Prepreg, laminate, metal-clad laminate, printed wiring board, and semiconductor package

Abstract

Provided is a prepreg that can exhibit excellent drillability and have a low dielectric constant (Dk). Also provided are a laminate, a metal-clad laminate, a printed wiring board, and a semiconductor package, which are manufactured using the prepreg. Specifically, the prepreg contains a fibrous base material and has a linear thermal expansion coefficient of 4.6-5.4 ppm / °C as measured according to the measurement method described in the specification, and a dielectric loss tangent (Df) of 0.0050-0.0070 as measured according to the measurement method described in the specification.

Description

Prepregs, laminates, metal-clad laminates, printed circuit boards, and semiconductor packages

[0001] This disclosure relates to prepregs, laminates, metal-clad laminates, printed circuit boards, and semiconductor packages.

[0002] In recent years, there has been a growing demand for miniaturization, weight reduction, higher wiring density, and faster processing speeds for printed circuit boards (PCBs) used in electronic devices, communication equipment, and the like. Consequently, higher reliability is increasingly required for the insulating layer of PCBs. Currently, prepregs, obtained by impregnating a resin composition into a fibrous substrate such as glass cloth, are used as insulating materials for PCBs. In the PCB manufacturing process, drilling holes is sometimes performed on the cured prepreg to form vias, etc. However, to lower the thermal expansion coefficient of the insulating layer, inorganic fillers are sometimes used at high concentrations, or harder fibrous substrates are employed. In such cases, the deterioration of drillability tends to become more pronounced. Under these circumstances, a resin composition containing a molybdenum compound supported on inorganic particles has been proposed as a method to improve the drillability of resin compositions (see, for example, Patent Document 1).

[0003] Japanese Patent Publication No. 2019-199562

[0004] However, the method described in Patent Document 1 requires a molybdenum compound as an inorganic filler, which presents a problem as it cannot be used when other inorganic fillers are desired. Therefore, the development of other means to improve drillability is urgently needed. Furthermore, in recent years, there has been a demand for insulating materials with excellent dielectric properties in the high-frequency band (e.g., 10 GHz or higher) that enable the reduction of transmission loss. Therefore, in addition to improving drillability, there is also a need to reduce the relative permittivity (Dk).

[0005] In view of the above circumstances, this disclosure aims to provide a prepreg that can exhibit excellent drillability and have a low dielectric constant (Dk). Furthermore, it also aims to provide laminates, metal-clad laminates, printed circuit boards, and semiconductor packages manufactured using the prepreg.

[0006] The present inventors have conducted studies to achieve the above objective and have found that the present disclosure can achieve the above objective. The present disclosure includes the following embodiments [1] to

[13] .

[0007] [1] A prepreg containing a fibrous substrate, wherein the linear thermal expansion coefficient measured according to the following measurement method is 4.6 to 5.4 ppm / °C, and the dielectric loss tangent (Df) measured according to the following measurement method is 0.0050 to 0.0070. (Method for measuring linear thermal expansion coefficient) A thermosetting resin composition is prepared containing 80 parts by mass of a siloxane-modified maleimide compound, 20 parts by mass of a biphenyl aralkyl novolac-type epoxy resin, 150 parts by mass of molten spherical silica, and 0.5 parts by mass of isocyanate maximidazole. The thermosetting resin composition is impregnated into a fibrous substrate and then heated at 120°C for 5 minutes and dried to produce a prepreg. Ten layers of the prepreg are stacked to form a laminate, and 12 μm thick copper foil is placed on the top and bottom of the laminate so that the M-side (matte side) is in contact with the prepreg. Then, a double-sided copper-clad laminate is produced by heating and pressurizing it at a temperature of 240°C, a pressure of 3.0 MPa, and a time of 90 minutes. The copper foil is removed from the resulting double-sided copper-clad laminate by immersion in a copper etching solution. The resulting resin plate is cut to a width of 5 mm and a length of 5 mm to be used as the evaluation substrate. Thermomechanical analysis is performed using the tensile method with a thermomechanical analyzer (TMA). After mounting the evaluation substrate in the X direction on the apparatus, one measurement is taken under measurement conditions of a load of 5 g and a heating rate of 10°C / min. The average thermal expansion coefficient (average of the linear thermal expansion coefficient in the plane direction) from 30°C to 100°C is calculated. The obtained value is taken as the value of the linear thermal expansion coefficient. (Method for measuring dielectric loss tangent (Df)) A thermosetting resin composition is prepared containing 80 parts by mass of a siloxane-modified maleimide compound, 20 parts by mass of a biphenyl aralkyl novolac-type epoxy resin, 150 parts by mass of molten spherical silica, and 0.5 parts by mass of isocyanate maximidazole. A prepreg is prepared by impregnating a fiber substrate with the thermosetting resin composition and then heating and drying it at 120°C for 5 minutes. Ten layers of the prepreg are stacked to form a laminate, and 12 μm thick copper foil is placed on the top and bottom of the laminate so that the M side (matte side) is in contact with the prepreg. A double-sided copper-clad laminate is then prepared by heating and pressing it at a temperature of 240°C, a pressure of 3.0 MPa, and a time of 90 minutes. The copper foil is removed from the double-sided copper-clad laminate by immersion in a copper etching solution. The obtained resin plate is cut to a width of 2 mm and a length of 50 mm to be used as an evaluation substrate.Next, the dielectric loss tangent (Df) of the test specimen is measured in accordance with the cavity resonator perturbation method at an ambient temperature of 25°C and in the 10 GHz band. [2] The prepreg according to [1] above, wherein the fibrous substrate is glass cloth. [3] SiO in the glass cloth. ２ [1] or [2] above, wherein the content of is 61% by mass or less relative to the total amount of glass cloth. [4] A prepreg according to any one of [1] to [3] above, further comprising a semi-cured product of a thermosetting resin composition containing (A) a thermosetting resin. [5] A prepreg according to [4] above, wherein the (A) component comprises at least one selected from the group consisting of epoxy resin, polyimide resin, maleimide compound, phenol resin, polyphenylene ether resin, bismaleimide triazine resin, cyanate resin, isocyanate resin, benzoxazine resin, oxetane resin, amino resin, unsaturated polyester resin, allyl resin, dicyclopentadiene resin, and silicone resin. [6] A prepreg according to [4] or [5] above, wherein the (A) component comprises at least one selected from the group consisting of maleimide compounds having one or more N-substituted maleimide groups and derivatives thereof. [7] The prepreg according to any one of [4] to [6] above, wherein the component (A) comprises a siloxane-modified maleimide compound. [8] The prepreg according to any one of [1] to [7] above, wherein the thermosetting resin composition further contains (B) a filler. [9] The prepreg according to any one of [1] to [8] above, wherein the thermosetting resin composition further contains (C) a curing accelerator.

