JP2022069401A - Pasty composition, high thermal conductivity material, and semiconductor device - Google Patents

Abstract

To provide a pasty composition capable of forming a semiconductor device excellent in thermal conductivity by use in bonding a semiconductor element to a substrate.SOLUTION: The pasty composition contains silver-containing particles and a thermoacid generator represented by general formula (1), [A].[B], where [A] refers to a cationic species and [B] refers to an anionic species.SELECTED DRAWING: None

Description

The present invention relates to paste-like compositions, high thermal conductive materials, and semiconductor devices.

A technique for manufacturing a semiconductor device using a composition containing metal particles is known with the intention of enhancing the heat dissipation of the semiconductor device. By using metal particles having high thermal conductivity, the thermal conductivity of the cured product can be increased.
As a specific example of application to a semiconductor device, a technique for adhering / bonding a semiconductor element and a substrate (support member) using a composition containing metal particles is known as in Patent Documents 1 to 4 below. There is.

Patent Document 1 describes a thermosetting resin composition for semiconductor adhesion, which comprises a (meth) acrylic acid ester compound having a predetermined structure, a radical initiator, silver fine particles, silver powder, and a solvent. The semiconductor device to which the ester is bonded is disclosed. The document states that connection reliability for post-mounting temperature cycles can be improved (paragraph 0011).

Patent Document 2 discloses a resin paste composition containing an imide acrylate compound, a radical initiator, and a filler such as silver powder, and a semiconductor device in which a semiconductor element and a base material are bonded to each other in the composition. The document describes that the occurrence of chip cracks and chip warpage can be suppressed by reducing the stress of the resin paste composition (paragraph 0003).

Patent Document 3 describes a semiconductor having a structure in which a semiconductor element and a support member for mounting a semiconductor element are bonded to each other through a silver paste composition composed of silver particles satisfying predetermined physical property values, a solvent and an additive, and the composition. The device is disclosed. This document describes an example in which dipropylene glycol methyl ether acetate and isobonylcyclohexanol are used as a solvent.

Patent Document 4 describes a curable compound having an unsaturated double bond, a curable compound having an epoxy group, a thermal cation curing initiator, a thermal anion curing agent, and a cation generated from the thermal cation curing initiator. A conductive material containing a compound capable of capturing the above, conductive particles, and a connection structure in which an electronic component and a circuit board are bonded via the conductive material are disclosed. The document describes that the use of the conductive material can suppress the generation of voids in the connecting structure.

Japanese Unexamined Patent Publication No. 2014-74132 Japanese Unexamined Patent Publication No. 2000-239616 Japanese Unexamined Patent Publication No. 2014-225350 Japanese Unexamined Patent Publication No. 2013-229314

However, the semiconductor device in which the semiconductor element and the base material are bonded by using the compositions described in Patent Documents 1 to 4 has room for improvement in thermal conductivity.

The present inventors have found that good thermal conductivity can be obtained by using a thermoacid generator, and have completed the present invention.
That is, the present invention can be shown below.

According to the present invention
(A) Silver-containing particles and
(B) The thermal acid generator represented by the following general formula (1) and
A paste-like composition comprising the above is provided.
[A] ・ [B] ・ ・ ・ (1)
(In the general formula (1), [A] indicates a cation species and [B] indicates an anion species.)

According to the present invention
A high thermal conductive material obtained by sintering the paste-like composition is provided.

According to the present invention
With the base material
A semiconductor element mounted on the base material via an adhesive layer is provided.
A semiconductor device is provided in which the adhesive layer is obtained by sintering the paste-like composition.

According to the present invention, it is possible to provide a paste-like composition capable of obtaining a semiconductor device having excellent thermal conductivity by applying it to a bonding between a semiconductor element and a base material.

It is sectional drawing which shows an example of the semiconductor device schematically. It is sectional drawing which shows an example of the semiconductor device schematically.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all drawings, similar components are designated by the same reference numerals, and the description thereof will be omitted as appropriate. In addition, "-" represents "greater than or equal to" to "less than or equal to" unless otherwise specified.

The paste-like composition of this embodiment is
(A) Silver-containing particles and
(B) Containing a thermoacid generator.

[Silver-containing particles (a)]
The silver-containing particles (a) can be sintered (sintered) by an appropriate heat treatment to form a particle connecting structure (sintering structure).

In particular, since the paste-like composition contains silver-containing particles, and in particular, silver particles having a relatively small particle size and a relatively large specific surface area are contained, heat treatment at a relatively low temperature (about 180 ° C.) is performed. However, a sintered structure is likely to be formed. The preferred particle size will be described later.

The shape of the silver-containing particles (a) is not particularly limited. The preferred shape is spherical, but may be non-spherical, such as ellipsoidal, flat, plate-like, needle-like, scaly, agglomerated, and polyhedral. The silver-containing particles (a) can contain at least one kind of silver-containing particles having these shapes.

In the present embodiment, it is preferable to include two or more kinds selected from spherical, scaly, aggregated, and polyhedron-shaped silver-containing particles, and spherical silver-containing particles (a1) and scaly, aggregated particles. It is more preferable to include one or more kinds of silver-containing particles (a2) selected from the polyhedron shape, and to include spherical silver-containing particles (a1) and scaly silver-containing particles (a2-1). Is particularly preferable. As a result, the contact rate between the silver-containing particles is further improved, so that a network is easily formed after sintering of the paste-like composition, and the thermal conductivity and the electric conductivity are further improved.

