CN116348563A - Adhesive film for circuit connection, inorganic filler-containing composition, circuit connection structure, and method for producing same - Google Patents

Abstract

The adhesive film for circuit connection of the present invention is an adhesive film containing conductive particles, the adhesive film including a region A containing an inorganic filler in a thickness direction of the film, the region A being formed of a thermosetting composition containing an inorganic filler having a particle diameter D50 of 0.5 to 1.0 μm when 50% is accumulated and a particle diameter D95 of 0.9 to 2.0 μm when 95% is accumulated in a volume-based particle size distribution.

Description

Adhesive film for circuit connection, inorganic filler-containing composition, circuit connection structure, and method for producing same

Technical Field

The present invention relates to an adhesive film for circuit connection, an inorganic filler-containing composition, a circuit connection structure, and a method for producing the same.

Background

In recent years, in the display industry, a model shift from a liquid crystal display to an organic LED (Light Emitting Diode: light emitting diode) has occurred in a module of a display unit, and accordingly, a constituent material of a panel has changed.

In a conventional liquid crystal display, a glass substrate is used as a substrate, a metal such as aluminum is used as a circuit material formed on the glass substrate, and ITO (Indium Tin Oxide) or the like is used as an electrode on a surface layer. On the other hand, in organic LEDs, there is also a glass substrate, but in order to improve the diversity of designs (curved displays, folding displays, and the like), a flexible plastic substrate such as a polyimide substrate is used as a substrate, and Ti is mainly used as a circuit material formed on the plastic substrate. Further, a flexible member such as a pressure-sensitive adhesive layer and a polyethylene terephthalate (PET) substrate is generally disposed on the lower surface of the polyimide substrate in order to impart flexibility (for example, refer to patent document 1).

In a liquid crystal display, so-called COG (chip on glass) mounting is used in which various electronic components such as driving ICs are directly mounted on a glass substrate of a display panel from the viewpoints of finer pitch, lighter weight, thinner profile, and the like. As a COG mounting method, for example, a method of thermally bonding a liquid crystal driving IC to a glass substrate via an anisotropic conductive circuit connection adhesive film in which conductive particles are dispersed in an adhesive (adhesive) to obtain a circuit connection structure is used.

Technical literature of the prior art

Patent literature

Patent document 1: japanese patent laid-open publication 2016-054288

Disclosure of Invention

Technical problem to be solved by the invention

In organic LEDs, COP (chip on plastic) mounting in which a driving IC or the like is directly mounted on a plastic substrate is also being used. However, when an excessive pressure is applied to the plastic substrate, there are cases where problems such as deformation, cracking, and disconnection of the Ti circuit provided on the plastic substrate occur as a problem associated with deformation of the plastic substrate. Therefore, in COG mounting using an adhesive film for circuit connection, a pressure of 50 to 100MPa in terms of area conversion pressure of bump electrodes of an IC chip is usually applied, but in COP mounting in an organic LED, for example, mounting based on a low pressure of 40MPa or less is preferable in order to prevent disconnection of a circuit. In addition, there is an advantage that the selectivity of the connection member and the peripheral member is improved when mounting at low pressure in COG mounting. For example, it is expected that the connection structure can be thinned by mounting on a thinned glass substrate.

However, the mounting body manufactured under such a low-pressure condition tends to have a high connection resistance between the opposing electrodes, and it is not easy to obtain sufficient conduction characteristics. Accordingly, the inventors of the present invention studied to improve the fluidity of the adhesive existing between the conductive particles and the electrode at the time of thermocompression bonding of the adhesive film. When the binder is designed to have a high flow, it is considered to be effective to prepare an inorganic filler such as a silica filler having a relatively large primary particle diameter. However, as is clear from an examination of the inventors of the present invention, if a silica filler which is generally available is blended, a problem of poor judgment of an automatic appearance inspection apparatus may occur. In order to achieve an improvement in production efficiency, it is desirable to reduce the occurrence of defective determinations. Therefore, as a result of examining the main cause of the occurrence of the problem, it is clear that an indentation (hereinafter, also referred to as a large indentation) is generated in the wiring portion of the mounting region of the circuit connection structure, which is visually significantly stronger than the indentation generated by the conductive particles.

Accordingly, an object of the present invention is to provide an adhesive film for circuit connection and an inorganic filler-containing composition suitable for the production of such circuit connection components, in which even when circuit components are connected to each other at a low pressure, conduction between opposing electrodes of a circuit connection structure can be sufficiently ensured, and occurrence of large indentations, which are a factor of failure determination by an automatic appearance inspection device, can be sufficiently suppressed. The present invention also provides a method for producing a circuit connection structure using the adhesive film for circuit connection, and a circuit connection structure.

Means for solving the technical problems

In order to solve the above problems, an aspect of the present invention provides an adhesive film for circuit connection, comprising conductive particles, the adhesive film comprising a region a containing an inorganic filler in a thickness direction of the film, the region a being formed of a thermosetting composition containing an inorganic filler having a particle diameter D50 of 0.5 to 1.0 μm when 50% is accumulated and a particle diameter D95 of 0.9 to 2.0 μm when 95% is accumulated in a volume-based particle size distribution.

According to the adhesive film for circuit connection of the above aspect, by containing the inorganic filler having the above specific particle size distribution in the above region a, it is possible to ensure high fluidity while restricting the inclusion of the inorganic filler causing large indentations in the film, and even when circuit components are connected to each other at a low pressure, it is possible to sufficiently ensure conduction between the opposing electrodes of the circuit connection structure, and to sufficiently suppress occurrence of large indentations that are a factor of failure determination by the automatic appearance inspection device.

The adhesive film for circuit connection of the above aspect may include a region S containing no conductive particles in the thickness direction of the film, and the region a may be provided in at least a part of the region S. At this time, bridging by the conductive particles between the circuit electrodes of the adherend (for example, circuit component) where the adhesive film is in contact on the side of the region a is easily prevented.

In the adhesive film for circuit connection of the above aspect, the inorganic filler may be a silica filler.

Another aspect of the present invention provides an adhesive film for circuit connection, comprising: a 1 st adhesive layer containing conductive particles, a cured product of a photocurable resin component, and a 1 st thermosetting resin component; and a 2 nd adhesive layer provided on the 1 st adhesive layer and containing a 2 nd thermosetting resin component, the 2 nd adhesive layer being formed of an inorganic filler-containing composition containing the 2 nd thermosetting resin component and an inorganic filler having a particle diameter D50 of 0.5 to 1.0 [ mu ] m when 50% is accumulated and a particle diameter D95 of 0.9 to 2.0 [ mu ] m when 95% is accumulated in a volume-based particle size distribution.

According to the adhesive film for circuit connection of the other aspect, even when the circuit members are connected to each other at a low pressure, conduction between the opposing electrodes of the circuit connection structure can be sufficiently ensured, and occurrence of large indentations, which are a factor of failure determination by the automatic appearance inspection device, can be sufficiently suppressed. Further, according to the adhesive film for circuit connection, since the flow of the conductive particles at the time of circuit connection can be suppressed by the photo-cured material, the conductive particles can be efficiently trapped on the electrode, and high connection reliability can be easily obtained.

In the adhesive film for circuit connection of the above-mentioned other aspect, the inorganic filler may be a silica filler.

The adhesive film for circuit connection of the above-described other aspect may further include a 3 rd adhesive layer which is laminated on the opposite side of the 1 st adhesive layer from the 2 nd adhesive layer and contains a 3 rd thermosetting resin component.

By providing the 3 rd adhesive layer, the adhesive film for circuit connection of the other aspect can easily secure transfer properties and characteristics in various reliability tests, and can easily improve the remaining amount of the product.

Another aspect of the present invention provides an inorganic filler-containing composition for forming an inorganic filler-containing region in a circuit-connecting member containing conductive particles and an inorganic filler, the composition containing an inorganic filler having a particle diameter D50 of 0.5 to 1.0 μm when 50% is accumulated and a particle diameter D95 of 0.9 to 2.0 μm when 95% is accumulated in a volume-based particle size distribution.

According to the inorganic filler-containing composition of the above aspect, the inorganic filler-containing region such as the region a in the above-described adhesive film for circuit connection of the aspect and the 2 nd adhesive layer in the above-described adhesive film for circuit connection of the aspect can be formed. In addition, in the inorganic filler-containing composition of the other aspect, even when a thin layer is formed by coating, coating failure is less likely to occur, and the coating yield can be improved. Further, the inorganic filler-containing layer formed from the inorganic filler-containing composition of the other aspect can sufficiently reduce appearance defects such as scratches.

In the inorganic filler-containing composition of the above-described another aspect, the inorganic filler may be a silica filler.

The inorganic filler-containing composition of the above-mentioned another aspect can further contain a thermoplastic resin.

The inorganic filler-containing composition of the above-mentioned other aspect can be used for forming an adhesive layer having a thickness of 10 μm or less.

Another aspect of the present invention provides a method for manufacturing a circuit connection structure, including: the 1 st and 2 nd circuit members are thermally press-bonded to electrically connect the 1 st and 2 nd electrodes to each other with the above-mentioned adhesive film for circuit connection interposed between the 1 st and 2 nd circuit members having the 1 st electrode.

In the method for manufacturing a circuit connection structure according to the above aspect, one of the 1 st circuit member and the 2 nd circuit member may be an IC chip, and the other may be a plastic substrate having an electrode including Ti.

Another aspect of the present invention provides a circuit connection structure, comprising: a 1 st circuit part having a 1 st electrode; a 2 nd circuit part having a 2 nd electrode; and a circuit connection part disposed between the 1 st circuit member and the 2 nd circuit member to electrically connect the 1 st electrode and the 2 nd electrode to each other, the circuit connection part including a cured product of the adhesive film for circuit connection.

In the circuit connection structure of the other aspect, one of the 1 st circuit member and the 2 nd circuit member may be an IC chip, and the other may be a plastic substrate having an electrode including Ti.

Effects of the invention

According to the present invention, it is possible to provide an adhesive film for circuit connection and an inorganic filler-containing composition suitable for the production of such circuit connection components, in which even when circuit components are connected to each other at a low pressure, conduction between opposing electrodes of a circuit connection structure can be sufficiently ensured, and occurrence of large indentations, which are a factor of failure determination by an automatic appearance inspection device, can be sufficiently suppressed. Further, according to the present invention, a method for manufacturing a circuit connection structure using the adhesive film for circuit connection and a circuit connection structure can be provided.

Drawings

Fig. 1 is a schematic cross-sectional view showing an embodiment of an adhesive film for circuit connection.

Fig. 2 is a schematic cross-sectional view showing a method for manufacturing an adhesive film for circuit connection.

Fig. 3 is a schematic cross-sectional view showing an embodiment of the circuit connection structure.

Fig. 4 is a schematic cross-sectional view showing an embodiment of a process for manufacturing a circuit connection structure.

Detailed Description

In the present specification, the numerical ranges shown in "to" are ranges including the numerical values before and after "to" as the minimum value and the maximum value, respectively. In the numerical ranges described in the present specification in stages, the upper limit value or the lower limit value of the numerical range in one stage may be replaced with the upper limit value or the lower limit value of the numerical range in another stage. In addition, within the numerical ranges described in the present specification, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the embodiment. The upper limit and the lower limit described individually can be arbitrarily combined. In the present specification, "(meth) acrylate" means at least one of an acrylate and a methacrylate corresponding to the acrylate. The same applies to "(meth) acryl", and the like. Also, "(poly)" refers to both cases where there is an "aggregate" linker word and cases where there is no "aggregate" linker word. Further, "a or B" may include either or both of a and B. In addition, 1 kind of material may be used alone or 2 or more kinds of material may be used in combination unless otherwise specified. The content of each component in the composition means the total amount of a plurality of substances present in the composition, unless otherwise specified, in the case where the plurality of substances corresponding to each component are present in the composition.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings as necessary. However, the present invention is not limited to the following embodiments.

