Copolymer, modifier for semiconductor sealing, and semiconductor sealing material composition

Abstract

To provide a semiconductor sealing material composition that enables formation of a semiconductor sealing material having low thermal expansion suitable for miniaturization and thinning, and excellent water resistance, the semiconductor sealing material composition having superior melt fluidity during heating.SOLUTION: A copolymer has a weight-average molecular weight of 1000 to 100000, and comprises as constituent monomers 20 to 40 mass% of monomer (a) represented by formula (1), 10 to 50 mass% of monomer (b) represented by formula (2), and 30 to 50 mass% of monomer (c) having a maleimide skeleton. Formula (1): CH2=CR1-COO-(AO)n-H (1). (In formula (1), R1 represents a hydrogen atom or a methyl group; AO represents at least one oxyalkylene group having 2 to 4 carbon atoms; and n represents an average number of moles of added oxyalkylene groups and is a number of 5 to 100). Formula (2): CH2=CR2-COO-R3 (2). (In formula (2), R2 represents a hydrogen atom or a methyl group, and R3 represents an alkyl group having 1 to 4 carbon atoms).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a copolymer, a modifier for semiconductor encapsulation, and a semiconductor encapsulant composition. [Background technology]

[0002] In recent years, remarkable progress has been made in the integration of semiconductor elements, creating a demand for smaller and thinner packages. However, the smaller and thinner the package, the more susceptible it is to moisture in high-temperature, high-humidity environments, which can cause dimensional changes and a decrease in package strength, leading to a decline in the functionality of the semiconductor element. Therefore, semiconductor encapsulation materials with excellent water resistance are required for smaller and thinner packages. In addition, there is a risk of warping due to thermal expansion, so low expansion coefficients are also required.

[0003] As a means of obtaining an encapsulant for housing an optical semiconductor element with excellent water resistance, a method using an epoxy resin having an epoxy equivalent weight within a specific range and a phenolic resin having a hydroxyl equivalent weight within a specific range has been proposed (Patent Document 1). This method makes it possible to exhibit excellent water resistance and moldability. However, it is difficult to say that sufficient consideration has been given to low thermal expansion.

[0004] A common method for achieving a low coefficient of expansion is to add a silicone-based component with a low modulus of elasticity. However, silicone-based components have low affinity with epoxy resins and are difficult to mix with. Therefore, methods such as using a triblock copolymer in which polyalkylene glycol chains, which have high affinity with epoxy, are attached to both ends of the silicone-based component polydimethylsiloxane (Patent Document 2) and using a polyimide block copolymer in which imide bonds are introduced into the silicone-based component polysiloxane and polyalkylene glycol skeletons (Patent Document 3) have been proposed, which have made it possible to achieve excellent low thermal expansion. However, the addition of a copolymer incorporating a silicone-based component tends to reduce fluidity, making it difficult to achieve excellent moldability while maintaining sufficiently low thermal expansion to accommodate smaller and thinner products. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-292734 [Patent Document 2] Japanese Patent Application Publication No. 10-182831 [Patent Document 3] Japanese Patent Publication No. 2022-138123 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a semiconductor encapsulant composition that has sufficiently low thermal expansion to accommodate miniaturization and thinning, is capable of forming a semiconductor encapsulant that is excellent in water resistance, and has excellent fluidity when heated. [Means for solving the problem]

[0007] As a result of investigations aimed at solving the above problems, the present inventors have found that the above problems can be solved by using a specific copolymer. That is, the present invention relates to the following [1] to [3].

[0008] [1] The composition contains, as constituent monomers, 20 to 40 mass% of a polyalkylene glycol monomer (a) represented by the following general formula (1), 10 to 50 mass% of an alkyl ester monomer (b) represented by the following general formula (2), and 30 to 50 mass% of a monomer (c) having a maleimide skeleton, A copolymer having a weight average molecular weight of 1,000 to 100,000. General formula (1): CH2=CR 1 -COO-(AO) n -H (1) (In formula (1), R 1 represents a hydrogen atom or a methyl group, AO represents at least one oxyalkylene group having 2 to 4 carbon atoms, and n represents the average number of moles of oxyalkylene groups added, which is a number from 5 to 100. General formula (2): CH2=CR 2 -COO-R 3 ···(2) (In formula (2), R 2 represents a hydrogen atom or a methyl group, and R 3 represents an alkyl group having 1 to 4 carbon atoms. [2] A modifier for semiconductor encapsulation, comprising the copolymer according to [1] above. [3] A semiconductor encapsulant composition containing the semiconductor encapsulation modifier according to [2] above, wherein the semiconductor encapsulant composition contains 0.1 to 5 mass % of the semiconductor encapsulation modifier according to [2] above, 1 to 15 mass % of an epoxy resin, 1 to 15 mass % of a curing agent, and 63 to 97 mass % of a filler, when the entire semiconductor encapsulant composition is taken as 100 mass %. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a semiconductor encapsulant composition that has sufficiently low thermal expansion to meet the demands of smaller and thinner devices, is capable of forming a semiconductor encapsulant that is excellent in water resistance, and has excellent fluidity when heated. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 2 is a schematic diagram illustrating an example of a chromatogram obtained by gel permeation chromatography using a differential refractometer, which is used when measuring the molecular weight distribution of the polyalkylene glycol monomer (a) according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] In this specification, "(meth)acrylic" is a generic term that includes acrylic and methacrylic, "(meth)acrylate" is a generic term that includes acrylate and methacrylate, and "(meth)acrylonitrile" is a generic term that includes acrylonitrile and methacrylonitrile.

[0012] Hereinafter, an embodiment of the present invention will be described.

[0013] [Copolymer] The copolymer according to an embodiment of the present invention contains, as constituent monomers, 20 to 40% by mass of polyalkylene glycol monomer (a) (hereinafter sometimes simply referred to as "monomer (a)") represented by the following general formula (1), 10 to 50% by mass of alkyl ester monomer (b) (hereinafter sometimes simply referred to as "monomer (b)") represented by the following general formula (2), and 30 to 50% by mass of monomer (c) having a maleimide skeleton (hereinafter sometimes simply referred to as "monomer (c)"). The weight-average molecular weight of the copolymer is 1,000 to 100,000.