When the silver-containing particles (a) contain the silver-containing particles (a2), it is possible to suppress resin cracks in the molded product obtained from the paste-like composition and suppress the linear expansion coefficient.
In the present embodiment, the "spherical shape" is not limited to a perfect true sphere, but also includes a shape having some irregularities on the surface. The circularity is, for example, 0.90 or more, preferably 0.92 or more, and more preferably 0.94 or more.

The surface of the silver-containing particles (a) is treated with an organic compound such as a carboxylic acid, a saturated fatty acid having 4 to 30 carbon atoms, an unsaturated fatty acid having 4 to 30 carbon atoms, and a long-chain alkylnitrile. May be good.

Normally, the silver-containing particles (a) are surface-treated to suppress aggregation, but the present inventors have found that the surface-treating agent affects the sintering of the silver-containing particles. As a result of further studies, it was also found that when the thermal acid generator (b) is added to the surface-treated silver-containing particles (a), a highly thermally conductive material having excellent thermal conductivity can be obtained. Although the mechanism of such an effect is not clear, the thermal acid generator (b) dissociates into anions and cations by heating such as sintering, and the cations react with the surface treatment agent to react from the surface of the silver-containing particles. It is considered that the removal of the surface treatment agent promotes the sintering of the silver-containing particles (a).

The silver-containing particles (a) may be (i) particles substantially composed of only silver, or (ii) particles composed of silver and components other than silver. Further, (i) and (ii) may be used in combination as the metal-containing particles.

In the present embodiment, the silver-containing particles (a) particularly preferably include silver-coated resin particles whose surfaces are coated with silver. This makes it possible to prepare a paste-like composition capable of obtaining a cured product having excellent thermal conductivity and a low storage elastic modulus.

Since the silver-coated resin particles have a silver surface and a resin inside, they are considered to have good thermal conductivity and are softer than particles composed only of silver. Therefore, it is considered easy to design the thermal conductivity and the storage elastic modulus to appropriate values by using the silver-coated resin particles.

Usually, in order to increase the thermal conductivity, it is considered to increase the amount of silver-containing particles. However, since metals are usually "hard", if the amount of silver-containing particles is too large, the elastic modulus after sintering may become too large. Since a part or all of the silver-containing particles are silver-coated resin particles, it is possible to easily design a paste-like composition capable of obtaining a cured product having a desired thermal conductivity and storage elastic modulus.
In the silver-coated resin particles, the silver layer may cover at least a part of the surface of the resin particles. Of course, silver may cover the entire surface of the resin particles.

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

As another viewpoint, 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, and more preferably 70/30 to 30/70. be.

Examples of the "resin" in the silver-coated resin particles include silicone resin, (meth) acrylic resin, phenol resin, polystyrene resin, melamine resin, polyamide resin, and polytetrafluoroethylene resin. Of course, resins other than these may be used. Further, only one kind of resin may be used, or two or more kinds of 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.
The silicone resin may be particles composed of organopolysiloxane obtained by polymerizing organochlorosilane such as methylchlorosilane, trimethyltrichlorosilane, and dimethyldichlorosilane. Further, a silicone resin having a structure in which organopolysiloxane is further three-dimensionally crosslinked may be used as a basic skeleton.

The (meth) acrylic resin is a resin obtained by polymerizing a monomer containing a (meth) acrylic acid ester as a main component (50% by weight or more, preferably 70% by weight or more, more preferably 90% by weight or more). be able to. Examples of the (meth) acrylic acid ester include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and lauryl (meth) acrylate. , Stearyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-propyl (meth) acrylate, chloro-2-hydroxyethyl (meth) acrylate, diethylene glycol mono (meth) acrylate, At least one compound selected from the group consisting of methoxyethyl (meth) acrylate, glycidyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate and isoboronor (meth) acrylate can be mentioned. can. Further, the monomer component of the acrylic resin may contain a small amount of other monomers. Examples of such other monomer components include styrene-based monomers. For the silver-coated (meth) acrylic resin, refer to the description in JP-A-2017-126463.

Various functional groups may be introduced into the silicone resin or the (meth) acrylic resin. The functional groups that can be introduced are not particularly limited. For example, an epoxy group, an amino group, a methoxy group, a phenyl group, a carboxyl group, a hydroxyl group, an alkyl group, a vinyl group, a mercapto group and the like can be mentioned.

The portion of the resin particles in the silver-coated resin particles may contain various additive components such as a low stress modifier. Examples of the low stress modifier include butadiene styrene rubber, butadiene acrylonitrile rubber, polyurethane rubber, polyisoprene rubber, acrylic rubber, fluororubber, liquid organopolysiloxane, liquid synthetic rubber such as liquid polybutadiene, and the like. In particular, when the portion of the resin particles contains a silicone resin, the elastic properties of the silver-coated resin particles can be made preferable by containing a low stress modifier.

The shape of the portion of the resin particles in the silver-coated resin particles is not particularly limited. A combination of a spherical shape and an irregular shape other than the spherical shape, for example, a flat shape, a plate shape, a needle shape, or the like is preferable.

