WO2019188372A1

WO2019188372A1 - Conductive material and connecting body manufacturing method

Info

Publication number: WO2019188372A1
Application number: PCT/JP2019/010673
Authority: WO
Inventors: 宏治北爪; 康二江島
Original assignee: デクセリアルズ株式会社
Priority date: 2018-03-30
Filing date: 2019-03-14
Publication date: 2019-10-03
Also published as: JP2019179647A; CN111886657A; CN117877784A; KR102517498B1; JP2022173197A; KR20200110393A; TW202001932A; CN116364328A; JP7420883B2

Abstract

Provided are an anisotropic conductive adhesive with which it is possible to obtain high connection reliability even in the case of pressure bonding under a low pressure condition, and a connecting body manufacturing method. The anisotropic conductive adhesive contains an insulating adhesive and resin core conductive particles having a 20% compression recovery rate of 20% or more and a compression hardness K-value of 4000 N/mm² or more during 20% compression. This makes it possible that the conductive particles break through an oxide layer even in the case of pressure bonding under a low pressure condition, similarly to the case of pressure bonding under a high pressure condition, thereby making it possible to obtain high connection reliability.

Description

Conductive material and connection body manufacturing method

This technology relates to a conductive material for connecting, for example, an IC (Integrated Circuit) chip and a flexible wiring board, and a method for manufacturing a connection body. This application claims priority on the basis of Japanese Patent Application No. 2018-067630 filed on Mar. 30, 2018 in Japan. This application is incorporated herein by reference. Incorporated.

Conventionally, for example, in an active matrix type display device such as an LCD (Liquid Crystal Display) or an OLED (Organic Light Emitting Diode) display, a plurality of scanning signal lines and image signal lines intersecting each other are formed on an insulating substrate such as glass. In addition to being arranged in a matrix, thin film transistors (hereinafter referred to as “TFT”) are arranged and formed at the intersections of the scanning signal lines and the image signal lines.

For metal wiring films for electrodes such as a source electrode and a drain electrode of TFT, IZO (Indium Zinc Oxide) is used instead of ITO (Indium Tin Oxide), which has a high production cost. The IZO wiring has a smooth surface, and an oxide layer (passive) is formed on the surface. For example, in an aluminum wiring, a protective layer of an oxide layer such as TiO ₂ may be formed on the surface in order to prevent corrosion. Alternatively, Al / Ti wiring may be used, but this may be the same as aluminum wiring.

However, since the oxide layer is hard, for example, when the driver IC is connected with an anisotropic conductive adhesive, the connection resistance value tends to increase.

Therefore, for example, in Patent Document 1, by reducing the compression recovery rate of the conductive particles and suppressing the repulsive force of the conductive particles, peeling between the electrode and the circuit connection material is suppressed, and good connection reliability is achieved. It has been proposed to obtain.

JP 2016-1562 A

However, in the method described in Patent Document 1, since the compression recovery rate of the conductive particles is low, the contact area with the wiring tends to be small, and the conduction resistance value tends to be high. For this reason, in the method described in Patent Document 1, high connection reliability cannot be obtained unless pressure bonding is performed under high pressure conditions, and there is a concern about damage to mounted components.

The present technology solves the above-described problems, and provides a conductive material that can obtain high connection reliability even under pressure bonding under low pressure conditions, and a method for manufacturing a connection body.

As a result of intensive studies, the present inventors have found that by using resin core conductive particles having a reasonably high compression recovery rate and hardness that breaks through the oxide layer, high connection reliability can be obtained even under pressure bonding under low pressure conditions. Based on this, this technology has been completed.

That is, the conductive material according to the present technology includes an insulating adhesive and resin core conductive particles having a compression recovery rate of 20% or more and a compression hardness K value at 20% compression of 4000 N / mm ² or more. contains.

Moreover, the manufacturing method of the connection body according to the present technology includes an insulating adhesive and a resin core conductive material having a compression recovery rate of 20% or more and a compression hardness K value at 20% compression of 4000 N / mm ² or more. An arrangement step of arranging the first electronic component and the second electronic component via a conductive material containing particles, and the second electronic component is crimped to the first electronic component by a crimping tool; A curing step of curing the conductive material.

In addition, a connection body according to the present technology includes a first electronic component, a second electronic component, and an adhesive film in which the first electronic component and the second electronic component are bonded to each other. The film is formed by curing a conductive material containing an insulating adhesive and a resin core conductive particle having a compression recovery rate of 20% or more and a compression hardness K value at 20% compression of 4000 N / mm ² or more. It becomes.

According to the present technology, the resin core conductive particles can break through the oxide layer even under pressure bonding under a low pressure condition, and the contact area with the wiring can be increased, so that high connection reliability can be obtained.

FIG. 1 is a cross-sectional view schematically showing a connection body manufacturing method according to the present embodiment. FIG. 1 (A) shows an arrangement step (S1), and FIG. 1 (B) shows a curing step ( S2).

Hereinafter, embodiments of the present technology will be described in detail in the following order with reference to the drawings.
1. 1. Conductive material 2. Manufacturing method of connected body Example

<1. Conductive material>
The conductive material according to the present embodiment includes an insulating adhesive and resin core conductive particles having a compression recovery rate of 20% or more and a compression hardness K value at 20% compression of 4000 N / mm ² or more. contains. As a result, the resin core conductive particles can break through the oxide layer even under pressure bonding under low pressure conditions, and the contact area between the resin core conductive particles and the wiring can be increased, so that high connection reliability can be obtained. . This is because the wiring is crushed and deformed by the high compression recovery rate and the compression hardness K value at 20% compression, and the followability is improved, so that the contact area with the wiring is increased and at the time of high 20% compression This is considered to be because the oxide layer can be broken through by the compression hardness K value.

