JPH1021740A - 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 the surface is coated with 0.01-1 micron thick insulating resin, 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, fine pitch connection is made possible, and withstand voltage 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, LCD TVs,
It is effective for fine pitch applications such as mobile phones, liquid crystal cameras, watches, word processors, copiers, phones, 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.
There is a problem that the environmental resistance is poor and the connection resistance increases. In addition, the pressure at the time of connection is several tens of kg /
cm ² to 100 kg / cm ² , which caused significant damage to the substrate. For example, when used for a glass substrate, the substrate was 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, there is a problem that gold plating peels off when pressurized, and good connection resistance cannot be obtained at fine pitch because it depends on the resistance value of nickel powder itself.
In addition, high pressure is required as in the case of nickel powder. 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.

As an organic binder in which conductive particles are dispersed, an epoxy resin is often used as a thermosetting type from the viewpoint of adhesiveness. However, before an anisotropic conductive composition or film is used, epoxy resin is used. Naturally, a state in which cross-linking is as small as possible is preferable, but depending on the curing agent, when the anisotropic conductive composition is used, the curing of the epoxy has already progressed, often causing poor adhesion to the substrate and poor conduction.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an anisotropic material which can be connected for a short time, has excellent environmental resistance, can be connected at a fine pitch, and has excellent withstand voltage insulation. The present invention provides a conductive composition and a film. That is, the present invention provides 0.5 to 200 parts by weight of an epoxy resin and 100 parts by weight of epoxy resin 100 parts by weight based on 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). Microcapsule-type imidazole derivative epoxy compound 5 as a curing agent per part by weight
It is an anisotropic conductive composition containing up to 250 parts by weight. (1) General formula Ag _X Cu _1-X (0.001 ≦ x ≦ 0.
6, x is the atomic ratio), and the silver concentration on the powder surface is higher than the average silver concentration. (2) The powder surface is coated with an insulating resin having a thickness of 0.01 to 1 micron. The copper alloy powder used in the present invention has a general formula of 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, high conductivity at the time of connection and fine pitch Is that high conductivity can be maintained even if the number of particles 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 0.01
~ 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
(Ag / (Cu + Ag)) calculated from the area values of Cu (2p) and Ag (3d) using a correction coefficient, which was measured by a line photoelectron spectrometer; XSAM800 (manufactured by KRATOS).
It is. Average silver concentration, average copper concentration (Ag /
(Ag + Cu)) and (Cu / (Ag + Cu)) are obtained by dissolving a copper alloy powder in a concentrated nitric acid solution, and dissolving the ICP (high frequency inductively coupled plasma analyzer (manufactured by Seiko Denshi Kogyo; JY38).
It measured using P2).

Further, the copper alloy powder used in the present invention has an insulating resin layer of 0.01 to 1 micron on the surface of the powder. The conductive layer, that is, the metal surface of the copper alloy powder surface is exposed, and good conductivity is obtained between the connection electrodes. In the direction between the adjacent electrodes, even if the conductive powders come into contact with each other, the connection is made. Since the conductive powder that does not contribute to the protection is protected by the insulating resin layer, the insulating property in the direction between adjacent electrodes is maintained. In particular, in the case of a conductive powder in which an insulating resin is coated on the copper alloy powder of the present invention, heat is applied to the entire copper alloy powder itself that contributes to connection by heating and pressurization because of excellent heat conductivity. In addition, since the coated insulating resin is easily melted and removed, the connection time can be shortened, which has the advantage of improving productivity. Since the copper alloy powder to which the insulating resin is removed and connected has excellent environmental resistance and electrical conductivity, it has excellent electrical conductivity in the direction between the electrodes and excellent voltage resistance between adjacent electrodes. is there.

Examples of the insulating resin coated on the copper alloy powder include polyvinylidene fluoride, melamine resin, benzoguanamine resin, polyester resin, polystyrene resin, silicone resin, epoxy resin, polyurethane resin, polyacetal resin, ethyl cellulose, cellulose acetate, Cellulose propionate, ionomer resin,
Polyether sulfone resin, acrylic resin, methacrylic resin, urea resin, polyimide resin, fluororesin,
Polyphenylene oxide, polycarbonate resin, polyether sulfone resin, ABS resin, styrene-butadiene resin, phenol resin, polyethylene, polypropylene, and the like can be used. Among them, polystyrene, benzoguanamine and polyvinylidene fluoride are particularly preferred.

