CN116364328A

CN116364328A - Method for preparing conductive material and connector

Info

Publication number: CN116364328A
Application number: CN202310143827.7A
Authority: CN
Inventors: 北爪宏治; 江岛康二
Original assignee: Dexerials Corp
Current assignee: Dexerials Corp
Priority date: 2018-03-30
Filing date: 2019-03-14
Publication date: 2023-06-30
Also published as: CN117877784A; JP2019179647A; JP2022173197A; TW202001932A; JP7420883B2; KR20200110393A; CN111886657A; KR102517498B1; WO2019188372A1

Abstract

The invention provides thatAn anisotropic conductive adhesive and a method for producing a connector, which can obtain high connection reliability even under pressure bonding under low pressure conditions. The anisotropic conductive adhesive comprises an insulating adhesive and resin core conductive particles, wherein the resin core conductive particles have a 20% compression recovery rate of 20% or more and a compression hardness K value of 4000N/mm at 20% compression ² The above. Accordingly, even when the conductive particles are pressed under low pressure conditions, the oxide layer can be broken through similarly to the case of pressing under high pressure conditions, and high connection reliability can be obtained.

Description

Method for preparing conductive material and connector

The original application date of the present application is 14 at 2019, 03 and 14, the original application number is 201980019724.1 (international application number is PCT/JP 2019/010673), and the patent application of the invention name "method for producing conductive material and connector" is a divisional application.

Technical Field

The present technology relates to a conductive material for connecting a IC (Integrated Circuit) chip to a flexible wiring board, for example, and a method for producing a connector. The present application claims priority based on japanese patent application publication No. 2018-067630 filed in japan at 3 months of 2018, which is incorporated herein by reference.

Background

Conventionally, in an active matrix display device such as LCD (Liquid Crystal Display) and OLED (Organic Light Emitting Diode) displays, for example, a plurality of scanning signal lines and image signal lines intersecting each other are arranged in a matrix on an insulating substrate such as glass, and a thin film transistor (hereinafter referred to as a "TFT") is arranged at each intersection of these scanning signal lines and image signal lines.

A metal wiring film for an electrode such as a source electrode or a drain electrode of a TFT is used as IZO (Indium Zinc Oxide) instead of ITO (Indium Tin Oxide), which is costly to manufacture. The IZO wiring has a smooth surface, and an oxide layer (passivation layer) is formed on the surface. In addition, for example, in aluminum wiring, in order to prevent corrosion, tiO may be formed on the surface ₂ And a protective layer of an oxide layer. Alternatively, al/Ti wiring may be used, but it may be similar to aluminum wiring.

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

For this reason, for example, patent document 1 proposes that the compression recovery rate of the conductive particles is reduced, and that the rebound force of the conductive particles is reduced, thereby suppressing the peeling between the electrode and the circuit connecting material and obtaining good connection reliability.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open publication No. 2016-1562.

Disclosure of Invention

Problems to be solved by the invention

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 on-resistance value tends to be high. Therefore, in the method described in patent document 1, if the pressure bonding is not performed under high pressure, high connection reliability cannot be obtained, and there is a concern that damage may be caused to the mounted component.

The present technology is a technology for solving the above-described problems, and provides a conductive material which can obtain high connection reliability even under pressure bonding under low-pressure conditions, and a method for producing a connector.

Means for solving the problems

The present inventors have conducted intensive studies and as a result, have completed the present technology based on the insight that high connection reliability can be obtained even under pressure contact under low pressure conditions by using resin core conductive particles having moderately high compression recovery rate and hardness that breaks through the oxide layer.

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

The method for producing a connector according to the present technology includes: a disposing step of disposing the 1 st and 2 nd electronic components by a conductive material containing an insulating adhesive and resin core conductive particles having a compression recovery rate of 20% or more and 20% compressionCompression hardness K value at shrinkage of 4000N/mm ² The above; and a curing step of curing the conductive material while pressing the 2 nd electronic component and the 1 st electronic component by a pressing tool.

The connector according to the present technology comprises a 1 st electronic component, a 2 nd electronic component, and an adhesive film for bonding the 1 st electronic component and the 2 nd electronic component, wherein the adhesive film is formed by curing a conductive material containing an insulating adhesive and resin core conductive particles, the resin core conductive particles have a compression recovery rate of 20% or more and a compression hardness K value of 4000N/mm when compressed at 20% ² The above.

Effects of the invention

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

Drawings

Fig. 1 is a cross-sectional view schematically showing a method for producing a connector according to the present embodiment, fig. 1 (a) shows a disposing step (S1), and fig. 1 (B) shows a curing step (S2).

Detailed Description

Hereinafter, embodiments of the present technology will be described in detail in the following order with reference to the drawings.

1. Conductive material

2. Preparation method of connector

3. Examples

<1. Conductive Material >

The conductive material according to the present embodiment contains an insulating adhesive and resin core conductive particles having a compression recovery rate of 20% or more and a compression hardness K value of 4000N/mm at 20% compression ² The above. Accordingly, the oxide layer can be broken through by the resin core conductive particles even under pressure bonding under low-voltage 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. The reason for this is thought to be that by a high compression recovery rate and 20% compressionSince the wiring is crushed and deformed and the following property is improved, the oxide layer can be broken through by the high compression hardness K value at 20% compression while the contact area with the wiring is increased.

