Metal pastes and electronic devices

Abstract

This invention provides a metal paste with an improved balance of performance characteristics, including low modulus of elasticity, low curing shrinkage, and high thermal conductivity. [Solution] A metal paste containing metal particles, comprising an allyl resin having a polyoxyalkylene skeleton structure and having allyl groups at one or both ends.

Description

Technical Field

[0001] The present invention relates to a metal paste and an electronic device.

Background Art

[0002] For the purpose of enhancing heat dissipation in an electronic device, a resin composition containing metal particles has been used. As a technique related to a resin composition having thermal conductivity, for example, the technique described in Patent Document 1 can be cited.

[0003] Patent Document 1 provides a semiconductor device obtained by bonding a semiconductor element with a thermally conductive adhesive sheet, which is a thermally conductive adhesive sheet formed by molding a resin composition containing (A) silver particles, (B) a thermosetting resin, and (C) a binder resin into a sheet shape. The (A) silver particles are secondary particles in which particles containing primary particles with an average particle diameter of 10 to 100 nm are aggregated. A thermally conductive adhesive sheet characterized by this is described.

Prior Art Documents

Patent Documents

[0004]

Patent Document ①

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present invention provides a metal paste with improved performance balance of low elastic modulus, low curing shrinkage, and high thermal conductivity.

Means for Solving the Problems

[0006] The inventors of the present invention have intensively studied to achieve the above problems. As a result, they have found that by including an allyl resin having a specific structure, it is possible to improve the performance balance of low elastic modulus, low curing shrinkage, and high thermal conductivity, and thus completed the present invention.

[0007] According to the present invention, there are provided a metal paste and an electronic device as described below.

[0008] [1] A metal paste containing metal particles, which contains an allyl resin having a polyoxyalkylene skeleton structure and having allyl groups at one or both ends. [2] The metal paste according to [1] above, wherein the allyl resin contains a compound represented by the following general formula (1). CH2=CHCH2O-(C m H 2m O) n -R (1) (In the above general formula (1), m represents an integer of 1 or more and 5 or less, n represents an integer of 1 or more and 10 or less, and R represents a hydrogen atom or an organic group having 1 to 5 carbon atoms.) [3] The metal paste according to [2] above, wherein R in the general formula (1) is an allyl group. [4] The metal paste according to [2] or [3] above, wherein m in the general formula (1) is 1 or more and 3 or less. [5] The metal paste according to any one of [2] to [4] above, wherein n in the general formula (1) is 3 or more and 6 or less. [6] The metal paste according to any one of [1] to [5] above, wherein the weight average molecular weight of the allyl resin in terms of polystyrene is 300 or more and 2000 or less. [7] The metal paste according to any one of [1] to [6] above, wherein the content of the allyl resin is 0.1% by mass or more and 5.0% by mass or less when the total solid content of the metal paste is 100% by mass. [8] The metal paste according to any one of the above [1] to [7], wherein the above metal particles include one or more selected from the group consisting of silver particles, silver-coated particles, gold particles, platinum particles, palladium particles, copper particles, nickel particles, and alloy particles thereof. [9] The average particle size (D) in the volume-based particle size distribution of the above metal particles as measured by laser diffraction scattering particle size distribution analysis. 50 A metal paste according to any of the above [1] to [8], wherein the thickness is 0.1 μm or more and 100 μm or less.

[10] The metal paste according to any of [1] to [9] above, wherein the content of the metal particles is 50% by mass or more and 99% by mass or less when the total solid content of the metal paste is considered to be 100% by mass.

[11] A metal paste according to any of [1] to

[10] above, further comprising a thermosetting resin (excluding the allyl resin mentioned above).

[12] The metal paste according to

[11] above, wherein the thermosetting resin includes an epoxy resin.

[13] The metal paste according to

[12] above, wherein the epoxy resin comprises one or more selected from the group consisting of bisphenol-type epoxy resin, phenol novolac-type epoxy resin, cresol novolac-type epoxy resin, and biphenyl-type epoxy resin.

[14] The metal paste according to any of

[11] to

[13] above, wherein the content of the thermosetting resin is 0.5% by mass or more and 10.0% by mass or less when the total solid content of the metal paste is considered to be 100% by mass.

[15] A metal paste according to any of the above [1] to

[14] , further comprising a hardening agent.

[16] The metal paste according to

[15] above, wherein the curing agent includes a phenolic resin-based curing agent.

[17] The metal paste according to the above

[15] or

[16] , wherein the content of the above hardener is 0.1% by mass or more and 5.0% by mass or less based on 100% by mass of the total solid content of the above metal paste.

[18] Viscosity η measured under the conditions of a rotation speed of 5.0 rpm and a temperature of 25°C using a BF-type viscometer and a cone rotor with an angle of 1.565 deg × a radius of 12 mm 5.0 The metal paste according to any one of the above [1] to

[17] , which is 10.0 Pa·s or more and 100.0 Pa·s or less.

[19] Viscosity η measured under the conditions of a rotation speed of 0.5 rpm and a temperature of 25°C using a BF-type viscometer and a cone rotor with an angle of 1.565 deg × a radius of 12 mm 0.5 The metal paste according to the above

[18] , which is 10 Pa·s or more and 1000 Pa·s or less.

[20] The above viscosity η 5.0 To the above viscosity η 0.5 Viscosity ratio η which is the ratio of 0.5 / η 5.0 The metal paste according to the above

[19] , which is 1.0 or more and 10.0 or less.

[21] The metal paste according to any one of the above [1] to

[20] , wherein the die shear strength by the following (Method 1) is 50 N or more and 200 N or less. (Method 1) Apply the above metal paste to the pad portion of a square test copper lead frame with a length of 10 mm × a width of 10 mm × a thickness of 0.15 mm, and place a Au-plated silicon chip with a length of 5.0 mm × a width of 5.0 mm × a thickness of 0.35 mm on the above metal paste so that the center portion of the surface of the above test copper lead frame and the center portion of the surface of the above Au-plated silicon chip overlap in the vertical direction. Then, apply a load of 100 N / ( (5.0 mm × 5.0 mm) from the vertical direction to the surface of the above Au-plated silicon chip to obtain a laminate with an adhesive layer thickness of 20 ± 5 μm. Then, put the above laminate into an electric furnace sufficiently replaced with nitrogen, raise the temperature from 30°C to 200°C at a constant speed over 60 minutes, and then heat-treat at 200°C for 120 minutes to obtain a test piece. For the obtained test specimens, the die shear strength at 260°C is measured using a die shear tester in accordance with JIS Z 3198-7:2003, under the conditions of a measurement speed of 20 mm / min and a measurement temperature of 260°C, by pressing a jig against the side surface of the Au-plated silicon tip at a point 50 μm away perpendicular to the upper surface of the copper lead frame used for the test. [twenty two] Storage modulus E' at 25°C as described below (Method 2) 25 A metal paste as described in any of the above [1] to

[21] , wherein the pressure is between 0.1 MPa and 30.0 MPa. (Method 2) The above metal paste is applied to a mold measuring 4 mm in length, 20 mm in width, and 0.3 mm in thickness. The temperature is raised from 30°C to 200°C at a constant rate over 60 minutes, and then heated at 200°C for 120 minutes to prepare a test specimen. The obtained test specimen is then measured using a dynamic viscoelasticity analyzer in accordance with JIS K 6911:2006, under the conditions of tensile mode, heating rate: 5°C / min, and frequency: 1 Hz, to determine the storage modulus E' at 25°C. 25 Measure. [twenty three] Storage modulus E' at 250°C according to the method (Method 3) below 250 A metal paste as described in any of the above [1] to

[22] , wherein the pressure is between 0.1 MPa and 10.0 MPa. (Method 3) The above metal paste is applied to a mold measuring 4 mm in length, 20 mm in width, and 0.3 mm in thickness. The temperature is raised from 30°C to 200°C at a constant rate over 60 minutes, and then heated at 200°C for 120 minutes to prepare a test specimen. The obtained test specimen is then subjected to a dynamic viscoelasticity analyzer in accordance with JIS K 6911:2006, under the conditions of tensile mode, heating rate: 5°C / min, and frequency: 1 Hz, to determine the storage modulus E' at 250°C. 250 Measure. [twenty four] A metal paste according to any of the above [1] to

[23] , wherein the glass transition temperature according to the following method (4) is 70°C or higher and 300°C or lower. (Method 4) The above metal paste is applied to a mold measuring 4 mm in length, 10 mm in width, and 0.15 mm in thickness. The mold is heated at a constant rate from 30°C to 200°C over 60 minutes, and then heated at 200°C for 120 minutes to prepare a test specimen. Then, using a thermomechanical analyzer, the obtained test specimen is pulled with a load of 10 mN while the temperature is increased from -100°C to 330°C at a heating rate of 5°C / min. The amount of expansion of the test specimen in relation to the temperature is detected as an electrical output using a differential transformer, and a graph showing the amount of expansion of the test specimen in relation to the temperature is created. Then, the glass transition temperature (Tg) is determined from the inflection point of the graph shown above. [twenty five] A metal paste according to any of the above [1] to

[24] , wherein the average coefficient of linear expansion α1 determined by the method described below (Method 5) is 10 ppm / °C or more and 100 ppm / °C or less. (Method 5) The above metal paste is applied to a mold measuring 4 mm in length, 10 mm in width, and 0.15 mm in thickness. The mold is heated at a constant rate from 30°C to 200°C over 60 minutes, and then heated at 200°C for 120 minutes to prepare a test specimen. Then, using a thermomechanical analyzer, the obtained test specimen is pulled with a load of 10 mN while the temperature is increased from -100°C to 330°C at a heating rate of 5°C / min. The amount of expansion of the test specimen in relation to the temperature is detected as an electrical output using a differential transformer, and a graph showing the amount of expansion of the test specimen in relation to the temperature is created. Then, the glass transition temperature (Tg) is determined from the inflection point of the graph shown above. In addition, the average coefficient of linear expansion α1 (ppm / °C) at temperatures below the calculated glass transition temperature (Tg) is measured.