[10] A laminate containing a cured product of the prepreg according to any one of [1] to [9] above.

[11] A metal-clad laminate containing metal foil and a cured product of the prepreg according to any one of [1] to [9] above.

[12] A printed circuit board containing the laminate according to

[10] above or the metal-clad laminate according to

[11] above.

[13] A semiconductor package containing the printed circuit board according to

[12] above and a semiconductor element.

[0008] According to this disclosure, it is possible to provide a prepreg that can exhibit excellent drillability and have a low dielectric constant (Dk). Furthermore, it is possible to provide laminates, metal-clad laminates, printed circuit boards, and semiconductor packages manufactured using the prepreg.

[0009] In the numerical ranges described herein, the upper or lower limits of the range may be replaced with the values ​​shown in the examples. Furthermore, the lower and upper limits of a numerical range may be arbitrarily combined with the lower or upper limits of other numerical ranges. In the notation "AA to BB" for a numerical range, the numbers AA and BB at both ends are included in the range as the lower and upper limits, respectively. In this specification, for example, "10 or more" means 10 and numbers greater than 10, and this applies even if the numbers are different. Similarly, for example, "10 or less" means 10 and numbers less than 10, and this applies even if the numbers are different. Also, unless otherwise specified, each component and material exemplified herein may be used alone or in combination of two or more. In this specification, the content of each component in a composition means the total amount of multiple substances present in the composition, unless otherwise specified, when multiple substances corresponding to each component exist in the composition.

[0010] In this specification, "solids" refers to components other than the organic solvents described later, and components that are liquid at 25°C are also considered solids. The expression "contains XX" as described in this specification means that XX may be contained in a reacted state if XX is reactable, or it may simply mean that XX is contained. Embodiments that combine any combination of the matters described in this specification are also included.

[0011] [Prepreg] One embodiment of this prepreg is a prepreg containing a fibrous base material, wherein the linear thermal expansion coefficient measured according to the measurement method below is 4.6 to 5.4 ppm / °C, and the dielectric loss tangent (Df) measured according to the measurement method below is 0.0050 to 0.0070.

[0012] (Method for measuring linear thermal expansion coefficient) A thermosetting resin composition is prepared containing 80 parts by mass of a siloxane-modified maleimide compound, 20 parts by mass of a biphenyl aralkyl novolac-type epoxy resin, 150 parts by mass of molten spherical silica, and 0.5 parts by mass of isocyanate maximidazole. A prepreg is prepared by impregnating a fiber substrate with the thermosetting resin composition and then heating and drying it at 120°C for 5 minutes. Ten layers of the prepreg are stacked to form a laminate, and 12 μm thick copper foil is placed on the top and bottom of the laminate so that the M-side (matte side) is in contact with the prepreg. A double-sided copper-clad laminate is then prepared by heating and pressing it at a temperature of 240°C, a pressure of 3.0 MPa, and a time of 90 minutes. The copper foil is removed from the double-sided copper-clad laminate by immersion in a copper etching solution. The obtained resin plate is cut to a width of 5 mm x length of 5 mm to be used as an evaluation substrate. Thermomechanical analysis is performed using the tensile method with a thermomechanical analyzer (TMA). After mounting the evaluation substrate in the X direction on the apparatus, one measurement is performed under measurement conditions of a load of 5g and a heating rate of 10°C / min. The average thermal expansion coefficient (average of the linear thermal expansion coefficient in the planar direction) from 30°C to 250°C is calculated. The obtained value is taken as the value of the linear thermal expansion coefficient.

[0013] (Method for measuring dielectric loss tangent (Df)) A thermosetting resin composition is prepared containing 80 parts by mass of a siloxane-modified maleimide compound, 20 parts by mass of a biphenyl aralkyl novolac-type epoxy resin, 150 parts by mass of molten spherical silica, and 0.5 parts by mass of isocyanate maximidazole. A prepreg is prepared by impregnating a fiber substrate with the thermosetting resin composition and then heating and drying it at 120°C for 5 minutes. Ten layers of the prepreg are stacked to form a laminate, and 12 μm thick copper foil is placed on the top and bottom of the laminate so that the M-side (matte side) is in contact with the prepreg. A double-sided copper-clad laminate is then prepared by heating and pressing it at a temperature of 240°C, a pressure of 3.0 MPa, and a time of 90 minutes. The copper foil is removed from the double-sided copper-clad laminate by immersion in a copper etching solution. The obtained resin plate is cut to a width of 2 mm and a length of 50 mm to be used as an evaluation substrate. Next, the dielectric loss tangent (Df) of the test specimen is measured in accordance with the cavity resonator perturbation method at an ambient temperature of 25°C and in the 10 GHz band.