[0014] General formula (1): CH2=CR 1 -COO-(AO) n -H (1) (In formula (1), R 1 represents a hydrogen atom or a methyl group, AO represents at least one oxyalkylene group having 2 to 4 carbon atoms, and n represents the average number of moles of oxyalkylene groups added, which is a number from 5 to 100.

[0015] General formula (2): CH2=CR 2 -COO-R 3 ···(2) (In formula (2), R 2 represents a hydrogen atom or a methyl group, and R 3 represents an alkyl group having 1 to 4 carbon atoms.

[0016] The copolymer according to the embodiment of the present invention may be composed of constituent monomers consisting of monomers (a) to (c), i.e., composed only of constituent units derived from monomers (a) to (c), or may be composed of constituent monomers consisting of constituent units derived from monomers (a) to (c) and another copolymerizable monomer (hereinafter simply referred to as "monomer (d)"), i.e., composed of constituent units derived from monomers (a) to (d). The copolymer may be in any form such as a random copolymer, a block copolymer, an alternating copolymer, etc. A random copolymer is particularly preferred.

[0017] Each monomer will be described below.

[0018] [Monomer (a)] The monomer (a) used in the embodiment of the present invention may be a polyalkylene glycol monomer represented by the general formula (1), more specifically, a polyalkylene glycol mono(meth)acrylate. When the copolymer according to the embodiment of the present invention contains such a monomer (a) as a constituent monomer, it becomes possible to impart good fluidity to compositions containing epoxy resins, such as the semiconductor encapsulant composition described below, upon heating. The monomer (a) may be used singly or in combination of two or more.

[0019] In formula (1), R 1 may be a hydrogen atom or a methyl group, and is preferably a methyl group from the viewpoint of ease of polymerization.

[0020] In formula (1), AO may be at least one oxyalkylene group having 2 to 4 carbon atoms. That is, it may be one or more selected from the group consisting of an oxyethylene group, an oxypropylene group, and an oxybutylene group. An oxyethylene group and / or an oxypropylene group is preferred, and an oxypropylene group is more preferred. If two or more AOs are present, (AO) n The addition may be in a block or random form.

[0021] In formula (1), n ​​is the average number of moles of oxyalkylene groups added, and may be a number from 5 to 100. From the viewpoint of improving the flowability of the semiconductor encapsulant composition, n is preferably 5 to 60, more preferably 5 to 50, and even more preferably 5 to 40.

[0022] The molecular weight of the monomer (a) was calculated from the hydroxyl value measured in accordance with JIS K 1557-1.

[0023] Regarding the molecular weight distribution of the monomer (a), from the viewpoint of the fluidity of the semiconductor encapsulant composition, w calculated from a chromatogram (vertical axis: refractive index intensity, horizontal axis: retention time (t). See the schematic diagram shown in Figure 1 for an example) obtained by gel permeation chromatography (GPC) measurement using a differential refractometer. b and w f The ratio of b / w f However, it is preferable that the relationship of the following formula (Y) is satisfied.

[0024] 0.25≦w b / w f ≦0.90 (Y)

[0025] In the formula (Y), the retention time at the maximum peak height (h) of the peak in the chromatogram obtained by the GPC measurement using the differential refractometer is t h and 1 / 10 of the maximum peak height (h 1 / 10 ) two retention times at t f and t b (However, t f <t h <t b ), then w f =t h -t f , w b =t b -t h is.

[0026] Monomer (a) w b / w f If w is less than 0.25, the molecular weight distribution of the monomer (a) will be biased to the high molecular weight side, the concentration of the polymerizable functional group will be low, and the polymerizability of the monomer (a) may be reduced. b / w f is more preferably 0.30 or more, and even more preferably 0.35 or more.

[0027] On the other hand, the w of monomer (a) b / w fIf w is greater than 0.90, the monomer (a) itself and the reaction solution containing the monomer (a) are likely to gel. b / w f If w is greater than 0.90, the molecular weight distribution of the copolymer containing the monomer (a) as a constituent monomer becomes broad, and the fluidity of the semiconductor encapsulant composition containing this copolymer may decrease. b / w f is more preferably 0.80 or less, and even more preferably 0.60 or less.

[0028] The aforementioned w b / w f The chromatogram (vertical axis: refractive index intensity, horizontal axis: retention time) for calculating the above was obtained using an EcoSEC GPC calculation program, using a gel permeation chromatography (GPC) system equipped with a Tosoh Corporation HLC-8320GPC (registered trademark) guard column, a Resonaq Corporation Shodex (registered trademark) KF-G guard column, and three Resonaq Corporation Shodex (registered trademark) KF804L columns, with the column temperature set at 40°C and tetrahydrofuran used as the developing solvent at a flow rate of 1 mL / min, and with 0.1 mL of a 0.1 mass % tetrahydrofuran solution of polyalkylene glycol mono(meth)acrylate (monomer (a)) injected.

[0029] Monomer (a) satisfying the requirements of formula (Y) can be produced by adding an alkylene oxide having 2 to 4 carbon atoms to a starting material in the presence of a composite metal cyanide complex catalyst (hereinafter sometimes abbreviated as "DMC catalyst"). Specifically, the starting material and the DMC catalyst are placed in a reaction vessel, and the alkylene oxide having 2 to 4 carbon atoms is added continuously or intermittently under stirring in an inert gas atmosphere to cause addition polymerization. The alkylene oxide having 2 to 4 carbon atoms may be added under pressure or at atmospheric pressure. Examples of starting materials in this case include hydroxyalkyl (meth)acrylates, more specifically, 2-hydroxypropyl methacrylate. Examples of the alkylene oxide having 2 to 4 carbon atoms include one or more selected from ethylene oxide, propylene oxide, and butylene oxide.

[0030] There is no limitation on the average supply rate of the alkylene oxide having 2 to 4 carbon atoms that is added dropwise during addition polymerization, but it is desirable to change it depending on the amount of alkylene oxide charged. Specifically, when V1 is the rate (supply mass per unit time) during which 5% by mass or more and 20% by mass or less of the total amount of alkylene oxide having 2 to 4 carbon atoms is supplied dropwise, V2 is the rate during which more than 20% by mass and 50% by mass or less of the total amount of alkylene oxide having 2 to 4 carbon atoms is supplied dropwise, and V3 is the rate during which more than 50% by mass and 100% by mass or less of the total amount of alkylene oxide having 2 to 4 carbon atoms is supplied dropwise, in one embodiment for producing monomer (a), it is preferable to control the average supply rate of the alkylene oxide having 2 to 4 carbon atoms so that V1 / V2 = 1.1 to 2.0 and V2 / V3 = 1.1 to 1.5.

