阅读说明：本技术 安装体 (Mounting body ) 是由 冈部祐辅 于 2018-10-23 设计创作，主要内容包括：本发明提供一种安装体,其即使在施加使得基板屈曲的那样的外力的情况下,也可确保元件与电连接于该元件的导电部件之间的电连接的可靠性。具备：绝缘基材10；元件20,所述元件20介由导电部件30而装载于绝缘基材10；以及包覆部40,所述包覆部40将导电部件30的侧面以及元件的侧面的至少一部分包覆,且将导电部件30与元件20的边界的至少一部分包覆,所述包覆部40设置成相接于绝缘基材10的表面10a,弹性模量为0.1MPa以上且500MPa以下。(The invention provides a mounting body which can ensure the reliability of the electrical connection between an element and a conductive component electrically connected to the element even under the condition that an external force for buckling a substrate is applied. The disclosed device is provided with: an insulating base material 10; a device 20, wherein the device 20 is mounted on the insulating base 10 via the conductive member 30; and a covering portion 40 that covers at least a part of the side surface of the conductive member 30 and the side surface of the element, and that covers at least a part of the boundary between the conductive member 30 and the element 20, wherein the covering portion 40 is provided so as to contact the surface 10a of the insulating base 10, and has an elastic modulus of 0.1MPa to 500 MPa.)

1. A mounting body is provided with:

an insulating base material;

an element mounted on the insulating base material with a conductive member interposed therebetween; and

and a covering portion that covers at least a part of a side surface of the conductive member and a side surface of the element and covers at least a part of a boundary between the conductive member and the element, the covering portion being provided so as to be in contact with a surface of the insulating base material, and having an elastic modulus of 0.1MPa to 500 MPa.

2. The mount according to claim 1, wherein the insulating base material has flexibility, and the covering portion deforms in accordance with an external force.

3. The mounted body according to claim 1 or 2, wherein the insulating base material is a flexible substrate, and the conductive member is a low-temperature-curable conductive paste.

4. A mounting body according to any one of claims 1 to 3,

the coating part is formed by using a curable composition,

the curable composition has a viscosity of 10Pa · s or more and 100Pa · s or less before curing.

5. An electronic device comprising the mounting body according to any one of claims 1 to 4.

6. A curable composition for a covering portion of a mounted body, the mounted body comprising:

an insulating base material;

an element mounted on the insulating base material with a conductive member interposed therebetween; and

a covering portion that covers a side surface of the conductive member and at least a part of a side surface of the element and covers at least a part of a region including a boundary between the conductive member and the element, the covering portion being provided so as to be in contact with a surface of the insulating base material;

the curable composition has an elastic modulus of 0.1MPa or more and 500MPa or less after curing.

Technical Field

The present invention relates to a mounting body. The present invention particularly relates to a mounting body having a covering portion for alleviating an external force.

Background

Conventionally, there is known a semiconductor device mounting body including: a semiconductor device having an electrode pad (pad), a substrate having a terminal electrode, a bump electrode provided on the electrode pad of the semiconductor device, a conductive adhesive layer composed of a conductive adhesive having flexibility and electrically connecting the bump electrode and the terminal electrode on the substrate, and a sealing layer composed by curing a composition having a viscosity of 100Pa · s or less and a thixotropy (thixotropy) index of 1.1 or less and mechanically bonding the semiconductor device and the substrate by filling a gap therebetween, wherein the sealing material is mainly composed of a resin binder and a filler, and the polyepoxide, an acid anhydride, and a rheology modifier are essential components as the resin binder (see, for example, patent document 1). According to the mounted body disclosed in patent document 1, a mounted body of a semiconductor device can be realized which has high reliability and productivity while improving the fluidity of a sealing material used for flip chip (flip chip) mounting using a conductive adhesive.

Disclosure of Invention

Problems to be solved by the invention

However, in the mounted body described in patent document 1, the sealing material is configured by using a resin binder and a filler, and the sealing material is hard because the resin binder is composed of a polyepoxide, an acid anhydride, and a rheology modifier as essential components. As a result, when an external force is applied to the mounted body described in patent document 1, for example, when an external force is applied to bend the substrate, there may be a case where a defect such as damage to the sealing material or disconnection of the electrical connection between the semiconductor device and the conductive adhesive occurs.

