JP2017200965A - Liquid conductive resin composition and electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid conductive resin that has a low viscosity and a high conductivity, and shows stable electric characteristics even in a high temperature-high humidity environment.SOLUTION: A liquid conductive resin composition contains the following (A)-(E) components: (A) epoxy resin that is liquid at 25°C, (B) a curing agent that is liquid at 25°C and has one or more phenolic hydroxyl group in the molecule, (C) a curing accelerator, (D) carbon black comprising primary particles with an average particle size of 10-60 nm and having a specific surface of 30-400 m/g, and (E) thermoplastic resin particles that are solid at 25°C.SELECTED DRAWING: None

Description

  The present invention relates to an electrically stable liquid conductive resin composition suitable for use as an adhesive material in an electronic device or a semiconductor package, and an electronic component having the composition as an adhesive.

Conductive adhesives are used for a variety of applications in the manufacture and assembly of electronic devices and semiconductor packages. For example, a conductive adhesive is used as a die bonding adhesive for mounting an integrated circuit chip on a substrate or a surface mounting conductive adhesive for mounting a circuit assembly on a printed wiring board. As particles for imparting conductivity to these conductive adhesives, metal fillers such as copper powder and silver powder and carbonaceous powder such as carbon black are generally used. A conductive adhesive using a metal filler is generally excellent in electrical conductivity and has a volume resistance of about 10 ⁻⁴ to 10 Ω · cm. However, when a metal filler is used, there are the following problems.

  Examples of adhesion targets for conductive adhesives include lead frames and copper wiring. When the adhesion target is different from the metal filler contained in the conductive adhesive, ionization occurs due to the difference in standard electrode potential between different metals. A potential difference is generated between a metal having a large tendency and a metal having a small tendency, a local battery is formed, and corrosion is caused by a local current.

  In addition, there is a phenomenon called migration in which a metal component moves on or across a nonmetallic medium in the presence of an electric field. Migration includes ion migration and electromigration. Ion migration occurs when the current density is low at a relatively low temperature from room temperature to around 100 ° C. in a high humidity environment. It is generated by the movement and precipitation of metal ions in which metal atoms are cationized by the potential difference and the presence of water. On the other hand, electromigration occurs when metal atoms gradually move due to exchange of momentum between electrons and metal atoms moving through the conductive material. Ion migration is often a major problem in conductive adhesive using parts of electronic devices and semiconductor packages. Ion migration occurs with various metals, but silver, which is often used as a filler because of its low conductivity, is most likely to generate ion migration. In order to solve this problem, a conductive resin composition has been developed in which thermoplastic resin particles are added and the volume resistivity can be lowered even if the amount of conductive filler added is small (Patent Literature). 1) Even with this composition, it cannot be said that the above-mentioned problem of ion migration can be solved.

  Furthermore, when exposed to high temperatures, the surface of the metal filler is easily oxidized, and a decrease in conductivity due to oxidation may be a problem. This problem occurs particularly when a copper filler is used.

On the other hand, there is a carbon-based conductive resin using a carbonaceous powder as particles for providing conductivity. For example, a solid conductive resin composition (Patent Document 2), graphite, or carbon, which is formed into a fuel cell separator by injection molding or transfer molding, in which carbon black and graphite powder are mixed and dispersed in a thermosetting resin. A liquid conductive resin composition using carbonaceous powder such as black and kneaded and dispersed in an organic solvent together with a binder made of a curable resin such as phenol resin, epoxy resin, alkyd resin (Patent Documents 3 and 4) )and so on. In addition, a liquid conductive paint and conductive adhesive (Patent Document 5) in which carbon nanotubes are kneaded and dispersed in an organic solvent together with a binder made of polyvinyl acetal and a curable resin have been reported. The volume resistance value of the carbon-based conductive resin is about 10 ^{−3 to} 100 Ω · cm, and the electrical conductivity is inferior to the conductive resin using the metal filler described above. There is no concern about metal corrosion, migration, or increase in resistance value due to oxidation of the surface of the metal filler, and stable conductive properties are exhibited.

  The above-described carbon-based conductive resin is liquefied by using an organic solvent or a reactive diluent. In order to increase conductivity, the amount of carbonaceous powder must be increased. If no solvent or reactive diluent is used, the viscosity increases even when dispersed in a low-viscosity liquid resin. It becomes difficult to use in processes such as printing and dispensing. Viscosity decreases due to the blending of organic solvents and reactive diluents, and it can be used in printing and dispensing processes. However, when such a liquid resin is used as an adhesive between substrates, the following problems occur: Happens. After the resin composition is applied to the substrate in a process such as printing, voids are generated due to volatilization of the organic solvent or reactive diluent when the object to be bonded is attached and cured. If an organic solvent drying process is put in before attaching the object to be bonded, not only will the number of processes increase, but there will be a void due to the solvent that has not volatilized, and the adhesion with the object to be bonded due to an increase in viscosity or solidification of the adhesive. This decreases the adhesiveness and causes a decrease in adhesive strength after curing.

