JP7714950B2 - Polyester resin manufacturing method - Google Patents

Description

The present invention relates to a method for producing a polyester resin. It also relates to a resin crosslinking agent, a resin composition, a sheet-like laminate material, a printed wiring board, a semiconductor chip package, and a semiconductor device obtained using the polyester resin produced by this method.

Resin compositions containing cross-linkable resins such as epoxy resins and their cross-linking agents (curing agents) produce cured products with excellent insulation, heat resistance, and adhesion, and have therefore been widely used as materials for electronic components such as semiconductors and printed wiring boards.

On the other hand, with high-speed communications such as fifth-generation mobile communications systems (5G), transmission loss becomes an issue when operating in high-frequency environments. This necessitates insulating materials with excellent dielectric properties (low dielectric constant, low dielectric dissipation factor). Patent documents 1 and 2, for example, disclose resin compositions containing activated ester resins as insulating materials that achieve good dielectric properties.

Japanese Patent Application Laid-Open No. 2004-075885 JP 2009-235165 A

Activated ester resins are aromatic polyester resins that inherently have poor solubility in organic solvents. Aromatic polyester resins are typically produced by condensation reaction of an acid halide compound with an aromatic hydroxy compound using a hydrophobic organic solvent as the reaction solvent, but the resulting aromatic polyester resins often have poor solubility in the reaction solvent. Among these, rigid-skeleton activated ester resins, which offer an excellent balance of dielectric properties and heat resistance, have particularly poor solubility in the reaction solvent.

Furthermore, this condensation reaction uses a dehydrohalogenating agent such as an alkali or amine, which generates a large amount of by-product salt during the reaction. To remove this by-product salt from the reaction system, water must be added and the reaction mixture must be washed and purified. However, using a reaction solvent with low solubility can lead to serious problems, such as poor oil-water separation, loss of the liquid-liquid interface, or the formation of a large amount of an intermediate emulsion layer.

On the other hand, aromatic solvents such as toluene and xylene, which are typical hydrophobic organic solvents used as reaction solvents, and ketone solvents such as methyl isobutyl ketone (MIBK) are becoming increasingly regulated from a safety perspective, making their use difficult.

Furthermore, resin compositions containing active ester resins are often processed into films or coatings to create thinner films, but this requires the addition of an organic solvent to prepare a varnish-like resin composition. Such organic solvents must also be safer and have high solubility.

The present invention provides a polyester resin production technology, particularly a rigid-skeleton activated ester resin, that can improve problems in the oil-water separation process and uses a safer reaction solvent, as well as a technology for producing a resin composition containing the polyester resin.

As a result of extensive research to solve the above-mentioned problems, the inventors have discovered that by using a solvent selected from the group consisting of cycloalkyl alkyl ethers and alkyltetrahydropyrans as a reaction solvent, problems in the manufacturing process can be significantly improved and a method for manufacturing polyester resins with high consideration given to safety can be provided. Furthermore, the inventors have discovered that the above-mentioned specific solvents are also useful as organic solvents when manufacturing varnish-like resin compositions, leading to the completion of the present invention.

That is, the present invention includes the following.
[1] A method for producing a polyester resin, wherein one or more solvents A selected from the group consisting of cycloalkyl alkyl ethers and alkyltetrahydropyrans are used as a reaction solvent in a condensation reaction between an acid halide compound and an aromatic hydroxy compound.
[2] The method for producing a polyester resin according to [1], wherein the polyester resin contains an active ester group.
[3] The method for producing a polyester resin according to [1] or [2], wherein the acid halide compound is divalent and the aromatic hydroxy compound is a mixture of monovalent and divalent aromatic hydroxy compounds.
[4] The method for producing a polyester resin according to [1] or [2], wherein the acid halide compound is a mixture of monovalent and divalent compounds, and the aromatic hydroxy compound is divalent.
[5] The method for producing a polyester resin according to any one of [1] to [4], wherein the molar ratio of halide groups to aromatic hydroxy groups is in the range of 1.00:0.80 to 1.00:1.20.
[6] The method for producing a polyester resin according to any one of [1] to [5], wherein the polyester resin contains an average of 2 to 10 active ester groups per molecule.
[7] The method for producing a polyester resin according to any one of [1] to [6], wherein the boiling point of the solvent A is in the range of 70 to 150°C.
[8] The method for producing a polyester resin according to any one of [1] to [7], wherein the cycloalkyl alkyl ether is represented by the following formula (1), and the alkyl tetrahydropyran is represented by the following formula (2):
(In the formula,
R ¹¹ represents a cycloalkyl group having 3 to 10 carbon atoms;
^R12 represents an alkyl group having 1 to 6 carbon atoms.
(In the formula,
^R21 represents an alkyl group having 1 to 6 carbon atoms.
[9] The method for producing a polyester resin according to any one of [1] to [8], wherein solvent A contains cyclopentyl methyl ether, cyclohexyl methyl ether, or 4-methyltetrahydropyran.
[10] The method for producing a polyester resin according to any one of [1] to [9], wherein the amount of solvent A added is 30 to 500% by mass relative to 100% by mass of the total amount of the acid halide compound and the aromatic hydroxy compound.
[11] The following steps (1) to (4):
(1) a step of dissolving an acid halide compound and an aromatic hydroxy compound in one or more solvents A selected from the group consisting of cycloalkyl alkyl ethers and alkyltetrahydropyrans to obtain a solution;
(2) adding a dehydrohalogenating agent to the solution to carry out a condensation reaction;
(3) After the condensation reaction, water is added to separate the oil and water, thereby discharging the by-product salt from the system; and (4) further purifying the product by washing with water and separating the oil and water. [10] The method for producing a polyester resin according to any one of [1] to [10], further comprising the steps of:
[12] The following steps (5) and (6):
The method for producing a polyester resin according to [11], further comprising: (5) a step of dehydrating the mixture to precipitate a by-product salt; and (6) a step of removing the by-product salt by filtration.
[13] A resin crosslinking agent comprising (A) a polyester resin and (B) one or more solvents selected from the group consisting of cycloalkyl alkyl ethers and alkyl tetrahydropyrans.
[14] A resin crosslinking agent comprising a polyester resin obtained by the production method according to any one of [1] to [12] and solvent A used as a reaction solvent.
[15] A resin composition comprising (A) a polyester resin, (B) one or more solvents selected from the group consisting of cycloalkyl alkyl ethers and alkyltetrahydropyrans, and (C) a crosslinkable resin.
[16] A resin composition comprising a polyester resin obtained by the production method according to any one of [1] to [12], solvent A used as a reaction solvent, and a crosslinkable resin.
[17] The resin composition according to [15] or [16], further containing an inorganic filler.
[18] The resin composition according to any one of [15] to [17], which is for use in an insulating layer of a printed wiring board.
[19] The resin composition according to any one of [15] to [17], which is for semiconductor encapsulation.
[20] A sheet-like laminate material comprising the resin composition according to any one of [15] to [19].
[21] A printed wiring board comprising an insulating layer made of a cured product of the resin composition according to any one of [15] to [18].
[22] A semiconductor chip package comprising an encapsulating layer made of a cured product of the resin composition according to any one of [15] to [17] and [19].
[23] The semiconductor chip package according to [22], which is a fan-out type package.
[24] A semiconductor device comprising the printed wiring board according to [21] or the semiconductor chip package according to [22] or [23].

The present invention can improve problems that occur during the oil-water separation process when producing polyester resins, particularly rigid-skeleton activated ester resins, and also provides a polyester resin production technology that uses a highly safe reaction solvent, as well as a resin composition production technology that contains the polyester resin.

The present invention will now be described in detail with reference to preferred embodiments. However, the present invention is not limited to the following embodiments and examples, and can be modified and implemented as desired without departing from the scope of the claims of the present invention and their equivalents.

[Method of producing polyester resin]
The method for producing a polyester resin of the present invention (hereinafter also simply referred to as the "production method of the present invention") is characterized in that one or more solvents A selected from the group consisting of cycloalkyl alkyl ethers and alkyltetrahydropyrans are used as reaction solvents in the condensation reaction of an acid halide compound and an aromatic hydroxy compound.

As mentioned above, aromatic polyester resins such as activated ester resins inherently have poor solubility in organic solvents, which can lead to serious problems during oil-water separation in the manufacturing process, such as the disappearance of the liquid-liquid interface and the formation of a large amount of an intermediate emulsion layer. In particular, rigid-skeleton activated ester resins with aromatic polycyclic skeletons have particularly low solubility in reaction solvents, which tends to make problems during the manufacturing process more pronounced.

In contrast, the production method of the present invention, which uses solvent A as the reaction solvent, can significantly improve problems during the production process, even when producing a rigid-skeleton activated ester resin. Combined with the fact that solvent A is safer than toluene, MIBK, and other reaction solvents that have been commonly used up to now, the present invention significantly improves problems during the production process while also providing a polyester resin production technology that takes safety into consideration.

-Solvent A-
Solvent A is at least one selected from the group consisting of cycloalkyl alkyl ethers and alkyl tetrahydropyrans.

The boiling point of solvent A is preferably 150°C or lower, more preferably 140°C or lower, from the viewpoint of facilitating the distillation removal of solvent A after the production of the polyester resin. The lower limit of the boiling point is not particularly limited, but is preferably 70°C or higher, more preferably 80°C or higher, 90°C or higher, or 100°C or higher, from the viewpoint of avoiding extreme volatilization, for example, when solvent A is used as a solvent for producing a varnish-like resin composition containing a polyester resin. Therefore, in one embodiment, the boiling point of solvent A is in the range of 70 to 150°C.

The cycloalkyl alkyl ether used as solvent A is preferably represented by the following formula (1):

(In the formula,
R ¹¹ represents a cycloalkyl group having 3 to 10 carbon atoms;
^R12 represents an alkyl group having 1 to 6 carbon atoms.

In formula (1), R ¹¹ represents a cycloalkyl group having 3 to 10 carbon atoms. The number of carbon atoms in the cycloalkyl group is more preferably 4 or more, and even more preferably 5 or more, and the upper limit is more preferably 8 or less, and even more preferably 7 or less or 6 or less.

In formula (1), R ¹² represents an alkyl group having 1 to 6 carbon atoms. The number of carbon atoms in the alkyl group is more preferably 4 or less, and even more preferably 3 or less.

Among these, from the viewpoint of significantly improving defects in the production process even when producing a rigid skeleton-based activated ester resin, the cycloalkyl alkyl ether represented by formula (1) is preferably cyclopentyl C _1-3 alkyl ether or cyclohexyl C _1-3 alkyl ether, and particularly preferably cyclopentyl methyl ether or cyclohexyl methyl ether.

The alkyltetrahydropyran used as solvent A is preferably represented by the following formula (2):

(In the formula,
^R21 represents an alkyl group having 1 to 6 carbon atoms.

In formula (2), R ²¹ represents an alkyl group having 1 to 6 carbon atoms. The number of carbon atoms in the alkyl group is more preferably 4 or less, and even more preferably 3 or less.

