JP2000285730A - Circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a circuit board which uses an adhesive having a low hygroscopic property and high heat resistance. SOLUTION: A first circuit member having a first connecting terminal and a second circuit member having a second connecting terminal are arranged with first and second connecting terminals facing each other, and an adhesive is provided between the first and second connecting terminals arranged face to face and is heated and pressed to electrically connect the oppositely arranged first and second connecting terminals together in this circuit board. The adhesive contains at least a three-dimensional cross-linking resin and a thermoplastic resin having the water absorption coefficient of 0.05-O.25 wt.% and the glass transition temperature of 110-160 deg.C. The thermoplastic resin is a special polysulfone resin and preferably dissolved in an aromatic hydrocarbon solvent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit board for fixing a semiconductor chip to a substrate by an adhesive, for example, by a flip chip mounting method, and for electrically connecting both electrodes.

[0002]

2. Description of the Related Art At present, organic materials such as epoxy resins are widely used in the semiconductor field. In the field of encapsulants, over 90% of encapsulation systems have been replaced by resin encapsulation systems. The sealing material is a composite material composed of an epoxy resin, a curing agent, various additives, an inorganic filler, and the like. As the epoxy resin, a cresol novolac epoxy resin is often used. However, the cresol novolak type epoxy resin does not have the required characteristics such as low water absorption and low elasticity, so that it is difficult to cope with the surface mounting method. For this reason, many new high-performance epoxy resins have been proposed and commercialized. In addition, a silver paste obtained by kneading silver powder with an epoxy resin is often used as a conductive adhesive for die bonding. However, as the mounting method of the semiconductor element on the wiring board shifts to the surface mounting method, there is an increasing demand for improving the solder reflow resistance of the silver paste. In order to solve this problem, improvements have been made to the void, peel strength, water absorption, elastic modulus, etc. of the cured die bonding adhesive layer. In the semiconductor packaging field, cost reduction
Flip-chip mounting, in which an IC chip is directly mounted on a printed circuit board or a flexible wiring board, has attracted attention as a new mounting mode corresponding to high definition. As a flip-chip mounting method, a method of providing a solder bump on a terminal of a chip and performing solder connection or a method of performing electrical connection via a conductive adhesive is known. In these systems, there is a problem that stress based on a difference in thermal expansion coefficient between a chip and a substrate to be connected is generated at a connection interface when exposed to various environments, and connection reliability is reduced. For this reason, a method of injecting an epoxy resin-based underfill material into a gap between a chip and a substrate is generally studied for the purpose of reducing stress at a connection interface. However, the underfill injection step has a problem that the process is complicated and disadvantageous in productivity and cost. In order to solve such a problem, flip-chip mounting using an anisotropic conductive adhesive having anisotropic conductivity and a sealing function has recently attracted attention from the viewpoint of process simplicity.

[0003]

When a chip is mounted on a substrate via an anisotropic conductive adhesive, the adhesive force between the adhesive and the chip or between the adhesive and the substrate decreases under moisture absorbing conditions.
Furthermore, under the temperature cycle condition, stress based on the difference in thermal expansion coefficient between the chip and the substrate is generated in the connection portion. Therefore, when a reliability test such as a thermal shock test, a PCT test, and a high temperature and high humidity test is performed, an increase in connection resistance may occur. There is a problem that peeling of the adhesive occurs. In addition, since the semiconductor package is subjected to a solder reflow temperature test after absorbing moisture in a high-temperature and high-humidity test, the moisture absorbed in the adhesive rapidly expands, thereby causing an increase in connection resistance and peeling of the adhesive. There's a problem. In general, a technique of dispersing a liquid rubber, a crosslinked rubber, and core-shell type rubber particles for the purpose of relaxing the internal stress of the epoxy resin and increasing the toughness is known.
However, it is known that a cured product obtained by dispersing a rubber in an epoxy resin has a lower softening point temperature (or glass transition temperature, hereinafter referred to as Tg) than a cured product of an epoxy resin alone, and has a high heat resistance. In fields where is required, reliability may be reduced. On the other hand, increasing the crosslink density of the epoxy resin to improve Tg in the rubber dispersion system reduces the effect of rubber dispersion, increases the brittleness of the cured product, increases the water absorption rate, and decreases the reliability. This can cause As a method for toughening an epoxy resin without lowering Tg, blending with a highly heat-resistant thermoplastic resin known as an engineering plastic is known. However, in general, these engineering plastics are soluble in a solvent. Because it is poor, the compounding with the epoxy resin is based on the kneading of the powder, it is difficult to form a fine powder of engineering plastic, and it is difficult to disperse it uniformly, and the physical properties are difficult depending on the location It is unsuitable for application to adhesives, such as poor uniformity. The present invention provides a circuit board using an adhesive having low moisture absorption and high heat resistance.The thermoplastic resin used has low water absorption, and is dissolved in a hydrocarbon solvent to form a film from a varnish state. By applying an adhesive that can be used as an adhesive and has a high Tg and can be uniformly mixed or dispersed in the three-dimensional crosslinkable resin, there is no increase in connection resistance at the connection portion and no peeling of the adhesive, and the connection reliability is high. It is an object of the present invention to provide a circuit board having a significantly improved performance.

