JP2024025090A - Adhesive film for circuit connection, circuit connection structure, and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive film for circuit connection that is able to prevent the localization of conductive particles even under heat and pressure, while also reducing connection resistance.

SOLUTION: An adhesive film 10 for circuit connection comprises: a first adhesive layer 1 containing conductive particles 4 and a thermoplastic resin; and a second adhesive layer 2 provided on the first adhesive layer 1. The thermoplastic resin includes a resin in which at least some of hydroxy groups in a phenoxy resin are modified with a group represented by formula (1) or formula (1A).

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present disclosure relates to an adhesive film for circuit connection, a circuit connection structure, and a method for manufacturing the same.

Conventionally, conductive particles are dispersed in an adhesive film for connection between a liquid crystal display and a tape carrier package (TCP), between a flexible printed circuit board (FPC) and a TCP, or between an FPC and a printed wiring board. Anisotropically conductive films are used. Specifically, the circuit members are bonded to each other by the circuit connection part formed by the circuit connection adhesive film, and the electrodes on the circuit members are electrically connected to each other via the conductive particles in the circuit connection part. By doing so, a circuit connection structure can be obtained. Furthermore, when mounting a semiconductor silicon chip on a substrate, so-called chip on glass (COG) mounting, in which the semiconductor silicon chip is directly mounted on the substrate, is used instead of the conventional wire bonding. An anisotropically conductive film is used (see, for example, Patent Document 1).

JP2016-054288A

By the way, in anisotropic conductive films, it is difficult to control the fluidity during connection, and when a semiconductor chip and a substrate are connected (when heat and external force are applied), the adhesive component is released from the circuit connection part. Extrusion may result in localization of the conductive particles within the circuit connections. When localization of conductive particles occurs within a circuit connection portion, the conductive particles crowd together between adjacent circuits to form a short circuit, which may lead to malfunction.

Furthermore, if the anisotropically conductive film does not have sufficient fluidity, the resin expulsion between the connecting circuits may be reduced and the connection resistance may increase.

Therefore, the present disclosure provides an adhesive film for circuit connection that can suppress localization of conductive particles and reduce connection resistance even when heat and external force are applied. The main purpose is to

The present inventors investigated to solve the above problem and found that by using a specific resin as the thermoplastic resin, it is possible to suppress localization of conductive particles even when external force is applied. Furthermore, the inventors have discovered that it is possible to reduce the connection resistance, and have completed the invention of the present disclosure.

［式（１）中、Ｒ^１は水素原子又はメチル基を示し、ｘは２～６の整数を示し、ｙは１～６の整数を示す。＊はヒドロキシ基由来の酸素原子と結合する結合位置を示す。］

［式（１Ａ）中、Ｒ^１、ｘ、ｙ、及び＊は前記と同義である。＊１及び＊２は他のラジカル重合性基の炭素原子と結合する結合位置を示す。］
［２］前記第１の接着剤層の厚さが、５μｍ以下であり、前記導電粒子の平均粒径に対する前記第１の接着剤層の厚さの比が０．５０以上である、［１］に記載の回路接続用接着剤フィルム。
［３］前記第１の接着剤層が、光硬化性樹脂成分の硬化物及び第１の熱硬化性樹脂成分をさらに含有し、前記第２の接着剤層が、第２の熱硬化性樹脂成分をさらに含有する、［１］又は［２］に記載の回路接続用接着剤フィルム。
［４］前記光硬化性樹脂成分が、ラジカル重合性化合物及び光ラジカル重合開始剤を含む、［３］に記載の回路接続用接着剤フィルム。
［５］前記第１の熱硬化性樹脂成分及び前記第２の熱硬化性樹脂成分が、カチオン重合性化合物及び熱カチオン重合開始剤を含む、［３］又は［４］に記載の回路接続用接着剤フィルム。
［６］前記カチオン重合性化合物が、オキセタン化合物及び脂環式エポキシ化合物からなる群より選ばれる少なくとも１種である、［５］に記載の回路接続用接着剤フィルム。
［７］前記熱カチオン重合開始剤が、構成元素としてホウ素を含むアニオンを有する塩化合物である、［５］又は［６］に記載の回路接続用接着剤フィルム。
［８］前記第１の接着剤層の前記第２の接着剤層とは反対側に設けられた、第３の熱硬化性樹脂成分を含有する第３の接着剤層をさらに備える、［３］～［７］のいずれかに記載の回路接続用接着剤フィルム。
［９］前記第３の熱硬化性樹脂成分が、カチオン重合性化合物及び熱カチオン重合開始剤を含む、［８］に記載の回路接続用接着剤フィルム。
［１０］第１の電極を有する第１の回路部材と、第２の電極を有する第２の回路部材との間に、［１］～［９］のいずれかに記載の回路接続用接着剤フィルムを介在させ、前記第１の回路部材及び前記第２の回路部材を熱圧着して、前記第１の電極及び前記第２の電極を互いに電気的に接続する工程を備える、回路接続構造体の製造方法。
［１１］第１の電極を有する第１の回路部材と、第２の電極を有する第２の回路部材と、前記第１の回路部材及び前記第２の回路部材の間に配置され、前記第１の電極及び前記第２の電極を互いに電気的に接続する回路接続部とを備え、前記回路接続部が、［１］～［９］のに記載の回路接続用接着剤フィルムの硬化物を含む、回路接続構造体。 The present disclosure provides the circuit connection adhesive film described in [1] to [9], the method for manufacturing a circuit connection structure described in [10], and the circuit connection structure described in [11].
[1] A first adhesive layer containing conductive particles and a thermoplastic resin, and a second adhesive layer provided on the first adhesive layer, wherein the thermoplastic resin is a phenoxy resin. An adhesive film for circuit connection, comprising a resin in which at least a part of the hydroxyl groups in is modified with a group represented by the following formula (1) or the following formula (1A).

[In formula (1), R ¹ represents a hydrogen atom or a methyl group, x represents an integer of 2 to 6, and y represents an integer of 1 to 6. * indicates a bonding position that is bonded to an oxygen atom derived from a hydroxy group. ]

[In formula (1A), R ¹ , x, y, and * have the same meanings as above. *1 and *2 indicate bonding positions with carbon atoms of other radically polymerizable groups. ]
[2] The thickness of the first adhesive layer is 5 μm or less, and the ratio of the thickness of the first adhesive layer to the average particle diameter of the conductive particles is 0.50 or more, [1 The adhesive film for circuit connection described in ].
[3] The first adhesive layer further contains a cured product of a photocurable resin component and a first thermosetting resin component, and the second adhesive layer further contains a cured product of a photocurable resin component and a first thermosetting resin component. The adhesive film for circuit connection according to [1] or [2], further containing a component.
[4] The adhesive film for circuit connection according to [3], wherein the photocurable resin component contains a radically polymerizable compound and a radical photopolymerization initiator.
[5] The circuit connection according to [3] or [4], wherein the first thermosetting resin component and the second thermosetting resin component contain a cationic polymerizable compound and a thermal cationic polymerization initiator. adhesive film.
[6] The adhesive film for circuit connection according to [5], wherein the cationically polymerizable compound is at least one selected from the group consisting of oxetane compounds and alicyclic epoxy compounds.
[7] The adhesive film for circuit connection according to [5] or [6], wherein the thermal cationic polymerization initiator is a salt compound having an anion containing boron as a constituent element.
[8] Further comprising a third adhesive layer containing a third thermosetting resin component, which is provided on the opposite side of the first adhesive layer from the second adhesive layer. ] to [7]. The adhesive film for circuit connection according to any one of [7].
[9] The adhesive film for circuit connection according to [8], wherein the third thermosetting resin component contains a cationic polymerizable compound and a thermal cationic polymerization initiator.
[10] The circuit connecting adhesive according to any one of [1] to [9] is applied between the first circuit member having the first electrode and the second circuit member having the second electrode. A circuit connection structure comprising the step of electrically connecting the first electrode and the second electrode to each other by interposing a film and thermocompression bonding the first circuit member and the second circuit member. manufacturing method.
[11] A first circuit member having a first electrode, a second circuit member having a second electrode, disposed between the first circuit member and the second circuit member, a circuit connecting part that electrically connects the first electrode and the second electrode to each other, the circuit connecting part is made of a cured product of the adhesive film for circuit connection according to [1] to [9]. Including, circuit connection structure.

According to the present disclosure, an adhesive film circuit connection for circuit connection is capable of suppressing localization of conductive particles and reducing connection resistance even when heat and external force are applied. An adhesive film is disclosed. Further, according to the present disclosure, a circuit connection structure using such a circuit connection adhesive film and a method for manufacturing the same are disclosed.

FIG. 1 is a schematic cross-sectional view showing one embodiment of an adhesive film for circuit connection. FIG. 2 is a schematic cross-sectional view showing one embodiment of the circuit connection structure. FIG. 3 is a schematic cross-sectional view showing one embodiment of a method for manufacturing a circuit connection structure. FIGS. 3(a) and 3(b) are schematic cross-sectional views showing each step.

Embodiments of the present disclosure will be described in detail below. However, the present disclosure is not limited to the following embodiments.

In this specification, a numerical range indicated using "~" indicates a range that includes the numerical values written before and after "~" as the minimum and maximum values, respectively. In the numerical ranges described stepwise in this specification, the upper limit or lower limit of the numerical range of one step may be replaced with the upper limit or lower limit of the numerical range of another step. Further, in the numerical ranges described in this specification, the upper limit or lower limit of the numerical range may be replaced with the value shown in the Examples. Moreover, the upper limit values and lower limit values described individually can be combined arbitrarily. In the notation of numerical range "A to B", numerical values A and B at both ends are included in the numerical range as the lower limit value and upper limit value, respectively. In this specification, for example, the description "10 or more" means "10" and "a numerical value exceeding 10", and this also applies when the numerical values are different. Further, for example, the description "10 or less" means "10" and "a numerical value less than 10", and this applies even if the numerical values are different.

As used herein, "(meth)acrylate" means at least one of acrylate and methacrylate corresponding thereto. The same applies to other similar expressions such as "(meth)acryloyl" and "(meth)acrylic acid." Further, "A or B" may include either A or B, or both.

The materials exemplified below may be used alone or in combination of two or more, unless otherwise specified. When a plurality of substances corresponding to each component are present in the composition, the content of each component in the composition means the total amount of the plurality of substances present in the composition, unless otherwise specified.