The specific gravity of the silver-coated resin particles is not particularly limited, but the lower limit is, for example, 2 or more, preferably 2.5 or more, and more preferably 3 or more. The upper limit of the specific gravity is, for example, 10 or less, preferably 9 or less, and more preferably 8 or less. The appropriate specific gravity is preferable in terms of the dispersibility of the silver-coated resin particles themselves and the uniformity when the silver-coated resin particles and other silver-containing particles are used in combination.

When silver-coated resin particles are used, the proportion of the silver-coated resin particles in the entire silver-containing particles (a) is preferably 1 to 50% by mass, more preferably 3 to 45% by mass, and further preferably 5 to 40% by mass. Is. By appropriately adjusting this ratio, it is possible to further improve the heat dissipation while suppressing the decrease in the adhesive force due to the heat cycle.

Incidentally, when the ratio of the silver-coated resin particles in the whole silver-containing particles (a) is not 100% by mass, the silver-containing particles other than the silver-coated resin particles are, for example, particles substantially composed of only silver.

The median diameter D ₅₀ of the silver-containing particles (a) is, for example, 0.01 to 50 μm, preferably 0.1 to 20 μm, and more preferably 0.5 to 10 μm. By setting D ₅₀ to an appropriate value, it is easy to balance thermal conductivity, sinterability, heat cycle resistance, and the like. Further, by setting D50 to an appropriate value, it may be possible to improve the workability of coating / bonding.
The particle size distribution (horizontal axis: particle diameter, vertical axis: frequency) of the silver-containing particles may be monomodal or multimodal.

From the viewpoint of the effect of the present invention, it is preferable that the silver-containing particles (a) include spherical silver-containing particles (a1) and scaly silver-containing particles (a2-1). It is more preferable that these silver-containing particles are silver particles substantially composed of only silver.

The median diameter D ₅₀ of the spherical silver-containing particles (a1) is, for example, 0.1 to 20 μm, preferably 0.5 to 10 μm, and more preferably 0.5 to 5.0 μm.
The specific surface area of the spherical silver-containing particles (a1) is, for example, 0.1 to 2.5 m ² / g, preferably 0.5 to 2.3 m ² / g, and more preferably 0.8 to 2.0 m ² / g. g.
The tap density of the spherical silver-containing particles (a1) is, for example, 1.5 to 6.0 g / cm ³ , preferably 2.5 to 5.8 g / cm ³ , and more preferably 4.5 to 5.5 g / cm. It is ³ .
The circularity of the spherical silver-containing particles (a1) is, for example, 0.90 or more, preferably 0.92 or more, and more preferably 0.94 or more.
By satisfying each of these characteristics, the balance of thermal conductivity, sinterability, resistance to heat cycle, etc. is excellent.

The median diameter D ₅₀ of the scaly silver-containing particles (a2-1) is, for example, 0.1 to 20 μm, preferably 1.0 to 15 μm, and more preferably 2.0 to 10 μm.
The specific surface area of the scaly silver-containing particles (a2-1) is, for example, 0.1 to 2.5 m ² / g, preferably 0.2 to 2.0 m ² / g, and more preferably 0.25 to 1. It is 2 m ² / g.
The tap density of the scaly silver-containing particles (a2-1) is, for example, 1.5 to 6.0 g / cm ³ , preferably 2.5 to 5.9 g / cm ³ , and more preferably 4.0 to 5. It is 8 g / cm ³ .
By satisfying each of these characteristics, the balance of thermal conductivity, sinterability, resistance to heat cycle, etc. is excellent.

In the present embodiment, heat is obtained by combining spherical silver-containing particles (a1) satisfying at least one of the above characteristics and scaly silver-containing particles (a2-1) satisfying at least one of the above characteristics. Conductivity and electrical conductivity are particularly improved.

The ratio (a1 / a2-1) of the content of the spherical silver-containing particles (a1) to the content of the scaly silver-containing particles (a2-1) is preferably 0.1 or more and 10 or less, more preferably 0. It can be 3 or more and 5 or less, particularly preferably 0.5 or more and 3 or less. As a result, the contact rate between the silver-containing particles is particularly improved, so that a network is easily formed after sintering of the paste-like polymerizable composition, and the thermal conductivity and the electrical conductivity are particularly improved.

The ratio (a1 / a2-1) of the median diameter D ₅₀ of the spherical silver-containing particles (a1) to the median diameter D ₅₀ of the scaly silver-containing particles (a2-1) is preferably 0.01 or more and 0.8 or less. , More preferably 0.05 or more and 0.6 or less.
As a result, the voids between the scaly silver-containing particles are efficiently filled with the spherical silver-containing particles, and the contact rate between the silver-containing particles is particularly improved. Therefore, the paste-like polymerizable composition is sintered. Later, the network is easily formed and the thermal and electrical conductivity are particularly improved.

The ratio (a1 / a2-1) of the tap density of the spherical silver-containing particles b1 to the tap density of the scaly silver-containing particles (a2-1) is preferably 0.5 or more and 2.0 or less, more preferably 0. 7 or more and 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. Therefore, a network is easily formed after sintering of the paste-like polymerizable composition, and thermal conductivity and electricity are easily formed. Conductivity is particularly improved.