In formula (2), the bonding position of the alkyl group represented by R ²¹ is not particularly limited, and may be any of the 2-position, 3-position, and 4-position.

Among these, from the viewpoint of significantly improving defects in the production process even when producing a rigid skeleton-type active ester resin, the alkyltetrahydropyran represented by formula (2) is preferably a 4-C _1-3 alkyltetrahydropyran, and particularly preferably 4-methyltetrahydropyran.

In a preferred embodiment, solvent A comprises cyclopentyl methyl ether, cyclohexyl methyl ether, or 4-methyltetrahydropyran.

In the production method of the present invention, the concentration of solvent A in the reaction solvent is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 80% by mass or more, still more preferably 90% by mass or more or 95% by mass or more, from the viewpoint of improving defects in the production process, and may even be 100% by mass (solvent A being the only reaction solvent).

- Condensation reaction of acid halide compounds and aromatic hydroxy compounds -
In the production method of the present invention, the polyester resin is produced by a condensation reaction (esterification reaction) between an acid halide compound and an aromatic hydroxy compound.

The manufacturing method of the present invention, which uses the above-mentioned solvent A as the reaction solvent, makes it possible to achieve good oil-water separability during the manufacturing process, specifically the oil-water separation process, regardless of the type of polyester resin. From the perspective of better enjoying the benefits of the present invention, the polyester resin to be manufactured is preferably an activated ester resin, i.e., a polyester resin containing activated ester groups, which tend to cause problems during the oil-water separation process. In the present invention, "activated ester group" refers to an ester bond having an aromatic carbon-C(=O)-O-aromatic carbon structure, and also includes an ester bond having an aliphatic carbon-C(=O)-O-aromatic carbon structure, so long as it exhibits the crosslinking properties of the crosslinkable resin. Therefore, in a preferred embodiment, the polyester resin contains activated ester groups.

In the manufacturing method of the present invention, the polyester resin produced preferably contains an average of 2 to 10 active ester groups per molecule, in order to fully demonstrate the crosslinking properties of the crosslinkable resin.

As mentioned above, among activated ester resins, rigid-skeleton activated ester resins having an aromatic polycyclic skeleton tend to have more pronounced defects during the manufacturing process. In this regard, the manufacturing method of the present invention, which uses solvent A as the reaction solvent, can significantly improve the defects during the manufacturing process, even when producing rigid-skeleton activated ester resins having an aromatic polycyclic skeleton. An aromatic polycyclic skeleton refers to a skeleton containing two or more cyclic structures, at least one of which is an aromatic ring, and the two or more cyclic structures may or may not be fused. The aromatic polycyclic skeleton may be any conventionally known aromatic polycyclic skeleton that constitutes a rigid skeleton-based activated ester resin, including, for example, aromatic hydrocarbon skeletons in which aromatic rings are fused, such as naphthalene skeletons and anthracene skeletons; aromatic hydrocarbon skeletons in which two or more aromatic rings are contained without condensation, such as biphenyl skeletons in which two or more aromatic rings are bonded by single bonds (non-condensed aromatic hydrocarbon skeletons); and aromatic hydrocarbon skeletons in which an aromatic ring is fused with a five-membered ring compound, such as an indane skeleton including a 1,1,3-trimethylindane skeleton and a fluorene skeleton. Therefore, in a preferred embodiment, the polyester resin is an activated ester resin having an aromatic polycyclic skeleton.

In the production method of the present invention, any type of acid halide compound and aromatic hydroxy compound may be used as long as a polyester resin can be produced by their condensation reaction. The acid halide compound is not particularly limited as long as it contains at least a divalent or higher acid halide compound. Depending on the structure of the desired polyester resin, only a divalent or higher acid halide compound may be used, or a mixture of a monovalent acid halide compound and a divalent or higher acid halide compound may be used. Similarly, the aromatic hydroxy compound is not particularly limited as long as it contains at least a divalent or higher aromatic hydroxy compound. Depending on the structure of the desired polyester resin, only a divalent or higher aromatic hydroxy compound may be used, or a mixture of a monovalent aromatic hydroxy compound and a divalent or higher aromatic hydroxy compound may be used.

In a preferred embodiment, a divalent acid halide compound is used as the acid halide compound, and a mixture of a monovalent aromatic hydroxy compound and a divalent aromatic hydroxy compound is used as the aromatic hydroxy compound. That is, the acid halide compound is divalent, and the aromatic hydroxy compound is a mixture of monovalent and divalent aromatic hydroxy compounds. Such an embodiment tends to result in a polyester resin whose terminal structure is derived from a monovalent aromatic hydroxy compound.

In another preferred embodiment, a mixture of monovalent acid halide compounds and divalent acid halide compounds is used as the acid halide compound, and a divalent aromatic hydroxy compound is used as the aromatic hydroxy compound. That is, the acid halide compound is a mixture of monovalent and divalent compounds, and the aromatic hydroxy compound is divalent. Such an embodiment tends to result in a polyester resin whose terminal structure is derived from a monovalent acid halide compound.

Examples of acid halide compounds and aromatic hydroxy compounds that can be suitably used in the production method of the present invention are shown below. As described above, according to the production method of the present invention, which uses solvent A as the reaction solvent, defects in the production process can be significantly improved even when a rigid-skeleton activated ester resin is produced using an acid halide compound having an aromatic polycyclic skeleton (when R ^a1 in the following formula (3) contains an aromatic polycyclic skeleton) or an aromatic hydroxy compound having an aromatic polycyclic skeleton (when the R ^b1 -[L-R ^b1 ] _n moiety in the following formula (5) contains an aromatic polycyclic skeleton).

--Acid halide compounds--
The divalent acid halide compound is preferably a compound represented by the following formula (3).

(In the formula,
R ^a1 represents a divalent aromatic group or a divalent aliphatic group;
Z represents a halogen atom.

The divalent aromatic group represented by R ^a1 is preferably an arylene group which may have a substituent. The arylene group for R ^a1 preferably has 6 to 18 carbon atoms, more preferably 6 to 14, and even more preferably 6 to 10. The number of carbon atoms does not include the number of carbon atoms of the substituent. In a preferred embodiment, the divalent aromatic group represented by R ^a1 is a phenylene group which may have a substituent, or a naphthylene group which may have a substituent, and more preferably a phenylene group which may have a substituent. Furthermore, the substituent which the arylene group for R ^a1 may have is preferably one or more selected from a halogen atom, an alkyl group, and an aryl group, and more preferably one or more selected from a fluorine atom, an alkyl group having 1 to 6 carbon atoms, and an aryl group having 6 to 10 carbon atoms.

The divalent aliphatic group represented by R ^a1 is preferably an alkylene group which may have a substituent, or an alkenylene group which may have a substituent. The alkylene group or alkenylene group in R ^a1 may be either linear or branched. The divalent aliphatic group represented by R ^a1 has preferably 4 or more carbon atoms, more preferably 6 or more or 8 or more carbon atoms. The upper limit is not particularly limited, but may usually be 30 or less, 20 or less, 18 or less, etc. This number of carbon atoms does not include the number of carbon atoms of the substituent. Furthermore, the substituent that the alkylene group or alkenylene group in R ^a1 may have is preferably one or more selected from a halogen atom, an alkyl group, and an aryl group, and more preferably one or more selected from a fluorine atom, an alkyl group having 1 to 6 carbon atoms, and an aryl group having 6 to 10 carbon atoms.

Examples of halogen atoms represented by Z include fluorine, chlorine, bromine, and iodine atoms, with chlorine atoms being preferred.

As mentioned above, the divalent acid halide compound may be appropriately selected depending on the structure of the desired polyester resin. Specific examples of suitable divalent acid halide compounds include optionally substituted isophthalic acid chloride, optionally substituted terephthalic acid chloride, optionally substituted suberic acid chloride, and optionally substituted sebacic acid chloride.

Preferably, the monovalent acid halide compound is a compound represented by the following formula (4):

(In the formula,
R ^a2 represents a monovalent aromatic group or a monovalent aliphatic group;
Z is as described above.)

The monovalent aromatic group represented by R ^a2 is preferably an aryl group which may have a substituent. The aryl group for R ^a2 preferably has 6 to 18 carbon atoms, more preferably 6 to 14, and even more preferably 6 to 10. The number of carbon atoms in the substituent is not included in this number of carbon atoms. In a preferred embodiment, the monovalent aromatic group represented by R ^a2 is an optionally substituted phenyl group or an optionally substituted naphthyl group. Furthermore, the substituent that the aryl group for R ^a2 may have is preferably one or more selected from a halogen atom, an alkyl group, and an aryl group, and more preferably one or more selected from a fluorine atom, an alkyl group having 1 to 6 carbon atoms, and an aryl group having 6 to 10 carbon atoms.

The monovalent aliphatic group represented by R ^a2 is preferably an alkyl group which may have a substituent, or an alkenyl group which may have a substituent. The alkyl group or alkenyl group in R ^a2 may be either linear or branched. The divalent aliphatic group represented by R ^a2 preferably has 4 or more carbon atoms, more preferably 6 or more or 8 or more carbon atoms. The upper limit is not particularly limited, but may usually be 30 or less, 20 or less, 18 or less, etc. Furthermore, the substituent that the alkyl group or alkenyl group in R ^a2 may have is preferably one or more selected from a halogen atom, an alkyl group, and an aryl group, and more preferably one or more selected from a fluorine atom, an alkyl group having 1 to 6 carbon atoms, and an aryl group having 6 to 10 carbon atoms.

As mentioned above, the monovalent acid halide compound may be appropriately selected depending on the structure of the desired polyester resin. Specific examples of suitable monovalent acid halide compounds include optionally substituted benzenecarboxylic acid chloride, optionally substituted naphthalenecarboxylic acid chloride, optionally substituted caproic acid chloride, optionally substituted enanthic acid chloride, and optionally substituted caprylic acid chloride.

--Aromatic hydroxy compounds--
The divalent aromatic hydroxy compound is preferably a compound represented by the following formula (5).

(In the formula,
R ^b1 each independently represents a divalent aromatic group;
L each independently represents a single bond or a divalent linking group;
n represents an integer of 0 to 5.

The divalent aromatic group represented by R ^b1 is preferably an arylene group which may have a substituent. The number of carbon atoms in the arylene group in ^{R b1} is preferably 6 to 18, more preferably 6 to 14, and even more preferably 6 to 10. The number of carbon atoms does not include the number of carbon atoms of the substituent. In a preferred embodiment, the divalent aromatic group represented by R ^b1 is a phenylene group which may have a substituent or a naphthylene group which may have a substituent, and more preferably a phenylene group which may have a substituent. Furthermore, the substituent which the arylene group in R ^b1 may have is preferably one or more selected from a halogen atom, an alkyl group, an aryl group, and an arylalkyl group, and more preferably one or more selected from a fluorine atom, an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 10 carbon atoms, and an arylalkyl group (the aryl group having 6 to 10 carbon atoms and the alkyl group having 1 to 6 carbon atoms). The arylene group in R ^b1 may have a hydroxy group as a substituent. In such a case, the valence of the aromatic hydroxy compound represented by formula (5) may be more than two.

