Resin varnish, and prepreg, resin film, laminate, printed wiring board and semiconductor package manufacturing method

Abstract

To provide a resin varnish from which a resin composition excellent in moldability can be obtained even if a drying temperature is increased, and a prepreg, a resin film, a laminate, a printed wiring board and a semiconductor package manufacturing method, each of which is obtained using the resin varnish.SOLUTION: A resin varnish is provided, containing (A) one or more kinds selected from the group consisting of a maleimide resin having one or more N-substituted maleimide groups and a derivative of the maleimide resin, (B) a polyphenylene ether-based resin having a functional group containing an ethylenic unsaturated bond, (C) a styrenic thermoplastic resin having a weight average molecular weight (Mw) of more than 10,000 and less than 100,000, (D) an organic peroxide, and (E) an organic solvent. A prepreg, a resin film, a laminate, a printed wiring board and a semiconductor package manufacturing method are also provided each of which is obtained using the resin varnish.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present embodiment relates to a resin varnish, and a method for producing a prepreg, a resin film, a laminate, a printed wiring board, and a semiconductor package. [Background technology]

[0002] In electronic devices such as mobile communication devices such as mobile phones, their base station equipment, network infrastructure devices such as servers and routers, and large computers, the speed and capacity of the signals they use are increasing year by year. Accordingly, the substrate materials for the printed wiring boards mounted on these electronic devices are required to have dielectric properties that can reduce the transmission loss of high-frequency signals [hereinafter sometimes referred to as "high-frequency properties"], that is, low relative dielectric constant and low dielectric loss tangent.

[0003] Patent Document 1 discloses a curable resin composition containing a naphthol novolac epoxy resin and a polyphenylene ether resin, the curable resin composition having a low relative dielectric constant and dielectric dissipation factor and excellent heat resistance of the resulting cured product, which can be used as an insulating layer for a printed wiring board. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-185080 A Summary of the Invention [Problem to be solved by the invention]

[0005] Insulating materials such as prepregs are usually produced by a method in which a varnish containing a resin or the like is impregnated or coated on the material, followed by drying. For insulating materials such as prepregs, it is necessary to suppress the resin flow of the molten resin composition during press molding in order to improve the thickness accuracy of the molded product. Usually, the resin flow can be suppressed by increasing the degree of curing of the resin composition, so in insulating materials manufactured by drying a resin varnish, it is effective to increase the drying temperature of the resin varnish. On the other hand, if the drying temperature of the resin varnish is increased, the melt viscosity of the resin composition obtained by drying increases, which causes problems such as the generation of voids when embedding a conductor circuit, which deteriorates moldability.

[0006] In view of the current situation, an object of the present embodiment is to provide a resin varnish that can give a resin composition that has excellent moldability even when the drying temperature is high, and a method for producing a prepreg, a resin film, a laminate, a printed wiring board, and a semiconductor package using the resin varnish. [Means for solving the problem]

[0007] As a result of extensive research into solving the above problems, the present inventors have found that the above problems can be solved by the present embodiment described below. [1] (A) one or more selected from the group consisting of maleimide resins having one or more N-substituted maleimide groups and derivatives of the maleimide resins; (B) a polyphenylene ether resin having a functional group containing an ethylenically unsaturated bond; (C) a styrene-based thermoplastic resin having a weight average molecular weight (Mw) of more than 10,000 and less than 100,000; (D) an organic peroxide; (E) an organic solvent; A resin varnish containing [2] The resin varnish according to the above [1], wherein the content of the component (D) is 0.01 to 10 parts by mass per 100 parts by mass of the component (A). [3] The resin varnish according to the above [1] or [2], wherein the component (D) has a one-hour half-life temperature of 100 to 200°C. [4] The resin varnish according to any one of the above [1] to [3], wherein the component (B) has a functional group containing an ethylenically unsaturated bond at a terminal thereof. [5] The resin varnish according to any one of the above [1] to [4], wherein the functional group containing an ethylenically unsaturated bond that the component (B) has is a (meth)acryloyl group. [6] The resin varnish according to any one of the above [1] to [5], further comprising (F) an inorganic filler. [7] The resin varnish according to any one of the above [1] to [6], further comprising (G) a curing accelerator other than an organic peroxide. [8] A method for producing a prepreg, using the resin varnish according to any one of [1] to [7] above. [9] A method for producing a resin film, using the resin varnish according to any one of the above [1] to [7].

[10] A method for producing a laminate using a prepreg produced by the method for producing a prepreg described in [8] above.

[11] A method for producing a printed wiring board using a prepreg produced by the method for producing a prepreg described in [8] above or a resin film produced by the method for producing a resin film described in [9] above.

[12] A method for manufacturing a semiconductor package using a printed wiring board manufactured by the method for manufacturing a printed wiring board described in

[11] above. Effect of the Invention

[0008] According to the present embodiment, it is possible to provide a resin varnish which can provide a resin composition which has excellent moldability even when the drying temperature is high, and a method for producing a prepreg, a resin film, a laminate, a printed wiring board, and a semiconductor package using the resin varnish. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] In this specification, a numerical range indicated using "~" indicates a range that includes the numerical values ​​before and after "~" as the minimum and maximum values, respectively. For example, the expression "numerical range "X to Y" (X and Y are real numbers) means a numerical range that is equal to or greater than X and equal to or less than Y. In this specification, the expression "equal to or greater than X" means X and a numerical value that exceeds X. In this specification, the expression "equal to or less than Y" means Y and a numerical value that is less than Y. Each lower limit and upper limit of a numerical range described herein may be arbitrarily combined with the lower limit or upper limit of any other numerical range. In the numerical ranges described in this specification, the lower or upper limit of the numerical range may be replaced with values ​​shown in the examples.

[0010] Unless otherwise specified, each of the components and materials exemplified in this specification may be used alone or in combination of two or more. In this specification, the content of each component in a resin varnish means, unless otherwise specified, the total amount of the multiple substances present in the resin varnish when multiple substances corresponding to each component are present in the resin varnish.

[0011] The expression "containing XX" as used herein means both containing XX in a reacted state when XX is capable of reacting, and simply containing XX.

[0012] In this specification, the term "solid content" refers to components other than the solvent, and includes those that are liquid, syrup-like, or waxy at room temperature. Here, in this specification, room temperature refers to 25°C.

[0013] In this specification, "(meth)acryloyl" means "acryloyl" and its corresponding "methacryloyl".

[0014] The weight average molecular weight (Mw) in this specification means a value measured in terms of polystyrene by gel permeation chromatography (GPC), and specifically, can be measured by the method described in the examples.

[0015] The mechanism of action described in this specification is speculation and does not limit the mechanism by which the effects of the present embodiment are achieved.

[0016] Any combination of the descriptions in this specification is also included in this embodiment.