JP 2013-139494 A JP 2001-67932 A JP 09-31402 A Japanese Patent Laid-Open No. 04-38803 JP 2014-28900 A

  An object of the present invention is to provide a liquid conductive resin composition that has a low viscosity and does not generate voids upon curing, and that can provide a cured product having high electrical conductivity and stable electrical characteristics even under high temperature and high humidity. .

  As a result of intensive studies to solve the above problems, the present inventors have found that epoxy resin, carbon black having a specific primary particle diameter and a specific surface area, and thermoplastic resin particles that are solid at 25 ° C. It has been found that a liquid conductive resin composition having high electrical conductivity and stable electrical characteristics even under high temperature and high humidity can be obtained by containing a specific amount of Completed the invention.

  That is, the present invention provides the following liquid conductive resin composition.

[1]
The liquid conductive resin composition containing the following (A)-(E) component.
(A) Liquid epoxy resin at 25 ° C. (B) Curing agent liquid at 25 ° C. having one or more phenolic hydroxyl groups in the molecule (A) Phenol in component (B) relative to 1 equivalent of epoxy group in component (C) Curing Accelerator (A) 0.05 to 10 parts by mass (D) primary with respect to a total of 100 parts by mass of component (A) and component (B) Carbon black having an average particle diameter of 10 to 60 nm and a specific surface area of 30 to 400 m ² / g 1 to 30 parts by mass and a resin with respect to 100 parts by mass in total of component (A) and component (B) The proportion of the whole composition is 0.5 to 22% by mass
(E) Thermoplastic resin particles that are solid at 25 ° C. The proportion of 1 to 50 parts by mass and the total resin composition is 0.5 to 30 parts by mass with respect to 100 parts by mass in total of the components (A) and (B). %
[2]
The liquid conductive resin composition according to [1], further comprising (F) an inorganic filler.
[3]
The molecular weight in terms of polystyrene of the component (E) is 1,000 to 10,000,000 in the number average molecular weight, and the weight average molecular weight is 10,000 to 100,000,000 [1] or [2] Liquid conductive resin composition as described in 2.
[4]
The component (E) is at least one thermoplastic resin particle selected from the group consisting of acrylic resin, methacrylic resin, phenoxy resin, butadiene resin, polystyrene resin, and copolymers thereof [1] to [3]. The liquid conductive resin composition according to any one of the above.
[5]
(E) The liquid conductive resin composition according to any one of [1] to [4], wherein the thermoplastic resin particles are formed from linear molecular chains.
[6]
The liquid conductive resin composition according to any one of [1] to [5], which contains neither a solvent nor a reactive diluent.
[7]
The liquid conductive resin composition according to any one of [1] to [6], wherein the viscosity at a shear rate of 2.00 (sec ⁻¹ ) is ^{1 to} 300 Pa · s at 25 ° C. using an E-type viscometer. object.
[8]
The gelled product of the liquid conductive resin composition according to any one of [1] to [7].
[9]
An electronic component having a cured product of the liquid conductive resin composition according to any one of [1] to [7] as an adhesive.

The liquid conductive resin composition of the present invention uses a specific carbon black and specific thermoplastic resin particles, so that it has a low viscosity without using a solvent or a reactive diluent, and has a workability such as dispensing and printing. The cured product exhibits high conductivity. In addition, since no metal filler is used, stable electrical characteristics can be obtained even under high temperature and high humidity.
And since the liquid conductive resin composition of the present invention has low viscosity, it is excellent in workability such as dispensing and printing, and liquid conductive resins such as die bond materials, heat sink adhesives and lid seal materials that require conductivity It is suitable as a composition, and an electronic component having high adhesiveness and high reliability can be obtained by using the composition as an adhesive.

The schematic diagram of the quartz board which printed each composition in the migration test in the shape of a comb.

  Hereinafter, the present invention will be described in detail.