The median diameter D ₅₀ of the silver-coated resin particles is, for example, 5.0 to 25 μm, preferably 7.0 to 20 μm, and more preferably 8.0 to 15 μm. Thereby, the thermal conductivity can be further improved.

The median diameter D ₅₀ of the silver-containing particles (a) can be obtained by performing particle image measurement using, for example, a flow-type particle image analyzer FPIA (registered trademark) -3000 manufactured by Sysmex Corporation. More specifically, the particle diameter of the silver-containing particles (a) can be determined by measuring the volume-based median diameter in a wet manner using this device.

The proportion of the silver-containing particles (a) in the entire paste-like composition is, for example, 1 to 98% by mass, preferably 30 to 95% by mass, and more preferably 50 to 90% by mass. By setting the ratio of the metal-containing particles to 1% by mass or more, it is easy to increase the thermal conductivity. By setting the proportion of the silver-containing particles (a) to 98% by mass or less, the workability of coating / bonding can be improved.

Among the silver-containing particles (a), particles consisting substantially only of silver can be obtained from, for example, DOWA Hightech Co., Ltd., Fukuda Metal Foil Powder Industry Co., Ltd. and the like. Further, the silver-coated resin particles can be obtained from, for example, Mitsubishi Materials Corporation, Sekisui Chemical Co., Ltd., Sanno Co., Ltd., and the like.

[Thermal acid generator (b)]
The thermal acid generator (b) is represented by the general formula (1) [A], [B] ... (1).
In the general formula (1), [A] indicates a cation species and [B] indicates an anion species.

As the cation species, known cation species can be used as long as the effects of the present invention can be exhibited, but sulfonium cations or ammonium cations are preferable.
From the viewpoint of the effect of the present invention, the cation species is more preferably selected from the cation species represented by the following formulas (a1) to (a6).

As the anion species, known anion species can be used as long as the effects of the present invention can be exhibited, but from the viewpoint of the effects of the present invention, they are preferably represented by the following formulas (b1) to (b4). Selected from anions.

(B2) PF _6- ^,
(B3) CF ₃ SO _3- ^,
(B4 ⁾ SbF _6-
In this embodiment, it is more preferable to use the anion of (b1).

The thermal acid generator (b) preferably has an exothermic peak in a temperature region of 250 ° C. or lower, preferably 230 ° C. or lower, and more preferably 210 ° C. or lower in the DSC curve obtained under the following conditions.
(Test conditions)
A composition obtained by mixing 68.0 parts by mass of an epoxy resin, 27.0 parts by mass of a phenol resin, and 5.0 parts by mass of a thermoacid generator (b) was heated at a heating rate using a differential scanning calorimeter. The temperature is raised from 30 ° C. to 300 ° C. under the condition of 10 ° C./min to obtain a DSC curve.

When the thermal acid generator (b) has an exothermic peak in the above temperature region, it acts on the surface of the silver-containing particles (a) in the heating step in sintering, and the silver-containing particles (a) are surface-treated. Since it acts on the surface treatment agent as described above, it is possible to obtain a highly thermally conductive material having further excellent thermal conductivity.

From the viewpoint of the effect of the present invention, the thermal acid generator (b) is 0.01 part by mass or more and 1.0 part by mass or less, preferably 0.05 part by mass or more and 0. It can be contained in an amount of 9 parts by mass or less, more preferably 0.07 parts by mass or more and 0.8 parts by mass or less.

<Paste-like composition>
The paste-like composition of the present embodiment can be used as a sintering-type paste-like composition, a binder-type paste-like composition, or a half-sintering-type paste-like composition.

The sintering type paste-like composition is a composition in which silver-containing particles (a) are dispersed in a volatile organic solvent (dispersion medium), and the dispersion medium is volatilized by heat treatment to cause silver-containing particles (dispersion medium). By sintering a), conduction can be ensured and conductivity and thermal conductivity can be exhibited.
That is, the sintering type paste-like composition contains silver-containing particles (a), a thermal acid generator (b), and an organic solvent (c).

The binder-type paste-like composition is a composition in which silver-containing particles (a) are dispersed in a liquid thermosetting resin, and the silver-containing particles (a) are pressure-bonded by curing the resin by heating. Therefore, it is possible to develop conductivity and thermal conductivity.
That is, the binder-type paste-like composition contains silver-containing particles (a), a thermosetting agent (b), and a thermosetting resin (d), and further includes a curing agent (e) and a curing accelerator (a curing accelerator). f), radical initiator (g) and the like can be contained.

The half-sintering type paste-like composition is obtained by sintering and crimping the silver-containing particles (a) described above. That is, the half-sintering type paste-like composition contains silver-containing particles (a), a thermoacid generator (b), an organic solvent (c), and a thermosetting resin (d), and is further cured. The agent (e), the curing accelerator (f), the radical initiator (g) and the like can be contained.
Any type of paste-like composition may contain a silane coupling agent, a plasticizer, or the like as other components.