[0017] [Resin varnish] The resin varnish of this embodiment is (A) one or more selected from the group consisting of maleimide resins having one or more N-substituted maleimide groups and derivatives of the maleimide resins, (B) a polyphenylene ether resin having a functional group containing an ethylenically unsaturated bond; (C) a styrene-based thermoplastic resin having a weight average molecular weight (Mw) of more than 10,000 and less than 100,000; (D) an organic peroxide; (E) an organic solvent; Contains:

[0018] In the following description, one or more types selected from the group consisting of maleimide resins having one or more N-substituted maleimide groups and derivatives of the maleimide resins may be referred to as "(A) maleimide-based resin". Furthermore, (B) a polyphenylene ether resin having a functional group containing an ethylenically unsaturated bond may be referred to as "(B) polyphenylene ether resin." In addition, (C) a styrene-based thermoplastic resin having a weight-average molecular weight (Mw) of more than 10,000 and less than 100,000 may be referred to as "(C) a styrene-based thermoplastic resin". Furthermore, each component may be referred to as component (A), component (B), etc. Hereinafter, each component that may be contained in the resin varnish of the present embodiment will be described in order.

[0019] <(A) Maleimide resin> The (A) maleimide-based resin is at least one type selected from the group consisting of maleimide resins having at least one N-substituted maleimide group and derivatives of the maleimide resins. The (A) maleimide-based resin may be used alone or in combination of two or more kinds.

[0020] In the following description, a maleimide resin having one or more N-substituted maleimide groups may be referred to as a "maleimide resin (AX)" or a "(AX) component." Furthermore, a maleimide resin derivative having one or more N-substituted maleimide groups may be referred to as a "maleimide resin derivative (AY)" or an "(AY) component".

[0021] (Maleimide resin (AX)) The maleimide resin (AX) is not particularly limited as long as it is a maleimide resin having one or more N-substituted maleimide groups.

[0022] From the viewpoints of conductor adhesion and heat resistance, the maleimide resin (AX) is preferably a maleimide resin having two or more N-substituted maleimide groups, is preferably an aromatic maleimide resin having two or more N-substituted maleimide groups, and is more preferably an aromatic bismaleimide resin having two N-substituted maleimide groups. In this specification, the term "aromatic maleimide resin" refers to a compound having an N-substituted maleimide group directly bonded to an aromatic ring, and the term "aromatic bismaleimide resin" refers to a compound having two N-substituted maleimide groups directly bonded to an aromatic ring. In addition, in this specification, the term "aromatic polymaleimide resin" refers to a compound having three or more N-substituted maleimide groups directly bonded to an aromatic ring. In addition, in this specification, the term "aliphatic maleimide resin" means a compound having an N-substituted maleimide group directly bonded to an aliphatic hydrocarbon.

[0023] As the maleimide resin (AX), a maleimide resin represented by the following general formula (A1-1) [hereinafter, sometimes referred to as "maleimide resin (A1)"] is preferable.

[0024] [ka] (In the formula, X A11 is a divalent organic group.

[0025] X in the above general formula (A1-1) A11 is a divalent organic group. X in the above general formula (A1-1) A11 Examples of the divalent organic group represented by the formula include a divalent group represented by the following general formula (A1-2), a divalent group represented by the following general formula (A1-3), a divalent group represented by the following general formula (A1-4), a divalent group represented by the following general formula (A1-5), and a divalent group represented by the following general formula (A1-6).

[0026] [ka] (In the formula, R A11 is an aliphatic hydrocarbon group having 1 to 5 carbon atoms or a halogen atom. A11 is an integer from 0 to 4. * represents a binding site.

[0027] R in the above general formula (A1-2) A11 Examples of the aliphatic hydrocarbon group having 1 to 5 carbon atoms represented by include an alkyl group having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, an n-pentyl group, etc.; an alkenyl group having 2 to 5 carbon atoms; an alkynyl group having 2 to 5 carbon atoms. The aliphatic hydrocarbon group having 1 to 5 carbon atoms may be either linear or branched. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. In the above general formula (A1-2), n A11 is an integer of 0 to 4, and from the viewpoint of availability, is preferably an integer of 0 to 2, more preferably 0 or 1, and even more preferably 0. A11 If is an integer equal to or greater than 2, multiple R A11 They may be the same or different.

[0028] [ka] (In the formula, R A12 and R A13 Each of X is independently an aliphatic hydrocarbon group having 1 to 5 carbon atoms or a halogen atom. A12 is an alkylene group having 1 to 5 carbon atoms, an alkylidene group having 2 to 5 carbon atoms, an ether group, a sulfide group, a sulfonyl group, a carbonyloxy group, a keto group, a single bond, or a divalent group represented by the following general formula (A1-3-1): A12 and n A13 are each independently an integer of 0 to 4. * represents a binding site.

[0029] R in the above general formula (A1-3) A12 and R A13 The aliphatic hydrocarbon group having 1 to 5 carbon atoms and the halogen atom represented by R A11 The same can be mentioned.

[0030] X in the above general formula (A1-3) A12 Examples of the alkylene group having 1 to 5 carbon atoms represented by include a methylene group, a 1,2-dimethylene group, a 1,3-trimethylene group, a 1,4-tetramethylene group, and a 1,5-pentamethylene group. X in the above general formula (A1-3) A12 Examples of the alkylidene group having 2 to 5 carbon atoms represented by include an ethylidene group, a propylidene group, an isopropylidene group, a butylidene group, an isobutylidene group, a pentylidene group, and an isopentylidene group.

[0031] In the above general formula (A1-3), n A12 and n A13 Each of n is independently an integer of 0 to 4. A12 or n A13 If is an integer equal to or greater than 2, multiple R A12 R A13 They may be the same or different from each other.

[0032] X in the above general formula (A1-3) A12 The divalent group represented by formula (A1-3-1) is as follows.

[0033] [ka] (In the formula, R A14 and R A15 Each of X is independently an aliphatic hydrocarbon group having 1 to 5 carbon atoms or a halogen atom. A13 is an alkylene group having 1 to 5 carbon atoms, an alkylidene group having 2 to 5 carbon atoms, an ether group, a sulfide group, a sulfonyl group, a carbonyloxy group, a keto group, or a single bond. A14 and n A15 are each independently an integer of 0 to 4. * represents a binding site.

[0034] R in the above general formula (A1-3-1) A14 and R A15 The aliphatic hydrocarbon group having 1 to 5 carbon atoms and the halogen atom represented by R A11 The same can be mentioned. X in the above general formula (A1-3-1) A13 The alkylene group having 1 to 5 carbon atoms and the alkylidene group having 2 to 5 carbon atoms represented by the above X A12 Among these, X A13 As the alkylidene group, an alkylidene group having 2 to 5 carbon atoms is preferable, an alkylidene group having 2 to 4 carbon atoms is more preferable, and an isopropylidene group is even more preferable.

[0035] In the above general formula (A1-3-1), n A14 and n A15 are each independently an integer of 0 to 4, and from the viewpoint of availability, each is preferably an integer of 0 to 2, more preferably 0 or 1, and even more preferably 0. A14 or n A15 If is an integer equal to or greater than 2, multiple R A14 R A15 They may be the same or different from each other.

[0036] [ka] (In the formula, n A16 is an integer between 0 and 10. * represents a binding site.)

