Conductive resin composition, high thermal conductive material and semiconductor device

Abstract

The conductive resin composition of the present invention contains (A) silver particles and (B) an aliphatic epoxy compound with more than three functions, and the content of silver particles (A) is 81% by mass or more.

Description

Technical Field

[0001] This invention relates to a conductive resin composition, a highly thermally conductive material, and a semiconductor device. Prior Technology

[0002] In the manufacture of semiconductor devices, conductive resin compositions with conductivity and adhesion are sometimes used. Various compositions have been developed to date as conductive resin compositions with conductivity and adhesion.

[0003] Patent Document 1 discloses a thermally and electrically conductive adhesive composition containing a conductive filler composed of silver powder having a specified average particle size, an epoxy resin, a reactive diluent having one or more glycidyl functional groups on an aliphatic hydrocarbon chain, and a curing agent. This document describes an epoxy resin having two or more epoxy functional groups and an aromatic ring within one molecule. Furthermore, examples of the aforementioned reactive diluent include cyclohexanediethanol diglycidyl ether or neopentyl glycol diglycidyl ether.

[0004] Patent Document 2 discloses a conductive adhesive containing a specified epoxypropyl ether compound, a specified phenolic resin-based curing agent, a curing accelerator, and a conductive filler, wherein the phenolic resin-based curing agent is contained in a specified amount relative to the aforementioned epoxypropyl ether compound. This document describes an epoxy resin having two or more epoxy functional groups and aromatic rings within one molecule. Examples of the aforementioned epoxypropyl ether compound in this document include 1,4-cyclohexanediethanol diepoxypropyl ether or neopentyl tert-tetraepoxypropyl ether.

[0005] Patent Document 3 discloses a thermally and electrically conductive adhesive composition containing a conductive filler, an epoxy resin, a reactive diluent having two or more glycidyl ether functional groups on an aliphatic hydrocarbon chain, and a curing agent. Examples of the reactive diluent in this document include cyclohexanediethanol diglycidyl ether or neopentyl glycol diglycidyl ether. Furthermore, the technology described in this document relates to an adhesive composition in which adhesion is imparted by a resin; therefore, the adhesive composition of the example contains 80% by mass of silver particles, i.e., a conductive filler. [Previous Technical Documents] [Patent Literature]

[0006] [Patent Document 1] International Publication No. 2018 / 225773 [Patent Document 2] Japanese Patent Application Publication No. 2015-160932 [Patent Document 3] Japanese Patent Application Publication No. 2015-224329 Summary of the Invention

[0007] [The problem that the invention aims to solve]

[0008] However, when using the conductive adhesives described in Patent Documents 1 to 3 to attach semiconductor elements to a substrate, there is room for improvement in conductivity and product reliability. [Technical means to solve the problem]

[0009] The inventors discovered that by combining a specified amount or more of silver-containing particles and a multifunctional aliphatic epoxy compound, the above-mentioned problems can be solved, thus completing the present invention. That is, the present invention can be as follows.

[0010] [1] A conductive resin composition comprising: (A) Contains silver particles; and (B) Aliphatic epoxides with three or more functions, and The content of silver particles (A) is 81% by mass or more. [2] As in [1], a conductive resin composition, wherein, The aliphatic epoxy compound (B) with three or more functions contains at least one compound selected from those represented by the following general formula (1). (In general formula (1), R represents a hydroxyl group or an alkyl group with 1 to 3 carbon atoms. There may be multiple Rs that are the same or different.) Q represents a trivalent to hexavalent aliphatic group. X represents an alkyl group having 1 to 3 carbon atoms. Multiple Xs may be the same or different. (m represents an integer from 0 to 3, and n represents an integer from 1 to 6.) [3] As in [1] or [2], a conductive resin composition, wherein, The aliphatic epoxy compound (B) with three or more functions contains at least one of the compounds selected from those in general formula (1) where the aforementioned Q is an aliphatic group represented by general formulas (a) to (c). (In general formulas (a) to (c), * represents a bond.) [4] A conductive resin composition as described in any of [1] to [3], wherein, Silver-containing particles (A) include two or more types of silver-containing particles selected from spherical, dendritic, rope-like, scaly, aggregated, and polyhedral shapes. [5] The conductive resin composition of any one of [1] to [4] further contains a hardener (C). [6] The conductive resin composition of any of [1] to [5] also contains an organic solvent (D). [7] A high thermal conductivity material, which is obtained by sintering any one of the conductive resin compositions of [1] to [6]. [8] A semiconductor device comprising: Substrate; and A semiconductor device, which is mounted on the aforementioned substrate via an adhesive layer, and The aforementioned adhesive layer is formed by sintering any one of the conductive resin compositions in [1] to [6]. [9] A semiconductor device as described in [8], wherein the aforementioned bonding layer bonds the aforementioned substrate to the silicon or metal surface of the aforementioned semiconductor element. [Effects of the Invention]

[0011] According to the present invention, a conductive resin composition with excellent thermal conductivity and excellent storage modulus of elasticity or good adhesion to semiconductor elements and substrates can be provided. In other words, a conductive resin composition with an excellent balance of these properties can be provided. Simple Explanation of the Diagram

[0012] [Figure 1] is a schematic cross-sectional view of an example of a semiconductor device. [Figure 2] is a schematic cross-sectional view of an example of a semiconductor device. Implementation

[0013] Hereinafter, embodiments of the present invention will be described using drawings. Furthermore, in all drawings, the same symbols are used to denote the same constituent elements, and descriptions are omitted where appropriate.

[0014] In this specification, unless otherwise specified, the description of "a~b" in the description of numerical ranges means a or more and b or less. For example, "1~5% by mass" means "more than 1% by mass and less than 5% by mass".

