JP2004149577A - Prepreg and laminated sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide prepreg forming a laminated sheet reducing breakage or abrasion of a drill during drilling, reducing inner wall roughness and suppressing development of a defective such migration of CAF (conductive anodic filament) when drilling of small-diameter holes is performed. <P>SOLUTION: The air permeability is regulated to 2-4 cm<SP>3</SP>/cm<SP>2</SP>/s by subjecting a glass cloth to at least one treatment of flattening processing and opening processing. The resultant substrate is then impregnated with a thermosetting resin composition containing an inorganic filler in an amount of ≤240 pts. mass based on 100 pts. mass of the total amount of a resin component. The average particle diameter of the inorganic filler is 0.2-3.0 μm. Thereby, the thermosetting resin composition is converted into a B-stage state. <P>COPYRIGHT: (C)2004,JPO

Description

【００５４】
表１の結果から明らかなように、実施例１〜６では良好な成形性と、高い耐熱性とを有し、またドリル摩耗率が低く折損も発生せず、更にホールの内壁粗さも低いものであった。
【００５５】
【発明の効果】
上記のように請求項１に係るプリプレグは、通気度を２〜４ｃｍ^３／ｃｍ^２／ｓｅｃとしたガラスクロスに、樹脂成分の総量１００質量部に対して２４０質量部以下の無機充填材を含有し、且つこの無機充填材の平均粒径が０．２〜３．０μｍである熱硬化性樹脂組成物を含浸し、この熱硬化性樹脂組成物をＢステージ状態として成るため、このようなプリプレグにて積層板を製造すると、積層板の強度が均一化し、スルーホール形成のために小径ドリル加工を施す場合でもドリルに対して過大な負荷がかからなくなってドリル折損を抑制し、またドリルの長寿命化を図ることができるものであり、また、孔あけ加工にて形成される孔の内壁を滑らかに形成することができて、ホール密度が高くなってスルーホールの壁間距離が近くなってもＣＡＦ（Ｃｏｎｄｕｃｔｉｖｅ Ａｎｏｄｉｃ Ｆｉｌａｍｅｎｔｓ）等のマイグレーションの発生を抑制することができるものである。また無機充填材が配合された樹脂ワニスを含浸させて積層板に高い耐熱性と剛性を付与することができると共にこの樹脂ワニスの基材に対する良好な含浸性を確保して積層板の製造にカスレやボイド等の成形不良が発生することを抑制することもできるものである。
【００５６】
また請求項２の発明は、無機充填材として、粒子形状が略球形状であるシリカを用いるため、プリプレグにて形成される積層板の誘電率を低減すると共にこの積層板の吸水率を低減して性能劣化を抑制することができ、またプリプレグ成形時における組成物の流動性を更に向上でき、更にドリル孔あけ加工時における加工用ドリルの摩耗や折損の発生を更に抑制することができるものである。
【００５７】
また請求項３の係る積層板は、請求項１又は２に記載のプリプレグの所要枚数と金属箔とを積層一体化して成るため、強度が均一化し、スルーホール形成のために小径ドリル加工を施す場合でもドリルに対して過大な負荷がかからなくなってドリル折損を抑制し、またドリルの長寿命化を図ることができるものであり、また、孔あけ加工にて形成される孔の内壁を滑らかに形成することができて、ホール密度が高くなってスルーホールの壁間距離が近くなってもＣＡＦ等のマイグレーションの発生を抑制することができるものである。また積層板の製造にカスレやボイド等の成形不良が発生することを抑制すると共に積層板に高い耐熱性を付与することもできるものである。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a prepreg used for manufacturing a printed wiring board such as a multilayer printed wiring board, and a laminated board manufactured using the prepreg.
[0002]
[Prior art]
2. Description of the Related Art In recent years, due to the space saving of personal computers, the spread of mobile phones and PDAs (portable information communication terminals), the size and thickness of semiconductor packages to be mounted have been rapidly reduced. At the same time, substrate materials for forming printed wiring boards used in the above equipment are also required to be reduced in weight. By switching from ceramic packages, which have been the mainstream until now, to laminate packages, weight reduction and workability have been achieved. Improvements are being made.