[26] A metal paste according to any of the above [1] to

[25] , wherein the average coefficient of linear expansion α2 determined by the method described below (Method 6) is 40 ppm / °C or more and 150 ppm / °C or less. (Method 6) The above metal paste is applied to a mold measuring 4 mm in length, 10 mm in width, and 0.15 mm in thickness. The mold is heated at a constant rate from 30°C to 200°C over 60 minutes, and then heated at 200°C for 120 minutes to prepare a test specimen. Then, using a thermomechanical analyzer, the obtained test specimen is pulled with a load of 10 mN while the temperature is increased from -100°C to 330°C at a heating rate of 5°C / min. The amount of expansion of the test specimen in relation to the temperature is detected as an electrical output using a differential transformer, and a graph showing the amount of expansion of the test specimen in relation to the temperature is created. Then, the glass transition temperature (Tg) is determined from the inflection point of the graph shown above. In addition, the average coefficient of linear expansion α2 (ppm / °C) at temperatures above the calculated glass transition temperature (Tg) is measured.

[27] A metal paste according to any of the above [1] to

[26] , wherein the curing shrinkage rate by the method described below (Method 7) is 7.0% or less. (Method 7) The above metal paste is applied to a silicon chip 1 measuring 7.0 mm in length and 7.0 mm in width. Then, a silicon chip 2 measuring 3.0 mm in length and 3.0 mm in width is placed on top of the metal paste. Next, a load of 100 N / (3.0 × 3.0 mm) is applied perpendicular to the surface of the silicon chip 2 to obtain a laminate. The thickness of the metal paste at this time is denoted as t0 [μm]. Next, the laminate is placed in an electric furnace that has been sufficiently purged with nitrogen, and the temperature is raised at a constant rate from 30°C to 200°C over 60 minutes, followed by heat treatment at 200°C for 120 minutes to harden the metal paste. The thickness of the metal paste after hardening is denoted as t1 [μm]. Using the measured t0 [μm] and t1 [μm], the curing shrinkage rate is calculated according to JIS K 6941:2019 using the following formula (A). Curing shrinkage rate (%) = ((t0-t1) / t0) × 100 (A)

[28] A metal paste according to any of the above [1] to

[27] , wherein the thermal conductivity according to the method (8) below is 10.0 W / m·K or more and 100.0 W / m·K or less. (Method 8) The above metal paste is applied to a 10 mm × 10 mm × 1.0 mm mold, and the temperature is raised at a constant rate from 30°C to 200°C over 60 minutes, followed by heating at 200°C for 120 minutes to prepare a test specimen. The thermal conductivity of the obtained test specimen is measured using a Xe flash analyzer, under atmospheric conditions and at 25°C, by measuring the thermal diffusivity (α) in the longitudinal direction of the test specimen using the laser flash method (half-time method). Furthermore, the specific heat (Cp) measured by the DSC method and the density (ρ) measured in accordance with JIS K 6911:2006 are used to calculate the thermal conductivity using the following formula. Thermal conductivity [W / m K]=α[mm 2 / s] × Cp[J / kg·K] × ρ[g / cm 3 ]

[29] An electronic device comprising a hardened product formed from any of the metal pastes described in [1] to

[28] above. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a metal paste with an improved balance of performance characteristics, including low elastic modulus, low curing shrinkage, and high thermal conductivity. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described below. In this specification, numerical ranges indicated using "~" represent a range that includes the numbers before and after "~" as the minimum and maximum values, respectively. In numerical ranges described stepwise in this specification, the upper or lower limit of a numerical range in one step can be arbitrarily combined with the upper or lower limit of a numerical range in another step. In numerical ranges described in this specification, the upper or lower limit of that numerical range may be replaced with the values ​​shown in the examples. "A or B" means that either A or B is included, or both are included. Unless otherwise specified, the materials exemplified in this specification can be used individually or in combination of two or more. In this specification, the content of each component in a composition means the total amount of multiple substances present in the composition if there are multiple substances corresponding to each component in the composition, unless otherwise specified. In this specification, "(meth)acrylic" means acrylic, methacrylic, or both acrylic and methacrylic.

[0011] <Metallic Paste> The metal paste of this embodiment is a metal paste containing metal particles, and includes an allyl resin having a polyoxyalkylene skeleton structure and having allyl groups at one or both ends.

[0012] The metal paste of this embodiment has a polyoxyalkylene skeleton structure and includes an allyl resin having allyl groups at one or both ends, thereby improving the balance of low modulus of elasticity, low curing shrinkage, and high thermal conductivity. Because the polyoxyalkylene skeleton structure is relatively soft, in a metal paste using metal particles and an allyl resin having a polyoxyalkylene skeleton structure, the metal particles can easily move to an optimal position for contact with each other. Furthermore, because the allyl resin has allyl groups at one or both ends, the polyoxyalkylene skeleton is more easily introduced into the cross-linked structure between the resins when the metal paste is cured. As a result, it is believed that the metal paste of this embodiment can improve the balance of performance characteristics such as low modulus of elasticity, low curing shrinkage, and high thermal conductivity.

[0013] The components contained in the metal paste of this embodiment will be described in more detail below.

[0014] [Allyl resin] The allyl resin in the metal paste of this embodiment preferably contains a compound represented by the following general formula (1) from the viewpoint of further improving the balance of performance characteristics such as low modulus of elasticity, low curing shrinkage, and high thermal conductivity.

[0015] CH2=CHCH2O-(C m H 2m O) n -R (1)

[0016] In the general formula (1) above, m represents an integer between 1 and 5, n represents an integer between 1 and 10, and R represents a hydrogen atom or an organic group having 1 to 5 carbon atoms.

[0017] Here, an organic group refers to an atomic group obtained by removing one or more hydrogen atoms from an organic compound. For example, a "monovalent organic group" refers to an atomic group obtained by removing one hydrogen atom from any organic compound. The organic group preferably includes one or more selected from the group consisting of alkyl groups such as methyl, ethyl, and n-propyl groups; alkenyl groups such as allyl and vinyl groups; alkynyl groups such as ethynyl groups; alkylidene groups such as methylidene and ethylidene groups; cycloalkyl groups such as cyclopropyl groups; and heterocyclic groups such as epoxy and oxetanyl groups.

[0018] In the above general formula (1), R is preferably an allyl group from the viewpoint of further improving the balance of performance characteristics such as low modulus of elasticity, low hardening shrinkage, and high thermal conductivity. Because R is an allyl group, allyl groups are introduced to both ends of the compound represented by the general formula (1) above, making it easier for the polyoxyalkylene skeleton to be introduced into the cross-linked structure between resins when the metal paste is cured. As a result, it is believed that the metal paste of this embodiment can further improve the balance of low elastic modulus, low curing shrinkage, and high thermal conductivity.

[0019] In the above general formula (1), m is preferably 1 to 4, more preferably 1 to 3, from the viewpoint of further improving the balance of low elastic modulus, low hardening shrinkage, and high thermal conductivity.

[0020] In the above general formula (1), n ​​is preferably 1 to 9, more preferably 1 to 8, even more preferably 2 to 7, and even more preferably 3 to 6, from the viewpoint of further improving the balance of low elastic modulus, low hardening shrinkage, and high thermal conductivity.

[0021] The weight-average molecular weight of the allyl resin, in terms of polystyrene equivalent, is preferably 300 to 2000, more preferably 350 to 1700, even more preferably 400 to 1400, and even more preferably 450 to 1000, from the viewpoint of further improving the balance of performance characteristics such as low modulus of elasticity, low curing shrinkage, and high thermal conductivity.

[0022] In the metal paste of this embodiment, in addition to the compound represented by the general formula (1) above, a known allyl resin may also be used in combination. Known allyl resins can be liquids having two or more allyl groups in their molecule. Specific examples of allyl resins include allyl ester resins obtained by reacting a dicarboxylic acid with an allyl alcohol and a compound containing an allyl group. Here, the dicarboxylic acid includes, for example, one or more selected from the group consisting of oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, phthalic acid, tetrahydrophthalic acid, and hexahydrophthalic acid. Furthermore, the compounds comprising the allyl group include, for example, one or more selected from the group consisting of polyethers, polyesters, polycarbonates, poly(meth)acrylates, polybutadienes, and butadiene acrylonitrile copolymers, all comprising an allyl group.

[0023] The allyl resin content in the metal paste of this embodiment is preferably 0.1% by mass or more and 5.0% by mass or less, more preferably 0.3% by mass or more and 4.5% by mass or less, even more preferably 0.5% by mass or more and 4.0% by mass or less, even more preferably 1.0% by mass or more and 3.5% by mass or less, and even more preferably 1.5% by mass or more and 3.0% by mass or less, when the total solid content of the metal paste is considered to be 100% by mass.

[0024] [Metal particles] The metal paste of this embodiment contains metal particles. The metal particles of this embodiment preferably include one or more selected from the group consisting of silver particles, silver-coated particles, gold particles, platinum particles, palladium particles, copper particles, nickel particles, and alloy particles thereof. More preferably, they include one or more selected from the group consisting of silver particles and silver-coated particles, in order to further improve the balance between high thermal conductivity and ease of handling.

[0025] Commercially available metal particles such as silver particles can be obtained from companies such as Tokuriki Honten Co., Ltd., Fukuda Metal Foil & Powder Industry Co., Ltd., DOWA Electronics Co., Ltd., and DOWA High-Tech Co., Ltd. Commercially available silver-coated particles can be obtained from companies such as Mitsubishi Materials Corporation and Sekisui Chemical Co., Ltd.

[0026] The shape of the metal particles is not particularly limited, but examples include spherical, flake-shaped, and flaky shapes. From the viewpoint of further improving the balance between high thermal conductivity and ease of handling, the metal particles of this embodiment preferably consist of one or more types of spherical and flaky metal particles.

[0027] Average particle size of metal particles (D 50 From the viewpoint of further improving the balance between high thermal conductivity and ease of handling, the particle size is preferably 0.1 μm to 100 μm, more preferably 0.2 μm to 75 μm, even more preferably 0.3 μm to 50 μm, even more preferably 0.4 μm to 30 μm, and even more preferably 0.5 μm to 15 μm. Note that the average particle size of the metal particles (D 50 For example, a commercially available laser particle size distribution analyzer (e.g., Shimadzu Corporation's SALD-7000) can be used to measure the volume-based particle size distribution using the laser diffraction scattering particle size distribution method, and the value at 50% of the cumulative value can be used.

[0028] From the viewpoint of further improving the balance of performance characteristics such as low elastic modulus, low hardening shrinkage, and high thermal conductivity, the content of metal particles in the metal paste of this embodiment is preferably 50% to 99% by mass, more preferably 60% to 98% by mass, even more preferably 70% to 97% by mass, even more preferably 75% to 96% by mass, even more preferably 80% to 95% by mass, even more preferably 85% to 94% by mass, and even more preferably 88% to 93% by mass, when the total solid content of the metal paste is considered to be 100% by mass.

