WO2018070208A1

WO2018070208A1 - Connection structure, circuit connection member, and adhesive composition

Info

Publication number: WO2018070208A1
Application number: PCT/JP2017/034153
Authority: WO
Inventors: 智樹森尻; 雅英久米; 田中　勝; 潤竹田津
Original assignee: 日立化成株式会社
Priority date: 2016-10-11
Filing date: 2017-09-21
Publication date: 2018-04-19
Also published as: TWI734841B; KR20220107095A; KR20240014613A; JP7006610B2; CN113555703A; CN113571926A; TW202139310A; CN109804508B; CN109804508A; TW201816904A; JPWO2018070208A1; TWI763551B; KR102467385B1; KR20190058614A

Abstract

The present invention provides a connection structure provided with: a first circuit member having a first circuit electrode; a second circuit member having a second circuit electrode; and a circuit connection member which is disposed between the first circuit member and the second circuit member and which electrically connects the first circuit electrode and the second circuit electrode to each other, wherein the linear thermal expansion amount L(t) of the circuit connection member at temperature (t) satisfies the condition dL(t)/dt<0 at least at a point within t = 30°C to 12°C.

Description

Connection structure, circuit connection member, and adhesive composition

The present invention relates to a connection structure, a circuit connection member, and an adhesive composition.

Conventionally, in a semiconductor element and a display element, various adhesives are used for the purpose of bonding various circuit members in the element. In addition to adhesiveness, adhesives are required to have various properties such as heat resistance and reliability in a high temperature and high humidity state. In addition, the circuit member includes, for example, a printed wiring board, an organic base material such as polyimide, or a metal having various surface states such as metal such as titanium, copper, and aluminum, ITO, IZO, IGZO, SiN, and SiO _2. Therefore, the material used for the adhesive needs to be molecularly designed according to the circuit member.

Recently, the use of non-crystalline (amorphous) ITO films, organic insulating films, and the like in circuit members has been increasing for the purpose of simplifying the manufacturing process of semiconductor elements and display elements and lowering the temperature. These film surfaces are often disadvantageous for adhesion from the physical viewpoint that surface irregularities are small, or from the chemical viewpoint that surface wettability is low.

On the other hand, in order to strengthen the adhesion between the circuit connecting member obtained by curing the adhesive and the circuit member, a covalent bond, hydrogen bond, van der Waals force is provided between the circuit connecting member and the circuit member surface. In some cases, an additive such as a coupling agent that causes an interaction such as a hydrophobic interaction due to is added to the adhesive. As the coupling agent, a silane coupling agent, a coupling agent having a phosphate group, a carboxyl group, or the like is used. For example, an epoxysilane, acryloyl group, vinyl group, or other organic functional group is present in the resin constituting the circuit connecting member, and an alkoxysilane structure or phosphorous that causes an interaction between the circuit member surface and the circuit connecting member. When a coupling agent having an acid group or the like is used, the circuit member and the circuit connecting member can be bonded more firmly (see Patent Documents 1 to 3).

JP 2003-282737 A JP 2003-277694 A JP 2013-191625 A

However, according to the study by the present inventors, when the above-described additives are used, the interaction between the circuit connecting member and the circuit member is effective depending on the type of the circuit member in a high temperature and high humidity environment. However, the circuit connecting member is peeled off from the circuit member.

Then, this invention provides the connection structure which can suppress that a circuit connection member peels from a circuit member also in a high temperature, high humidity environment, and the circuit connection member and adhesive composition which are used for this connection structure. For the purpose.

In one aspect, the present invention provides a first circuit member having a first circuit electrode, a second circuit member having a second circuit electrode, and a gap between the first circuit member and the second circuit member. And a circuit connection member that electrically connects the first circuit electrode and the second circuit electrode to each other, and the linear thermal expansion amount L (t) at the temperature t of the circuit connection member is t = 30 ° C. Provided is a connection structure that satisfies the condition of dL (t) / dt <0 at at least one temperature t of ˜120 ° C.

In another aspect, the present invention is a circuit connection member, and the linear thermal expansion amount L (t) at a temperature t of the circuit connection member is dL at at least one temperature t of t = 30 ° C. to 120 ° C. Provided is a circuit connecting member that satisfies a condition of (t) / dt <0.

The average linear thermal expansion coefficient at 30 ° C. to 120 ° C. of the circuit connecting member is preferably 500 ppm / ° C. or less.

In another aspect, the present invention provides an adhesive composition in which the linear thermal expansion amount l (t) at a temperature t of a cured product of the adhesive composition is at least one of t = 30 ° C. to 120 ° C. An adhesive composition satisfying the condition of dl (t) / dt <0 at a temperature t of

The average linear thermal expansion coefficient at 30 ° C. to 120 ° C. of the cured product is preferably 500 ppm / ° C. or less.

ADVANTAGE OF THE INVENTION According to this invention, the connection structure which can suppress that a circuit connection member peels from a circuit member also in a high temperature, high humidity environment, and the circuit connection member and adhesive composition which are used for this connection structure are provided. be able to.

It is a schematic cross section showing one embodiment of a connection structure. It is a graph which shows an example of the relationship between temperature and the amount of linear thermal expansion.

Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments. “(Meth) acrylic acid” means acrylic acid or methacrylic acid, and the same applies to other similar expressions such as (meth) acrylate.

FIG. 1 is a schematic cross-sectional view showing an embodiment of a connection structure. As shown in FIG. 1, the connection structure 1 includes a first circuit member 2, a second circuit member 3, and a circuit connection provided between the first circuit member 2 and the second circuit member 3. And a member 4.

The first circuit member 2 includes a first substrate 5 and a first circuit electrode 6 provided on the main surface of the first substrate 5. The second circuit member 3 includes a second substrate 7 and a second circuit electrode 8 provided on the main surface of the second substrate 7.

The first and

second circuit members

2 and 3 may be the same as or different from each other, and may be a chip component such as a semiconductor chip, a resistor chip, or a capacitor chip, or a substrate such as a printed circuit board. The first and

second substrates

5 and 7 may be formed of an inorganic material such as a semiconductor, glass or ceramic, an organic material such as polyimide or polycarbonate, or a composite material such as glass / epoxy. The first and

second circuit electrodes

6 and 8 may be made of gold, silver, tin, ruthenium, rhodium, palladium, osmium, iridium, platinum, crystalline or amorphous indium tin oxide (ITO), or the like. .