Examples of the conductive material include a film-like shape, a paste-like shape, and the like, and examples thereof include an anisotropic conductive film (ACF: anisotropic Conductive Film) and an anisotropic conductive paste (ACP: anisotropic Conductive Paste). Further, as the curing type of the conductive material, there may be mentioned: the thermosetting type, photo-curing type, photo-thermal curing type, and the like can be appropriately selected according to 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-free layer containing no resin core conductive particles are laminated will be described. As the thermosetting anisotropic conductive film, for example, there can be used: the examples of the composition include a cationic curable type, an anionic curable type, a radical curable type, and a combination of these, but only an anionic curable anisotropic conductive film will be described herein.

The anisotropic conductive film shown as a specific example includes: a conductive particle-containing layer containing resin core conductive particles, and a film-forming resin as an insulating adhesive, an epoxy resin, and an anionic polymerization initiator; and a conductive particle-free layer containing a film-forming resin as an insulating adhesive, an epoxy resin, and an anionic polymerization initiator.

[ conductive particles with resin core ]

The resin core conductive particles have a compression recovery rate of 20% or more, more preferably 45% or more, still more preferably 60% or more, and an 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 or wiring electrodes sandwiching them after connection is easily maintained well. However, according to the combination with the compression hardness K value, the connection requires high pressure.

In addition, the compression hardness K value at 20% compression of the resin core conductive particles was 4000N/mm ² Above, more preferably 8000N/mm ² The above is more preferably 10000N/mm ² The upper limit of the compression hardness K value at 20% compression is preferably below 22000N/mm ² More preferably 20000N/mm ² The following is given. If the compressive hardness K value is higher than a certain level, the resin core conductive particles tend to break through the insulating layer on the surface of the wiring electrode during connection to obtain a resistance value. However, according to the combination with the compression recovery rate, the connection requires high pressure.

The preferred combination of the compression recovery rate of the resin core conductive particles and the compression hardness K value at 20% compression is: a compression recovery rate of 20% or more and a compression hardness K value of 4000N/mm at 20% compression ² The compression recovery rate is above 45%, and the compression hardness K value at 20% compression is 4000N/mm ² The compression recovery rate is above 45%, and the compression hardness K value at 20% compression is 8000N/mm ² The compression hardness K value at 20% compression is 8000N/mm, or the compression recovery rate is 60% or more ² The above. Thus, for example, in the pressure bonding under the pressure condition of about 130MPa, the rise in the resistance value after the reliability test can be suppressed, and high connection reliability can be obtained. Pressure is required to be reduced in thickness and bending (flexibility) of electronic components. In addition, in the case of continuous connection (production of a connection body), since it is expected that the pressure is not always constant, it is desirable that a good connection state can be obtained even if the pressure condition fluctuates. For example, the catalyst may be used preferably in the range of 130MPa to 80MPa, more preferably 130MPa to 50 MPa. In particular, if the resin composition can be used in the range of 80MPa to 50MPa, the requirements for thinning and flexibility of the electronic component can be easily satisfied. This does not mean that the variation in the continuous connection is allowed within the above range, but it is described that the variation in the continuous connection is allowed to some extent if the connection is allowed within the above range. The allowable level varies depending on the connection conditions, the conditions of the electronic components, the conditions of the continuously connected devices, and the like, and thus can be appropriately adjusted.

The compression recovery rate of the resin core conductive particles can be measured as follows. The resin core conductive particles were compressed with a smooth indenter end face of a cylinder (diameter: 50 μm, made of diamond) using a micro compression tester, the displacement from the initial load (load: 0.4 mN) to the load reversal (load: 5 mN) was set to L2, and the value of L1/L2×100 (%) from the load reversal to the final load (load: 0.4 mN) was set to L1, as the compression recovery rate.

In addition, the compression hardness K value (20% K value) at 20% compression of the resin core conductive particles can be measured as follows. The resin core conductive particles were compressed with a smooth indenter end face of a cylinder (diameter 50 μm, made of diamond) using a micro compression tester under conditions of a compression speed of 2.6 mN/sec and a maximum test load of 10 gf. The load value (N) and the compression displacement (mm) at this time were measured. From the obtained measurement value, a 20% K value was obtained by the following formula. For example, "FISCHERCOPE H-100" manufactured by FISCHHER Co., ltd. Can be used as the micro compression tester. K value (N/mm) ² )＝(3/2 ^1/2 )·F·S ^-3/2 ·R ^-1/2 。

F: load value (N) at 20% compression deformation of conductive particles

S: compression displacement (mm) of conductive particles when they are deformed by 20% compression

R: radius (mm) of conductive particles

The resin core conductive particles include resin core particles and a conductive layer coating the resin core particles. The resin core conductive particle preferably includes: the resin core particle, dispose a plurality of insulating particles and forming the protruding on the surface of the resin core particle, and the conductive layer disposed on the surface of resin core particle and above-mentioned insulating particle. Thus, the resin core conductive particles break through the oxide layer on the electrode surface and are sufficiently trapped, and excellent conduction reliability can be obtained.

The resin core conductive particle according to the 1 st construction example comprises: the resin core particle, the insulating particle that adheres to the surface of the resin core particle and becomes the protruding core material, and the conductive layer that covers the resin core particle and the insulating particle. The resin core conductive particles according to configuration example 1 can be obtained by a method of forming a conductive layer by adhering insulating particles to the surface of the resin core particles. Examples of the method for attaching the insulating particles to the surface of the resin core particle include: the insulating particles are added to the dispersion of the resin core particles, and the insulating particles are attached to the surfaces of the resin core particles by, for example, van der waals forces. Further, examples of a method for forming the conductive layer include: a method using electroless (electroless) plating, a method using electroplating, a method using physical vapor deposition, and the like. Among these, a method using electroless plating is preferred in which the formation of the conductive layer is relatively easy.