As a method of coating an insulating resin on a copper alloy powder, coacervation, interfacial polymerization, in
Situ polymerization method, chemical method such as in-liquid curing coating method, spray drying method, gas phase suspension coating method, vacuum deposition coating method,
Dry blending, electrostatic coalescence, melting dispersion cooling, inorganic encapsulation, interfacial precipitation and the like are preferred. Among them, the dry blending method is preferable. As the dry blending method, a hybridization system is particularly preferable. For example, polyvinylidene fluoride is mixed with copper alloy powder by several parts by weight and heated at about 90 ° C. for several minutes.
If the treatment, that is, the covering ratio is required to be 50% or more, the treatment is preferably performed for 30 minutes.

The coating of the surface of the copper alloy powder with the insulating resin does not necessarily have to be 100% covered.
% Or more. More preferably, the coating is 30% or more. For coverage ratio, see SE
Observed with M and determined from the area. The thickness of the covering insulating resin layer was determined by cutting the cross section of the copper alloy powder, and averaging the maximum value and the minimum value when the copper alloy powder was coated as the thickness of the insulating resin layer.

The thickness of the coating insulating resin layer is 0.01 to 1
If it is 0.01 μm or less, the shock when the copper alloy powders come into contact with each other may cause a flaw and a conductive path may occur, or the heat at the time of connection may cause some melting and falling off. If it exceeds 1 micron, it takes too much time for heating under pressure, and the productivity is deteriorated. Preferably, it is between 0.01 and 0.5 microns. further,
Preferably, it is between 0.01 and 0.3 microns.

The average particle size of the copper alloy powder is 2-15.
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, preferably, the existence ratio of the powder having an average particle diameter of ± 2 μm or more is 30% or more. 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 (SYMPATEC
(HEROS & RODOS) using the volume integrated average particle diameter. 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 a certain amount of oxygen (oxygen as a hydroxide or oxygen as an oxide) is contained on the surface, so that the wettability with an organic substance when coating an insulating resin from a clean metal surface. And it is easy to uniformly coat the powder surface. The oxygen content may be such that the copper component on the surface is in an oxide or hydroxide state. When it exceeds 10,000 ppm, not only environmental resistance at the time of connection deteriorates, but also
Acceleration of epoxy curing accelerates storage stability. 1p
When it is less than pm, it is difficult to apply an insulating resin coat.
The oxygen content was measured using an oxygen / nitrogen analyzer (EMGA65
0; 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 an epoxy resin as the organic binder, the adhesion to the connection substrate can be improved. 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. Preferably, 2-
150 parts by weight, more preferably 4 to 100 parts by weight.
Parts by weight.

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. By using the microcapsule-type imidazole derivative epoxy compound, the storage stability of the anisotropic conductive composition and the film can be improved. Another advantage is that uniform hardening can be expected in a short time of several seconds of pressurization and 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 breaks through the isocyanate film of the microcapsule when deformed by pressurization, and the hardening can be rapidly accelerated. 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.

The average particle diameter of the microcapsule type curing agent is preferably 1 to 10 μm. If the thickness exceeds 10 microns, the thickness of the anisotropic conductive film becomes uneven when the film is formed. If it is less than 1 micron, the surface area of the microcapsule type curing agent becomes too large, and the storage stability deteriorates. Further, 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 an effect of preventing a decrease in insulation.

As the curing agent, in addition to the microcapsule type curing agent, if necessary, aliphatic amines, aromatic amines, carboxylic acid inorganic substances, thiols, alcohols, phenol 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.

