JPH11120819A - Anisotropic conductive composition and film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve deformability, heat conductivity, high electrical conductivity and reflow resistance by constituting an epoxy resin contained in an organic binder of a specific rate to metallic powder, on which the surface concentration of silver and gold contained together with copper is higher than the average concentration and which has the specific average particle size, so as to have a glycidyl ether bond not less than bifunctions in a naphthalene skeleton. SOLUTION: The composition of this metallic powder is expressed by MxCu1 - x, and has an average particle size of 2 to 15 μm, and is superior in oxidation resistance and electrical conductivity at connecting time, and is close in a thermal expansion coefficient to a connecting object composed mainly of copper. In the formula, M represents Ag or/and Au, and (0.01<=x<=0.6) is realized. Since an organic binder of 1 to 120 pts.wt. contains a naphthalene expoxy resin of a prescribed rate to 1 pts.wt. of the metallic powder, heat resistance and reactivity are improved, and connection failure by stress applied to an end bump at reflow time is reduced. It is satisfactory to include a microcapsule type imidazole derivative at a prescribed rate as a hardening agent to improve preserving time stability.

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,
Used for TAB, FPC connection to L display, COG connection of LSI bare chip, COB connection of LSI bare chip on printed circuit board, COF connection, connection of flexible substrate to display panel, connection of flexible substrate and rigid substrate be able to. 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. Conventionally, many anisotropic conductive films have been disclosed.
No. 7001, Japanese Patent Application Laid-Open No. H4-2242010, an anisotropic conductive film using conductive particles metal-plated on a resin ball, and metal powder such as nickel powder, solder powder and gold-plated nickel powder. An anisotropic conductive film using the same is disclosed (for example, JP-A-61-55).
809).

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. In other words, the metal plating resin powder has conduction only in the plating metal layer, and in the case of fine pitch connection of 50μ, the number of particles contributing to conduction decreases, so the connection resistance further increases and the driving voltage increases. Is required. In the case of metal-plated resin powder, when the conductive powder is deformed by pressure,
The plating peels off and causes insulation failure frequently. In the case of metal powder, nickel powder originally has high intrinsic resistance, but has poor environmental resistance and increases connection resistance. Also, since nickel powder is hard, the pressure at the time of connection is required to be several tens of kg / cm ^2, and therefore, the substrate is greatly damaged. Was awake. In the case of solder powder, the inherent resistance is high among metal powders, and fine pitch connection cannot be performed. In addition, since the melting point is low, a semi-molten state often occurs during heating connection. In the case of gold-plated nickel powder, the gold plating peels off at the time of pressurization, and high pressure is required when nickel is used. Further, if the electrode is soft, the electrode is often deformed. 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.

[0005] In addition, there is a demand that the pressurization time be as short as several seconds from the viewpoint of recent high productivity. However, in the case of using the above-mentioned one, thermal conductivity is poor, and the connection of several seconds is insufficiently cured. The connection failure was remarkable. In the fine pitch connection, terminals with poor connection often occur due to insufficient dispersion of the conductive powder in the film. In addition, although the demand for a high pitch, which is a fine pitch, has been increasing, in a known device, not only the resistance is high but also the thermal conductivity is poor, and the resistance value is increased and the current cannot be passed to some extent. Was the current situation.

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, in the case of a conventional anisotropic conductive film, bare chip mounting of LSI is required. In the course of progress, anisotropic conductive compositions that can be connected to organic substrates that have a significantly different coefficient of thermal expansion from the chip have been required, but for chips with a high aspect ratio, etc., connection failure due to stress at the end bumps Is happening frequently. Organic substrates are required to be connected with high productivity in a short time of 3 to 5 seconds because high temperatures may be used, but the heat resistance of the anisotropic conductive film is insufficient or the heat of the conductive filler is not sufficient. Insufficient conductivity. In addition, reflow at about 260 ° C. is repeated to connect other parts after mounting the bare chip, but the heat resistance for this is insufficient. In addition, in the case of low-molecular-weight epoxy, etc., when stored at room temperature for a long period of time, the anisotropic conductive film protruded from the base film, etc., and when pulled out from the reel, rear transfer was caused. .