[0014] When the linear thermal expansion coefficient and dielectric loss tangent (Df) obtained according to the above measurement method are within the predetermined range, the cured prepreg exhibits excellent drillability and a low relative permittivity (Dk). A more detailed method for measuring the linear thermal expansion coefficient and dielectric loss tangent (Df) is described in the examples.

[0015] The linear thermal expansion coefficient obtained according to the above measurement method is 4.6 to 5.4 ppm / °C, but from the viewpoint of improving drillability and reducing the dielectric constant (Dk), it is preferably 4.7 to 5.3 ppm / °C, more preferably 4.8 to 5.2 ppm / °C, and even more preferably 4.9 to 5.1 ppm / °C.

[0016] The dielectric loss tangent (Df) obtained according to the above measurement method is 0.0050 to 0.0070, but from the viewpoint of improving drillability and reducing the relative permittivity (Dk), it is preferably 0.0052 to 0.0068, more preferably 0.0055 to 0.0065, and even more preferably 0.0057 to 0.0062.

[0017] (Fiber base material) The fiber base material contained in the prepreg of this embodiment will be described below. The fiber base material is preferably a sheet-like fiber base material. The fiber base material may have the shape of a woven fabric, nonwoven fabric, robbing, chopped strand mat or surfacing mat, but it is preferably a woven fabric. The fiber base material is preferably glass cloth.

[0018] The thickness of the fibrous base material is preferably 5 to 200 μm, but may also be 10 to 150 μm, 40 to 150 μm, 60 to 130 μm, or 75 to 110 μm. By keeping the thickness of the fibrous base material below the above upper limit, it tends to reduce dimensional changes due to temperature changes, moisture absorption, etc., during the manufacturing process.

[0019] From the viewpoint of improving drillability and reducing the dielectric constant (Dk), the SiO in the glass cloth ２The content of is preferably 61% by mass or less, more preferably 50 to 61% by mass, even more preferably 53 to 60% by mass, and may also be 55 to 59% by mass or 56 to 58% by mass, based on the total amount of glass cloth. ２ O ３ The content of is not particularly limited and may be 0.5 to 30% by mass, 2 to 28% by mass, 5 to 26% by mass, 10 to 26% by mass, 15 to 26% by mass, or 20 to 25% by mass. The content of CaO in the glass cloth is not particularly limited and may be 0 to 10% by mass, 0 to 5% by mass, 0 to 1% by mass, or 0 to 0.1% by mass. The content of MgO in the glass cloth is not particularly limited and may be 0 to 20% by mass, 1 to 18% by mass, 3 to 15% by mass, 5 to 15% by mass, 5 to 15% by mass, or 10 to 15% by mass. ２ O ３ The content is not particularly limited and may be 0 to 25% by mass, 0 to 20% by mass, 0 to 10% by mass, 0 to 5% by mass, 0 to 1% by mass, 0 to 0.1% by mass, or 0 to 0.05% by mass. ２ O and K ２ The total oxygen content is not particularly limited and may be 0 to 5% by mass, 0 to 3% by mass, or 0 to 1% by mass. Using such glass cloth tends to make it easier for the linear thermal expansion coefficient and dielectric loss tangent (Df) to satisfy the aforementioned ranges. As for commercially available glass cloth, the V-glass series manufactured by Nitto Boseki Co., Ltd. can be used.

[0020] The prepreg of this embodiment preferably further comprises (A) a thermosetting resin composition containing a thermosetting resin or a semi-cured product thereof. The semi-cured product of the thermosetting resin composition is obtained by B-stage formation of the thermosetting resin composition. Hereinafter, B-stage formation refers to bringing the material to the B-stage state as defined in JIS K6900 (1994). The prepreg can be manufactured, for example, by impregnating or coating a fibrous substrate with the varnish-like thermosetting resin composition of this embodiment, and then heating and drying it to appropriately semi-cure (B-stage) the thermosetting resin composition.

[0021] As a method for impregnating or coating a fibrous substrate with a thermosetting resin composition, the following hot melt method or solvent method can be employed. The hot melt method does not involve the thermosetting resin composition containing an organic solvent, and involves (1) first coating the thermosetting resin composition onto coated paper with good release properties and then laminating it onto the fibrous substrate, or (2) directly coating the fibrous substrate with a die coater. On the other hand, the solvent method involves including an organic solvent in the thermosetting resin composition, impregnating the fibrous substrate with the thermosetting resin composition by immersing it in the resulting thermosetting resin composition, and then drying it.

[0022] The manufacturing conditions for the prepreg are not particularly limited, but if the solvent method is used, it is preferable that 80% or more by mass of the organic solvent used in the resin varnish volatilizes in the resulting prepreg. The drying temperature after impregnation or coating of the fibrous substrate with the thermosetting resin composition is preferably 80 to 180°C, more preferably 100 to 140°C, and the drying time is appropriately set in consideration of the gelation time of the thermosetting resin composition.

[0023] The solid content derived from the thermosetting resin composition in the prepreg of this embodiment is not particularly limited, but is preferably 30 to 90% by mass, more preferably 35 to 80% by mass, even more preferably 40 to 70% by mass, and particularly preferably 45 to 60% by mass. When the solid content derived from the thermosetting resin composition in the prepreg is within the above range, good moldability tends to be obtained when it is made into a laminate.

[0024] The thickness of the prepreg in this embodiment is not particularly limited and may be 10 to 200 μm, 10 to 150 μm, or 10 to 100 μm.

[0025] (Thermosetting resin composition) Next, the components that the thermosetting resin composition may contain will be described. <(A) Thermosetting resin> Examples of component (A) include epoxy resin, polyimide resin, maleimide compound, phenol resin, polyphenylene ether resin, bismaleimidotriazine resin, cyanate resin, isocyanate resin, benzoxazine resin, oxetane resin, amino resin (e.g., melamine resin), unsaturated polyester resin, allyl resin, dicyclopentadiene resin, silicone resin, etc. Among these, epoxy resin, polyimide resin, maleimide compound, phenol resin, polyphenylene ether resin, cyanate resin, and isocyanate resin are preferred as component (A), and epoxy resin and maleimide compound are more preferred. Component (A) may be used alone or two or more may be used in combination.

