KR20220061166A - anisotropic conductive film - Google Patents

Abstract

As an anisotropic conductive film for application to mounting on a wiring board of an electronic component, the anisotropic conductive film capable of suppressing an increase in connection resistance without reducing particle trapping efficiency is an epoxy compound, an anion polymerization curing agent, and an acryl-based A compound, a radical polymerization initiator, resin for film-forming, and electrically-conductive particle are contained. Here, content of an acryl-type compound is 1.0 mass % or more and 8.0 mass % or less with respect to the sum total of an epoxy-type compound, an anion polymerization type hardening|curing agent, an acryl-type compound, a radical polymerization initiator, and resin for film-forming. As for the anisotropic conductive film, the 1st layer and 2nd layer each containing an epoxy-type compound, an anion polymerization type hardening|curing agent, and resin for film-forming may be laminated|stacked. In that case, only a 1st layer may contain an acryl-type compound and a radical polymerization initiator, and may also contain electrically-conductive particle further.

Description

anisotropic conductive film

The present invention relates to an anisotropic conductive film.

When an electronic component such as an IC chip is mounted on a wiring board such as a glass substrate, an anisotropic conductive film containing an epoxy resin as a polymerization component capable of realizing high adhesive strength and good water and heat resistance is sometimes used. In such a case, in order to improve the flexibility of the film, acrylic rubber was being added.

However, when acrylic rubber is added, although the flexibility of the anisotropic conductive film is improved, there is a problem in that the adhesion to the polyimide surface exposed at the anisotropic conductive bonding point of the wiring board is reduced. For this reason, with respect to the anisotropic conductive film containing the epoxy resin, after ensuring flexibility even without adding acrylic rubber, in order to improve adhesion to the polyimide surface, an epoxy compound as an anionic polymerizable compound, An anisotropic conductive film containing an on-polymerization curing agent, an acrylic compound as a radically polymerizable compound, a radical polymerization initiator, conductive particles, and a resin for film formation has been proposed (Patent Document 1). In this case, it is carried out to contain about 15 parts by mass of the acrylic compound with respect to 100 parts by mass of the total of the epoxy compound, the anion polymerization type curing agent, the acrylic compound, the radical polymerization initiator, and the resin for film formation ( Example 1 of Patent Document 1).

Japanese Laid-Open Patent Publication No. 2007-224228

However, when the anisotropic conductive connection is performed by thermocompression bonding with the anisotropic conductive film of Patent Document 1, the resin flow is suppressed excessively in the initial stage of thermocompression bonding, the press-fitting of the conductive particles becomes insufficient, and as a result, the connection resistance value rises. I was concerned about the occurrence of the problem that this would cause. Conversely, an attempt to improve the indentation of the conductive particles leads to an excessive flow of the resin, and there is concern about a decrease in the particle trapping efficiency.

The object of the present invention is to mount an anisotropic conductive film containing an epoxy compound, an anion polymerization curing agent, an acryl compound, a radical polymerization initiator, conductive particles, and a film-forming resin on a wiring board when an electronic component is mounted on a wiring board, particle trapping efficiency This is to make it possible to suppress an increase in the connection resistance value without lowering the .

The present inventors, the content of the acrylic compound in the anisotropic conductive film containing an epoxy compound, an anion polymerization curing agent, an acrylic compound, a radical polymerization initiator, a resin for film formation, and conductive particles, an epoxy compound and anion polymerization By making it fall within a specific range with respect to the total of a mold hardening agent, an acrylic compound, a radical polymerization initiator, and resin for film-forming, it discovered that the subject of the above-mentioned invention could be solved, and came to complete this invention.

That is, the present invention is an anisotropic conductive film containing an epoxy compound, an anion polymerization curing agent, an acrylic compound, a radical polymerization initiator, a film-forming resin, and conductive particles, wherein the content of the acrylic compound is an epoxy compound and anionic polymerization The anisotropic conductive film which is 1.0 mass % or more and 8.0 mass % or less with respect to the total of a mold hardening agent, an acrylic compound, a radical polymerization initiator, and resin for film-forming is provided.

Moreover, this invention is the above-mentioned anisotropic conductive film, It is a bonded structure by which a 1st electronic component and a 2nd electronic component are anisotropically conductively connected, It is an anisotropic conductive film mentioned above similarly, A 1st electronic component and a 2nd electron The manufacturing method of the bonded structure which carries out anisotropic conductive connection of components is provided.

The anisotropic conductive film of this invention contains an epoxy compound, an anion polymerization type hardening|curing agent, an acrylic compound, a radical polymerization initiator, resin for film-forming, and electrically conductive particle. This anisotropic conductive film contains an acryl-type compound in the amount used as 1.0 mass % or more and 8.0 mass % or less with respect to the total of an epoxy-type compound, an anion polymerization type hardening|curing agent, an acrylic compound, a radical polymerization initiator, and resin for film-forming. For this reason, by giving priority to radical polymerization reaction over anionic polymerization reaction, while suppressing resin flow moderately, the trapping property of an electrically-conductive particle can be improved. Therefore, when the anisotropic conductive film is applied to the mounting of an electronic component such as an IC chip on a glass substrate or a wiring substrate such as a flexible substrate, good particle trapping properties can be realized and an increase in the connection resistance value can be suppressed. .

Hereinafter, an example of this invention is demonstrated in detail.

