Encapsulating resin composition and electronic device using same

Abstract

The present invention provides an encapsulating resin composition and electronic device that have an excellent balance of high Tg, adhesion, and high-temperature reliability. [Solution] The encapsulating resin composition of the present invention comprises an epoxy resin, a curing agent, and an inorganic filler, wherein the epoxy resin comprises an epoxy resin having 2 to 6 epoxy groups in the molecule, the curing agent comprises a compound having 2 or more active hydrogens in the molecule, and the equivalent ratio, which is the ratio of the epoxy equivalent of the epoxy resin to the active hydrogen equivalent of the curing agent, is 1.4 or more and 2.0 or less.

Description

[Technical Field]

[0001] The present invention relates to an encapsulating resin composition and an electronic device using the same. More specifically, the present invention relates to a resin composition for encapsulating electronic components such as semiconductors, and a device including electronic components encapsulated with such a resin composition. [Background technology]

[0002] BACKGROUND ART In recent years, from the viewpoint of effective utilization of electrical energy, SiC / GaN power semiconductor devices equipped with elements using SiC (silicon carbide) and GaN (gallium nitride) have been attracting attention (see, for example, Patent Document 1).

[0003] Such devices not only have significantly reduced power loss compared to conventional Si-based devices, but are also capable of operating at higher voltages, currents, and temperatures of 200°C or higher. Therefore, they are expected to be used in applications that were previously difficult to apply to conventional Si power semiconductor devices.

[0004] As such, elements that can operate under harsh conditions, such as elements (semiconductor elements) that use SiC / GaN, require semiconductor encapsulation materials that are provided in semiconductor devices to protect these elements and have higher heat resistance than conventional materials.

[0005] In conventional Si power semiconductor devices, a semiconductor encapsulant containing a cured product of an epoxy resin composition as a main material is used as the semiconductor encapsulant from the viewpoints of adhesiveness, electrical stability, etc.

[0006] The glass transition temperature (Tg) is generally used as an index of the heat resistance of the cured product of such a resin composition. This is because, at temperatures above Tg, the encapsulating resin composition (cured product) becomes rubbery, which reduces its strength and adhesive strength. Therefore, methods for increasing Tg include increasing the crosslink density by reducing the epoxy group equivalent of the epoxy resin contained in the resin composition or the hydroxyl group equivalent of the curing agent (phenolic resin curing agent), or by making the structure connecting these functional groups (epoxy groups and hydroxyl groups) more rigid.

[0007] On the other hand, when the present inventors investigated resin compositions using epoxy resins with high Tg as described above, it became clear that there was room for improvement in the results of the HAST test (High Accelerated Stress Test).

[0008] Therefore, in order to improve the heat resistance of a resin composition, it is desirable to realize a resin composition that has a high Tg, excellent adhesion, and excellent high-temperature reliability by designing the resin skeleton formed by the epoxy resin and the curing agent and the functional group density under optimal conditions. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-167035 Summary of the Invention [Problem to be solved by the invention]

[0010] In view of the above background, the present invention provides a resin composition capable of forming a semiconductor encapsulant having a high glass transition temperature and excellent adhesion and high-temperature reliability, and also provides an electronic device obtained by encapsulating an electronic component with such a resin composition. [Means for solving the problem]

[0011] As a result of investigations, the present inventors have completed the invention provided below and solved the above-mentioned problems.

[0012] According to the present invention, Contains an epoxy resin, a hardener and an inorganic filler, the epoxy resin includes an epoxy resin having 2 to 6 epoxy groups in the molecule, The curing agent contains a compound having two or more active hydrogen atoms in the molecule, The encapsulating resin composition has an equivalent ratio, which is the ratio of the epoxy equivalent of the epoxy resin to the active hydrogen equivalent of the curing agent, of 1.4 or more and 2.0 or less.

[0013] Further, according to the present invention, An electronic device is provided that includes an electronic component encapsulated with the encapsulating resin composition. [Effects of the Invention]

[0014] According to the present invention, there are provided an encapsulating resin composition and an electronic device which have an excellent balance of high Tg, adhesion and high-temperature reliability. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present invention will be described in detail based on the embodiments.

[0016] <Resin composition> First, the resin composition of the present embodiment will be described.

[0017] The resin composition of this embodiment comprises an epoxy resin, a curing agent, and an inorganic filler, wherein the epoxy resin comprises an epoxy resin having 2 to 6 epoxy groups per molecule, the curing agent comprises a compound having 2 or more active hydrogen atoms per molecule, and the lower limit of the equivalent ratio, which is the ratio of the epoxy equivalent of the epoxy resin to the active hydrogen equivalent of the curing agent, is preferably 1.4 or more, more preferably 1.5 or more, and even more preferably 1.6 or more. The upper limit of the equivalent ratio is preferably 2.0 or less, more preferably 1.85, and even more preferably 1.75.

[0018] By adjusting the amount of epoxy groups in the epoxy resin to fall within the above range, the crosslinking density between the epoxy resin and the curing agent is improved and becomes favorable, which inhibits the migration and reaction of free ions contained in the resin composition and prevents deterioration of the resin. In addition, by setting the amount of epoxy groups in the epoxy resin within the above range, the amount of remaining unreacted curing agent can be reduced, and the influence of polarization of the unreacted curing agent can be reduced.