(A) Epoxy Resin The epoxy resin of component (A) used in the present invention is not particularly limited as long as it is liquid at 25 ° C., but preferably has two or more epoxy groups in one molecule. , Phenol novolac type epoxy resin, cresol novolac type epoxy resin and other novolak type, bisphenol A type epoxy resin, bisphenol F type epoxy resin and other bisphenol type, biphenyl type, phenol aralkyl type, dicyclopentadiene type, naphthalene type, and amino Examples thereof include various epoxy resins such as group-containing types, polyfunctional epoxy resins having one aromatic ring such as a phenylene ring in the molecule, and mixtures thereof. Further, the epoxy resin may contain a silicone-modified epoxy resin. By including the silicone-modified epoxy resin, it is possible to relieve the stress of the resulting cured product and suppress the generation of cracks, and further impart thermal shock resistance to the semiconductor device. A known silicone-modified epoxy resin may be used, and examples thereof include a silicone-modified epoxy resin represented by the following formula (1).

(In formula (1), R ⁵ is a substituted or unsubstituted monovalent hydrocarbon group, R ⁷ is —CH ₂ CH ₂ CH ₂ —, —OCH ₂ —CH (OH) —CH ₂ —O—CH _2. CH ₂ CH ₂ — or —O—CH ₂ CH ₂ CH ₂ —, R ⁶ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, n represents 4 to 199, preferably 19 to 109, and p represents 1 to 10, q represents 1 to 10)

Among these, a silicone-modified epoxy resin in which R ⁵ is a methyl group, R ⁶ is a hydrogen atom, and R ⁷ is —OCH ₂ —CH (OH) —CH ₂ —O—CH ₂ CH ₂ CH ₂ — is preferable. In the present invention, the (A) epoxy resin needs to be liquid at 25 ° C., and particularly preferably liquid at 25 ° C. to 200 ° C. Especially, a liquid epoxy resin is preferable at room temperature (25 degreeC), such as a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, or an epoxy resin which has one aromatic ring.

  In the above description, examples of the epoxy resin having one aromatic ring in the molecule include the following.

(B) Curing Agent The curing agent used in the present invention is a curing agent that is liquid at 25 ° C. having one or more phenolic hydroxyl groups in the molecule, and a known curing agent for epoxy resins can be used. . Among these, a phenol resin is preferable in consideration of the balance between curability and stability in the B-stage state. Examples of the phenol resin include novolak type, bisphenol type, trishydroxyphenylmethane type, naphthalene type, cyclopentadiene type, and phenol aralkyl type, and these may be used alone or in combination of two or more. Further, the composition of the present invention may contain a silicone-modified phenol resin. By including the silicone-modified phenolic resin, it is possible to relieve the stress of the resulting cured product and suppress the generation of cracks, and to impart thermal shock resistance to electronic components and semiconductor devices. A known silicone-modified phenol resin may be used. For example, a silicone-modified phenol resin represented by the following formula (4) may be used.

(In Formula (4), R ¹ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or an organoxy group having 1 to 6 carbon atoms, and R is a substituted or unsubstituted monovalent hydrocarbon not containing an aliphatic unsaturated group. Group, X represents a divalent organic group, Y represents an organic group having a double bond at the terminal, m is a number satisfying 1 ≦ m ≦ 20, and n is 0 ≦ n ≦ 400.

  Of these, bisphenol-type phenol resins and novolac-type phenol resins which are liquid at room temperature (25 ° C.) are preferable.

  The compounding quantity of a hardening | curing agent is equivalent ratio [(B) of the epoxy reactive group in (B) component (when (B) component is a phenol resin, phenolic hydroxyl group) with respect to 1 equivalent of epoxy groups in (A) component. ) Equivalent of epoxy reactive group in curing agent / equivalent of epoxy group in component (A)] is in the range of 0.8 to 1.25, preferably in the range of 0.9 to 1.1. If the blending equivalent ratio (molar ratio) is less than 0.8, unreacted epoxy groups remain in the resulting cured product, and the glass transition temperature may decrease or the adhesion to the substrate may decrease. . If it exceeds the upper limit of 1.25, the cured product becomes hard and brittle, and cracks may occur during reflow or temperature cycling.

(C) Curing accelerator Examples of the curing accelerator include basic organic compounds such as organic phosphorus, imidazole, and tertiary amine. Examples of organic phosphorus include triphenylphosphine, tributylphosphine, tri (p-toluyl) phosphine, tri (p-methoxyphenyl) phosphine, tri (p-ethoxyphenyl) phosphine, and other triarylphosphines, And triphenylborate derivatives, tetraphenylphosphine / tetraphenylborate derivatives, and the like. Examples of imidazole include alkyl imidazoles such as 2-methylimidazole, 2-ethylimidazole and 2-ethyl-4-methylimidazole, aryl imidazoles such as 2-phenylimidazole and 2-phenyl-4-methylimidazole, 2 -Hydroxy-4-imidazole such as phenyl-4-methyl-5-hydroxymethylimidazole and 2-phenyl-4,5-dihydroxymethylimidazole; examples of tertiary amines include triethylamine, benzyldimethylamine, α- And methylbenzyldimethylamine and 1,8-diazabicyclo [5.4.0] undecene-7.

