CN114040843A

CN114040843A - Laminate, cured product, and electronic component

Info

Publication number: CN114040843A
Application number: CN202080047080.XA
Authority: CN
Inventors: 矢本和久; 青山良朋; 宫部英和
Original assignee: Taiyo Ink Mfg Co Ltd
Current assignee: Taiyo Holdings Co Ltd
Priority date: 2019-06-27
Filing date: 2020-06-23
Publication date: 2022-02-11
Also published as: TW202110930A; WO2020262405A1; KR20220024430A; JPWO2020262405A1

Abstract

Providing: and a laminate comprising an extra thin copper foil and a resin layer, which is excellent in laser drilling processability and reflow resistance, and in which a cured product of the resin layer has a low dielectric loss tangent. The laminate is characterized by comprising, in order, at least: a carrier foil, an extra thin copper foil having a thickness of 0.1 to 6 μm, and a resin layer, wherein the resin layer comprises: (A) an epoxy resin, (B) a compound having an active ester group, and (C) an inorganic filler.

Description

Laminate, cured product, and electronic component

Technical Field

The invention relates to a laminate, a cured product and an electronic component.

Background

As a material for forming electronic parts such as printed wiring boards, Resin-Coated copper foil (RCC) is known as a laminate of a copper foil and a curable Resin layer (for example, patent document 1). As a copper foil with resin which has been used conventionally, a copper foil having a curable resin layer prepared by coating an epoxy resin composition on a copper foil is widely known.

In order to further miniaturize circuit patterns in recent years, MSAP (Modified Semi-Additive Process) is often applied instead of the conventional subtraction method. For example, the following methods are used: the resin-coated copper foil is laminated by heat lamination and heat curing so that the resin layer side is in contact with a circuit board on which a circuit pattern is formed, and then laser processing, desmear processing, plating processing, and the like are performed to manufacture a laminated circuit board.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2006-89595

Disclosure of Invention

Problems to be solved by the invention

When a circuit is formed by using a copper foil with resin by the above-described manufacturing method, there is a problem that defects such as swelling are likely to occur at the time of solder reflow. Further, as the copper foil of the resin-coated copper foil is thinner, such a defect at the time of solder reflow becomes more remarkable.

When the copper foil is made thick to suppress defects in solder reflow, laser processing becomes difficult. Therefore, it has been studied to first thicken the copper foil with the resin-attached copper foil, or to thermally press-bond the resin-attached copper foil and then to form a thin film of the copper foil with an etching solution, followed by laser processing. However, it is difficult to form a thin film with a uniform thickness, and therefore, if the hole forming process is performed by laser, there is a problem that the opening diameter becomes non-uniform.

In recent years, high-speed communication, that is, transmission loss tends to increase with higher frequencies, and thus materials for electronic components are also required to have low dielectric loss tangents that can suppress transmission loss.

Accordingly, an object of the present invention is to provide: a laminate having an extra thin copper foil and a resin layer, which is excellent in laser drilling processability and reflow resistance and in which a cured product of the resin layer has a low dielectric loss tangent, a cured product of the resin layer of the laminate, and an electronic component having the cured product.

Means for solving the problems

The present inventors have made intensive studies to achieve the above object, and as a result, have found that: the above object can be achieved by providing a resin layer containing an epoxy resin, a compound having an active ester group, and an inorganic filler on an extra thin copper foil with a carrier foil, and the invention has been completed.

That is, the laminate of the present invention is characterized by comprising, in order, at least: a carrier foil, an extra thin copper foil having a thickness of 0.1 to 6 μm, and a resin layer, wherein the resin layer comprises: (A) an epoxy resin, (B) a compound having an active ester group, and (C) an inorganic filler.

In the laminate of the present invention, the ratio of the total amount of epoxy groups of the epoxy resin (a) to the total amount of active ester groups of the compound having an active ester group (B) in the resin layer is preferably 0.20 to 0.60.

In the laminate of the present invention, the amount of the inorganic filler (C) is preferably 50% by mass or more, based on 100% by mass of nonvolatile components in the resin layer.

In the laminate of the present invention, it is preferable that the compound (B) having an active ester group is a compound represented by the following general formula (1),

(in the formula, X₁Each independently a group having a benzene ring or a naphthalene ring, k represents 0 or 1, and n is 0.25 to 1.5 on the average of the repeating units. ).

In the laminate of the present invention, it is preferable that the compound (B) having an active ester group is a compound having a structure having a structural site represented by the following general formula (2) and having an aryloxy group having one valence at both ends,

(in the formula (2), X₂Each independently is a group represented by the following formula (3) or a group represented by the following formula (4),

m is an integer of 1 to 6, n is each independently an integer of 1 to 5, q is each independently an integer of 1 to 6,

in the formula (3), k is an integer of 1 to 5,

in the formula (4), Y is a group represented by the formula (3) (k is an integer of 1 to 5 independently) and t is an integer of 0 to 5 independently).

In the laminate of the present invention, the ratio of the total amount of epoxy groups of the epoxy resin (a) to the total amount of active ester groups of the compound having an active ester group (B) in the resin layer is preferably 0.20 to 0.50.

In the laminate of the present invention, the dielectric loss tangent of the cured product of the resin layer is preferably 0.01 or less.

The electronic component of the present invention is characterized by having a cured product obtained by curing the resin layer of the laminate.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, there can be provided: a laminate having an extra thin copper foil and a resin layer, which is excellent in laser drilling processability and reflow resistance and in which a cured product of the resin layer has a low dielectric loss tangent, a cured product of the resin layer of the laminate, and an electronic component having the cured product.

Drawings

Fig. 1 is a schematic cross-sectional view showing one embodiment of a laminate according to the present invention.

Detailed Description

The laminate of the present invention is characterized by comprising, in order, at least: a carrier foil, an extra thin copper foil having a thickness of 0.1 to 6 μm, and a resin layer, wherein the resin layer comprises: (A) an epoxy resin, (B) a compound having an active ester group, and (C) an inorganic filler. Since the carrier foil is supported by the extremely thin copper foil, the handling property is excellent, and the production of the laminate and the lamination of the laminate are facilitated. Further, thinning of the copper foil by etching after thermocompression bonding, which causes unevenness in film thickness, is not necessary, and thus laser drilling workability is also excellent. Further, by combining an extra thin copper foil having a thickness of 0.1 to 6 μm with a resin layer containing the components (A) to (C), a cured product having excellent reflow resistance and a low dielectric loss tangent can be obtained. In the present specification, when the surface of the extra thin copper foil is roughened, the uneven portion is not included in the thickness. In other words, the thickness of the extra thin copper foil when the extra thin copper foil is subjected to the roughening treatment is also the thickness of the portion excluding the irregularities of the roughened surface, that is, the main body (base) portion excluding the contour of the roughened surface.

Fig. 1 is a schematic cross-sectional view showing one embodiment of a laminate according to the present invention. The laminate 1 is formed by laminating a carrier foil 2, an extra thin copper foil 3, and a resin layer 4 in this order.

In the laminate of the present invention, the ratio of the total amount of epoxy groups in the epoxy resin (a)/the total amount of active ester groups in the compound having an active ester group (B) in the resin layer is preferably 0.20 to 0.60, and a cured product having both high heat resistance and low dielectric loss tangent and a low linear thermal expansion coefficient can be obtained. It is generally considered that, if a compound having an active ester group is blended in a large amount, the crosslinking density of the cured product decreases, the glass transition temperature (Tg) of the cured product decreases, and the heat resistance deteriorates, and therefore, in general, a compound having an active ester group is blended in an excessive amount not exceeding the epoxy equivalent of the epoxy resin in the composition. As a result, a cured product having excellent reflow resistance and a low dielectric loss tangent can be obtained.

The detailed mechanism is not clear, but it is believed that: if the proportion of the compound having an active ester group, preferably the compound having an active ester group having a structure of the following general formula (1) or (2), is increased, the structure of the active ester, that is, the volume ratio of the rigid aromatic ester structure having a high molecular orientation becomes large, and the movement of the chain portion between the crosslinking points is controlled, and therefore, the glass transition temperature is improved. The total amount of epoxy groups in the epoxy resin (a) can be determined by dividing the amount of epoxy resin (a) contained in the composition by the epoxy equivalent of the epoxy resin (a). The total amount of active ester groups in the compound having an active ester group (B) can be determined by dividing the amount of the compound having an active ester group (B) contained in the composition by the active ester equivalent of the compound having an active ester group (B). The upper limit of the total amount ratio is preferably 0.50 or less, more preferably 0.40 or less, and particularly preferably 0.30 or less, from the viewpoint that a cured product having a lower dielectric loss tangent can be obtained.

The resin layer, the extra thin copper foil and the carrier foil included in the laminate of the present invention will be described below. In the present specification, when a numerical range is denoted by "-" in this specification, the range includes these numerical values (i.e.,. cndot. cng.), the like).

