JPH0992031A - Conductive composition and soldered structure using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductive composition that has high deflection adhesive strength and a good solder wettability by using binder components, consisting of a resol type phenol resin and an alkoxyalkyl compound, and metal particles of specific sizes as its main components. SOLUTION: A polymer type conductive composition of high reliability which is wetted with solder in a wide temperature range is obtained whose main components are 3 to 40wt.% binder components, consisting of a resol type phenol resin having a dimethylene-ether bond and an alkoxyalkyl compound, and 60 to 97% metal particles with an average grain size of 0.1 to 50μm. The alkoxyalkyl compound is a compound represented by formula 1 or 2 wherein (p) and (q) are 1 to 3, R is an alkyl group, R' is an alkyl group, an alkoxy group, a carboxylate group, a sulfonate group, or a phosphate group, R''' is an ethylene group, and X is Si, Ti, Al, or Zr, and is preferably 0.5 to 10% of the binder components. The binder components preferably contain 0.5 to 30% linear macromolecular resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive composition used as a wiring material, an electrode material, and a conductive bonding material for electronic parts and circuits, and a solder-bonded structure using the same.

[0002]

2. Description of the Related Art In recent electronic parts and circuits, polymer type conductive compositions have been used as wiring materials, electrode materials and conductive bonding materials in various forms mainly for the purpose of cost reduction of conductive materials. However, polymer-type conductive compositions have a limit in increasing conductivity, and electronic components and circuits are not ready for solder mounting in the end, so polymer-type conductive compositions can get wet with solder. Functions are required.
In addition, since the mainstream of the substrate material is a resin substrate such as glass epoxy or polyimide, a high-strength material that does not break even when the substrate is bent is required for the conductive composition.

Usually, the polymer-type conductive composition is a paste and solidifies by drying or baking to become a conductive material. After solidification, as shown in FIG.
2 is covered and dispersed.

In the usual polymer type conductive composition, the binder resin 22 is often a thermosetting resin. In this case, the binder resin film covering the metal particles 21 is strong and repels the solder without breaking it, thus soldering. There is a problem that does not get wet. On the other hand, when the binder resin is composed of a thermoplastic resin such as a linear polymer resin, there is a problem that the binder resin is melted by the heat of the solder and the dispersed metal particles fall off. Further, the metal particles in the conductive composition have a high specific surface area, and the surface of the particles is oxidized even in a normal environment, so that the solder is not wet.

In order to improve such problems, the use of organic metal (JP-A-1-34597) and the use of Ag-coated Cu powder (JP-A-63-81706) prevent oxidation of metal particles. Proposals have been made to improve solder wetting. In these known examples, a resol type phenol resin, which is one of thermosetting resins, is used as a binder component. In this resin, part of the molecular bond (dimethylene ether bond) is decomposed and desorbed by the action of the flux and the heat of the solder, so the resin film covering the metal particles is broken and the unoxidized metal particles are exposed and the solder Get wet (see (a) to (c) of FIG. 5). FIG. 5 is a schematic sectional view showing a solder wetting mechanism of a conductive composition containing such a conventional resol-type phenol resin as a binder component. In FIG. 5A, 31 is a metal particle and 32 is a binder resin. When the flux and heat are applied in the state of FIG. 5A, the binder resin portion of the surface layer is thermally decomposed to become an altered binder resin layer 33 (FIG. 5B), which has low strength. Next, when the solder 34 is applied on the altered binder resin layer 33, the strength of the altered binder resin layer 33 is lowered as shown in FIG.

Therefore, in the known example, the solder wettability is high,
Moreover, a conductive composition having a high flexural adhesion strength of the coating film and a solder-attached structure using the same could not be obtained.

[0007]

As described above, the conventional examples proposed in JP-A-1-34597 and JP-A-63-81706 are all binder components in the conductive composition. Is very small (content ratio: approx. 10
wt% or less), the flexible adhesion strength of the coating film when the conductive composition was applied to the substrate was low, and there was a limit to the application. Particularly, in the conventional example, this tendency was remarkable because a phenol resin that forms a hard and brittle coating film was used as the binder component.

Further, since the phenol resin secures the wetting of the solder by decomposing and desorbing a part of the molecular bond by heat, there is a problem that the strength is remarkably lowered after the solder is wet (see FIG. 5).