  Among these, a tetraphenylphosphine / tetraphenylborate derivative represented by the following formula (5) or a methylolimidazole derivative represented by the following formula (6) is preferable.

(In formula (5), R ^{7 to} R ¹⁴ each independently represents a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or a halogen atom.)

(In the formula (6), R ¹⁵ represents a methyl group or a methylol group, and R ¹⁶ represents a hydrocarbon group having 1 to 10 carbon atoms.)

  The compounding quantity of a hardening accelerator is 0.05-10 mass parts with respect to a total of 100 mass parts of (A) epoxy resin and (B) curing agent, and shall be 0.1-5 mass parts. preferable. When the curing accelerator is less than the lower limit of 0.05, the resin composition may be insufficiently cured, and when the curing accelerator is greater than the upper limit of 10, the storage stability of the resin composition may be hindered. is there.

(D) Carbon black Carbon black is produced by an oil furnace method, a channel method, an acetylene method, and the like, and has different raw materials and thermal decomposition methods. The primary particles of carbon black are spherical particles having a particle size of about several nm to 500 nm, and the primary particles are connected in a chain shape to form secondary particles (structure). The specific surface area varies depending on the primary particle size and secondary particle structure. In addition, various functional groups such as a carboxyl group and a carbonyl group are present on the surface of carbon black, and the surface exhibits hydrophobicity when not subjected to special treatment. Although the primary particle size, secondary particle structure, and surface state vary depending on the production method, carbon black having an average primary particle size of 10 to 60 nm and a specific surface area of 30 to 400 m ² / g is used in the present invention. More preferably, carbon black having an average primary particle diameter of 20 to 50 nm and a specific surface area of 40 to 300 m ² / g is used. The average particle diameter of the primary particles is obtained, for example, by measuring from an electron micrograph and taking the average. The specific surface area can be determined by a gas adsorption method.

  The compounding quantity of carbon black shall be 1-30 mass parts with respect to 100 mass parts of the sum total of (A) epoxy resin and (B) hardening | curing agent. The blending amount is more preferably 2 to 25 parts by mass, and particularly preferably 5 to 20 parts by mass. When the amount is less than the lower limit (1 part by mass), the conductivity becomes insufficient, and when the amount exceeds the upper limit, the viscosity of the composition becomes high and workability may be deteriorated. In addition, it is preferable that the volume resistivity of the hardened | cured material obtained by measuring at 25 degreeC based on JISK7194: 1994 is 1,000 ohm * cm or less, especially 100 ohm * cm or less.

Moreover, the compounding quantity of carbon black needs to be 0.5-22 mass% with respect to the whole resin composition not only in the range of the said mass part. 1-20 mass% is preferable and, as for the compounding quantity of carbon black, it is especially preferable that it is 2-15 mass%. If it is less than 0.5% by mass, the conductivity is low, and if it exceeds 22% by mass, the fluidity is lowered. In addition to carbon black having an average primary particle size of 10 to 60 nm and a specific surface area of 30 to 400 m ² / g, carbon black having an average particle size and specific surface area outside the above range, and carbon-based carbon nanotubes and the like The material may be blended, but the blending amount is preferably such that the physical properties such as conductivity and viscosity are not lowered. It is not preferable to use a metal filler such as a silver filler or a copper filler because the stable electrical characteristics are impaired.

(E) Thermoplastic resin particles that are solid at 25 ° C. The thermoplastic resin particles that are solid at 25 ° C. used in the present invention may be known thermoplastic resin particles. Examples of the resin include AAS resin, AES resin, AS resin, ABS resin, MBS resin, vinyl chloride resin, vinyl acetate resin, methacrylic resin, phenoxy resin, polybutadiene resin, various fluororesins, various silicone resins, polyacetal, various polyamides, polyamideimide, polyimide, Polyetherimide, polyetheretherketone, polyethylene, polyethylene oxide, polyethylene terephthalate, polycarbonate, polystyrene, polysulfone, polyethersulfone, polyvinyl alcohol, polyvinyl ether, polyvinyl butyral, polyvinyl formal , Poniphenylene ether, polyphenylene sulfide, polybutylene terephthalate, polypropylene, polymethylpentene, or a copolymer thereof. Among these, it is preferable that it is at least 1 sort (s) selected from an acrylic resin, a methacryl resin, a phenoxy resin, a butadiene resin, a polystyrene resin, or these copolymers. Moreover, the particle | grains of the core shell structure from which resin differs in the inner core (core) part and outer skin | shell (shell) part of particle | grains may be sufficient. In that case, the core is preferably rubber particles made of silicone resin, fluororesin, butadiene resin, or the like, and the shell is preferably the above-mentioned various thermoplastic resins made of linear molecular chains. When the thermoplastic resin particles absorb and swell part of at least one of the components (A), (B), or (C) during heating, the liquid conductive resin composition of the present invention gels.