[0003]
When forming a printed wiring board or the like with a laminated board, in order to promote miniaturization, form a multilayer printed wiring board with a layer structure that is further stacked in the height direction, not only to spread the circuit in the surface direction but also to form a layer Can be stacked. At this time, the through holes that have been opened for connection of the front and back circuits in the single-layer laminated board have also played a role of connecting the layers in the multilayer printed wiring board. For this reason, the number of through holes has increased drastically as compared with the related art, and the hole density has increased. Therefore, when drilling a through-hole in a laminated plate by drilling or the like, drilling with a small diameter has been required.
[0004]
However, when small-diameter drilling is used for an existing laminated plate material, drill breakage and drill life become problems. In addition, as the number of holes increases, the distance between the walls of the through holes decreases, and migration such as CAF (Conductive Anodic Filaments) easily occurs. Therefore, in order to ensure high reliability, the hole shape such as the inner wall roughness must be reduced. There was also a need to improve.
[0005]
In other words, when a prepreg is formed using a base material such as glass cloth, the degree of dispersion of glass fibers in the laminate can be considered to be uniform when the hole diameter to be formed is large, but the dispersion of glass fibers is small when the hole diameter is small. The degree of non-uniformity becomes apparent, and the difference in strength between the portion where the glass fiber is arranged and the portion where the glass fiber does not exist in the region where the drilling process is performed. The problem of the hole shape occurred.
[0006]
On the other hand, various proposals have been made to improve the drill workability in forming a through-hole. For example, Patent Document 1 discloses a naphthalene ring-containing epoxy resin as an epoxy resin composition for forming a prepreg or a laminate. By specifying the compounding amount, drill workability is improved from the viewpoint of the resin component, but the problem due to non-uniformity of the fiber of the base material has not been solved.
[0007]
Patent Document 2 describes that the surface layer of the base material forming the prepreg or the laminate is made of a glass fiber base material, and that the center layer is made of aramid fiber to improve the drill workability. As in Patent Document 1, the problem due to non-uniformity of the fibers of the base material has not been solved.
[0008]
In Patent Document 3, it is possible to open and entangle a filament bundle constituting a yarn, and to manufacture a prepreg and a laminated board using a glass woven base material having a limited number of wefts and warps and a basis weight. Although disclosed, the drillability of drilling a small-diameter hole having a diameter of 0.1 μm or less is still insufficient, and a resin containing an inorganic filler for improving heat resistance, rigidity, etc. No consideration was given to the impregnating property when impregnating the varnish, and a laminate having high heat resistance and having small-diameter through holes could not be obtained.
[0009]
Further, in Patent Document 4, a thickness of 50 μm ± 10 μm and a weight of 35 to 60 g / m ² , Air permeability 25cm ³ / Cm ² Using a glass woven fabric of / sec or less, a resin composition containing an inorganic filler is impregnated to produce a prepreg, thereby producing a printed wiring board, and forming a hole in the prepreg by laser processing or drilling. However, even with such a base material, when forming small-diameter holes, it cannot be said that the glass fibers are sufficiently uniformly dispersed, and the drill workability was insufficient. .
[0010]
[Patent Document 1]
JP-A-5-301941
[Patent Document 2]
JP-A-5-318638
[Patent Document 3]
JP-A-7-243153
[Patent Document 4]
JP 2001-196492 A
[0011]
[Problems to be solved by the invention]
The present invention has been made in view of the above points, and when performing small-diameter hole drilling, reduces breakage and wear of the drill during drilling, and reduces inner wall roughness to reduce CAF and the like. A prepreg which can form a laminate capable of suppressing the occurrence of defects, has excellent impregnating properties when impregnating a base material with a resin varnish blended with an inorganic filler, and has suppressed molding defects, and using this prepreg It is an object of the present invention to provide a laminate formed by the above method.
