KR101139749B1 - Adhesive and bonded body - Google Patents

Abstract

[assignment]
Providing an adhesive excellent in adhesiveness after initial and reliability test even when heat-hardened at low temperature
[Workaround]
An adhesive is used which contains a silicone compound having an adhesive property, an epoxy resin, a phenoxy resin, and a curing agent. It can be set as an anisotropic conductive adhesive by containing conductive volume 0.1 volume% or more and less than 30 volume%, and it can be set as a conductive adhesive by containing 30 volume% or more and 80 volume% or less. It is preferable that the average particle diameter of electroconductive particle shall be 1-20 micrometers.

Description

Adhesives & Bonders {ADHESIVE AND BONDED BODY}

This invention relates to the adhesive agent used for the electrical connection of circuit boards, etc.

Conventionally, as an adhesive agent containing electroconductive particle, an anisotropically conductive adhesive agent and an electroconductive adhesive agent are known. Especially, an anisotropically conductive adhesive can connect the connection electrode and the to-be-connected electrode made into the target via electroconductive particle. In particular, the conductive particles are deformed to some extent by heating and pressing to connect the electrodes (connected electrodes and the electrodes to be connected). At this time, the conductive particles are dispersed at the same time to obtain a bonded body by curing the adhesive.

As an adhesive agent used for an anisotropically conductive adhesive agent, the adhesive agent using an epoxy resin, a phenoxy resin, and a latent hardening | curing agent is known (for example, patent document 1 and 2).

The connection method of a connection electrode and a to-be-connected electrode at the time of using an anisotropic conductive adhesive is demonstrated. First, an anisotropic conductive adhesive is mounted on a substrate having a connecting electrode, for example, a flexible substrate or a glass panel, and a substrate having a connected electrode, for example, an IC chip or a polyimide FPC (flexible printed wiring board) is mounted. It is a structure. Subsequently, the structure allows connection between electrodes of different substrates, while maintaining insulation between neighboring electrodes.

Certain flexible substrates, such as polyethylene terephthalate (PET) films and polycarbonates (PCs), need to be bonded at low temperatures when using film substrates with high transparency but no heat resistance.

However, when bonding at low temperature, there existed a problem that the adhesiveness of the board | substrate which has a connection electrode or the base material which has a to-be-connected electrode is inferior.

Japanese Patent Laid-Open No. 8-315885 Japanese Patent Laid-Open No. 5-320610

An object of the present invention is to overcome the above problems and to provide an adhesive having excellent adhesiveness or conductivity after initial and reliability tests, even when heat-cured at 150 ° C. or lower.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining in order to solve the said subject, the present inventors discovered that the adhesive suitable for the said objective can be obtained by containing as a component the silicone compound which has an adhesive characteristic, an epoxy resin, a phenoxy resin, and a hardening | curing agent. Thus, the present invention was completed.

That is, this invention is as follows.

(1) An adhesive comprising a silicone compound having an adhesive property, an epoxy resin, a phenoxy resin, and a curing agent

(2) Furthermore, the adhesive agent as described in (1) characterized by containing electroconductive particle.

(3) The adhesive according to (1) or (2), wherein the epoxy resin contains a tetramethylbiphenol type epoxy resin.

(4) The adhesive according to any one of (1) to (3), wherein the epoxy resin contains a dicyclopentadiene type epoxy resin.

(5) The average weight molecular weight of the said silicone compound is 1 million or less, The adhesive in any one of (1)-(4) characterized by the above-mentioned.

(6) The adhesive according to any one of (1) to (5), wherein the average weight molecular weight of the silicone compound is 600,000 or less.

(7) The adhesive according to any one of (1) to (6), wherein the silicone compound is not epoxy modified silicone.

(8) The adhesive according to any one of (1) to (7), wherein the conductive particles are conductive particles having an average particle diameter of 1 to 20 µm.

(9) The adhesive according to any one of (1) to (8), wherein the curing agent is a latent curing agent.

(10) The adhesive according to any one of (1) to (9), wherein the conductive particles contain 0.1 vol% or more but less than 30 vol% and exhibit anisotropic conductivity.