[0007]

In order to solve the above-mentioned problems, the present invention provides a general formula M _x Cu _1-x (where M is A
g, at least one selected from Au, 0.01 ≦ x ≦ 0.
6, x is an atomic ratio), and the silver or gold concentration on the surface of the powder is higher than the average silver or gold concentration, and 1 part by weight of a metal powder having an average particle diameter of 2 to 15 μm contains an organic binder containing an epoxy resin. Wherein the epoxy resin contains a naphthalene-type epoxy resin having at least bifunctional or more glycidyl ether bond in a naphthalene skeleton. The present invention provides a conductive composition and a film.

The metal powder used in the present invention has a general formula of M _x C
u _1−x (M is one or more selected from Ag and Au, 0.0
1 ≦ x ≦ 0.6, where x is an atomic ratio), and wherein the silver or gold concentration on the powder surface is higher than the average silver or gold concentration. However, since it is a conductive powder having high conductivity of both copper, silver and gold, high conductivity at the time of connection and 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 0.01, the oxidation resistance is insufficient and the conduction resistance is significantly increased. Preferably, x is 0.0
4 to 0.4. Many electrodes or terminals of a substrate or a connected substrate mainly contain copper. Therefore, even in a test such as a heat cycle, it has a characteristic that the thermal expansion coefficient is close and a change in connection resistance is small. In addition, since the silver and gold concentrations on the surface of the metal powder containing copper as a main component are higher than the average silver and gold concentrations, oxidation deterioration of the metal powder at the connection point with the electrode can be prevented, and migration of silver can be prevented. it can. The silver or gold concentration on the surface of the metal powder is preferably higher than the average silver or gold concentration.

[0009] The silver or gold concentration on the powder surface is determined by XPS
(X-ray photoelectron spectrometer; XSAM800; KRATO
(Ag + Au) from the area values of Cu2p, Ag3d, and Au measured by using a correction coefficient in the apparatus.
/ (Cu + Ag + Au)). Average silver of metal powder,
The gold and copper concentrations were measured by dissolving the metal powder in concentrated nitric acid or aqueous solution and using an ICP (high frequency inductively coupled plasma analyzer (manufactured by Seiko Instruments Inc .; JY38P2)).
In addition, the copper alloy powder used in the present invention may be Pt, Sn, Zn, Pd, P, B, C, as long as the properties are not impaired.
Ti, Si, V, Mg, Al, Hf, Pb, Mn, Ni
Etc. may be added.

The average particle size of the metal powder is 2 to 15 μm.
When the particle size is less than 2 μm, the conductive particles sandwiched between the electrodes at the time of pressurization have a roughness level of the electrode surface, resulting in poor conductivity and poor environmental resistance. If it exceeds 15 μm, the number of conductive particles between the electrodes becomes insufficient due to the inter-electrode bonding at a fine pitch, and the connection resistance becomes unstable. Preferably, the average particle size is 2 to 13 µ. Also, preferably,
It is preferable that the abundance of the powder having an average particle diameter of ± 2 μm is 30% or more because there are many conductive powders that effectively participate in conduction between the electrodes. 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 average particle diameter used in the present invention refers to a laser diffraction type measuring apparatus RODOS SR (SYMPATEC HER).
OS & RODOS) was used to calculate the volume average particle diameter. The presence of the metal powder within an average particle diameter of ± 2 μ was read from a volume integrated particle size distribution meter.

The metal 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 silver, gold, or copper melt having such a composition is pulverized into fine particles by rapid collision with an inert gas, and rapidly solidified. Is what you do. The shape is
Spherical, scaly, dendritic, etc. can be used. In addition, a copper powder or a copper alloy powder whose surface is plated with silver or gold may be used.

[0012] The anisotropic conductive composition or film of the present invention has 0.1 to 120 parts by weight of an organic binder containing an epoxy resin per 1 part by weight of the metal powder of the composition, and has a naphthalene skeleton as the epoxy resin. It is an object of the present invention to provide an anisotropic conductive composition and a film, comprising a naphthalene type epoxy resin having at least a bifunctional or more glycidyl ether bond. The amount of organic binder is preferably between 0.1 and 80, more preferably between 0.1 and 80.
It is 3 to 60 parts by weight.