The resin core conductive particle according to the configuration example 2 includes: the resin core particle, the insulating particle that adheres to the surface of the resin core particle and becomes the protruding core material, the 1 st conductive layer that coats the surface of the resin core particle and the insulating particle, and the 2 nd conductive layer that coats the conductive layer. That is, the 2 nd structural example is a structure in which the conductive layer of the 1 st structural example has a double-layer structure. By forming the conductive layer in a double-layer structure, the adhesion of the 2 nd conductive layer constituting the outermost case can be improved, and on-resistance can be reduced. The resin core conductive particle according to the structure example 2 can be obtained by a method in which insulating particles are attached to the surface of the resin core particle, and then the 1 st conductive layer is formed, and then the 2 nd conductive layer is formed. Examples of the method for attaching the insulating particles to the surface of the resin core particle include: the insulating particles are added to the dispersion of the resin core particles, and the insulating particles are attached to the surfaces of the resin core particles by, for example, van der waals forces. The method for forming the 1 st conductive layer and the 2 nd conductive layer includes, for example: a method using electroless plating, a method using electroplating, a method using physical vapor deposition, and the like. Among these, a method using electroless plating is preferred in which the formation of the conductive layer is relatively easy.

The resin core conductive particle according to the 3 rd configuration example comprises: the resin core particle, the 1 st conductive layer coating the surface of the resin core particle, the insulating particle which is formed by attaching a plurality of core materials which are protruded on the surface of the 1 st conductive layer, and the 2 nd conductive layer coating the surfaces of the 1 st conductive layer and the insulating particle. That is, the 3 rd configuration example is a configuration in which insulating particles are attached to the surface of the 1 st conductive layer, and further the 2 nd conductive layer is formed. This prevents the insulating particles from being trapped in the resin core particles during the press-bonding, and the protrusions easily break through the oxide layer on the electrode surface. The resin core conductive particle according to the 3 rd configuration example can be obtained by a method of forming the 1 st conductive layer on the surface of the resin core particle, then attaching insulating particles, and forming the 2 nd conductive layer. Examples of the method for attaching the insulating particles to the surface of the 1 st conductive layer include: insulating particles are added to the dispersion of the resin core particles on which the 1 st conductive layer is formed, and the insulating particles are attached to the surface of the 1 st conductive layer by, for example, van der Waals forces. The method for forming the 1 st conductive layer and the 2 nd conductive layer includes, for example: a method using electroless plating, a method using electroplating, a method using physical vapor deposition, and the like. Among these, a method using electroless plating is preferred in which the formation of the conductive layer is relatively easy.

The resin core particles include: benzoguanamine resins, acrylic resins, styrene resins, silicone resins, polybutadiene resins, and the like, and further, examples thereof include: a copolymer having a structure in which at least 2 or more of the repeating units based on the monomers constituting these resins are combined. Among these, a copolymer obtained by combining divinylbenzene, tetramethylolmethane tetraacrylate and styrene is preferably used.

The insulating particles are adhered to the surface of the resin core particles in a plurality of numbers and serve as core materials for the protrusions that break through the oxide layer on the electrode surface. The mohs hardness of the insulating particles is more than 7, preferably 9 or more. Since the insulating particles have high hardness, the protrusions can break through the oxide layer on the electrode surface. Further, since the core material of the protrusions is an insulating particle, migration is less likely to occur than when conductive particles are used.

The insulating particles include: zirconium oxide (mohs hardness of 8 to 9), aluminum oxide (mohs hardness of 9), tungsten carbide (mohs hardness of 9), diamond (mohs hardness of 10) and the like may be used alone or in combination of 2 or more. Among these, alumina is preferably used from the viewpoint of economy.

The average particle diameter of the insulating particles is preferably 50nm to 250nm, more preferably 100nm to 200 nm. The number of projections 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 and forming a predetermined number of protrusions on the surface of the resin core particles 20, the protrusions can break through the oxide on the electrode surface, and the connection resistance between the electrodes can be effectively reduced.

The conductive layer covers the resin core particles and the insulating particles and has protrusions formed by a plurality of the insulating particles. The conductive layer is preferably nickel or a nickel alloy. The nickel alloy includes: ni-W-B, ni-W-P, ni-W, ni-B, ni-P, and the like. Among these, ni-W-B having a low resistance is preferably used.

The thickness of the conductive layer is preferably 50nm to 250nm, more preferably 80nm to 150 nm. If the thickness of the conductive layer 30 is too small, it is difficult to function as conductive particles, and if the thickness is too large, the height of the protrusions disappears.

The average particle diameter of the resin core conductive particles may be 1 to 30. Mu.m, preferably 2 to 10. Mu.m. In the present specification, the average particle diameter refers to a particle diameter (D50) having a cumulative value of 50% in a particle size distribution obtained by a laser diffraction/scattering method. Further, the particle size distribution may be obtained by measuring n=1000 or more using an image type particle size distribution measuring apparatus (for example, FPIA-3000 (Malvern)).

[ insulating adhesive ]

The film-forming resin corresponds to, for example, a high molecular weight resin having an average molecular weight of 10000 or more, and preferably has an average molecular weight of about 10000 to 80000 from the viewpoint of film-forming properties. The film-forming resin may be: various resins such as phenoxy resin, polyester resin, polyurethane resin, polyester urethane resin, acrylic resin, polyimide resin, and butyral resin may be used alone or in combination of 2 or more. Among these, phenoxy resins are preferably used from the viewpoints of film formation state, connection reliability, and the like.