[Adhesive film for circuit connection]
FIG. 1 is a schematic cross-sectional view showing one embodiment of an adhesive film for circuit connection. The circuit connection adhesive film 10 (hereinafter sometimes simply referred to as "adhesive film 10") shown in FIG. 1 contains conductive particles 4 and an adhesive component 5 containing a predetermined resin as a thermoplastic resin. A first adhesive layer 1 containing the adhesive layer 1 and a second adhesive layer 2 provided on the first adhesive layer 1 are provided. The adhesive film 10 has a first region formed from the first adhesive film (first adhesive layer 1) and a second region provided adjacent to the first region. There may be a second region formed from an adhesive film (second adhesive layer 2). That is, the adhesive film 10 includes a first region containing the adhesive component 5 containing a predetermined resin as a thermoplastic resin, and a second region provided adjacent to the first region. You can also say that.

In the adhesive film 10, conductive particles 4 are dispersed in the first adhesive layer 1. Therefore, the adhesive film 10 may be an adhesive film for circuit connection (anisotropic conductive adhesive film) having anisotropic conductivity. The adhesive film 10 is interposed between a first circuit member having a first electrode and a second circuit member having a second electrode, and heats the first circuit member and the second circuit member. It may be used to electrically connect the first electrode and the second electrode to each other by crimping.

<First adhesive layer>
The first adhesive layer 1 contains conductive particles 4 (hereinafter sometimes referred to as "component (A)") and a thermoplastic resin (hereinafter sometimes referred to as "component (B)"). The first adhesive layer 1 consists of a cured product of a photocurable resin component (hereinafter sometimes referred to as "component (C)") and a thermosetting resin component (hereinafter sometimes referred to as "component (D)"). ) may further be contained. The first adhesive layer 1 irradiates a composition layer made of a composition containing, for example, component (A), component (B), component (C), and component (D) with light energy, It can be obtained by polymerizing components contained in component (C) and curing component (C). The first adhesive layer 1 may contain an adhesive component 5 including component (A), a cured product of component (B), component (C), and component (D). The cured product of component (C) may be a cured product obtained by completely curing component (C), or may be a cured product obtained by partially curing component (C). Component (D) is a component that can flow upon circuit connection, and may be, for example, an uncured curable resin component.

(A) Component: Conductive particles (A) Component is not particularly limited as long as it has conductivity, and includes metal particles made of metal such as Au, Ag, Pd, Ni, Cu, and solder, and conductive carbon. The conductive carbon particles may be made of conductive carbon particles or the like. Component (A) may be coated conductive particles comprising a core containing non-conductive glass, ceramic, plastic (polystyrene, etc.), and a coating layer containing the above-mentioned metal or conductive carbon and covering the core. good. Among these, component (A) is preferably a coating comprising a core containing metal particles or plastic made of a heat-fusible metal, and a coating layer containing metal or conductive carbon and covering the core. They are conductive particles. Such coated conductive particles can easily deform the cured product of the thermosetting resin component by heating or pressurizing, so they are used, for example, when electrically connecting opposing electrodes of a semiconductor chip and a substrate , the contact area between the electrode and the component (A) can be increased, and the conductivity between the electrodes can be further improved.

Component (A) may be insulating coated conductive particles comprising the metal particles, conductive carbon particles, or coated conductive particles described above, and an insulating layer that includes an insulating material such as a resin and covers the surface of the particles. good. When component (A) is an insulating coated conductive particle, even if the content of component (A) is large, the surface of the particle is provided with an insulating layer, so short circuits due to contact between components (A) occur. It is possible to suppress the occurrence of such damage, and it is also possible to improve the insulation between adjacent electrode circuits in the semiconductor chip and substrate.

The maximum particle size of component (A) needs to be smaller than the minimum interval between electrodes (the shortest distance between adjacent electrodes). The maximum particle size of component (A) may be 1 μm or more, 2 μm or more, or 2.5 μm or more from the viewpoint of excellent dispersibility and conductivity. The maximum particle size of component (A) may be 20 μm or less, 10 μm or less, or 5 μm or less from the viewpoint of excellent dispersibility and conductivity. In this specification, the particle size of 300 arbitrary conductive particles (pcs) is measured by observation using a scanning electron microscope (SEM), and the largest value obtained is defined as the maximum particle size of component (A). shall be. In addition, when the (A) component is not spherical, such as when the (A) component has a protrusion, the particle size of the (A) component is the diameter of the circle circumscribing the conductive particle in the SEM image.

The average particle size of component (A) may be 1 μm or more, 2 μm or more, or 2.5 μm or more from the viewpoint of excellent dispersibility and conductivity. The average particle diameter of component (A) may be 20 μm or less, 10 μm or less, or 5 μm or less from the viewpoint of excellent dispersibility and conductivity. In this specification, the particle size of 300 arbitrary conductive particles (pcs) is measured by observation using a scanning electron microscope (SEM), and the simple average value of the obtained particle sizes is defined as the average particle size. .

In the first adhesive layer 1, the component (A) is preferably uniformly dispersed. From the viewpoint of obtaining stable connection resistance, the particle density of component (A) in the adhesive film 10 is 100 particles/ ^mm2 or more, 1000 particles/ ^mm2 or more, 3000 particles/ ^mm2 or more, or 5000 particles/mm2 or more. It may be ² or more. From the viewpoint of improving the insulation between adjacent electrodes, the particle density of component (A) in the adhesive film 10 is 100,000 particles/mm ² or less, 70,000 particles/mm ² or less, 50,000 particles/mm ² or less, or 30,000 particles/mm 2 or less. pieces/mm ² or less.

The content of component (A) is 1% by mass or more, 5% by mass or more, or 10% by mass or more based on the total mass of the first adhesive layer, from the viewpoint of further improving the conductivity. It's good to be there. The content of component (A) may be 80% by mass or less, 60% by mass or less, or 40% by mass or less based on the total mass of the first adhesive layer, from the viewpoint of easily suppressing short circuits. When the content of component (A) is within the above range, the effects of the present disclosure tend to be significantly exhibited. Note that the content of component (A) in the composition or composition layer (based on the total mass of the composition or composition layer) may be the same as the above range.

(B) Component: Thermoplastic resin (B) component is a resin (hereinafter referred to as , may be referred to as "component (B1)"). The component (B1) is not included in the component (C1) (radically polymerizable compound) described below. In addition to component (B1), component (B) may further contain a thermoplastic resin other than component (B1) (hereinafter sometimes referred to as "component (B2)").

・Component (B1): A resin in which at least a portion of the hydroxyl groups in the phenoxy resin are modified with a group represented by formula (1) or formula (1A) At least a portion of the hydroxyl groups in the phenoxy resin are modified with a group represented by the formula (1) The resin modified with the group represented by 1) (hereinafter sometimes referred to as "resin (1)") is a reaction product of a phenoxy resin and an isocyanate compound having a (meth)acryloyl group. be able to. Here, the isocyanate compound having a (meth)acryloyl group is a compound represented by the following formula (2). That is, the group represented by formula (1) is a group derived from the compound represented by formula (2). Resin (1) is a component that can act as a thermoplastic resin.

An adhesive for circuit connection that can suppress localization of conductive particles even when heat and external force are applied because the adhesive composition contains component (B1) as component (B). It becomes possible to form a film. Although the reason for such an effect is not necessarily clear, the present inventors have discovered that (method) in the group represented by formula (1) can be removed between or within molecules by light irradiation (e.g. ultraviolet light) or heat. ) It is speculated that this is because the acryloyl groups are crosslinked and the toughness of the film is improved, which effectively prevents the conductive particles from coming close to each other. Further, such effects tend to be further improved when the component (B) contains the components (B1) and (B2).

In formula (1), R ¹ represents a hydrogen atom or a methyl group. x represents an integer of 2 to 6, and may be 2 to 5, 2 to 4, or 2 to 3. y represents an integer of 1 to 6, and may be 1 to 5, 1 to 4, 1 to 3, or 1 to 2. * indicates a bonding position that is bonded to an oxygen atom derived from a hydroxy group.

In formula (2), R ¹ , x, and y have the same meanings as above.

The compound represented by formula (2) can be obtained by a known method such as the phosgene method using a corresponding amino alcohol having an ether bond, or a commercially available product can also be used. The compound represented by formula (2) is, for example, an amino alcohol having an ether bond such as 2-(2-aminoethoxy)ethanol, 2-(2-(2-aminoethoxy)ethoxy)ethanol, and (meth) It can be obtained by reacting with an acid chloride such as acrylic acid chloride and further reacting with phosgene. Commercially available products include Karenz (registered trademark) MOI (a compound represented by formula (2) in which R ¹ is a methyl group, x is 2, and y is 1, manufactured by Showa Denko K.K.), Karenz (registered trademark) AOI (a compound represented by formula (2) in which R ¹ is a hydrogen atom, x is 2, and y is 1, manufactured by Showa Denko K.K.), Karenz (registered trademark) MOI-EG (R ¹ is a methyl group, x is 2, a compound represented by formula (2) where y is 2 (manufactured by Showa Denko K.K.), and the like.

A phenoxy resin can be obtained, for example, by reacting a polyhydric phenol compound and a polyhydric epoxy compound. Such phenoxy resins usually have a structure in which an aliphatic hydroxyl group is generated at the bonding site where an aromatic hydroxyl group (hydroxyl group) and an epoxy group have reacted (for example, a structure derived from the following formula (X)). ing. As such phenoxy resins, those obtained by reacting bisphenols with diglycidyl etherified bisphenols are easily available and common.

Examples of polyhydric phenol compounds include bisphenol A, bisphenol F, and the like. Examples of the polyvalent epoxy compound include bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, and the like.

Phenoxy resin can be a polyhydroxy polyether (thermoplastic resin) synthesized from bisphenols and epichlorohydrin. Such phenoxy resins usually have a structure derived from the following formula (X) derived from epichlorohydrin (* indicates a bonding position), and the hydroxyl group of the phenoxy resin is a methine carbon atom ( ^CA ).

A commercially available phenoxy resin can be used. Commercially available phenoxy resins include, for example, FX-293, YP-70, ZX1356-2, FX-310, TOPR-300 (all manufactured by Nippon Steel Chemical & Materials Co., Ltd.), PKHA, PKHB, PKHC, PKHH, Examples include PKHJ, PKFE, PKHP-200 (all manufactured by Huntsman International LLC.), jER1256, jER4250, jER4275 (all manufactured by Mitsubishi Chemical Corporation), H360, EXA-192 (all manufactured by DIC Corporation).