[0004]

A circuit board according to the present invention comprises a first circuit member having a first connection terminal and a second circuit member having a second connection terminal. And a second connection terminal are disposed facing each other, an adhesive is interposed between the first connection terminal and the second connection terminal disposed opposite to each other, and the first connection terminal disposed oppositely by applying heat and pressure. And a second connection terminal electrically connected to the circuit board, wherein the adhesive is at least a three-dimensional crosslinkable resin and a water absorption of 0.05 to
0.25% by weight and glass transition temperature 110 ° C to 160 ° C
Characterized in that it is an adhesive containing a thermoplastic resin.
Further, the present invention is a circuit board in which the thermoplastic resin having a water absorption of 0.05 to 0.25% by weight and a glass transition temperature of 110 ° C to 160 ° C is a polysulfone resin represented by the following general formula (I). .

[0005]

Embedded image (Here, R ₁ is a hydrogen atom or an alkyl group having 1 to 2 carbon atoms, R ₂ is a linear or branched alkyl group having 4 to 13 carbon atoms, and n is an integer of 5 to 750. )

Further, the present invention is a circuit board in which the thermoplastic resin is preferably soluble in an aromatic hydrocarbon solvent. The circuit board is preferably a resin in which the three-dimensional crosslinkable resin is at least an epoxy resin and contains a latent curing agent. Furthermore, the present invention includes a polysulfone resin in which the adhesive is dissolved in at least an aromatic hydrocarbon solvent, an epoxy resin, a latent curing agent, a radical polymerizable substance, a curing agent that generates free radicals by light irradiation or heating. It is a preferred circuit board to include a combination. Examples of the combination include a combination of an epoxy resin and a latent curing agent, a combination of an epoxy resin and a curing agent that generates free radicals by light irradiation or heating, a combination of a radical polymerizable substance and a latent curing agent, and a combination of a radical polymerizable substance and a light A combination of a curing agent that generates free radicals by irradiation or heating, a combination of an epoxy resin, a radical polymerizable substance, and a latent curing agent, a combination of an epoxy resin, a radical polymerized substance, and a curing agent that generates free radicals by light irradiation or heating Examples of the combination include a combination of an epoxy resin, a latent curing agent, a radical polymerizable substance, and a curing agent that generates free radicals by light irradiation or heating. Further, the present invention is a circuit board in which the adhesive is preferably in the form of a film. It is a preferable circuit board that the conductive particles are dispersed in the adhesive in an amount of 0.1 to 20% by volume.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Circuit members used in the present invention include a semiconductor chip, a printed circuit board, and a flexible wiring board based on polyimide or polyester. On the electrode pads of the semiconductor chip and the substrate, the bumps formed by plating and the tips of the gold wires are melted with a torch or the like to form gold balls, and the balls are pressed on the electrode pads, and then the wires are cut. A protruding electrode such as a wire bump obtained by the above method can be provided and used as a connection terminal.

The thermoplastic resin in the adhesive used in the present invention has a water absorption of 0.05 to 0.25% by weight and a glass transition temperature of 110 to 160 ° C., and is represented by the following general formula (I). A polysulfone resin which is dissolved in an aromatic hydrocarbon solvent is used.