[0012]
[Means for Solving the Problems]
The prepreg according to claim 1 has an air permeability of 2 to 4 cm by performing at least one of flattening and opening processing on the glass cloth. ³ / Cm ² / Sec, the base material contains 240 parts by mass or less of the inorganic filler based on 100 parts by mass of the total amount of the resin component, and the average particle size of the inorganic filler is 0.2 to 3.0 μm. The thermosetting resin composition is impregnated with the thermosetting resin composition to form a B-stage state.
[0013]
The invention of claim 2 is characterized in that, in claim 1, silica having a substantially spherical particle shape is used as the inorganic filler.
[0014]
According to a third aspect of the present invention, there is provided a laminated plate wherein a required number of prepregs according to the first or second aspect and a metal foil are laminated and integrated.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described.
[0016]
In the present invention, as a base material for forming a prepreg, by performing one or both of flattening and spreading processing on a glass cloth, the air permeability thereof is 2 to 4 cm. ³ / Cm ² / Sec is used. This air permeability is measured using a Frazier tester according to JIS R3420.
[0017]
As the glass cloth before the flattening processing or the fiber opening processing is performed, an appropriate glass cloth is used, and the air permeability obtained by weaving a strand composed of a plurality of filaments is 10 to 15 cm. ³ / Cm ² / Sec is preferably used. Specifically, for example, a yarn (E225) composed of 22 filaments having a diameter of 7 μm is woven so that the number of warps and wefts per 2.54 cm square (1 inch square) is 60 × 49, and the thickness is 0. 0.086 mm, basis weight 92 g / m ² 2319 type (IPC-EG-140) glass cloth can be used.
[0018]
Such flattening of the glass cloth can be performed, for example, by continuously pressing the glass cloth with an appropriate pressure (for example, a linear pressure of 300 N / cm) with a press roll to compress the yarn flatly. In the fiber opening process, for example, a high-pressure water spray is applied to a glass cloth at an appropriate pressure (eg, 200 N / cm). ² ) To loosen the yarn. In particular, it is preferable to use a glass cloth that has been subjected to flattening processing and then subjected to fiber opening processing.
[0019]
Here, it is preferable to use a substrate having a thickness of 0.1 mm or less. That is, when the thickness of the base material is reduced to reduce the diameter of the fiber (yarn) constituting the base material, the surface smoothness of the base material is easily obtained, and fine pattern circuit formation and high density It is suitable for mounting, and can be suitably used particularly in portable electronic devices and devices that are required to be light and thin. The lower limit of the thickness of the base material is not particularly limited, but is preferably 0.04 mm or more in consideration of handleability.
[0020]
Further, the thermosetting resin composition to be impregnated into the base material contains a thermosetting resin and an inorganic filler, and further contains a curing agent, a curing accelerator, a crosslinking agent, and other additives as necessary. Things are used.
[0021]
As the thermosetting resin, an appropriate resin generally used for manufacturing a prepreg for forming a wiring board can be used.For example, an epoxy resin, a polyfunctional cyanate resin, a polyfunctional maleimide-cyanate resin, Examples thereof include a polyfunctional maleimide resin and an unsaturated polyphenylene ether resin. These resins can be used alone or in combination of two or more.
[0022]
When using an epoxy resin as the thermosetting resin, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, isocyanurate type epoxy resin, Hydantoin type epoxy resin, alicyclic epoxy resin, biphenyl type epoxy resin, polyfunctional epoxy resin and the like can be mentioned, and these epoxy resins can be used alone or in combination of two or more.
[0023]
When a polyfunctional cyanate ester resin is used as the thermosetting resin, any compound having two or more cyanate groups in the molecule may be used. Specifically, 1,3- or 1,4-dicyanate is used. Benzene, 1,3,5-tricyanate benzene, 1,3-, 1,4-, 1,6-, 1,8-, 2,6- or 2,7-dicyanate naphthalene, 1,3,6 -Tricyanate naphthalene, 4,4-dicyanate biphenyl, bis (4-dicyanate phenyl) methane, 2,2-bis (4-cyanate phenyl) propane, 2,2-bis (3,5-dibromo-4- (Cyanate phenyl) thioether, bis (4-cyanate phenyl) sulfone, tris (4-cyanate phenyl) phosphite and the like.