[0031] The reaction temperature for adding an alkylene oxide having 2 to 4 carbon atoms to the starting material is preferably 50 to 120° C., more preferably 60 to 90° C. If the reaction temperature is lower than 50° C., the reaction rate is very slow, and if it is higher than 120° C., problems such as polymerization of polymerizable groups in the starting material and coloration occur.

[0032] There are no particular restrictions on the amount of trace water contained in the starting materials and the alkylene oxide having 2 to 4 carbon atoms, but it is desirable that the amount of water contained in the starting materials be 0.5% by mass or less, and that the amount of water contained in the alkylene oxide having 2 to 4 carbon atoms be 0.01% by mass or less.

[0033] The amount of the DMC catalyst used is not particularly limited, but is preferably 0.0001 to 0.1 parts by mass, more preferably 0.001 to 0.05 parts by mass, per 100 parts by mass of the monomer (a) to be produced. The DMC catalyst may be added to the reaction system all at once at the beginning, or may be added in portions one after another. After the polymerization reaction is completed, the DMC catalyst is removed. The DMC catalyst can be removed by known methods such as filtration, centrifugation, or treatment with a synthetic adsorbent.

[0034] The content of monomer (a) as a constituent monomer in the copolymerization, i.e., the content of constituent units derived from monomer (a), may be 20 to 40 mass%, preferably 25 to 40 mass%, and more preferably 30 to 40 mass%, relative to 100 mass% of the total constituent monomers. By adjusting the content of constituent units derived from monomer (a) within the above range, the fluidity of the semiconductor encapsulant composition containing the copolymer can be improved and thermal expansion of the semiconductor encapsulant can be suppressed. The content of constituent units derived from monomer (a) can be calculated from the blending ratio of the monomers during production of the copolymer.

[0035] [Monomer (b)] The monomer (b) used in the embodiment of the present invention may be an alkyl ester monomer represented by the general formula (2), more specifically, a (meth)acrylic acid alkyl ester. When the copolymer according to the embodiment of the present invention contains such a monomer (b) as a constituent monomer, the thermal expansion of the semiconductor encapsulant obtained from the semiconductor encapsulant composition described below can be suppressed.

[0036] In formula (2), R 2 is a hydrogen atom or a methyl group, and is preferably a methyl group from the viewpoint of ease of polymerization.

[0037] In formula (2), R 3 is an alkyl group having 1 to 4 carbon atoms. Examples of such an alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, and a butyl group. From the viewpoint of suppressing the thermal expansion of the semiconductor encapsulant obtained from the semiconductor encapsulant composition described later, R 3 The alkyl group constituting R preferably has 1 to 3 carbon atoms, more preferably 1 to 2 carbon atoms. 3 The monomer (b) may be linear or branched, but is preferably linear. The monomer (b) may be used singly or in combination of two or more.

[0038] The content of monomer (b) as a constituent monomer in the copolymer, i.e., the content of constituent units derived from monomer (b), may be 10 to 50 mass%, preferably 15 to 45 mass%, and more preferably 20 to 40 mass%, relative to 100 mass% of the total constituent monomers. By adjusting the content of constituent units derived from monomer (b) within the above range, it is possible to improve the suppression of thermal expansion of a semiconductor encapsulant obtained from a semiconductor encapsulant composition containing the copolymer, and to improve the compatibility between monomer (a) and monomer (c). The content of constituent units derived from monomer (b) can be calculated from the blending ratio of the monomers during the production of the copolymer.

[0039] [Monomer (c)] The monomer (c) used in the embodiment of the present invention may be any monomer having a maleimide skeleton. When the copolymer according to the embodiment of the present invention contains such a monomer (c) as a constituent monomer, it is possible to improve the suppression of thermal expansion of the semiconductor encapsulant obtained from the semiconductor encapsulant composition described below.

[0040] Examples of monomers having a maleimide skeleton include N-alkylmaleimides such as N-methylmaleimide, N-butylmaleimide, and N-cyclohexylmaleimide; and N-arylmaleimides such as N-phenylmaleimide, N-chlorophenylmaleimide, N-methylphenylmaleimide, N-methoxyphenylmaleimide, and N-tribromophenylmaleimide. Monomer (c) may be used alone or in combination of two or more. Among these, N-alkylmaleimides and N-phenylmaleimide are particularly preferred from the viewpoints of improving the suppression of thermal expansion of the semiconductor encapsulant composition and compatibility with epoxy resins.

[0041] The content of monomer (c) as a constituent monomer in the copolymer, i.e., the content of constituent units derived from monomer (c), may be 30 to 50 mass%, preferably 35 to 50 mass%, and more preferably 40 to 50 mass%, relative to 100 mass% of the total constituent monomers. By adjusting the content of constituent units derived from monomer (c) within the above range, it is possible to improve the suppression of thermal expansion of a semiconductor encapsulant obtained from a semiconductor encapsulant composition containing the copolymer. The content of constituent units derived from monomer (c) can be calculated from the blending ratio of the monomers during the production of the copolymer.

[0042] [Other copolymerizable monomers (monomer (d))] The copolymer according to the embodiment of the present invention may contain, as a constituent monomer, a monomer (d) in addition to the monomers (a) to (c). The monomer (d) may be any monomer copolymerizable with the monomers (a) to (c), and may be, for example, a vinyl compound other than the monomers (a) to (c). Examples of such vinyl compounds include styrene-based monomers such as styrene, vinyltoluene, and α-methylstyrene; fluorine-containing vinyl monomers such as perfluoroethylene, perfluoropropylene, and vinylidene fluoride; chlorine-containing vinyl monomers such as vinyl chloride, vinylidene chloride, and allyl chloride; styrene-based monomers such as styrene, vinyltoluene, and α-methylstyrene; fluorine-containing vinyl monomers such as perfluoroethylene, perfluoropropylene, and vinylidene fluoride; chlorine-containing vinyl monomers such as vinyl chloride, vinylidene chloride, and allyl chloride; cyano-containing vinyl monomers such as (meth)acrylonitrile; carbamoyl-containing vinyl monomers such as (meth)acrylamide; and vinyl esters such as vinyl acetate and vinyl benzoate.

