JP6769049B2 - Multi-layer board - Google Patents

Description

The present invention relates to a multilayer substrate. In particular, the present invention relates to a multilayer substrate in which through holes are arranged.

In recent years, the speed and capacity of data communication used in information communication have been rapidly increased. Therefore, in the above electronic devices, there is a demand for a printed wiring board that has both high frequency characteristics and multi-layer wiring.

The 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 shorten the signal propagation delay and reduce the transmission loss. In order to realize these requirements, a resin material containing polyphenylene ether is used as an insulating layer between the multi-layered wirings in the printed wiring board. Polyphenylene ether is a compound that has excellent electrical characteristics (low dielectric constant and low dielectric loss tangent) and is expected to be effective in increasing the transmission speed and reducing the transmission loss. Attempts have been made to apply a laminate of prepregs using this polyphenylene ether to a printed wiring board in order to improve the performance and increase the number of layers of the printed wiring board.

Further, as the performance of the printed wiring board becomes higher and the number of layers increases, the material for the multilayer board used for the printed wiring board is required to be thinner and have higher rigidity. In order to satisfy these requirements, for example, in Patent Document 1 and Patent Document 2, a prepreg using a glass cloth as a base material is used.

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

By the way, as a method of soldering a printed wiring board, a reflow method in which a solder paste is printed on a printed circuit board, and a component is placed on the solder paste and heated is widely used. In addition, since the switch to lead-free solder is progressing, repeated heat treatment at a higher temperature than conventional solder is required. Such repeated heat treatment (thermal cycle) at a high temperature causes the printed wiring board, which is a multilayer board, to be repeatedly expanded and contracted, and in particular, causes delamination in the printed wiring board in which the through holes are arranged.

The present invention has been made in view of such a problem, and an object of the present invention is to provide a multilayer substrate that suppresses lamination in a multilayer substrate in which through holes are arranged.

The multilayer substrate according to the embodiment of the present invention is a multilayer substrate in which a prepreg containing a fiber substrate and a resin composition is laminated, and is a cured product obtained by curing the prepreg at room temperature to 260 ° C. of 20. Total displacement of expansion and contraction in the Z-axis direction in a thermal cycle in which the cycle of heating at ° C./min, holding at 260 ° C. for 5 minutes, and then cooling from 260 ° C. to room temperature at 20 ° C./min was repeated 5 times. The amount is 3.5% or less with respect to the thickness of the cured product before the heating cycle.

Further, the multilayer substrate may be provided with a plurality of through holes, and the distance between the walls of the through holes may be arranged at intervals of 0.25 mm or more and 0.8 mm or less.

Further, the multilayer substrate according to the embodiment of the present invention is a multilayer substrate in which a prepreg containing a fiber substrate and a resin composition is laminated, and the multilayer substrate has a plurality of through holes and cures the prepreg. The cured product thus obtained was heated from room temperature to 260 ° C. at 20 ° C./min, held at 260 ° C. for 5 minutes, and then cooled from 260 ° C. to room temperature at 20 ° C./min, which was repeated 5 times. The total amount of displacement including expansion and contraction in the Z-axis direction in the above is 3.5% or less with respect to the thickness of the cured product before the heating cycle.

ここで、式中、Ｘはアリール基を示し、（Ｙ）_mはポリフェニレンエーテル部分を示し、Ｒ¹〜Ｒ³は独立して水素原子、アルキル基、アルケニル基またはアルキニル基を示す。ｎは１〜６の整数を示し、ｑは１〜４の整数を示す。 Further, the resin composition contains a polyphenylene ether crosslinked curing material, and the number average molecular weight of the polyphenylene ether is 1000 to 7000, 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 represents an integer of 1 to 6, and q represents an integer of 1 to 4.

The resin composition also contains 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, a cyanate ester compound, and an epoxy compound, which do not contain a halogen atom having at least two epoxy groups in one molecule. And a curing catalyst that promotes the reaction between the polyphenylene ether and the cyanate ester compound as a curing agent, and a halogen-based flame retardant may be contained.

Further, the through holes may be formed by filling a metal selected from copper, gold, silver, and alloys thereof.

Further, a wiring layer containing copper, gold, silver, and a metal selected from an alloy thereof may be provided between the laminated prepregs.