[ resin layer ]

The resin layer includes: (A) an epoxy resin, (B) a compound having an active ester group, and (C) an inorganic filler. The resin layer can be obtained by applying and drying a resin composition containing (a) an epoxy resin, (B) a compound having an active ester group, and (C) an inorganic filler.

[ (A) epoxy resin ]

(A) The epoxy resin is a resin having an epoxy group, and any of the conventionally known epoxy resins can be used. Examples thereof include a 2-functional epoxy resin having 2 epoxy groups in the molecule, a polyfunctional epoxy resin having a plurality of epoxy groups in the molecule, and the like. The epoxy resin may be a hydrogenated 2-functional epoxy resin. The epoxy resin (a) may be any of a solid epoxy resin, a semisolid epoxy resin, and a liquid epoxy resin. In the present specification, a solid epoxy resin means an epoxy resin that is solid at 40 ℃, a semisolid epoxy resin means an epoxy resin that is solid at 20 ℃ and liquid at 40 ℃, and a liquid epoxy resin means an epoxy resin that is liquid at 20 ℃. The judgment of the liquid state was carried out according to "method for confirming liquid state" in appendix 2 of the provincial directive (No. 1 of the "national self-governing" year) on the test and properties of dangerous materials. For example, the method described in paragraphs 23 to 25 of Japanese patent application laid-open No. 2016-079384. (A) The epoxy resin may be used alone in 1 kind, or may be used in combination with 2 or more kinds.

In the present invention, as described above, the ratio of the total amount of epoxy groups in the (a) epoxy resin/(the total amount of active ester groups in the (B) compound having active ester groups in the resin layer is preferably 0.20 to 0.60, and in this case, the (a) epoxy resin preferably contains at least either of a liquid epoxy resin having 3 or more functions and a semisolid epoxy resin having 3 or more functions. When the epoxy resin composition contains a liquid epoxy resin having 3 or more functions and a semi-solid epoxy resin having 3 or more functions, the glass transition temperature can be improved while maintaining the dielectric loss tangent at a low level. As a commercially available product of such a 3-or higher-functional liquid epoxy resin, TEPIC-VL available from Nissan Chemical Co., Ltd., JeR630 available from Mitsubishi Chemical Corporation, etc. can be used. As a commercial product of such a semi-solid epoxy resin having 3 or more functions, for example, jER604 manufactured by Mitsubishi Chemical Corporation and the like can be used.

The epoxy equivalent of the epoxy resin (A) is preferably 100 to 5000g/eq, more preferably 150 to 3000g/eq. For example, the epoxy resin (A) may contain a liquid or semisolid epoxy resin having an epoxy equivalent of 350 to 1000g/eq.

(A) The epoxy resin is not limited to the above, and examples of the solid epoxy resin include: naphthalene type epoxy resins such as EPICLON HP-4700 manufactured by DIC corporation, naphthalene skeleton-containing novolak type epoxy resins such as NC-7000 manufactured by Nippon Kabushiki Kaisha, naphthol aralkyl type epoxy resins such as ESN-475V manufactured by Nikko chemical & materials Co., Ltd; an epoxide (trisphenol type epoxy resin) of a condensate of a phenol such as EPPN-502H and an aromatic aldehyde having a phenolic hydroxyl group, manufactured by Nippon Kagaku K.K.; a dicyclopentadiene type epoxy resin such as EPICLON HP-7200H available from DIC; biphenyl aralkyl type epoxy resins such as NC-3000H, NC-3000L manufactured by Nippon chemical Co., Ltd; novolac type epoxy resins such as EPICLON 680 manufactured by DIC and EOCN-104S manufactured by Nippon Kabushiki Kaisha; biphenyl type epoxy resins such as YX-4000 manufactured by Mitsubishi Chemical Corporation; phosphorus-containing epoxy resins such as TX0712 manufactured by ri-fe chemical & materials corporation; tris (2, 3-epoxypropyl) isocyanurate such as TEPIC manufactured by Nissan chemical Co. By containing the solid epoxy resin, the glass transition temperature of the cured product becomes high, and the heat resistance is excellent. When the ratio of the total amount of epoxy groups in the epoxy resin (a)/the total amount of active ester groups in the compound having active ester groups (B) in the resin layer is 0.20 to 0.60, an aralkyl type epoxy resin such as ESN-475V, NC3000H, that is, an epoxy resin having a 2-valent group in which an alkylene group and an arylene group are bonded is preferable in terms of obtaining a cured product having a higher Tg, excellent reflow resistance, and a low dielectric loss tangent in the solid epoxy resin. Examples of the alkylene group include a methylene group, a methylmethylene group, an ethylene group, a propylene group, and a trimethylene group. Examples of the arylene group include a phenylene group, a biphenylene group, and a naphthylene group.

Examples of the semisolid epoxy resin include: bisphenol A type epoxy resins such as EPICLON860, EPICLON900-IM, EPICLON EXA-4816, EPICLON EXA-4822, Epotote YD-134 made by Nippon Chemical & materials, jER834 and jER872 made by Mitsubishi Chemical Corporation, and ELA-134 made by Sumitomo Chemical Co., Ltd; naphthalene epoxy resins such as EPICLON HP-4032 available from DIC; phenol novolac type epoxy resins such as EPICLON-740 manufactured by DIC Corporation, and aromatic amino epoxy resins such as JeR604 manufactured by Mitsubishi Chemical Corporation. By including the semi-solid epoxy resin, the glass transition temperature (Tg) of the cured product is high, the linear thermal expansion Coefficient (CTE) is low, and the crack resistance is excellent. By including the semisolid epoxy resin, the dry film has excellent storage stability and can be prevented from cracking or peeling.

Examples of the liquid epoxy resin include aromatic amino epoxy resins such as bisphenol a type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin, phenol novolac type epoxy resin, t-butyl-catechol type epoxy resin, glycidylamine type epoxy resin, and aminophenol type epoxy resin, alicyclic epoxy resin, and heterocyclic epoxy resin. By containing the liquid epoxy resin, the laminate has excellent flexibility.

(A) The epoxy resin is preferably a solid epoxy resin and at least either one of a liquid epoxy resin and a semi-solid epoxy resin is used. In addition, solid epoxy resin, liquid epoxy resin and semisolid epoxy resin can also be used together.

The amount of the epoxy resin (a) is preferably 50% by mass or less, more preferably 40% by mass or less, and particularly preferably 30% by mass or less, from the viewpoint that a cured product having a lower dielectric loss tangent can be obtained when the nonvolatile content in the resin layer is 100% by mass. From the viewpoint of the strength of the cured product, the lower limit is preferably 1% by mass or more, and more preferably 3% by mass or more.

The resin layer of the laminate of the present invention may contain (a) a thermosetting resin other than the epoxy resin within a range not impairing the effects of the present invention, and for example, a known and commonly used thermosetting resin such as an isocyanate compound, a blocked isocyanate compound, an amino resin, a benzoxazine resin, a carbodiimide resin, a cyclic carbonate compound, a polyfunctional oxetane compound, an episulfide resin, a maleimide resin, or the like may be used.

[ (B) Compounds having an active ester group ]

(B) The compound having an active ester group is preferably a compound having 2 or more active ester groups in one molecule. The compound having an active ester group can be usually obtained by a condensation reaction of a carboxylic acid compound and a hydroxyl compound. Among them, a compound having an active ester group obtained by using a phenol compound or a naphthol compound as a hydroxyl compound is preferable. Examples of the phenol compound or naphthol compound include hydroquinone, resorcinol, bisphenol a, bisphenol F, bisphenol S, phenolphthalein, methylated bisphenol a, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α -naphthol, β -naphthol, 1, 5-dihydroxynaphthalene, 1, 6-dihydroxynaphthalene, 2, 6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucinol, benzenetriol, dicyclopentadienyl diphenol, phenol novolak and the like. The compound having an active ester group (B) may be a naphthalenediol alkyl/benzoic acid type. (B) The compound having an active ester group may be used alone in 1 kind, or may be used in combination with 2 or more kinds. The compound having an active ester group (B) is preferably any of benzene, α -naphthol, β -naphthol, and dicyclopentadiene skeleton.

The upper limit of the amount of the compound having an active ester group (B) is preferably 50 mass% or less, more preferably 45 mass% or less, and particularly preferably 40 mass% or less, from the viewpoint of the strength of the cured product, when the nonvolatile content in the resin layer is 100 mass%. The lower limit is preferably 5% by mass or more, more preferably 10% by mass or more, from the viewpoint that a cured product having a lower dielectric loss tangent can be obtained.

(B) Among the compounds having an active ester group, the compounds having an active ester group described below as (B1) and (B2) can be suitably used. The compound having an active ester group (B2) is more preferable because the dielectric loss tangent of the cured product can be further reduced.