[0043] The content of monomer (d) as a constituent monomer in the copolymer, i.e., the content of the constituent units derived from monomer (d), may be 0 to 40 parts by mass per 100 parts by mass of the total of the constituent monomers. When monomer (d) is included as a constituent monomer, i.e., when the content of its constituent units is greater than 0 parts, the content of monomer (d) may be within a range that allows its function to be exhibited, and can be appropriately determined depending on the types of monomers (a) to (d). The content of the constituent units derived from monomer (d) can be calculated from the blending ratio of the monomers during the production of the copolymer.

[0044] [Weight average molecular weight of copolymer (Mw)] The weight-average molecular weight of the copolymer is 1,000 to 100,000, preferably 3,000 to 50,000, more preferably 5,000 to 30,000, and even more preferably 6,000 to 25,000. If the weight-average molecular weight of the polymer is lower than 1,000, low thermal expansion and water resistance may be insufficient, while if the weight-average molecular weight is higher than 100,000, the viscosity may increase, resulting in poor flowability. The weight-average molecular weight of the copolymer can be determined in polystyrene equivalent terms using gel permeation chromatography (GPC).

[0045] [Method of producing copolymer] The copolymer according to the embodiment of the present invention can be produced, for example, by radically polymerizing the above-mentioned monomers in the presence of a polymerization initiator. Examples of the polymerization method include solution polymerization, suspension polymerization, emulsion polymerization, etc. Among these, solution polymerization is preferred because it is easy to adjust the weight-average molecular weight of the copolymer to fall within the above-mentioned preferred range.

[0046] Known polymerization initiators can be used. Examples of the polymerization initiator include organic peroxides and azo compounds. The polymerization initiators may be used alone or in combination of two or more.

[0047] Examples of organic peroxides include cumyl peroxyneodecanoate, tert-butyl peroxyneodecanoate, tert-hexyl peroxypivalate, methyl ethyl ketone peroxide, 2,5-dimethylhexane-2,5-dihydroperoxide, tert-butylcumyl peroxide, dicumyl peroxide, and α,α'-bis(tert-butylperoxy-m-isopropyl)benzene.

[0048] Examples of azo compounds include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 2-(carbamoylazo)isobutyronitrile, 2-phenylazo-4-methoxy-2,4-dimethyl-valeronitrile, 2,2'-azobis(2-methyl-N-phenylpropionamidine) dihydrochloride, 2,2,2'-azobis[2-(2-imidazolin-2-yl)propane], 2,2'-azobis(2-methylpropionamide) dihydrate, and 2,2'-azobis(2,4,4-trimethylpentane).

[0049] From the viewpoint of compatibility with the epoxy resin contained in the semiconductor encapsulant composition described below, it is preferable to use a polymerization initiator containing a cyclic structure, and more preferable are those containing a benzene ring such as cumyl peroxy neodecanoate, tert-butylcumyl peroxide, dicumyl peroxide, and α,α'-bis(tert-butylperoxy-m-isopropyl)benzene.

[0050] The amount of polymerization initiator used can be appropriately set depending on the combination of monomers used, reaction conditions, etc. The method for adding the polymerization initiator and monomers to the reactor is not particularly limited. For example, the entire amount of the polymerization initiator and monomers may be added to the reactor all at once, or the polymerization initiator and monomers may be added to the reactor in portions (for example, dropwise).

[0051] The solvent used in the solution polymerization is not particularly limited as long as it can dissolve the monomer and the polymerization initiator. Examples of the solvent include 1-propanol, methyl ethyl ketone, and propylene glycol monomethyl ether.

[0052] When solution polymerization is carried out, the total concentration of each monomer in the solution is preferably 10 to 60% by mass, more preferably 20 to 50% by mass. If the total concentration is too low, the monomers tend to remain after polymerization, which may result in a decrease in the weight-average molecular weight of the resulting copolymer. If the total concentration is too high, the monomers may be difficult to dissolve in the solvent, and heat generation during polymerization may become difficult to control.

[0053] The polymerization temperature can be appropriately set depending on the type of monomer, type of polymerization initiator, type of solvent, etc. The polymerization temperature is, for example, 50°C to 120°C. The polymerization time can be appropriately set depending on the type of polymerization initiator, polymerization temperature, etc. For example, when cumyl peroxy neodecanoate is used as the polymerization initiator and the polymerization temperature is 70°C, the polymerization time is, for example, about 5 hours. The polymerization time can also be appropriately adjusted depending on the manner in which raw materials such as monomer and polymerization initiator are charged. For example, when the monomer and polymerization initiator are added dropwise to the reactor, they can be added dropwise in small amounts over a certain period of time, and after the entire amount has been added, the reaction can be continued so as to minimize the amount of raw materials remaining. For example, when the polymerization time is 5 hours, the dropwise addition time can be 1 to 3 hours, and the subsequent reaction can be continued for 2 to 4 hours.

[0054] The copolymer solution obtained by solution polymerization is vacuum dried to remove the solvent, thereby isolating the copolymer, which can be used in the production of a semiconductor encapsulant composition as described below.

[0055] [Semiconductor encapsulation modifier] The semiconductor encapsulating modifier according to an embodiment of the present invention is composed of the copolymer described above. That is, the semiconductor encapsulating modifier may be composed solely of the copolymer, or may contain the copolymer as an active ingredient and other ingredients. Examples of other ingredients include solvents and colorants. The semiconductor encapsulating modifier is preferably composed solely of the copolymer. The copolymer may be used alone or in combination of two or more kinds.

[0056] [Semiconductor encapsulant composition] The semiconductor encapsulant composition according to an embodiment of the present invention contains the semiconductor encapsulant modifier, an epoxy resin, a curing agent, and a filler. The semiconductor encapsulant modifier contains the copolymer, and therefore the semiconductor encapsulant composition contains the copolymer by including the semiconductor encapsulant modifier. Components contained in the semiconductor encapsulant composition, such as the semiconductor encapsulant modifier, epoxy resin, curing agent, and filler, will be described below.

