CN113410671A

CN113410671A - Connecting material

Info

Publication number: CN113410671A
Application number: CN202110483681.1A
Authority: CN
Inventors: 深谷达朗; 石松朋之
Original assignee: Dexerials Corp
Current assignee: Dexerials Corp
Priority date: 2015-09-18
Filing date: 2016-09-14
Publication date: 2021-09-17
Also published as: WO2017047671A1; JP2017059471A; CN107925175A; KR20180036770A; HK1251356A1; KR20230013642A; KR20200080337A

Abstract

Provided is a connecting material which can obtain a low connection resistance value. The connecting material contains conductive particles, and the minimum melt viscosity is 1 to 100000Pa · s, and the conductive particles have: the resin composition includes resin particles, a first conductive film covering the resin particles, a plurality of protruding core members having a Vickers hardness of 1500-5000 disposed on the first conductive film, and a second conductive film covering the first conductive film and the protruding core members. Thereby, while the binder between the conductive particles and the electrode is sufficiently eliminated, the pressure applied to the electrode is sufficiently obtained, and therefore, a low connection resistance value can be obtained.

Description

Connecting material

This application is a divisional application of an invention patent application entitled "connecting material" on application date 2016, 9, 14, application number 201680050992.6 (PCT/JP 2016/077197).

Technical Field

The present invention relates to a connecting material for electrically connecting circuit members to each other via conductive particles. This application claims priority based on Japanese patent application No. 2015-185238, filed on 9/18 of Japan, which is incorporated herein by reference.

Background

In recent years, low power consumption has been demanded for mobile phones and tablet personal computers. In order to suppress power consumption, the connection resistance value needs to be suppressed to be low.

Patent documents 1 and 2 describe techniques for reducing the resistance by providing protrusions on conductive particles. However, in the conductive particles described in patent document 1, since the protrusion core material is directly adhered to the base material (resin particles), the protrusion core material is buried in the base material by the pressure at the time of mounting, and the pressure applied to the electrode is reduced. Therefore, for example, in an IZO electrode having a smooth surface, it is difficult to obtain a low connection resistance value.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2012 and 134156;

patent document 2: WO 2014/054572.

Disclosure of Invention

Problems to be solved by the invention

The present invention has been made in view of such circumstances, and an object thereof is to provide a connecting material capable of obtaining a low connection resistance value.

Means for solving the problems

In order to solve the above problems, a connecting material according to the present invention contains conductive particles having a minimum melt viscosity of 1 to 100000Pa · s, the conductive particles including: the resin composition includes a resin particle, a first conductive film covering the resin particle, a plurality of protruding core materials having a Vickers hardness of 1500-5000 disposed on the first conductive film, and a second conductive film covering the first conductive film and the protruding core materials.

Further, a method for manufacturing a connection structure according to the present invention includes: a step of mounting a second circuit member on the first circuit member via a connecting material containing conductive particles, and a step of curing the connecting material by pressing and heating the second circuit member with a pressure bonding tool; the conductive particles have: the resin particle, cover the first conductive coating of the above-mentioned resin particle, a plurality of ones that dispose on the above-mentioned first metal coating and have a Vickers hardness of 1500-5000 protruding core, and cover the above-mentioned first metal layer and second conductive coating of the core of the above-mentioned protrusion, the minimum melt viscosity of the above-mentioned connecting material is 1-100000 Pa · s.

Further, a connection structure according to the present invention includes: a first circuit member, a second circuit member, and a connection cured film for connecting the first circuit member and the second circuit member, the connection cured film including conductive particles, the conductive particles including: the resin composition includes resin particles, a first conductive film covering the resin particles, a plurality of protruding core members having a Vickers hardness of 1500-5000 disposed on the first metal film, and a second conductive film covering the first metal layer and the protruding core members.

Effects of the invention

According to the present invention, the pressure applied to the electrode is sufficiently obtained while the binder between the conductive particles and the electrode is sufficiently eliminated, and therefore a low connection resistance value can be obtained.

Drawings

FIG. 1 is a sectional view schematically showing the structure of conductive particles.

Detailed Description

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

1. Connecting material

2. Method for manufacturing connection structure

3. Examples of the embodiments

<1. connecting Material >

The connecting material according to the present embodiment contains conductive particles having a minimum melt viscosity of 1 to 100000Pa · s, the conductive particles including: the resin composition includes resin particles, a first conductive film covering the resin particles, a plurality of protruding core members having a Vickers hardness of 1500-5000 disposed on the first conductive film, and a second conductive film covering the first conductive film and the protruding core members. Thereby, while the binder between the conductive particles and the electrode is sufficiently eliminated, the pressure applied to the electrode is sufficiently obtained, and therefore, a low connection resistance value can be obtained.