[0024]
The curing agent is added as needed depending on the type of the thermosetting resin, and an appropriate one generally used conventionally can be used. For example, when an epoxy resin is used as the thermosetting resin, there is no particular limitation as long as it can be used as a curing agent for the epoxy resin. For example, amine curing agents such as primary amine and secondary amine, bisphenol A and Examples thereof include phenol-based curing agents such as bisphenol F, and acid anhydride-based curing agents. These curing agents can be used alone or in combination of two or more. This curing agent is preferably blended in a stoichiometric equivalent ratio to the epoxy resin in the range of 0.05 to 0.2 equivalent.
[0025]
As the inorganic filler, any material having electrical insulation properties can be used without particular limitation.Examples include silica, talc, calcined talc, aluminum hydroxide, magnesium hydroxide, kaolin, and alumina. One type may be used alone, or two or more types may be used in combination.
[0026]
The amount of the inorganic filler is 240 parts by mass or less with respect to 100 parts by mass of the resin component in the composition. It is possible to suppress occurrence of molding failure and to impart high heat resistance to the laminate. Here, the resin component refers to a thermosetting resin in the composition, and when a curing agent and a curing accelerator are added, these are combined. In particular, the amount is preferably 200 parts by mass or less. The amount of the inorganic filler is preferably 80 parts by mass or more with respect to 100 parts by mass of the resin component in the composition. In this case, the laminate formed of the prepreg has excellent heat resistance and high heat resistance. Sufficient rigidity as a rigid material can be provided.
[0027]
Further, the average particle size of the inorganic filler is set to be in a range of 0.2 to 3.0 μm, and by setting the average particle size to 3.0 μm or less, a drill for a laminate obtained by a prepreg is used. Further suppresses abrasion of the drill during drilling and further suppresses breakage of the drill, and suppresses aggregation of the inorganic filler in the thermosetting resin composition by making the average particle diameter 0.2 μm or more. However, sufficient fluidity of the composition at the time of prepreg molding can be ensured, and the occurrence of molding defects such as fraying is further suppressed.
[0028]
In addition, as the inorganic filler, it is preferable to use, as a part or the whole thereof, silica whose particle shape is substantially spherical. For this reason, it is preferable to use fused silica. When silica is used as the inorganic filler in this manner, the dielectric constant of the laminate formed of the prepreg can be reduced as compared with the case where only a metal hydroxide such as aluminum hydroxide or magnesium hydroxide is used. Further, the water absorption rate can be reduced as compared with the case where only talc, clay, or the like is used, and the performance deterioration of the laminated board can be suppressed. Further, by using a particle having a substantially spherical shape, the fluidity of the composition at the time of prepreg molding can be further improved than when using a non-spherical particle such as crushed silica, and drilling. It is possible to further suppress the occurrence of wear and breakage of the working drill during working. In order to obtain such an effect, it is preferable that the content of the silica having a substantially spherical particle shape be 50 to 100% by mass based on the total amount of the inorganic filler.
[0029]
In preparing the thermosetting resin composition having the composition described above, a general method for preparing a thermosetting resin composition can be applied.For example, the above components, and various additives as necessary. A predetermined amount is blended and uniformly mixed with a disperser or a mill, whereby a thermosetting resin composition can be obtained.
[0030]
When a prepreg is manufactured using the above-described base material and thermosetting resin composition, a general prepreg manufacturing method can be applied.For example, the base material is impregnated with the thermosetting resin composition, and then heated. The thermosetting resin composition is dried and semi-cured so as to be in the B-stage state. The heating conditions at this time are appropriately set depending on the composition of the thermosetting resin composition and the like. For example, heating is performed at 150 to 170 ° C. for 4 to 7 minutes.
[0031]
Here, as a method of impregnating the base material with the thermosetting resin composition, a known appropriate method can be employed. For example, the resin is obtained by dispersing and dissolving the thermosetting resin composition in an appropriate organic solvent. A varnish can be prepared and the resin varnish can be impregnated into a substrate. In this case, examples of the organic solvent include aromatic hydrocarbons such as toluene, xylene, and benzene, ketones, and alcohols. The organic solvents can be used alone or in combination of two or more.