L represents a single bond or a divalent linking group. Examples of divalent linking groups represented by L include divalent organic groups consisting of one or more (e.g., 1 to 3,000, 1 to 1,000, 1 to 100, or 1 to 50) skeletal atoms selected from carbon atoms, oxygen atoms, nitrogen atoms, and sulfur atoms. Among these, divalent aliphatic groups which may have a substituent, or divalent aromatic groups which may have a substituent, are preferred.

Examples of the divalent aliphatic group for L include alkylene groups, cycloalkylene groups, alkenylene groups, cycloalkenylene groups, and alkapolyenylene groups (the number of double bonds is preferably 2 to 10, more preferably 2 to 6, even more preferably 2 to 4, and even more preferably 2). Alkylene groups, cycloalkylene groups, alkenylene groups, and cycloalkenylene groups are preferred, alkylene groups and cycloalkylene groups are more preferred, and cycloalkylene groups are even more preferred. The number of carbon atoms in the divalent aliphatic group for L is not particularly limited. For example, when the divalent aliphatic group is a cycloalkylene group, the number of carbon atoms is preferably 3 to 15, more preferably 3 to 12, and even more preferably 3 to 10. This number of carbon atoms does not include the number of carbon atoms of substituents.

Examples of the divalent aromatic group for L include an arylene group and a heteroarylene group, with an arylene group being preferred. The arylene group for L preferably has 6 to 24 carbon atoms, more preferably 6 to 18, and even more preferably 6 to 14. This number of carbon atoms does not include the number of carbon atoms of the substituents. Examples of arylene groups include a phenylene group, a naphthylene group, an anthracenylene group, a fluorenediyl group (e.g., a 9H-fluorene-9,9-diyl group), a phenanthrenediyl group, an indanediyl group, and a pyrenediyl group. The heteroarylene group for L preferably has 3 to 21 carbon atoms, more preferably 3 to 15, and even more preferably 3 to 9. This number of carbon atoms does not include the number of carbon atoms of the substituents. Examples of heteroarylene groups include a pyrrolediyl group, a furandiyl group, a thiophenediyl group, a pyridinediyl group, a pyridazinediyl group, a pyrimidinediyl group, a pyrazinediyl group, and a triazinediyl group.

The substituents that the divalent group represented by L may have are preferably one or more selected from a halogen atom, an alkyl group, and an aryl group, and more preferably one or more selected from a fluorine atom, an alkyl group having 1 to 6 carbon atoms, and an aryl group having 6 to 10 carbon atoms.

n is an integer from 0 to 5, preferably from 0 to 3, and more preferably from 0 to 2.

As mentioned above, the divalent aromatic hydroxy compound may be appropriately selected depending on the structure of the desired polyester resin. Examples of divalent aromatic hydroxy compounds include polyaddition products of phenols with unsaturated aliphatic cyclic compounds containing two double bonds per molecule, where n is 1 or greater, and various bisphenol compounds. Examples of polyaddition products of unsaturated aliphatic cyclic compounds with phenols include polyaddition products of unsaturated aliphatic cyclic compounds such as dicyclopentadiene, tetrahydroindene, norbornadiene, limonene, and vinylcyclohexene with optionally substituted phenols (e.g., phenol, cresol, xylenol, ethylphenol, propylphenol, vinylphenol, allylphenol, phenylphenol, benzylphenol, and halophenols). Specific examples include dicyclopentadiene-phenol polyaddition products. Examples of bisphenol compounds include bisphenol fluorene, bisphenol A, bisphenol F, bisphenol AF, bisphenol AP, bisphenol B, bisphenol BP, bisphenol C, and bisphenol M. Components where n is 0 include diols (such as benzenediol and naphthalenediol) in which two hydroxy groups are bonded to carbon atoms on an aromatic ring.

Preferably, the monovalent aromatic hydroxy compound is a compound represented by the following formula (6):

(In the formula,
R ^b2 represents a monovalent aromatic group.

The monovalent aromatic group represented by R ^b2 is preferably an aryl group which may have a substituent. The aryl group for R ^a2 preferably has 6 to 18 carbon atoms, more preferably 6 to 14, and even more preferably 6 to 10. The number of carbon atoms in the substituent is not included in this number of carbon atoms. In a preferred embodiment, the monovalent aromatic group represented by R ^a2 is an optionally substituted phenyl group or an optionally substituted naphthyl group. Furthermore, the substituent that the aryl group for R ^a2 may have is preferably one or more selected from a halogen atom, an alkyl group, and an aryl group, and more preferably one or more selected from a fluorine atom, an alkyl group having 1 to 6 carbon atoms, and an aryl group having 6 to 10 carbon atoms.

As mentioned above, the monovalent aromatic hydroxy compound may be appropriately selected depending on the structure of the desired polyester resin. Examples of monovalent aromatic hydroxy compounds include naphthol, which may have a substituent, and phenol, which may have a substituent.

In the production method of the present invention, the acid halide compound and aromatic hydroxy compound are preferably used in a quantitative ratio such that the molar ratio of halide groups to aromatic hydroxy groups (former:latter) is in the range of 1.00:0.80 to 1.00:1.20, and more preferably in the range of 1.00:0.90 to 1.00:1.10.

Furthermore, when a mixture of monovalent and divalent acid halide compounds is used, the quantitative ratio of the monovalent compound to the divalent compound may be determined appropriately depending on the structure of the desired polyester resin. For example, it is preferable to use a quantitative ratio such that the molar ratio of halide groups derived from the monovalent compound to the halide groups derived from the divalent compound (former:latter) is in the range of 1.00:0.80 to 1.00:10.00, and more preferably in the range of 1.00:0.90 to 1.00:5.00. As the quantitative ratio of halide groups derived from the divalent compound to the halide groups derived from the monovalent compound increases, the degree of condensation of the polyester resin tends to increase.

When using a mixture of monovalent and divalent aromatic hydroxy compounds, the ratio of the monovalent compound to the divalent compound may be determined appropriately depending on the structure of the desired polyester resin. For example, the molar ratio of aromatic hydroxy groups derived from the monovalent compound to the aromatic hydroxy groups derived from the divalent compound (former:latter) is preferably in the range of 1.00:0.80 to 1.00:10.00, and more preferably in the range of 1.00:0.90 to 1.00:5.00. As the ratio of aromatic hydroxy groups derived from the divalent compound to the aromatic hydroxy groups derived from the monovalent compound increases, the degree of condensation of the polyester resin tends to increase.

In the production method of the present invention, the amount of solvent A used as a reaction solvent is preferably 30% by mass or more, more preferably 50% by mass or more, even more preferably 60% by mass or more, 80% by mass or more, or 100% by mass or more, relative to 100% by mass of the total amount of the acid halide compound and the aromatic hydroxy compound; the upper limit is preferably 500% by mass or less, more preferably 450% by mass or less, and even more preferably 400% by mass or less. Therefore, in a preferred embodiment, the amount of solvent A added is 30 to 500% by mass, relative to 100% by mass of the total amount of the acid halide compound and the aromatic hydroxy compound.

A dehydrohalogenating agent may be used in the condensation reaction. Any conventionally known dehydrohalogenating agent, such as alkalis or amines, may be used. Examples include alkali metal hydroxides such as sodium hydroxide (caustic soda) and potassium hydroxide; and tertiary amines such as triethylamine, pyridine, and N,N-dimethyl-4-aminopyridine (DMAP). A single dehydrohalogenating agent may be used, or two or more may be used in combination. Furthermore, the amount of dehydrohalogenating agent added is not particularly limited as long as it allows the condensation reaction to proceed, and may be determined appropriately depending on the type of agent.

A phase transfer catalyst may also be used in the condensation reaction. Any known catalyst that can be used in an esterification reaction may be used.

The reaction temperature for the condensation reaction is not particularly limited as long as the condensation reaction proceeds, and may be, for example, in the range of 0 to 80°C. The reaction time for the condensation reaction is also not particularly limited as long as the desired polyester resin structure is achieved, and may be, for example, in the range of 30 minutes to 8 hours.

The polyester resin may be purified after the condensation reaction. For example, after the condensation reaction, purification steps such as water washing and microfiltration may be performed to remove by-product salts and excess starting materials from the system. Specifically, after the condensation reaction, an amount of water necessary to dissolve the by-product salts is added, and the aqueous layer containing the by-product salts is discharged from the system through oil-water separation. This process of further water washing and oil-water separation, followed by discharge of the aqueous layer containing the by-product salts, may be repeated. During this water washing and oil-water separation process, an acid may be added for neutralization, if necessary. Any conventional acid, such as disodium phosphate, may be used for neutralization. The polyester resin may then be purified by microfiltration to remove impurities through a dehydration process using chemicals or azeotropic distillation, and then, if necessary, the reaction solvent may be distilled off to obtain the polyester resin.

In a preferred embodiment, the production method of the present invention includes the following steps (1) to (4):
(1) a step of dissolving an acid halide compound and an aromatic hydroxy compound in one or more solvents A selected from the group consisting of cycloalkyl alkyl ethers and alkyltetrahydropyrans to obtain a solution;
(2) adding a dehydrohalogenating agent to the solution to carry out a condensation reaction;
(3) After the condensation reaction, water is added to separate the oil and water, thereby discharging the by-product salt from the system; and (4) further purifying the product by washing with water and separating the oil and water.

The solvent A, acid halide compound, and aromatic hydroxy compound used in step (1) are as described above, and the quantitative ratios thereof are also as described above. The method for dissolving the acid halide compound and aromatic hydroxy compound in solvent A is not particularly limited as long as they are soluble, and they can be dissolved by, for example, appropriately heating while stirring. When heating, the liquid temperature may be, for example, in the range of 20 to 40°C. In the production method of the present invention using solvent A, the acid halide compound and aromatic hydroxy compound can be easily dissolved to obtain a solution.

The dehydrohalogenating agent used in step (2) is as described above, and the reaction temperature and time for the condensation reaction are also as described above.

In step (3), water is added to the reaction solution after the condensation reaction to separate the oil and water. The aqueous layer is then discarded, allowing the by-product salt to be discharged from the system. As mentioned above, the production method of the present invention using solvent A can significantly reduce problems that occur during oil-water separation, such as the disappearance of the liquid-liquid interface and the formation of a large amount of an emulsion interlayer. This allows the by-product salt to be efficiently discharged from the system, and the desired polyester resin can be obtained with high yield. Furthermore, solvent A is safer than toluene, MIBK, and other reaction solvents that have been commonly used up to now. This, combined with the fact that this method significantly reduces problems in the production process while also taking safety into consideration.

The water washing and oil-water separation in step (4) may be carried out in the same manner as step (3). Furthermore, as explained above, acid may be added for neutralization during the water washing and oil-water separation, if necessary.