A large number of

circuit electrodes

6 and 8 are usually provided on the

substrates

5 and 7 of these circuit members 2 and 3 (in some cases, one may be provided). The first and

second circuit members

2 and 3 are arranged such that at least a pair of the first circuit electrode 6 and the second circuit electrode 8 face each other.

The circuit connection member 4 contains a cured product 9 of an adhesive component and conductive particles 10 dispersed in the cured product 9 of the adhesive component. By interposing the conductive particles 10 in the circuit connecting member 4 between the first circuit electrode 6 and the second circuit electrode 8 facing each other, the first circuit electrode 6 and the second circuit electrode 8 are arranged. Are electrically connected to each other.

The circuit connecting member 4 has a linear thermal expansion amount at a temperature t ° C. of the circuit connecting member 4 of L (t) μm from the viewpoint of suppressing the peeling of the circuit connecting member 4 from the

circuit members

2 and 3 and the

circuit electrodes

6 and 8. Is a circuit connecting member that satisfies the condition dL (t) / dt <0 at a temperature t of at least 30 ° C. to 120 ° C.

The linear thermal expansion amount L (t) of the circuit connecting member 4 is increased by using a thermomechanical analyzer, the length of the sample is 10 mm, the width is 4 mm, the thickness is 0.1 mm, the load is 5 gf (cross-sectional area is 0.4 mm ² ), At a temperature rate of 5 ° C./min, at a temperature t = 0 ° C. to 200 ° C., every 0.1 ° C., at a temperature t = 0 ° C., when the linear thermal expansion amount L (0) = 0 μm at the temperature t = 0 ° C. Measured as linear thermal expansion (μm). The amount of linear thermal expansion here means the amount of linear thermal expansion in the length direction of the sample.

The linear thermal expansion amount L (t) of the circuit connecting member 4 is at least any of t = 30 ° C. to 120 ° C. from the viewpoint of suppressing the peeling of the circuit connecting member 4 from the

circuit members

2 and 3 and the

circuit electrodes

6 and 8. At the temperature t, the condition of dL (t) / dt <0 is satisfied, preferably dL (t) /dt≦−0.01, more preferably dL (t) /dt≦−0.1, still more preferably Satisfies the condition of dL (t) /dt≦−0.5.

The linear thermal expansion amount L (t) of the circuit connecting member 4 is preferably t = 30 ° C. to 100 ° C. from the viewpoint of suppressing peeling of the circuit connecting member 4 from the

circuit members

2 and 3 and the

circuit electrodes

6 and 8. The above dL (t) / dt condition is satisfied at a temperature t of more preferably t = 30 ° C. to 90 ° C., and still more preferably t = 30 ° C. to 80 ° C.

The average linear thermal expansion coefficient at 30 ° C. to 120 ° C. of the circuit connecting member 4 is preferably 500 ppm / ° C. or less from the viewpoint of suppressing peeling of the circuit connecting member 4 from the

circuit members

2 and 3 and the

circuit electrodes

6 and 8. More preferably, it is 250 ppm / ° C. or less, and further preferably 150 ppm / ° C. or less.

The coefficient of linear thermal expansion (ppm / ° C.) of the circuit connecting member 4 is defined as the amount of linear thermal expansion (μm) at a length of 1 m of the circuit connecting member 4 per 1 ° C. of temperature rise. The average linear thermal expansion coefficient α _L at 30 ° C. to 120 ° C. of the circuit connecting member 4 is the linear thermal expansion amount L (t) [unit of t = 30 ° C. to 120 ° C. of the circuit connecting member 4 measured according to the above-mentioned method] : Μm / 10 mm] is converted into a linear thermal expansion amount (μm) at a length of 1 m of the circuit connecting member 4, and is calculated as an average value per 1 ° C. of temperature rise (that is, according to the following formula) from the converted value. The
α _L = {L (t = 120 ° C.) − L (t = 30 ° C.)} × 100 / (120-30)

The cured product 9 and the conductive particles 10 of the adhesive component constituting the circuit connection member 4 are selected so that the circuit connection member 4 has the above-described characteristics. The circuit connection member 4 is obtained, for example, by curing an adhesive composition containing an adhesive component and conductive particles 10. From the viewpoint of suppressing the peeling of the circuit connecting member 4 from the

circuit members

2 and 3 and the

circuit electrodes

6 and 8, the adhesive composition preferably has a linear thermal expansion amount at a temperature t of a cured product of the adhesive composition. The adhesive composition is such that l (t) satisfies a condition of dl (t) / dt <0 at a temperature t of at least t = 30 ° C. to 120 ° C. The cured product of the adhesive composition is, for example, a cured product obtained by molding the adhesive composition into a film adhesive having a thickness of 100 ± 20 μm and heating the film adhesive at 180 ° C. for 1 hour. It may be.

The linear thermal expansion amount l (t) of the cured product of the adhesive composition was determined by using a thermomechanical analyzer, the sample length 10 mm, width 4 mm, thickness 0.1 mm, load 5 gf (sample cross-sectional area 0.4 mm). ² ), at a temperature rising rate of 5 ° C./minute, at a temperature t = 0 ° C. to 200 ° C., every 0.1 ° C., and when the linear thermal expansion amount 1 (0) = 0 μm at the temperature t = 0 ° C. Is measured as a linear thermal expansion amount (μm) at a temperature of t ° C. The amount of linear thermal expansion here means the amount of linear thermal expansion in the length direction of the sample.

The linear thermal expansion amount l (t) of the cured product of the adhesive composition is a viewpoint that suppresses peeling of the cured product of the adhesive composition (circuit connection member 4) from the

circuit members

2 and 3 and the

circuit electrodes

6 and 8. Dl (t) /dt≦−0.01, more preferably dl (t) /dt≦−0.1, and even more preferably dl (t) at least at any temperature t from 30 ° C. to 120 ° C. t) /dt≦−0.5 is satisfied.

circuit members

2 and 3 and the

circuit electrodes

6 and 8. From the above, preferably at the temperature t of at least one of t = 30 ° C. to 100 ° C., more preferably t = 30 ° C. to 90 ° C., more preferably t = 30 ° C. to 80 ° C., the above dl (t) / dt Satisfy the condition of

The average coefficient of linear thermal expansion at 30 ° C. to 120 ° C. of the cured product of the adhesive composition is that the cured product of the adhesive composition (circuit connection member 4) is peeled off from the

circuit members

2 and 3 and the

circuit electrodes

6 and 8. From the viewpoint of suppression, it is preferably 500 ppm / ° C. or less, more preferably 250 ppm / ° C. or less, and still more preferably 150 ppm / ° C. or less.