[0019] Furthermore, by adjusting the amount of active hydrogen in the curing agent to fall within the above range, the crosslink density between the epoxy resin and the curing agent is improved, which is preferable, and this inhibits the migration and reaction of free ions contained in the resin composition, thereby preventing deterioration of the resin.

[0020] Furthermore, by setting the equivalent ratio at or above the lower limit, the amount of unreacted curing agent remaining can be reduced, reducing the effects of polarization of the unreacted curing agent. This also improves the crosslink density between the epoxy resin and the curing agent, resulting in a desirable result. This inhibits the migration and reaction of free ions contained in the resin composition, preventing resin degradation and improving the high-temperature reliability of the resin composition. Furthermore, by setting the equivalent ratio at or below the upper limit, the flowability of the resin composition can be improved. For example, when the resin composition of this embodiment is used to seal electronic components, the adhesion between the resin composition and the lead frame or substrate can be improved.

[0021] The epoxy equivalent of the epoxy resin can be measured according to JIS K 7236 and is the mass of the resin containing one equivalent of epoxy groups. In the present embodiment, when a mixture of multiple epoxy resins is used, the epoxy equivalent refers to the number of equivalents after mixing the multiple epoxy resins.

[0022] The active hydrogen equivalent is the number of functional groups having active hydrogen reactive with epoxy groups (hereinafter referred to as active hydrogen groups, including functional groups having latent active hydrogen that generates active hydrogen upon hydrolysis or the like, and functional groups that exhibit an equivalent curing action).

[0023] Specific examples of active hydrogen groups include acid anhydride groups, carboxyl groups, amino groups, and phenolic hydroxyl groups. Regarding active hydrogen groups, a carboxyl group (-COOH) or a phenolic hydroxyl group (-OH) is calculated as 1 mole, and an amino group (-NH2) is calculated as 2 moles. If the active hydrogen groups are unclear, the active hydrogen equivalent can be determined by measurement. For example, the active hydrogen equivalent of the curing agent used can be determined by reacting a monoepoxy resin with a known epoxy equivalent, such as phenyl glycidyl ether, with a curing agent with an unknown active hydrogen equivalent and measuring the amount of monoepoxy resin consumed.

[0024] In this embodiment, when a mixture of multiple curing agents is used, the active hydrogen equivalent is the number of equivalents after mixing the multiple curing agents.

[0025] Each component contained in the resin composition will be described below.

[0026] (epoxy resin) In this embodiment, the epoxy resin preferably contains a monomer represented by the following general formula (1).

[0027] [ka]

[0028] In this case, m and n represent the number of epoxy groups on the naphthalene ring, and each independently represents an integer of 1 to 3.

[0029] As the monomer of general formula (1), it is preferable to use one or more of the following:

[0030] [ka]

[0031] In addition to the epoxy resin represented by the general formula (1) above, known epoxy resins that are generally used in epoxy resin compositions for encapsulation can be used in this embodiment. Epoxidized novolac resins obtained by condensing or co-condensing phenols such as phenol novolac epoxy resins and orthocresol novolac epoxy resins, and / or naphthols such as α-naphthol, β-naphthol, and dihydroxynaphthalene with compounds having an aldehyde group such as formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde, and salicylaldehyde under an acidic catalyst; diglycidyl ethers of bisphenol A, bisphenol F, bisphenol S, and bisphenol A / D; biphenyl epoxy resins, which are diglycidyl ethers of alkyl-substituted or unsubstituted biphenols; phenol aralkyl resins synthesized from phenols and dimethoxy-paraxylene or bis(methoxymethyl)biphenyl; and biphenylene-skeleton phenols. glycidyl ester epoxy resins obtained by reacting epichlorohydrin with polybasic acids such as phthalic acid and dimer acid; glycidylamine epoxy resins obtained by reacting epichlorohydrin with polyamines such as diaminodiphenylmethane and isocyanuric acid; dicyclopentadiene epoxy resins which are epoxidized products of co-condensation resins of dicyclopentadiene and phenols; triphenolmethane epoxy resins, trimethylolpropane epoxy resins; terpene-modified epoxy resins; linear aliphatic epoxy resins obtained by oxidizing olefin bonds with peracids such as peracetic acid; alicyclic epoxy resins; and epoxy resins obtained by modifying these epoxy resins with silicone, acrylonitrile, butadiene, isoprene-based rubber, polyamide-based resin, or the like.

[0032] In one embodiment of the present invention, an epoxy resin containing a monomer represented by the general formula (1) may be used alone, or a known epoxy resin other than the monomer represented by the general formula (1) may be used alone, or one or more epoxy resins selected from the known epoxy resins may be mixed with an epoxy resin containing a monomer represented by the general formula (1).Of these, it is more preferable that the epoxy resin is a mixture of an epoxy resin containing a monomer represented by the general formula (1) and one or more epoxy resins different from the monomer.

[0033] In the present embodiment, the content of all epoxy resins in the encapsulating resin composition is preferably 5% by mass or more, more preferably 6% by mass or more, and even more preferably 7% by mass or more, based on the total amount of the encapsulating resin composition, from the viewpoints of realizing excellent fluidity and improving filling properties and adhesion during molding. In addition, from the viewpoint of improving the high-temperature reliability and reflow resistance of a semiconductor device obtained using the encapsulating resin composition, the content of all epoxy resins in the encapsulating resin composition is preferably 15 mass % or less, more preferably 14 mass % or less, and even more preferably 13 mass % or less, based on the total encapsulating resin composition.