The above-mentioned polysulfone resin is, for example,
It can be synthesized from a bisphenol compound and bis (4-halogenated phenyl) sulfone. As the bisphenol compound, 1,1- (4,4′-dihydroxydiphenyl) -3-methylbutane (in the general formula (I),
₁ is a hydrogen atom, R ₂ is a branched alkyl group having 4 carbon atoms),
2,2- (4,4'-dihydroxydiphenyl) -4-
Methylpentane (R ₁ is an alkyl group having 1 carbon atom, R ₂ is a branched alkyl group having 4 carbon atoms), 1,1- (4,4′-
Dihydroxydiphenyl) -3-ethylhexane (R ₁
Is a hydrogen atom, R ₂ is a branched alkyl group having 7 carbon atoms),
3,3- (4,4′-dihydroxydiphenyl) pentane (R ₁ is an alkyl group having 2 carbon atoms, R ₂ is an alkyl group having 2 carbon atoms), 2,2- (4,4′-dihydroxydiphenyl) heptane (R ₁ is an alkyl group having 1 carbon atom, R ₂ is a linear alkyl group having 5 carbon atoms), 1,1- (4,4′-dihydroxydiphenyl) heptane (R ₁ is a hydrogen atom, R ₂ is a carbon atom A linear alkyl group of the formula 6), 2,2- (4,4′-
Dihydroxydiphenyl) octane (R ₁ is an alkyl group having 1 carbon atom, R ₂ is a linear alkyl group having 6 carbon atoms),
1,1- (4,4′-dihydroxydiphenyl) octane (R ₁ is an alkyl group having 1 carbon atom, R ₂ is a linear alkyl group having 6 carbon atoms), 2,2 (4,4′-dihydroxydiphenyl) ) Nonane (R ₁ is an alkyl group having 1 carbon atom, R ₂ is a linear alkyl group having 7 carbon atoms), 1,1- (4,4′-dihydroxydiphenyl) nonane (R ₁ is an alkyl group having 1 carbon atom) R ₂ is a linear alkyl group having 8 carbon atoms), 2,2
-(4,4'-dihydroxydiphenyl) decane (R ₁
Is an alkyl group having 1 carbon atom, R ₂ is a linear alkyl group having 8 carbon atoms), 1,1- (4,4′-dihydroxydiphenyl) decane (R ₁ is a hydrogen atom, and R ₂ is Linear alkyl group), 2,2- (4,4′-dihydroxydiphenyl) undecane (R ₁ is an alkyl group having 1 carbon atom, R ₂ is a linear alkyl group having 9 carbon atoms), 1,1- (4,4'-
Dihydroxydiphenyl) undecane (R ₁ is a hydrogen atom, R ₂ is a linear alkyl group having 10 carbon atoms), 2,2-
(4,4′-dihydroxydiphenyl) dodecane (R ₁
Is an alkyl group having 1 carbon atom, R ₂ is a linear alkyl group having 10 carbon atoms), 1,1- (4,4′-dihydroxydiphenyl) dodecane (R ₁ is a hydrogen atom, and R ₂ is an alkyl group having 11 carbon atoms). A linear alkyl group), 2,2- (4,4′-dihydroxydiphenyl) tridecane (R ₁ is an alkyl group having 1 carbon atom, R ₂ is a linear alkyl group having 11 carbon atoms), 1,1-
(4,4'-dihydroxydiphenyl) tridecane (R
₁ is a hydrogen atom, R ₂ is a linear alkyl group having 12 carbon atoms),
2,2- (4,4′-dihydroxydiphenyl) tetradecane (R ₁ is an alkyl group having 1 carbon atom, R ₂ is an alkyl group having 12 carbon atoms)
Linear alkyl group), 1,1- (4,4′-dihydroxydiphenyl) tetradecane (R ₁ is a hydrogen atom, R ₂ is a linear alkyl group having 13 carbon atoms), and 2,2- (4 ,
4′-dihydroxydiphenyl) pentadecane (R ₁ is an alkyl group having 1 carbon atom, R ₂ is a linear alkyl group having 13 carbon atoms), and two or more of these may be mixed. Preferably, 2,2- (4,4′-dihydroxydiphenyl) octane (R ₁ is an alkyl group having 1 carbon atom, R ₂ is a linear alkyl group having 6 carbon atoms), 1,1-
(4,4′-dihydroxydiphenyl) decane (R ₁ is a hydrogen atom, R ₂ is a linear alkyl group having 9 carbon atoms) is used. As the bis (4-halogenated phenyl) sulfone for synthesizing the polysulfone resin, bis (4-chlorophenyl) propane is exemplified. Furthermore, a bisphenol compound halide and bis (4-
It can also be synthesized from (hydroxyphenyl) sulfone.

The polysulfone resin can be synthesized by a usual method such as a solution polymerization method. For example, in the case of the solution polymerization method, a solvent in which the produced polysulfone resin is dissolved,
For example, a bisphenol compound and bis (4-halogenated phenyl) are dissolved in dimethylacetamide or the like, and the solution is dissolved at 130 ° C. in the presence of a base such as sodium hydroxide or potassium carbonate.
The reaction is carried out at -180 ° C for 10-12 hours to synthesize the desired polysulfone resin.

The polysulfone resin of the present invention preferably has a molecular weight, as measured by gel permeation chromatography using tetrahydrofuran as a solvent, of 20,000 to 300,000 in terms of polystyrene for the purpose of imparting toughness to the adhesive. . If it is less than 20,000, the cured product may not be brittle, and if it is more than 300,000, the fluidity of the resin composition decreases. Therefore, when the connection terminal of the electronic member is connected to the connection terminal of the circuit board, the electronic component and the circuit are connected. Filling with an adhesive resin between the substrates becomes difficult.