Here, the naphthalene skeleton contains a polyfunctional epoxy resin having at least a bifunctional or more glycidyl ether group. By using the naphthalene skeleton, heat resistance can be improved. In addition, the glycidyl ether type polyfunctional group is used to improve the reactivity, and in particular, in a bare chip connection having a high aspect ratio and a large number of bumps, the conventional technology applies stress to the bumps at the end during reflow, Connection failure has occurred. For the first time, the reflow resistance can be significantly improved by the anisotropic conductive composition of the present invention. That is, the conduction performance can be improved by using the metal powder having such a composition. further,
When subjected to a thermal shock such as a heat cycle, the metal powder has a coefficient of thermal expansion close to that of gold bumps such as chip bumps and copper bumps, can withstand heat cycles, and has a naphthalene skeleton epoxy resin. It was found that the coefficient of thermal expansion of the whole organic binder could be reduced, and that the heat cycle test of fine pitch showed remarkably stable connectivity. In addition, the metal powder used in the present invention has an almost spherical shape, has excellent wettability with a binder resin, can improve the dispersibility of metal powder, and has an insulating property between adjacent terminals in fine pitch connection. Can be secured.

The naphthalene type epoxy resin of the present invention has
It preferably has a tetrafunctional glycidyl ether bond. In the case of exceeding four functions, the melt viscosity is high and a high pressure is required at the time of pressing. If it is less than bifunctional, the cured resin strength is low. In particular, the epoxy resin having a naphthalene skeleton is preferably a semi-solid type at room temperature. For example, the epoxy equivalent is preferably about 130 to 260 g / eq. Among them, a naphthalene epoxy resin having a glycidyl ether bond in 1,6 is preferable.

As the naphthalene skeleton epoxy resin,
It is preferred from the viewpoint of reactivity that the organic binder is contained in an amount of 10 parts by weight or more in 100 parts by weight of the organic binder. Further, the present invention provides, as an organic binder, a 2,3 having a naphthalene skeleton.
In addition to the tetrafunctional glycidyl ether type epoxy resin, bisphenol A type, bisphenol F type, phenol novolak type, cresol novolak type, alicyclic, alkyl polyphenol type, urethane modified type, fatty acid modified type, rubber modified type epoxy resin, And phenoxy resin, urethane resin, polyester resin, acrylic resin, SBR, NB
R, which provides an anisotropic conductive composition characterized by containing one or more resins selected from silicone resins, wherein one or more resins selected from the above in addition to the naphthalene skeleton epoxy resin By containing a resin, it is possible to adjust the viscosity of the coating film in the case of coating and film formation widely. That is, by the combination of the binder and the metal powder of the present invention, there is no deformability of the metal particles at the time of coating, has a hardness having sufficient deformability at the time of pressing, and the coating viscosity of the organic binder used in the present invention. Is that the viscosity of the coating film can be adjusted without lowering the reactivity. If the conventional bisphenol A type alone was used, the viscosity was too soft and the heat resistance was poor, which was a problem in the production process and in the characteristics. This is because if the viscosity of the coating film is too soft, stains occur during storage of the resin, resulting in poor transferability.

Furthermore, since the thermal expansion coefficient of the naphthalene skeleton epoxy resin is small, the thermal conductivity of the metal particles of the present invention is good, and the thermal expansion is close to that of materials such as bumps, the connection failure due to the heat cycle is significantly reduced. Can be improved.
The epoxy resin other than the naphthalene skeleton epoxy resin is shown above, but it is preferable to use an epoxy resin such as bisphenol A, F type, alicyclic type or novolak type in order to adjust the film viscosity. It is preferable to use a resin at the same time.

