Heat curable composition

Abstract

Provided is a heat curable composition comprising a component (A) and a component (B), said heat curable composition having a thixotropic index (the viscosity at a shear rate of 1s-1 divided by the viscosity at a shear rate of 103s-1) of not less than 1.1. The component (A) is a silane compound polymer having a repeating unit [repeating unit (1)] represented by formula (a-1) (where R1 is represents a C6-20 aryl group that is unsubstituted or that has a substituent). The component (B) is one or more fillers selected from the group consisting of alumina, aluminum nitride, and zinc oxide.

Description

thermosetting composition

[0001] This invention relates to a thermosetting composition.

[0002] Conventionally, SiO2 has been used as an insulating film for semiconductor devices, etc., by vacuum processes such as thermal CVD. ２ Film formation has been carried out. However, since vacuum processes are not suitable for forming insulating films that fill deep depressions, the SOG (Spin-on-Glass) method has attracted attention in recent years.

[0003] In the SOG method, an insulating film is typically formed by applying an insulating film forming solution by spin coating and curing the resulting coating. For example, Patent Document 1 describes a silicon oxide film forming composition containing a solvent, a silicon oxide forming compound dissolved and / or dispersed in the solvent, and silicon particles dispersed in the solvent, as well as a method for forming a silicon oxide film using this composition.

[0004] Japanese Patent Publication No. 2015-18952

[0005] Patent Document 1 describes that a relatively thick silicon oxide film can be formed in a short time using the SOG method, and that a silicon oxide film that is less prone to cracking can be formed by using the composition described in Patent Document 1. Therefore, it is considered that the silicon oxide film forming composition described in Patent Document 1 can be used as a material for forming a thick insulating film (for example, an insulating film with a thickness of several μm) in three-dimensional semiconductor devices such as three-dimensional NAND flash memory. However, when using a composition containing silicon particles, it is necessary to change the silicon particles into silicon oxide, which requires heat treatment under harsh conditions (900°C for 30 minutes in the example). Therefore, there has been a need for a more efficient method for forming a thick insulating film.

[0006] Also, in order to suppress failures and the like in semiconductor devices, it is preferable that the insulating film has excellent thermal conductivity. For this reason, it is conceivable to add a thermally conductive filler to the insulating film-forming composition. However, when using an insulating film-forming composition in which the filler is likely to settle, the composition of the insulating film obtained at the initial stage of the coating operation may be significantly different from the composition of the insulating film obtained at the final stage of the coating operation, and it was difficult to mass-produce an insulating film of a certain quality. The present invention has been made under such circumstances, and an object thereof is to provide a thermosetting composition capable of mass-producing a cured film of a certain quality.

[0007] The present inventors intensively studied a thermosetting composition containing a silane compound polymer in order to solve the above problems. As a result, they found that a cured film of a certain quality can be mass-produced by increasing the thixotropic index of the thermosetting composition, and thus completed the present invention.

[0008] Thus, according to the present invention, the thermosetting compositions of the following [1] to

[14] are provided. [1] A thermosetting composition containing the following component (A) and component (B), having a thixotropic index (viscosity when the shear rate is 1 s －１ / viscosity when the shear rate is 103 s －１ ) of 1.1 or more. Component (A): A silane compound polymer having a repeating unit [repeating unit (1)] represented by the following formula (a-1)

[0009]

[0010] [R １ represents an unsubstituted or substituted aryl group having 6 to 20 carbon atoms. ] Component (B): One or more fillers selected from the group consisting of alumina, aluminum nitride, and zinc oxide [2] The component (A) is the repeating unit (1) and the following formula (a-2)

[0011]

[0012] [R ２represents an alkyl group having 1 to 16 carbon atoms with or without substituents. A silane compound polymer having a repeating unit represented by [repeating unit (2)] and the repeating unit (1) as defined in [1]. The thermosetting composition according to [2], wherein the amount of the repeating unit (1) is 20 to 80 mol% based on the total amount of the repeating unit (1) and the repeating unit (2). The thermosetting composition according to [2] or [3], wherein the total amount of the repeating unit (1) and the repeating unit (2) is 70 to 100 mol% based on the total amount of the repeating units of the silane compound polymer. The component (A) is represented by the following formula (a-3)

[0013] <000,0095>a repeating unit represented by [repeating unit (3)], the repeating unit (1), and the following formula (a-4)

[0015]

[0016] 〔R ３ 、R ４Each of these independently represents an unsubstituted or substituted C1-C16 alkyl group, or an unsubstituted or substituted C6-C20 aryl group. The thermosetting composition according to [1] is a silane compound polymer having a repeating unit [repeating unit (4)] represented by ]. [6] The thermosetting composition according to [5], wherein the amount of repeating unit (3) is 20-50 mol%, the amount of repeating unit (1) is 30-78 mol%, and the amount of repeating unit (4) is 2-40 mol% of the total amount of repeating unit (3), repeating unit (1), and repeating unit (4). [7] The thermosetting composition according to [5] or [6], wherein the total amount of repeating unit (3), repeating unit (1), and repeating unit (4) is 50-100 mol% of the total repeating units of the silane compound polymer. [8] A thermosetting composition according to any one of [1] to [7], wherein the mass-average molecular weight (Mw) of component (A) is 1,000 to 10,000. [9] A thermosetting composition according to any one of [1] to [8], wherein component (A) is thermosetting.