The three-dimensional crosslinkable resin used in the present invention comprises:
Epoxy resins, cyanate ester resins, imide resins, acrylate / methacrylate / maleimide compounds, and the like are used together with a curing agent. In the case of an epoxy resin, a known imidazole-based, hydrazide-based, boron trifluoride-amine complex, sulfonium salt, amine imide, polyamine salt, dicyandiamide, or other curing agent or a mixture thereof is used as a curing agent. Bisphenol type epoxy resin derived from bisphenol A, F, S, AD, etc., phenol novolak, epoxy novolak type resin derived from cresol novolak, naphthalene type epoxy resin having naphthalene skeleton, glycidylamine type epoxy resin, glycidyl ether type Epoxy resins, various epoxy compounds having two or more glycidyl groups in one molecule, such as biphenyl and alicyclic, and other known epoxy resins are used alone or as a mixture. It is preferable to use a high-purity product in which alkali metal ions, alkaline earth metal ions, halogen ions, particularly chlorine ions and hydrolyzable chlorine, etc. are reduced to 300 ppm or less for preventing electromigration and corrosion of wiring metal. .

As the cyanate ester resin, bis (4-cyanatophenyl) ethane, 2,2-bis (4-
Cyanatophenyl) propane, 2,2-bis (3,5-
Dimethyl-4-cyanatophenyl) methane, 2,2-bis (4-cyanatophenyl) -1,1,1,3,3,3
-Hexafluoropropane, α, α'-bis (4-cyanatophenyl) -m-diisopropylbenzene, a cyanate esterified product of a phenol-added dicyclopentadiene polymer, or the like, or a prepolymer thereof alone or as a mixture. Used. Among them, 2,2-bis (4-cyanatophenyl) propane, 2,2-bis (3,5-dimethyl-4-cyanatophenyl) and the like are preferable because the cured product has particularly good dielectric properties. Metal-based reaction catalysts are used as a curing agent for the cyanate ester resin, and metal catalysts such as manganese, iron, cobalt, nickel, copper, and zinc are used. Specifically, 2-ethylhexanoate and naphthenic acid are used. It is used as an organic metal salt compound such as a salt and an organic metal complex such as an acetylacetone complex.

The compounding amount of the metal-based reaction catalyst is preferably from 1 to 3000 ppm, more preferably from 1 to 1000 ppm, still more preferably from 2 to 300 ppm, based on the cyanate ester compound.
If the blending amount of the metal-based reaction catalyst is less than 1 ppm, the reactivity and curability tend to be insufficient, and if it exceeds 3000 ppm, the control of the reaction becomes difficult, or the curing tends to be too fast. Absent.

The radical polymerizable substance such as an acrylate / methacrylate / maleimide compound of the three-dimensional crosslinkable resin used in the present invention is a substance having a functional group which is polymerized by a radical. Radical polymerizable substances are monomers,
It is possible to use any state of the oligomer,
It is also possible to use monomers and oligomers in combination. Specific examples of acrylates (methacrylates) include methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, trimethylolpropane triacrylate, tetramethylol methane tetraacrylate, and 2-hydroxy-1. , 3-Diacryloxypropane, 2,2-bis [4- (acryloxymethoxy) phenyl] propane,
Examples thereof include 2,2-bis [4- (acryloxypolyethoxy) phenyl] propane, dicyclopentenyl acrylate, tricyclodecanyl acrylate, and tris (acryloyloxyethyl) isocyanurate. These can be used alone or in combination. If necessary, a polymerization inhibitor such as hydroquinone or methyl ether hydroquinone may be appropriately used. In addition, it is preferable to have a dicyclopentenyl group and / or a tricyclodecanyl group and / or a triazine ring, since heat resistance is improved.

The maleimide compound is a compound containing at least two maleimide groups in the molecule, for example, 1-methyl-2,4-bismaleimidebenzene,
N, N'-m-phenylenebismaleimide, N, N'-
p-phenylenebismaleimide, N, N'-m-toluylenebismaleimide, N, N'-4,4-biphenylenebismaleimide, N, N'-4,4- (3,3'-dimethylbiphenylene) bis Maleimide, N, N'-4,4
-(3,3'-dimethyldiphenylmethane) bismaleimide, N, N'-4,4- (3,3'-diethyldiphenylmethane) bismaleimide, N, N'-4,4-diphenylmethanebismaleimide, N, N '-4,4-diphenylpropanebismaleimide, N, N'-4,4-diphenyletherbismaleimide, N, N'-3,3'
-Diphenylsulfonebismaleimide, 2,2-bis (4- (4-maleimidophenoxy) phenyl) propane, 2,2-bis (3-s-butyl-4,8- (4-maleimidophenoxy) phenyl) propane, 1,1-bis (4- (4-maleimidophenoxy) phenyl) decane, 4,4′-cyclohexylidene-bis (1- (4-
(Maleimidophenoxy) -2-cyclohexylbenzene, 2,2-bis (4- (4-maleimidophenoxy)
Phenyl) hexafluoropropane and the like. These can be used alone or in combination.