[0029] [Thermosetting resin] The metal paste of this embodiment preferably further contains a thermosetting resin, from the viewpoint of further improving the balance of performance characteristics such as low elastic modulus, low curing shrinkage, and high thermal conductivity. Here, the thermosetting resin in the metal paste of this embodiment excludes the allyl resin mentioned above. That is, if the metal paste of this embodiment contains a thermosetting resin, it includes the allyl resin mentioned above and a thermosetting resin other than the allyl resin mentioned above.

[0030] The thermosetting resin may include known thermosetting resins, but from the viewpoint of further improving the balance of performance characteristics such as low modulus of elasticity, low curing shrinkage, and high thermal conductivity, it preferably includes one or more selected from the group consisting of acrylic resins such as acrylic oligomers and acrylic polymers, and epoxy resins such as epoxy oligomers and epoxy polymers, and more preferably includes epoxy resins.

[0031] The epoxy resin preferably includes one or more selected from the group consisting of aromatic epoxy resins and aliphatic epoxy resins. The aromatic epoxy resin preferably includes one or more selected from the group consisting of: bisphenol-type epoxy resins such as bisphenol A-type epoxy resin and bisphenol F-type epoxy resin; modified bisphenol-type epoxy resins such as modified bisphenol A-type epoxy resin, modified bisphenol F-type epoxy resin and tetramethylbisphenol F-type epoxy resin; crystalline epoxy resins such as biphenyl-type epoxy resin, stilbene-type epoxy resin and hydroquinone-type epoxy resin; novolac-type epoxy resins such as cresol novolac-type epoxy resin, phenol novolac-type epoxy resin and naphthol novolac-type epoxy resin; phenol aralkyl-type epoxy resins such as phenylene skeleton-containing phenol aralkyl-type epoxy resin, biphenylene skeleton-containing phenol aralkyl-type epoxy resin, phenylene skeleton-containing naphthol aralkyl-type epoxy resin and alkoxynaphthalene skeleton-containing phenol aralkyl-type epoxy resin; polyfunctional epoxy resins such as triphenolmethane-type epoxy resin and alkyl-modified triphenolmethane-type epoxy resin; and modified phenol-type epoxy resins such as dicyclopentadiene-modified phenol-type epoxy resin and terpene-modified phenol-type epoxy resin. The aliphatic epoxy resin preferably includes one or more selected from the group consisting of glycidyl ether type epoxy resins such as trimethylolpropane polyglycidyl ether type epoxy resin and polyethylene glycol glycidyl ether type epoxy resin; heterocyclic epoxy resins such as triazine nucleus-containing epoxy resin; and alicyclic epoxy resins such as vinylcyclohexene dioxide, dicyclopentadiene oxide, and alicyclic diepoxy adipade. From the viewpoint of further improving the balance of performance characteristics such as low modulus of elasticity, low curing shrinkage, and high thermal conductivity, the epoxy resin preferably comprises one or more selected from the group consisting of bisphenol-type epoxy resins, crystalline epoxy resins, and novolac-type epoxy resins, more preferably comprises one or more selected from the group consisting of bisphenol-type epoxy resins, phenol novolac-type epoxy resins, cresol novolac-type epoxy resins, and biphenyl-type epoxy resins, and even more preferably comprises a bisphenol-type epoxy resin.

[0032] From the viewpoint of further improving the balance of low elastic modulus, low curing shrinkage, and high thermal conductivity, the content of thermosetting resin in the metal paste of this embodiment is preferably 0.5% to 10.0% by mass, more preferably 1.0% to 9.0% by mass, even more preferably 2.0% to 8.0% by mass, even more preferably 3.0% to 7.0% by mass, and even more preferably 4.0% to 6.0% by mass, when the total solid content of the metal paste is considered as 100% by mass.

[0033] [Hardening agent] The metal paste of this embodiment preferably further contains a curing agent, from the viewpoint of further improving the balance of performance characteristics such as low elastic modulus, low curing shrinkage, and high thermal conductivity.

[0034] The curing agent preferably comprises one or more selected from the group consisting of phenolic resin curing agents, amine curing agents, acid anhydride curing agents, and mercaptan curing agents, and more preferably comprises a phenolic resin curing agent from the viewpoint of further improving the balance of performance characteristics such as low modulus of elasticity, low curing shrinkage, and high thermal conductivity.

[0035] The phenolic resin curing agent preferably includes one or more selected from the group consisting of novolac-type phenolic resins such as phenol novolac resin, cresol novolac resin, naphthol novolac resin, aminotriazine novolac resin, novolac resin, and trisphenylmethane-type phenol novolac resin; modified phenolic resins such as terpene-modified phenolic resin and dicyclopentadiene-modified phenolic resin; aralkyl-type resins such as phenol aralkyl resins having a phenylene skeleton and / or biphenylene skeleton, and naphthol aralkyl resins having a phenylene skeleton and / or biphenylene skeleton; bisphenolic resins having a bisphenol skeleton such as bisphenol A, bisphenol F, and biphenol; and resol-type phenolic resins. From the viewpoint of further improving the balance of performance characteristics such as low modulus of elasticity, low curing shrinkage, and high thermal conductivity, the phenolic resin curing agent preferably contains a bisphenol resin having a bisphenol skeleton, and more preferably contains a biphenol.

[0036] The amine-based curing agent preferably includes a compound having a tertiary amino group. The compounds having a tertiary amino group preferably include one or more selected from the group consisting of tertiary amines such as benzyldimethylamine (BDMA); imidazoles such as 2-methylimidazole and 2-ethyl-4-methylimidazole (EMI24); pyrazoles such as pyrazole, 3,5-dimethylpyrazole, and pyrazoline; triazoles such as triazole, 1,2,3-triazole, 1,2,4-triazole, and 1,2,3-benzotriazole; and imidazolines such as imidazoline, 2-methyl-2-imidazoline, and 2-phenylimidazoline.

[0037] From the viewpoint of further improving the balance of performance characteristics such as low elastic modulus, low curing shrinkage, and high thermal conductivity, the content of the hardening agent in the metal paste of this embodiment is preferably 0.1% to 5.0% by mass, more preferably 0.2% to 4.0% by mass, even more preferably 0.3% to 3.0% by mass, even more preferably 0.4% to 2.0% by mass, and even more preferably 0.5% to 1.2% by mass, when the total solid content of the metal paste is considered as 100% by mass.

[0038] [monomer] The metal paste of this embodiment preferably further contains monomers, from the viewpoint of further improving the balance of performance characteristics such as low elastic modulus, low curing shrinkage, and high thermal conductivity. Here, from the viewpoint of further improving the balance of performance characteristics such as low modulus of elasticity, low curing shrinkage, and high thermal conductivity, the monomer of this embodiment preferably comprises one or more selected from the group consisting of (meth)acrylic monomers and epoxy monomers, and more preferably comprises (meth)acrylic monomers.

[0039] (Meth)acrylic monomers are preferably 2-phenoxyethyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, isoamyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isodecyl (meth)acrylate, n-lauryl (meth)acrylate, n-tridecyl (meth)acrylate, n-stearyl (meth)acrylate, isostearyl (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, butoxydiethylene glycol (meth)acrylate, methoxytriethylene glycol (meth)acrylate, and 2-ethylhexyldiethylene glycol (meth)acrylate, which can further improve the balance of performance characteristics such as low modulus of elasticity, low curing shrinkage, and high thermal conductivity. Methoxypolyethylene glycol (meth)acrylate, methoxydipropylene glycol (meth)acrylate, cyclohexyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, phenoxypolyethylene glycol (meth)acrylate, nonylphenol ethylene oxide modified (meth)acrylate, phenylphenol ethylene oxide modified (meth)acrylate, isobornyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate quaternary compound, glycidyl (meth)acrylate, neopentyl glycol (meth)acrylate benzoate, 1,4-Cyclohexanedimethanol mono(meth)acrylate, 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, 2-hydroxybutyl(meth)acrylate, 2-hydroxy-3-phenoxypropyl(meth)acrylate, 2-(meth)acryloyloxyethyl succinate, 2-(meth)acryloyloxyethyl succinate, 2-(meth)acryloyloxyethyl hexahydrophthalate, 2-(meth)acryloyloxyethyl phthalate, 2-(meth)acryloyloxyethyl phthalate Royloxyethyl-2-hydroxyethyl phthalate, 2-(meth)acryloyloxyethyl acid phosphate, 2-(meth)acryloyloxyethyl acid phosphate, ethylene glycol di(meth)acrylate, polyethylene glycol mono(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol mono(meth)acrylate, polypropylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, propoxy Bisphenol A di(meth)acrylate, 1,6-Hexanediol di(meth)acrylate, Hexane-1,6-diol bis(2-methyl(meth)acrylate), 4,4'-Isopropylidene diphenol di(meth)acrylate, 1,3-Butanediol di(meth)acrylate, 1,6-Bis((meth)acryloyloxy)-2,2,3,3,4,4,5,5-Octafluorohexane, 1,4-Bis((meth)acryloyloxy)butane, 1,6-Bis((meth)acryloyloxy) It comprises one or more selected from the group consisting of hexane, triethylene glycol di(meth)acrylate, polyoxypropylene mono(meth)acrylate, polyethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, N,N'-di(meth)acryloylethylenediamine, N,N'-(1,2-dihydroxyethylene)bis(meth)acrylamide, and 1,4-bis((meth)acryloyl)piperazine. Here, from the viewpoint of further improving the balance of performance such as low modulus of elasticity, low curing shrinkage, and high thermal conductivity, the (meth)acrylic monomer in this embodiment is more preferably 1,It comprises one or more selected from the group consisting of 6-hexanediol di(meth)acrylate, 2-phenoxyethyl (meth)acrylate, polyoxypropylene mono(meth)acrylate, ethylene glycol di(meth)acrylate, polyethylene glycol mono(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol mono(meth)acrylate, and polypropylene glycol di(meth)acrylate, and more preferably one or more selected from the group consisting of ethylene glycol di(meth)acrylate and polypropylene glycol mono(meth)acrylate.