Examples of the conductive material include a film shape and a paste shape, and examples thereof include an anisotropic conductive film (ACF) and an anisotropic conductive paste (ACP). In addition, examples of the curing type of the conductive material include a thermosetting type, a photocuring type, a photothermal combined curing type, and the like, and can be appropriately selected depending on the application.

Hereinafter, a thermosetting anisotropic conductive film having a two-layer structure in which a conductive particle-containing layer containing resin core conductive particles and a conductive particle non-containing layer not containing resin core conductive particles are laminated will be described as an example. explain. In addition, as the thermosetting anisotropic conductive film, for example, a cation curable type, an anion curable type, a radical curable type, or a combination thereof can be used. Here, an anion curable anisotropic conductive film is used. Will be described.

An anisotropic conductive film shown as a specific example includes a resin core conductive particle, a conductive particle-containing layer containing a film-forming resin, an epoxy resin, and an anionic polymerization initiator as an insulating adhesive, and an insulating adhesive. As a conductive particle non-containing layer containing a film-forming resin, an epoxy resin, and an anionic polymerization initiator.

[Resin core conductive particles]
The compression recovery rate of the resin core conductive particles is 20% or more, more preferably 45% or more, still more preferably 60% or more, and the upper limit of the compression recovery rate is about 90%. If the compression recovery rate is higher than a certain level, the contact state between the resin core conductive particles and the bumps and wiring electrodes sandwiching the resin core conductive particles after connection is easily maintained. However, depending on the combination with the compression hardness K value, a high pressure is required for connection.

The compression hardness K value at 20% of the resin core conductive particles compression is a 4000 N / mm ² or more, more preferably 8000 N / mm ² or more, more preferably 10000 N / mm ² or more, 20 The upper limit of the compression hardness K value at% compression is preferably less than 22000 N / mm ² , more preferably 20000 N / mm ² or less. If the compression hardness K value is higher than a certain value, the resin core conductive particles break through the insulating layer on the surface of the wiring electrode at the time of connection, and a resistance value is easily obtained. However, depending on the combination with the compression recovery rate, a high pressure is required for connection.

A preferred combination of the compression recovery rate of the resin core conductive particles and the compression hardness K value at 20% compression is 20% or more, and the compression hardness K value at 20% compression is 4000 N / mm ² or more. The compression recovery rate is 45% or more, the compression hardness K value at 20% compression is 4000 N / mm ² or more, the compression recovery rate is 45% or more, and the compression hardness K value at 20% compression is 8000 N. / Mm ² or more, or the compression recovery rate is 60% or more, and the compression hardness K value at 20% compression is 8000 N / mm ² or more. Thereby, for example, in pressure bonding of about 130 MPa, an increase in the resistance value after the reliability test can be suppressed, and high connection reliability can be obtained. It is desired that the pressure be reduced due to circumstances such as demands for thinning and bending (flexibility) of electronic components. In addition, when connecting continuously (producing a connection body), it is expected that the pressure is not always constant. Therefore, it is desirable that a good connection state be obtained even if the pressure condition varies. For example, it can be used preferably in the range of 130 MPa to 80 MPa, and more preferably in the range of 130 MPa to 50 MPa. In particular, if it can be used in the range of 80 MPa to 50 MPa, it becomes easy to meet the above-mentioned demands for thinning and flexibility of electronic components. This does not necessarily indicate that the connection may vary within the above-described range when continuously connected, but merely states that if the connection can be made within this range, the variation at the time of continuous connection can be tolerated to some extent. This permissible level varies depending on combinations such as connection conditions, electronic component conditions, and continuous connection apparatus conditions, and may be adjusted as appropriate.

The compression recovery rate of the resin core conductive particles can be measured as follows. Using a micro-compression tester, the resin core conductive particles are compressed with the end face of a cylindrical indenter (diameter 50 μm, made of diamond), and the displacement from the initial load (load 0.4 mN) to the load reversal (load 5 mN) The compression recovery rate can be a value of L1 / L2 × 100 (%), where L2 is L1, and the displacement from the load reversal to the final load (load 0.4 mN) is L1.

Moreover, the compression hardness K value (20% K value) at the time of 20% compression of the resin core conductive particles can be measured as follows. Using a micro-compression tester, the resin core conductive particles are compressed under the conditions of a compression speed of 2.6 mN / sec and a maximum test load of 10 gf on a cylindrical indenter end face (diameter 50 μm, made of diamond). The load value (N) and compression displacement (mm) at this time are measured. From the measured value obtained, the 20% K value can be determined by the following formula. As the micro compression tester, for example, “Fischer Scope H-100” manufactured by Fischer is used. K value (N / mm ² ) = (3/2 ^1/2 ) · F · S ⁻³ / ² · R ^−1/2
F: Load value when the conductive particles are 20% compressively deformed (N)
S: Compression displacement (mm) when conductive particles are 20% compressively deformed
R: radius of conductive particles (mm)

Resin core conductive particles include resin core particles and a conductive layer covering the resin core particles. The resin core conductive particles include a resin core particle, a plurality of resin core particles arranged on the surface of the resin core particle, and forming a protrusion, and a resin core particle and a conductive layer arranged on the surface of the insulating particle. It is preferable to provide. As a result, the resin core conductive particles can sufficiently penetrate the oxide layer on the electrode surface to obtain excellent conduction reliability.