The modification ratio of the group represented by formula (1) to the hydroxyl group of the phenoxy resin may be 0.5 to 50%. When the modification rate is 0.5% or more, localization of conductive particles tends to be sufficiently suppressed. When the modification rate is 50% or less, the connection resistance of the circuit connection portion tends to be better. The modification rate may be 1.0% or more, 3.0% or more, or 5.0% or more, and may be 40% or less, 30% or less, 20% or less, 15% or less, or 10% or less. There may be.

Here, the modification rate of the group represented by formula (1) with respect to the hydroxyl group of the phenoxy resin can be determined by measuring ¹ H-NMR of the resin modified with the group represented by formula (1), and It can be calculated from the integral value of the peak in the spectrum. In addition to the structure derived from the above formula (X), the resin modified with the group represented by formula (1) has a structure derived from the following formula (Y) (* indicates the bonding position). are doing. In the structure derived from formula (X), the chemical shift value (based on the methyl group of tetramethylsilane (TMS)) assigned to the hydrogen atom ( ^HA ) bonded to the methine carbon atom (C ^A ) is usually , observed at δ4.2 to 4.4. On the other hand, in the structure derived from formula (Y), the chemical shift value (based on the methyl group of tetramethylsilane (TMS)) assigned to the hydrogen atom (H ^B ) bonded to the methine carbon atom (C ^B ) is , H ^A is shifted down the magnetic field from the chemical shift value assigned to A, and is usually observed at δ5.2 to 6.0. Therefore, the ratio of the integral value of the peak attributed to the hydrogen atom (H ^B ) to the sum of the integral value of the peak attributed to the hydrogen atom (H ^A ) and the integral value of the peak attributed to the hydrogen atom (H ^B ) is The denaturation rate can be determined by determining (percentage) (integral value of ^HB /(integral value of ^HA +integral value of ^HB )×100(%)). In addition, by plotting the relationship between the amount of the compound represented by formula (2) added and the modification rate when reacting the phenoxy resin and the compound represented by formula (2), and creating a calibration curve, The modification rate can be derived from the amount of the compound represented by formula (2) added.

Resin (1) can be obtained by reacting a phenoxy resin and a compound represented by formula (2) in an organic solvent, optionally in the presence of a catalyst.

The amount of the compound represented by formula (2) to be added can be arbitrarily set so that the modification rate of the group represented by formula (1) to the hydroxyl group of the phenoxy resin becomes a predetermined value. The amount of the compound represented by formula (2) added may be 0.5 to 50 mol% based on the molar amount of all hydroxy groups in the phenoxy resin. The amount of the compound represented by formula (2) added is 1.0 mol% or more, 3.0 mol% or more, or 5.0 mol% or more based on the molar amount of the total hydroxyl groups of the phenoxy resin. It may be 40 mol% or less, 30 mol% or less, 20 mol% or less, 15 mol% or less, or 10 mol% or less.

The organic solvent can be used without particular limitation as long as it can dissolve the phenoxy resin and the compound represented by formula (2). Examples of organic solvents include aromatic hydrocarbons such as toluene, xylene, mesitylene, cumene, and p-cymene; aliphatic hydrocarbons such as hexane and heptane; cyclic alkanes such as methylcyclohexane; tetrahydrofuran, 1,4-dioxane, etc. cyclic ethers; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, 4-hydroxy-4-methyl-2-pentanone; esters such as methyl acetate, ethyl acetate, butyl acetate, methyl lactate, ethyl lactate, γ-butyrolactone, etc. carbonic acid esters such as ethylene carbonate and propylene carbonate; amides such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone (NMP).

As the catalyst, a urethanization catalyst can be used. Examples of the catalyst include tin-based catalysts such as dibutyltin dilaurate, dibutyltin dichloride, dibutyltin oxide, dibutyltin dibromide, dibutyltin dimaleate, and dioctyltin dilaurate; triethylamine, triethylenediamine (TEDA), 1,8-diazabicyclo[ Amine catalysts such as 5.4.0] undecene-7 (DBU), 1,5-diazabicyclo[4.3.0]nonene-5 (DBN), and 1-isobutyl-2-methylimidazole (IBM); normal Examples include zirconium-based catalysts such as propyl zirconate, normal butyl zirconate, zirconium tetraacetylacetonate, zirconium monoacetylacetonate, and zirconium ethylacetoacetate. The content of the catalyst may be 0.01 to 1% by mass based on the total mass of the compound represented by formula (2).

The reaction temperature of the phenoxy resin and the compound represented by formula (2) may be, for example, 0 to 200°C, 20 to 150°C, or 40 to 100°C. The time for maintaining the above reaction temperature may be, for example, 0.1 to 12 hours, and may be 8 hours or less, 6 hours or less, or 4 hours or less.

In the first adhesive layer 1, the (meth)acryloyl group of the group represented by the formula (1) in the resin (1) is different from the group represented by the other formula (1) in the resin (1). By reacting with the (meth)acryloyl group or the radically polymerizable group of the component (C1) described below (radical polymerization proceeds), the (meth)acryloyl group of the group represented by formula (1) in resin (1) The carbon atom of the group and other radically polymerizable groups ((meth)acryloyl group of other groups represented by formula (1) in resin (1), radically polymerizable group of component (C1) described below, etc.) may form a bond with a carbon atom. That is, some or all of the groups represented by formula (1) in resin (1) may be converted to groups represented by formula (1A).

In formula (1A), R ¹ , x, y, and * have the same meanings as above. *1 and *2 indicate bonding positions with carbon atoms of other radically polymerizable groups.

The content of component (B1) is 20 to 100% by mass, 30 to 100% by mass, 40 to 100% by mass, 50 to 100% by mass, 60 to 100% by mass, based on the total mass of component (B). It may be 70-100% by weight, or 80-100% by weight.

・(B2) component: Thermoplastic resin other than the (B1) component Examples of the (B2) component include phenoxy resins, polyester resins, and polyamides that are not modified with groups represented by formula (1) or formula (1A). Examples include resin, polyurethane resin, polyester urethane resin, acrylic rubber, and the like. Among these, component (B2) may be, for example, a phenoxy resin that is not modified with a group represented by formula (1) or formula (1A).

The content of component (B2) is, for example, 0 to 80 mass%, 0 to 70 mass%, 0 to 60 mass%, 0 to 50 mass%, 0 to 40 mass%, based on the total mass of component (B). %, 0-30% by weight, or 0-20% by weight.

The content of component (B) may be 1% by mass or more, 5% by mass or more, or 10% by mass or more, and 50% by mass or less, 40% by mass or less, based on the total mass of the adhesive composition. Or it may be 30% by mass or less. Note that the content of component (B) in the adhesive layer (based on the total mass of the adhesive layer) may be the same as the above range.

(C) Component: Photocurable resin component The first adhesive layer 1 may further contain a cured product of the (C) component. By curing the component (C), it is possible to suppress the fluidity of the conductive particles at the time of circuit connection and to suppress the deterioration in the expulsion of the resin. Component (C) is not particularly limited as long as it is a resin component that is cured by light irradiation, but if component (D) is a resin component that has cationic curability, it has radical curability from the viewpoint of better connection resistance. It may be a resin component. Component (C) includes, for example, a radically polymerizable compound (hereinafter sometimes referred to as "(C1) component") and a photoradical polymerization initiator (hereinafter sometimes referred to as "(C2) component"). It's okay to stay. Component (C) may be a component consisting of component (C1) and component (C2).

- Component (C1): Radically polymerizable compound Component (C1) is a compound that undergoes polymerization or crosslinking by radicals generated by irradiating component (C2) with light (for example, ultraviolet light). Component (C1) may be a monomer or a polymer (or oligomer) formed by polymerizing one or more monomers.

Component (C1) is a compound having a radically polymerizable group that reacts with radicals. Examples of the radically polymerizable group include (meth)acryloyl group, vinyl group, allyl group, styryl group, alkenyl group, alkenylene group, and maleimide group. The number of radically polymerizable groups (number of functional groups) that the component (C1) has is 2 or more, from the viewpoints that the desired melt viscosity is easily obtained after polymerization, the connection resistance reduction effect is further improved, and the connection reliability is more excellent. From the viewpoint of suppressing curing shrinkage during polymerization, it may be 10 or less. In addition, in order to balance crosslinking density and curing shrinkage, in addition to compounds with the number of radically polymerizable groups within the above range, compounds with the number of radically polymerizable groups outside the above range may also be used. good.

The component (C1) may contain, for example, a polyfunctional (bifunctional or more) (meth)acrylate from the viewpoint of suppressing the flow of the conductive particles. The polyfunctional (bifunctional or more) (meth)acrylate may be a bifunctional (meth)acrylate, and the bifunctional (meth)acrylate may be a bifunctional aromatic (meth)acrylate.

Examples of polyfunctional (meth)acrylates include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, and polyethylene glycol di(meth)acrylate. ) acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, tetrapropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, ethoxylated polypropylene glycol Di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate (meth)acrylate, 1,6-hexanediol di(meth)acrylate, 2-butyl-2-ethyl-1,3-propanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1 Aliphatic ( meth)acrylate; ethoxylated bisphenol A type di(meth)acrylate, propoxylated bisphenol A type di(meth)acrylate, ethoxylated propoxylated bisphenol A type di(meth)acrylate, ethoxylated bisphenol F type di(meth)acrylate, Propoxylated bisphenol F type di(meth)acrylate, ethoxylated propoxylated bisphenol F type di(meth)acrylate, ethoxylated fluorene type di(meth)acrylate, propoxylated fluorene type di(meth)acrylate, ethoxylated propoxylated fluorene type Aromatic (meth)acrylates such as di(meth)acrylate, trimethylolpropane tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, ethoxylated propoxylated tri(meth)acrylate Methylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, ethoxylated pentaerythritol tri(meth)acrylate, propoxylated pentaerythritol tri(meth)acrylate, ethoxylated propoxylated pentaerythritol tri(meth)acrylate, pentaerythritol Tetra(meth)acrylate, Ethoxylated Pentaerythritol Tetra(meth)acrylate, Propoxylated Pentaerythritol Tetra(meth)acrylate, Ethoxylated Propoxylated Pentaerythritol Tetra(meth)acrylate, Ditrimethylolpropane Tetraacrylate, Dipentaerythritol Hexa(meth)acrylate ) aliphatic (meth)acrylates such as acrylate; aromatic epoxy (meth)acrylates such as bisphenol-type epoxy (meth)acrylate, phenol novolac-type epoxy (meth)acrylate, and cresol novolac-type epoxy (meth)acrylate;

The content of polyfunctional (bifunctional or more) (meth)acrylate is, for example, 40 to 100% based on the total mass of the component (C1), from the viewpoint of achieving both the effect of reducing connection resistance and the suppression of particle flow. % by weight, 50-100% by weight, or 60-100% by weight.