In a preferred embodiment, the production method of the present invention includes the following steps (5) and (6) in addition to the above steps (1) to (4):
(5) a step of dehydrating the mixture to precipitate by-product salts; and (6) a step of removing the by-product salts by filtration.

As mentioned above, the dehydration treatment in step (5) may be carried out using a chemical (dehydrating agent) or by azeotropic distillation. If a dehydrating agent is used, any conventionally known dehydrating agent, such as magnesium sulfate, may be used.

The filtration in step (6) may be performed using any method capable of filtering out the precipitated by-product salt produced in step (5), preferably using microfiltration using a microfiltration membrane. The material and pore size of the microfiltration membrane are not particularly limited as long as they can sufficiently filter out the precipitated by-product salt, and any conventionally known material and pore size may be selected and determined.

As mentioned above, after removing the by-product salt, the reaction solvent can be distilled off to obtain a polyester resin. In the production method of the present invention, which uses the above-mentioned solvent A as the reaction solvent, the reaction solvent may be used as the solvent for the resin composition without being removed, or only a portion of it may be removed. Because solvent A volatilizes under normal film-forming conditions, it is also useful as solvent A for constituting a varnish-like resin composition. As mentioned above, because it is highly safe, it is possible to realize a varnish-like resin composition that is highly safe.

[Resin crosslinking agent]
The polyester resin obtained by the production method of the present invention can be suitably used as a resin crosslinking agent. The present invention also provides such a resin crosslinking agent.

In one embodiment, the resin crosslinker of the present invention contains (A) a polyester resin and (B) one or more solvents selected from the group consisting of cycloalkyl alkyl ethers and alkyl tetrahydropyrans.

The polyester resin (component A), including the raw materials, acid halide compound and aromatic hydroxy compound, is as described above in the "Method for producing polyester resin" section. From the perspective of using it as a resin crosslinking agent in a resin composition, the number average molecular weight (Mn) of component (A) is preferably 5,000 or less, more preferably 4,000 or less, and even more preferably 3,500 or less or 3,000 or less. The lower limit of Mn is not particularly limited and can be, for example, 200 or more, 300 or more, 400 or more, etc. The Mn of component (A) can be measured as a polystyrene-equivalent value using gel permeation chromatography (GPC).

The solvent serving as component (B) is not particularly limited, as long as it is one or more solvents selected from the group consisting of cycloalkyl alkyl ethers and alkyltetrahydropyrans. If the reaction solvent is not removed or only a portion of it is removed during the production of the polyester resin, component (B) may be solvent A used as the reaction solvent. Therefore, in one embodiment, the resin crosslinking agent of the present invention contains a polyester resin obtained by the production method of the present invention and solvent A used as the reaction solvent. Alternatively, if the reaction solvent is removed during the production of the polyester resin, one or more solvents selected from the group consisting of cycloalkyl alkyl ethers and alkyltetrahydropyrans may be added to the resulting polyester resin. Component (B), including preferred examples thereof, is as described above in the section "Method for producing polyester resin."

In the resin crosslinking agent of the present invention, the quantitative ratio of component (A) to component (B) may be determined arbitrarily, as long as component (A) can be dissolved in component (B). Even when component (A) is a rigid-skeleton active ester resin having an aromatic polycyclic skeleton, the resin crosslinking agent of the present invention can be made to be sufficiently dissolved, which has the advantage of facilitating the preparation of the resin composition described below.

[Resin composition]
A resin composition can be produced using the polyester resin obtained by the production method of the present invention. The present invention also provides such a resin composition. For example, the resin composition of the present invention may contain a crosslinkable resin and a polyester resin, and the polyester resin is a polyester resin obtained by the production method of the present invention.

In one embodiment, the resin composition of the present invention contains (A) a polyester resin, (B) one or more solvents selected from the group consisting of cycloalkyl alkyl ethers and alkyltetrahydropyrans, and (C) a crosslinkable resin.

The polyester resin (component (A)) is as described above in the "Method for Producing Polyester Resin" section, including the raw materials, acid halide compound and aromatic hydroxy compound. The preferred range for its number average molecular weight (Mn) is as described above in the "Resin Crosslinking Agent" section.

The solvent (B) is not particularly limited as long as it is one or more solvents selected from the group consisting of cycloalkyl alkyl ethers and alkyltetrahydropyrans. If the reaction solvent is not removed or only a portion of it is removed during the production of the polyester resin, component (B) may be solvent A used as the reaction solvent. Therefore, in one embodiment, the resin composition of the present invention contains a polyester resin obtained by the production method of the present invention, solvent A used as the reaction solvent, and a crosslinkable resin. Alternatively, if the reaction solvent is completely removed during the production of the polyester resin, one or more solvents selected from the group consisting of cycloalkyl alkyl ethers and alkyltetrahydropyrans may be added to the resulting polyester resin together with the crosslinkable resin. Component (B), including preferred examples thereof, is as described above in the "Method for producing polyester resins" section.

The type of crosslinkable resin used as component (C) is not particularly limited, as long as it is capable of crosslinking when combined with component (A). From the perspective of being able to produce a cured product with excellent dielectric properties when combined with component (A), component (C) is preferably one or more resins selected from the group consisting of thermosetting resins and radically polymerizable resins.

Thermosetting resins and radically polymerizable resins may be known resins used to form insulating layers for printed wiring boards and semiconductor chip packages. Below, we will explain the thermosetting resins and radically polymerizable resins that can be used as component (C).

Examples of thermosetting resins include epoxy resins, benzocyclobutene resins, epoxy acrylate resins, urethane acrylate resins, urethane resins, cyanate resins, polyimide resins, benzoxazine resins, unsaturated polyester resins, phenolic resins, melamine resins, silicone resins, and phenoxy resins. Thermosetting resins may be used alone or in combination with two or more. Of these, it is preferable for component (C) to contain an epoxy resin, as this, when combined with component (A), can result in a cured product with excellent dielectric properties.

The type of epoxy resin is not particularly limited, as long as it has one or more (preferably two or more) epoxy groups per molecule. Examples of epoxy resins include bisphenol A epoxy resins, bisphenol F epoxy resins, bisphenol S epoxy resins, bisphenol AF epoxy resins, phenol novolac epoxy resins, tert-butyl-catechol epoxy resins, naphthol epoxy resins, naphthalene epoxy resins, naphthylene ether epoxy resins, glycidylamine epoxy resins, glycidyl ester epoxy resins, cresol novolac epoxy resins, biphenyl epoxy resins, phenol aralkyl epoxy resins, biphenyl aralkyl epoxy resins, fluorene skeleton epoxy resins, dicyclopentadiene epoxy resins, anthracene epoxy resins, linear aliphatic epoxy resins, epoxy resins with a butadiene structure, alicyclic epoxy resins, heterocyclic epoxy resins, spiro ring-containing epoxy resins, cyclohexanedimethanol epoxy resins, trimethylol epoxy resins, and halogenated epoxy resins.

Epoxy resins can be classified into those that are liquid at a temperature of 20°C (hereinafter referred to as "liquid epoxy resins") and those that are solid at a temperature of 20°C (hereinafter referred to as "solid epoxy resins"). The resin composition of the present invention may contain, as component (C), only a liquid epoxy resin, only a solid epoxy resin, or a combination of a liquid epoxy resin and a solid epoxy resin. When a combination of a liquid epoxy resin and a solid epoxy resin is contained, the blending ratio (liquid:solid) may be in the range of 20:1 to 1:20 by mass (preferably 10:1 to 1:10, more preferably 3:1 to 1:3).

The epoxy group equivalent of the epoxy resin is preferably 50 g/eq. to 2000 g/eq., more preferably 60 g/eq. to 1000 g/eq., and even more preferably 80 g/eq. to 500 g/eq. The epoxy group equivalent is the mass of the epoxy resin containing one equivalent of epoxy groups, and can be measured in accordance with JIS K7236.

The weight-average molecular weight (Mw) of the epoxy resin is preferably 100 to 5,000, more preferably 250 to 3,000, and even more preferably 400 to 1,500. The Mw of the epoxy resin can be measured as a polystyrene-equivalent value using the GPC method.

The type of radically polymerizable resin is not particularly limited, as long as it has one or more (preferably two or more) radically polymerizable unsaturated groups per molecule. Examples of radically polymerizable resins include resins having one or more radically polymerizable unsaturated groups selected from maleimide groups, vinyl groups, allyl groups, styryl groups, vinylphenyl groups, acryloyl groups, methacryloyl groups, fumaroyl groups, and maleoyl groups. In particular, from the viewpoint of being able to produce a cured product with excellent dielectric properties when combined with component (A), it is preferable that component (C) contain one or more resins selected from maleimide resins, (meth)acrylic resins, and styryl resins.

There is no particular limitation on the type of maleimide resin, as long as it contains one or more (preferably two or more) maleimide groups (2,5-dihydro-2,5-dioxo-1H-pyrrol-1-yl groups) per molecule. Examples of maleimide resins include maleimide resins containing an aliphatic skeleton with 36 carbon atoms derived from dimer diamine, such as "BMI-3000J," "BMI-5000," "BMI-1400," "BMI-1500," "BMI-1700," and "BMI-689" (all manufactured by DigiCner Molecules); maleimide resins containing an indane skeleton, as described in the Japan Institute of Invention and Innovation Disclosure Technical Bulletin No. 2020-500211; and maleimide resins containing an aromatic ring skeleton directly bonded to the nitrogen atom of the maleimide group, such as "MIR-3000-70MT" (manufactured by Nippon Kayaku Co., Ltd.), "BMI-4000" (manufactured by Daiwa Kasei Co., Ltd.), and "BMI-80" (manufactured by Keiai Kasei Co., Ltd.).

There are no particular restrictions on the type of (meth)acrylic resin, as long as it contains one or more (preferably two or more) (meth)acryloyl groups per molecule. Here, the term "(meth)acryloyl group" is a general term for acryloyl groups and methacryloyl groups. Examples of methacrylic resins include "A-DOG" (manufactured by Shin-Nakamura Chemical Co., Ltd.), "DCP-A" (manufactured by Kyoeisha Chemical Co., Ltd.), "NPDGA," "FM-400," "R-687," "THE-330," "PET-30," and "DPHA" (all manufactured by Nippon Kayaku Co., Ltd.).

The type of styryl resin is not particularly limited, as long as it contains one or more (preferably two or more) styryl groups or vinylphenyl groups per molecule. Examples of styryl resins include "OPE-2St," "OPE-2St 1200," and "OPE-2St 2200" (all manufactured by Mitsubishi Gas Chemical Company, Inc.).

The resin composition of the present invention may contain, as component (C), only a thermosetting resin, only a radically polymerizable resin, or a combination of a thermosetting resin and a radically polymerizable resin.

In the resin composition of the present invention, the mass ratio of component (A) to component (C) ((A)/(C)) is not particularly limited as long as component (C) is capable of crosslinking, but is preferably 0.2 or greater, more preferably 0.4 or greater, 0.5 or greater, 0.6 or greater, 0.8 or greater, or 1 or greater. The upper limit of this mass ratio ((A)/(C)) may be, for example, 2 or less, 1.9 or less, or 1.8 or less. Therefore, in one embodiment, the mass ratio of component (A) to component (C) ((A)/(C)) is 0.2 to 2.0.