[0037] In the above general formula (A1-4), n A16 From the viewpoint of availability, is preferably an integer of 0 to 5, more preferably an integer of 0 to 4, and further preferably an integer of 0 to 3.

[0038] [ka] (In the formula, n A17 is a number between 0 and 5. * represents a binding site.)

[0039] [ka] (In the formula, R A16 and R A17 are each independently a hydrogen atom or an aliphatic hydrocarbon group having 1 to 5 carbon atoms. A18 is an integer from 1 to 8. * represents a binding site.

[0040] R in the above general formula (A1-6) A16 and R A17 The aliphatic hydrocarbon group having 1 to 5 carbon atoms and the halogen atom represented by R A11 The same can be mentioned. In the above general formula (A1-6), n A18 is an integer of 1 to 8, preferably an integer of 1 to 5, more preferably an integer of 1 to 3, and even more preferably 1. A18 If is an integer equal to or greater than 2, multiple R A16 R A17 They may be the same or different from each other.

[0041] Examples of the maleimide resin (A1) include aromatic bismaleimide resins, aromatic polymaleimide resins, and aliphatic maleimide resins. Examples of the maleimide resin (A1) include bis(4-maleimidophenyl)methane, m-phenylene bismaleimide, 2,2-bis[4-(4-maleimidophenoxy)phenyl]propane, 4-methyl-1,3-phenylene bismaleimide, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, polyphenylmethane maleimide, biphenyl aralkyl type maleimide, aromatic bismaleimide resin having an indane skeleton, etc. Among these, 2,2-bis[4-(4-maleimidophenoxy)phenyl]propane is preferred.

[0042] (Maleimide resin derivatives (AY)) The maleimide resin derivative (AY) is preferably a resin having a structure derived from a maleimide resin having one or more N-substituted maleimide groups (i.e., the above maleimide resin (AX)) and a structure derived from a diamine compound [hereinafter, sometimes referred to as "aminomaleimide resin (A2)" or "component (A2)".]

[0043] [Aminomaleimide resin (A2)] The aminomaleimide resin (A2) has a structure derived from the maleimide resin (AX) and a structure derived from a diamine compound. The structure derived from the maleimide resin (AX) and the structure derived from the diamine compound contained in the aminomaleimide resin (A2) may each be one type alone or two or more types.

[0044] An example of a structure derived from the maleimide resin (AX) is a structure formed by a Michael addition reaction between at least one N-substituted maleimide group among the N-substituted maleimide groups contained in the maleimide resin (AX) and an amino group contained in a diamine compound.

[0045] The content of the structure derived from the maleimide resin (AX) in the aminomaleimide resin (A2) is not particularly limited, but from the viewpoints of dielectric properties and film handling properties, it is preferably 5 to 95 mass %, more preferably 30 to 93 mass %, and even more preferably 60 to 90 mass %.

[0046] An example of a structure derived from a diamine compound is a structure formed by a Michael addition reaction between one or both of the two amino groups contained in the diamine compound and an N-substituted maleimide group contained in the maleimide resin (AX).

[0047] The content of the structure derived from the diamine compound in the aminomaleimide resin (A2) is not particularly limited, but from the viewpoints of dielectric properties, heat resistance, flame retardancy and glass transition temperature, it is preferably 5 to 95 mass%, more preferably 7 to 70 mass%, and even more preferably 10 to 40 mass%.

[0048] The amino group contained in the diamine compound is preferably a primary amino group. As the diamine compound, an aromatic diamine compound having two amino groups directly bonded to an aromatic ring, or a silicone compound having two primary amino groups is preferred.

[0049] Examples of aromatic diamine compounds include 4,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-diethyl-4,4'-diaminodiphenylmethane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 4,4'-[1,3-phenylenebis(1-methylethylidene)]bisaniline, 4,4'-[1,4-phenylenebis(1-methylethylidene)]bisaniline, 3,3'-diethyl-4,4'-diaminodiphenylmethane, etc. Among these, 3,3'-diethyl-4,4'-diaminodiphenylmethane is more preferable from the viewpoint of excellent solubility in organic solvents, reactivity, heat resistance, dielectric properties, low water absorption, etc.

[0050] As the silicone compound having two primary amino groups, a silicone compound having primary amino groups at both ends is preferable, polydimethylsiloxane having primary amino groups at both ends is more preferable, and polydimethylsiloxane having primary amino groups only at both ends is even more preferable. The primary amino group equivalent of the silicone compound having two primary amino groups is not particularly limited, but is preferably 300 to 2,000 g / mol, more preferably 400 to 1,500 g / mol, and even more preferably 500 to 1,000 g / mol.

[0051] The weight average molecular weight (Mw) of the aminomaleimide resin (A2) is not particularly limited, but from the viewpoints of handleability and moldability, it is preferably 400 to 10,000, more preferably 1,000 to 5,000, still more preferably 1,500 to 4,000, and particularly preferably 2,000 to 3,000.

[0052] (Method for producing aminomaleimide resin (A2)) The aminomaleimide resin (A2) can be produced, for example, by reacting the maleimide resin (AX) with a diamine compound in an organic solvent. By reacting the maleimide resin (AX) with a diamine compound, an aminomaleimide resin (A2) is obtained through a Michael addition reaction between the maleimide resin (AX) and the diamine compound. The reaction temperature of the Michael addition reaction is, for example, 50 to 160° C. from the viewpoints of workability such as reaction rate, suppression of gelation of the product during the reaction, etc. The reaction time of the Michael addition reaction is, for example, 0.5 to 10 hours from the viewpoints of productivity and allowing the reaction to proceed sufficiently.

[0053] ((A) Maleimide resin content) In the resin varnish of this embodiment, the content of the (A) maleimide-based resin is not particularly limited, but is preferably 20 to 95 mass%, more preferably 50 to 90 mass%, and even more preferably 70 to 85 mass%, relative to the total amount (100 mass%) of the resin components in the resin varnish of this embodiment. When the content of the maleimide resin (A) is equal to or greater than the lower limit, a cured product having better moldability, heat resistance, and conductor adhesion tends to be obtained. When the content of the maleimide resin (A) is equal to or less than the upper limit, a cured product having better dielectric properties tends to be obtained.

[0054] In this specification, the term "resin component" refers to a resin and a compound that forms a resin through a curing reaction. In the resin varnish of this embodiment, for example, components (A), (B), and (C) correspond to the resin components, while components (D), (E), (F), and (G) are not included in the resin components.

[0055] The content of the resin component in the resin varnish of this embodiment is not particularly limited, but is preferably 10 to 90 mass%, more preferably 20 to 70 mass%, and even more preferably 30 to 50 mass%, relative to the total solid content (100 mass%) of the resin varnish of this embodiment. When the content of the resin component is equal to or more than the lower limit, the moldability of the resin composition obtained by drying the resin varnish tends to be improved. When the content of the resin component is equal to or less than the upper limit, a cured product having excellent low thermal expansion tends to be obtained.