[0034] In this embodiment, from the viewpoint of high-temperature reliability, it is preferable that the resin composition contains as few ionic impurities as possible, such as Na ions, Cl ions, and S ions.

[0035] In the present embodiment, the epoxy equivalent weight of all epoxy resins in the encapsulating resin composition is preferably 100 g / eq or more, more preferably 120 g / eq or more, and even more preferably 150 g / eq or more, from the viewpoints of realizing excellent fluidity and improving filling properties and adhesion during molding. Furthermore, from the viewpoint of improving the high-temperature reliability and reflow resistance of a semiconductor device obtained using the encapsulating resin composition, the epoxy equivalent of all epoxy resins in the encapsulating resin composition is preferably 500 g / eq or less, more preferably 480 g / eq or less, and even more preferably 450 g / eq or less.

[0036] (hardening agent) Examples of curing agents that can be used in this embodiment include known curing agents that are generally used in encapsulating epoxy resin compositions, such as phenol-based curing agents and amine-based curing agents (curing agents having an amino group).

[0037] Examples of phenol-based curing agents include novolak-type phenolic resins obtained by condensing or co-condensing phenols such as phenol, cresol, resorcinol, catechol, bisphenol A, bisphenol F, phenylphenol, and aminophenol, and / or naphthols such as α-naphthol, β-naphthol, and dihydroxynaphthalene, with compounds having an aldehyde group such as formaldehyde, benzaldehyde, and salicylaldehyde, under an acidic catalyst; polyfunctional phenolic resins such as triphenylmethane-type phenolic resins and biphenylene skeleton-containing polyfunctional phenolic resins; phenol aralkyl-type phenolic resins such as biphenylene skeleton-containing polyfunctional phenolic resins synthesized from phenols and / or naphthols and dimethoxyparaxylene or bis(methoxymethyl)biphenyl; dicyclopentadiene-type phenolic resins; and terpene-modified phenolic resins.

[0038] Examples of the amine curing agent include linear aliphatic diamines having 2 to 20 carbon atoms, such as ethylenediamine, trimethylenediamine, tetramethylenediamine, and hexamethylenediamine, metaphenylenediamine, paraphenylenediamine, paraxylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodicyclohexane, bis(4-aminophenyl)phenylmethane, 1,5-diaminonaphthalene, metaxylenediamine, paraxylenediamine, 1,1-bis(4-aminophenyl)cyclohexane, and dicyanodiamide.

[0039] Other curing agents include polyoxystyrenes such as polyparaoxystyrene; acid anhydrides including alicyclic acid anhydrides such as hexahydrophthalic anhydride (HHPA) and methyltetrahydrophthalic anhydride (MTHPA), and aromatic acid anhydrides such as trimellitic anhydride (TMA), pyromellitic anhydride (PMDA), and benzophenonetetracarboxylic acid (BTDA); polymercaptan compounds such as polysulfides, thioesters, and thioethers; isocyanate compounds such as isocyanate prepolymers and blocked isocyanates; and organic acids such as carboxylic acid-containing polyester resins.

[0040] Among these, from the viewpoints of adhesion and high-temperature reliability, the curing agent used in the semiconductor encapsulation resin composition preferably contains one or two of a polyfunctional phenolic resin and a phenol aralkyl phenolic resin, and more preferably contains a triphenylmethane phenolic resin or a biphenylene skeleton-containing polyfunctional phenolic resin. These may be used alone or in combination of two or more.

[0041] In the present embodiment, the content of the curing agent in the encapsulating resin composition is preferably 1% by mass or more, more preferably 2% by mass or more, and even more preferably 3% by mass or more, based on the total mass of the encapsulating resin composition, from the viewpoint of realizing excellent fluidity and improving filling properties and adhesion during molding. In addition, from the viewpoint of improving the high-temperature reliability and reflow resistance of a semiconductor device obtained using the encapsulating resin composition, the content of the curing agent in the encapsulating resin composition is preferably 25 mass % or less, more preferably 15 mass % or less, and even more preferably 10 mass % or less, based on the total encapsulating resin composition.

[0042] (Inorganic filler) The inorganic filler has the function of reducing the increase in moisture absorption and the decrease in strength that accompany the curing of the resin composition, and any inorganic filler that is generally used in this field can be used.

[0043] Examples of inorganic fillers include fused silica, spherical silica, crystalline silica, alumina, silicon nitride, and aluminum nitride, and these inorganic fillers may be used alone or in combination.

[0044] Average particle size D of inorganic filler 50 can be, for example, 0.01 μm or more and 150 μm or less.

[0045] The lower limit of the amount of inorganic filler in the resin composition is preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more, based on the total mass of the resin composition. When the lower limit is within the above range, the increase in moisture absorption and the decrease in strength that accompany curing of the resulting resin composition can be more effectively reduced, thereby further improving the solder crack resistance of the cured product.

[0046] The upper limit of the amount of inorganic filler in the resin composition is preferably 93% by mass or less, more preferably 91% by mass or less, and even more preferably 90% by mass or less, based on the total mass of the resin composition. When the upper limit is within the above range, the resulting resin composition has good fluidity and good moldability.

[0047] When inorganic flame retardants such as metal hydroxides such as aluminum hydroxide and magnesium hydroxide, zinc borate, zinc molybdate, and antimony trioxide are used, it is preferable that the total amount of these inorganic flame retardants and the inorganic filler be within the above range.