[0057] [Semiconductor encapsulation modifier] The semiconductor encapsulation modifier used in the semiconductor encapsulation composition according to the embodiment of the present invention is as described above. From the viewpoint of molding stability of the semiconductor encapsulation composition, the content of the semiconductor encapsulation modifier is preferably 0.1 to 5 parts by mass, more preferably 0.3 to 3 parts by mass, and even more preferably 0.5 to 2.5 parts by mass, as a polymer, relative to 100 parts by mass of the semiconductor encapsulation composition.

[0058] [Epoxy resin] As the epoxy resin used in the semiconductor encapsulant composition according to the embodiment of the present invention, any monomer, oligomer, or polymer having two or more epoxy groups in one molecule can be used, and the molecular weight and molecular structure thereof are not limited.

[0059] Examples of epoxy resins include: Biphenyl type epoxy resin, Bisphenol-type epoxy resins such as bisphenol A-type epoxy resin, bisphenol F-type epoxy resin, and tetramethylbisphenol F-type epoxy resin, polyfunctional epoxy resins such as stilbene-type epoxy resins, novolac-type epoxy resins such as phenol novolac-type epoxy resins and cresol novolac-type epoxy resins, trisphenol-type epoxy resins exemplified by triphenolmethane-type epoxy resins and alkyl-modified triphenolmethane-type epoxy resins, etc. phenol aralkyl type epoxy resins such as phenol aralkyl type epoxy resins having a phenylene skeleton, naphthol aralkyl type epoxy resins having a phenylene skeleton, phenol aralkyl type epoxy resins having a biphenylene skeleton, and naphthol aralkyl type epoxy resins having a biphenylene skeleton; naphthol-type epoxy resins such as dihydroxynaphthalene-type epoxy resins and epoxy resins obtained by glycidyl etherifying dihydroxynaphthalene dimers; Triazine nucleus-containing epoxy resins such as triglycidyl isocyanurate and monoallyl diglycidyl isocyanurate; Examples include bridged cyclic hydrocarbon compound-modified phenolic epoxy resins such as dicyclopentadiene-modified phenolic epoxy resins. These may be used alone or in combination of two or more.

[0060] Among these, it is preferable to include one or more types selected from biphenyl-type epoxy resins, bisphenol-type epoxy resins, polyfunctional epoxy resins, and phenol aralkyl-type epoxy resins, and it is more preferable to include biphenyl-type epoxy resins and phenol aralkyl-type epoxy resins.

[0061] From the viewpoint of molding stability of the semiconductor encapsulant composition, the content of the epoxy resin is preferably 1 to 15 parts by mass, more preferably 3 to 13 parts by mass, and even more preferably 5 to 10 parts by mass per 100 parts by mass of the semiconductor encapsulant composition.

[0062] [Hardening agent] The curing agent used in the semiconductor encapsulant composition according to the embodiment of the present invention is not particularly limited, and a curing agent generally used as an epoxy resin curing agent can be used, and examples thereof include amine-based, acid anhydride-based, and phenol-based curing agents.

[0063] Specific examples of amine-based curing agents include aliphatic polyamines such as diethylenetriamine (DETA), triethylenetetramine (TETA), and metaxylylenediamine (MXDA); aromatic polyamines such as diaminodiphenylmethane (DDM) and m-phenylenediamine (MPDA); and polyamine compounds such as dicyandiamide (DICY) and organic acid dihydralazide.

[0064] Examples of acid anhydride curing agents include alicyclic acid anhydrides such as hexahydrophthalic anhydride (HHPA) and methyltetrahydrophthalic anhydride (MTHPA), and aromatic acid anhydrides such as trimellitic anhydride (TMA) and benzophenonetetracarboxylic acid (BTDA).

[0065] Examples of phenol-based curing agents include novolac-type phenolic resins such as phenol novolac resin and cresol novolac resin; polyfunctional phenolic resins such as phenolic resins having a triphenylmethane skeleton; modified phenolic resins such as terpene-modified phenolic resin and dicyclopentadiene-modified phenolic resin; phenol aralkyl-type phenolic resins such as phenol aralkyl resins having a phenylene skeleton and / or biphenylene skeleton and naphthol aralkyl resins having a phenylene and / or biphenylene skeleton; and the like.

[0066] In addition to the above curing agents, for example, polymercaptan compounds such as thioesters and thioethers, isocyanate compounds such as isocyanate prepolymers and blocked isocyanates, and organic acids such as carboxylic acid-containing polyester resins can also be used.

[0067] These curing agents may be used alone or in combination of two or more.

[0068] From the viewpoint of molding stability of the semiconductor encapsulant composition, the content of the curing agent is preferably 1 to 15 parts by mass, more preferably 3 to 13 parts by mass, and even more preferably 5 to 10 parts by mass, per 100 parts by mass of the semiconductor encapsulant composition.

[0069] [Filler] As the filler used in the semiconductor encapsulant composition according to the embodiment of the present invention, those used in semiconductor encapsulants can be applied. Specific examples include inorganic fillers and organic fillers. Of the above specific examples, the filler preferably includes an inorganic filler.

[0070] Specific examples of inorganic fillers include silica such as synthetic spherical silica, fused crushed silica, fused spherical silica, crystalline silica, secondary agglomerated silica, and finely divided silica, alumina, silicon nitride, aluminum nitride, boron nitride, titanium oxide, silicon carbide, metal compounds such as aluminum hydroxide, magnesium hydroxide, and titanium white, talc, clay, mica, and glass fiber. Among the specific examples, it is preferable to use silica such as synthetic spherical silica, fused crushed silica, fused spherical silica, crystalline silica, secondary agglomerated silica, and finely divided silica, and it is more preferable to use synthetic spherical silica or fused spherical silica. The inorganic fillers may be used alone or in combination of two or more.

[0071] Specific examples of the organic filler include organosilicone powder, polyethylene powder, etc. One type of organic filler may be used alone, or two or more types may be used in combination.

[0072] From the viewpoint of improving thermal expansion properties and fluidity, the content of the filler is preferably 63 to 97 parts by mass, more preferably 70 to 93 parts by mass, and even more preferably 77 to 89 parts by mass per 100 parts by mass of the semiconductor encapsulant composition.