Component (C1) may further contain a monofunctional (meth)acrylate in addition to a polyfunctional (bifunctional or more) (meth)acrylate. Examples of monofunctional (meth)acrylates include (meth)acrylic acid; methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, Butoxyethyl (meth)acrylate, isoamyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, heptyl (meth)acrylate, octylheptyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate Acrylate 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, ethoxy Aliphatic (meth)acrylates such as polyethylene glycol (meth)acrylate, methoxypolypropylene glycol (meth)acrylate, ethoxypolypropylene glycol (meth)acrylate, mono(2-(meth)acryloyloxyethyl)succinate; benzyl (meth)acrylate , phenyl (meth)acrylate, o-biphenyl (meth)acrylate, 1-naphthyl (meth)acrylate, 2-naphthyl (meth)acrylate, phenoxyethyl (meth)acrylate, p-cumylphenoxyethyl (meth)acrylate, o - Phenylphenoxyethyl (meth)acrylate, 1-naphthoxyethyl (meth)acrylate, 2-naphthoxyethyl (meth)acrylate, phenoxypolyethylene glycol (meth)acrylate, nonylphenoxypolyethylene glycol (meth)acrylate, phenoxypolypropylene glycol (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 2-hydroxy-3-(o-phenylphenoxy)propyl (meth)acrylate, 2-hydroxy-3-(1-naphthoxy)propyl (meth)acrylate, 2- Aromatic (meth)acrylates such as hydroxy-3-(2-naphthoxy)propyl (meth)acrylate; (meth)acrylates having epoxy groups such as glycidyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate Examples include (meth)acrylates having an alicyclic epoxy group, such as, and (meth)acrylates having an oxetanyl group, such as (3-ethyloxetan-3-yl)methyl(meth)acrylate.

The content of monofunctional (meth)acrylate may be, for example, 0 to 60% by mass, 0 to 50% by mass, or 0 to 40% by mass, based on the total mass of component (C1).

The cured product of component (C) may have, for example, a polymerizable group that reacts with reactions other than radicals. The polymerizable group that reacts with other than radicals may be, for example, a cationically polymerizable group that reacts with cations. Examples of the cationically polymerizable group include epoxy groups such as glycidyl groups, alicyclic epoxy groups such as epoxycyclohexylmethyl groups, and oxetanyl groups such as ethyloxetanylmethyl groups. Polymerizable groups that react with non-radicals include, for example, (meth)acrylates that have an epoxy group, (meth)acrylates that have an alicyclic epoxy group, (meth)acrylates that have an oxetanyl group, etc. By using a (meth)acrylate having a group as the component (C1), it can be introduced into the cured product of the component (C). (C1) Mass ratio of (meth)acrylate having a polymerizable group that reacts with something other than radicals to the total mass of the component (mass of (meth)acrylate having a polymerizable group that reacts with something other than radicals (amount charged)/(C1) The total mass (charged amount) of the components may be, for example, 0 to 0.7, 0 to 0.5, or 0 to 0.3 from the viewpoint of improving reliability.

Component (C1) may contain other radically polymerizable compounds in addition to polyfunctional (bifunctional or more) and monofunctional (meth)acrylates. Examples of other radically polymerizable compounds include maleimide compounds, vinyl ether compounds, allyl compounds, styrene derivatives, acrylamide derivatives, and nadimide derivatives. The content of other radically polymerizable compounds may be, for example, 0 to 40% by mass based on the total mass of component (C1).

・Component (C2): Radical photopolymerization initiator Component (C2) is a light containing a wavelength within the range of 150 to 750 nm, a light containing a wavelength within the range of 254 to 405 nm, or a light containing a wavelength of 365 nm (e.g. It is a photopolymerization initiator that generates radicals upon irradiation with ultraviolet light.

Component (C2) is decomposed by light to generate free radicals. In other words, component (C2) is a compound that generates radicals when external light energy is applied. (C2) component is an oxime ester structure, bisimidazole structure, acridine structure, α-aminoalkylphenone structure, aminobenzophenone structure, N-phenylglycine structure, acylphosphine oxide structure, benzyl dimethyl ketal structure, α-hydroxyalkylphenone structure It may be a compound having a structure such as. Component (C2) is selected from the group consisting of an oxime ester structure, an α-aminoalkylphenone structure, and an acylphosphine oxide structure, from the viewpoint of easily obtaining the desired melt viscosity and from the viewpoint of being more effective in reducing connection resistance. It may be a compound having at least one type of structure.

Specific examples of compounds having an oxime ester structure include 1-phenyl-1,2-butanedione-2-(o-methoxycarbonyl)oxime, 1-phenyl-1,2-propanedione-2-(o-methoxycarbonyl) ) oxime, 1-phenyl-1,2-propanedione-2-(o-ethoxycarbonyl)oxime, 1-phenyl-1,2-propanedione-2-o-benzoyloxime, 1,3-diphenylpropanetrione- 2-(o-ethoxycarbonyl)oxime, 1-phenyl-3-ethoxypropanetrione-2-(o-benzoyl)oxime, 1,2-octanedione, 1-[4-(phenylthio)phenyl-,2-( o-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-,1-(o-acetyloxime), and the like.

Specific examples of compounds having an α-aminoalkylphenone structure include 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1 -morpholinophenyl)-butanone-1 and the like.

Specific examples of compounds having an acylphosphine oxide structure include bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide, bis(2,4,6,-trimethylbenzoyl)-phenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and the like.

From the viewpoint of suppressing the flow of conductive particles, the content of component (C2) is, for example, 0.1 to 10 parts by mass, 0.3 to 7 parts by mass, or 0 to 100 parts by mass of component (C1). It may be from .5 to 5 parts by weight.

The content of the cured product of component (C) (total of components (C1) and (C2)) is determined by 1 mass based on the total mass of the first adhesive layer, from the viewpoint of suppressing the flow of conductive particles. % or more, 5% by mass or more, or 10% by mass or more. The content of the cured product of component (C) is 50% by mass or less, 40% by mass or less, or 30% by mass or less based on the total mass of the first adhesive layer, from the viewpoint of reducing connection resistance. It's good. When the content of the cured product of component (C) is within the above range, the effects of the present disclosure tend to be significantly exhibited. Note that the content of component (C) in the composition or composition layer (based on the total mass of the composition or composition layer) may be the same as the above range.

(D) Component: Thermosetting resin component The first adhesive layer 1 may further contain (D) component. Component (D) is not particularly limited as long as it is a resin component that hardens with heat, but when component (C) is a resin component that has radical curability, component (D) is selected from the viewpoint of superior connection resistance. , may be a resin component having cationic curability. Component (D) includes, for example, a cationic polymerizable compound (hereinafter sometimes referred to as "component (D1)") and a thermal cationic polymerization initiator (hereinafter sometimes referred to as "component (D2)"). It's okay to stay. Component (D) may be a component consisting of component (D1) and component (D2). Note that the first thermosetting resin component, the second thermosetting resin component, and the third thermosetting resin component are the first adhesive layer, the second adhesive layer, and the third thermosetting resin component, respectively. It refers to the thermosetting resin component contained in the adhesive layer, and refers to the components contained in the first thermosetting resin component, the second thermosetting resin component, and the third thermosetting resin component (for example, The types and contents of (D1) component, (D2) component, etc.) may be the same or different.

- Component (D1): Cationically polymerizable compound Component (D1) is a compound that polymerizes or crosslinks component (D2) by a substance (acid, etc.) generated by heating. Note that component (D1) means a compound that does not have a radically polymerizable group that reacts with radicals, and component (D1) is not included in component (C1). Component (D1) may be, for example, at least one selected from the group consisting of oxetane compounds and alicyclic epoxy compounds, from the viewpoint of further improving the effect of reducing connection resistance and providing superior connection reliability. Component (D1) preferably contains both an oxetane compound and an alicyclic epoxy compound from the viewpoint of easily obtaining a desired melt viscosity.

The oxetane compound as component (D1) can be used without any particular restriction as long as it has an oxetanyl group and does not have a radically polymerizable group. Commercially available oxetane compounds include, for example, ETERNACOLL OXBP (trade name, 4,4'-bis[(3-ethyl-3-oxetanyl)methoxymethyl]biphenyl, manufactured by Ube Industries, Ltd.), OXSQ, OXT-121, Examples include OXT-221, OXT-101, OXT-212 (trade name, manufactured by Toagosei Co., Ltd.).

The alicyclic epoxy compound as component (D1) can be used without particular limitation as long as it has an alicyclic epoxy group (for example, an epoxycyclohexyl group) and does not have a radically polymerizable group. Examples of commercially available alicyclic epoxy compounds include EHPE3150, EHPE3150CE, Celloxide 8010, Celloxide 2021P, Celloxide 2081 (trade name, manufactured by Daicel Corporation), and the like.

- Component (D2): Thermal cationic polymerization initiator Component (D2) is a thermal polymerization initiator that generates acid and the like upon heating to initiate polymerization. Component (D2) may be a salt compound composed of a cation and an anion. Component (D2) is, for example, BF ₄ ^- , BR ₄ ^- (R represents a phenyl group substituted with two or more fluorine atoms or two or more trifluoromethyl groups), PF ₆ ^- , SbF ₆ ^- , AsF ₆ ^-, and other anion-containing onium salts such as sulfonium salts, phosphonium salts, ammonium salts, diazonium salts, iodonium salts, and anilinium salts.

From the viewpoint of storage stability, component (D2) is, for example, an anion containing boron as a constituent element, ie, BF ₄ ^- or BR ₄ ^- (R is two or more fluorine atoms or two or more trifluoromethyl groups). represents a substituted phenyl group). The anion containing boron as a constituent element may be BR ₄ ⁻ , and more specifically may be tetrakis(pentafluorophenyl)borate.

The onium salt as component (D2) may be, for example, an anilinium salt because it has resistance to substances that can inhibit cationic curing. Examples of the anilinium salt compound include N,N-dialkylanilinium salts such as N,N-dimethylanilinium salt and N,N-diethylanilinium salt.