[10] A thermosetting composition according to any one of [1] to [9], wherein the content of component (A) is 5 to 50% by mass of the total amount of components constituting the thermosetting composition (excluding the solvent).

[11] A thermosetting composition according to any one of [1] to

[10] , wherein the content of aluminum nitride is 50% by volume or more of the total amount of components constituting the thermosetting composition (excluding the solvent).

[12] A thermosetting composition according to any one of [1] to

[11] , wherein the content of component (B) is 100 to 1,000 parts by mass per 100 parts by mass of component (A).

[13] A thermosetting composition according to any one of [1] to

[12] , further comprising silicon dioxide particles with a primary particle size of 12 nm or less.

[14] A thermosetting composition according to any one of [1] to

[13] , wherein the thermal conductivity at 23°C after curing at 280°C for 6 minutes is 1.0 W / (m·K) or more.

[0017] The present invention provides a thermosetting composition that can mass-produce cured films of a consistent quality.

[0018] In this specification, for preferred numerical ranges (for example, ranges such as content), the lower limit value and the upper limit value described stepwise can be combined independently. For example, from the description "preferably 10 to 90, more preferably 30 to 60", it is also possible to combine the "preferred lower limit value (10)" and the "more preferred upper limit value (60)" to obtain "10 to ǀǀEND]]

[0019] 〔Silane compound polymer〕 The thermosetting composition of the present invention contains, as component (A), a silane compound polymer having a repeating unit [repeating unit (1)] represented by the following formula (a-1) (hereinafter, may be referred to as "silane compound polymer (A)").

[0020]

[0021] In formula (a-1), R １ represents an unsubstituted or substituted aryl group having 6 to 20 carbon atoms.

[0022] R １ The number of carbon atoms of the unsubstituted or substituted aryl group having 6 to 20 carbon atoms of R is preferably 6 to 15, more preferably 6 to 10. This number of carbon atoms means the number of carbon atoms of the part excluding the substituent (aryl group part). Therefore, when R １ is a "substituted aryl group having 6 to 20 carbon atoms", the number of carbon atoms of R １ may exceed 20.

[0023] R １ Examples of the unsubstituted aryl group having 6 to 20 carbon atoms of R include a phenyl group, a 1-naphthyl group, a 2-naphthyl group, a tolyl group, a xylyl group, etc.

[0024] R １ The number of atoms of the substituent of the substituted aryl group having 6 to 20 carbon atoms of R (excluding the number of hydrogen atoms) is usually 1 to 30, preferably 1 to 20. Examples of the substituent of the substituted aryl group having 6 to 20 carbon atoms include halogen atoms such as a fluorine atom, a chlorine atom, and a bromine atom; alkoxy groups such as a methoxy group and an ethoxy group; a cyano group; an amino group; an acryloyloxy group; a methacryloyloxy group; an epoxy group; etc.

[0025] Using a silane compound polymer having repeating units (1) as the curing component of a thermosetting composition makes it easier to obtain a thick cured film. Furthermore, depending on the type of repeating units derived from the trifunctional silane compound, there is a risk of cracking occurring in the cured film, but using a silane compound polymer having repeating units (1) as the curing component of a thermosetting composition makes it easier to obtain a cured film that is less prone to cracking.

[0026] A preferred silane compound polymer (A) is a silane compound polymer having a repeating unit (1) and a repeating unit represented by the following formula (a-2) [repeating unit (2)] (hereinafter sometimes referred to as "silane compound polymer (A1)").

[0027]

[0028] In formula (a-2), R ２ This represents an unsubstituted or substituted alkyl group having 1 to 16 carbon atoms.

[0029] R ２ The unsubstituted or substituted alkyl group having 1 to 16 carbon atoms preferably has 1 to 10 carbon atoms, and more preferably 1 to 5 carbon atoms. Note that this carbon number refers to the carbon number of the part excluding the substituent (the alkyl group part). Therefore, R ２ If R is a "alkyl group having 1 to 16 carbon atoms with substituents", ２ The number of carbon atoms can sometimes exceed 16.

[0030] R ２ The unsubstituted C1-C16 alkyl group may be a linear alkyl group or a branched alkyl group. ２ Examples of unsubstituted C1-C16 alkyl groups include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, n-pentyl group, n-hexyl group, n-octyl group, n-nonyl group, and n-decyl group.

[0031] R ２The number of substituent atoms (excluding hydrogen atoms) of a C1-C16 alkyl group having substituents is usually 1 to 30, preferably 1 to 20. Examples of substituents of a C1-C16 alkyl group having substituents include halogen atoms such as fluorine, chlorine, and bromine atoms; aryl groups such as phenyl groups; alkoxy groups such as methoxy and ethoxy groups; cyano groups; amino groups; acryloyloxy groups; methacryloyloxy groups; epoxy groups; and the like.

[0032] Silane compound polymers having repeating units (2) tend to exhibit excellent curability. Therefore, by using silane compound polymer (A1) as a curing component in a thermosetting composition, it becomes easier to obtain a thermosetting composition that cures sufficiently in a short time.

[0033] In the silane compound polymer (A1), the amount of repeating unit (1) is preferably 20 to 80 mol% relative to the total amount of repeating unit (1) and repeating unit (2). The lower limit of the amount of repeating unit (1) is more preferably 30 mol%, and even more preferably 40 mol%. The upper limit of the amount of repeating unit (1) is more preferably 70 mol%, and even more preferably 60 mol%.