[0032]
The resin content of the prepreg may be appropriately set according to the thickness of the base material, the purpose of use of the prepreg, and the like, and may be, for example, in the range of 45 to 65%.
[0033]
Also, when manufacturing a laminate using a prepreg, a general method for manufacturing a laminate using a prepreg can be applied. For example, for a single prepreg or a plurality of prepregs stacked, a metal foil such as a copper foil is laminated on one or both surfaces thereof, and the thermosetting resin composition in the prepreg is cured by heat and pressure molding. In addition to forming the insulating layer, the metal foil and the insulating layer can be integrated. The heating and pressurizing conditions at the time of forming such a laminate can be appropriately set according to the thickness of the laminate to be manufactured, the composition of the thermosetting resin composition used for forming the prepreg, and the like. To 210 ° C., a pressure of 3.5 to 4.0 Pa, and a heating and pressing time of 120 to 150 minutes.
[0034]
A printed wiring board can be formed from the obtained laminated board by forming holes for through holes or the like by drilling, plating through holes, or forming a circuit by a subtractive method or the like.
[0035]
In the laminated plate as described above, the air permeability is 2 to 4 cm by subjecting the glass cloth to flattening or opening processing. ³ / Cm ² / Sec, the insulating layer of the laminated board is formed by the prepreg using the base material, and the degree of the density of the fibers in the insulating layer is reduced, and the portion where the fibers overlap in the insulating layer and the fibers The difference in strength from the part where no is present is reduced, and the strength inside the insulating layer is made uniform. For this reason, when drilling a laminated plate to form a through hole, even when drilling a small diameter of 0.1 μm or less, imbalance in stress applied when the drill passes through the laminated plate occurs. It is difficult to prevent breakage of the drill (drill breakage), and it is difficult to generate a portion having excessively high strength in the laminated plate, thereby suppressing wear of the drill and extending the life of the drill. .
[0036]
Here, the lower limit of the hole diameter at the time of drilling is not particularly limited, but at present, the hole diameter that can be formed by drilling is up to 0.05 mm (50 μm). The effect of suppressing breakage of the drill and wear of the drill is sufficiently obtained.
[0037]
In addition, it is possible to prevent the rigid portion in the laminated plate from remaining or the soft portion from being excessively removed in the portion where the hole is formed, and to suppress the roughening of the inner wall of the hole. Therefore, even when the hole density is high, for example, when the distance between the through holes is in the range of 100 to 150 μm, and the distance between the walls of the through holes is short, migration of CAF (Conductive Anodic Filaments) or the like occurs. Can be suppressed.
[0038]
Here, the air permeability of the substrate is 2 cm. ³ / Cm ² The reason for setting to / sec or more is that if the air permeability of the base material becomes excessively small, the amount of voids in the base material decreases, impregnating property during resin impregnation decreases, and molding defects such as frays and residual voids occur during production of a laminate. And the air permeability is 4 cm. ³ / Cm ² When the time exceeds / sec, effects such as reduction of drill breakage and drill wear and suppression of roughening of the inner wall of the hole cannot be sufficiently obtained.
[0039]
Further, the content of the inorganic filler in the thermosetting resin composition in the prepreg is 240 parts by mass or less based on 100 parts by mass of the resin component, and the particle size thereof is 0.2 to 3.0 μm. The filler maintains high heat resistance of the laminate and suppresses a decrease in fluidity due to an excessive blending amount, and has a permeability of 2 to 4 cm. ³ / Cm ² / Sec, the impregnating property of the thermosetting resin composition can be ensured even for a base material having a small porosity, and molding defects such as burrs and voids can be suppressed during the production of a laminate. In addition, by setting the average particle size to 3.0 μm or less, the wear of the working drill during drilling of the laminated plate obtained by the prepreg is further suppressed, the breakage thereof is further suppressed, and the average particle size is reduced to 0. .2 μm or more suppresses aggregation of the inorganic filler in the thermosetting resin composition, secures sufficient fluidity of the composition at the time of prepreg molding, and has an air permeability of 2 to 4 cm. ³ / Cm ² / Sec, a more excellent resin impregnating property is exerted on a base material having a small porosity, and the occurrence of molding defects such as burrs is further suppressed.