[0048] (Other ingredients) The resin composition of the present invention may contain the following components in addition to the curing agent, epoxy resin, and inorganic filler.

[0049] (curing accelerator) The curing accelerator has the function of accelerating the reaction between the epoxy group of the epoxy resin and the reactive group of the curing agent, and any curing accelerator generally used in this field can be used.

[0050] Specific examples of the curing accelerator include phosphorus-containing compounds such as organic phosphines, tetra-substituted phosphonium compounds, phosphobetaine compounds, adducts of phosphine compounds and quinone compounds, and adducts of phosphonium compounds and silane compounds; and nitrogen-containing compounds such as amidines and tertiary amines, exemplified by 1,8-diazabicyclo(5,4,0)undecene-7, benzyldimethylamine, and 2-methylimidazole, as well as quaternary salts of the amidines and amines. One or more of these compounds can be used in combination. Among these, phosphorus-containing compounds are preferred from the viewpoint of curability, and phosphobetaine compounds and adducts of phosphine compounds and quinone compounds are particularly preferred from the viewpoints of solder resistance and fluidity. Furthermore, phosphorus-containing compounds such as tetra-substituted phosphonium compounds and adducts of phosphonium compounds and silane compounds are particularly preferred because of their low mold contamination during continuous molding.

[0051] Examples of organic phosphines that can be used in the resin composition include primary phosphines such as ethylphosphine and phenylphosphine; secondary phosphines such as dimethylphosphine and diphenylphosphine; tertiary phosphines such as trimethylphosphine, triethylphosphine, tributylphosphine and triphenylphosphine; and derivatives thereof.

[0052] (coupling agent) The coupling agent has the function of improving the adhesion between the epoxy resin and the inorganic filler when the inorganic filler is contained in the resin composition, and for example, a silane coupling agent or the like is used.

[0053] Although various silane coupling agents can be used, it is preferable to use aminosilane, which can improve the flowability and solder resistance of the resin composition.

[0054] The aminosilane is not particularly limited, but examples thereof include γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-β(aminoethyl)γ-aminopropyltrimethoxysilane, N-β(aminoethyl)γ-aminopropylmethyldimethoxysilane, N-phenylγ-aminopropyltriethoxysilane, N-phenylγ-aminopropyltrimethoxysilane, N-β(aminoethyl)γ-aminopropyltriethoxysilane, N-6-(aminohexyl)3-aminopropyltrimethoxysilane, and N-(3-(trimethoxysilylpropyl)-1,3-benzenedimethanamine).

[0055] The lower limit of the blending ratio of the coupling agent, such as a silane coupling agent, is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and particularly preferably 0.1% by mass or more, based on the total resin composition. If the lower limit of the blending ratio of the coupling agent, such as a silane coupling agent, is within the above range, the interfacial strength between the epoxy resin and the inorganic filler is not reduced, and good solder crack resistance can be obtained in electronic devices. Furthermore, the upper limit of the blending ratio of the coupling agent, such as a silane coupling agent, is preferably 1% by mass or less, more preferably 0.8% by mass or less, and particularly preferably 0.6% by mass or less, based on the total resin composition. If the upper limit of the blending ratio of the coupling agent, such as a silane coupling agent, is within the above range, the interfacial strength between the epoxy resin and the inorganic filler is not reduced, and good solder crack resistance can be obtained in devices. Furthermore, if the blending ratio of the coupling agent, such as a silane coupling agent, is within the above range, the water absorption of the cured resin composition is not increased, and good solder crack resistance can be obtained in electronic devices.

[0056] (inorganic flame retardants) The inorganic flame retardant has the function of improving the flame retardancy of the resin composition, and any commonly used inorganic flame retardant can be used.

[0057] Specifically, metal hydroxides that inhibit the combustion reaction by dehydrating and absorbing heat during combustion, and composite metal hydroxides that can shorten the combustion time are preferably used.

[0058] Examples of metal hydroxides include aluminum hydroxide, magnesium hydroxide, calcium hydroxide, barium hydroxide, and zirconia hydroxide.

[0059] The complex metal hydroxide is a hydrotalcite compound containing two or more metal elements, where at least one of the metal elements is magnesium and the other metal elements are selected from calcium, aluminum, tin, titanium, iron, cobalt, nickel, copper, and zinc. As such a complex metal hydroxide, a magnesium-zinc hydroxide solid solution is readily available as a commercial product.

[0060] Among these, aluminum hydroxide and magnesium-zinc hydroxide solid solution are preferred from the viewpoint of the balance between adhesion and high-temperature reliability.

[0061] The inorganic flame retardants may be used alone or in combination of two or more. In order to reduce the influence on adhesion, the inorganic flame retardants may be surface-treated with a silicon compound such as a silane coupling agent or an aliphatic compound such as wax.

[0062] In the present invention, although it is permissible to use the inorganic flame retardants, it is preferable not to use flame retardants whose weight loss after treatment relative to the initial weight is 0.1% by weight or more when the inorganic flame retardant is dried at 125°C for 20 hours, cooled in a desiccator, and then placed in a high-temperature bath at 200°C for 1000 hours, and the weight after cooling in the desiccator is taken as the post-treatment weight.Furthermore, it is desirable not to use inorganic flame retardants, and to compose the resin composition using only flame-retardant resins.