According to the present invention, it is possible to provide a multilayer substrate in which delamination is suppressed in a multilayer substrate in which through holes are arranged.

It is a schematic view of the multilayer substrate which concerns on one Embodiment of this invention, (a) shows the top view, (b) shows the sectional view in AA of (a). It is a schematic diagram of the multilayer substrate which concerns on one Embodiment of this invention, and is the enlarged view of the part B of FIG. 1 (b). It is a table which shows the structure and evaluation result of the prepreg which concerns on one Example of this invention. It is a table which shows the structure and evaluation result of the prepreg which concerns on one Example of this invention.

<Embodiment 1>
Hereinafter, the multilayer substrate according to the present invention will be described in detail. However, the multilayer board of the present invention is not construed as being limited to the description contents of the embodiments and examples shown below.

[Multilayer board configuration]
FIG. 1 is a schematic view showing a multilayer substrate 100 according to an embodiment of the present invention. In FIG. 1, (a) shows a top view of a multilayer board 100. Further, (b) shows a cross-sectional view of the multilayer substrate 100 in AA of (a). The multilayer substrate 100 according to the present invention is a multilayer substrate in which a prepreg 10 containing a fiber base material and a resin composition, a metal laminated plate 20, and a metal foil 30 are laminated.

In the present embodiment, the cured product obtained by curing the prepreg constituting the multilayer substrate 100 is heated from room temperature to 260 ° C. at 20 ° C./min, held at 260 ° C. for 5 minutes, and then brought to room temperature from 260 ° C. The total displacement amount of the expansion and contraction in the Z-axis direction (through hole penetration direction) in the heat cycle in which the cycle of cooling at 20 ° C./min to 5 minutes is repeated 5 times is the thickness of the cured product before the heating cycle. It is preferably 3.5% or less.

In the cured product obtained by curing the prepreg, the present inventors have a total displacement amount of the sum of expansion and contraction in the Z-axis direction in the heat cycle of 3 with respect to the thickness of the cured product before the heating cycle. It was found that the displacement can be suppressed by selecting a prepreg having a value of 5.5% or less.

Further, in one embodiment, the multilayer substrate 100 includes a plurality of through holes 50 formed in the laminating direction of the prepreg 10, the metal laminating plate 20, and the metal foil 30. The distance d between the walls of the plurality of through holes is arranged at intervals of 0.25 mm or more and 0.8 mm or less. In the present specification, the distance between the through holes is not the distance between the center lines of the through holes but the distance between the walls of the through holes.

The present inventors have focused on the fact that the narrower the distance between the walls of the through holes, the more likely it is that delamination will occur when a thermal cycle is applied to the multilayer substrate, and the through holes are arranged within the range of the distance d between the walls of the through holes. It was found that the delamination can be suppressed by doing so.

FIG. 2 shows a schematic view of the multilayer substrate 100 according to the embodiment of the present invention. FIG. 2 is an enlarged view of a portion B of FIG. 1 (b). In detail, the multilayer substrate 100 has a configuration in which a prepreg 10 and a metal-clad laminate 20 in which metal layers are arranged on both sides of the prepreg are laminated, but the present invention is not limited thereto. The multilayer board 100 includes, for example, 15 circuit-formed metal-clad laminates 20, the prepregs 10 are alternately arranged between the metal-clad laminates 20, and one prepreg 10 is also provided on the upper and lower outermost layers. It has a structure in which metal foils 30 are arranged one by one. The configuration of the multilayer substrate 100 according to the present invention is not limited to this, and the total number of the prepregs 10 and the metal-clad laminate 20 to be configured can be arbitrarily changed.

[Prepreg configuration]
The prepreg used for the multilayer substrate 100 according to the present invention is a resin composition having a low dielectric constant (Dk) and a dielectric loss tangent (Df), and can suppress delamination due to a thermal cycle.

The prepreg according to the first embodiment of the present invention contains, for example, a polyphenylene ether resin composition as a resin composition, and contains a polyphenylene ether crosslinked curing agent.

(Polyphenylene ether)
The polyphenylene ether contained in the resin composition used for the prepreg according to the first embodiment of the present invention is represented by the following general formula (1), and those having a number average molecular weight of 1000 or more and 7000 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 independently represent a hydrogen atom, an alkyl group, an alkenyl group or an alkynyl group, respectively. .. 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, n is preferably an integer of 1 or more and 4 or less, more preferably n is 1 or 2, and ideally n is 1. Further, preferably, q is an integer of 1 or more and 3 or less, more preferably q is 1 or 2, and ideally q is 1.

