X is atomic ratio.), in which silver concentration is high on the surface and 0.1-800ppm at least one element selected from Si and Ti is contained, and 5-250 pts.wt. encapsulated imidazole derivative epoxy compound to 100 pts.wt. epoxy resin as an curing agent. Quick connection is made possible, conductivity and environmental durability are enhanced, and insulation at fine pitch is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The anisotropic conductive composition and film of the present invention include liquid crystal panels, plasma displays,
TAB connection to L display, COG connection of LSI bare chip, C on LSI bare chip on printed circuit board
It can be used for OB connection, COF connection, connection of a flexible substrate to a display panel, and connection between a flexible substrate and a rigid substrate. In particular, it is effective for fine pitch applications such as liquid crystal televisions, mobile phones, liquid crystal cameras, watches, word processors, copiers, telephones, personal computers, plasma displays, EL panels, and calculators.

[0002]

2. Description of the Related Art Until now, many anisotropic conductive films have been used for connection of a driver IC for a liquid crystal or the like. The size of the liquid crystal itself has been reduced, and the fine pitch of the connection terminals has been rapidly progressing. Although a larger number of anisotropic conductive films have been disclosed in the related art, see, for example, Japanese Patent Application Laid-Open No. H7-1970.
No. 01, Japanese Patent Application Laid-Open No. H4-2242010, an anisotropic conductive film using conductive particles obtained by plating metal on a resin ball, and metal powder such as nickel powder, solder powder, and gold-plated nickel powder. An anisotropic conductive film is disclosed (for example, Japanese Patent Application Laid-Open No. 61-55809).
No.).

An anisotropic conductive film is a film in which conductive particles are dispersed in an organic binder. The film is bonded to electrodes or terminals on a substrate to be connected in advance to form a substrate to be connected or an LSI to be connected. After the alignment, the organic binder is dried or heated and cured by pressing and heating. At this time, only the conductive particles sandwiched between the electrodes are deformed to have conductivity only in the direction between the electrodes, and the adjacent electrodes are kept insulative. It has been used for TAB connection of driving ICs for panels such as liquid crystal, plasma display, and EL, connection of LSI bare chips, connection of flexible substrates to panels, and the like.

[0004]

The anisotropic conductive film which has been conventionally used has the following limitations. That is, in the case of ultra-fine pitch connection of 50 microns or less, the number of particles contributing to conduction is particularly reduced, and the connection resistance is extremely increased. For this reason, when the amount of the conductive powder is increased, the probability that the conductive powders are arranged side by side between adjacent electrodes increases, causing a problem of short circuit, and there is no fine pitch that satisfies both good connection resistance and insulation at the same time. is the current situation.

For example, in the case of a metal-plated resin powder, when the conductive powder is deformed by pressurization, not only the plating is peeled off and frequent insulation failure is caused, but also the conductive path is originally formed only by the plated metal layer. Therefore, it cannot be used for fine pitch connection. Metal powder has also been used because its conductivity is inherently higher than plating resin powder.
Originally, it has high specific resistance and cannot be used for fine pitch.
It is not satisfactory because of poor environmental resistance and increased connection resistance. Further, since nickel powder is hard, a pressure at the time of connection is required to be several tens kg / cm ² to 100 kg / cm ² , so that the substrate is greatly damaged and the glass substrate is damaged.

[0006] In the case of solder powder, the specific resistance among metal powders is about one digit higher than that of copper or silver, making it impossible to cope with fine pitch connection. In addition, since the melting point is low, a semi-molten state often occurs during heating connection. Was pulling, poor connection. In the case of gold-plated nickel powder, good plating resistance cannot be obtained at a fine pitch because the gold plating peels off under pressure and also depends on the resistance value of the nickel powder itself. Pressing force is required. In the case of silver powder, the insulating property between adjacent electrodes tends to decrease due to water absorption or the like, and it was impossible to cope with fine pitch connection.

For the purpose of preventing a short circuit between adjacent electrodes at a fine pitch, a method of further coating the surface of the above powder such as nickel powder, silver powder, metal plating resin powder with an insulating resin is disclosed. (For example, see JP-A-6-60
712, JP-A-7-90236, JP-A-7-90236
It is necessary to heat-melt the coated insulating resin by pressurizing and heating at the time of connection, so that the bonding time is too long, for example, several tens of seconds. It cannot be completely melted and removed from the surface of the conductive particles, and there is a problem of insufficient reliability.
Further, from the viewpoint of recent high productivity, it is not possible to meet a demand for performing pressurization and heating in a short time of several seconds.