<Anisotropic conductive film>

The anisotropic conductive film of this invention contains an epoxy compound, an anion polymerization type hardening|curing agent, an acrylic compound, a radical polymerization initiator, resin for film-forming, and electrically-conductive particle. In this anisotropic conductive film, content of an acrylic compound is 1.0 mass % or more and 8.0 mass % or less with respect to the total of an epoxy compound, an anion polymerization type hardening|curing agent, an acrylic compound, a radical polymerization initiator, and resin for film formation, Preferably 2.0 They are mass % or more and 7.0 mass % or less. For this reason, when giving priority to a radical polymerization reaction rather than an anionic polymerization reaction, while suppressing resin flow moderately at the time of anisotropic electrically conductive connection, the trapping property of an electrically-conductive particle can be improved. Moreover, when content of an acryl-type compound deviates from this range, it is anxious that the resin flow in the initial stage of anisotropic electrically conductive connection will be suppressed excessively, and press-fitting of an electrically-conductive particle will become inadequate.

The minimum layer thickness of the anisotropic conductive film of this invention becomes like this. Preferably it is 3 micrometers or more, More preferably, it is 5 micrometers or more, More preferably, it is set as 8 micrometers or more. The upper limit is 50 µm or less, more preferably 25 µm or less, and still more preferably 20 µm or less. In the case of a multilayer structure of two or more layers, it becomes the total thickness.

Although a single layer structure may be sufficient as the anisotropic conductive film of this invention and the multilayer structure of two or more layers may be sufficient as it, the aspect of the two-layer structure in which the 1st layer and the 2nd layer are laminated|stacked is preferable. In this case, it is preferable that each of a 1st layer and a 2nd layer contains an epoxy-type compound, an anion polymerization type hardening|curing agent, and resin for film-forming. It is in order to advance anionic polymerization in the whole film, and also in order to improve the adhesiveness of a 1st layer and a 2nd layer. Moreover, although an acryl-type compound and a radical polymerization initiator may be contained in both of a 1st layer and a 2nd layer, they may be contained in either one of a 1st layer and a 2nd layer. When the acrylic compound and the radical polymerization initiator are contained in the first layer, it is preferable that the acrylic compound is not contained in the second layer, but the radical polymerization initiator may be contained in the second layer. In addition, although an electrically-conductive particle may be contained in both a 1st layer and a 2nd layer, when the layer containing an acryl-type compound and a radical polymerization initiator is only a 1st layer, it is preferable to contain it only in the 1st layer. In this case, a 1st layer becomes a conductive particle-containing layer, and a 2nd layer becomes an insulating adhesive layer. In this way, when the conductive particles are contained in the layer in which the resin flow is suppressed by radical polymerization, suppression of a rise in conduction resistance and improvement in the capture efficiency of the conductive particles can be realized.

By the way, in the anisotropic conductive film in which a 1st layer contains an acryl-type compound, a radical polymerization initiator, and conductive particle, and a 2nd layer does not contain an acryl-type compound, content of the acryl-type compound in a 1st layer is epoxy With respect to the total of the system compound, the anion polymerization curing agent, the acrylic compound, the radical polymerization initiator, and the film-forming resin, preferably 2.0 mass% or more and 16.0 mass% or less, more preferably 3.0 mass% or more and 15.0 mass% or less, more More preferably, they are 4.0 mass % or more and 14.0 mass % or less. In addition, the 2nd layer does not need to contain a radical polymerization initiator further.

As the epoxy compound, a general-purpose glycidyl ether compound, preferably a bisphenol A type epoxy resin or a bisphenol F type epoxy resin, can be used. In addition, when imparting good low-temperature fast curing properties to the anisotropic conductive film, an alicyclic epoxy compound having a higher reactivity than a general-purpose glycidyl ether-based compound can be used alone, or a general-purpose glycidyl ether-based compound It can also be used in combination with As such an alicyclic epoxy compound, what has two or more epoxy groups in a molecule|numerator is mentioned preferably. Liquid phase may be sufficient as these, and solid phase may be sufficient as them. Specific examples thereof include diglycidyl hexahydrobisphenol A, 3,4-epoxycyclohexenylmethyl-3',4'-epoxycyclohexenecarboxylate, and diepoxybicyclohexyl. Especially, since the light transmittance of hardened|cured material can be ensured and it is excellent also in quick curing, diglycidyl hexahydrobisphenol A, especially diepoxybicyclohexyl can be used preferably.

The content of the epoxy compound in the anisotropic conductive film of the present invention is preferably 2% by mass or more with respect to the total of the epoxy compound, the anion polymerization curing agent, the acrylic compound, the radical polymerization initiator, and the resin for film formation, more Preferably it is 5 mass % or more, More preferably, it is 10 mass % or more, About an upper limit, Preferably it is 35 mass % or less, More preferably, it is 30 mass % or less, More preferably, it is 25 mass % or less. When content of an epoxy-type compound is less than 2 mass %, we are anxious about physical properties, such as adhesive strength after hardening, becoming inadequate.

(Anionic polymerization curing agent)

The anisotropic conductive film of this invention contains an anion polymerization type hardening|curing agent in order to anionically polymerize an epoxy-type compound. As the anion polymerization type curing agent, a conventionally known anion polymerization type curing agent, preferably an anion polymerization type latent curing agent can be used. Specifically, an imidazole type curing agent, a hydrazide type curing agent, and boron trifluoride -Amine complex type curing agent, amine imide type curing agent, polyamine salt type curing agent, dicyandiamide type curing agent, and those made latent or modified|denatured etc. are mentioned. These can also use 2 or more types together. Moreover, if necessary, it can also be used after microencapsulation by a conventional method. An epoxy resin and a curing agent are contained in the microencapsulated curing agent (microcapsule curing agent), and in 100 parts by mass of the microcapsule type curing agent, usually 20 to 50 parts by mass of the curing agent and 80 to 50 parts by mass of the epoxy resin. is contained. As described above, in the case of the microcapsule curing agent, it is preferable to consider the amount of the curing agent in an amount excluding the epoxy resin in the microcapsule curing agent from the blending amount.