The epoxy resin is a substance that forms a three-dimensional network structure and imparts excellent heat resistance and adhesion, and it is preferable to use a solid epoxy resin and a liquid epoxy resin in combination. Herein, the solid epoxy resin refers to an epoxy resin that is solid at normal temperature. The liquid epoxy resin is an epoxy resin that is liquid at ordinary temperature. The normal temperature is a temperature range of 5 to 35℃defined in JIS Z8703.

The solid epoxy resin is not particularly limited as long as it is compatible with the liquid epoxy resin and is solid at ordinary temperature, and examples thereof include: bisphenol a type epoxy resin, bisphenol F type epoxy resin, multifunctional epoxy resin, dicyclopentadiene type epoxy resin, novolak phenol type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, and the like, and 1 or 2 or more of these may be used singly or in combination. Among these, bisphenol a type epoxy resins are preferably used. As a specific example of the commercial availability, there is mentioned the trade name "YD-014" of Nippon iron and gold chemical Co., ltd.

The liquid epoxy resin is not particularly limited as long as it is liquid at ordinary temperature, and examples thereof include: bisphenol a type epoxy resin, bisphenol F type epoxy resin, novolac phenol type epoxy resin, naphthalene type epoxy resin, etc., and 1 or 2 or more of these may be used singly or in combination. In particular, bisphenol a type epoxy resin is preferably used from the viewpoints of tackiness, flexibility and the like of the film. As a specific example of the commercial availability, there is mentioned the trade name "EP828" of Mitsubishi chemical corporation.

As the anionic polymerization initiator, a conventionally used known curing agent can be used. For example, there may be mentioned: organic acid dihydrazide, dicyandiamide (dicyandiamide), amine compound, polyamidoamine compound, cyanate ester compound, phenol resin, acid anhydride, carboxylic acid, tertiary amine compound, imidazole, lewis acid, bronsted acid salt (Bronsted acid salt), polythiol (polythiourethane) based curing agent, urea resin, melamine resin, isocyanate compound, blocked isocyanate compound, etc., and one or more of these may be used alone or in combination of 2 or more. Among these, a microcapsule-type latent curing agent having an imidazole-modified product as a core and having its surface coated with polyurethane is preferably used. As a specific example of the commercially available products, there is mentioned the trade name "Novacure 3941HP" of E-Materials, inc. of Asahi Kabushiki Kaisha.

As the insulating adhesive, a stress-relaxing agent, a silane coupling agent, an inorganic filler (filler), and the like may be blended as necessary. The stress-relaxing agent includes: hydrogenated styrene-butadiene block copolymers, hydrogenated styrene-isoprene block copolymers, and the like. Further, as the silane coupling agent, there may be mentioned: epoxy, methacryloxy, amino, vinyl, mercapto/thioether, ureide (ureide) and the like. The inorganic filler may be: silica, talc, titanium oxide, calcium carbonate, magnesium oxide, and the like.

The dispersion system of the resin core conductive particles in the insulating adhesive may be mixed with the insulating adhesive before application, or the conductive particles may be separated from each other in the insulating adhesive formed into a film shape by using a die or the like. In addition, in this case, the conductive particles may be regularly arranged. In the case where 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, since the compression recovery rate of the resin core conductive particles and the compression hardness K value at 20% compression are large, the resin core conductive particles can break through the oxide layer even under pressure bonding under low pressure conditions, and high connection reliability can be obtained.

<2 > method for producing linker >

The method for producing a linker according to this embodiment comprises: a disposing step of disposing the 1 st and 2 nd electronic components by 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 of 4000N/mm at 20% compression ² The above; and a curing step of curing the conductive material while pressing the 2 nd electronic component against the 1 st electronic component by a pressing tool. Here, in the case where the conductive material is not a film body, the conductive material may be applied in a film shape, or may be accurately provided at the connection portion.

The connector according to the present embodiment includes: 1 st electronic component, 2 nd electronic partThe electronic component 1 and the electronic component 2 are bonded by an adhesive film formed by curing a conductive material containing an insulating adhesive and resin core conductive particles, wherein the resin core conductive particles have a compression recovery rate of 20% or more and a compression hardness K value of 4000N/mm when compressed by 20% ² The above. Here, even when the conductive material is not a film body, the conductive material is formed into a layer (film) by pressure bonding.

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

Hereinafter, a method for producing a connector using the thermosetting anisotropic conductive film will be described. Fig. 1 is a cross-sectional view schematically showing a method for producing a connector according to the present embodiment, fig. 1 (a) shows a disposing step (S1), and fig. 1 (B) shows a curing step (S2). Since the anisotropic conductive film is the same as described above, the explanation thereof is omitted here.

[ configuration step (S1) ]

As shown in fig. 1 (a), in the disposing step (S1), the anisotropic conductive film 20 is disposed on the 1 st electronic component 10.

The 1 st electronic component 10 includes the 1 st terminal row 11, and an oxide layer is formed on the 1 st terminal row 11. The oxide layer functions as a protective layer for preventing corrosion of wiring, and examples thereof include: tiO (titanium dioxide) ₂ 、SnO ₂ 、SiO ₂ Etc.