(11) The adhesive according to any one of (1) to (10), wherein the conductive particles contain 30% by volume to 80% by volume.

(12) A method for producing a joined body, wherein the adhesive according to any one of (1) to (11) is disposed on a substrate having a conductive electrode or a conductive electrode, and the electronic component is heat-pressed.

(13) A conjugate produced by the production method described in (12).

Even if the adhesive agent of this invention is heat-hardened at 150 degrees C or less at low temperature, it has the effect that it is excellent in adhesive force after an initial stage and a reliability test, or also excellent in electroconductivity.

The adhesive agent of this invention contains the silicone compound, an epoxy resin, a phenoxy resin, and a hardening | curing agent which have at least adhesive characteristics.

As a silicone compound which has adhesive characteristics, a silicone adhesive is used. It is preferable that the adhesive characteristic is 150-1800 g / inch. The conditions for evaluation of the adhesion characteristics were to apply a silicone pressure-sensitive adhesive to a polyethylene terephthalate (PET) film having a thickness of 50 μm so as to be 40 μm after curing, to prepare a pressure-sensitive adhesive sheet, and to adhere a layer of the silicone pressure-sensitive adhesive of the pressure-sensitive adhesive sheet to a stainless steel plate. It is the value at the time of peeling at 160 degree at 0.3 m / min, after leaving at 23 degreeC for 30 minutes.

As a silicone compound which has adhesive characteristics, an addition reaction type silicone adhesive and a peroxide curable silicone adhesive are mentioned, for example. An addition reaction type silicone adhesive is a silicone adhesive which has the characteristic of hardening in 80 to 120 degreeC in 1 to 5 minutes. Especially, an addition reaction type silicone adhesive is preferable. As addition reaction type silicone adhesive, Toray Dow Corning Corporation SD4580, SD4581, SD4584, SD4585, SD4586, SD4587, SD4890, SD4592, SD4560, BY24-738, BY24-740 are mentioned, for example. It is preferable that the silicone compound which has the adhesive characteristic mentioned in this invention is not epoxy modified silicone. As for the average weight molecular weight of a silicone adhesive, 1 million or less are preferable, and since 600,000 or less provide moderate adhesiveness, it is more preferable. Preferably, the average weight molecular weight is 1000 to 600,000. It is preferable to contain 0.01-20 volume% in an adhesive agent, and, as for the compounding quantity of a silicone adhesive, 0.1-15 volume% is more preferable. 0.01 volume% or more is preferable from a viewpoint of an adhesive effect expression, and 20 volume% or less is preferable from a viewpoint of preventing hardening inhibition of an epoxy resin. By using together the silicone adhesive and epoxy resin which are used in this invention, electroconductivity by the immobilization of electroconductive particle and excellent adhesive force can be satisfied simultaneously.

An epoxy resin is a compound which has two or more epoxy groups in 1 molecule, specifically, a bisphenol-A resin, bisphenol F-type resin, naphthalene-type resin, bisphenol S-type resin, phenol novolak-type resin, cresol novolak-type resin, The thing containing alicyclic type resin, biphenyl type resin, dicyclopentadiene type resin, glycidylamine type resin, glycidyl ester type resin, etc. are mentioned.

Among them, it is more preferable to include bisphenol A resin, bisphenol F resin, dicyclopentadiene type resin, and tetramethylbiphenol type resin from the viewpoint of stability under high adhesion and conductivity high humidity reliability test. It is preferable to use these resin in plurality.

As a tetramethyl biphenol type epoxy resin, YX4000K, YX4000, YX4000H, YL612H, YL6640, YL6677, etc. are mentioned, for example. The tetramethylbiphenol type epoxy resin preferably has a structure in which two biphenyl structures are bonded via an ether bond. As for the compounding quantity of tetramethyl biphenol type epoxy resin, 0.1 volume% or more and 40 volume% or less are preferable in an adhesive agent component.

Moreover, it is preferable that the adhesive agent of this invention contains a dicyclopentadiene type epoxy resin. By containing a dicyclopentadiene type epoxy resin, the fall of connection reliability can be prevented under high humidity. Moreover, when using as an anisotropically conductive adhesive agent or an electroconductive adhesive agent, it exists in the point that deterioration of the electroconductive particle by moisture absorption can also be suppressed. As for the compounding quantity of a dicyclopentadiene type epoxy resin, 1-40 volume% is preferable in an adhesive agent.