As a curing agent for a radical polymerizable substance such as an acrylate / methacrylate / maleimide compound, a mixture of a curing agent that generates free radicals by heat or light is used. Specifically, it is selected from peroxyesters, dialkyl peroxides, hydroperoxides, and silyl peroxides, and is more preferably selected from peroxyesters having high reactivity.
The above-mentioned curing agents can be appropriately mixed and used.

Examples of the peroxyester include cumyl peroxy neodecanoate, 1,1,3,3-tetramethylbutyl peroxy neodecanoate, 1-cyclohexyl-1-methylethyl peroxynodecanoate. , T-hexyl peroxy neodecanoate, t-butyl peroxypivalate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanate,
2,5-dimethyl-2,5-di (2-ethylhexanoylperoxy) hexane, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanate, t
-Hexylperoxy-2-ethylhexanonate, t
-Butylperoxy-2-ethylhexanonate, t-
Butyl peroxyisobutyrate, 1,1-bis (t-
Butylperoxy) cyclohexane, t-hexylperoxyisopropyl monocarbonate, t-butylperoxy-3,5,5-trimethylhexanonate, t-
Butyl peroxylaurate, 2,5-dimethyl-2,
5-Di (m-toluoylperoxy) hexane, t-butylperoxyisopropyl monocarbonate, t-butylperoxy-2-ethylhexyl monocarbonate, t-hexylperoxybenzoate, t-butylperoxyacetate, etc. are used. it can. Examples of the dialkyl peroxide include α, α′bis (t-butylperoxy) diisopropylbenzene, dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, t-butylcum Luper oxide or the like can be used.

Examples of the hydroperoxide include diisopropylbenzene hydroperoxide and cumene hydroperoxide. Examples of the diacyl peroxide include isobutyl peroxide, 2,4-dichlorobenzoyl peroxide, and 3,5,5-trimethylhexa. Noyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, succinic peroxide, benzoylperoxytoluene, benzoyl peroxide and the like can be used. Examples of peroxydicarbonate include di-n-propylperoxydicarbonate, diisopropylperoxydicarbonate, bis (4-t-butylcyclohexyl) peroxydicarbonate, di-2-ethoxymethoxyperoxydicarbonate, di ( 2-ethylhexylperoxy) dicarbonate, dimethoxybutylperoxydicarbonate, di (3-methyl-3-
(Methoxybutylperoxy) dicarbonate and the like can be used.

Examples of peroxyketals include 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-hexylperoxy) cyclohexane, 1,1-bis (T-butylperoxy) -3,3,5-trimethylcyclohexane,
1,1- (t-butylperoxy) cyclododecane,
2,2-bis (t-butylperoxy) decane and the like can be used. Examples of the silyl peroxide include t-butyltrimethylsilyl peroxide, bis (t-butyl) dimethylsilyl peroxide, t-butyltrivinylsilyl peroxide, bis (t-butyl) divinylsilyl peroxide, and tris (t-butyl) vinyl. Silyl peroxide, t-butyl triallyl silyl peroxide, bis (t-butyl) diallylsilyl peroxide, tris (t-butyl) allylsilyl peroxide and the like can be used.

These hardeners generating free radicals can be used alone or as a mixture.
Inhibitors and the like may be mixed and used. A microcapsule obtained by coating the above-mentioned curing agent with a polyurethane-based or polyester-based polymer substance or the like is preferable because the pot life is extended.

The adhesive used for the circuit board of the present invention can be used in a mixing ratio of the polysulfone resin and the three-dimensional crosslinkable resin of 1:99 to 99: 1 by weight, preferably 10:90. ９０90: 10. The adhesive used for the circuit board of the present invention may contain a rubber component such as acrylic rubber for the purpose of reducing the elastic modulus of the cured product. Also,
The adhesive used for the circuit board of the present invention may be blended with a thermoplastic resin such as a phenoxy resin in order to make the film formability easier. In particular, a phenoxy resin is preferable when an epoxy-based resin is used as a base resin, because the phenoxy resin has features such as excellent compatibility with the epoxy resin and excellent adhesiveness since the structure is similar to the epoxy resin.