The 1 st electronic component 10 is not particularly limited and may be appropriately selected depending on the purpose. The 1 st electronic component 10 includes, for example: LCD (Liquid Crystal Display) panel, flat Panel Display (FPD) such as organic EL (OLED), transparent substrate such as touch panel, printed Wiring Board (PWB), and the like. The material of the printed wiring board is not particularly limited, and for example, glass epoxy resin such as FR-4 substrate, plastic such as thermoplastic resin, ceramic, or the like may be used. In particular, when the 1 st electronic component 10 is a plastic substrate having a low elastic modulus such as a PET (Poly Ethylene Terephthalate) substrate, the effect of deformation of the base material can be reduced without increasing the pressure at the time of press bonding, and thus low resistance can be achieved, which is very effective. The elastic modulus of the plastic substrate is obtained by taking into consideration the relation between flexibility and bendability required for the connector and the connection strength with the electronic components such as the driving circuit element 3 described below, but is usually 2000MPa to 4100MPa. In addition, if the transparent substrate is a substrate having high transparency, there is no particular limitation, and examples thereof include: glass substrates, plastic substrates, and the like. From the viewpoint of heat resistance, a ceramic substrate is suitably used.

Since the anisotropic conductive film 20 is similar to the anisotropic conductive film described above, a detailed description thereof is omitted here. The thickness of the anisotropic conductive film 20 is not particularly limited, and the lower limit is preferably 10 μm or more, more preferably 15 μm or more, for easy handling, since the thickness can be appropriately adjusted according to the object to be connected. The upper limit is preferably 60 μm or less, more preferably 50 μm or less, from the viewpoint of preventing exposure when the package is produced. Further, a two-layer anisotropic conductive film (3 or more layers may be used) composed of a layer containing conductive particles and a layer not containing conductive particles. In the case of a plurality of layers, the thickness of the anisotropic conductive film 20 refers to the total thickness of the whole.

[ curing Process (S2) ]

As shown in fig. 1 (B), in the curing step (S2), the 2 nd electronic component 30 is disposed on the anisotropic conductive film 20, and the 2 nd electronic component 30 and the 1 st electronic component 10 are thermally bonded by the thermal bonding tool 40.

The 2 nd electronic component 30 includes a 2 nd terminal row 31 opposed to the 1 st terminal row 11. The 2 nd electronic component 30 is not particularly limited and may be appropriately selected depending on the purpose. Examples of the 2 nd electronic component 30 include: IC (Integrated Circuit), a flexible substrate (FPC: flexible Printed Circuits), a Tape Carrier Package (TCP) substrate, COF (Chip On Film) in which an IC is mounted on the FPC, and the like.

In the curing step (S2), the pressing is performed using the press tool 40, as an example, at a pressure of 40MPa to 150MPa, preferably 50MPa to 130MPa, and more preferably 50MPa to 80MPa as a low pressure. In the curing step (S2), the pressing is performed at a temperature of preferably 250 ℃ or lower, more preferably 230 ℃ or lower, and still more preferably 220 ℃ or lower, using the press tool 40. Accordingly, the resin is melted by the heat of the press-bonding tool 40, and the 2 nd electronic component is sufficiently pressed by the press-bonding tool 40, and the resin is thermally cured in a state where the resin core conductive particles 21 are sandwiched between the terminals, so that excellent conductivity can be obtained. 40MPa to 150MPa means 40MPa to 150 MPa. The same applies to other expressions.

In the curing step (S2), a buffer material may be used between the crimping tool 40 and the 2 nd electronic component 30. As the buffer material, polytetrafluoroethylene (PTFE), silicone rubber, or the like can be used.

According to such a method for producing a connector, since the compression recovery rate of the resin core conductive particles 21 and the compression hardness K value at 20% compression are large, the resin core conductive particles can break through the oxide layer even under pressure bonding under low pressure conditions, and high connection reliability can be obtained.

<3. Example >.

Examples

Hereinafter, embodiments of the present technology will be described. In this embodiment, an anisotropic conductive film is produced as one embodiment of an anisotropic conductive adhesive, and a connection body is produced. Then, the initial on-resistance of the connector and the on-resistance after the reliability test were measured. The present technology is not limited to these examples.

[ production of Anisotropic conductive film ]

An anisotropic conductive film having a two-layer structure in which a conductive particle-containing layer containing conductive particles of a resin core and a conductive particle-free layer were laminated as shown in table 1 was produced. First, 20 parts by mass of a phenoxy resin (YP 50, new Japan Chemical Co., ltd.), 30 parts by mass of a liquid epoxy resin (EP 828, mitsubishi Chemical Co., ltd.), 10 parts by mass of a solid epoxy resin (YD-014, new Japan Chemical Co., ltd.), 30 parts by mass of a microcapsule-type latent curing agent (Novacure 3941H, asahi Chemical E-Materials Co., ltd.), and resin core conductive particles were blended to obtain a resin core-containing resin having a thickness of 8. Mu.mAnd a conductive particle layer. The resin core conductive particles had a number density of about 50000/mm after the film was dried ² Adjustments are made to blend. The number density was obtained by observing a region of 100 μm×100 μm at 10 or more arbitrary sites with a metal microscope and measuring the region.

Next, 20 parts by mass of a phenoxy resin (YP 50, new japanese iron Chemical Co., ltd.), 30 parts by mass of a liquid epoxy resin (EP 828, mitsubishi Chemical Co., ltd.), 10 parts by mass of a solid epoxy resin (YD-014, new japanese iron Chemical Co., ltd.), 30 parts by mass of a microcapsule latent curing agent (Novacure 3941H, asahi Chemical E-Materials Co., ltd.), and a conductive particle free layer having a thickness of 6 μm were blended.

Then, the conductive particle-containing layer and the conductive particle-free layer were bonded to each other to obtain an anisotropic conductive film having a double-layer structure with a thickness of 14. Mu.m.