The linear thermal expansion coefficient (ppm / ° C.) of the cured product of the adhesive composition is defined as the amount of linear thermal expansion (μm) at a length of 1 m of the cured product of the adhesive composition per 1 ° C. temperature increase. The average coefficient of linear thermal expansion α ₁ of the cured product of the adhesive composition at 30 ° C. to 120 ° C. is the amount of linear thermal expansion of the cured product of the adhesive composition measured at t = 30 ° C. to 120 ° C. according to the above method. The change amount of l (t) [unit: μm / 10 mm] is converted into the linear thermal expansion amount (μm) at a length of 1 m of the cured product of the adhesive composition, and the average value per 1 ° C. temperature rise from the converted value. (That is, according to the following equation).
α _l = {l (t = 120 ° C.) − l (t = 30 ° C.)} × 100 / (120-30)

The adhesive composition having such characteristics includes, for example, two or more kinds of resin components having different glass transition points (Tg), a component that easily causes phase separation, a component that has a skeleton easily oriented, a negative line Contains a filler component having a thermal expansion coefficient. Examples of combinations of components that easily cause phase separation include combinations of components that have a large difference in molecular weight, combinations of components that have a large difference in polarity, and the like. Specifically, the combinations of components that are likely to cause phase separation include a combination of an acrylic resin and an epoxy resin, a combination of a urethane resin and a phenoxy resin, a combination of an acrylic rubber and a phenoxy resin, and a combination of an acrylic rubber and an epoxy resin. It may be a combination. Examples of the component having an easily oriented skeleton include a component containing an alkyl chain and a component containing a phenyl group. When the adhesive composition contains the components as described above, the cured product (circuit connection member 4) of the resulting adhesive composition reduces minute voids due to temperature rise, reorients molecular chains, and filler components. The present inventors consider that the shrinkage (volume phenomenon) accompanying the temperature rise occurs due to the rearrangement of.

In one embodiment, the adhesive composition is preferably (a) a thermoplastic resin (hereinafter also referred to as “(a) component”) and (b) a radical polymerizable compound (hereinafter also referred to as “(b) component”). ) And (c) a radical polymerization initiator (hereinafter also referred to as “component (c)”).

The component (a) is not particularly limited, and for example, one or two selected from polyimide resin, polyamide resin, phenoxy resin, poly (meth) acrylic resin, polyester resin, polyurethane resin, polyester urethane resin and polyvinyl butyral resin. More than one type of resin may be mentioned.

The adhesive composition preferably contains two or more of the above thermoplastic resins, more preferably, from the viewpoint of easily obtaining a cured product (circuit connection member 4) of the adhesive composition having a desired amount of linear thermal expansion. Contains two or more thermoplastic resins having different Tg's. Suitable resin combinations include, for example, a combination of phenoxy resin and poly (meth) acrylic resin, a combination of phenoxy resin and polyester resin, a combination of phenoxy resin and polyester urethane resin, and a combination of phenoxy resin and polyimide resin. Combinations are mentioned.

When the adhesive composition contains two or more thermoplastic resins having different Tg, the ratio of the content of the thermoplastic resin having a higher Tg and the thermoplastic resin having a lower Tg (mass ratio: high Tg / The low Tg) is preferably 90/10 to 10/90, more preferably 90/10 to 20 from the viewpoint of easily obtaining a cured product (circuit connection member 4) of the adhesive composition having a desired amount of linear thermal expansion. / 80, more preferably 90/10 to 30/70. When the adhesive composition contains three or more thermoplastic resins having different Tg, the adhesive composition is preferably the above-mentioned thermoplastic resin having the highest Tg and the thermoplastic resin having the lowest Tg. It contains so that ratio of content may become said ratio.

The weight average molecular weight of the thermoplastic resin is preferably 5000 or more, more preferably 10,000 or more, and preferably 400,000 or less, more preferably 200000 or less, and further preferably 150,000 or less. When the weight average molecular weight of the thermoplastic resin is 5000 or more, the adhesive force of the adhesive composition tends to be improved. When the weight average molecular weight of the thermoplastic resin is 400000 or less, the compatibility with other components is excellent, and the fluidity of the adhesive tends to be improved. The weight average molecular weight in this invention means the weight average molecular weight (standard polystyrene conversion value) measured by GPC (gel permeation chromatography).

The adhesive composition may contain a rubber component as a thermoplastic resin from the viewpoint of stress relaxation and further improvement in adhesiveness. Examples of the rubber component include silicone rubber, acrylic rubber, polyisoprene rubber, polybutadiene rubber, carboxyl group-terminated polybutadiene rubber, hydroxyl group-terminated polybutadiene rubber, 1,2-polybutadiene rubber, carboxyl group-terminated 1,2-polybutadiene rubber, hydroxyl group-terminated 1 , 2-polybutadiene rubber, styrene-butadiene rubber, hydroxyl-terminated styrene-butadiene rubber, acrylonitrile-butadiene rubber, carboxylated nitrile rubber, hydroxyl-terminated poly (oxypropylene) rubber, alkoxysilyl-terminated poly (oxypropylene) rubber, poly ( Oxytetramethylene) glycol rubber, polyolefin glycol rubber, and poly-ε-caprolactone rubber. The rubber component preferably has a cyano group or a carboxyl group, which is a highly polar group, as a side chain group or a terminal group from the viewpoint of further improving adhesiveness. These rubber components can be used singly or in combination of two or more.

The rubber component may be in the form of particles. The average particle size of the rubber particles is preferably not more than twice the average particle size of the conductive particles 10, for example, 0.01 μm to 100 μm. The storage elastic modulus of the rubber particles at room temperature (25 ° C.) is preferably ½ or less of the storage elastic modulus of the conductive particles 10 and the adhesive composition at room temperature, for example, 0.1 MPa to 100 MPa. The rubber particles are preferably three-dimensionally crosslinked rubber particles from the viewpoint of excellent solvent resistance and being easily dispersed in the adhesive composition.

The content of the component (a) is preferably 20 parts by mass or more, more preferably 30 parts by mass or more, and further preferably 35 parts by mass or more with respect to 100 parts by mass of the total amount of the components (a) and (b). Moreover, it is preferably 80 parts by mass or less, more preferably 70 parts by mass or less, and still more preferably 65 parts by mass or less. When the content of the component (a) is 20 parts by mass or more, the adhesive force is further improved, and the film forming property of the adhesive composition tends to be improved. When the content is 80 parts by mass or less, the adhesive is used. There is a tendency for the fluidity of the to improve.