In order that content of the anion polymerization type hardening|curing agent in the anisotropic conductive film of this invention implement|achieves sufficient hardening reaction with respect to 100 mass parts of epoxy compounds, Preferably it is 30 mass parts or more, More preferably, it is 40 mass parts or more. , about the upper limit, Preferably it is 60 mass parts or less, More preferably, it is 50 mass parts or less.

(Acrylic compound)

The anisotropic conductive film of this invention contains an acryl-type compound as a radically polymerizable compound. (meth)acrylic acid, (meth)acrylate, those imide compounds, etc. are mentioned as an acrylic compound. "(meth)acrylic acid" is a term containing acrylic acid and methacrylic acid, and "(meth)acrylate" is a term containing acrylate and methacrylate. Moreover, these may be used in any state of a monomer and an oligomer, and may use a monomer and an oligomer together. As a specific example of an acrylic compound, An alkyl (meth)acrylate, for example, methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, etc.;; polyol poly(meth)acrylates such as ethylene glycol diacrylate, diethylene glycol diacrylate, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate; Aryloxy-hydroxyalkyl (meth) acrylates such as 2-hydroxy-1,3-diaryloxy propane, 2,2-bis [4- (acryloxymethoxy) phenyl] propane, 2, 2-bis[4-(acryloxypolyethoxy)phenyl]propane; In addition, dicyclopentenyl acrylate, tricyclo decanyl acrylate, tris (acryloyloxyethyl) isocyanurate, etc. are mentioned. These can be used individually or in combination of 2 or more types. Moreover, among these specific examples, the acryl-type compound which has a dicyclopentenyl group, a tricyclodecanyl group, or a triazine ring can improve the heat resistance of an anisotropic conductive film.

(Radical polymerization initiator)

The anisotropic conductive film of this invention contains the radical polymerization initiator which generate|occur|produces the free radical for radically polymerizing an acrylic compound. As a radical polymerization initiator, what generate|occur|produces a free radical by heat, such as a peroxide compound and an azo compound, can be used. Among them, from the viewpoint of the target connection temperature, connection time, pot life, etc., an organic peroxide having a half-life of 10 hours at a temperature of 40° C. or higher and a half-life of 1 minute at 180° C. or less is preferable, and a temperature of 10 hours with a half-life is preferable. An organic peroxide having a temperature of not less than 60°C and a half-life of 1 minute of not more than 170°C is more preferable.

Examples of such organic peroxides include peroxy esters, dialkyl peroxides, diacyl peroxides, peroxydicarbonates, peroxyketals, hydroperoxides, and silyl peroxides. Specific examples of the peroxyester include cumyl peroxyneodecanoate, 1,1,3,3-tetramethylbutylperoxyneodecanoate, 1-cyclohexyl-1-methylethylperoxyneodecanoate. , t-hexylperoxyneodecanoate, t-butylperoxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanonate, 2,5-dimethyl-2,5- Di(2-ethylhexanoylperoxy)hexane, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanonate, L-hexylperoxy-2-ethylhexanonate, L-butylperoxy- 2-ethylhexanonate, t-butylperoxyisobutyrate, 1,1-bis(t-butylperoxy)cyclohexane, t-hexylperoxyisopropylmonocarbonate, t-butylperoxy-3,5; 5-trimethylhexanonate, t-butylperoxylaurate, 2,5-dimethyl-2,5-di(m-toluylperoxy)hexane, t-butylperoxyisopropyl monocarbonate, t-butylper Oxy-2-ethylhexyl monocarbonate, t-hexyl peroxy benzoate, t-butyl peroxy acetate, etc. are mentioned. Specific examples of the dialkyl peroxide include α,α′-bis(t-butylperoxy)diisopropylbenzene, dicumylperoxide, 2,5-dimethyl-2,5-di(t-butylperoxy) Hexane, t-butylcumyl peroxide, etc. are mentioned. Specific examples of the hydroperoxide include diisopropylbenzene hydroperoxide and cumene hydroperoxide. Specific examples of diacyl peroxide include isobutyl peroxide, 2,4-dichlorobenzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, Succinic peroxide, benzoyl peroxytoluene, benzoyl peroxide, etc. are mentioned. Specific examples of peroxydicarbonate include di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, bis(4-t-butylcyclohexyl)peroxydicarbonate, and di-2-ethoxymethoxyperoxydicarbonate. , di(2-ethylhexylperoxy)dicarbonate, dimethoxybutylperoxydicarbonate, di(3-methyl-3-methoxybutylperoxy)dicarbonate, and the like. Specific examples of the peroxyketal 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, etc. can be heard Specific examples of the silyl peroxide include t-butyltrimethylsilylperoxide, bis(t-butyl)dimethylsilylperoxide, t-butyltrivinylsilylperoxide, bis(t-butyl)divinylsilylperoxide, tris (t-butyl)vinylsilylperoxide, t-butyltriallylsilylperoxide, bis(t-butyl)diallylsilylperoxide, tris(t-butyl)allylsilylperoxide, etc. are mentioned. These organic peroxides can use 2 or more types together.

To [ content of the radical polymerization initiator in the anisotropic conductive film of this invention / 100 mass parts of acryl-type compound ], Preferably it is 0.5 mass part or more, More preferably, it is 1 mass part or more, About an upper limit, about the effect of this invention In order to obtain, Preferably it is 5 mass parts or less, More preferably, it is 4 mass parts or less.

(Resin for film formation)

The anisotropic conductive film of this invention contains the resin for film-forming which has film-forming ability. Examples of such a film-forming resin include a phenoxy resin, an epoxy resin, an unsaturated polyester resin, a saturated polyester resin, a urethane resin, a butadiene resin, a polyimide resin, a polyamide resin, and a polyolefin resin. More than one species may be used in combination. Among these, a phenoxy resin can be used preferably from a viewpoint of film-forming property, workability, and connection reliability.