[ production of connector ]

The linker was prepared by the following method, and evaluated as shown below. As the glass substrate, a Ti/Al wiring board having an average thickness of 0.3mm in which a Ti/Al film was patterned was used. As the electronic component, an IC chip (1.8×20mm, t (thickness) =0.5 mm), a gold-plated bump (Au-plated bump) 30 μm×85 μm, and h (height) =9 μm was used.

The anisotropic conductive film was cut to a prescribed width and stuck to a Ti/Al wiring board. After temporarily fixing the IC chip thereon, the connection body was completed by performing crimping under crimping condition 1 having a temperature of 220 ℃, a pressure of 130MPa and a time of 5sec (seconds), crimping condition 2 having a temperature of 220 ℃, a pressure of 80MPa and a time of 5sec, and crimping condition 3 having a temperature of 220 ℃, a pressure of 50MPa and a time of 5sec using a heating tool coated with tetrafluoroethylene having an average thickness of 50 μm as a buffer material.

[ measurement of on-resistance ]

For the connection state of the IC chip and the Ti/Al wiring board, the on-resistance (Ω) after initial and reliability tests was measured using a digital multimeter. The on-resistance value was measured by connecting a digital multimeter to a wiring of a flexible wiring board connected to bumps of a bare chip, measuring the on-resistance value at a voltage of 50V, and measuring the on-resistance value by a so-called 4-terminal method. The reliability test was carried out under conditions of 85℃and 85% humidity and 500hr (hours).

[ evaluation of on-resistance ]

The initial on-resistance value was evaluated as "a" for 1 Ω or more and "B" for 2 Ω or more, and "C" for 2 Ω or more. The on-resistance value after the reliability test was evaluated as "a", and the on-resistance value after the reliability test was evaluated as "B" for 2 Ω or more and less than 5 Ω, and as "C" for 5 Ω or more. In practice, B or more is preferable, and a is preferable.

Further, the rate of increase in the on-resistance value after the reliability test relative to the initial on-resistance value ((on-resistance value after the reliability test/initial on-resistance value) ×100) was calculated. The resistance value increase rate is preferably 200% or less, but if the on-resistance evaluation after the initial on-resistance evaluation and the reliability test is the a-evaluation, there is no problem even if the resistance value increase rate exceeds 200%. This is caused by the variation in resistance value when the on-resistance value is lower than 2Ω after the reliability test. If the initial on-resistance evaluation and the reliability test-after-on-resistance evaluation are the a-evaluation under different pressure conditions, and the resistance value increase rate is 200% or less, the influence of pressure fluctuation can also be tolerated, and thus it is preferable that 50MPa and 80MPa are satisfied, it is more preferable in terms of being usable under low pressure, and it is even more preferable if all pressure conditions are satisfied. Further, if the on-resistance after the initial on-resistance evaluation and the reliability test is evaluated as a-evaluation and the resistance value increase rate is 160% or less, the variation in the resistance value is stabilized in a narrower range, which is more preferable. A resistance value increase rate of 160% or less means that the reliability test resistance value is lower than 2Ω and has a sufficient margin even if the initial resistance value is slightly lower than 1Ω. The difference due to the pressure condition is the same as that described above, and therefore, omitted.

Experimental example 1

As shown in Table 1, the average particle diameter was 3. Mu.m, the compression recovery rate was 64%, and the compression hardness K value at 20% compression was 12600N/mm ² The anisotropic conductive film is produced from the resin core conductive particles.

The resin core conductive particles were produced as follows. Benzoyl peroxide was added as a polymerization initiator to a solution in which the mixing ratio of divinylbenzene, styrene and butyl methacrylate was adjusted, and the mixture was heated while stirring uniformly at a high speed to carry out a polymerization reaction, thereby obtaining a fine particle dispersion. The microparticle dispersion was filtered and dried under reduced pressure, whereby a block was obtained as an aggregate of microparticles. Then, the mass was crushed (crushed) to obtain divinylbenzene-based resin particles having an average particle diameter of 3.0. Mu.m.

Further, as the insulating particles, alumina (Al ₂ O ₃ ). As the plating solution for the conductive layer, a nickel plating solution containing the following nickel plating solution (pH 8.5) was used: the nickel plating solution contains 0.23mol/L nickel sulfate, 0.25mol/L dimethylamine borane and 0.5mol/L sodium citrate.

First, 10 parts by mass of resin core particles were dispersed in 100 parts by mass of an alkali solution containing 5wt% palladium catalyst liquid by an ultrasonic disperser, and then the solution was filtered to take out the resin core particles. Next, 10 parts by mass of resin core particles were added to 100 parts by mass of a 1wt% dimethylamine borane solution, and the surfaces of the resin core particles were activated. Then, the resin core particles were sufficiently washed with water, and then added to 500 parts by mass of distilled water to disperse the resin core particles, thereby obtaining a dispersion liquid containing the resin core particles to which palladium was attached.

Next, 1g of insulating particles was added to the dispersion over 3 minutes to obtain a slurry containing particles to which the insulating particles were attached. Then, electroless nickel plating was performed by slowly dropping a nickel plating solution into the slurry while stirring the slurry at 60 ℃. After confirming that bubbling of hydrogen was stopped, the particles were filtered, washed with water, replaced with alcohol, and vacuum-dried to obtain conductive particles having protrusions formed of alumina and a Ni-B plated conductive layer. When the conductive particles were observed by a Scanning Electron Microscope (SEM), the thickness of the conductive layer was about 100nm.