[0073] [Other ingredients] (curing accelerator) The semiconductor encapsulant composition according to the embodiment of the present invention may contain a curing accelerator. The curing accelerator that can be used is not limited as long as it accelerates the curing reaction of the epoxy resin and the curing agent, and can be selected depending on the type of the epoxy resin and the curing agent. Specific examples of such curing accelerators include organic phosphines such as triphenylphosphine, tetra-substituted phosphonium compounds, phosphobetaine compounds, adducts of phosphine compounds and quinone compounds, and phosphorus atom-containing compounds such as adducts of phosphonium compounds and silane compounds; Examples include imidazole compounds such as 2-methylimidazole, 2-ethyl-4-methylimidazole (EMI24), 2-phenylimidazole (2PZ), and 1-benzyl-2-phenylimidazole (1B2PZ), as well as amidines and tertiary amines such as 1,8-diazabicyclo[5.4.0]undecene-7 and benzyldimethylamine. The curing accelerator may be used alone or in combination of two or more.

[0074] From the viewpoint of molding stability of the semiconductor encapsulant composition, the content of the curing accelerator is preferably 0 to 2 parts by mass, more preferably 0.1 to 1 part by mass, and even more preferably 0.1 to 0.5 parts by mass, relative to 100 parts by mass of the semiconductor encapsulant composition.

[0075] (Other ingredients) The semiconductor encapsulant composition according to the embodiment of the present invention may further contain components other than the copolymer, epoxy resin, curing agent, filler, and curing accelerator described above, within the scope of not impairing the effects of the present invention. Such other components may be used singly or in combination of two or more.

[0076] Examples of such other components include coupling agents, heat resistance improvers, mold release agents, flame retardants, solvents, colorants, neutralizers, etc. The total content of the other components is preferably 0 to 10% by mass, more preferably 0 to 7% by mass, and even more preferably 0 to 5% by mass, based on the entire semiconductor encapsulant composition.

[0077] [Method of manufacturing semiconductor encapsulant composition] The semiconductor encapsulant composition according to an embodiment of the present invention can be produced by mixing the semiconductor encapsulation modifier (copolymer), epoxy resin, curing agent, and filler, as well as other components as needed. The method for mixing the components is not particularly limited; all components may be mixed simultaneously, or each component may be added sequentially and mixed. From the viewpoint of uniform mixing, a method in which a mixture of the semiconductor encapsulation modifier (copolymer), epoxy resin, curing agent, and other optional components is melt-kneaded, and then the filler is added and kneaded uniformly is preferred. It is more preferred to add the filler in multiple batches and knead. The conditions for mixing and kneading can be appropriately set according to standard methods, taking into account the types and blending ratios of the various components.

[0078] The semiconductor encapsulant composition according to the embodiment of the present invention can be molded and cured using a molding machine used in the technical field to function as a semiconductor encapsulant. A semiconductor encapsulant composition containing the above-mentioned copolymer as a semiconductor encapsulation modifier has excellent fluidity when heated and good moldability, and the semiconductor encapsulant obtained as a cured product has low thermal expansion sufficient to accommodate miniaturization and thinning, and also has good water resistance. Thus, the semiconductor encapsulant composition can satisfactorily achieve both fluidity, low thermal expansion, and water resistance. These properties can be evaluated, for example, by the method described in the Examples section below. [Example]

[0079] Hereinafter, the embodiments of the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0080] The monomers used in the synthesis of copolymers X1 to X13, which will be described later, are shown below. <Monomer (a)> Polypropylene glycol methacrylate obtained in Synthesis Example 2 described below <Monomer (b)> Methyl methacrylate: Acryester M, manufactured by Mitsubishi Chemical Corporation <Monomer (c)> N-Cyclohexylmaleimide: Imilex-C, manufactured by Nippon Shokubai Co., Ltd. N-phenylmaleimide: Imilex-P, manufactured by Nippon Shokubai Co., Ltd.

[0081] [Synthesis Example 1] (Synthesis of double metal cyanide complex (DMC) catalyst) To 2.0 mL of an aqueous solution containing 2.1 g of zinc chloride, 15 mL of an aqueous solution containing 0.84 g of potassium hexacyanocobaltate (K3Co(CN)6) was added dropwise over 15 minutes while stirring at 40 °C. After the addition was complete, 16 mL of water and 16 g of tert-butyl alcohol were added, the temperature was raised to 70 °C, and the mixture was stirred for 1 hour. After cooling to room temperature, a first filtration operation was performed to obtain a solid. To this solid, 14 mL of water and 8.0 g of tert-butyl alcohol were added, and the mixture was stirred for 30 minutes. A second filtration operation was performed to obtain a solid. To the resulting solid, 18.6 g of tert-butyl alcohol and 1.2 g of methanol were added, and the mixture was stirred for 30 minutes. After that, the mixture was filtered (for the third time). The resulting solid was dried at 40°C under reduced pressure for 3 hours to obtain 0.7 g of DMC catalyst (Zn(II)3[Co(III)(CN)6]2(H2O)4(tert-butyl alcohol)2).

[0082] [Synthesis Example 2] (Synthesis of Monomer (a)) A 5-liter (4,890 mL) stainless steel pressure reactor equipped with a thermometer, pressure gauge, safety valve, nitrogen gas inlet, stirrer, vacuum exhaust, cooling coil, and steam jacket was charged with 300 g of 2-hydroxypropyl methacrylate (HPMA) (water content: 0.02% by mass), 0.2 g of the DMC catalyst obtained in Synthesis Example 1, and 0.7 g of 2,6-di-tert-butylhydroxytoluene (BHT). After nitrogen purge, the temperature was raised to 70°C, and 182 g of propylene oxide (methyl oxirane, water content: 0.005% by mass) was added dropwise through the nitrogen gas inlet with stirring at a pressure of 0.3 MPa or less. The pressure and temperature in the reactor were monitored over time, and the pressure in the reactor rapidly decreased 5 hours after the end of the dropwise addition. Thereafter, while maintaining the temperature inside the reaction vessel at 70°C, 1752 g of propylene oxide was gradually added dropwise from the nitrogen gas inlet tube under conditions of 0.5 MPa or less. The average supply rates were V1 260 g / h, V2 203 g / h, and V3 152 g / h (V1 / V2 = 1.28, V2 / V3 = 1.34). After the completion of the dropwise addition, the reaction mixture was allowed to react for another 0.5 hours at 70°C, and then the reaction mixture was extracted from the reaction layer and filtered to remove solids, yielding liquid monomer (a). The obtained monomer (a) was subjected to GPC measurement using the aforementioned HLC-8320GPC (registered trademark). Monomer (a) was a monomer having R 1 is a methyl group, AO is an oxypropylene group, and n is 17. The w calculated from the chromatograph obtained by GPC measurement b / w f The viscosity was 0.46 and the molecular weight was 1070. The molecular weight was calculated from the hydroxyl value measured in accordance with JIS K-1557-1.