Component (D2) may be an anilinium salt having an anion containing boron as a constituent element. Examples of commercially available salt compounds include CXC-1821 (trade name, manufactured by King Industries).

The content of the component (D2) is, for example, 0 parts per 100 parts by mass of the component (D1) from the viewpoint of ensuring the formability and curability of the adhesive film for forming the first adhesive layer. .1 to 20 parts by weight, 1 to 18 parts by weight, 3 to 15 parts by weight, or 5 to 12 parts by weight.

From the viewpoint of ensuring the curability of the adhesive film for forming the first adhesive layer, the content of component (D) is 5% by mass or more, based on the total mass of the first adhesive layer, It may be 10% by mass or more, 15% by mass or more, or 20% by mass or more. From the viewpoint of ensuring the formability of the adhesive film for forming the first adhesive layer, the content of component (D) is 70% by mass or less, based on the total mass of the first adhesive layer, It may be 60% by weight or less, 50% by weight or less, or 40% by weight or less. When the content of component (D) is within the above range, the effects of the present disclosure tend to be significantly exhibited. Note that the content of component (D) in the composition or composition layer (based on the total mass of the composition or composition layer) may be the same as the above range.

Other components The first adhesive layer 1 further contains other components in addition to component (A), component (B), component (C) (cured product of component (C)), and component (D). You can leave it there. Examples of other components include a coupling agent (hereinafter sometimes referred to as "component (E)"), a filler (hereinafter sometimes referred to as "component (F)"), and the like.

Component (E) includes, for example, a silane coupling agent having an organic functional group such as a (meth)acryloyl group, mercapto group, amino group, imidazole group, or epoxy group, a silane compound such as tetraalkoxysilane, or a tetraalkoxytitanate derivative. , polydialkyl titanate derivatives, and the like. When the first adhesive layer 1 contains the component (E), the adhesiveness can be further improved. Component (E) may be, for example, a silane coupling agent. The content of component (E) may be 0.1 to 10% by mass based on the total mass of the first adhesive layer. Note that the content of component (E) in the composition or composition layer (based on the total mass of the composition or composition layer) may be the same as the above range.

Examples of the component (F) include non-conductive fillers (eg, non-conductive particles). Component (F) may be either an inorganic filler or an organic filler. Examples of the inorganic filler include metal oxide particles such as silica particles, alumina particles, silica-alumina particles, titania particles, and zirconia particles; inorganic particles such as metal nitride particles. Examples of the organic filler include organic fine particles such as silicone fine particles, methacrylate/butadiene/styrene fine particles, acrylic/silicone fine particles, polyamide fine particles, and polyimide fine particles. Component (F) may be, for example, silica fine particles. The content of component (F) may be 0.1 to 10% by mass based on the total mass of the first adhesive layer. Note that the content of component (F) in the composition or composition layer (based on the total mass of the composition or composition layer) may be the same as the above range.

Other Additives The first adhesive layer 1 may further contain other additives such as softeners, accelerators, deterioration inhibitors, colorants, flame retardants, and thixotropic agents. The content of other additives may be, for example, 0.1 to 10% by mass based on the total mass of the first adhesive layer. Note that the content of other additives in the composition or composition layer (based on the total mass of the composition or composition layer) may be the same as the above range.

The thickness d1 of the first adhesive layer 1 may be 5 μm or less, for example, 4.5 μm or less, 4 μm or less, 3.5 μm or less, 3 μm or less, or 2.5 μm or less. By setting the thickness d1 of the first adhesive layer 1 to 5 μm or less, the fluidity of the conductive particles during circuit connection can be further suppressed. The thickness d1 of the first adhesive layer 1 may be, for example, 0.1 μm or more or 0.7 μm or more. Note that, as shown in FIG. 1, when some of the conductive particles 4 are exposed from the surface of the first adhesive layer 1 (for example, protrude toward the second adhesive layer 2 side), the first The first adhesive layer 1 and the second adhesive layer 2 are located in the spaced apart part between the adjacent conductive particles 4, 4 from the surface 2a of the adhesive layer 1 opposite to the second adhesive layer 2 side. The distance to the boundary S (distance indicated by d1 in FIG. 1) is the thickness of the first adhesive layer 1, and the exposed portion of the conductive particles 4 is included in the thickness of the first adhesive layer 1. Not possible. The length of the exposed portion of the conductive particles 4 may be, for example, 0.1 μm or more and 5 μm or less.

Ratio of the thickness of the first adhesive layer 1 to the average particle diameter of the component (A) (conductive particles 4) (thickness of the first adhesive layer 1/average particle size of the component (A) (conductive particles 4) diameter) may be 0.50 or more, for example, 0.55 or more or 0.60 or more. When the ratio is 0.50 or more, the resin content between the opposing circuits is reduced, and it is possible to suppress an increase in connection resistance between the opposing circuits. The ratio may be, for example, 2.00 or less, 1.50 or less, 1.20 or less, 1.00 or less, or 0.80 or less.

<Second adhesive layer>
The second adhesive layer 2 may contain component (D). The (D1) component and (D2) component used in the (D) component (i.e., the second thermosetting resin component) in the second adhesive layer 2 are the (D) component in the first adhesive layer 1. Since it is the same as the component (D1) and component (D2) used in the component (that is, the first thermosetting resin component), detailed explanation will be omitted here. The second thermosetting resin component may be the same as or different from the first thermosetting resin component.

From the viewpoint of maintaining reliability, the content of component (D) (total of components (D1) and (D2)) should be 5% by mass or more and 10% by mass based on the total mass of the second adhesive layer. % or more, 15% by mass or more, or 20% by mass or more. The content of component (D) (total of components (D1) and (D2)) is determined by the total mass of the second adhesive layer from the viewpoint of preventing resin seepage problems in the reel, which is one aspect of the supply form. It may be 70% by mass or less, 60% by mass or less, 50% by mass or less, or 40% by mass or less, based on .

The second adhesive layer 2 may further contain the component (B) in the first adhesive layer 1. Here, the component (B) may not include the component (B1) and may consist only of the component (B2). That is, the second adhesive layer 2 may further contain the component (B2) as the component (B). The content of component (B) may be 1% by mass or more, 5% by mass or more, or 10% by mass or more, and 80% by mass or less, 60% by mass, based on the total mass of the second adhesive layer. or less, or 40% by mass or less.

The second adhesive layer 2 may further contain other components and other additives in the first adhesive layer 1. Preferred embodiments of other components and other additives are the same as the preferred embodiments of the first adhesive layer 1.

The content of component (E) may be 0.1 to 10% by mass based on the total mass of the second adhesive layer.

The content of component (F) may be 1% by mass or more, 10% by mass or more, or 30% by mass or more, and 90% by mass or less, 70% by mass, based on the total mass of the second adhesive layer. or less, or 50% by mass or less.

The content of other additives may be, for example, 0.1 to 10% by mass based on the total mass of the second adhesive layer.

The thickness d2 of the second adhesive layer 2 may be set as appropriate depending on the height of the electrode of the circuit member to be bonded. The thickness d2 of the second adhesive layer 2 is set to be 5 μm or more or 7 μm or more from the viewpoint of sufficiently filling the space between the electrodes and sealing the electrodes and obtaining better connection reliability. It may be 15 μm or less or 11 μm or less. Note that if a part of the conductive particles 4 is exposed from the surface of the first adhesive layer 1 (for example, protrudes toward the second adhesive layer 2 side), the first part of the conductive particles 4 in the second adhesive layer 2 The distance ( The distance indicated by d2 in FIG. 1) is the thickness of the second adhesive layer 2.

Thickness of the adhesive film 10 (total thickness of all layers constituting the adhesive film 10, in FIG. 1, the thickness d1 of the first adhesive layer 1 and the thickness of the second adhesive layer 2) The sum of d2) may be, for example, 5 μm or more or 8 μm or more, and 30 μm or less or 20 μm or less.

In the adhesive film 10 , conductive particles 4 are dispersed in the first adhesive layer 1 . Therefore, the adhesive film 10 is an anisotropic conductive adhesive film having anisotropic conductivity. The adhesive film 10 is interposed between a first circuit member having a first electrode and a second circuit member having a second electrode, and is arranged between the first circuit member and the second circuit member. It is used to electrically connect the first electrode and the second electrode to each other by thermocompression bonding.

According to the adhesive film 10, by containing the component (B1) as the component (B), the circuit connection can suppress localization of conductive particles even when heat and external force are applied. It becomes possible to form an adhesive film for

Although the adhesive film of this embodiment has been described above, the present disclosure is not limited to the above embodiment.

The adhesive film may be composed of two layers, for example, a first adhesive layer and a second adhesive layer, and the adhesive film may be composed of two layers, a first adhesive layer and a second adhesive layer. It may be composed of three or more layers. The adhesive film further includes, for example, a third adhesive layer containing a (third) thermosetting resin component, which is provided on the opposite side of the first adhesive layer from the second adhesive layer. You may be prepared. The adhesive film includes a first region formed from a first adhesive film (first adhesive layer) and a third adhesive provided adjacent to the first region. There may be a third region formed from the film (third adhesive layer). The adhesive film further includes a third region containing a (third) thermosetting resin component, which is provided adjacent to the first region on the opposite side of the second region. You can also do it.

The third adhesive layer may contain component (D). The (D1) component and (D2) component used in the (D) component (i.e., the third thermosetting resin component) in the third adhesive layer are the (D) component in the first adhesive layer 1. Since it is the same as the component (D1) and component (D2) used in (that is, the first thermosetting resin component), detailed explanation will be omitted here. The third thermosetting resin component may be the same as or different from the first thermosetting resin component. The third thermosetting resin component may be the same as or different from the second thermosetting resin component.

The content of component (D) (total of components (D1) and (D2)) is 5% based on the total mass of the third adhesive layer, from the viewpoint of imparting good transferability and peeling resistance. It may be at least 10% by mass, at least 15% by mass, or at least 20% by mass. The content of component (D) (total of components (D1) and (D2)) is determined from the viewpoint of imparting good half-cut properties and blocking resistance (suppression of resin seepage from the reel). Based on the total weight of the layer, it may be 70% by weight or less, 60% by weight or less, 50% by weight or less, or 40% by weight or less.