[0063] That is, in the resin composition of the present invention, the epoxy resin contains an epoxy resin having 2 to 6 epoxy groups in the molecule, the curing agent contains a compound having 2 or more active hydrogen atoms in the molecule, and the equivalent ratio, which is the ratio of the epoxy equivalent of the epoxy resin to the active hydrogen equivalent of the curing agent, is 1.4 to 2.0, so that the resin composition has high flame retardancy and also functions as a flame retardant. Therefore, even if the blending of a metal hydroxide-based flame retardant, which may release water at high temperatures of 200°C or higher and result in an increase in the weight loss rate of the cured product, is omitted, the resin composition can be imparted with properties similar to those obtained when a flame retardant is added.

[0064] In addition to the other components described above, colorants such as carbon black, red iron oxide, and titanium oxide; ion scavengers; natural waxes such as carnauba wax, synthetic waxes such as polyethylene wax, release agents such as higher fatty acids such as stearic acid and zinc stearate, and metal salts thereof, or paraffin; and low-stress additives such as silicone oil and silicone rubber may also be blended as appropriate.

[0065] The resin composition of the present invention can be obtained by mixing the above-mentioned curing agent and epoxy resin, and, if necessary, the above-mentioned other components, by a method commonly used in the relevant field.

[0066] In one embodiment of the present invention, the lower limit of the glass transition temperature (Tg) of the encapsulating resin composition measured by thermomechanical analysis (TMA) under conditions of a heating rate of 5°C / min and a measurement mode of compression is preferably 190°C, more preferably 200°C, and even more preferably 210°C. In this case, the measurement start temperature is not particularly limited, but is, for example, 25°C. When the Tg is equal to or greater than the above lower limit, for example, when the resin composition of the present embodiment is used to encapsulate an electronic component, it is possible to prevent a decrease in the strength of the cured resin composition during high-temperature treatment such as reflow treatment, and a decrease in the adhesive strength between the resin composition and a lead frame or a substrate, thereby improving high-temperature reliability.

[0067] The upper limit of the glass transition temperature (Tg) of the encapsulating resin composition is preferably 330° C., more preferably 290° C., and even more preferably 250° C. When the resin composition of the present embodiment is used to encapsulate electronic components, for example, the elastic modulus of the cured product of the resin composition does not become too high, which is advantageous for stress relaxation during encapsulation.

[0068] In one embodiment of the present invention, the lower limit of the water absorption of the resin composition measured in accordance with JIS K 7209 is preferably 0%, more preferably 0.1%, and even more preferably 0.28%. When the resin composition of the present embodiment has a water absorption rate of at least the above lower limit, for example, when the resin composition is used to seal electronic components, the resin composition exhibits excellent adhesion to a lead frame or a substrate. The upper limit of the water absorption is preferably 0.6%, more preferably 0.4%, and even more preferably 0.32%. When the water absorption rate is equal to or less than the upper limit, for example, when the resin composition of the present embodiment is used to seal electronic components, it is possible to obtain excellent high-temperature reliability and good solder crack resistance in the device.

[0069] In one embodiment of the present invention, the resin composition is heat-treated at 175°C for 120 seconds, and then at 200°C for 4 hours to obtain a cured product, which has a storage modulus E' at 300°C when measured using a dynamic viscoelasticity measuring device. 300 and storage modulus E' at 350°C 350 The ratio E' 300 / E' 350 The lower limit of the ratio E' is preferably 1.4, more preferably 1.45, and even more preferably 1.5. 300 / E' 350 When the resin composition of the present embodiment is used to seal electronic components, for example, the resin composition has excellent adhesion to a lead frame or a substrate, since the resin composition has a viscosity of not less than the lower limit. Also, the above E' 300 / E' 350 The upper limit of the ratio E' is preferably 2.0, more preferably 1.95, and even more preferably 1.9. 300 / E' 350 When the resin composition of the present embodiment is used for sealing electronic components, for example, by making the resin composition of the present embodiment equal to or less than the upper limit, excellent high-temperature reliability and good solder crack resistance in the device can be obtained.

[0070] In one embodiment of the present invention, the resin composition is heat-treated at 175°C for 120 seconds, and then at 200°C for 4 hours to obtain a cured product, which has a storage modulus E' at 350°C when measured using a dynamic viscoelasticity measuring device. 350 and storage modulus E' at 400°C 400 The ratio E' 350 / E' 400 The lower limit of the ratio E' is preferably 1.4, more preferably 1.5, and even more preferably 1.6. 350 / E' 400 When the resin composition of the present embodiment is used to seal electronic components, for example, the resin composition has excellent adhesion to a lead frame or a substrate, since the resin composition has a viscosity of not less than the lower limit. Also, the above E' 350 / E' 400 The upper limit of the ratio E' is preferably 2.0, more preferably 1.9, and even more preferably 1.8. 350 / E' 400 When the resin composition of the present embodiment is used for sealing electronic components, for example, by making the resin composition of the present embodiment equal to or less than the upper limit, excellent high-temperature reliability and good solder crack resistance in the device can be obtained.