The shape of the connecting material is not particularly limited, and may be appropriately selected from a film shape, a paste shape, and the like according to the application. Examples of the connecting material include: an Anisotropic Conductive Film (ACF), an Anisotropic Conductive Paste (ACP), and the like. Further, examples of the curing type of the conductive material include: a thermosetting type, a photo-curing type, a photo-thermal curing type, and the like, and can be appropriately selected according to the application.

Hereinafter, a thermosetting anisotropic conductive film containing conductive particles will be described by way of example. The thermosetting type includes, for example, a cation-curable type, an anion-curable type, a radical-curable type, or a combination thereof, but here, an anion-curable anisotropic conductive film will be described.

The anion-curable anisotropic conductive film contains a film-forming resin, an epoxy resin, and an anion polymerization initiator as a binder. The amount of the conductive particles in the anisotropic conductive film is preferably 5 to 15 vol% based on the volume of the binder. Thereby, high conduction reliability can be obtained while preventing short-circuiting.

[ Binders ]

The film-forming resin corresponds to, for example, a high molecular weight resin having an average molecular weight of 10000 or more, and an average molecular weight of approximately 10000 to 80000 is preferable from the viewpoint of film-forming properties. Examples of the film-forming resin include: various resins such as phenoxy resin, polyester resin, polyurethane resin, polyester polyurethane resin, acrylic resin, polyimide resin, butyral resin, and the like may be used alone, or 2 or more of them may be used in combination. Among these, phenoxy resins are preferably used as appropriate from the viewpoint of film formation state, connection reliability, and the like. Specific examples of commercially available products include: trade name "YP-50" of Xinri Cijin chemical (trade name) and the like.

The epoxy resin is a resin which forms a three-dimensional network structure and imparts excellent heat resistance and adhesiveness, and a solid epoxy resin and a liquid epoxy resin are preferably used in combination. Here, the solid epoxy resin means an epoxy resin which is solid at normal temperature. The liquid epoxy resin means an epoxy resin that is liquid at normal temperature. The normal temperature means a temperature range of 5 to 35 ℃ as 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 room temperature, and examples thereof include: bisphenol A type epoxy resin, bisphenol F type epoxy resin, polyfunctional epoxy resin, dicyclopentadiene type epoxy resin, phenol novolac type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, these can be used alone 1, or a combination of 2 or more.

The liquid epoxy resin is not particularly limited as long as it is liquid at room 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., these can be used alone 1, or a combination of 2 or more. In particular, bisphenol a type epoxy resins are preferably used from the viewpoint of the tackiness, flexibility, and the like of the film. Specific examples of commercially available products include: trade name "EP 828" of Mitsubishi chemical corporation, and the like.

As the anionic polymerization initiator, a generally used known curing agent can be used. Examples thereof include: 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, polythiol-based curing agent, urea resin, melamine resin, isocyanate compound, blocked isocyanate compound, etc., and 1 of these may be used alone or 2 or more of them may be used in combination. Among these, microcapsule-type latent curing agents in which imidazole modified bodies are used as cores and the surfaces thereof are covered with polyurethane are preferably used. Specific examples of commercially available products include: the trade name "Novacure 3941" of Asahi chemical E-Materials (strain) and the like.

Further, a silane coupling agent, a stress relaxation agent, an inorganic filler, and the like may be blended as necessary in the binder. Examples of the silane coupling agent include: epoxy, methacryloxy, amino, vinyl, mercapto sulfide, ureide, and the like. Further, examples of the stress relaxation agent include: hydrogenated styrene-butadiene block copolymers, hydrogenated styrene-isoprene block copolymers, and the like. Further, examples of the inorganic filler include: silica, talc, titanium oxide, calcium carbonate, magnesium oxide, and the like.

The minimum melt viscosity of the anisotropic conductive film is 1 to 100000 pas, and more preferably 10 to 10000 pas. The optimization of the minimum melt viscosity depends also on the compression deformation characteristics of the conductive particles, but if the minimum melt viscosity is too high, the adhesive between the conductive particles and the electrode cannot be sufficiently removed at the time of thermocompression bonding, and therefore the connection resistance tends to be high. In particular, it is difficult to sufficiently remove the binder between the conductive particles and the electrode in thermocompression bonding of the conductive particles having the protrusions. On the other hand, if the minimum melt viscosity is too low, the weight applied during thermocompression bonding causes the anisotropic conductive film to be deformed more, and therefore, when the pressure is released, the restoring force of the anisotropic conductive film is applied as a force in the peeling direction at the interface of the connection portion or the like. Therefore, the connection resistance tends to increase immediately after thermocompression bonding, or air bubbles tend to be generated in the connection portion.