[0034] In the silane compound polymer (A1), the total amount of repeating units (1) and (2) is preferably 70 to 100 mol%, more preferably 80 to 100 mol%, and even more preferably 90 to 100 mol% relative to the total amount of repeating units in the silane compound polymer (A1). By using a thermosetting composition in which the amount of repeating units (1) is within the above range, a thick cured film can be efficiently formed.

[0035] When the silane compound polymer (A1) has repeating units other than repeating unit (1) and repeating unit (2) [repeating unit (X)], examples of repeating unit (X) include repeating units derived from monofunctional silane compounds such as trimethylmethoxysilane, repeating units derived from difunctional silane compounds such as dimethyldimethoxysilane, repeating units derived from trifunctional silane compounds (excluding repeating units (1) and (2)), and repeating units derived from tetrafunctional silane compounds such as tetramethoxysilane.

[0036] A preferred silane compound polymer (A) other than silane compound polymer (A1) is the following formula (a-3):

[0037]

[0038] A repeating unit represented by [repeating unit (3)], the repeating unit (1), and the following formula (a-4)

[0039]

[0040] [R ３ , R ４ Each of these independently represents an unsubstituted or substituted C1-C16 alkyl group, or an unsubstituted or substituted C6-C20 aryl group. Examples include silane compound polymers having a repeating unit represented by ] [repeating unit (4)] and (hereinafter sometimes referred to as "silane compound polymer (A2)").

[0041] R ３ , R ４ The unsubstituted or substituted alkyl groups having 1 to 16 carbon atoms are R ２ R is an unsubstituted or substituted alkyl group having 1 to 16 carbon atoms, similar to those described above. ３ , R ４ The unsubstituted or substituted aryl group having 6 to 20 carbon atoms is R １ These are the same as those described earlier, as unsubstituted or substituted aryl groups having 6 to 20 carbon atoms.

[0042] Conventionally, when manufacturing silane compound polymers, depending on the type of monomer used, oligomers could be formed as a by-product, sometimes resulting in a rough surface on the cured film of the thermosetting composition. However, when manufacturing silane compound polymers having repeating units (3) or (4), the formation of these oligomers tends to be suppressed. Furthermore, by using a silane compound polymer having repeating units (4) as the curing component of the thermosetting composition, it becomes easier to obtain a cured film that is less prone to cracking.

[0043] In the silane compound polymer (A2), it is preferable that the amount of repeating unit (3) is 20 to 50 mol%, the amount of repeating unit (1) is 30 to 78 mol%, and the amount of repeating unit (4) is 2 to 40 mol%, relative to the total amount of repeating unit (3), repeating unit (1), and repeating unit (4). The amount of repeating unit (3) is more preferably 22 mol% or more, even more preferably 24 mol% or more, and particularly preferably 26 mol% or more, relative to the total amount of repeating unit (3), repeating unit (1), and repeating unit (4). It is also more preferably 44 mol% or less, even more preferably 38 mol% or less, and particularly preferably 33 mol% or less. The amount of repeating unit (1) is more preferably 35 mol% or more, even more preferably 40 mol% or more, and particularly preferably 45 mol% or more, relative to the total amount of repeating unit (3), repeating unit (1), and repeating unit (4). Furthermore, it is more preferable that the amount be 74 mol% or less, even more preferable that it be 70 mol% or less, and particularly preferable that it be 66 mol% or less. The amount of repeating unit (4) is more preferably 4 mol% or more, even more preferable that it be 6 mol% or more, and particularly preferable that it be 8 mol% or more, relative to the total amount of repeating unit (3), repeating unit (1), and repeating unit (4). Furthermore, it is more preferable that it be 34 mol% or less, even more preferable that it be 28 mol% or less, and particularly preferable that it be 22 mol% or less. A silane compound polymer (A2) that satisfies the above requirements is more suitable as a curing component when forming a cured film that is thick and less prone to cracking and surface roughness.

[0044] In the silane compound polymer (A2), the total amount of repeating units (3), (1), and (4) is preferably 50 to 100 mol%, more preferably 70 to 100 mol%, and even more preferably 90 to 100 mol% relative to the total amount of repeating units in the silane compound polymer (A2).

[0045] When the silane compound polymer (A2) has repeating units other than repeating units (3), repeating unit (1), and repeating unit (4) [repeating unit (Y)], examples of repeating unit (Y) include repeating units derived from monofunctional silane compounds such as trimethylmethoxysilane, repeating units derived from difunctional silane compounds (excluding repeating unit (4)), and repeating units derived from trifunctional silane compounds (excluding repeating unit (1)).

[0046] The mass-average molecular weight (Mw) of the silane compound polymer (A) is preferably 1,000 to 10,000, more preferably 1,200 to 9,000, and even more preferably 1,500 to 8,000. The molecular weight distribution (Mw / Mn) of the silane compound polymer (A) is not particularly limited, but is usually 1.0 to 10.0, preferably 1.1 to 6.0. Silane compound polymers (A) with a mass-average molecular weight and molecular weight distribution (Mw / Mn) within the above range are suitably used as curable components in thermosetting compositions. The mass-average molecular weight (Mw) and number-average molecular weight (Mn) can be determined, for example, as standard polystyrene equivalent values ​​by gel permeation chromatography (GPC) using tetrahydrofuran (THF) as the solvent.