[0040] From the viewpoint of further improving the balance of performance characteristics such as low modulus of elasticity, low curing shrinkage, and high thermal conductivity, the epoxy monomer preferably includes one or more selected from the group consisting of monocyclic epoxy monomers such as 4-tert-butylphenylglycidyl ether, m,p-cresylglycidyl ether, phenylglycidyl ether, and cresylglycidyl ether; bisphenol compounds such as bisphenol A, bisphenol F, biphenol, and bisphenol-F-diglycidyl ether or derivatives thereof; diols having an alicyclic structure such as hydrogenated bisphenol A, hydrogenated bisphenol F, hydrogenated biphenol, cyclohexanediol, cyclohexanedimethanol, cyclohexanediethanol, and 1,4-cyclohexanedimethanol diglycidyl ether or derivatives thereof; bifunctional compounds obtained by epoxidizing aliphatic diols such as butanediol, hexanediol, octanediol, nonanediol, and decanediol or derivatives thereof; and trifunctional compounds having a trihydroxyphenylmethane skeleton or an aminophenol skeleton.

[0041] From the viewpoint of further improving the balance of low elastic modulus, low hardening shrinkage, and high thermal conductivity, the monomer content in the metal paste of this embodiment is preferably 0.1% to 10.0% by mass, more preferably 0.3% to 8.0% by mass, even more preferably 0.5% to 6.0% by mass, even more preferably 1.0% to 4.0% by mass, and even more preferably 1.5% to 2.0% by mass, when the total solid content of the metal paste is considered as 100% by mass.

[0042] [Curing accelerator] The metal paste of this embodiment preferably further contains a curing accelerator, from the viewpoint of improving curability. The curing accelerator preferably comprises one or more compounds selected from the group consisting of phosphorus-containing compounds and nitrogen-containing compounds.

[0043] The phosphorus atom-containing compound preferably includes one or more selected from the group consisting of organophosphines, tetrasubstituted phosphonium compounds, phosphobetaine compounds, adducts of phosphine compounds and quinone compounds, and adducts of phosphonium compounds and silane compounds.

[0044] The nitrogen atom-containing compound preferably includes one or more selected from the group consisting of dicyandiamide or its derivatives, amidines and tertiary amines such as 1,8-diazabicyclo[5.4.0]undecene-7, 2,4-diamino-6-(2'-methylimidazolyl-1-)ethyl-s-triazine, and benzyldimethylamine, or quaternary ammonium salts thereof; and imidazole compounds such as 2-undecylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, and 2-phenyl-1H-imidazole-4,5-dimethanol.

[0045] The curing accelerator of this embodiment preferably contains a nitrogen atom-containing compound, and more preferably contains one or more selected from the group consisting of dicyandiamide or its derivatives and imidazole compounds, from the viewpoint of further improving the balance of performance of the metal paste in terms of curability, low modulus of elasticity, low curing shrinkage, and high thermal conductivity. Here, dicyandiamide or its derivatives also function as adhesion enhancers, as will be described later.

[0046] The content of the curing accelerator in the metal paste of this embodiment is preferably 0.01% to 5.0% by mass, more preferably 0.03% to 4.0% by mass, even more preferably 0.05% to 3.0% by mass, even more preferably 0.06% to 2.0% by mass, even more preferably 0.07% to 1.5% by mass, even more preferably 0.08% to 1.0% by mass, and even more preferably 0.09% to 0.5% by mass, when the total solid content of the metal paste is considered as 100% by mass, in order to further improve the balance of performance of the metal paste, low modulus of elasticity, low curing shrinkage, and high thermal conductivity.

[0047] [Polymerization inhibitor] The metal paste of this embodiment preferably further contains a polymerization inhibitor, from the viewpoint of further improving the balance of performance characteristics such as low modulus of elasticity, low curing shrinkage, and high thermal conductivity. For example, known polymerization inhibitors can be used, but from the viewpoint of further improving the balance of performance characteristics such as low modulus of elasticity, low curing shrinkage, and high thermal conductivity, it is preferable to include one or more selected from the group consisting of HQ (hydroquinone) and MEHQ (hydroquinone monomethyl ether).

[0048] From the viewpoint of further improving the balance of low elastic modulus, low curing shrinkage, and high thermal conductivity, the content of polymerization inhibitor in the metal paste of this embodiment is preferably 0.0001% to 3.0% by mass, more preferably 0.0010% to 2.5% by mass, even more preferably 0.0020% to 2.0% by mass, even more preferably 0.0030% to 1.5% by mass, even more preferably 0.0050% to 1.0% by mass, even more preferably 0.0070% to 0.5% by mass, and even more preferably 0.0090% to 0.1% by mass, when the total solid content of the metal paste is considered as 100% by mass.

[0049] [Coupling agent] The metal paste of this embodiment preferably further includes a coupling agent, from the viewpoint of further improving the balance of performance characteristics such as adhesion between the metal paste and the substrate, low modulus of elasticity, low curing shrinkage, and high thermal conductivity. The coupling agent of this embodiment preferably comprises one or more selected from the group consisting of epoxysilane, sulfidosilane, (meth)acrylsilane, and aminosilane, and more preferably comprises one or more selected from the group consisting of epoxysilane and (meth)acrylsilane, from the viewpoint of further improving the balance of performance such as adhesion between the metal paste and the substrate, low modulus of elasticity, low curing shrinkage, and high thermal conductivity.

[0050] The epoxysilane preferably comprises one or more selected from the group consisting of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidyloxypropylmethyldimethoxysilane, 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropylmethyldiethoxysilane, and 3-glycidyloxypropyltriethoxysilane, and more preferably comprises 3-glycidyloxypropyltrimethoxysilane.

[0051] The sulfidosilane preferably comprises one or more selected from the group consisting of bis(3-(triethoxysilyl)propyl) disulfide, bis(3-(triethoxysilyl)propyl) tetrasulfide, and bis(3-(triethoxysilyl)propyl) polysulfide, and more preferably comprises bis(3-(triethoxysilyl)propyl) tetrasulfide.

[0052] The (meth)acrylosisilane preferably comprises one or more selected from the group consisting of 3-(meth)acryloxypropylmethyldimethoxysilane, 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropylmethyldiethoxysilane, and 3-(meth)acryloxypropyltriethoxysilane, and more preferably comprises 3-(meth)acryloxypropyltrimethoxysilane.

[0053] The aminosilane preferably includes one or more selected from the group consisting of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, and trimethoxy[3-(phenylamino)propyl]silane.

[0054] The coupling agent content in the metal paste of this embodiment is preferably 0.01% to 5.0% by mass, more preferably 0.03% to 4.0% by mass, even more preferably 0.05% to 3.0% by mass, even more preferably 0.10% to 2.0% by mass, and even more preferably 0.15% to 1.0% by mass, when the total solid content of the metal paste is considered as 100% by mass, in order to further improve the balance of performance in terms of adhesion between the metal paste and the substrate, low modulus of elasticity, low curing shrinkage, and high thermal conductivity.

[0055] [Initiating agent] The metal paste of this embodiment may further contain an initiator to improve its curability. The initiator in this embodiment preferably includes a radical polymerization initiator. The radical polymerization initiator preferably includes one or more selected from the group consisting of azo compounds and peroxides.

[0056] The azo compound preferably comprises one or more selected from the group consisting of 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2-cyclopropylpropionitrile), and 2,2'-azobis(2,4-dimethylvaleronitrile).

[0057] The peroxides are preferably ketone peroxides such as methyl ethyl ketone peroxide and cyclohexanone peroxide; peroxyketals such as 1,1-di(tert-butylperoxy)cyclohexane and 2,2-di(4,4-di(t-butylperoxy)cyclohexyl)propane; hydroperoxides such as p-menthane hydroperoxide, diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, and t-butyl hydroperoxide; di(2-t-butylperoxyisopropyl)benzene, dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, t-butyl It contains one or more selected from the group consisting of dialkyl peroxides such as tylcumyl peroxide, di-t-hexyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexine-3, and di-t-butyl peroxide; diacyl peroxides such as dibenzoyl peroxide and di(4-methylbenzoyl) peroxide; peroxydicarbonates such as di-n-propyl peroxydicarbonate and diisopropyl peroxydicarbonate; and peroxyesters such as 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, t-hexyl peroxybenzoate, t-butyl peroxybenzoate, and t-butyl peroxy 2-ethylhexanoate.

[0058] The initiator of this embodiment preferably contains a peroxide, more preferably a dialkyl peroxide, and even more preferably a dicumyl peroxide, from the viewpoint of further improving the performance balance between the reliability of the electronic device and the curability of the metal paste.

[0059] From the viewpoint of further improving the balance of curability, low modulus of elasticity, low curing shrinkage, and high thermal conductivity, the initiator content in the metal paste of this embodiment is preferably 0.01% to 5.0% by mass, more preferably 0.05% to 3.0% by mass, even more preferably 0.10% to 2.0% by mass, even more preferably 0.20% to 1.5% by mass, and even more preferably 0.30% to 1.0% by mass, when the total solid content of the metal paste is considered as 100% by mass.

[0060] [solvent] The metal paste of this embodiment may further contain a solvent to improve fluidity. Solvents include, for example, alcohols such as ethyl alcohol, propyl alcohol, butyl alcohol, pentyl alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol, nonyl alcohol, decyl alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, methyl methoxybutanol, α-terpineol, β-terpineol, hexylene glycol, benzyl alcohol, 2-phenylethyl alcohol, isopalmityl alcohol, isostearyl alcohol, lauryl alcohol, ethylene glycol, propylene glycol, or glycerin; acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, diacetone alcohol (4-hydroxy-4-methyl-2-pentanone), 2-octano Ketones such as isophorone (3,5,5-trimethyl-2-cyclohexen-1-one) or diisobutyl ketone (2,6-dimethyl-4-heptanone); ethyl acetate, butyl acetate, diethyl phthalate, dibutyl phthalate, acetoxyethane, methyl butyrate, methyl hexanoate, methyl octanoate, methyl decanoate, methyl cellosolve acetate, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, 1,2-diacetoxyethane, tributyl phosphate, phosphate Esters such as lycresyl or tripentyl phosphate; ethers such as tetrahydrofuran, dipropyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, propylene glycol dimethyl ether, tripropylene glycol mono-n-butyl ether, ethoxyethyl ether, 1,2-bis(2-diethoxy)ethane or 1,2-bis(2-methoxyethoxy)ethane; ester ethers such as 2-(2-butoxyethoxy)ethane acetate;Examples include ether alcohols such as 2-(2-methoxyethoxy)ethanol and 2-(2-butoxyethoxy)ethanol (butyl carbitol); hydrocarbons such as toluene, xylene, n-paraffin, isoparaffin, dodecylbenzene, turpentine oil, kerosene, or diesel fuel; and volatile nitriles such as acetonitrile or propionitrile.