The adhesive agent of this invention contains a phenoxy resin. As a phenoxy resin, what contains molecular weight 10000-20000 or less is preferable at the solubility and the handleability. Specific examples include bisphenol A type phenoxy resins, bisphenol F type phenoxy resins, caprolactam modified phenoxy resins, and polyol modified phenoxy resins. Moreover, an acrylic resin, an epoxy modified acrylic resin, etc. can also be added and used as needed. As for the compounding quantity of phenoxy resin, 5-70 volume% is preferable in an adhesive component.

The hardening | curing agent used for the adhesive agent of this invention should just be what can harden the said epoxy resin. When performing the heat-hardening of the adhesive agent of this invention, it is more preferable to use a latent hardening | curing agent for the storage property until a use start. For example, it is preferable to use an acid anhydride, a polyamine, an amine compound, a phenol compound, and imidazole. Especially, a microcapsule hardening | curing agent is more preferable.

As for the compounding quantity of a hardening | curing agent, 5-400 volume% is preferable with respect to 100 volume% of epoxy resin total amounts, More preferably, it is 5-300 volume%.

Moreover, a well-known silane coupling agent, a titanium coupling agent, and an aluminum coupling agent can be used as needed. As a silane coupling agent, KBM403, KBE403, KBE9103, KBM9103, KBM903, KBE903, KBE573, KBM573, etc. can be used, for example. As a coupling agent, 0.01-10 volume% is preferable per 100 volume% of adhesive agents.

In addition, the adhesive agent of this invention contains electroconductive particle. As electroconductive particle, it is preferable that the average particle diameter is 1-20 micrometers. Moreover, 20 micrometers or less are preferable from a viewpoint of the handleability at the time of making into a film form as an adhesive agent. From a viewpoint of absorbing the height nonuniformity between connection electrodes at the time of a heating connection, and obtaining sufficient electrical connection, 1 micrometer-10 micrometers are more preferable in average particle diameter. More preferably, they are 2 micrometers or more and 10 micrometers or less. The average particle diameter of an electrically-conductive particle uses the value in 50% of the integrated value of the volume integrated particle size distribution measured by the laser diffraction of an airflow particle size distribution system (RODOS SR).

As the conductive particles, known conductive particles can be used. Examples of the conductive particles include particles coated with nickel, gold, copper, and silver on plastic particles, copper, silver, nickel, gold, tin, solder, lead-free solder powder, and particles plated on these particles. Can be used. Among them, metal particles, in particular copper, silver, copper or silver alloys, are preferred because they are flexible and non-destructive, and therefore connection at low pressures of 0.5 MPa or less is also possible, and does not destroy ITO or IZO electrodes on the flexible substrate. Has

The adhesive agent of this invention can be used as a conductive adhesive (henceforth an "anisotropic conductive adhesive") which can exhibit anisotropic conductivity, when it contains 0.1 volume% or more and less than 30 volume% in electroconductive particle in an adhesive agent. As for content of electroconductive particle, it is more preferable to set it as 0.5-15 volume%. The volume% of the conductive particles measures the mass of the adhesive and can be converted from specific gravity. Moreover, you may use an anisotropically conductive adhesive in any form of paste shape or film shape.

When using in film form, it is preferable that they are 10 micrometers or more and 50 micrometers or less, and, as for the thickness of an adhesive agent, it is more preferable that they are 13 micrometers or more and 35 micrometers or less.

When using in paste form, it is preferable to use after adjusting to a suitable viscosity using a suitable solvent or a reactive diluent. As a diluent, it is preferable to use the solvent which does not affect a liquid bisphenol-A epoxy resin, a bisphenol F-type epoxy resin, and a hardening | curing agent. As a solvent, it is preferable to contain toluene, ethyl acetate, (gamma) -butyrolactone, etc., for example. A solvent etc. are excluded from the injection volume% of the adhesive agent in this invention.