[0056] <(B) Polyphenylene ether resin> The polyphenylene ether resin (B) is not particularly limited as long as it is a resin having a polyphenylene ether chain and a functional group containing an ethylenically unsaturated bond. The resin varnish of the present embodiment, by containing the polyphenylene ether resin (B), tends to easily give a cured product having more excellent dielectric properties. The (B) polyphenylene ether resin may be used alone or in combination of two or more kinds.

[0057] The polyphenylene ether resin (B) has a phenylene ether bond, and preferably has a structural unit represented by the following general formula (B-1).

[0058] [ka] (In the formula, R B1 is a hydrocarbon group having 1 to 5 carbon atoms or a halogen atom. B1 is an integer from 0 to 4.)

[0059] R in the above general formula (B-1) B1 Examples of the hydrocarbon group having 1 to 5 carbon atoms represented by include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, an n-pentyl group, etc. The hydrocarbon group having 1 to 5 carbon atoms may be either a straight chain or a branched chain. The hydrocarbon group having 1 to 5 carbon atoms is preferably a hydrocarbon group having 1 to 3 carbon atoms, and more preferably a methyl group. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0060] In the above general formula (B-1), n B1 is an integer of 0 to 4, preferably 1 or 2, and more preferably 2. B1 If is 1 or 2, R B1 The substitution position of is preferably the ortho position on the benzene ring based on the substitution position of the oxygen atom. B1 If is an integer equal to or greater than 2, multiple R B1 They may be the same or different. The phenylene ether unit represented by the above general formula (B-1) is preferably a phenylene ether unit represented by the following general formula (B-1').

[0061] [ka]

[0062] (B) The polyphenylene ether resin has a functional group containing an ethylenically unsaturated bond (hereinafter, may be referred to as an "ethylenically unsaturated bond-containing group"). In this specification, the term "ethylenically unsaturated bond" means a carbon-carbon double bond capable of undergoing an addition reaction, and does not include a double bond in an aromatic ring.

[0063] Examples of the ethylenically unsaturated bond-containing group include a vinyl group, an allyl group, a 1-methylallyl group, an isopropenyl group, a 2-butenyl group, a 3-butenyl group, a styryl group, a maleimide group, and a group represented by the following general formula (B-2).

[0064] [ka] (In the formula, R B2 is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms.

[0065] R in the above general formula (B-2) B2 The number of carbon atoms in the alkyl group having 1 to 20 carbon atoms represented by R is preferably 1 to 10, more preferably 1 to 3, and even more preferably 1. That is, R B2 More preferably, R is a methyl group. B2 The group represented by the above general formula (B-2) in which R is a hydrogen atom corresponds to an acryloyl group, B2 The group represented by the above general formula (B-2) in which is a methyl group corresponds to a methacryloyl group.

[0066] Among the above, from the viewpoint of dielectric properties, the ethylenically unsaturated bond-containing group possessed by the (B) polyphenylene ether resin is preferably a group represented by the above general formula (B-2), more preferably a (meth)acryloyl group, and even more preferably a methacryloyl group.

[0067] The number of ethylenically unsaturated bond-containing groups that the (B) polyphenylene ether resin has in one molecule is not particularly limited, but is preferably 1 to 5, more preferably 2 to 3, and even more preferably 2. When the number of ethylenically unsaturated bond-containing groups is equal to or greater than the lower limit, a cured product having better heat resistance tends to be obtained. When the number of ethylenically unsaturated bond-containing groups is equal to or less than the upper limit, the flowability and moldability of the resin composition obtained by drying the resin varnish tends to be better.

[0068] The (B) polyphenylene ether resin preferably has an ethylenically unsaturated bond-containing group at a terminal, more preferably at both terminals. The (B) polyphenylene ether resin may have an ethylenically unsaturated bond-containing group in a location other than the terminal end, but it preferably has an ethylenically unsaturated bond-containing group only at the terminal end, and more preferably has an ethylenically unsaturated bond-containing group only at both terminals.

[0069] The weight average molecular weight (Mw) of the (B) polyphenylene ether resin is not particularly limited, but is preferably from 500 to 7,000, more preferably from 800 to 5,000, and even more preferably from 1,000 to 3,000. When the weight average molecular weight (Mw) of the (B) polyphenylene ether resin is equal to or greater than the above lower limit, a cured product having excellent dielectric properties and heat resistance tends to be obtained. When the weight average molecular weight (Mw) of the (B) polyphenylene ether resin is equal to or less than the above upper limit, the moldability of the resin composition obtained by drying the resin varnish tends to be improved.

[0070] The method for synthesizing the polyphenylene ether resin (B) is not particularly limited, and any known method for synthesizing and modifying polyphenylene ether can be used.

[0071] ((B) Polyphenylene ether resin content) The content of the (B) polyphenylene ether resin in the resin varnish of this embodiment is not particularly limited, but is preferably 1 to 30 mass%, more preferably 5 to 25 mass%, and even more preferably 10 to 20 mass%, relative to the total amount (100 mass%) of the resin components in the resin varnish of this embodiment. When the content of the polyphenylene ether resin (B) is equal to or greater than the lower limit, a cured product having excellent dielectric properties tends to be obtained. When the content of the polyphenylene ether resin (B) is equal to or less than the upper limit, the moldability of the resin composition obtained by drying the resin varnish tends to be improved.

[0072] <(C) Styrene-based thermoplastic resin> The (C) styrene-based thermoplastic resin is not particularly limited as long as it is a styrene-based thermoplastic resin having a weight average molecular weight (Mw) of more than 10,000 and less than 100,000. The resin varnish of the present embodiment, by containing the styrene-based thermoplastic resin (C), tends to easily give a cured product having more excellent dielectric properties. The (C) styrene-based thermoplastic resin may be used alone or in combination of two or more kinds.

[0073] (C) Styrenic thermoplastic resin has a structural unit derived from a styrene compound. Examples of the styrene compound include styrene; alkyl-substituted styrene such as α-methylstyrene, o-methylstyrene, m-methylstyrene, and p-methylstyrene. The number of carbon atoms in the alkyl group of the alkyl-substituted styrene is not particularly limited, but is preferably 1 to 5, more preferably 1 to 3, and even more preferably 1 or 2.

[0074] The (C) styrene-based thermoplastic resin may contain structural units other than the structural units derived from the styrene-based compound. Examples of structural units other than the structural units derived from a styrene-based compound that may be contained in the (C) styrene-based thermoplastic resin include a structural unit derived from butadiene, a structural unit derived from isoprene, a structural unit derived from maleic acid, and a structural unit derived from maleic anhydride. The butadiene-derived structural unit and the isoprene-derived structural unit may be hydrogenated. When hydrogenated, the butadiene-derived structural unit is a structural unit having a mixture of ethylene units and butylene units, and the isoprene-derived structural unit is a structural unit having a mixture of ethylene units and propylene units.