Accordingly, an object of the present invention is to provide a mounted body that can ensure reliability of electrical connection between an element and a conductive member electrically connected to the element even when an external force such as to bend a substrate is applied.

Means for solving the problems

In order to achieve the above object, the present invention provides a mounting body including:

an insulating base material;

an element mounted on the insulating base material with the conductive member interposed therebetween; and

and a covering portion that covers at least a part of the side surface of the conductive member and at least a part of the side surface of the element, and covers at least a part of a boundary between the conductive member and the element, the covering portion being provided so as to be in contact with the surface of the insulating base material, and the covering portion having an elastic modulus of 0.1MPa or more and 500MPa or less.

In the above-described mounted body, the insulating base material preferably has flexibility, and the covering portion preferably deforms in response to an external force.

In the above-described mounted body, the insulating base material is preferably a flexible substrate, and the conductive member is preferably a low-temperature curable conductive paste.

In the above-described mounted body, the covering portion is configured by using a curable composition, and the curable composition preferably has a viscosity of 10Pa · s or more and 100Pa · s or less before curing.

In order to achieve the above object, the present invention provides an electronic device including the mounting body according to any one of the above aspects.

In order to achieve the above object, the present invention provides a curable composition for a coating portion of a mounting body, the mounting body including:

an insulating base material;

an element mounted on the insulating base material with the conductive member interposed therebetween; and

a coating portion, the coating portion

Covering at least a part of the side surface of the conductive member and the side surface of the element, and covering at least a part of a region including a boundary between the conductive member and the element, the covering portion being provided so as to be in contact with the surface of the insulating base material;

the curable composition has an elastic modulus of 0.1MPa or more and 500MPa or less after curing.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the mounted body of the present invention, it is possible to provide a mounted body which can ensure reliability of electrical connection between a component and a conductive member electrically connected to the component even when an external force such as to bend a substrate is applied.

Drawings

Fig. 1 is a schematic cross-sectional view of a mounting body according to an embodiment of the present invention.

FIG. 2 is a schematic view of a test piece.

FIG. 3 is a schematic diagram of the test method.

Fig. 4 is a graph showing a change in resistance.

Detailed Description

< brief summary of mounting body >

When a device (device) such as a semiconductor element is mounted on an insulating base material using solder, the solder is provided on the surface of the insulating base material, and the device is mounted on the solder and then heated and cured (reflow step). Then, the solder melted at the contact portion between the element and the solder is widened (fillet), and not only the portion where the element and the solder are in contact but also a part of the side surface of the element is adhered to the solder. As a result, the element and the insulating base material are strongly bonded.

On the other hand, for example, when a flexible substrate and/or a flexible substrate is used as the insulating substrate, a solder that requires a reflow step at a high temperature cannot be used, and thus a low-temperature-curing conductive paste is used as the conductive member. Further, when a device is mounted on an insulating substrate using a conductive member such as a low-temperature-curable conductive paste, no rounded corner is formed unlike solder. Therefore, only the portion of the device in contact with the solder is bonded, and the side surface of the device is not substantially bonded to the low-temperature curable conductive paste. As a result, when an external force is applied to the insulating substrate so as to bend the insulating substrate, a part of the bonding region between the element and the low-temperature curable conductive paste may be peeled off, and thus the electrical connectivity may be deteriorated. In the present embodiment, "low temperature" means a temperature of about 100 ℃.

Accordingly, the inventors of the present invention have made various studies from the viewpoint of maintaining reliability of electrical connectivity between an element and a conductive member even when a flexible base material, which is a base material made of a material that easily stretches and/or buckles, is used and/or when a low-temperature curing conductive adhesive is used, and as a result, have found that electrical connectivity between an element and a conductive member can be maintained well even when the base material is stretched and/or buckled by covering at least a part of a side surface of the conductive member and a side surface of the element with a curable composition (adhesive resin) having a predetermined elastic modulus and covering at least a part of a boundary between the conductive member and the element and bringing the adhesive resin into contact with a surface of an insulating base material.