When connecting the base material which has a 1st conductive electrode, for example FPC, or an electronic component represented by an electronic component, for example, an IC chip, using an anisotropic conductive adhesive on the base material which has a 2nd conductive electrode, After apply | coating an appropriate amount of anisotropic conductive adhesives on a base material with a conductive electrode using a dispenser or syringe, and after adjusting the position of the counter electrode of the base material or electronic component which has a 1st conductive electrode, and the base material which has a 2nd conductive electrode, The method of hardening by heating from the base material or electronic component side which has a conductive electrode is preferable. Moreover, by this method, the joined body of the base material which has a 1st conductive electrode, and the base material which has a 2nd conductive electrode is obtained.

Also in the case of using an adhesive having an anisotropic conductivity in the form of a film, a method of attaching a film on a substrate having a second conductive electrode and curing by heating at 110 to 150 ° C. and pressing at 0.2 to 3 MPa is preferable. Do. Moreover, by this method, the joined body of the base material which has a 1st conductive electrode, and the base material which has a 2nd conductive electrode is obtained.

The electrode formed on the substrate having the first conductive electrode, the electronic component, and the substrate having the second conductive electrode may be at least one selected from ITO, copper, gold, silver, aluminum, tantalum, tin, solder, titanium, nickel, and IZ0. It is preferable that it is an electrode containing a component. In this case, the first conductive electrode and the second conductive electrode may be the same or different.

Moreover, the anisotropically conductive adhesive agent of this invention can be used also in the flexible base material in which at least one of the base material which has a 1st conductive electrode, and the base material which has a 2nd conductive electrode lacks heat resistance. The flexible base material lacking heat resistance is a base material which cannot endure heating at 160 degreeC or more, for example, PET film and PC film.

In addition, the adhesive agent of this invention can contain 30-80 volume% of conductive particles in an adhesive agent, and can be used as a conductive adhesive agent. As for content of electroconductive particle, it is more preferable to set it as 40 volume%-60 volume%.

In the case of connecting a substrate having a first conductive electrode, for example, an FPC or an electronic component represented by an electronic component, for example, an IC chip, using a conductive adhesive on a substrate having a second conductive electrode, a conductive adhesive Can be applied by coating or printing on a substrate having a first conductive electrode, an electronic component, or a substrate having a second conductive electrode by coating or printing, and a method of heating and curing at 110 to 150 ° C can be used. At this time, you may pressurize to 0.2-3 Mpa as needed. Moreover, by this method, the base material which has a 1st conductive electrode, the base material which has a 2nd conductive electrode, and the bonding body which has an adhesive agent are obtained.

For example, in the ITO electrode connection on the flexible base material using the film lacking heat resistance, even when it connected at 150 degrees C or less, the joined body which was excellent in adhesiveness was produced.

In particular, a two-layer polyimide flexible substrate having a structure in which a copper foil is laminated on a polyimide resin layer as a substrate having a connecting electrode is used, and a polyethylene terephthalate (PET) film, polycarbonate (PC), It is suitable for joining substrates using film substrates (particularly PET and PC films) having high transparency but low heat resistance, such as polyethylene naphthalate (PEN) and polyethylene sulfide (PES), using the adhesive of the present invention.

The specific example of embodiment of this invention is described below based on an Example.

The raw material component of the adhesive agent used by the Example and the comparative example is as follows.

Bisphenol A epoxy resin (manufactured by Asahi Chemical Chemicals, Ltd., AER2600)

Bisphenol F type epoxy resin (RE-303S manufactured by Nippon Kayaku Co., Ltd.)

Naphthalene type epoxy resin (manufactured by Dainippon Ink, Inc. HP-4032D)

Tetramethylbiphenol type epoxy resin (YX4000K made in Japan epoxy resin company)

Dicyclopentadiene type epoxy resin (HP7200 manufactured by Dainippon Ink Co., Ltd.)

Bisphenol A type phenoxy resin (PKHC, PKFE, PKHB manufactured by Inkemu Co., Ltd.)

Polyol modified phenoxy resin (PKHM301 manufactured by Inkemu Co., Ltd.)