[0015] In the description of groups (atomic groups) in this specification, the descriptions that do not specify "substituted" or "unsubstituted" include both "without substituents" and "with substituents". For example, "alkyl" includes not only alkyl without substituents (unsubstituted alkyl) but also alkyl with substituents (substituted alkyl). The use of "(meth)acrylic acid" in this specification indicates that it includes both acrylic acid and methacrylic acid. The same applies to similar descriptions of "(meth)acrylate," "(meth)acrylyl," etc.

[0016] The conductive resin composition of this embodiment contains (A) silver particles and (B) an aliphatic epoxy compound with three or more functions. The content of silver particles (A) can be set to 81% by mass or more, preferably 82% by mass or more, more preferably 83% by mass or more, further preferably 84% by mass or more, and especially preferably 85% by mass or more. This provides a conductive resin composition that exhibits excellent thermal conductivity, as well as excellent storage modulus of elasticity and good adhesion to semiconductor elements and substrates.

[0017] [Silver-containing particles (A)] Silver-containing particles (A) can be sintered through appropriate heat treatment to form a particle-linked structure (sintered structure).

[0018] In particular, by including silver particles in the conductive resin composition (especially by including silver particles with relatively small particle size and relatively large specific surface area), a sintered structure can be easily formed even when heat-treated at a relatively low temperature (around 180°C). A preferred particle size will be discussed later.

[0019] The shape of the silver-containing particles (A) is not particularly limited, and known shapes such as spherical, dendritic, rope-like, scale-like, aggregated, and polyhedral shapes can be cited. In this embodiment, it is possible to contain silver-containing particles of one or more such shapes, preferably two or more. By containing silver-containing particles of two or more such shapes, the contact rate between the silver-containing particles is increased, thus making it easier to form a network after sintering the conductive resin composition, further improving thermal conductivity and electrical conductivity. Furthermore, by controlling the orientation of the filler, the propagation of cracks generated within the conductive resin composition can be suppressed.

[0020] In this embodiment, it is preferable to contain two or more types of silver-containing particles selected from spherical, flake-like, aggregated, and polyhedral shapes; it is even more preferable to contain spherical silver-containing particles (a1) and one or more types of silver-containing particles selected from flake-like, aggregated, and polyhedral shapes (a2); and it is particularly preferable to contain both spherical silver-containing particles (a1) and flake-like silver-containing particles (a2-1). This further increases the contact rate between the silver-containing particles, making it easier to form a network after sintering the conductive resin composition, thus further improving thermal conductivity and electrical conductivity, and further enhancing impact resistance.

[0021] By using silver-containing particles (a2) in silver-containing particles (A), it is possible to suppress resin cracking in molded articles obtained from conductive resin compositions or to suppress the coefficient of linear expansion. Furthermore, in this embodiment, "spherical" is not limited to a perfect sphere, but also includes shapes with slight irregularities on the surface. Its roundness is, for example, 0.90 or higher, preferably 0.92 or higher, and even more preferably 0.94 or higher.

[0022] The surface of silver-containing particles (A) can also be treated with organic compounds such as carboxylic acids, saturated fatty acids with 4 to 30 carbon atoms, monovalent unsaturated fatty acids with 4 to 30 carbon atoms, and long-chain alkyl nitrile.

[0023] The silver-containing particle (A) can be (i) a particle that is essentially composed of only silver, or (ii) a particle composed of silver and other components besides silver. Furthermore, as a metal-containing particle, it can also be composed of both (i) and (ii).

[0024] In this embodiment, it is particularly preferred that the resin particles (A) contain silver-coated resin particles whose surfaces are coated with silver. This allows for the preparation of a conductive resin composition that yields a cured material with superior thermal conductivity and a low storage modulus of elasticity.

[0025] The surface of the silver-coated resin particles is silver, while the interior is resin, thus they are considered to have good thermal conductivity and are softer compared to particles composed solely of silver. Therefore, it is believed that by using silver-coated resin particles, it is easy to design the thermal conductivity or storage modulus to appropriate values.

[0026] Typically, increasing the amount of silver particles can improve thermal conductivity. However, due to the "hardness" of metals, excessive amounts of silver particles can sometimes result in an excessively high modulus of elasticity after sintering. By using silver-coated resin particles, some or all of which are silver particles, it is easy to design conductive resin compositions that can produce hardened products with the desired thermal conductivity or storage modulus of elasticity. In silver-coated resin particles, the silver layer only needs to cover at least a portion of the surface of the resin particles. Of course, the silver can also cover the entire surface of the resin particles.

[0027] Specifically, in silver-coated resin particles, it is preferable that the silver layer covers more than 50% of the surface of the resin particles, more preferably more than 75%, and even more preferably more than 90%. Most preferably, in silver-coated resin particles, the silver layer substantially covers the entire surface of the resin particles. As another perspective, when silver-coated resin particles are cut with a certain cross-section, it is better to confirm that the silver layer can be confirmed around that cross-section.

[0028] As another point of view, the mass ratio of resin to silver in the silver-coated resin particles is, for example, 90 / 10 to 10 / 90, preferably 80 / 20 to 20 / 80, and even more preferably 70 / 30 to 30 / 70.

[0029] Examples of "resin" used in silver-coated resin particles include polysiloxane resin, (meth)acrylic resin, phenolic resin, polystyrene resin, melamine resin, polyamide resin, and polytetrafluoroethylene resin. Of course, other resins may also be used. Furthermore, there may be only one type of resin, or two or more types of resin may be used together. From the perspective of elasticity and heat resistance, polysiloxane or (meth)acrylic resins are preferred.