Adhesive film for circuit connection

The adhesive film for circuit connection of the present embodiment contains conductive particles, and includes a region a containing an inorganic filler in the thickness direction of the film, the region a being formed of a thermosetting composition containing an inorganic filler (hereinafter, sometimes referred to as "inorganic filler a") having a particle diameter D50 of 0.5 to 1.0 μm when 50% is accumulated and a particle diameter D95 of 0.9 to 2.0 μm when 95% is accumulated in a volume-based particle size distribution. The thermosetting composition forming region a can comprise a polymerizable compound and a thermal polymerization initiator.

The adhesive film for circuit connection of the present embodiment may include a region S containing no conductive particles in the thickness direction of the film, and the region a may be provided in at least a part of the region S. The proportion of the region a in the region S may be 60% or more, 80% or more, or 100% based on the range in the thickness direction of the thin film, from the viewpoint that conduction between the opposing electrodes is easily ensured even when mounted at low pressure.

The adhesive film for circuit connection of the present embodiment may include a region P further containing a cured product of a photocurable resin component in the thickness direction of the film, and conductive particles may be dispersed in the region P.

Fig. 1 is a schematic cross-sectional view showing an embodiment of an adhesive film for circuit connection according to the present embodiment. The adhesive film 1a for circuit connection shown in fig. 1 (a) (hereinafter, may be simply referred to as "adhesive film 1 a") includes: a 1 st adhesive layer 2 containing conductive particles 4, a cured product containing a photocurable resin component, and an adhesive component 5 containing a (1 st) thermosetting resin component; and a 2 nd adhesive layer 3 provided on the 1 st adhesive layer 2 and containing a (2 nd) thermosetting resin component. In addition, the adhesive film 1b for circuit connection shown in fig. 1 (b) (hereinafter, may be simply referred to as "adhesive film 1 b"), except that the 3 rd adhesive layer containing (3 rd) thermosetting resin component is laminated on the side opposite to the 2 nd adhesive layer 3 of the 1 st adhesive layer 2, the adhesive film has the same structure as the adhesive film 1 a.

Next, with reference to fig. 1, an adhesive film for circuit connection according to the present embodiment will be described.

In the adhesive films 1a, 1b, the conductive particles 4 are dispersed in the 1 st adhesive layer 2. Therefore, the adhesive films 1a, 1b may be adhesive films for circuit connection having anisotropic conductivity (anisotropic conductive adhesive films). The adhesive films 1a, 1b may be interposed between a 1 st circuit member having a 1 st electrode and a 2 nd circuit member having a 2 nd electrode, for thermocompression bonding the 1 st and 2 nd circuit members to electrically connect the 1 st and 2 nd electrodes to each other.

< 1 st adhesive layer >

The 1 st adhesive layer 2 contains a cured product of conductive particles 4 (hereinafter, sometimes referred to as "(a) component" "), a photocurable resin component (hereinafter, sometimes referred to as" (B) component "") and a thermosetting resin component (hereinafter, sometimes referred to as "(C) component"). The 1 st adhesive layer 2 can be obtained, for example, by irradiating a composition layer formed from a composition containing the component (a), the component (B) and the component (C) with light energy, polymerizing the components contained in the component (B), and curing the component (B). The 1 st adhesive layer 2 contains a component (A), a cured product containing a component (B), and an adhesive component 5 containing a component (C). (B) The cured product of the component (B) may be a cured product obtained by completely curing the component (B), or may be a cured product obtained by partially curing the component (B). (C) The component is a component that can flow when connected to a circuit, and is, for example, an uncured curable resin component.

(A) The components are as follows: conductive particles

The component (a) is not particularly limited as long as it is a particle having conductivity, and may be a metal particle composed of a metal such as Au, ag, pd, ni, cu or solder, a conductive carbon particle composed of conductive carbon, or the like. (A) The component (c) may be coated conductive particles including a core made of non-conductive glass, ceramic, plastic (polystyrene, etc.) or the like, and a coating layer made of the metal or conductive carbon and coating the core. Among them, the component (a) preferably includes a core including metal particles or plastic made of a heat-fusible metal and coated conductive particles including metal or conductive carbon and a coating layer coating the core. Since such coated conductive particles are easily deformed by heating or pressurizing the cured product of the thermosetting resin component, the contact area between the electrode and the component (a) can be increased when the electrodes are electrically connected to each other, and the conductivity between the electrodes can be further improved.

From the viewpoint of easily exhibiting low resistance to a circuit having a Ti surface, conductive particles having palladium plating can be used as the conductive particles. In this case, palladium plating can be provided on the outermost surface of the conductive particles. Specifically, it is possible to use conductive particles in which Ni plating is performed on the surface of the plastic core and substitution plating is performed on the outermost surface with Pd, and from the viewpoint of preventing short-circuiting between conductive particles, such conductive particles may be used in which insulating fine particles are supported on the surface thereof. From the viewpoint of more easily exhibiting low resistance, in the process of plating with Ni, a ceramic core material of 100nm to 200nm is taken into plating, and then Pd plating is performed, whereby insulating fine particles can be carried as needed.

(A) The component (c) may be an insulating coated conductive particle comprising the metal particle, a conductive carbon particle, or an insulating layer containing an insulating material such as a resin and coating the surface of the particle. If the component (a) is an insulating coated conductive particle, even when the content of the component (a) is large, the insulating layer is provided on the surface of the particle, so that occurrence of short-circuiting due to contact between the components (a) can be suppressed, and the insulation between adjacent electrode circuits can be improved. (A) The component (c) may be used alone or in combination of 1 or more than 2 of the above-mentioned various conductive particles.

(A) The maximum particle size of the component needs to be smaller than the minimum spacing of the electrodes (shortest distance between adjacent electrodes). The maximum particle diameter of the component (A) may be 1.0 μm or more, 2.0 μm or more, or 2.5 μm or more from the viewpoint of excellent dispersibility and conductivity. The maximum particle diameter of the component (A) may be 20 μm or less, 10 μm or less, or 5 μm or less from the viewpoint of excellent dispersibility and electrical conductivity. In the present specification, the particle size was measured by observation using a Scanning Electron Microscope (SEM) for any 300 (pcs) of conductive particles, and the obtained maximum value was used as the maximum particle size of the component (a). In addition, in the case where the component (a) has a protrusion or the like, and the component (a) is not spherical, the particle diameter of the component (a) is the diameter of a circle circumscribed to the conductive particle in the SEM image.

The average particle diameter of the component (A) may be 1.0 μm or more, 2.0 μm or more, or 2.5 μm or more from the viewpoint of excellent dispersibility and conductivity. The average particle diameter of the component (A) may be 20 μm or less, 10 μm or less, or 5 μm or less from the viewpoint of excellent dispersibility and electrical conductivity. In the present specification, the particle size was measured for any 300 (pcs) of conductive particles by observation using a Scanning Electron Microscope (SEM), and the average value of the obtained particle sizes was taken as the average particle size.

In the 1 st adhesive layer 2, the component (a) is preferably uniformly dispersed. From which stable connection resistance can be obtainedFrom the viewpoint of (A) component in the adhesive films 1a, 1b, the particle density may be 100 pieces/mm ² Above 1000 pieces/mm ² Above 3000 pieces/mm ² Above or 5000 pieces/mm ² The above. The particle density of the component (A) in the adhesive films 1a, 1b may be 100000 pieces/mm from the viewpoint of improving the insulation between adjacent electrodes ² Below 70000 pieces/mm ² Below 50000 pieces/mm ² Below or 30000 pieces/mm ² The following is given.

The content of the component (a) may be 1 mass% or more, 5 mass% or more, or 10 mass% or more based on the total mass of the 1 st adhesive layer, from the viewpoint of further improving the electrical conductivity. From the viewpoint of easy short circuit suppression, the content of the component (a) may be 60 mass% or less, 50 mass% or less, or 40 mass% or less based on the total mass of the 1 st adhesive layer. When the content of the component (a) is within the above range, the effect of the present invention tends to be remarkably exhibited. In addition, the content of the component (a) in the composition or the composition layer (based on the total mass of the composition or the composition layer) may be the same as the above range.

(B) The components are as follows: photocurable resin component

The component (B) is not particularly limited as long as it is a resin component cured by light irradiation, but may be a resin component having radical curability from the viewpoint of further excellent connection resistance. (B) The component (c) may include, for example, a radical polymerizable compound (hereinafter, sometimes referred to as a "(B1) component") and a photo radical polymerization initiator (hereinafter, sometimes referred to as a "(B2) component"). (B) The component (B1) may be a component composed of a component (B2).

(B1) The components are as follows: radical polymerizable compound

(B1) The component (B2) is a radical-polymerized compound generated from the component (B) by irradiation with light (for example, ultraviolet light). (B1) The component (c) may be any of a monomer, or a polymer (or oligomer) obtained by polymerizing 1 or 2 or more monomers. The component (B1) may be used alone or in combination of 1 or more.

(B1) The component (a) is a compound having a radical polymerizable group which reacts with a radical. Examples of the radical polymerizable group include a (meth) acryloyl group, a vinyl group, an allyl group, a styryl group, an alkenyl group, an alkenylene group, and a maleimide group. The number of radical polymerizable groups (the number of functional groups) in the component (B1) may be 2 or more from the viewpoint of easily obtaining a desired melt viscosity after polymerization, further improving the effect of reducing the connection resistance, and further improving the connection reliability, and may be 10 or less from the viewpoint of suppressing the curing shrinkage at the time of polymerization. In order to maintain the balance between the crosslinking density and the curing shrinkage, a compound having a radical polymerizable group amount outside the above range may be used in addition to a compound having a radical polymerizable group amount within the above range.

From the viewpoint of suppressing the flow of the conductive particles, for example, the (B1) component may contain a polyfunctional (2-functional or more) (meth) acrylate. The multifunctional (2-functional or more) (meth) acrylate may be a 2-functional (meth) acrylate, and the 2-functional (meth) acrylate may be a 2-functional aromatic (meth) acrylate.

Examples of the polyfunctional (meth) acrylate include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, tetrapropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, ethoxylated polypropylene glycol di (meth) acrylate, 1, 3-butanediol di (meth) acrylate, 1, 4-butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 3-methyl-1, 5-pentanediol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, 2-butyl-2-ethyl-1, 3-propanediol di (meth) acrylate, 1, 9-nonanediol di (meth) acrylate, 1, 10-decanediol di (meth) acrylate, glycerol di (meth) acrylate, tricyclodecanedimethanol (meth) acrylate, ethoxylated 2-methyl-1, 3-propanediol (meth) acrylate, and the like aliphatic acrylates; an aromatic (meth) acrylate such as an ethoxylated bisphenol A type di (meth) acrylate, a propoxylated bisphenol A type di (meth) acrylate, an ethoxylated bisphenol F type di (meth) acrylate, a propoxylated bisphenol F type di (meth) acrylate, an ethoxylated fluorene type di (meth) acrylate, a propoxylated fluorene type di (meth) acrylate, an ethoxylated propoxylated fluorene type di (meth) acrylate, a trimethylolpropane tri (meth) acrylate, an ethoxylated trimethylolpropane tri (meth) acrylate propoxylated trimethylol propane tri (meth) acrylate, ethoxylated propoxylated trimethylol propane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, ethoxylated pentaerythritol tri (meth) acrylate, propoxylated pentaerythritol tri (meth) acrylate, ethoxylated propoxylated pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, ethoxylated pentaerythritol tetra (meth) acrylate, propoxylated pentaerythritol tetra (meth) acrylate, ethoxylated propoxylated pentaerythritol tetra (meth) acrylate, ditrimethylol propane tetraacrylate, aliphatic (meth) acrylates such as dipentaerythritol hexa (meth) acrylate; aromatic epoxy (meth) acrylates such as bisphenol type epoxy (meth) acrylate, novolak type epoxy (meth) acrylate, cresol novolak type epoxy (meth) acrylate, and the like.