Latent curing agent (HX3932HP microcapsule imidazole (as latent curing agent) manufactured by Asahi Chemicals Co., Ltd.))

Silane coupling agent (Shin-Etsu Chemical Co., Ltd. product KBM403, KBM903)

Silicone Adhesive (SD4580, SD4560 manufactured by Toray Dow Corning) (Average weight molecular weight 20-500,000)

KMP594 silicone rubber particles (manufactured by Shin-Etsu Chemical Co., Ltd.) (average weight molecular weight> 1 million)

Epoxy Modified Silicone Resin (TO16 Dow Corning, BY16-855)

Acrylic resin (Diatal manufactured by Mitsubishi Rayon)

(Conductive particles)

Silver Copper Alloy Powder Average 3 ㎛

Gold Plated Plastic Particles Average 8 μm

Gold / Nickel Plated Copper Particles Average 10 μm

<Examples 1-4, Comparative Examples 4 and 5>

Compositions 1, 2, 3, 4, 5, and 6 were applied onto a 50 μm thick PET using an ethyl acetate solvent at a ratio shown in Table 1, dried at 60 ° C. for 10 minutes in air, and a solvent of ethyl acetate. Was scattered. In this way, an anisotropically conductive adhesive having a thickness of 35 μm was prepared.

In addition, the following description was used as a test connection base material.

(Base material having first conductive electrode)

Polyimide flexible substrate with copper foil (two-layer type) (thing which performed nickel gold plating on the surface on 200 micrometer pitch copper foil wiring)

(Base material having second conductive electrode)

Substrate (300 GPa sheet resistance) on which PET electrode was formed on PET film / Example 1

Substrate (300 GPa sheet resistance) with ITO electrode formed on PET film / Example 2

Substrate (300 GPa sheet resistance) with IZO electrode formed on PC film / Example 3

Substrate (300 kW sheet resistance) with IZO electrode formed on PC film / Example 4

Base material with IZO electrode formed on PC film (300 전극 sheet resistance) / Comparative Example 4

Substrate with IZO electrode formed on PC film (300 Ω sheet resistance) / Comparative Example 5

The base material which has said 1st conductive electrode, and the base material which has a 2nd conductive electrode were bonded together using an anisotropic conductive adhesive.

Bonding is performed by attaching a film-shaped anisotropic conductive adhesive to a substrate having a second conductive electrode and heating and pressing it with a 1.5 mm head at 130 ° C., 30 seconds, and 1.5 MPa from the flexible substrate side which is the substrate having the first conductive electrode. It was.

Thus, the resistance value after the initial stage connection resistance value and the connection reliability test (after leaving for 200 hours at 85 degreeC 85%) was evaluated about the joined body thus obtained.

Connection resistance was measured by the 4-probe method using a Hioki 9455 type multimeter. The measurement measured 4 pairs of resistance of a pair of copper foil on the polyimide side, and calculated | required the average value. The results are shown in [Table 2].

About the initial stage connection resistance value, it set it as "good | favorableness" when it was 50 kPa or less, and made it "bad" when it exceeded 50 kV.

Regarding the resistance value after the connection reliability test, when the connection resistance value exceeded 100 kV, the connection reliability was "bad", and when it was 100 kV or less, the connection reliability was "good".

About the adhesion test, the adhesiveness after the initial stage adhesiveness and the said connection reliability test was measured on 90 degree peeling conditions by the tensile speed of 100 mm / min using Shimadzu Corporation Autograph AGS-50. At this time, initial adhesiveness was made into "good" the case of 0.5 kgf / cm or more, and adhesiveness after the connection reliability test was made into "good" the case of 0.4 kgf / cm or more.

<Comparative Examples 1 and 2>

Compositions 7 and 8 were prepared at the ratios shown in Table 1, applied using a bar coat on a 50 μm-thick PET film, and dried at 60 ° C. for 10 minutes to obtain a 35 μm-thick film-shaped anisotropic conductive adhesive. .

The following description was used as a test connection base material.