(Aryl group)
As the aryl group in the general formula (1), an aromatic hydrocarbon group can be used. Specifically, as the aryl group, a phenyl group, a biphenyl group, an indenyl group, and a naphthyl group can be used, and an aryl group is preferably used. Here, the aryl group includes a 2,2-diphenylpropane group bonded by an alkylene group, such as a diphenyl ether group in which the above aryl group is bonded with an oxygen atom, a benzophenone group bonded with a carbonyl group, and the like. It may be. Further, the aryl group, alkyl group (preferably a C ₁ -C ₆ alkyl group, particularly methyl group), an alkenyl group, an alkynyl group or a halogen atom, may be substituted by common substituent. However, since the "aryl group" is substituted with a polyphenylene ether moiety via an oxygen atom, the limit on 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 represent a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group or an alkenylcarbonyl group, respectively. In the general formula (2), m represents an integer of 1 to 100. Here, the value of m is adjusted so that the number average molecular weight of the polyphenylene ether of the general formula (1) is 1000 or more and 7000 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 1000 or more and 7000 or less.

Here, if the number average molecular weight of the polyphenylene ether exceeds 7,000, the fluidity at the time of molding decreases, and multi-layer molding becomes difficult. On the other hand, if 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 better fluidity, heat resistance, and dielectric properties, the number average molecular weight of the polyphenylene ether is preferably 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 above-mentioned polyphenylene ether having a number average molecular weight has very good compatibility when blended with a crosslinked curing agent. In other words, the smaller the number average molecular weight of polyphenylene ether, the higher the compatibility with the mixture. Therefore, the viscosity increase due to the phase separation is unlikely to occur, and the volatilization of the crosslinked 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, alkenyl group, and alkynyl group in the general formula (2), the same alkyl group, alkenyl group, and alkynyl group in the general formula (1) described below can be used. As the alkenylcarbonyl group of the polyphenylene ether moiety, a carbonyl group substituted with the above alkenyl group can be used. Specifically, an acryloyl group and a methacryloyl group can be used.

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

The polyphenylene ether having the above group at the end has a good interaction with the crosslinked curing agent. Therefore, the heat resistance can be improved and the dielectric constant can be lowered by adding a relatively small amount of the crosslinkable curing agent.

(Alkyl group)
A saturated hydrocarbon group can be used as the alkyl group in the general formula (1) and the general formula (2). As the above alkyl group, a C _{1 −} C ₁₀ alkyl group may be used. Preferably, a C _1- C ₆ alkyl group is used as the above alkyl group. More preferably, a C _1- C ₄ alkyl group may be used as the above alkyl group. More preferably, a C _1- C ₂ alkyl group may be used as the above alkyl group. Specifically, as the alkyl group, 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, and a hexyl group can be used.

(Alkenyl group)
As the alkenyl group in the general formula (1) and the general formula (2), an unsaturated hydrocarbon group having at least one carbon-carbon double bond in the structure can be used. As the above alkenyl group, a C _2- C ₁₀ alkenyl group may be used. Preferably, it is the use of C ₂ -C ₆ alkenyl group as an alkenyl group described above. More preferably, a C _2- C ₄ alkenyl group may be used as the above alkenyl group. Specifically, as the alkenyl group, an ethylene group, a 1-propylene group, a 2-propylene group, an isopropylene group, a butylene group, an isobutylene group, a pentylene group and a hexylene group can be used.

(Alkynyl group)
As the alkynyl group in the general formula (1) and the general formula (2), an unsaturated hydrocarbon group having at least one carbon-carbon triple bond in the structure can be used. As the above-mentioned alkynyl group, a C _2- C ₁₀ alkynyl group may be used. Preferably, a C _2- C ₆ alkynyl group is used as the above-mentioned alkynyl group. More preferably, it is the use of C ₂ -C ₄ alkynyl group as an alkynyl group as described above. Specifically, as the alkynyl group, an ethine group, a 1-propyne group, a 2-propyne group, an isopropine group, a butine group, an isobutyne group, a pentyne group, and a hexyne group can be used.