From the viewpoint of both the effect of reducing the connection resistance and the suppression of particle flow, the content of the multifunctional (2-functional or more) acrylate may be, for example, 40 to 100 mass%, 50 to 100 mass%, or 60 to 100 mass% based on the total mass of the component (B1).

(B1) The component (c) may contain a monofunctional (meth) acrylate in addition to the multifunctional (2-functional or more) (meth) acrylate. Examples of the monofunctional (meth) acrylate include (meth) acrylic acid; aliphatic (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, butoxyethyl (meth) acrylate, isoamyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, heptyl (meth) acrylate, octyl heptyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, hydroxyethyl (2- (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, ethoxypolyethylene glycol (meth) acrylate, methoxypolypropylene glycol (meth) acrylate, ethoxypolypropylene glycol (meth) acrylate, mono (2- (meth) acryloyloxyethyl) succinate; aromatic (meth) acrylates such as benzyl (meth) acrylate, phenyl (meth) acrylate, o-biphenyl (meth) acrylate, naphthalene 1- (meth) acrylate, naphthalene 2- (meth) acrylate, phenoxyethyl (meth) acrylate, p-cumylphenoxyethyl (meth) acrylate, o-phenylphenoxyethyl (meth) acrylate, 1-naphthyloxyethyl (meth) acrylate, 2-naphthyloxyethyl (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, nonylphenoxypolyglycol (meth) acrylate, phenoxypolypropylene glycol (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 2-hydroxy-3- (o-phenylphenoxy) propyl (meth) acrylate, 2-hydroxy-3- (1-naphthyloxy) propyl (meth) acrylate, 2-hydroxy-3- (2-naphthyloxy) propyl (meth) acrylate; and oxetanyl group-containing (meth) acrylates such as epoxy group-containing (meth) acrylates such as glycidyl (meth) acrylate, and alicyclic epoxy group-containing (meth) acrylates such as 3, 4-epoxycyclohexylmethyl (meth) acrylate, and (3-ethyloxetan-3-yl) methyl (meth) acrylate.

The content of the monofunctional (meth) acrylate may be, for example, 0 to 60 mass%, 0 to 50 mass%, or 0 to 40 mass% based on the total mass of the component (B1).

(B) The cured product of the component (a) may have a polymerizable group that reacts in addition to the radical. The polymerizable group that reacts by a method other than the radical may be, for example, a cationic polymerizable group that reacts by a cation. Examples of the cationically polymerizable group include an epoxy group such as a glycidyl group, an alicyclic epoxy group such as a cyclohexylmethyl group, and an oxetanyl group such as an ethyloxetanylmethyl group. The cured product of the component (B) having a polymerizable group that reacts in addition to a radical can be introduced by using, for example, a (meth) acrylate having a polymerizable group that reacts in addition to a radical, such as a (meth) acrylate having an epoxy group, a (meth) acrylate having an alicyclic epoxy group, or a (meth) acrylate having an oxetanyl group, as the component (B). From the viewpoint of improving reliability, the mass ratio of the (meth) acrylate having the polymerizable group that reacts with the other than the radical to the total mass of the (B1) component (the mass (charged amount) of the (meth) acrylate having the polymerizable group that reacts with the other than the radical)/(the total mass (charged amount) of the B1) component) may be, for example, 0 to 0.7, 0 to 0.5, or 0 to 0.3.

(B1) The component (c) may contain a radical polymerizable compound in addition to the polyfunctional (2-functional or more) and the monofunctional (meth) acrylate. Examples of the other radically polymerizable compound include maleimide compounds, vinyl ether compounds, allyl compounds, styrene derivatives, acrylamide derivatives, nadic imide (Nadiimide) derivatives, and the like. The content of the other radically polymerizable compound may be, for example, 0 to 40% by mass based on the total mass of the component (B1).

(B2) The components are as follows: photo radical polymerization initiator

(B2) The component (c) is a photopolymerization initiator that generates radicals by irradiating light having a wavelength in the range of 150 to 750nm, preferably light having a wavelength in the range of 254 to 405nm, and more preferably light having a wavelength of 365nm (for example, ultraviolet light). The component (B2) may be used alone or in combination of 1 or more.

(B2) The component is decomposed by light and generates free radicals. That is, the component (B2) is a compound that generates radicals by applying light energy from the outside. (B2) The component (c) may be a compound having an oxime ester structure, a bisimidazole structure, an acridine structure, an α -aminoalkylbenzophenone structure, an aminobenzophenone structure, an N-phenylglycine structure, an acylphosphine oxide structure, a benzyldimethyl ketal structure, an α -hydroxyalkylbenzophenone structure, or the like. The component (B2) may be used alone or in combination of 1 or more. The component (B2) may be a compound having at least 1 structure selected from the group consisting of an oxime ester structure, an α -aminoalkylbenzophenone structure and an acylphosphine oxide structure, from the viewpoint of easy obtaining of a desired melt viscosity and more excellent effect of reducing the connection resistance.

Specific examples of the compound having an oxime ester structure include 1-phenyl-1, 2-butanedione-2- (o-methoxycarbonyl) oxime, 1-phenyl-1, 2-propanedione-2- (o-ethoxycarbonyl) oxime, 1-phenyl-1, 2-propanedione-2-o-benzoyloxime, 1, 3-diphenylpropanetrione-2- (o-ethoxycarbonyl) oxime, 1-phenyl-3-ethoxypropanetrione-2- (o-benzoyl) oxime, 1, 2-octanedione, 1- [4- (phenylthio) phenyl-, 2- (o-benzoyl oxime) ], ethanone, 1- [ 9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl ] -,1- (o-acetyloxime) and the like.

Specific examples of the compound having an α -aminoalkylbenzophenone structure include 2-methyl-1- [4- (methylthio) phenyl ] -2-morpholinopropane-1-one, 2-benzyl-2-dimethylamino-1-morpholinophenyl) -butanone-1 and the like.

Specific examples of the compound having an acylphosphine oxide structure include bis (2, 6-dimethoxybenzoyl) -2, 4-trimethyl-pentylphosphine oxide, bis (2, 4, 6-trimethylbenzoyl) -phenylphosphine oxide, and 2,4, 6-trimethylbenzoyl-diphenylphosphine oxide.

The content of the component (B2) may be, for example, 0.1 to 10 parts by mass, 0.3 to 7 parts by mass, or 0.5 to 5 parts by mass, relative to 100 parts by mass of the component (B1), from the viewpoint of suppressing the flow of the conductive particles.

The content of the cured product of the component (B) may be 1 mass% or more, 5 mass% or more, or 10 mass% or more based on the total mass of the 1 st adhesive layer from the viewpoint of suppressing the flow of the conductive particles. From the viewpoint of exhibiting low resistance in low-voltage mounting, the content of the cured product of the component (B) may be 50 mass% or less, 40 mass% or less, or 30 mass% or less based on the total mass of the 1 st adhesive layer. In addition, the content of the (B) component in the composition or the composition layer for forming the 1 st adhesive layer (based on the total mass of the composition or the composition layer) may be the same as the above range.

(C) The components are as follows: thermosetting resin component

(C) The component (C2) may be a component (C1) or a component (C2) that is a component of the composition. (C) The component (C) may be a component consisting of a component (C1) and a component (C2). The 1 st thermosetting resin component and the 2 nd thermosetting resin component refer to thermosetting resin components contained in the 1 st adhesive layer and the 2 nd adhesive layer, respectively. The types, combinations, and contents of the components (e.g., the (C1) component and the (C2) component) contained in the 1 st thermosetting resin component and the 2 nd thermosetting resin component may be the same or different from each other.

(C1) The components are as follows: cationically polymerizable compound

(C1) The component (C2) is a compound that is crosslinked by reacting with heat. The component (C1) is a compound having no radical polymerizable group which reacts by a radical, and the component (C1) is not included in the component (B1). The component (C1) may be a compound having 1 or more ring-opening polymerizable cyclic ether groups in the molecule, from the viewpoint of further improving the effect of reducing the connection resistance and further improving the connection reliability. The component (C1) may be used alone or in combination of 1 or more. The compound having 1 or more ring-opening polymerizable cyclic ether groups in the molecule may be, for example, at least 1 selected from the group consisting of oxetane compounds and alicyclic epoxy compounds. From the viewpoint of easily obtaining a desired melt viscosity, the (C1) component preferably contains both at least 1 oxetane compound and at least 1 alicyclic epoxy compound.

The oxetane compound as the component (C1) may be used without any particular limitation as long as it has an oxetanyl group and does not have a radical polymerizable group. Examples of commercial products of oxetane compounds include ETERNACOLL OXBP (trade name, manufactured by UBE Corporation), OXSQ, OXT-121, OXT-221, OXT-101, and OXT-212 (trade name, TOAGOSEI CO., manufactured by LTD.). These may be used alone or in combination of 1 or more.

The alicyclic epoxy compound as the component (C1) may be used without any particular limitation as long as it has an alicyclic epoxy group (for example, epoxycyclohexyl group) and does not have a radical polymerizable group. Examples of the commercially available alicyclic epoxy compounds include EHPE3150, EHPE3150CE, CELLOXIDE8010, CELLOXIDE2021P, CELLOXIDE2081 (trade name, manufactured by Daicel Corporation), and the like. These may be used alone or in combination of 1 or more.

(C2) The components are as follows: thermal cationic polymerization initiator

(C2) The component (c) is a thermal polymerization initiator which initiates polymerization by heating to generate an acid or the like. (C2) The component may be a salt compound composed of a cation and an anion. Examples of the component (C2) include a component having BF ₄ ^- 、BR ₄ ^- (R represents a phenyl group substituted with 2 or more fluorine atoms or 2 or more trifluoromethyl groups), PF ₆ ^- 、SbF ₆ ^- 、AsF ₆ ^- Sulfonium salts, phosphonium salts, ammonium salts, diazonium salts, iodonium salts, anilinium salts, and the like of the plasma anions. These may be used alone or in combination of 1 or more.

From the viewpoint of storage stability, the (C2) component may be, for example, a BF which is an anion containing boron as a constituent element ₄ ^- Or BR ₄ ^- (R represents a phenyl group substituted with 2 or more fluorine atoms or 2 or more trifluoromethyl groups). The anion containing boron as a constituent element may be BR ₄ ^- More specifically, it may be a tetrakis (pentafluorophenyl) borate.

The onium salt as the (C2) component may be, for example, an anilinium salt because of its resistance to a substance that may cause curing resistance to cationic curing. Examples of the anilinium salt compound include N, N-dialkylanilinium salts such as N, N-dimethylanilinium salts and N, N-diethylanilinium salts.

(C2) The component may be an anilinium salt having an anion containing boron as a constituent element. As a commercial product of such a salt compound, CXC-1821 (trade name, manufactured by King Industries, inc.) and the like are exemplified.

From the viewpoint of securing the formability and curability of the adhesive film used to form the 1 st adhesive layer, the content of the (C2) component may be, for example, 0.1 to 25 parts by mass, 1 to 20 parts by mass, 3 to 18 parts by mass, or 5 to 15 parts by mass, relative to 100 parts by mass of the (C1) component.

From the viewpoint of ensuring the curability of the adhesive film used to form the 1 st adhesive layer, the content of the component (C) may be 5 mass% or more, 10 mass% or more, 15 mass% or more, or 20 mass% or more based on the total mass of the 1 st adhesive layer. From the viewpoint of ensuring the formability of the adhesive film used to form the 1 st adhesive layer, the content of the component (C) may be 70 mass% or less, 60 mass% or less, 50 mass% or less, or 40 mass% or less, based on the total mass of the 1 st adhesive layer. In addition, the content of the (C) component in the composition or the composition layer for forming the 1 st adhesive layer (based on the total mass of the composition or the composition layer) may be the same as the above range.