[0071] In one embodiment of the present invention, in a graph where the vertical axis represents tan δ measured using a dynamic viscoelasticity measuring device under conditions of a heating rate of 5°C / min, a frequency of 10 Hz, and a measurement mode of compression, and the horizontal axis represents temperature (°C), the inflection point where the value of tan δ changes from decreasing to increasing is preferably at or above the glass transition temperature, more preferably at or above 310°C, and even more preferably at or above 320°C. By having the above characteristics, when the resin composition of this embodiment is used, for example, to seal electronic components, the resin composition exhibits excellent adhesion to a lead frame or a substrate. The inflection point is preferably 400° C. or lower, more preferably 390° C. or lower, and even more preferably 380° C. or lower. By having the above characteristics, when the resin composition of the present embodiment is used for sealing electronic components, for example, it is possible to obtain excellent high-temperature reliability and good solder crack resistance in the device.

[0072] The reason for this form is not clear, but in this embodiment, the equivalent ratio, which is the ratio of the epoxy equivalent of the epoxy resin to the active hydrogen equivalent of the curing agent, is higher than in the past, and the form is epoxy-rich. Therefore, it does not become a rubber-like elastic body even in a temperature range that would be the rubber-like elastic region for a conventional resin composition, and it is thought that tan δ increases.

[0073] Next, the shape of the encapsulating resin composition will be described. In the present embodiment, the shape of the encapsulating resin composition can be selected depending on the molding method of the encapsulating resin composition, and examples thereof include particulate shapes such as tablets, powders, and granules; and sheets.

[0074] The encapsulating resin composition can be produced, for example, by mixing the above-described components by known means, melt-kneading them in a kneading machine such as a roll, a kneader, or an extruder, cooling, and then pulverizing them. After pulverization, the resulting mixture may be molded to obtain a particulate or sheet-like encapsulating resin composition. For example, the particulate encapsulating resin composition may be molded into tablets. Alternatively, a sheet-like encapsulating resin composition may be obtained using a vacuum extruder. The degree of dispersion, flowability, and the like of the obtained encapsulating resin composition may be adjusted as appropriate.

[0075] The encapsulating resin composition obtained in this embodiment has a high glass transition temperature and therefore has excellent adhesion to metal members. More specifically, this embodiment also makes it possible to improve adhesion between the encapsulating material and a member made of Ag, Ni, Cu, or an alloy containing one or more of these elements. Furthermore, by using the encapsulating resin composition obtained in this embodiment, a semiconductor device with excellent high-temperature reliability can be obtained.

[0076] In one embodiment of the present invention, the encapsulating resin composition can be used to encapsulate electronic components to produce electronic devices. While the encapsulating resin composition can be used for any known electronic device, it is preferable to use the composition in a semiconductor package that encapsulates a semiconductor chip. A preferred embodiment of the semiconductor chip is a semiconductor chip made of silicon carbide (SiC) and gallium nitride (GaN).

[0077] In this embodiment, the electronic device of the present invention can be applied to various known types of semiconductor packages, such as dual in-line packages (DIPs), plastic leaded chip carriers (PLCCs), quad flat packages (QFPs), low profile quad flat packages (LQFPs), small outline packages (SOPs), small outline J-lead packages (SOJs), thin small outline packages (TSOPs), thin quad flat packages (TQFPs), tape carrier packages (TCPs), ball grid arrays (BGAs), chip size packages (CSPs), matrix array package ball grid arrays (MAPBGAs), and chip stacked chip size packages, which are used for memory and logic elements. The electronic device can also be preferably applied to packages such as TO-220s that mount power elements such as power transistors.

[0078] Although the resin composition and electronic device of the present invention have been described above, the present invention is not limited thereto.

[0079] For example, any component capable of exerting the same function may be added to the resin composition of the present invention.

[0080] Furthermore, the configuration of each part of the electronic device of the present invention can be replaced with any other component that can perform the same function, or any other component can be added. [Example]

[0081] <Examples and Comparative Examples> (Preparation of encapsulating resin composition) For each of the Examples and Comparative Examples, an encapsulating resin composition was prepared as follows. First, the components shown in Table 1 were mixed in a mixer. Then, the resulting mixture was roll-kneaded, cooled, and pulverized to obtain an encapsulating resin composition in the form of a powder or granule. Details of each component in Table 1 are as follows: The blending ratio of each component shown in Table 1 indicates the blending ratio (mass %) relative to the entire resin composition. (raw materials) (Inorganic filler) Inorganic filler 1: fused silica (FB-560, manufactured by Denka Co., Ltd., average particle size: 30 μm) Inorganic filler 2: fused silica (FB-105, manufactured by Denka, average particle size: 10 μm)

[0082] (coloring agent) Colorant 1: Carbon black (Carbon #5, manufactured by Mitsubishi Chemical Corporation)

[0083] (Silane coupling agent) Silane coupling agent 1: phenylaminopropyltrimethoxysilane (CF4083, manufactured by Dow Corning Toray Co., Ltd.)

[0084] (epoxy resin) Epoxy resin 1: Multifunctional epoxy resin (YL6677, manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: 163 g / eq) Epoxy resin 2: multifunctional epoxy resin (HP-4700-RC, manufactured by DIC Corporation, epoxy equivalent: 156 g / eq, epoxy resin containing a monomer represented by general formula (1) (m = n = 2))

[0085] (hardening agent) Curing agent 1: Triphenylmethane type phenolic resin (HE910-20, manufactured by Air Water, active hydrogen equivalent: 101) Curing agent 2: Biphenylene skeleton-containing polyfunctional phenolic resin (active hydrogen equivalent: 135) represented by the following formula (2)

[0086] [ka]

[0087] In formula (2), two Ys each independently represent a hydroxyphenyl group represented by formula (2-1) or (2-2), and X represents a hydroxyphenylene group represented by formula (2-3) or (2-4), where n represents an integer of 0 to 10.