(Crosslink type curing agent)
As the cross-linking type curing agent contained in the present resin composition, a curing agent for three-dimensionally cross-linking polyphenylene ether can be used. Specifically, as the cross-linking type curing agent, a polyfunctional vinyl compound, a vinylbenzyl ether compound, an allyl ether compound, or a trialkenyl isocyanurate can be used. Polyfunctional vinyl compounds include divinylbenzene, divinylnaphthalene, and divinylbiphenyl. Vinylbenzyl ether compounds are synthesized by the reaction of phenol and vinylbenzyl 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 crosslinkable curing agent. In particular, it is preferable to contain 3 or more and 5 or less functional (meth) acrylate compounds in an amount of 3 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the total amount of the resin composition. Trimethylolpropane trimethacrylate (TMPT) or the like can be used as the functional methacrylate compound of 3 or more and 5 or less, while trimethylolpropane triacrylate or the like can be used as the functional acrylate compound of 3 or more and 5 or less. Can be done. By using the above-mentioned crosslinked 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 lowered as compared with the (meth) acrylate compound having a functionality of 3 or more and 5 or less. Further, even if the (meth) acrylate compound has a functionality of 3 or more and 5 or less, if the content is less than 3 parts by mass with respect to 100 parts by mass of the total amount of the resin composition, the heat resistance of the resin composition is improved. The effect cannot be fully obtained. On the other hand, if it exceeds 20 parts by mass, the dielectric properties and moisture resistance are deteriorated.

The content ratio of the polyphenylene ether and the crosslinked curing agent in the present resin composition is preferably 30/70 or more and 90/10 or less. Preferably, the 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 becomes smaller than the lower limit, the rigidity of the entire resin composition becomes low. As a result, it becomes difficult to make the entire resin composition multi-layered. On the other hand, if the content ratio of polyphenylene ether is larger than the upper limit, the heat resistance of the entire resin composition is lowered. By adjusting the content ratio of the polyphenylene ether and the crosslinkable curing agent within the above range, good fluidity and compatibility of the resin composition can be obtained. Therefore, the embedding property of the resin composition in a via hole or the like can be improved.

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

(Fiber base material)
As the fiber base material contained in the prepreg used for the multilayer substrate 100 according to the embodiment of the present invention, glass cloth such as E glass, D glass, S glass, T glass, NE glass, and quartz can be used. The thickness of the glass cloth is not particularly limited, but it is used for laminated board applications in the range of 0.01 to 0.2 mm, and in particular, a glass woven cloth that has undergone super-opening treatment or filling treatment has dimensions. It is suitable from the viewpoint of stability. Further, glass cloth surface-treated with a silane coupling agent such as epoxy silane treatment or amino silane treatment is preferably used from the viewpoint of moisture absorption and heat resistance. Further, as the fiber base material, an organic fiber base material such as a liquid crystal polyester fiber base material or an aramid fiber base material can also be used.

(Inorganic filler)
The inorganic filler contained in the prepreg used for the multilayer substrate 100 according to the present invention may 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 referred to here may be a value described in a material such as a catalog of the filler 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 size of the filler as the above conditions, a prepreg having high smoothness and reliability can be obtained. In the prepreg of the present invention, by adding silica to the prepreg, an increase in the coefficient of thermal expansion of the prepreg can be effectively suppressed.

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

(Unmodified polyphenylene ether)
In this resin composition, in addition to the above-mentioned polyphenylene ether, unmodified polyphenylene ether having a number average molecular weight of 9000 or more and 18000 or less can be added. By adding unmodified polyphenylene ether, it is possible to control the fluidity of the resin composition and improve the heat resistance. In addition, precipitation of additive components such as fillers can be suppressed in the resin composition. Here, the unmodified polyphenylene ether is a polyphenylene ether having no carbon-carbon unsaturated group in the molecule, and the amount of the polyphenylene ether added is 100 parts by mass in total mass of the polyphenylene ether and the crosslinked curing agent. It is preferably 3 parts by mass or more and 70 parts by mass or less.

Furthermore, in order to improve heat resistance, adhesiveness 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, for example, an aromatic bromine compound can be used. Specifically, decabromodiphenylethane, 4,4-dibromobiphenyl, ethylenebistetrabromophthalimide and the like can be used. Preferably, the brominated organic compound is contained in an amount such that the content of bromine is 8 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the total amount of the resin composition.