(B1)

(B1) The compound having an active ester group of (b) has a structure obtained by reacting (b1) a phenol resin having a molecular structure in which phenols are linked via an aliphatic cyclic hydrocarbon group, (b2) an aromatic dicarboxylic acid or a halide thereof, and (b3) an aromatic monohydroxy compound. Preferably, the phenolic resin has a structure obtained by reacting 0.05 to 0.75 mol of the phenolic hydroxyl group in the (b1) phenolic resin and 0.25 to 0.95 mol of the (b3) aromatic monohydroxy compound with respect to 1 mol of the carboxyl group or acid halide group in the (b2) aromatic dicarboxylic acid or its halide.

In the phenolic resin (b1), the molecular structure in which phenols are linked via an aliphatic cyclic hydrocarbon group is a structure obtained by addition polymerization of an unsaturated aliphatic cyclic hydrocarbon compound having 2 double bonds in 1 molecule and phenols. Examples of the phenols include phenol and substituted phenols substituted with 1 or more alkyl, alkenyl, allyl, aryl, aralkyl, halogen groups, or the like. Specifically, cresol, xylenol, ethylphenol, isopropylphenol, butylphenol, octylphenol, nonylphenol, vinylphenol, isopropenylphenol, allylphenol, phenylphenol, benzylphenol, chlorophenol, bromophenol, naphthol, dihydroxynaphthalene, and the like can be exemplified, but not limited thereto. Also mixtures thereof may be used. Among them, phenol is particularly preferable in view of excellent fluidity and curability.

Specific examples of the unsaturated alicyclic cyclic hydrocarbon compound include dicyclopentadiene, tetrahydroindene, 4-vinylcyclohexene, 5-vinylnorbornen-2-ene, α -pinene, β -pinene, and limonene. Among them, dicyclopentadiene is preferable from the viewpoint of the balance of characteristics, particularly heat resistance and hygroscopicity. Furthermore, dicyclopentadiene is contained in petroleum fractions, and therefore industrial dicyclopentadiene may contain other aliphatic or aromatic dienes as impurities, but considering heat resistance, curability, moldability, etc., a product having a purity of 90 mass% or more of dicyclopentadiene is desired.

Next, the aromatic dicarboxylic acid or halide thereof (b2) includes aromatic dicarboxylic acids such as isophthalic acid, terephthalic acid, 1,4-, 2,3-, or 2, 6-naphthalenedicarboxylic acid, and acid halides such as acid fluorides, acid chlorides, acid bromides, and acid iodides thereof. Among them, particularly, in view of good reactivity, preferred are acid chlorides of aromatic dicarboxylic acids, among them, preferred are dichlorides of isophthalic acid and dichlorides of terephthalic acid, and particularly preferred is dichlorides of isophthalic acid.

Next, examples of the aromatic monohydroxy compound include phenol; alkylphenols such as o-cresol, m-cresol, p-cresol, and 3, 5-xylenol; aralkyl phenols such as o-phenylphenol, p-phenylphenol, 2-benzylphenol, 4-benzylphenol, and 4- (. alpha. -cumyl) phenol; naphthols such as α -naphthol and β -naphthol. Among these, α -naphthol and β -naphthol are particularly preferable because the dielectric loss tangent of the cured product is low.

(B1) The active ester compound has a structure obtained by reacting (b1) a phenol resin, (b2) an aromatic dicarboxylic acid or a halide thereof, and (b3) an aromatic monohydroxy compound, and particularly preferably has a structure represented by the following general formula (1) in terms of a low dielectric loss tangent of a cured product and a low solution viscosity when dissolved in an organic solvent,

(in the formula, X₁Is a group having a benzene ring or a naphthalene ring, k represents 0 or 1, and n is 0.05 to 2.5 in terms of the average value of the repeating units. ).

The group having a benzene ring or a naphthalene ring is not particularly limited, and may be a phenyl group, a naphthyl group or the like, or a benzene ring or a naphthalene ring may be bonded to a molecular terminal via another atom and may optionally have a substituent. In addition, the (B1) active ester compound preferably has a naphthalene ring at the molecular terminal thereof.

In particular, the value of n in the general formula (1), that is, the average value of the repeating units is preferably in the range of 0.25 to 1.5 from the viewpoint of low solution viscosity and easy production of a laminate. In the general formula (1), the value of k is preferably 0 from the viewpoint of high heat resistance and low dielectric loss tangent.

Here, n in the above general formula (1) can be obtained as follows.

[ solving method of n in the general formula (1) ]

By GPC measurement performed under the following conditions, ratios (β 1/α 1, β 2/α 2, β 3/α 3, and β 4/α 4) of styrene-converted molecular weights (α 1, α 2, α 3, and α 4) to theoretical molecular weights (β 1, β 2, β 3, and β 4) of n 1, n 2, n 3, and n 4, respectively, were obtained, and an average value of (β 1/α 1 to β 4/α 4) of these values was obtained. The average molecular weight is a number obtained by multiplying the number average molecular weight (Mn) obtained by GPC by the average value. Next, the value of n is calculated using the molecular weight of the general formula (1) as the average molecular weight.

(GPC measurement conditions)

A measuring device: HLC-8220GPC manufactured by Tosoh corporation,

Column: protection column "H XL-L" made by Tosoh corporation "

+ TSK-GEL G2000HXL manufactured by Tosoh corporation "

+ TSK-GEL G3000HXL manufactured by Tosoh corporation "

+ manufactured by Tosoh corporation of "TSK-GEL G4000 HXL"

A detector: RI (differential refractometer)

Data processing: "GPC-8020 model II version 4.10" manufactured by Tosoh corporation "

The measurement conditions were as follows: column temperature 40 deg.C

Tetrahydrofuran as developing solvent

Flow rate 1.0 ml/min

The standard is as follows: the following monodisperse polystyrene having a known molecular weight was used according to the manual of GPC-8020model II version 4.10.

(use of polystyrene)

"A-500" made by Tosoh corporation "

"A-1000" made by Tosoh corporation "

"A-2500" made by Tosoh corporation "

"A-5000" manufactured by Tosoh corporation "

"F-1" made by Tosoh corporation "

"F-2" made by Tosoh corporation "

"F-4" made by Tosoh corporation "

"F-10" made by Tosoh corporation "

"F-20" made by Tosoh corporation "

"F-40" made by Tosoh corporation "

"F-80" made by Tosoh corporation "

"F-128" made by Tosoh corporation "

Sample preparation: a tetrahydrofuran solution (1.0 mass% in terms of solid content of the resin) was filtered through a microfilter (50. mu.l).

Specifically, the method of reacting the (b1) phenol resin, the (b2) aromatic dicarboxylic acid or a halide thereof, and the (b3) aromatic monohydroxy compound may be a method of reacting these respective components in the presence of a base catalyst.

Examples of the base catalyst that can be used here include sodium hydroxide, potassium hydroxide, triethylamine, pyridine, and the like. Among them, sodium hydroxide and potassium hydroxide are particularly preferable because they can be used in the form of an aqueous solution and yield is good.

The reaction may be carried out by the following method: in the presence of an organic solvent, (b1) a phenol resin, (b2) an aromatic dicarboxylic acid or a halide thereof, and (b3) an aromatic monohydroxy compound are mixed and reacted while continuously or intermittently adding dropwise the above-mentioned basic catalyst or an aqueous solution thereof. In this case, the concentration of the aqueous solution of the alkali catalyst is preferably in the range of 3.0 to 30%. Examples of the organic solvent that can be used here include toluene and dichloromethane.

After the reaction is completed, when an aqueous solution of an alkali catalyst is used, the reaction solution is allowed to stand for liquid separation, the aqueous layer is removed, and the remaining organic layer is repeatedly washed until the washed aqueous layer becomes substantially neutral, whereby the target resin can be obtained.

Since the compound having an active ester group of (B1) thus obtained is usually obtained as an organic solvent solution, the compound can be directly mixed with other compounding ingredients, and the amount of the organic solvent can be appropriately adjusted to produce the desired curable resin composition. The active ester compound of (B1) is characterized by having a low melt viscosity when dissolved in an organic solvent to form a resin solution, specifically, an active ester resin having a toluene solution of 65% nonvolatile content and a solution viscosity of 300 to 10000 mPas (25 ℃).

(B2)

(B2) The compound having an active ester group of (2) is a compound having a resin structure having a structural site represented by the following general formula (2) and having an aryloxy group having one valence at both ends thereof,

m is an integer of 1 to 6, n is each independently an integer of 1 to 5, q is each independently an integer of 0 to 6, k is each independently an integer of 1 to 5 in formula (3), Y is a group represented by the above formula (3) (k is each independently an integer of 1 to 5), t is each independently an integer of 0 to 5)

(B2) In the compound having an active ester group (2), the partial structure represented by the general formula (2) is preferably a structure derived from a modified naphthalene compound having a hydroxyl group equivalent of 170 to 200g/eq.

In the formula (2), in order to clarify the relationship between m and n, the following embodiments are given, but the active ester resin (B2) is not limited to these.

For example, when m is 1, formula (2) represents the structure of formula (2-I) below.