On the other hand, when the content ratio of the binder is increased (12 wt% or more) in order to increase the flexural adhesion strength of the coating film, the binder film coating the surface of the metal particles becomes thick and the decomposition and desorption become incomplete, so that the solder is not soldered. Wettability decreases. In addition, the soldering temperature is set to a high temperature (26
If the temperature is set to 0 ° C. or higher), the flexural adhesion strength of the coating film decreases.

Further, the conductive composition containing a resin binder and metal particles as main components has a large difference in specific gravity between the resin and the metal, so if it is stored for a long time in a paste state before curing, the metal particles will precipitate and it cannot be used. It may happen.

In order to solve the above-mentioned conventional problems, the present invention provides a highly reliable polymer-type conductive composition which has high flexural adhesion strength and wets solder in a wide temperature range, and further is stored for a long time in a paste state before curing. It is an object of the present invention to provide a polymer-type conductive composition having excellent stability in which metal particles are unlikely to precipitate and a solder-attached structure using the same.

[0012]

In order to achieve the above object, the conductive composition of the present invention comprises a resol-type phenol resin having a dimethylene ether bond and the chemical formula (Formula 1) or (Formula 2). A binder component comprising at least one alkoxyalkyl compound selected from compounds having a structure having an average particle size of 0.1 μm or more 5
It is characterized in that it contains metal particles of 0 μm or less as a main component.

In the conductive composition of the present invention, the binder component is 3 to 40% by weight and the metal particles are 60 to 97.
It is preferably in the weight%. Further, in the conductive composition of the present invention, the binder component is preferably a binder component further containing a linear polymer resin.

Further, in the conductive composition of the present invention, the content of the alkoxyalkyl compound in the binder component is preferably 0.5 to 10% by weight. Further, in the conductive composition of the present invention, the content of the linear polymer resin in the binder component is 0.5 to 30% by weight.
It is preferred that

In the conductive composition of the present invention, it is preferable that the metal particles include metal particles coated with at least one noble metal selected from Au, Ag, Pd and Pt.

In the conductive composition of the present invention, the metal particles are Ni, Cu, Al, Ti, Cr, Pb, Sn, Zn, I.
At least one metal selected from n and Bi or Ni and C
u, Al, Ti, Cr, Pb, Sn, Zn, In, Bi, Au, Ag, Pd, Pt
It is preferable to include metal particles having an alloy component of at least two selected from the group as a core and having a surface layer coated with at least one noble metal selected from Au, Ag, Pd, and Pt.

Further, the solder adhering structure of the present invention is a solder adhering structure having a solder layer on a surface layer of a conductive composition, wherein the conductive composition is a resol type phenol resin having a dimethylene ether bond. And a binder component comprising at least one alkoxyalkyl compound selected from the compounds having the structure represented by the chemical formula (Formula 1) or (Formula 2) described above, and having an average particle size of 0.1 μm or more and 50 μm or less. The metal particle component is a main component, and the metal particle component and the solder layer have a portion in direct contact with each other.

Further, in the solder-attached structure of the present invention, the binder component is 3 to 40% by weight, and the metal particles are 6%.
It is preferably from 0 to 97% by weight. Further, in the solder attachment structure of the present invention, the binder component is preferably a binder component further containing a linear polymer resin.

Further, in the solder-adhered structure of the present invention, the content of the alkoxyalkyl compound in the binder component is preferably 0.5 to 10% by weight. Further, in the solder attachment structure of the present invention, the content of the linear polymer resin in the binder component is preferably 0.5 to 30% by weight.

In the solder attachment structure of the present invention, it is preferable that the metal particles include metal particles coated with at least one noble metal selected from Au, Ag, Pd and Pt.

In the solder-adhered structure of the present invention, the metal particles are Ni, Cu, Al, Ti, Cr, Pb, Sn, Zn,
At least one metal selected from In and Bi or Ni and C
u, Al, Ti, Cr, Pb, Sn, Zn, In, Bi, Au, Ag, Pd, Pt
It is preferable to include metal particles having an alloy component of at least two selected from the group as a core and having a surface layer coated with at least one noble metal selected from Au, Ag, Pd, and Pt.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION According to the above-described solder attachment structure of the present invention, the conductive composition comprises a resol-type phenol resin having a dimethylene ether bond and the above-mentioned chemical formula (Formula 1) or (Formula 2). A binder component composed of at least one kind of alkoxyalkyl compound selected from compounds having a structure represented by and a metal particle component having an average particle diameter of 0.1 μm or more and 50 μm or less, and the metal particle component and solder. Since the layer has a portion that is in direct contact with the layer, a highly reliable polymer-type solder attachment structure that has high flexural strength and wets solder in a wide temperature range can be realized. And, the present invention, by using a resol-type phenolic resin having a dimethylene ether bond as a binder of the conductive composition, and an alkoxyalkyl compound, it is possible to wet the solder even in a low temperature range, and the flexural adhesion strength and the solder are high. It is possible to provide a conductive composition that has a small decrease in strength even after wetting and has improved storage stability in a paste state before curing.