[0061] From the viewpoint of further improving the balance of performance characteristics such as fluidity, low modulus of elasticity, low curing shrinkage, and high thermal conductivity, the solvent content in the metal paste of this embodiment is preferably 0.1% to 10.0% by mass, more preferably 0.5% to 7.0% by mass, even more preferably 1.0% to 5.0% by mass, even more preferably 1.5% to 4.0% by mass, and even more preferably 2.0% to 3.0% by mass, when the total mass of the metal paste is considered to be 100% by mass.

[0062] [Other ingredients] In addition to the components described above, the metal paste of this embodiment may also contain other components such as adhesion aids like dicyandiamide or its derivatives; antioxidants; dispersants; stress reducers; defoamers; leveling agents; fine silica (thixotropic modifiers); and catalysts.

[0063] From the viewpoint of further improving the balance of performance characteristics such as low modulus of elasticity, low hardening shrinkage, and high thermal conductivity, the total content of other components in the metal paste of this embodiment is preferably 0.0001% to 3.0% by mass, more preferably 0.0010% to 2.5% by mass, even more preferably 0.0020% to 2.0% by mass, even more preferably 0.0030% to 1.5% by mass, even more preferably 0.0050% to 1.0% by mass, even more preferably 0.0070% to 0.5% by mass, and even more preferably 0.0090% to 0.1% by mass, when the total solid content of the metal paste is considered as 100% by mass.

[0064] [Physical properties of metal paste] The viscosity η of the metal paste of this embodiment is measured using a BF-type viscometer and a cone rotor with an angle of 1.565 degrees and a radius of 12 mm, under the conditions of a rotation speed of 5.0 rpm and a temperature of 25°C. 5.0 From the viewpoint of further improving the balance of performance characteristics such as low modulus of elasticity, low curing shrinkage, high thermal conductivity, and workability when using metal paste, the preferred Pa·s is 10.0 Pa·s or more and 100.0 Pa·s or less, more preferably 11.0 Pa·s or more and 90.0 Pa·s or less, even more preferably 12.0 Pa·s or more and 80.0 Pa·s or less, even more preferably 13.0 Pa·s or more and 70.0 Pa·s or less, even more preferably 14.0 Pa·s or more and 60.0 Pa·s or less, and even more preferably 15.0 Pa·s or more and 50.0 Pa·s or less. The viscosity of the metal paste in this embodiment is η 5.0 The results were taken one minute after the rotation speed of the BF-type viscometer was set to 5 rpm.

[0065] The viscosity η of the metal paste of this embodiment is measured using a BF-type viscometer and a cone rotor with an angle of 1.565 degrees and a radius of 12 mm, under the conditions of a rotation speed of 0.5 rpm and a temperature of 25°C. 0.5 From the viewpoint of further improving the balance of performance characteristics such as low modulus of elasticity, low curing shrinkage, high thermal conductivity, and workability when using metal paste, the preferred Pa·s is 10 Pa·s to 1000 Pa·s, more preferably 30 Pa·s to 900 Pa·s, even more preferably 50 Pa·s to 800 Pa·s, even more preferably 75 Pa·s to 700 Pa·s, even more preferably 100 Pa·s to 600 Pa·s, even more preferably 120 Pa·s to 500 Pa·s, even more preferably 130 Pa·s to 400 Pa·s, even more preferably 140 Pa·s to 300 Pa·s, and even more preferably 150 Pa·s to 200 Pa·s. The viscosity of the metal paste in this embodiment is η 0.5 The results were obtained 6 minutes after the rotation speed of the BF-type viscometer was set to 0.5 rpm.

[0066] The viscosity η of the metal paste of this embodiment 5.0 The viscosity η0.5 The viscosity ratio η is the ratio of 0.5 / η 5.0 From the viewpoint of further improving the balance of performance characteristics such as low modulus of elasticity, low curing shrinkage, high thermal conductivity, and workability when using metal paste, the modulus is preferably 1.0 to 10.0, more preferably 2.0 to 8.0, even more preferably 3.0 to 6.0, and even more preferably 4.0 to 5.0.

[0067] Examples of BF-type viscometers used for measuring the viscosity of the metal paste in this embodiment include the Brookfield DV3T, for example.

[0068] The die shear strength of the metal paste of this embodiment, obtained by the following method (Method 1), is preferably 50N to 200N, more preferably 60N to 175N, even more preferably 70N to 150N, and even more preferably 80N to 100N, from the viewpoint of further improving the balance of low modulus of elasticity, low curing shrinkage, and high thermal conductivity.

[0069] (Method 1) The above metal paste is applied to the pad portion of a square-shaped test copper lead frame measuring 10 mm in length, 10 mm in width, and 0.15 mm in thickness. An Au-plated silicon chip measuring 5.0 mm in length, 5.0 mm in width, and 0.35 mm in thickness is placed on the metal paste so that the center of the surface of the test copper lead frame and the center of the surface of the Au-plated silicon chip overlap vertically. A load of 100 N / (5.0 mm × 5.0 mm) is then applied perpendicularly to the surface of the Au-plated silicon chip to obtain a laminate with an adhesive layer thickness of 20 ± 5 μm. The laminate is then placed in an electric furnace that has been sufficiently purged with nitrogen, and the temperature is raised at a constant rate from 30 °C to 200 °C over 60 minutes, followed by heat treatment at 200 °C for 120 minutes to obtain a test specimen. For the obtained test specimens, the die shear strength at 260°C is measured using a die shear tester in accordance with JIS Z 3198-7:2003, under the conditions of a measurement speed of 20 mm / min and a measurement temperature of 260°C, by pressing a jig against the side surface of the Au-plated silicon tip at a point 50 μm away perpendicular to the upper surface of the copper lead frame used for the test.

[0070] Examples of die shear testers used to measure the die shear strength of the metal paste in this embodiment include the DAGE-4000 Plus model manufactured by Nordson Advanced Technologies.

[0071] The storage modulus E' of the metal paste of this embodiment at 25°C, as determined by the following method (Method 2). 25 From the viewpoint of further improving the balance of performance characteristics such as low modulus of elasticity, low hardening shrinkage, and high thermal conductivity, the pressure is preferably 0.1 MPa to 30.0 MPa, more preferably 0.5 MPa to 25.0 MPa, even more preferably 1.0 MPa to 20.0 MPa, even more preferably 2.0 MPa to 17.0 MPa, even more preferably 3.0 MPa to 14.0 MPa, even more preferably 4.0 MPa to 11.0 MPa, and even more preferably 5.0 MPa to 9.0 MPa.

[0072] (Method 2) The above metal paste is applied to a mold measuring 4 mm in length, 20 mm in width, and 0.3 mm in thickness. The temperature is raised from 30°C to 200°C at a constant rate over 60 minutes, and then heated at 200°C for 120 minutes to prepare a test specimen. The obtained test specimen is then measured using a dynamic viscoelasticity analyzer in accordance with JIS K 6911:2006, under the conditions of tensile mode, heating rate: 5°C / min, and frequency: 1 Hz, to determine the storage modulus E' at 25°C. 25 Measure.

[0073] The storage modulus E' of the metal paste of this embodiment at 250°C, determined by the following method (3) 250From the viewpoint of further improving the balance of performance characteristics such as low modulus of elasticity, low hardening shrinkage, and high thermal conductivity, the pressure is preferably 0.1 MPa to 10.0 MPa, more preferably 0.5 MPa to 7.0 MPa, even more preferably 1.0 MPa to 5.0 MPa, even more preferably 1.5 MPa to 4.0 MPa, and even more preferably 2.0 MPa to 3.0 MPa.

[0074] (Method 3) The above metal paste is applied to a mold measuring 4 mm in length, 20 mm in width, and 0.3 mm in thickness. The temperature is raised from 30°C to 200°C at a constant rate over 60 minutes, and then heated at 200°C for 120 minutes to prepare a test specimen. The obtained test specimen is then subjected to a dynamic viscoelasticity analyzer in accordance with JIS K 6911:2006, under the conditions of tensile mode, heating rate: 5°C / min, and frequency: 1 Hz, to determine the storage modulus E' at 250°C. 250 Measure.

[0075] Examples of dynamic viscoelasticity measuring instruments used to measure the storage modulus of the metal paste in this embodiment include the DMS6100 manufactured by SII Nanotechnology. Generally, the storage modulus E' at 25°C is also used. 25 Storage modulus E' at 15.0 MPa or less and 250°C 250 A pressure of 5.0 MPa or less is within the practical range.

[0076] The glass transition temperature of the metal paste of this embodiment, as determined by the following method (Method 4), is preferably 70°C to 300°C, more preferably 75°C to 280°C, even more preferably 80°C to 260°C, even more preferably 85°C to 240°C, even more preferably 90°C to 220°C, even more preferably 95°C to 200°C, even more preferably 100°C to 180°C, even more preferably 105°C to 170°C, and even more preferably 110°C to 160°C, from the viewpoint of further improving the balance of low elastic modulus, low hardening shrinkage, and high thermal conductivity.

[0077] (Method 4) The above metal paste is applied to a mold measuring 4 mm in length, 10 mm in width, and 0.15 mm in thickness. The mold is heated at a constant rate from 30°C to 200°C over 60 minutes, and then heated at 200°C for 120 minutes to prepare a test specimen. Then, using a thermomechanical analyzer, the obtained test specimen is pulled with a load of 10 mN while the temperature is increased from -100°C to 330°C at a heating rate of 5°C / min. The amount of expansion of the test specimen in relation to the temperature is detected as an electrical output using a differential transformer, and a graph showing the amount of expansion of the test specimen in relation to the temperature is created. Then, the glass transition temperature (Tg) is determined from the inflection point of the graph shown above.

[0078] The average linear expansion coefficient α1 of the metal paste of this embodiment, as determined by the following method (5), is preferably 10 ppm / °C to 100 ppm / °C, more preferably 15 ppm / °C to 80 ppm / °C, even more preferably 20 ppm / °C to 70 ppm / °C, even more preferably 25 ppm / °C to 60 ppm / °C, even more preferably 30 ppm / °C to 50 ppm / °C, and even more preferably 35 ppm / °C to 45 ppm / °C, from the viewpoint of further improving the balance of low elastic modulus, low hardening shrinkage, and high thermal conductivity.