[ conductive particles ]

Fig. 1 is a schematic cross-sectional view showing the structure of conductive particles. The conductive particles are provided with: the resin core particle 10, a first conductive layer 11 covering the resin core particle 10, a plurality of protruding core materials 12 attached on the surface of the conductive layer 11, and a second conductive layer 13 covering the first conductive layer 11 and the protruding core materials 12.

Examples of the resin core particle 10 include: benzoguanamine resins, acrylic resins, styrene resins, silicone resins, polybutadiene resins, and the like, and in addition, there may be mentioned: a copolymer having a structure in which at least 2 or more kinds of repeating units based on monomers constituting these resins are combined. Among these, a copolymer of tetramethylolmethane tetraacrylate and divinylbenzene is preferably used.

The resin core particle 10 preferably has a compression recovery rate after compression under a load of 5mN of 30% or more. If the compression recovery rate is too low, the resistance value tends to increase after a reliability test (high temperature and high humidity test). This is because, by exposure to a high temperature and high humidity test, the adhesiveness of the adhesive is reduced, and the distance between the opposite terminals of the anisotropic connection is widened. If the compression recovery rate is low, the conductive particles held cannot satisfactorily follow the conductive particles, and the resistance value may increase. The compression recovery rate was measured as the relationship between the load value and the compression displacement when the load was reduced at a rate of 0.33 mN/sec, on the contrary, after the resin particles were compressed from the center to 5mN at a rate of 0.33 mN/sec. The compression recovery rate was defined as the ratio (L1/L2) of the displacement (L1) from the point of reverse load to the final load-dividing value to the displacement (L2) from the point of reverse load to the initial load value.

The average particle diameter of the resin core particle 10 is preferably 1 to 10μm, more preferably 2 to 5μAnd m is selected. If the average particle diameter of the resin core particles 10 is too small, the resistance value tends to increase after a reliability test (high temperature and high humidity test), and if the average particle diameter of the resin core particles 10 is too large, the insulation property tends to decrease. The average particle diameter of the resin core particles 10 can be measured, for example, by using a particle size distribution measuring apparatus (product name: Microtrack MT3100, manufactured by Nikkiso).

The first conductive layer 11 is preferably a metal plating layer covering the resin core particle 10. Furthermore, the Vickers hardness of the metal plating layer is preferably 300 to 1200. If the vickers hardness of the metal plating layer is too low, it is difficult to prevent the protrusion core material 12 from being buried in the resin core particle 10 at the time of mounting, and if the vickers hardness of the metal plating layer is too high, there is a possibility that the plating layer is broken. The vickers hardness HV is a value obtained by dividing the load when a pyramid-shaped indentation is pressed on a test surface by the length of the diagonal line of the indentation using a diamond rectangular pyramid indenter having a face angle of 136 °, and is calculated as follows.

HV=0.18909×(P/d2)

P: load [ N ], d: average length of diagonal of depression [ mm ]

The metal plating layer is preferably nickel or a nickel alloy (HV: 500 to 700). Examples of the nickel alloy include: Ni-W-B, Ni-W-P, Ni-W, Ni-B, Ni-P, and the like.

The film thickness of the first conductive layer 11 is preferably 5nm or more. If the film thickness of the first conductive layer 11 is less than 5nm, it becomes difficult to prevent the protrusion core material 12 from being buried in the resin core particle 10 at the time of mounting. The thickness of the plating layer can be determined by, for example, polishing the cross section of the conductive particles using a focused ion beam processing and observation apparatus (FB-2100, hitachi high tech, ltd.), observing the cross section of 20 arbitrary conductive particles using a transmission electron microscope (H-9500, hitachi high tech, ltd.), and measuring the thickness of 5 portions of the plating film for each particle to obtain an average value.

A plurality of protruding core materials 12 are attached to the surface of the first conductive layer 11 to form a protrusion 14. The Vickers hardness of the protruding core material 12 is 1500 to 5000, preferably 1800 to 3300. If the vickers hardness of the protruding core material 12 is too low, for example, in an IZO electrode having a smooth surface, the resistance value tends to increase after a reliability test (high temperature and high humidity test), and if the vickers hardness of the protruding core material 12 is too high, the first conductive layer 11 may be punctured.

