JP2023086762A - Conductive paste, cured product, sintering accelerator, and method for accelerating sintering - Google Patents

Abstract

To provide a conductive paste excellent in conductivity.SOLUTION: A conductive paste contains silver-containing particles and a sintering accelerator that accelerates sintering of the silver-containing particles. The sintering accelerator contains a compound represented by formula (1) or formula (2). In formula (1), m represents an integer from 1 to 20 inclusive. In formula (2), n represents an integer from 1 to 20 inclusive.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a conductive paste, a cured product, a sintering accelerator, and a sintering acceleration method.

An electronic component such as a semiconductor element is mounted on a substrate via an adhesive layer, for example. Such an adhesive layer may be required to have conductivity, and in such a case, the conductive adhesive layer may be formed from a resin composition containing silver-containing particles, for example.

A resin composition containing silver-containing particles, for example, may be used as a resin composition for producing a conductive paste. Techniques related to such resin compositions include, for example, those described in Patent Document 1. Patent Document 1 describes a thermosetting resin composition containing (A) plate-shaped fine silver particles, (B) silver powder having an average particle size of 0.5 to 30 μm, and (C) a thermosetting resin. In the thermosetting resin composition, electrical conductivity is exhibited by the formation of contact points between silver particles.

JP 2014-194013 A

However, in recent years, the level of conductivity required for conductive pastes has risen more than ever before, and conventional techniques have not been able to adequately meet such demands.

（式（１）中、ｍは１以上２０以下の整数である。）

（式（２）中、ｎは１以上２０以下の整数である。）
［２］
上記［１］に記載の導電性ペーストであって、
前記シンタリング促進剤が式（１）で示される化合物を含み、式（１）中、ｍは１以上１１以下の整数である、導電性ペースト。
［３］
上記［１］または［２］に記載の導電性ペーストであって、
前記シンタリング促進剤が式（２）で示される化合物を含み、式（２）中、ｎは２以上１３以下の整数である、導電性ペースト。
［４］
上記［１］～［３］のいずれかに記載の導電性ペーストであって、
前記銀含有粒子が球状粒子、鱗片状粒子、凝集状粒子、および多面体形状の粒子からなる群から選択される１種または２種以上を含む、導電性ペースト。
［５］
上記［４］に記載の導電性ペーストであって、
前記銀含有粒子が球状粒子、鱗片状粒子、凝集状粒子、および多面体形状の粒子からなる群から選択される２種以上を含む、導電性ペースト。
［６］
上記［１］～［５］のいずれかに記載の導電性ペーストであって、
エポキシモノマーをさらに含む、導電性ペースト。
［７］
上記［６］に記載の導電性ペーストであって、
フェノール系硬化剤をさらに含む、導電性ペースト。
［８］
上記［６］または［７］に記載の導電性ペーストであって、
イミダゾール系硬化促進剤をさらに含む、導電性ペースト。
［９］
上記［１］～［８］のいずれかに記載の導電性ペーストであって、
（メタ）アクリルモノマーをさらに含む、導電性ペースト。
［１０］
上記［９］に記載の導電性ペーストであって、
ラジカル重合開始剤をさらに含む、導電性ペースト。
［１１］
上記［１］～［１０］のいずれかに記載の導電性ペーストであって、
溶剤をさらに含む、導電性ペースト。
［１２］
上記［１］～［１１］のいずれかに記載の導電性ペーストであって、
当該導電性ペーストを、焼結処理後の厚みが０．０５ｍｍになるようにガラス板上に塗布し、窒素雰囲気下で、３０℃から２００℃まで６０分間かけて昇温し、続けて２００℃で１２０分間焼結処理し、硬化物を得た場合の、当該硬化物の体積抵抗率が４．０μΩ・ｃｍ以上９．５μΩ・ｃｍ以下である、導電性ペースト。
［１３］
上記［１］～［１２］のいずれかに記載の導電性ペーストを焼結して得られる硬化物。
［１４］
銀含有粒子同士がシンタリングすることを促進するシンタリング促進剤であって、
式（１）または式（２）で示される化合物を含む、シンタリング促進剤。

（式（１）中、ｍは１以上２０以下の整数である。）

（式（２）中、ｎは１以上２０以下の整数である。）
［１５］
上記［１４］に記載のシンタリング促進剤を用いて銀含有粒子のシンタリングを促進する、シンタリング促進方法。 According to the present invention, the following conductive paste, cured product, sintering accelerator, and sintering acceleration method are provided.
[1]
silver-containing particles;
a sintering accelerator that promotes sintering between the silver-containing particles;
A conductive paste containing
A conductive paste, wherein the sintering accelerator contains a compound represented by formula (1) or (2).

(In formula (1), m is an integer of 1 or more and 20 or less.)

(In formula (2), n is an integer of 1 or more and 20 or less.)
[2]
The conductive paste according to [1] above,
A conductive paste, wherein the sintering accelerator contains a compound represented by formula (1), wherein m is an integer of 1 or more and 11 or less.
[3]
The conductive paste according to [1] or [2] above,
A conductive paste, wherein the sintering accelerator contains a compound represented by formula (2), wherein n is an integer of 2 or more and 13 or less.
[4]
The conductive paste according to any one of [1] to [3] above,
A conductive paste, wherein the silver-containing particles include one or more selected from the group consisting of spherical particles, scale-like particles, aggregated particles, and polyhedral particles.
[5]
The conductive paste according to [4] above,
A conductive paste, wherein the silver-containing particles include two or more selected from the group consisting of spherical particles, scale-like particles, aggregated particles, and polyhedral particles.
[6]
The conductive paste according to any one of [1] to [5] above,
A conductive paste further comprising an epoxy monomer.
[7]
The conductive paste according to [6] above,
A conductive paste further comprising a phenolic hardener.
[8]
The conductive paste according to [6] or [7] above,
An electrically conductive paste, further comprising an imidazole curing accelerator.
[9]
The conductive paste according to any one of [1] to [8] above,
An electrically conductive paste further comprising a (meth)acrylic monomer.
[10]
The conductive paste according to [9] above,
A conductive paste, further comprising a radical polymerization initiator.
[11]
The conductive paste according to any one of [1] to [10] above,
A conductive paste further comprising a solvent.
[12]
The conductive paste according to any one of [1] to [11] above,
The conductive paste was applied to a glass plate so that the thickness after sintering was 0.05 mm, and the temperature was raised from 30°C to 200°C over 60 minutes in a nitrogen atmosphere, and then to 200°C. is sintered for 120 minutes to obtain a cured product having a volume resistivity of 4.0 μΩ·cm or more and 9.5 μΩ·cm or less.
[13]
A cured product obtained by sintering the conductive paste according to any one of [1] to [12] above.
[14]
A sintering accelerator that promotes sintering between silver-containing particles,
A sintering accelerator containing a compound represented by formula (1) or (2).

