JP6686540B2 - Printed wiring board - Google Patents

Description

  The present invention relates to a printed wiring board. In particular, the present invention relates to a printed wiring board with reduced variation in signal transmission delay time.

  In recent years, the speeding up and increasing the capacity of data communication used in information communication have been rapidly advanced. Therefore, in the above electronic device, a printed wiring board that has both high frequency characteristics and multilayer wiring is required.

  A printed wiring board used for information communication is required to have a low dielectric constant (low Dk) and a low dielectric loss tangent (low Df) in order to reduce the signal propagation delay and the transmission loss. In order to meet these requirements, a resin material containing polyphenylene ether is used as an insulating layer between wirings that are multilayered in a printed wiring board. Polyphenylene ether is a compound that has excellent electrical properties (low dielectric constant and low dielectric loss tangent) and is expected to be effective in increasing transmission speed and reducing transmission loss. In order to improve the performance and increase the number of layers of a printed wiring board, attempts have been made to apply the prepreg laminate using the polyphenylene ether to the printed wiring board.

  Further, as the performance and the number of layers of the printed wiring board are increased, the material for the printed wiring board used for the printed wiring board is required to be thin and have high rigidity. In order to meet these requirements, for example, in Patent Document 1 and Patent Document 2, a prepreg using glass cloth as a base material is used.

JP 2002-194212 A JP, 10-273518, A

  By the way, in the wiring arranged between the layers of the prepreg of the printed wiring board, the signal transmission delay time varies within the plane due to the relationship between the density of the glass fibers forming the glass cloth and the position of the wiring.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a printed wiring board in which variation in signal transmission delay time is reduced in wiring arranged between layers of a prepreg of the printed wiring board. To do.

  In the printed wiring board according to the embodiment of the present invention, the insulating layer between at least one pair of adjacent wirings is composed of a plurality of prepregs.

  Further, in the printed wiring board, the fiber base material included in the prepreg may have a dielectric constant of 7.0 or less.

The resin composition contained in the prepreg contains a polyphenylene ether cross-linking type curing material, and the polyphenylene ether has a number average molecular weight of 1,000 to 7,000 and may be represented by the following formula (I).
Here, in the formula, X represents an aryl group, (Y) _m represents a polyphenylene ether moiety, and R ^{1 to} R ³ independently represent a hydrogen atom, an alkyl group, an alkenyl group, or an alkynyl group. n shows the integer of 1-6, q shows the integer of 1-4.

  Further, the resin composition contained in the prepreg is an epoxy compound having a number average molecular weight of 1000 or less, a halogen atom having at least two epoxy groups in one molecule, a polyphenylene ether having a number average molecular weight of 5000 or less, and a cyanate ester. A resin varnish containing a halogen-based flame retardant and a curing catalyst that accelerates the reaction of the compound, the epoxy compound, and the polyphenylene ether with the cyanate ester compound that is the curing agent may be included.

  Further, the wiring may include a metal selected from copper, gold, silver and alloys thereof.

  According to the present invention, it is possible to provide a printed wiring board in which variation in signal transmission delay time is reduced in wiring arranged between layers of a prepreg of the printed wiring board.

1 shows a cross-sectional view of a printed wiring board 100 according to an embodiment of the present invention. It is a table | surface which shows the structure and evaluation result of the prepreg based on one Example of this invention. It is a table | surface which shows the structure and evaluation result of the prepreg based on one Example of this invention. A sectional view of a conventional printed wiring board 900 is shown.

  FIG. 4 shows a cross-sectional view of a conventional printed wiring board 900. The printed wiring board 900 includes, for example, wiring (950, 951, 953) and an insulating layer (prepreg) 910. The insulating layer 910 is composed of the resin composition 920 and the glass fiber base material 930.

In the printed wiring board 900, the wiring 951 and the wiring 953 have different signal transmission delay times. This is because the signal transmission delay time has the following relationship.
Signal propagation delay time (T) ∝√Dk / C
Here, Dk represents the dielectric constant of the material, and C represents the speed of light.

  In FIG. 4, the region A around the wiring 951 is mainly occupied by the resin composition 920 and has a low dielectric constant. On the other hand, the region B around the wiring 953 is mainly occupied by the glass fiber base material 930 and has a high dielectric constant. Therefore, the signal transmission delay time of the wiring 951 is shorter than the signal transmission delay time of the wiring 953. As a result, in-plane variations occur in the signal transmission delay time.

<Embodiment 1>
Hereinafter, the printed wiring board according to the present invention will be described in detail. However, the printed wiring board of the present invention should not be construed as being limited to the description of the embodiments and examples below.

[Configuration of printed wiring board]
FIG. 1 shows a cross-sectional view of a printed wiring board 100 according to an embodiment of the present invention. In the printed wiring board 100, the insulating layer between at least one pair of adjacent wirings 151 and 153 is composed of a plurality of prepregs 110. In FIG. 1, as an example, the prepreg 110 includes the insulating layers 111 and 113 formed of two layers, but the number of layers of the prepreg 110 forming the insulating layers 111 and 113 between the wiring 151 and the wiring 153 is appropriately set. It can be set.

  The inventors of the present invention form a multilayered prepreg 110 in the insulating layers 111 and 113 between at least one pair of the wiring 151 and the wiring 153 that are adjacent to each other, so that the resin composition 120 is provided around the wiring 151 and the wiring 153. It was found that the distribution with the glass fiber base material 130 can be made uniform, and as a result, the variation in the signal transmission delay time within the plane can be reduced.

  In one embodiment, the fiber base material 130 included in the prepreg 110 forming the printed wiring board 100 is a fiber base material having a dielectric constant of 7.0 or less. By using the fiber base material having a dielectric constant of 7.0 or less, it is possible to reduce the variation in the signal transmission delay time within the plane. Further, in the printed wiring board 100 according to the present invention, by making the prepreg 110 including the fiber base material having a dielectric constant of 7.0 or less into multiple layers, it is possible to further reduce the variation in the signal transmission delay time within the plane. .

[Structure of prepreg]
The prepreg according to Embodiment 1 of the present invention includes a resin composition having a low dielectric constant (Dk) and a dielectric loss tangent (Df), for example, a polyphenylene ether resin composition, and a polyphenylene ether cross-linking type curing agent. .

(Polyphenylene ether)
The polyphenylene ether contained in the resin composition used for the prepreg according to Embodiment 1 of the present invention is represented by the following general formula (1), and a polyphenylene ether having a number average molecular weight of 1,000 or more and 7,000 or less can be used.

In the above general formula (1), X represents an aryl group, (Y) _m represents a polyphenylene ether moiety, and R ^{1 to} R ³ each independently represent a hydrogen atom, an alkyl group, an alkenyl group or an alkynyl group. . In the general formula (1), n is an integer of 1 or more and 6 or less, and q is an integer of 1 or more and 4 or less. Here, preferably, n is an integer of 1 or more and 4 or less, more preferably n is 1 or 2, and ideally n is 1. In addition, q is preferably an integer of 1 or more and 3 or less, more preferably q is 1 or 2, and ideally q is 1.