[0026] (Epoxy resin) The epoxy resin is preferably an epoxy resin having two or more epoxy groups in one molecule. Here, epoxy resins are classified into glycidyl ether type epoxy resins, glycidylamine type epoxy resins, glycidyl ester type epoxy resins, etc. Among these, glycidyl ether type epoxy resins are preferred. Epoxy resins are classified into various types based on differences in their main skeleton. Within each of these types of epoxy resins, further classifications are made into bisphenol-type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, and bisphenol S type epoxy resin; alicyclic epoxy resins such as dicyclopentadiene type epoxy resin; aliphatic chain epoxy resins; novolac-type epoxy resins such as phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, bisphenol F novolac type epoxy resin, phenol aralkyl novolac type epoxy resin, and biphenyl aralkyl novolac type epoxy resin; stilbene type epoxy resin; naphthalene skeleton-containing epoxy resins such as naphthol novolac type epoxy resin and naphthol aralkyl type epoxy resin; biphenyl type epoxy resin; xylylene type epoxy resin; and dihydroanthracene type epoxy resin. Among these, novolac-type epoxy resins and naphthalene skeleton-containing epoxy resins are preferred as epoxy resins from the viewpoint of solder heat resistance, electrical insulation reliability, and copper foil peel strength, novolac-type epoxy resins are more preferred, and biphenylaralkyl novolac-type epoxy resins are even more preferred.

[0027] The weight-average molecular weight (Mw) of the epoxy resin may be 200 to 2,000, 250 to 1,500, 300 to 1,300, 500 to 1,300, or 800 to 1,200. In this specification, the weight-average molecular weight is a value calculated from a calibration curve using standard polystyrene by gel permeation chromatography (GPC), and more specifically, a value obtained by the method described in the examples. If the weight-average molecular weight of the epoxy resin is above the lower limit, it tends to have excellent solder heat resistance, and if it is below the upper limit, it tends to exhibit low elasticity and flexibility. From the viewpoint of compatibility, the epoxy equivalent of the epoxy resin may be 150 to 500 g / eq, 150 to 450 g / eq, 200 to 350 g / eq, or 240 to 320 g / eq.

[0028] (Maleimide compound) The maleimide compound preferably includes at least one selected from the group consisting of maleimide compounds and derivatives thereof having one or more (preferably two or more) N-substituted maleimide groups. Maleimide compounds having one or more N-substituted maleimide groups are not particularly limited, but preferably aromatic maleimide compounds having one N-substituted maleimide group bonded to an aromatic ring, such as N-phenylmaleimide, N-(2-methylphenyl)maleimide, N-(4-methylphenyl)maleimide, N-(2,6-dimethylphenyl)maleimide, N-(2,6-diethylphenyl)maleimide, N-(2-methoxyphenyl)maleimide, N-benzylmaleimide; 4,4'-diphenylmethanebismaleimide, bis(4-maleimidophenyl) ether, bis(4-maleimidophenyl) sulfone, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethanebismaleimide, 4-methyl-1,3 Examples include aromatic bismaleimide compounds having two N-substituted maleimide groups preferably bonded to an aromatic ring, such as -phenylenebismaleimide, m-phenylenebismaleimide, 2,2-bis[4-(4-maleimidophenoxy)phenyl]propane, and indan ring-containing aromatic bismaleimide; aromatic polymaleimide compounds having three or more N-substituted maleimide groups preferably bonded to an aromatic ring, such as polyphenylmethanemaleimide and biphenylaralkyl-type maleimide; and aliphatic maleimide compounds such as N-dodecylmaleimide, N-isopropylmaleimide, and N-cyclohexylmaleimide, 1,6-bismaleimide-(2,2,4-trimethyl)hexane, and pyrophosphate binder-type long-chain alkylbismaleimide. Among these, from the viewpoint of compatibility with other resins, copper foil peel strength, solder heat resistance, low thermal expansion, and mechanical properties, aromatic bismaleimide compounds having two N-substituted maleimide groups bonded to an aromatic ring are preferred, more preferably 4,4'-diphenylmethanebismaleimide, 2,2-bis[4-(4-maleimidephenoxy)phenyl]propane, and indan ring-containing aromatic bismaleimide, and even more preferably 2,2-bis[4-(4-maleimidephenoxy)phenyl]propane.Furthermore, in the maleimide compound, it is preferable that the nitrogen atoms of the "preferably one N-substituted maleimide group bonded to the aromatic ring," the "preferably two N-substituted maleimide groups bonded to the aromatic ring," and the "preferably three or more N-substituted maleimide groups bonded to the aromatic ring" are all bonded to the aromatic ring. Thus, in the maleimide compound, it is preferable that the nitrogen atoms of the N-substituted maleimide groups are bonded to each other via a linking group that includes the aromatic ring.