[0030] Polysiloxanes can be particles composed of organopolysiloxanes, which are obtained by polymerizing organochlorosilanes such as methylchlorosilane, trimethyltrichlorosilane, and dimethyldichlorosilane. Alternatively, they can be polysiloxanes with a basic framework consisting of a structure formed by further three-dimensional cross-linking of organopolysiloxanes.

[0031] (Meth)acrylate resin can be a resin obtained by polymerizing a monomer containing (meth)acrylate as a main component (50% by weight or more, preferably 70% by weight or more, more preferably 90% by weight or more). Examples of (meth)acrylates include, for example, at least one compound selected from the group consisting of methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, stearyl methacrylate, cyclohexyl methacrylate, 2-hydroxyethyl methacrylate, 1,4-cyclohexanediol mono(meth)acrylate, 2-propyl methacrylate, chloro-2-hydroxyethyl methacrylate, diethylene glycol mono(meth)acrylate, methoxyethyl methacrylate, glycidyl methacrylate, dicyclopentyl methacrylate, dicyclopentenyl methacrylate, and isoborneol methacrylate. Furthermore, the monomer components of acrylic resins may contain small amounts of other monomers. Examples of such other monomer components include styrene monomers. For information on silver-coated (meth)acrylic resins, please also refer to Japanese Patent Application Publication No. 2017-126463.

[0032] Various functional groups can be introduced into polysiloxane or (meth)acrylic resins. There are no particular limitations on the functional groups that can be introduced. Examples include epoxy, amino, methoxy, phenyl, carboxyl, hydroxyl, alkyl, vinyl, and mercapto groups.

[0033] The resin particle portion of silver-coated resin particles can contain various additives, such as low-stress modifiers. Examples of low-stress modifiers include butadiene-styrene rubber, butadiene-acrylonitrile rubber, polyurethane rubber, polyisoprene rubber, acrylic rubber, fluororubber, liquid organopolysiloxanes, liquid polybutadiene, and other liquid synthetic rubbers. In particular, when the resin particle portion contains polysiloxane, the inclusion of a low-stress modifier can improve the elastic properties of the silver-coated resin particles.

[0034] The shape of the resin particles in the silver-coated resin particles is not particularly limited. A combination of spherical and other irregular shapes, such as flat, plate-like, needle-like, etc., is preferred.

[0035] There is no particular limitation on the specific gravity of the silver-coated resin particles, but the lower limit is, for example, 2 or more, preferably 2.5 or more, and even more preferably 3 or more. The upper limit is, for example, 10 or less, preferably 9 or less, and even more preferably 8 or less. Considering the dispersibility of the silver-coated resin particles themselves, or the uniformity when combined with silver-coated resin particles and other silver-containing particles, an appropriate specific gravity is preferable.

[0036] When using silver-coated resin particles, the proportion of silver-coated resin particles in the total silver-particle-containing (A) is preferably 1 to 50% by mass, more preferably 3 to 45% by mass, and even more preferably 5 to 40% by mass. By appropriately adjusting this proportion, heat dissipation can be further improved while suppressing the reduction in adhesion caused by thermal cycling.

[0037] Incidentally, if the proportion of silver-coated resin particles in the whole of silver-containing particles (A) is not 100% by mass, the silver-containing particles other than the silver-coated resin particles are, for example, particles that are substantially composed of only silver.

[0038] The median particle size D50 of the silver-containing particles (A) is, for example, 0.01~50 μm, preferably 0.1~20 μm, and more preferably 0.5~10 μm. By setting D50 to an appropriate value, it is easy to maintain a balance between thermal conductivity, sinterability, and resistance to thermal cycling. Furthermore, by setting D50 to an appropriate value, it is sometimes possible to improve the workability of coating / adhesion. The particle size distribution of silver-containing particles (horizontal axis: particle size, vertical axis: frequency) can be unimodal or multimodal.

[0039] From the viewpoint of the effects of the present invention, it is preferable that the silver-containing particles (a) contain spherical silver-containing particles (a1) and scaly silver-containing particles (a2-1). These silver-containing particles are more preferably silver particles composed substantially only of silver.

[0040] The median particle size D50 of the spherical silver-containing particles (a1) is, for example, 0.1~20 μm, preferably 0.5~10 μm, and more preferably 0.5~5.0 μm. The specific surface area of ​​the spherical silver-containing particles (a1) is, for example, 0.1~2.5 m² / g, preferably 0.5~2.3 m² / g, and more preferably 0.8~2.0 m² / g. The tap density of the spherical silver-containing particles (a1) is, for example, 1.5~6.0 g / cm3, preferably 2.5~5.8 g / cm3, and more preferably 4.5~5.5 g / cm3. The spherical silver-containing particles (a1) have a sphericality of 0.90 or higher, preferably 0.92 or higher, and even more preferably 0.94 or higher. By satisfying these various characteristics, it achieves an excellent balance of thermal conductivity, sinterability, and resistance to thermal cycling.

[0041] The median particle size D50 of the scaly silver-containing particles (a2-1) is, for example, 0.1~20 μm, preferably 1.0~15 μm, and more preferably 2.0~10 μm. The specific surface area of ​​the scaly silver-containing particles (a2-1) is, for example, 0.1~2.5 m² / g, preferably 0.2~2.0 m² / g, and more preferably 0.25~1.2 m² / g. The tap density of the scaly silver-containing particles (a2-1) is, for example, 1.5~6.0 g / cm3, preferably 2.5~5.9 g / cm3, and more preferably 4.0~5.8 g / cm3. By satisfying these various characteristics, it achieves an excellent balance of thermal conductivity, sinterability, and resistance to thermal cycling.

[0042] In this embodiment, by combining at least one spherical silver-containing particle (a1) that satisfies the above-mentioned characteristics and at least one scale-shaped silver-containing particle (a2-1) that satisfies the above-mentioned characteristics, the thermal conductivity and electrical conductivity are particularly improved.