The third adhesive layer may further contain the component (B) in the first adhesive layer 1. Here, the component (B) may not include the component (B1) and may consist only of the component (B2). That is, the third adhesive layer may further contain component (B2) as component (B). The content of component (B) may be 10% by mass or more, 20% by mass or more, or 30% by mass or more, and 80% by mass or less, 70% by mass, based on the total mass of the second adhesive layer. or less, or 60% by mass or less.

The third adhesive layer may further contain other components and other additives in the first adhesive layer 1. Preferred embodiments of other components and other additives are the same as the preferred embodiments of the first adhesive layer 1.

The content of component (E) may be 0.1 to 10% by mass based on the total mass of the third adhesive layer.

The content of component (F) may be 1% by mass or more, 5% by mass or more, or 10% by mass or more, and 50% by mass or less, 40% by mass, based on the total mass of the third adhesive layer. or less, or 30% by mass or less.

The content of other additives may be, for example, 0.1 to 10% by mass based on the total mass of the third adhesive layer.

The thickness of the third adhesive layer may be appropriately set depending on the height of the electrode of the circuit member to be bonded. The thickness of the third adhesive layer may be 0.2 μm or more from the viewpoint of sufficiently filling the space between the electrodes and sealing the electrodes and obtaining better connection reliability. , 3 μm or less.

Moreover, the adhesive film for circuit connection of the above embodiment is an anisotropically conductive adhesive film having anisotropic conductivity, but the adhesive film for circuit connection is a conductive adhesive film that does not have anisotropic conductivity. It may also be a film.

[Method for manufacturing adhesive film for circuit connection]
The method for producing an adhesive film for circuit connection according to one embodiment includes, for example, component (A) and component (B1) (at least a part of the hydroxyl group in the phenoxy resin is modified with a group represented by formula (1)). For a composition layer consisting of a composition containing a component (B) containing a resin (resin (1))), a component (C), and a component (D) (first thermosetting resin component) A step of irradiating light to form a first adhesive layer (first step), and a second step containing component (D) (second thermosetting resin component) on the first adhesive layer. The method may also include a step of laminating two adhesive layers (second step). The manufacturing method includes forming a third adhesive layer containing component (D) (third thermosetting resin component) on the layer opposite to the second adhesive layer of the first adhesive layer. The method may further include a step of laminating (third step).

In the first step, for example, first, component (A), component (B) containing component (B1) (resin (1)), component (C), and component (D), and optionally added A varnish composition is prepared by dissolving or dispersing a composition containing other components and other additives in an organic solvent by stirring, mixing, kneading, or the like. After that, the varnish composition is applied onto the base material that has been subjected to mold release treatment using a knife coater, roll coater, applicator, comma coater, die coater, etc., and then the organic solvent is evaporated by heating and the varnish composition is applied onto the base material. A composition layer made of the composition is formed on the substrate. At this time, the thickness of the finally obtained first adhesive layer (first adhesive film) can be adjusted by adjusting the amount of the varnish composition applied. Subsequently, the composition layer made of the composition is irradiated with light to cure the component (C) in the composition layer, thereby forming a first adhesive layer on the base material. At this time, part or all of the group represented by formula (1) in resin (1) as component (B1) may be converted to the group represented by formula (1A). The first adhesive layer can be referred to as a first adhesive film.

The organic solvent used in preparing the varnish composition is not particularly limited as long as it has the property of uniformly dissolving or dispersing each component. Examples of such organic solvents include toluene, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, propyl acetate, butyl acetate, and the like. These organic solvents can be used alone or in combination of two or more. Stirring, mixing, or kneading during the preparation of the varnish composition can be performed using, for example, a stirrer, a sieve, a three-roll mill, a ball mill, a bead mill, a homodisper, or the like.

The base material is not particularly limited as long as it has heat resistance that can withstand the heating conditions used to volatilize the organic solvent. Examples of such base materials include oriented polypropylene (OPP), polyethylene terephthalate (PET), polyethylene naphthalate, polyethylene isophthalate, polybutylene terephthalate, polyolefin, polyacetate, polycarbonate, polyphenylene sulfide, polyamide, polyimide, cellulose, A base material (for example, a film) made of ethylene/vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride, synthetic rubber, liquid crystal polymer, etc. can be used.

The heating conditions for volatilizing the organic solvent from the varnish composition applied to the base material can be appropriately set according to the organic solvent used. The heating conditions may be, for example, 40 to 120° C. for 0.1 to 10 minutes.

For light irradiation in the curing step, it is preferable to use irradiation light (for example, ultraviolet light) having a wavelength within the range of 150 to 750 nm. Light irradiation can be performed using, for example, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a xenon lamp, a metal halide lamp, an LED light source, or the like. The cumulative amount of light irradiation can be set as appropriate, and may be, for example, 500 to 3000 mJ/cm ² .

The second step is a step of laminating a second adhesive layer on the first adhesive layer. The second step, for example, is the same as the first step except that component (D) and other components and other additives added as necessary are used and no light irradiation is performed. Similarly, a second adhesive layer is formed on the base material to obtain a second adhesive film. Next, the second adhesive layer can be laminated on the first adhesive layer by bonding the first adhesive film and the second adhesive film together. In addition, in the second step, for example, a varnish composition obtained using the component (D) and other components and other additives added as necessary is applied onto the first adhesive layer. The second adhesive layer can also be laminated on the first adhesive layer by coating and volatilizing the organic solvent.

Examples of methods for bonding the first adhesive film and the second adhesive film include hot pressing, roll lamination, vacuum lamination, and the like. Lamination can be performed, for example, at a temperature of 0 to 80°C.

The third step is a step of laminating a third adhesive layer on the first adhesive layer on the opposite side of the second adhesive layer. In the third step, for example, first, in the same manner as in the second step, a third adhesive layer is formed on the base material to obtain a third adhesive film. Next, by laminating a third adhesive film to the side of the first adhesive film opposite to the second adhesive film, the side of the first adhesive layer opposite to the second adhesive layer is bonded. A third adhesive layer can be laminated onto the layer. In addition, in the third step, for example, in the same manner as in the second step, a varnish composition is applied on the first adhesive layer on the side opposite to the second adhesive layer, and an organic solvent is applied. The third adhesive layer can also be laminated on the first adhesive layer by volatilizing the adhesive. The bonding method and conditions are the same as in the second step.

[Circuit connection structure and its manufacturing method]
Hereinafter, a circuit connection structure using the adhesive film 10 as a circuit connection material and a method for manufacturing the same will be described.

FIG. 2 is a schematic cross-sectional view showing one embodiment of the circuit connection structure. As shown in FIG. 2, the circuit connection structure 20 includes a first circuit board 11 and a first circuit member 13 having a first electrode 12 formed on the main surface 11a of the first circuit board 11. , a second circuit board 14, a second circuit member 16 having a second electrode 15 formed on the main surface 14a of the second circuit board 14, a first circuit member 13, and a second circuit member. 16 and electrically connects the first electrode 12 and the second electrode 15 to each other.

The first circuit member 13 and the second circuit member 16 may be the same or different. The first circuit member 13 and the second circuit member 16 may be a glass substrate or a plastic substrate on which electrodes are formed; a printed wiring board; a ceramic wiring board; a flexible wiring board; an IC chip or the like. The first circuit board 11 and the second circuit board 14 may be formed of a semiconductor, an inorganic material such as glass or ceramic, an organic material such as polyimide or polycarbonate, or a composite material such as glass/epoxy.

The first electrode 12 and the second electrode 15 are made of metals such as gold, silver, tin, ruthenium, rhodium, palladium, osmium, iridium, platinum, copper, aluminum, molybdenum, titanium, indium tin oxide (ITO), The electrode may include an oxide such as indium zinc oxide (IZO) or indium gallium zinc oxide (IGZO). The first electrode 12 and the second electrode 15 may be electrodes formed by laminating two or more of these metals, oxides, etc. The electrode formed by laminating two or more types may have two or more layers, or may have three or more layers. When the first circuit member 13 is a plastic substrate, the first electrode 12 may be an electrode having a titanium layer on the outermost surface. The first electrode 12 and the second electrode 15 may be circuit electrodes or bump electrodes. At least one of the first electrode 12 and the second electrode 15 may be a bump electrode. In FIG. 2, the first electrode 12 is a circuit electrode, and the second electrode 15 is a bump electrode.

The circuit connection portion 17 includes a cured product of the adhesive film 10. The circuit connection portion 17 may be made of a cured product of the adhesive film 10. The circuit connection portion 17 is, for example, located on the first circuit member 13 side in the direction in which the first circuit member 13 and the second circuit member 16 face each other (hereinafter referred to as “opposing direction”), and Located on the second circuit member 16 side in the opposite direction to the first cured product region 18 made of cured products of components (B), (C), and (D) other than the conductive particles 4 in the agent layer. The first electrode is interposed between a second cured product region 19 made of a cured product such as component (D) in the second adhesive layer and at least the first electrode 12 and the second electrode 15. 12 and a conductive particle 4 that electrically connects the second electrode 15 to each other. As shown in FIG. 2, the circuit connection portion 17 does not need to have two distinct regions between the first cured material region 18 and the second cured material region 19; The cured product originating from the adhesive layer and the cured product originating from the second adhesive layer may coexist to form one cured product region.

FIG. 3 is a schematic cross-sectional view showing one embodiment of a method for manufacturing a circuit connection structure. FIGS. 3(a) and 3(b) are schematic cross-sectional views showing each step. As shown in FIG. 3, in the method for manufacturing the circuit connection structure 20, between the first circuit member 13 having the first electrode 12 and the second circuit member 16 having the second electrode 15, The method includes a step of thermocompression bonding the first circuit member 13 and the second circuit member 16 with the adhesive film 10 interposed therebetween to electrically connect the first electrode 12 and the second electrode 15 to each other.

Specifically, as shown in FIG. 3A, first, a first circuit including a first circuit board 11 and a first electrode 12 formed on the main surface 11a of the first circuit board 11 is formed. A member 13, a second circuit board 14, and a second circuit member 16 including a second electrode 15 formed on the main surface 14a of the second circuit board 14 are prepared.

Next, the first circuit member 13 and the second circuit member 16 are arranged so that the first electrode 12 and the second electrode 15 face each other, and the first circuit member 13 and the second circuit member The adhesive film 10 is placed between the adhesive film 16 and the adhesive film 16 . For example, as shown in FIG. 3(a), the adhesive film 10 is laminated on the first circuit member 13 so that the first adhesive layer 1 side faces the main surface 11a of the first circuit board 11. do. Next, the adhesive film 10 is laminated onto the first electrode 12 on the first circuit board 11 and the second electrode 15 on the second circuit board 14 facing each other. A second circuit member 16 is placed on the circuit member 13.