The resin composition of the present invention may further contain an inorganic filler. By including an inorganic filler, the linear thermal expansion coefficient and dielectric loss tangent can be further reduced.

Inorganic fillers include, for example, silica, alumina, barium sulfate, talc, clay, mica powder, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum borate, barium titanate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, barium zirconate, and calcium zirconate, and may be selected according to the specific application. Inorganic fillers may be used alone or in combination of two or more. Commercially available inorganic fillers include, for example, "UFP-30" (manufactured by Denka Chemical Industry Co., Ltd.); "YC100C," "YA050C," "YA050C-MJE," "YA010C," "SC2500SQ," "SC4050-SX," "SO-C4," "SO-C2," "SO-C1," and "SC-C2" (all manufactured by Admatechs Co., Ltd.); "Silfil NSS-3N," "Silfil NSS-4N," and "Silfil NSS-5N" (manufactured by Tokuyama Corporation), and "DAW-0525" (manufactured by Denka Company Limited).

The average particle size of the inorganic filler may be determined within a suitable range depending on the specific application. For example, when forming an interlayer insulating layer for a printed wiring board or a rewiring formation layer for a semiconductor chip package, the average particle size of the inorganic filler is preferably 5 μm or less, more preferably 2 μm or less, and even more preferably 1 μm or less, to ensure a low surface roughness of the cured product (insulating layer) and facilitate the formation of fine wiring. Furthermore, when forming an encapsulating layer for a semiconductor chip package, the average particle size of the inorganic filler is preferably 15 μm or less, more preferably 14 μm or less, even more preferably 12 μm or less, 10 μm or less, or 8 μm or less, to improve fluidity during encapsulation molding. The lower limit of the average particle size is not particularly limited and may be determined depending on the specific application, and may be, for example, 0.01 μm or more, 0.02 μm or more, 0.03 μm or more, 0.05 μm or more, or 0.1 μm or more. The average particle size of the inorganic filler can be measured using a laser diffraction/scattering method based on Mie scattering theory. Specifically, a particle size distribution of the inorganic filler is created on a volume basis using a laser diffraction scattering particle size distribution analyzer, and the median diameter is used as the average particle size. A preferred measurement sample is one in which the inorganic filler is dispersed in water using ultrasonic waves. An example of a laser diffraction scattering particle size distribution analyzer that can be used is the LA-950 manufactured by Horiba, Ltd.

It is preferable that the inorganic filler be surface-treated with a surface treatment agent such as an aminosilane coupling agent, a ureidosilane coupling agent, an epoxysilane coupling agent, a mercaptosilane coupling agent, a vinylsilane coupling agent, a styrylsilane coupling agent, an acrylatesilane coupling agent, an isocyanatesilane coupling agent, a sulfidesilane coupling agent, an organosilazane compound, or a titanate coupling agent to improve its moisture resistance and dispersibility.

When the resin composition of the present invention contains an inorganic filler, the content of the inorganic filler in the resin composition may be determined depending on the properties required of the resin composition. Taking the non-volatile components in the resin composition as 100% by mass, the content is, for example, 5% by mass or more, 10% by mass or more, preferably 30% by mass or more, more preferably 40% by mass or more, and even more preferably 50% by mass or more, 60% by mass or more, 65% by mass or more, 70% by mass or more, 75% by mass or more, or 80% by mass or more. The upper limit of the content of the inorganic filler in the resin composition is not particularly limited, but can be, for example, 95% by mass or less, 90% by mass or less, etc.

The resin composition of the present invention may further contain a resin crosslinking agent other than a polyester resin.

Resin crosslinking agents other than polyester resins include "TD2090" and "TD2131" (manufactured by DIC Corporation), "MEH-7600", "MEH-7851", and "MEH-8000H" (manufactured by Meiwa Kasei Co., Ltd.), "NHN", "CBN", "GPH-65", and "GPH-103" (manufactured by Nippon Kayaku Co., Ltd.), "SN170", "SN180", "SN190", "SN475", "SN485", "SN495", "SN375", and "SN395" (manufactured by Nippon Steel Chemical & Material Co., Ltd.), and "LA70" Examples include phenol-based curing agents such as "52," "LA7054," "LA3018," and "LA1356" (manufactured by DIC Corporation); benzoxazine-based crosslinking agents such as "F-a" and "P-d" (manufactured by Shikoku Kasei Corporation) and "HFB2006M" (manufactured by Showa Polymer Co., Ltd.); acid anhydride-based crosslinking agents such as methylhexahydrophthalic anhydride, methyl nadic anhydride, and hydrogenated methyl nadic anhydride; and cyanate ester-based crosslinking agents such as PT30, PT60, and BA230S75 (manufactured by Lonza Japan).

When the resin composition of the present invention contains a resin crosslinking agent other than a polyester resin, the content of the resin crosslinking agent in the resin composition may be determined depending on the properties required of the resin composition. Given that the non-volatile components in the resin composition are 100% by mass, the content is preferably 40% by mass or less, more preferably 20% by mass or less, and even more preferably 10% by mass or less. The lower limit may be 0.01% by mass or more, 0.05% by mass or more, 0.1% by mass or more, etc.

The resin composition of the present invention may further contain a crosslinking accelerator. By including a crosslinking accelerator, the crosslinking time and crosslinking temperature can be efficiently adjusted.

Examples of crosslinking accelerators include organic phosphine compounds such as "TPP," "TPP-K," "TPP-S," and "TPTP-S" (manufactured by Hokko Chemical Industry Co., Ltd.); imidazole compounds such as "Curesol 2MZ," "2E4MZ," "Cl1Z," "Cl1Z-CN," "Cl1Z-CNS," "Cl1Z-A," "2MZ-OK," "2MA-OK," and "2PHZ" (manufactured by Shikoku Chemical Industry Co., Ltd.); amine adduct compounds such as Novacure (manufactured by Asahi Chemical Industry Co., Ltd.) and Fujicure (manufactured by Fuji Chemical Industry Co., Ltd.); amine compounds such as 1,8-diazabicyclo[5,4,0]undecene-7,4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, and 4-dimethylaminopyridine; and organometallic complexes or organometallic salts of cobalt, copper, zinc, iron, nickel, manganese, tin, etc.

When the resin composition of the present invention contains a crosslinking accelerator, the content of the crosslinking accelerator in the resin composition may be determined depending on the properties required of the resin composition. Given that the non-volatile components in the resin composition are 100% by mass, the content is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 1% by mass or less. The lower limit may be 0.001% by mass or more, 0.01% by mass or more, 0.05% by mass or more, etc.

The resin composition of the present invention may further contain optional additives. Examples of such additives include organic fillers such as rubber particles; radical polymerization initiators such as peroxide-based radical polymerization initiators and azo-based radical polymerization initiators; thermoplastic resins such as phenoxy resin, polyvinyl acetal resin, polysulfone resin, polyethersulfone resin, polyphenylene ether resin, polyetheretherketone resin, and polyester resin; organometallic compounds such as organocopper compounds, organozinc compounds, and organocobalt compounds; colorants such as phthalocyanine blue, phthalocyanine green, iodine green, diazo yellow, crystal violet, titanium oxide, and carbon black; polymerization inhibitors such as hydroquinone, catechol, pyrogallol, and phenothiazine; leveling agents such as silicone-based leveling agents and acrylic polymer-based leveling agents; thickeners such as bentone and montmorillonite; defoamers such as silicone-based defoamers, acrylic defoamers, fluorine-based defoamers, and vinyl resin-based defoamers; and benzotriazole. surfactants such as fluorine-based surfactants and silicone-based surfactants; flame retardants such as phosphorus-based flame retardants (e.g., phosphate ester compounds, phosphazene compounds, phosphinic acid compounds, red phosphorus), nitrogen-based flame retardants (e.g., melamine sulfate), halogen-based flame retardants, and inorganic flame retardants (e.g., antimony trioxide); dispersants such as phosphate ester-based dispersants, polyoxyalkylene-based dispersants, acetylene-based dispersants, silicone-based dispersants, anionic dispersants, and cationic dispersants; and stabilizers such as borate-based stabilizers, titanate-based stabilizers, aluminate-based stabilizers, zirconate-based stabilizers, isocyanate-based stabilizers, carboxylic acid-based stabilizers, and carboxylic acid anhydride-based stabilizers. The content of such additives may be determined depending on the properties required of the resin composition.

The resin composition of the present invention may further contain an organic solvent other than component (B) (hereinafter also referred to as "other organic solvent") as a volatile component. Examples of other organic solvents include ketone solvents such as acetone, methyl ethyl ketone, and cyclohexanone; ester solvents such as methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, isoamyl acetate, methyl propionate, ethyl propionate, and γ-butyrolactone; ether solvents such as tetrahydropyran, tetrahydrofuran, 1,4-dioxane, diethyl ether, diisopropyl ether, dibutyl ether, and diphenyl ether; alcohol solvents such as methanol, ethanol, propanol, butanol, and ethylene glycol; 2-ethoxyethyl acetate, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl diglycol acetate, γ-butyrolactone, and methoxypropionic acid. ether alcohol solvents such as methyl lactate, ethyl lactate, and methyl 2-hydroxyisobutyrate; ether alcohol solvents such as 2-methoxypropanol, 2-methoxyethanol, 2-ethoxyethanol, propylene glycol monomethyl ether, and diethylene glycol monobutyl ether (butyl carbitol); amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone; sulfoxide solvents such as dimethyl sulfoxide; nitrile solvents such as acetonitrile and propionitrile; aliphatic hydrocarbon solvents such as hexane, cyclopentane, cyclohexane, and methylcyclohexane; and aromatic hydrocarbon solvents such as ethylbenzene and trimethylbenzene. These other organic solvents may be used alone or in combination of two or more.

The resin composition of the present invention can be prepared by appropriately mixing the necessary components from among the above ingredients, and, if necessary, kneading or mixing them using kneading means such as a triple roll mill, ball mill, bead mill, or sand mill, or stirring means such as a super mixer or planetary mixer. When the resin composition of the present invention contains a combination of component (A) and component (B), the resin composition can be easily prepared because component (A) is easily dissolved.

The resin composition of the present invention can be suitably used as a resin composition for encapsulating semiconductor chips (semiconductor encapsulation resin composition). The resin composition of the present invention can also be suitably used as a resin composition for forming a rewiring layer (resin composition for rewiring layer) as an insulating layer for forming a rewiring layer in a semiconductor chip package. The resin composition of the present invention can also be suitably used as a resin composition for forming an insulating layer of a printed wiring board (resin composition for insulating layer of printed wiring board), and more suitably as a resin composition for forming an interlayer insulating layer of a printed wiring board (resin composition for insulating interlayer of printed wiring board). The resin composition of the present invention can also be suitably used when the printed wiring board is a circuit board with built-in components. The resin composition of the present invention can also be used in a wide range of applications requiring a resin composition, such as sheet-like laminate materials such as resin sheets and prepregs, solder resists, underfill materials, die bonding materials, hole-filling resins, and component-embedding resins.