  The thermoplastic resin particles may have a substantially spherical shape, a cylindrical shape, a prismatic shape, an indeterminate shape, a crushed shape, a scale shape, or the like, but a substantially spherical shape and an indeterminate shape having no acute angle portion are preferable for adhesive use. The average particle diameter of the thermoplastic resin particles is appropriately selected depending on the application, but usually the maximum particle diameter (d99: 99% cumulative diameter) is preferably 10 μm or less, and particularly preferably 5 μm or less. Is preferably 0.1 to 5 μm, particularly preferably 0.1 to 2 μm. When the maximum particle size is larger than the above upper limit value or the average particle size is larger than the above upper limit value, a part of the particle thermoplastic resin remains without being sufficiently swollen, and the gelation at the time of heating becomes insufficient. There exists a possibility that the physical property of the composition after hardening may become non-uniform | heterogenous. On the other hand, when the average particle size is smaller than the lower limit, the viscosity of the composition is increased, and workability may be significantly deteriorated. In the present invention, the average particle diameter of the thermoplastic resin particles means a weight average particle diameter. In addition, in this-application specification, 100 places were measured by 2,000 times using the electron microscope, the average value was computed, and the average particle diameter of this thermoplastic resin particle was calculated | required.

  The thermoplastic resin may have a crosslinked structure. However, since it is preferable to form a structure in which the thermoplastic resin is uniformly dispersed in the network structure of the epoxy resin, it is preferable that the degree of crosslinking is low, and that having a linear molecular chain without crosslinking is more preferable.

  The thermoplastic resin particles may have an appropriate molecular weight depending on the type of resin, and those having a polystyrene-equivalent number average molecular weight of 1,000 to 10,000,000 are preferred. Those having a weight average molecular weight of 10,000 to 100,000,000 are preferred, and those having a weight average molecular weight of 100,000 to 1,000,000 are more preferred. When the number average molecular weight is smaller than the lower limit value or the weight average molecular weight is smaller than the lower limit value, the swelling temperature becomes too low, and the stability of the composition may be deteriorated. On the other hand, when the number average molecular weight is larger than the above upper limit value or the weight average molecular weight is larger than the above upper limit value, the temperature for swelling becomes high, and there is a possibility that the volume resistance becomes high without swelling sufficiently. The average molecular weight (average polymerization degree) can be determined, for example, as a number average value or a weight average value in terms of polystyrene in GPC (gel permeation chromatography) analysis using toluene, tetrahydrofuran, acetone or the like as a developing solvent. In addition, the number average molecular weight in this application and a weight average molecular weight are the values calculated | required on the following conditions.

[Measurement condition]
Developing solvent: THF
Flow rate: 200 mL / min
Detector: Differential refractive index detector (RI)
Column: TSKGEL SuperHZ2000 × 1
TSKGEL SuperHZ3000 × 1
TSKGEL SuperHZ4000 × 1
(Both manufactured by TOSOH)
Column temperature: 40 ° C
GPC device: HLC-8220 GPC (manufactured by TOSOH)
Sample injection amount: 5 μL (0.2 wt% THF solution)

  The blending amount of the thermoplastic resin particles is preferably 1 to 50 parts by mass with respect to 100 parts by mass of the total of the component (A) and the component (B) in order to obtain a low volume resistance value. -30 mass parts is more preferable, and 5-20 mass parts is still more preferable. When the content of the thermoplastic resin is less than the lower limit, the thermoplastic resin particles do not swell sufficiently when heated, and the contact between the carbon blacks is hindered, and a low volume resistance value may not be obtained. Even when the content is higher than the upper limit, the swelling of the thermoplastic resin particles is hindered, the contact between the carbon black powders is hindered, and a low volume resistance value may not be obtained. In addition, the viscosity may increase and workability may be deteriorated.

  The composition of the present invention is characterized in that, by heating the composition, the average particle size of the thermoplastic resin particles is 1.5 times or more of the average particle size before heating, preferably 2 times or more. It is. The upper limit of the average particle size of the thermosetting resin particles after heating is preferably 4 times the average particle size before heating, and particularly preferably 3.5 times. This is because when the composition is heated, the thermoplastic resin particles contained in the composition absorb and swell at least one of the components (A) to (C). In particular, the composition has a temperature in the range of 40 ° C. to 200 ° C. for a time in the range of 1 minute to 3 hours, more preferably a temperature in the range of 125 ° C. to 165 ° C. By heating the product, it is preferable that the average particle size of the thermoplastic resin particles after heating is 1.5 times or more, particularly 2 times or more than the average particle size before heating. The heating may be the same step as the heating for curing the composition or the B-stage, or may be a separate step. The average particle diameter of the thermoplastic resin particles after heating can be measured, for example, by observing the surface of the cured product with an electron microscope.