In the formula (2-I), n is an integer of 1 to 5, and q is an integer of 0 to 6 independently. Similarly to the relationship between m and n, when n is 2 or more for q, each q independently represents an integer of 0 to 6.

In addition, for example, when m is 2, formula (2) represents a structure of formula (2-II) below.

In the formula (2-II), n is an integer of 1-5, and q is an integer of 0-6. Similarly to the relationship between m and n, when n is 2 or more for q, each q independently represents an integer of 0 to 6.

(B2) The compound having an active ester group of (a) has a naphthylene ether structural site in a main molecular skeleton, and therefore, can impart more excellent heat resistance and flame retardancy to a cured product, and the structural site has a structure in which the following structural sites are bonded, and therefore, the cured product can achieve more excellent dielectric characteristics.

In addition, in the resin structure of the compound having an active ester group of (B2), a structure having aryloxy groups as both terminals is formed, and thus, in the application to a multilayer printed board, it is possible to obtain a sufficiently high improvement in the thermal decomposition resistance of the cured product.

The compound having an active ester group of (B2) has a softening point preferably in the range of 100 to 200 ℃, particularly preferably in the range of 100 to 190 ℃, from the viewpoint of excellent heat resistance of a cured product.

(B2) In the compound having an active ester group in (2), m in the formula (2) is an integer of 1 to 6. Among them, m is preferably an integer of 1 to 5. In addition, n in the formula (2) is an integer of 1 to 5 independently. Among them, n is preferably an integer of 1 to 3.

In the formula (2), when the relationship between m and n is expressed in order to clarify the relationship, for example, when m is an integer of 2 or more, 2 or more n are generated, but in this case, n is an independent value. The same value or different values may be used as long as n is within the numerical range.

(B2) In the compound having an active ester group of (3), in the formula (2), X is 1 or more₂Substituted at any position in the naphthalene ring structure.

Examples of the aryloxy groups at both ends of the resin structure include monophenol compounds derived from phenol, cresol, p-tert-butylphenol (p-t-butyl phenol), 1-naphthol, and 2-naphthol. Among them, phenoxy group, tolyloxy group, and 1-naphthyloxy group are preferable, and 1-naphthyloxy group is more preferable, from the viewpoint of the thermal decomposition resistance of the cured product.

The method for producing the compound having an active ester group of (B2) is described in detail below.

(B2) The method for producing a compound having an active ester group of (2) comprises the steps of: a step of reacting a dihydroxynaphthalene compound with benzyl alcohol in the presence of an acid catalyst to obtain a benzyl-modified naphthalene compound (hereinafter, this step may be abbreviated as "step 1"); next, a step of reacting the obtained benzyl group-modified naphthalene compound with an aromatic dicarboxylic acid chloride and a monophenol compound (hereinafter, this step may be abbreviated as "step 2").

That is, first, in step 1, the dihydroxy naphthalene compound and benzyl alcohol are reacted in the presence of an acid catalyst to obtain a benzyl-modified naphthalene compound having a naphthylene structure as a main skeleton, phenolic hydroxyl groups at both ends thereof, and a benzyl group is bonded in a pendant manner to an aromatic core of the naphthylene structure. It is to be noted that, in general, when a dihydroxynaphthalene compound is subjected to naphthylene etherification in the presence of an acid catalyst, it is extremely difficult to adjust the molecular weight, and the molecular weight becomes high, whereas, in the above production method, the use of benzyl alcohol in combination makes it possible to suppress the increase in molecular weight and to obtain a resin suitable for electronic material applications.

Further, the content of benzyl groups in the intended benzyl group-modified naphthalene compound can be adjusted by adjusting the amount of benzyl alcohol, and the melt viscosity of the benzyl group-modified naphthalene compound itself can also be adjusted. That is, the reaction ratio of the dihydroxy naphthalene compound and benzyl alcohol is usually selected from the range in which the reaction ratio of the dihydroxy naphthalene compound and benzyl alcohol (dihydroxy naphthalene compound)/(benzyl alcohol) is 1/0.1 to 1/10 on a molar basis, and the reaction ratio of the dihydroxy naphthalene compound and benzyl alcohol (dihydroxy naphthalene compound)/(benzyl alcohol) is preferably 1/0.5 to 1/4.0 on a molar basis for the balance between heat resistance, flame retardancy, dielectric properties and thermal decomposition resistance.

Examples of the dihydroxynaphthalene compound that can be used herein include 1, 2-dihydroxynaphthalene, 1, 3-dihydroxynaphthalene, 1, 4-dihydroxynaphthalene, 1, 5-dihydroxynaphthalene, 1, 6-dihydroxynaphthalene, 1, 7-dihydroxynaphthalene, 1, 8-dihydroxynaphthalene, 2, 3-dihydroxynaphthalene, 2, 6-dihydroxynaphthalene, and 2, 7-dihydroxynaphthalene. Among them, 1, 6-dihydroxynaphthalene and 2, 7-dihydroxynaphthalene are preferable, and 2, 7-dihydroxynaphthalene is more preferable, from the viewpoint that the flame retardancy of the cured product of the obtained benzyl-modified naphthalene compound becomes further excellent, the dielectric loss tangent of the cured product also becomes low, and the dielectric characteristics become excellent.

Examples of the acid catalyst that can be used in the reaction of the dihydroxynaphthalene compound and benzyl alcohol in step 1 include inorganic acids such as phosphoric acid, sulfuric acid, and hydrochloric acid, organic acids such as oxalic acid, benzenesulfonic acid, toluenesulfonic acid, methanesulfonic acid, and fluoromethanesulfonic acid, and friedel-crafts catalysts such as aluminum chloride, zinc chloride, tin chloride, iron chloride, and diethylsulfuric acid.

The amount of the acid catalyst to be used may be suitably selected depending on the desired modification ratio, and for example, in the case of an inorganic acid or an organic acid, the amount is in the range of 0.001 to 5.0 parts by mass, preferably 0.01 to 3.0 parts by mass, based on 100 parts by mass of the dihydroxynaphthalene compound, and in the case of a Friedel-crafts catalyst, the amount is preferably 0.2 to 3.0 moles, preferably 0.5 to 2.0 moles, based on 1 mole of the dihydroxynaphthalene compound.

The reaction of the dihydroxynaphthalene compound with benzyl alcohol in step 1 may be carried out in the absence of a solvent, or may be carried out in the presence of a solvent in order to improve the uniformity in the reaction system. Examples of the solvent include ethylene glycol and mono-or diethers of diethylene glycol such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dipropyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, and diethylene glycol monobutyl ether; nonpolar aromatic solvents such as benzene, toluene, and xylene; aprotic polar solvents such as dimethylformamide and dimethylsulfoxide; chlorobenzene, and the like.

A specific method for carrying out the reaction of step 1 may be as follows: the dihydroxy naphthalene compound, the benzyl alcohol and the acid catalyst are dissolved in the absence of a solvent or in the presence of the solvent, and the reaction is carried out at a temperature of about 60 to 180 ℃, preferably about 80 to 160 ℃. The reaction time is not particularly limited, but is preferably 1 to 10 hours. Thus, the reaction can be specifically carried out by maintaining the temperature for 1 to 10 hours. In addition, from the viewpoint of rapid progress of the reaction and improvement of productivity, it is preferable to remove water produced during the reaction by distillation using a fractionating tube or the like to the outside of the system.

When the coloration of the obtained benzyl group-modified naphthalene compound is large, an antioxidant or a reducing agent may be added to the reaction system in order to suppress the coloration. Examples of the antioxidant include hindered phenol compounds such as 2, 6-dialkylphenol derivatives, 2-valent sulfur compounds, 3-valent phosphite compounds containing a phosphorus atom, and the like. Examples of the reducing agent include hypophosphorous acid, phosphorous acid, thiosulfuric acid, sulfurous acid, a bisulfite, and a salt thereof.

After the reaction is completed, the acid catalyst is neutralized, washed with water or decomposed to remove the acid catalyst, and the resin having the target phenolic hydroxyl group can be separated by a general operation such as extraction or distillation. The neutralization treatment and the water washing treatment may be carried out by a conventional method, and for example, an alkaline substance such as sodium hydroxide, potassium hydroxide, sodium carbonate, ammonia, triethylenetetramine, or aniline may be used as the neutralizing agent.

Specific examples of the aromatic dicarboxylic acid chloride include acid chlorides of phthalic acid, isophthalic acid, terephthalic acid, 2, 6-naphthalenedicarboxylic acid, 1, 6-naphthalenedicarboxylic acid, and 2, 7-naphthalenedicarboxylic acid. Among them, isophthaloyl dichloride and terephthaloyl dichloride are preferable in terms of balance between solvent solubility and heat resistance.

Specific examples of the monophenol-based compound include phenol, cresol, p-tert-butylphenol, 1-naphthol, and 2-naphthol. Among them, phenol, cresol and 1-naphthol are preferable from the viewpoint of good reactivity with carboxylic acid chloride, and 1-naphthol is more preferable from the viewpoint of good thermal decomposition resistance.