The resin core conductive particles of the first configuration example include resin core particles, a plurality of resin core particles attached to the surface of the resin core particles and serving as a core material of the protrusion, and a conductive layer covering the resin core particles and the insulating particles. With. The resin core conductive particles of the first configuration example can be obtained by a method of forming a conductive layer after attaching insulating particles to the surface of the resin core particles. As a method for attaching the insulating particles on the surface of the resin core particles, for example, the insulating particles are added to the dispersion of the resin core particles, and the insulating particles are added to the surface of the resin core particles. For example, it is possible to accumulate and adhere by using the Waals force. Examples of the method for forming the conductive layer include a method using electroless plating, a method using electroplating, and a method using physical vapor deposition. Among these, the method by electroless plating, which is easy to form a conductive layer, is preferable.

The resin core conductive particles of the second configuration example are attached to the surface of the resin core particles, a plurality of resin core particles, and cover the surfaces of the resin core particles and the insulating particles. A first conductive layer; and a second conductive layer covering the conductive layer. That is, in the second configuration example, the conductive layer of the first configuration example has a two-layer structure. When the conductive layer has a two-layer structure, the adhesion of the second conductive layer constituting the outermost shell can be improved and the conduction resistance can be reduced. The resin core conductive particles of the second configuration example can be obtained by a method of forming the second conductive layer after forming the first conductive layer after attaching the insulating particles to the surface of the resin core particle. it can. As a method for attaching the insulating particles on the surface of the resin core particles, for example, the insulating particles are added to the dispersion of the resin core particles, and the insulating particles are added to the surface of the resin core particles. For example, it is possible to accumulate and adhere by using the Waals force. Examples of the method for forming the first conductive layer and the second conductive layer include a method by electroless plating, a method by electroplating, and a method by physical vapor deposition. Among these, the method by electroless plating, which is easy to form a conductive layer, is preferable.

The resin core conductive particles of the third configuration example are attached to a plurality of resin core particles, a first conductive layer covering the surface of the resin core particles, and a surface of the first conductive layer, and serve as a core material of the protrusion. Insulating particles and a first conductive layer and a second conductive layer covering the surfaces of the insulating particles. That is, in the third configuration example, insulating particles are attached to the surface of the first conductive layer, and a second conductive layer is formed. Thereby, it is possible to prevent the insulating particles from biting into the resin core particles during pressure bonding, and the protrusions can easily break through the oxide layer on the electrode surface. The resin core conductive particles of the third configuration example can be obtained by a method in which after forming the first conductive layer on the surface of the resin core particles, the insulating particles are attached to form the second conductive layer. As a method for attaching the insulating particles on the surface of the first conductive layer, for example, the insulating particles are added to the dispersion of the resin core particles on which the first conductive layer is formed, and the first conductive layer is added. For example, insulating particles are accumulated on the surface of the layer by, for example, van der Waals force and attached. Examples of the method for forming the first conductive layer and the second conductive layer include a method by electroless plating, a method by electroplating, and a method by physical vapor deposition. Among these, the method by electroless plating, which is easy to form a conductive layer, is preferable.

Examples of the resin core particles include benzoguanamine resins, acrylic resins, styrene resins, silicone resins, polybutadiene resins, and the like, and a copolymer having a structure in which at least two kinds of repeating units based on monomers constituting these resins are combined. A polymer is mentioned. Among these, it is preferable to use a copolymer obtained by combining divinylbenzene, tetramethylolmethane tetraacrylate, and styrene.

A plurality of insulating particles are attached to the surface of the resin core particles, and serve as a core material of a protrusion for breaking through the oxide layer on the electrode surface. The insulating particles preferably have a Mohs hardness of more than 7 and 9 or more. Due to the high hardness of the insulating particles, the protrusions can break through the oxide layer on the electrode surface. Further, since the core material of the protrusion is an insulating particle, the cause of migration is reduced as compared with the case where conductive particles are used.

Examples of the insulating particles include zirconia (Mohs hardness 8-9), alumina (Mohs hardness 9), tungsten carbide (Mohs hardness 9), diamond (Mohs hardness 10), and the like. Two or more types may be used in combination. Among these, it is preferable to use alumina from the viewpoint of economy.

Further, the average particle diameter of the insulating particles is preferably 50 nm or more and 250 nm or less, more preferably 100 nm or more and 200 nm or less. Further, the number of protrusions formed on the surface of the resin core particle 20 is preferably 1 to 500, more preferably 30 to 200. By using the insulating particles 20 having such an average particle diameter, a predetermined number of protrusions are formed on the surface of the resin core particle 20, so that the protrusions break through the oxide on the electrode surface, and the connection resistance between the electrodes is effectively reduced. Can be lowered.

The conductive layer covers the resin core particles and insulating particles, and has protrusions that are raised by a plurality of insulating particles. The conductive layer is preferably nickel or a nickel alloy. Examples of the nickel alloy include Ni—WB, Ni—WP, Ni—W, Ni—B, and Ni—P. Among these, it is preferable to use Ni—WB, which has a low resistance.

Further, the thickness of the conductive layer is preferably 50 nm or more and 250 nm or less, and more preferably 80 nm or more and 150 nm or less. If the thickness of the conductive layer 30 is too small, it will be difficult to function as conductive particles, and if the thickness is too large, the height of the protrusion will be lost.

The average particle diameter of the resin core conductive particles may be 1 to 30 μm, and preferably 2 to 10 μm. In this specification, the average particle diameter means a particle diameter (D50) at an integrated value of 50% in a particle size distribution obtained by a laser diffraction / scattering method. Further, it may be obtained by measuring with an image type particle size distribution measuring apparatus (for example, FPIA-3000 (Malvern)) at N = 1000 or more.

[Insulating adhesive]
The film-forming resin corresponds to, for example, a high-molecular weight resin having an average molecular weight of 10,000 or more, and preferably has an average molecular weight of about 10,000 to 80,000 from the viewpoint of film formation. Examples of the film-forming resin include various resins such as phenoxy resin, polyester resin, polyurethane resin, polyester urethane resin, acrylic resin, polyimide resin, and butyral resin. These may be used alone or in combination of two or more. May be used. Among these, it is preferable to use a phenoxy resin from the viewpoints of film formation state, connection reliability, and the like.