The metal particles in the surface layer of the conductive composition coating film are partially coated with the resol type phenol resin and partially with the alkoxyalkyl compound. Further, some alkoxyalkyl compounds are also mixed in the resol type phenol resin. When flux and heat are applied here, the resol type phenolic resin on the surface of the coating film is easily decomposed to expose the metal particles, and the alkoxyalkyl compound coating layer coating the metal particles does not hinder solder wetting. ,
The metal particle component and the solder layer are in direct contact with each other.

Here, the resin composition of the resol type phenol resin and the alkoxyalkyl compound may be a modified product obtained by partially reacting or a simple mixture. The resol-type phenol resin and the alkoxyalkyl compound may be used each alone or as a mixture of two or more.

The resol type phenolic resin of the present invention has a dimethylene ether bond. More specifically, the benzene ring containing a phenol group and the benzene ring are bonded by a dimethylene ether [CH ₂ OCH ₂ ] bond.

The alkoxyalkyl compound may be of any type as long as it has the structure represented by the above chemical formula (Formula 1) or (Formula 2). In the above chemical formula, R has 1 to 3 carbon atoms. It is preferably a substituted or unsubstituted alkyl group. Further, as a substituted or unsubstituted alkyl group represented by R ′, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted carboxylic acid ester group, a substituted or unsubstituted sulfonic acid ester group, or a substituted or unsubstituted phosphoric acid ester group Are preferably those having 2 to 25 carbon atoms. As R "in the chemical formula (Formula 2), a substituted or unsubstituted ethylene group having 2 carbon atoms is preferable.

These alkoxyalkyl compounds are chemically combined with a phenol resin or a linear polymer such as a carboxylic acid group, a hydroxyl group, an amine group, a mercapto group, a vinyl group, an acryloyl group or an epoxy group in the molecule. It is particularly preferable that the functional group which may be bonded is contained in the molecular structure of R '.

Preferred specific examples of the alkoxyalkyl compound represented by the chemical formula (Formula 1) are, for example, γ
-Glycidoxypropyltrimethoxysilane, N- (β
-Aminoethyl) γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, vinyltriethoxysilane, vinyl-tris (β-methoxyethoxy) silane, γ-methacryloxypropyltrimethoxysilane, β- (3, 4-epoxycyclohexyl)
Ethyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, and isopropyltris (dioctylpyro) represented by the chemical formula (Formula 3). Phosphate)
Titanate,

[0029]

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Isopropyltriisostearoyl titanate represented by the chemical formula (Formula 4),

[0031]

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Isopropyltridodecylbenzenesulfonyl titanate represented by the chemical formula (Formula 5),

[0033]

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Isopropyl (N-amidoethylaminoethyl) titanate represented by the chemical formula (Formula 6),

[0035]

[Chemical 6]

Acetoalkoxyaluminum diisopropylate (trade name: "AL-M" manufactured by Kawaken Fine Chemical Co., Ltd.), isopropyl tris (dioctyl pyrophosphate) zirconate and the like can be mentioned.

As a preferred specific example of the alkoxyalkyl compound represented by the chemical formula (Formula 2), for example, bis (dioctylpyrophosphate) ethylene titanate represented by the chemical formula (Formula 7),

[0038]

[Chemical 7]

Bis (dioctylpyrophosphate) oxyacetate titanate represented by the chemical formula (Formula 8),

[0040]

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Dicumylphenyloxyacetate titanate represented by the chemical formula (Formula 9),

[0042]

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And the like. Here, in the —CH ₂ —CO— portion which is a part of the oxyacetate group of the compounds represented by the chemical formulas (Chemical formula 8) and (Chemical formula 9), R ″ in the chemical formula (Chemical formula 2) is a substituted ethylene group. Corresponding to the case of radicals,
This corresponds to a case where two hydrogen atoms bonded to one carbon atom of the ethylene group —CH ₂ —CH ₂ — are replaced with one oxygen atom.