The protruding core material 12 preferably contains 1 or more metal carbides, metal carbonitrides, or cermets selected from tungsten, titanium, tantalum, and boron. Specific examples thereof include: tungsten carbide (HV: 1800), tungsten carbide-titanium carbide-tantalum carbide (HV: 2400), titanium carbide (HV: 3500), titanium carbonitride (HV: 1800), boron carbide (HV: 3300), and the like. These may be used alone, or 2 or more of them may be used in combination.

The average particle diameter of the protrusion core material 12 is preferably 50nm or more and 300nm or less, and more preferably 100nm or more and 250nm or less. The number of protrusions formed on the surface of the first conductive layer 11 is preferably 50 to 200, and more preferably 100 to 200. This can effectively reduce the connection resistance between the electrodes.

The second conductive layer 13 covers the first conductive layer 11 and the protruding core 12, and a plurality of protrusions 14 are formed to protrude from the first conductive layer 11. The second conductive layer 13 is preferably palladium, nickel, or a nickel alloy. Examples of the nickel alloy include: Ni-W-B, Ni-W-P, Ni-W, Ni-B, Ni-P, and the like.

The thickness of the second conductive layer 13 is preferably 100nm to 500nm, more preferably 50nm to 200nm in total with the first conductive layer 11. When the total film thickness of the first conductive layer 11 and the second conductive layer 13 is small, the resistance value tends to be high because a sea-island structure is formed without forming a plating layer, and when the total film thickness of the first conductive layer 11 and the second conductive layer 13 is large, the conductive particle diameter tends to be large and the insulation property tends to be low.

The conductive particles having such a structure can be obtained by forming the first conductive layer 11 on the surface of the resin core particle 10, and then attaching the protrusion core material 12 to form the second conductive layer 13. Further, as a method of attaching the protruding core material 12 to the surface of the first conductive layer 12, for example, there can be mentioned: the protruding core material 12 is added to the dispersion of the resin core particle 10 having the first conductive layer 11 formed thereon, and the protruding core material 12 is gathered or attached to the surface of the first conductive layer 11 by van der waals force, for example. Examples of a method for forming the first conductive layer 11 and the second conductive layer 13 include: 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 preferable in which the conductive layer is formed easily.

< 2> method for producing connection structure

The method for manufacturing a connection structure according to the present embodiment includes: the method for manufacturing the electronic component includes a step of mounting a second circuit member on the first circuit member via a connecting material containing conductive particles, and a step of heating and pressing the second circuit member with a pressure bonding tool to cure the connecting material. Here, as described above, the conductive particles have: the resin particle, cover the first conductive coating of the resin particle, a plurality of ones that dispose on the first metal coating and have a Vickers hardness of 1500-5000 protruding core, and cover the first metal layer and second conductive coating of the protruding core, the minimum melt viscosity of the connecting material is 1-100000 Pa · s. Thereby, while the binder between the conductive particles and the electrode is sufficiently eliminated, the pressure applied to the electrode is sufficiently obtained, and therefore, a low connection resistance value can be obtained.

The first circuit member and the second circuit member are not particularly limited and may be appropriately selected according to the purpose. Examples of the first circuit member include: plastic substrates for LCD (Liquid Crystal Display) panels, Plasma Display Panels (PDP), etc., glass substrates, Printed Wiring Boards (PWB), etc. Examples of the second circuit member include: flexible Printed Circuits (FPC) such as ICs (Integrated Circuits) and COFs (Chip On films), Tape Carrier Package (TCP) boards, and the like.

The terminal of the first circuit member and the terminal of the second circuit member are pressure-bonded by a pressure-bonding tool heated to a predetermined temperature, and the second circuit member is thermally pressurized at a predetermined pressure for a predetermined time to be finally pressure-bonded. Thereby, the adhesive of the anisotropic conductive film flows and flows out from between the terminal of the first circuit member and the mounting portion of the terminal of the second circuit member, and the adhesive is cured in a state in which the conductive particles in the adhesive are pinched and collapsed between the terminal of the first circuit member and the terminal of the second circuit member.

The predetermined pressure at the time of final pressure bonding is preferably 1MPa to 150MPa from the viewpoint of preventing the wiring of the circuit member from being broken. The predetermined temperature is a temperature of the anisotropic conductive film at the time of pressure bonding, and is preferably 80 ℃ to 230 ℃. Further, irradiation with light such as UV light may be used in combination.

The pressure bonding tool is not particularly limited and may be appropriately selected according to the purpose, and may perform pressing once using a pressing member having a larger area than the pressing target, or may perform pressing a plurality of times using a pressing member having a smaller area than the pressing target. The shape of the tip of the crimping tool is not particularly limited, and may be appropriately selected according to the purpose, and examples thereof include: planar, curved, etc. When the tip shape is a curved surface, it is preferable to press the tip along the curved surface.