That is, the mounting body according to the embodiment of the present invention includes the following members: an insulating base material; an element mounted on the insulating base material with the conductive member interposed therebetween; and a covering portion that covers at least a part of the side surface of the conductive member and the side surface of the element, and covers at least a part of a boundary (that is, a "boundary-including region" or a "boundary end portion") between the conductive member and the element, the covering portion being provided so as to be in contact with the surface of the insulating base material, and having an elastic modulus that can deform the shape of the insulating base material in accordance with expansion and contraction and/or flexure of the insulating base material. The covering portion is formed by using an adhesive resin. Here, the elastic modulus is, for example, a storage modulus in a dynamic viscoelasticity measurement at a frequency of 1 Hz.

< details of the mounting body >

Fig. 1 shows an outline of a cross section of a mounting body according to an embodiment of the present invention. Specifically, (a) of fig. 1 shows an outline of a cross section of the mounting body 1 according to the present embodiment, and (b) and (c) of fig. 1 show an outline of a cross section of a modification of the mounting body, respectively. Fig. 1 is a schematic diagram, and the dimensions and the dimensional ratios of the respective components are not limited to those shown in the drawings.

As shown in fig. 1 (a), the mounting body 1 includes: an insulating base material 10; a device 20, wherein the device 20 is mounted on the surface 10a of the insulating base material 10 via the conductive member 30; and a covering portion 40 that covers at least a part of an end portion of a boundary 50 formed at a contact portion between the element 20 and the conductive member 30, covers a region including at least a part of a side surface 22a of the element 20 (and/or a side surface of an electrode 22 described later) and at least a part of a side surface 30a of the conductive member 30, and is adhered to a part of the surface 10a of the insulating base material 10.

The covering portion 42 covers substantially the entire side surfaces of the element 20 and the conductive member 30 in the mounting body 1a according to the modification example of fig. 1 (b), and has substantially the same configuration and function as the mounting body 1 except that it covers substantially the entire side surfaces. In the mounting body 1b according to another modification example of fig. 1 (c), the covering portion 44 covers substantially the entire surfaces of the side surfaces and the upper surface of the element 20 and the side surfaces of the conductive member 30, and has substantially the same configuration and function as the mounting body 1 except that this configuration and function is substantially the same. Therefore, the mounting body 1a and the mounting body 1b are not described in detail except for the points different from the mounting body 1.

[ insulating base Material 10, element 20]

The insulating substrate 10 is a substrate having insulating properties (insulating substrate). As a material constituting the insulating base 10, various materials such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polymethyl methacrylate (PMMA), polyimide, polypropylene (PP), polyurethane, and various rubbers can be used. The insulating base material 10 may have flexibility, or may be a flexible substrate. The insulating base material 10 is preferably formed of a material having flexibility, and is also preferably a flexible substrate, from the viewpoint of enabling stretching and/or bending. Since the insulating base material 10 formed using polyimide has heat resistance, solder can be used as the conductive member 30. On the other hand, in the insulating substrate 10 formed using PET or the like, when solder is used as the conductive member 30, the insulating substrate 10 is damaged in a mounting stage (reflow process or the like), and thus the solder cannot be used as the conductive member 30, and a low-temperature curing conductive paste is used.

Examples of the element 20 include electronic components such as a semiconductor element (including a light emitting element such as a light emitting diode and a laser diode, a light receiving element, a solar cell, and other sensors), a chip component (chip component), and a discrete component (discrete component). In addition, 1 or more elements 20 may be mounted on the insulating base 10. The element 20 is configured to have electrodes 22 at the ends thereof, for example (for example, one electrode 22 is an electrode for a positive electrode, and the other electrode 22 is an electrode for a negative electrode). The electrode 22 and the conductive member 30 are bonded to each other to electrically connect the two, thereby bonding and fixing the element 20 to the insulating base 10. Therefore, the boundary 50 is also generated at the contact portion of the electrode 22 of the element 20 and the conductive member 30. A predetermined conductive pattern (not shown in fig. 1) is provided in advance on the surface 10a of the insulating base 10. A conductive member 30 is electrically connected to a portion on the conductive pattern.

[ conductive Member 30]

The conductive member 30 is a curable composition having conductivity, and is preferably a low-temperature curable conductive paste. As a material of the low-temperature curing conductive paste, a compound which cures at a low temperature (about 100 ℃ or lower) is preferable, and various compounds can be used, and a compound having flexibility is more preferable. Further, as for the conductive member 30, from the viewpoint of reliability of maintaining electrical connectivity with the element 20 even when deformation such as expansion and/or buckling is applied to the mounted body 1, the storage modulus at 23 ℃ in the dynamic viscoelasticity measurement at 1Hz preferably has an elastic modulus of 0.1MPa to 100 MPa.