(In formula (1), m is an integer of 1 or more and 20 or less.)

(In formula (2), n is an integer of 1 or more and 20 or less.)
[15]
A method for promoting sintering, comprising promoting sintering of silver-containing particles using the sintering accelerator described in [14] above.

ADVANTAGE OF THE INVENTION According to this invention, the electrically conductive paste excellent in electroconductivity is provided.

1 is a cross-sectional view showing a semiconductor device in which an adhesive layer is formed using the conductive paste of this embodiment; FIG. 4 is an SEM observation image of a cross section of a cured product formed from the conductive paste of Example 2. FIG. 4 is an SEM observation image of a cross section of a cured product formed from the conductive paste of Comparative Example 1. FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. In addition, in all the drawings, the same constituent elements are denoted by the same reference numerals, and the description thereof will be omitted as appropriate. In addition, "a to b" means "a or more and b or less" unless otherwise specified.

[Conductive paste]
<Overview of sintering technology>
The conductive paste according to this embodiment is a sintering type conductive paste. First, an outline of the sintering technology will be explained.

In the sintering type conductive paste, conductivity is ensured by sintering metal particles in the sintering process. That is, the interface between the metal particles disappears due to the action of heat, the metal particles are sintered with each other, and a sintering structure (metal particle connection structure) is formed. The sintered structure thus formed functions as a conductive path.

The sintering-type conductive paste usually contains a resin component as a binder. The full sintering type is one in which the resin component completely volatilizes in the sintering process and no resin component remains in the cured product. On the other hand, when only a part of the resin component volatilizes in the sintering process and the resin component remains in the cured product, it is called a half-sintering type.

In the half-sintering type conductive paste, the resin component remaining in the cured product acts to adhere the sintering structure (metal particle connecting structure) to the adherend.

An outline of formation of an adhesive layer using a sintering-type conductive paste will be described with reference to FIG.

FIG. 1 is a cross-sectional view showing a semiconductor device 100 in which an adhesive layer is formed using the conductive paste of this embodiment.
In the semiconductor device 100 , the adhesive layer 10 is formed by applying the conductive paste according to the present embodiment to the surface of the substrate 30 . Next, the semiconductor element 20 is mounted on the surface of the substrate 30 with the adhesive layer 10 interposed therebetween.

After the semiconductor element 20 is mounted via the adhesive layer 10, the silver-containing particles contained in the adhesive layer 10 are sintered by sintering.

After that, the semiconductor element 20 and the substrate 30 are electrically connected by bonding wires 40 and sealed with a mold resin 50. Then, a plurality of solders are applied to the back surface of the substrate 30 opposite to the surface on which the semiconductor element 20 is mounted. The semiconductor device 100 is formed by forming the balls 60 .

式（１）中、ｍは１以上２０以下の整数である。

式（２）中、ｎは１以上２０以下の整数である。 <Characteristics of the conductive paste according to the present embodiment>
The conductive paste according to this embodiment is
silver-containing particles;
a sintering accelerator that promotes sintering between the silver-containing particles;
A conductive paste containing
The sintering accelerator contains a compound represented by Formula (1) or Formula (2).

In formula (1), m is an integer of 1 or more and 20 or less.

In formula (2), n is an integer of 1 or more and 20 or less.

The adhesive layer formed from the conductive paste of this embodiment has good conductivity.

When the cross section of the cured product formed from the conductive paste of the present embodiment is observed with an SEM, it can be confirmed that more silver-containing particles are fused together and sintering is promoted. It is believed that the promotion of sintering in this way improves electrical conductivity and thermal conductivity.

<Each component>
Each component contained in the conductive paste of the present embodiment will be described below.

(sintering accelerator)
A sintering accelerator is an agent that accelerates sintering of metal particles.

Since the conductive paste of the present embodiment contains a sintering accelerator, sintering of silver-containing particles is promoted as compared with a conductive paste that does not contain a sintering accelerator. It is considered that the promotion of sintering in this manner improves electrical conductivity and thermal conductivity.

Conventionally, in the field of conductive pastes, an agent that promotes sintering of metal particles in this way has not been found. The present inventors have found an agent that does this, and have completed the present invention.

Although the mechanism by which the sintering accelerator of the present embodiment promotes sintering is not clear, the dispersibility of the silver-containing particles is enhanced by the sintering accelerator of the present embodiment acting on the surface of the silver-containing particles. As a result of the improvement, it is presumed that fusion and mass transfer at the contact interface between the silver-containing particles are promoted, and sintering is promoted.

式（１）中、ｍは１以上２０以下の整数である。

式（２）中、ｎは１以上２０以下の整数である。 The sintering accelerator according to this embodiment can contain one or more compounds represented by formula (1) or formula (2).

In formula (1), m is an integer of 1 or more and 20 or less.

In formula (2), n is an integer of 1 or more and 20 or less.

The sintering accelerator according to this embodiment is characterized by having an ethylene glycol structure or a propylene glycol structure. The inventors speculate that these structures interact with the surfaces of the silver-containing fine particles to improve the dispersibility of the silver-containing fine particles.

In the above formula (1), m is an integer of 1 or more, preferably 2 or more, more preferably 3 or more, still more preferably 4 or more, and 20 or less, preferably 11 or less, more preferably is an integer of 10 or less, more preferably 9 or less.
When m is within the above range, the dispersibility of the silver-containing particles is further improved, and the electrical conductivity and thermal conductivity of the adhesive layer formed from the conductive paste are further improved.
In the above formula (2), n is an integer of 1 or more, preferably 2 or more, more preferably 3 or more, still more preferably 4 or more, and 20 or less, preferably 13 or less, more preferably is 12 or less, more preferably 11 or less.
When n is within the above range, the dispersibility of the silver-containing particles is further improved, and the electrical conductivity and thermal conductivity of the adhesive layer formed from the conductive paste are further improved.

Specific examples of the sintering accelerator according to the present embodiment include:
Kyoeisha Chemical Co., Ltd. Epolite 40E (ethylene glycol diglycidyl ether), Epolite 100E (diethylene glycol diglycidyl ether), Epolite 400E (polyethylene glycol diglycidyl ether), Epolite 70P (polypropylene glycol diglycidyl ether), Epolite 200P (tripropylene) glycol diglycidyl ether), Epolite 400P (polypropylene glycol diglycidyl ether);
Nagase ChemteX Co., Ltd. Denacol EX-810 (ethylene glycol diglycidyl ether), Denacol EX-821 (polyethylene glycol diglycidyl ether), Denacol EX-830 (polyethylene glycol diglycidyl ether), Denacol EX-920 (polypropylene glycol) diglycidyl ether), Denacol EX-931 (polypropylene glycol diglycidyl ether), and the like.