On the other hand, the organic binder in which the conductive particles are dispersed is often a thermosetting type in which an epoxy resin is used from the viewpoint of adhesiveness. However, before the use of the anisotropic conductive composition or film, crosslinking of the epoxy is difficult. It is naturally preferable to keep the state as small as possible. However, depending on the curing agent, curing of the epoxy has often already progressed when the anisotropic conductive composition is used, resulting in poor adhesion to the substrate or poor conduction.

[0009]

In order to solve the above-mentioned problems, the present invention makes it possible to secure insulation by short-time connection, low-voltage connection, ultra-fine-pitch connection, and ultra-fine-pitch connection. An object of the present invention is to provide an anisotropic conductive composition and a film having good properties. That is, the present invention provides 0.5 to 200 parts by weight of epoxy resin and 1 part by weight of epoxy resin 100 parts by weight based on 1 part by weight of copper alloy powder having an average particle diameter of 2 to 15 microns having the following features (1) and (2). This is an anisotropic conductive composition containing 5 to 250 parts by weight of a microcapsule type imidazole derivative epoxy compound as a curing agent with respect to parts by weight. (1) General formula Ag _X Cu _1-X (0.001 ≦ x ≦ 0.
6, x is an atomic ratio), and the silver concentration on the surface of the powder is higher than the average silver concentration. (2) One or more components selected from Si and Ti are added in 0.1%.
Preferably, in the particle size distribution of the copper alloy powder, the powder having an average particle diameter of ± 2 μm is 30 to 100% by volume, and the content of oxygen is 1 to 10000 ppm.

The copper alloy powder used in the present invention has the general formula Ag
_X Cu _1-X (0.001 ≦ x ≦ 0.6, x is an atomic ratio), but since it is a conductive powder having high conductivity of both copper and silver, it has high conductivity at the time of connection, High conductivity can be maintained even if the number of particles at a fine pitch is reduced. In this case, when x exceeds 0.6, the silver component is large and migration between adjacent electrodes occurs, leading to a short circuit. When x is less than 0.001, oxidation resistance is insufficient and conduction resistance is significantly increased. Preferably, x is 0.0
1 to 0.4. Many electrodes or terminals of a substrate or a connected substrate mainly contain copper, and therefore have characteristics such as a small thermal expansion coefficient and a small change in connection resistance even in a test such as a heat cycle. Further, since the silver concentration on the surface of the copper alloy powder is higher than the average silver concentration, the copper alloy powder at the connection point with the electrode can be prevented from being oxidized and degraded, and the migration property of silver can be prevented. In addition, since a copper component is present on the powder surface and an oxygen compound (hydroxide or oxide) is formed, wettability with epoxy on a clean metal surface can be improved, and as a result, dispersibility can be improved. Can be improved.

The silver concentration on the powder surface is 1.5 times the average silver concentration.
It is preferable that the silver concentration be higher than twice, but the silver concentration on the surface does not need to be high until the silver is completely covered, for example, 1.5 to 100 times. The silver concentration on the powder surface is defined as XPS (X
It is a value (Ag / (Cu + Ag)) calculated by using a correction coefficient from the area values of Cu ₂ p and Ag ₃ d measured by a line photoelectron spectrometer; XSAM800 (manufactured by KRATOS). Average silver concentration, average copper concentration (Ag / (A
g + Cu)) and (Cu / (Ag + Cu)) are obtained by dissolving a copper alloy powder in a concentrated nitric acid solution, and applying an ICP (high frequency inductively coupled plasma analyzer (manufactured by Seiko Denshi Kogyo; JY38P).
It measured using 2).

Further, the copper alloy powder used in the present invention is S
i, contains one or more components selected from Ti,
It is preferably present on the powder surface. Si and Ti function as oxygen trapping agents in a severe oxidizing environment, and can improve the environmental resistance of the copper alloy powder. When present on the powder surface, it is more preferable to coordinate the silane coupling agent and the titanium coupling agent on the surface of the copper alloy powder. By being present on the surface of the powder, even when the copper alloy powder is arranged between the adjacent electrodes, the effect of the coupling agent has an effect of preventing the copper alloy powder from directly contacting and preventing conduction. Further, the effect of the coupling agent can increase the wettability with the resin, sufficiently cover the surface of the copper alloy powder, and prevent the copper alloy powder from deteriorating due to water absorption.

[0013] Further, there is no formation of a thick coating layer on the surface such as an insulating resin coat, and further, sufficient insulation between conductive particles can be ensured without requiring a phenomenon such as melting and removing. . In other words, there is no need for complicated processing such as coating with an insulating resin, and there is no need to break the insulating coating resin by heating and melting at the time of pressure welding, and high productivity can be achieved in a short time.