For example, as the material of the conductive member 30, epoxy-based compounds, rubber-based compounds such as SBR, NBR, IR, BR, and CR, acrylic compounds, polyester-based compounds, polyamide-based compounds, polyether-based compounds, polyurethane-based compounds, polyimide-based compounds, silicone resin-based compounds, and the like can be used. As the conductive substance contained in the conductive member 30, various conductive materials can be used. As the conductive material, for example, a noble metal powder such as silver, gold, or palladium, a base metal powder such as nickel or copper, an alloy powder such as silver palladium, or a composite powder such as a silver-plated copper powder, and further, a non-metal powder having conductivity such as carbon, or the like can be used. These conductive materials may be used alone or in combination of 2 or more. The particle size and shape of these conductive materials are not particularly limited.

The conductive curable composition may also be a conductive curable composition containing (a) an elastomer component having a storage modulus at 23 ℃ in the dynamic viscoelasticity measurement at 1Hz in the range of 0.1MPa to 100MPa, and (B) a conductive filler, wherein the conductive filler is 50 mass% or more and 85 mass% or less of the total content. From the viewpoint of ensuring the flexibility of the cured product, (B) the conductive filler is 50 mass% or more and 85 mass% or less of the total content, and (B) the conductive filler may contain (B1) the first silver powder and the silver plating powder, and (B2) the second silver powder and the silver plating powder. Further, from the viewpoint of ensuring more satisfactory flexibility of the cured product, (b1) the tap densities (tap density) of the first silver powder and the silver plating powder were 2.5g/cm³Above and 6.0g/cm³Hereinafter, (b2) the tap densities of the second silver powder and silver plating powder were 1.0g/cm³Above and 3.0g/cm³Hereinafter, the mixing ratio of (b1) and (b2 [ (b1)/(b2)]The ratio by mass may be 1/10 or more and 10/1 or less. The conductive curable composition may further contain (C) silica (silica) subjected to a hydrophobic property-imparting treatment with a predetermined surface-treating agent.

(A) an elastomer component having a storage modulus at 23 ℃ in a dynamic viscoelasticity measurement at 1Hz in the range of 0.1MPa to 100 MPa)

(A) The elastomer components are: an elastomer component having a storage modulus at 23 ℃ in the range of 0.1MPa to 100MPa in a dynamic viscoelasticity measurement at 1 Hz. A cured product which is flexible and has excellent stretchability can be obtained by setting the storage modulus at 23 ℃ in the range of 0.1MPa to 100MPa in the dynamic viscoelasticity measurement at 1 Hz. Further, it is particularly preferable that the storage modulus at 23 ℃ is in the range of 0.1MPa to 50MPa in the dynamic viscoelasticity measurement at 1Hz, since the fracture is less likely to occur when the cured product is expanded or contracted.

The dynamic viscoelasticity of the elastomer component (a) can be measured, for example, by the following means.

When the conductive curable composition is an aqueous dispersion, the dynamic viscoelasticity can be measured for a cured product obtained by removing (B) a conductive filler and/or (C) a solid component such as silica by filtration and then evaporating the dispersion medium by heating at 100 ℃. In the case where the conductive curable composition is dispersed in an organic solvent (diluent), the dynamic viscoelasticity can be measured for a cured product obtained by removing (B) a conductive filler and/or (C) a solid component such as silica by filtration and then evaporating the dispersion medium by heating at 150 ℃.

When a resin that is liquid at ordinary temperature, such as a modified silicone resin-based resin and/or a urethane resin, is used in the conductive curable composition, the elastomer component (a) may be extracted by removing solid components such as (B) the conductive filler and/or (C) silica by filtration, curing may be performed by adding a curing catalyst as needed, and the dynamic viscoelasticity may be measured with respect to the obtained cured product.

A cured product of the conductive curable composition can be subjected to dynamic viscoelasticity measurement on the obtained cured product by immersing the cured product in a solvent capable of dissolving the cured product and shaking the solvent to remove solid components such as (B) the conductive filler and/or (C) silica and extract (a) the elastomer component, and then removing the solvent by heating at 150 ℃.