The conductive paste of the present embodiment may contain only one type of sintering accelerator, or may contain two or more types.

The content of the sintering accelerator in the conductive paste of the present embodiment is preferably 0.5 parts by mass or more, more preferably 0.7 parts by mass or more when the conductive paste is 100 parts by mass. and more preferably 1.0 parts by mass or more. This further promotes sintering of the silver-containing particles.

In addition, the content of the sintering accelerator in the conductive paste of the present embodiment is preferably 50 parts by mass or less, more preferably 20 parts by mass or less, when the conductive paste is 100 parts by mass. It is preferably 10 parts by mass or less. As a result, the balance of properties such as heat cycle resistance and adhesion to adherends is improved.

(Silver-containing particles)
The conductive paste according to this embodiment contains silver-containing particles.

The silver-containing particles are sintered by an appropriate heat treatment in the sintering process to form a particle connecting structure (sintering structure).

The silver-containing particles according to this embodiment are not particularly limited in shape.

The silver-containing particles according to this embodiment preferably contain one or more selected from the group consisting of spherical particles, scale-like particles, aggregated particles, and polyhedral particles.

In the present embodiment, it is more preferable to contain two or more kinds of silver-containing particles selected from spherical particles, scaly particles, aggregated particles, and polyhedral particles. , agglomerate, and polyhedral-shaped silver-containing particles b2, and more preferably spherical silver-containing particles b1 and scale-like silver-containing particles b2-1. preferable. As a result, the contact ratio between the silver-containing particles is further improved, so that a network is easily formed after sintering the conductive paste, and thermal conductivity and electrical conductivity are further improved.

By including the silver-containing particles b2 in the silver-containing particles, it is possible to suppress resin cracks in the molded product obtained from the conductive paste and to suppress an increase in the coefficient of linear expansion.
In the present embodiment, the term “spherical” is not limited to a perfect sphere, and includes a shape with some irregularities on the surface. Its circularity is, for example, 0.90 or more, preferably 0.92 or more, and more preferably 0.94 or more.

The median diameter _D50 of the silver-containing particles is, for example, 0.01 μm or more and 50 μm or less, preferably 0.1 μm or more and 20 μm or less, more preferably 0.5 μm or more and 10 μm or less. By setting the median diameter _D50 to an appropriate value, it is easy to balance thermal conductivity, sinterability, resistance to heat cycles, and the like. Also, by setting the _D50 to an appropriate value, it may be possible to improve the workability of application/adhesion.
The particle size distribution (horizontal axis: particle size, vertical axis: frequency) of the silver-containing particles may be unimodal or multimodal.

From the viewpoint of the effect of the present invention, the silver-containing particles preferably include spherical silver-containing particles b1 and scale-like silver-containing particles b2-1. These silver-containing particles are more preferably silver particles consisting essentially of silver.

The median diameter D ₅₀ of the spherical silver-containing particles b1 is, for example, 0.1 to 20 μm, preferably 0.5 to 10 μm, more preferably 0.5 to 5.0 μm.
The specific surface area of the spherical silver-containing particles b1 is, for example, 0.1 to 2.5 m ² /g, preferably 0.5 to 2.3 m ² /g, more preferably 0.8 to 2.0 m ² /g. be.
The tap density of the spherical silver-containing particles b1 is, for example, 1.5 to 6.0 g/cm ³ , preferably 2.5 to 5.8 g/cm ³ , more preferably 4.5 to 5.5 g/cm ³ . be.
The circularity of the spherical silver-containing particles b1 is, for example, 0.90 or more, preferably 0.92 or more, and more preferably 0.94 or more.
Satisfying each of these properties provides an excellent balance of thermal conductivity, sinterability, resistance to heat cycles, and the like.

The median diameter _D50 of the scale-like silver-containing particles b2-1 is, for example, 0.1 to 20 μm, preferably 1.0 to 15 μm, more preferably 2.0 to 10 μm.
The specific surface area of the scale-like silver-containing particles b2-1 is, for example, 0.1 to 2.5 m ² /g, preferably 0.2 to 2.0 m ² /g, more preferably 0.25 to 1.2 m ² /g.
The tap density of the scale-like silver-containing particles b2-1 is, for example, 1.5 to 6.0 g/cm ³ , preferably 2.5 to 5.9 g/cm ³ , more preferably 4.0 to 5.8 g/cm 3 . ^cm3 .
Satisfying each of these properties provides an excellent balance of thermal conductivity, sinterability, resistance to heat cycles, and the like.

In the present embodiment, by combining spherical silver-containing particles b1 that satisfy at least one of the above characteristics and scaly silver-containing particles b2-1 that satisfy at least one of the above characteristics, thermal conductivity and electrical conductivity especially improved.

The ratio of the content of the spherical silver-containing particles b1 to the content of the scale-like silver-containing particles b2-1 (b1/b2-1) is preferably 0.1 or more and 10 or less, more preferably 0.3 or more and 5 or less. , particularly preferably 0.5 or more and 3 or less. As a result, the contact ratio between the silver-containing particles is particularly improved, so that a network is easily formed after sintering the conductive paste, and the thermal conductivity and electrical conductivity are particularly improved.

The ratio (b1/b2-1) of the median diameter _D50 of the spherical silver-containing particles b1 to the median diameter _D50 of the scale-like silver-containing particles b2-1 is preferably 0.01 or more and 0.8 or less, more preferably It is 0.05 or more and 0.6 or less.
As a result, the voids between the scale-like silver-containing particles are efficiently filled with the spherical silver-containing particles, and the contact ratio between the silver-containing particles is particularly improved. Therefore, after sintering the conductive paste, the network is easily formed, and thermal conductivity and electrical conductivity are particularly improved.

The ratio of the tap density of the spherical silver-containing particles b1 to the tap density of the scale-like silver-containing particles b2-1 (b1/b2-1) is preferably 0.5 or more and 2.0 or less, more preferably 0.7 or more. 1.2 or less.
As a result, the filling rate of the silver-containing particles is improved, and the contact rate between the silver-containing particles is particularly improved, so that a network is easily formed after sintering the conductive paste, and thermal conductivity and electrical conductivity are improved. especially improve.

The median diameter _D50 of the silver-containing particles can be obtained by, for example, particle image measurement using a flow type particle image analyzer FPIA (registered trademark)-3000 manufactured by Sysmex Corporation. More specifically, the particle diameter of the silver-containing particles can be determined by measuring the volume-based median diameter in a wet manner using this apparatus.