The compression recovery rate of the resin core conductive particles and the compression hardness K value at 20% compression were adjusted to obtain predetermined values by adjusting the mixing ratio of divinylbenzene, styrene, and butyl methacrylate at the time of producing the resin core particles.

Then, a connector was prepared using an anisotropic conductive film under pressure-bonding condition 1 at 220℃and 130MPa for 5sec, pressure-bonding condition 2 at 220℃and 80MPa for 5sec, and pressure-bonding condition 3 at 220℃and 50MPa for 5 sec.

Experimental example 2

As shown in Table 1, except that the average particle diameter was 3. Mu.m, the recovery rate from compression was 72%, and the K value of compression at 20% compression was 10000N/mm ² A connector was produced in the same manner as in experimental example 1, except that an anisotropic conductive film was produced from the resin core conductive particles.

Experimental example 3

As shown in Table 1, except that the average particle diameter was 3. Mu.m, the compression recovery rate was 67%, and the compression hardness K value at 20% compression was 9700N/mm ² A connector was produced in the same manner as in experimental example 1, except that an anisotropic conductive film was produced from the resin core conductive particles.

Experimental example 4

As shown in Table 1, except that the average particle diameter was 3. Mu.m, the compression recovery rate was 57%, and the compression hardness K value at 20% compression was 9000N/mm ² A connector was produced in the same manner as in experimental example 1, except that an anisotropic conductive film was produced from the resin core conductive particles.

Experimental example 5

As shown in Table 1, except that the average particle diameter was 3. Mu.m, the compression recovery rate was 65%, and the compression hardness K value at 20% compression was 4800N/mm ² A connector was produced in the same manner as in experimental example 1, except that an anisotropic conductive film was produced from the resin core conductive particles.

Experimental example 6

As shown in Table 1, the average particle diameter was 3. Mu.m, the compression recovery rate was 15%, and the compression hardness K value at 20% compression was 22000N/mm ² A connector was produced in the same manner as in experimental example 1, except that an anisotropic conductive film was produced from the resin core conductive particles.

Experimental example 7

As shown in Table 1, except that a composition having an average particle diameter of 3 μm and a compression recovery rate were usedCompression hardness K value at 25% and 20% compression is 14000N/mm ² A connector was produced in the same manner as in experimental example 1, except that an anisotropic conductive film was produced from the resin core conductive particles.

Experimental example 8

As shown in Table 1, except that a composition having an average particle diameter of 3 μm, a compression recovery rate of 24% and a compression hardness K value of 11000N/mm at 20% compression were used ² A connector was produced in the same manner as in experimental example 1, except that an anisotropic conductive film was produced from the resin core conductive particles.

Experimental example 9

As shown in Table 1, except that the average particle diameter was 3. Mu.m, the compression recovery rate was 40%, and the compression hardness K value at 20% compression was 6000N/mm ² A connector was produced in the same manner as in experimental example 1, except that an anisotropic conductive film was produced from the resin core conductive particles.

Experimental example 10

As shown in Table 1, the average particle diameter was 3. Mu.m, the compression recovery rate was 37%, and the compression hardness K value at 20% compression was 1000N/mm ² A connector was produced in the same manner as in experimental example 1, except that an anisotropic conductive film was produced from the resin core conductive particles.

TABLE 1

As shown in Experimental example 10, the compression hardness K value at 20% compression was lower than 4000N/mm ² In the case of the resin core conductive particles of (a), the on-resistance after initial and reliability tests under the conditions of 50MPa, 80MPa and 130MPa was evaluated as C.

As shown in Experimental example 6, the compression hardness K value exceeds 20000N/mm when the 20% compression recovery rate is lower than 20% and the 20% compression is used ² In the case of the resin core conductive particles of (2), the on-resistance after the initial and reliability test under the conditions of 50MPa and 80MPa was evaluated as C, but the on-resistance after the initial and reliability test under the conditions of 130MPa was evaluated as B.

As shown in Experimental example 9, the compression hardness K value at 20% compression was 4000N/mm when the 20% compression recovery rate was 20% or more ² In the case of the resin core conductive particles described above, although the initial on-resistance under the condition of the pressure of 50MPa was evaluated as C, the on-resistance after the reliability test under the conditions of the pressure of 80MPa and the pressure of 130MPa was evaluated as B.

As shown in experimental examples 7 and 8, the compression hardness K value at 20% compression was 10000N/mm when 20% compression recovery rate was 20% or more was used ² In the case of the resin core conductive particles described above, although the initial on-resistance under the condition of the pressure of 50MPa was evaluated as C, the on-resistance after the reliability test under the condition of the pressure of 80MPa was evaluated as B, and the on-resistance after the reliability test under the condition of the pressure of 130MPa was evaluated as a.

As shown in experimental examples 1 to 5, the compression hardness K value at 20% compression was 4000N/mm when the 20% compression recovery rate was 45% or more ² In the case of the above resin core conductive particles, the on-resistance after the reliability test under the conditions of 50MPa, 80MPa and 130MPa was evaluated as A.

It is also clear from Table 1 that experimental examples 1 to 5 and 7 to 9, which had pressure conditions of 130MPa and 80MPa, have no practical problem. In particular, the experimental examples 1 to 5 were satisfactory, and the pressure range at the time of connection was wide, so that it was found that the experimental examples were suitable for practical specifications. In addition, experimental examples 1 to 5 were found to be suitable for practical specifications since they were satisfactory under all pressure conditions of 130MPa, 80MPa and 50 MPa. In particular, experimental examples 1 and 2 were evaluated as a in on-resistance after initial and reliability tests under all pressure conditions, and the rate of rise of the resistance value stabilized to 160% or less, thus showing more excellent effects.