In the method of reacting the benzyl group-modified naphthalene compound, the aromatic dicarboxylic acid chloride, and the monophenol compound, specifically, these components may be reacted in the presence of a base catalyst.

The aforementioned reaction can be specifically carried out as follows: the above components are mixed in the presence of an organic solvent, and the reaction is carried out while continuously or intermittently dropping the above alkali catalyst or its aqueous solution. In this case, the concentration of the aqueous solution of the alkali catalyst is preferably in the range of 3.0 to 30 mass%. Examples of the organic solvent that can be used here include toluene, dichloromethane, and chloroform.

After the reaction is completed, in the case of using an aqueous solution of an alkali catalyst, the reaction solution is allowed to stand for liquid separation, the aqueous layer is removed, and the washing of the remaining organic layer is repeated until the washed aqueous layer becomes substantially neutral, whereby the target resin can be obtained.

The compound having an active ester group of (B2) thus obtained is preferred because its softening point is 100 to 200 ℃ and its solubility in organic solvents is high.

The resin layer may contain (B) a curing agent other than the compound having an active ester group, as long as the effects of the present invention are not impaired, and examples thereof include a compound having a phenolic hydroxyl group, a polycarboxylic acid and an acid anhydride thereof, a compound having a cyanate group, a compound having a maleimide group, and an alicyclic olefin polymer.

(C) inorganic Filler)

The resin layer of the laminate of the present invention contains (C) an inorganic filler. By adding the (C) inorganic filler, the curing shrinkage of the obtained cured product can be suppressed, the CTE can be reduced, and the adhesion, hardness, and thermal characteristics such as crack resistance due to thermal strength matching with a conductor layer such as copper around the insulating layer can be improved. The inorganic filler may be any conventionally known inorganic filler, and is not particularly limited to these, and examples thereof include bulk pigments such as barium sulfate, barium titanate, amorphous silica, crystalline silica, fused silica, and spherical silica, talc, clay, noninberg silica particles, boehmite, magnesium carbonate, calcium carbonate, titanium oxide, alumina, aluminum hydroxide, silicon nitride, aluminum nitride, and calcium zirconate, and metal powders such as copper, tin, zinc, nickel, silver, palladium, aluminum, iron, cobalt, gold, and platinum. The inorganic filler is preferably spherical particles. Among these, silica is preferable, and suppresses curing shrinkage of a cured product of the curable composition, resulting in a lower CTE and improved properties such as adhesion and hardness. The average particle diameter (median diameter, D50) of the inorganic filler is preferably 0.01 to 10 μm. As the inorganic filler, silica having an average particle diameter of 0.01 to 3 μm is preferable from the viewpoint of the slit processability. In the present specification, the average particle size of the inorganic filler means not only the particle size of the primary particles but also the average particle size including the particle size of the secondary particles (aggregates). The average particle diameter can be determined by a laser diffraction type particle diameter distribution measuring apparatus or a measuring apparatus based on a dynamic light scattering method. The measurement device by the laser diffraction method includes Microtrac MT3300EXII manufactured by MicrotracBEL, and the measurement device by the dynamic light scattering method includes Nanotrac Wave II UT151 manufactured by MicrotracBEL.

(C) The inorganic filler is preferably a surface-treated inorganic filler. As the surface treatment, surface treatment without introducing an organic group such as surface treatment with a coupling agent, alumina treatment, or the like can be performed. The surface treatment method of the inorganic filler is not particularly limited as long as it is a known and commonly used method, and the surface of the inorganic filler may be treated with a surface treatment agent having a curable reactive group, for example, a coupling agent having a curable reactive group as an organic group, or the like.

The surface treatment of the inorganic filler is preferably based on a surface treatment of a coupling agent. As the coupling agent, silane-based, titanate-based, aluminate-based, zircoaluminate-based, and the like coupling agents can be used. Among them, silane coupling agents are preferable. Examples of the silane coupling agent include vinyltrimethoxysilane, vinyltriethoxysilane, N- (2-aminomethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-anilinopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane and N-phenyl-3-aminopropyltrimethoxysilane, they may be used alone or in combination. These silane coupling agents are preferably adsorbed on the surface of the inorganic filler in advance or immobilized on the surface of the inorganic filler by reaction. The treatment amount of the coupling agent is, for example, 0.5 to 10 parts by mass per 100 parts by mass of the inorganic filler.

As the curable reactive group, a thermosetting reactive group is preferable. Examples of the thermosetting reactive group include a hydroxyl group, a carboxyl group, an isocyanate group, an amino group, an imino group, an epoxy group, an oxetanyl group, a mercapto group, a methoxymethyl group, a methoxyethyl group, an ethoxymethyl group, an ethoxyethyl group, and an oxazoline group. Among them, at least 1 of an amino group and an epoxy group is preferable. The surface-treated inorganic filler may have a photocurable reactive group in addition to the photocurable reactive group.

The inorganic filler subjected to surface treatment may be contained in the resin layer in a state after the surface treatment, and the inorganic filler may be mixed with the resin composition forming the resin layer separately from the inorganic filler and the surface treatment agent to perform the surface treatment on the inorganic filler in the composition. By compounding the inorganic filler after the surface treatment in advance, it is possible to prevent a reduction in crack resistance and the like due to the surface treatment agent that may remain in the surface treatment and is not consumed in the respective compounding. When the surface treatment is performed in advance, it is preferable to blend a solvent and a predispersion solution in which the inorganic filler is predispersed in the curable resin, and more preferable to blend the predispersion solution in the composition after the surface treatment by predispersing the inorganic filler in the solvent, or to blend the predispersion solution in the composition after sufficiently performing the surface treatment when the inorganic filler having not been surface-treated is predispersed in the solvent.

(C) The inorganic filler may be mixed with an epoxy resin or the like in a powder or solid state, or may be mixed with a solvent or a dispersant to form a slurry and then mixed with an epoxy resin or the like.

(C) The inorganic filler may be used alone in 1 kind, or may be used as a mixture of 2 or more kinds. The amount of the inorganic filler (C) is preferably 30% by mass or more, more preferably 50% by mass or more, further preferably 60% by mass or more, and particularly preferably 65% by mass or more, from the viewpoint of lowering the CTE, when the nonvolatile content in the resin layer is 100% by mass. From the viewpoint of toughness of the cured film, it is preferably 90% by mass or less, and more preferably 85% by mass or less.

(curing accelerators)

The resin layer may contain a curing accelerator. The curing accelerator is used for accelerating a thermosetting reaction and further improving properties such as adhesion, chemical resistance, and heat resistance. Specific examples of such a curing accelerator include: imidazole and derivatives thereof; guanamines such as methylguanamine and benzoguanamine; polyamines such as diaminodiphenylmethane, m-phenylenediamine, m-xylylenediamine, diaminodiphenylsulfone, dicyandiamide, urea derivatives, melamine, and polyhydrazide; organic acid salts and/or epoxy adducts thereof; an amine complex of boron trifluoride; triazine derivatives such as ethyldiamino-s-triazine, 2, 4-diamino-s-triazine, and 2, 4-diamino-6-xylyl-s-triazine; amines such as trimethylamine, triethanolamine, N-dimethyloctylamine, N-benzyldimethylamine, pyridine, dimethylaminopyridine, N-methylmorpholine, hexa (N-methyl) melamine, 2,4, 6-tris (dimethylaminophenol), tetramethylguanidine, and m-aminophenol; polyphenols such as polyvinyl phenol, polyvinyl phenol bromide, phenol novolac, and alkylphenol novolac; organic phosphines such as tributylphosphine, triphenylphosphine, and tris-2-cyanoethylphosphine; phosphonium salts such as tri-n-butyl (2, 5-dihydroxyphenyl) phosphonium bromide and hexadecyltributylphosphonium chloride; quaternary ammonium salts such as benzyltrimethylammonium chloride and phenyltributylammonium chloride; the foregoing polybasic acid anhydrides; photocationic polymerization catalysts such as diphenyliodonium tetrafluoroborate, triphenylsulfonium hexafluoroantimonate, 2,4, 6-triphenylmercaptopyridinium hexafluorophosphate and the like; styrene-maleic anhydride resin; an equimolar reaction product of phenyl isocyanate and dimethylamine, an equimolar reaction product of an organic polyisocyanate such as toluene diisocyanate or isophorone diisocyanate and dimethylamine, a conventionally known curing accelerator such as a metal catalyst. Among the curing accelerators, imidazole and derivatives thereof and dimethylaminopyridine are preferable, and imidazole and derivatives thereof are more preferable in that a cured product having a higher Tg and a low dielectric loss tangent can be obtained.