In order to form the adhesive in the form of a film, the adhesive containing the three-dimensionally crosslinkable resin, the curing agent thereof, and the thermoplastic resin is dissolved or dispersed in an organic solvent to form a varnish.
It is performed by applying the composition on a peelable substrate and removing the solvent at a temperature lower than the activation temperature of the curing agent. In particular, an adhesive composition containing an epoxy resin and a latent curing agent as a three-dimensional crosslinkable resin and a polysulfone resin represented by the general formula (1) as a thermoplastic resin is liquefied by dissolution or dispersion in an organic solvent, It is performed by applying the composition on a peelable substrate and removing the solvent at a temperature lower than the activation temperature of the curing agent. As the solvent used at this time, a mixed solvent of an aromatic hydrocarbon solvent and an oxygen atom-containing organic solvent is preferable because the solubility of the adhesive composition is improved.

In the adhesive used for the circuit board of the present invention, conductive particles are dispersed for the purpose of positively imparting anisotropic conductivity in order to absorb variations in height of chip bumps and substrate electrodes. Can also. In the present invention, the conductive particles are, for example, metal particles of Au, Ni, Ag, Cu, solder, or the like, or metal particles formed by plating or depositing a thin film of gold, palladium, or the like on the surface of these metals, and polystyrene. Ni, Cu, Au,
Conductive particles provided with a conductive layer such as solder can be used. It is necessary that the particle size is smaller than the minimum distance between the electrodes of the substrate, and if there is a height variation of the electrodes, it is preferably larger than the height variation, and preferably larger than the average particle size of the inorganic filler. 1 to 10 μm is preferred. The amount of the conductive particles dispersed in the adhesive is 0.1
-20% by volume, preferably 0.2-15% by volume.

As described above, the adhesive used for the circuit board of the present invention is obtained by dissolving or dispersing each component in an organic solvent.
It can be easily produced by stirring and mixing by an arbitrary method, and can be further applied to a peelable substrate, and a film can be formed by removing the solvent at a temperature lower than the activation temperature of the curing agent. At this time, in addition to the above-mentioned composition, additives used for preparing ordinary epoxy resin compositions may be added. The thickness of the film-like adhesive is not particularly limited, but is preferably larger than the gap between the first and second circuit members, and is generally preferably 5 μm or more larger than the gap.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments. Example 1 A polysulfone resin represented by the general formula (1) was synthesized as follows. 29.8 g of 1,1- (4,4′-dihydroxydiphenyl) undecane and bis (4
-(Chlorophenyl) sulfone (57.4 g) and potassium carbonate (34.5 g) were refluxed in 500 ml of dimethylacetamide at an oil bath temperature of 180 ° C with stirring under a nitrogen atmosphere. After stirring for 12 hours, the mixture was dropped into 3000 ml of acetone, and the formed precipitate was collected by filtration. The precipitate was dissolved in tetrahydrofuran, the insolubles were filtered off, and the filtrate was added dropwise to 3000 ml of methanol. The resulting precipitate was collected by filtration to obtain 83 g of a polysulfone resin. As a result of measurement by GPC, Mn = 46341 and Mw = 3 in terms of polystyrene.
00000, Mw / Mn = 6.58.

The resulting polysulfone resin was dissolved in toluene, applied to a petri dish, and the toluene was volatilized to prepare a cast film. The cast film was cut into 2 cm squares, dried at 100 ° C. under reduced pressure, weighed, immersed in pure water for 24 hours, and then weighed to calculate the weight increase. Was measured for water absorption. As a result of measuring the water absorption, the water absorption of the produced polysulfone resin was 0.12% by weight. Further, the elastic modulus of the cast film was measured using a dynamic viscoelasticity measuring device (heating rate: 5 ° C./min, 10 Hz).
Then, as a result of measuring Tg by the peak value of tan δ, 1
It was 10 ° C.

10 g of the produced polysulfone resin was dissolved in 30 g of toluene to obtain a 25% by weight solution. Next, 18.5 g of a commercially available liquid epoxy resin containing a microcapsule-type latent curing agent (bisphenol F-type epoxy resin, imidazole-based curing agent encapsulated in bisphenol F-type epoxy resin, epoxy equivalent: 185) was added to this solution. , Agitated, and polystyrene core (diameter: 5
μm), a 0.2 μm thick nickel layer is provided on the surface of
Conductive particles having a 0.04 μm thick Au layer formed outside the nickel layer were dispersed at 3% by volume to obtain a varnish solution for film coating. This solution was applied to a separator (silicone-treated polyethylene terephthalate film, thickness 40 μm) with a roll coater as a peelable substrate.
C. for 10 minutes to produce an adhesive film having a thickness of 40 .mu.m. The adhesive film was cured at 150 ° C. for 3 hours, and the elasticity of the cured film was measured using a dynamic viscoelasticity measuring device (heating rate 5 ° C./min, 10 Hz), and Tg was measured by the peak value of tan δ. , Tg was 157 ° C.