(Base material having first conductive electrode)

Polyimide flexible substrate with copper foil (nickel gold plating on the surface of copper foil at 200 μm pitch)

(Base material having second conductive electrode)

Base material with IZO electrode formed on PC film (300 O sheet resistance) / Comparative Example 1

Base material with IZO electrode formed on PC film (300 전극 sheet resistance) / Comparative Example 2

In the same manner as in Example 1, the substrate having the first conductive electrode and the substrate having the second conductive electrode were bonded together, and the obtained bonded body was evaluated for the initial connection resistance value and the resistance value after the connection reliability test. The results are shown in [Table 2].

<Example 7, 8>

Compositions 9 and 10 were produced at the ratio shown in Table 3, and a conductive adhesive was obtained.

The following description was used as a test connection base material.

(Base material having first conductive electrode)

Chip Capacitors / Example 7

IC (gold stud bump) / Example 8

(Base material having second conductive electrode)

Substrate (300 GPa sheet resistance) with ITO electrode formed on PET film / Example 7

Substrate With ITO Electrode Formed On PET Film (300 GPa Sheet Resistance) / Example 8

Bonding was apply | coated by apply | coating a conductive adhesive to the base material which has a 2nd conductive electrode, and heating by pressurizing with a 1.5 mm head at 130 degreeC, 60 second, and 0.5 Mpa from the said flexible base material side which is a base material which has a 1st conductive electrode.

Thus, the initial stage connection resistance value and the resistance value after the reliability test were evaluated like Example 1 about the obtained bonded body. The results are shown in [Table 4]. Similarly, the experimental result using the composition 7 is shown in the comparative example 3 of [Table 4].

As an electroconductive adhesive evaluation standard, about the initial stage connection resistance value, the case where it was 1 Pa or less was made into "good | favorableness", and the case exceeding 1 Pa was made into "bad." Regarding the resistance value after the connection reliability test (after being left for 200 hours at 85 ° C humidity of 85%), when the connection resistance value exceeds 10 kV, the connection reliability is "bad", and when it is 10 kPa or less, the connection reliability Was "good".

About the adhesive test, the initial stage adhesiveness and the adhesiveness after the said connection reliability test were measured on 90 degree peeling conditions at the tensile speed of 100 mm / min using Shimadzu Corporation Autograph AGS-50. At this time, initial adhesiveness was made into the case of 1 kgf / cm or more favorable, and adhesiveness after the connection reliability test made the case of 0.5 kgf / cm or more favorable.

The adhesive agent of this invention can be used for electronic paper, a wearable display, the flexible display of organic electroluminescent or liquid crystal, the mounting to the flexible base material of an electronic component, etc.

Claims (13)

An adhesive comprising a silicone compound having an adhesive property of 150 to 1800 g / inch, an epoxy resin, a phenoxy resin, and a curing agent. The method of claim 1,
The adhesive further contains conductive particles. The method according to claim 1 or 2,
And the epoxy resin comprises a tetramethylbiphenol type epoxy resin. The method according to claim 1 or 2,
Adhesive according to claim 1, wherein the epoxy resin comprises a dicyclopentadiene type epoxy resin. The method according to claim 1 or 2,
An adhesive having an average weight molecular weight of the silicone compound of 1 million or less. The method according to claim 1 or 2,
An adhesive having an average weight molecular weight of the silicone compound of 600,000 or less. The method according to claim 1 or 2,
Adhesives, characterized in that the silicone compound is not epoxy modified silicone. The method of claim 2,
The said electrically-conductive particle is an adhesive agent characterized by the above-mentioned electrically-conductive particle of 1-20 micrometers of average particle diameters. The method according to claim 1 or 2,
And the curing agent is a latent curing agent. The method of claim 2,
The adhesive agent containing conductive volume 0.1 volume% or more and less than 30 volume% and can show anisotropic conductivity. The method of claim 2,
The adhesive agent containing 30 volume% or more and 80 volume% or less of electroconductive particle. The joined body which has the base material which has a 1st conductive electrode, the base material which has a 2nd conductive electrode, and the adhesive agent of Claim 1 or 2. The adhesive agent of Claim 1 or 2 is arrange | positioned on the board | substrate or conductive electrode which has a conductive electrode, and the electronic component is heat-compression-bonded, The manufacturing method of the joined body characterized by the above-mentioned.