[0040]
【Example】
Hereinafter, the present invention will be described in detail with reference to examples.
[0041]
(Examples 1 to 6, Comparative Examples 1 to 7)
A resin varnish was prepared by dispersing and dissolving 100 parts by mass of a thermosetting resin composition having the composition shown in Table 1 in 90 parts by mass of toluene.
[0042]
Further, as the substrate, a glass cloth having a thickness of 0.1 mm or less in which the air permeability was adjusted as shown in Table 1 by performing flattening processing and subsequently performing fiber opening processing on the above-mentioned glass cloth equivalent to 2319 was used. Using.
[0043]
Here, the flattening process is performed by continuously pressing the glass cloth with a press roll at a linear pressure of 300 N / cm to compress the yarn flatly. Water flow 200N / cm ² This was done by injecting at a pressure of
[0044]
Then, for each of Examples and Comparative Examples, the base material was impregnated with the resin varnish, and was heated and dried at 160 ° C. for 4 minutes to be semi-cured to form a prepreg having a resin content of 45%.
[0045]
Next, four prepregs were stacked and copper foils having a thickness of 12 μm were stacked on both sides of the prepregs, and heated and pressed at 200 ° C. and 3.5 MPa for 120 minutes to obtain a double-sided copper-clad laminate having a thickness of 0.4 mm.
[0046]
Here, the resin component in the resin varnish in each of Examples and Comparative Examples was composed of 100 parts by mass of a polymer polyphenylene ether (manufactured by GE Plastics Co., Ltd., product number "Noryl 640-111") and 3.5 parts by mass of bisphenol. A is heated and melted and mixed, and then 4.5 parts by mass of a radical polymerization initiator (manufactured by NOF CORPORATION, benzoyl peroxide) is blended, and polymer polyphenylene ether and bisphenol A are reacted. Prepared modified phenol product, 150 parts by mass of brominated bisphenol A type epoxy resin (Nippon Kayaku Co., Ltd., product number "EPPN501H"), 55 parts by mass of phenol novolac type epoxy resin (Asahi Ciba Co., Ltd., product number “EPN1182”) and 1 part by weight of diaminodiphenylmethane (Japan Epo Shirejin Co., is obtained by blending the product name "Ethacure"), and a curing accelerator 1 part by weight of 2-ethyl-4-methylimidazole (manufactured by Shikoku Chemicals Corporation).
[0047]
The details of the spherical silica in the table are as follows.
-Spherical silica (average particle size: 0.5 μm): Synthetic silica having an approximately spherical particle size (manufactured by Admatechs, product number "SO-C2")
-Spherical silica (average particle size: 1.0 µm): Synthetic silica having a substantially spherical particle size (manufactured by Admatechs Co., Ltd., product number "SO-C3")
・ Spherical silica (average particle size: 2.0 μm): synthetic silica having a substantially spherical particle size, manufactured by Admatechs Co., Ltd., product number “SO-C5”)
・ Spherical silica (average particle size 5.0 μm): Synthetic silica with a substantially spherical particle size (Tatsumori, product number “Fuselex WX”)
(Evaluation test)
With respect to the double-sided copper-clad laminate obtained in each of the above Examples and Comparative Examples, each evaluation test of formability, drill wear rate, and inner wall roughness was performed.
[0048]
The moldability was evaluated by removing the copper foil on the surface of the obtained double-sided copper-clad laminate by etching, observing the presence of burrs on the surface and the presence of voids in the cross-section, and marking も のOr, those having voids were judged as "x".
[0049]
Heat resistance is obtained by cutting the obtained double-sided copper-clad laminate to a size of 50 mm x 50 mm and placing it in an oven at 250 ° C to 280 ° C for 1 hour at 5 ° C intervals, and the maximum temperature at which no blistering occurs Was evaluated as an oven heat-resistant temperature.