If necessary, the composition of the present invention may contain the following components.
(F) Inorganic filler (F) As an inorganic filler of component (F), for example, silicates such as talc, fired clay, unfired clay, mica, glass, titanium oxide, alumina, fused silica (fused spherical silica, fused Crushed silica), oxides such as silica powder such as synthetic silica and crystalline silica, carbonates such as calcium carbonate, magnesium carbonate and hydrotalcite, hydroxides such as aluminum hydroxide, magnesium hydroxide and calcium hydroxide, sulfuric acid Sulphate or sulfite such as barium, calcium sulfate, calcium sulfite, zinc borate, barium metaborate, borate such as aluminum borate, calcium borate, sodium borate, aluminum nitride, boron nitride, silicon nitride A nitride or the like can be used. These inorganic fillers may be used alone or in combination. Among these, fused silica, crystalline silica, and synthetic silica powder are preferable because the heat resistance, moisture resistance, strength, and the like of the resin composition can be improved. The shape of the inorganic filler is not particularly limited, but the shape is preferably spherical from the viewpoint of viscosity and flow characteristics. Moreover, when using the said inorganic filler, the average particle diameter is although it does not specifically limit, 0.1-30 micrometers is preferable and especially 0.2-8 micrometers is preferable. When the average particle size is less than the lower limit, the viscosity of the resin composition increases, and there is a possibility that poor adhesion due to a decrease in wettability with the base material and workability may deteriorate. When the upper limit is exceeded, there is a concern that the adhesive strength is reduced or the substrate to be bonded is damaged.

  The blending amount of the inorganic filler is preferably 0 to 400 parts by mass, particularly preferably 0 to 300 parts by mass with respect to 100 parts by mass as a total of (A) the epoxy resin and (B) the curing agent. When the upper limit is exceeded, the viscosity of the composition increases, which may result in poor adhesion due to a decrease in wettability with the substrate and workability.

(G) Other components In addition to the above components, the composition of the present invention includes a silane coupling agent, a flame retardant, an ion trap agent, a wax, a colorant, an adhesion aid, and the like according to the purpose. Can be added in an amount that does not interfere with.

  Examples of the silane coupling agent include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, γ- Methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-acryloxypropyltrimethoxysilane, N-β (aminoethyl) ) Γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-amino Propyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropyltrimethoxysilane, bis (triethoxypropyl) tetrasulfide, γ-isocyanatopropyltriethoxysilane, etc. Is mentioned. These can be used singly or in combination of two or more. Among these, it is preferable to use γ-glycidoxypropyltrimethoxysilane. When the coupling agent is used, the amount used is preferably 0.1 to 5.0 parts by mass, and preferably 0.3 to 3 with respect to 100 parts by mass in total of the component (A) and the component (B). 0.0 part by mass is more preferable. By adding the silane coupling agent, the effect of improving the adhesion to the substrate can be obtained.

Method for Preparing Liquid Conductive Resin Composition The liquid conductive resin composition of the present invention can be prepared by mixing the above-described components using a known mixing method, for example, a mixer, a roll, or the like. .

According to the E-type viscometer of the liquid conductive resin composition of the present invention, the viscosity at a shear rate of 2.00 (sec ⁻¹ ) at 25 ° C. is ^{1 to} 300 Pa · s, particularly 10 to 150 Pa · s. Good. If the viscosity exceeds the above upper limit value, wettability between the liquid conductive resin composition and the substrate is deteriorated, which causes voids and poor adhesion, which is not preferable. Moreover, if it is less than the said lower limit, since the liquid dripping at the time of application | coating and sedimentation of an inorganic filler will arise, it is not preferable.

  The liquid conductive resin composition of the present invention can be used as a conductive adhesive material in an electronic device or a semiconductor package. For example, it can be suitably used as a die bond material, a heat sink adhesive, or a lid seal material. it can. The use mode may be performed using a conventionally known method or apparatus. Typical curing conditions are temperatures in the range of 100 ° C. to 200 ° C., preferably 120 to 180 ° C., for a time in the range of 1 hour to 8 hours, preferably 1.5 to 4 hours. In addition, you may perform hardening of a liquid conductive resin composition simultaneously with the resin sealing process of an electronic device or a semiconductor package.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

Examples 1-3 and Comparative Examples 1-6
Each component shown below was mix | blended with the compounding quantity shown in Table 1, mixed with the planetary mixer, after passing 3 rolls, it mixed again with the planetary mixer, and each composition was prepared. These steps were performed at 25 ° C.