The epoxy resin forms a three-dimensional network structure and imparts good heat resistance and adhesiveness, and it is preferable to use a solid epoxy resin and a liquid epoxy resin in combination. Here, the solid epoxy resin means an epoxy resin that is solid at room temperature. The liquid epoxy resin means an epoxy resin that is liquid at room temperature. The normal temperature means a temperature range of 5 to 35 ° C. defined by JIS Z 8703.

The solid epoxy resin is not particularly limited as long as it is compatible with a liquid epoxy resin and is solid at room temperature. Bisphenol A type epoxy resin, bisphenol F type epoxy resin, polyfunctional type epoxy resin, dicyclopentadiene type epoxy resin , Novolak phenol type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, and the like. Among these, one kind can be used alone, or two or more kinds can be used in combination. Among these, it is preferable to use a bisphenol A type epoxy resin. As a specific example that can be obtained on the market, there is a trade name “YD-014” of Nippon Steel & Sumikin Chemical Co., Ltd.

The liquid epoxy resin is not particularly limited as long as it is liquid at normal temperature, and examples thereof include bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolac phenol type epoxy resin, naphthalene type epoxy resin, and the like. Can be used alone or in combination of two or more. In particular, it is preferable to use a bisphenol A type epoxy resin from the viewpoint of film tackiness and flexibility. As a specific example available on the market, a trade name “EP828” of Mitsubishi Chemical Corporation may be mentioned.

As the anionic polymerization initiator, a commonly used known curing agent can be used. For example, organic acid dihydrazide, dicyandiamide, amine compound, polyamidoamine compound, cyanate ester compound, phenol resin, acid anhydride, carboxylic acid, tertiary amine compound, imidazole, Lewis acid, Bronsted acid salt, polymercaptan curing agent , Urea resin, melamine resin, isocyanate compound, block isocyanate compound, and the like. Among these, one kind can be used alone, or two or more kinds can be used in combination. Among these, it is preferable to use a microcapsule type latent curing agent having an imidazole-modified product as a core and a surface thereof coated with polyurethane. As a specific example that can be obtained on the market, there can be mentioned a trade name “Novacure 3941HP” of Asahi Kasei E-Materials Co., Ltd.

Further, as the insulating adhesive, a stress relaxation agent, a silane coupling agent, an inorganic filler, or the like may be blended as necessary. Examples of the stress relaxation agent include a hydrogenated styrene-butadiene block copolymer and a hydrogenated styrene-isoprene block copolymer. Examples of the silane coupling agent include epoxy, methacryloxy, amino, vinyl, mercapto sulfide, and ureido. Examples of the inorganic filler include silica, talc, titanium oxide, calcium carbonate, magnesium oxide and the like.

Also, the dispersion method of the resin core conductive particles in the insulating adhesive may be kneaded by mixing with the insulating adhesive before coating, or the insulating adhesive formed into a film by using a mold, etc. The conductive particles may be individually separated from the agent. In this case, the conductive particles may be regularly arranged. When the conductive particles are regularly arranged, it is preferable to have a repeating unit in the longitudinal direction of the film.

According to such a conductive material, the resin core conductive particles can break through the oxide layer even under pressure bonding under a low pressure condition because the compression recovery rate of the resin core conductive particles and the compression hardness K value at 20% compression are large. Thus, high connection reliability can be obtained.

<2. Manufacturing method of connection body>
The connection body manufacturing method according to the present embodiment includes an insulating adhesive, and a resin core conductive material having a compression recovery rate of 20% or more and a compression hardness K value at 20% compression of 4000 N / mm ² or more. An arrangement step of arranging the first electronic component and the second electronic component via a conductive material containing particles, and a second electronic component is crimped to the first electronic component by a crimping tool; A curing step of curing the material. Here, when the conductive material is not a film body, the conductive material may be applied in a film shape, or a conductive material may be provided at a pinpoint at a connection point.

In addition, the connection body according to the present embodiment includes a first electronic component, a second electronic component, and an adhesive film in which the first electronic component and the second electronic component are bonded to each other. The conductive material containing the insulating adhesive and the resin core conductive particles having a compression recovery rate of 20% or more and a compression hardness K value at 20% compression of 4000 N / mm ² or more is cured. Become. Here, even when the conductive material is not a film body, the conductive material is layered (film-like) by pressure bonding.

According to the present embodiment, the resin core conductive particles can break through the oxide layer even in the pressure bonding under the low pressure condition, and the high connection reliability can be obtained.

Hereinafter, a method for producing a connection body using the above-described thermosetting anisotropic conductive film will be described. FIG. 1 is a cross-sectional view schematically showing a connection body manufacturing method according to the present embodiment. FIG. 1 (A) shows an arrangement step (S1), and FIG. 1 (B) shows a curing step ( S2). In addition, since an anisotropic conductive film is the same as that of the above-mentioned, description is abbreviate | omitted here.

[Arrangement Step (S1)]
As shown in FIG. 1A, in the arranging step (S1), the anisotropic conductive film 20 is arranged on the first electronic component 10.

The first electronic component 10 includes a first terminal row 11, and an oxide layer is formed on the first terminal row 11. The oxide layer functions as a protective layer that prevents corrosion of the wiring, and examples thereof include TiO ₂ , SnO ₂ , and SiO ₂ .