As a method for producing the anisotropic conductive composition of the present invention, 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. Measure and planetary mixer, non-babbling kneader, three rolls, bladed stirrer,
The mixture is mixed by a known mixer such as a ball mill to prepare a mixture in which the 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 a film-shaped, ie, anisotropically conductive film is produced, the anisotropically conductive composition is applied onto a base film such as an insulating film by a known application method such as a blade or a die coater. The applied substance containing the solvent is dried. The thickness of the anisotropic conductive film is about 5 to 500 microns, the width is not particularly specified, and it can be used by slitting when connecting, for example, a thing having a width of about 0.2 to 200 mm. Good thing wound on a reel. 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 one 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 because storage stability and workability during connection are improved. 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 Titanium Alumina, and these base films for control of adhesion with 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 coated on the base film in this way is called a two-layer anisotropic conductive film, and a cover film (that is, the anisotropic conductive composition is sandwiched on the opposite side 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 made of a combination of PET, Teflon, polyimide, polyester, polyethylene, polypropylene, polyamide, inorganic film, or those obtained by subjecting them to a silicone resin treatment, an alkyd resin treatment, or a titanium oxide treatment, which can be used for the base film. . The case where this cover film is used is called a three-layer structure. An anisotropic conductive composition formed into a film using a base film and, if necessary, a cover film is referred to as an anisotropic 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 undergoes deformation, and conduction is obtained only in the direction between the electrodes. Insulation is maintained between adjacent electrodes.

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 anisotropically conductive composition or anisotropically 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 heating temperature is 80
Connection in the range of -220 ° C is possible. 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. for that reason,
It is good 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, polyether imide, 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 conductor of the connection electrode formed on the connection substrate or the substrate to be connected is not particularly limited, and ITO (indium-tin-oxide), IO (indium oxide), copper, silver, silver-copper alloy , Silver palladium, gold, platinum, nickel, aluminum, silver platinum, tin-lead solder, tin-silver solder, tin, chromium, nickel-copper alloy, and gold, tin plating, nickel plating, tin-lead solder plating, chrome, etc. Conductors subjected to plating, vapor deposition, and electrodeposition.

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.

When mounting an LSI chip directly on a glass substrate or a printed circuit board, COG (chip on glass),
Although called COB (chip-on-board) or COF (chip-on-film), the anisotropic conductive composition or film of the present invention can be used as a connection medium also in this case. The anisotropic conductive film or composition of the present invention contains a copper alloy powder coated with an insulating resin on the surface of the copper alloy powder. Is secured. In addition, since the copper alloy powder has good thermal conductivity, the insulating resin coated on the surface of the copper alloy powder contributing to the connection at the time of pressurizing and heating can be melted and quickly removed. Excellent.

For this reason, a connection at a fine pitch of 10 to 200 microns and a connection at an ultra fine pitch of 10 to 50 microns is possible. Of course, it can be applied to connection at a wide pitch. Furthermore, even if a voltage of several tens of volts or a voltage of 100 volts or more is applied between the electrodes, sufficient insulation between adjacent electrodes can be maintained. Naturally, at the time of connection, the anisotropically conductive composition or anisotropically conductive film of the present invention has extremely excellent conductivity, and has a small reduction in conduction even at the connection at a fine pitch, and has a high current application of 100 m.
It can exert sufficient power for applications A and above. Also,
In applications where a high current is passed, there is also the ability to dissipate the heat generated electrically. That is, the copper alloy powder present in the anisotropic conductive composition or film has good heat conductivity, and 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, hardening of conductive paste, sintering of conductive paste, conductive balls, plating, vapor deposition, electrodeposition, sputtering, and the like.

[0038]

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

[0039]

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.

Further, 1 to 30 parts by weight of polyvinylidene fluoride was added to 100 parts by weight of the copper alloy powder in the hybridization system and treated at 90 ° C. for 20 minutes.
The thickness of the insulating resin layer on the surface of the copper alloy powder thus obtained was measured by SEM observation (the thickness was the average value of the maximum and minimum values of the coated surface). Table 1 also shows the thickness at this time.