Further, the second circuit member may be thermocompression bonded with a buffer material interposed therebetween. By interposing the cushion material, uneven pressing can be reduced and contamination of the crimping tool can be prevented. The cushioning material may be formed of a sheet-like elastic material or a plastic material, such as teflon (trademark), silicone rubber, or the like.

According to the method of manufacturing a connection structure of the present embodiment, since the conductive particles having the hard protrusions are used, even an IZO electrode having a smooth surface, for example, can sufficiently apply pressure, and the resistance value can be reduced. Therefore, the connection structure manufactured by the method has low resistance, and power consumption can be reduced.

Examples

<3. example >

Hereinafter, examples of the present invention will be described. In this example, a protrusion core material was attached to a metal film resin particle in which the resin particle was covered with a first conductive film, and the protrusion core material was further covered with a second conductive film to prepare a conductive particle having a protrusion. Then, a connection structure was produced using an anisotropic conductive film containing conductive particles, and the on-resistance of the connection structure was evaluated. The present invention is not limited to these examples.

[ production of conductive particles ]

Covering the first conductive film:

average particle diameter 3 formed by copolymer of tetramethylolmethane tetraacrylate and divinylbenzeneμThe resin particles of m are used as a base material. The compression recovery rate of the resin particles after compression under a load of 5mN was 45%. The resin particles were subjected to alkali degreasing with an aqueous sodium hydroxide solution, acid neutralization, and sensitization with a tin dichloride solution. Then, activation with a palladium dichloride solution was performed. After filtration and washing, the base material particles were diluted with water, the plating stabilizer was added, and then a mixture of nickel sulfate, sodium hypophosphite, sodium citrate and the plating stabilizer was added to the aqueous solution by a metering pumpThe solution is combined and electroless plating is performed so as to form a nickel plating film having a predetermined thickness. Then, the mixture was stirred until the pH value was stabilized, and generation of hydrogen bubbles was confirmed to be stopped. The plating solution was filtered, and the filtrate was washed with water and then dried by a vacuum dryer at 80 ℃.

And a protrusion core material attaching step:

after dispersing the metal film resin particles by stirring with deionized water, the protrusion core material was added to the aqueous solution to obtain particles having the protrusion core material adhered to the nickel plating film. The number of protruding core materials attached to each particle was about 150.

Covering the second conductive film:

next, the particles to which the protrusion core material was attached were degreased with an alkali using an aqueous sodium hydroxide solution, neutralized with an acid, and sensitized with a tin dichloride solution. Then, activation with a palladium dichloride solution was performed. After the filtration and washing, the base particles were diluted with water, and a plating stabilizer was added, and then a mixed solution of nickel sulfate, sodium hypophosphite, sodium citrate, and a plating stabilizer was added to the aqueous solution by a metering pump, thereby performing electroless plating so as to form a nickel plating film having a predetermined thickness. Then, the mixture was stirred until the pH value was stabilized, and generation of hydrogen bubbles was confirmed to be stopped. The plating solution was filtered, and the filtrate was washed with water and then dried by a vacuum dryer at 80 ℃.

[ measurement of the thickness of the plating film ]

With respect to the thickness of the plating film, the cross sections of arbitrary 20 conductive particles were observed using a transmission electron microscope (H-9500, hitachi high tech, ltd.) by polishing the cross sections of the conductive particles using a focused ion beam processing and observation apparatus (FB-2100, hitachi high tech, ltd.), and the thickness of 5 portions of the plating film was measured for each particle to calculate the average value.

[ measurement of minimum melt viscosity of Anisotropic conductive film ]

Using a rotary rheometer (TA Instruments), at a temperature rise rate of 10 ℃/min; the force 1N at the time of measurement was constant; the minimum melt viscosity of the anisotropic conductive film was measured under the condition that the diameter of the measurement plate was 8 mm.

[ evaluation of connection resistance ]

An IZO wiring mounted body was produced. COF (COF for evaluation of Dexerials, Ltd.) and 50 were used as evaluation substratesμm pitch, Cu 8μm t-Sn plating 38μm) and IZO beta glass (ベタガラス) (IZO beta glass for evaluation by Dexerials, IZO thickness 300nm, glass thickness 0.7 mm). First, on IZO beta glass, the width of the tool was 1.5mm using a crimper, and the cushioning material was 70 mmμAn anisotropic conductive film cut to a width of 1.5mm was temporarily bonded to m-thick Teflon (trademark) under a temporary pressure condition of 80 ℃ and 1MPa for 2 seconds, and the PET film was peeled off. Then, the COF was temporarily fixed by the same crimper under temporary fixing conditions of a temperature of 80 ℃, a pressure of 0.5MPa and a time of 0.5 seconds, and finally, as a main crimp, a crimper tool having a width of 1.5mm and a cushioning material of 70 mm was usedμm-thick teflon (trademark) was pressure-bonded under pressure-bonding conditions of 190 ℃ temperature, 3MPa pressure, and 10 seconds to obtain a mounted body.