The first electronic component 10 is not particularly limited and can be appropriately selected depending on the purpose. Examples of the first electronic component 10 include LCD (Liquid Crystal Display) panels, flat panel display (FPD) applications such as organic EL (OLED), transparent substrates for touch panel applications, printed wiring boards (PWB), and the like. It is done. The material of the printed wiring board is not particularly limited, and for example, glass epoxy such as FR-4 base material, plastic such as thermoplastic resin, ceramic, or the like can be used. In particular, when the first electronic component 10 is a low elasticity plastic substrate such as a PET (PolyEthylene Terephthalate) substrate, the effect of deformation of the base material is reduced and the resistance is reduced without increasing the pressure during crimping. Is very effective. The elastic modulus of the plastic substrate is determined in consideration of factors such as the flexibility required for the connection body and the relationship between the flexibility and the connection strength with an electronic component such as the drive circuit element 3 described later. The pressure is set to 2000 MPa to 4100 MPa. The transparent substrate is not particularly limited as long as it has high transparency, and examples thereof include a glass substrate and a plastic substrate. From the viewpoint of heat resistance, a ceramic substrate is preferably used.

Since the anisotropic conductive film 20 is the same as the anisotropic conductive film described above, detailed description thereof is omitted here. The thickness of the anisotropic conductive film 20 is not particularly limited because it can be appropriately adjusted depending on the object to be connected, but in order to facilitate handling, the lower limit is preferably 10 μm or more, and more preferably 15 μm or more. The upper limit is preferably 60 μm or less, and more preferably 50 μm or less, from the viewpoint of preventing protrusion when a wound body is used. Alternatively, a two-layer anisotropic conductive film composed of a conductive particle-containing layer and a conductive particle non-containing layer may be used (a multilayer of three or more layers may be used). The thickness of the above-mentioned anisotropic conductive film 20 indicates the total thickness in the case of a multilayer.

[Curing step (S2)]
As shown in FIG. 1B, in the curing step (S2), the second electronic component 30 is disposed on the anisotropic conductive film 20, and the second electronic component 30 is moved to the first by the thermocompression bonding tool 40. The electronic component 10 is thermocompression bonded.

The second electronic component 30 includes a second terminal row 31 that faces the first terminal row 11. The 2nd electronic component 30 does not have a restriction | limiting in particular, According to the objective, it can select suitably. Examples of the second electronic component 30 include an IC (Integrated Circuit), a flexible substrate (FPC: Flexible Printed Circuit), a tape carrier package (TCP) substrate, and a COF (Chip On Film) in which an IC is mounted on an FPC. It is done.

In the curing step (S2), the pressure tool 40 is used as an example to press at a pressure of 40 MPa to 150 MPa, preferably a pressure of 50 MPa to 130 MPa, and a low pressure of 50 MPa to 80 MPa. In the curing step (S2), pressing is performed using the crimping tool 40, preferably at a temperature of 250 ° C. or lower, more preferably at a temperature of 230 ° C. or lower, and even more preferably at a temperature of 220 ° C. or lower. Thereby, the resin is melted by the heat of the crimping tool 40, the second electronic component is sufficiently pushed by the crimping tool 40, and the resin is thermoset while the resin core conductive particles 21 are sandwiched between the terminals. Excellent electrical conductivity can be obtained. Incidentally, 40 MPa to 150 MPa means 40 MPa or more and 150 MPa or less. The same is true for other notations.

In the curing step (S2), a cushioning material may be used between the crimping tool 40 and the second electronic component 30. As the buffer material, polytetrafluoroethylene (PTFE), silicon rubber, or the like can be used.

According to such a connection body manufacturing method, since the compression recovery rate of the resin core conductive particles 21 and the compression hardness K value at the time of 20% compression are large, the resin core conductive particles are oxide layers even under pressure bonding under low pressure conditions. It is possible to break through and high connection reliability can be obtained.
<3. Example>

Hereinafter, examples of the present technology will be described. In this example, an anisotropic conductive film was prepared as an embodiment of the anisotropic conductive adhesive, and a connected body was prepared. Then, the initial conduction resistance of the connection body and the conduction resistance after the reliability test were measured. Note that the present technology is not limited to these examples.

[Preparation of anisotropic conductive film]
An anisotropic conductive film having a two-layer structure in which a conductive particle-containing layer containing resin core conductive particles shown in Table 1 and a conductive particle non-containing layer were laminated was prepared. First, 20 parts by mass of phenoxy resin (YP50, Nippon Steel Chemical Co., Ltd.), 30 parts by mass of liquid epoxy resin (EP828, Mitsubishi Chemical Co., Ltd.), solid epoxy resin (YD-014, Nippon Steel Chemical Co., Ltd.) ) 10 parts by mass, 30 parts by mass of a microcapsule-type latent curing agent (Novacure 3941H, Asahi Kasei E-Materials Co., Ltd.) and resin core conductive particles were blended to obtain a conductive particle-containing layer having a thickness of 8 μm. The resin core conductive particles were adjusted and blended so that the number density was about 50,000 / mm ² after the film was dried. The number density was measured and determined by observing 10 μm or more of a 100 μm × 100 μm region with a metal microscope.

Next, 20 parts by mass of phenoxy resin (YP50, Nippon Steel Chemical Co., Ltd.), 30 parts by mass of liquid epoxy resin (EP828, Mitsubishi Chemical Corporation), solid epoxy resin (YD-014, Nippon Steel Chemical Co., Ltd.) )) 10 parts by mass and 30 parts by mass of a microcapsule type latent curing agent (Novacure 3941H, Asahi Kasei E-Materials Co., Ltd.) were obtained to obtain a conductive particle-free layer having a thickness of 6 μm.

Then, the conductive particle-containing layer and the conductive particle non-containing layer were bonded together to obtain a two-layer anisotropic conductive film having a thickness of 14 μm.