[Organic solvent (c)]
Examples of the organic solvent (c) include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, and ethylene glycol monobutyl ether. Propropylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, methylmethoxybutanol, α-terpineol, β-terpineol, hexylene glycol, benzyl alcohol, 2-phenylethyl alcohol, isopalmityl Alcohols such as alcohol, isostearyl alcohol, lauryl alcohol, ethylene glycol, propylene glycol, butyl propylene triglycol, and 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-cyclohexene-1-one), Ketones such as diisobutyl ketone (2,6-dimethyl-4-heptanone);
Ethyl acetate, butyl acetate, diethyl phthalate, dibutyl phthalate, acetoxyetane, methyl butyrate, methyl hexanoate, methyl octanate, methyl decanoate, methyl cellosolve acetate, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, 1,2- Esters such as diacetoxyetane, tributyl phosphate, tricresyl phosphate, tripentyl phosphate, etc.;
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, 1,2-bis (2-methoxyethoxy) ) Ethers such as ethane;
Ester ethers such as 2- (2 butoxyethoxy) ethane acetate;
Ether alcohols such as 2- (2-methoxyethoxy) ethanol;
Hydrocarbons such as toluene, xylene, n-paraffin, isoparaffin, dodecylbenzene, turpentine oil, kerosene, and light oil;
Nitriles such as acetonitrile or propionitrile;
Amides such as acetamide, N, N-dimethylformamide;
Silicone oils such as low molecular weight volatile silicone oils and volatile organic modified silicone oils;
Examples thereof include monofunctional (meth) acrylic compounds.
When the organic solvent (c) is used, only one kind of solvent may be used, or two or more kinds of solvents may be used in combination.

When the organic solvent (c) is used, the amount thereof is not particularly limited. The amount used may be appropriately adjusted based on the desired fluidity and the like. As an example, the organic solvent (c) is used in an amount such that the concentration of the non-volatile component of the paste-like composition is 50 to 95% by mass.

[Thermosetting resin (d)]
The thermosetting resin (d) usually contains a group that polymerizes / crosslinks by the action of an active chemical species such as a radical, and / or a chemical structure that reacts with the curing agent (e) described later. The thermosetting resin (d) contains, for example, one or more of an epoxy group, an oxetanyl group, a group containing an ethylenic carbon-carbon double bond, a hydroxy group, an isocyanate group, a maleimide structure, and the like.
As the thermosetting resin (d), an epoxy resin can be preferably mentioned.
The epoxy resin may be a compound having only one epoxy group in one molecule, or may be a compound having two or more epoxy groups in one molecule.

Examples of the epoxy resin include bifunctional or crystalline epoxy resins such as biphenyl type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, stilben type epoxy resin, and hydroquinone type epoxy resin; cresol novolac type epoxy resin, Novolak type epoxy resin such as phenol novolac type epoxy resin, naphthol novolak type epoxy resin; phenol aralkyl type epoxy resin containing phenylene skeleton, phenol aralkyl type epoxy resin containing biphenylene skeleton, phenol aralkyl type epoxy resin such as naphthol aralkyl type epoxy resin containing phenylene skeleton Resin: Trifunctional epoxy resin such as triphenol methane type epoxy resin and alkyl modified triphenol methane type epoxy resin; Modified phenol type epoxy resin such as dicyclopentadiene modified phenol type epoxy resin and terpene modified phenol type epoxy resin; Triazine nucleus Examples thereof include a heterocycle-containing epoxy resin such as a contained epoxy resin.

Further, as the epoxy group-containing compound, a monofunctional epoxy group-containing compound such as 4-tert-butylphenyl glycidyl ether, m, p-cresyl glycidyl ether, phenyl glycidyl ether, cresyl glycidyl ether and the like can also be included.
The paste-like composition of the present embodiment may contain only one thermosetting component, or may contain two or more thermosetting components.

Epoxy resin is preferable as the thermosetting resin (d). Preferred examples of the epoxy resin include bisphenol A type epoxy resin and bisphenol F type epoxy resin.
The amount of the thermosetting resin (d) in the paste-like composition of the present embodiment is, for example, 20 to 80% by mass, preferably 40 to 60% by mass, based on the total non-volatile components.

[Curing agent (e)]
Examples of the curing agent (e) include those having a reactive group that reacts with the thermosetting resin (d). The curing agent (e) contains, for example, a reactive group that reacts with a functional group such as an epoxy group, a maleimide group, or a hydroxy group contained in the thermosetting resin (d).

The curing agent (e) preferably contains a phenol-based curing agent and / or an imidazole-based curing agent. These curing agents are particularly preferable when the thermosetting component contains an epoxy group.
The phenolic curing agent may be a low molecular weight compound or a high molecular weight compound (that is, a phenol resin).

Examples of the phenolic curing agent which is a low molecular weight compound include bisphenol compounds such as bisphenol A and bisphenol F (dihydroxydiphenylmethane) (phenol resins having a bisphenol F skeleton); compounds having a biphenylene skeleton such as 4,4'-biphenol. And so on.

Specifically, as the phenol resin, a novolak type phenol resin such as a phenol novolac resin, a cresol novolak resin, a bisphenol novolak resin, a phenol-biphenylnovolak resin; a polyvinylphenol; a polyfunctional phenol resin such as a triphenylmethane type phenol resin; a terpene. Modified phenol resins such as 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 phenylene and / or biphenylene skeletons, and the like. be able to.
When the curing agent (e) is used, only one type may be used, or two or more types may be used in combination.