If the content of bromine is smaller than the lower limit, the flame retardancy of the prepreg is lowered, and the flame retardancy of UL standard 94V-0 level cannot be maintained. On the other hand, if the content of bromine is larger than the upper limit, bromine tends to dissociate when the prepreg is heated, and the heat resistance of the prepreg is lowered.

(Reaction initiator)
By adding a reaction initiator to the present resin composition, a more remarkable effect of the crosslinked 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 accelerating 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-hexine, benzoyl peroxide. , 3,3', 5,5'-tetramethyl-1,4-diphenoquinone, chloranyl, 2,4,6-tri-t-butylphenoxyl, t-butylperoxyisopropyl monocarbonate, azobisisobutyronitrile And other oxidizing agents can be used. Here, if necessary, a metal carboxylic acid salt or the like may be added to further accelerate the curing reaction.

[Through hole configuration]
In the present embodiment, the through hole 50 is composed of a metal selected from copper, gold, silver, and an alloy thereof, and is formed by filling these metals. In the multilayer substrate 100 according to the present invention, delamination can be suppressed in the multilayer substrate in which the through holes are arranged by the combination of the above-mentioned prepreg and these metals.

Further, in the present embodiment, a wiring layer containing copper, gold, silver, and a metal selected from an alloy thereof is provided between the laminated prepregs. In the present embodiment, the wiring layer is composed of a metal layer arranged on the metal-clad laminate 20. In the multilayer substrate 100 according to the present invention, delamination can be suppressed in the multilayer substrate in which the through holes are arranged by the combination of the above-mentioned prepreg and the metal constituting these wiring layers.

As described above, the multilayer substrate according to the present embodiment can provide a multilayer substrate that suppresses lamination in a multilayer substrate in which through holes are arranged.
[Manufacturing method of prepreg]
A method for producing the prepreg according to the first embodiment of the present invention will be described. First, polyphenylene ether, a crosslinked curing agent, and an additive 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, dissolves the resin component, and adversely affects 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 and the like. One or a mixture of two or more suitable organic solvents of the above is used. The concentration of the resin solid content of the varnish may be appropriately adjusted according to the work of impregnating the base material with the varnish, and may be, for example, 40% by mass or more and 90% by mass or less.

A prepreg can be obtained by impregnating the base material with the above varnish, 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, a glass cloth can be used as the base material.

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

[Manufacturing method of multilayer board (printed wiring board)]
Here, a method for manufacturing the multilayer substrate 100 using the prepreg produced as described above will be described. First, one or a plurality of prepregs are stacked, and then a metal foil such as a copper foil is laminated on both upper and lower surfaces or one side thereof, and the laminate is heat-press molded. By this molding, a laminate having metal foils on both sides or one side can be produced. A multilayer substrate can be obtained by patterning and etching the metal foil of the laminated body to form a circuit. Further, a multilayer substrate can be produced by stacking a plurality of prepregs with a metal foil on which a circuit is formed sandwiched between them and performing heat and pressure molding.

The heating and pressure molding conditions vary depending on the content ratio of the raw materials of the resin composition used, but are 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 higher and 60 kg / cm ^2). It is preferable to heat and pressurize for an appropriate time under the following conditions).

The metal foil used for the multilayer substrate 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). A copper foil whose surface) is treated with zinc or a zinc alloy in order to prevent rust and improve the adhesion to the resin layer, and further treated with a vinyl group-containing silane coupling agent or the like can be used. Such a copper foil has good adhesion to a 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. Further, as the metal forming the wiring layer, in addition to copper, a metal selected from gold, silver, and alloys thereof can also be used.

A through hole is formed by drilling a hole in the stacking direction of the multilayer substrate thus formed. In the multilayer board, the through holes are formed so that the distance between the walls of each through hole is 0.25 mm or more and 0.8 mm or less. Metal plating is applied and the through holes are filled with metal to form through holes.

The multilayer board thus obtained can realize low Dk and low Df. Further, in a multilayer substrate in which through holes are arranged, delamination can be suppressed. Further, it is possible to obtain a printed wiring board having excellent moldability, water resistance, moisture resistance, moisture absorption and heat resistance, and a high glass transition point.