[0079] (Method 5) The above metal paste is applied to a mold measuring 4 mm in length, 10 mm in width, and 0.15 mm in thickness. The mold is heated at a constant rate from 30°C to 200°C over 60 minutes, and then heated at 200°C for 120 minutes to prepare a test specimen. Then, using a thermomechanical analyzer, the obtained test specimen is pulled with a load of 10 mN while the temperature is increased from -100°C to 330°C at a heating rate of 5°C / min. The amount of expansion of the test specimen in relation to the temperature is detected as an electrical output using a differential transformer, and a graph showing the amount of expansion of the test specimen in relation to the temperature is created. Then, the glass transition temperature (Tg) is determined from the inflection point of the graph shown above. In addition, the average coefficient of linear expansion α1 (ppm / °C) at temperatures below the calculated glass transition temperature (Tg) is measured.

[0080] The average linear expansion coefficient α2 of the metal paste of this embodiment, as determined by the following method (Method 6), is preferably 40 ppm / °C to 150 ppm / °C, more preferably 45 ppm / °C to 130 ppm / °C, even more preferably 50 ppm / °C to 110 ppm / °C, even more preferably 55 ppm / °C to 100 ppm / °C, even more preferably 60 ppm / °C to 90 ppm / °C, and even more preferably 65 ppm / °C to 80 ppm / °C, from the viewpoint of further improving the balance of low modulus of elasticity, low hardening shrinkage, and high thermal conductivity.

[0081] (Method 6) The above metal paste is applied to a mold measuring 4 mm in length, 10 mm in width, and 0.15 mm in thickness. The mold is heated at a constant rate from 30°C to 200°C over 60 minutes, and then heated at 200°C for 120 minutes to prepare a test specimen. Then, using a thermomechanical analyzer, the obtained test specimen is pulled with a load of 10 mN while the temperature is increased from -100°C to 330°C at a heating rate of 5°C / min. The amount of expansion of the test specimen in relation to the temperature is detected as an electrical output using a differential transformer, and a graph showing the amount of expansion of the test specimen in relation to the temperature is created. Then, the glass transition temperature (Tg) is determined from the inflection point of the graph shown above. In addition, the average coefficient of linear expansion α2 (ppm / °C) at temperatures above the calculated glass transition temperature (Tg) is measured.

[0082] Examples of thermomechanical analyzers used to measure the glass transition temperature (Tg) and mean linear expansion coefficient of the metal paste in this embodiment include the TMA / SS6100, manufactured by Seiko Instruments Corporation.

[0083] The curing shrinkage rate of the metal paste of this embodiment, as determined by the following method (Method 7), is preferably 7.0% or less, more preferably 6.5% or less, even more preferably 6.0% or less, even more preferably 5.5% or less, and even more preferably 5.0% or less, from the viewpoint of further improving the balance of low elastic modulus, low curing shrinkage, and high thermal conductivity. Furthermore, the lower limit of the curing shrinkage rate of the metal paste in this embodiment is not particularly limited, but for example, it is 0.0% or more.

[0084] (Method 7) The above metal paste is applied to a silicon chip 1 measuring 7.0 mm in length and 7.0 mm in width. Then, a silicon chip 2 measuring 3.0 mm in length and 3.0 mm in width is placed on top of the metal paste. Next, a load of 100 N / (3.0 × 3.0 mm) is applied perpendicular to the surface of the silicon chip 2 to obtain a laminate. The thickness of the metal paste at this time is denoted as t0 [μm]. Next, the laminate is placed in an electric furnace that has been sufficiently purged with nitrogen, and the temperature is raised at a constant rate from 30°C to 200°C over 60 minutes, followed by heat treatment at 200°C for 120 minutes to harden the metal paste. The thickness of the metal paste after hardening is denoted as t1 [μm]. Using the measured t0 [μm] and t1 [μm], the curing shrinkage rate is calculated according to JIS K 6941:2019 using the following formula (A). Curing shrinkage rate (%) = ((t0-t1) / t0) × 100 (A)

[0085] The thermal conductivity of the metal paste of this embodiment, obtained by the following method (8), is preferably 10.0 W / m·K or more and 100.0 W / m·K or less, more preferably 12.0 W / m·K or more and 85.0 W / m·K or less, even more preferably 14.0 W / m·K or more and 70.0 W / m·K or less, even more preferably 16.0 W / m·K or more and 55.0 W / m·K or less, even more preferably 18.0 W / m·K or more and 45.0 W / m·K or less, and even more preferably 20.0 W / m·K or more and 35.0 W / m·K or less.

[0086] (Method 8) The above metal paste is applied to a 10 mm × 10 mm × 1.0 mm mold, and the temperature is raised at a constant rate from 30°C to 200°C over 60 minutes, followed by heating at 200°C for 120 minutes to prepare a test specimen. The thermal conductivity of the obtained test specimen is measured using a Xe flash analyzer, under atmospheric conditions and at 25°C, by measuring the thermal diffusivity (α) in the longitudinal direction of the test specimen using the laser flash method (half-time method). Furthermore, the specific heat (Cp) measured by the DSC method and the density (ρ) measured in accordance with JIS K 6911:2006 are used to calculate the thermal conductivity using the following formula. Thermal conductivity [W / m K]=α[mm 2 / s] × Cp[J / kg·K] × ρ[g / cm 3 ]

[0087] Examples of Xe flash analyzers used to measure the thermal conductivity of the metal paste in this embodiment include the TD-1RTV, manufactured by ULVAC.

[0088] [Method for manufacturing metal paste] The method for preparing the metal paste in this embodiment is not particularly limited, but for example, after pre-mixing the above-mentioned components, a paste-like composition can be obtained by kneading using a three-roller system and then vacuum degassing. In this case, the long-term workability of the metal paste can be improved by appropriately adjusting the preparation conditions, such as performing the pre-mixing under reduced pressure.

[0089] [Application] The metal paste of this embodiment is suitably used, for example, in electronic devices such as semiconductor packages. Here, specific types of semiconductor packages include MAP (Mold Array Package), QFP (Quad Flat Package), SOP (Small Outline Package), CSP (Chip Size Package), QFN (Quad Flat Non-leaded Package), SON (Small Outline Non-leaded Package), BGA (Ball Grid Array), LF-BGA (Lead Flame BGA), FCBGA (Flip Chip BGA), MAPBGA (Molded Array Process BGA), eWLB (Embedded Wafer-Level BGA), Fan-In type eWLB, and Fan-Out type eWLB.

[0090] <Electronic equipment> The electronic device of this embodiment preferably includes a cured product formed from the metal paste of this embodiment. The cured product described above is preferably included in the adhesive layer that bonds the substrate and the electronic component in the electronic device of this embodiment.

[0091] Here, the lower limit of the thickness of the adhesive layer is preferably 5 μm or more, and more preferably 10 μm or more, from the viewpoint of enabling the metal paste of this embodiment to exhibit suitable adhesion and improve the operational reliability of the electronic device. Furthermore, the upper limit of the adhesive layer thickness is preferably 50 μm or less, and more preferably 30 μm or less, from the viewpoint of suppressing warping of electronic devices due to moisture absorption, etc. Furthermore, from the viewpoint of further improving the balance between the operational reliability of the electronic device and the performance of suppressing warping of the electronic device, the thickness of the adhesive layer is preferably 5 μm to 50 μm, and more preferably 10 μm to 30 μm.

[0092] The substrate is preferably an organic substrate, a ceramic substrate, a semiconductor wafer, a lead frame, a BGA substrate, a mounting substrate, a heat spreader, and a heat sink, and more preferably a lead frame. When the substrate is a lead frame, electronic components are mounted on the substrate via an adhesive layer. Furthermore, the electronic components are electrically connected to the substrate, for example, via bonding wires. The lead frame substrate is composed of, for example, a 42 alloy or a Cu frame.

[0093] The organic substrate preferably comprises one or more selected from the group consisting of epoxy resin, cyanate resin, and maleimide resin. Furthermore, the surface of the substrate may be coated with a metal such as silver or gold. This can improve the adhesion between the adhesive layer and the substrate.

[0094] The electronic components may be known electronic components, but preferably include one or more selected from the group consisting of ICs, LSIs, LEDs, and power semiconductor devices (power semiconductors).

[0095] [Manufacturing method for electronic devices] An example of a method for manufacturing the electronic device of this embodiment will be described. First, the metal paste of this embodiment is applied to the substrate, and then the electronic components are placed on top of it. That is, the substrate, metal paste, and electronic components are layered in this order. The method for applying the metal paste of this embodiment is not limited, but specifically, dispensing, printing, inkjet, etc., can be used. Next, the metal paste of this embodiment is heat-treated to harden it. This heat treatment causes the metal particles in the paste to aggregate, and a heat-conducting layer is formed in the adhesive layer, where the interfaces between multiple metal particles disappear. The heat treatment conditions can be set, for example, by raising the temperature from 10°C to 30°C to 100°C to 300°C over 10 minutes to 2 hours, and then continuing the heat treatment at the increased temperature for 10 minutes to 6 hours. This bonds the substrate and the electronic component via the adhesive layer. Next, the electronic component and the substrate are electrically connected using bonding wires. Finally, the electronic component is sealed with a sealing resin. This allows for the manufacture of an electronic device.

[0096] The embodiments of the present invention have been described above, but these are merely examples, and various other configurations can also be adopted. Furthermore, the present invention is not limited to the embodiments described above, and any modifications, improvements, etc., that can achieve the objectives of the present invention are included in the present invention. [Examples]

[0097] The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto.

[0098] <Manufacturing methods for examples and comparative examples> For each example and comparative example, a metal paste was prepared and evaluated using the blending amounts (parts by mass) listed in Table 1. Specifically, first, the components in the blending amounts listed in "Varnish Composition" in Table 1 were kneaded at room temperature in a three-roll mill, and then degassed under vacuum to produce a varnish-like mixture. Next, the obtained varnish-like mixture was used in the blending amounts (parts by mass) listed in "Paste Composition" in Table 1, and the varnish-like mixture, metal particles, and solvent were mixed and kneaded at room temperature in a three-roll mill to obtain a paste-like composition (metal paste). The components used in each example and comparative example are as follows:

[0099] (thermosetting resin) Thermosetting resin 1: Bisphenol-type epoxy resin (Product name: RE-303S, manufactured by Nippon Kayaku Co., Ltd.)