As the elastomer component having a storage modulus at 23 ℃ in the dynamic viscoelasticity measurement at 1Hz in the range of 0.1MPa to 100MPa, conventionally known resins and/or rubbers can be used, and examples thereof include materials made of thermoplastic resins and/or thermosetting resins, crosslinked rubbers, and vulcanized rubbers. Examples of such resins include vinyl resins and/or acrylic resins, butadiene resins, silicone resins, polyurethane resins, modified silicone resins, and the like. In addition, the above-mentioned resins may also be used in the form of an aqueous dispersion.

For example, as the vinyl resin, a vinyl acetate polymer resin, a vinyl chloride-vinyl acetate copolymer resin, a vinyl chloride-vinyl acetate-maleic acid terpolymer resin, or a combination thereof is cited.

Further, as the acrylic elastomer as the acrylic resin, for example, a glass transition temperature (T) of polybutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate and the like are mentioned_g) A relatively low resin, or a combination thereof. Further, a block copolymer containing poly (methyl (meth) acrylate) in addition to the above skeleton is preferable from the viewpoint that flexibility can be maintained and the elongation properties and/or adhesiveness can be secured.

Various block copolymers can be used as the block copolymer. For example, an acrylic triblock copolymer produced by a living polymerization method can be used. Specifically, block copolymers such as a polymethyl methacrylate-polybutadiene-polystyrene copolymer, a polymethyl methacrylate-polybutyl acrylate-polymethyl methacrylate copolymer, a copolymer obtained by subjecting these copolymers to carboxylic acid modification treatment or hydrophilic group modification treatment, a polymethyl methacrylate-polybutyl acrylate copolymer, and a polymethyl methacrylate-polybutyl acrylate-polymethyl methacrylate copolymer can be used.

Examples of the butadiene-based resin include an SB (styrene-butadiene) resin, an SBs (styrene-butadiene-styrene) resin, an SEBS resin (styrene-ethylene/butylene-styrene), an SIS (styrene-isoprene-styrene) resin, an SIBS (styrene-isoprene/butadiene-styrene) resin, an SEPS (styrene-ethylene/propylene-styrene) resin, and the like, or a combination thereof.

As the modified silicone resin, any conventionally known organic polymer containing a crosslinkable silicon group can be used. The crosslinkable silicon group of the crosslinkable silicon group-containing organic polymer is: a group having a hydroxyl group or a hydrolyzable group bonded to a silicon atom and crosslinkable by forming a siloxane bond.

((B) conductive Filler)

The conductive filler is formed by using a material having electrical conductivity. Examples of the conductive filler include metal powders such as silver powder, copper powder, nickel powder, aluminum powder, silver-plated powders thereof, silver-coated glass, silver-coated silica, and silver-coated plastics; zinc oxide, titanium oxide, ITO, ATO, carbon black, and the like. The conductive filler is preferably silver powder or silver plating powder from the viewpoint of reducing volume resistivity (volume resistivity), and silver powder and silver plating powder are more preferably used in combination from the viewpoint of reliability of conductivity and cost.

The shape of the conductive filler (B) can be various shapes (for example, granular shape, spherical shape, oval shape, cylindrical shape, flake shape, flat plate shape, or pellet shape). The conductive filler may also be slightly roughened or may have a jagged surface. The conductive filler can be used in a curable composition having conductivity by combining the particle shape, size, and/or hardness of the conductive filler. In addition, for the purpose of further improving the conductivity of the cured product of the conductive curable composition, a plurality of types of conductive fillers (B) having different particle shapes, sizes, and/or hardnesses from each other may be combined. The number of the conductive fillers to be combined is not limited to 2, and may be 3 or more. Among them, a flake-like conductive filler and a granular conductive filler are preferably used in combination.

Here, the flake shape includes a shape such as a flat shape, a flake shape, or a scale shape, and includes a shape obtained by pressing (squarh) silver powder having a three-dimensional shape such as a spherical shape and/or a block shape in one direction. The granular state indicates the shape of the entire conductive filler that does not have a flake form. For example, as the granular form, there are listed: the powder is aggregated into a house shape of grapes, spherical, substantially spherical, massive, dendritic, or a mixture of silver powders having these shapes.