[0075] Examples of the (C) styrene-based thermoplastic resin include hydrogenated styrene-butadiene-styrene block copolymers, hydrogenated styrene-isoprene-styrene block copolymers, and styrene-maleic anhydride copolymers. Examples of hydrogenated styrene-butadiene-styrene block copolymers include SEBS obtained by completely hydrogenating the carbon-carbon double bonds in the butadiene block, and SBBS obtained by partially hydrogenating the carbon-carbon double bonds at the 1,2-bond sites in the butadiene block. Hydrogenated styrene-isoprene-styrene block copolymers are obtained as SEPS by hydrogenating the polyisoprene portion. Among these, SEBS and SEPS are preferred, with SEBS being more preferred, from the viewpoints of dielectric properties, adhesion to conductors, heat resistance, glass transition temperature, and low thermal expansion.

[0076] In the (C) styrene-based thermoplastic resin, the content of structural units derived from a styrene-based compound [hereinafter, may be referred to as "styrene content"] is not particularly limited, but from the viewpoints of dielectric characteristics, conductor adhesion, heat resistance, and low thermal expansion, it is preferably 10 to 70 mass%, more preferably 20 to 60 mass%, and even more preferably 40 to 50 mass%.

[0077] The weight average molecular weight (Mw) of the (C) styrene-based thermoplastic resin is more than 10,000 and less than 100,000, preferably 15,000 to 98,000, more preferably 30,000 to 95,000, even more preferably 50,000 to 93,000, still more preferably 70,000 to 92,000, and particularly preferably 80,000 to 90,000. When the weight average molecular weight (Mw) of the (C) styrene-based thermoplastic resin is equal to or greater than the lower limit, the resin composition obtained by drying the resin varnish tends to have better moldability. When the weight average molecular weight (Mw) of the (C) styrene-based thermoplastic resin is equal to or less than the upper limit, the resin composition tends to have excellent compatibility with other resins.

[0078] ((C) Styrenic thermoplastic resin content) The content of the (C) styrene-based thermoplastic resin in the resin varnish of this embodiment is not particularly limited, but is preferably 1 to 30 mass%, more preferably 3 to 20 mass%, and even more preferably 5 to 10 mass%, relative to the total amount (100 mass%) of the resin components in the resin varnish of this embodiment. When the content of the (C) styrene-based thermoplastic resin is equal to or greater than the above lower limit, a cured product having better dielectric properties and flexibility tends to be obtained. When the content of the (C) styrene-based thermoplastic resin is equal to or less than the above upper limit, a cured product having better heat resistance and flame retardancy tends to be obtained.

[0079] <(D)Organic peroxide> (D) The organic peroxide is not particularly limited as long as it is an organic compound containing a peroxide bond (--OO--). The resin varnish of this embodiment contains an organic peroxide (D), so that a resin composition having excellent moldability can be obtained even at a high drying temperature. Although the details of the reason are unclear, one of the reasons is that the organic peroxide (D) in the resin varnish of this embodiment promotes the curing of the resin component at a relatively low temperature, but is easily deactivated at a high temperature, so that the fluidity of the molten resin is maintained to an extent that good moldability can be obtained even when dried at a high temperature. The (D) organic peroxide may be used alone or in combination of two or more kinds.

[0080] The one-hour half-life temperature of the (D) organic peroxide is not particularly limited, but is preferably 100 to 200°C, more preferably 120 to 170°C, and further preferably 130 to 150°C. When the one-hour half-life temperature of the (D) organic peroxide is equal to or higher than the lower limit, the progress of unintended reactions during storage tends to be easily suppressed. Also, when the one-hour half-life temperature of the (D) organic peroxide is equal to or lower than the upper limit, the resin flow of the resin composition obtained by drying the resin varnish tends to be more easily suppressed. The one-hour half-life temperature of the organic peroxide (D) can be calculated by decomposing the organic peroxide (D) in a solvent under a plurality of temperature conditions to obtain the decomposition rate constant at each temperature, and then plotting these decomposition rate constants in an Arrhenius plot. Note that the one-hour half-life temperature in this embodiment is the one-hour half-life temperature measured in benzene under the condition that the concentration of the organic peroxide (D) is 0.1 mol / L.

[0081] (D) Examples of organic peroxides include peroxyketals such as 1,1-di(t-butylperoxy)cyclohexane, 2,2-di(t-butylperoxy)butane, 2,2-di(4,4-di-t-butylperoxycyclohexyl)propane, and 1,1-di(t-amylperoxy)cyclohexane; hydroperoxides such as cumene hydroperoxide and t-butyl hydroperoxide; alkyl peroxides such as t-butyl peroxyacetate and t-amylperoxyisononanoate; t-butyl cumyl peroxide and di-t-butyl Examples of the peroxide include dialkyl peroxides such as tert-butyl peroxide, dicumyl peroxide, di-t-hexyl peroxide, and 1,3-bis(2-t-butylperoxyisopropyl)benzene; peroxy esters such as t-butyl peroxyacetate, t-butyl peroxybenzoate, and t-butylperoxyisopropyl monocarbonate; peroxy carbonates such as t-butylperoxyisopropyl carbonate and polyether tetrakis(t-butylperoxycarbonate); and diacyl peroxides such as dibenzoyl peroxide. Among these, 1,3-bis(2-t-butylperoxyisopropyl)benzene is preferred from the viewpoint of moldability of the resin composition obtained by drying the resin varnish.

[0082] (D) Organic peroxide content The content of the (D) organic peroxide in the resin varnish of this embodiment is not particularly limited, but is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, and even more preferably 0.5 to 2 parts by mass, relative to 100 parts by mass of the (A) maleimide-based resin. When the content of the (D) organic peroxide is within the above range, the moldability of the resin composition obtained by drying the resin varnish tends to be improved.

[0083] <(E) Organic Solvent> The (E) organic solvent may be used alone or in combination of two or more kinds. Examples of (E) organic solvents include alcohol-based solvents such as ethanol, propanol, butanol, methyl cellosolve, butyl cellosolve, propylene glycol monomethyl ether, and propylene glycol monomethyl ether acetate; ketone-based solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ether-based solvents such as tetrahydrofuran; aromatic hydrocarbon-based solvents such as toluene, xylene, and mesitylene; nitrogen-containing solvents such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone; sulfur-containing solvents such as dimethyl sulfoxide; and ester-based solvents such as γ-butyrolactone.

[0084] The boiling point of the (E) organic solvent is not particularly limited, but is preferably 50 to 230° C., more preferably 60 to 180° C., and further preferably 70 to 150° C. In addition, the boiling point of the (E) organic solvent may be 80° C. or higher, 100° C. or higher, 110° C. or higher, 120° C. or higher, 130° C. or higher, or 140° C. or higher, as necessary. When the boiling point of the (E) organic solvent is equal to or higher than the lower limit, the organic solvent is unlikely to volatilize rapidly, the occurrence of foaming, etc. is suppressed, and the appearance of the prepreg obtained from the resin varnish tends to be better. When the boiling point of the (E) organic solvent is equal to or lower than the upper limit, the drying time can be shortened, and the productivity tends to be excellent. In addition, since the resin varnish of this embodiment can obtain a resin composition having excellent moldability even if the drying temperature is increased, it is possible to use an organic solvent with a high boiling point. In addition, the boiling point is a value at normal pressure (1 atmosphere).