[Production of connected body]
The connected body was manufactured by the following method and evaluated as follows. As a glass substrate, a Ti / Al wiring board having an average thickness of 0.3 mm on which a Ti / Al film was patterned was used. An IC chip (1.8 × 20 mm, t (thickness) = 0.5 mm, Au-plated bump 30 μm × 85 μm, h (height) = 9 μm) was used as an electronic component.

An anisotropic conductive film was slit to a predetermined width and attached to a Ti / Al wiring board. After temporarily fixing the IC chip thereon, using a heat tool coated with tetrafluoroethylene having an average thickness of 50 μm as a buffer material, temperature 220 ° C., pressure 130 MPa, time 5 sec pressure bonding condition 1, temperature 220 ° C., pressure Crimping was performed under pressure bonding condition 2 of 80 MPa, time 5 seconds, temperature 220 ° C., pressure 50 MPa, pressure time 3 of time 5 seconds, and a connected body was completed.

[Measurement of conduction resistance]
About the connection state of an IC chip and a Ti / Al wiring board, the conduction resistance ((ohm)) after an initial stage and a reliability test was measured using the digital multimeter. For the measurement of the conduction resistance value, a digital multimeter was connected to the wiring of the flexible wiring board connected to the bump of the bare chip, and the conduction resistance value was measured by a so-called four-terminal method with a voltage measurement of 50V. The reliability test was performed under conditions of a temperature of 85 ° C., a humidity of 85%, and a time of 500 hours.

[Evaluation of conduction resistance]
The initial conduction resistance value was evaluated as “A” for less than 1Ω, “B” for 1Ω or more and less than 2Ω, and “C” for 2Ω or more. Further, the conduction resistance value after the reliability test was evaluated as “A” when less than 2Ω, “B” when 2Ω or more and less than 5Ω, and “C” when 5Ω or more. Practically, it may be B or more, and A is preferable.

Also, the rate of increase of the conduction resistance value after the reliability test with respect to the initial conduction resistance value was calculated ((conduction resistance value after reliability test / initial conduction resistance value) × 100). The resistance value increase rate is preferably 200% or less, but if the initial conduction resistance evaluation and the conduction resistance evaluation after the reliability test are A evaluation, there is no problem even if the resistance value increase rate exceeds 200%. This is because the resistance value varies when the conduction resistance value is less than 2Ω after the reliability test. If the initial conduction resistance evaluation and the conduction resistance evaluation after the reliability test are A evaluations under different pressure conditions and the resistance value increase rate is 200% or less, it is preferable because it can withstand the influence of pressure fluctuations, and 50 MPa and If 80 MPa is satisfied, it is more preferable in that it can be used at a low pressure, and it is even more preferable if it is satisfied under all pressure conditions. In addition, if the initial conduction resistance evaluation and the conduction resistance evaluation after the reliability test are A evaluation and the resistance value increase rate is 160% or less, the fluctuation of the resistance value is stable in a narrower range. Therefore, it is more preferable. A resistance value increase rate of 160% or less indicates that even if the initial resistance value is less than 1Ω, the reliability test resistance value has a sufficient margin below 2Ω. Differences due to pressure conditions are the same as described above, and are omitted.

[Experiment 1]
As shown in Table 1, an anisotropic conductive film is produced using resin core conductive particles having an average particle size of 3 μm, a compression recovery rate of 64%, and a compression hardness K value at compression of 20% of 12600 N / mm ^2. did.

Resin core conductive particles were produced as follows. Benzoyl peroxide as a polymerization initiator was added to a solution in which the mixing ratio of divinylbenzene, styrene, and butyl methacrylate was adjusted, and the mixture was heated with uniform stirring at high speed to perform a polymerization reaction, thereby obtaining a fine particle dispersion. The fine particle dispersion was filtered and dried under reduced pressure to obtain a block body which is an aggregate of fine particles. Then, the block body was pulverized (pulverized) to obtain divinylbenzene resin particles having an average particle size of 3.0 μm.

Further, as the insulating particles, alumina (Al ₂ O ₃ ) having an average particle diameter of 150 nm was used. Moreover, nickel plating containing nickel plating solution (pH 8.5) containing nickel sulfate 0.23 mol / L, dimethylamine borane 0.25 mol / L, and sodium citrate 0.5 mol / L as a plating solution for the conductive layer. The liquid was used.

First, 10 parts by mass of resin core particles were dispersed by an ultrasonic disperser with respect to 100 parts by mass of an alkaline solution containing 5 wt% of palladium catalyst solution, and then the solution was filtered to take out resin core particles. Next, 10 parts by mass of the resin core particles were added to 100 parts by mass of a 1 wt% dimethylamine borane solution to activate the surface of the resin core particles. Then, after sufficiently washing the resin core particles with water, the dispersion was added to 500 parts by mass of distilled water and dispersed to obtain a dispersion containing resin core particles to which palladium was attached.

Next, 1 g of insulating particles was added to the dispersion over 3 minutes to obtain a slurry containing particles with insulating particles attached thereto. Then, while stirring the slurry at 60 ° C., a nickel plating solution was gradually dropped into the slurry to perform electroless nickel plating. After confirming that hydrogen foaming stopped, the particles were filtered, washed with water, substituted with alcohol, and then vacuum-dried. Conductive particles having protrusions formed of alumina and a conductive layer of Ni-B plating were obtained. Obtained. When the conductive particles were observed with a scanning electron microscope (SEM), the thickness of the conductive layer was about 100 nm.

The compression recovery rate of the resin core conductive particles and the compression hardness K value at 20% compression were obtained by adjusting the mixing ratio of divinylbenzene, styrene and butyl methacrylate when the resin core particles were produced. .