(A) Epoxy resin (A-1) Bisphenol F type epoxy resin Product name: YDF-8170C, epoxy equivalent 160 g / eq, liquid at room temperature (25 ° C.) (viscosity 1.5 Pa · s) (manufactured by Nippon Steel Chemical)

(B) Curing agent (B-1) Liquid phenol novolac type resin Product name: MEH-8000H, phenol equivalent 141 g / eq, liquid at room temperature (25 ° C.) (viscosity 2.5 Pa · s) (Maywa Kasei)

(C) Curing accelerator (C-1) 2-Phenyl-4-methyl-5-hydroxymethylimidazole Product name: 2E4MHZ-PW (manufactured by Shikoku Chemicals)

(D) Carbon black or conductive filler (D-1) Carbon black Product name: Mitsubishi carbon black # 2600 Primary particle average particle diameter 13 nm, specific surface area 370 m ² / g (manufactured by Mitsubishi Chemical Corporation)
(D-2) Carbon Black Product name: Mitsubishi Carbon Black # 3230B Average primary particle diameter 23 nm, specific surface area 220 m ² / g (manufactured by Mitsubishi Chemical Corporation)
(D-3) Carbon black Product name: DENKA BLACK Li-100 Primary particle average particle size 35 nm, specific surface area 68 m ² / g (manufactured by Denka)
(D-4) Carbon Black Product Name: Talker Black # 4400 Primary particle average particle size 38 nm, specific surface area 50 m ² / g (manufactured by Timcal)
(D-5) Carbon black Product name: Ensaco 250G primary particle average particle size 45 nm, specific surface area 65 m ² / g (manufactured by Timcal)
(D-6) Carbon black Product name: Asahi # 60 Primary particle average particle size 43 nm, specific surface area 43 m ² / g (Asahi Carbon Co., Ltd.)
(D-7) Carbon black Product name: Asahi # 55 Primary particle average particle size 66 nm, specific surface area 26 m ² / g (manufactured by Asahi Carbon Co., Ltd.)
(D-8) Carbon black Product name: SB235 primary particle average particle size 78 nm, specific surface area 23 m ² / g (Asahi Carbon Co., Ltd.)
(D-9) Carbon black Product name: Ketjen black EC300J Primary particle average particle size of 39 nm, specific surface area of 800 m ² / g (manufactured by Lion Specialty Chemicals)
(D-10) Silver powder Product name: AgC-237 Weight average particle diameter 7 μm, specific surface area 0.35 m ² / g (manufactured by Fukuda Metal Foil Powder Industry Co., Ltd.)
(D-11) Copper powder Product name: Cu-HQW 5 μm Weight average particle diameter 5 μm, Specific surface area 0.2 m ² / g (Fukuda Metal Foil Powder Co., Ltd.)

(E) Thermoplastic resin particles (E-1) Polymethyl methacrylate Product name: FMA403: Average particle size 10 μm, Maximum particle size (d99) 30 μm (Fujikura Kasei Co., Ltd.)

(F) Inorganic filler (F-1) Silica Product name: SO-25R, spherical, mass average particle size 0.5 μm (manufactured by Admatechs)

(G) Other components (G-1) Silane coupling agent: γ-glycidoxypropyltrimethoxysilane (trade name: KBM403 (manufactured by Shin-Etsu Chemical Co., Ltd.))
(G-2) Solvent: Diethylene glycol monoethyl ether (trade name: EDGAC (manufactured by Daicel Chemical Industries))
(G-3) Reactive diluent: Polyethylene glycol diglycidyl ether, epoxy equivalent 268, liquid at room temperature (25 ° C.) (viscosity 0.07 Pa · s) (trade name: Denacol EX830 (manufactured by Nagase ChemteX Corporation))

  Each composition was subjected to the following tests. The results are shown in Table 1.

Test method (a) Confirmation of gelation after heating each composition at 120 ° C. for 10 minutes 10 grams of each resin composition was injected into an aluminum petri dish having a diameter of 5 centimeters and 1 centimeter. After heating for minutes, the petri dish was confirmed to be gelled by allowing the resin composition not to drip for 10 minutes with the petri dish opening facing downward.
In Table 1, the case where it gelled was shown as O, and the case where it did not gel was shown as x.