[0047] The silane compound polymer (A) is preferably thermosetting. The thermosetting silane compound polymer (A) is suitably used as a curing component in a thermosetting composition. In the present invention, "thermosetting" in silane compound polymers and compositions refers to the property of curing by heating alone, even without the presence of a curing catalyst.

[0048] The content of the silane compound polymer (A) is preferably 5 to 50% by mass, more preferably 10 to 40% by mass, and even more preferably 15 to 30% by mass, of the total amount of components constituting the thermosetting composition (excluding the solvent). By using a thermosetting composition with a silane compound polymer (A) content within the above range, a cured film that is thick and has excellent impact resistance can be efficiently formed.

[0049] The method for producing the silane compound polymer (A) is not particularly limited. For example, the silane compound polymer (A) can be produced by performing a hydrolysis polycondensation step (step PO) of an alkoxysilane compound (monomer) corresponding to a desired repeating unit in the presence of water and an acid catalyst.

[0050] Examples of alkoxysilane compounds include trifunctional silane compounds represented by the following formula (a-5).

[0051]

[0052] In formula (a-5), R １ This expresses the same meaning as above. OR ５ OR represents an alkoxy group. ５ They may be the same as each other, or they may be different.

[0053] OR ５ The number of carbon atoms in the alkoxy group represented by is preferably 1 to 6, and more preferably 1 to 3. ５ Examples of alkoxy groups represented by this symbol include methoxy groups, ethoxy groups, and propoxy groups.

[0054] Specific examples of trifunctional silane compounds represented by formula (a-5) include phenyltrimethoxysilane, phenyltriethoxysilane, and phenyltripropoxysilane. These trifunctional silane compounds can be used individually or in combination of two or more.

[0055] By using a trifunctional silane compound represented by formula (a-5), a silane compound polymer having a repeating unit (1) can be obtained.

[0056] When producing the silane compound polymer (A1), in addition to the trifunctional silane compound represented by formula (a-5), the trifunctional silane compound represented by the following formula (a-6) is used.

[0057]

[0058] In formula (a-6), R ２ This expresses the same meaning as above. OR ６ OR represents an alkoxy group. ６They may be the same as each other, or they may be different.

[0059] OR ６ The number of carbon atoms in the alkoxy group represented by is preferably 1 to 6, and more preferably 1 to 3. ６ Examples of alkoxy groups represented by this symbol include methoxy groups, ethoxy groups, and propoxy groups.

[0060] Specific examples of trifunctional silane compounds represented by formula (a-6) include methyltrimethoxysilane, methyltriethoxysilane, and methyltripropoxysilane. These trifunctional silane compounds can be used individually or in combination of two or more.

[0061] By using a trifunctional silane compound represented by formula (a-6), a silane compound polymer having a repeating unit (2) can be obtained.

[0062] When producing the silane compound polymer (A2), in addition to the trifunctional silane compound represented by formula (a-5), a tetrafunctional silane compound represented by the following formula (a-7) and a difunctional silane compound represented by the following formula (a-8) are used.

[0063]

[0064] In formula (a-7), OR ７ OR represents an alkoxy group. ７ They may be the same as each other, or they may be different.

[0065] OR ７ The number of carbon atoms in the alkoxy group represented by is preferably 1 to 6, and more preferably 1 to 3. ７ Examples of alkoxy groups represented by this symbol include methoxy groups, ethoxy groups, and propoxy groups.

[0066] Specific examples of the tetrafunctional silane compounds represented by formula (a-7) include tetramethoxysilane, tetraethoxysilane, and tetrapropoxysilane. These tetrafunctional silane compounds can be used individually or in combination of two or more.

[0067] By using a tetrafunctional silane compound represented by formula (a-7), a silane compound polymer having a repeating unit (3) can be obtained.

[0068]

[0069] In formula (a-8), R ３ , R ４ This expresses the same meaning as above. OR ８ OR represents an alkoxy group. ８ They may be the same as each other, or they may be different.

[0070] OR ８ The number of carbon atoms in the alkoxy group represented by is preferably 1 to 6, and more preferably 1 to 3. ８ Examples of alkoxy groups represented by this symbol include methoxy groups, ethoxy groups, and propoxy groups.

[0071] Specific examples of the difunctional silane compounds represented by formula (a-8) include dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldipropoxysilane, methylphenyldimethoxysilane, and diphenyldimethoxysilane. These difunctional silane compounds can be used individually or in combination of two or more.

[0072] By using a bifunctional silane compound represented by formula (a-8), a silane compound polymer having repeating units (4) can be obtained.

[0073] In process PO, hydrolyzable groups contained in the monomer (for example, "OR" in formula (a-5) ５ It is preferable to add an amount of water to the reaction system that is sufficient to hydrolyze the alkoxy group, etc. The amount of water added is preferably such that the mol ratio M of water to alkoxy group, as derived by the following formula (F1), is 1.0 or more, more preferably 1.0 to 5.0, and even more preferably 1.0 to 3.0.

[0074]

[0075] In formula (F1), M Ｈ２Ｏ This is the amount of water (in moles) added to the reaction system, and M ＯＲThis is the total number of alkoxy groups (total moles) in the monomer. For example, if 18.0 mol of water is added to 1.0 mol of a tetrafunctional silane compound, 1.0 mol of a trifunctional silane compound, and 1.0 mol of a difunctional silane compound, the value of the mole ratio M is 18.0 / (4 × 1.0 + 3 × 1.0 + 2 × 1.0) (= 2.0).