[Sheet-like laminated materials (resin sheets, prepregs)]
The resin composition of the present invention can be used as it is, but may also be used in the form of a sheet-like laminate material containing the resin composition.

The following resin sheets and prepregs are preferred as sheet-like laminate materials.

In one embodiment, the resin sheet includes a support and a layer of a resin composition (hereinafter simply referred to as a "resin composition layer") provided on the support, and is characterized in that the resin composition layer is formed from the resin composition of the present invention.

The optimum thickness of the resin composition layer varies depending on the application, and may be determined appropriately depending on the application. For example, from the perspective of reducing the thickness of printed wiring boards and semiconductor chip packages, the thickness of the resin composition layer is preferably 200 μm or less, and more preferably 150 μm or less, 120 μm or less, 100 μm or less, 80 μm or less, 60 μm or less, or 50 μm or less. There is no particular lower limit to the thickness of the resin composition layer, but it can typically be 1 μm or more, 5 μm or more, etc.

Examples of the support include films made of plastic materials, metal foils, and release paper, with films made of plastic materials and metal foils being preferred.

When a film made of a plastic material is used as the support, examples of the plastic material include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), acrylics such as polycarbonate (PC) and polymethyl methacrylate (PMMA), cyclic polyolefins, triacetyl cellulose (TAC), polyether sulfide (PES), polyether ketone, and polyimides. Among these, polyethylene terephthalate and polyethylene naphthalate are preferred, with inexpensive polyethylene terephthalate being particularly preferred.

When a metal foil is used as the support, examples of the metal foil include copper foil and aluminum foil, with copper foil being preferred. The copper foil may be a foil made of the single metal copper, or a foil made of an alloy of copper and another metal (e.g., tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, etc.).

The surface of the support that will be bonded to the resin composition layer may be matte-treated, corona-treated, or antistatic-treated. Alternatively, a support with a release layer, which has a release layer on the surface that will be bonded to the resin composition layer, may be used. Examples of release agents used in the release layer of the support with a release layer include one or more release agents selected from the group consisting of alkyd resins, polyolefin resins, urethane resins, and silicone resins. Commercially available support with a release layer may be used, including PET films with a release layer primarily composed of alkyd resin-based release agents, such as "SK-1," "AL-5," and "AL-7" manufactured by Lintec Corporation, "Lumirror T60" manufactured by Toray Industries, Inc., "Purex" manufactured by Teijin Limited, and "Uni-Peel" manufactured by Unitika Limited.

The thickness of the support is not particularly limited, but is preferably in the range of 5 μm to 75 μm, and more preferably in the range of 10 μm to 60 μm. When using a support with a release layer, it is preferable that the overall thickness of the support with a release layer be in the above range.

The support may also be a metal foil with a support substrate, which is a thin metal foil with a peelable support substrate laminated thereto. In one embodiment, the metal foil with a support substrate includes a support substrate, a release layer provided on the support substrate, and metal foil provided on the release layer. When a metal foil with a support substrate is used as the support, the resin composition layer is provided on the metal foil.

In metal foil with a supporting substrate, the material of the supporting substrate is not particularly limited, but examples include copper foil, aluminum foil, stainless steel foil, titanium foil, copper alloy foil, etc. When copper foil is used as the supporting substrate, it may be electrolytic copper foil or rolled copper foil. In addition, the release layer is not particularly limited as long as it allows the metal foil to be released from the supporting substrate, and examples include an alloy layer of an element selected from the group consisting of Cr, Ni, Co, Fe, Mo, Ti, W, and P; an organic coating, etc.

For metal foil with a supporting substrate, the material of the metal foil is preferably, for example, copper foil or copper alloy foil.

In metal foil with a supporting substrate, the thickness of the supporting substrate is not particularly limited, but is preferably in the range of 10 μm to 150 μm, and more preferably in the range of 10 μm to 100 μm. The thickness of the metal foil may be, for example, in the range of 0.1 μm to 10 μm.

In one embodiment, the resin sheet may further include an optional layer, as needed. Examples of such optional layers include a protective film provided on the surface of the resin composition layer that is not bonded to the support (i.e., the surface opposite the support). The thickness of the protective film is not particularly limited, but is, for example, 1 μm to 40 μm. By laminating a protective film, it is possible to prevent the adhesion of dust and other particles to the surface of the resin composition layer and to prevent scratches.

A resin sheet can be produced, for example, by preparing a varnish-like resin composition, applying it to a support using a die coater or the like, and then drying it to form a resin composition layer.

Drying may be carried out by known methods such as heating or hot air blowing. While the drying conditions are not particularly limited, drying is carried out so that the organic solvent content in the resin composition layer is 10% by mass or less, preferably 5% by mass or less. For example, when using a resin composition containing 30% to 60% by mass of organic solvent, although this varies depending on the boiling point of the organic solvent in the resin composition, a resin composition layer can be formed by drying at 50°C to 150°C for 3 to 10 minutes. When component (B) is included as the organic solvent, component (B) volatilizes under normal film-forming conditions and, as mentioned above, is highly safe, allowing for the production of resin sheets with careful consideration given to safety.

The resin sheet can be stored rolled up. If the resin sheet has a protective film, it can be used by peeling off the protective film.

In one embodiment, the prepreg is formed by impregnating a sheet-like fiber substrate with the resin composition of the present invention.

The sheet-like fiber substrate used for the prepreg is not particularly limited, and commonly used prepreg substrates such as glass cloth, aramid nonwoven fabric, and liquid crystal polymer nonwoven fabric can be used. From the perspective of thinning printed wiring boards and semiconductor chip packages, the thickness of the sheet-like fiber substrate is preferably 50 μm or less, more preferably 40 μm or less, even more preferably 30 μm or less, and particularly preferably 20 μm or less. There is no particular lower limit to the thickness of the sheet-like fiber substrate. It is usually 10 μm or more.

Prepregs can be manufactured using known methods such as the hot melt method and the solvent method.

The thickness of the prepreg can be in the same range as the resin composition layer in the resin sheet described above.

The sheet-like laminate material of the present invention can be suitably used for encapsulating semiconductor chips (for semiconductor encapsulation) and can be suitably used as a rewiring formation layer, serving as an insulating layer for forming a rewiring layer. The sheet-like laminate material of the present invention can also be suitably used for forming an insulating layer of a printed wiring board (for an insulating layer of a printed wiring board), and can be even more suitably used for forming an interlayer insulating layer of a printed wiring board (for an insulating interlayer of a printed wiring board).

[Semiconductor chip package]
The semiconductor chip package of the present invention includes a sealing layer made of a cured product of the resin composition of the present invention. As described above, the semiconductor chip package of the present invention may also include an insulating layer (rewiring formation layer) for forming a rewiring layer made of a cured product of the resin composition of the present invention.

A semiconductor chip package can be manufactured, for example, by a method including the following steps (1) to (6) using the resin composition and resin sheet of the present invention. The resin composition and resin sheet of the present invention can be used to form the sealing layer in step (3) or the rewiring formation layer in step (5). An example of forming a sealing layer or a rewiring formation layer using a resin composition or a resin sheet will be shown below. However, techniques for forming sealing layers and rewiring formation layers for semiconductor chip packages are known, and a person skilled in the art can manufacture a semiconductor package using the resin composition and resin sheet of the present invention according to known techniques.
(1) A step of laminating a temporary fixing film on a substrate;
(2) A step of temporarily fixing a semiconductor chip on a temporary fixing film;
(3) forming an encapsulation layer on the semiconductor chip;
(4) peeling the substrate and the temporary fixing film from the semiconductor chip;
(5) forming a rewiring formation layer as an insulating layer on the surface of the semiconductor chip from which the base material and the temporary fixing film have been peeled off; and (6) forming a rewiring layer as a conductor layer on the rewiring formation layer.

-Process (1)-
The material used for the substrate is not particularly limited, and examples of the substrate include a silicon wafer, a glass wafer, a glass substrate, a metal substrate such as copper, titanium, stainless steel, or cold-rolled steel plate (SPCC), a substrate in which glass fiber is impregnated with epoxy resin or the like and subjected to a thermosetting treatment (e.g., an FR-4 substrate), and a substrate made of bismaleimide triazine resin (BT resin).

The material of the temporary fixing film is not particularly limited as long as it can be peeled off from the semiconductor chip in step (4) and can temporarily fix the semiconductor chip. Commercially available temporary fixing films can be used. Examples of commercially available products include Riva Alpha manufactured by Nitto Denko Corporation.

-Process (2)-
The semiconductor chip is temporarily fixed on the temporary fixing film so that its electrode pad surface is bonded to the temporary fixing film. The temporary fixing of the semiconductor chip can be performed using a known device such as a flip chip bonder or a die bonder. The layout and number of semiconductor chips to be arranged can be appropriately set depending on the shape and size of the temporary fixing film, the number of semiconductor packages to be produced, etc., and for example, the semiconductor chips can be temporarily fixed by arranging them in a matrix of multiple rows and multiple columns.

-Process (3)-
The resin composition of the present invention is applied onto a semiconductor chip, or a resin composition layer of the resin sheet of the present invention is laminated onto a semiconductor chip and cured (for example, thermally cured) to form an encapsulating layer.

For example, when used in the form of a resin sheet, the semiconductor chip and resin sheet can be laminated by removing the protective film from the resin sheet and then thermocompressing the resin sheet to the semiconductor chip from the support side. Examples of the member that thermocompresses the resin sheet to the semiconductor chip (hereinafter also referred to as the "thermocompression member") include a heated metal plate (such as a stainless steel plate) or a metal roll (such as a stainless steel roll). It is preferable to press the thermocompression member not directly onto the resin sheet, but rather via an elastic material such as heat-resistant rubber, so that the resin sheet can adequately conform to the surface irregularities of the semiconductor chip. The semiconductor chip and resin sheet can also be laminated using a vacuum lamination method. The lamination conditions and preferred ranges are the same as those described below in connection with the method for manufacturing a printed wiring board.

After lamination, the resin composition is thermally cured to form the sealing layer. The thermal curing conditions are the same as those described below in connection with the method for manufacturing a printed wiring board.

The support for the resin sheet may be peeled off after the resin sheet is laminated on the semiconductor chip and thermally cured, or the support may be peeled off before the resin sheet is laminated on the semiconductor chip.

When forming a sealing layer by applying the resin composition of the present invention, the application conditions may be the same as the application conditions for forming the resin composition layer described in relation to the resin sheet of the present invention.

-Process (4)-
The method for peeling off the substrate and the temporary fixing film can be changed as appropriate depending on the material of the temporary fixing film, etc., and examples include a method in which the temporary fixing film is heated and foamed (or expanded) to peel it off, and a method in which ultraviolet light is irradiated from the substrate side to reduce the adhesive strength of the temporary fixing film and peel it off.