The content of the resin for film formation in the anisotropic conductive film of the present invention is preferably 25% by mass or more with respect to the total of the epoxy compound, the anion polymerization curing agent, the acrylic compound, the radical polymerization initiator, and the resin for film formation, more Preferably it is 30 mass % or more, About an upper limit, in order to acquire the effect of this invention, Preferably it is 50 mass % or less, More preferably, it is 45 mass % or less.

(conductive particles)

The anisotropic conductive film of this invention contains an electrically-conductive particle in order to enable anisotropic conductive connection. As an electrically-conductive particle, it can select suitably from what is used for the conventionally well-known anisotropic electrically-conductive film, and can use it. For example, metal particles, such as nickel, cobalt, silver, copper, gold|metal|money, palladium, alloy particles, such as solder, metal-coated resin particle|grains, etc. are mentioned. You can also use 2 or more types together. The surface of the electrically-conductive particle may be insulated to the extent which does not impair the conduction|electrical_connection after connection.

As an average particle diameter of an electrically-conductive particle, it is 1-30 micrometers generally. In order to be able to cope with the variation in the wiring height, to suppress the increase in the conduction resistance and to suppress the occurrence of a short circuit, it is preferably 2.5 µm or more, more preferably 3 µm or more, and the upper limit is preferably is 30 µm or less, more preferably 9 µm or less. The particle diameter of an electrically-conductive particle can be measured with a general particle size distribution analyzer, and can be calculated|required using the average particle size particle size distribution analyzer.

In addition, when the conductive particles are metal-coated resin particles, the particle hardness (20% K value; compressive elastic deformation characteristic K ₂₀ ) of the resin core particles is preferably 100 kgf/mm 2 or more, in order to obtain good connection reliability, more Preferably it is 200 kgf/mm<2> or more, About an upper limit, it is 1000 kgf/mm<2> or less, More preferably, it is 500 kgf/mm<2> or less. Compressive elastic deformation characteristic K20 can be measured at the measurement temperature of ₂₀ degreeC using the micro compression tester (MCT-W201, Shimadzu Corporation make), for example.

The content of the conductive particles in the anisotropic conductive film of the present invention is per square mm, preferably 50 or more, more preferably 50 or more, in order to suppress a decrease in the conductive particle trapping efficiency and suppress the occurrence of shorts. It is 200 or more, About an upper limit, Preferably it is 100000 or less, More preferably, it is 70000 or less. The measurement of this content can be performed by observing an anisotropic conductive film with an optical microscope, a metal microscope, etc. Moreover, before anisotropic conductive connection, since the electrically-conductive particle in the anisotropic conductive film exists in the said film, it may be difficult to observe with an optical microscope. In such a case, you may observe the anisotropic conductive film after anisotropic conductive connection. In this case, the abundance can be calculated in consideration of the film thickness change before and after connection.

In addition, content of the electrically-conductive particle in the anisotropic conductive film of this invention can also be expressed on a mass basis. In this case, the content is preferably 1 part by mass or more, more preferably 3 parts by mass to 100 parts by mass in total of the epoxy compound, the anion polymerization type curing agent, the acrylic compound, the radical polymerization initiator, and the resin for film formation. As mentioned above, about an upper limit, Preferably it is 30 mass parts or less, More preferably, it is an amount used as 10 mass parts or less.

In addition, as the mode of existence of the conductive particles in the anisotropic conductive film of the present invention, when the film is a single layer, it may be randomly dispersed throughout the film, or may be arranged regularly while being spaced apart from each other, When they are arranged regularly may contain a certain number of omissions or aggregation (for example, WO2016/068168A1, Japanese Patent Application Laid-Open No. 2016-066573, Japanese Patent Application Laid-Open No. 2016-085983, Japanese Patent Application Laid-Open No. 2016-092004, Japanese Unexamined Patent Publication (Kokai) 2016 -103476, see Japanese Patent 6187665). Moreover, when a film is a multilayer structure, for example, in the case of a two-layer structure, you may make it make an electrically-conductive particle exist only in one layer. Moreover, it may be made to exist in the boundary of a layer, and you may make it exist in the outer boundary surface (sticking surface) of a layer.

(Other Ingredients)

The anisotropic conductive film of this invention can contain a silane coupling agent, a filler, a softener, an accelerator, an anti-aging agent, a colorant (pigment, dye), an organic solvent, an ion catcher, etc. as needed. Moreover, you may use suitably polymerization inhibitors, such as hydroquinone and methyl ether hydroquinones, as needed. Among them, the silane coupling agent contains 0.5 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass in total of the epoxy compound, the anion polymerization type curing agent, the acrylic compound, the radical polymerization initiator, and the resin for film formation, It is preferable from a viewpoint of making the adhesiveness in between complexes favorable.

(Differential scanning calorimetric properties)

Since the anionic polymerization system and the radical polymerization system are mixed, the anisotropic conductive film of this invention has the characteristic in the exothermic peak at the time of measurement with a differential scanning calorimeter. Specifically, when the compounding composition of the anisotropic conductive film of the present invention is measured with a differential scanning calorimeter, the temperature difference is 10 ° C or more, preferably 15 ° C or more, and for a short time connection, the peak is not too far apart Because it is preferred, it is selected to have two exothermic peaks with a difference of 15 to 30°C. Thereby, the resin flow in the initial stage of anisotropic electrically conductive connection can be suppressed suitably, the trapping property of an electrically-conductive particle can be made into a favorable state, and a raise of conduction resistance can be suppressed. In addition, normally, it is thought that a lower exothermic peak originates in a radical polymerization reaction, and a higher exothermic peak originates in anionic polymerization reaction.