The content of the silver-containing particles in the conductive paste according to the present embodiment is preferably 40 parts by mass or more, more preferably 60 parts by mass or more, when the total non-volatile components of the conductive paste are 100 parts by mass. and more preferably 80 parts by mass or more. Thereby, electrical conductivity and thermal conductivity can be further improved.

In addition, the content of the silver-containing particles in the conductive paste according to the present embodiment is preferably 98 parts by mass or less, more preferably 97 parts by mass, when the total non-volatile components of the conductive paste are 100 parts by mass. parts or less, more preferably 96 parts by mass or less. This results in an excellent balance of thermal conductivity, sinterability, adhesion to adherends, resistance to heat cycles, and the like.

The silver-containing particles may be (i) particles consisting essentially of silver, or (ii) particles consisting of silver and a component other than silver. Moreover, (i) and (ii) may be used together as the metal-containing particles.

(i) Particles consisting essentially of silver include, for example, silver particles.

(ii) Particles composed of silver and components other than silver include, for example, silver-coated resin particles. Silver-coated resin particles are particles in which the surfaces of resin particles are coated with silver. Silver-coated resin particles whose surfaces are coated with silver have good thermal conductivity and are softer than particles made only of silver. It becomes easier to design the rate to an appropriate value.

In the silver-coated resin particles, it is sufficient that at least a part of the surface of the resin particles is covered with a silver layer. Of course, the entire surface of the resin particles may be covered with silver.

Specifically, in the silver-coated resin particles, the silver layer preferably covers 50% or more, more preferably 75% or more, and still more preferably 90% or more of the surface of the resin particles. Particularly preferably, in silver-coated resin particles, the silver layer covers substantially the entire surface of the resin particles.
From another point of view, when the silver-coated resin particles are cut along a certain cross section, it is preferable that the silver layer is observed all around the cross section.

As another aspect, the mass ratio of resin/silver in the silver-coated resin particles is, for example, 90/10 to 10/90, preferably 80/20 to 20/80, more preferably 70/30 to 30/70. be.

Examples of the "resin" in the silver-coated resin particles include silicone resins, (meth)acrylic resins, phenol resins, polystyrene resins, melamine resins, polyamide resins, polytetrafluoroethylene resins, and the like. Of course, resins other than these may be used. Moreover, only one resin may be used, or two or more resins may be used in combination.
From the viewpoint of elastic properties and heat resistance, the resin is preferably a silicone resin or a (meth)acrylic resin.

(i) Particles consisting essentially of silver can be obtained from, for example, DOWA Hi-Tech Co., Ltd., Fukuda Metal Foil & Powder Co., Ltd., and the like.

In addition, among the particles (ii) composed of silver and components other than silver, silver-coated resin particles can be obtained from, for example, Mitsubishi Materials Corporation, Sekisui Chemical Co., Ltd., Sanno Co., Ltd., and the like.

(other ingredients)
The conductive paste according to this embodiment may contain components other than the sintering accelerator and the silver-containing particles.

- Epoxy monomer The conductive paste according to the present embodiment preferably contains an epoxy monomer.

The epoxy monomer according to this embodiment has an epoxy group in its structure.

The epoxy monomer according to the present embodiment may be a monofunctional epoxy monomer having only one epoxy group in its structure, or a polyfunctional epoxy monomer having two or more epoxy groups in its structure. good.

Monofunctional epoxy monomers include, for example, 4-tert-butylphenyl glycidyl ether, m,p-cresyl glycidyl ether, phenyl glycidyl ether, cresyl glycidyl ether and the like.

Examples of polyfunctional epoxy monomers include bisphenol compounds such as bisphenol A, bisphenol F and biphenol, or derivatives thereof; hydrogenated bisphenol A, hydrogenated bisphenol F, hydrogenated biphenol, cyclohexanediol, cyclohexanedimethanol, cyclohexanediethanol diols having an alicyclic structure or derivatives thereof; aliphatic diols such as butanediol, hexanediol, octanediol, nonanediol, decanediol, or difunctional epoxidized derivatives thereof; trimethylolpropane skeleton, tri trifunctional ones having a hydroxyphenylmethane skeleton and aminophenol skeleton; polyfunctional ones obtained by epoxidizing phenol novolak resins, cresol novolak resins, phenol aralkyl resins, biphenyl aralkyl resins, naphthol aralkyl resins, and the like.

The content of the epoxy monomer in the conductive paste of the present embodiment is preferably 0.5 parts by mass or more, more preferably 0.7 parts by mass or more, when the conductive paste is 100 parts by mass. It is preferably 1.0 parts by mass or more. As a result, the balance of properties such as heat cycle resistance and adhesion to adherends is improved.

In addition, the content of the epoxy monomer in the conductive paste of the present embodiment is preferably 50 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 100 parts by mass of the conductive paste. is 10 parts by mass or less.

- (Meth)acrylic monomer The conductive paste according to the present embodiment preferably contains a (meth)acrylic monomer.

The acrylic monomer according to this embodiment is a monomer having a (meth)acrylic group in its structure.

The acrylic monomer according to the present embodiment may be a monofunctional acrylic monomer having only one (meth)acrylic group in its structure, or a polyfunctional acrylic monomer having two or more (meth)acrylic groups in its structure. It may be an acrylic monomer.

In this embodiment, the (meth)acrylic group is a concept including a (meth)acrylate group. Further, in the present embodiment, the (meth)acryl group is a concept representing an acryl group and a methacryl group, and the (meth)acryloyl group is a concept representing an acryloyl group and a methacryloyl group.

Examples of monofunctional acrylic monomers include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, and s-butyl (meth) acrylate. ) acrylate, t-butyl (meth)acrylate, butoxyethyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, heptyl (meth)acrylate, octylheptyl (meth)acrylate , nonyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, stearyl (meth)acrylate, behenyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate , aliphatic (meth)acrylates such as phenoxy polyethylene glycol (meth)acrylates;
Cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, 1,4-cyclohexanedimethanol mono (meth)acrylate, cyclopentyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, isobornyl ( Alicyclic (meth)acrylates such as meth)acrylate, 3-methyl-3-oxetanylmethyl (meth)acrylate, 1-adamantyl (meth)acrylate;
Phenyl (meth)acrylate, nonylphenyl (meth)acrylate, p-cumylphenyl (meth)acrylate, o-biphenyl (meth)acrylate, 1-naphthyl (meth)acrylate, 2-naphthyl (meth)acrylate, benzyl (meth)acrylate , 2-hydroxy-3-phenoxypropyl (meth)acrylate, 2-hydroxy-3-(o-phenylphenoxy)propyl (meth)acrylate, 2-hydroxy-3-(1-naphthoxy)propyl (meth)acrylate, 2 - aromatic (meth)acrylates such as hydroxy-3-(2-naphthoxy)propyl (meth)acrylate;
Heterocyclic (meth)acrylates such as 2-tetrahydrofurfuryl (meth)acrylate, N-(meth)acryloyloxyethylhexahydrophthalimide, 2-(meth)acryloyloxyethyl-N-carbazole, and the like can be mentioned. .