When the paste-like composition of the present embodiment contains the curing agent (e), the amount thereof is, for example, 10 to 120 parts by mass, preferably 30 to 30 parts by mass, when the amount of the thermosetting resin (d) is 100 parts by mass. It is 80 parts by mass.

(Curing accelerator (f))
The curing accelerator (f) typically accelerates the reaction between the thermosetting resin (d) and the curing agent (e).

Specifically, as the curing accelerator (f), a phosphorus atom-containing compound such as an organic phosphine, a tetra-substituted phosphonium compound, a phosphobetaine compound, an adduct of a phosphine compound and a quinone compound, and an adduct of a phosphonium compound and a silane compound; Examples include amidines and tertiary amines such as dicyandiamide, 1,8-diazabicyclo [5.4.0] undecene-7, and benzyldimethylamine; and nitrogen atom-containing compounds such as the amidine or the quaternary ammonium salt of the tertiary amine. Be done.
When the curing accelerator (f) is used, only one kind may be used, or two or more kinds may be used in combination.

When the paste-like composition of the present embodiment contains the curing accelerator (f), the amount thereof is preferably 0.1 to 10 parts by mass, for example, when the amount of the thermosetting resin (d) is 100 parts by mass. Is 0.5 to 5 parts by mass.

[Radical initiator (g)]
The radical initiator (g) can, for example, prevent insufficient curing, sufficiently promote the curing reaction at a relatively low temperature (for example, 180 ° C.), and further enhance the adhesive strength. It may be possible to improve it.
Examples of the radical initiator (g) include peroxides and azo compounds.

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, 2,2-di (4,4-di (t-butylperoxy) cyclohexyl) propane;
Hydroperoxides such as p-menthane hydroperoxide, diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutylhydroperoxide, cumene hydroperoxide, t-butylhydroperoxide;

To 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) hexin-3, di-t-butyl peroxide;
Diacyl peroxides such as dibenzoyl peroxide and di (4-methylbenzoyl) peroxide;
Peroxydicarbonates such as di-n-propylperoxydicarbonate and diisopropylperoxydicarbonate;
Peroxyesters such as 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, t-hexylperoxybenzoate, t-butylperoxybenzoate, t-butylperoxy2-ethylhexanonate, etc. Can be mentioned.

Examples of the azo compound include 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis (2-cyclopropylpropionitrile), and 2,2'-azobis (2,). 4-Dimethylvaleronitrile) and the like can be mentioned.
When the radical initiator (g) is used, only one kind may be used, or two or more kinds may be used in combination.

When the paste-like composition of the present embodiment contains a radical initiator (g), the amount thereof is preferably 0.1 to 20 parts by mass, for example, when the amount of the thermosetting resin (d) is 100 parts by mass. Is 0.5 to 10 parts by mass.

(Silane coupling agent)
The paste-like composition of the present embodiment can further contain a silane coupling agent. As a result, the adhesive strength can be further improved.

Examples of the silane coupling agent include known silane coupling agents, and specifically, vinylsilanes such as nyltrimethoxysilane and vinyltriethoxysilane;
2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidyloxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyl Epoxysilanes such as methyldiethoxysilane, 3-glycidoxypropyltriethoxysilane;
Styrylsilanes such as p-styryltrimethoxysilane;
Methylsilanes such as 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane;
Acrylic silanes such as 3- (trimethoxysilyl) propyl methacrylate, 3-acryloxypropyltrimethoxysilane;
N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, Aminosilanes such as 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, N-phenyl-γ-aminopropyltrimethoxysilane;
Isocyanurate silane;
Alkylsilane;
Ureidosilanes such as 3-ureidopropyltrialkoxysilanes;
Mercaptosilanes such as 3-mercaptopropylmethyldimethoxysilane and 3-mercaptopropyltrimethoxysilane;
Examples thereof include isocyanatesilane such as 3-isocyanatepropyltriethoxysilane.
When a silane coupling agent is used, only one type may be used, or two or more types may be used in combination.

When the paste-like composition of the present embodiment contains a silane coupling agent, the amount thereof is, for example, 0.1 to 10 parts by mass, preferably 0.5 when the thermosetting resin (d) is 100 parts by mass. ~ 5 parts by mass.

(Plasticizer)
The paste-like composition of the present embodiment can contain a plasticizer. Due to the plasticizer, the storage elastic modulus is low and it is easy to design. Then, it becomes easier to suppress the decrease in the adhesive force due to the heat cycle.

Specific examples of the plasticizer include a polyester compound, a silicone oil, a silicone compound such as silicone rubber, a polybutadiene compound such as a polybutadiene anhydride maleic acid adduct, and an acrylonitrile butadiene copolymer compound.
When a plasticizer is used, only one type may be used, or two or more types may be used in combination.

When the paste-like composition of the present embodiment contains a plasticizer, the amount thereof is, for example, 5 to 50 parts by mass, preferably 10 to 30 parts by mass, when the thermosetting resin (d) is 100 parts by mass. ..

(Characteristics of composition)
The paste-like composition of the present embodiment is preferably in the form of a paste at 20 ° C. That is, the paste-like composition of the present embodiment can be preferably applied to a substrate or the like at 20 ° C. like glue. As a result, the paste-like composition of the present embodiment can be preferably used as an adhesive for semiconductor devices and the like.
Of course, depending on the process to be applied, the paste-like composition of the present embodiment may be in the form of a varnish having a relatively low viscosity.
The paste-like composition of the present embodiment can be obtained by mixing the above components by a conventionally known method.