The silane coupling agent is an organic silicon monomer having two or more different reactive groups in a molecule, and one of these reactive groups is an inorganic monomer such as glass, metal, or silicon. Reactive groups (methoxy, ethoxy, silanol, halide, alkoxide, acyloxy), which are chemically bonded to organic materials constituting various synthetic resins (for example, vinyl) Group, epoxy group, methacryl group, amino group, mercapto group, diamino group, aliphatic epoxy group), for example, vinyltrichlorosilane, vinyltriethoxysilane, γ-chloropropyltrimethoxysilane, γ-chloro Propylmethyldichlorosilane, γ
-Chloropropyldimethoxysilane, γ-chloropropylmethyldiethoxysilane, γ-aminopropyltriethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, N- (β-aminoethyl) -γ -Aminopropylmethyldimethoxysilane, γ
-Mercaptopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, alkoxysilane, chlorosilane, etc. Is preferred.

The titanium coupling agent includes an organic titanium compound. For example, R1-Ti- (R2)
3 (wherein R1 has 1 to 4 carbon atoms, preferably 1 to 4 carbon atoms)
The alkoxy group 3 and R2 are carboxylic acid esters having 2 to 20 carbon atoms, preferably 2 to 18 carbon atoms. For example, isopropyl triisosteayl titanate, isopropyl trioctanoyl titanate, isopropyl tris (dioctyl pyrophosphate) titanate,
Isopropyl (N-aminoethyl-aminoethyl) titanate, tetraoctylbis (ditridecylphosphate) titanate, tetra (2,2-diallyloxymethyl-1-butyl) bis (ditridecyl) phosphate titanate, bis (dioctylpyrophosphate) oxy Acetate titanate, bis (dioctyl pyrophosphate) ethylene titanate, isopropyl dimethacrylic isostearoyl titanate, isopropyl isostearoyl diacryl titanate, isopropyl tri (dioctyl phosphate) titanate, isopropyl tricumyl phenyl titanate, tetraisopropyl bis (dioctyl phosphate titanate) Is preferred.

When a coupling agent is used, the wettability between the copper alloy powder and the organic binder (particularly epoxy) is improved,
There is an advantage that the copper alloy powder does not exist in a bare state and the insulating property at a fine pitch can be maintained. Further, it is not necessary to melt such as an insulating resin coat, and connection can be made in a short time. Further, the adsorption of moisture to the copper alloy powder is inhibited, and the environmental resistance can be improved. When the coupling agent is applied to the surface, it is preferable to dissolve the coupling agent in a solvent or the like, disperse the copper alloy powder, and perform the surface treatment. The amounts of Si and Ti contained in the copper alloy powder were measured by dissolving the copper alloy powder in a concentrated nitric acid solution by ICP-mass. Si, Ti content is 0.1-800ppm
However, it is preferably 0.1 to 300 ppm. 8
If it exceeds 00 ppm, the conductivity itself is impaired.
If the amount is less than 0.1 ppm, the insulation at a fine pitch becomes insufficient.

The average particle size of the copper alloy powder is 2 to 15
Micron is preferable, and when it is less than 2 micron, the conductive particles sandwiched between the electrodes at the time of pressurization have the roughness level of the electrode surface, resulting in poor conductivity and poor environmental resistance. Fifteen
If the diameter exceeds micron, the number of conductive particles between the electrodes becomes insufficient and the connection resistance becomes unstable due to the fine pitch between the electrodes. Preferably the average particle size is from 2 to 10 microns.

In the copper alloy powder used in the present invention, it is preferable that the existence ratio of the powder having an average particle diameter of ± 2 μm or more is 30% or more, and the conductive powder effectively participates in conduction between the electrodes in many cases. Preferred to be present. However, it is preferable to have a particle size distribution in order to print the anisotropic conductive composition on the connection substrate or to form a uniform film of the anisotropic conductive film. The particle size distribution means that particles having an average particle diameter of ± 1 μm are present. For example, a particle having a volume ratio of 10% is preferable for preparing a coating film, and is preferable because it has thixotropy.

The average particle diameter used in the present invention refers to a laser diffraction type measuring apparatus RODOS SR type (SYMATETEC).
(HEROS & RODOS) and the volume integrated average particle diameter was used. The presence of the copper alloy powder within an average particle size of ± 1 μm is read by a volume integrated particle size distribution meter. Further, the copper alloy powder contains oxygen and oxygen in an amount of 1 to 10000.
ppm is preferable, and by including a certain amount of oxygen (oxygen as a hydroxide or oxygen as an oxide) on the surface, the wettability with the epoxy as a binder is improved over a clean metal surface. Thus, the dispersibility of the powder can be improved without deteriorating the properties of the powder. Also, when a coupling agent is used, it easily coordinates with a hydroxide or oxide on the surface. As for this oxygen, the copper component on the surface may be in an oxide or hydroxide state. When it exceeds 10,000 ppm, not only environmental resistance is deteriorated, but also curing of epoxy is accelerated and storage stability is deteriorated. The measurement of the oxygen content is performed by raising the temperature to 2000 ° C. using an oxygen / nitrogen analyzer (EMGA650; manufactured by Horiba, Ltd.). The oxygen content is preferably 1 to 3000 ppm.