[0085] (E) Organic Solvent Content The content of the (E) organic solvent in the resin varnish of this embodiment is not particularly limited, but is preferably 10 to 90 mass%, more preferably 20 to 70 mass%, and even more preferably 30 to 50 mass%, relative to the total amount (100 mass%) of the resin varnish. When the content of the (E) organic solvent is equal to or greater than the lower limit, the resin varnish tends to have better handleability, whereas when the content of the (E) organic solvent is equal to or less than the upper limit, the drying time can be shortened, and the productivity tends to be excellent.

[0086] <(F) Inorganic filler> The resin varnish of the present embodiment preferably further contains (F) an inorganic filler. The resin varnish of the present embodiment, by containing the inorganic filler (F), tends to easily give a cured product having low thermal expansion properties, heat resistance, and flame retardancy. The (F) inorganic filler may be used alone or in combination of two or more kinds.

[0087] (F) Examples of inorganic fillers include silica, alumina, titanium oxide, mica, beryllia, barium titanate, potassium titanate, strontium titanate, calcium titanate, aluminum carbonate, magnesium hydroxide, aluminum hydroxide, aluminum silicate, calcium carbonate, calcium silicate, magnesium silicate, silicon nitride, boron nitride, clay, talc, aluminum borate, and silicon carbide. Among these, silica, alumina, mica, and talc are preferred from the viewpoint of low thermal expansion, heat resistance, and flame retardancy, silica and alumina are more preferred, and silica is even more preferred. As silica, fused silica is preferred from the viewpoint of dispersibility and moldability.

[0088] The average particle size of the (F) inorganic filler is not particularly limited, but from the viewpoint of dispersibility and fine wiring ability of the (F) inorganic filler, it is preferably 0.01 to 20 μm, more preferably 0.1 to 10 μm, even more preferably 0.2 to 1 μm, and particularly preferably 0.3 to 0.8 μm. In this specification, the average particle size of the inorganic filler (F) refers to the particle size at the point corresponding to 50% volume when a cumulative frequency distribution curve of particle sizes is calculated assuming the total volume of the particles to be 100%. The average particle size of the inorganic filler (F) can be measured, for example, by a particle size distribution measuring device using a laser diffraction scattering method. The shape of the (F) inorganic filler may be, for example, spherical or crushed, with spherical being preferred.

[0089] ((F) Inorganic filler content) When the resin varnish of this embodiment contains an inorganic filler (F), the content of the inorganic filler (F) is not particularly limited, but is preferably 30 to 90 mass%, more preferably 40 to 80 mass%, and even more preferably 50 to 70 mass%, relative to the total amount of solids contained in the resin varnish (100 mass%). When the content of the (F) inorganic filler is equal to or more than the lower limit, a cured product having low thermal expansion, heat resistance, and flame retardancy tends to be obtained. When the content of the (F) inorganic filler is equal to or less than the upper limit, the moldability of the resin composition obtained by drying the resin varnish tends to be improved.

[0090] <(G) Curing accelerators other than organic peroxides> From the viewpoint of further accelerating the curing reaction, the resin varnish of the present embodiment preferably further contains (G) a curing accelerator other than the organic peroxide. (G) The curing accelerator other than the organic peroxide may be used alone or in combination of two or more kinds.

[0091] (G) Examples of the curing accelerator other than the organic peroxide include an amine-based curing accelerator, an imidazole-based curing accelerator, a phosphorus-based curing accelerator, an organic metal salt, an acid catalyst, etc. In the present embodiment, the imidazole-based curing accelerator is not classified as an amine-based curing accelerator. Examples of the amine-based curing accelerator include amine compounds having primary to tertiary amines such as triethylamine, pyridine, tributylamine, and dicyandiamide; and quaternary ammonium compounds. Examples of the imidazole-based curing accelerator include imidazole compounds such as methylimidazole, phenylimidazole, and 2-undecylimidazole; and isocyanate mask imidazoles such as an addition reaction product of hexamethylene diisocyanate resin and 2-ethyl-4-methylimidazole. Examples of the phosphorus-based curing accelerator include tertiary phosphines such as triphenylphosphine; and quaternary phosphonium compounds such as an addition reaction product of p-benzoquinone and tri-n-butylphosphine. Examples of the organic metal salt include carboxylates of manganese, cobalt, and zinc. Examples of the acid catalyst include p-toluenesulfonic acid. Among these, from the viewpoints of dielectric properties, heat resistance, conductor adhesion and elastic modulus, amine-based curing accelerators, imidazole-based curing accelerators and phosphorus-based curing accelerators are preferred, dicyandiamide and quaternary phosphonium compounds are more preferred, and it is even more preferred to use these in combination.

[0092] When the resin varnish of this embodiment contains (G) a curing accelerator other than an organic peroxide, the content thereof is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 7 parts by mass, and even more preferably 0.1 to 3 parts by mass, relative to 100 parts by mass of the maleimide resin (A). When the content of the (G) curing accelerator other than the organic peroxide is equal to or more than the lower limit, a sufficient curing acceleration effect tends to be obtained. Also, when the content of the (G) curing accelerator other than the organic peroxide is equal to or less than the upper limit, storage stability tends to be improved.

[0093] <Other ingredients> The resin varnish of the present embodiment may further contain, as necessary, one or more optional components selected from the group consisting of resin materials other than the above components, flame retardants, antioxidants, heat stabilizers, antistatic agents, ultraviolet absorbers, pigments, colorants, lubricants, silane coupling agents, and other additives. Each of the above optional components may be used alone or in combination of two or more. The content of the above-mentioned optional components in the resin varnish of this embodiment is not particularly limited, and may be used as necessary within a range that does not impair the effects of this embodiment, and may not contain the above-mentioned optional components depending on the desired performance.

[0094] <Method of manufacturing resin varnish> The resin varnish of the present embodiment can be produced by mixing the above-mentioned components. When mixing the components, the components may be dissolved or dispersed while being stirred. The order in which the components are mixed, the mixing temperature, the mixing time, and other conditions are not particularly limited and may be set arbitrarily depending on the types of the components to be mixed, etc.

[0095] The resin varnish of the present embodiment is dried to form a resin composition obtained by drying the resin varnish, and a prepreg, a resin film, etc., which will be described later, containing the resin composition. The drying conditions for the resin varnish of this embodiment are preferably determined depending on the type of (E) organic solvent used, etc., but from the viewpoint of moldability and suppression of resin flow, the drying temperature is preferably 120 to 200°C, more preferably 130 to 190°C, even more preferably 140 to 180°C, and particularly preferably 150 to 170°C. The drying time of the resin varnish of the present embodiment is not particularly limited, but may be, for example, 1 to 10 minutes, or 3 to 5 minutes.