[0100] (Allyl resin) Allyl resin 1: Allyl resin that does not have a polyoxyalkylene skeleton structure (compound not represented by general formula (1)) Allyl resin 2: Polyethylene glycol-diallyl ether (Product name: Uniox® PKA-7201, manufactured by NOF Corporation, weight-average molecular weight: 500) Allyl resin 3: Polyethylene glycol-diallyl ether (Product name: Uniox (registered trademark) PKA-6206, manufactured by NOF Corporation, weight-average molecular weight: 800)

[0101] (Acrylic monomer) Acrylic monomer 1: Polypropylene glycol monomethacrylate (Product name: Bremmer PP-800, manufactured by NOF Corporation, weight-average molecular weight: 840) Acrylic monomer 2: Ethylene glycol dimethacrylate (Product name: Light Ester EG, manufactured by Kyoeisha Chemical Co., Ltd.)

[0102] (Hardening agent) Hardener 1: 4,4'-biphenol

[0103] (Curing accelerator) Curing accelerator 1: 2-phenyl-1H-imidazole-4,5-dimethanol (product name: 2PHZ-PW, manufactured by Shikoku Chemicals Co., Ltd.)

[0104] (Adhesion enhancer) Adhesion aid 1: Dicyandiamide derivative (Product name: EH-3636AS, manufactured by ADEKA Corporation)

[0105] (Polymerization inhibitor) Polymerization inhibitor 1: Hydroquinone monomethyl ether

[0106] (Coupling agent) Coupling agent 1: 3-methacryloxypropyltrimethoxysilane (product name: KBM-503P, manufactured by Shin-Etsu Chemical Co., Ltd.) Coupling agent 2: 3-Glycidyloxypropyltrimethoxysilane (Product name: KBM-403E, manufactured by Shin-Etsu Chemical Co., Ltd.)

[0107] (Initiator) Initiator 1: Dicumyl peroxide (Product name: Percadox BC, manufactured by Nuurion Co., Ltd.)

[0108] (metal particles) Metal particles 1: Silver particles (Product name: HKD-13A, manufactured by Fukuda Metal Foil Powder Industry Co., Ltd., HKD-13A, flake type, D 50 :6.0μm) Metal particles 2: Silver particles (product name: AG-DSB-114, manufactured by DOWA Electronics, spherical, D 50 :0.7μm) Metal particles 3: Silver-plated silicone resin particles (manufactured by Mitsubishi Materials Corporation, heat-resistant, surface-treated, 10μm, spherical shape)

[0109] (solvent) Solvent 1: Tripropylene glycol mono-n-butyl ether (product name: BFTG, manufactured by Nippon Emulsifier Co., Ltd.)

[0110] Average particle diameter D of the above metal particles 50 The values ​​used were those obtained when the cumulative value of the volume-based particle size distribution was 50%, using the laser diffraction scattering particle size distribution measurement method with a laser diffraction particle size distribution analyzer (SALD-7000, manufactured by Shimadzu Corporation).

[0111] <Evaluation of physical properties> The physical properties of the metal pastes obtained in each example and comparative example were evaluated using the following method. The measurement results are shown in Table 1.

[0112] (viscosity) For each example and comparative example of metal paste, the viscosity η was measured using a BF-type viscometer (Brookfield, product name: DV3T) and a cone rotor with an angle of 1.565 degrees and a radius of 12 mm, under conditions of a rotation speed of 5.0 rpm and a temperature of 25°C. 5.0 and viscosity η measured under conditions of rotational speed 0.5 rpm and temperature 25°C 0.5 The viscosity η at a rotational speed of 5.0 rpm was measured. 5.0 Next, viscosity η at a rotational speed of 0.5 rpm 0.5 The measurements were performed in the following order. Furthermore, the viscosity η was also measured. 5.0 The value of was obtained 1 minute after the rotation speed of the BF type viscometer was set to 5.0 rpm. Furthermore, the viscosity η was also used. 0.5 The value used was the one obtained 6 minutes after the rotation speed of the BF-type viscometer was set to 0.5 rpm. Also, the measured viscosity η 5.0 and viscosity η 0.5 Therefore, the viscosity η 5.0 The viscosity η0.5 Viscosity ratio η 0.5 / η 5.0 The result was calculated.

[0113] (Die share strength) A metal paste for each example and comparative example was applied to the pad portion of a square-shaped test copper lead frame measuring 10 mm in length, 10 mm in width, and 0.15 mm in thickness. An Au-plated silicon chip measuring 5.0 mm in length, 5.0 mm in width, and 0.35 mm in thickness was placed on the metal paste so that the center portion of the surface of the test copper lead frame and the center portion of the surface of the Au-plated silicon chip overlapped vertically. A load of 100 N / (5.0 mm × 5.0 mm) was then applied perpendicularly to the surface of the Au-plated silicon chip to obtain a laminate with an adhesive layer thickness of 20 ± 5 μm. The laminate was then placed in an electric furnace that had been sufficiently purged with nitrogen, and the temperature was raised at a constant rate from 30 °C to 200 °C over 60 minutes, followed by heat treatment at 200 °C for 120 minutes to obtain a test specimen. For the obtained test specimens, the die shear strength at 260°C was measured using a die shear tester (Nordson Advanced Technologies, product name: DAGE-4000 Plus) in accordance with JIS Z 3198-7:2003, under conditions of a measurement speed of 20 mm / min and a measurement temperature of 260°C, by pressing a jig against the side surface of the Au-plated silicon tip at a point 50 μm away perpendicular to the upper surface of the above-mentioned copper lead frame.

[0114] (Mean coefficient of linear thermal expansion, glass transition temperature (Tg)) Metal pastes from each example and comparative example were applied to molds measuring 4 mm (length) x 10 mm (width) x 0.15 mm (thickness). Test specimens were prepared by heating them at a constant rate from 30°C to 200°C over 60 minutes, followed by heating at 200°C for 120 minutes. Then, using a thermomechanical analyzer (Seiko Instruments, product name: TMA / SS6100), the obtained test specimens were subjected to a 10 mN load while their temperature was increased from -100°C to 330°C at a heating rate of 5°C / min. The amount of expansion of the test specimens in relation to temperature was detected as an electrical output using a differential transformer, and a graph showing the amount of expansion of the test specimens in relation to temperature was created. The glass transition temperature (Tg) was then determined from the inflection point of the graph shown above. Furthermore, the average linear expansion coefficient α1 (ppm / °C) at temperatures below the calculated glass transition temperature (Tg) and the average linear expansion coefficient α2 (ppm / °C) at temperatures above the glass transition temperature (Tg) were measured.

[0115] (Storage modulus) Metal pastes from each example and comparative example were applied to a mold measuring 4 mm (length) x 20 mm (width) x 0.3 mm (thickness). Test specimens were prepared by heating from 30°C to 200°C at a constant rate over 60 minutes, followed by heating at 200°C for 120 minutes. The obtained test specimens were then measured using a dynamic viscoelasticity analyzer (SII Nanotechnology, product name: DMS6100) in accordance with JIS K 6911:2006, under the conditions of tensile mode, heating rate: 5°C / min, and frequency: 1 Hz, to determine the storage modulus E' at 25°C. 25 and the storage modulus E' at 250°C 250 We measured it. Generally speaking, the storage modulus E' at 25°C is... 25 Storage modulus E' at 15.0 MPa or less and 250°C 250 A pressure of 5.0 MPa or less is within the practical range.

[0116] (Hardening shrinkage rate) A silicon chip 1 measuring 7.0 mm in length and 7.0 mm in width was coated with the metal paste of each example and comparative example. Then, a silicon chip 2 measuring 3.0 mm in length and 3.0 mm in width was placed on top of the metal paste. Next, a load of 100 N / (3.0 × 3.0 mm) was applied perpendicular to the surface of the silicon chip 2 to obtain a laminate. The thickness of the metal paste at this time was defined as t0 [μm]. Next, the laminate was placed in an electric furnace that had been sufficiently purged with nitrogen, and the temperature was raised at a constant rate from 30°C to 200°C over 60 minutes, followed by heat treatment at 200°C for 120 minutes to harden the metal paste. The thickness of the metal paste after hardening was defined as t1 [μm]. Using the measured t0 [μm] and t1 [μm], the curing shrinkage rate was calculated according to JIS K 6941:2019 using the following formula (A). Curing shrinkage rate (%) = ((t0-t1) / t0) × 100 (A)

[0117] (Thermal conductivity) Metal pastes from each example and comparative example were applied to a 10 mm × 10 mm × 1.0 mm mold, and test specimens were prepared by heating from 30°C to 200°C at a constant rate over 60 minutes, followed by heating at 200°C for 120 minutes. The thermal conductivity of the obtained test specimens was measured using a Xe flash analyzer (ULVAC, product name: TD-1RTV) under atmospheric conditions and at 25°C, by measuring the thermal diffusivity (α) in the longitudinal direction of the test specimen using the laser flash method (half-time method). Furthermore, the specific heat (Cp) measured by the DSC method and the density (ρ) measured in accordance with JIS K 6911:2006 were used to calculate the thermal conductivity using the following formula. Thermal conductivity [W / m K]=α[mm 2 / s] × Cp[J / kg·K] × ρ[g / cm 3 ]

[0118] [Table 1]

[0119] In each embodiment, which included an allyl resin having a polyoxyalkylene skeleton structure and allyl groups at one or both ends, the balance of performance characteristics such as low modulus of elasticity, low curing shrinkage, and high thermal conductivity was improved.

Claims

1. A metal paste containing metal particles, A metal paste comprising an allyl resin having a polyoxyalkylene skeleton structure and having allyl groups at one or both ends.

2. The metal paste according to claim 1, wherein the allyl resin comprises a compound represented by the following general formula (1). CH ２ =CHCH ２ O-(C ｍ H ２ｍ O) ｎ -R (1) (In the general formula (1) above, m represents an integer between 1 and 5, n represents an integer between 1 and 10, and R represents a hydrogen atom or an organic group having 1 to 5 carbon atoms.)

3. The metal paste according to claim 2, wherein R in the general formula (1) is an allyl group.

4. The metal paste according to claim 2, wherein m in the general formula (1) is 1 or more and 3 or less.

5. The metal paste according to claim 2, wherein n in the general formula (1) is 3 or more and 6 or less.

6. The metal paste according to any one of claims 1 to 5, wherein the weight-average molecular weight of the allyl resin, on a polystyrene basis, is 300 or more and 2000 or less.

7. The metal paste according to any one of claims 1 to 5, wherein the allyl resin content is 0.1% by mass or more and 5.0% by mass or less when the total solid content of the metal paste is considered to be 100% by mass.