<Embodiment 2>
Hereinafter, the multilayer substrate according to the present invention will be described in detail. However, the multilayer board of the present invention is not construed as being limited to the description contents of the embodiments and examples shown below.

[Multilayer board configuration]
The basic configuration of the multilayer board according to the second embodiment is the same as that of the first embodiment. In the second embodiment, the materials used for the prepregs 10 and 30 of the multilayer substrate 100 are different from those in the first embodiment. In the present embodiment, the inter-wall distances d of the plurality of through holes are arranged at intervals of 0.25 mm or more and 0.8 mm or less. As a result, delamination in the multilayer board can be suppressed.

[Prepreg configuration]
The prepreg according to the second embodiment of the present invention contains an epoxy compound, a polyphenylene ether, a cyanate ester compound, a curing catalyst, and a halogen-based flame retardant. Epoxy compounds have a number average molecular weight of 1000 or less and do not contain halogen atoms having at least two epoxy groups in one molecule. Further, polyphenylene ether has a number average molecular weight of 5000 or less. In addition, the curing catalyst promotes the reaction between the epoxy compound and the polyphenylene ether and the cyanate ester compound which is a 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 and the like can be used. These can be used alone or in combination of two or more. Of the above, a dicyclopentadiene type epoxy compound, a bisphenol A type epoxy compound, a bisphenol F type epoxy compound, and a biphenyl type epoxy compound are particularly preferable because they have good compatibility with polyphenylene ether. The resin composition preferably does not contain a halogenated epoxy compound, but may be added as needed as long as the effects of the present invention are not impaired.

The content ratio of the epoxy compound in the prepreg of the present embodiment is preferably 20 parts by mass or more and 60 parts by mass or less 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. More preferably, the content ratio of the epoxy compound is 30 parts by mass or more and 50 parts by mass or less. By setting the content ratio of the epoxy compound in the above range, sufficient heat resistance and excellent mechanical and electrical properties can be maintained.

(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 5000, the fluidity is deteriorated and the reactivity with the epoxy group is also lowered. Therefore, the curing reaction takes a long time, the number of unreacted substances that are not incorporated into the curing system increases, the glass transition temperature decreases, and sufficient improvement in heat resistance cannot be obtained.

The content ratio of the polyphenylene ether in the prepreg of the present embodiment is preferably 20 parts by mass or more and 60 parts by mass or less 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. More preferably, the content ratio of polyphenylene ether is 20 parts by mass or more and 40 parts by mass or less. When the content ratio of polyphenylene ether is in the above range, excellent dielectric properties can be obtained.

(Cyanide 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 these derivatives can be used. These can 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 for forming an epoxy resin and forms a rigid skeleton. Therefore, a high glass transition point (Tg) can be obtained. Moreover, since the viscosity is low, the high fluidity of the obtained resin varnish can be maintained.

The content ratio of the cyanate ester compound in the prepreg of the present embodiment is 20 parts by mass or more and 60 parts by mass or less 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. preferable. More preferably, the content ratio of the cyanide ester compound is 20 parts by mass or more and 40 parts by mass or less. When the content ratio of the cyanate ester compound is in the above range, sufficient heat resistance can be obtained, the impregnation property to the base material is excellent, and crystals can be prevented from being precipitated even in the resin varnish.

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

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, for example, when an organometallic salt is used. It can be 5 parts by mass or less. Further, for example, when imidazoles are used, the content ratio of the curing catalyst is 0.01 part by mass or more and 5 parts by mass or less with respect to 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 of the resin composition based on the specific gravity 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 and the like can be used. Of the above, ethylenedipentabromobenzene, ethylenebistetrabromophthalimide, decabromodiphenyloxide, and tetradecabromodiphenoxybenzene have high heat resistance at a melting point of 300 ° C. or higher, and therefore, the heat resistance of the prepreg should be improved. Can be done. When a halogen-based flame retardant having a melting point of 300 ° C. or higher and high heat resistance is used, desorption of halogen at high temperature can be suppressed, so that deterioration of heat resistance due to decomposition of the cured product can be suppressed.