(Aryl group)
An aromatic hydrocarbon group can be used as the aryl group in the general formula (1). Specifically, a phenyl group, a biphenyl group, an indenyl group, and a naphthyl group can be used as the aryl group, and the aryl group is preferably used. Here, the aryl group includes a diphenyl ether group or the like in which the above aryl group is bonded to an oxygen atom, a benzophenone group or the like bonded to a carbonyl group, or a 2,2-diphenylpropane group or the like bonded to an alkylene group. But it's okay. The aryl group may be substituted with a general substituent such as an alkyl group (preferably a C ₁ -C ₆ alkyl group, especially a methyl group), an alkenyl group, an alkynyl group or a halogen atom. However, since the “aryl group” is substituted on the polyphenylene ether moiety via an oxygen atom, the limit of the number of general substituents depends on the number of polyphenylene ether moieties.

(Polyphenylene ether part)
The polyphenylene ether moiety in the general formula (1) is represented by the following general formula (2) and is composed of a phenyloxy repeating unit. Here, the phenyl group may be substituted with a general substituent.

In the above general formula (2), R ^{4 to} R ⁷ each represent a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group or an alkenylcarbonyl group. In General formula (2), m shows the integer of 1-100. Here, the value of m is adjusted so that the polyphenylene ether of the general formula (1) has a number average molecular weight of 1,000 or more and 7,000 or less. That is, m is not a fixed value but may be a variable within a certain range such that the number average molecular weight of the entire polyphenylene ether contained in the polyphenylene ether resin composition is 1,000 or more and 7,000 or less.

  Here, if the number average molecular weight of the polyphenylene ether exceeds 7,000, the fluidity at the time of molding is lowered and it becomes difficult to perform multilayer molding. On the other hand, when the number average molecular weight of the polyphenylene ether is less than 1000, the original excellent dielectric properties and heat resistance of the polyphenylene ether resin may not be obtained. In order to obtain more excellent fluidity, heat resistance, and dielectric properties, the polyphenylene ether preferably has a number average molecular weight of 1200 or more and 5000 or less. More preferably, the number average molecular weight of the polyphenylene ether is 1500 or more and 4500 or less.

  Further, the polyphenylene ether having the above number average molecular weight has very good compatibility when blended with a crosslinking type curing agent. In other words, the smaller the number average molecular weight of the polyphenylene ether, the higher the compatibility with the mixture. Therefore, the viscosity increase due to phase separation is unlikely to occur, and the volatilization of the cross-linking curing agent having a low molecular weight is suppressed. As a result, the embedding property of the polyphenylene ether resin composition in a via hole or the like can be improved.

  As the alkyl group, the alkenyl group, and the alkynyl group in the general formula (2), the same ones as the alkyl group, the alkenyl group, and the alkynyl group in the general formula (1) described below can be used. As the alkenylcarbonyl group of the polyphenylene ether moiety, the carbonyl group substituted with the above alkenyl group can be used. Specifically, an acryloyl group or a methacryloyl group can be used.

Here, the polyphenylene ether moiety in the general formula (2) includes, as the substituents R ^{4 to} R ⁷ , vinyl group, 2-propylene group (allyl group), methacryloyl group, acryloyl group, 2-propyne group (propargyl group), and the like. It may have an unsaturated hydrocarbon-containing group. When the substituents R ^{4 to} R ⁷ of the polyphenylene ether moiety are provided with the above unsaturated hydrocarbon-containing group, a more remarkable effect of the crosslinkable curing agent can be obtained.

  The polyphenylene ether having the above group at the terminal has good interaction with the cross-linking type curing agent. Therefore, the heat resistance can be improved by adding a relatively small amount of the cross-linking type curing agent, and the low dielectric constant can be realized.

(Alkyl group)
As the alkyl group in the general formulas (1) and (2), a saturated hydrocarbon group can be used. As the above alkyl group, a C ₁ -C ₁₀ alkyl group may be used. Preferably, it is the use of C ₁ -C ₆ alkyl group as the alkyl group described above. More preferably, it may be used a C ₁ -C ₄ alkyl group as the alkyl group described above. More preferably, a C ₁ -C ₂ alkyl group may be used as the above alkyl group. Specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, or a hexyl group can be used as the alkyl group.

(Alkenyl group)
As the alkenyl group in the general formulas (1) and (2), an unsaturated hydrocarbon group having at least one carbon-carbon double bond in the structure can be used. The alkenyl groups described above may be performed using C ₂ -C ₁₀ alkenyl group. Preferably, it is the use of C ₂ -C ₆ alkenyl group as an alkenyl group described above. More preferably, it is the use of C ₂ -C ₄ alkenyl group as an alkenyl group described above. Specifically, an ethylene group, a 1-propylene group, a 2-propylene group, an isopropylene group, a butylene group, an isobutylene group, a pentylene group, or a hexylene group can be used as the alkenyl group.

(Alkynyl group)
As the alkynyl group in the general formulas (1) and (2), an unsaturated hydrocarbon group having at least one carbon-carbon triple bond in the structure can be used. The alkynyl groups described above may be performed using C ₂ -C ₁₀ alkynyl group. Preferably, it is the use of C ₂ -C ₆ alkynyl group as an alkynyl group as described above. More preferably, it is the use of C ₂ -C ₄ alkynyl group as an alkynyl group as described above. Specifically, an ethyne group, a 1-propyne group, a 2-propyne group, an isopropyne group, a butyne group, an isobutyne group, a pentin group, and a hexyne group can be used as the alkynyl group.

(Crosslinking type curing agent)
As the cross-linking type curing agent contained in the present resin composition, a curing agent that three-dimensionally cross-links polyphenylene ether can be used. Specifically, a polyfunctional vinyl compound, a vinylbenzyl ether compound, an allyl ether compound, or a trialkenyl isocyanurate can be used as the cross-linking curing agent. The polyfunctional vinyl compound includes divinylbenzene, divinylnaphthalene and divinylbiphenyl. The vinyl benzyl ether compound is synthesized by the reaction of phenol and vinyl benzyl chloride. Allyl ether compounds are synthesized by the reaction of styrene monomer, phenol, and allyl chloride. Trialkenyl isocyanurate has good compatibility, and triallyl isocyanurate (hereinafter, TAIC) or triallyl cyanurate (hereinafter, TAC) can be used.

  In addition to the above materials, (meth) acrylate compounds (methacrylate compounds and acrylate compounds) can be used as the cross-linking curing agent. In particular, the functional (meth) acrylate compound having a functional number of 3 or more and 5 or less is preferably contained in an amount of 3% by mass or more and 20% by mass or less based on the total amount of the resin composition. Trimethylolpropane trimethacrylate (TMPT) or the like can be used as the methacrylate compound having a function of 3 or more and 5 or less, while trimethylolpropane triacrylate or the like can be used as a acrylate compound having a function of 3 or more and 5 or less. You can By using the above-mentioned crosslinking type curing agent, the heat resistance of the resin composition can be further improved.