[0043] The ratio of the content of spherical silver-containing particles (a1) to the content of flake-shaped silver-containing particles (a2-1) (a1 / a2-1) is preferably 0.1 or more and 10 or less, more preferably 0.3 or more and 5 or less, further preferably 0.5 or more and 3 or less, and particularly preferably 0.7 or more and 2 or less. This significantly increases the contact rate between the silver-containing particles, making it easier to form a network after sintering the paste-like polymeric composition, thus improving thermal and electrical conductivity.

[0044] The ratio (a1 / a2-1) of the median particle size D50 of the spherical silver-bearing particles (a1) to the median particle size D50 of the scaly silver-bearing 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, and even more preferably 0.07 or more and 0.3 or less. In this way, since the spherical silver-containing particles are efficiently filled in the gaps between the scaly silver-containing particles, the contact rate between the silver-containing particles is particularly improved. Therefore, after sintering, the paste-like polymeric composition is easy to form a network, and the thermal conductivity and electrical conductivity are particularly improved.

[0045] The ratio of the tap density of spherical silver-containing particles (a1) to the tap density of scaly silver-containing particles (a2-1) (a1 / a2-1) is preferably 0.5 or more and 2.0 or less, and more preferably 0.7 or more and 1.2 or less. As a result, the increased filling rate of silver particles leads to a particularly high contact rate between them, making it easier to form a network after sintering the paste-like polymeric composition, thus significantly improving thermal and electrical conductivity.

[0046] The median particle size D50 of the silver-coated resin particles is, for example, 5.0~25 μm, preferably 7.0~20 μm, and more preferably 8.0~15 μm. This further improves thermal conductivity.

[0047] The median particle size D50 of the silver-containing particles (A) can be determined, for example, by particle image measurement using the FPIA (registered trademark)-3000 flow particle image analyzer manufactured by Sysmex Corporation. More specifically, the particle size of the silver-containing particles (A) can be determined by using this device to measure the median particle size on a wet volume basis.

[0048] Silver-containing particles (A) that are essentially composed solely of silver can be obtained, for example, from DOWA HIGHTECH CO.,LTD., Fukuda Metal Foil & Powder Co.,Ltd. Similarly, silver-coated resin particles can be obtained, for example, from Mitsubishi Materials Corporation, Sekisui Chemical Co.,Ltd., Sanno Co.,Ltd.

[0049] From the viewpoint of the effects of the present invention, the proportion of silver-containing particles (A) in the conductive resin composition of this embodiment is preferably 70-98% by mass, more preferably 75-95% by mass, and even more preferably 80-92% by mass.

[0050] [Aliphatic epoxy compounds with 3 or more functions (B)] The aliphatic epoxy compound (B) with three or more functions contains at least one compound selected from those represented by the following general formula (1).

[0051] The aliphatic epoxy compound (B) with three or more functions contains a compound represented by the following general formula (1) that has a plurality of 3- to 6-valent aliphatic groups bonded by epoxy groups. This results in excellent reactivity and increased crosslinking density. Therefore, by promoting the sintering of silver-containing particles through the hardening shrinkage during resin formation from this compound, a high thermal conductivity material with excellent thermal conductivity can be obtained. Furthermore, the obtained cured material (high thermal conductivity material) has a low elastic modulus and excellent flexibility, thus semiconductor devices containing this cured material exhibit excellent product reliability due to stress relief. Furthermore, the obtained cured material (high thermal conductivity material) also exhibits excellent adhesion to semiconductor elements or substrates, resulting in excellent product reliability. In other words, a conductive resin composition that provides a good balance of these properties is achieved.

[0052]

[0053] In general formula (1), R represents a hydroxyl group or an alkyl group having 1 to 3 carbon atoms, preferably a hydroxyl group or an alkyl group having 1 to 2 carbon atoms, and even more preferably a hydroxyl group or an alkyl group having 1 carbon atom. There may be multiple Rs that are the same or different.

[0054] X represents an alkyl group having 1 to 3 carbon atoms, preferably an alkyl group having 1 to 2 carbon atoms, and more preferably an alkyl group having 1 carbon atom. Multiple X's may be the same or different.

[0055] m represents an integer from 0 to 4, preferably an integer from 0 to 3, and even more preferably an integer from 0 to 2. n represents an integer from 1 to 6, preferably an integer from 2 to 6, and even more preferably an integer from 2 to 4. Q represents a trivalent to hexavalent aliphatic group, preferably a trivalent to hexavalent aliphatic group.

[0056] As the aforementioned aliphatic group with a 3 to 6 valence in Q, known aliphatic groups can be used within the scope of the effects of the present invention, for example, aliphatic groups represented by the following general formulas (a) to (c).

[0057]

[0058] Examples of compounds containing an aliphatic group of formula (a) as Q in general formula (1) include DENACOL EX-321 (manufactured by Nagase ChemteX Corporation) and PETG (manufactured by SHOWA DENKO KK). Compounds containing an aliphatic group of general formula (b) as Q in general formula (1) can be cited as examples such as DENACOL EX-313 (manufactured by Nagase ChemteX Corporation). Compounds containing an aliphatic group of formula (c) as Q in general formula (1) include DENACOL EX-614B (manufactured by Nagase ChemteX Corporation). In general formulas (a) to (c), * represents a bond.

[0059] From the viewpoint of the effects of the present invention, it is preferable that the aliphatic epoxy compound (B) with three or more functions contains at least one of the compounds in which Q is represented by aliphatic groups of general formula (a), (b) and (c), and it is even more preferable that it contains at least one of the compounds in which Q is represented by aliphatic groups of general formula (a).