The curing agent for the epoxy resin in the organic binder used in the present invention contains 0.5 to 250 parts by weight of a microcapsule-type imidazole derivative epoxy compound as a curing agent based on 100 parts by weight of the epoxy resin. Preferably, as a microcapsule-type imidazole derivative epoxy compound, a reaction product of the imidazole derivative and the epoxy compound is finely powdered by grinding or the like, and further reacted with an isocyanate compound or the like,
It is a product with increased stability at room temperature by being encapsulated. By using the microcapsule-type imidazole derivative epoxy compound, the storage stability of the anisotropic conductive composition and the film can be improved. In addition, uniform hardening can be performed in a short time of several seconds of pressurization and heat bonding.
The reaction does not gradually progress during heating, but rather spreads into the inside of the film within a time period of several seconds, enabling uniform curing.
Further, since the metal powder used in the present invention easily conducts heat, there is an advantage that heat can be easily transmitted to the microcapsule-type curing agent dispersed in the organic binder, and uniform curing can be promoted. That is, sufficient curability can be obtained even in a short time of several seconds. Further, by using the metal powder according to the present invention, the metal powder can break through the isocyanate coating of the microcapsule at the time of pressurized deformation, and the curing 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 the solidification of the epoxy near the pressure bonding temperature. As the imidazole derivative at this time, for example, imidazole, 2-methylimidazole, 2-
Ethyl imidazole, 2-ethyl-4-methyl imidazole, 2-phenyl imidazole, 2-phenyl-4 methyl imidazole, 1-benzyl-2-methyl imidazole, 1-benzyl-2 ethyl imidazole, 1-benzyl-2-ethyl-5-methyl imidazole, 2-phenyl-4-methyl-5 -Hydroxymethylimidazole, 2-phenyl4,5-dihydroxymethylimidazole and the like. Further, as the epoxy compound, bisphenol A, bisphenol F, phenol novolak,
Glycidyl ether type epoxy resins such as brominated bisphenol A, dimer acid diglycidyl ester, phthalic acid diglycidyl ester and the like can be mentioned. The microcapsule type imidazole derivative epoxy compound curing agent is preferably 5 to 25 parts by weight based on 100 parts by weight of the epoxy resin.
0 parts by weight. If the amount is less than 5 parts by weight, curing will be insufficient. If it exceeds 250 parts by weight, the storage stability will be poor. Preferably, it is 5 to 150 parts by weight.

The average particle size of the microcapsule type curing agent is preferably 1 to 10 μm. that is,
If the thickness exceeds 10 μm, the thickness of the anisotropic conductive film may be uneven. If it is less than 1 μm, 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 microcapsule-type curing agent is equivalent to the particle diameter of the metal powder, it is effective in preventing insulation deterioration due to the arrangement of the metal powders.

It is preferable that the microcapsule type imidazole derivative epoxy compound has an average particle size of 1 to 10 μm and a ratio of the minimum particle size to the maximum particle size of 0.001 to 0.6. When the diameter ratio is less than 0.001, sufficient mechanical breakage and thermal breakage of the charged hardening agent do not easily occur during pressure welding, and insufficient hardening and unevenness are likely to occur. When the particle diameter ratio exceeds 0.6, it is good that the connection chip or substrate and the substrate to be connected have sufficient parallelism, but if there is warpage of the substrate, the gap between the electrodes is low. However, the connection unevenness is more likely to occur.

In particular, since the microcapsules having a small particle diameter are continuously broken mechanically as the electrodes become narrower during the pressure welding process as they become narrower, it is necessary to maintain sufficient curing performance until the end of the pressure welding process. A stable connection is possible.
For this reason, there is an advantage that even if the connection has a large variation in height, such as a bump of an LSI chip, the distribution of the curing agent size can be used to buffer the variation in curability.

The average particle size, the minimum particle size, and the maximum particle size of the hardener of the microcapsules are measured with the same measuring device as for the metal powder. The minimum particle diameter indicates a particle diameter at 5% by volume integrated particle diameter. The maximum particle size refers to a particle size at 98% by volume integrated particle size. As for the curing agent, in addition to the microcapsule type curing agent, if necessary, an aliphatic amine, an aromatic amine, a carboxylic acid inorganic substance, a thiol, an alcohol, a phenol compound, a boso compound, an inorganic acid, hydrazide, and imidazole are added. May be.

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.