When silver powder or silver plating powder is used as the (B) conductive filler, the conductive filler can be produced by various methods. For example, when a flake-like silver powder is used as the conductive filler, the silver powder can be produced by mechanically pulverizing a silver powder such as a spherical silver powder, a lump silver powder, and/or a granular silver powder using a jet mill (jet mill), a roll mill, or a ball mill. When the silver powder in a granular form is used as the conductive filler, it can be produced by an electrolytic method, a pulverization method, a heat treatment method, an atomization method, a reduction method, or the like. Among them, the reduction method is preferable because a powder having a small tap density can be easily obtained by controlling the reduction method.

As the silver powder and silver plating powder used for the conductive filler (B), known silver powder and silver plating powder can be widely used. In addition, the silver powder and the silver plating powder preferably include (b1) a first silver powder and a silver plating powder and (b2) a second silver powder and a silver plating powder, respectively, each having a predetermined tap density. The mixing ratio of (b1) and (b2 [ (b1)/(b2) ] is 1/10 or more and 10/1 or less, preferably 1/4 or more and 4/1 or less, and more preferably 3/2 or more and 4/1 or less in terms of mass ratio. In the component (b1), the mixing ratio of the first silver powder and the silver plating powder is 1/10 or more and 10/1 or less, and in the component (b2), the mixing ratio of the second silver powder and the silver plating powder is 1/10 or more and 10/1 or less.

(b1) The tap densities of the first silver powder and the silver-plated powder were 2.5g/cm³Above and 6.0g/cm³Hereinafter, it is preferably 3.0g/cm³Above and 5.0g/cm³The following. The 50% average particle diameter of the (b1) first silver powder is preferably 0.5 to 15 μm. The shapes of the (b1) first silver powder and silver plating powder may be various, and various shapes such as flake and granule shapes may be used. Among these, flake-like silver powder and silver-plated powder are preferable.

The tap densities of the silver powder and the silver plating powder can be measured by a method in accordance with the tap method (tap method) of 20.2 according to JIS K5101-1991. The 50% average particle diameter is a particle diameter at 50% of the volume accumulation measured by a laser diffraction scattering particle size distribution measurement method.

(b2) The tap densities of the second silver powder and the silver-plated powder were 1.0g/cm³Above and 3.0g/cm³The following. The 50% average particle diameter of the (b2) second silver powder and silver plating powder is preferably 0.5 to 20 μm. The shapes of the (b2) second silver powder and silver plating powder may be various, and various shapes such as flake and granule shapes may be used. In particular, granular silver powder and silver plating powder are preferable.

(B) The content of the conductive filler is 50 mass% or more and 85 mass% or less, preferably 65 mass% or more and 85 mass% or less, and more preferably 70 mass% or more and 80 mass% or less of the total content of the conductive curable composition. The content is preferably 50 mass% or more from the viewpoint of obtaining sufficient conductivity, and is preferably 85 mass% or less from the viewpoint of ensuring excellent conductivity, adhesiveness, and workability. In particular, from the viewpoint of securing adhesiveness and workability, it is preferable that the content of the (b2) second silver powder and silver plating powder is not excessively increased.

When the tap densities of the component (b1) and the component (b2) are within the above ranges, sufficient conductivity can be exhibited without adding a large amount of silver powder or silver plating powder. From the viewpoint of cost reduction, it is particularly preferable to use a silver powder and/or silver plating powder in which one of the component (b1) and the component (b2) is in the form of a flake, and the other is in the form of a combination of a granular silver powder and/or silver plating powder.

((C) silica)

By using (C) 1 or more types of silica selected from the group consisting of hydrophobic silica and hydrophilic silica obtained by hydrophobic treatment with a specific surface treatment agent together with the component (a) and the component (B), a conductive curable composition having particularly excellent stability of conductivity can be obtained. (C) The particle size of the silica is not particularly limited, but is preferably a fine silica powder, more preferably a fine silica powder having an average particle size of 7nm or more and 16nm or less, and most preferably a fine silica powder having an average particle size of 7nm or more and 14nm or less.

As the hydrophilic silica, known hydrophilic silica can be widely used, and among them, fumed silica (fumed silica) having silanol groups (Si — OH groups) on the surface is preferable. By using hydrophilic silica, it is possible to ensure fluidity and prevent bleeding without increasing viscosity. The electrically conductive curable composition having fluidity is suitable for applications requiring fluidity, for example, applications in which it is applied to a substrate by screen printing and patterned as a thin film of about 50 μm.