The component (b) is not particularly limited, and may be, for example, a compound (monomer) described below, an oligomer of the compound, or may contain both.

The component (b) is preferably a polyfunctional (meth) acrylate compound having two or more (meth) acryloyloxy groups. Such (meth) acrylate compounds include epoxy (meth) acrylate, urethane (meth) acrylate, polyether (meth) acrylate, polyester (meth) acrylate, trimethylolpropane tri (meth) acrylate, polyethylene glycol di (meth) ) Polyalkylene glycol di (meth) acrylate such as acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, neopentyl glycol di (meth) acrylate, dipentaerythritol hexa (meth) acrylate, Examples include isocyanuric acid-modified bifunctional (meth) acrylate and isocyanuric acid-modified trifunctional (meth) acrylate. As the epoxy (meth) acrylate, epoxy (meth) acrylate obtained by adding (meth) acrylic acid to two glycidyl groups of bisphenol fluorenediglycidyl ether, ethylene glycol and / or two glycidyl groups of bisphenol fluorenediglycidyl ether Examples thereof include compounds in which a (meth) acryloyloxy group is introduced into a compound to which propylene glycol has been added. Among these (meth) acrylate compounds, urethane (meth) acrylate is preferably used from the viewpoint of obtaining better adhesiveness by having a urethane bond. These compounds are used alone or in combination of two or more.

The adhesive composition may contain a monofunctional (meth) acrylate compound as the component (b) from the viewpoint of controlling fluidity. Examples of monofunctional (meth) acrylate compounds include pentaerythritol (meth) acrylate, 2-cyanoethyl (meth) acrylate, cyclohexyl (meth) acrylate, dicyclopentenyl (meth) acrylate, and dicyclopentenyloxyethyl (meth). Acrylate, 2- (2-ethoxyethoxy) ethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-hexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, Hydroxypropyl (meth) acrylate, isobornyl (meth) acrylate, isodecyl (meth) acrylate, isooctyl (meth) acrylate, n-lauryl (meth) acrylate, 2-methoxyethyl (meth) Acrylate, 2-phenoxyethyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, 2- (meth) acryloyloxyethyl phosphate, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl Examples include (meth) acrylates and glycidyl group-containing (meth) acrylates and (meth) acryloylmorpholines obtained by reacting one of the glycidyl groups of an epoxy resin having a plurality of glycidyl groups with (meth) acrylic acid. These compounds are used alone or in combination of two or more.

The adhesive composition may contain a compound having a radical polymerizable functional group such as an allyl group, a maleimide group, and a vinyl group as the component (b) from the viewpoint of improving the crosslinking rate. Examples of such compounds include N-vinylimidazole, N-vinylpyridine, N-vinylpyrrolidone, N-vinylformamide, N-vinylcaprolactam, 4,4′-vinylidenebis (N, N-dimethylaniline), Examples include N-vinylacetamide, N, N-dimethylacrylamide, N-isopropylacrylamide and N, N-diethylacrylamide.

The adhesive composition preferably contains a radically polymerizable compound having a phosphate ester structure as the component (b) for the purpose of improving the adhesive strength. The radically polymerizable compound having a phosphate ester structure may be, for example, a compound represented by the following formula (1), (2) or (3).

In the formula (1), R ¹ represents a hydrogen atom or a methyl group, R ² represents a (meth) acryloyloxy group, and a and b each independently represents an integer of 1 to 8. A plurality of R ¹ , R ² , a and b in the same molecule may be the same or different from each other.

In the formula (2), R ³ represents a (meth) acryloyloxy group, and c and d each independently represents an integer of 1 to 8. A plurality of R ³ , c and d in the same molecule may be the same or different from each other.

In formula (3), R ⁴ represents a hydrogen atom or a methyl group, R ⁵ represents a (meth) acryloyloxy group, and e and f each independently represents an integer of 1 to 8. A plurality of R ⁴ , R ⁴ , e and f in the same molecule may be the same as or different from each other.

Examples of the radical polymerizable compound having a phosphate ester structure include acid phosphooxyethyl (meth) acrylate, acid phosphooxypropyl (meth) acrylate, acid phosphooxypolyoxyethylene glycol mono (meth) acrylate, and acid phosphooxypoly Oxypropylene glycol mono (meth) acrylate, 2,2'-di (meth) acryloyloxydiethyl phosphate, EO (ethylene oxide) modified di (meth) acrylate, phosphoric acid modified epoxy (meth) acrylate and vinyl phosphate Is mentioned.

The content of the component (b) in the adhesive composition is preferably 20 parts by mass or more, more preferably 30 parts by mass or more, and still more preferably with respect to 100 parts by mass of the total amount of the components (a) and (b). Is 35 parts by mass or more, preferably 80 parts by mass or less, more preferably 70 parts by mass or less, and still more preferably 65 parts by mass or less. When the content of the component (b) is 20 parts by mass or more, the heat resistance of the cured adhesive composition (circuit connection member 4) tends to be improved, and when it is 80 parts by mass or less, high temperature and high humidity. It exists in the tendency which can further suppress peeling of the circuit connection member 4 in an environment.

When the adhesive composition contains a radical polymerizable compound having a phosphate ester structure as the component (b), the content of the radical polymerizable compound having a phosphate ester structure is the amount of the component (a) and the component (b). Preferably it is 0.1 mass part or more with respect to a total amount of 100 mass parts, More preferably, it is 0.5 mass part or more, Preferably it is 15 mass parts or less, More preferably, it is 10 mass parts or less. If the content of the radical polymerizable compound having a phosphate ester structure is 0.1 parts by mass or more, the adhesive strength of the adhesive composition tends to be further increased, and if it is 15 parts by mass or less, the adhesive composition The physical properties of the cured product (circuit connection member 4) are not easily lowered, and the reliability tends to be improved.

The component (c) can be arbitrarily selected from compounds such as peroxides and azo compounds. As the component (c), a peroxide having a 1 minute half-life temperature of 90 ° C. to 175 ° C. and a molecular weight of 180 to 1000 is preferably used from the viewpoint of excellent stability, reactivity, and compatibility. “1 minute half-life temperature” means a temperature at which the half-life of the peroxide is 1 minute. “Half-life” refers to the time it takes for the concentration of a compound to decrease to half of its initial value at a given temperature.