[0076] A molar ratio M of 1.0 or higher allows the hydrolysis reaction of the alkoxysilane compound to proceed sufficiently, making it easier to obtain a silane compound polymer (A) with excellent curability.

[0077] Examples of acid catalysts used in the process PO include inorganic acids such as phosphoric acid, hydrochloric acid, boric acid, sulfuric acid, and nitric acid; and organic acids such as formic acid, citric acid, acetic acid, methanesulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid, and p-toluenesulfonic acid. Among these, at least one selected from phosphoric acid, hydrochloric acid, boric acid, sulfuric acid, formic acid, citric acid, acetic acid, and methanesulfonic acid is preferred.

[0078] The amount of acid catalyst used is typically 0.05 to 10 mol%, preferably 0.1 to 5 mol%, relative to the total amount of monomers. By adjusting the amount of acid catalyst used, the polycondensation reaction can be controlled appropriately, and a silane compound polymer (A) with the desired molecular weight can be obtained.

[0079] Step PO can be carried out, for example, by placing an alkoxysilane compound, water, and an acid catalyst in a reaction vessel and stirring the resulting mixture. In addition to these components, an organic solvent may also be present in the reaction vessel. The presence of an organic solvent in the reaction vessel allows the polymerization reaction to continue even if a solid silane compound polymer (A) is formed during the polymerization reaction.

[0080] The organic solvent used in the process PO is not particularly limited as long as it dissolves the alkoxysilane compound used as a raw material. However, a high-boiling point solvent is preferred as the organic solvent because it does not easily volatilize during the process PO and the process PO can be carried out stably. The boiling point of the organic solvent is preferably 110°C or higher, more preferably 130°C or higher, and even more preferably 150°C or higher. Furthermore, the boiling point of the organic solvent is preferably 300°C or lower, more preferably 250°C or lower, and even more preferably 200°C or lower.

[0081] Examples of high-boiling point solvents include polyether solvents such as dipropylene glycol dimethyl ether (boiling point 171°C), diethylene glycol dimethyl ether (boiling point 162°C), and diethylene glycol ethyl methyl ether (boiling point 176°C); ester solvents such as γ-butyrolactone (boiling point 204°C), ethyl lactate (boiling point 154°C), 3-methoxybutyl acetate (boiling point 171°C), and ethylene glycol monoethyl ether acetate (boiling point 156°C); ketone solvents such as cyclohexanone (boiling point 156°C); amide solvents such as N,N-dimethylformamide (boiling point 153°C), N,N-dimethylacetamide (boiling point 165°C), and N-methylpyrrolidone (boiling point 202°C); and sulfoxide solvents such as dimethyl sulfoxide (boiling point 189°C). Among these, polyether solvents are preferred because they do not react easily even at high temperatures.

[0082] When an organic solvent is used in step PO, for example, an amount of organic solvent is used that is preferably 0.05 to 3 times, more preferably 0.1 to 2.2 times, by volume, relative to the alkoxysilane compound. Furthermore, when the reaction solution obtained in step PO is used directly in the preparation of the thermosetting composition of the present invention, it is preferable to adjust the amount of organic solvent used considering the concentration of the silane compound polymer (A) in the thermosetting composition.

[0083] The reaction conditions for process PO are not particularly limited. The reaction temperature for process PO is usually 0 to 180°C, preferably 10 to 170°C. The reaction time for process PO is usually 30 minutes to 50 hours, preferably 1 to 24 hours.

[0084] Process PO may be carried out under constant conditions from start to finish (i.e., it may have one step), or it may have multiple steps with different reaction conditions.

[0085] After step PO, the resulting reaction solution may be used directly to prepare the thermosetting composition of the present invention, or a step (step PU) may be performed to purify the silane compound polymer (A) produced in step PO. By performing step PU, a high-purity silane compound polymer (A) can be obtained.

[0086] One example of a process for PU is a purification process by solvent extraction. An example of a purification process by solvent extraction is one which has the following steps: (Step PU-I) After volatilizing the solvent from the reaction solution as needed, water-immiscible organic solvent or water is added, the mixture is stirred, and then allowed to stand to separate the organic phase and the aqueous phase. (Step PU-II) The organic phase produced in Step PU-I is separated, and the organic phase is washed with water as needed. (Step PU-III) The organic phase separated in Step PU-II is concentrated and dried.

[0087] The amount of solvent and the type of organic solvent added in step PU-I are not particularly limited, as long as they ultimately separate into an organic phase and an aqueous phase.

[0088] The silane compound polymer (A) is usually contained in the organic phase. Therefore, in step PU-II, the organic phase produced in step PU-I is separated. After this, the organic phase may be washed with water according to a conventional method.

[0089] Step PU-III can be carried out according to conventional methods, such as concentration treatment using an evaporator and vacuum drying treatment.

[0090] [Thermally conductive filler] The thermosetting composition of the present invention contains, as component (B), one or more fillers selected from the group consisting of alumina, aluminum nitride, and zinc oxide (hereinafter sometimes referred to as "filler (B)"). Because the thermosetting composition of the present invention contains filler (B), its cured film has excellent thermal conductivity.