  When the functionality of the (meth) acrylate compound is less than 3 or more than 5, the heat resistance is lower than that of the (meth) acrylate compound having a functionality of 3 or more and 5 or less. Even if the (meth) acrylate compound has a functionality of 3 or more and 5 or less, if the content is less than 3% by mass relative to the total amount of the resin composition, the effect of improving the heat resistance of the resin composition is sufficient. Can't get to. On the other hand, if it exceeds 20% by mass, the dielectric properties and moisture resistance will deteriorate.

  The content ratio of the polyphenylene ether and the cross-linking type curing agent in the resin composition is preferably 30/70 or more and 90/10 or less. Preferably, the above content ratio is 50/50 or more and 90/10 or less. More preferably, the content ratio is 60/40 or more and 90/10 or less.

  Here, if the content ratio of the polyphenylene ether is less than the lower limit, the rigidity of the entire resin composition will be low. Due to the influence, it becomes difficult to form a multilayer of the entire resin composition. On the other hand, when the content ratio of the polyphenylene ether is higher than the upper limit, the heat resistance of the entire resin composition is reduced. By adjusting the content ratio of the polyphenylene ether and the crosslinking type curing agent within the above range, good fluidity and compatibility of the resin composition can be obtained. Therefore, the embeddability of the resin composition into the via hole or the like can be improved.

  In the prepreg of the present invention, the volume content based on the specific gravity of the resin composition is preferably 45% by volume or more and 90% by volume or less.

(Fiber substrate)
As the fiber base material included in the prepreg used for the printed wiring board 100 according to the embodiment of the present invention, it is preferable to use a glass fiber base material having a dielectric constant of 7.0 or less. As the glass having such a low dielectric constant, cloth such as E glass, D glass, S glass, T glass, NE glass, and quartz can be used. Further, the thickness of the glass cloth is not particularly limited, but it is used for laminated plate applications in the range of 0.01 to 0.2 mm, and in particular, the glass woven fabric subjected to the super-opening treatment or the filling treatment has a dimension It is preferable in terms of stability. Further, a glass cloth surface-treated with a silane coupling agent such as an epoxysilane treatment or an aminosilane treatment is preferably used from the viewpoint of heat resistance against moisture absorption. Further, as the fiber base material, an organic fiber base material having a dielectric constant of 7.0 or less can also be used. Examples of such an organic fiber base material include a liquid crystal polyester fiber base material and an aramid fiber base material.

  In the prepreg according to the present invention, the volume content based on the specific gravity of the glass fiber base material is preferably 5% by volume or more and 30% by volume or less. The prepreg of the present invention, by setting the volume content based on the specific gravity of the glass fiber base material in these ranges, increases the volume content based on the specific gravity of the resin composition with respect to the prepreg, and the dielectric constant of the entire prepreg ( Dk) and dielectric loss tangent (Df) can be reduced.

(Inorganic filler)
The inorganic filler contained in the prepreg used in the printed wiring board 100 according to the present invention can include, for example, silica, but is not limited thereto. As the silica, for example, spherical synthetic silica can be used, and fine particles having an average particle size of 10 μm or less can be used. The average particle size here may be a value described in a material such as a catalog of fillers to be added, or may be an average value or a median value of a plurality of randomly extracted fillers. By setting the average particle diameter of the filler to the above condition, a prepreg having high smoothness and reliability can be obtained. In the prepreg of the present invention, by adding silica to the prepreg, it is possible to effectively suppress an increase in the thermal expansion coefficient of the prepreg.

(Other additives)
The resin composition may contain one or more additives selected from unmodified polyphenylene ether, a flame retardant, and a reaction initiator, if necessary. Further, a general additive component of a resin composition used for manufacturing an electronic device such as a printed wiring board may be added.

(Unmodified polyphenylene ether)
In addition to the above polyphenylene ether, the resin composition may contain unmodified polyphenylene ether having a number average molecular weight of 9,000 or more and 18,000 or less. By adding unmodified polyphenylene ether, it is possible to realize control of fluidity and improvement of heat resistance of the resin composition. Further, in the resin composition, it is possible to suppress precipitation of an additive component such as a filler. Here, the unmodified polyphenylene ether is a polyphenylene ether having no carbon-carbon unsaturated group in the molecule, and the addition amount thereof is 100 parts by mass of the total mass of the polyphenylene ether and the crosslinking type curing agent. However, it is preferably 3 parts by mass or more and 70 parts by mass or less.

  Further, in order to improve heat resistance, adhesion and dimensional stability, styrene / butadiene block copolymer, styrene / isoprene block copolymer, 1,2-polybutadiene, 1,4-polybutadiene, maleic acid modified polybutadiene, acrylic acid modified polybutadiene , And one or more compatibilizers selected from epoxy-modified polybutadiene can be used.

(Flame retardants)
By adding a flame retardant to the present resin composition, the water resistance, moisture resistance, moisture absorption heat resistance, and glass transition point of the prepreg using the present resin composition can be improved. As the flame retardant, a brominated organic compound such as an aromatic bromine compound can be used. Specifically, decabromodiphenylethane, 4,4-dibromobiphenyl, ethylenebistetrabromophthalimide, or the like can be used. Preferably, the brominated organic compound is contained in an amount such that the content of bromine is 8% by mass or more and 20% by mass or less based on the total amount of the resin composition.

  When the content of bromine is less than the lower limit, the flame retardancy of the prepreg is lowered and it becomes impossible to maintain the flame retardancy of UL standard 94V-0 level. On the other hand, when the content of bromine is larger than the upper limit, bromine is likely to dissociate during heating of the prepreg and the heat resistance of the prepreg deteriorates.

(Reaction initiator)
By adding a reaction initiator to the present resin composition, a more remarkable effect of the cross-linking type curing agent can be obtained. As the reaction initiator, a general material can be used as long as it can improve the properties such as heat resistance of the resin composition by promoting the curing of the resin composition at an appropriate temperature and time. Specifically, α, α′-bis (t-butylperoxy-m-isopropyl) benzene, 2,5-dimethyl-2,5-di (t-butylperoxy) -3-hexyne, benzoyl peroxide , 3,3 ′, 5,5′-tetramethyl-1,4-diphenoquinone, chloranil, 2,4,6-tri-t-butylphenoxyl, t-butylperoxyisopropyl monocarbonate, azobisisobutyronitrile Oxidizing agents such as Here, if desired, a carboxylic acid metal salt or the like may be added to further accelerate the curing reaction.

  In the printed wiring board 100 according to the present invention, the prepreg 110 is multilayered in the insulating layers 111 and 113 between at least one pair of the adjacent wiring 151 and the wiring 153, so that the wiring 151 and the wiring 153 are surrounded. By making the distribution of the resin composition 120 and the fiber base material 130 uniform, it is possible to reduce the variation in the signal transmission delay time within the plane.