As the binder component of the conductive composition of the present invention, it is also preferable to use a linear polymer resin in combination with the aim of further improving the flexural adhesion strength. The linear polymer resin may be of any type as long as it is basically compatible with the resol-type phenol resin, but as preferable examples, polyvinyl formal resin, polyvinyl butyral resin, polyester resin, polyamide resin, polyurethane resin, Polyurea resin, polyphenoxy resin, polyimide resin, poly (meth) acrylic ester resin, poly (meth) acrylamide resin, poly (meth) acrylonitrile resin, alkyd resin, silicone resin, acrylic rubber, nitrile rubber, chloroprene rubber, etc. To be The above-mentioned polymers can also be used as copolymers or modified products. For example, it is a polyether ester resin, a polyester urethane resin, a polyamide-imide resin or the like.

The content of the alkoxyalkyl compound in the binder component of the conductive composition of the present invention is preferably 0.5 to 10% by weight based on the total amount of the binder components, and in this range, metal particles fall off. There is no fear of becoming easy, the solder wettability is good even at a relatively low temperature, the solder wets over a wide temperature range, the flexural adhesion strength reduction of the coating film after the solder is wet is small, and the conductive composition of the present invention is not cured. It is preferable that the metal particles do not easily precipitate even when stored in the paste state for a long time.

When a linear polymer resin is used in combination in the conductive composition of the present invention, the content of the linear polymer resin in the binder component is based on the total amount of the binder components. It is preferably 0.5 to 30% by weight, more preferably 2 to 15% by weight. By using the linear polymer resin together in this range, there is no fear that the metal particles will easily fall off, and it is possible to further increase the bending strength of the coating film of the conductive composition of the present invention and the bending strength after solder wetting. It is possible and preferable.

As the binder of the conductive composition, in addition to the above-mentioned essential components, a third resin component is optionally added for the purpose of improving coating film strength, adhesion strength, conductivity, rheology adjustment and the like. Good.

As the metal particles of the conductive composition, any particles having an average particle size of 0.1 μm or more and 50 μm or less can be used, but as a preferred example, a noble metal selected from Au, Ag, Pd and Pt is used. It is desirable to use the above-mentioned metal particles as a main component. Here, the metal particles may be the noble metal-coated metal particles alone or a mixture thereof, and the noble metal-coated metal particles and Ni, Cu, Al, Ti, Cr, Pb, Sn, Zn, In, Bi,
It may be a mixture of any one of Au, Ag, Pd, and Pt, or a mixed metal particle of any combination of two or more kinds. Also Ni,
Cu, Al, Ti, Cr, Pb, Sn, Zn, In, Bi, Au, Ag, Pd, Pt
It is also possible to use a mixed powder of the alloy powder of any combination of two or more of the above and the precious metal-coated metal particles. And preferably, the metal particles are Ni, Cu, Al, Ti, Cr, Pb, Sn, Zn, I
At least one metal selected from n and Bi or Ni and C
u, Al, Ti, Cr, Pb, Sn, Zn, In, Bi, Au, Ag, Pd, Pt
It is preferable to include metal particles having an alloy component of at least two selected from the group as a core and having a surface layer coated with at least one noble metal selected from Au, Ag, Pd, and Pt.

By using these metal particles, it is possible to realize a conductive composition having excellent solder wettability even in a low temperature range and having a small decrease in strength even after solder wet. In the conductive composition of the present invention, the binder component and the metal particles are used in a proportion of 3 to 40% by weight for the binder component and 60 for the metal particles.
It is preferable that the content is from about 97% by weight because the conductive composition coating film has a high flexural strength and a highly reliable conductive composition wettable by solder in a wide temperature range can be realized. When the binder component is too large and the metal particles are too small, the flexural strength of the conductive composition coating film can be increased, but the solder wettability tends to decrease, and the binder component is too small and the metal particles are too small. If the amount is too large, the flexural strength of the conductive composition coating film tends to decrease.