[0091] It is preferable that at least one of the fillers (B) is aluminum nitride. Using aluminum nitride as filler (B) makes it easier to obtain a cured film with superior thermal conductivity. Furthermore, since thermosetting compositions containing aluminum nitride tend to have a high thixotropy, using a thermosetting composition containing aluminum nitride allows for the mass production of cured films of consistent quality.

[0092] The aluminum nitride content is preferably 50% by volume or more, and more preferably 53% by volume or more, relative to the total amount of components constituting the thermosetting composition (excluding the solvent). There is no particular upper limit, but it is preferably 75% by volume or less, and more preferably 70% by volume or less. When the aluminum nitride content is 50% by volume or more, relative to the total amount of components constituting the thermosetting composition (excluding the solvent), it is easier to obtain a cured film with excellent thermal conductivity.

[0093] Particle size of filler (B) (D ５０ The particle size (D) is preferably 0.1 to 20 μm, and more preferably 0.2 to 10 μm. ５０ The cured film of a thermosetting composition containing filler (B) with a particle size of 0.1 to 20 μm exhibits superior thermal conductivity. In this invention, the particle size (D ５０ ) refers to the volume-based cumulative 50% particle size obtained by laser diffraction and scattering methods.

[0094] Examples of filler (B) shapes include flaky, plate-like, membranous, cylindrical, prismatic, elliptical, flattened, and spherical shapes.

[0095] The content of filler (B) is preferably 100 to 1,000 parts by mass, more preferably 200 to 900 parts by mass, and even more preferably 300 to 700 parts by mass, per 100 parts by mass of silane compound polymer (A). By using a thermosetting composition with a filler (B) content within the above range, a cured film that is thick and has excellent impact resistance and thermal conductivity can be efficiently formed.

[0096] [Thermosetting Composition] The thermosetting composition of the present invention can be prepared, for example, by mixing a silane compound polymer (A) and a filler (B) in a solvent. Alternatively, filler (B) may be added to a solution of silane compound polymer (A) and mixed. When mixing silane compound polymer (A) and filler (B), known mixing means such as a rotary-orbiting agitator can be used.

[0097] Examples of solvents constituting the thermosetting composition include those previously described as solvents for the synthesis of silane compound polymers (A).

[0098] The thermosetting composition of the present invention may contain components other than the silane compound polymer (A), filler (B), and solvent. Examples of such components include fillers other than filler (B) (hereinafter sometimes referred to as "filler (C)").

[0099] Silicon dioxide can be used as a filler (C). Since silicon dioxide does not have a very high thermal conductivity, it does not contribute much to improving the thermal conductivity of the cured film. However, thermosetting compositions containing silicon dioxide tend to have a high thixotropy, so by using thermosetting compositions containing silicon dioxide, it is possible to mass-produce cured films of a certain quality.

[0100] The primary particle size of silicon dioxide is preferably 12 nm or less, more preferably 10 nm or less. The average primary particle size of fine particles such as silicon dioxide can be determined by observing the shape of the fine particles using a transmission electron microscope.

[0101] When the thermosetting composition of the present invention contains filler (C), the content of filler (C) is preferably 0.1 to 30 parts by mass, and more preferably 1 to 15 parts by mass, per 100 parts by mass of silane compound polymer (A).

[0102] The thermosetting composition of the present invention exhibits excellent thixotropy. The thixotropy of the thermosetting composition of the present invention is 1.1 or higher, preferably 1.5 or higher, and more preferably 5 or higher. There is no particular upper limit, but it is usually 20 or lower. The thixotropy of the thermosetting composition of the present invention being 1.1 or higher allows for the mass production of cured films of consistent quality.

[0103] In this invention, the thixotropic index is defined as the shear rate of 1 s when using a rheometer with a cone plate having a radius of 50 mm and a cone angle of 1°, at 25°C. －１ The viscosity and shear rate at that time were 103 s. －１ The viscosity was measured at each of the following conditions, and the shear rate was 1 s. －１ The viscosity at which the shear rate is 103 s is －１ This refers to the value obtained by dividing by the viscosity at that time. Thermosetting compositions with a large thixotropy have the property that their viscosity decreases and they deform easily when force is applied, and their viscosity increases again when left standing (at rest). For this reason, it is believed that the thermosetting composition of the present invention is less likely to experience changes in the solid content concentration of the supernatant during the coating process, and that a cured film of consistent quality can be mass-produced.

[0104] Thermosetting compositions with a thixotropy index of 1.1 or higher can be efficiently prepared, for example, by using a filler (B) that has a thixotropy-enhancing effect, such as aluminum nitride, or by using a filler (C) that has a thixotropy-enhancing effect, such as silicon dioxide, in combination.

[0105] The thermosetting composition of the present invention hardens when heated, forming a cured product. The heating temperature for heat-curing the thermosetting composition of the present invention is typically 200 to 350°C. The heating time is typically 30 to 600 seconds, preferably 60 to 400 seconds.

[0106] The thermal conductivity of the cured product of the thermosetting composition of the present invention is preferably 1.0 W / (m·K) or higher, more preferably 1.5 to 10 W / (m·K). When a cured product with a thermal conductivity of 1.0 W / (m·K) or higher is formed as an insulating film for semiconductor devices, heat generated during the operation of the semiconductor device can be efficiently dissipated, thereby reducing failures of the semiconductor device. The thermal conductivity of the cured product of the thermosetting composition of the present invention can be calculated, for example, based on the thermal diffusivity obtained by measuring a cured product obtained by curing the thermosetting composition at 280°C for 6 minutes as a measurement sample at 23°C.