[0029] Examples of derivatives of maleimide compounds include addition reaction products of a maleimide compound having one or more (preferably two or more) N-substituted maleimide groups and one or more amine compounds selected from the group consisting of monoamine compounds and diamine compounds. Examples of the monoamine compounds include monoamine compounds having acidic substituents such as o-aminophenol, m-aminophenol, p-aminophenol, o-aminobenzoic acid, m-aminobenzoic acid, p-aminobenzoic acid, o-aminobenzenesulfonic acid, m-aminobenzenesulfonic acid, p-aminobenzenesulfonic acid, 3,5-dihydroxyaniline, and 3,5-dicarboxyaniline. The diamine compounds include 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylethane, 4,4'-diaminodiphenylpropane, 2,2'-bis(4,4'-diaminodiphenyl)propane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-diethyl-4,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylethane, 3,3'-diethyl-4,4'-diaminodiphenylethane, 4,4'-diaminodiphenyl ether, and 4,4'- Examples include aromatic diamines such as diaminodiphenylthioether, 3,3'-dihydroxy-4,4'-diaminodiphenylmethane, 2,2',6,6'-tetramethyl-4,4'-diaminodiphenylmethane, 3,3'-dichloro-4,4'-diaminodiphenylmethane, 3,3'-dibromo-4,4'-diaminodiphenylmethane, 2,2',6,6'-tetrachloro-4,4'-diaminodiphenylmethane, and 2,2',6,6'-tetrabromo-4,4'-diaminodiphenylmethane; siloxanediamines; and the like. The aromatic diamines are compounds in which a primary amino group is substituted on an aromatic ring. The siloxanediamines are silicone compounds having a primary amino group at the terminal.

[0030] A preferred embodiment of the maleimide compound derivative is a so-called siloxane-modified maleimide compound, which is an addition product of a maleimide compound having one or more (preferably two or more) N-substituted maleimide groups with a siloxanediamine. Preferably, the siloxane-modified maleimide compound is an addition product of an aromatic bismaleimide compound having two N-substituted maleimide groups bonded to an aromatic ring with a siloxanediamine; more preferably, an addition product of 4,4'-diphenylmethanebismaleimide, 2,2-bis[4-(4-maleimoidphenoxy)phenyl]propane or an indan ring-containing aromatic bismaleimide with 3,3'-diethyl-4,4'-diaminodiphenylmethane and siloxanediamine; and even more preferably, an addition product of 2,2-bis[4-(4-maleimoidphenoxy)phenyl]propane with 3,3'-diethyl-4,4'-diaminodiphenylmethane and siloxanediamine. The weight-average molecular weight (Mw) of the siloxane-modified maleimide compound is not particularly limited, but is preferably 400 to 10,000, more preferably 1,000 to 5,000, even more preferably 1,500 to 4,000, and particularly preferably 2,000 to 3,500.

[0031] (Content of component (A)) The content of component (A) is preferably 10 to 80 parts by mass, more preferably 15 to 65 parts by mass, even more preferably 20 to 55 parts by mass, and particularly preferably 25 to 55 parts by mass, based on 100 parts by mass of the total solid content in the thermosetting resin composition. When the content of component (A) is within the above range, high copper foil peel strength and high solder heat resistance tend to be obtained.

[0032] <(B) Filler> The thermosetting resin composition of this embodiment may further contain a (B) filler. The (B) filler is not particularly limited, but an inorganic filler is preferred from the viewpoint of ensuring low thermal expansion and flame retardancy. Examples of inorganic fillers include silica, alumina, titanium oxide, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, calcium oxide, magnesium oxide, aluminum nitride, aluminum borate whiskers, boron nitride, silicon carbide, etc. One type of (B) filler may be used alone, or two or more types may be used in combination. Among these, silica is preferred as the (B) filler because it has a low dielectric constant and a low coefficient of linear expansion. Examples of silica include synthetic silica synthesized by a wet or dry method, crushed silica, fused silica, etc.

[0033] (B) The filler may be a filler that has undergone coupling treatment. A silane coupling agent is preferred as the coupling agent used in the coupling treatment. Examples of silane coupling agents include aminosilane coupling agents, epoxysilane coupling agents, phenylsilane coupling agents, alkylsilane coupling agents, alkenylsilane coupling agents, alkynylsilane coupling agents, and silicone oligomer coupling agents. These may be used individually or in combination of two or more.

[0034] The average particle size of component (B) is preferably 0.1 to 2.5 μm, more preferably 0.2 to 1.5 μm, and even more preferably 0.3 to 0.8 μm. If the average particle size of component (B) is above the lower limit, the filler tends to disperse easily in the resin varnish, making aggregation less likely. If it is below the upper limit, sedimentation of component (B) tends to be less likely in the resin varnish. Here, the average particle size in this embodiment refers to the particle size at the point corresponding to 50% of the volume when the cumulative frequency distribution curve by particle size is calculated with the total volume of particles as 100%, and can be measured using a particle size distribution measuring device using laser diffraction scattering or the like.

[0035] (Content of component (B)) When the thermosetting resin composition of this embodiment contains component (B), the content of component (B) is not particularly limited, but is preferably 10 to 100 parts by mass, more preferably 20 to 90 parts by mass, even more preferably 30 to 80 parts by mass, particularly preferably 40 to 75 parts by mass, and most preferably 45 to 70 parts by mass, per 100 parts by mass of the total solid content of the thermosetting resin composition. If the content of component (B) is above the lower limit, the low thermal expansion property tends to be high and sufficient solder heat resistance tends to be obtained. If the content of component (B) is below the upper limit, the copper foil peel strength and solder heat resistance, etc., that component (A) possesses tend to be easily obtained.

[0036] <(C) Curing Accelerator> The thermosetting resin composition of this embodiment may contain (C) a curing accelerator. Component (C) may be used alone or in combination of two or more. For example, if component (A) contains an epoxy resin, component (C) is not particularly limited, but it is preferable to include one or more selected from the group consisting of amine compounds and imidazole compounds, and more preferably an imidazole compound. Examples of the amine compound include dicyandiamide, diaminodiphenylethane, and guanylurea. Examples of the imidazole compounds include 2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate, benzimidazole, and isocyanate-masquimidazole (for example, an addition product of hexamethylene diisocyanate resin and 2-ethyl-4-methylimidazole).

[0037] (Content of component (C)) When the thermosetting resin composition of this embodiment contains component (C), the content of component (C) is not particularly limited, but is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 2 parts by mass, and even more preferably 0.1 to 1 part by mass, per 100 parts by mass of component (A).