[0083] [Example 1] (Synthesis of Copolymer X1) A 1-L separable flask equipped with a stirrer, thermometer, condenser, dropping funnel, and nitrogen gas inlet tube was charged with 150 g of propylene glycol monomethyl ether as a solvent, and the atmosphere inside the flask was replaced with nitrogen to create a nitrogen atmosphere. A monomer solution was prepared by dissolving 38 g of the monomer (a) obtained in Synthesis Example 2, 50 g of methyl methacrylate, and 38 g of N-cyclohexylmaleimide in 119 g of propylene glycol monomethyl ether, and a polymerization initiator solution was prepared containing 25 g of propylene glycol monomethyl ether as a solvent and 25 g of cumyl peroxyneodecanoate (Percumyl ND, manufactured by NOF Corporation) as a polymerization initiator. The temperature inside the reaction vessel was raised to 70°C, and the monomer solution and the polymerization initiator solution were simultaneously dropped into a 1 L separable flask over 2 hours, respectively. Thereafter, the reaction mixture was reacted at 70°C for 3 hours to obtain a propylene glycol monomethyl ether solution of copolymer X1. The propylene glycol monomethyl ether solution of copolymer X1 was heated to 80±10°C and dried under reduced pressure at a vacuum of 100±50 torr (13.3±6.7 kPa) to remove the solvent, thereby isolating copolymer X1. The weight-average molecular weight of the obtained copolymer X1 was measured by the method described below.

[0084] [Examples 2 to 8, Comparative Examples 1 to 3 and 5] (Synthesis of Copolymer X2 to Copolymer X11 and X13) Copolymers X2 to X11 and X13 were obtained in the same manner as in Example 1, except that the blending ratios of monomers (a) to (c) were as shown in Tables 1 and 2. The weight-average molecular weights of the obtained copolymers X2 to X11 and X13 were measured by the method described below. The measurement results are shown in Tables 1 and 2.

[0085] Comparative Example 4 (Synthesis of copolymer X12) Copolymer X12 was obtained in the same manner as in Example 1, except that the blending ratios of monomers (a) to (c) were as shown in Table 2 and the amount of cumyl peroxyneodecanoate (Percumyl ND, manufactured by NOF Corporation) was changed to 1.3 g.

[0086] [Measurement of weight-average molecular weight] The weight average molecular weight of each of the polymers X1 to X13 was determined using gel permeation chromatography (GPC) under the following conditions. Equipment: Tosoh Corporation, HLC-8220 Column: Shodex LF-804, manufactured by Resonac Co., Ltd. Standard material: polystyrene Eluent: THF (tetrahydrofuran) Flow rate: 1.0ml / min Column temperature: 40℃ Detector: RID (refractive index detector)

[0087] [Table 1]

[0088] [Table 2]

[0089] [Example 9] (Preparation of semiconductor encapsulant composition A1) 0.63 g of the copolymer X1 obtained in Example 1 as a semiconductor encapsulation modifier, 3.14 g of a biphenyl-type epoxy resin (YX4000H, manufactured by Mitsubishi Chemical Corporation) as an epoxy resin, 3.14 g of a phenol novolac-type phenolic resin (PR-55617, manufactured by Sumitomo Bakelite Co., Ltd.) as a curing agent, and 0.095 g of triphenylphosphine (Tokyo Chemical Industry Co., Ltd.) as a curing accelerator were kneaded in a mortar, placed in a stainless steel tray, melted on a hot plate heated to 110 ° C, and uniformly mixed with a spatula. Approximately 1 / 4 of 43.0 g of silica (Denka Fused Silica FB-15D, manufactured by Denka Co., Ltd.) was added to the resulting melt and uniformly mixed with a spatula. This silica addition operation was repeated about four times to obtain a semiconductor encapsulation composition A1 in which all silica and other components were uniformly mixed.

[0090] [Examples 10 to 18, Comparative Examples 6 to 11] (Preparation of Semiconductor Encapsulant Compositions A2 to A16) Semiconductor encapsulant compositions A2 to A16 were prepared in the same manner as in Example 9, except that the blending ratios of each component were as shown in Tables 3 and 4 (the blending ratios in the tables are in "mass %").

[0091] [Rating 1] (Liquidity assessment) The fluidity of semiconductor encapsulant compositions A1 to A16 is influenced by the resin mixture of the component composition excluding the curing accelerator and silica from the component compositions of semiconductor encapsulant compositions A1 to A16 shown in Tables 3 and 4. Therefore, the fluidity of semiconductor encapsulant compositions A1 to A22 when heated was evaluated using the resin mixture. The fluidity was also evaluated by measuring the shear viscosity of the resin mixture.

[0092] (Production Example 1) <Preparation of Resin Mixture A1 Constituting Semiconductor Encapsulant Composition A1> 0.63 g of copolymer X1, 3.14 g of biphenyl-type epoxy resin (YX4000H, manufactured by Mitsubishi Chemical Corporation), and 3.14 g of phenol novolac-type phenolic resin (PR-55617, manufactured by Sumitomo Bakelite Co., Ltd.) were weighed out and kneaded in a mortar to obtain resin mixture A1. That is, the blending ratio of copolymer, epoxy resin, and curing agent in resin mixture A1 was the same as that in the semiconductor encapsulant composition A1 shown in Table 3.