<High thermal conductivity material>
A highly thermally conductive material can be obtained by sintering the paste-like composition of the present embodiment.
By changing the shape of the highly thermally conductive material, it can be applied to various parts that require heat dissipation in the fields of automobiles and electric appliances.

<Semiconductor device>
A semiconductor device can be manufactured using the paste-like composition of the present embodiment. For example, a semiconductor device can be manufactured by using the paste-like composition of the present embodiment as an "adhesive" between a base material and a semiconductor element.

In other words, the semiconductor device of the present embodiment includes, for example, a base material and a semiconductor element mounted on the base material via an adhesive layer obtained by sintering the above-mentioned paste-like composition by heat treatment. ..
In the semiconductor device of the present embodiment, the adhesiveness of the adhesive layer is unlikely to decrease even with a heat cycle. That is, the reliability of the semiconductor device of this embodiment is high.

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

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

The semiconductor device 100 includes a base material 30 and a semiconductor element 20 mounted on the base material 30 via an adhesive layer 10 (diatack material) which is a heat-treated body of a paste-like composition.

The semiconductor element 20 and the base material 30 are electrically connected via, for example, a bonding wire 40 or the like. Further, the semiconductor element 20 is sealed with, for example, a sealing resin 50.

The thickness of the adhesive layer 10 is preferably 5 μm or more, more preferably 10 μm or more, still more preferably 20 μm or more. As a result, the stress absorption capacity of the paste-like composition can be improved, and the heat cycle resistance can be improved.
The thickness of the adhesive layer 10 is, for example, 100 μm or less, preferably 50 μm or less.

In FIG. 1, the base material 30 is, for example, a lead frame. In this case, the semiconductor element 20 is mounted on the die pad 32 or the base material 30 via the adhesive layer 10. Further, the semiconductor element 20 is electrically connected to the outer lead 34 (base material 30) via, for example, a bonding wire 40. The base material 30 which is a lead frame is composed of, for example, a 42 alloy, a Cu frame, or the like.

The base material 30 may be an organic substrate or a ceramic substrate. Examples of the organic substrate include those made of an epoxy resin, a cyanate resin, a maleimide resin, or the like.
The surface of the base material 30 may be coated with a metal such as silver or gold. This improves the adhesiveness between the adhesive layer 10 and the base material 30.

FIG. 2 is a cross-sectional view showing an example of a semiconductor device 100 different from that of FIG.
In the semiconductor device 100 of FIG. 2, the base material 30 is, for example, an interposer. Of the base material 30 that is an interposer, for example, a plurality of solder balls 52 are formed on the surface opposite to one surface on which the semiconductor element 20 is mounted. In this case, the semiconductor device 100 is connected to another wiring board via the solder balls 52.
An example of a method for manufacturing a semiconductor device will be described.

First, the paste-like composition is applied onto the base material 30, and then the semiconductor element 20 is arranged on the paste-like composition. That is, the base material 30, the paste-like composition, and the semiconductor element 20 are laminated in this order.
The method of applying the paste-like composition is not particularly limited. Specific examples thereof include a dispensing method, a printing method, and an inkjet method.

Then, the paste-like composition is heat-cured. The thermosetting is preferably performed by pre-curing and post-curing. The paste-like composition is made into a heat-treated body (cured product) by thermosetting. By thermosetting (heat treatment), the metal-containing particles in the paste-like composition are aggregated, and a structure in which the interface between the plurality of metal-containing particles disappears is formed in the adhesive layer 10. As a result, the base material 30 and the semiconductor element 20 are adhered to each other via the adhesive layer 10. Next, the semiconductor element 20 and the base material 30 are electrically connected using the bonding wire 40. Next, the semiconductor element 20 is sealed with the sealing resin 50. In this way, the semiconductor device can be manufactured.

Although the embodiments of the present invention have been described above, these are examples of the present invention, and various configurations other than the above can be adopted. Further, the present invention is not limited to the above-described embodiment, and modifications, improvements, and the like to the extent that the object of the present invention can be achieved are included in the present invention.

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited thereto.
The components used in the examples are shown below.

(Thermosetting component)
Epoxy resin 1: Bisphenol F type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., RE-303S)
-Acrylic monomer 1: Ethylene glycol dimethacrylate (Kyoeisha Chemical Co., Ltd., light ester EG)

(Hardener)
-Curing agent 1: Phenol resin having a bisphenol F skeleton (solid at room temperature 25 ° C, manufactured by DIC, DIC-BPF)

(Curing accelerator)
-Imidazole-based catalyst 1: 2-phenyl-1H-imidazole-4,5-dimethanol (manufactured by Shikoku Chemicals Corporation, 2PHZ-PW)

(Radical polymerization initiator)
-Radical polymerization initiator 1: Dicumyl peroxide (manufactured by Kayaku Akzo, Percadox BC)

(Thermal acid generator)
・ Thermal acid generator 1: Thermal acid generator represented by the following formula (manufactured by Sanshin Chemical Industry Co., Ltd.)