[0088] [ka]

[0089] The above curing agent 2 was synthesized by the following method. A separable flask was equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen inlet, and 291 parts by mass of 1,3-dihydroxybenzene (Tokyo Chemical Industry Co., Ltd., "Resorcinol," melting point 111°C, molecular weight 110, purity 99.4%), 235 parts by mass of phenol (Kanto Chemical Co., Ltd., special grade reagent, "Phenol," melting point 41°C, molecular weight 94, purity 99.3%), and 125 parts by mass of 4,4'-bischloromethylbiphenyl (Wako Pure Chemical Industries, Ltd., "4,4'-bischloromethylbiphenyl," melting point 126°C, purity 95%, molecular weight 251) that had been crushed into granules were weighed into the separable flask, and the mixture was heated while replacing with nitrogen. Stirring began as the phenol began to melt.

[0090] Thereafter, the reaction was carried out for 3 hours while maintaining the temperature in the system in the range of 110 to 130°C, and then the system was heated and the reaction was carried out for 3 hours while maintaining the temperature in the range of 140 to 160°C.

[0091] The hydrochloric acid gas generated in the system by the above reaction was discharged outside the system by a nitrogen stream.

[0092] After the reaction was completed, unreacted components were distilled off under reduced pressure conditions of 150°C and 2 mmHg. Next, 400 parts by mass of toluene was added and dissolved uniformly, then transferred to a separatory funnel, 150 parts by mass of distilled water was added, and the mixture was shaken. The aqueous layer was then discarded (water washing), and this procedure was repeated until the washing water became neutral. The oil layer was then subjected to reduced pressure treatment at 125°C to distill off volatile components such as toluene and residual unreacted components, thereby obtaining curing agent 2 (polymer) represented by the above formula (2). The hydroxyl equivalent weight of this curing agent 2 was 135.

[0093] (curing accelerator) Curing accelerator 1: 4-hydroxy-2-(triphenylphosphonium)phenolate

[0094] (mold release agent) Release agent 1: Carnauba wax (TOWAX-132, manufactured by Toagosei Co., Ltd.)

[0095] (ion scavenger) Ion scavenger 1: Ion scavenger (DHT-4H, manufactured by Kyowa Chemical Industry Co., Ltd.) (low stress agent) Low-stress agent 1: Silicone oil (FZ-3730, manufactured by Dow Corning Toray Co., Ltd.)

[0096] (Physical property evaluation) The physical properties of the resin compositions obtained in each example were evaluated by the following methods.

[0097] (Spiral Flow (SF) Gel Time) Using a low-pressure transfer molding machine (Kotaki Seiki Co., Ltd., "KTS-15"), the resin compositions of each Example and Comparative Example were injected into a spiral flow measurement mold conforming to ANSI / ASTM D 3123-72 under conditions of 175°C, injection pressure of 6.9 MPa, and a dwell time of 120 seconds, and the flow length was measured as the spiral flow. The time from the start of injection until the resin composition hardened and no longer flowed was measured as the gel time. The spiral flow is a parameter of fluidity, and the larger the value, the better the fluidity.

[0098] (glass transition temperature (Tg), TMA) The glass transition temperatures of the resin compositions of each Example and Comparative Example were measured in accordance with JIS K 6911. Specifically, for each resin composition of each Example and Comparative Example, a transfer molding machine was used to mold 80 mm × 10 mm × 4 mm test pieces at a mold temperature of 175°C, an injection pressure of 6.9 MPa, and a curing time of 90 seconds. The test pieces were then post-cured at 175°C for 2 hours, and the thermal expansion coefficients of the test pieces were measured at a heating rate of 5°C / min using a thermomechanical analyzer (Seiko Instruments Inc., TMA / SS6000). The glass transition temperature (Tg) of the cured product was then calculated from the inflection point of the thermal expansion coefficient based on the measurement results.

[0099] (storage modulus, tanδ, DMA) The storage modulus E' of the resin composition of each Example and Comparative Example was measured by the following method: For each resin composition of each Example and Comparative Example, a test piece of 80 mm × 10 mm × 4 mm was molded using a transfer molding machine at a mold temperature of 175°C, an injection pressure of 6.9 MPa, and a curing time of 120 seconds, and post-cured at 200°C for 4 hours. The storage modulus and tan δ were then measured using a dynamic viscoelasticity measuring device (manufactured by A&D Co., Ltd., "DDV-25GP") (heating rate: 5°C / min, frequency: 10 Hz, load: 800 g). In each example, in a graph with measured tan δ on the vertical axis and temperature (°C) on the horizontal axis, an inflection point where the tan δ value changes from decreasing to increasing was found between the glass transition temperature and 400°C, whereas each comparative example did not have such an inflection point.

[0100] (flexural modulus, flexural strength) The resin composition was injected into a low-pressure transfer molding machine (KTS-30, manufactured by Kotaki Seiki Co., Ltd.) at a mold temperature of 175°C, an injection pressure of 9.8 MPa, and a cure time of 120 seconds to obtain a molded product measuring 80 mm in length, 10 mm in width, and 4 mm in thickness. The molded product was post-cured by heat treatment at 200°C for 4 hours to prepare test specimens, and the flexural modulus and flexural strength were measured at ambient temperatures of 25°C and 260°C in accordance with JIS K 6911.