In this invention, the influence of the resin flow at the time of connection can be controlled by adjusting the minimum melt viscosity of a film. In general, the effect of the layer containing the conductive particles is large. In the case of two or more layers, it is calculated|required to make the minimum melt viscosity of an electrically-conductive particle containing layer larger than the layer which does not contain an electrically-conductive particle. The lowest melt viscosity can be obtained by using a rotary rheometer (manufactured by TA Instruments) as an example, maintaining a constant measuring pressure of 5 g, and using a measuring plate having a diameter of 8 mm, more specifically, the temperature range 30-200 degreeC WHEREIN: It can calculate|require by setting it as the temperature increase rate of 10 degree-C/min, the measurement frequency of 10 Hz, and 5 g of load fluctuations with respect to the said measurement plate.

(Manufacture of anisotropic conductive film)

The anisotropic conductive film of the present invention, for example, the above-mentioned epoxy compound, an anion polymerization curing agent, an acrylic compound, a radical polymerization initiator, a resin for film formation, and a composition containing conductive particles, After adjusting so that the content of the acrylic compound is less than 5% by mass based on the total of the epoxy compound and the acrylic compound, it is dissolved in an organic solvent such as toluene to make a paint, and the paint is filmed using a known film forming method It can be manufactured by In addition, when the anisotropic conductive film of this invention has a multilayer structure, after forming each layer into a film, what is necessary is just to laminate|stack those films. Further, when the conductive particles are arranged in a regular arrangement, it can be realized by employing a known method using a transfer type (Japanese Patent No. 6187665, Japanese Patent No. 6372542, Japanese Patent No. 6372543, etc.).

<connected structure>

The anisotropic conductive film of the present invention includes a first electronic component such as an IC chip, an IC module, and an FPC (sometimes referred to as COF), and a second electronic component such as a plastic substrate, a glass substrate, a rigid substrate, a ceramic substrate, and an FPC. It can be preferably applied when connecting parts by anisotropic conduction. In such an anisotropic conductive film of this invention, the bonded structure by which the 1st electronic component and the 2nd electronic component are anisotropically conductively connected is also a part of this invention. Such a bonded structure is the anisotropic conductive film of this invention, and it can manufacture by carrying out anisotropic conductive connection of a 1st electronic component and a 2nd electronic component. In addition, as a connection method of the electronic component using an anisotropic conductive film, a well-known method can be used.

Example

Hereinafter, although an Example demonstrates this invention concretely, it is not limited to the following Example.

Example 1

50 parts by mass of a microcapsule type imidazole latent curing agent (Novacure HX-3941HP, Asahi Chemical Co., Ltd.) as an anion polymerization type curing agent, 10 parts by mass of a liquid epoxy compound (jER828, Mitsubishi Chemical Co., Ltd.); As a film-forming resin, 35 parts by mass of phenoxy resin (YP-50, Nittetsu Chemicals & Materials Co., Ltd.), 10 parts by mass of an acrylic compound (epoxy ester M-600A, Kyoeisha Chemical Co., Ltd.), radical polymerization initiator (Perhexa C, Nichiyu Co., Ltd.) 2 parts by mass and a silane coupling agent (KBE-403, Shin-Etsu Chemical Co., Ltd.) 1 part by mass, conductive particles (AUL-704, Sekisui Chemical Co., Ltd.) Note)) was dispersed, and the obtained mixture was formed into a film to form a first layer (conductive particle-containing layer) having a thickness of 6 µm. The mixing amount of the conductive particles is such that the particle density in the first layer is 8000 pieces/mm 2 . Moreover, the minimum melt viscosity temperature of this 1st layer by the rotary rheometer (made by TA Instruments) was 75 degreeC.

Next, 50 parts by mass of a microcapsule type imidazole-based latent curing agent (Novacure HX3941-HP, Asahi Chemical Co., Ltd.), 15 parts by mass of a liquid epoxy compound (jER828, Mitsubishi Chemical Co., Ltd.), phenoxy resin ( A mixture consisting of 35 parts by mass of YP-50, Nittetsu Chemicals & Materials Co., Ltd.) and 1 part by mass of a silane coupling agent (KBE-403, Shin-Etsu Chemical Co., Ltd.) was formed to form a second layer with a thickness of 10 μm ( insulating adhesive layer) was formed. The lowest melt viscosity temperature of this second layer by a rotary rheometer (manufactured by TA Instruments) was 100°C.

The anisotropic conductive film of the two-layer structure of Example 1 was obtained by laminating the obtained 1st layer and 2nd layer at the roll temperature of 45 degreeC using a roll laminator.

Comparative Example 1

A first layer (conductive particle-containing layer) having a thickness of 6 µm similar to that of Example 1 was formed except that the acrylic compound and the radical polymerization initiator were not used. Similarly to Example 1, the mixing amount of an electrically-conductive particle is a quantity from which the particle density in a 1st layer will be 8000 pieces/mm<2>. In addition, the minimum melt viscosity temperature by the rotary rheometer (made by TA Instruments) of this 1st layer was 100 degreeC.

Next, a second layer (insulating adhesive layer) having the same thickness as in Example 1 (insulating adhesive layer) was formed. The minimum melt viscosity temperature of this 2nd layer by the rotary rheometer (made by TA Instruments) was also 100 degreeC similarly to Example 1.

The anisotropic conductive film of the two-layer structure of the comparative example 1 was obtained by laminating the obtained 1st layer and 2nd layer at the roll temperature of 45 degreeC using a roll laminator.