[ other Components ]

The 1 st adhesive layer 2 may further contain other components in addition to the component (a), the cured product of the component (B), and the component (C). Examples of the other components include thermoplastic resins (hereinafter, sometimes referred to as "(D") components), coupling agents (hereinafter, sometimes referred to as "(E") components), and fillers (hereinafter, sometimes referred to as "(F") components).

As the component (D), a resin functioning as a film forming component can be used, and examples thereof include phenoxy resin, polyester resin, polyamide resin, polyurethane resin, polyester urethane resin, acrylate rubber, epoxy resin (solid at 25 ℃), and the like. These may be used alone or in combination of 1 or more. The composition layer (further, the 1 st adhesive layer 2) can be easily formed from the composition containing the component (a), the component (B) and the component (C) further containing the component (D). Wherein the component (D) may be, for example, a phenoxy resin.

The weight average molecular weight (Mw) of the component (D) may be, for example, 5000 to 200000, 10000 to 100000, 20000 to 80000, or 40000 to 60000 from the viewpoint of resin exclusivity at the time of mounting. The Mw is a value measured by Gel Permeation Chromatography (GPC) and converted using a calibration curve based on standard polystyrene.

The content of the component (D) may be 1 mass% or more, 5 mass% or more, 10 mass% or more, or 20 mass% or more, or 70 mass% or less, 60 mass% or less, 50 mass% or less, or 40 mass% or less, based on the total mass of the 1 st adhesive layer. In addition, the content of the (D) component in the composition or the composition layer for forming the 1 st adhesive layer (based on the total mass of the composition or the composition layer) may be the same as the above range.

Examples of the component (E) include silane coupling agents having an organic functional group such as a (meth) acryloyl group, a mercapto group, an amino group, an imidazole group, and an epoxy group, silane compounds such as tetraalkoxysilane, tetraalkoxy titanate derivatives, and polydialkyl titanate derivatives. These may be used alone or in combination of 1 or more. The adhesive layer 2 of the 1 st step contains the component (E), whereby the adhesion (adhesive) can be further improved. The component (E) may be, for example, a silane coupling agent. The content of the component (E) may be 0.1 to 10 mass% based on the total mass of the 1 st adhesive layer. In addition, the content of the (E) component in the composition or the composition layer for forming the 1 st adhesive layer (based on the total mass of the composition or the composition layer) may be the same as the above range.

As the component (F), for example, a nonconductive filler (for example, nonconductive particles) is given. (F) The component (c) may be any of an inorganic filler and an organic filler. Examples of the inorganic filler include metal oxide particles such as silica particles, alumina particles, silica-alumina particles, titania particles, and zirconia particles; inorganic particles such as metal nitride particles. Examples of the organic filler include organic particles such as silicone particles, methacrylate/butadiene/styrene particles, acrylic/silicone particles, polyamide particles, and polyimide particles. These may be used alone or in combination of 1 or more. The component (F) can be appropriately formulated within a range that does not impair the effects of the present invention, and the content of the component (F) (the total mass of the composition or the composition layer) in the composition or the composition layer for forming the 1 st adhesive layer can be appropriately set within a range that does not impair the effects of the present invention.

[ other additives ]

The 1 st adhesive layer 2 may further contain other additives such as a softener, an accelerator, a deterioration inhibitor, a colorant, a flame retardant, and a thixotropic agent. The content of the other additive may be, for example, 0.1 to 10 mass% based on the total mass of the 1 st adhesive layer. In addition, the content of the composition for forming the 1 st adhesive layer or other additives in the composition layer (based on the total mass of the composition or composition layer) may be the same as the above range.

The thickness d1 of the 1 st adhesive layer 2 may be 0.1 times or more, 0.2 times or more, or 0.3 times or more the average particle diameter of the conductive particles 4, from the viewpoint that the conductive particles 4 are easily trapped between the opposing electrodes, and the connection resistance can be further reduced. The thickness d1 of the 1 st adhesive layer 2 may be 0.8 times or less or 0.7 times or less the average particle diameter of the conductive particles 4, from the viewpoint that the conductive particles are more likely to collapse when sandwiched between the opposing electrodes during thermocompression bonding, and the connection resistance can be further reduced. From these viewpoints, the thickness d1 of the 1 st adhesive layer 2 may be 0.1 to 0.8 times, 0.2 to 0.8 times, or 0.3 to 0.7 times the average particle diameter of the conductive particles 4. The thickness d1 of the 1 st adhesive layer 2 is the thickness of the 1 st adhesive layer located at the divided portions of the adjacent conductive particles 4, 4.

When the thickness d1 of the 1 st adhesive layer 2 and the average particle diameter of the conductive particles 4 satisfy the above-described relationship, for example, as shown in fig. 1, a part of the conductive particles 4 in the 1 st adhesive layer 2 may protrude from the 1 st adhesive layer 2 to the 2 nd adhesive layer 3 side. At this time, the boundary S between the 1 st adhesive layer 2 and the 2 nd adhesive layer 3 is located at the separated portion of the adjacent conductive particles 4, 4. Since the boundary S exists on the conductive particles along the surface of the conductive particles, the conductive particles 4 in the 1 st adhesive layer 2 do not protrude from the 1 st adhesive layer 2 to the 2 nd adhesive layer 3 side, and the above relationship can be satisfied. The conductive particles 4 are not exposed on the surface 2a of the 1 st adhesive layer 2 on the opposite side from the 2 nd adhesive layer 3 side, and the surface 2a on the opposite side may be a flat surface.

The relation between the thickness d1 of the 1 st adhesive layer 2 and the maximum particle diameter of the conductive particles 4 may be the same as described above. For example, the thickness d1 of the 1 st adhesive layer 2 may be 0.1 to 0.8 times, 0.2 to 0.8 times, or 0.3 to 0.7 times the maximum particle diameter of the conductive particles 4.

The thickness d1 of the 1 st adhesive layer 2 may be, for example, 5.0 μm or less. The thickness d1 of the 1 st adhesive layer 2 may be 4.5 μm or less or 4.0 μm or less. The 1 st adhesive layer 2 has a thickness d1 of 5.0 μm or less, whereby conductive particles at the time of circuit connection can be further efficiently captured. The thickness d1 of the 1 st adhesive layer 2 may be, for example, 0.1 μm or more, 0.5 μm or more, or 0.7 μm or more. The thickness d1 of the 1 st adhesive layer 2 can be obtained by, for example, sandwiching an adhesive film between 2 pieces of glass (thickness: about 1 mm), casting a resin composition composed of 100g of bisphenol a type epoxy resin (trade name: JER, manufactured by Mitsubishi Chemical Corporation) and 10g of diethylenetriamine (Tokyo Chemical Industry co., manufactured by ltd.) and then subjecting the resultant product to cross-sectional polishing using a grinder, and measuring the resultant product using a scanning electron microscope (SEM, trade name: SE-8010,Hitachi High-Tech Science Corporation). As shown in fig. 1, when a part of the conductive particles 4 is exposed from the surface of the 1 st adhesive layer 2 (for example, protrudes toward the 2 nd adhesive layer 3), the distance from the surface 2a of the 1 st adhesive layer 2 on the opposite side to the 2 nd adhesive layer 3 side to the boundary S between the 1 st adhesive layer 2 and the 2 nd adhesive layer 3 located at the separated portion of the adjacent conductive particles 4, 4 (the distance denoted by d1 in fig. 1) is the thickness of the 1 st adhesive layer 2, and the exposed part of the conductive particles 4 is not included in the thickness of the 1 st adhesive layer 2. The length of the exposed portion of the conductive particle 4 may be, for example, 0.1 μm or more or 5.0 μm or less.

< 2 nd adhesive layer >

The 2 nd adhesive layer 3 may contain a component (C) and a component (F). The (C1) component and the (C2) component used in the (C) component (i.e., the (2) th thermosetting resin component) in the 2 nd adhesive layer 3 are the same as the (C1) component and the (C2) component used in the (C) component (i.e., the (1) th thermosetting resin component) in the 1 st adhesive layer 2, and thus detailed description thereof is omitted herein. The 2 nd thermosetting resin component may be the same as or different from the 1 st thermosetting resin component.

From the viewpoint of maintaining reliability, the content of the component (C) may be 5 mass% or more, 10 mass% or more, 15 mass% or more, or 20 mass% or more based on the total mass of the 2 nd adhesive layer. From the viewpoint of preventing resin bleeding failure on the reel as one of the supply methods, the content of the component (C) may be 70 mass% or less, 60 mass% or less, 50 mass% or less, or 40 mass% or less based on the total mass of the 2 nd adhesive layer.

The 2 nd adhesive layer 3 may contain an inorganic filler as the component (F). From the standpoint of sufficiently ensuring conduction between the opposing electrodes of the circuit connection structure and sufficiently suppressing occurrence of large indentations that are the main cause of failure determination by the automatic appearance inspection device even when the circuit members are connected to each other at a low pressure, the 2 nd adhesive layer 3 can be formed of a thermosetting composition containing an inorganic filler having a particle diameter D50 of 0.5 to 1.0 μm when 50% is accumulated and a particle diameter D95 of 0.9 to 2.0 μm when 95% is accumulated in a volume-based particle size distribution.

As the inorganic filler, silica fillers such as silica microparticles can be used from the viewpoint of improving reliability. The content of silica in the silica filler may be 99 mass% or more, or may be 100 mass% or more based on the total amount of the silica filler.

As for the inorganic filler having the above-mentioned volume-based particle size distribution, for example, it can be obtained by the following method: an inorganic filler containing inorganic particles having a primary particle diameter of 0.3 to 0.7 μm or an inorganic filler having a volume average particle diameter of 1.0 to 2.0 μm is prepared, and inorganic particles having a particle diameter of 2.0 μm or more are removed by a known classification method such as air classification, filtration using filter paper or capsule filter, or the like.

The D50 of the inorganic filler may be 0.5 to 1.0. Mu.m, 0.6 to 0.9. Mu.m, or 0.7 to 0.8. Mu.m, from the viewpoint of ensuring fluidity easily. Further, from the viewpoint of suppressing the occurrence of large indentations, the inorganic filler may have a D95 of 0.9 to 2.0. Mu.m, 1.0 to 1.8. Mu.m, or 1.1 to 1.6. Mu.m.

The content of the inorganic filler in the 2 nd adhesive layer 3 or the thermosetting composition forming the 2 nd adhesive layer 3 may be 10 to 70% by mass, may be 20 to 60% by mass, or may be 30 to 50% by mass based on the total mass of the 2 nd adhesive layer or the thermosetting composition from the viewpoint of ensuring conduction between the opposed electrodes even when mounted under low pressure and ensuring film properties as a tape-like product.

The 2 nd adhesive layer 3 may further contain other components and other additives in the 1 st adhesive layer 2. The preferred mode of other components and other additives is the same as that of the 1 st adhesive layer 2.

The content of the component (D) may be 1 mass% or more, 5 mass% or more, or 10 mass% or more, or 80 mass% or less, 60 mass% or less, or 40 mass% or less, based on the total mass of the 2 nd adhesive layer.

The content of the component (E) may be 0.1 to 10 mass% based on the total mass of the 2 nd adhesive layer.

The content of the other additive may be, for example, 0.1 to 10 mass% based on the total mass of the 2 nd adhesive layer.

The thickness d2 of the 2 nd adhesive layer 3 may be appropriately set according to the height of the electrode of the bonded circuit member, etc. The thickness d2 of the 2 nd adhesive layer 3 may be 5 μm or more or 7 μm or more, or 15 μm or less or 11 μm or less from the viewpoint of sufficiently filling the space between the electrodes to seal the electrodes and obtaining more excellent connection reliability. The thickness d2 of the 2 nd adhesive layer 3 can be obtained by, for example, the same method as the method for measuring the thickness d1 of the 1 st adhesive layer 2. When a part of the conductive particles 4 is exposed from the surface of the 1 st adhesive layer 2 (for example, protruding toward the 2 nd adhesive layer 3), the distance from the surface 3a of the 2 nd adhesive layer 3 on the opposite side from the 1 st adhesive layer 2 side to the boundary S between the 1 st adhesive layer 2 and the 2 nd adhesive layer 3 located at the separated portion of the adjacent conductive particles 4, 4 (the distance denoted by d2 in fig. 1) is the thickness of the 2 nd adhesive layer 3.