[Prepreg manufacturing method]
A method for producing the prepreg according to the first embodiment of the present invention will be described. First, polyphenylene ether, a cross-linking curing agent, and additives are mixed with an organic solvent to form a varnish. The organic solvent is not particularly limited as long as it does not dissolve the brominated organic compound but the resin component and does not adversely affect the reaction. For example, ketones such as methyl ethyl ketone, ethers such as dibutyl ether, esters such as ethyl acetate, amides such as dimethylformamide, aromatic hydrocarbons such as benzene, toluene and xylene, chlorinated hydrocarbons such as trichloroethylene, etc. One of these suitable organic solvents or a mixture of two or more thereof is used. The concentration of the resin solid content of the varnish may be appropriately adjusted according to the operation of impregnating the base material with the varnish, and can be, for example, 40% by mass or more and 90% by mass or less.

  A prepreg can be obtained by impregnating a base material with the above-mentioned varnish and further heating and drying to remove the organic solvent and semi-curing the resin in the base material. In the prepreg according to the present invention, glass cloth can be used as the base material. In one embodiment, it is preferable to use a fiber base material having a dielectric constant of 7.0 or less.

  The amount of the varnish impregnated into the base material is preferably such that the mass ratio of the resin solid content in the prepreg is 35 mass% or more. Since the dielectric constant of the base material is higher than that of the resin, in order to reduce the dielectric constant of the printed wiring board obtained using this prepreg, the content of the resin solid content in the prepreg should be less than the above mass ratio. It should be a lot. The base material impregnated with the varnish can be heated at a temperature of 80 ° C. or higher and 180 ° C. or lower for a period of 1 minute to 10 minutes.

[Method for manufacturing printed wiring board]
Here, a method of manufacturing the printed wiring board 100 using the prepreg manufactured as described above will be described. First, one or a plurality of prepregs are stacked, and metal foil such as copper foil is stacked on both upper and lower surfaces or one surface of the prepreg, and the laminated body is heated and pressed. By this molding, a laminate having a metal foil on both sides or one side can be produced. A printed wiring board is obtained by patterning and etching the metal foil of this laminate to form a circuit. Then, the printed wiring board 100 can be produced by stacking a plurality of prepregs with the printed wiring board on which the circuit is formed sandwiched therebetween and performing heat press molding.

The heating and pressurizing condition varies depending on the content ratio of the raw material of the resin composition used, but is generally 170 ° C or higher and 230 ° C or lower, and the pressure is 1.0 MPa or higher and 6.0 MPa or lower (10 kg / cm ² or more and 60 kg / cm ² It is preferable to heat and pressurize under the following conditions for an appropriate time.

  The metal foil used for the printed wiring board according to the present invention has a surface roughness (ten-point average roughness: Rz) of 2 μm or less, and the surface on the side where the resin layer is formed by the prepreg (the side in contact with the prepreg). (The surface of) is treated with zinc or a zinc alloy for the purpose of preventing rust and improving the adhesion to the resin layer, and a copper foil subjected to a coupling treatment with a vinyl group-containing silane coupling agent or the like can be used. . Such a copper foil has good adhesion to the resin layer (insulating layer), and a printed wiring board having excellent high frequency characteristics can be obtained. When the copper foil is treated with zinc or a zinc alloy, zinc or a zinc alloy can be formed on the surface of the copper foil by a plating method. In addition to copper, a metal selected from gold, silver, and alloys thereof can be used as the metal forming the wiring.

  A through hole is formed by drilling in the stacking direction of the printed wiring boards thus formed. Metal plating is performed to fill the through holes with metal to form through holes.

  The printed wiring board thus obtained can reduce variations in signal transmission delay time. Furthermore, it is possible to obtain a printed wiring board having excellent moldability, water resistance, moisture resistance, and heat resistance after moisture absorption, and having a high glass transition point.

<Embodiment 2>
Hereinafter, the printed wiring board according to the present invention will be described in detail. However, the printed wiring board of the present invention should not be construed as being limited to the description of the embodiments and examples below.

[Configuration of printed wiring board]
The basic configuration of the printed wiring board according to the second embodiment is the same as that of the first embodiment. In the second embodiment, in the printed wiring board 100, the insulating layer between at least one pair of adjacent wirings 151 and 153 is composed of a plurality of prepregs 110. By multi-layering the prepreg 110, the distribution of the resin composition 120 and the fiber base material 130 around the wiring 151 and the wiring 153 can be made uniform, and as a result, in the plane of the signal transmission delay time. Variation can be reduced.

  Further, in one embodiment, the fiber base material 130 included in the prepreg 110 that constitutes the printed wiring board 100 is a fiber base material having a dielectric constant of 7.0 or less. By using the fiber base material having a dielectric constant of 7.0 or less, it is possible to reduce the variation in the signal transmission delay time within the plane.

[Structure of prepreg]
The prepreg according to Embodiment 2 of the present invention contains an epoxy compound, a polyphenylene ether, a cyanate ester compound, a curing catalyst, and a halogen-based flame retardant. The epoxy compound has a number average molecular weight of 1,000 or less and does not contain a halogen atom having at least two epoxy groups in one molecule. Further, the polyphenylene ether has a number average molecular weight of 5000 or less. Further, the curing catalyst promotes the reaction between the epoxy compound and polyphenylene ether and the cyanate ester compound which is the curing agent.

(Epoxy compound)
As the epoxy compound, a dicyclopentadiene type epoxy compound, a bisphenol A type epoxy compound, a bisphenol F type epoxy compound, a phenol novolac type epoxy compound, a naphthalene type epoxy compound, a biphenyl type epoxy compound or the like can be used. These may be used alone or in combination of two or more. Of the above, the dicyclopentadiene type epoxy compound, the bisphenol A type epoxy compound, the bisphenol F type epoxy compound, and the biphenyl type epoxy compound are particularly preferable because they have good compatibility with the polyphenylene ether. It is preferable that the present resin composition does not contain a halogenated epoxy compound, but it may be added if necessary as long as it does not impair the effects of the present invention.

  The content of the epoxy compound in the prepreg of the present embodiment is preferably 20% by mass or more and 60% by mass or less based on 100 parts by mass of the total amount of the components of the epoxy compound, the polyphenylene ether, and the cyanate ester compound. More preferably, the content ratio of the epoxy compound is 30% by mass or more and 50% by mass or less. By setting the content of the epoxy compound in the above range, it is possible to maintain sufficient heat resistance and excellent mechanical properties and electrical properties.

(Polyphenylene ether)
The polyphenylene ether has a number average molecular weight of 5000 or less, preferably 2000 or more and 4000 or less.

  If the number average molecular weight of the polyphenylene ether exceeds 5,000, the fluidity becomes poor and the reactivity with the epoxy group also becomes low. Therefore, the curing reaction takes a long time, the unreacted substances increase without being taken into the curing system, the glass transition temperature decreases, and sufficient heat resistance cannot be obtained.

  The content ratio of the polyphenylene ether in the prepreg of the present embodiment is preferably 20% by mass or more and 60% by mass or less based on 100 parts by mass of the total amount of the components of the epoxy compound, the polyphenylene ether, and the cyanate ester compound. More preferably, the content ratio of polyphenylene ether is 20% by mass or more and 40% by mass or less. When the content ratio of the polyphenylene ether is within the above range, excellent dielectric properties can be obtained.