Examples of the radical polymerization initiator include 1,1,3,3-tetramethylbutylperoxyneodecanoate, di (4-t-butylcyclohexyl) peroxydicarbonate, and di (2-ethylhexyl) peroxydicarbonate. , Cumylperoxyneodecanoate, 1,1,3,3-tetramethylbutylperoxyneodecanoate, dilauroyl peroxide, 1-cyclohexyl-1-methylethylperoxyneodecanoate, t-hexyl Peroxyneodecanoate, t-butylperoxyneodecanoate, t-butylperoxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5- Dimethyl-2,5-di (2-ethylhexanoylperoxy) hexane, t-hexylpao Ci-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxyneoheptanoate, t-amylperoxy-2-ethylhexanoate, di-t-butyl Peroxyhexahydroterephthalate, t-amylperoxy-3,5,5-trimethylhexanoate, 3-hydroxy-1,1-dimethylbutylperoxyneodecanoate, 1,1,3,3-tetramethyl Butylperoxy-2-ethylhexanoate, t-amylperoxyneodecanoate, t-amylperoxy-2-ethylhexanoate, 3-methylbenzoyl peroxide, 4-methylbenzoyl peroxide, di ( 3-methylbenzoyl) peroxide, dibenzoyl peroxide, di (4-methylbenzo) B) Peroxide, 2,2′-azobis-2,4-dimethylvaleronitrile, 1,1′-azobis (1-acetoxy-1-phenylethane), 2,2′-azobisisobutyronitrile, , 2′-azobis (2-methylbutyronitrile), dimethyl-2,2′-azobisisobutyronitrile, 4,4′-azobis (4-cyanovaleric acid), 1,1′-azobis (1- Cyclohexanecarbonitrile), t-hexylperoxyisopropyl monocarbonate, t-butylperoxymaleic acid, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxylaurate, 2,5 -Dimethyl-2,5-di (3-methylbenzoylperoxy) hexane, t-butylperoxy-2-ethylhexyl monocarbonate T-hexylperoxybenzoate, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, t-butylperoxybenzoate, dibutylperoxytrimethyladipate, t-amylperoxynormal octoate, t It may be one or more compounds selected from amyl peroxy isononanoate and t-amyl peroxy benzoate.

From the viewpoint of suppressing the corrosion of the

circuit electrodes

6 and 8, the radical polymerization initiator preferably has a chlorine ion or organic acid content of 5000 ppm or less, and has a small amount of organic acid generated after decomposition. Is more preferably used. From the viewpoint of improving the stability of the adhesive composition, a radical polymerization initiator having a mass retention of 20% by mass or more after being left in the atmosphere at room temperature (25 ° C.) and atmospheric pressure for 24 hours is preferably used. It is done.

The content of the component (c) in the adhesive composition is preferably 1 part by mass or more, more preferably 2.5 parts by mass or more with respect to 100 parts by mass of the total amount of the components (a) and (b). Yes, and preferably 15 parts by mass or less, more preferably 10 parts by mass or less.

In another embodiment, the adhesive composition is preferably (a) a thermoplastic resin, (d) an epoxy resin (hereinafter also referred to as “component (d)”), and (e) a curing agent (hereinafter referred to as “a”). , Also referred to as “component (e)”). The component (a) in the present embodiment is the same component as the component (a) described in the above embodiment.

(D) The epoxy resin is a resin having at least one epoxy group in the molecule. Epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolak type epoxy resin, bisphenol F novolak type epoxy resin, fat Examples thereof include cyclic epoxy resins, glycidyl ester type epoxy resins, glycidyl amine type epoxy resins, hydantoin type epoxy resins, isocyanurate type epoxy resins, and aliphatic chain epoxy resins. (D) The epoxy resin may be a halogenated epoxy resin obtained by halogenating the above epoxy resin, or may be a hydrogenated epoxy resin obtained by hydrogenating the above epoxy resin. These epoxy resins, halogenated epoxy resins and hydrogenated epoxy resins are used singly or in combination of two or more.

The content of the component (d) in the adhesive composition is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, still more preferably with respect to 100 parts by mass of the total amount of the components (a) and (d). Is 30 parts by mass or more, preferably 90 parts by mass or less, more preferably 80 parts by mass or less, and still more preferably 70 parts by mass or less. When the content of the component (d) is 10 parts by mass or more, better adhesiveness tends to be obtained, and when it is 90 parts by mass or less, there is little stickiness and workability tends to be good.

(E) The curing agent (also referred to as “epoxy polymerization initiator” or “latent curing agent”) may be (d) a curing agent capable of curing the epoxy resin. Examples of the curing agent include an anion polymerizable catalyst type curing agent, a cationic polymerizable catalyst type curing agent, and a polyaddition type curing agent. These are used singly or in combination of two or more. (E) The curing agent is preferably an anion-polymerizable or cation-polymerizable catalyst-type curing agent from the viewpoint of being excellent in rapid curability and not requiring chemical equivalent consideration.

Examples of the anionic polymerizable or cationic polymerizable catalytic curing agent include imidazole curing agent, hydrazide curing agent, boron trifluoride-amine complex, onium salt such as sulfonium salt, diazonium salt, amine imide, diaminomaleonitrile, melamine And derivatives thereof, polyamine salts, dicyandiamide and the like, and these modified products can also be used.

When a compound having a tertiary amino group, an imidazole compound, or the like is used as the anionic polymerizable catalyst-type curing agent, the epoxy resin is cured by heating at a temperature of about 160 ° C. to 200 ° C. for several tens of seconds to several hours. To do. For this reason, the pot life of the adhesive composition can be made relatively long. As the cationic polymerizable catalyst-type curing agent, for example, a photosensitive onium salt (aromatic diazonium salt, aromatic sulfonium salt, etc.) that cures an epoxy resin by energy ray irradiation is preferably used. Examples of the cationic polymerizable catalyst-type curing agent that is activated by heating and cures the epoxy resin include aliphatic sulfonium salts. These anionic polymerizable or cationic polymerizable catalyst-type curing agents are preferably used in that they have fast curability.

Examples of polyaddition type curing agents include polyamines, polymercaptans, polyphenols, and acid anhydrides.

A microcapsule type curing agent obtained by coating these curing agents (latent curing agents) with a polymer compound such as polyurethane or polyester, a metal thin film such as nickel or copper, or an inorganic material such as calcium silicate. It is preferably used in that a longer pot life can be obtained.

The content of the component (e) in the adhesive composition is preferably 20 parts by mass or more, more preferably 30 parts by mass or more, with respect to 100 parts by mass of the total amount of the components (a) and (d). Moreover, Preferably it is 80 mass parts or less, More preferably, it is 70 mass parts or less.