Examples of bifunctional acrylic monomers 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, 1,3-butanediol di (Meth)acrylates, 2-methyl-1,3-propanediol 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 aliphatic di(meth)acrylates such as acrylates, 1,10-decanediol di(meth)acrylates, glycerine di(meth)acrylates;
Alicyclic di(meth)acrylates such as cyclohexanedimethanol di(meth)acrylate, tricyclodecanedimethanol di(meth)acrylate, hydrogenated bisphenol A di(meth)acrylate, hydrogenated bisphenol F di(meth)acrylate ;
Aromatic di(meth)acrylates such as bisphenol A di(meth)acrylate, bisphenol F di(meth)acrylate, bisphenol AF di(meth)acrylate, ethoxylated bisphenol A di(meth)acrylate, fluorene type di(meth)acrylate acrylate;
Heterocyclic di(meth)acrylates such as isocyanuric acid di(meth)acrylate and the like can be mentioned.

Trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta( aliphatic (meth)acrylates such as meth)acrylates, dipentaerythritol hexa(meth)acrylate, ethoxylated glycerol tri(meth)acrylate;
Heterocyclic (meth)acrylates such as isocyanuric acid tri(meth)acrylate and the like can be mentioned.

The content of the (meth)acrylic monomer in the conductive paste of the present embodiment is preferably 0.3 parts by mass or more, more preferably 0.5 parts by mass, when the conductive paste is 100 parts by mass. Above, more preferably 0.6 parts by mass or more. As a result, the balance of properties such as heat cycle resistance and adhesion to adherends is improved.

In addition, the content of the (meth)acrylic monomer in the conductive paste of the present embodiment is preferably 50 parts by mass or less, more preferably 20 parts by mass or less, when the conductive paste is 100 parts by mass. More preferably, it is 10 parts by mass or less.

- Curing Agent When the conductive paste according to the present embodiment contains an epoxy monomer or an epoxy resin, the conductive paste according to the present embodiment preferably contains a curing agent. Thereby, the curing shrinkage of the epoxy monomer or the epoxy resin can be caused, and the silver-containing particles can be aggregated.

The content of the curing agent in the conductive paste of the present embodiment is preferably 0.5 parts by mass or more, more preferably 1.0 parts by mass or more, when the conductive paste is 100 parts by mass. It is preferably 1.2 parts by mass or more. As a result, the balance of properties such as heat cycle resistance and adhesion to adherends is improved.

In addition, the content of the curing agent in the conductive paste of the present embodiment is preferably 50 parts by mass or less, more preferably 20 parts by mass or less, even more preferably when the conductive paste is 100 parts by mass. is 10 parts by mass or less.

The conductive paste according to this embodiment preferably contains a phenol-based curing agent.

Phenolic curing agents include, for example, phenol novolak resins, cresol novolak resins, bisphenol novolak resins, phenol-biphenyl novolak resins and other novolak phenol resins; polyvinylphenol; polyfunctional phenol resins such as triphenylmethane phenol resins; modified phenol resins such as terpene-modified phenol resins and dicyclopentadiene-modified phenol resins; phenol aralkyl resins having a phenylene skeleton and/or biphenylene skeleton; phenol aralkyl-type phenol resins such as naphthol aralkyl resins having a phenylene and/or biphenylene skeleton; A, bisphenol compounds such as bisphenol F (dihydroxydiphenylmethane); and compounds having a biphenylene skeleton such as 4,4'-biphenol.

• Curing Accelerator The conductive paste according to the present embodiment may contain a curing accelerator that accelerates the reaction between the epoxy monomer or epoxy resin and the curing agent.

Curing accelerators include, for example, imidazole-based curing accelerators; organic phosphines, tetrasubstituted phosphonium compounds, phosphobetaine compounds, adducts of phosphine compounds and quinone compounds, adducts of phosphonium compounds and silane compounds containing phosphorus atoms, etc. Compounds; amidines and tertiary amines such as dicyandiamide, 1,8-diazabicyclo[5.4.0]undecene-7, and benzyldimethylamine; nitrogen atom-containing compounds such as quaternary ammonium salts of the above amidines or the above tertiary amines; can be mentioned.

The content of the curing accelerator in the conductive paste of the present embodiment is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, when the conductive paste is 100 parts by mass. More preferably, it is 0.07 parts by mass or more. As a result, the balance of properties such as heat cycle resistance and adhesion to adherends is improved.

Also, the content of the curing accelerator in the conductive paste of the present embodiment is preferably 10 parts by mass or less, more preferably 5 parts by mass or less when the conductive paste is 100 parts by mass.

The conductive paste according to this embodiment preferably contains an imidazole curing accelerator.

Examples of imidazole curing accelerators include 2-phenyl-1H-imidazole-4,5-dimethanol, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-methylimidazole, 2-phenylimidazole, 2 , 4-diamino-6-[2-methylimidazolyl-(1)]-ethyl-s-triazine, 2-undecylimidazole, 2-heptadecylimidazole, 2,4-diamino-6-[2-methylimidazolyl- (1)]-ethyl-s-triazine isocyanurate, 2-phenylimidazole isocyanurate, 2-methylimidazole isocyanurate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 1-cyanoethyl- 2-undecylimidazolium trimellitate and the like can be mentioned.

- Radical polymerization initiator When the conductive paste according to the present embodiment contains a (meth)acrylic monomer, the conductive paste according to the present embodiment preferably contains a radical polymerization initiator. As a result, the (meth)acrylic monomer can be cured and shrunk, and the silver-containing particles can be aggregated.

Examples of radical polymerization initiators that can be used include azo compounds and peroxides. Among the above specific examples, it is preferable to use, for example, a peroxide.

Examples of the peroxide include organic peroxides such as diacyl peroxide, dialkyl peroxide, and peroxyketal, and more specifically, ketone peroxides such as methyl ethyl ketone peroxide and cyclohexanone peroxide. peroxyketals such as 1,1-di(t-butylperoxy)cyclohexane and 2,2-di(4,4-di(t-butylperoxy)cyclohexyl)propane;
Hydroperoxides such as p-menthane hydroperoxide, diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, t-butyl hydroperoxide;
di(2-t-butylperoxyisopropyl)benzene, dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, t-butylcumyl peroxide, di-t- Dialkyl peroxides such as xyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3, di-t-butyl peroxide;
Diacyl peroxides such as dibenzoyl peroxide and di(4-methylbenzoyl) peroxide;
Peroxydicarbonates such as di-n-propyl peroxydicarbonate and diisopropyl peroxydicarbonate;
Peroxyesters such as 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, t-hexylperoxybenzoate, t-butylperoxybenzoate, t-butylperoxy 2-ethylhexanoate, etc. can be mentioned.