(Cyanate ester compound)
As the cyanate ester compound, a compound having two or more cyanate groups in one molecule can be used. Specifically, 2,2-bis (4-cyanatophenyl) propane, bis (3,5-dimethyl-4-cyanatophenyl) methane, 2,2-bis (4-cyanatophenyl) ethane, etc. Alternatively, aromatic cyanate ester compounds such as derivatives thereof can be used. These may be used alone or in combination of two or more.

  The cyanate ester compound is a component that acts as a curing agent for the epoxy compound to form an epoxy resin and forms a rigid skeleton. Therefore, a high glass transition point (Tg) can be obtained. In addition, since the viscosity is low, it is possible to maintain high fluidity of the obtained resin varnish.

  The content ratio of the cyanate ester compound in the prepreg of the present embodiment is 20% by mass or more and 60% by mass or less based on 100 parts by mass of the total amount of the components of the epoxy compound, the polyphenylene ether, and the cyanate ester compound. preferable. More preferably, the content ratio of the cyanate ester compound is 20% by mass or more and 40% by mass or less. When the content ratio of the cyanate ester compound is within the above range, sufficient heat resistance can be obtained, the impregnation property with respect to the substrate is excellent, and it is possible to prevent crystals from precipitating in the resin varnish.

(Curing catalyst)
Examples of the curing catalyst include organic acid salts of organic acids such as octanoic acid, stearic acid, acetylacetonate, naphthenic acid and salicylic acid such as Zn, Cu and Fe, tertiary amines such as triethylamine and triethanolamine, 2-ethyl- Imidazoles such as 4-imidazole and 4-methylimidazole can be used. These may be used alone or in combination of two or more. Among the above, an organic metal salt, particularly zinc octanoate, is preferable because higher heat resistance can be obtained.

  The content ratio of the curing catalyst in the prepreg of the present embodiment is 0.005 parts by mass with respect to 100 parts by mass of the total amount of the components of the epoxy compound, the polyphenylene ether, and the cyanate ester compound when an organic metal salt is used, for example. The amount can be 5 parts by mass or more and 5 parts by mass or less. When using imidazoles, for example, the content ratio of the curing catalyst is 0.01 parts by mass or more and 5 parts by mass or less based on 100 parts by mass of the total amount of the components of the epoxy compound, polyphenylene ether, and cyanate ester compound. can do.

  In the prepreg of the present invention, the volume content based on the specific gravity of the resin composition is preferably 45% by volume or more and 90% by volume or less.

(Halogen flame retardant)
As the halogen-based flame retardant, a halogen-based flame retardant that does not dissolve in a varnish prepared with a solvent such as toluene can be used. Specifically, as the halogen-based flame retardant, ethylenedipentabromobenzene, ethylenebistetrabromophthalimide, decabromodiphenyloxide, tetradecabromodiphenoxybenzene, bis (tribromophenoxy) ethane or the like can be used. Among them, ethylenedipentabromobenzene, ethylenebistetrabromophthalimide, decabromodiphenyloxide, and tetradecabromodiphenoxybenzene have a high melting point of 300 ° C. or higher, and therefore have high heat resistance, so that the heat resistance of the prepreg should be improved. You can When a halogen-based flame retardant having a high melting point of 300 ° C. or higher is used, it is possible to suppress the elimination of halogen at high temperatures, and thus it is possible to suppress the decrease in heat resistance due to the decomposition of the cured product.

  The average particle size of the halogen-based flame retardant in a dispersed state is 0.1 μm or more and 50 μm or less, and more preferably 1 μm or more and 10 μm or less, so that heat resistance and interlayer insulating properties can be sufficiently maintained. The average particle diameter can be measured with a particle size distribution meter (SALD-2100) manufactured by Shimadzu Corporation.

  The content ratio of the halogen-based flame retardant in the prepreg of the present embodiment is such that the halogen concentration is 5% by mass or more and 30% by mass or less in the total amount of the resin component (that is, the component excluding the inorganic component) in the obtained cured product. It is preferable to contain them in various proportions.

(Fiber substrate)
As the fiber base material included in the prepreg used for the printed wiring board 100 according to the embodiment of the present invention, it is preferable to use a glass fiber base material having a dielectric constant of 7.0 or less. As the glass having such a low dielectric constant, cloth such as E glass, D glass, S glass, T glass, NE glass, and quartz can be used. Further, the thickness of the glass cloth is not particularly limited, but it is used for laminated plate applications in the range of 0.01 to 0.2 mm, and in particular, the glass woven fabric subjected to the super-opening treatment or the filling treatment has a dimension It is preferable in terms of stability. Further, a glass cloth surface-treated with a silane coupling agent such as an epoxysilane treatment or an aminosilane treatment is preferably used from the viewpoint of heat resistance against moisture absorption. Further, as the fiber base material, an organic fiber base material having a dielectric constant of 7.0 or less can also be used. Examples of such an organic fiber base material include a liquid crystal polyester fiber base material and an aramid fiber base material.

  In the prepreg of the present invention, the volume content based on the specific gravity of the glass fiber base material is preferably 5% by volume or more and 30% by volume or less. The prepreg of the present invention, by setting the volume content based on the specific gravity of the glass fiber base material in these ranges, increases the volume content based on the specific gravity of the resin composition with respect to the prepreg, and the dielectric constant of the entire prepreg ( Dk) and dielectric loss tangent (Df) can be reduced.

(Inorganic filler)
The inorganic filler contained in the prepreg according to the present embodiment can include, for example, silica, but is not limited thereto. As the silica, for example, spherical synthetic silica can be used, and fine particles having an average particle size of 10 μm or less can be used. The average particle size here may be a value described in a material such as a catalog of fillers to be added, or may be an average value or a median value of a plurality of randomly extracted fillers. By setting the average particle diameter of the filler to the above condition, a prepreg having high smoothness and reliability can be obtained. In the prepreg of the present invention, by adding silica to the prepreg, it is possible to effectively suppress an increase in the thermal expansion coefficient of the prepreg.

  In addition to the above-mentioned inorganic filler, the resin composition of the present invention may contain a general additive component of a resin composition used for manufacturing electronic devices such as a printed wiring board. For example, a heat stabilizer, an antistatic agent, an ultraviolet absorber, a flame retardant, a dye or pigment, a lubricant and the like may be added.

(Other additives)
The resin composition of the present invention may optionally contain one or more additives selected from unmodified polyphenylene ether and a reaction initiator. Further, a general additive component of a resin composition used for manufacturing an electronic device such as a printed wiring board may be added. Since the unmodified polyphenylene ether and the reaction initiator have been described in the first embodiment, detailed description thereof will be omitted.

In the printed wiring board 100 according to the present invention, the prepreg 110 is multilayered in the insulating layers 111 and 113 between at least one pair of the adjacent wiring 151 and the wiring 153, so that the wiring 151 and the wiring 153 are surrounded. By making the distribution of the resin composition 120 and the fiber base material 130 uniform, it is possible to reduce the variation in the signal transmission delay time within the plane.