Comparative Example 2

A first layer (conductive particle-containing layer) having the same thickness as in Example 1 was formed of 6 µm. Similarly to Example 1, the mixing amount of an electrically-conductive particle is a quantity from which the particle density in a 1st layer will be 8000 pieces/mm<2>. Moreover, the minimum melt viscosity temperature of this 1st layer by the rotary rheometer (made by TA Instruments) was also 75 degreeC similarly to Example 1.

Next, 50 parts by mass of a microcapsule-type imidazole-based latent curing agent (Novacure HX3941-HP, Asahi Chemical Co., Ltd.), 10 parts by mass of a liquid epoxy compound (jER828, Mitsubishi Chemical Co., Ltd.), phenoxy resin ( YP-50, Nittetsu Chemical & Materials Co., Ltd.) 35 parts by mass, acrylic compound (epoxy ester M-600A, Kyoeisha Chemical Co., Ltd.) 10 parts by mass, radical polymerization initiator (Perhexa C, Nichiyu) Note)) 2 parts by mass and 1 part by mass of a silane coupling agent (KBE-403, Shin-Etsu Chemical Co., Ltd.) was formed into a film to form a second layer (insulating adhesive layer) having a thickness of 10 µm. The lowest melt viscosity temperature of this second layer by a rotary rheometer (manufactured by TA Instruments) was 75°C.

The anisotropic conductive film of the two-layer structure of the comparative example 2 was obtained by laminating the obtained 1st layer and 2nd layer at 45 degreeC of roll temperature using a roll laminator.

Comparative Example 3

A first layer (conductive particle-containing layer) having the same thickness as in Example 1 was formed of 6 µm. Similarly to Example 1, the mixing amount of an electrically-conductive particle is a quantity from which the particle density in a 1st layer will be 8000 pieces/mm<2>. Moreover, the minimum melt viscosity temperature of this 1st layer by the rotary rheometer (made by TA Instruments) was also 75 degreeC similarly to Example 1. In this comparative example 3, the anisotropic conductive film was comprised only with the 1st layer.

Example 2

A first layer (conductive particle-containing layer) having a thickness of 6 µm similar to that of Example 1 was formed except that the amount of the acrylic compound used was reduced from 10 parts by mass to 3 parts by mass. Similarly to Example 1, the mixing amount of an electrically-conductive particle is a quantity from which the particle density in a 1st layer will be 8000 pieces/mm<2>. Moreover, the minimum melt viscosity temperature of this 1st layer by the rotary rheometer (made by TA Instruments) was 90 degreeC.

Next, 50 parts by mass of a microcapsule type imidazole-based latent curing agent (Novacure HX3941-HP, Asahi Chemical Co., Ltd.), 15 parts by mass of a liquid epoxy compound (jER828, Mitsubishi Chemical Co., Ltd.), phenoxy resin ( A mixture consisting of 35 parts by mass of YP-50, Nittetsu Chemicals & Materials Co., Ltd.) and 1 part by mass of a silane coupling agent (KBE-403, Shin-Etsu Chemical Co., Ltd.) was formed to form a second layer with a thickness of 10 μm ( insulating adhesive layer) was formed. The lowest melt viscosity temperature of this second layer by a rotary rheometer (manufactured by TA Instruments) was 100°C.

The anisotropic conductive film of the two-layer structure of Example 2 was obtained by laminating the obtained 1st layer and 2nd layer at the roll temperature of 45 degreeC using a roll laminator.

Example 3

A first layer (conductive particle-containing layer) having a thickness of 6 µm similar to that of Example 1 was formed except that the amount of the acrylic compound used was increased from 10 parts by mass to 15 parts by mass. Similarly to Example 1, the mixing amount of an electrically-conductive particle is a quantity from which the particle density in a 1st layer will be 8000 pieces/mm<2>. Moreover, the minimum melt viscosity temperature of this 1st layer by the rotary rheometer (made by TA Instruments) was 71 degreeC.

Next, a second layer (insulating adhesive layer) having the same thickness as in Example 1 (insulating adhesive layer) was formed. The minimum melt viscosity temperature of this 2nd layer by the rotary rheometer (made by TA Instruments) was also 100 degreeC similar to Example 1.

The anisotropic conductive film of the two-layer structure of Example 3 was obtained by laminating the obtained 1st layer and 2nd layer at the roll temperature of 45 degreeC using a roll laminator.

Comparative Example 4

A first layer (conductive particle-containing layer) having a thickness of 6 μm similar to that of Example 1 was formed except that the amount of the acrylic compound used was reduced from 10 parts by mass to 1 part by mass. Similarly to Example 1, the mixing amount of an electrically-conductive particle is a quantity from which the particle density in a 1st layer will be 8000 pieces/mm<2>. Moreover, the minimum melt viscosity temperature of this 1st layer by the rotary rheometer (made by TA Instruments) was 91 degreeC.

Next, a second layer (insulating adhesive layer) having the same thickness as in Example 1 (insulating adhesive layer) was formed. The minimum melt viscosity temperature of this 2nd layer by the rotary rheometer (made by TA Instruments) was also 100 degreeC similar to Example 1.

The anisotropic conductive film of the two-layer structure of the comparative example 4 was obtained by laminating the obtained 1st layer and 2nd layer at the roll temperature of 45 degreeC using a roll laminator.

Comparative Example 5

A first layer (conductive particle-containing layer) having a thickness of 6 μm similar to that of Example 1 was formed except that the amount of the acrylic compound used was increased from 10 parts by mass to 20 parts by mass. Similarly to Example 1, the mixing amount of an electrically-conductive particle is a quantity from which the particle density in a 1st layer will be 8000 pieces/mm<2>. Moreover, the minimum melt viscosity temperature of this 1st layer by the rotary rheometer (made by TA Instruments) was 70 degreeC.

Next, a second layer (insulating adhesive layer) having the same thickness as in Example 1 (insulating adhesive layer) was formed. The minimum melt viscosity temperature of this 2nd layer by the rotary rheometer (made by TA Instruments) was also 100 degreeC similar to Example 1.