[0093] (Examples 2 to 16) <Preparation of Resin Mixtures A2 to A16 Constituting Semiconductor Encapsulant Compositions A2 to A16> Resin mixtures A2 to A16 were obtained in the same manner as in Preparation Example 1, except that the curing accelerator and filler were not included and the other components were mixed in the proportions shown in Tables 3 and 4.

[0094] (shear viscosity measurement) The shear viscosity (mPa·s) at 100°C of resin mixtures A1 to A16 obtained as described above was measured using a rheometer (MCR302, manufactured by Anton Paar Japan Co., Ltd.). Shear viscosity measurements were performed using a cone-plate (D-CP / PP7, manufactured by Anton Paar Japan Co., Ltd.) with the rotation speed varying from 0.1 / s to 300 / s over 1 minute, followed by measurement at 300 / s for approximately 7 minutes. The value at which the shear viscosity became constant was recorded as the measured value. Fluidity was evaluated as follows: a shear viscosity of 14 mPa·s or less was rated as ◎, a shear viscosity of more than 14 mPa·s but less than 23 mPa·s was rated as 〇, and a shear viscosity of 23 mPa·s or more was rated as ×.

[0095] [Rating 2] The semiconductor encapsulation compositions A1 to A16 obtained in Examples 9 to 16 and Comparative Examples 6 to 11 were evaluated for thermal expansion and water resistance by the following methods.

[0096] (Evaluation of thermal expansion) The semiconductor encapsulant compositions A1 to A16 obtained as described above were heated on a hot plate heated to 110°C, spread on an aluminum pan heat-resistant to 400°C or higher, and a flat plate was pressed against the top surface of each composition to form a flat surface. The resulting pan was then cooled to room temperature to obtain semiconductor encapsulant test pieces. The flat surface of the test piece thus obtained was heated from 30°C to 320°C (10°C / min) using a thermomechanical analyzer (Seiko Instruments Inc., EXSTAR6000), and the thermal expansion of each test piece was measured. The magnitude of the slope of the temperature-TMA line (hereinafter simply referred to as the "TMA line") obtained under the heating conditions was used as an index of thermal expandability. Each semiconductor encapsulant composition prepared without the copolymer was used as a blank, and the value calculated so that the slope of the blank TMA line was 100 was used as an evaluation value of thermal expandability. The thermal expansion property was evaluated as follows: a rating of 105 or less was rated as excellent; a rating of more than 105 but less than 120 was rated as good; and a rating of 120 or more was rated as poor.

[0097] (Water resistance evaluation) The semiconductor encapsulant compositions A1 to A18 obtained as described above were heated on a hot plate heated to 110°C and filled into a mold with a cavity of 3 cm x 3 cm x 0.5 cm (length x width x thickness) that had also been heated to 110°C. After 180 minutes, the mold was cooled and removed to obtain test pieces for the semiconductor encapsulant. The test pieces and 20 g of water were placed in a 50 ml screw-cap test tube and shaken continuously for 6 hours in an 80°C water bath. After that, water droplets adhering to the test pieces were wiped off, and the breakage rate and mass change of the test pieces were determined. The breakage rate (%) was calculated by measuring the dimensions of the test pieces that fell off during the test, calculating the breakage area, and then using the area (total area) measured before the test using the following formula: [Damage rate (%)] = [Damage area (cm 2 )] / [Total area (cm 2 )] x 100 The mass change was calculated using the following formula. [Mass change (%)] = [Weight after test (g)] / [Weight before test (g)] x 100 The damage rate was evaluated as follows: 10% or less: ◎, 10% to less than 20%: 〇, 20% or more: ×. The mass change was evaluated as 〇: less than 2.0%, and ×: 2.0% or more.

[0098] The above results are shown in Tables 3 and 4. In the evaluation results shown in Tables 3 and 4, the values ​​in parentheses are the measured values ​​for each evaluation.

[0099] [Table 3]

[0100] [Table 4]

[0101] As shown in Table 3, the semiconductor encapsulant compositions A1 to A10 of Examples 9 to 18 containing the copolymers X1 to X8 of Examples 1 to 8 have good fluidity, and the semiconductor encapsulants obtained using these compositions A1 to A10 have low thermal expansion and excellent water resistance. Thus, it is clear that the inclusion of a specific copolymer can prevent the semiconductor encapsulant composition from deteriorating in fluidity during molding, and can also suppress the thermal expansion of the semiconductor encapsulant, thereby imparting good water resistance to the semiconductor encapsulant. On the other hand, the semiconductor encapsulant composition A11 of Comparative Example 6, which did not contain the specific copolymer, was evaluated as having poor water resistance and was unable to achieve high fluidity, low thermal expansion, and high water resistance all at the same time. In the semiconductor encapsulation material compositions A12 to A16 of Comparative Examples 7 to 11, since the specific copolymer was not contained, it was not possible to achieve a balance between thermal expansion property, fluidity, and water resistance.

Claims

1. The composition contains, as constituent monomers, 20 to 40% by mass of a polyalkylene glycol monomer (a) represented by the following general formula (1), 10 to 50% by mass of an alkyl ester monomer (b) represented by the following general formula (2), and 30 to 50% by mass of a monomer (c) having a maleimide skeleton, A copolymer having a weight average molecular weight of 1,000 to 100,000. General formula (1): CH ２ =CR １ -COO-(AO) ｎ -H ・・・(1) (In formula (1), R １ represents a hydrogen atom or a methyl group, AO represents at least one oxyalkylene group having 2 to 4 carbon atoms, and n represents the average number of moles of oxyalkylene groups added, which is a number from 5 to 100. General formula (2): CH ２ =CR ２ -COO-R ３ ・・・(2) (In formula (2), R ２ represents a hydrogen atom or a methyl group, and R ３ represents an alkyl group having 1 to 4 carbon atoms.)

2. A modifier for semiconductor encapsulation, comprising the copolymer according to claim 1.

3. A semiconductor encapsulant composition containing the semiconductor encapsulation modifier according to claim 2, A semiconductor encapsulant composition comprising 0.1 to 5 mass% of the semiconductor encapsulation modifier according to claim 2, 1 to 15 mass% of an epoxy resin, 1 to 15 mass% of a curing agent, and 63 to 97 mass% of a filler, when the entire semiconductor encapsulant composition is taken as 100 mass%.

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