The content of the radical polymerization initiator in the conductive paste of the present embodiment is preferably 0.01 parts by mass or more, more preferably 0.03 parts by mass or more, when the conductive paste is 100 parts by mass. and more preferably 0.04 parts by mass or more. As a result, the balance of properties such as heat cycle resistance and adhesion to adherends is improved.

Further, the content of the radical polymerization initiator in the conductive paste of the present embodiment is preferably 10 parts by mass or less, more preferably 5 parts by mass or less when the conductive paste is 100 parts by mass. .

- Solvent The conductive paste according to the present embodiment preferably contains a solvent. This can improve the fluidity of the conductive paste and contribute to the improvement of workability.

Examples of the solvent according to the present embodiment include methyl carbitol, ethyl carbitol, butyl carbitol, methyl carbitol acetate, ethyl carbitol acetate, butyl carbitol acetate, acetylacetone, methyl isobutyl ketone (MIBK), anone, di Acetone alcohol, ethyl cellosolve, methyl cellosolve, butyl cellosolve, ethyl cellosolve acetate, methyl cellosolve acetate, butyl cellosolve acetate, ethyl alcohol, propyl alcohol, butyl alcohol, pentyl alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol, nonyl alcohol, decyl alcohol, ethylene Glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, methylmethoxybutanol, α-terpineol , β-terpineol, γ-terpineol, terpineol (mixture of α, β, γ), dihydroterpineol, hexylene glycol, benzyl alcohol, 2-phenylethyl alcohol, isopalmityl alcohol, isostearyl alcohol, lauryl alcohol, ethylene glycol , alcohols such as propylene glycol or glycerin;
Acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, diacetone alcohol (4-hydroxy-4-methyl-2-pentanone), 2-octanone, isophorone (3,5,5-trimethyl-2-cyclohexen-1-one) or Ketones such as diisobutyl ketone (2,6-dimethyl-4-heptanone);
Ethyl acetate, butyl acetate, diethyl phthalate, dibutyl phthalate, acetoxyethane, methyl butyrate, methyl hexanoate, methyl octanoate, methyl decanoate, methyl cellosolve acetate, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, 1,2- Esters such as diacetoxyethane, tributyl phosphate, tricresyl phosphate or tripentyl phosphate;
Tetrahydrofuran, dipropyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, propylene glycol dimethyl ether, ethoxyethyl ether, 1,2-bis(2-diethoxy)ethane or 1,2-bis(2-methoxyethoxy) ) ethers such as ethane;
ester ethers such as acetic acid 2-(2-butoxyethoxy)ethane;
Ether alcohols such as 2-(2-methoxyethoxy)ethanol, hydrocarbons such as toluene, xylene, n-paraffin, isoparaffin, dodecylbenzene, turpentine oil, kerosene or light oil;
Nitriles such as acetonitrile or propionitrile;
amides such as acetamide or N,N-dimethylformamide;
Examples include low-molecular-weight volatile silicone oils and volatile organically modified silicone oils.

The content of the solvent in the conductive paste of the present embodiment is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 3 parts by mass when the conductive paste is 100 parts by mass. Department or above.

In addition, the content of the solvent in the conductive paste of the present embodiment is preferably 50 parts by mass or less, more preferably 20 parts by mass or less, further preferably when the conductive paste is 100 parts by mass. It is 10 parts by mass or less.

In the conductive paste according to the present embodiment, if necessary, polymer components such as epoxy resins, (meth)acrylic resins, silicone resins, and butadiene rubbers; inorganic fillers such as silica and alumina; thixotropic adjustment such as fine silica; Coupling agents: antioxidants; dispersing agents; antifoaming agents; leveling agents and other components may also be added.
The content ratio of these components can be appropriately set according to the application of the conductive paste.

When the conductive paste of the present embodiment contains, for example, butadiene rubber among the above components, it preferably has an epoxy group from the viewpoint of the reactivity of other components.
The content of the butadiene rubber having an epoxy group (hereinafter referred to as epoxy group-containing butadiene rubber) in the conductive paste of the present embodiment reduces the storage elastic modulus of the effect obtained from the paste and improves the adhesion to the substrate or the like. From the viewpoint of improvement, when the conductive paste is 100 parts by mass, it is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and still more preferably 1.0 parts by mass or more, and It is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and even more preferably 30 parts by mass or less.
A specific example of the epoxy group-containing butadiene rubber is NISSO-PB JP-200 (epoxy-modified polybutadiene) manufactured by Nippon Soda Co., Ltd.

The conductive paste according to the present embodiment can be obtained by mixing the components described above and, if necessary, other components by a conventionally known method.

<Physical properties>
The conductive paste according to this embodiment is preferably pasty at 20°C. That is, the conductive paste according to the present embodiment can be preferably applied to a substrate or the like like glue at 20°C. As a result, the conductive paste of the present embodiment can be preferably used as an adhesive for semiconductor elements or the like.
Of course, depending on the applied process, the conductive paste of the present embodiment may be in the form of a relatively low viscosity varnish or the like.

The conductive paste according to this embodiment is applied to a glass plate so that the thickness after sintering is 0.05 mm, and the temperature is raised from 30 ° C. to 200 ° C. over 60 minutes in a nitrogen atmosphere. When a cured product is obtained by continuously sintering at 200° C. for 120 minutes, the volume resistivity of the cured product is preferably 9.5 μΩ·cm or less, more preferably 9.2 μΩ·cm or less. be. Thereby, the conductivity of the cured product obtained from the conductive paste of the present embodiment can be improved. Moreover, the volume resistivity of the cured product is usually 4.0 μΩ·cm or more, preferably 4.5 μΩ·cm or more.

<Application>
A semiconductor device can be manufactured using the conductive paste of the present embodiment. For example, a semiconductor device can be manufactured by using the conductive paste of the present embodiment as an "adhesive" between a substrate and a semiconductor element.

In other words, the semiconductor device of this embodiment includes, for example, a base material and a semiconductor element mounted on the base material via an adhesive layer obtained by sintering the conductive paste described above.

Examples of semiconductor devices include ICs, LSIs, power semiconductor devices (power semiconductors), and various other devices. Examples of substrates include various semiconductor wafers, lead frames, BGA substrates, mounting substrates, heat spreaders, and heat sinks.