As the hydrophobic silica, hydrophobic silica obtained by hydrophobizing with 1 or more surface-treating agents selected from the group consisting of dimethyldichlorosilane, hexamethyldisilazane, (meth) acryloylsilane, octylsilane (e.g., trimethoxyoctylsilane, etc.), and aminosilane is used. By using the hydrophobic silica obtained by the hydrophobic treatment with such a specific surface treatment agent, bleeding can be prevented while ensuring ejection properties and/or shape retention. The conductive curable composition having shape retention properties is suitably used for applications requiring shape retention properties, for example, applications requiring a film thickness of 100 μm or more when a pattern is formed by applying the composition to a substrate by screen printing, and applications in which a connection portion obtained by using solder is replaced by a conductive curable composition.

The hydrophobization treatment method of silica using a surface treatment agent can be selected from known methods, and examples thereof include a method of spraying the surface treatment agent described above to untreated silica, or a method of mixing vaporized surface treatment agents and performing heat treatment. The hydrophobization is preferably carried out in a dry process under a nitrogen atmosphere.

(C) The blending ratio of the component (a) is not particularly limited, but is preferably 3 parts by mass or more and 20 parts by mass or less, more preferably 5 parts by mass or more and 10 parts by mass or less, with respect to 100 parts by mass of the component (a). (C) The silica may be used alone or in combination of 2 or more.

(other additives)

In the conductive curable composition, a curing catalyst, a filler, a plasticizer, an adhesion imparting agent, a stabilizer, a colorant, a physical property adjusting agent, a thixotropic agent, a dehydrating agent (storage stability improving agent), an adhesion imparting agent, a sagging preventing agent, an ultraviolet absorber, an antioxidant, a flame retardant, a substance such as a radical polymerization initiator, and/or various solvents such as toluene and/or alcohol may be blended as necessary from the viewpoint of adjusting viscosity and/or physical properties without impairing the functions such as conductivity and/or curability of the conductive curable composition. In addition, other polymers that are compatible may also be blended.

The curable composition having conductivity may be a one-pack type or a two-pack type, as required. The curable composition having conductivity is particularly suitable for use in the form of one-pack type. Further, since the curable composition having conductivity is cured at room temperature by moisture in the atmosphere, it is suitably used in the form of a room temperature moisture curable conductive adhesive. In addition, in terms of the effect of the curable composition having conductivity, curing can be accelerated by heating (for example, heating at about 80 to 100 ℃) as appropriate.

The curable composition having conductivity can be cured by coating or printing on a substrate, has high conductivity, and is used instead of solder. The curable composition having conductivity is suitably used for bonding and/or mounting of electronic components such as a semiconductor chip device and a discrete device, circuit connection, adhesion and fixation of a crystal oscillator and/or a piezoelectric device, sealing (sealing) of a package, and the like. By using the curable composition having conductivity, a circuit obtained by bonding 1 or 2 or more kinds of electronic components such as a semiconductor element, a chip component, and a discrete component can be formed on the surface of the substrate.

Further, since the cured product of the curable composition having conductivity constituting the conductive member 30 according to the present embodiment has flexibility, when the insulating substrate 10 is provided with a predetermined pattern on the surface thereof, even if deformation such as stretching and/or buckling is applied to the insulating substrate 10, the cured product is freely deformed in accordance with the deformation.

[ covering part 40]

The covering portion 40 is provided by being adhered to at least a part of the side surface of the element 20 and at least a part of the side surface of the conductive member 30, and also adhered to the surface 10a of the insulating base material 10. The coating 40 functions as a pseudo round corner, but has no conductivity. Therefore, the following characteristics are required for the coating portion 40: a) good adhesion to electrically conductive member 30, b) the material constituting covering 40 does not penetrate into electrically conductive member 30 (if penetration occurs, the resistance value of electrically conductive member 30 may increase), c) the strain or the like between element 20 and electrically conductive member 30 can be relieved even when an external force such as expansion and/or flexion is applied to mounted body 1.