[0038] <Other Components> The thermosetting resin composition of this embodiment may or may not contain, as necessary, crosslinking agents such as melamine resins, flame retardants, flame retardant aids, rubber-based elastomers, conductive particles, coupling agents, flow regulators, antioxidants, heat stabilizers, antistatic agents, pigments, leveling agents, defoaming agents, ion trap agents, etc. Known ones can be used for these other components. When the thermosetting resin composition of this embodiment contains the above other components, the content thereof is preferably 0.1 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, and still more preferably 0.1 to 3 parts by mass, respectively, based on 100 parts by mass of the component (A).

[0039] The thermosetting resin composition of this embodiment may be used in a state dissolved or dispersed in an organic solvent, namely, in a state of so-called "resin varnish". Hereinafter, the thermosetting resin composition containing an organic solvent may be referred to as resin varnish. Examples of the organic solvent include ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; aromatic hydrocarbon solvents such as toluene and xylene; ester solvents such as methoxyethyl acetate, ethoxyethyl acetate, butoxyethyl acetate, and ethyl acetate; amide solvents such as N-methylpyrrolidone, formamide, N-methylformamide, and N,N-dimethylacetamide; alcohol solvents such as methanol, ethanol, ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, propylene glycol monopropyl ether, and dipropylene glycol monopropyl ether. The organic solvent may be used alone or in combination of two or more. The solid content concentration in the varnish is preferably 10 to 70% by mass, more preferably 20 to 65% by mass, still more preferably 35 to 65% by mass, and particularly preferably 45 to 65% by mass.

[0040] [Laminates, Metal-Clad Laminates] The laminate of this embodiment is a laminate containing a cured product of the prepreg of this embodiment. Here, the laminate of this embodiment is also a laminate containing a cured product of the thermosetting resin composition. Furthermore, the metal-clad laminate of this embodiment is a metal-clad laminate containing metal foil and a cured product of the prepreg of this embodiment. Here, the metal-clad laminate of this embodiment is also a metal-clad laminate containing metal foil and a cured product of the thermosetting resin composition of this embodiment. The metal-clad laminate can be manufactured, for example, by overlapping the adhesive surfaces on both sides of one prepreg of this embodiment or on both sides of a laminate of two or more (preferably 2 to 20) prepregs with the metal foil, and then heating and pressurizing it by vacuum pressing at a pressure of 0.5 to 10 MPa, preferably 1 to 5 MPa, preferably at 130 to 260°C, more preferably 180 to 250°C, and even more preferably 210 to 250°C.

[0041] Examples of metal foils used in metal-clad laminates include copper foil, aluminum foil, tin foil, tin-lead alloy (solder) foil, and nickel foil. In addition, composite foils with a three-layer structure, in which nickel, nickel-phosphorus, nickel-tin alloy, nickel-iron alloy, lead, or lead-tin alloy are used as an intermediate layer and copper layers of 0.5 to 15 μm and 10 to 300 μm are provided on both sides, and composite foils with a two-layer structure, in which aluminum and copper foil are combined, can be used. Copper foil and aluminum foil are preferred as metal foils, with copper foil being more preferred. The thickness of the metal foil can be the thickness generally used for laminates, for example, 1 to 200 μm.

[0042] In the laminate and metal-clad laminate of this embodiment, the prepreg (more specifically, the thermosetting resin composition in the prepreg) is C-staged and cured. In other words, the laminate of this embodiment contains C-staged prepreg, and the metal-clad laminate of this embodiment can be said to contain C-staged prepreg and metal foil. Hereinafter, C-staged means bringing the material to the C-stage state as defined in JIS K6900 (1994).

[0043] [Printed Wiring Board] The printed wiring board of this embodiment includes the laminate or metal-clad laminate of this embodiment. The printed wiring board of this embodiment does not necessarily include the laminate or metal-clad laminate as it is. For example, it also includes cases where circuit formation processes such as drilling, metal plating, and etching of metal foil are performed on the laminate or metal-clad laminate. The printed wiring board of this embodiment can be manufactured by performing circuit formation processes such as drilling, metal plating, and etching of metal foil on the laminate or metal-clad laminate of this embodiment by known methods, and further performing multilayer processing as necessary.

[0044] [Semiconductor Package] The semiconductor package of this embodiment includes the printed wiring board of this embodiment and a semiconductor element. In other words, the semiconductor package of this embodiment is formed by mounting a semiconductor element on the printed wiring board of this embodiment. The semiconductor package of this embodiment can be manufactured, for example, by mounting semiconductor elements such as semiconductor chips and memories on a predetermined position of the printed wiring board of this embodiment by known methods and sealing the semiconductor elements with a sealing resin or the like.

[0045] Hereinafter, the present embodiment will be specifically described with reference to examples. However, the present embodiment is not limited to the following examples.

[0046] In each example, the weight-average molecular weight (Mw) was measured by the following method: Gel permeation chromatography (GPC) was used to calculate the molecular weight from a calibration curve using standard polystyrene. The calibration curve was approximated by a cubic equation using standard polystyrene: TSK standard POLYSTYRENE (Type; A-2500, A-5000, F-1, F-2, F-4, F-10, F-20, F-40) [manufactured by Tosoh Corporation]. The GPC measurement conditions are shown below. Equipment: Pump: L-6200 [Hitachi High-Technologies Corporation] Detector: L-3300 RI [Hitachi High-Technologies Corporation] Column Oven: L-655A-52 [Hitachi High-Technologies Corporation] Column: Guard column; "TSK Guardcolumn HHR-L" + Column; "TSKgel G4000HHR" + "TSKgel G2000HHR" (all manufactured by Tosoh Corporation) Column size: 6.0 × 40 mm (guard column), 7.8 × 300 mm (column) Eluent: Tetrahydrofuran Sample concentration: 30 mg / 5 mL Injection volume: 20 μL Flow rate: 1.00 mL / min Measurement temperature: 40°C