After a high temperature and high humidity test in which the mounted body was held in a constant temperature and humidity chamber at 85 ℃ and 85% RH for 500 hours, the resistance value of the mounted body was measured by a four-terminal method using a digital multimeter. In the evaluation of the connection resistance, a case where the resistance value is less than 2.0 Ω is referred to as "a" (optimum), and a case where the resistance value is 2.0 Ω or more is referred to as "C" (defective).

[ evaluation of insulation ]

A mounted body of ITO wiring was fabricated. As evaluation substrates, IC (Dexerials IC for evaluation, 1.5 mm. times.130 mm, 0.5mm thickness, gold-plated bumps, inter-bump distance 10) was carried outμm, bump height 15μm) and glass substrate (Dexerials glass substrate for evaluation, comb pattern, and inter-bump distance 10μm, glass thickness 0.5 mm). First, on a glass substrate, a press tool having a width of 1.5mm and a cushioning material of 70 mm was usedμm-thick Teflon (trademark) is cut into pieces of 1.5mm in width under temporary pressure bonding conditions of 80 ℃ and 1MPa for 2 secondsThe anisotropic conductive film of the degree was temporarily stuck, and the peeled PET film was peeled off. Then, the IC was temporarily fixed by the same crimper under temporary fixing conditions of a temperature of 80 ℃ and a pressure of 0.5MPa for 0.5 second, and finally, as a final crimp, a crimper having a tool width of 1.5mm and a cushioning material of 70 mm was usedμm-thick teflon (trademark) was pressure-bonded under pressure-bonding conditions of 190 ℃ temperature, 3MPa pressure, and 10 seconds to obtain a mounted body.

The resistance value between the adjacent convex points of the installation body is measured by a two-terminal method, and the number below 10 & lt8 & gtomega is counted as a short circuit. In the IC for evaluation, 10 sets of bump electrode patterns were formed at 8 positions, and the number of electrode patterns in which 1 or more sets of short circuits occurred in 10 sets was counted. In the evaluation of the insulation properties, the number of short-circuited electrode patterns was 0 and was denoted by "a" (optimum), the number of short-circuited electrode patterns was 2 or less and was denoted by "B" (normal), and the number of short-circuited electrode patterns was 3 or more and was denoted by "C" (defective).

< example 1>

In the production of the conductive particles, conductive particles a were produced using tungsten carbide particles (vickers hardness 1800) having an average particle diameter of 200nm as a protrusion core material. The thickness of the nickel plating film as the first conductive film of the conductive particles A was 20nm, and the thickness of the nickel plating film as the second conductive film was 100 nm. The protruding core material also includes the following materials, and a protruding core material prepared by a known technique such as PVD method or CVD method can be suitably used. The particle diameter of the protruding core material is determined by measuring N =200 or more with an electron microscope.

A thermosetting adhesive was prepared by mixing 50 parts by mass of a microcapsule-type latent curing agent (Novacure HX3941, asahi Chemicals (ltd)), 14 parts by mass of a liquid epoxy resin (EP828, mitsubishi chemical (ltd)), 35 parts by mass of a phenoxy resin (YP50, manufactured by shin-shi koku corporation), and 1 part by mass of a silane coupling agent (KBE403, shin-Etsu chemical industry (ltd)). Conductive particles A were dispersed in the thermosetting binder so that the volume ratio of the particles was 10%, and the resultant was coated on a silicon-treated release PET film to a thickness of 20 aμm, thereby preparingA sheet-like anisotropic conductive film was formed. The minimum melt viscosity of the anisotropic conductive film is 100 pas. Table 1 shows the evaluation results of the connection resistance and the insulation property.

< example 2>

Conductive particles B having the same configuration as in example 1 were produced except that tungsten carbide-titanium carbide-tantalum carbide particles (vickers hardness 2400) having an average particle diameter of 200nm were used as the protrusion core material in the production of the conductive particles, and an anisotropic conductive film was produced. Table 1 shows the evaluation results of the connection resistance and the insulation property.

< example 3>

Conductive particles C having the same configuration as in example 1 were produced except that titanium carbide particles (vickers hardness 3500) having an average particle diameter of 200nm were used as the protrusion core material in the production of the conductive particles, and an anisotropic conductive film was produced. Table 1 shows the evaluation results of the connection resistance and the insulation property.