In the method of peeling off the temporary fixing film by heating and foaming (or expanding) it, the heating conditions are usually 100 to 250° C. for 1 to 90 seconds or 5 to 15 minutes. In the method of peeling off the temporary fixing film by irradiating it with ultraviolet light from the substrate side to reduce the adhesive strength of the temporary fixing film, the irradiation dose of ultraviolet light is usually 10 mJ/cm ² to 1000 mJ/cm ² .

-Process (5)-
The material for forming the rewiring formation layer (insulating layer) is not particularly limited as long as it has insulating properties when the rewiring formation layer (insulating layer) is formed, and from the viewpoint of ease of manufacturing a semiconductor chip package, a photosensitive resin or a thermosetting resin is preferred. The rewiring formation layer may be formed using the resin composition or resin sheet of the present invention.

After forming the redistribution layer, via holes may be formed in the redistribution layer to establish interlayer connections between the semiconductor chip and the conductor layer described below. The via holes may be formed using known methods depending on the material of the redistribution layer.

-Process (6)-
The material of the conductor layer formed on the redistribution layer is not particularly limited. In a preferred embodiment, the conductor layer contains one or more metals selected from the group consisting of gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, and indium. The conductor layer may be a single metal layer or an alloy layer. Examples of the alloy layer include a layer formed from an alloy of two or more metals selected from the above group (e.g., a nickel-chromium alloy, a copper-nickel alloy, and a copper-titanium alloy). Among these, from the viewpoints of versatility, cost, ease of patterning, etc., of the conductor layer formation, a single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or an alloy layer of a nickel-chromium alloy, a copper-nickel alloy, or a copper-titanium alloy is preferred. A single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or an alloy layer of a nickel-chromium alloy is more preferred, and a single metal layer of copper is even more preferred.

The conductor layer may have a single-layer structure, or a multi-layer structure consisting of two or more single-metal or alloy layers made of different types of metals or alloys. If the conductor layer has a multi-layer structure, the layer in contact with the insulating layer is preferably a single-metal layer of chromium, zinc, or titanium, or an alloy layer of nickel-chromium alloy.

The thickness of the conductor layer depends on the desired semiconductor chip package design, but is generally between 1 μm and 35 μm, preferably between 1 μm and 20 μm.

In one embodiment, the conductor layer may be formed by plating. For example, a conductor layer having the desired wiring pattern can be formed by plating the surface of the rewiring formation layer using conventional techniques such as semi-additive and full-additive methods. From the perspective of ease of manufacturing, formation by a semi-additive method is preferred. Below is an example of forming a conductor layer by a semi-additive method.

First, a plating seed layer is formed on the surface of the rewiring formation layer by electroless plating. Next, a mask pattern is formed on the formed plating seed layer, exposing a portion of the plating seed layer corresponding to the desired wiring pattern. A metal layer is formed on the exposed plating seed layer by electrolytic plating, and the mask pattern is then removed. Unnecessary plating seed layer is then removed by etching or other methods, forming a conductor layer (rewiring layer) with the desired wiring pattern.

In addition, steps (5) and (6) may be repeated to alternately stack (build up) conductor layers (rewiring layers) and rewiring formation layers (insulating layers).

When manufacturing a semiconductor chip package, the following steps may be further performed: (7) forming a solder resist layer on the conductor layer (rewiring layer), (8) forming bumps, and (9) dicing multiple semiconductor chip packages into individual semiconductor chip packages. These steps may be performed according to various methods known to those skilled in the art that are used in the manufacture of semiconductor chip packages.

The above is an example of a manufacturing method in which a semiconductor chip is first provided and then a rewiring layer is formed on the electrode pad surface, i.e., a chip-1st (Chip- ^1st ) method. In addition to the chip-1st method, the semiconductor chip package of the present invention may also be manufactured by a method in which a rewiring layer is first provided, and then a semiconductor chip is provided on the rewiring layer in a state in which the electrode pad surface can be electrically connected to the rewiring layer, and then sealed, i.e., a rewiring layer-1st (RDL- ^1st ) method.

By forming an encapsulating layer and a rewiring formation layer using the resin composition and resin sheet of the present invention, a semiconductor chip package with low transmission loss can be realized, regardless of whether the semiconductor package is a fan-in package or a fan-out package. In one embodiment, the semiconductor chip package of the present invention is a fan-out package. The resin composition and resin sheet of the present invention can be applied to both fan-out panel level packages (FOPLPs) and fan-out wafer level packages (FOWLPs). In one embodiment, the semiconductor package of the present invention is a fan-out panel level package (FOPLP). In another embodiment, the semiconductor package of the present invention is a fan-out wafer level package (FOWLP).

[Printed wiring board]
The printed wiring board of the present invention includes an insulating layer made of a cured product of the resin composition of the present invention.

The printed wiring board can be produced, for example, by using the above-mentioned resin sheet by a method including the following steps (I) and (II).
(I) a step of laminating a resin sheet on an inner layer substrate so that the resin composition layer of the resin sheet is bonded to the inner layer substrate; and (II) a step of curing (e.g., thermally curing) the resin composition layer to form an insulating layer.

The "inner layer substrate" used in step (I) refers to a component that will become the substrate of a printed wiring board, and examples include glass epoxy substrates, metal substrates, polyester substrates, polyimide substrates, BT resin substrates, and thermosetting polyphenylene ether substrates. The substrate may also have a conductor layer on one or both sides, and this conductor layer may be patterned. An inner layer substrate with a conductor layer (circuit) formed on one or both sides of the substrate is sometimes referred to as an "inner layer circuit board." Furthermore, the term "inner layer substrate" used in this invention also includes intermediate products on which insulating layers and/or conductor layers are to be further formed during the manufacture of a printed wiring board. When the printed wiring board is a component-embedded circuit board, an inner layer substrate with embedded components may be used.

The inner layer substrate and resin sheet can be laminated, for example, by thermocompression bonding the resin sheet to the inner layer substrate from the support side. Examples of the member that thermocompresses the resin sheet to the inner layer substrate (hereinafter also referred to as the "thermocompression member") include a heated metal plate (such as a SUS panel) or a metal roll (SUS roll). The thermocompression member may be pressed directly onto the resin sheet, or it may be pressed via an elastic material such as heat-resistant rubber so that the resin sheet can adequately conform to the surface irregularities of the inner layer substrate.

The lamination of the inner layer substrate and the resin sheet may be carried out by vacuum lamination. In vacuum lamination, the thermocompression temperature is preferably in the range of 60°C to 160°C, more preferably 80°C to 140°C, the thermocompression pressure is preferably in the range of 0.098 MPa to 1.77 MPa, more preferably 0.29 MPa to 1.47 MPa, and the thermocompression time is preferably in the range of 20 seconds to 400 seconds, more preferably 30 seconds to 300 seconds. Lamination is preferably carried out under reduced pressure conditions of 26.7 hPa or less.

Lamination can be performed using a commercially available vacuum laminator. Examples of commercially available vacuum laminators include the vacuum pressure laminator manufactured by Meiki Seisakusho Co., Ltd., the vacuum applicator manufactured by Nikko Materials Co., Ltd., and the batch vacuum pressure laminator.

After lamination, the laminated resin sheets may be smoothed under normal pressure (atmospheric pressure), for example, by pressing a thermocompression member from the support side. The pressing conditions for the smoothing process may be the same as the thermocompression conditions for lamination described above. The smoothing process may be performed using a commercially available laminator. Note that lamination and smoothing may also be performed consecutively using the commercially available vacuum laminator described above.

The support may be removed between step (I) and step (II), or after step (II). When a metal foil is used as the support, the conductor layer may be formed using the metal foil without peeling off the support. When a metal foil with a supporting substrate is used as the support, the supporting substrate (and release layer) may be peeled off. Then, the conductor layer may be formed using the metal foil.

In step (II), the resin composition layer is cured (e.g., thermally cured) to form an insulating layer made of the cured resin composition. The curing conditions for the resin composition layer are not particularly limited, and conditions typically used for forming insulating layers for printed wiring boards may be used.

For example, the thermal curing conditions for the resin composition layer vary depending on the type of resin composition, but in one embodiment, the curing temperature is preferably 120°C to 250°C, more preferably 150°C to 240°C, and even more preferably 180°C to 230°C. The curing time is preferably 5 minutes to 240 minutes, more preferably 10 minutes to 150 minutes, and even more preferably 15 minutes to 120 minutes.

Before thermally curing the resin composition layer, the resin composition layer may be preheated at a temperature lower than the curing temperature. For example, prior to thermally curing the resin composition layer, the resin composition layer may be preheated at a temperature of 50°C to 120°C, preferably 60°C to 115°C, and more preferably 70°C to 110°C for 5 minutes or more, preferably 5 minutes to 150 minutes, more preferably 15 minutes to 120 minutes, and even more preferably 15 minutes to 100 minutes.

When manufacturing a printed wiring board, the following steps may be further carried out: (III) drilling holes in the insulating layer; (IV) roughening the insulating layer; and (V) forming a conductor layer. These steps (III) through (V) may be carried out according to various methods known to those skilled in the art and used in the manufacture of printed wiring boards. If the support is removed after step (II), the removal of the support may be carried out between steps (II) and (III), between steps (III) and (IV), or between steps (IV) and (V). Furthermore, if necessary, the formation of the insulating layer and conductor layer in steps (I) through (V) may be repeated to form a multilayer wiring board.

In another embodiment, the printed wiring board of the present invention can be manufactured using the prepreg described above. The manufacturing method is basically the same as when a resin sheet is used.

Step (III) is a step of drilling holes in the insulating layer, thereby forming holes such as via holes and through holes in the insulating layer. Step (III) may be performed using, for example, a drill, laser, plasma, etc., depending on the composition of the resin composition used to form the insulating layer. The dimensions and shape of the holes may be determined appropriately depending on the design of the printed wiring board.

Step (IV) is a step in which the insulating layer is roughened. Typically, smear removal (desmearing) is also performed in this step (IV). The roughening treatment procedures and conditions are not particularly limited, and known procedures and conditions commonly used in forming insulating layers for printed wiring boards can be used. For example, the insulating layer can be roughened by performing a swelling treatment using a swelling liquid, a roughening treatment using an oxidizing agent, and a neutralization treatment using a neutralizing liquid, in that order.

The swelling liquid used in the roughening treatment is not particularly limited, but examples include alkaline solutions and surfactant solutions. Alkaline solutions are preferred, with sodium hydroxide and potassium hydroxide solutions being more preferred. Commercially available swelling liquids include "Swelling Dip Securigans P" and "Swelling Dip Securigans SBU" manufactured by Atotech Japan. The swelling treatment using a swelling liquid is not particularly limited, but can be carried out by immersing the insulating layer in a swelling liquid at 30°C to 90°C for 1 to 20 minutes, for example. To keep swelling of the resin in the insulating layer to an appropriate level, it is preferable to immerse the insulating layer in a swelling liquid at 40°C to 80°C for 5 to 15 minutes.