The anisotropic conductive film of the two-layer structure of the comparative example 5 was obtained by laminating the obtained 1st layer and 2nd layer at the roll temperature of 45 degreeC using a roll laminator.

<<content of acrylic compound>>

In the anisotropic conductive film and the first layer of the above Examples and Comparative Examples, the content (mass %) of the acrylic compound relative to the total of the epoxy compound, the anion polymerization curing agent, the acrylic compound, the radical polymerization initiator, and the resin for film formation calculated.

<<Preparation of connected structure>>

As an evaluation substrate, a Cu layer of a copper-clad laminated substrate (S'PERFLEX, Sumitomo Metals Mining Co., Ltd.) in which an 8 µm-thick Cu layer was formed on a 38 µm-thick polyimide film was processed into an electrode with a pitch of 50 µm, and tin A chip on flex (COF) substrate obtained by plating and a 0.7 mm thick glass substrate coated with an ITO thin film on the entire surface were anisotropically conductively connected using the anisotropic conductive films prepared in Examples and Comparative Examples. Specifically, the anisotropic conductive film prepared in Examples and Comparative Examples was slitted to a width of 1.5 mm and adhered to an ITO-coated glass substrate, a COF substrate was temporarily fixed thereon, and then a 100 μm thick perfluoropolyethylene cushioning material was interposed. Then, with a heat tool (180°C-3.5 MPa-6 sec) with a heating width of 1.5 mm, condition 1 (pressing speed 10 mm/min, stage temperature 40° C.) or condition 2 (pressing speed 1 mm/min, stage temperature 100) °C)) by thermocompression bonding, anisotropic conductive connection was performed, and a bonded structure was obtained.

＜＜Evaluation＞＞

1) Differential scanning calorimetry (DSC) measurement

About 5 mg of a sample cut out from the obtained anisotropic conductive film is stored in aluminum PAN (manufactured by TA Instruments), and it is set in a DSC measuring apparatus (Q2000, manufactured by TA Instruments), from 30°C to 250°C, 10°C DSC measurement was performed at a temperature increase rate of /min. From the obtained DSC chart, the first exothermic peak derived from the radical polymerization reaction and the second exothermic peak derived from the anionic polymerization reaction were read, and when two exothermic peaks were observed, the temperature difference between the exothermic peaks was calculated.

2) Evaluation of conduction resistance

About the bonded structure obtained by the conditions 1 or 2, the connection resistance value when 1 mA of electric current was flowed using the 4 terminal method was measured. Condition 1 is a normal connection condition, Condition 2 is a condition for evaluating whether the press-fitting property of an electrically-conductive particle falls when a radical polymerization reaction is accelerated|stimulated using conduction resistance value as an index|index. A result is shown in Table 1. Less than 1.5 Ω was evaluated as “A”, 1.5 Ω or more and less than 2 Ω as “B”, and 2.0 Ω or more as “C”. Practically, it is preferable that it is B or more in conduction resistance evaluation.

3) Evaluation of particle trapping efficiency

With respect to the bonded structure obtained under condition 1, the number of conductive particles captured per unit area of terminals existing in the anisotropic conductive connection region was counted under a microscope, and the number of conductive particles per unit area of the original conductive film of the anisotropic conductive film was counted. The ratio to the number was calculated as the particle trapping efficiency. A result is shown in Table 1. Practically, it is preferable that the particle trapping efficiency is 30% or more.

<<Consideration of evaluation results>>

(Example 1)

From the result of Table 1, in the case of Example 1, since content of the acrylic compound in the whole film was 4.8 mass %, and content of the acrylic compound in a 1st layer was 9.3 mass %, conduction in conditions 1 and 2 Resistance was A evaluation, and it became 35 % also about particle|grain capture|acquisition efficiency, and the favorable result exceeding 30 % was obtained. In the DSC measurement at that time, an exothermic peak derived from radical polymerization and an exothermic peak derived from anionic polymerization were observed, and the difference between their exothermic peaks was 25°C.

(Comparative Example 1)

On the other hand, in the case of Comparative Example 1 in which the first layer did not contain the acrylic compound and the radical polymerization initiator, the resin flow was not suppressed at the initial stage of the anisotropic conductive connection, and the conductive particles moved easily from the terminal region, resulting in particle trapping efficiency. This became 15 %, and was largely below 30 %. In the DSC measurement at that time, only an exothermic peak derived from anionic polymerization was observed.

(Comparative Example 2)

The first layer was the same as in Example 1, but in Comparative Example 2 in which the acrylic compound was also contained in the second layer, the content of the acrylic compound in the first layer was 9.3% by mass, but the acrylic compound in the entire film The content of is about 2 times (9.3 mass%) compared to the case of Example 1, the evaluation under the condition 2 of the conduction resistance is the B evaluation, and the particle trapping efficiency is 18%, significantly less than 30%, there was. In the DSC measurement at that time, an exothermic peak derived from radical polymerization and an exothermic peak derived from anionic polymerization were observed, and the difference between their exothermic peaks was 15°C.

(Comparative Example 3)

Moreover, about the 1st layer, although it was the same as Example 1, in the case of Comparative Example 3 in which the 2nd layer was not formed, as a result, the content in the whole film (meaning same as 1st layer) of the acrylic compound in Example 1 It is about 2 times compared with the case of , and evaluation by the conditions 1 and 2 of conduction resistance is B and C evaluation, Furthermore, the particle|grain capture|acquisition efficiency became 24 %, and was less than 30 %. In the DSC measurement at that time, an exothermic peak derived from radical polymerization and an exothermic peak derived from anionic polymerization were observed, and the difference between their exothermic peaks was 25°C.