< example 4>

Conductive particles D having the same configuration as in example 1 were produced except that cermet particles (vickers hardness 2800) having an average particle diameter of 200nm were used as the protrusion core material in the production of the conductive particles, and an anisotropic conductive film was produced. Table 1 shows the evaluation results of the connection resistance and the insulation property.

< example 5>

In the production of the conductive particles, conductive particles E having the same configuration as in example 1 were produced, except that boron carbide particles (vickers hardness 3300) having an average particle diameter of 200nm were used as the protrusion core material, and an anisotropic conductive film was produced. Table 1 shows the evaluation results of the connection resistance and the insulation property.

< comparative example 1>

In the production of the conductive particles, conductive particles F having the same configuration as in example 1 were produced, except that nickel particles (vickers hardness 500) having an average particle diameter of 200nm were used as the protrusion core material, and an anisotropic conductive film was produced. Table 1 shows the evaluation results of the connection resistance and the insulation property.

< comparative example 2>

In the production of the conductive particles, after sensitizing and activating resin particles, washing by filtration, dispersing with deionized water by stirring, and then adding a tungsten carbide particle slurry to the aqueous solution, tungsten carbide particles (vickers hardness 1800) having an average particle diameter of 200nm were attached to the resin particles as a protrusion core material, and were covered with a nickel plating film in a second conductive film covering step, thereby producing conductive particles G. The thickness of the nickel plating film as the second conductive film of the conductive particles G was 120 nm. Then, an anisotropic conductive film was produced using the conductive particles G in the same manner as in example 1. Table 1 shows the evaluation results of the connection resistance and the insulation property.

< example 6>

In the production of the conductive particles, conductive particles H were produced using tungsten carbide particles (vickers hardness 1800) having an average particle diameter of 200nm as a protrusion core material. The thickness of the nickel plating film as the first conductive film of the conductive particles H was 5nm, and the thickness of the nickel plating film as the second conductive film was 100 nm. An anisotropic conductive film was produced in the same manner as in example 1, except that the conductive particles H were used. Table 1 shows the evaluation results of the connection resistance and the insulation property.

< example 7>

In the production of the conductive particles, conductive particles I were produced using tungsten carbide particles (vickers hardness 1800) having an average particle diameter of 200nm as a protrusion core material. The thickness of the nickel plating film as the first conductive film of the conductive particles I was 100nm, and the thickness of the nickel plating film as the second conductive film was 100 nm. An anisotropic conductive film was produced in the same manner as in example 1, except that the conductive particles I were used. Table 1 shows the evaluation results of the connection resistance and the insulation property.

< example 8>

In the production of the conductive particles, conductive particles J were produced using tungsten carbide particles (vickers hardness 1800) having an average particle diameter of 200nm as a protrusion core material. The thickness of the nickel plating film as the first conductive film of the conductive particles J was 150nm, and the thickness of the nickel plating film as the second conductive film was 350 nm. An anisotropic conductive film was produced in the same manner as in example 1, except that the conductive particles J were used. Table 1 shows the evaluation results of the connection resistance and the insulation property.

< example 9>

In the production of the conductive particles, conductive particles K were produced using tungsten carbide particles (vickers hardness 1800) having an average particle diameter of 200nm as a protrusion core material. The thickness of the nickel plating film as the first conductive film of the conductive particles K was 150nm, and the thickness of the nickel plating film as the second conductive film was 500 nm. An anisotropic conductive film was produced in the same manner as in example 1, except that the conductive particles K were used. Table 1 shows the evaluation results of the connection resistance and the insulation property.

< example 10>

In the production of the conductive particles, conductive particles L were produced using tungsten carbide particles (vickers hardness 1800) having an average particle diameter of 200nm as a protrusion core material. The thickness of the nickel plating film as the first conductive film of the conductive particles L was 20nm, and the thickness of the palladium plating film as the second conductive film was 100 nm. An anisotropic conductive film was produced in the same manner as in example 1, except that the conductive particles L were used. Table 1 shows the evaluation results of the connection resistance and the insulation property.

< comparative example 3>

A thermosetting adhesive was prepared in the same manner as in example 1, and conductive particles a were dispersed therein so that the volume ratio of the particles was 10%, and the solid content concentration of the resin and the drying conditions were adjusted to prepare an anisotropic conductive film having a minimum melt viscosity of 1000000Pa · s. Table 1 shows the evaluation results of the connection resistance and the insulation property.