The average particle size of the halogen-based flame retardant in the dispersed state is 0.1 μm or more and 50 μm or less, more preferably 1 μm or more and 10 μm or less, so that heat resistance and insulation between layers can be sufficiently maintained. The above average particle size 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 parts by mass or more and 30 parts by mass or less in 100 parts by mass of 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 the content in such a proportion as follows.

(Fiber base material)
As the fiber base material contained in the prepreg of the present invention, glass cloth such as E glass, D glass, S glass, T glass, NE glass, and quartz can be used. The thickness of the glass cloth is not particularly limited, but it is used for laminated board applications in the range of 0.01 to 0.2 mm, and in particular, a glass woven cloth that has undergone super-opening treatment or filling treatment has dimensions. It is suitable from the viewpoint of stability. Further, glass cloth surface-treated with a silane coupling agent such as epoxy silane treatment or amino silane treatment is preferably used from the viewpoint of moisture absorption and heat resistance. Further, as the fiber base material, an organic fiber base material such as a liquid crystal polyester fiber base material or an aramid fiber base material can also be used.

(Inorganic filler)
The inorganic filler contained in the prepreg according to the present embodiment may 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 referred to here may be a value described in a material such as a catalog of the filler 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 size of the filler as the above conditions, a prepreg having high smoothness and reliability can be obtained. In the prepreg of the present invention, by adding silica to the prepreg, an increase in the coefficient of thermal expansion of the prepreg can be effectively suppressed, and as a result, the dielectric constant (Dk) and the dielectric loss tangent (Df) of the entire prepreg can be suppressed. Can be reduced.

In addition to the above-mentioned inorganic filler, the resin composition of the present invention may contain general additive components of the resin composition used for manufacturing electronic devices such as printed wiring boards. For example, heat stabilizers, antistatic agents, ultraviolet absorbers, flame retardants, dyes and pigments, lubricants and the like may be added.

(Other additives)
If necessary, the resin composition of the present invention can be added with an unmodified polyphenylene ether and one or more additives selected from the reaction initiator. Further, a general additive component of the 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.

[Through hole configuration]
In the present embodiment, the through hole 50 is composed of a metal selected from copper, gold, silver, and an alloy thereof, and is formed by filling these metals. In the multilayer substrate 100 according to the present invention, delamination can be suppressed in the multilayer substrate in which the through holes are arranged by the combination of the above-mentioned prepreg and these metals.

Further, in the present embodiment, a wiring layer containing copper, gold, silver, and a metal selected from an alloy thereof is provided between the laminated prepregs. In the present embodiment, the wiring layer is composed of a metal layer arranged on the metal-clad laminate 20. In the multilayer substrate 100 according to the present invention, delamination can be suppressed in the multilayer substrate in which the through holes are arranged by the combination of the above-mentioned prepreg and the metal constituting these wiring layers.

As described above, the multilayer substrate according to the present embodiment can provide a multilayer substrate that suppresses lamination in a multilayer substrate in which through holes are arranged.

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

First, a predetermined amount of an epoxy compound and a cyanate ester compound is dissolved in a resin solution of polyphenylene ether. This dissolution may be carried out at room temperature or while heating. As the epoxy compound and the cyanate ester compound, the formation of precipitates in the resin varnish can be suppressed by using a material that dissolves in a solvent such as toluene at room temperature.

Here, when an inorganic filler is added as an additive, a resin varnish is prepared by adding the filler and then dispersing the filler until a predetermined dispersion state is obtained using a ball mill, a bead mill, a planetary mixer, a roll mill, or the like. Will be done.

A prepreg can be obtained by impregnating the base material with the resin varnish obtained as described above and drying it by the same production method as in the first embodiment. Further, a multilayer substrate can be obtained by the same manufacturing method as in the first embodiment.

Hereinafter, the results of producing the multilayer substrate according to the first and second embodiments of the present invention and evaluating the amount of displacement in the Z-axis direction and the presence or absence of delamination will be specifically described. Examples 1 to 3 shown below correspond to the examples of the first embodiment, and Examples 4 to 7 correspond to the examples of the second embodiment.

First, the polyphenylene ether used in Examples 1 to 3 will be described.