(B) Viscosity For each composition, according to JIS Z8803: 2011, using an E-type viscometer (HBDV-III, manufactured by Brookfield), measurement temperature 25 ° C., shear rate 2.00 (sec ⁻¹ ), The viscosity at 2 minutes after the start of rotation was measured.

(C) Void of hardened | cured material 5 mg of each composition was apply | coated on the transparent glass plate. Furthermore, each composition was pinched | interposed with the transparent glass plate which affixed the polyimide tape of 50 micrometers thickness, and it fixed with the clip. The resin was cured in a condition of 170 ° C. × 4 hours with a resin sandwiched in a 50 μm gap. The cured product was observed over a 0.5 mm square range with an optical microscope (VHX-2000, manufactured by Keyence Corporation) through the glass, and the number of voids was counted.

(D) Volume resistivity of cured product Based on JIS K7194: 1994, for each cured product cured at 170 ° C. for 4 hours, a resistivity meter (trade name: MCP-T700, Mitsubishi Chemical Analytech Co., Ltd.) Volume resistivity at a measurement temperature of 25 ° C. was measured by a four-probe method.

(E) Volume resistivity after high-temperature storage of the cured product (d) The cured product prepared in the volume resistivity test is stored in an oven set at 150 ° C. for 24 hours, and the volume resistivity after storage is determined according to JIS K7194: 1994. Based on this, a resistivity meter (trade name: MCP-T700, manufactured by Mitsubishi Chemical Analytech Co., Ltd.) was used to measure at a measurement temperature of 25 ° C. by the four-probe method.

(F) Migration test Each composition was printed on a quartz plate in a comb shape as shown in FIG. 1 and cured under curing conditions at 170 ° C. for 4 hours. The line width of the cured product printed in a comb shape is 200 μm, and the distance between the cured products printed in a line shape is 500 μm. A terminal is connected to the portions 1 and 2 in FIG. 1, a DC voltage of 50 V is applied in an environment of 85 ° C. and a relative humidity of 85%, and the time until the insulation resistance value becomes 1 × 10 ⁶ Ω or less is measured. .

  The liquid conductive resin composition of the present invention has stable electrical characteristics even under high temperature and high humidity, and has a low viscosity. Therefore, the liquid conductive resin composition has excellent workability such as dispensing and printing, and has conductivity in an electronic device or semiconductor package. It can be suitably used as an adhesive material. Furthermore, the liquid conductive resin composition of the present invention does not require a solvent or a reactive diluent, and an electronic component having high adhesion and high reliability can be obtained by using the composition as an adhesive.

Claims (9)

The liquid conductive resin composition containing the following (A)-(E) component.
(A) Liquid epoxy resin at 25 ° C. (B) Curing agent liquid at 25 ° C. having one or more phenolic hydroxyl groups in the molecule (A) Phenol in component (B) relative to 1 equivalent of epoxy group in component (C) Curing Accelerator (A) 0.05 to 10 parts by mass (D) primary with respect to a total of 100 parts by mass of component (A) and component (B) Carbon black having an average particle diameter of 10 to 60 nm and a specific surface area of 30 to 400 m ² / g 1 to 30 parts by mass and a resin with respect to 100 parts by mass in total of component (A) and component (B) The proportion of the whole composition is 0.5 to 22% by mass
(E) Thermoplastic resin particles that are solid at 25 ° C. The proportion of 1 to 50 parts by mass and the total resin composition is 0.5 to 30 parts by mass with respect to 100 parts by mass in total of the components (A) and (B). %   The liquid conductive resin composition according to claim 1, further comprising (F) an inorganic filler.   The polystyrene-equivalent molecular weight measured by GPC of component (E) is 1,000 to 10,000,000 in terms of number average molecular weight, and the weight average molecular weight is 10,000 to 100,000,000. Or the liquid conductive resin composition of 2.   The component (E) is at least one kind of thermoplastic resin particles selected from the group consisting of acrylic resin, methacrylic resin, phenoxy resin, butadiene resin, polystyrene resin and copolymers thereof. 2. The liquid conductive resin composition according to item 1.   (E) The liquid conductive resin composition according to any one of claims 1 to 4, wherein the thermoplastic resin particles are formed from linear molecular chains.   The liquid conductive resin composition according to any one of claims 1 to 5, which contains neither a solvent nor a reactive diluent. The liquid conductive resin composition according to any one of claims 1 to 6, wherein a viscosity at a shear rate of 2.00 (sec ^-1 ) is ^{1 to} 300 Pa · s at 25 ° C by an E-type viscometer.   The gelled product of the liquid conductive resin composition according to any one of claims 1 to 7.   The electronic component which has the hardened | cured material of the liquid conductive resin composition of any one of Claims 1-7 as an adhesive agent.