Examples of the conductive particles 10 include metal particles such as Au, Ag, Ni, Cu, and solder, and conductive particles such as conductive carbon particles. The conductive particle 10 is a coated conductive material comprising a core composed of particles of non-conductive glass, ceramic, plastic, etc., and a layer composed of the above metal, metal particles, conductive carbon particles, etc. covering the core. It may be a conductive particle. When the conductive particles 10 are coated conductive particles or metal particles that are melted by heat (heat-melted metal particles), the conductive particles 10 are deformed by heating and pressing at the time of circuit connection. Even if there is a variation in thickness, the contact area between the conductive particles 10 and the

circuit electrodes

6 and 8 increases, and good reliability can be obtained. The conductive particles 10 prevent a short circuit between the conductive particles 10, particularly when the blending amount of the conductive particles 10 is increased, and between the adjacent

first circuit electrodes

6, 6 or the second circuit electrodes 8, Insulating coated conductive particles comprising the above-described conductive particles and an insulating coating layer formed of an insulating material such as a polymer resin, which covers the surfaces of the conductive particles, from the viewpoint of improving the insulation between the eight particles It may be. These conductive particles, coated conductive particles, and insulating coated conductive particles are used singly or in combination of two or more.

The average particle diameter of the conductive particles 10 is preferably 1 μm to 50 μm from the viewpoint of excellent dispersibility and conductivity. The content of the conductive particles is preferably 0.1% by volume or more, preferably 30% by volume or less, more preferably 10% by volume or less, based on the total amount of the adhesive composition. When the content is 0.1% by volume or more, the conductivity tends to be further improved, and when the content is 30% by volume or less, between the adjacent

first circuit electrodes

6, 6 or the second circuit electrode 8, It exists in the tendency which can suppress the short circuit between 8. The content of the conductive particles 10 is determined based on the volume of each component of the adhesive composition (before curing) at 23 ° C. As the volume of each component, for example, a value converted from weight to volume using specific gravity can be used. In addition, for example, a component that does not dissolve or swell the component in a graduated cylinder, etc., and that contains an appropriate solvent (water, alcohol, etc.) that wets the component well, is added to the component to increase the volume. It can also be determined as a volume.

In addition to the component (a), the component (b), the component (c) and the conductive particles 10, the adhesive composition is added to the component (a), the component (d), the component (e) and the conductive particles 10. , Other resins such as phenol resin, melamine resin, filler (filler), softener, curing accelerator, anti-aging agent, colorant, flame retardant, thixotropic agent, coupling agent, etc., You may further contain a thickener, a leveling agent, a weather resistance improvement agent, an isocyanate compound, etc.

The filler (filler) is composed of silicon, calcium, zirconium, titanium, aluminum, carbon, bismuth, cobalt, copper, iron, indium, manganese, tin, yttrium, zinc or the like, a compound containing them, an organic compound, or the like. Particles. The average particle diameter of the particles is preferably ½ or less of the average particle diameter of the conductive particles 10, for example, 0.005 μm to 25 μm. When the adhesive composition contains non-conductive particles (for example, the rubber particles), the average particle size of the particles used as the filler is equal to or less than the average particle size of the non-conductive particles. Good.

The filler is preferably from the viewpoint of further improving electrical characteristics such as connection reliability between the

circuit electrodes

6 and 8 by a cured product (circuit connection member 4) of the adhesive composition having a desired amount of linear thermal expansion. The filler has a negative average linear thermal expansion coefficient at 30 ° C. to 120 ° C. Examples of the filler having a negative average linear thermal expansion coefficient at 30 ° C. to 120 ° C. include particles composed of a zirconium-based compound.

The content of the filler is preferably 5 parts by mass or more and preferably 60 parts by mass or less with respect to 100 parts by mass of the adhesive composition. When the content is 60 parts by mass or less, the effect of improving the connection reliability tends to be obtained more sufficiently, and when the content is 5 parts by mass or more, the effect of adding the filler tends to be sufficiently obtained.

The coupling agent may be, for example, a silane coupling agent. By using a coupling agent such as a silane coupling agent, the adhesion of the adhesive composition can be further improved. Examples of the silane coupling agent include vinyltrimethoxysilane, vinyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3- (meth) acryloxypropylmethyldimethoxy. Silane, 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropylmethyldiethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, N-2- (aminoethyl) -3- Aminopropylmethyldimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, and condensates thereof And the like.

The content of the coupling agent is preferably 0.1 parts by mass or more, more preferably 0.25 parts by mass with respect to 100 parts by mass of the adhesive components (for example, components (a) to (e)) of the adhesive composition. Part or more, preferably 10 parts by mass or less, more preferably 5 parts by mass or less. When the content of the coupling agent is 0.1 parts by mass or more, the occurrence of peeling between the circuit member and the circuit connection member tends to be further suppressed, and the content of the coupling agent is 10 parts by mass or less. The pot life of the adhesive composition tends to be long.

When the adhesive composition is liquid at 15 to 25 ° C., for example, it can be used as a paste adhesive composition. When the adhesive composition is solid at room temperature (25 ° C.), it can be used as a paste adhesive composition by heating, or it can be dissolved in a solvent and used as a paste adhesive composition. The solvent is not particularly limited as long as it is not reactive with the components contained in the adhesive composition and the components contained in the adhesive composition exhibit sufficient solubility, but has a boiling point of 50 at atmospheric pressure. A solvent having a temperature of from 150 ° C. to 150 ° C. is preferably used. When the boiling point is 50 ° C. or higher, the solvent can be prevented from volatilizing at room temperature (25 ° C.), and use in an open system becomes easy. When the boiling point is 150 ° C. or lower, the solvent is easily volatilized after the adhesive composition is applied to the

circuit members

2 and 3, and the reliability after bonding can be ensured.

The adhesive composition can also be used as a film adhesive. The adhesive composition is, for example, a solution obtained by adding a solvent or the like to the adhesive composition, if necessary, on a peelable substrate such as a fluororesin film, a polyethylene terephthalate film, a release paper, or a substrate such as a nonwoven fabric. The solution is impregnated with and placed on a peelable substrate, and then the solvent is removed to form a film. The film adhesive is preferably used from the viewpoint of handleability and the like.

The adhesive composition is used as a semiconductor element adhesive material typified by anisotropic conductive adhesive, silver paste, circuit connection material typified by silver film, CSP elastomer, CSP underfill material, LOC tape, etc. be able to.