Further, a coupling agent or the like can be added to the anisotropic conductive composition of the present invention in order to improve the dispersibility of the metal particles. For example, titanium coupling agent,
A silane coupling agent, an aluminum coupling agent or the like can be added up to about 10 parts by weight based on 100 parts by weight of the epoxy resin. As a method for producing the anisotropic conductive composition of the present invention, first, a predetermined amount of a metal powder and an epoxy resin and, if necessary, a thermoplastic or thermosetting resin other than epoxy, a solvent and a coupling agent as required. 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 50,000 CPS depending on the application. 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
The width is about 500 μm, and the width is not particularly specified, and can be used by slitting when connecting. For example, a reel wound with a width of about 0.2 to 200 mm 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 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 resin treatment for inorganic films such as PET, Teflon, polyimide, polyester, polyamide, alumina and alumina nitride, and these base films for control of adhesion with anisotropic conductive composition And the like. It is preferable to use a base film having a thickness of about 1 to 300 μm. What is applied to the base film in this way is 2
Although the layer is referred to as an anisotropic conductive film, a cover film (that is, the anisotropic conductive composition is sandwiched on the side opposite to the base film) can be used as necessary. In this case, a material having lower tackiness than the base film is preferable. This can also be used for base film PE
It can be made of T, Teflon, polyimide, polyester, polyethylene, polypropylene, polyamide, an inorganic film, or a combination of those treated with a silicone resin, an alkyd resin, and a titanium oxide. 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, it goes without saying that 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 by a tool 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 pressurizing and heating, and conduction between the facing electrodes is obtained by deformation of the metal particles. There is no electrical continuity between adjacent electrodes. The anisotropically conductive composition or the anisotropically conductive film of the present invention can deform metal particles even at a low pressure, thereby obtaining high conductivity between 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.

Thus, the electrical connection between the connection substrate and the substrate to be connected or the LSI chip can be achieved through 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 connecting substrate or the substrate to be connected is not particularly limited. For example, polyimide, glass epoxy, paper phenol, polyester, glass, polyetherimide, polyetherketone, polyethylene terephthalate, polyphenylene ether, thermosetting polyphenylene ether , Polyphenylene sulfide, glass polyimide, alumina, alumina nitride, tetrafluoroethylene, polyphenylene terephthalate, BT resin, polyamide, photosensitive epoxy acrylate, low-temperature fired ceramics, build-up substrate, and the like.

The conductor of the connection electrode formed on the connection substrate or the substrate to be connected is not particularly limited. 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, and these conductors are plated with gold, tin, nickel, tin-lead solder, chrome, etc. Conductor, or a conductive paste mainly composed of silver, silver palladium, copper, or the like.

The connected chip components include a capacitor, a magnetic sensor, a resistor, a coil, an LSI chip,
FP, SOP, etc. can be used, but as connection electrodes, silver, silver palladium, aluminum, copper, silver-copper alloy, platinum, gold, aluminum, copper-nickel alloy and the like, and tin, solder, nickel, gold Can be used. In the case of an LSI chip or the like, connection can also be made using bumps (electrodes). The bumps may be formed of gold plating, gold wire bonding, solder balls, nickel balls, copper balls, or the like.

COG (chip-on-glass) refers to the case where an LSI chip is directly mounted on a glass substrate or a printed circuit board.
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. When the anisotropic conductive film or composition of the present invention is used, the pitch of the electrodes to be connected is 10 to 1
The effect can be particularly exhibited in connection at a wide pitch of 000 μ pitch.

The conductors and electrodes on the connection board are plated by a plating method,
Etching method, conductive paste hardening, conductive paste sintering,
It may be made by a conductive ball, electrodeposition or the like.

[0034]

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

[0035]

EXAMPLES Table 1 shows examples of the production of the copper alloy powder used in the present invention. First, a predetermined amount of copper, silver, and gold particles are put 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 has a nearly spherical shape, and the average composition and surface composition, the average particle size, and the particle size distribution were measured by the methods described above. In addition, copper powder and gold atomized copper powder were further prepared. However, the powder preparation example 10 was atomized with air.

Table 2 shows an organic binder and a curing agent used by mixing with the metal powder obtained in Table 1. Table 3 shows anisotropic conductive compositions and anisotropic conductive films obtained by mixing the metal powders, organic binders, and microcapsule-type curing agents shown in Tables 1 and 2, and Table 4 shows evaluation examples. The anisotropic conductive composition was adjusted to an appropriate viscosity (1000 CPS) with a solvent. An anisotropic conductive film is formed using a base film and a cover film of a PET film base, and has a coating width of 100
mm and 50 m coated with a die coater. The coating properties are as follows: after slitting to 1.5 mm width, leaving at room temperature for 2 months, peeling off from base film at a rate of 10 cm / sec, and 2 kg / cm ² 70 ° C. for glass substrate
The case where the transferability in 2 seconds was good was evaluated as ○.