The curing accelerator may be used alone in 1 kind or in combination of 2 or more kinds. The amount of the curing accelerator to be added is preferably 5% by mass or less, more preferably 3% by mass or less, from the viewpoint of storage stability of the resin layer before the thermosetting reaction, and preferably 0.01% by mass or more, more preferably 0.1% by mass or more, from the viewpoint of curability, when the total amount of the (a) epoxy resin and the (B) compound having an active ester group in the resin layer is 100% by mass.

(thermoplastic resin (Polymer resin))

The aforementioned resin layer may further contain a thermoplastic resin to improve the mechanical strength of the resulting cured film. The thermoplastic resin is preferably soluble in a solvent. When the resin is soluble in a solvent, the flexibility of the resin layer is improved, and the occurrence of cracks and powder falling can be suppressed. Examples of the thermoplastic resin include: thermoplastic polyhydroxypolyether resins, phenoxy resins which are condensates of epichlorohydrin and various 2-functional phenol compounds, phenoxy resins obtained by esterifying the hydroxyl group of a hydroxyether moiety present in the skeleton thereof with various acid anhydrides or acid chlorides, polyvinyl acetal resins, polyamide resins, polyamideimide resins, block copolymers, and the like. The thermoplastic resin can be used alone in 1, or a combination of 2 or more. Among these thermoplastic resins, phenoxy resins are preferred because they can improve the glass transition temperature while keeping the dielectric loss tangent low. From the viewpoint of reducing the surface roughness of the cured product after desmear, a polyvinyl acetal resin is preferred.

The polyvinyl acetal resin can be obtained, for example, by acetalizing a polyvinyl alcohol resin with an aldehyde. The aldehyde is not particularly limited, and examples thereof include formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, valeraldehyde, caproaldehyde, heptaldehyde, 2-ethylcaproaldehyde, cyclohexanal, furfural, benzaldehyde, 2-methylbenzaldehyde, 3-methylbenzaldehyde, 4-methylbenzaldehyde, p-hydroxybenzaldehyde, m-hydroxybenzaldehyde, phenylacetaldehyde, and β -phenylpropionaldehyde, and butyraldehyde is preferable.

Specific examples of the phenoxy resin include FX280 and FX293 manufactured by Nippon iron Chemical & materials Co., Ltd, YX8100, YX6954, YL6974 and YX7200 manufactured by Mitsubishi Chemical Corporation, and the like. Specific examples of the polyvinyl acetal resin include an ESLEC KS series manufactured by wakeh chemical industries, a KS5000 series manufactured by hitachi chemicals, a BP series manufactured by japan chemicals, and a KS9000 series manufactured by hitachi chemicals. The amount of the thermoplastic resin is preferably 0.1 mass% or more, more preferably 0.3 mass% or more, from the viewpoint of the mechanical strength of the cured film obtained when the total amount of the epoxy resin (a) and the compound having an active ester group (B) in the resin layer is 100 mass%. In addition, from the viewpoint of dielectric characteristics of the cured film, 30 mass% or less is preferable, and 20 mass% or less is more preferable.

(rubber-like particles)

The resin layer may contain rubber-like particles as necessary. Examples of such rubber-like particles include polybutadiene rubber, polyisopropylene rubber, urethane-modified polybutadiene rubber, epoxy-modified polybutadiene rubber, acrylonitrile-modified polybutadiene rubber, carboxyl-modified polybutadiene rubber, acrylonitrile-butadiene rubber modified with a carboxyl group or a hydroxyl group, and crosslinked rubber particles and core-shell rubber particles thereof, and 1 type of such rubber-like particles can be used alone or 2 or more types can be used in combination. These rubber-like particles are added for the purpose of improving the flexibility of the obtained cured film, improving the crack resistance, performing surface roughening treatment with an oxidizing agent, and improving the adhesion strength to a copper foil or the like.

The average particle diameter of the rubber-like particles is preferably in the range of 0.005 to 15 μm, more preferably in the range of 0.2 to 10 μm. The average particle diameter of the rubber-like particles in the present invention can be measured by the same method as the average particle diameter of the inorganic filler.

(flame retardant)

The resin layer may contain a flame retardant. Examples of the flame retardant include hydrated metal-based flame retardants such as aluminum hydroxide and magnesium hydroxide, red phosphorus, ammonium phosphate, ammonium carbonate, zinc borate, zinc stannate, molybdenum compounds, bromine compounds, chlorine compounds, phosphate esters, phosphorus-containing polyols, phosphorus-containing amines, melamine cyanurate, melamine compounds, triazine compounds, guanidine compounds, and silicon polymers. The flame retardant may be used alone in 1 kind, or in combination of 2 or more kinds.

(organic solvent)

The organic solvent is not particularly limited, and examples thereof include ketones, aromatic hydrocarbons, glycol ethers, glycol ether acetates, esters, alcohols, aliphatic hydrocarbons, petroleum solvents, and the like. More specifically, there may be mentioned: ketones such as methyl ethyl ketone, cyclohexanone, methyl butyl ketone, and methyl isobutyl ketone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; glycol ethers such as cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, dipropylene glycol diethyl ether, and triethylene glycol monoethyl ether; esters such as ethyl acetate, butyl acetate, isobutyl acetate, ethylene glycol monoethyl ether acetate, dipropylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, and propylene glycol butyl ether acetate; alcohols such as ethanol, propanol, 2-methoxypropanol, n-butanol, isobutanol, isoamyl alcohol, ethylene glycol and propylene glycol; aliphatic hydrocarbons such as octane and decane; petroleum solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvent naphtha; and N, N-Dimethylformamide (DMF), tetrachloroethylene, turpentine, and the like. Further, organic solvents such as Swasol 1000 manufactured by Wanshan petrochemical Co., Ltd., Swasol 1500, SOLVESSO 100 manufactured by Saka Proc., Ltd., SOLVESSO 150, Solvent #100 manufactured by Sanko chemical Co., Ltd., Solvent #150, ShellSol A100 manufactured by Nippon Shell chemical Co., Ltd., ShellSol A150, Ipsol No. 100 manufactured by Shikoku Co., Ltd., Ipsol No. 150 and Ipsol No. 150 may be used. The organic solvent may be used alone in 1 kind, or in combination of 2 or more kinds.

The amount of the residual solvent in the resin layer is preferably 0.5 to 10.0 mass%. When the residual solvent content is 10.0% by mass or less, bumping during thermal curing is suppressed, and the surface flatness is improved. Further, excessive decrease in melt viscosity can be suppressed, and the resin can flow and be made excellent in flatness. When the residual solvent content is 0.5% by mass or more, the fluidity at the time of lamination is good, and the flatness and embeddability become better.

(other Components)

The aforementioned resin layer may further be used as necessary: organic fillers such as silica powder, fluorine powder and nylon powder, conventionally known colorants such as phthalocyanine blue, phthalocyanine green, iodine green, bisazo yellow, crystal violet, titanium oxide, carbon black and naphthalene black, conventionally known thickeners such as asbestos, silica, bentonite, fine powder silica, conventionally known antifoaming agents and/or leveling agents such as silicone-based, fluorine-based and polymer-based ones, adhesion imparting agents such as thiazole-based, triazole-based and silane coupling agents, conventionally known additives such as titanate-based and aluminum-based ones.

[ extra thin copper foil ]

In the present invention, the extra thin copper foil has a thickness of 0.1 to 6 μm. The method for forming the extra thin copper foil is not particularly limited, and the extra thin copper foil can be formed by a known method by a wet film forming method such as an electroless copper plating method or an electrolytic copper plating method, a dry film forming method such as sputtering or chemical vapor deposition, or a combination thereof. From the viewpoint of easy control of the thickness of the extra thin copper foil, the electroplating method is preferred. For example, an auxiliary metal layer such as a nickel layer is formed on a carrier foil, and then the carrier foil is immersed in a copper solution having a copper concentration of 20 to 100g/L and a sulfuric acid concentration of 100 to 300g/L at a current density of 5 to 30A/dm²Then, the electrolysis is performed to form an extra thin copper foil.

The surface of the extra thin copper foil is preferably roughened. The roughening treatment is not particularly limited, and may be formed by a known and commonly used method. For example, the roughening treatment can be performed by performing a firing step of depositing and adhering fine copper particles to the extra thin copper foil and a coating step of preventing the fine copper particles from falling off after deposition and adhesion. For example, in the process of the baking and plating,an acidic copper sulfate solution containing copper at a concentration of 10g/L and sulfuric acid at a concentration of 120g/L at a liquid temperature of 25 ℃ and a current density of 15A/dm may be used²Then, a roughening treatment was performed, and in the subsequent coating step, an acidic copper sulfate solution containing 70g/L copper and 120g/L sulfuric acid was used at a liquid temperature of 40 ℃ and a current density of 15A/dm²The smooth plating condition of (2) is to perform electrodeposition.