< example 11>

A thermosetting adhesive was prepared in the same manner as in example 1, and conductive particles a were dispersed therein so that the volume ratio of the particles was 10%, and the solid content concentration of the resin and the drying conditions were adjusted to prepare an anisotropic conductive film having a minimum melt viscosity of 100000Pa · s. Table 1 shows the evaluation results of the connection resistance and the insulation property.

< example 12>

A thermosetting adhesive was prepared in the same manner as in example 1, and conductive particles a were dispersed therein so that the volume ratio of the particles was 10%, and the solid content concentration of the resin and the drying conditions were adjusted to prepare an anisotropic conductive film having a minimum melt viscosity of 1Pa · s. Table 1 shows the evaluation results of the connection resistance and the insulation property.

< comparative example 4>

A thermosetting adhesive was prepared in the same manner as in example 1, and conductive particles a were dispersed therein so that the volume ratio of the particles was 10%, and the solid content concentration of the resin and the drying conditions were adjusted to prepare an anisotropic conductive film having a minimum melt viscosity of 0.1Pa · s. Table 1 shows the evaluation results of the connection resistance and the insulation property.

[ Table 1]

When the vickers hardness of the protrusion core material is low as in comparative example 1, the resistance value cannot be lowered. In addition, even when the protrusion core material is directly disposed on the resin particle as in comparative example 2, the resistance value cannot be lowered. In addition, even when the lowest melt viscosity of the adhesive is not within the optimum range as in comparative examples 3 and 4, the resistance value cannot be lowered.

On the other hand, as in examples 1 to 12, the resistance value can be reduced by using a connecting material containing conductive particles in which a plurality of protruding core members having high vickers hardness are arranged on a nickel plating film covering resin particles, and a binder having an optimized minimum melt viscosity. It is also found that excellent insulation properties can be obtained by setting the total film thickness of the first conductive layer and the second conductive layer to 100nm or more and 500nm or less and the film thickness of the first conductive layer to 5nm or more.

Description of the symbols

10 core particles, 11 first metal layer, 12 protruding core material, 13 second conductive layer, 14 protrusion.

Claims

1. A method for manufacturing a connection structure, comprising:

a step of mounting a second circuit member on the first circuit member via a connecting material containing conductive particles, and

a step of heating and pressing the second circuit member with a crimping tool to cure the connecting material;

the conductive particles have: a resin particle, a first conductive film covering the resin particle, a plurality of protruding core materials with the Vickers hardness of 1500-5000 arranged on the first conductive film, and a second conductive film covering the first conductive film and the protruding core materials to form a plurality of protrusions protruding from the first conductive film,

the minimum melt viscosity of the connecting material is 1 to 100000Pa · s,

wherein the first conductive film has a film thickness of 5nm or more, the total film thickness of the first conductive film and the second conductive film is 100nm or more and 500nm or less, and the average particle diameter of the protruding core material is 50nm or more and 300nm or less.

2. The method for manufacturing a connection structure according to claim 1, wherein the protruding core material is a metal carbide, a metal carbonitride or a cermet containing at least one kind selected from tungsten, titanium, tantalum and boron.

3. The method for producing a connection structure according to claim 1, wherein the total film thickness of the first conductive film and the second conductive film is 100nm or more and 200nm or less,

the first conductive coating has a film thickness of 5nm to 100 nm.

4. The method for producing a connection structure according to claim 1, wherein the first conductive film has a Vickers hardness of 300 to 1200.

5. The method of manufacturing a connection structure according to claim 1, wherein the first conductive film is plated with nickel.

6. The method for manufacturing a connection structure according to any one of claims 1 to 5, wherein the connection material is an anisotropic conductive film.

7. A connection structure, comprising: a first circuit member, a second circuit member, and a connection cured film for connecting the first circuit member and the second circuit member,

the connection cured film includes conductive particles having: a resin particle, a first conductive film covering the resin particle, a plurality of protruding core materials with the Vickers hardness of 1500-5000 arranged on the first conductive film, and a second conductive film covering the first conductive film and the protruding core materials to form a plurality of protrusions protruding from the first conductive film,

8. The connection structure according to claim 7, wherein a connection material connecting the first circuit member and the second circuit member is an anisotropic conductive film.

9. A connecting material containing conductive particles and having a minimum melt viscosity of 1 to 100000Pa · s, the conductive particles having: a resin particle, a first conductive film covering the resin particle, a plurality of protruding core materials with the Vickers hardness of 1500-5000 arranged on the first conductive film, and a second conductive film covering the first conductive film and the protruding core materials to form a plurality of protrusions protruding from the first conductive film,

10. The method of manufacturing a connection structure according to claim 9, wherein the connection material is an anisotropic conductive film.