The copper alloy powder used in the present invention is preferably produced by, for example, an inert gas atomizing method.
The inert gas atomization method preferably uses nitrogen, helium, hydrogen, argon, and a mixed gas thereof.For example, a method in which a silver or copper melt having such a composition is pulverized into fine particles by rapid collision with an inert gas and rapidly solidified. It is. As the shape, a spherical shape, a scale shape, a dendritic shape, and the like can be used.

The anisotropic conductive composition or film of the present invention contains 0.5 to 250 parts by weight of an epoxy resin with respect to 1 part by weight of a copper alloy powder. A type, bisphenol F type, bisphenol S type, phenol novolak type, cresol novolak type, alkyl polyhydric phenol type, phenyl glycidyl ether type, polyfunctional polyether type, brominated phenol novolak type, modified bisphenol S type, diglycidyl aniline An epoxy resin such as a mold, a diglycidyl orthotoluidine type, a urethane modified, a rubber modified, a silicone modified, and a chain modified type can be used. Particularly, an epoxy resin which is liquid at room temperature is preferable.
By using epoxy resin as the organic binder, the adhesion to the connection board can be improved, and the copper alloy powder has a small amount of copper component on the surface, and the copper component is oxygen-containing. In addition, there is a synergistic effect that the wettability with epoxy can be further improved compared to a clean metal surface. If the amount exceeds 250 parts by weight, the number of copper alloy particles is too small and the connection resistance increases. If the amount is less than 0.5 parts by weight, the copper alloy powders come into contact with each other and the insulation property is reduced.

The anisotropic conductive composition and film of the present invention contain 0.5 to 250 parts by weight of a microcapsule type imidazole derivative epoxy compound as a curing agent with respect to 100 parts by weight of epoxy resin. As a microcapsule-type imidazole derivative epoxy compound, the reaction product of the imidazole derivative and the epoxy compound is pulverized into fine powders, and the resulting product is further reacted with an isocyanate compound and the like. It is a thing that raised the character.

The use of the microcapsule-type imidazole derivative epoxy compound can improve the storage stability of the anisotropic conductive composition and the film. Also, pressurization,
The point is that uniform curing can be expected in a short time of only a few seconds of heat bonding. The reaction does not proceed gradually during heating, but the diffusion into the inside of the film proceeds within a few seconds, and uniform curing can be expected. Further, since the copper alloy powder used in the present invention easily conducts heat, there is also an advantage that heat can be easily transmitted to the microcapsule type hardener dispersed in the organic binder, and uniform hardening can be promoted. That is, sufficient curability can be obtained even in a short time of several seconds.

Further, by using the copper alloy powder of the present invention, the copper alloy powder can break through the isocyanate coating of the microcapsule when deformed under pressure, and the curing can be accelerated rapidly. The microcapsule-type imidazole derivative epoxy compound is stable at room temperature, melts at a temperature of several tens of degrees, and remarkably promotes solidification of the epoxy near a compression temperature. Examples of the imidazole derivative at this time include, for example, imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole,
2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole,
-Benzyl-2-ethylimidazole, 1-benzyl-2
-Ethyl-5-methylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl4,5-dihydroxymethylimidazole and the like. Examples of the epoxy compound include glycidyl ether type epoxy resins such as bisphenol A, bisphenol F, phenol novolak, and brominated bisphenol A, diglycidyl dimer acid, and diglycidyl phthalate. The amount of the microcapsule type imidazole derivative epoxy compound curing agent is preferably 1 to 200 parts by weight based on 100 parts by weight of the epoxy resin. More preferably, it is 1 to 150 parts by weight. Also, as the particle size of the microcapsule type curing agent,
An average particle size of 1 to 10 microns is preferred. It is 1
If the thickness exceeds 0 μm, the thickness of the anisotropic conductive film may become uneven. If it is less than 1 micron, the surface area of the microcapsule type curing agent becomes too large, and the storage stability deteriorates. In addition, since the particle diameter of the copper alloy powder is close to that of the copper alloy powder, the microcapsule type hardener having a close particle diameter inhibits the arrangement of the copper alloy powders, and thus has the effect of preventing a decrease in insulation.