[0060] From the viewpoint of the effects of the present invention, the proportion of aliphatic epoxy compounds (B) with three or more functions in the conductive resin composition of this embodiment is preferably 1 to 25% by mass, more preferably 2 to 20% by mass, and even more preferably 3 to 15% by mass.

[0061] [Cardizing agent (C)] The conductive resin composition of this embodiment may further contain a hardener (C). As a curing agent (C), examples include curing agents having reactive groups that react with the epoxy groups contained in the polyfunctional epoxy compound (C).

[0062] The curing agent (C) is preferably a phenolic curing agent. Such curing agents are particularly preferred when the thermosetting component contains epoxy groups. Phenolic curing agents can be low-molecular-weight compounds or high-molecular-weight compounds (i.e., phenolic resins).

[0063] Examples of low-molecular-weight phenolic curing agents include: bisphenol A, bisphenol F (dihydroxydiphenylmethane), and other bisphenol compounds (phenolic resins with a bisphenol F skeleton); compounds with a phenyl skeleton such as 4,4'-bisphenol.

[0064] Specifically, examples of phenolic resins include: phenolic varnish resins such as phenol-formaldehyde varnish resins, cresol-formaldehyde varnish resins, bisphenol-formaldehyde varnish resins, and phenol-biphenyl varnish resins; polyvinylphenol; triphenylmethane-type phenolic resins; terpene-modified phenolic resins and dicyclopentadiene-modified phenolic resins; and phenolic aralkyl resins with a phenyl backbone and / or a phenyl-linked backbone, and naphthol aralkyl resins with a phenyl backbone and / or a phenyl-linked backbone. When using hardener (C), only one type can be used, or two or more types can be used together.

[0065] When the conductive resin composition of this embodiment contains a curing agent (C), when the amount of the aliphatic epoxy compound (B) with three or more functions is set to 100 parts by mass, the amount is preferably 10 to 120 parts by mass, and more preferably 20 to 80 parts by mass.

[0066] [Organic Solvent (D)] The conductive resin composition of this embodiment may further contain an organic solvent (D). Examples of organic solvents (D) include: methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 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, methyl methoxybutanol, α-terpineol, β-terpineol, hexanediol, benzyl alcohol, 2-phenylethanol, isopalmitoyl alcohol, isostearyl alcohol, lauryl alcohol, ethylene glycol, propylene glycol, butyl glycerol, glycerol, and other alcohols. Ketones such as 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), and diisobutyl ketone (2,6-dimethyl-4-heptanone); Esters such as ethyl acetate, butyl acetate, diethyl phthalate, dibutyl phthalate, acetoxyethane, methyl butyrate, methyl hexanoate, methyl octanoate, methyl decanoate, methyl methyl acetate, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, 1,2-diacetoxyethane, tributyl phosphate, tricresyl phosphate, and tripentyl phosphate; Ethers such as 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, and 1,2-bis(2-methoxyethoxy)ethane; Acetic acid, 2-(2-butoxyethoxy)ethane, and other ester ethers; 2-(2-methoxyethoxy)ethanol and other ether alcohols; Hydrocarbons such as toluene, xylene, n-alkanes, isoalkanes, dodecylbenzene, turpentine, kerosene, and light oil; Nitriles such as acetonitrile or propionitrile; Acetamides such as acetamide, N,N-dimethylmethamide, and N-methylpyrrolidone; Lactones such as γ-butyrolactone, γ-valerolactone, and δ-valerolactone; Low molecular weight volatile silicone oils, volatile organic modified silicone oils, and other silicone oil types; Monofunctional (meth)acrylic acid compounds, etc. When using organic solvents (D), one solvent may be used alone, or two or more solvents may be used together.

[0067] When using organic solvent (D), there is no particular limitation on its amount. The amount used can be adjusted appropriately according to the desired flowability, etc. As an example, organic solvent (D) is used in an amount where the concentration of the non-volatile component of the conductive resin composition is 50-95% by mass.

[0068] [Other ingredients] The conductive resin composition of this embodiment may contain epoxy resin, difunctional epoxy compound, curing accelerator, silane coupling agent, plasticizer, adhesion promoter, etc. as other components.

[0069] Examples of epoxy resins include aromatic epoxy resins, such as bisphenol A type epoxy resin, brominated bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AF type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, fumonisin type epoxy resin, phenolic varnish type epoxy resin, phenolic varnish type epoxy resin, o-cresol phenolic varnish type epoxy resin, dicyclopentadiene type epoxy resin, bisphenol A-polyethylene oxide type epoxy resin, fumonisin type epoxy resin, tris(hydroxyphenyl)methane type epoxy resin, and tetraphenylethane type epoxy resin, as well as epoxypropyl ether type epoxy resin and epoxypropylamine type epoxy resin. In addition, examples include epoxy propylene oxide type epoxy resins obtained by condensation of epichlorohydrin with phthalic acid derivatives and carboxylic acids such as fatty acids, as well as epoxy resins modified by various methods. The conductive resin composition of this embodiment may contain less than 1% by mass of the aforementioned epoxy resin.

[0070] Examples of the aforementioned difunctional epoxy compounds include: bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, bisphenol AF diglycidyl ether, bisphenol acetophenone diglycidyl ether, bisphenol trimethylcyclohexane diglycidyl ether, bisphenol benzoyl diglycidyl ether, tetramethylbisphenol A diglycidyl ether, tetramethylbisphenol F diglycidyl ether, tetramethyltributylbisphenol A diglycidyl ether, tetramethylbisphenol S diglycidyl ether, and other bisphenol-based diglycidyl compounds. Ethers; ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,5-pentanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, 1,7-heptanediol diglycidyl ether, 1,8-octanediol diglycidyl ether, 1,10-decanediol diglycidyl ether, 2,2-dimethyl-1,3-propanediol diglycidyl ether, and other alkyl glycol diglycidyl ethers; trimethylolpropane diglycidyl ether, etc.