As a constituent component of the conductive composition of the present invention, a rheology modifier such as a solvent, a dispersant or a leveling agent may be used, if necessary. In the present invention, since the alkoxy group of the alkoxyalkyl compound contained in the conductive composition binder is bonded to the metal particles during curing of the conductive composition coating film, a flexible conductive composition coating film having high flexural strength can be obtained. . Further, since the alkoxyalkyl compound is bonded to the base material to which the conductive composition is applied, a conductive composition coating film having high adhesion can be obtained.

The conductive composition of the present invention exposes metal particles by partly decomposing the resol-type phenol resin (dimethylene ether bond) in the binder, and the alkoxyalkyl compound does not inhibit solder wetting on the surface of the metal particles. It is characterized by forming a coating layer and wetting the solder. Therefore, the conductive composition of the present invention has better solder wettability than in the conventional case even in a low temperature range.

By the way, as described above, the conductive composition of the present invention is characterized in that a part (dimethylene ether bond) of the resol-type phenol resin in the binder is decomposed and released to expose the metal particles and wet the solder. Since the number is one, it is conceivable that the conductive composition coating film after solder wetting has a reduced flexing adhesion strength as in the conventional example. However, in the present invention, the alkoxy group of the alkoxyalkyl compound, which is a part of the binder, is chemically bonded to the hydroxyl group on the surface of the metal particles, and the alkyl group of the alkoxyalkyl compound is incorporated into the binder (especially when the alkyl group is an epoxy group or an epoxy group). In the case of a type that is reactively bonded to a phenol resin such as an amino group, it is possible to further reduce the decrease in flexural adhesion strength of the coating film after solder wetting.

FIG. 1 is a schematic sectional view showing a process of an embodiment for forming a solder-attached structure of the present invention. FIG. 1 (a)
In the above, 1 is metal particles, 2 is a binder component, and 3 is an alkoxyalkyl compound. In the state of FIG. 1A, the surface of the metal particle 1 is covered with the alkoxyalkyl compound 3 which is a part of the binder component 2. The binder component 2 is composed of a resole-type phenol resin having a dimethylene ether bond and an alkoxyalkyl compound. Therefore, the alkoxyalkyl compound is dispersed or compatible with the binder component 2. When a flux and heat are applied in the state of FIG. 1 (a), a part of the binder component 2 (resole type phenolic resin) in the surface layer of the conductive composition coating film is decomposed and desorbed to cover the metal covered with the alkoxyalkyl compound 3. The particles 1 are exposed ((b) of FIG. 1).
When the solder 4 is applied to the exposed metal particles 1, the solder adhering structure of the present invention having a high solder wettability and a high bending adhesion strength is obtained ((c) of FIG. 1). As described above, a resol-type phenol resin having a dimethylene ether bond and a binder component 2 composed of an alkoxyalkyl compound,
A coating film of a conductive composition containing metal particles 1 as a main component is formed on a substrate (not shown), and this is immersed in a solder solution to form solder 4 on the conductive composition coating film. At this time, the metal particles contained therein are exposed by the heat of the solder and the solder 4 gets wet. Since the metal particles 1 and the binder component 2 are strongly bound by the alkoxyalkyl compound, the conductive composition coating film is firmly bound to the solder layer.

Further, in the present invention, it is possible to further increase the flexural strength of the coating film and the flexural strength after solder wetting by adding a linear polymer resin to the binder.
FIG. 2 is a schematic cross-sectional view showing a process of an example of forming a solder attachment structure when a linear polymer resin is added to a binder in the present invention. In FIG. 2A, 1
Is a metal particle, 2 is a binder component composed of a resol type phenol resin, an alkoxyalkyl compound and a linear polymer resin, and 3 is an alkoxyalkyl compound. In the state of FIG. 2A, the surface of the metal particles 1 is the binder 2
Is covered with an alkoxyalkyl compound 3. When flux and heat are applied in the state of FIG. 2 (a),
A part of the binder component 2 in the surface layer of the conductive composition coating film, that is, the linear polymer resin is melted, and the resol-type phenol resin is decomposed and released to give an alkoxyalkyl compound 3
The metal particles 1 covered with are exposed ((b) of FIG. 2). When the solder 4 is applied to the exposed metal particles 1, the solder adhering structure of the present invention having a high solder wettability and a high bending adhesion strength is obtained ((c) of FIG. 2). As described above, the coating of the conductive composition of the present invention containing the binder component 2 composed of a resol-type phenol resin having a dimethylene ether bond, an alkoxyalkyl compound and a linear polymer resin, and the metal particles 1 as main components. A film is formed on a substrate, which is dipped in a solder liquid to form a solder 4 on the conductive composition coating film. At this time, the heat of the solder exposes the metal particles to be contained and wets the solder 4.
The metal particles and the binder component are strongly bound by the alkoxyalkyl compound, and when the solder cools, the linear polymer resin of the binder component that has melted also solidifies, so the conductive composition coating film is more firm with the solder layer. Bind to.