As for the curing agent, in addition to the microcapsule type curing agent, if necessary, aliphatic amines, aromatic amines, inorganic carboxylic acids, thiols, alcohols, phenolic compounds, borane compounds, inorganic acids, hydrazides, Imidazole may be added. In the anisotropic conductive composition and film of the present invention, it is preferable to add a thermosetting or thermoplastic resin other than epoxy for adjusting repair performance, coatability, and tackiness, in addition to the epoxy resin. For example, phenoxy resin, polyester resin, acrylic rubber, SBR, NBR, silicone resin, polyvinyl butyral, urethane resin, polyacetal resin, melamine resin, polyamide, polyimide, phenol resin, melamine, guanamine, cyanoacrylate, carboxyl group hydroxyl group, There are rubbers and elastomers containing a functional group such as a vinyl group, an amino group, and an epoxy group. For these resins other than epoxy, epoxy resin 10
Up to 300 parts by weight may be added to 0 parts by weight. Among them, phenoxy resin, polyester resin, acrylic rubber, SBR, NBR, urethane resin, polyacetal resin and the like are preferable. In particular, the amount is preferably 1 to 250 parts by weight based on 100 parts by weight of the epoxy resin.

When the anisotropic conductive composition of the present invention is applied, an appropriate solvent can be used if necessary. In this case, a material that does not damage the microcapsule type curing agent is preferable. For example, aromatic hydrocarbons such as methyl ethyl ketone, toluene, benzene, xylene, methyl isobutyl ketone, ethyl acetate, butyl acetate, ethylene glycol monoethyl acetate, and dioxane, ethers, ketones, and esters are preferred.

The method for producing the anisotropic conductive composition of the present invention is as follows. First, a copper alloy powder, an epoxy resin and, if necessary, a thermoplastic or thermosetting resin other than epoxy, and a solvent, if necessary, in a predetermined amount. It measures and mixes with well-known mixers, such as a planetary mixer, a kneader, a three-roller, a stirrer with a blade, and a ball mill, to produce a mixture in which copper alloy powder is uniformly dispersed.

The viscosity of the anisotropic conductive composition thus obtained is preferably from 1000 cps to 200,000 cps according to the intended use. In this state, the electrodes and terminals on the connection substrate can be used by being applied by a dispenser, screen printing, or the like. When producing a film-shaped anisotropic conductive film, the anisotropic conductive composition is bladed,
It is applied on a base film such as an insulating film by a known application method such as a die coater. The applied substance containing the solvent is dried. The thickness of the anisotropic conductive film is 5 to
It is about 500 microns, and the width is not particularly specified, and it can be used by slitting when connecting. For example, a reel having a width of about 0.2 to 200 mm wound around a reel is preferable. The reel is preferably made of plastic because of its excellent ease of handling, and the reel wound film can be produced from several m to about 1000 m without any displacement and deformation of the film. The reel is preferably provided with a guide.

The anisotropic conductive film of the present invention preferably has an insulating film (herein referred to as a base film) on at least one of the films, so that preservability and workability at the time of connection are improved. preferable. As the base film at this time, a film which is used as a base layer of a coating film of the anisotropic conductive composition, and which can obtain a mechanical strength when wound on a reel or the like is preferable. Titanium oxide, silicone resin treatment, alkyd, inorganic film such as PET, Teflon, polyimide, polyester, polyamide, alumina and tiny alumina, and these base films for controlling the adhesiveness with the anisotropic conductive composition. A film subjected to a treatment such as a resin treatment is preferable. It is preferable to use a base film having a thickness of about 1 to 300 microns. What is applied to the base film in this manner is called a two-layer anisotropic conductive film, and a cover film (that is, the anisotropic conductive composition is sandwiched on the side opposite to the base film) can be used if necessary. . In this case, a material having lower tackiness than the base film is preferable. This can also be used for base film PET, Teflon, polyimide, polyester, polyethylene, polypropylene, polyamide,
It can be produced by a combination of an inorganic film or those obtained by subjecting them to a silicone resin treatment, an alkyd resin treatment, and a titanium oxide treatment. The case where this cover film is used is called a three-layer structure. The anisotropically conductive composition formed into a film using a base film and, if necessary, a cover film is referred to as an anisotropically conductive film. When used, the cover film and the base film are peeled off and used for connection.

The method of using the anisotropic conductive composition is as follows. When the anisotropic conductive composition is used as it is, it is applied using a dispenser or screen printing. In this case, the solvent-free type is preferable because volatilization of a solvent or the like at the time of curing causes generation of voids.
The electrodes or LSI chip electrodes (bumps) on the connected substrate are aligned so as to sandwich the anisotropic conductive composition applied on the electrodes, and heated and pressed with a tool from the connected substrate or LSI chip using a tool to epoxy. To cure. At this time, only the conductive powder located between the electrodes is deformed, and conduction is obtained only in the direction between the electrodes or in the direction between the terminals. Insulation is maintained between adjacent electrodes or between terminals.