[0047] [Production Example 1: Production of Siloxane-Modified Maleimide Compound] In a 5 L reaction vessel capable of heating and cooling, equipped with a thermometer, a stirrer, and a moisture meter with a reflux condenser, 100 parts by mass of 2,2-bis[4-(4-maleimidophenoxy)phenyl]propane, 5.6 parts by mass of a silicone compound having primary amino groups at both ends (primary amino group equivalent 750 g / mol), 7.9 parts by mass of 3,3'-diethyl-4,4'-diaminodiphenylmethane, and 171 parts by mass of propylene glycol monomethyl ether were added, and the mixture was reacted under reflux for 2 hours. The resulting reaction solution was concentrated at reflux temperature over 3 hours to obtain a solution of siloxane-modified maleimide compound with a solid content of 65% by mass. The weight-average molecular weight (Mw) of the obtained siloxane-modified maleimide compound was approximately 2,700.

[0048] Example 1 (Fiber base material: V-glass) (Preparation of thermosetting resin composition and resin varnish) Each component shown in Table 1 was blended in the amounts shown in Table 1 (the amounts listed in Table 1 are in parts by mass of solids) and mixed in methyl ethyl ketone to obtain a thermosetting resin composition (resin varnish) with a non-volatile content (solids concentration) of 60% by mass. (Preparation of prepreg) The resin varnish prepared above was impregnated into V-glass "V2118" (thickness: approximately 90 μm) manufactured by Nitto Boseki Co., Ltd., and then heated at 120°C for 5 minutes and dried to obtain a prepreg. (Preparation of double-sided copper-clad laminates) Ten layers of the aforementioned prepreg were stacked, and 12 μm thick electrolytic copper foil "3EC-M3-VLP-12" (manufactured by Mitsui Mining & Smelting Co., Ltd.) was placed on top and bottom of the laminate so that the M-side (roughened side) was aligned with the prepreg. Double-sided copper-clad laminates were then prepared by heating and pressurizing the laminate at 240°C and 3 MPa for 90 minutes under vacuum press conditions. The obtained double-sided copper-clad laminates were used for the following measurements and evaluations according to the measurement and evaluation methods described below. The results are shown in Table 1.

[0049] Comparative Example 1 (Fiber Substrate: T-Glass) In Example 1, the same procedure was followed except that T-Glass "T2118" (thickness: approximately 90 μm) manufactured by Nitto Boseki Co., Ltd. was used instead of V-Glass "V2118". Prepregs and double-sided copper-clad laminates were prepared and evaluated. The results are shown in Table 1.

[0050] Comparative Example 2 (Fiber Substrate: Q Glass) In this comparative example, prepregs and double-sided copper-clad laminates were prepared by performing the same procedure as in Example 1, except that Q glass "Q2116" (quartz glass, thickness: approximately 90 μm) manufactured by Shin-Etsu Chemical Co., Ltd. was used instead of V glass "V2118," and each was evaluated. The results are shown in Table 1.

[0051] [Measurement Method] (I) Linear Thermal Expansion Rate The copper foil was removed from the double-sided copper-clad laminate by immersing it in a 10% by mass solution of ammonium persulfate (manufactured by Mitsubishi Gas Chemical Company, Inc.), which is a copper etching solution. The obtained resin plate was cut into pieces with a width of 5 mm × a length of 5 mm, and then dried at 105°C for 1 hour to obtain an evaluation substrate. For this evaluation substrate, thermomechanical analysis was performed by the tensile method using a thermomechanical measuring device (TMA) [manufactured by TA Instruments Japan Co., Ltd., model Q400]. After mounting the evaluation substrate on the device in the X direction, it was measured once under the measurement conditions of a load of 5 g and a heating rate of 10°C / min. The average linear thermal expansion rate from 30°C to 100°C (average of the linear thermal expansion rates in the plane direction) was calculated and taken as the value of the linear thermal expansion rate.

[0052] (II) Dissipation Factor (Df) The copper foil was removed from the double-sided copper-clad laminate by immersing it in a 10% by mass solution of ammonium persulfate (manufactured by Mitsubishi Gas Chemical Company, Inc.), which is a copper etching solution. The obtained resin plate was cut into pieces with a width of 2 mm × a length of 50 mm, and then dried at 105°C for 1 hour to obtain an evaluation substrate. Then, in accordance with the cavity resonator perturbation method, the dissipation factor (Df) of the test piece was measured at an ambient temperature of 25°C in the 10 GHz band.

[0053] [Evaluation Method] (1) Relative Dielectric Constant (Dk) The copper foil was removed from the double-sided copper-clad laminate by immersing it in a 10% by mass solution of ammonium persulfate (manufactured by Mitsubishi Gas Chemical Company, Inc.), which is a copper etching solution. The obtained resin plate was cut into pieces with a width of 2 mm × a length of 50 mm, and then dried at 105°C for 1 hour to obtain an evaluation substrate. Then, in accordance with the cavity resonator perturbation method, the relative dielectric constant (Dk) of the test piece was measured at an ambient temperature of 25°C in the 10 GHz band.

[0054] (2) Drillability An aluminum foil with a thickness of 0.15 mm was placed on top of three stacked double-sided copper-clad laminates, and a paper phenolic board with a thickness of 1.5 mm was placed below. Then, using a drill hole punching machine (manufactured by Biamechanics Co., Ltd., product name "ND-1V212") equipped with a drill with a diameter of 0.15 mm, at a rotational speed of 200×10 ３10,000 holes were drilled under the following conditions: rpm, feed rate 2 m / min, and chip load 10 μm / rev. The misalignment of the holes on the bottom of the third layer (drill exit side) of a three-layer copper-clad laminate was measured using a hole position accuracy measuring instrument (manufactured by Via Mechanics Co., Ltd., product name "HT-1AM"), and the average misalignment of 10,000 holes + 3σ (σ: standard deviation) was calculated. This value was used as an indicator of drillability. A smaller value indicates better drillability.