[0107] The thermosetting composition of the present invention is suitably used as an insulating film forming agent. When forming an insulating film using the thermosetting composition of the present invention, the thermosetting composition is usually applied, the resulting coating film is dried, and then the dried coating film is cured. When applying the thermosetting composition, a spin coating method is preferably used. When drying the coating film of the thermosetting composition, for example, the drying temperature is usually 100 to 200°C, preferably 120 to 180°C, and the drying time is usually 10 seconds to 3 hours, preferably 40 seconds to 2 hours. When curing the coating film after drying, for example, the curing temperature is usually 200 to 350°C, preferably 230 to 300°C, and the curing time is usually 30 to 600 seconds, preferably 60 to 400 seconds.

[0108] By using the thermosetting composition of the present invention, a relatively thick insulating film can be efficiently formed. The thickness of the insulating film is, for example, 0.1 to 50.0 μm, preferably 0.5 to 40.0 μm, and more preferably 1.0 to 30.0 μm.

[0109] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited in any way to the following examples.

[0110] [Average Molecular Weight Measurement] The mass-average molecular weight (Mw) of the silane compound polymer was measured using the following equipment and conditions: Equipment name: HLC-8220GPC manufactured by Tosoh Corporation Column: A sequentially linked column of "TSK guard column SuperH-H", "TSK gel SuperHM-H", "TSK gel SuperHM-H", and "TSK gel SuperH2000" Solvent: Tetrahydrofuran Standard substance: Polystyrene Injection volume: 20 μl Measurement temperature: 40°C Flow rate: 0.6 ml / min Detector: Differential refractometer

[0111] [Production Example 1] Tetraethoxysilane (320 mmol, 66.7 g), phenyltrimethoxysilane (480 mmol, 95.2 g), and dimethyldiethoxysilane (200 mmol, 29.7 g) were weighed into a flask, and dipropylene glycol dimethyl ether was added in an amount that resulted in a monomer concentration of 50% by mass. The contents of the flask were then heated to 50°C, and water (6240 mmol, 112.4 g) with formic acid (25 mmol, 1.2 g) was added, and the mixture was stirred for 20 hours. Then, while removing volatile matter by distillation, the contents of the flask were heated to 120°C and reacted at 120°C for 1 hour, and then heated to 160°C and reacted at 160°C for 1.5 hours. The reaction solution was then cooled to room temperature (25°C) to obtain a solution of silane compound polymer [polymer solution (1)]. The mass-average molecular weight of the silane compound polymer contained in polymer solution (1) was 4,900.

[0112] [Production Example 2] The polycondensation reaction of the silane compound was carried out in the same manner as in Production Example 1, except that the reaction time at 160°C was changed to 2 hours, to obtain a solution of the silane compound polymer [polymer solution (2)]. The mass-average molecular weight of the silane compound polymer contained in polymer solution (2) was 8,100.

[0113] [Production Example 3] The polycondensation reaction of the silane compound was carried out in the same manner as in Production Example 1, except that the reaction time at 160°C was changed to 1 hour, to obtain a solution of the silane compound polymer [polymer solution (3)]. The mass-average molecular weight of the silane compound polymer contained in polymer solution (3) was 3,900.

[0114] [Preparation Example 4] Methyltrimethoxysilane (500 mmol, 68.1 g) and phenyltrimethoxysilane (500 mmol, 99.1 g) were weighed into a flask, and dipropylene glycol dimethyl ether was added in an amount that resulted in a monomer concentration of 30% by mass. At 30°C, water (6000 mmol, 108.1 g) with formic acid (25 mmol, 1.2 g) was added dropwise over 30 minutes. The contents of the flask were then heated to 50°C and stirred for 2 hours, and while removing volatile matter, the temperature was raised to 120°C for 2 hours, and then to 160°C for 1 hour to allow the reaction to proceed. The reaction solution was then cooled to room temperature (25°C) to obtain a solution of the silane compound polymer [polymer solution (4)]. The mass-average molecular weight of the silane compound polymer contained in polymer solution (4) was 1,700.

[0115] [Examples 1-5, Comparative Examples 1-5] Polymer solutions (1) to (4) were diluted to the concentrations shown in Table 1, and then fillers were added to each dilution to the concentrations shown in Table 1. Using a rotary-orbiting agitator (manufactured by Thinky Co., Ltd., product name "ARE-400TWIN", rotation 1600 rpm, revolution 1600 rpm), the mixture was stirred at 23°C for 5 minutes to obtain a thermosetting composition.

[0116] [Viscosity Measurement] Using a rheometer (Anton Paar, product name "MCR302") with a cone plate of radius 50 mm and cone angle 1°, at 25°C, with a shear rate of 1 s. －１ The viscosity and shear rate at that time were 103 s. －１ The viscosity was measured for each of the following conditions. From the obtained measurements, the thixotropic index (shear rate 1 s) was used. －１ The viscosity / shear rate at that time is 103s. －１ The viscosity at that time was calculated.