In the connection structure 1, for example, the first circuit member 2 and the second circuit member 3 are arranged so that the first circuit electrode 6 and the second circuit electrode 8 face each other, A film adhesive is interposed between the circuit member 2 and the second circuit member 3, and these are heated and pressurized to electrically connect the first circuit electrode 6 and the second circuit electrode 8 to each other. Can be obtained.

The heating temperature during heating is not particularly limited, but is preferably 50 ° C to 250 ° C. The pressure at the time of pressurization is not particularly limited as long as it does not damage the adherend (circuit members 2 and 3), but is preferably 0.1 MPa to 10 MPa. Heating and pressurization are preferably performed for 0.5 seconds to 3 hours.

When connecting the

circuit members

2 and 3, light irradiation may be performed simultaneously with heating and pressurization from the viewpoint of connection at a lower temperature and in a shorter time. For light irradiation, irradiation light having a wavelength range of 150 nm to 750 nm is preferably used. Light irradiation, for example, low pressure mercury lamp, medium pressure mercury lamps, high pressure mercury lamp, ultra-high pressure mercury lamp, using a xenon lamp or a metal halide lamp, may be carried out in dose of ^{0.1J / cm 2 ~ 10J / cm} 2.

The cured product (circuit connection member 4) of the adhesive composition described above has a dl (t) / dt <0 (dL) at a temperature t = 30 ° C. to 120 ° C., for example, as indicated by L1 in FIG. Since the cured product (circuit connection member) is such that t satisfying (t) / dt <0), the amount of thermal expansion of the circuit connection member 4 itself accompanying a temperature rise can be reduced, and the circuit connection member 4 is reduced at the interface stress between the substrate 4 and the

substrates

5 and 7 and the circuit electrodes 6 and 8 (stress for peeling the circuit connection member 4 from the

substrates

5 and 7 and the circuit electrodes 6 and 8). It becomes possible.

On the other hand, a cured product (circuit connection member) of a conventional adhesive composition is always dl (t) / dt ≧ 0 (dL () at a temperature t = 30 ° C. to 120 ° C., as indicated by L2 in FIG. t) / dt ≧ 0), which is a cured product (circuit connection member) of the adhesive composition, the circuit connection member 4 itself is likely to thermally expand as the temperature rises, and the circuit connection member 4 and the

substrate

5 , 7 and

circuit interface

6, 8, a large peeling interface stress is generated.

Therefore, the hardened | cured material (circuit connection member 4) of the adhesive composition which concerns on this embodiment is a case where it puts in a high-temperature, high-humidity environment compared with the hardened | cured material (circuit connection member) of the conventional adhesive composition. Even so, the circuit connecting member 4 can be prevented from being peeled off from the

substrates

5 and 7 and the

circuit electrodes

6 and 8. Such an effect is exhibited even when the

circuit electrodes

6 and 8 are circuit electrodes formed of amorphous ITO or the like, which is disadvantageous for adhesion.

Hereinafter, the present invention will be described more specifically based on examples, but the present invention is not limited to the examples.

<Synthesis of polyurethane resin>
To a separable flask equipped with a reflux condenser, a thermometer, and a stirrer, 1000 parts by mass of polypropylene glycol (number average molecular weight: 2000), which is a diol having an ether bond, and 4000 parts by mass of methyl ethyl ketone as a solvent are added. Stir for 30 minutes. After this solution was heated to 70 ° C., 0.127 parts by mass of dimethyltin laurate as a catalyst was added. Next, a solution prepared by dissolving 125 parts by mass of 4,4′-diphenylmethane diisocyanate in 125 parts by mass of methyl ethyl ketone was added dropwise to this solution over 1 hour. Thereafter, stirring was continued at 70 ° C. until an absorption peak derived from the NCO group was not observed with an infrared spectrophotometer, to obtain a methyl ethyl ketone solution of a polyurethane resin. And the quantity of methyl ethyl ketone was adjusted so that the solid content concentration (polyurethane resin concentration) of this solution might be 30 mass%.

The glass transition temperature (Tg) of the obtained polyurethane resin was −20 ° C. The glass transition temperature (Tg) was measured using a thermomechanical analyzer.

The weight average molecular weight of the obtained polyurethane resin was 320,000. The weight average molecular weight is a standard polystyrene equivalent value measured by GPC (gel permeation chromatography). The GPC analysis conditions are shown in Table 1 below.

<Synthesis of urethane acrylate>
Into a 2-liter four-necked flask equipped with a thermometer, stirrer, inert gas inlet, and reflux condenser, 4000 parts by weight of polycarbonate diol (manufactured by Aldrich, number average molecular weight: 2000), 2-hydroxyethyl A reaction solution was prepared by charging 238 parts by mass of acrylate, 0.49 parts by mass of hydroquinone monomethyl ether, and 4.9 parts by mass of a tin-based catalyst. To the reaction liquid heated to 70 ° C., 666 parts by mass of isophorone diisocyanate (IPDI) was uniformly dropped over 3 hours to be reacted. After completion of dropping, the reaction was continued for 15 hours, and it was confirmed that the NCO group content was 0.2% by mass or less using a potentiometric automatic titrator (product name AT-510, manufactured by Kyoto Electronics Industry Co., Ltd.). At the time, the reaction was terminated to obtain urethane acrylate. The weight average molecular weight of urethane acrylate was 8500. In addition, the weight average molecular weight of urethane acrylate was measured similarly to the weight average molecular weight of the above-mentioned polyurethane resin.

<Production of film adhesive>
The components shown below were mixed at a mass ratio shown in Tables 2 and 3 to obtain an adhesive composition.

(Thermoplastic resin)
A1: Phenoxy resin (product name: PKHC, manufactured by Union Carbide, weight average molecular weight 45000, Tg: 90 ° C., bisphenol A skeleton)
A2: Phenoxy resin (Product name: YD-6020, manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., weight average molecular weight 5000, Tg: 70 ° C., bisphenol A / bisphenol F skeleton)
A3: Phenoxy resin (product name: FX-316, manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., weight average molecular weight 50000, Tg: 70 ° C., bisphenol F skeleton)
A4: Phenoxy resin (product name: FX-293AT40, manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., Tg: 160 ° C., high heat resistant skeleton)
A5: Polyurethane resin synthesized as described above A6: Polyester resin (Product name: UE-3400, manufactured by Unitika Ltd., Tg: −20 ° C.)
A7: Polyester resin (Product name: UE-3200, manufactured by Unitika Ltd., Tg: 70 ° C.)
(Radically polymerizable compound)
B1: Urethane acrylate synthesized as described above B2: Isocyanuric acid EO-modified diacrylate (Product name: M-215, manufactured by Toa Gosei Co., Ltd.)
B3: 2-Methacryloyloxyethyl acid phosphate (Product name: Light Ester P-2M, manufactured by Kyoeisha Chemical Co., Ltd.)
In addition, about the solid component among the above components, it was used after making 40 mass% solution prepared by dissolving 40 g of solid components in 60 g of methyl ethyl ketone.