The 3 rd adhesive layer 6 may contain a component (C). The (C1) component and the (C2) component used in the (C) component (i.e., the 3 rd thermosetting resin component) in the 3 rd adhesive layer are the same as the (C1) component and the (C2) component used in the (C) component (i.e., the 1 st thermosetting resin component) in the 1 st adhesive layer 2, and thus detailed description thereof is omitted here. The 3 rd thermosetting resin component may be the same as or different from the 1 st thermosetting resin component. The 3 rd thermosetting resin component may be the same as or different from the 2 nd thermosetting resin component.

From the viewpoint of imparting good transferability and peeling resistance, the content of the component (C) may be 5 mass% or more, 10 mass% or more, 15 mass% or more, or 20 mass% or more based on the total mass of the 3 rd adhesive layer. From the viewpoint of imparting good half-cut properties and blocking resistance (suppressing resin bleed-out of the roll), the content of the component (C) may be 70 mass% or less, 60 mass% or less, 50 mass% or less, or 40 mass% or less, based on the total mass of the 3 rd adhesive layer.

The 3 rd adhesive layer may further contain other components and other additives in the 1 st adhesive layer 2.

The content of the component (D) may be 10 mass% or more, 20 mass% or more, or 30 mass% or more, or 80 mass% or less, 70 mass% or less, or 60 mass% or less, based on the total mass of the 3 rd adhesive layer.

The content of the component (E) may be 0.1 to 10 mass% based on the total mass of the 3 rd adhesive layer.

(F) The content of the component (c) can be appropriately set within a range that does not impair the effects of the present invention.

The content of the other additive may be, for example, 0.1 to 10 mass% based on the total mass of the 3 rd adhesive layer.

The thickness of the 3 rd adhesive layer may be appropriately set according to the lowest melt viscosity of the adhesive film, the height of the electrodes of the bonded circuit member, and the like. The thickness of the 3 rd adhesive layer is preferably smaller than the thickness d2 of the 2 nd adhesive layer 3. The thickness of the 3 rd adhesive layer may be 0.2 μm or more or 3.0 μm or less from the viewpoint of sufficiently filling the space between the electrodes to seal the electrodes and obtaining more excellent connection reliability. The thickness of the 3 rd adhesive layer can be obtained by the same method as the method for measuring the thickness d1 of the 1 st adhesive layer 2, for example.

The thickness of the adhesive films 1a, 1b (the total thickness of all layers constituting the adhesive films 1a, 1b, the sum of the thickness d1 of the 1 st adhesive layer 2 and the thickness d2 of the 2 nd adhesive layer 3 in fig. 1 (a), and the sum of the thickness d1 of the 1 st adhesive layer 2, the thickness d2 of the 2 nd adhesive layer 3 and the thickness of the 3 rd adhesive layer in fig. 1 (b)) may be, for example, 5 μm or more and 8 μm or more and may be 30 μm or less and 20 μm or less.

In the adhesive films 1a, 1b, for example, the 1 st adhesive layer may be the above-described region P. In this case, the range of the thickness direction of the film in the region P can be made the same as the thickness d1 of the 1 st adhesive layer 2. The region P can be formed of a composition from which conductive particles are removed from the above composition for forming the 1 st adhesive layer.

In the adhesive films 1a, 1b, for example, the 2 nd adhesive layer may be the above-mentioned region a.

When the 2 nd adhesive layer is the region a, the thickness direction of the film of the region a can be set to have the same range as the thickness d2 of the 2 nd adhesive layer 3. The area a can be formed of the composition for forming the 2 nd adhesive layer described above.

In the adhesive films 1a, 1b, the 2 nd adhesive layer or the 2 nd and 3 rd adhesive layers may be the region S containing no conductive particles. The region S can be formed of the composition for forming the 2 nd adhesive layer, the composition for forming the 3 rd adhesive layer described above.

In the adhesive films 1a, 1b, an inorganic filler having a particle diameter D50 of 0.5 to 1.0 μm when 50% is accumulated and a particle diameter D95 of 0.9 to 2.0 μm when 95% is accumulated in the volume-based particle size distribution may be contained in the 2 nd adhesive layer, and not in the 1 st adhesive layer and the 3 rd adhesive layer.

The adhesive films 1a, 1b have a minimum melt viscosity of 450 to 1600 Pa.s. The minimum melt viscosity of the adhesive films 1a, 1b may be 500pa·s or more, 600pa·s or more, 700pa·s or more, or 800pa·s or more. When the minimum melt viscosity of the adhesive films 1a and 1b is 450pa·s or more, deformation of the plastic substrate at the time of thermocompression bonding can be suppressed, and occurrence of circuit breaking can be prevented. The minimum melt viscosity of the adhesive films 1a, 1b may be 1500pa·s or less, 1400pa·s or less, 1300pa·s or less, 1200pa·s or less, 1100pa·s or less, or 1000pa·s or less. When the minimum melt viscosity of the adhesive films 1a and 1b is 1600pa·s or less, the decrease in the exclusivity of the resin at the time of circuit connection can be suppressed, and therefore the connection resistance between the opposing electrodes of the circuit connection structure can be reduced, and good conduction characteristics can be ensured. The minimum melt viscosity of the adhesive film can be determined by the following method, for example.

(method for measuring minimum melt viscosity)

The adhesive films were laminated with a laminator so that the thickness became 200 μm or more, to obtain a laminate. The PET subjected to the mold release treatment was peeled from the laminate obtained and cut into 10.0 mm. Times.10.0 mm to obtain a measurement sample. The lowest melt viscosity of the obtained measurement sample was measured using a viscoelasticity measuring apparatus (trade name: ARES-G2, manufactured by TA Instruments, heating rate: 10 ℃ C./min).

In the adhesive films 1a, 1b, the 2 nd adhesive layer 3 generally has a thicker thickness than the 1 st adhesive layer 2. Therefore, the minimum melt viscosity of the adhesive films 1a and 1b tends to vary depending on the 2 nd adhesive layer 3. The minimum melt viscosity of the adhesive films 1a and 1b can be adjusted, for example, by adjusting the type, content, and the like of the constituent component (particularly, component (D)) included in the 2 nd adhesive layer 3. The minimum melt viscosity of the adhesive films 1a and 1b can be adjusted by, for example, blending the inorganic filler a as the component (F). By blending the inorganic filler a in the 2 nd adhesive layer 3, the lowest melt viscosity can be reduced while sufficiently suppressing the occurrence of large indentations.

In the adhesive films 1a, 1b, the conductive particles 4 are dispersed in the 1 st adhesive layer 2. Thus, the adhesive films 1a, 1b are anisotropic conductive adhesive films having anisotropic conductivity. The adhesive films 1a and 1b are interposed between a 1 st circuit member having a 1 st electrode and a 2 nd circuit member having a 2 nd electrode, and thermally press-bond the 1 st circuit member and the 2 nd circuit member to electrically connect the 1 st electrode and the 2 nd electrode to each other.

According to the adhesive films 1a and 1b, by setting the 2 nd adhesive layer 3 as the region a, even when the circuit members are connected to each other at a low pressure, conduction between the opposing electrodes of the circuit connection structure can be ensured, and occurrence of large indentations, which are a factor of failure determination by the automatic appearance inspection device, can be sufficiently suppressed.

The adhesive film for circuit connection of the present embodiment can be suitably used for COP mounting. More specifically, the present invention can be applied to connection between a plastic substrate on which a circuit electrode (for example, an electrode including Ti) is formed and an IC chip such as a driving IC in an organic EL display.

Method for producing adhesive film for circuit connection

The method for producing an adhesive film for circuit connection according to one embodiment may include, for example: a step (step 1) of irradiating a composition layer formed from a composition containing a component (A), a component (B), and a component (C) (a 1 st thermosetting resin component), and other components as necessary with light to form a 1 st adhesive layer; and a step (step 2) of laminating a step 2 of an adhesive layer containing a component (C) (a step 2) and an inorganic filler A, and other components as necessary, on the step 1 of the adhesive layer. The manufacturing method may further include the following step (step 3): a 3 rd adhesive layer containing a (C) component (3 rd thermosetting resin component), and if necessary, an inorganic filler a and other components is laminated on the opposite side of the 1 st adhesive layer from the 2 nd adhesive layer. In this case, the step 2 may be performed first, or the step 3 may be performed first. When the 3 rd step is first performed, the 3 rd adhesive layer is laminated on the side of the 1 st adhesive layer opposite to the side on which the 2 nd adhesive layer is to be laminated. Fig. 2 is a schematic cross-sectional view showing a manufacturing method including the above steps.

In step 1, for example, a varnish composition (varnish-like 1 st adhesive composition) is prepared by mixing and kneading a composition containing the component (a), the component (B), and the component (C), and optionally an additive in an organic solvent, and dissolving or dispersing the mixture. Then, the varnish composition is applied to the substrate subjected to the release treatment using an air knife coater, roll coater, applicator, corner-roll coater, die coater, or the like, and then the organic solvent is volatilized by heating, whereby a composition layer formed of the composition is formed on the substrate. In this case, the thickness of the 1 st adhesive layer (1 st adhesive film) to be finally obtained can be adjusted by adjusting the coating amount of the varnish composition. Then, the composition layer formed from the composition is irradiated with light to cure the component (B) in the composition layer, thereby forming the 1 st adhesive layer on the substrate. The 1 st adhesive layer can be referred to as a 1 st adhesive film. The 1 st adhesive layer 2 shown in fig. 2 (a) provided on the base material 22 can be prepared by the 1 st step.

The organic solvent used in the preparation of the varnish composition is not particularly limited as long as it has a property of uniformly dissolving or dispersing each component. Examples of such organic solvents include toluene, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, propyl acetate, butyl acetate, and the like. These organic solvents can be used singly or in combination of 2 or more. The stirring and mixing or kneading in preparing the varnish composition can be performed using, for example, a stirrer, a kneader (molecular machine), a three-roll mill, a ball mill, a bead mill, a homogenizing and dispersing machine, or the like.

The substrate is not particularly limited as long as it has heat resistance capable of withstanding the heating conditions at the time of volatilizing the organic solvent. As such a substrate, for example, a substrate (e.g., a film) formed of stretched polypropylene (OPP), polyethylene terephthalate (PET), polyethylene naphthalate, polyethylene isophthalate, polybutylene terephthalate, polyolefin, polyacetate, polycarbonate, polyphenylene sulfide, polyamide, polyimide, cellulose, ethylene/vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride, a synthetic rubber system, a liquid crystal polymer, or the like can be used.

The heating conditions for volatilizing the organic solvent from the varnish composition applied on the substrate can be appropriately set according to the organic solvent or the like used. The heating conditions may be, for example, 40 to 120℃and 0.1 to 10 minutes.

A part of the solvent may remain in the 1 st adhesive layer without being removed. The content of the solvent in the 1 st adhesive layer may be, for example, 10 mass% or less based on the total mass of the 1 st adhesive layer.

The content of the component (B) in the varnish composition may be 10% by mass or more and less than 60% by mass based on the total of the component (a) and the components other than the organic solvent in the varnish composition. In this case, the effect of suppressing the flow of the conductive particles is easily obtained, and the coating with good appearance is easily performed.