[Prepreg manufacturing method]
In the present resin composition of the prepreg according to Embodiment 2 of the present invention, the components of the epoxy compound, polyphenylene ether, and cyanate ester compound are all dissolved in the resin varnish, and the component of the inorganic filler is It is not dissolved in the resin varnish but dispersed. Such a resin varnish is prepared, for example, as follows.

  First, a predetermined amount of an epoxy compound and a cyanate ester compound are dissolved in a resin solution of polyphenylene ether. This dissolution may be carried out at room temperature or with heating. By using a material that dissolves in a solvent such as toluene at room temperature as the epoxy compound and the cyanate ester compound, it is possible to suppress the formation of precipitates in the resin varnish.

  Here, when an inorganic filler is added as an additive, the resin varnish is prepared by dispersing the filler until it reaches a predetermined dispersion state using a ball mill, a bead mill, a planetary mixer, a roll mill, etc. after the filler is added. To be done.

  A prepreg can be obtained by impregnating a base material with the resin varnish obtained as described above in the same manufacturing method as in Embodiment 1 and drying the base material. Further, the printed wiring board can be obtained by the same manufacturing method as that of the first embodiment.

  The results of evaluating the fluctuation range of the signal propagation delay time by producing the printed wiring boards according to the first and second embodiments of the present invention will be specifically described below. Examples 1 and 2 shown below correspond to examples of the first embodiment, and examples 3 and 4 correspond to examples of the second embodiment.

  First, the polyphenylene ether used in Examples 1 and 2 will be described.

(Polyphenylene ether (1))
CuBr ₂ 3.88 g (17.4 mmol), N, N'-di-t-butylethylenediamine 0.75 g (4. 4) in a 12 liter vertical reactor equipped with a stirrer, a thermometer, an air introduction tube, and a baffle plate. 4 mmol), n-butyldimethylamine 28.04 g (277.6 mmol), and toluene 2600 g were charged and stirred at a reaction temperature of 40 ° C., which was previously dissolved in 2300 g of methanol 2,2 ′, 3,3 ′, 5,5'-hexamethyl- (1,1'-biphenol) -4,4'-diol 129.3 g (0.48 mol), 2,6-dimethylphenol 233.7 g (1.92 mol), 2,3,3 6-Trimethylphenol 64.9 g (0.48 mol), N, N'-di-t-butylethylenediamine 0.51 g (2.9 mmol), n-butyldime A mixed solution of 10.90 g (108.0 mmol) of chillamine was added dropwise over 230 minutes while bubbling a mixed gas in which nitrogen and air were mixed and adjusted to an oxygen concentration of 8% at a flow rate of 5.2 liter / min. Then, stirring was performed.

  After the dropping was completed, 1500 g of water in which 19.89 g (52.3 mmol) of tetrasodium ethylenediaminetetraacetate was dissolved was added to stop the reaction. The aqueous layer and the organic layer were separated, and the organic layer was washed with a 1N aqueous hydrochloric acid solution and then with pure water. The obtained solution was concentrated to 50 wt% with an evaporator to obtain 836.5 g of a toluene solution of a bifunctional phenylene ether oligomer body (resin “A”). The resin “A” had a number average molecular weight of 986, a weight average molecular weight of 1530 and a hydroxyl group equivalent of 471.

  To a reactor equipped with a stirrer, a thermometer, and a reflux tube, a toluene solution of resin “A” 836.5 g, vinylbenzyl chloride (trade name CMS-P; manufactured by Seimi Chemical Co., Ltd.) 162.6 g, methylene chloride 1600 g, Benzyldimethylamine (12.95 g), pure water (420 g) and 30.5 wt% NaOH aqueous solution (178.0 g) were charged, and the mixture was stirred at a reaction temperature of 40 ° C. After stirring for 24 hours, the organic layer was washed with a 1N aqueous hydrochloric acid solution and then with pure water. The obtained solution was concentrated with an evaporator and added dropwise to methanol for solidification, and the solid was recovered by filtration and vacuum dried to obtain 503.5 g of "polyphenylene ether (1)". The “polyphenylene ether (1)” had a number average molecular weight of 1187, a weight average molecular weight of 1675, and a vinyl group equivalent of 590 g / vinyl group.

(Polyphenylene ether (2))
CuBr ₂ 9.36 g (42.1 mmol), N, N′-di-t-butylethylenediamine 1.81 g (10.10 g) in a 12 liter vertically long reactor equipped with a stirrer, a thermometer, an air introduction tube, and a baffle plate. 5 mmol), n-butyldimethylamine 67.77 g (671.0 mmol), and toluene 2600 g were charged, stirred at a reaction temperature of 40 ° C., and dissolved in 2300 g of methanol in advance 2,2 ′, 3,3 ′, 5,5′-Hexamethyl- (1,1′-biphenol) -4,4′-diol 129.32 g (0.48 mol), 2,6-dimethylphenol 878.4 g (7.2 mol), N, N ′ A mixed solution of 1.22 g (7.2 mmol) of di-t-butylethylenediamine and 26.35 g (260.9 mmol) of n-butyldimethylamine, The hydrogen mixed gas with an air are mixed and adjusted to an oxygen concentration of 8% 5.2 l / min flow rate 230 minutes over while bubbling with the dropwise, the mixture was stirred.

  After the completion of dropping, 1500 g of water in which tetrasodium ethylenediaminetetraacetate (48.06 g, 126.4 mmol) was dissolved was added to stop the reaction. The aqueous layer and the organic layer were separated, and the organic layer was washed with a 1N aqueous hydrochloric acid solution and then with pure water. The obtained solution was concentrated to 50 wt% with an evaporator to obtain 1981 g of a toluene solution of a bifunctional phenylene ether oligomer body (resin “B”). The resin “B” had a number average molecular weight of 1975, a weight average molecular weight of 3514 and a hydroxyl group equivalent of 990.

  To a reactor equipped with a stirrer, a thermometer, and a reflux tube, a toluene solution of resin "B" 833.4 g, vinylbenzyl chloride (trade name CMS-P; manufactured by Seimi Chemical Co., Ltd.) 76.7 g, methylene chloride 1600 g, Benzyldimethylamine (6.2 g), pure water (199.5 g), 30.5 wt% NaOH aqueous solution (83.6 g) were charged, and the mixture was stirred at a reaction temperature of 40 ° C. After stirring for 24 hours, the organic layer was washed with a 1N aqueous hydrochloric acid solution and then with pure water. The obtained solution was concentrated with an evaporator and added dropwise to methanol for solidification. The solid was recovered by filtration and dried in vacuum to obtain 450.1 g of "polyphenylene ether (2)". The vinyl “polyphenylene ether (2)” had a number average molecular weight of 2,250, a weight average molecular weight of 3,920, and a vinyl group equivalent of 1,189 g / vinyl group.

  Next, a method of manufacturing the prepreg and the printed wiring board of Examples 1 and 2 will be described.