In the case of an anisotropic conductive film, a cover film is first peeled off and bonded to an electrode on a connection substrate by utilizing the tackiness of the anisotropic conductive composition. At this time, at the time of bonding, the film is temporarily pressed and heated so that the film is not peeled off, and is temporarily compressed. Further, the base film is peeled off so that only the anisotropic conductive composition is stuck on the connection substrate. The electrodes of the substrate to be connected or the LSI chip are aligned, and are pressed with a tall so as to face the electrodes on the connection substrate so as to sandwich the anisotropic conductive composition.
At this time, the epoxy is cured by applying pressure and heat, and conduction between the facing electrodes is obtained by deformation of the conductive particles. There is no electrical continuity between adjacent electrodes. The anisotropic conductive composition or the anisotropic conductive film of the present invention can deform the conductive particles even when the pressure at the time of pressurization is low, and can obtain high conductivity between the electrodes. There is an advantage that the connection can be performed at a pressure of about ² kg / cm ² to several hundred kg / cm ² . Preferably, it is 5 kg / cm ² to 500 kg / cm ² . The connection can be performed at a heating temperature of 80 to 220 ° C. The heating time can be several seconds to several tens of seconds. Since the conductive particles used in the present invention have good thermal conductivity, they can serve as a heat conductor to the epoxy resin of the composition. Therefore, it is advantageous in that it can be manufactured in a short time and has excellent productivity.

In this way, the electrical connection between the connection substrate and the substrate to be connected or the LSI chip can be achieved via the anisotropic conductive composition or film. As the connection substrate, a liquid crystal display, a plasma display, an electroluminescence display, a printed substrate, a build-up substrate (a multilayer substrate obtained by alternately stacking an insulating layer and a conductive circuit layer, and a photosensitive resin or the like can be used) Alternatively, a substrate provided with electrical wiring, such as a low-temperature fired substrate, can be used. In addition, as a connected board or a connected chip component, a flexible or rigid printed board, a capacitor, a resistor, an LSI
It can be used to connect a chip, a coil, a flexible substrate (TCP; tape carrier package) to which an LSI chip is already connected, and an LSI package such as QFP, DIP, SOP, and the like.

The material of the connection substrate or the substrate to be connected is not particularly limited. For example, polyimide, glass epoxy, paper phenol, polyester, glass, polyetherimide, polyether ketone, polyethylene terephthalate, polyphenylene ether, thermosetting polyphenylene ether The substrate can be used for, for example, polyphenylene sulfide, glass polyimide, alumina, small alumina, tetrafluoroethylene, polyphenylene terephthalate, BT resin, polyamide, photosensitive epoxy acrylate, and low-temperature fired ceramics.

The conductors of the connection electrodes or terminals formed on the connection substrate or the substrate to be connected are not particularly limited, and include ITO (indium-tin-oxide), IO (indium oxide), copper, silver, and silver. Copper alloy, silver palladium,
Gold, platinum, nickel, aluminum, silver platinum, tin-lead solder, tin-silver solder, tin, chromium, nickel-copper alloy,
These conductors include gold-plated, tin-plated, nickel-plated, tin-lead solder-plated, chrome-plated, vapor-deposited and electrodeposited conductors.

The connected chip components include a capacitor, a resistance value, a coil, an LSI chip, a QFP, an SOP,
Although DIP and the like can be used, silver, silver palladium, aluminum, copper, a silver-copper alloy,
Platinum, gold, aluminum, nickel-copper alloy, stainless steel, and the like, and tin, solder, nickel, gold, etc. plated, vapor-deposited, and electrodeposited, can be used.
In the case of a chip or the like, connection can also be made using bumps. The bumps may be formed by plating, gold wire bonding, solder balls, nickel balls, copper balls, or the like. The case where an LSI chip is directly mounted on a glass substrate or a printed circuit board is called COG (chip-on-glass), COB (chip-on-board), or COF (chip-on-film). Can be used. When the anisotropic conductive film or composition of the present invention is used, the surface of the copper alloy powder contains one or more components selected from Si and Ti. It acts as a trapping agent and can improve the environmental resistance to the copper alloy powder, and preferably when included in the form of a coupling agent, can further improve the environmental resistance to water absorption, ensuring insulation resistance at ultra fine pitch. And good connection resistance can be maintained,
In addition, connection in a short time is possible. Therefore, 10
For a 200 micron pitch fine pitch, 10
Connection at an ultra fine pitch of ~ 50 microns is possible. Of course, it can be applied to connection at a wide pitch. At this time, the anisotropically conductive composition or the anisotropically conductive film of the present invention has extremely excellent conductivity, and has a small continuity even when connected at a fine pitch. It can be used for the following applications. In applications where a high current flows, there is also an ability to release heat generated electrically. That is, the copper alloy powder present in the anisotropic conductive composition or film has good thermal conductivity,
It also has the function of radiating heat to the substrate side through this powder.