[0096] [Resin composition] This embodiment may also provide the following resin composition. (A) one or more selected from the group consisting of maleimide resins having one or more N-substituted maleimide groups and derivatives of the maleimide resins, (B) a polyphenylene ether resin having a functional group containing an ethylenically unsaturated bond; (C) a styrene-based thermoplastic resin having a weight average molecular weight (Mw) of more than 10,000 and less than 100,000; (D) an organic peroxide; A resin composition comprising: That is, the resin composition of this embodiment corresponds to the resin varnish of this embodiment in which the organic solvent (E) is added as an optional component. The preferred aspects of each component in the resin composition of this embodiment are the same as the preferred aspects of each component in the resin varnish of this embodiment.

[0097] [Prepreg manufacturing method] The method for producing a prepreg of the present embodiment is a method for producing a prepreg using the resin varnish of the present embodiment. A method for producing the prepreg of the present embodiment is, for example, a method in which the resin varnish of the present embodiment is impregnated into a sheet-like fiber substrate, and then the substrate is dried by heating. A suitable aspect of the drying conditions for the resin varnish in the manufacturing method for the prepreg of this embodiment is the same as the suitable drying conditions for the resin varnish of this embodiment described above.

[0098] Examples of the material of the sheet-like fiber substrate include inorganic fibers such as E glass, D glass, S glass, and Q glass; organic fibers such as polyimide, polyester, and tetrafluoroethylene; and mixtures thereof. These sheet-like fiber substrates have shapes such as woven fabric, nonwoven fabric, roving, chopped strand mat, and surfacing mat. Among these, glass cloth is preferred as the sheet-like fiber substrate.

[0099] The content of the resin composition in the prepreg of this embodiment is not particularly limited, but from the viewpoint of easily obtaining better moldability, it is preferably 20 to 90 mass%, more preferably 25 to 80 mass%, and even more preferably 30 to 75 mass%.

[0100] [Manufacturing method of resin film] The method for producing a resin film of the present embodiment is a method for producing a resin film using the resin varnish of the present embodiment. The resin film produced by the resin film producing method of the present embodiment is preferably a resin film containing the above-mentioned resin composition of the present embodiment. The method for producing the resin film of this embodiment is, for example, a method in which the resin varnish of this embodiment is applied to a support and then dried by heating.

[0101] Examples of the support include a plastic film, a metal foil, and a release paper. The preferred drying conditions for the resin varnish are the same as the preferred drying conditions for the resin varnish of this embodiment described above.

[0102] [Laminate manufacturing method] The method for producing a laminated board of the present embodiment is a method for producing a laminated board using a prepreg produced by the prepreg producing method of the present embodiment. Incidentally, a laminate having a metal foil is sometimes called a metal-clad laminate.

[0103] The method for producing the laminate of this embodiment is, for example, a method in which metal foil is placed on one or both sides of the prepreg of this embodiment, and then the laminate is heated and pressurized to form it.

[0104] The metal of the metal foil is not particularly limited, and examples thereof include copper, gold, silver, nickel, platinum, molybdenum, ruthenium, aluminum, tungsten, iron, titanium, chromium, and alloys containing one or more of these metal elements.

[0105] When performing the hot and pressure molding, only one prepreg may be used, or two or more prepregs may be laminated and used. For the hot pressure molding, for example, a multi-stage press, a multi-stage vacuum press, a continuous molding machine, an autoclave molding machine, or the like can be used. The conditions for the hot and press molding are not particularly limited, but may be, for example, a temperature of 100 to 300° C., a time of 10 to 300 minutes, and a pressure of 1.5 to 5 MPa.

[0106] [Manufacturing method for printed wiring boards] The method for producing a printed wiring board of this embodiment is a method for producing a printed wiring board using a prepreg produced by the method for producing a prepreg of this embodiment or a resin film produced by the method for producing a resin film of this embodiment.

[0107] The method for producing a printed wiring board of this embodiment is, for example, a method for forming a conductor circuit on a cured product of a prepreg produced by the method for producing a prepreg of this embodiment or a cured product of a resin film produced by the method for producing a resin film of this embodiment by a known method. In addition, a multilayer printed wiring board can be produced by further performing a multilayer adhesive process as necessary. The conductor circuit can be formed, for example, by appropriately performing a hole drilling process, a metal plating process, an etching process of a metal foil, or the like.

[0108] [Semiconductor package manufacturing method] The method for manufacturing a semiconductor package according to the present embodiment is a method for manufacturing a semiconductor package that uses a printed wiring board manufactured by the method for manufacturing a printed wiring board according to the present embodiment. The method for manufacturing a semiconductor package according to this embodiment is, for example, a method for mounting a semiconductor chip, memory, and the like, by a known method, on a printed wiring board manufactured by the method for manufacturing a printed wiring board according to this embodiment. EXAMPLES

[0109] The present embodiment will be specifically described below with reference to examples, although the present embodiment is not limited to the following examples.

[0110] In each example, the weight average molecular weight (Mw) was measured by the following method. The values ​​were calculated from a calibration curve using standard polystyrene by gel permeation chromatography (GPC). The calibration curve was approximated by a third-order equation using standard polystyrene: TSKstandard POLYSTYRENE (Type; A-2500, A-5000, F-1, F-2, F-4, F-10, F-20, F-40) [manufactured by Tosoh Corporation, product name]. The measurement conditions for GPC are shown below. ·Device: Pump: L-6200 type [manufactured by Hitachi High-Technologies Corporation] Detector: L-3300 type RI [Hitachi High-Technologies Corporation] Column oven: L-655A-52 [Hitachi High-Technologies Corporation] Column: Guard column: TSK Guardcolumn HHR-L + column: TSKgel G4000HHR + TSKgel G2000HHR (all manufactured by Tosoh Corporation, product names) Column size: 6.0 x 40 mm (guard column), 7.8 x 300 mm (column) Eluent: Tetrahydrofuran Sample concentration: 30mg / 5mL ·Injection volume: 20μL ·Flow rate: 1.00mL / min ·Measurement temperature: 40℃

[0111] [Production Example 1: Production of aminomaleimide resin] In a 5-liter reaction vessel equipped with a thermometer, a stirrer, and a moisture content meter with a reflux condenser, capable of heating and cooling, 100 parts by mass of 2,2-bis[4-(4-maleimidophenoxy)phenyl]propane, 5.6 parts by mass of a silicone compound (primary amino group equivalent weight 750 g / mol) having primary amino groups at both ends, 7.9 parts by mass of 3,3'-diethyl-4,4'-diaminodiphenylmethane, and 171 parts by mass of propylene glycol monomethyl ether were added and reacted for 2 hours under reflux. This was concentrated at the reflux temperature for 3 hours to produce a solution of aminomaleimide resin with a solid content concentration of 65% by mass. The weight average molecular weight (Mw) of the obtained aminomaleimide resin was about 2,700.

[0112] Examples 1 to 3, Comparative Examples 1 to 4 (Production of resin composition) The solids and organic solvents shown in Table 1 were blended according to the blending composition shown in Table 1, and stirred and mixed at room temperature (25°C) to produce a resin varnish with a solids concentration of 63 mass% (content of (E) organic solvent: 37 mass%). Note that in Table 1, the unit of the blending amount of solids is parts by mass, and in the case of a solution, it means parts by mass converted into solids.