[0117] [Measurement of Solid Content Concentration of the Supernatant] After stirring the thermosetting composition, a portion of the supernatant was taken and placed on an 8 cm square aluminum dish, and its mass was measured. The remaining thermosetting composition was left to stand for 1 hour. The collected thermosetting composition (supernatant), along with the aluminum dish, was heated at 150°C for 60 minutes to dry. The total mass of the dried thermosetting composition and the aluminum dish was measured, and the solid content concentration was calculated. The calculation formula is as follows: {(Total mass of the dried thermosetting composition and aluminum dish - Mass of the aluminum dish) / (Mass of the thermosetting composition before drying)} × 100 Next, a portion of the supernatant was similarly taken from the thermosetting composition that had been left to stand for 1 hour, its solid content concentration was calculated, and its change was examined.

[0118] [Workability] Workability was evaluated according to the following criteria based on the time required to draw up 1 mL of the thermosetting composition with a dropper: A: The thermosetting composition can be drawn up in less than 1 second. B: The thermosetting composition can be drawn up in more than 1 second but within 5 seconds. C: It takes more than 5 seconds to draw up the thermosetting composition, or it cannot be drawn up with a dropper.

[0119] [Thermal Conductivity] A thermosetting composition was applied to a polyethylene terephthalate film (38 μm thick). The resulting coating was dried at 120°C for 5 minutes. The dried coating was then peeled off the polyethylene terephthalate film and heated at 280°C for 6 minutes to obtain a cured film with a thickness of 100 μm. Next, the thermal diffusivity at 23°C was measured using a thermal diffusivity measuring device (ai-Phase Co., Ltd., product name "ai-Phase Mobile 1"). The specific heat and density of the cured film were also measured by the DSC method and the Archimedes method, respectively, and the thermal conductivity was calculated based on the following formula: Thermal conductivity [W / (m·K)] = Thermal diffusivity [m ２ / s] x density [kg / m ３ ] × Specific heat [J / (K·kg)]

[0120]

[0121] The thermosetting compositions obtained in Examples 1 to 5 form a cured film with excellent thermal conductivity. Furthermore, the thermosetting compositions obtained in Examples 2 to 5 have excellent thixotropy because they contain a large amount of aluminum nitride as component (B). Therefore, when these thermosetting compositions are allowed to stand, the change in the solid content concentration of the supernatant is small. On the other hand, the thermosetting compositions obtained in Comparative Examples 2 to 5 have poor thixotropy because they contain a large amount of alumina as component (B). Therefore, when these thermosetting compositions are allowed to stand, the change in the solid content concentration of the supernatant is large. However, as shown in Example 1, the problems of Comparative Examples 2 to 5 can be solved by adding silicon dioxide.

Claims

1. A thermosetting composition containing the following components (A) and (B), wherein the thixotropy index (shear rate is 1 s) －１ The viscosity / shear rate at that time is 103s. －１ A thermosetting composition having a viscosity of 1.1 or higher. (A) Component: The following formula (a-1) [R １ represents an unsubstituted or substituted aryl group having 6 to 20 carbon atoms. ] A silane compound polymer having a repeating unit [repeating unit (1)] represented by ] Component (B): One or more fillers selected from the group consisting of alumina, aluminum nitride, and zinc oxide 2. The component (A) is a silane compound polymer having the repeating unit (1) and a repeating unit [repeating unit (2)] represented by the following formula (a-2): [R ２ represents an unsubstituted or substituted alkyl group having 1 to 16 carbon atoms.], The thermosetting composition according to claim 1.

3. The thermosetting composition according to claim 2, wherein the amount of the repeating unit (1) is 20 to 80 mol% of the total amount of repeating unit (1) and repeating unit (2).

4. The thermosetting composition according to claim 2, wherein the total amount of repeating unit (1) and repeating unit (2) is 70 to 100 mol% of the total amount of repeating units of the silane compound polymer.

5. The above component (A) is given by the following formula (a-3) A repeating unit represented by [repeating unit (3)], the repeating unit (1), and the following formula (a-4) [R ３ , R ４ Each of these independently represents an unsubstituted or substituted C1-C16 alkyl group, or an unsubstituted or substituted C6-C20 aryl group. The thermosetting composition according to claim 1 is a silane compound polymer having a repeating unit [repeating unit (4)] represented by ].

6. The thermosetting composition according to claim 5, wherein, with respect to the total amount of repeating units (3), (1), and (4), the amount of repeating unit (3) is 20 to 50 mol%, the amount of repeating unit (1) is 30 to 78 mol%, and the amount of repeating unit (4) is 2 to 40 mol%.

7. The thermosetting composition according to claim 5, wherein the total amount of repeating unit (3), repeating unit (1), and repeating unit (4) is 50 to 100 mol% of the total repeating units of the silane compound polymer.

8. The thermosetting composition according to claim 1, wherein the mass-average molecular weight (Mw) of component (A) is 1,000 to 10,000.

9. The thermosetting composition according to claim 1, wherein component (A) is thermosetting.

10. The thermosetting composition according to claim 1, wherein the content of component (A) is 5 to 50% by mass of the total amount of components constituting the thermosetting composition (excluding the solvent).

11. The thermosetting composition according to claim 1, wherein the aluminum nitride content is 50% by volume or more relative to the total amount of components constituting the thermosetting composition (excluding the solvent).

12. The thermosetting composition according to claim 1, wherein the content of component (B) is 100 to 1,000 parts by mass per 100 parts by mass of component (A).

13. The thermosetting composition according to claim 1, further comprising silicon dioxide particles having a primary particle diameter of 12 nm or less.

14. The thermosetting composition according to claim 1, wherein the thermal conductivity at 23°C after curing at 280°C for 6 minutes is 1.0 W / (m·K) or more.

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