[0071] By including silane coupling agents, adhesion can be further improved, and by including plasticizers, the storage modulus of elasticity can be reduced. Furthermore, it is easier to further suppress the decrease in adhesion caused by thermal cycling.

[0072] <Conductive Resin Composition> The conductive resin composition of this embodiment is preferably in a paste form at 20°C. That is, the conductive resin composition (paste composition) of this embodiment is preferably able to be coated onto a substrate or the like like a paste at 20°C. Therefore, the conductive resin composition of this embodiment can be preferably used as an adhesive for semiconductor devices. Of course, depending on the manufacturing process used, the conductive resin composition of this embodiment may also be a relatively low viscosity varnish or the like. The conductive resin composition of this embodiment can be obtained by mixing the above-mentioned components and other components as needed using conventional methods.

[0073] From the viewpoint of the effects of the present invention, the conductive resin composition (100% by mass) of this embodiment can contain silver particles (A) in an amount of preferably 70-98% by mass, more preferably 75-95% by mass, and even more preferably 80-92% by mass. It can contain an aliphatic epoxy compound (B) with three or more functions in an amount of preferably 1 to 25% by mass, more preferably 2 to 20% by mass, and even more preferably 3 to 15% by mass. Furthermore, it is preferable that the silver particles (A) contain both spherical silver particles (a1) and flaky silver particles (a2-1), and the ratio of the content of spherical silver particles (a1) to the content of flaky silver particles (a2-1) (a1 / a2-1) is preferably 0.1 or more and 10 or less, more preferably 0.3 or more and 5 or less, further preferably 0.5 or more and 3 or less, and especially preferably 0.7 or more and 2 or less. In the case where the conductive resin composition of this embodiment further contains a curing agent (C), when the amount of the aliphatic epoxy compound (B) with three or more functions is set to 100 parts by mass, the amount is preferably 10 to 120 parts by mass, and more preferably 20 to 80 parts by mass.

[0074] High thermal conductivity materials A material with high thermal conductivity can be obtained by sintering the conductive resin composition of this embodiment. By changing the shape of highly thermally conductive materials, they can be applied to various parts in the automotive and motor industries that require heat dissipation.

[0075] Semiconductor Devices Semiconductor devices can be manufactured using the conductive resin composition of this embodiment. For example, semiconductor devices can be manufactured by using the conductive resin composition of this embodiment as an "adhesive" between a substrate and a semiconductor element.

[0076] In other words, the semiconductor device of this embodiment includes, for example, a substrate and a semiconductor element, wherein an adhesive layer obtained by sintering the conductive resin composition by heat treatment is mounted on the substrate.

[0077] In the semiconductor device of this embodiment, stress is mitigated, and even thermal cycling does not easily reduce the adhesion of the bonding layer. In other words, the semiconductor device of this embodiment has high reliability. Examples of semiconductor components include ICs, LSIs, power semiconductor components (power semiconductors), and various other components. Examples of substrates include various semiconductor wafers, lead frames, BGA substrates, mounting substrates, heat spreaders, and heat sinks.

[0078] The following illustrations illustrate an example of a semiconductor device. Figure 1 is a cross-sectional view showing an example of a semiconductor device. The semiconductor device 100 includes: a substrate 30; and a semiconductor element 20, which is mounted on the substrate 30 via an adhesive layer 10 (wafer adhesive) of a heat-treated body composed of a conductive resin.

[0079] The semiconductor element 20 is electrically connected to the substrate 30, for example, via a bonding wire 40. Furthermore, the semiconductor element 20 is sealed, for example, with a sealing resin 50.

[0080] It is preferable that the thickness of the next layer 10 is 5 μm or more, more preferably 10 μm or more, and even more preferably 20 μm or more. This improves the stress absorption capacity of the conductive resin composition and enhances its resistance to thermal cycling. The thickness of layer 10 is, for example, less than 100 μm, preferably less than 50 μm.

[0081] In Figure 1, the substrate 30 is, for example, a lead frame. At this time, the semiconductor element 20 is mounted on the die pad 32 or the substrate 30 via the bonding layer 10. Furthermore, the semiconductor element 20 is electrically connected to the external lead 34 (substrate 30) via, for example, bonding wires 40. The substrate 30, serving as the lead frame, is, for example, made of alloy 42, a Cu frame, etc.

[0082] The substrate 30 can be an organic substrate or a ceramic substrate. Examples of organic substrates include those made of epoxy resin, cyanate ester resin, and maleic anhydride resin. The surface of the substrate 30 may be coated with a metal such as silver or gold. This improves the adhesion between the adhesive layer 10 and the substrate 30. The surface of the semiconductor element 20 that contacts the bonding layer 10 can be a silicon surface, a metal vapor-deposited surface, or a metal-plated surface. Examples of metal vapor-deposited surfaces include gold-plated or silver-plated surfaces, and examples of metal-plated surfaces include gold-plated or silver-plated surfaces. The conductive resin composition of this embodiment exhibits excellent adhesion to semiconductor elements and substrates, even on silicon surfaces.

[0083] Figure 2 is a cross-sectional view of an example of a semiconductor device 100 that is different from that in Figure 1. In the semiconductor device 100 of FIG2, the substrate 30 is, for example, an interposer. A plurality of solder balls 52 are formed on the side of the substrate 30 that is opposite to the side on which the semiconductor element 20 is mounted. At this time, the semiconductor device 100 is connected to other wiring substrates via the solder balls 52.