The conductors and electrodes on the substrate may be formed by plating, etching, curing of conductive paste, sintering of conductive paste, conductive balls, plating, vapor deposition, electrodeposition, sputtering, and the like.

[0037]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the anisotropically conductive composition or anisotropically conductive film of the present invention are shown below.

[0038]

EXAMPLES Table 1 shows examples of the production of the copper alloy powder used in the present invention. First, a predetermined amount of copper and silver particles are placed in a graphite crucible and heated and melted in an inert gas atmosphere using high-frequency induction heating. After dissolution, the powder is jetted into helium or nitrogen in an inert gas atmosphere, and at the same time, a high-speed inert gas is jetted into the melt to rapidly cool and solidify to produce a fine powder. Further, it was cut into a predetermined size by an airflow classifier. The obtained copper alloy powder had a nearly spherical shape, and the average composition and surface composition, average particle size, particle size distribution, and oxygen content were measured by the methods described above. However, the atomized powder preparation example (10) was atomized with air.

The copper alloy powder obtained by atomization was further immersed in a solution of a silane coupling agent or a titanium coupling agent shown in Table 2 with stirring for 10 hours. After partial drying, a part of the powder was dissolved in a concentrated nitric acid solution and measured by ICP-mass. The amounts of Si and Ti contained in the copper alloy powder are shown (Table 3).

Table 4 shows the organic binders (epoxy resins and resins other than epoxy) used by mixing with the copper alloy powder used in the present invention obtained in Table 3. In addition, Table 5 shows a curing agent comprising a microcapsule-type imidazole derivative epoxy compound used simultaneously with the epoxy resin. Tables 6 and 7 show anisotropically conductive compositions and anisotropically conductive films obtained by mixing the copper alloy powders, organic binders, and microcapsule-type curing agents shown in Tables 3, 4, and 5. The anisotropic conductive film was obtained by applying a coating film having a coating width of 100 mm and a thickness of 17 μm with a die coater to a thickness of 50 m using the base film and cover film described in the table. The coatability was evaluated as x when there were 5 or more aggregates within a 1 m long coating film, Δ when 1 to 4 aggregated, and O when 0. The storage stability evaluation of the anisotropic conductive composition and the film was 25
The tackiness when left at 0 ° C. was evaluated, and the initial value of 0.
When the tackiness was lowered to 4 to 0.6, it was marked as Δ. Below that, it was evaluated as x, and when it exceeded 0.6, it was evaluated as ○.

The characteristics of the connection bodies (connection substrate and connection substrate or connection chip) connected using the anisotropic conductive compositions and films shown in Tables 6 and 7 are shown in the evaluation examples of Table 8. For the anisotropic conductive composition and the anisotropic conductive film of the present invention, the connection as shown in the following Table 8 evaluation examples,
The connection resistance, environmental test, insulation test, substrate adhesion, and repairability were examined for the connected substrate, electrode, and pitch. The anisotropic conductive composition is applied on the connecting substrate conductor by screen printing.
The print was about 17 microns thick with a width of mm. In the case of a film of the anisotropic conductive composition (anisotropic conductive film),
Slit the coating film with a width of 2 mm, wind it up on a plastic reel, pull out the length necessary for joining from the reel, remove the cover film, and temporarily attach it so as to cover the conductor on the connection board. Then, the substrate to be connected or the chip to be connected (LSI or the like) was aligned with a CCD camera so that the electrodes faced each other, and then bonded by pressing and heating with a tool. The connection was performed at a pressure of 20 kg / cm ² and a temperature of 170 ° C. for 4 seconds. Evaluation Examples 5 and 14 were 180 ° C. at 10 kg / cm ² ,
The connection was heated and pressurized in 3 seconds.

The connection resistance was measured by the four-terminal method, and was obtained by correcting the connection resistance of each terminal on the substrate. Environmental test is -5
After performing a 3000 cycle test at 5 to 125 ° C. for 30 minutes each and leaving at a high humidity (60 ° C. 90% RH) for 4000 hours, the resistance change rate with respect to the initial connection resistance value is 10
% Or less, and 10% or more and less than 100% Δ, 1
The case where it exceeded 00% was evaluated as x.

In the insulation test, the insulation resistance between adjacent electrodes or terminals was measured, and 10 ¹² ohms or more was evaluated as having good insulation. More than 10 ¹² ohms less than 10 ⁸ ohm △, was × less than 10 ⁸ ohm. At this time, the insulation test between adjacent electrodes was performed at a pitch of 10 to 60 μm, and evaluated after 60 ° C., 90%, and RH 1000 hours.