Using the produced adhesive film, gold bumps (area: 80 × 80 μm, space 30 μm, height: 1)
Chip with 5 μm, 288 bumps (10 × 10 m)
m, thickness: 0.5 mm) and Ni / Au plated Cu circuit printed circuit board (electrode height: 20 μm, thickness: 0.8 mm)
Was connected as shown below. An adhesive film with a separator was formed in a size of 12 mm × 12 mm, the adhesive film on the opposite side of the separator was laminated on a Ni / Au plated Cu circuit printed board, and a temporary connection step was performed at 60 ° C. and 0.5 MPa. After the temporary connection step, the separator was peeled off. After aligning the bumps on the chip with the Ni / Au-plated Cu circuit printed circuit board, heating and pressing are performed from above the chip under the conditions of 180 ° C., 100 g / bump, and 20 seconds, and the circuit board is formed by the main connection. Obtained.

The connection resistance of the circuit board after this connection is 5 mΩ at maximum per bump, 1.5 mΩ on average, and the insulation resistance is 1
Was 0 ⁸ Ω or more. A large number of such circuit boards were prepared in the same manner, and subjected to a thermal shock test test at −55 to 125 ° C. for 1000 cycles. In addition, a PCT test (121 ° C., 2 atm) was performed for 200 hours, and a solder bath immersion at 260 ° C. was performed for 10 seconds, and the connection resistance was measured in the same manner as described above. 10
There was no change in the value of ⁸ Ω or more, indicating good connection reliability.

(Example 2) The adhesive film with a separator obtained in Example 1 was stored at room temperature for one month.
A chip and a substrate were connected in the same manner as in the above to obtain a circuit board. The connection resistance of the circuit board after connection is up to 7.5 per bump
mΩ, the average was 1.7 mΩ, and the insulation resistance was 10 ⁸ Ω or more. A large number of such circuit boards were produced in the same manner, and
Similarly, the thermal shock test at -55 to 125 ° C was performed for 100 times.
Processing was performed for 0 cycles. PCT test (121 ° C,
2 atm) for 200 hours and 260 ° C solder bath immersion for 1 hour.
The connection resistance was measured in the same manner as above for 0 second, and as a result, the maximum was 8 mΩ / bump, the average was 1.9 mΩ, and the insulation resistance was not changed to a value of 10 ⁸ Ω or more, indicating good connection reliability.

Comparative Example 1 As in Example 1, 10 g of bisphenol S type epoxy resin (epoxy equivalent 306) was used.
18.5 g of a liquid epoxy resin containing a microcapsule-type latent curing agent and 30 g of toluene were added, and 3% by volume of conductive particles having an Au layer formed on the surface of a polystyrene core (average diameter: 5 μm) were mixed and dispersed. However, the bisphenol S-type epoxy resin did not dissolve and a varnish solution for film coating could not be obtained.

Comparative Example 2 In the same manner as in Comparative Example 1, a liquid epoxy resin 18.5 containing 10 g of bisphenol S type epoxy resin and a microcapsule type latent curing agent was used.
g and 30 g of methyl ethyl ketone, and 3% by volume of conductive particles having an Au layer formed on the surface of a polystyrene core (average diameter: 5 μm) were dispersed and mixed to obtain a varnish solution for film coating. This solution was applied to a separator (silicone-treated polyethylene terephthalate film, thickness: 40 μm) as a peelable substrate by a roll coater in the same manner as in Example 1, and dried at 100 ° C. for 10 minutes to produce an adhesive film having a thickness of 40 μm. The adhesive film was cured at 150 ° C. for 3 hours, the elastic modulus of the cured film was measured using a dynamic viscoelasticity measuring apparatus, and Tg was measured by the peak value of tan δ. As a result, Tg was 120 ° C.

Example 1 was prepared using the prepared adhesive film.
Similarly to the above, a chip (10 × 10 mm, thickness: 0.5 mm) with gold bumps (area: 80 × 80 μm, space: 30 μm, height: 15 μm, number of bumps: 288) and Ni / Au
The connection of a plated Cu circuit printed circuit board (electrode height: 20 μm, thickness: 0.8 mm) was performed as shown below. An adhesive film with a separator is formed in a size of 12 mm × 12 mm, and the adhesive film on the opposite side of the separator is laminated on a Ni / Au plated Cu circuit printed board, and the temperature is 60 ° C. and 0.5 MPa.
A temporary connection step was performed. After the temporary connection step, the separator was peeled off. After aligning the bumps on the chip with the Ni / Au plated Cu circuit printed circuit board,
Heating and pressurizing were performed from above the chip under the conditions of g / bump and 20 seconds, and the main connection was performed to obtain a circuit board.