(Radical polymerization initiator)
C1: Lauroyl peroxide (Product name: Parroyl L, manufactured by NOF Corporation, molecular weight 398.6)
(Filler)
D1: Silica fine particles (Product name: R104, manufactured by Nippon Aerosil Co., Ltd., primary particle size: 12 nm)
(Silane coupling agent)
E1: 3-methacryloxypropyltrimethoxysilane (Product name: KBM-503, manufactured by Shin-Etsu Chemical Co., Ltd.)
In addition, about the silica fine particle, it used, after making 10 mass% dispersion liquid prepared by disperse | distributing 10 g of silica fine particles in the mixed solvent of 45 g of toluene and 45 g of ethyl acetate.

Next, conductive particles having an average particle diameter of 5 μm and a specific gravity of 2.5 having a nickel layer having a thickness of 0.2 μm were prepared on the surface of polystyrene particles (nuclei). This electroconductive particle was disperse | distributed to each adhesive composition in the ratio of 1.5 volume%, and the coating liquid was obtained. This coating solution was applied to a polyethylene terephthalate (PET) film having a thickness of 50 μm using a coating apparatus. The coating film was dried with hot air at 70 ° C. for 10 minutes to obtain a film adhesive having a thickness of 18 μm.

<Production of connection structure>
A flexible circuit board (FPC) having about 2200 copper circuit electrodes having a line width of 75 μm, a pitch of 150 μm and a thickness of 18 μm, and a glass (SiO ₂ ) substrate (product name: Preclin slide S7224, manufactured by Matsunami Glass Industrial Co., Ltd.), or Each said film adhesive was arrange | positioned between the glass substrate with a thin film of amorphous indium tin oxide (ITO) (made by Geomatech), and FPC and the glass substrate or the glass substrate with amorphous ITO were connected. The connection was made by heating and pressurizing at 160 ° C. and 3 MPa for 5 seconds using a thermocompression bonding apparatus (heating method: constant heat type, manufactured by Toray Engineering Co., Ltd.). The pressure at the time of pressurization was calculated by setting the pressure-bonding area to 0.495 cm ² . As a result, a connection structure was obtained in which the FPC and the glass substrate or the glass substrate with amorphous ITO were connected over a width of 1.5 mm by a cured product of the film adhesive.

<Measurement of linear thermal expansion>
A plurality of the film adhesives thus prepared were bonded together using a laminator so as to have a thickness of 100 ± 20 μm, and heated at 180 ° C. for 1 hour in an oven to prepare a cured product sample. About the cured product sample, using a thermomechanical analyzer (manufactured by Shimadzu Corporation), the length of the sample is 10 mm, the width is 4 mm, the load is 5 gf (per sample cross-sectional area of 0.4 mm ² ), and the heating rate is 5 ° C./min. Under these conditions, the linear thermal expansion amount l (t) μm at a temperature t = 0 ° C. to 200 ° C. was measured every 0.1 ° C. The linear thermal expansion amount l (t) was measured by setting the linear thermal expansion amount l (0) at a temperature t = 0 ° C. to 0 μm. From the measurement results, the presence / absence of a temperature region where dl (t) / dt <0 at temperatures t = 30 ° C. to 120 ° C. (if present, the temperature region and the minimum value of dl (t) / dt) was confirmed. . Further, from the measurement results, an average linear thermal expansion coefficient (ppm / ° C.) at 30 ° C. to 120 ° C. was calculated. The results are shown in Tables 2 and 3.

<Evaluation of presence or absence of peeling>
About the connection structure produced as described above, the connection appearance after the high-temperature and high-humidity test immediately after connection and after being left in a constant temperature and humidity chamber of 85 ° C. and 85% RH for 250 hours is observed using an optical microscope. The peeling occurrence area of the substrate-resin interface in the space portion (the portion between the electrode terminals of the FPC) was measured. The case where the peeling occurrence area in the entire space exceeded 30% was evaluated as “existing”, and the case where it was 30% or less was evaluated as “no” peeling. The results are shown in Tables 2 and 3.

From the above, it was confirmed that the circuit connection members of Examples 1 to 7 can suppress the occurrence of peeling even under high temperature and high humidity conditions as compared with the circuit connection members of Comparative Examples 1 to 9.

DESCRIPTION OF SYMBOLS 1 ... Connection structure, 2 ... 1st circuit member, 3 ... 2nd circuit member, 4 ... Circuit connection member, 6 ... 1st circuit electrode, 8 ... 2nd circuit electrode, 10 ... Conductive particle | grains.

Claims

A first circuit member having a first circuit electrode;
A second circuit member having a second circuit electrode;
A circuit connection member provided between the first circuit member and the second circuit member and electrically connecting the first circuit electrode and the second circuit electrode to each other;
A connection structure in which an amount of linear thermal expansion L (t) at a temperature t of the circuit connection member satisfies a condition of dL (t) / dt <0 at a temperature t of at least 30 ° C. to 120 ° C.
2. The connection structure according to claim 1, wherein an average linear thermal expansion coefficient at 30 ° C. to 120 ° C. of the circuit connection member is 500 ppm / ° C. or less.
A circuit connecting member,
The circuit connecting member, wherein a linear thermal expansion amount L (t) at a temperature t of the circuit connecting member satisfies a condition of dL (t) / dt <0 at at least any temperature t of t = 30 ° C. to 120 ° C.
4. The circuit connection member according to claim 3, wherein the circuit connection member has an average coefficient of linear thermal expansion at 30 ° C. to 120 ° C. of 500 ppm / ° C. or less.
An adhesive composition comprising:
The linear thermal expansion amount l (t) at a temperature t of the cured product of the adhesive composition satisfies a condition of dl (t) / dt <0 at a temperature t of at least t = 30 ° C. to 120 ° C. Adhesive composition.
6. The adhesive composition according to claim 5, wherein the cured product has an average coefficient of linear thermal expansion at 30 ° C. to 120 ° C. of 500 ppm / ° C. or less.