Then, as shown in FIG. 3(b), while heating the first circuit member 13, the adhesive film 10, and the second circuit member 16, the first circuit member 13 and the second circuit member 16 are heated. By applying pressure in the thickness direction, the first circuit member 13 and the second circuit member 16 are thermocompression bonded to each other. At this time, as shown by the arrow in FIG. 3(b), since the second adhesive layer 2 has a flowable uncured thermosetting component, the distance between the second electrodes 15 is reduced. It flows to fill the voids and is cured by the heating. As a result, the first electrode 12 and the second electrode 15 are electrically connected to each other via the conductive particles 4, and the first circuit member 13 and the second circuit member 16 are bonded to each other. A circuit connection structure 20 shown in FIG. 2 can be obtained. In the method for manufacturing the circuit connection structure 20 of this embodiment, the conductive particles 4 are fixed in the first adhesive layer 1 because it can be said that the first adhesive layer 1 is partially cured by light irradiation. In addition, the first adhesive layer 1 hardly flows during the thermocompression bonding, and the conductive particles are efficiently captured between the opposing electrodes. Connection resistance between electrodes 15 is reduced. Further, by setting the thickness of the first adhesive layer to 5 μm or less, the fluidity of the conductive particles during circuit connection can be further suppressed.

The heating temperature for thermocompression bonding can be set as appropriate, and may be, for example, 50 to 190°C. Pressure is not particularly limited as long as it does not damage the adherend, but in the case of COP mounting, it may be, for example, a pressure of 0.1 to 50 MPa in terms of area at the bump electrode. Further, in the case of COG mounting, the area-converted pressure at the bump electrode may be 10 to 100 MPa, for example. These heating and pressurizing times may range from 0.5 to 120 seconds.

Hereinafter, the present disclosure will be described in more detail with reference to Examples. However, the present disclosure is not limited to these examples.

[Synthesis of resin]
(Production Example 1-1) Synthesis of Resin B1-1a In a flask equipped with a stirrer, a condenser, a thermometer, and a gas inlet tube, 400.00 g of methyl ethyl ketone and 200.00 g of toluene as solvents and phenoxy resin (FX- 293 (manufactured by Nippon Steel Chemical & Materials Co., Ltd.) (396.16 g) and stirred until uniformly dissolved. Thereafter, the temperature was raised to 60°C, and MOI-EG (2-(2-methacryloyloxyethyloxy)ethyl isocyanate), a compound represented by formula (2) in which R ¹ is a methyl group, x is 2, and y is 2 3.80 g (manufactured by Showa Denko K.K.) and 0.04 g of dioctyltin dilaurate as a catalyst were added, and the flask was stirred while blowing nitrogen to react for 2 hours to obtain the desired resin B1-1a. As described above, ¹ H-NMR was measured for Resin B1-1a, and the modification rate was calculated from the integral value of the peak in the resulting spectrum, and the modification rate of Resin B1-1a was 1%.

(Production Example 1-2) Synthesis of Resin B1-1b The resin was produced in the same manner as in Example 1-1, except that the amount of phenoxy resin charged was changed to 388.91 g and the amount of MOI-EG was changed to 11.05 g. B1-1b was obtained. The modification rate of resin B1-1b was 5%.

(Production Example 1-3) Synthesis of Resin B1-1c The resin was produced in the same manner as in Example 1-1, except that the amount of phenoxy resin charged was changed to 380.50 g and the amount of MOI-EG was changed to 19.46 g. B1-1c was obtained. The modification rate of resin B1-1c was 9%.

(Production Example 1-4) Synthesis of Resin B1-1d The resin was produced in the same manner as in Example 1-1, except that the amount of phenoxy resin charged was changed to 368.43 g and the amount of MOI-EG was changed to 31.53 g. B1-1d was obtained. The modification rate of resin B1-1d was 15%.

(Production Example 2-1) Synthesis of Resin B1-2a In a flask equipped with a stirrer, a condenser, a thermometer, and a gas inlet tube, 400.00 g of methyl ethyl ketone and 200.00 g of toluene as solvents and phenoxy resin (YP- 70 (manufactured by Nippon Steel Chemical & Materials Co., Ltd.) (396.16 g) and stirred until uniformly dissolved. Thereafter, the temperature was raised to 60°C, 3.80 g of MOI-EG (2-(2-methacryloyloxyethyloxy)ethyl isocyanate, manufactured by Showa Denko K.K.) and 0.04 g of dioctyltin dilaurate as a catalyst were added, and nitrogen was added. The inside of the flask was stirred while blowing, and the reaction was allowed to proceed for 2 hours to obtain the desired resin B1-2a. As described above, ¹ H-NMR was measured for Resin B1-2a, and the modification rate was calculated from the integral value of the peak in the resulting spectrum, and the modification rate of Resin B1-2a was 1%.

(Production Example 2-2) Synthesis of Resin B1-2b The resin was produced in the same manner as in Example 2-1, except that the amount of phenoxy resin charged was changed to 381.66 g and the amount of MOI-EG was changed to 18.30 g. B1-2b was obtained. The modification rate of resin B1-2b was 5%.

(Production Example 2-3) Synthesis of Resin B1-2c The resin was produced in the same manner as in Example 2-1, except that the amount of phenoxy resin charged was changed to 368.19 g and the amount of MOI-EG was changed to 31.77 g. B1-2c was obtained. The modification rate of resin B1-2c was 9%.

(Production Example 3-1) Synthesis of Resin B1-3a In a flask equipped with a stirrer, a condenser, a thermometer, and a gas inlet tube, 400.00 g of methyl ethyl ketone and 200.00 g of toluene as solvents and phenoxy resin (FX- 293 (manufactured by Nippon Steel Chemical & Materials Co., Ltd.) (388.91 g) and stirred until uniformly dissolved. Thereafter, the temperature was raised to 60°C, and AOI (2-(2-acryloyloxyethyloxy)ethyl isocyanate), a compound represented by formula (2) in which R ¹ is hydrogen, x is 2, and y is 1, was prepared by Showa Denko. Co., Ltd.) and 0.04 g of dioctyltin dilaurate as a catalyst were added, the inside of the flask was stirred while blowing nitrogen, and the reaction was allowed to proceed for 2 hours to obtain the desired resin B1-3a. As described above, ¹ H-NMR was measured for Resin B1-3a, and the modification rate was calculated from the integral value of the peak in the resulting spectrum, and the modification rate of Resin B1-3a was 5%.

[Preparation of first adhesive layer, second adhesive layer, and third adhesive layer]
In producing the first adhesive layer, the second adhesive layer, and the third adhesive layer, the materials shown below were used.

(A) Component: Conductive particles A-1: Uses conductive particles with an average particle size of 3.2 μm, which are Ni-plated on the surface of a plastic core body and displacement-plated with Pd on the outermost surface.

(B) component: thermoplastic resin (B1) component: resin in which at least a part of the hydroxyl groups in the phenoxy resin are modified with a group represented by formula (1) B1-1a: Production example 1-1 Resin (modification rate: 1%)
B1-1b: Resin of Production Example 1-2 (modification rate: 5%)
B1-1c: Resin of Production Example 1-3 (modification rate: 9%)
B1-1d: Resin of Production Example 1-4 (modification rate: 15%)
B1-2a: Resin of Production Example 2-1 (modification rate: 1%)
B1-2b: Resin of Production Example 2-2 (modification rate: 5%)
B1-2c: Resin of Production Example 2-3 (modification rate: 9%)
B1-3a: Resin of Production Example 3-1 (modification rate: 5%)
・(B2) component: Thermoplastic resin other than the (B1) component B2-1: FX-293 (phenoxy resin, manufactured by Nippon Steel Chemical & Materials Co., Ltd.)
B2-2: YP-70 (phenoxy resin, manufactured by Nippon Steel Chemical & Materials Co., Ltd.)
B2-3: FX-310 (phenoxy resin, manufactured by Nippon Steel Chemical & Materials Co., Ltd.)
B2-4: TOPR-300 (phenoxy resin, manufactured by Nippon Steel Chemical & Materials Co., Ltd.)
B2-5: ZX1356-2 (phenoxy resin, manufactured by Nippon Steel Chemical & Materials Co., Ltd.)

(C) component: Photocurable resin component / (C1) component: Radical polymerizable compound C1-1: A-BPEF (ethoxylated fluorene type di(meth)acrylate (bifunctional), manufactured by Shin Nakamura Chemical Co., Ltd.)
C1-2: VR-90 (bisphenol A type epoxy (meth)acrylate (bifunctional) (vinyl ester resin), manufactured by Showa Denko K.K.)
・(C2) Component: Radical photopolymerization initiator C2-1: IrgacureOXE-02 (compound having an oxime ester structure, manufactured by BASF)

(D) component: thermosetting resin component/(D1) component: cationic polymerizable compound D1-1: OXBP (oxetane compound, manufactured by Ube Industries, Ltd.)
D1-2: OXSQ (oxetane compound, manufactured by Toagosei Co., Ltd.)
D1-3: EHPE3150 (alicyclic epoxy compound, manufactured by Daicel Corporation) D1-4: CEL2021P (alicyclic epoxy compound, manufactured by Daicel Corporation)
・(D2) Component: Thermal cationic polymerization initiator D2-1: CXC-1821 (anilinium salt, manufactured by King Industries)

(E) Component: Coupling agent E-1: SH-6040 (3-glycidoxypropyltrimethoxysilane, manufactured by Dow Corning Toray Co., Ltd.)

(F) Component: Filler F-1: R805 (silica fine particles, manufactured by Evonik Industries AG)
F-2: SE2050 (silica fine particles, manufactured by Admatex Co., Ltd.)

<Preparation of first adhesive film (first adhesive layer)>
The materials shown in Tables 1 and 2 are mixed at the composition ratios shown in Tables 1 and 2 (the numbers in Tables 1 and 2 mean the nonvolatile content), and adhesive varnish diluted with an organic solvent is prepared. Obtained. Thereafter, it is coated on a release-treated PET (polyethylene terephthalate) film while applying a magnetic field, and the organic solvent is dried with hot air at 70°C for 5 minutes to form a composition containing each component. Got layers. The thickness of the composition layers 1a to 1o after drying was 2 μm, and the thickness of the composition layers 1p and 1q after drying was 6 μm. Next, the composition layers 1a to 1q are irradiated with light (UV irradiation: metal halide lamp, cumulative light amount: 1900 to 2300 mJ/cm ² ) to form the first adhesive film (first adhesive layer) 1A to 1q. Got 1Q. The first adhesive films 1A to 1Q contain a cured product of a photocurable resin component and a thermosetting resin component. The thickness of the first adhesive films (first adhesive layers) 1A to 1O was 2 μm, and the thickness of the first adhesive films (first adhesive layers) 1P and 1Q was 6 μm. .