In the irradiation of light in the curing step, irradiation light (for example, ultraviolet light) having a wavelength in the range of 150 to 750nm is preferably used. The irradiation of light can be performed using, for example, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a xenon lamp, a metal halide lamp, an LED light source, or the like. The cumulative light amount of the light irradiation can be appropriately set, but may be, for example, 500 to 3000mJ/cm ² 。

The 2 nd step is a step of laminating a 2 nd adhesive layer on the 1 st adhesive layer. In step 2, for example, first, a 2 nd adhesive layer is formed on the substrate in the same manner as in step 1 except that the component (C) and the inorganic filler a are used and light irradiation is not performed, to obtain a 2 nd adhesive film. For example, the 2 nd adhesive layer 3 shown in fig. 2 (a) provided on the substrate 20 can be prepared. Next, the 1 st adhesive film and the 2 nd adhesive film are bonded to each other, whereby the 2 nd adhesive layer can be laminated on the 1 st adhesive layer (see fig. 2 (a) and (b)). In step 2, for example, a varnish composition (varnish-like adhesive composition 2) obtained by applying the component (C), the inorganic filler a, and other additives as necessary to the adhesive layer 1 is applied, and the organic solvent is volatilized, whereby the adhesive layer 2 can be laminated on the adhesive layer 1.

Examples of the method for bonding the 1 st adhesive film and the 2 nd adhesive film include hot pressing, roll lamination, vacuum lamination, and the like. The lamination can be performed, for example, under a temperature condition of 0 to 80 ℃.

A part of the solvent may remain in the 2 nd adhesive layer without being removed. The content of the solvent in the 2 nd adhesive layer may be, for example, 10 mass% or less based on the total mass of the 2 nd adhesive layer.

The 3 rd step is a step of laminating the 3 rd adhesive layer on the opposite side of the 1 st adhesive layer from the 2 nd adhesive layer. In the 3 rd step, for example, first, a 3 rd adhesive layer is formed on a substrate in the same manner as in the 2 nd step, to obtain a 3 rd adhesive film. For example, the 3 rd adhesive layer 6 shown in fig. 2 (c) provided on the base material 24 can be prepared. Next, a 3 rd adhesive film is laminated on the side of the 1 st adhesive film opposite to the 2 nd adhesive film, whereby the 3 rd adhesive layer can be laminated on the side of the 1 st adhesive layer opposite to the 2 nd adhesive layer (refer to fig. 2 (c)). In step 3, for example, a varnish composition (varnish-like 3 rd adhesive composition) is applied to the side of the 1 st adhesive layer opposite to the 2 nd adhesive layer in the same manner as in step 2, and the organic solvent is volatilized, whereby the 3 rd adhesive layer can be laminated on the 1 st adhesive layer. The bonding method and conditions are the same as those in step 2.

A part of the solvent may remain in the 3 rd adhesive layer without being removed. The content of the solvent in the 3 rd adhesive layer may be, for example, 10 mass% or less based on the total mass of the 3 rd adhesive layer.

Inorganic filler-containing composition

The inorganic filler-containing composition of the present embodiment contains an inorganic filler having a particle diameter D50 of 0.5 to 1.0 μm when 50% is accumulated and a particle diameter D95 of 0.9 to 2.0 μm when 95% is accumulated in a volume-based particle size distribution. The inorganic filler can be the same as the inorganic filler a described above.

The inorganic filler-containing composition of the present embodiment can be used to form an inorganic filler-containing region in a circuit-connecting member containing conductive particles and an inorganic filler. The circuit-connecting member includes the above-mentioned adhesive film for circuit connection. The inorganic filler-containing composition according to the present embodiment can form the above-described region a and the 2 nd adhesive layer as the inorganic filler-containing region.

The composition of the inorganic filler-containing composition of the present embodiment can be set in the same manner as the composition in the 2 nd adhesive layer described above. For example, the composition may further contain a thermoplastic resin.

The inorganic filler-containing composition of the present embodiment may be a varnish composition (varnish-like inorganic filler-containing composition) containing the above-described organic solvent.

The inorganic filler-containing composition of the present embodiment can be used to form an adhesive layer having a thickness of 10 μm or less, 9 to 4 μm or 8 to 5 μm. According to the inorganic filler-containing composition of the present embodiment, even when the coating is performed at such a design thickness, appearance defects such as scratches are less likely to occur, and a high coating yield can be obtained.

Circuit connection structure and method for manufacturing the same

The circuit connection structure using the adhesive film 1a for circuit connection as a circuit connection material and a method for manufacturing the same will be described below.

Fig. 3 is a schematic cross-sectional view showing an embodiment of the circuit connection structure. As shown in fig. 3, the circuit connection structure 10 includes: a 1 st circuit member 13 having a 1 st electrode 12 formed on the 1 st circuit substrate 11 and a main surface 11a of the 1 st circuit substrate 11; a 2 nd circuit member 16 having a 2 nd electrode 15 formed on the 2 nd circuit substrate 14 and the main surface 14a of the 2 nd circuit substrate 14; and a circuit connection portion 17 disposed between the 1 st circuit member 13 and the 2 nd circuit member 16 to electrically connect the 1 st electrode 12 and the 2 nd electrode 15 to each other.

The 1 st circuit member 13 and the 2 nd circuit member 16 may be identical to each other or may be different from each other. The 1 st circuit member 13 and the 2 nd circuit member 16 may be glass substrates or plastic substrates on which circuit electrodes are formed; a printed wiring board; a ceramic circuit board; a flexible circuit board; an IC chip such as a driving IC. The 1 st circuit board 11 and the 2 nd circuit board 14 may be formed of an inorganic material such as a semiconductor, glass, or ceramic, an organic material such as polyimide, polycarbonate, or a composite material such as glass/epoxy. The 1 st circuit substrate 11 may be a plastic substrate. The 1 st circuit member 13 may be, for example, a plastic substrate (a plastic substrate formed of an organic material such as polyimide, polycarbonate, polyethylene terephthalate, or cyclic olefin polymer) on which a circuit electrode is formed, and the 2 nd circuit member 16 may be, for example, an IC chip such as a driving IC. The plastic substrate having the electrodes formed thereon can form a display region by, for example, regularly arranging pixel driving circuits such as organic TFTs or a plurality of organic EL elements R, G, B in a matrix form on the plastic substrate.

The 1 st electrode 12 and the 2 nd electrode 15 may be electrodes containing metals such as gold, silver, tin, ruthenium, rhodium, palladium, osmium, iridium, platinum, copper, aluminum, molybdenum, titanium, or the like, oxides such as Indium Tin Oxide (ITO), indium Zinc Oxide (IZO), indium Gallium Zinc Oxide (IGZO), or the like. The 1 st electrode 12 and the 2 nd electrode 15 may be electrodes formed by stacking 2 or more of these metals, oxides, and the like. The number of electrodes formed by stacking 2 or more kinds may be 2 or more, or 3 or more. In the case where the 1 st circuit member 13 is a plastic substrate, the 1 st electrode 12 may be an electrode containing Ti, more specifically, an electrode having a titanium layer on the outermost surface. The 1 st electrode 12 and the 2 nd electrode 15 may be circuit electrodes or bump electrodes. At least one of the 1 st electrode 12 and the 2 nd electrode 15 may be a bump electrode. In fig. 3, the 1 st electrode 12 is a circuit electrode, and the 2 nd electrode 15 is a bump electrode.

The circuit connection portion 17 includes a cured product of the adhesive film 1 a. The circuit connection portion 17 may be formed of a cured product of the adhesive film 1 a. The circuit connection unit 17 includes, for example: the 1 st region 18, which is located on the 1 st circuit member 13 side in a direction in which the 1 st circuit member 13 and the 2 nd circuit member 16 face each other (hereinafter, referred to as "facing direction"), is formed of a cured product of the component (B) and a cured product of the component (C) other than the conductive particles 4 in the 1 st adhesive layer; a 2 nd region 19 which is located on the 2 nd circuit member 16 side in the opposing direction and is formed of a cured product of the (C) component or the like in the 2 nd adhesive layer; and conductive particles 4 interposed at least between the 1 st electrode 12 and the 2 nd electrode 15 to electrically connect the 1 st electrode 12 and the 2 nd electrode 15 to each other. As shown in fig. 3, the circuit connection portion 17 does not necessarily have 2 distinct regions between the 1 st region 18 and the 2 nd region 19, and may be formed by mixing a cured product derived from the 1 st adhesive layer and a cured product derived from the 2 nd adhesive layer.

The circuit connection structure may be one of the 1 st circuit member and the 2 nd circuit member, which is an IC chip, and the other is a plastic substrate having an electrode including Ti. Examples of the circuit connection structure include a flexible organic electroluminescent color display (organic EL display) in which a plastic substrate on which organic EL elements are regularly arranged is connected to a driving circuit element as an image display driver, and a touch panel in which a plastic substrate on which organic EL elements are regularly arranged is connected to an input element such as a touch panel. The circuit connection structure can be applied to various monitors such as smart phones, tablet computers, televisions, navigation systems of vehicles, wearable terminals and the like; furniture; household appliances; daily necessities, and the like.

Fig. 4 is a schematic cross-sectional view showing an embodiment of a method for manufacturing a circuit connection structure. Fig. 4 (a) and 4 (b) are schematic cross-sectional views showing the respective steps. As shown in fig. 4, the method for manufacturing the circuit connection structure 10 includes the steps of: the adhesive film 1a is interposed between the 1 st circuit member 13 having the 1 st electrode 12 and the 2 nd circuit member 16 having the 2 nd electrode 15, and the 1 st circuit member 13 and the 2 nd circuit member 16 are thermally press-bonded to electrically connect the 1 st electrode 12 and the 2 nd electrode 15 to each other.

Specifically, as shown in fig. 4 (a), first, a 1 st circuit component 13 including a 1 st electrode 12 formed on a 1 st circuit substrate 11 and a main surface 11a of the 1 st circuit substrate 11 and a 2 nd circuit component 16 including a 2 nd electrode 15 formed on a 2 nd circuit substrate 14 and a main surface 14a of the 2 nd circuit substrate 14 are prepared.

Next, the 1 st circuit member 13 and the 2 nd circuit member 16 are arranged so that the 1 st electrode 12 and the 2 nd electrode 15 face each other, and the adhesive film 1a is arranged between the 1 st circuit member 13 and the 2 nd circuit member 16. For example, as shown in fig. 4 (a), the 1 st adhesive layer 2 side is opposed to the main surface 11a of the 1 st circuit board 11, and the adhesive film 1a is laminated on the 1 st circuit member 13. Next, the 2 nd circuit member 16 is disposed on the 1 st circuit member 13 on which the adhesive film 1a is laminated so that the 1 st electrode 12 on the 1 st circuit substrate 11 and the 2 nd electrode 15 on the 2 nd circuit substrate 14 face each other.

As shown in fig. 4 (b), the 1 st circuit member 13, the adhesive film 1a, and the 2 nd circuit member 16 are heated, and the 1 st circuit member 13 and the 2 nd circuit member 16 are pressed in the thickness direction, whereby the 1 st circuit member 13 and the 2 nd circuit member 16 are thermally pressed against each other. At this time, as shown by the arrow in fig. 4 (b), the 2 nd adhesive layer 3 has a flowable uncured thermosetting component, and is cured by the above-mentioned heating while flowing so as to fill the gaps between the 2 nd electrodes 15. Thus, the 1 st electrode 12 and the 2 nd electrode 15 are electrically connected to each other via the conductive particles 4, and the 1 st circuit member 13 and the 2 nd circuit member 16 are bonded to each other, whereby the circuit connection structure 10 shown in fig. 3 can be obtained. In the method for manufacturing the circuit connection structure 10 according to the present embodiment, it can be said that the 1 st adhesive layer 2 is partially cured by light irradiation, and therefore, the flow of the conductive particles in the 1 st adhesive layer 2 is suppressed, the 1 st adhesive layer 2 hardly flows at the time of the thermocompression bonding, and the conductive particles are efficiently trapped between the opposed electrodes, so that the connection resistance between the opposed 1 st electrode 12 and the 2 nd electrode 15 can be reduced. Further, if the 1 st adhesive layer has a thickness of 5 μm or less, conductive particles at the time of circuit connection tend to be more efficiently captured.