Example (3) in Table 3 was printed in the form of a line having a thickness of 1 mm and a thickness of 20 μm after storage at room temperature for 2 months in the paste state, and after 30 minutes at room temperature, the sag width was 0.2 m.
The condition within m was defined as good. 180 ° C 15
Surface roughness is ± 5μ with a surface roughness meter when cured in seconds
When it was within, the transferability was determined to be good. The continuity is measured by a four-terminal method and is a connection resistance of each terminal on the substrate. An environmental test (3000 cycle test at −55 to 125 ° C. for 30 minutes each) is performed and both ends (at the end of the chip, at the end). The rate of change of 10% or less with respect to the initial connection resistance value of the connection electrode at the position where the stress is most applied) was evaluated as ○.

The reflow resistance was evaluated at an ultimate temperature of 260 ° C. for 5 minutes 4 times after passing through a reflow furnace.
% When the rate of change was less than%. Insulation resistance test, measures the insulation resistance of the adjacent electrodes or terminals of (200V), an insulating 10 ¹² ohms or higher was ○ good. Regarding the adhesion strength, the symbol “○” indicates that the mechanical peeling strength after passing through the reflow furnace four times was 500 gf / cm (converted value) or more.

[0039]

Comparative Example Table 5 shows anisotropic conductive compositions and films of Comparative Example. Table 6 shows the evaluation results of the anisotropic conductive composition and the film of Comparative Example in Table 5. The evaluation method is the same as the embodiment.

[0040]

[Table 1]

[0041]

[Table 2]

[0042]

[Table 3]

[0043]

[Table 4]

[0044]

[Table 5]

[0045]

[Table 6]

[0046]

The anisotropic conductive composition and film of the present invention have excellent effects in the following points. 1. Since the silver or gold concentration is high on the particle surface, the connection can be made in a short time due to the excellent deformability and thermal conductivity, the environment resistance is excellent, and the connection resistance is low. 2. In combination with the epoxy resin having a naphthalene skeleton, stress can be buffered due to a change in thermal expansion at the time of connection of the LSI chip, and connection failure at the end during repeated reflow can be reduced. 3. The microcapsule type curing agent has a particle size distribution, and can exhibit a sufficient buffering effect of the curability variation in the connection process (as the distance between the electrodes becomes narrower) even if the variations in bump height and the like match. 4. It has high film viscosity and has sufficient peeling properties and transfer properties even when left at room temperature for 2 months.

Claims (6)

[Claims] 1. A powder represented by a general formula M _x Cu _1-x (M is at least one selected from Ag and Au, 0.01 ≦ x ≦ 0.6, and x is an atomic ratio). Anisotropically conductive composition having a silver or gold concentration higher than the average silver or gold concentration, and 0.1 to 120 parts by weight of an organic binder containing an epoxy resin per 1 part by weight of a metal powder having an average particle diameter of 2 to 15 μm. Wherein the epoxy resin contains a naphthalene-type epoxy resin having at least a bifunctional or more glycidyl ether bond in a naphthalene skeleton. 2. The organic binder according to claim 1,
In addition to naphthalene type epoxy resins having a 2,3,4-functional glycidyl ether bond of a naphthalene skeleton, bisphenol A type, bisphenol F type, phenol novolak type, cresol novolak type, alicyclic type, alkyl polyhydric phenol type, urethane modified type , Fatty acid modified type, rubber modified type epoxy resin, phenoxy resin, urethane resin, polyester resin, acrylic resin, SBR, NB
R. An anisotropic conductive composition comprising one or more resins selected from silicone resins. 3. The epoxy resin 10 according to claim 1, wherein
An anisotropic conductive composition comprising 5-250 parts by weight of a microcapsule-type imidazole derivative epoxy compound as a curing agent with respect to 0 parts by weight. 4. The metal powder according to claim 1, wherein in the particle size distribution of the metal powder according to claim 1, powder having an average particle diameter of ± 2 μm is 30 to 100% by volume or more. One conductive composition. 5. The microcapsule type imidazole derivative epoxy compound according to claim 3, which has an average particle size of 1 to 10.
μ, and the minimum particle size / maximum particle size ratio is 0.001 to
The anisotropic conductive composition according to claim 1, wherein the composition is 0.6. 6. An anisotropic conductive film, wherein the anisotropic conductive composition according to claim 1 is formed into a film.