In addition, in the conductive composition of the present invention, since the surfaces of the metal particles are coated with the alkoxyalkyl compound, this acts as a kind of dispersant, and the paste state before curing is stored for a long time. Also has the function of suppressing the precipitation and aggregation of coexisting metal particles and can be stored for a long time.

Further, when metal particles having noble metals which are hard to oxidize and have high solder wettability on the surface are used as the metal particles, the resistance value is further stable and the solder wettability is high from low temperature region to high temperature region. It is preferable since it can be a conductive composition.

[0057]

The present invention will be described in more detail with reference to specific examples below, but the present invention is not limited to these examples.

Each composition formulation shown in Table 1 and Table 2
Each example was kneaded with this roll (Example 1 in all tables).
9 to 9 are abbreviated as 1 to 9. ) And a comparative example (Comparative Examples 1 to 5 are abbreviated as Ratio 1 to Ratio 5 in all the tables).

Coating films of these conductive compositions were formed on a glass epoxy substrate to a film thickness of 30 μm, and baked at 170 ° C. for 20 minutes. These conductive composition coating films were evaluated for solder wettability by the evaluation methods shown below, and the results are shown in Tables 3 and 4.

The solder wettability evaluation method is shown in FIG.
(E). In FIG. 3A, 11 is a glass epoxy substrate, 12 is a baked conductive composition coating film, and 13 is an intermediate body 13 in which the glass epoxy substrate 11 and the conductive composition coating film 12 are integrated. is there. This intermediate 13
For example, 100 conductive composition coating films 12 formed in a pattern of 1 × 1 mm ² are prepared. Next, as shown in FIG. 3B, the intermediate body 13 was immersed in the Sn—Pb eutectic solder bath 14 for 10 seconds. At this time, the temperature of the solder bath 14 was set at three levels (200 ° C., 220 ° C., 260 ° C.).
The obtained solder attachment structure is shown in FIG. Next, the number of wet solders 15 was measured. FIG. 3 (d) shows that the solder wettability is good, and FIG. 3 (e) shows that the solder wettability is poor. Reference numeral 16 is a portion having poor solder wettability.

The flexural adhesion strength was evaluated according to JIS-K6856. The method for evaluating the paste storability of the conductive composition is as follows.
It was put in a plastic container of c and placed in an environment of 25 ° C ± 3 ° C. The number of days elapsed until the metal particles in the paste were precipitated and a supernatant was produced was measured.

Evaluation results: In Examples 1 to 9, there was no problem in solder wettability from a low temperature. In addition, the bending adhesion strength is several tens.
With kg / cm ² It had a strength enough to withstand warpage and bending of the resin substrate. No precipitation occurred for more than 3 months.

Examples 4 to 7 are examples in which the kind and combination of the alkoxyalkyl compounds were changed, but the solder wettability was high and the flexure adhesion strength was also high. This indicates that the effect of the present invention can be obtained even if the kind of the alkoxyalkyl compound is changed.

Examples 8 and 9 are examples in which a linear polymer resin was added to the binder. When the alkoxyalkyl compound was contained, the solder wettability was good even at the low temperature range even when the linear polymer resin was added, and the flexure adhesion strength was much higher.

On the other hand, in Comparative Example 1, the solder wettability is sufficient, but the flexure adhesion strength is low (particularly the flexure adhesion strength after solder wetness is much lower), and it is suitable for mounting on a resin substrate that must withstand large flexure. Was not available. Precipitation also occurred after 70 days had passed. It is considered that the reason why the flexural adhesion strength is low is due to the brittleness of the phenol resin as the binder component. In addition, since the phenol resin is decomposed by the solder heat as described in FIG. 5, it is considered that the flexure adhesion strength after the solder is wet is further reduced.