[0084] An example of a method for manufacturing a semiconductor device will be explained. First, a conductive resin composition is coated onto a substrate 30, and then a semiconductor element 20 is disposed thereon. That is, the substrate 30, the conductive resin composition, and the semiconductor element 20 are sequentially laminated. There are no particular limitations on the method for coating conductive resin compositions. Specifically, methods such as dispensing, printing, and inkjet printing can be cited.

[0085] Next, the conductive resin composition is thermosetting. It is preferable to perform thermosetting by pre-curing and post-curing. Through thermosetting, the conductive resin composition becomes a heat-treated body (cured material). Through thermosetting (heat treatment), the metal-containing particles in the conductive resin composition agglomerate, forming a structure in the adhesive layer 10 where the interfaces between multiple metal-containing particles disappear. Herein, the substrate 30 and the semiconductor element 20 are bonded via the adhesive layer 10. Next, the semiconductor element 20 is electrically connected to the substrate 30 using bonding wires 40. Then, the semiconductor element 20 is sealed with sealing resin 50. In this way, a semiconductor device can be manufactured.

[0086] The embodiments of the present invention have been described above, but these are merely examples of the present invention, and various configurations other than those described above can be used. Furthermore, the present invention is not limited to the above embodiments, and modifications and improvements within the scope of achieving the objectives of the present invention are all included in the present invention. [Example]

[0087] The present invention will be further described in detail below with reference to embodiments, but the present invention is not limited thereto. The ingredients used in the examples are shown below.

[0088] (Epoxy resin) • Epoxy Resin 1: Bisphenol F type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., RE-303S)

[0089] (Aliphatic epoxy compounds with 3 or more functions) • Aliphatic epoxy compound 1: Trimethylolpropane polyoxypropylene ether (a mixture of compounds represented by the following chemical formula, DENACOL EX-321L, manufactured by Nagase ChemteX Corporation)

[0090] • Aliphatic epoxy compound 2: The product of the epoxidation reaction of neopentyl tetraallyl ether and hydrogen peroxide (a compound represented by the following chemical formula, manufactured by Show Free PETG and SHOWA DENKO KK).

[0091] ((meth)acrylic acid compound) • Acrylic monomer 1: Ethylene glycol dimethacrylate (manufactured by Kyoisha Chemical Co., Ltd., Light Ester EG)

[0092] (hardener) • Hardener 1: Phenolic resin with a bisphenol F backbone (manufactured by DIC Corporation, DIC-BPF)

[0093] (Free radical polymerization initiator) • Free radical polymerization initiator 1: Diisopropylphenyl peroxide (manufactured by Kayaku Akzo Corporation, Perkadox BC)

[0094] (hardening accelerator) • Hardening accelerator 1: 2-Phenyl-1H-imidazol-4,5-diethanol (manufactured by Shikoku Chemicals Corporation, 2PHZ-PW)

[0095] (Contains silver particles) • Silver filler 1: Manufactured by DOWA Electronics Materials Co., Ltd., AG-DSB-114, spherical, median particle size D 50: 0.7μm, specific surface area: 1.05m² / g, tap density: 5.25g / cm³, sphericity: 0.953 • Silver Filler 2: Manufactured by Fukuda Metal Foil & Powder Co., Ltd., HKD-12, flaky, median particle size D50: 7.6μm, specific surface area: 0.315m² / g, tap density: 5.5g / cm³

[0096] (solvent) Solvent 1: Tripropylene glycol monobutyl ether (BFTG, manufactured by NIPPON NYUKAZAI CO., LTD., boiling point 274°C)

[0097] [Examples 1-5, Comparative Examples 1-2] Based on the blending amounts shown in Table 1, the raw material components were mixed to obtain the varnish. Next, the obtained varnish was mixed according to the proportions shown in Table 1 and kneaded at room temperature using a three-roll mill. This produced a conductive resin composition.

[0098] (Volume resistivity) A conductive resin composition was coated onto a glass plate, and the plate was heated from 30°C to 200°C over a nitrogen atmosphere for 60 minutes, followed by heat treatment at 200°C for 120 minutes. This yielded a heat-treated body (cured body) with a conductive resin composition thickness of 0.05 mm. The surface resistance of the heat-treated body was measured using a DC four-electrode method based on a milliohm meter (manufactured by HIOKI EE CORPORATION) with electrodes spaced 40 mm apart.

[0099] (Storage elasticity modulus) The heat-treated body, composed of a conductive resin, was cut into strips approximately 0.1 mm × 10 mm × 4 mm to obtain elongated samples for evaluation. Using these samples, the storage modulus (E') at 25 °C was measured by DMA (Dynamic Viscoelasticity Measurement, Tensile Mode) at a heating rate of 5 °C / min and a frequency of 10 Hz.

[0100] (Seam strength after constant temperature moisture absorption treatment (Au wafer)) A predetermined amount of the obtained conductive resin composition was coated onto the Ag-plated Ag of a Cu leadframe. A 5×7 mm square Au-coated wafer was then mounted on the leadframe in an Au-coated facet contact manner. The wafer was then cured at 200°C for 2 hours under nitrogen atmosphere to produce an evaluation semiconductor device. After the obtained semiconductor device was treated at 60°C and 60% humidity for 48 hours, the wafer bonding strength was evaluated using a 4000 universal bonding tester (manufactured by Nordson Dage). The strength of the wafer bonding was measured by shearing at a position 50 μm above the leadframe at a tool speed of 500 μm / s while heated to 260°C.

[0101] (Evaluation of whether peeling occurs after constant temperature moisture absorption treatment (Au wafer)) The evaluation semiconductor devices prepared in the above-described manner were evaluated using an ultrasonic flaw detector (SAT) after being treated for 48 hours at 60°C and 60% humidity, in the same manner as described above. Devices found to have peeled were marked with ×, and devices that did not peel were marked with ○.