Further, the inorganic filler a is contained in the 2 nd adhesive layer 3 to obtain high fluidity, so that the connection resistance between the 1 st electrode 12 and the 2 nd electrode 15 facing each other can be reduced, and the occurrence of large indentations can be sufficiently suppressed.

The heating temperature at the time of thermocompression bonding can be appropriately set, but may be, for example, 50 to 190 ℃. The pressurization is not particularly limited as long as it does not damage the adherend, but in the case of COP mounting, for example, the area conversion pressure on the bump electrode may be 0.1 to 50MPa, 40MPa or less, or 0.1 to 40MPa. In the case of COG mounting, for example, the area conversion pressure on the bump electrode may be 10 to 100MPa. These heating and pressurizing times may be in the range of 0.5 to 120 seconds.

Examples

The present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

[ production of 1 st adhesive layer, 2 nd adhesive layer and 3 rd adhesive layer ]

The following materials were used for the production of the 1 st adhesive layer, the 2 nd adhesive layer, and the 3 rd adhesive layer.

< preparation of conductive particles >)

The surface of a plastic core of 3 μm was subjected to Ni plating of 80nm, and the surface of the plastic core was subjected to substitution plating of 20nm with Pd. Thus, conductive particles having an average particle diameter of 3.2 μm were obtained.

(A) The components are as follows: conductive particles

A-1: the conductive particles produced as described above

(B) The components are as follows: photocurable resin component

(B1) The components are as follows: radical polymerizable compound

B1-1: NK Ester A-BPEF70T (ethoxylated fluorene-type di (meth) acrylate (2 function), SHIN-NAKAMURA CHEMICAL CO, LTD. Manufactured) was diluted with toluene to a nonvolatile content of 70 mass%

B1-2: RIPOXY VR-90 (bisphenol A epoxy (meth) acrylate (2 functional) (vinyl ester resin), manufactured by SHOWA DENKO K.K.)

(B2) The components are as follows: photo radical polymerization initiator

B2-1: irgacure OXE-02 (ethanone, 1- [ 9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl ] -,1- (o-acetyl oxime), manufactured by BASF Co., ltd.) was diluted with MEK to a nonvolatile matter having 10% by mass

(C) The components are as follows: thermosetting resin component

(C1) The components are as follows: cationically polymerizable compound

C1-1: ETERNACOLL OXBP (3-ethyl-3-hydroxymethyl oxetane, manufactured by UBE Corporation)

C1-2: EHPE3150 (1, 2-epoxy-4- (2-epoxyethyl) cyclohexane adduct of 2, 2-bis (hydroxymethyl) -1-butanol, manufactured by Daicel Corporation)

C1-3: CELLOXIDE2021P (3, 4-epoxycyclohexylmethyl (3, 4-epoxygroup) cyclohexanecarboxylate, manufactured by Daicel Corporation)

C1-4: OXSQ-TX100 (Poly ({ 3- [ (3-ethyl-3-oxetanyl) methoxy ] propyl } silsesquioxane) derivative, TOAGOSEI CO., LTD. Manufactured)

C1-5: CELLOXIDE8010 (bis-7-oxabicyclo [4.1.0] heptane, manufactured by Daicel Corporation)

(C2) The components are as follows: thermal cationic polymerization initiator

C2-1: CXC-1821 (King Industries, inc.)

(D) The components are as follows: thermoplastic resin

D-1: phenoTohto YP-50S (bisphenol A type phenoxy resin, weight average molecular weight: 60,000, glass transition temperature: 84 ℃ C., NIPPON STEEL Chemical & Material Co., ltd.) was diluted with MEK to a nonvolatile matter of 40 mass%

D-2: TOPR-300 (high Tg type epoxy resin, epoxy equivalent: 900-1,000, softening point: 120 ℃ C., NIPPON STEEL Chemical & Material Co., ltd.) was a Material diluted with MEK to a nonvolatile content of 60% by mass

D-3: phenoTohto FX-293 (fluorene skeleton-containing phenoxy resin, weight average molecular weight: 45,000, glass transition temperature: 158 ℃ C., NIPPON STEEL Chemical & Material Co., ltd.) was diluted with MEK to a nonvolatile matter of 60 mass%

D-4: phenoTohto ZX-1356-2 (bisphenol A and bisphenol F copolymerized phenoxy resin, weight average molecular weight: 70000, glass transition temperature: 71 ℃ C., NIPPON STEEL Chemical & Material Co., ltd.) was diluted with MEK to a nonvolatile matter of 40 mass%

(E) The components are as follows: coupling agent

E-1: SH-6040 (3-glycidoxypropyl trimethoxysilane, manufactured by Dow Corning Toray Co., ltd.)

(F) The components are as follows: filling material

(F1) The components are as follows: inorganic filler

F-1: ADMAFINE SE2050 (silica filler, manufactured by Admatechs Company Limited) in which particles of 1 μm or more are reduced as much as possible by air classification, and then diluted with MEK to a nonvolatile matter of 70 mass%

F-2: ADMAFINE SE2050 (silica filler, manufactured by Admatechs Company Limited) was diluted with MEK to a nonvolatile content of 70% by mass

F-3: admanno YA050C (silica filler, manufactured by Admatechs Company Limited) diluted with MEK to a nonvolatile matter of 50 mass%

F-4: AEROSIL R805 (silica filler, manufactured by Evonik Industries AG) was diluted with MEK to a nonvolatile matter of 10% by mass

< determination of particle size distribution of inorganic filler-1 >

The particle diameter D50 at 50% cumulative time (particle diameter of cumulative 50 vol%) and the particle diameter D95 at 95% cumulative time (particle diameter of cumulative 95 vol%) in the volume-based particle size distribution of the inorganic filler were measured. In the measurement, microtroac MT3300EXII manufactured by Nikkiso co., ltd. Was used as a measurement device, and methyl ethyl ketone was used as a measurement solvent.

TABLE 1

< preparation of 1 st adhesive layer >

After obtaining a composition obtained by mixing the materials shown in table 2 in the composition ratio (mass ratio) (the numerical values in table 2 refer to the nonvolatile component amounts), the composition layers formed from the compositions containing the respective components were obtained by applying a magnetic field to a release-treated PET (polyethylene terephthalate) film, and then drying the film with hot air at 70 ℃ for 5 minutes with an organic solvent or the like. The composition layers were coated so that the thickness after drying became 3 to 4 μm, respectively. Then, the composition layers were irradiated with light (UV irradiation: metal halide lamp, cumulative light amount: 2100 mJ/cm) ² ) Thus, the 1 st adhesive layer in which the conductive particles were dispersed was produced. Here, the thickness is measured using a contact thickness gauge.

In addition, when the thickness of the layer formed of the 1 st adhesive composition or the adhesive layer is smaller than the thickness (diameter) of the conductive particles, if the thickness of the layer is measured by a contact thickness meter, the thickness of the conductive particles is reflected and the thickness of the region where the conductive particles exist is measured. Therefore, after the adhesive film having a two-layer structure in which the 1 st adhesive layer and the 2 nd adhesive layer are laminated was produced, the thickness of the 1 st adhesive layer located at the separated portion of the adjacent conductive particles was measured by a method described later using a scanning electron microscope.

TABLE 2

< preparation of the 2 nd adhesive layer >

After obtaining a composition obtained by mixing the materials shown in table 3 in the composition ratio (mass ratio) (the numerical values of table 3 refer to the nonvolatile component amounts.) shown in table 3, a release-treated PET (polyethylene terephthalate) film was coated, and an organic solvent or the like was dried with hot air at 70 ℃ for 5 minutes, thereby producing 2 nd adhesive layers each formed of the composition containing each component. The adhesive layers are coated so that the thickness after drying becomes 8 to 9 μm, respectively. Here, the thickness is measured using a contact thickness gauge.

(coating yield)

The coating yield at the time of forming the 2 nd adhesive layer was determined as a proportion Y (%) in which white lines and scratches were not generated, and evaluated according to the following criteria.

A+: y is more than 95%

A: y is more than 90% and less than 95%

B: y is 80% or more and less than 90%

C: y is less than 80%

TABLE 3

< determination of particle size distribution of inorganic filler-2 >

Regarding the inorganic filler (mixture of 80 parts by mass of F-1 and 5 parts by mass of F-3) contained in the composition S1-4, the particle diameter D50 at 50% cumulative (particle diameter at 50% cumulative distribution) and the particle diameter D95 at 95% cumulative (particle diameter at 95% cumulative distribution) in the volume-based particle size distribution were measured in the same manner as described above.

TABLE 4

< preparation of the 3 rd adhesive layer >

After obtaining a composition obtained by mixing the materials shown in table 5 in the composition ratio (mass ratio) (the numerical values in table 5 refer to the nonvolatile component amounts), the release-treated PET (polyethylene terephthalate) film was coated, and an organic solvent or the like was dried with hot air at 70 ℃ for 5 minutes, thereby producing the 3 rd adhesive layer formed of the composition containing each component. The adhesive layers are coated so that the thickness after drying becomes 0.5 to 1.5 μm, respectively. Here, the thickness is measured using a contact thickness gauge.

TABLE 5

(examples 1 to 5 and comparative examples 1 to 5)

[ production of adhesive film ]

An adhesive film having the structure shown in table 6 was produced using the 1 st adhesive layer, the 2 nd adhesive layer, and the 3 rd adhesive layer produced as described above. For example, in the adhesive film of example 1, the 1 st adhesive layer formed of the composition P-1 was bonded to the 2 nd adhesive layer formed of the composition S1-1 while applying a temperature of 50 to 60℃to peel off the PET film on the 1 st adhesive layer side. Next, the 3 rd adhesive layer formed of the composition S2-1 was bonded to the exposed 1 st adhesive layer while applying a temperature of 50 to 60 ℃, to obtain an adhesive film of example 1. In order to easily peel the PET film peeled in these series of steps and the PET film peeled at the time of circuit connection, each PET film was selected so that the peel force between the 2 nd adhesive layer and the PET film was larger than the peel force between the 1 st adhesive layer and the PET film and the peel force between the 3 rd adhesive layer and the PET film.

With respect to the adhesive films of examples 2 to 4 and comparative examples 1 to 4, adhesive films having the structures shown in table 6 were produced in the same manner as in example 1. An adhesive film having the structure shown in table 6 was produced in the same manner as in example 1 except that the 3 rd adhesive layer was not bonded to example 5 and comparative example 5.

The thickness of the 1 st adhesive layer of the prepared adhesive film for circuit connection was measured by the following method. First, an adhesive film for circuit connection was sandwiched between 2 pieces of glass (thickness: about 1 mm), and a resin composition composed of 100g of bisphenol a type epoxy resin (trade name: JER, manufactured by Mitsubishi Chemical Corporation) and 10g of diethylenetriamine (Tokyo Chemical Industry co., manufactured by ltd.) was injected. Then, cross-sectional polishing was performed using a grinder, and the thickness of the 1 st adhesive layer located at the divided portions of adjacent conductive particles was measured using a scanning electron microscope (SEM, trade name: SE-8010,Hitachi High-Tech Science Corporation). The 1 st adhesive layer had a thickness of 1.8. Mu.m.

As for the adhesive films obtained in examples 1 to 5 and comparative examples 1 to 5, the projected particle densities were measured and found to be about 18000 particles/mm ² 。

[ evaluation of Circuit connection Structure ]

< manufacturing of Circuit connection Structure-1 >

As the 1 st circuit component, IC chips (0.9 mm. Times.20.3 mm, thickness: 0.3mm, bump electrode size: 70. Mu.m.times.12 μm, bump electrode thickness: 9 μm) were prepared in which bump electrodes were arranged in 2 rows in a staggered manner. As a 2 nd circuit component, a polyimide substrate (DU PONT-touay co., ltd. Manufactured, 200H) (38 mm×28mm, thickness: 0.05 mm) was prepared, on the surface of which Ti:50nm/Al:400nm wiring pattern (pattern width: 19 μm, inter-electrode space: 5 μm).