・ Thermal acid generator 2: Thermal acid generator represented by the following formula (manufactured by Sanshin Chemical Industry Co., Ltd.)

-Heat acid generator 3: Heat acid generator represented by the following formula (manufactured by Sanshin Chemical Industry Co., Ltd.)

・ Thermal acid generator 4 Thermal acid generator represented by the following formula (manufactured by Asahi Glass Co., Ltd.)

-Heat acid generator 5: A heat acid generator represented by the following formula (manufactured by Kusumoto Kasei Co., Ltd.)

-Heat acid generator 6: Heat acid generator represented by the following formula (manufactured by Sanshin Chemical Industry Co., Ltd.)

-Heat acid generator 7: Heat acid generator represented by the following formula (manufactured by Kusumoto Kasei Co., Ltd.)
Quaternary ammonium salt ^, CF ₃ SO _3-

・ Thermal acid generator 8: Thermal acid generator represented by the following formula (manufactured by Sanshin Chemical Industry Co., Ltd.)

Thermal acid generator 9: Thermal acid generator represented by the following formula (manufactured by Sanshin Chemical Industry Co., Ltd.)

(Silver-containing particles)
-Silver filler 1: Made by DOWA Electronics, AG-DSB-114, 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: Made by Fukuda Metal Foil Powder Industry Co., Ltd., HKD-12, scaly, median diameter D ₅₀ : 7.6 μm, specific surface area: 0.315 m ² / g, tap density: 5.5 g / cm ³

(solvent)
Solvent 1: Tripropylene glycol mono-n-butyl ether (BFTG, manufactured by Nippon Embroidery Co., Ltd., boiling point 274 ° C)

[Examples 1 to 14, Comparative Example 1]
Each raw material component was uniformly dispersed and kneaded using three rolls according to the blending amount shown in Table 1. After kneading, the mixture was defoamed under reduced pressure at room temperature for 15 minutes to obtain a paste-like polymerizable composition.

(Volume resistivity)
The paste-like composition was applied onto a glass plate, heated from 30 ° C. to 200 ° C. over 60 minutes under a nitrogen atmosphere, and then heat-treated at 200 ° C. for 120 minutes. As a result, a heat-treated body (cured product) of a paste-like polymerizable composition having a thickness of 0.05 mm was obtained. The resistance value on the surface of the heat-treated body was measured using a DC four-electrode method using a milliome meter (manufactured by HIOKI) and electrodes having an electrode spacing of 40 mm.

From the results shown in Table 1, it was confirmed that the cured product obtained from the paste-like composition containing a predetermined thermal acid generator has low volume efficiency and excellent thermal conductivity.

100 Semiconductor device 10 Adhesive layer 20 Semiconductor element 30 Base material 32 Die pad 34 Outer lead 40 Bonding wire 50 Encapsulating resin 52 Solder ball

Claims (15)

(A) Silver-containing particles and
(B) The thermal acid generator represented by the following general formula (1) and
A paste-like composition comprising.
[A] ・ [B] ・ ・ ・ (1)
(In the general formula (1), [A] indicates a cation species and [B] indicates an anion species.) The paste-like composition according to claim 1, wherein the cation species is a sulfonium cation or an ammonium cation. The paste-like composition according to claim 1 or 2, wherein the anion species is selected from the following (b1) to (b4) anions.

(B2) PF _6- ^,
(B3) CF ₃ SO _3- ^,
(B4 ⁾ SbF _6- The paste-like composition according to any one of claims 1 to 3, wherein [B] is an anion (b1) in the thermal acid generator (b) represented by the general formula (1). The paste-like composition according to any one of claims 1 to 4, wherein the thermoacid generator (b) has an exothermic peak in a temperature region of 250 ° C. or lower in a DSC curve obtained under the following conditions.
(Test conditions)
A composition obtained by mixing 68.0 parts by mass of an epoxy resin, 27.0 parts by mass of a phenol resin, and 5.0 parts by mass of a thermoacid generator (b) was heated at a heating rate using a differential scanning calorimeter. The temperature is raised from 30 ° C. to 300 ° C. under the condition of 10 ° C./min to obtain a DSC curve. The paste-like composition according to any one of claims 1 to 5, wherein the amount of the thermoacid generator (b) with respect to 100 parts by mass of the paste-like composition is 0.01 parts by mass or more and 1.0 part by mass or less. .. The paste-like composition according to any one of claims 1 to 6, further comprising an organic solvent (c). The paste-like composition according to any one of claims 1 to 6, further comprising an organic solvent (c) and a thermosetting resin (d). The paste-like composition according to claim 8, wherein the thermosetting resin (d) contains an epoxy resin. The paste-like composition according to claim 9, further comprising a curing agent (e). The paste-like composition according to any one of claims 1 to 6, further comprising a thermosetting resin (d). The paste-like composition according to claim 11, wherein the thermosetting resin (d) contains an epoxy resin. The paste-like composition according to claim 11 or 12, further comprising a curing agent (e). A highly thermally conductive material obtained by sintering the paste-like composition according to any one of claims 1 to 13. With the base material
A semiconductor element mounted on the base material via an adhesive layer is provided.
The adhesive layer is a semiconductor device obtained by sintering the paste-like composition according to any one of claims 1 to 13.

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