[Example 1]
70 parts by mass of the above polyphenylene ether (1) was prepared, 100 parts by mass of toluene was added as a solvent, mixed at 80 ° C. for 30 minutes, stirred, and completely dissolved. With respect to the polyphenylene ether solution thus obtained, 30 parts by mass of "TAIC" manufactured by Nippon Kasei Co., Ltd. as a cross-linking curing agent and ethylene bis (pentabromophenyl) (albemarl) which is a brominated organic compound as a flame retardant 20 parts by mass of "SAYTEX 8010 (trade name)" manufactured by Japan Co., Ltd. and 14 parts by mass of spherical synthetic silica ("SC2050 (trade name)" manufactured by Admatechs Co., Ltd.) as an inorganic filler were mixed. These were mixed, dispersed and dissolved in toluene which is a solvent, and diluted to a solid content of 65% to obtain a varnish of the resin composition. Since the above flame retardant is a brominated organic compound that does not react with polyphenylene ether and TAIC, the flame retardant was not dissolved in toluene but dispersed in the varnish which is the resin composition.

Next, as a base material, IPC No. Using # 1067 E glass cloth, after impregnating the above varnish, it was heated and dried at a temperature of 170 ° C. for 5 minutes, and the solvent was removed to obtain a prepreg having a resin composition of 72 mass% and a thickness of 65 μm. Obtained. Two prepregs thus obtained were stacked, and copper foil (3EC-VLP, manufactured by Mitsui Mining & Smelting Co., Ltd.) having a thickness of 35 μm was stacked on the upper and lower sides thereof. A double-sided copper-clad laminate having a thickness of 130 μm was obtained by heating and pressing under the molding conditions of a temperature of 210 ° C. and a pressure of 3.0 MPa (30 kg / cm ² ) for 150 minutes.

A structure in which a predetermined inner layer circuit is formed on one surface of the copper clad laminate obtained as described above, two prepregs obtained as described above are arranged above and below the copper clad laminate, and one copper foil is laminated as the outermost layer. At a pressure of 3.0 MPa (30 kg / cm ² ) and a temperature of 210 ° C. for 150 minutes, and press lamination molding is performed, and 12 strip lines having an impedance Z = 50 Ω are provided, and a plurality of strip lines are provided between adjacent circuit layers. A 390 μm-thick printed wiring board in which prepregs were laminated was obtained. A signal of a predetermined frequency was applied to the inner layer circuit of this printed wiring board, and the fluctuation width of the signal propagation delay time was measured. The measurement results are shown in FIG.

[Example 2]
In Example 2, 70 parts by mass of the polyphenylene ether (2) was prepared, 100 parts by mass of toluene was added as a solvent, and the mixture was mixed at 80 ° C. for 30 minutes and stirred to completely dissolve it. With respect to the polyphenylene ether solution thus obtained, 30 parts by mass of "TAIC" manufactured by Nippon Kasei Co., Ltd. as a cross-linking curing agent and ethylene bis (pentabromophenyl) (albemarl) which is a brominated organic compound as a flame retardant 20 parts by mass of "SAYTEX 8010 (trade name)" manufactured by Japan Co., Ltd. and 14 parts by mass of spherical synthetic silica ("SC2050 (trade name)" manufactured by Admatechs Co., Ltd.) as an inorganic filler were mixed. These were mixed, dispersed and dissolved in toluene which is a solvent, and diluted to a solid content of 65% to obtain a varnish of the resin composition. Since the above flame retardant is a brominated organic compound that does not react with polyphenylene ether and TAIC, the flame retardant was not dissolved in toluene but dispersed in the varnish which is the resin composition.

  Next, as a base material, IPC No. Using # 1067 E glass cloth, after impregnating the above varnish, it was heated and dried at a temperature of 170 ° C. for 5 minutes, and the solvent was removed to obtain a prepreg having a resin composition of 72 mass% and a thickness of 65 μm. Obtained. Hereinafter, a printed wiring board was prepared in the same manner as in Example 1, and the fluctuation width of the signal propagation delay time was measured. The measurement results are shown in FIG.

[Comparative Example 1]
As Comparative Example 1, the same varnish as in Example 1 was used, and IPC No. After impregnating the # 2116 E glass cloth, it was heated and dried at a temperature of 170 ° C. for 5 minutes to remove the solvent to obtain a prepreg having a resin composition of 55% by mass and a thickness of 130 μm. One piece of the obtained prepreg was used, and copper foil (3EC-VLP, manufactured by Mitsui Mining & Smelting Co., Ltd.) having a thickness of 35 μm was laminated on both surfaces thereof. The temperature was 210 ° C., the pressure was 30 kg / cm ² (30 kg / cm ² ), and heating and pressing were performed under molding conditions for 150 minutes to obtain a 130 μm-thick double-sided copper-clad laminate.

A structure in which a predetermined inner layer circuit is formed on one surface of the copper clad laminate obtained as described above, one prepreg obtained as described above is arranged above and below the copper clad laminate, and one copper foil is laminated as the outermost layer. At a pressure of 30 kg / cm ² (30 kg / cm ² ) and a temperature of 210 ° C. for 150 minutes for press lamination molding, and 12 strip lines with an impedance Z = 50Ω are provided. A printed wiring board having a thickness of 350 μm was obtained by laminating prepregs. A signal having a predetermined frequency was applied to the obtained inner layer circuit of the printed wiring board of Comparative Example 1, and the fluctuation width of the signal propagation delay time was measured. The measurement results are shown in FIG.

[Comparative Example 2]
As Comparative Example 2, the varnish obtained in Example 2 was used, and IPC No. After impregnating the # 2116 E glass cloth, it was heated and dried at a temperature of 170 ° C. for 5 minutes to remove the solvent to obtain a prepreg having a resin composition of 55% by mass and a thickness of 130 μm. Hereinafter, a printed wiring board was prepared in the same manner as in Comparative Example 1, and the fluctuation width of the signal propagation delay time was measured. The measurement results are shown in FIG.

(Evaluation result of propagation delay speed)
FIG. 2 shows the configurations and evaluation results of Examples 1 and 2 and Comparative Examples 1 and 2. As shown in FIG. 2, in the printed wiring boards of Embodiments 1 and 2, the fluctuation range of the signal propagation delay time (ps / m) was less than 100 ps / m, and the fluctuation of the signal propagation delay time was small. On the other hand, in the printed wiring boards of Comparative Examples 1 and 2 in which the prepreg was formed in one layer, the fluctuation range of the signal propagation delay time (ps / m) exceeded 100 ps / m, and the variation of the signal propagation delay time was large.

  Next, the polyphenylene ether and epoxy compound used in Examples 3 and 4 will be described.

(Polyphenylene ether (3))
As the "polyphenylene ether (3)", polyphenylene ether having a terminal hydroxyl group of polyphenylene ether (SA90 manufactured by SABIC Innovative Plastics) was used. The weight average molecular weight of "polyphenylene ether (3)" is 1700.

(Epoxy compound (1))
As the epoxy compound, a dicyclopentadiene type epoxy compound (“Epiclon HP7200 (trade name)” manufactured by DIC) was used. The number average molecular weight of Epiclon HP7200 is 550.

(Epoxy compound (2))
As the epoxy compound, a naphthalene skeleton-modified epoxy resin (“Epiclone HP4032D (trade name)” manufactured by DIC) was used. The number average molecular weight of Epiclon HP4032D is 280.