[0101] (Water absorption rate) Using a low-pressure transfer molding machine (KTS-30, manufactured by Kotaki Seiki Co., Ltd.), the resin composition was injected and molded under conditions of a mold temperature of 175°C, an injection pressure of 7.4 MP, and a curing time of 120 seconds to prepare test pieces with a diameter of 50 mm and a thickness of 3 mm, which were then post-cured at 200°C for 4 hours. The obtained test pieces were then humidified in a boiling environment for 24 hours, and the change in weight before and after the humidification treatment was measured to determine the water absorption rate.

[0102] (evaluation) Using the resin composition obtained in each example, an evaluation sample was prepared by the following method, and the reliability of the obtained sample was evaluated by the following method.

[0103] (High temperature reliability: HAST test) The encapsulating resin composition obtained in each example was used in a low-pressure transfer molding machine (Apic Yamada's "MSL-06M") to mold a 16pSOP (Cu wire) at a mold temperature of 175°C, injection pressure of 10 MPa, and curing time of 180 seconds. Test semiconductor devices were then fabricated by curing at 200°C for 4 hours. The encapsulated test semiconductor devices were placed in an environment of 130°C, 85% RH, and 20 V, and the resistance was measured every 40 hours up to 240 hours. A resistance value of 1.2 times or more the initial value was considered a failure, a passing value of 200 hours or more was considered a "good," and a failing value before 200 hours was considered an "x."

[0104] [Table 1]

[0105] In the examples, it was possible to provide an encapsulating resin composition having a high glass transition temperature (Tg) and showing good results in the HAST test, and having excellent adhesion and high-temperature reliability.

[0106] This application claims priority based on Japanese Patent Application No. 2021-060421, filed on March 31, 2021, the disclosure of which is incorporated herein in its entirety.

Claims

1. Contains epoxy resin, hardener (but excluding hardening accelerator), and inorganic filler, the epoxy resin includes an epoxy resin having 2 to 6 epoxy groups in a molecule, the curing agent contains a compound having two or more active hydrogen atoms in the molecule, an equivalent ratio, which is a ratio of an epoxy equivalent of the epoxy resin to an active hydrogen equivalent of the curing agent, of 1.45 or more and 1.60 or less, a total content of epoxy resins in the encapsulating resin composition is 15% by mass or less based on the total mass of the encapsulating resin composition; the content of the curing agent in the encapsulating resin composition is 3% by mass or more and 10% by mass or less with respect to the entire encapsulating resin composition, The encapsulating resin composition, wherein the curing agent comprises a triphenylmethane-type phenolic resin or a biphenylene skeleton-containing polyfunctional phenolic resin.

2. The encapsulating resin composition according to claim 1, The encapsulating resin composition includes an epoxy resin containing a monomer represented by the following general formula (1): 【Chemistry 1】 (In the general formula (1), m and n represent the number of epoxy groups on the naphthalene ring, and each independently represents an integer of 1 to 3.)

3. The encapsulating resin composition according to claim 2, the epoxy resin is a mixture of an epoxy resin containing a monomer represented by general formula (1) and one or more epoxy resins different from the monomer;

4. The encapsulating resin composition according to any one of claims 1 to 3, The encapsulating resin composition, wherein the curing agent contains one or two of a polyfunctional phenol resin and a phenol aralkyl phenol resin.

5. The encapsulating resin composition according to any one of claims 1 to 4, An encapsulating resin composition, wherein the encapsulating resin composition has a glass transition temperature of 190°C or higher and 330°C or lower, as measured by thermomechanical analysis (TMA) at a temperature rise rate of 5°C / min.

6. The encapsulating resin composition according to any one of claims 1 to 5, An encapsulating resin composition having a water absorption rate of 0.6% or less as measured in accordance with JIS K 7209.

7. The encapsulating resin composition according to any one of claims 1 to 6, The encapsulating resin composition was heat-treated at 175°C for 120 seconds, and then at 200°C for 4 hours to obtain a cured product. The storage modulus E' at 300°C was measured using a dynamic viscoelasticity measuring device. ３００ and storage modulus E' at 350 ° C. ３５０ The ratio E' ３００ / E' ３５０ The encapsulating resin composition of claim 1, wherein the σ is 1.4 or more and 2.0 or less.

8. The encapsulating resin composition according to any one of claims 1 to 7, The encapsulating resin composition was heat-treated at 175°C for 120 seconds, and then at 200°C for 4 hours to obtain a cured product. The storage modulus E' at 350°C was measured using a dynamic viscoelasticity measuring device. ３５０ and storage modulus E' at 400 ° C. ４００ The ratio E' ３５０ / E' ４００ The encapsulating resin composition of claim 1, wherein the σ is 1.4 or more and 2.0 or less.

9. The encapsulating resin composition according to any one of claims 1 to 8, The encapsulating resin composition has an inflection point, where the tan δ value changes from decreasing to increasing, in a temperature range from the glass transition temperature to 400°C in a graph where the vertical axis represents tan δ measured using a dynamic viscoelasticity measuring device under conditions of a heating rate of 5°C / min, a frequency of 10 Hz, and a measurement mode of compression, and the horizontal axis represents temperature (°C).

10. An electronic device comprising an electronic component encapsulated with the encapsulating resin composition according to any one of claims 1 to 9.

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