From the viewpoint of fine circuit formability, the ten-point average roughness Rz of the surface of the extra thin copper foil on the resin layer side is preferably 4.0 μm or less. More preferably 3.0 μm or less, and still more preferably 2.5 μm or less. From the viewpoint of adhesion to the resin layer, the thickness is preferably 0.5 μm or more, more preferably 1.0 μm or more. Here, the ten-point average roughness Rz is a value in accordance with JIS B0601: 2001, the roughness curve of the reference length is the sum of the average of the peak heights from the highest peak to the 5 th peak in the height order and the average of the valley depths from the deepest valley to the 5 th peak in the depth order. The ten-point average roughness Rz can be determined as follows: the measurement was performed under a condition of 11 μm with a low-frequency filter using a commercially available three-dimensional surface structure analysis microscope (for example, Zygo New View 5032 (manufactured by Zygo corporation)) and commercially available analysis software (for example, Metro Pro ver.8.0.2). At this time, the non-measurement surface of the foil was fixed in close contact with the sample table, 6 points of the field of view of 108 μm × 144 μm in the range of 1cm square of the sample sheet were selected and measured, and the average value of the measurement values obtained from the measurement points of 6 sites was used as a representative value.

[ Carrier foil ]

The method for forming the carrier foil is not particularly limited, and examples thereof include a copper foil, an aluminum foil, a stainless steel (SUS) foil, a resin film with a metal-coated surface, and the like, and a copper foil is preferable. The copper foil may be an electrolytic copper foil or a rolled copper foil. The thickness of the carrier foil is usually 250 μm or less, preferably 9 to 200 μm.

As the extra thin copper foil and the carrier foil, commercially available ones can be used, and as the extra thin copper foil with carrier foil, for example, MT18Ex, MT18FL, MT18SD-H manufactured by Mitsui Metal mining Co., Ltd., and the like can be used.

[ laminate ]

The laminate of the present invention may have a carrier foil, an extra thin copper foil having a thickness of 0.1 to 6 μm, and a resin layer in this order, and may have other layers as necessary. For example, a release layer or an auxiliary metal layer may be provided between the carrier foil and the extra thin copper foil, or a protective film may be provided on the resin layer.

The release layer may be either an organic release layer or an inorganic release layer. Examples of the organic component of the organic release layer include nitrogen-containing organic compounds such as triazole compounds, sulfur-containing organic compounds, and carboxylic acids. Examples of the inorganic component of the inorganic release layer include Ni, Mo, Co, Cr, Fe, Ti, W, P, Zn, chromate-treated film, and the like.

As the auxiliary metal layer, a layer containing nickel and/or cobalt is preferred, by which the stability of the tear strength of the carrier foil becomes good.

The protective film is provided on the resin layer for the purpose of preventing dust and the like from adhering to the surface of the resin layer and improving workability. Examples of the protective film include polyester films such as polyethylene terephthalate and polyethylene naphthalate, polyimide films, polyamideimide films, polyethylene films, polytetrafluoroethylene films, polypropylene films, polystyrene films and other thermoplastic resins, and surface-treated papers, among which polyester films, polyethylene films and polypropylene films are preferred. The thickness of the protective film is not particularly limited, and may be appropriately selected within a range of approximately 5 to 150 μm depending on the application. The surface of the protective film on which the resin layer is provided may be subjected to a mold release treatment.

The method for producing the laminate of the present invention is not particularly limited, and for example, the laminate can be produced by applying a resin composition containing (a) an epoxy resin, (B) a compound having an active ester group, and (C) an inorganic filler onto a commercially available extra thin copper foil with a carrier foil, and drying the resin composition to form a resin layer as a dried coating film.

The laminate of the present invention is preferably a resin-coated copper foil (RCC) used for the production of a multilayer circuit board. As a method for manufacturing an electronic component using the laminate of the present invention, a conventionally known method can be used. The method for curing the resin layer of the laminate of the present invention is not particularly limited, and the resin layer may be cured by a conventionally known method, for example, by heating at 150 to 230 ℃. The method for producing a printed wiring board using the laminate of the present invention includes, for example, the following methods. The laminate of the present invention is laminated by heat lamination and heat cured in such a manner that the resin layer side is in contact with the circuit substrate on which the circuit pattern is formed. The heat curing may be carried out in an oven or under hot plate pressure. Then, the extra thin copper foil can be used as all or a part of the wiring layer to form a circuit by a modified semi-additive process (MSAP) method, thereby manufacturing a laminated circuit board. Alternatively, the extra thin copper foil may be removed, and a circuit-formed laminated circuit board may be manufactured by a semi-additive process (SAP) method. In addition, a printed circuit board may be manufactured by direct build-up on wafer (direct build-up on wafer) in which lamination of a copper foil with resin and circuit formation are alternately repeated on a semiconductor integrated circuit. In addition, a coreless lamination method in which resin layers and conductor layers are alternately laminated may be used without using a core substrate. The carrier foil may be peeled at any stage after lamination, after heat curing, after laser processing, or after desmear treatment.

The laminate of the present invention can be preferably used for forming a permanent protective film for electronic parts, particularly multilayer printed wiring boards, and among them, can be preferably used for forming an interlayer insulating layer. The cured product of the resin layer of the laminate of the present invention has excellent dielectric properties, and therefore, can be suitably used for high-frequency applications in which transmission loss is a problem. Specific examples of the high-frequency application include: a microwave radar for autonomous driving, a Substrate for a microwave sensor, a main board for movement coping with high-speed communication, SLP (Substrate-Like PCB) for forming a circuit by an improved semi-additive process (MSAP) method, an Application Processor (AP) for mobile and personal computers, a smart phone, a tablet, an HDI (high density interconnect) Substrate for personal computers, a PKG (package) Substrate, a high multi-layer Substrate for a base station server, a router, a Substrate for an antenna, and the Like. The laminate of the present invention can be used to form a circuit board by bonding wires. The electronic component may be a passive component such as an inductor, for example, for an application other than a printed circuit board. In addition, according to the laminate of the present invention, even when the total amount of the active ester groups is large, that is, when the ratio of the total amount of the epoxy groups of the epoxy resin (a) to the total amount of the active ester groups of the compound having an active ester group (B) in the resin layer is 0.20 to 0.60, a fine pattern can be formed with good adhesion on the insulating layer, and therefore, the laminate is suitable for use in forming a circuit having a line width/line pitch of 35 μm or less/35 μm or less, for example.

The dielectric loss tangent of the cured product of the present invention is not particularly limited, and according to the present invention, a cured product having a low dielectric loss tangent can be obtained, and for example, the dielectric loss tangent can be set to 0.005 or less, further 0.003 or less, and further 0.002 or less.

Examples

The present invention will be specifically described below by way of examples and comparative examples thereof, but the present invention is not limited to the following examples. In the following, all of the terms "part" and "%" are based on mass unless otherwise specified.

< Synthesis of Compound having active ester group >

Synthesis example 1 Synthesis of a Compound having an active ester group (B-1)

203.0g of isophthaloyl dichloride (the number of moles of acid chloride groups: 2.0 moles) and 1338g of toluene were put into a flask equipped with a thermometer, a dropping funnel, a condenser, a fractionating tube and a stirrer, and the inside of the system was reduced in pressure and dissolved by replacing with nitrogen. Then, 96.0g (0.67 mol) of α -naphthol and 220g (the number of moles of phenolic hydroxyl groups: 1.33 mol) of dicyclopentadiene phenol resin were charged, and the system was depressurized and dissolved by replacing with nitrogen. Thereafter, 1.12g of tetrabutylammonium bromide was dissolved, and 400g of a 20% aqueous sodium hydroxide solution was added dropwise over 3 hours while controlling the temperature in the system to 60 ℃ or lower by purging with nitrogen gas.

Subsequently, stirring was continued under these conditions for 1.0 hour. After the reaction, the mixture was allowed to stand for liquid separation, and the aqueous layer was removed. Further, water was put into the toluene phase in which the reaction product was dissolved, and the mixture was stirred for about 15 minutes, and the mixture was allowed to stand for liquid separation to remove the water layer. This operation was repeated until the pH of the aqueous layer became 7. Then, the reaction mixture was dewatered by decantation to remove water, thereby obtaining an active ester resin (B-1) in the form of a toluene solution having a nonvolatile content of 65%. The active ester resin (B-1) thus obtained had an ester group equivalent of 223g/eq.

(Synthesis example 2 Synthesis of Compound having an active ester group (B-2))

In a flask equipped with a thermometer, a dropping funnel, a condenser, a fractionating tube and a stirrer, 320g (2.0 mol) of 2, 7-dihydroxynaphthalene, 184g (1.7 mol) of benzyl alcohol and 5.0g of p-toluenesulfonic acid monohydrate were charged, and the mixture was stirred at room temperature while blowing nitrogen gas. Thereafter, the temperature was raised to 150 ℃ and the resultant water was distilled off to the outside of the system and stirred for 4 hours. After completion of the reaction, 900g of methyl isobutyl ketone and 5.4g of a 20% aqueous solution of sodium hydroxide were added to neutralize the reaction mixture, and then the aqueous layer was removed by liquid separation, followed by washing with 280g of water for 3 times to remove the methyl isobutyl ketone under reduced pressure, thereby obtaining 460g of a benzyl-modified naphthalene compound (intermediate B-2). The obtained benzyl-modified naphthalene compound (B-2 intermediate) was a black solid having a hydroxyl equivalent of 180g/eq.