  Next, a method of manufacturing the prepreg and the printed wiring board of Examples 3 and 4 will be described.

[Example 3]
30 parts by mass of the above polyphenylene ether (3) was prepared, toluene was added as a solvent, and they were mixed and stirred to be completely dissolved. With respect to the polyphenylene ether solution thus obtained, 45 parts by mass of the above-mentioned epoxy compound (1) and 2,2-bis (4-cyanatophenyl) propane as a cyanate ester compound (Mitsubishi Gas Chemical Co., Ltd. After adding 25 parts by mass of “CA210 (trade name)” manufactured by Co., Ltd., the mixture was stirred for 30 minutes to be completely dissolved. Further, 25 parts by mass of the above-mentioned "SAYTEX 8010" as a flame retardant and 24 parts by mass of the above-mentioned "SC2050" as an inorganic filler were added and dispersed by a ball mill to obtain a resin varnish. The flame retardant was not dissolved and was dispersed in the resin varnish with an average particle size of 1 μm or more and 10 μm or less.

  Next, as a base material, IPC No. The # 1067 E glass cloth was impregnated with the above varnish and then dried by heating at a temperature of 170 ° C. for 5 minutes to remove the solvent to obtain a prepreg having a resin amount of 72 mass% and a thickness of 65 μm. . Using the prepreg thus obtained, a printed wiring board including 12 strip lines having an impedance Z = 50Ω and having a plurality of prepregs laminated between adjacent circuit layers was prepared as in Example 1. The fluctuation range of the propagation delay time when a signal of a predetermined frequency was applied was measured. The evaluation result is shown in FIG.

[Example 4]
In Example 4, 30 parts by mass of the above polyphenylene ether (3), 45 parts by mass of a naphthalene skeleton-modified epoxy resin (HP4032D, manufactured by DIC, number average molecular weight 280), 2,2-bis (4-cyanatephenyl) propane. 25 parts by mass of prepolymer (CA210, manufactured by Mitsubishi Gas Chemical Co., Inc.), 25 parts by mass of ethylene bis (pentabromophenyl) (SAYTEX 8010, manufactured by Albemarle Japan) as a flame retardant, fused silica (SC2050, average particle size 0.5 μm). (Manufactured by Admatechs Co., Ltd.) and mixed with methyl ethyl ketone to a solid content of 65% to obtain a varnish. As a base material, IPC No. The # 1067 E glass cloth was impregnated with the above varnish and then dried by heating at a temperature of 170 ° C. for 5 minutes to remove the solvent to obtain a prepreg having a resin amount of 72 mass% and a thickness of 65 μm. . Using the prepreg thus obtained, a printed wiring board including 12 strip lines having an impedance Z = 50Ω and having a plurality of prepregs laminated between adjacent circuit layers was prepared as in Example 1. The fluctuation range of the propagation delay time when a signal of a predetermined frequency was applied was measured. The evaluation result is shown in FIG.

[Comparative Example 3]
As Comparative Example 3, the same varnish as in Example 3 was used, and IPC No. After impregnating the # 2116 E glass cloth, it was heated and dried at a temperature of 170 ° C. for 5 minutes to remove the solvent to obtain a prepreg having a resin composition of 55% by mass and a thickness of 130 μm. Hereinafter, a printed wiring board was manufactured in the same manner as in Comparative Example 1, and the fluctuation width of the signal propagation delay time was measured. The measurement result is shown in FIG.

[Comparative Example 4]
As Comparative Example 4, the varnish obtained in Example 4 was used, and IPC No. After impregnating the # 2116 E glass cloth, it was heated and dried at a temperature of 170 ° C. for 5 minutes to remove the solvent to obtain a prepreg having a resin composition of 55% by mass and a thickness of 130 μm. Hereinafter, a printed wiring board was prepared in the same manner as in Comparative Example 1, and the fluctuation width of the signal propagation delay time was measured. The measurement result is shown in FIG.

(Evaluation result of propagation delay speed)
FIG. 3 shows the configurations and evaluation results of Examples 3 and 4 and Comparative Examples 3 and 4. As shown in FIG. 3, in the printed wiring boards of Embodiments 3 and 4, the fluctuation range of the signal propagation delay time (ps / m) was less than 100 ps / m, and the fluctuation of the signal propagation delay time was small. On the other hand, in the printed wiring boards of Comparative Examples 3 and 4 in which the prepreg was formed in one layer, the fluctuation range of the signal propagation delay time (ps / m) exceeded 100 ps / m, and the variation of the signal propagation delay time was large.

  As described above, according to the printed wiring boards of Examples 1 to 4 of the present invention, the prepreg is multi-layered to make the distribution of the resin composition and the fiber base material uniform around the wiring. As a result, it is possible to reduce variations in the signal transmission delay time within the plane.

  It should be noted that the present invention is not limited to the above embodiment, and can be modified as appropriate without departing from the spirit of the present invention.

100: printed wiring board, 110: prepreg, 111: insulating layer, 113: insulating layer, 120: resin composition, 130: fiber base material, 150: wiring, 151: wiring, 153: wiring, 900: printed wiring board, 910: prepreg, 920: resin composition, 930: glass fiber base material, 950: wiring, 951: wiring, 953: wiring

Claims (3)

At least one pair insulating layer between the adjacent wires of, Ri plurality of prepregs Tona,
The glass fiber base material contained in the prepreg has a dielectric constant of 7.0 or less,
The resin composition contained in the prepreg contains a polyphenylene ether and a crosslinking type curing agent,
The polyphenylene ether has a number average molecular weight of 1,000 to 7,000 and is represented by the following formula (I):
The volume content based on the specific gravity of the glass fiber substrate is 5% by volume or more and 30% by volume or less,
The volume content based on the specific gravity of the resin composition, a printed wiring board, characterized in der Rukoto 45 vol% to 90 vol%.

[In the formula, X represents an aryl group, (Y) _m represents a polyphenylene ether moiety, R ^{1 to} R ³ independently represent a hydrogen atom, an alkyl group, an alkenyl group, or an alkynyl group, and n is 1 to 6 , And q represents an integer of 1 to 4. ] The insulating layer between at least one pair of adjacent wirings is composed of a plurality of prepregs,
The glass fiber base material contained in the prepreg has a dielectric constant of 7.0 or less,
The resin composition contained in the prepreg is an epoxy compound having a number average molecular weight of 1000 or less, a polyphenylene ether having a number average molecular weight of 5000 or less, and a cyanate ester compound, which does not contain halogen atoms having at least two epoxy groups in one molecule. , a curing catalyst for promoting the reaction between the epoxy compound and the polyphenylene ether and a curing agent wherein the cyanate ester compound, and have a resin varnish containing a halogen-based flame retardant,
The volume content based on the specific gravity of the glass fiber substrate is 5% by volume or more and 30% by volume or less,
The volume content based on the specific gravity of the resin composition, a printed wiring board, characterized in der Rukoto 45 vol% to 90 vol%. Printed circuit board according to claim 1 or 2, characterized in that it comprises a metal, wherein the wire is selected copper, gold, silver and their alloys.