8. The metal paste according to any one of claims 1 to 5, wherein the metal particles include one or more selected from the group consisting of silver particles, silver-coated particles, gold particles, platinum particles, palladium particles, copper particles, nickel particles, and alloy particles thereof.

9. The average particle diameter (D) in the volume-based particle size distribution obtained by the laser diffraction scattering particle size distribution measurement method for the aforementioned metal particles. ５０ A metal paste according to any one of claims 1 to 5, wherein the particle size is 0.1 μm or more and 100 μm or less.

10. The metal paste according to any one of claims 1 to 5, wherein the content of the metal particles is 50% by mass or more and 99% by mass or less when the total solid content of the metal paste is considered to be 100% by mass.

11. The metal paste according to any one of claims 1 to 5, further comprising a thermosetting resin (excluding the allyl resin).

12. The metal paste according to claim 11, wherein the thermosetting resin includes an epoxy resin.

13. The metal paste according to claim 12, wherein the epoxy resin comprises one or more selected from the group consisting of bisphenol-type epoxy resin, phenol novolac-type epoxy resin, cresol novolac-type epoxy resin, and biphenyl-type epoxy resin.

14. The metal paste according to claim 11, wherein the content of the thermosetting resin is 0.5% by mass or more and 10.0% by mass or less, when the total solid content of the metal paste is considered to be 100% by mass.

15. The metal paste according to any one of claims 1 to 5, further comprising a hardening agent.

16. The metal paste according to claim 15, wherein the curing agent comprises a phenolic resin-based curing agent.

17. The metal paste according to claim 15, wherein the content of the hardening agent is 0.1% by mass or more and 5.0% by mass or less, when the total solid content of the metal paste is considered to be 100% by mass.

18. Viscosity η is measured using a BF-type viscometer and a cone rotor with an angle of 1.565 degrees and a radius of 12 mm, under conditions of a rotation speed of 5.0 rpm and a temperature of 25°C. ５．０ A metal paste according to any one of claims 1 to 5, wherein the pressure is 10.0 Pa·s or more and 100.0 Pa·s or less.

19. Viscosity η is measured using a BF-type viscometer and a cone rotor with an angle of 1.565 degrees and a radius of 12 mm, under conditions of a rotation speed of 0.5 rpm and a temperature of 25°C. ０．５ The metal paste according to claim 18, wherein the pressure is 10 Pa·s or more and 1000 Pa·s or less.

20. The viscosity η ５．０ The viscosity η ０．５ The viscosity ratio η ０．５ / η ５．０ is 1.0 or more and 10.0 or less, and the metal paste according to claim 19.

21. A metal paste according to any one of claims 1 to 5, wherein the die shear strength by the method described below (Method 1) is 50 N or more and 200 N or less. (Method 1) The metal paste is applied to the pad portion of a square test copper lead frame measuring 10 mm in length, 10 mm in width, and 0.15 mm in thickness. An Au-plated silicon chip measuring 5.0 mm in length, 5.0 mm in width, and 0.35 mm in thickness is placed on the metal paste so that the center portion of the surface of the test copper lead frame and the center portion of the surface of the Au-plated silicon chip overlap perpendicularly. Then, a force of 100 N / ( from a perpendicular direction is applied to the surface of the Au-plated silicon chip. A laminate with an adhesive layer thickness of 20 ± 5 μm is obtained by applying a load of 5.0 mm × 5.0 mm. Next, the laminate is placed in an electric furnace that has been sufficiently purged with nitrogen, and the temperature is raised at a constant rate from 30°C to 200°C over 60 minutes, followed by heat treatment at 200°C for 120 minutes to obtain a test specimen. For the obtained test specimens, the die shear strength at 260°C is measured using a die shear tester in accordance with JIS Z 3198-7:2003, under the conditions of a measurement speed of 20 mm / min and a measurement temperature of 260°C, by pressing a jig against the side surface of the Au-plated silicon tip at a point 50 μm away perpendicular to the upper surface of the test copper lead frame.

22. Storage modulus E' at 25°C according to the method described below (Method 2) ２５ A metal paste according to any one of claims 1 to 5, wherein the pressure is 0.1 MPa or more and 30.0 MPa or less. (Method 2) The aforementioned metal paste is applied to a mold measuring 4 mm in length, 20 mm in width, and 0.3 mm in thickness. The mold is heated at a constant rate from 30°C to 200°C over 60 minutes, and then heated at 200°C for 120 minutes to prepare a test specimen. The obtained test specimen is then subjected to a dynamic viscoelasticity analyzer in accordance with JIS K 6911:2006, under the conditions of tensile mode, heating rate: 5°C / min, and frequency: 1 Hz, to determine the storage modulus E' at 25°C. ２５ Measure.

23. Storage modulus E' at 250°C according to the method (Method 3) below ２５０ A metal paste according to any one of claims 1 to 5, wherein the pressure is 0.1 MPa or more and 10.0 MPa or less. (Method 3) The aforementioned metal paste is applied to a mold measuring 4 mm in length, 20 mm in width, and 0.3 mm in thickness. The mold is heated at a constant rate from 30°C to 200°C over 60 minutes, and then heated at 200°C for 120 minutes to prepare a test specimen. The obtained test specimen is then subjected to a dynamic viscoelasticity analyzer in accordance with JIS K 6911:2006, under the conditions of tensile mode, heating rate: 5°C / min, and frequency: 1 Hz, to determine the storage modulus E' at 250°C. ２５０ Measure.

24. A metal paste according to any one of claims 1 to 5, wherein the glass transition temperature by the following method (4) is 70°C or more and 300°C or less. (Method 4) A test specimen is prepared by applying the metal paste to a mold measuring 4 mm in length, 10 mm in width, and 0.15 mm in thickness, and then heating it at a constant rate from 30°C to 200°C over 60 minutes, followed by heating it at 200°C for 120 minutes. Then, using a thermomechanical analyzer, the amount of expansion of the test specimen in relation to its temperature is detected as an electrical output by a differential transformer while the obtained test specimen is pulled with a load of 10 mN and its temperature is increased from -100°C to 330°C at a heating rate of 5°C / min, and a graph showing the amount of expansion of the test specimen in relation to its temperature is created. Then, the glass transition temperature (Tg) is determined from the inflection point of the graph.

25. The mean coefficient of linear expansion α according to the following (Method 5) １ A metal paste according to any one of claims 1 to 5, wherein the concentration is 10 ppm / °C or more and 100 ppm / °C or less. (Method 5) A test specimen is prepared by applying the metal paste to a mold measuring 4 mm in length, 10 mm in width, and 0.15 mm in thickness, and then heating it at a constant rate from 30°C to 200°C over 60 minutes, followed by heating it at 200°C for 120 minutes. Then, using a thermomechanical analyzer, the amount of expansion of the test specimen in relation to its temperature is detected as an electrical output by a differential transformer while the obtained test specimen is pulled with a load of 10 mN and its temperature is increased from -100°C to 330°C at a heating rate of 5°C / min, and a graph showing the amount of expansion of the test specimen in relation to its temperature is created. Then, the glass transition temperature (Tg) is determined from the inflection point of the graph. Furthermore, the average linear expansion coefficient α at temperatures below the calculated glass transition temperature (Tg) is calculated. １ Measure the concentration (ppm / °C).

26. The mean coefficient of linear expansion α calculated below (Method 6) ２ A metal paste according to any one of claims 1 to 5, wherein the concentration is 40 ppm / °C or more and 150 ppm / °C or less. (Method 6) A test specimen is prepared by applying the metal paste to a mold measuring 4 mm in length, 10 mm in width, and 0.15 mm in thickness, and then heating it at a constant rate from 30°C to 200°C over 60 minutes, followed by heating it at 200°C for 120 minutes. Then, using a thermomechanical analyzer, the amount of expansion of the test specimen in relation to its temperature is detected as an electrical output by a differential transformer while the obtained test specimen is pulled with a load of 10 mN and its temperature is increased from -100°C to 330°C at a heating rate of 5°C / min, and a graph showing the amount of expansion of the test specimen in relation to its temperature is created. Then, the glass transition temperature (Tg) is determined from the inflection point of the graph. Furthermore, the average linear expansion coefficient α at temperatures above the calculated glass transition temperature (Tg) is calculated. ２ Measure the concentration (ppm / °C).

27. A metal paste according to any one of claims 1 to 5, wherein the curing shrinkage rate by the method described below (Method 7) is 7.0% or less. (Method 7) The metal paste is applied to a silicon chip 1 measuring 7.0 mm in length and 7.0 mm in width. Then, a silicon chip 2 measuring 3.0 mm in length and 3.0 mm in width is placed on the metal paste. Next, a load of 100 N / (3.0 × 3.0 mm) is applied perpendicular to the surface of the silicon chip 2 to obtain a laminate. The thickness of the metal paste at this time is t ０ Let it be [μm]. Next, the laminate is placed in an electric furnace that has been sufficiently purged with nitrogen, and the temperature is raised at a constant rate from 30°C to 200°C over 60 minutes, followed by heat treatment at 200°C for 120 minutes to harden the metal paste. The thickness of the metal paste after hardening is t １ Let it be [μm]. t measured ０ [μm] and t １ Using [μm], the curing shrinkage rate is calculated according to JIS K 6941:2019 using the following formula (A). Hardening shrinkage rate (%) = ((t) ０ -t １ ) / t ０ ) × 100 (A)

28. A metal paste according to any one of claims 1 to 5, wherein the thermal conductivity according to the method (8) below is 10.0 W / m·K or more and 100.0 W / m·K or less. (Method 8) The metal paste is applied to a mold measuring 10 mm x 10 mm x 1.0 mm, and the temperature is raised at a constant rate from 30°C to 200°C over 60 minutes, followed by heating at 200°C for 120 minutes to prepare a test specimen. The thermal conductivity of the obtained test specimen is measured using a Xe flash analyzer, measuring the thermal diffusion coefficient (α) in the longitudinal direction of the test specimen by the laser flash method (half-time method) under atmospheric conditions and at 25°C. Furthermore, the specific heat (Cp) measured by the DSC method and the density (ρ) measured in accordance with JIS K 6911:2006 are used to calculate the thermal conductivity using the following formula. Thermal conductivity [W / m·K] = α [mm] ２ / s]×Cp[J / kg・K]×ρ[g / cm ３ ]

29. An electronic device comprising a cured product formed from a metal paste according to any one of claims 1 to 5.

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