203.0g of isophthaloyl dichloride (the number of moles of acid chloride groups: 2.0 moles) and 1400g of toluene were put into a flask equipped with a thermometer, a dropping funnel, a condenser, a fractionating tube and a stirrer, and the system was dissolved by replacing the atmosphere with nitrogen under reduced pressure. Then, 96.0g (0.67 mol) of α -naphthol and 240g (the number of moles of phenolic hydroxyl groups: 1.33 mol) of benzyl-modified naphthalene compound (intermediate of B-2) were charged, and the inside of the system was reduced in pressure and dissolved by replacing with nitrogen. Thereafter, 0.70g of tetrabutylammonium bromide was dissolved, and 400g of a 20% aqueous sodium hydroxide solution was added dropwise over 3 hours while controlling the temperature in the system to 60 ℃ or lower by purging with nitrogen gas. Subsequently, stirring was continued under these conditions for 1.0 hour. After the reaction, the mixture was allowed to stand for liquid separation, and the aqueous layer was removed. Further, water was added to the toluene layer in which the reaction product was dissolved, and the mixture was stirred for 15 minutes, and then the mixture was allowed to stand for liquid separation to remove the water layer. This operation was repeated until the pH of the aqueous layer became 7. Then, the reaction mixture was dewatered by decantation to remove water, thereby obtaining an active ester resin (B-2) in the form of a toluene solution having a nonvolatile content of 65 mass%. The active ester resin (B-2) thus obtained had an ester group equivalent of 230g/eq.

< preparation of curable resin composition >

The curable resin compositions were prepared by kneading and mixing the components shown in examples and comparative examples of tables 1 and 2 below in the proportions (parts by mass) shown in tables 1 and 2. The numerical values in the table represent parts by mass (in terms of nonvolatile components).

< determination of dielectric loss tangent (DF) >

Each of the curable resin compositions was applied to a glossy surface of a copper foil (18 μm thick F2-WS, manufactured by Kogawa electric industries, Ltd.) using a film applicator in accordance with examples and comparative examples, dried at 90 ℃ for 10 minutes in a hot air circulation type drying furnace, then cured at 200 ℃ for 60 minutes, and then the copper foil was peeled off to prepare a cured film (cured film) having a thickness of about 40 μm. The obtained cured film was cut into a measurement size (50 mm. times.60 mm size), and the dielectric loss tangent at 23 ℃ of 10GHz was measured using an SPDR dielectric resonator and a network analyzer (both Agilent Co., Ltd.), and evaluated according to the following criteria.

Very good: less than 0.003

Good: 0.003 or more and less than 0.010

X: 0.010 or more

< production of RCC (copper foil with resin) with Carrier foil >

The curable resin compositions of examples 1 to 14 and comparative example 1 were applied to the laminated surface (roughness Rz of copper foil is 2 μm) of each carrier-attached extra thin copper foil (MT 18Ex manufactured by mitsui metal mining co., ltd., 3 μm thick) using a film applicator, and dried at 90 ℃ for 10 minutes in a hot air circulation drying oven to prepare an RCC (resin-attached copper foil) with a carrier foil having a resin layer thickness of about 40 μm.

< preparation of RCC (copper foil with resin) >

The curable resin compositions of comparative examples 2 and 3 were applied to the laminated surfaces (roughness Rz of copper foil 2 μ M) of electrolytic copper foils (3 EC-M2S-VLP, manufactured by mitsui metal mining co., ltd., 18 μ M thick) using a film applicator, and dried at 90 ℃ for 10 minutes in a hot air circulation drying oven to prepare RCC (copper foil with resin) having a resin layer thickness of about 40 μ M.

< evaluation of laser hole-opening workability >

(i) The RCC with Carrier foil of examples 1 to 14 and comparative example 1 prepared as described above

The surface of the RCC on the resin layer side was laminated on the surface of the substrate, and after thermocompression bonding at 4.0MPa and 200 ℃ for 90 minutes, the carrier foil was peeled off to produce a copper-clad laminate for evaluation.

(ii) RCC of comparative examples 2 and 3 prepared as described above

The resin layer side of the RCC was laminated on the surface of the substrate, thermocompression bonded at 4.0MPa and 200 ℃ for 90 minutes, and then the copper foil of the laminated plate was subjected to full-surface etching with a copper chloride etching solution so that the thickness of the copper foil became about 3 μm, to produce a copper-clad laminated plate for evaluation.

Then, the copper-clad laminate produced in (i) and (ii) was subjected to laser drilling using a carbon dioxide laser under conditions of a pulse width of 12 μ sec., a pulse energy of 8mJ, and a laser beam diameter of 97 μm. The diameters in the x direction and the y direction of 10 holes formed by laser drilling were measured, and the average value was calculated as the hole diameter after the drilling. When the difference between the maximum value and the minimum value of the pore diameter (10 points) after the machining was less than 3 μm, the product was judged as "excellent" and 3 μm or more was judged as "x".

< evaluation of reflow resistance >

First, the copper-clad laminate was cut into a length and width of 10cm × 10cm, and the treatment was repeated 10 times in a reflow furnace (285 ℃ C. at the maximum). After the treatment, the case of no appearance defect such as swelling was judged as "excellent" and the case of appearance defect such as swelling was judged as "x" by visual confirmation.

[ Table 1]

[ Table 2]

1, 1: EXA-835LV (bisphenol A epoxy resin and bisphenol F epoxy resin mixture, liquid epoxy equivalent: 165g/eq.) manufactured by DIC corporation

A, 2: NC-3000H (Biphenylalkyl epoxy resin, solid, epoxy equivalent: 290g/eq.) manufactured by Nippon Chemicals corporation

3, a: active ester resin B-1 (active ester equivalent: 223g/eq.) synthesized in Synthesis example 1 above

4, v: active ester resin B-2 (active ester equivalent: 230g/eq.) synthesized in Synthesis example 2 above

5, a step of: TD-2090 manufactured by DIC corporation (phenol novolac, hydroxyl equivalent: 105g/eq.)

V6: SO-C2 (spherical silica, average particle size: 0.5 μm) manufactured by Admatechs corporation treated with phenylaminosilane

7, a: JeR YX7200B35 (phenoxy resin) manufactured by Mitsubishi Chemical Corporation

8, V: 2E4MZ (2-Ethyl-4-methylimidazole) manufactured by Siguohuai Kaisha

9, a: thickness of the copper foil before etching. After etching, about 3 μm.

From the results shown in the table, it is understood that the laminate of the present invention is excellent in laser hole drilling processability and reflow resistance, and the cured product of the resin layer has a low dielectric loss tangent.

Description of the reference numerals

1 laminated body

2 carrier foil

3 very thin copper foil

4 resin layer

Claims

1. A laminate comprising, in order, at least: a carrier foil, an extra thin copper foil having a thickness of 0.1 to 6 μm, and a resin layer,

the resin layer includes: (A) an epoxy resin, (B) a compound having an active ester group, and (C) an inorganic filler.

2. The laminate according to claim 1, wherein the ratio of the total amount of epoxy groups of the epoxy resin (A) to the total amount of active ester groups of the compound having active ester groups (B) in the resin layer is 0.20 to 0.60.

3. The laminate according to claim 1 or 2, wherein the amount of the inorganic filler (C) is 50% by mass or more, assuming that 100% by mass of nonvolatile components in the resin layer are present.

4. The laminate according to any one of claims 1 to 3, wherein the compound (B) having an active ester group is a compound represented by the following general formula (1),

in the formula, X₁Each independently a group having a benzene ring or a naphthalene ring, k represents 0 or 1, and n is 0.25 to 1.5 on the average of the repeating units.

5. The laminate according to any one of claims 1 to 3, wherein the compound (B) having an active ester group is a compound having a structure having a structural site represented by the following general formula (2) and having a structure in which both terminals thereof are monovalent aryloxy groups,

in the formula (2), X₂Each independently is a group represented by the following formula (3) or a group represented by the following formula (4),

in the formula (3), k is an integer of 1 to 5,

in the formula (4), Y is a group shown in the formula (3), k is an integer of 1-5 independently, and t is an integer of 0-5 independently.

6. The laminate according to any one of claims 1 to 5, wherein the ratio of the total amount of epoxy groups of the epoxy resin (A) to the total amount of active ester groups of the compound having active ester groups (B) in the resin layer is 0.20 to 0.50.

7. The laminate according to any one of claims 1 to 6, wherein a dielectric loss tangent of a cured product of the resin layer is 0.01 or less.

8. An electronic component comprising a cured product obtained by curing the resin layer of the laminate according to any one of claims 1 to 7.