Then, using an anisotropic conductive film, pressure bonding condition 1 at temperature 220 ° C., pressure 130 MPa, time 5 sec, pressure bonding condition 2 at temperature 220 ° C., pressure 80 MPa, time 5 sec, pressure bonding condition at temperature 220 ° C., pressure 50 MPa, time 5 sec. 3 produced a connector.

[Experiment 2]
As shown in Table 1, an anisotropic conductive film is produced using resin core conductive particles having an average particle size of 3 μm, a compression recovery rate of 72%, and a compression hardness K value at compression of 20% of 10,000 N / mm ^2. A connected body was manufactured in the same manner as in Experimental Example 1 except that.

[Experiment 3]
As shown in Table 1, an anisotropic conductive film is produced using resin core conductive particles having an average particle size of 3 μm, a compression recovery rate of 67%, and a compression hardness K value at compression of 20% of 9700 N / mm ^2. A connected body was manufactured in the same manner as in Experimental Example 1 except that.

[Experimental Example 4]
As shown in Table 1, an anisotropic conductive film is produced using resin core conductive particles having an average particle size of 3 μm, a compression recovery rate of 57%, and a compression hardness K value at compression of 20% of 9000 N / mm ^2. A connected body was manufactured in the same manner as in Experimental Example 1 except that.

[Experimental Example 5]
As shown in Table 1, an anisotropic conductive film is produced using resin core conductive particles having an average particle size of 3 μm, a compression recovery rate of 65%, and a compression hardness K value at compression of 20% of 4800 N / mm ^2. A connected body was manufactured in the same manner as in Experimental Example 1 except that.

[Experimental Example 6]
As shown in Table 1, an anisotropic conductive film was prepared using resin core conductive particles having an average particle size of 3 μm, a compression recovery rate of 15%, and a compression hardness K value of 22000 N / mm ² at 20% compression. A connected body was manufactured in the same manner as in Experimental Example 1 except that.
[Experimental Example 7]
As shown in Table 1, an anisotropic conductive film is prepared using resin core conductive particles having an average particle size of 3 μm, a compression recovery rate of 25%, and a compression hardness K value of 14000 N / mm ² at 20% compression. A connected body was manufactured in the same manner as in Experimental Example 1 except that.
[Experimental Example 8]
As shown in Table 1, an anisotropic conductive film is produced using resin core conductive particles having an average particle diameter of 3 μm, a compression recovery rate of 24%, and a compression hardness K value of 11000 N / mm ² at 20% compression. A connected body was manufactured in the same manner as in Experimental Example 1 except that.
[Experimental Example 9]
As shown in Table 1, an anisotropic conductive film is prepared using resin core conductive particles having an average particle size of 3 μm, a compression recovery rate of 40%, and a compression hardness K value of 6000 N / mm ² at 20% compression. A connected body was manufactured in the same manner as in Experimental Example 1 except that.
[Experimental Example 10]
As shown in Table 1, an anisotropic conductive film was prepared using resin core conductive particles having an average particle size of 3 μm, a compression recovery rate of 37%, and a compression hardness K value at compression of 20% of 1000 N / mm ^2. A connected body was manufactured in the same manner as in Experimental Example 1 except that.

When the resin core conductive particles having a compression hardness K value at 20% compression of less than 4000 N / mm ² are used as in Experimental Example 10, the pressure is 50 MPa, the pressure is 80 MPa, and the pressure is 130 MPa. The conduction resistance evaluation after the initial stage and reliability test was C.

As in Experimental Example 6, when resin core conductive particles having a 20% compression recovery rate of less than 20% and a compression hardness K value at the time of 20% compression exceeding 20000 N / mm ² are used, Although the conduction resistance evaluation after the initial stage under the condition of 80 MPa and after the reliability test was C, the evaluation of the conduction resistance after the initial stage under the condition of 130 MPa and after the reliability test was B.

As in Experimental Example 9, when resin core conductive particles having a 20% compression recovery rate of 20% or more and a compression hardness K value at the time of 20% compression of 4000 N / mm ² or more are used, the pressure is 50 MPa. Although the initial conductive resistance evaluation at C was C, the conductive resistance evaluation after the reliability test under the conditions of a pressure of 80 MPa and a pressure of 130 MPa was B.

As in Experimental Examples 7 and 8, when resin core conductive particles having a 20% compression recovery rate of 20% or more and a compression hardness K value at the time of 20% compression of 10,000 N / mm ² or more are used, the pressure is 50 MPa. Although the initial conduction resistance evaluation under the condition of C was C, the conduction resistance evaluation after the reliability test under the condition of pressure 80 MPa was B, and the conduction resistance evaluation after the reliability test under the condition of pressure 130 MPa was A.

When using resin core conductive particles having a 20% compression recovery rate of 45% or more and a compression hardness K value at 20% compression of 4000 N / mm ² or more as in Experimental Examples 1 to 5, the pressure is 50 MPa. The conduction resistance evaluation after the reliability test under the conditions of No. 1, pressure of 80 MPa, and pressure of 130 MPa was A.

Also, from Table 1, it was found that Experimental Examples 1 to 5 and 7 to 9 under pressure conditions of 130 MPa and 80 MPa had no practical problem. In particular, Experimental Examples 1 to 5 were good and the pressure range at the time of connection was wide, which proved suitable for actual specifications. Further, since all of the pressure conditions of 130 MPa, 80 MPa, and 50 MPa were satisfactory, it was found that Experimental Examples 1 to 5 were suitable for actual specifications. In particular, in Experimental Examples 1 and 2, the conduction resistance evaluation after the initial test and after the reliability test is A under all pressure conditions, and the resistance value increase rate is stable at 160% or less. Is shown.