Since there is a concern about damage to the mounting member, crimping under low pressure conditions is required to obtain high connection reliability. The resistance values of examples 1 to 5 after the 50MPa reliability test were "example 1< example 2< example 3< example 4< example 5" and were lower than 0.7Ω in the highest example 5. The resistance value of experimental example 1 was about 50% of that of experimental example 5. Although the rate of increase in resistance value of experimental example 3 exceeded 200%, this is a case where the resistance value was sufficiently small, and since it was good to be lower than 2Ω (more precisely, lower than 0.7Ω) as an a-evaluation, there was no problem. Regarding experimental examples 1 and 2, the rate of rise of the resistance value was also low, and it was found that a good mounting state was obtained even at a low pressure of 50 MPa.

[ particle Dispersion System ]

Next, using the resin core conductive particles used in experimental examples 1 and 2, particle trapping properties and connection reliability due to the difference in the random or aligned particle dispersion system were studied. For connection reliability, the initial on-resistance of the connection body and the on-resistance after the reliability test were measured in the same manner as described above.

[ particle-capturing ability (capturing Rate, particle-capturing efficiency) ]

The capture rate was calculated by the following equation.

[ (number of particles captured by 1 bump after connection)/area of 1 bump (mm) ² ) (number density (number/mm) of anisotropic conductive films before connection) ² ))]×100

The number of particles captured by the bumps after connection was obtained by observing the indentations observed by a metal microscope from the glass substrate side by a metal microscope and measuring them. Note that 120 bumps were found to be the number of catches (n=120), and the average value of the catching rate was defined as the particle catching efficiency (the number of decimal points was rounded off and rounded off).

Experimental example 11

As shown in Table 2, the same average particle diameter as in Experimental example 1 was used, and the compression recovery rate was 64%, and the compression hardness K value at 20% compression was 12600N/mm ² Is provided. After the resin core conductive particles are arranged in a predetermined arrangement pattern on the wiring substrate, the resin core conductive particles are transferred by a film provided with an insulating resin layer, thereby forming a conductive particle-containing layer. The arrangement pattern was a shape in which the conductive particles were arranged in a hexagonal lattice in the film surface visual field, and the particle number density was 28000 particles/mm ² . In addition to thatA linker was prepared in the same manner as in Experimental example 1.

Experimental example 12

As shown in Table 2, the same average particle diameter as in Experimental example 2 was used, the compression recovery rate was 72%, and the compression hardness K value at 20% compression was 10000N/mm ² Is provided. After the resin core conductive particles are arranged in a predetermined arrangement pattern on the wiring substrate, the resin core conductive particles are transferred by a film provided with an insulating resin layer, thereby forming a conductive particle-containing layer. The arrangement pattern was a shape in which the conductive particles were arranged in a hexagonal lattice in the film surface visual field, and the particle number density was 28000 particles/mm ² . A linker was prepared in the same manner as in Experimental example 1.

TABLE 2

As shown in table 2, the particle capturing efficiency was 26% in experimental example 1 and 28% in experimental example 2 in the case where the particle dispersion system was random. In addition, regarding the particle capturing efficiency in the case where the particle dispersion system was arranged, experimental example 11 was 52% and experimental example 12 was 51%. That is, it is known that the particle capturing efficiency of the conductive particles at the time of connection is high when the particle dispersion system is arranged.

Further, as is clear from experimental examples 1, 2, 11, and 12, even if the particle dispersion system is a random system, connection reliability equivalent to that of an alignment system can be obtained. That is, it is known that the material cost can be suppressed by adopting a random system as the particle dispersion system.

Symbol description

10 st electronic component, 11 st terminal row, 20 anisotropic conductive adhesive film, 21 resin core conductive particles, 30 nd electronic component, 31 st terminal row, 40 crimping tool.

Claims

1. An electroconductive material comprising an insulating adhesive and resin core electroconductive particles, wherein the resin core electroconductive particles have a compression recovery rate of 20% or more and a compression hardness K value of 4000N/m at 20% compressionm ² The above.

2. The conductive material according to claim 1, wherein the resin core conductive particles have a compression recovery rate of 45% or more and a compression hardness K value of 4500N/mm at 20% compression ² The above.

3. The conductive material according to claim 1, wherein the resin core conductive particles have a compression recovery rate of 60% or more.

4. The conductive material as set forth in claim 1, wherein said resin core conductive particles have a compression hardness K value of 8000N/mm at 20% compression ² The above.

5. The conductive material according to claim 1, wherein the resin core conductive particles have a compression hardness K value of 20000N/mm at 20% compression ² The following is given.

6. 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 a film form.

7. A method for producing a linker, comprising:

a disposing step of disposing the 1 st and 2 nd electronic components by 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 of 4000N/mm at 20% compression ² The above; and

and a curing step of curing the conductive material while pressing the 2 nd electronic component and the 1 st electronic component by a pressing tool.

8. The method of producing a connector according to claim 7, wherein in the curing step, the 2 nd electronic component and the 1 st electronic component are pressure-bonded under a condition of 40MPa to 150 MPa.

9. A connection body comprising a 1 st electronic component, a 2 nd electronic component, and an adhesive film for bonding the 1 st electronic component and the 2 nd electronic component, and

the adhesive film is formed by curing a conductive material containing an insulating adhesive and resin core conductive particles, wherein the resin core conductive particles have a compression recovery rate of 20% or more and a compression hardness K value of 4000N/mm when compressed at 20% ² The above.