[0055]

[0056] The details of the components in Table 1 are as follows: [Component (A)] Maleimide compound 1: Siloxane-modified maleimide compound prepared in Production Example 1 Epoxy resin 1: "EPICLON NC-3000", biphenylaralkyl novolac type epoxy resin (manufactured by Nippon Kayaku Co., Ltd.), weight-average molecular weight: 1,000, epoxy equivalent: 275 g / eq

[0057] [Component (B)] Filler 1: Molten spherical silica, average particle size (D ５０ ) 0.5 μm

[0058] [(C) Ingredients] • Curing accelerator 1: Isocyanate mask imidazole "G-8009L" (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)

[0059] As is clear from Table 1, the double-sided copper-clad laminates using the prepreg of this embodiment exhibited excellent drillability and a low relative permittivity (Dk). On the other hand, Comparative Example 1, which used a prepreg not corresponding to this embodiment, showed excellent drillability, but had a high relative permittivity (Dk). Furthermore, Comparative Example 2, which also used a prepreg not corresponding to this embodiment, showed poor drillability and a high relative permittivity (Dk).

Claims

1. A prepreg containing a fiber substrate, wherein the linear thermal expansion coefficient measured according to the following measurement method is 4.6 to 5.4 ppm / °C, and the dielectric loss tangent (Df) measured according to the following measurement method is 0.0050 to 0.0070. (Method for measuring linear thermal expansion coefficient) A thermosetting resin composition is prepared containing 80 parts by mass of a siloxane-modified maleimide compound, 20 parts by mass of a biphenyl aralkyl novolac-type epoxy resin, 150 parts by mass of molten spherical silica, and 0.5 parts by mass of isocyanate maximidazole. The thermosetting resin composition is impregnated into a fiber substrate and then heated at 120°C for 5 minutes and dried to produce a prepreg. Ten layers of the prepreg are stacked to form a laminate, and 12 μm thick copper foil is placed on the top and bottom of the laminate so that the M-side (matte side) is in contact with the prepreg. Then, a double-sided copper-clad laminate is produced by heating and pressurizing it at a temperature of 240°C, a pressure of 3.0 MPa, and a time of 90 minutes. The copper foil is removed from the resulting double-sided copper-clad laminate by immersion in a copper etching solution. The resulting resin plate is cut to a width of 5 mm and a length of 5 mm to be used as the evaluation substrate. Thermomechanical analysis is performed using the tensile method with a thermomechanical analyzer (TMA). After mounting the evaluation substrate in the X direction on the apparatus, one measurement is taken under measurement conditions of a load of 5 g and a heating rate of 10°C / min. The average thermal expansion coefficient (average of the linear thermal expansion coefficient in the plane direction) from 30°C to 100°C is calculated. The obtained value is taken as the value of the linear thermal expansion coefficient. (Method for measuring dielectric loss tangent (Df)) A thermosetting resin composition is prepared containing 80 parts by mass of a siloxane-modified maleimide compound, 20 parts by mass of a biphenyl aralkyl novolac-type epoxy resin, 150 parts by mass of molten spherical silica, and 0.5 parts by mass of isocyanate maximidazole. A prepreg is prepared by impregnating a fiber substrate with the thermosetting resin composition and then heating and drying it at 120°C for 5 minutes. Ten layers of the prepreg are stacked to form a laminate, and 12 μm thick copper foil is placed on the top and bottom of the laminate so that the M side (matte side) is in contact with the prepreg. A double-sided copper-clad laminate is then prepared by heating and pressing it at a temperature of 240°C, a pressure of 3.0 MPa, and a time of 90 minutes. The copper foil is removed from the double-sided copper-clad laminate by immersion in a copper etching solution. The obtained resin plate is cut to a width of 2 mm and a length of 50 mm to be used as an evaluation substrate.Next, the dielectric loss tangent (Df) of the test specimen is measured in accordance with the cavity resonator perturbation method at an ambient temperature of 25°C and in the 10 GHz band.

2. The prepreg according to claim 1, wherein the fiber base material is glass cloth.

3. SiO in the glass cloth ２ The prepreg according to claim 1, wherein the content of is 61% by mass or less relative to the total amount of glass cloth.

4. The prepreg according to claim 1, further comprising (A) a semi-cured product of a thermosetting resin composition containing a thermosetting resin.

5. The prepreg according to claim 4, wherein component (A) comprises at least one selected from the group consisting of epoxy resin, polyimide resin, maleimide compound, phenol resin, polyphenylene ether resin, bismaleimidotriazine resin, cyanate resin, isocyanate resin, benzoxazine resin, oxetane resin, amino resin, unsaturated polyester resin, allyl resin, dicyclopentadiene resin, and silicone resin.

6. The prepreg according to claim 4, wherein component (A) comprises at least one selected from the group consisting of maleimide compounds having one or more N-substituted maleimide groups and derivatives thereof.

7. The prepreg according to claim 4, wherein component (A) comprises a siloxane-modified maleimide compound.

8. The prepreg according to claim 1, wherein the thermosetting resin composition further contains (B) a filler.

9. The prepreg according to claim 1, wherein the thermosetting resin composition further contains (C) a curing accelerator.

10. A laminate containing a cured prepreg according to claim 1.

11. A metal-clad laminate comprising a metal foil and a cured prepreg according to claim 1.

12. A printed circuit board comprising the laminate according to claim 10 or the metal-clad laminate according to claim 11.

13. A semiconductor package comprising a printed circuit board according to claim 12 and a semiconductor element.

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