(Example 2)

Since content of the acrylic compound in the whole film is 1.5 mass %, and content of the acrylic compound in a 1st layer is 3.0 mass %, conduction resistance in conditions 1 and 2 is A evaluation, and it is 33% also about particle trapping efficiency. and good results exceeding 30% were obtained. In the DSC measurement at that time, an exothermic peak derived from radical polymerization and an exothermic peak derived from anionic polymerization were observed, and the difference between their exothermic peaks was 21°C.

(Example 3)

Since the content of the acrylic compound in the entire film is 7.0% by mass and the content of the acrylic compound in the first layer is 13.4% by mass, the conduction resistance in the conditions 1 and 2 is an A evaluation, and the particle trapping efficiency is also 38% and good results exceeding 30% were obtained. In the DSC measurement at that time, an exothermic peak derived from radical polymerization and an exothermic peak derived from anionic polymerization were observed, and the difference between the exothermic peaks was 28°C.

(Comparative Example 4)

Since the content of the acrylic compound in the entire film was 0.5 mass% and the content of the acrylic compound in the first layer was 1.0 mass%, the conduction resistance in Conditions 1 and 2 were both A ratings, but the particle trapping efficiency was 26 %, and was less than 30%. In the DSC measurement at that time, an exothermic peak derived from radical polymerization and an exothermic peak derived from anionic polymerization were observed, and the difference between their exothermic peaks was 14°C.

(Comparative Example 5)

Since the content of the acrylic compound in the entire film is 9.2 mass% and the content of the acryl compound in the first layer is 17.1 mass%, the particle trapping efficiency is 43%, significantly exceeding 30%, but the conduction resistance is Evaluation under Conditions 1 and 2 was B and C evaluation. In the DSC measurement at that time, an exothermic peak derived from radical polymerization and an exothermic peak derived from anionic polymerization were observed, and the difference between their exothermic peaks was 36°C.

The present invention applies an anisotropic conductive film comprising an epoxy compound, an anion polymerization curing agent, an acrylic compound, a radical polymerization initiator, conductive particles, and a film-forming resin to mounting an electronic component on a wiring board When doing this, a raise of a connection resistance value can be suppressed, without reducing particle|grain capture|acquisition efficiency. Therefore, it is useful for anisotropic conductive connection to the wiring board of electronic components, such as an IC chip.

Claims (15)

An anisotropic conductive film comprising an epoxy compound, an anion polymerization curing agent, an acrylic compound, a radical polymerization initiator, a film-forming resin, and conductive particles,
The anisotropic conductive film whose content of an acryl-type compound is 1.0 mass % or more and 8.0 mass % or less with respect to the sum total of an epoxy-type compound, an anion polymerization type hardening|curing agent, an acryl-type compound, a radical polymerization initiator, and resin for film-forming. The anisotropic conductive film according to claim 1, wherein the first layer and the second layer each containing an epoxy compound, an anion polymerization type curing agent, and a film-forming resin are laminated, wherein at least one of the first layer and the second layer is formed. The anisotropic conductive film in which a layer contains an acryl-type compound and a radical polymerization initiator. 3. The method of claim 2,
The anisotropic conductive film in which a 1st layer contains an acryl-type compound and a radical polymerization initiator, and a 2nd layer does not contain an acryl-type compound. 4. The method of claim 3,
The anisotropic conductive film in which a 1st layer contains an electrically-conductive particle. 5. The method of claim 4,
Content of the acrylic compound in the 1st layer is 2.0 mass % or more and 16.0 mass % or less with respect to the total of an epoxy compound, an anion polymerization type hardening|curing agent, an acrylic compound, a radical polymerization initiator, and resin for film-forming, Anisotropy conductive film. 6. The method according to any one of claims 1 to 5,
An anisotropic conductive film in which the epoxy compound is a glycidyl ether compound. 7. The method of claim 6,
The anisotropic conductive film whose glycidyl ether type compound is a bisphenol A epoxy resin or a bisphenol F type epoxy resin. 8. The method according to any one of claims 1 to 7,
An anisotropic conductive film wherein the anionic polymerization curing agent is a microcapsule type imidazole latent curing agent. 9. The method according to any one of claims 1 to 8,
The anisotropic conductive film which contains 30 mass parts or more and 60 mass parts or less of an anion polymerization type hardening|curing agent with respect to 100 mass parts of epoxy-type compounds. 10. The method according to any one of claims 1 to 9,
The anisotropic conductive film which contains 0.5 mass part or more and 5 mass parts or less of a radical polymerization initiator with respect to 100 mass parts of acrylic compounds. 11. The method according to any one of claims 1 to 10,
The anisotropic conductive film which contains 25 mass % or more and 50 mass % or less of resin for film-forming with respect to the sum total of an epoxy-type compound, an anion polymerization type hardening|curing agent, an acrylic compound, a radical polymerization initiator, and resin for film-forming. 12. The method according to any one of claims 1 to 11,
The anisotropic conductive film which contains 1 mass part or more and 30 mass parts or less of conductive particles with respect to a total of 100 mass parts of an epoxy compound, an anion polymerization type hardening|curing agent, an acrylic compound, a radical polymerization initiator, and resin for film-forming. 13. The method according to any one of claims 1 to 12,
An anisotropic conductive film in which two exothermic peaks with a temperature difference of 10°C or higher exist when measured with a differential scanning calorimeter. It is an anisotropic conductive film in any one of Claims 1-12, Comprising: The bonded structure by which the 1st electronic component and the 2nd electronic component are anisotropically conductively connected. The manufacturing method of a bonded structure which carries out anisotropic conductive connection of a 1st electronic component and a 2nd electronic component with the anisotropic conductive film in any one of Claims 1-12.