Since there is concern about damage to mounted parts, high connection reliability is required by crimping under low pressure conditions. The resistance values of Experimental Examples 1 to 5 after the reliability test of 50 MPa are in the relationship of “Experimental Example 1 <Experimental Example 2 <Experimental Example 3 <Experimental Example 4 <Experimental Example 5”. It was less than 7Ω. Experimental Example 1 had a resistance value of about 50% of Experimental Example 5. In Experimental Example 3, the rate of increase in the resistance value exceeds 200%. This is because the resistance value is sufficiently small, and the A evaluation is less than 2Ω (exactly less than 0.7Ω) and good. There is no problem because there is. Regarding Experimental Example 1 and Experiment 2, it was found that the rate of increase in resistance value was relatively low, and a good mounting state was obtained even at a relatively low pressure of 50 MPa.

[Particle dispersion method]
Next, using the resin core conductive particles used in Experimental Examples 1 and 2, the particle trapping property and the connection reliability due to the difference in the random or arrayed particle dispersion method were examined. For connection reliability, the initial conduction resistance of the connection body and the conduction resistance after the reliability test were measured in the same manner as described above.

[Particle trapping properties (trapping rate, particle trapping efficiency)]
The capture rate was calculated by the following formula.
[(Number of particles captured by one bump after connection (number) / area of one bump (mm ² )) / (number density of anisotropic conductive film before connection (number / mm ² ))] × 100
The number of particles captured by the bumps after connection was determined by observing and measuring the indentation observed with a metal microscope from the glass substrate side. The number of bumps whose number of traps was confirmed was 120 (N = 120), and the average value of the trapping rate was defined as the particle trapping efficiency (the fractional part was rounded off).

[Experimental Example 11]
As shown in Table 2, resin core conductive particles having an average particle diameter of 3 μm, a compression recovery rate of 64%, and a compression hardness K value at the time of 20% compression of 12600 N / mm ² were used as in Experimental Example 1. . After aligning the resin core conductive particles in a predetermined arrangement pattern on the wiring substrate, the resin core conductive particles were transferred by a film provided with an insulating resin layer to form a conductive particle-containing layer. The arrangement pattern has a shape in which conductive particles are arranged in a hexagonal lattice in the field of view of the film, and the particle number density is 28000 / mm ² . Except for this, a connection body was manufactured in the same manner as in Experimental Example 1.

[Experimental example 12]
As shown in Table 2, resin core conductive particles having an average particle diameter of 3 μm, a compression recovery rate of 72%, and a compression hardness K value at the time of 20% compression of 10,000 N / mm ² were used as in Experimental Example 2. . After aligning the resin core conductive particles in a predetermined arrangement pattern on the wiring substrate, the resin core conductive particles were transferred by a film provided with an insulating resin layer to form a conductive particle-containing layer. The arrangement pattern has a shape in which conductive particles are arranged in a hexagonal lattice in the field of view of the film, and the particle number density is 28000 / mm ² . Except for this, a connection body was manufactured in the same manner as in Experimental Example 1.

As shown in Table 2, the particle capturing efficiency when the particle dispersion method is random was 26% in Experimental Example 1 and 28% in Experimental Example 2. In addition, the particle capturing efficiency when the particle dispersion method is an array was 52% in Experimental Example 11 and 51% in Experimental Example 12. That is, it was found that the particle dispersion efficiency of the conductive particles at the time of connection is higher when the particle dispersion method is the array.

Also, from Experimental Examples 1, 2, 11, and 12, it was found that even if the particle dispersion method is a random system, connection reliability equivalent to that of the array system can be obtained. That is, it was found that the material cost can be suppressed by adopting a random system as the particle dispersion method.

DESCRIPTION OF SYMBOLS 10 1st electronic component, 11 1st terminal row | line | column, 20 anisotropic conductive adhesive film, 21 resin core conductive particle, 30 2nd electronic component, 31 2nd terminal row | line | column, 40 Crimping tool

Claims

An insulating adhesive;
A conductive material containing resin core conductive particles having a compression recovery rate of 20% or more and a compression hardness K value at 20% compression of 4000 N / mm 2 or more.
The conductive material according to claim 1, wherein the compression recovery rate of the resin core conductive particles is 45% or more, and the compression hardness K value at the time of 20% compression is 4500 N / mm 2 or more.
The conductive material according to claim 1, wherein the resin core conductive particles have a compression recovery rate of 60% or more.
The conductive material according to claim 1, wherein the resin core conductive particles have a compression hardness K value at 20% compression of 8000 N / mm 2 or more.
The conductive material according to claim 1, wherein the resin core conductive particles have a compression hardness K value at 20% compression of 20000 N / mm 2 or less.
The conductive material according to any one of claims 1 to 5, wherein the insulating adhesive contains a film-forming resin, an epoxy resin, and an anionic polymerization initiator, and the conductive material is in the form of a film.
The first through the conductive material containing the insulating adhesive and the resin core conductive particles having a compression recovery rate of 20% or more and a compression hardness K value at 20% compression of 4000 N / mm 2 or more. An arranging step of arranging the electronic component and the second electronic component;
A method of manufacturing a connection body, comprising: a step of crimping the second electronic component to the first electronic component with a crimping tool; and a curing step of curing the conductive material.
The method for manufacturing a connection body according to claim 7, wherein, in the curing step, the second electronic component is pressure-bonded to the first electronic component under a condition of 40 MPa to 150 MPa.
A first electronic component; a second electronic component; and an adhesive film in which the first electronic component and the second electronic component are bonded.
The adhesive film is made of a conductive material containing an insulating adhesive and resin core conductive particles having a compression recovery rate of 20% or more and a compression hardness K value at 20% compression of 4000 N / mm 2 or more. Hardened connection body.