Table 2 shows 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 1 and used in the present invention. In addition, Table 3 shows a curing agent comprising a microcapsule-type imidazole derivative epoxy compound used simultaneously with the epoxy resin. Tables 4 and 5 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 1, 2, and 3. 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
Evaluate the tackiness when left at ℃, the initial value of 0.4
When the tackiness was reduced 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 properties of the connection bodies (connection substrate and connection substrate or connection chip) connected using the anisotropic conductive compositions and films shown in Tables 4 and 5 are shown in the evaluation examples of Table 6. . For the anisotropically conductive composition and anisotropically conductive film of the present invention, connection, connection substrate, electrode, pitch as shown in the evaluation examples of Table 6 below, connection resistance, environmental test, insulation test, The substrate adhesion and repairability were examined.
The anisotropic conductive composition was printed on the connecting substrate conductor by screen printing to a thickness of about 17 microns with a width of 2 mm. In the case of an anisotropic conductive composition film (anisotropic conductive film), the coating film is slit with a width of 2 mm, wound on a plastic reel, pulled out from the reel to a length required for joining, and covered. After removing the film, temporarily attach to cover the conductor on the connection board, after removing the base film,
Further, a substrate to be connected or a 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 10 seconds.

The connection resistance was measured by a four-terminal method and determined 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.

The withstand voltage insulation test, which is a feature of the anisotropic conductive composition of the present invention, is conducted by applying a pulse voltage of 250 V and a voltage of 1 second 50 times at 60 ° C. and 90% RH for 1,000 hours. The resistance was measured, and 10 ¹² ohms or more was evaluated as having good insulation. Less than 10 ¹² ohms 10 ⁸
Ohms or more △, was × less than 10 ⁸ ohm. The repairability was evaluated as "good" when the connection substrate was mechanically peeled off, and the residue on the electrode or terminal was repeatedly wiped off with a cotton swab soaked with acetone. When the number of times of wiping was 100 or less, the residue was removed from the electrode. The case where complete wiping exceeded 100 times was evaluated as x.

Regarding the adhesion strength, a mechanical peeling strength of 500 gf or more was rated as ○, and a peel strength of 500 gf or less was rated as x. The maximum allowable current value was evaluated as good when the applied DC voltage and the current value up to 1A were in a linear relationship. Those that deviated from linearity at 1 A or less were rated as x.
The measurement is performed using a constant voltage ammeter (manufactured by Kenwood).
In the case of an LSI chip or the like, the bump side was short-circuited, and the connection between the substrates was performed as it was.

[0046]

Comparative Examples Tables 7, 8, 9, and 10 show anisotropic conductive compositions and films of Comparative Examples. Table 11, Tables 7, 8, 9, 10
3 shows the evaluation results of the anisotropic conductive composition and the film of Comparative Example. The evaluation method is the same as the embodiment.

[0047]

[Table 1]

[0048]

[Table 2]

[0049]

[Table 3]

[0050]

[Table 4]

[0051]

[Table 5]

[0052]

[Table 6]

[0053]

[Table 7]

[0054]

[Table 8]

[0055]

[Table 9]

[0056]

[Table 10]

[0057]

[Table 11]

[0058]

The anisotropic conductive composition and film of the present invention have excellent effects in the following points. 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 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. 3. Since the copper component on the surface of the powder contains a certain amount of oxygen, the wettability with the copper alloy powder during coating with the insulating resin is good, so that the coating easily covers the entire surface of the powder. 4. Since it is coated with an insulating resin, it has excellent withstand voltage insulation at a fine pitch. 5. Since the copper alloy powder is coated with the insulating resin, heat during heating is easily transmitted to the powder, and the insulating resin coated with the powder contributing to the connection is easily melted and removed in a short time, and the connection is made in a short time. Is possible.

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 the atomic ratio), and the silver concentration on the powder surface is higher than the average silver concentration. (2) The powder surface is coated with an insulating resin having a thickness of 0.01 to 1 micron. 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 copper alloy powder according to claim 1, wherein 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 oxygen content is 1 to 10000 ppm. Anisotropic conductive composition. 4. The anisotropic conductive composition according to claim 1, wherein the microcapsule type imidazole derivative epoxy compound has an average particle size of 1 to 10 μm. 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.