[0113] (Prepreg manufacturing) The resin varnish obtained above was impregnated into a glass cloth having a thickness of 0.02 mm, and then dried for 3 to 5 minutes at a temperature shown in Table 1 to prepare a prepreg having a resin composition content of 70 mass %.

[0114] (Manufacturing double-sided copper-clad laminates) Copper foil with a thickness of 12 μm (manufactured by Mitsui Kinzoku Co., Ltd., product name "3EC-M3-VLP-12", Rz of M side: 3.0 μm) was placed on the top and bottom of one of the prepregs obtained above, with the M side in contact with the prepreg, and heated and pressurized for 90 minutes at a temperature of 230°C, a pressure of 3.0 MPa, and a time of 90 minutes to produce a double-sided copper-clad laminate (thickness: 0.04 mm).

[0115] [Evaluation method] The evaluations were carried out according to the following methods, and the results are shown in Table 1.

[0116] (Method of evaluating prepreg moldability) A circuit board (size in plan view: 500 mm x 500 mm) having circuits (12 μm thick, multiple rectangular areas of 70 mm x 115 mm formed in a lattice pattern by multiple vertical and horizontal slits (slit width 2 mm), the multiple rectangular areas including rectangular areas having a comb-shaped pattern with a residual copper ratio of 15, 20, 25, 30, 35, 40, or 45 volume % and rectangular areas having a pattern with dot-shaped openings with a residual copper ratio of 50, 55, 60, 65, 70, 75, 80, 85, or 90 volume %) on both sides was prepared, and the prepreg and copper foil obtained above were placed on both sides of the circuit board, in that order, and press molding was performed under the following conditions. <Press molding conditions> ·Heating temperature (maximum temperature reached): 230℃ Press pressure: 3MPa Pressing time: 3 hours After press molding, the copper foil on both sides was removed by etching, and the area near the circuit was observed visually and with a fluorescent microscope, and the moldability of the prepreg was evaluated according to the following criteria. A: There are no unfilled circuit patterns or slits. B: There are no parts of the circuit pattern that are not filled, but there are parts of the slits that are not filled. C: There are areas that are not filled in both the circuit pattern and the slits.

[0117] (Method for measuring minimum melt viscosity) Approximately 0.6 g of resin powder in a B-stage state was collected by kneading the prepreg produced in each example, and was weighed out and molded into a disk-shaped tablet with a diameter of 20 mm using a tablet molder. The tablet was used as a measurement sample, and the melt viscosity was measured using a rheometer (manufactured by Rheometrics, product name "ARES-2K STD-FCO-STD") under conditions of a heating rate of 3°C / min, a load of 0.2 N, and a temperature range of 50 to 200°C, and the minimum melt viscosity was obtained.

[0118] (Method for evaluating resin flow in prepregs) The resin flow of the prepreg was evaluated by the following method in accordance with IPC TM-650. The prepreg was cut into a 102 mm square, and four pieces were stacked to prepare a test piece, and the weight of the test piece was measured. The measured weight was designated as W1. Next, the test piece was placed in a press machine set at a temperature of 171±3°C, a pressure of 1.38±0.07MPa, and a time of 5±0.5 minutes, and pressed. After that, a disk with a diameter of 81.1 mm was punched out from the center of the test piece, and the weight was measured. The measured weight was designated as W2. Using W1 and W2 obtained above, the resin flow was calculated according to the following formula. Resin flow (%) = {[W1-2×W2] / W1}×100

[0119] [Table 1]

[0120] The details of each material in Table 1 are as follows: [Component (A)] Maleimide resin: Aminomaleimide resin obtained in Production Example 1

[0121] [(B) Component] Polyphenylene ether resin with methacryloyl groups: Polyphenylene ether with methacryloyl groups at both ends (weight average molecular weight (Mw) 1,700)

[0122] [(C) component] SEBS: Maleic anhydride modified hydrogenated styrene thermoplastic resin (SEBS), acid value 10mgCH3ONa / g, styrene content 45% by mass, weight average molecular weight (Mw) 86,000

[0123] [(D) component] 1,3-bis(2-t-butylperoxyisopropyl)benzene (1-hour half-life temperature 137.7℃)

[0124] [(E) component] Toluene: boiling point 110.6℃ Propylene glycol monoethyl ether: boiling point 133℃ Methyl ethyl ketone: boiling point 79.6℃ Methyl isobutyl ketone: boiling point 116℃ Propylene glycol monomethyl ether acetate: boiling point 146°C

[0125] [Component (F)] Silica: Spherical fused silica with an average particle size of 0.5 μm

[0126] [(G) component] p-Benzoquinone and tri-n-butylphosphine adduct Dicyandiamide

[0127] From the results shown in Table 1, it can be seen that the prepregs formed from the resin varnishes of Examples 1 to 3 of this embodiment have better moldability than the resin varnishes of Comparative Examples 1 to 4 that do not contain (D) organic peroxide. Furthermore, from Examples 1 and 2, it can be seen that the resin varnish of this embodiment can suppress resin flow while maintaining good moldability of the prepreg by increasing the drying temperature. Furthermore, from Example 2, it can be seen that the resin varnish of this embodiment can use an organic solvent with a high boiling point.

Claims

1. (A) one or more selected from the group consisting of maleimide resins having one or more N-substituted maleimide groups and derivatives of the maleimide resins; (B) a polyphenylene ether resin having a functional group containing an ethylenically unsaturated bond; (C) a styrene-based thermoplastic resin having a weight average molecular weight (Mw) of more than 10,000 and less than 100,000; (D) an organic peroxide; (E) an organic solvent; A resin varnish containing

2. The resin varnish according to claim 1, wherein the content of the component (D) is 0.01 to 10 parts by mass per 100 parts by mass of the component (A).

3. The resin varnish according to claim 1 or 2, wherein the one-hour half-life temperature of the component (D) is 100 to 200° C.

4. The resin varnish according to claim 1 or 2, wherein the component (B) has a functional group containing an ethylenically unsaturated bond at a terminal thereof.

5. The resin varnish according to claim 1 or 2, wherein the functional group containing an ethylenically unsaturated bond contained in the component (B) is a (meth)acryloyl group.

6. The resin varnish according to claim 1 or 2, further comprising (F) an inorganic filler.

7. The resin varnish according to claim 1 or 2, further comprising (G) a curing accelerator other than an organic peroxide.

8. A method for producing a prepreg using the resin varnish according to claim 1.

9. A method for producing a resin film, using the resin varnish according to claim 1.

10. A method for producing a laminate using a prepreg produced by the method for producing a prepreg according to claim 8.

11. A method for producing a printed wiring board, which uses a prepreg produced by the method for producing a prepreg according to claim 8 or a resin film produced by the method for producing a resin film according to claim 9.

12. A method for manufacturing a semiconductor package, which uses a printed wiring board manufactured by the method for manufacturing a printed wiring board according to claim 11.

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