The connection resistance of the circuit board after connection is 6 mΩ at maximum per bump, 1.6 mΩ on average, and the insulation resistance is 10 mΩ.
It was ⁸ Ω or more. A large number of such circuit boards were prepared in the same manner, and subjected to a thermal shock test test at −55 to 125 ° C. for 1000 cycles. In addition, a PCT test (121 ° C., 2 atm) was performed for 200 hours, and a solder bath immersion at 260 ° C. was performed for 10 seconds, and the connection resistance was measured in the same manner as described above. Peeling occurred between printed boards (solder heat resistance), resulting in poor conduction.

Comparative Example 3 After storing the adhesive film with separator obtained in Comparative Example 2 at room temperature for one month, a chip and a substrate were connected in the same manner as in Example 1 to obtain a circuit board. During storage of the adhesive, the curing of the adhesive film progressed, and the fluidity was insufficient, resulting in partial conduction failure.

In Comparative Example 3, it is considered that the capsule of the microcapsule-type latent curing agent was a coating of an epoxy resin and was dissolved in methyl ethyl ketone, resulting in poor storage stability. On the other hand, toluene, which is an aromatic hydrocarbon solvent used in Examples 1 and 2, dissolves the polysulfone resin and can be formed into a film to make the composition uniform. In addition, since the capsule is not dissolved, it is stored at room temperature for one month. After that, the same connection characteristics as in Example 1 were obtained, the storage stability was excellent, the heat resistance was excellent as shown in the thermal shock test and the solder heat resistance, and the moisture absorption and heat resistance were shown in the PCT test. Excellent results were obtained.

[0038]

The circuit board of the present invention has at least a three-dimensionally crosslinkable resin as an adhesive and a water absorption of 0.05 to 0.25.
By containing a thermoplastic resin having a glass transition temperature of 110 ° C. to 160 ° C. by weight, a cured product having good moisture resistance and heat resistance can be obtained, and as a result, connection reliability and storage stability are greatly improved. Can be done.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09J 181/06 C09J 181/06 5G301 201/00 201/00 H01L 23/14 H05K 1/18 J H05K 1 / 18 3/32 B 3/32 H01L 23/14 R (72) Inventor Akira Nagai, Tsudai, Tsukuba, Ibaraki 48 Inside Tsukuba Development Laboratory, Hitachi Chemical Co., Ltd. (72) Inventor Kenzo Takemura 48, Wadai, Tsukuba, Ibaraki F-term in the Tsukuba Development Laboratory, Hitachi Chemical Co., Ltd. FA151 FA152 FA161 FA162 FA191 FA192 GA22 JA09 JB08 JB10 KA03 KA16 KA32 LA02 LA07 LA08 NA20 PA30 PA33 5E319 AA03 AB05 BB12 BB13 BB16 BB20 GG20 5E336 AA04 CC32 CC55 EE07 EE08 GG30 5G301 DA10 DA29 DA42 DA57 DD03 DD08

Claims (7)

[Claims] A first circuit member having a first connection terminal and a second circuit member having a second connection terminal are arranged so that the first connection terminal and the second connection terminal face each other. An adhesive is interposed between the first connection terminal and the second connection terminal disposed opposite to each other, and the first connection terminal and the second connection terminal disposed opposite each other are electrically connected by heating and pressing. Circuit board, wherein the adhesive comprises at least a three-dimensionally crosslinkable resin, a water absorption of 0.05 to 0.25% by weight, and a glass transition temperature of 1%.
A circuit board, which is an adhesive containing a thermoplastic resin at 10 to 160 ° C. 2. The circuit board according to claim 1, wherein the thermoplastic resin of the adhesive according to claim 1 is a polysulfone resin represented by the following general formula (I). Embedded image (Here, R ₁ is a hydrogen atom or an alkyl group having 1 to 2 carbon atoms, R ₂ is a linear or branched alkyl group having 4 to 13 carbon atoms, and n is an integer of 5 to 750. ) 3. The circuit board according to claim 1, wherein the thermoplastic resin is soluble in an aromatic hydrocarbon solvent. 4. The circuit board according to claim 1, wherein the three-dimensional crosslinkable resin is at least an epoxy resin and contains a latent curing agent. 5. A combination of an adhesive containing at least a polysulfone resin soluble in an aromatic hydrocarbon solvent, an epoxy resin, a latent curing agent, a radical polymerizable substance, and a curing agent that generates free radicals by light irradiation or heating. The circuit board according to any one of claims 1 to 4, comprising: 6. The circuit board according to claim 1, wherein the adhesive is in the form of a film. 7. The circuit board according to claim 1, wherein 0.1% to 20% by volume of conductive particles are dispersed in the adhesive.