[0050]
Regarding the drill wear rate, 2,000 holes were drilled on the obtained double-sided copper-clad laminate using a union tool super-steel drill bit having a diameter of 0.1 mm. Then, photographs of the cutting edge of the drill bit before and after the processing were taken to observe the wear amount of the cutting edge, and the area reduction rate of the cutting edge was evaluated as the wear rate.
[0051]
The inner wall roughness was determined by performing desmearing with permanganic acid on the inner surface of the hole of the drilled double-sided copper-clad laminate, and then plating the inner wall of the hole with a 20 μm thick copper plate. Was observed with a microscope, and evaluated by the maximum value of the difference between the irregularities on the inner wall.
[0052]
Table 1 shows the above results. In the case where the evaluation result of the oven heat-resistant temperature was “-”, the laminate having poor moldability was heated, and blisters had already occurred at the measurement start temperature of 260 ° C. In addition, the evaluation result of the inner wall roughness is “−”, because cracks and the like are generated as a result of drilling a laminate having poor formability, and the inner wall roughness is reduced. Shows what has grown beyond the measurement range.
[0053]
[Table 1]

[0054]
As is clear from the results in Table 1, Examples 1 to 6 have good moldability, high heat resistance, low drill wear rate, no breakage, and low hole inner wall roughness. Met.
[0055]
【The invention's effect】
As described above, the prepreg according to claim 1 has an air permeability of 2 to 4 cm. ³ / Cm ² / Sec, a glass cloth containing 240 parts by mass or less of an inorganic filler based on 100 parts by mass of the total amount of the resin component, and having an average particle size of 0.2 to 3.0 μm. Since the thermosetting resin composition is impregnated with the curable resin composition to be in a B-stage state, when a laminate is manufactured using such a prepreg, the strength of the laminate is uniformed, and the formation of through holes is performed. Even when small diameter drilling is performed, excessive load is not applied to the drill and drill breakage can be suppressed, and the life of the drill can be extended, and it is formed by drilling. The inner wall of the hole can be formed smoothly, and even if the hole density increases and the distance between the walls of the through-holes becomes short, a hole such as a CAF (Conductive Anodic Filaments) is used. It is possible to suppress the occurrence of migration. In addition, by impregnating a resin varnish containing an inorganic filler, it is possible to impart high heat resistance and rigidity to the laminate, and to ensure good impregnation of the resin varnish with the base material, thereby facilitating the production of the laminate. It is also possible to suppress the occurrence of molding defects such as voids and voids.
[0056]
Further, in the invention of claim 2, since silica having a substantially spherical particle shape is used as the inorganic filler, the dielectric constant of the laminate formed by the prepreg is reduced and the water absorption of the laminate is reduced. It can suppress the deterioration of the performance and improve the fluidity of the composition at the time of prepreg molding, and can further suppress the occurrence of abrasion and breakage of the working drill at the time of drilling. is there.
[0057]
Further, the laminated plate according to the third aspect is formed by laminating and integrating the required number of prepregs according to the first or second aspect and a metal foil, so that the strength is made uniform and a small diameter drilling process is performed to form a through hole. Even in this case, excessive load is not applied to the drill and drill breakage can be suppressed, and the life of the drill can be extended, and the inner wall of the hole formed by drilling is smoothed. Thus, even if the hole density increases and the distance between the walls of the through holes becomes short, the occurrence of migration such as CAF can be suppressed. It is also possible to suppress the occurrence of molding defects such as frays and voids in the production of the laminate, and to impart high heat resistance to the laminate.

Claims (3)

By applying at least one of a flattening process and a fiber opening process to the glass cloth, the base material having an air permeability of 2 to 4 cm ³ / cm ² / sec, based on 100 parts by mass of the total amount of the resin component A thermosetting resin composition containing 240 parts by mass or less of an inorganic filler and having an average particle size of 0.2 to 3.0 μm is impregnated with the thermosetting resin composition. A prepreg characterized by being in a stage state. The prepreg according to claim 1, wherein silica having a substantially spherical particle shape is used as the inorganic filler. A laminate comprising a required number of prepregs according to claim 1 and a metal foil laminated and integrated.