An example of a semiconductor device will be described below with reference to the drawings.
FIG. 1 is a cross-sectional view showing an example of a semiconductor device.

In the semiconductor device 100 , the adhesive layer 10 is formed by applying the conductive paste according to the present embodiment to the surface of the substrate 30 . Next, the semiconductor element 20 is mounted on the surface of the substrate 30 with the adhesive layer 10 interposed therebetween.

The thickness of the adhesive layer 10 is preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 20 μm or more. Thereby, the conductive reliability of the adhesive layer is improved. Also, the thickness of the adhesive layer 10 is preferably 100 μm or less, more preferably 50 μm or less.

The method of applying the conductive paste is not particularly limited. Specifically, a dispensing method, a printing method, an inkjet method, and the like can be mentioned.

After the semiconductor element 20 is mounted via the adhesive layer 10, the silver-containing particles contained in the adhesive layer 10 are sintered by sintering.

After that, the semiconductor element 20 and the substrate 30 are electrically connected by bonding wires 40 and sealed with a mold resin 50. Then, a plurality of solders are applied to the back surface of the substrate 30 opposite to the surface on which the semiconductor element 20 is mounted. The semiconductor device 100 is formed by forming the balls 60 .

[Cured product]
The cured product according to this embodiment is obtained by sintering the conductive paste.

The sintering temperature is preferably 150° C. or higher, more preferably 180° C. or higher, and even more preferably 200° C. or higher. This can further promote sintering between the silver-containing particles.

The sintering temperature is preferably 300° C. or lower, more preferably 280° C. or lower, and even more preferably 250° C. or lower. This makes it easier to adjust the volatilization of the monomer components and the like during sintering, making it easier to adjust the physical properties of the cured product.

The volume resistivity of the cured product according to this embodiment is preferably 10.0 μΩ·cm or less, more preferably 9.5 μΩ·cm or less, and even more preferably 9.2 μΩ·cm or less. Thereby, the electroconductivity of hardened|cured material can be improved.
Moreover, the volume resistivity of the cured product according to the present embodiment is usually 4.0 μΩ·cm or more, preferably 4.5 μΩ·cm or more.

The storage elastic modulus (E') of the cured product according to the present embodiment is preferably 20 GPa or less, more preferably 17 GPa or less, and even more preferably 15 GPa or less. Thereby, the adhesion between the cured product and the adherend can be improved.
In addition, the storage elastic modulus (E') of the cured product according to this embodiment is preferably 1.0 GPa or higher, more preferably 3.0 GPa or higher, and even more preferably 5.0 GPa or higher. Thereby, the strength of the cured product can be improved.

As described above, the cured product according to the present embodiment is obtained by sintering a conductive paste containing a sintering accelerator. is promoted.

When the cross section of the cured product according to the present embodiment is observed with an SEM, it can be confirmed that more silver-containing particles are fused together and sintering is promoted. It is believed that the promotion of sintering in this way improves electrical conductivity and thermal conductivity.

式（１）中、ｍは１以上２０以下の整数である。

式（２）中、ｎは１以上２０以下の整数である。 [Sintering accelerator]
The sintering accelerator according to this embodiment promotes sintering between silver-containing particles, and includes a compound represented by formula (1) or formula (2).

In formula (1), m is an integer of 1 or more and 20 or less.

In formula (2), n is an integer of 1 or more and 20 or less.

Although the mechanism by which the sintering accelerator of the present embodiment promotes sintering is not clear, the dispersibility of the silver-containing particles is enhanced by the sintering accelerator of the present embodiment acting on the surface of the silver-containing particles. As a result of the improvement, it is presumed that fusion and mass transfer at the contact interface between the silver-containing particles are promoted, and sintering is promoted.

The sintering accelerator according to this embodiment can be blended in various resin compositions including conductive pastes.

The composition of the resin composition containing the sintering accelerator according to the present embodiment is not particularly limited.

The content of the sintering accelerator in the resin composition is not particularly limited. Above, more preferably 1.0 parts by mass or more. This further promotes sintering of the silver-containing particles.

In addition, the content of the sintering accelerator in the resin composition is preferably 50 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 100 parts by mass of the resin composition. It is 10 parts by mass or less. As a result, the balance of properties such as heat cycle resistance and adhesion to adherends is improved.

[Method for Promoting Sintering]
The method for promoting sintering according to the present embodiment is a method for promoting sintering of silver-containing particles using the sintering accelerator described above.

The sintering of the silver-containing particles can be promoted by adding the sintering accelerator described above to various resin compositions such as conductive pastes.

Although the embodiments of the present invention have been described above, these are examples of the present invention, and various configurations other than those described above can be adopted. Moreover, the present invention is not limited to the above-described embodiments, and includes modifications, improvements, etc. within the scope of achieving the object of the present invention.

EXAMPLES The present invention will be described below with reference to Examples and Comparative Examples, but the present invention is not limited to these.

[Preparation of conductive paste]
Varnishes 1 to 11 and A1 to A7 to be blended in the conductive paste for jet dispensing were prepared by uniformly mixing each component according to the formulations shown in Tables 1 and 3. The unit of content of each component in Tables 1 and 3 is parts by mass.

Details of the components shown in Tables 1 and 3 are as follows.

(sintering accelerator)
Sintering accelerator 1: polyethylene glycol diglycidyl ether (product name: Epolite 400E, manufactured by Kyoeisha Chemical Co., Ltd., corresponding to the above formula (1), m = 9)
・ Sintering accelerator 2: polyethylene glycol diglycidyl ether (product name: Denacol EX-821, manufactured by Nagase ChemteX Corporation, corresponding to the above formula (1), m = 4)
・ Sintering accelerator 3: polypropylene glycol diglycidyl ether (product name: Denacol EX-920, manufactured by Nagase ChemteX Corporation, corresponds to the above formula (2), n = 3)
・ Sintering accelerator 4: polypropylene glycol diglycidyl ether (product name: Denacol EX-931, manufactured by Nagase ChemteX Corporation, corresponds to the above formula (2), n = 11)
・ Sintering accelerator 5: polyethylene glycol diglycidyl ether (product name: Denacol EX-830, manufactured by Nagase ChemteX Corporation, corresponds to the above formula (1), n = 9)

(epoxy monomer)
・ Epoxy monomer 1: trimethylolpropane polyglycidyl ether (product name: Denacol EX-321L, manufactured by Nagase ChemteX Corporation)
・ Epoxy monomer 2: Bisphenol F type epoxy monomer (product name: RE-303S, manufactured by Nippon Kayaku Co., Ltd.)