The covering portion 40 has an elastic modulus of 0.1MPa or more, and preferably 1MPa or more, and more preferably 5MPa or more, from the viewpoint of ensuring appropriate flexibility and ensuring reliability of electrical connectivity. The covering portion 40 has an elastic modulus of 500MPa or less, preferably 200MPa or less, and more preferably 100MPa or less, from the viewpoint of reducing strain generated in the mounted body 1 when an external force is applied to the mounted body 1 and maintaining durability (reduced conductivity due to a change with time). The covering portion 40 has the above elastic modulus and is deformable by an external force. The elastic modulus is a storage modulus in a dynamic viscoelasticity measurement at a frequency of 1 Hz.

As the curable composition (also referred to as "adhesive resin" in the present embodiment) constituting the covering portion 40, various compounds can be used in consideration of adhesiveness, heat resistance, and barrier properties against moisture, oxygen, and the like. For example, the covering portion 40 may be formed using various thermosetting adhesives, photocurable adhesives, or curable adhesives such as two-component mixed curable adhesives, in addition to silicone resin (silicone resin), acrylic resin, methacrylic resin, or the like. Before the covering portion 40 is formed (i.e., before the curable composition is cured), the curable composition preferably has a viscosity of 10Pa · s or more and 100Pa · s or less from the viewpoint of preventing spreading more than necessary when it is dropped onto the insulating base material 10. In addition, when the covering portion 40 is formed, the curable composition may be cured in advance into a sheet shape and used. The sheet-like covering 40 can be molded by a known method.

[ method for producing mounting body 1 ]

As an example, the mounted body 1 can be manufactured through the following steps. First, an insulating base material 10 having a surface 10a provided with a predetermined conductive pattern in advance is prepared (insulating base material preparation step). Next, a conductive curable composition constituting the conductive member 30 is applied or printed on the region on the conductive pattern where the element 20 is mounted and at a position where the electrode 22 of the element 20 should be arranged (printing step). Next, the device 20 is mounted on the conductive curable composition (mounting step). Then, the curable composition is cured at normal temperature (e.g., 23 ℃) or low temperature (e.g., 100 ℃ or lower) (curing step). Thereby, the element 20 is fixed on the insulating base material 10.

Next, a curable composition constituting the covering portion 40 is applied to at least a part of the region around the element 20, and the curable composition is cured at normal temperature or low temperature. In this case, the amount of the curable composition applied is adjusted to the amount that covers the boundary 50 between the covering element 20 and the conductive member 30 and covers the side surface of the conductive member 30. Thereby, the covering 40 is formed (covering forming step). Through the above steps, the mounted body 1 is manufactured.

In the mounting body 1a, the coating amount of the curable composition is adjusted to an amount that can coat substantially all of the side surfaces of the element 20 and the conductive member 30 in the coating portion forming step. Similarly, in the mounting body 1b, in the coating portion forming step, the amount of the curable composition to be applied is adjusted to an amount that covers the entire element 20.

The mounting body 1 is applicable to various electronic devices such as a printed circuit (printed electronics) and/or a wearable device (wearable device), a robot (robot), and an electronic device including a machine having a movable domain.

< effects of the embodiment >

In the mounting body 1 according to the present embodiment, the region including the boundary 50 between the element 20 and the conductive member 30 is covered with the covering portion 40 having a predetermined elastic modulus, and the covering portion 40 is also bonded to the surface 10a of the insulating base material 10. Therefore, not only when the insulating base material 10 is flexed but also when it is expanded or contracted, the stress of the covering portion 40 due to the flexure and/or expansion or contraction is relaxed, and therefore the electrical connectivity between the element 20 and the conductive member 30 can be maintained. As a result, according to the mounting body 1, the reliability of the electrical connectivity between the element 20 and the conductive member 30 can be maintained.

The reliability of the electrical connectivity is equivalent to the case where the low-temperature curing conductive paste is used when the solder is used for the conductive member 30 when the mounted body 1 is bent. On the other hand, when the mounted body 1 is expanded and contracted, the reliability is superior in the case of using the low-temperature curable conductive paste as compared with the case of using the solder. This is because the low-temperature-curable conductive paste expands and contracts due to the force of expansion and contraction, but the solder does not expand and contract.

In particular, when a flexible substrate is used as the insulating base material 10, since a circuit can be formed on the flexible substrate by printing, it is easy to adjust the resistance value in the circuit and to reduce the number of components. Further, although the important member such as the IC is "hard", since the covering portion 40 is provided in a portion where such a "hard" electronic member is provided, the reliability (reliability of electrical connectivity, operational reliability, and the like) of the entire package 1 can be improved.