The oxidizing agent used in the roughening treatment is not particularly limited, but examples include alkaline permanganate solutions prepared by dissolving potassium permanganate or sodium permanganate in an aqueous solution of sodium hydroxide. Roughening treatment using an oxidizing agent such as alkaline permanganate solution is preferably carried out by immersing the insulating layer in an oxidizing agent solution heated to 60°C to 100°C for 10 to 30 minutes. The concentration of permanganate in the alkaline permanganate solution is preferably 5% to 10% by mass. Commercially available oxidizing agents include alkaline permanganate solutions such as "Concentrate Compact CP" and "Dosing Solution Securigance P" manufactured by Atotech Japan.

The neutralizing solution used in the roughening treatment is preferably an acidic aqueous solution, and a commercially available product such as "Reduction Solution Securigant P" manufactured by Atotech Japan is one example.

Treatment with a neutralizing solution can be carried out by immersing the surface that has been roughened with an oxidizing agent in a neutralizing solution at 30°C to 80°C for 5 to 30 minutes. From the standpoint of workability, etc., it is preferable to immerse the object that has been roughened with an oxidizing agent in a neutralizing solution at 40°C to 70°C for 5 to 20 minutes.

Step (V) is a step of forming a conductor layer on an insulating layer. Step (V) may be performed in the same manner as step (6) described in relation to the method for manufacturing a semiconductor chip package.

The thickness of the conductor layer depends on the desired printed wiring board design, but is generally between 3 μm and 35 μm, preferably between 5 μm and 30 μm.

The conductor layer may also be formed using metal foil. When forming the conductor layer using metal foil, it is preferable to perform step (V) between steps (I) and (II). For example, after step (I), the support is removed and metal foil is laminated on the exposed surface of the resin composition layer. The resin composition layer and metal foil may be laminated using a vacuum lamination method. The lamination conditions may be the same as those described for step (I). Next, step (II) is performed to form an insulating layer. Thereafter, a conductor layer having the desired wiring pattern can be formed using the metal foil on the insulating layer using conventional techniques such as a subtractive method or a modified semi-additive method.

Metal foil can be manufactured by known methods such as electrolysis and rolling. Commercially available metal foils include HLP foil and JXUT-III foil manufactured by JX Nippon Mining & Metals Corporation, and 3EC-III foil and TP-III foil manufactured by Mitsui Mining & Smelting Co., Ltd.

Alternatively, as mentioned above, if a metal foil or a metal foil with a supporting substrate is used as the support for the resin sheet, the conductor layer may be formed using the metal foil.

[Semiconductor device]
The semiconductor device of the present invention includes a layer made of a cured product of the resin composition of the present invention. The semiconductor device of the present invention can be produced using the semiconductor chip package or printed wiring board of the present invention.

Semiconductor devices include various semiconductor devices used in electrical appliances (e.g., computers, mobile phones, digital cameras, and televisions) and vehicles (e.g., motorcycles, automobiles, trains, ships, and aircraft).

The present invention will be explained in more detail below using examples. The present invention is not limited to these examples. In the following, "parts" and "%" used to express amounts mean "parts by mass" and "% by mass," respectively, unless otherwise specified.

Example 1: Preparation of Polyester Resin (1) A 0.5-liter four-necked round flask equipped with a stirrer, thermometer, dropping funnel, and nitrogen gas inlet was charged with 33 g of dicyclopentadiene-phenol polyadduct (JFE Chemical Corporation's "J-DPP85," hydroxyl equivalent: 165 g/eq.) as an aromatic hydroxy compound, 14.4 g of 1-naphthol, 30.5 g of isophthalic acid chloride as a halide compound, 0.39 g of an interphase transfer catalyst, and 130 g of cyclopentyl methyl ether as a reaction solvent (chloride group:aromatic hydroxy group = 0.3 mol:0.3 mol). The contents were stirred while blowing in nitrogen gas to completely dissolve the contents. At 30°C, 60.0 g of a 20% aqueous NaOH solution was added dropwise over 1 hour, taking care to avoid heat generation, so that the temperature would ultimately rise to 60°C. After further stirring at 60°C for 2 hours, 50 g of distilled water was added to completely dissolve the by-product inorganic salts. The resulting solution was then transferred to a separatory funnel and allowed to stand for separation, with the lower layer (aqueous layer) being discarded. After three repeated water washes to completely neutralize the solution, the solution was dehydrated by azeotropic distillation and microfiltered. The resulting solution was vacuum distilled at 200°C to remove the solvent, yielding 56 g of the target polyester resin (1).

Examples 2 to 8 Production of Polyester Resins (2) to (8) Polyester resins (2) to (8) were produced in the same manner as in Example 1, except that the reaction solvent, acid halide compound, and aromatic hydroxy compound were changed to the types shown in Table 1. The acid halide compound and aromatic hydroxy compound were used in amounts such that the halide group:aromatic hydroxy group ratio was 0.3 mol:0.3 mol (the aromatic hydroxy group derived from the monovalent aromatic hydroxy compound was 0.1 mol, and the aromatic hydroxy group derived from the divalent aromatic hydroxy compound was 0.2 mol), and the amount of reaction solvent added was approximately 167% by mass relative to 100% by mass of the total amount of the acid halide compound and aromatic hydroxy compound.

Comparative Examples 1 to 4: Production of Polyester Resins (C1) to (C4) Polyester resins (C1) to (C4) were produced in the same manner as in Example 1, except that the reaction solvent, acid halide compound, and aromatic hydroxy compound were changed to the types shown in Table 2. The acid halide compound and aromatic hydroxy compound were used in amounts such that the ratio of halide groups to aromatic hydroxy groups was 0.3 mol:0.3 mol (the aromatic hydroxy groups were 0.1 mol derived from monovalent aromatic hydroxy compounds and 0.2 mol derived from divalent aromatic hydroxy compounds), and the amount of reaction solvent added was approximately 167% by mass relative to 100% by mass of the total amount of the acid halide compound and aromatic hydroxy compounds.

In the examples and comparative examples, the oil-water separation properties after the condensation reaction (when the mixture was left to stand in a separatory funnel for separation) were evaluated according to the following criteria:

Evaluation criteria for oil-water separation:
○: The organic layer and the aqueous layer are clearly separated. △: The organic layer or the aqueous layer becomes cloudy, and separation takes time. ×: The entire layer becomes an emulsion, making separation difficult.

For polyester resins (1) to (8), a varnish-like resin composition was prepared by dissolving 22 parts of the polyester resin, 27 parts of epoxy resin ("NC3000" manufactured by Nippon Kayaku Co., Ltd.), 74 parts of inorganic filler ("SC4050-SX" manufactured by Admatechs Co., Ltd.), and 0.6 parts of crosslinking accelerator (4-dimethylaminopyridine (DMAP)) in 45 parts of solvent. Cyclopentyl methyl ether, cyclohexyl methyl ether, or 4-methyltetrahydropyran was used as the solvent.

The obtained resin composition was applied to a support (polyethylene terephthalate film, thickness 38 μm) using a die coater so that the thickness of the resin composition layer after drying would be 40 μm, and then dried at 120° C. for 2 minutes to produce a resin sheet. This enabled the production of a resin sheet having a resin composition layer with good coatability and a uniform thickness.

Claims (22)

A method for producing a polyester resin, in which one or more solvents A selected from the group consisting of cycloalkyl alkyl ethers and alkyltetrahydropyrans are used as the reaction solvent in the condensation reaction of an acid halide compound and an aromatic hydroxy compound. The method for producing a polyester resin according to claim 1, wherein the polyester resin contains an active ester group. The method for producing a polyester resin according to claim 1 or 2, wherein the acid halide compound is divalent and the aromatic hydroxy compound is a mixture of monovalent and divalent aromatic hydroxy compounds. The method for producing a polyester resin according to claim 1 or 2, wherein the acid halide compound is a mixture of monovalent and divalent compounds, and the aromatic hydroxy compound is divalent. A method for producing a polyester resin according to any one of claims 1 to 4, wherein the molar ratio of halide groups to aromatic hydroxy groups is in the range of 1.00:0.80 to 1.00:1.20. The method for producing a polyester resin according to any one of claims 1 to 5, wherein the polyester resin contains an average of 2 to 10 active ester groups per molecule. The method for producing a polyester resin according to any one of claims 1 to 6, wherein the boiling point of solvent A is in the range of 70 to 150°C. The method for producing a polyester resin according to any one of claims 1 to 7, wherein the cycloalkyl alkyl ether is represented by the following formula (1), and the alkyl tetrahydropyran is represented by the following formula (2):
(In the formula,
R11 represents a cycloalkyl group having 3 to 10 carbon atoms;
R12 represents an alkyl group having 1 to 6 carbon atoms.
(In the formula,
R21 represents an alkyl group having 1 to 6 carbon atoms. The method for producing a polyester resin according to any one of claims 1 to 8, wherein solvent A contains cyclopentyl methyl ether, cyclohexyl methyl ether, or 4-methyltetrahydropyran. The method for producing a polyester resin according to any one of claims 1 to 9, wherein the amount of solvent A added is 30 to 500% by mass, relative to 100% by mass of the total amount of the acid halide compound and aromatic hydroxy compound. The following steps (1) to (4):
(1) a step of dissolving an acid halide compound and an aromatic hydroxy compound in one or more solvents A selected from the group consisting of cycloalkyl alkyl ethers and alkyltetrahydropyrans to obtain a solution;
(2) adding a dehydrohalogenating agent to the solution to carry out a condensation reaction;
The method for producing the polyester resin according to any one of claims 1 to 10, further comprising: (3) a step of adding water after the condensation reaction to separate the oil and water, thereby discharging the by-product salt from the system; and (4) a step of purifying the polyester resin by further washing with water and separating the oil and water. The following steps (5) and (6):
The method for producing a polyester resin according to claim 11, further comprising: (5) a step of dehydrating the mixture to precipitate a by-product salt; and (6) a step of removing the by-product salt by filtration. A resin crosslinking agent containing a polyester resin obtained by the manufacturing method described in any one of claims 1 to 12 and solvent A used as a reaction solvent. A resin composition comprising a polyester resin obtained by the manufacturing method described in any one of claims 1 to 12, solvent A used as a reaction solvent, and a crosslinkable resin. The resin composition according to claim 14 , further comprising an inorganic filler. The resin composition according to claim 14 or 15, which is used for an insulating layer of a printed wiring board. The resin composition according to claim 14 or 15, which is used for semiconductor encapsulation. A sheet-like laminate material comprising the resin composition according to any one of claims 14 to 17 . A printed wiring board comprising an insulating layer made of a cured product of the resin composition according to any one of claims 14 to 16 . A semiconductor chip package comprising an encapsulating layer made of a cured product of the resin composition according to any one of claims 14 to 15 and 17 . 21. The semiconductor chip package of claim 20 , which is a fan-out type package. A semiconductor device comprising the printed wiring board according to claim 19 or the semiconductor chip package according to claim 20 or 21 .