(epoxy group-containing butadiene rubber)
・ Epoxy group-containing butadiene rubber 1: epoxy-modified polybutadiene (product name: NISSO-PB JP-200, manufactured by Nippon Soda Co., Ltd.)

((meth)acrylic monomer)
・ (Meth) acrylic monomer 1: 1,4-cyclohexanedimethanol monoacrylate (product name: CHDMMA, manufactured by Nippon Kasei Co., Ltd.)
・ (Meth) acrylic monomer 2: ethylene glycol dimethacrylate (product name: Light Ester EG, manufactured by Kyoeisha Chemical Co., Ltd.)

(curing agent)
・ Curing agent 1: Bisphenol F type phenolic resin (product name: DIC-BPF, manufactured by DIC Corporation)

(Curing accelerator)
・ Curing accelerator 1: 2-phenyl-1H-imidazole-4,5-dimethanol (product name: 2PHZ-PW, manufactured by Shikoku Kasei Co., Ltd.)

(Radical polymerization initiator)
・ Radical polymerization initiator 1: dicumyl peroxide (product name: Perkadox BC, manufactured by Kayaku Noorion Co., Ltd.)

Then, each component was uniformly mixed according to the formulations shown in Tables 2 and 4 to obtain a conductive paste. The unit for the content of each component in Tables 2 and 4 is parts by mass.

Details of the components shown in Tables 2 and 4 are as follows.
(Silver-containing particles)
・Silver filler 1: silver particles (product name: AG-DSB-114, manufactured by DOWA Electronics Co., Ltd., spherical, D ₅₀ : 0.7 μm, specific surface area: 1.05 m ² /g, tap density 5.25 g/cm ³ , Circularity: 0.953)
・Silver filler 2: silver particles (product name: HKD-12, manufactured by Fukuda Metal Foil & Powder Co., Ltd., scale-like, D ₅₀ : 7.6 μm, specific surface area: 0.315 m ² /g, tap density: 5.5 g / ^cm3 )
(solvent)
・Solvent 1: Tripropylene glycol mono-n-butyl ether (product name: BFTG, manufactured by Nippon Nyukazai Co., Ltd.)

[Preparation of cured product]
The resulting conductive paste was applied onto a glass plate, heated from 30° C. to 200° C. over 60 minutes in a nitrogen atmosphere, and then sintered at 200° C. for 120 minutes. Thereby, a cured product having a thickness of 0.05 mm was obtained.

[Volume resistivity]
The volume resistivity of the surface of the obtained cured product was measured by a DC four-electrode method using a milliohmmeter (manufactured by Hioki) using electrodes with an electrode spacing of 40 mm.

[Storage modulus]
A strip-shaped sample of about 0.1 mm x about 10 mm x about 4 mm was cut out from the obtained cured product, and the storage elastic modulus (E') at 25 ° C. was measured using the strip-shaped sample by DMA (dynamic viscoelasticity measurement, (tensile mode) at a temperature increase rate of 5° C./min and a frequency of 10 Hz.

As shown in Tables 2 and 4 above, it was confirmed that the conductive paste of each example had a smaller volume resistivity and superior conductivity compared to the conductive paste of the comparative example.

[SEM observation of cross section of cured product]
A section for SEM observation of about 4 mm×about 10 mm×about 50 μm is cut out from the obtained cured product, and the section for SEM observation is observed with a scanning electron microscope (manufactured by Hitachi High-Technologies Corporation, device name: MiniscopeTM3030) at a magnification of 5000. bottom.

The SEM observation image of Example 2 is shown in FIG. 2, and the SEM observation image of Comparative Example 1 is shown in FIG. In each SEM image, white portions are silver-containing particles. In the SEM observation image of Example 2, as compared with the SEM observation image of Comparative Example 1, it can be seen that the silver-containing particles are more fused together and sintering is promoted.

This application claims priority based on Japanese Patent Application No. 2021-155956 filed on September 24, 2021 and Japanese Patent Application No. 2022-141719 filed on September 6, 2022. , the disclosure of which is hereby incorporated in its entirety.

10 adhesive layer 20 semiconductor element 30 substrate 40 bonding wire 50 mold resin 60 solder ball 100 semiconductor device

Claims (15)

silver-containing particles;
a sintering accelerator that promotes sintering between the silver-containing particles;
A conductive paste containing
A conductive paste, wherein the sintering accelerator contains a compound represented by formula (1) or (2).

(In formula (1), m is an integer of 1 or more and 20 or less.)

(In formula (2), n is an integer of 1 or more and 20 or less.) The conductive paste according to claim 1,
A conductive paste, wherein the sintering accelerator contains a compound represented by formula (1), wherein m is an integer of 1 or more and 11 or less. The conductive paste according to claim 1 or 2,
A conductive paste, wherein the sintering accelerator contains a compound represented by formula (2), wherein n is an integer of 2 or more and 13 or less. The conductive paste according to any one of claims 1 to 3,
A conductive paste, wherein the silver-containing particles include one or more selected from the group consisting of spherical particles, scale-like particles, aggregated particles, and polyhedral particles. The conductive paste according to claim 4,
A conductive paste, wherein the silver-containing particles include two or more selected from the group consisting of spherical particles, scale-like particles, aggregated particles, and polyhedral particles. The conductive paste according to any one of claims 1 to 5,
A conductive paste further comprising an epoxy monomer. The conductive paste according to claim 6,
A conductive paste further comprising a phenolic hardener. The conductive paste according to claim 6 or 7,
An electrically conductive paste, further comprising an imidazole curing accelerator. The conductive paste according to any one of claims 1 to 8,
An electrically conductive paste further comprising a (meth)acrylic monomer. The conductive paste according to claim 9,
A conductive paste, further comprising a radical polymerization initiator. The conductive paste according to any one of claims 1 to 10,
A conductive paste further comprising a solvent. The conductive paste according to any one of claims 1 to 11,
The conductive paste was applied to a glass plate so that the thickness after sintering was 0.05 mm, and the temperature was raised from 30°C to 200°C over 60 minutes in a nitrogen atmosphere, and then to 200°C. is sintered for 120 minutes to obtain a cured product having a volume resistivity of 4.0 μΩ·cm or more and 9.5 μΩ·cm or less. A cured product obtained by sintering the conductive paste according to any one of claims 1 to 12. A sintering accelerator that promotes sintering between silver-containing particles,
A sintering accelerator containing a compound represented by formula (1) or (2).

(In formula (1), m is an integer of 1 or more and 20 or less.)

(In formula (2), n is an integer of 1 or more and 20 or less.) A method for accelerating sintering, which uses the sintering accelerator according to claim 14 to accelerate sintering of silver-containing particles.

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