<Preparation of second adhesive film (second adhesive layer)>
The materials shown in Table 3 were mixed at the composition ratio shown in Table 3 (the numerical values in Table 3 mean non-volatile content) to obtain an adhesive varnish diluted with an organic solvent. Thereafter, it was coated onto a PET (polyethylene terephthalate) film that had been subjected to mold release treatment. The second adhesive film 2A was applied so that the thickness after drying was 9 μm. The second adhesive film 2B was applied so that the thickness after drying was 10 μm. The second adhesive film 2C was applied so that the thickness after drying was 6 μm. Next, by drying the organic solvent etc., second adhesive films 2A to 2C containing each component were obtained. The constituent components of the second adhesive films 2A to 2C are the same.

<Third adhesive film (third adhesive layer)>
The materials shown in Table 4 were mixed at the composition ratio shown in Table 4 (the numerical values in Table 4 mean non-volatile content) to obtain an adhesive varnish diluted with an organic solvent. Thereafter, a third adhesive film 3A was obtained by coating on a PET (polyethylene terephthalate) film that had been subjected to mold release treatment and drying the organic solvent and the like. The third adhesive film 3A was applied so that the thickness after drying was 1 μm.

(Examples 1 to 9 and Comparative Examples 1 to 8)
[Preparation of adhesive film]
Adhesive films having the configurations shown in Tables 5 and 6 were produced using the first adhesive film, second adhesive film, and third adhesive film produced above. For example, in the adhesive film of Example 1, the first adhesive film 1A is laminated to the second adhesive film 2A while applying a temperature of 50 to 60°C, and the first adhesive film 1A is released from the mold. The film was peeled off. Next, a third adhesive film 3A was applied to the first adhesive film 1A exposed by peeling off the release film while applying a temperature of 50 to 60° C. to obtain the adhesive film of Example 1. Ta. For the three-layer adhesive films of Examples 2 to 5, 8, and 9 and Comparative Examples 1 to 4, 7, and 8, adhesive films having the configurations shown in Tables 5 and 6 were prepared in the same manner as in Example 1. Created. For the two-layer adhesive films of Examples 6 and 7 and Comparative Examples 5 and 6, Tables 5 and 6 were prepared in the same manner as in Example 1, except that the third adhesive film was not attached. An adhesive film having the configuration shown in was produced.

[Measurement of conductive particle density]
For the adhesive films of Examples 1 to 9 and Comparative Examples 1 to 8, the number of conductive particles per 25,000 μm ² was measured at 20 locations using a microscope and image analysis software (product name: ImagePro, manufactured by Hakuto Co., Ltd.). Then, the average value was converted into the number of conductive particles per 1 mm ² to determine the conductive particle density. The results are shown in Tables 5 and 6.

[Evaluation of localization of conductive particles]
The adhesive films of Examples 1 to 9 and Comparative Examples 1 to 8 were cut into predetermined sizes (13 mm long x 13 mm wide x about 12 μm thick) to produce evaluation films. Next, the evaluation film was pasted on a polyimide substrate with aluminum wiring (substrate thickness: 50 μm, aluminum wiring thickness: 2 μm), and a semiconductor chip with gold bumps (chip size: 10.2 mm in height x 10.2 mm in width) was attached. x thickness: 0.55 mm, bump height: approximately 9 μm, number of bumps: 184) was mounted using a flip chip mounting device (product name: FCB3-3, manufactured by Panasonic Corporation). The mounting conditions were a crimping head temperature of 190° C., a crimping time of 10 seconds, and a crimping pressure of 30 MPa. As a result, a semiconductor device was manufactured in which a polyimide substrate with aluminum wiring and a semiconductor chip with gold bumps were connected in a daisy chain. For the manufactured semiconductor device, the semiconductor chip was peeled off from the substrate using a shear force measurement device, and the degree of localization of the conductive particles in the evaluation film remaining on the semiconductor chip was observed, and the evaluation criteria were determined according to the following criteria. The evaluation was based on
A judgment: The area of the region where conductive particles are not present is less than 1% of the area of the semiconductor chip B judgment: The area of the region where conductive particles are not present is 1% or more and less than 15% of the area of the semiconductor chip C Judgment: The area of the area where conductive particles are not present is 15% or more of the area of the semiconductor chip.

[Evaluation of connection resistance]
(Preparation of circuit components)
As the first circuit member, a Ti (50 nm)/Al (400 nm) wiring pattern (pattern width: 19 μm, inter-electrode space: 5 μm) was placed on the surface of a polyimide substrate (external size: 38 mm x 28 mm, thickness: 50 μm). The formed one was prepared. As the second circuit member, an IC chip with gold bump electrodes arranged in two rows in a staggered manner (external size: 0.9 mm x 20.3 mm, thickness: 0.3 mm, bump electrode size: 70 μm x 12 μm, bump A space between electrodes: 12 μm and a bump electrode thickness: 9 μm) were prepared.

(Preparation of circuit connection structure)
Circuit connection structures were produced using the adhesive films of Examples 1 to 9 and Comparative Examples 7 and 8, which were rated A or B in the conductive particle localization evaluation. The adhesive film was placed on the first circuit member so that the first adhesive layer or the third adhesive layer of the adhesive film was in contact with the first circuit member. Using a thermocompression bonding device (BS-17U, manufactured by Ohashi Seisakusho Co., Ltd.) consisting of a stage consisting of a ceramic heater and a tool (8 mm x 50 mm), the temperature was 70°C and 0.98 MPa (10 kgf/cm ² ). The adhesive film was attached to the first circuit member by heating and pressurizing for 2 seconds, and the release film on the side of the adhesive film opposite to the first circuit member was peeled off. Next, after aligning the bump electrodes of the first circuit member and the circuit electrodes of the second circuit member, the adhesive film was heated under the conditions of an actual maximum temperature of 160° C. and an area-converted pressure of 20 MPa at the bump electrodes. The second adhesive layer of the adhesive film was attached to the second circuit member by heating and pressurizing for 5 seconds to produce a circuit connection structure.

(Evaluation of connection resistance)
Connection resistance was evaluated using the obtained circuit connection structure. The connection resistance was evaluated using a four-terminal measurement method, using the average value of the connection resistance values measured at 14 locations. A digital multimeter (7461A, manufactured by ADC Corporation) was used for the measurement. If the connection resistance value is less than 1.0Ω, it is judged as A. If the connection resistance value is 1.0Ω or more and less than 2.0Ω, it is judged as B. If the connection resistance value is 2.0Ω or more, it is judged as C. It was evaluated as a judgment. The results are shown in Tables 5 and 6.

As shown in Tables 4 and 5, the adhesive films of Examples 1 to 9 were excellent in both the evaluation of localization of conductive particles and the evaluation of connection resistance. From the above, the adhesive film of the present disclosure can suppress localization of conductive particles and reduce connection resistance even when heat and external force are applied. confirmed.

DESCRIPTION OF SYMBOLS 1... First adhesive layer, 2... Second adhesive layer, 4... Conductive particles, 5... Adhesive component, 10... Circuit connecting adhesive film (adhesive film), 11... First circuit board , 12...first electrode (circuit electrode), 13...first circuit member, 14...second circuit board, 15...second electrode (bump electrode), 16...second circuit member, 17...circuit Connection part, 20...Circuit connection structure.

Claims (11)

a first adhesive layer containing conductive particles and a thermoplastic resin;
a second adhesive layer provided on the first adhesive layer;
Equipped with
The thermoplastic resin includes a resin in which at least a portion of the hydroxyl groups in the phenoxy resin are modified with a group represented by the following formula (1) or the following formula (1A),
Adhesive film for circuit connections.

[In formula (1), R ¹ represents a hydrogen atom or a methyl group, x represents an integer of 2 to 6, and y represents an integer of 1 to 6. * indicates a bonding position that is bonded to an oxygen atom derived from a hydroxy group. ]

[In formula (1A), R ¹ , x, y, and * have the same meanings as above. *1 and *2 indicate bonding positions with carbon atoms of other radically polymerizable groups. ] The thickness of the first adhesive layer is 5 μm or less,
the ratio of the thickness of the first adhesive layer to the average particle diameter of the conductive particles is 0.50 or more;
The adhesive film for circuit connection according to claim 1. The first adhesive layer further contains a cured product of a photocurable resin component and a first thermosetting resin component,
The second adhesive layer further contains a second thermosetting resin component.
The adhesive film for circuit connection according to claim 1. The photocurable resin component includes a radically polymerizable compound and a radical photopolymerization initiator.
The adhesive film for circuit connection according to claim 3. The first thermosetting resin component and the second thermosetting resin component include a cationically polymerizable compound and a thermal cationic polymerization initiator.
The adhesive film for circuit connection according to claim 4. the cationic polymerizable compound is at least one selected from the group consisting of oxetane compounds and alicyclic epoxy compounds;
The adhesive film for circuit connection according to claim 5. The thermal cationic polymerization initiator is a salt compound having an anion containing boron as a constituent element,
The adhesive film for circuit connection according to claim 5. Further comprising a third adhesive layer containing a third thermosetting resin component, provided on the opposite side of the first adhesive layer from the second adhesive layer.
The adhesive film for circuit connection according to claim 3. The third thermosetting resin component contains a cationic polymerizable compound and a thermal cationic polymerization initiator.
The adhesive film for circuit connection according to claim 8. A circuit connecting adhesive film according to any one of claims 1 to 9 is interposed between a first circuit member having a first electrode and a second circuit member having a second electrode. and thermocompression bonding the first circuit member and the second circuit member to electrically connect the first electrode and the second electrode to each other,
A method for manufacturing a circuit connection structure. a first circuit member having a first electrode;
a second circuit member having a second electrode;
a circuit connection part that is disposed between the first circuit member and the second circuit member and electrically connects the first electrode and the second electrode to each other;
Equipped with
The circuit connection portion includes a cured product of the circuit connection adhesive film according to any one of claims 1 to 9.
Circuit connection structure.

Images