Comparative Examples 2 and 3 are examples in which the ratio of the binder component of Comparative Example 1 is increased. Since the ratio of the binder component is high, the flexural adhesion strength is high, but the solder wettability is reduced (especially at low temperature), which is not practical. Comparative Example 2
In about 50 days, a precipitate occurs after about 50 days, and in Comparative Example 3, about 30 days after, a precipitate occurs. Comparative Example 2 is the same as Example 2,
Comparative Example 3 has the same binder component ratio as in Example 3, but the solder wettability and the storage stability are significantly different.
It is considered that the solder wettability does not deteriorate even if the ratio of the binder component is increased in Examples 2 and 3 because the alkoxyalkyl compound, which is an essential component of the present invention, makes the metal surface an environment in which the solder is easily wetted. To be

Comparative Example 4 is an example in which the flex adhesive strength is increased by using a tough epoxy resin without increasing the ratio of the binder component. The flex adhesive strength is high but the solder is not wet at all. This is because the epoxy resin that retains strength forms a solid coating film on the surface of the metal particles, so there is no phenomenon such as decomposition or melting of the binder even at high temperatures that wet the solder,
It is considered that this is because the metal particles contained therein are not exposed.

Comparative Example 5 is an example in which a linear polymer resin (polyamide resin) that is melted and softened by the heat of solder is used as a part of the binder. The flexural adhesion strength is high but the solder wettability at low temperature is low. A linear polymer resin that melts and softens is used as a binder component, and the linear polymer resin retains its original strong binding force when it is returned to room temperature after it has been wet with solder, and therefore it is possible to maintain high flexural adhesion strength. However, when the solder temperature is low, the melting and softening of the linear polymer resin becomes insufficient, so that the solder wettability is deteriorated. In Examples 8 and 9 in which the same linear polymer resin is used as a part of the binder component, there is no problem in the solder wettability at low temperature, because the dispersibility of the metal particles is high and the metal particles have high dispersibility. It is presumed that the binder film on the surface becomes thin and the metal particles are easily exposed even at a low temperature, or the alkoxide alkyl compound forms a layer on the surface of the metal particles that does not hinder solder wetting.

In Tables 1 to 4, resol type phenol resin: "PL43" manufactured by Gunei Chemical Co., Ltd.
48 "alkoxyalkyl compound A: γ-glycitoxypropyltrimethoxysilane alkoxyalkyl compound B: N- (β-aminoethyl) γ-aminopropyltrimethoxysilane alkoxyalkyl compound C: isopropyltris (dioctylpyrophosphate) titanate alkoxy Alkyl compound D: acetoalkoxyaluminum diisopropylate polyamide resin: "Daiamide 17" manufactured by Daicel
0 "Epoxy resin:" Epicoat 80 "manufactured by Yuka Shell Co., Ltd.
7 "and its curing agent dicyandiamide Further, the compounding composition of each component shown by numerical values in Tables 1 and 2 shows parts by weight.

[0070]

[Table 1]

[0071]

[Table 2]

[0072]

[Table 3]

[0073]

[Table 4]

[0074]

INDUSTRIAL APPLICABILITY The present invention provides a highly reliable polymer type conductive composition which has high flexural adhesion strength and wets solder in a wide temperature range, and metal particles even when stored in a paste state before curing for a long period of time. It is possible to provide a polymer-type conductive composition which is less likely to precipitate and has excellent stability, and a solder-attached structure using the same.

According to the present invention, since a conductive composition which can obtain a tough solder-adhered structure having a high bending adhesion strength and a small strength reduction even after solder wetting, a resin substrate liable to be warped or bent is obtained. Expansion of applications for mounting.
Further, since the solder gets wet from the low temperature range, the solder mounting conditions are widened. Further, distortion due to a difference in thermal expansion often occurs between the board and the mounted component, which causes destruction of the component, dropout, destruction of the conductive joint, or the like, but the conductive composition of the present invention is Since it also has an effect of relieving the strain, it is possible to prevent the components from being broken or dropped and the conductive joint from being broken by thermal strain.

In the present invention, base metal particles, which are the cheapest conductive metal particles and have excellent supply stability, are used as the core.
When metal particles coated with at least one noble metal selected from u, Ag, Pd, and Pt are used as the main component of the metal particles, the resistance value is stable and the solder wettability is high from low temperature to high temperature. It is possible to obtain a strong conductive composition, and since it uses only a small amount of expensive noble metal, it has excellent cost performance.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing a process of one embodiment of forming a solder attachment structure of the present invention.

FIG. 2 is a schematic cross-sectional view showing a process of one example of forming a solder attachment structure when a linear polymer resin is added to a part of a binder in the present invention.