The circuit connection structure was produced using the adhesive films of examples 1 to 5 and comparative examples 1 to 5. The adhesive film was cut to a width of 2.0mm, and the adhesive film was disposed on the 1 st circuit member so that the 3 rd adhesive layer (in the case of example 5 and comparative example 5, the 2 nd adhesive layer) was in contact with the 1 st circuit member. A thermocompression bonding apparatus composed of a stage including a ceramic heater and a tool (8 mm. Times.50 mm) was used at 70℃and 0.98MPa (10 kgf/cm ² ) The adhesive film was bonded to the 1 st circuit member under heating and pressure for 2 seconds, and the release film on the side of the adhesive film opposite to the 1 st circuit member was peeled off. Then, the bump electrode of the 1 st circuit component and the 2 nd circuit component are performed After alignment of the wiring patterns of the circuit members, the 1 st adhesive layer of the adhesive film was bonded to the 2 nd circuit member by heating and pressurizing for 5 seconds with a Teflon (registered trademark) having a thickness of 50 μm as a buffer material under conditions that the actual measurement temperature of the adhesive film was 170℃at the maximum and the area conversion pressure on the bump electrode was 30MPa, using a heating tool, thereby producing circuit connection structures-1, respectively.

< manufacturing of Circuit connection Structure-2 >

As the 1 st circuit component, IC chips (0.9 mm. Times.20.3 mm, thickness: 0.3mm, bump electrode size: 70. Mu.m.times.12 μm, bump electrode space: 12 μm, bump electrode thickness: 5 μm) were prepared in which bump electrodes were arranged in 2 rows in a staggered manner. Further, as the 2 Nd circuit member, a member in which Al/Nd having a thickness of 150nm was formed on the surface of a glass substrate (25 mm. Times.35 mm, thickness: 0.2 mm) was prepared.

Except that the 1 st circuit member and the 2 nd circuit member were used, the circuit connection structures-2 were produced using the adhesive films of examples 1 to 5 and comparative examples 1 to 5, respectively, in the same manner as the production of the circuit connection structures-1.

(evaluation of connection resistance)

With respect to the produced circuit connection structure-1, the initial connection resistance (on-resistance) was measured by the four-terminal method. For the measurement, a multimeter MLR21 manufactured by Kusumoto Chemicals, ltd. The potential difference was measured at any 14 points, and the average value was obtained. The average value of the potential difference was converted into a connection resistance value, and evaluated according to the following criteria. The results are shown in Table 6.

A: the connection resistance value is less than 0.6Ω

B: the connection resistance value is more than 0.6Ω and less than 1.0Ω

C: the connection resistance value is more than 1.0 omega

(evaluation of large indentation)

The circuit connection structure-2 thus fabricated was observed from the glass substrate side by using a differential interference microscope, and it was confirmed whether or not there was an indentation (large indentation) significantly stronger than the indentation of the conductive particles (visually significant), and the case where such large indentation was not observed was evaluated as "a", and the case where such large indentation was observed was evaluated as "B".

TABLE 6

< preparation of 1 st adhesive layer-B >

After obtaining a composition obtained by mixing the materials shown in table 7 in the composition ratio (mass ratio) (the numerical values of table 7 refer to the nonvolatile component amounts.) shown in table 7, a release-treated PET (polyethylene terephthalate) film was coated, and an organic solvent or the like was dried with hot air at 70 ℃ for 5 minutes, thereby obtaining composition layers each formed of the composition containing the components. The composition layer was applied so that the thickness after drying became 5. Mu.m, thereby producing the 1 st adhesive layer-B. Here, the thickness is measured using a contact thickness gauge.

TABLE 7

< preparation of 2 nd adhesive layer-B >

After obtaining a composition obtained by mixing the materials shown in table 8 in the composition ratio (mass ratio) (the numerical values in table 8 refer to the nonvolatile component amounts), a release-treated PET (polyethylene terephthalate) film was coated, and an organic solvent or the like was dried with hot air at 70 ℃ for 5 minutes, thereby producing a 2 nd adhesive layer-B formed of the composition containing each component, respectively. The adhesive layers were coated so that the thickness after drying became 11 μm, respectively. Here, the thickness is measured using a contact thickness gauge.

(coating yield)

The coating yield at the time of forming the 2 nd adhesive layer-B was determined as a proportion Y (%) in which white lines and scratches were not generated, and evaluated according to the following criteria.

A+: y is more than 95%

A: y is more than 90% and less than 95%

B: y is 80% or more and less than 90%

C: y is less than 80%

TABLE 8

(example 6 and comparative examples 6 to 8)

[ production of adhesive film ]

The 1 st adhesive layer-B and the 2 nd adhesive layer-B prepared as described above were used to prepare adhesive films having the structures shown in table 9. For example, in the adhesive film of example 6, the 1 st adhesive layer-B formed of the composition P-2 was bonded to the 2 nd adhesive layer-B formed of the composition S1-9 while applying a temperature of 50 to 60 ℃ to obtain the adhesive film of example 6.

With respect to the adhesive films of comparative examples 6 to 8, adhesive films having the structures shown in table 9 were produced in the same manner as in example 6.

< manufacturing of Circuit connection Structure-3 >

As the 1 st circuit component, IC chips (0.9 mm. Times.20.3 mm, thickness: 0.3mm, bump electrode size: 70. Mu.m.times.12 μm, bump electrode space: 12 μm, bump electrode thickness: 5 μm) were prepared in which bump electrodes were arranged in 2 rows in a staggered manner. As the 2 nd circuit member, a member in which Ti/Al/Ti having a thickness of 150nm was formed on the surface of a glass substrate (25 mm. Times.35 mm, thickness: 0.2 mm) was prepared.

The circuit connection structure was produced using the adhesive films of example 6 and comparative examples 6 to 8. The adhesive film was cut to a width of 2.0mm, and the adhesive film was disposed on the 1 st circuit member so that the 2 nd adhesive layer-B was connected to the 1 st circuit member. A thermocompression bonding apparatus composed of a stage including a ceramic heater and a tool (8 mm. Times.50 mm) was used at 70℃and 0.98MPa (10 kgf/cm ² ) Is heated and pressurized for 2 secondsAnd (3) attaching the adhesive film to the 1 st circuit member, and peeling the release film on the opposite side of the adhesive film from the 1 st circuit member. Next, after the bump electrode of the 1 st circuit member and the wiring pattern of the 2 nd circuit member were aligned, the 1 st adhesive layer of the adhesive film was bonded to the 2 nd circuit member by heating and pressurizing the adhesive film for 5 seconds with a temperature of 145 ℃ at the maximum in actual measurement of the adhesive film and an area conversion pressure of 30MPa on the bump electrode using a Teflon (registered trademark) having a thickness of 50 μm as a buffer material with a heating tool of 8mm×45mm, thereby producing the circuit connection structures-3, respectively.

(evaluation of connection resistance)

The initial connection resistance (on-resistance) of the fabricated circuit connection structure 3 was measured by a four-terminal method. For the measurement, a multimeter MLR21 manufactured by Kusumoto Chemicals, ltd. The potential difference was measured at any 14 points, and the average value was obtained. The average value of the potential difference was converted into a connection resistance value, and evaluated according to the following criteria. The results are shown in Table 9.

A: the connection resistance value is less than 5 omega

B: the connection resistance value is more than 5 omega and less than 10 omega

C: the connection resistance value is more than 10Ω

(evaluation of large indentation)

The circuit connection structure-3 produced was observed from the glass substrate side by using a differential interference microscope to confirm whether or not an indentation (large indentation) was significantly stronger (visually apparent) than the indentation of the conductive particle, and the case where such a large indentation was not observed was evaluated as "a", and the case where such a large indentation was observed was evaluated as "B".

TABLE 9

Symbol description

1a, 1 b-adhesive film for circuit connection, 2-1 st adhesive layer, 3-2 nd adhesive layer, 4-conductive particles, 6-3 rd adhesive layer, 10-circuit connection structure, 12-circuit electrode (1 st electrode), 13-1 st circuit member, 15-bump electrode (2 nd electrode), 16-2 nd circuit member, 20, 22, 24-substrate.

Claims (14)

1. An adhesive film for circuit connection, which comprises conductive particles,

the adhesive film includes a region A containing an inorganic filler in the thickness direction of the film,

the region A is formed of a thermosetting composition containing an inorganic filler having a particle diameter D50 of 0.5 to 1.0 μm when 50% is accumulated and a particle diameter D95 of 0.9 to 2.0 μm when 95% is accumulated in a volume-based particle size distribution.

2. The adhesive film for circuit connection according to claim 1, wherein,

the adhesive film includes a region S containing no conductive particles in the thickness direction of the film,

the region a is provided in at least a part of the region S.

3. The adhesive film for circuit connection according to claim 1 or 2, wherein,

the inorganic filler is a silica filler.

4. An adhesive film for circuit connection, comprising: a 1 st adhesive layer containing conductive particles, a cured product of a photocurable resin component, and a 1 st thermosetting resin component; and a 2 nd adhesive layer provided on the 1 st adhesive layer and containing a 2 nd thermosetting resin component,

the 2 nd adhesive layer is formed from an inorganic filler-containing composition containing the 2 nd thermosetting resin component and an inorganic filler having a particle diameter D50 of 0.5 to 1.0 [ mu ] m at 50% accumulation and a particle diameter D95 of 0.9 to 2.0 [ mu ] m at 95% accumulation in a volume-based particle size distribution.

5. The adhesive film for circuit connection according to claim 4, wherein,

the inorganic filler is a silica filler.

6. The adhesive film for circuit connection according to claim 4 or 5, further comprising a 3 rd adhesive layer which is laminated on the opposite side of the 1 st adhesive layer from the 2 nd adhesive layer and contains a 3 rd thermosetting resin component.

7. An inorganic filler-containing composition for forming an inorganic filler-containing region in a circuit connecting member containing conductive particles and an inorganic filler,

the composition contains an inorganic filler having a particle diameter D50 of 0.5 to 1.0 [ mu ] m when 50% is accumulated and a particle diameter D95 of 0.9 to 2.0 [ mu ] m when 95% is accumulated in a volume-based particle size distribution.

8. The inorganic filler-containing composition according to claim 7, wherein,

the inorganic filler is a silica filler.

9. The inorganic filler-containing composition according to claim 7 or 8, further comprising a thermoplastic resin.

10. The inorganic filler-containing composition according to any one of claims 7 to 9, which is used for forming an adhesive layer having a thickness of 10 μm or less.

11. A method for manufacturing a circuit connection structure includes the steps of: the adhesive film for circuit connection according to any one of claims 1 to 6 is interposed between a 1 st circuit member having a 1 st electrode and a 2 nd circuit member having a 2 nd electrode, and the 1 st circuit member and the 2 nd circuit member are thermally press-bonded to electrically connect the 1 st electrode and the 2 nd electrode to each other.

12. The method for manufacturing a circuit connection structure according to claim 11, wherein,

one of the 1 st circuit part and the 2 nd circuit part is an IC chip, and the other is a plastic substrate having an electrode including Ti.

13. A circuit connection structure is provided with:

a 1 st circuit part having a 1 st electrode;

a 2 nd circuit part having a 2 nd electrode; a kind of electronic device with high-pressure air-conditioning system

A circuit connection portion disposed between the 1 st circuit member and the 2 nd circuit member to electrically connect the 1 st electrode and the 2 nd electrode to each other,

the circuit connection part comprises a cured product of the adhesive film for circuit connection according to any one of claims 1 to 6.

14. The circuit connection structure according to claim 13, wherein,

one of the 1 st circuit part and the 2 nd circuit part is an IC chip, and the other is a plastic substrate having an electrode including Ti.

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