[0102] (Adhesion strength after constant temperature moisture absorption treatment (silicon wafer)) Using unplated metal silicon wafers, silicon wafers were mounted on a coated conductive resin composition in a silicon-surface contact manner. Otherwise, the adhesion strength after constant temperature moisture absorption treatment was measured in the same manner as described above.

[0103] (Evaluation of whether delamination occurs after constant temperature and moisture absorption treatment (silicon wafer)) Using unplated 7×7mm square silicon wafers, the presence or absence of peeling after isothermal moisture absorption treatment was evaluated in the same manner as described above.

[0104] [Table 1] Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Composition Epoxy resin Epoxy Resin 1 Quality 50.0 50.0 3 or more functions Aliphatic epoxy compounds Aliphatic epoxide 1 50.0 50.0 50.0 50.0 40.0 Aliphatic epoxy compounds 2 10.0 (meth)acrylic acid compounds acrylic monomer 1 20.0 hardener Hardener 1 20.0 20.0 20.0 20.0 20.0 20.0 free radical polymerization initiators Free radical polymerization initiator 1 2.5 hardening accelerator Hardening accelerator 1 1.0 1.5 2.0 2.0 1.0 1.0 1.0 total Quality 71.0 71.5 72.0 52.0 71.0 93.5 71.0 electrical conductivity resin composition Composition The above-mentioned components Quality 10.6 10.6 10.6 10.6 10.6 10.6 10.6 Silver particles Silver filler 1 45.0 45.0 45.0 45.0 45.0 45.0 45.0 Silver filler 2 40.0 40.0 40.0 40.0 40.0 40.0 40.0 solvent Solvent 1 4.4 4.4 4.4 4.4 4.4 4.4 4.4 total Quality 100.0 100.0 100.0 100.0 100.0 100.0 100.0 Volume resistivity μΩ·cm 11.2 11.1 11.0 10.7 10.4 10.8 12.4 Storage elasticity modulus (E') GPa 15 15 16 10 15 20 17 Adhesion strength after constant temperature moisture absorption treatment (Au wafer) N / mm 2 1.63 1.60 1.49 1.74 1.51 0.94 1.17 Does the Au wafer peel off after constant temperature and moisture absorption treatment? determination ○ ○ ○ ○ ○ × × Adhesion strength after constant temperature moisture absorption treatment (silicone wafer) N / mm 2 2.88 3.61 3.71 3.08 4.57 1.49 1.08 Did the silicon wafer peel off after the constant temperature and moisture absorption treatment? determination ○ ○ ○ ○ ○ × ×

[0105] As shown in Table 1, the cured material obtained from a conductive resin composition containing aliphatic epoxy compounds with three or more functions and a specified amount of silver particles has low volume resistivity and excellent thermal conductivity. Furthermore, it has a low storage modulus of elasticity and the stress is mitigated. As a result, even after a constant temperature moisture absorption test, the adhesion strength relative to the silicon or metal surface is high and peeling is suppressed. Therefore, semiconductor devices and the like with the cured material have excellent reliability. In other words, the balance of these properties is excellent.

[0106] This application claims priority based on Japanese Patent Application No. 2021-110818 filed on July 2, 2021 and Japanese Patent Application No. 2021-163530 filed on October 4, 2021, the entire contents of which are incorporated herein by reference.

[0107] 100: Semiconductor devices 10: Next layer 20: Semiconductor components 30: Substrate 32: Chip Pad 34: External lead wire 40: Joint line 50: Sealing resin 52: Welding ball

Claims

1. A conductive resin composition for wafer adhesive, comprising: (A) silver particles; and (B) an aliphatic epoxy compound with three or more functions, wherein the content of silver particles (A) is 85% by mass or more, and the silver particles (A) consists only of silver particles.

2. The conductive resin composition for the wafer adhesive as described in claim 1, wherein, The aliphatic epoxy compound (B) with three or more functions contains at least one compound selected from the compounds represented by the following general formula (1), in which R represents a hydroxyl group or an alkyl group having 1 to 3 carbon atoms, and there may be multiple Rs that are the same or different, Q represents an aliphatic group with 3 to 6 valences, X represents an alkyl group having 1 to 3 carbon atoms, and there may be multiple Xs that are the same or different, m represents an integer from 0 to 3, and n represents an integer from 3 to 6.

3. The conductive resin composition used for the wafer adhesive as described in claim 1 or 2, wherein, The aliphatic epoxy compound (B) with 3 or more functions contains at least one of the compounds selected from the general formula (1) in which the aforementioned Q is an aliphatic group represented by general formulas (a) to (c), where * represents a bond.

4. The conductive resin composition used for the wafer adhesive as described in claim 1 or 2, wherein, Silver particles include two or more types selected from spherical, dendritic, rope-like, scale-like, aggregated, and polyhedral shapes.

5. A conductive resin composition for the wafer adhesive as described in claim 1 or 2, wherein, Silver particles include spherical silver particles and scaly silver particles.

6. The conductive resin composition for wafer adhesive as claimed in claim 1 or 2 further contains a hardener (C).

7. The conductive resin composition for wafer adhesive as described in claim 1 or 2 further contains an organic solvent (D).

8. A high thermal conductivity material obtained by sintering the wafer adhesive of any one of claims 1 to 7 with a conductive resin composition.

9. A semiconductor device comprising: a substrate; and a semiconductor element mounted on the substrate via an adhesive layer, wherein the adhesive layer is formed by sintering a wafer adhesive material of any one of claims 1 to 7 with a conductive resin composition.

10. The semiconductor device as claimed in claim 9, wherein, The aforementioned adhesive layer bonds the aforementioned substrate to the silicon or metal surface of the aforementioned semiconductor device.

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