3A to 3E are process diagrams showing a solder wettability evaluation method according to an embodiment of the present invention. (F) is a figure which shows the same solder erosion evaluation method.

FIG. 4 is a schematic sectional view of a conventional conductive composition.

FIG. 5 is a schematic cross-sectional view showing a solder wetting mechanism of a conventional conductive composition.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal particle 2 Binder component 3 Alkoxyalkyl compound 4 Solder 11 Glass epoxy substrate 12 Conductive composition coating film 13 Intermediate 14 Solder tank 15 Solder 16 Bad solder wettability part 21 Metal particle 22 Binder component 31 Metal particle 32 Binder resin 33 Deteriorated binder resin layer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical location H05K 1/09 H05K 1/09 D (72) Inventor Wataru Sakurai 1006 Kadoma, Kadoma, Osaka Prefecture Matsushita Denki Sangyo Co., Ltd.

Claims (14)

[Claims] 1. A resol type phenolic resin having a dimethylene ether bond and at least one compound selected from compounds having a structure represented by the following chemical formula (Formula 1) or (Formula 2) (hereinafter, alkoxyalkyl) Abbreviated as compound) Embedded image However, p = 1-3 integer, q = 1-3 integer R: substituted or unsubstituted alkyl group R ': substituted or unsubstituted alkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted carboxylic acid ester group , A substituted or unsubstituted sulfonic acid ester group, or a substituted or unsubstituted phosphoric acid ester group R ″: a substituted or unsubstituted ethylene group X: Si, Ti, Al, or Zr, and a binder component consisting of A conductive composition comprising a metal particle of 1 μm or more and 50 μm or less as a main component. 2. The conductive composition according to claim 1, wherein the binder component is 3 to 40% by weight and the metal particles are 60 to 97% by weight. 3. The conductive composition according to claim 1, wherein the binder component is a binder component further containing a linear polymer resin. 4. The content of the alkoxyalkyl compound in the binder component is 0.5 to 10% by weight.
The conductive composition according to any one of 3 above. 5. The conductive composition according to claim 3, wherein the content of the linear polymer resin in the binder component is 0.5 to 30% by weight. 6. The conductive composition according to claim 1, wherein the metal particles include metal particles coated with at least one noble metal selected from Au, Ag, Pd and Pt. 7. The metal particles are Ni, Cu, Al, Ti, Cr, Pb,
Sn, Zn, In, at least one metal selected from Bi or Ni, Cu, Al, Ti, Cr, Pb, Sn, Zn, In, Bi, Au, Ag,
A metal particle having an alloy component consisting of at least two selected from Pd and Pt as a core and having a surface layer coated with at least one noble metal selected from Au, Ag, Pd and Pt.
The conductive composition according to any one of claims 1 to 5. 8. A solder attachment structure having a solder layer on a surface layer of a conductive composition, wherein the conductive composition comprises a resol-type phenol resin having a dimethylene ether bond,
A binder component comprising at least one alkoxyalkyl compound selected from compounds having a structure represented by the chemical formula (Formula 1) or (Formula 2) according to claim 1, and an average particle diameter of 0.1 μm or more and 50 μm or less. And a solder layer having a portion in direct contact with the solder layer. 9. The solder adhering structure according to claim 8, wherein the binder component is 3 to 40% by weight and the metal particles are 60 to 97% by weight. 10. The solder attachment structure according to claim 8, wherein the binder component is a binder component further containing a linear polymer resin. 11. The content of the alkoxyalkyl compound in the binder component is 0.5 to 10% by weight.
10. The solder attachment structure according to any one of items 10 to 10. 12. The solder adhering structure according to claim 10, wherein the content of the linear polymer resin in the binder component is 0.5 to 30% by weight. 13. The solder adhering structure according to claim 8, wherein the metal particles include metal particles coated with at least one noble metal selected from Au, Ag, Pd, and Pt. 14. The metal particles are Ni, Cu, Al, Ti, Cr, P.
b, Sn, Zn, In, at least one metal selected from Bi or Ni, Cu, Al, Ti, Cr, Pb, Sn, Zn, In, Bi, Au,
A metal particle having an alloy component consisting of at least two selected from Ag, Pd, and Pt as a core and having a surface layer coated with at least one noble metal selected from Au, Ag, Pd, and Pt. The solder attachment structure described.