The repairability is evaluated as follows: the connection substrate is mechanically peeled off, and the residue on the electrode or terminal is repeatedly wiped off with a cotton swab impregnated with acetone. When the number of times of wiping is 100 or less, the residue is removed from the electrode. And The case where complete wiping exceeded 100 times was evaluated as x. Regarding the adhesion strength, ○ indicates that the mechanical peeling strength was 500 gf or more, and X indicates that it was less than that.

The maximum allowable current value is good when the applied DC voltage and the current value have a linear relationship up to 1A.
It was assumed to be. Those that deviated from linearity at 1 A or less were rated as x. The measurement was repeated five times using a constant voltage ammeter (manufactured by Kenwood) by connecting a polyimide substrate and an FR-4 substrate (electrodes formed of copper foil). Table 9, 1
Reference numerals 0, 11, and 12 show anisotropic conductive compositions and films of comparative examples. Table 13 shows the evaluation results of the anisotropic conductive compositions and films of Comparative Examples in Tables 9, 10, 11, and 12. The evaluation method is the same as the embodiment.

[0046]

[Table 1]

[0047]

[Table 2]

[0048]

[Table 3]

[0049]

[Table 4]

[0050]

[Table 5]

[0051]

[Table 6]

[0052]

[Table 7]

[0053]

[Table 8]

[0054]

[Table 9]

[0055]

[Table 10]

[0056]

[Table 11]

[0057]

[Table 12]

[0058]

[Table 13]

[0059]

The anisotropic conductive composition and film of the present invention have the following excellent effects. 1. Since it contains a small amount of silver and the silver concentration on the surface of the copper alloy powder is higher than the average silver concentration, the connection resistance value is low, low resistance is obtained even with fine pitch connection, and environmental resistance (with ultra fine pitch connection) (High humidity storage, heat cycle). 2. Since the copper alloy powder is easily deformed and a sufficient connection area can be obtained, connection can be sufficiently performed even at a low pressure, and damage to the substrate can be reduced. 3. Since it has a particle size distribution and many particles are close to the average particle size, there are many particles suitable for thixotropic properties at the time of coating and effective at the time of connection. 4. Since the copper component on the surface of the powder contains a certain amount of oxygen, the wettability between the epoxy and the copper alloy powder is good, so that it is easy to disperse and the variation in resistance value at fine pitch is small. 5. By using a microcapsule-type curing agent, storage stability at room temperature is excellent, and since copper alloy powder is used, heat conductivity to the anisotropic conductive composition is good, and even when pressed for several seconds. Curability can be sufficiently enhanced. 6. In addition, due to the deformation of the copper alloy powder during pressurization,
Since the macrocapsule-type curing agent at the adjacent position is easily broken and the curability is enhanced, there is an advantage that the properties of the curing agent can be sufficiently exhibited. 7. Furthermore, it has excellent insulation properties when connecting at an ultra fine pitch.

Claims (6)

[Claims] 1. 0.5 to 200 parts by weight of an epoxy resin and 100 parts by weight of an epoxy resin per 1 part by weight of a copper alloy powder having an average particle diameter of 2 to 15 microns having the following features (1) and (2): An anisotropic conductive composition comprising 5-250 parts by weight of a microcapsule-type imidazole derivative epoxy compound as a curing agent per part. (1) General formula Ag _X Cu _1-X (0.001 ≦ x ≦ 0.
6, x is an atomic ratio), and the silver concentration on the surface of the powder is higher than the average silver concentration. (2) One or more components selected from Si and Ti are added in 0.1%.
Contains 1 to 800 ppm 2. Phenoxy resin, polyester resin, acrylic rubber, SB
The anisotropic conductive composition according to claim 1, wherein the composition comprises 1 to 250 parts by weight of at least one selected from R, NBR, silicone resin, polyvinyl butyral resin, and urethane resin. 3. The particle size distribution of the copper alloy powder according to claim 1, wherein the powder having an average particle size within ± 2 μm is 30 to 1%.
The anisotropic conductive composition according to claim 1 or 2, wherein the content of oxygen is from 1 to 10,000 ppm by volume. 4. The microcapsule type imidazole derivative epoxy compound according to claim 1, which has an average particle diameter of 1 to 10.
The anisotropic conductive composition according to any one of claims 1 to 3, wherein the composition is micron. 5. An anisotropic conductive film, wherein the anisotropic conductive composition according to claim 1 is formed into a film. 6. An anisotropic conductive film according to claim 5, wherein the anisotropic conductive film has an insulating film on at least one surface.