(Polyphenylene ether (1))
CuBr ₂ 3.88 g (17.4 mmol), N, N'-di-t-butylethylenediamine 0.75 g (4.) in a 12 liter longitudinal reactor with agitator, thermometer, air inlet tube and baffle plate. 4 mmol), 28.04 g (277.6 mmol) of n-butyldimethylamine, and 2600 g of toluene were charged, stirred at a reaction temperature of 40 ° C., and 2,2', 3,3', which had been previously dissolved in 2300 g of methanol. 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 A mixed solution of 64.9 g (0.48 mol) of 6-trimethylphenol, 0.51 g (2.9 mmol) of N, N'-di-t-butylethylenediamine, and 10.90 g (108.0 mmol) of n-butyldimethylamine. , Nitrogen and air were mixed to adjust the oxygen concentration to 8%, and the mixed gas was added dropwise over 230 minutes while bubbling at a flow rate of 5.2 liters / min, and the mixture was stirred.

After completion of the dropwise addition, 1500 g of water in which 19.89 g (52.3 mmol) of ethylenediaminetetraacetic acid tetrasodium was dissolved was added, and the reaction was stopped. The aqueous layer and the organic layer were separated, and the organic layer was washed with a 1N aqueous hydrochloric acid solution and then 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 (resin "A"). The number average molecular weight of the resin "A" was 986, the weight average molecular weight was 1530, and the hydroxyl group equivalent was 471.

A reactor equipped with a stirrer, a thermometer, and a reflux tube contains 836.5 g of a toluene solution of resin "A", 162.6 g of vinylbenzyl chloride (trade name: CMS-P; manufactured by Seimi Chemical Co., Ltd.), 1600 g of methylene chloride. 12.95 g of benzyldimethylamine, 420 g of pure water, and 178.0 g of a 30.5 wt% NaOH aqueous solution 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 1N aqueous hydrochloric acid solution and then pure water. The obtained solution was concentrated with an evaporator, dropped into methanol to solidify, and the solid was recovered by filtration and vacuum dried to obtain 503.5 g of "polyphenylene ether (1)". The number average molecular weight of "polyphenylene ether (1)" was 1187, the weight average molecular weight was 1675, and the vinyl group equivalent was 590 g / vinyl group.

(Polyphenylene ether (2))
CuBr ₂ 9.36 g (42.1 mmol), N, N'-di-t-butylethylenediamine 1.81 g (10.) in a 12 liter longitudinal reactor with agitator, thermometer, air inlet tube and baffle plate. 5 mmol), 67.77 g (671.0 mmol) of n-butyldimethylamine, and 2600 g of toluene were charged, stirred at a reaction temperature of 40 ° C., and 2,2', 3,3', which had been previously dissolved in 2300 g of methanol. 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 was mixed with nitrogen and air to adjust the oxygen concentration to 8%. The gas was added dropwise over 230 minutes while bubbling at a flow rate of 5.2 liters / min, and the mixture was stirred.

After completion of the dropping, 1500 g of water in which 48.06 g (126.4 mmol) of ethylenediaminetetraacetic acid tetrasodium was dissolved was added, and the reaction was stopped. The aqueous layer and the organic layer were separated, and the organic layer was washed with a 1N aqueous hydrochloric acid solution and then 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 (resin "B"). The number average molecular weight of the resin "B" was 1975, the weight average molecular weight was 3514, and the hydroxyl group equivalent was 990.

A reactor equipped with a stirrer, a thermometer, and a reflux tube contains 833.4 g of a toluene solution of resin "B", 76.7 g of vinylbenzyl chloride (trade name: CMS-P; manufactured by Seimi Chemical Co., Ltd.), 1600 g of methylene chloride. 6.2 g of benzyldimethylamine, 199.5 g of pure water, and 83.6 g of a 30.5 wt% NaOH aqueous solution 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 1N aqueous hydrochloric acid solution and then pure water. The obtained solution was concentrated with an evaporator, dropped into methanol for solidification, and the solid was recovered by filtration and vacuum dried to obtain 450.1 g of "polyphenylene ether (2)". The number average molecular weight of the vinyl "polyphenylene ether (2)" was 2250, the weight average molecular weight was 3920, and the vinyl group equivalent was 1189 g / vinyl group.

Next, a method for manufacturing the prepreg and the multilayer substrate of Examples 1 to 3 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, and the mixture was mixed at 80 ° C. for 30 minutes and stirred to completely dissolve. With respect to the polyphenylene ether solution thus obtained, 30 parts by mass of "TAIC" manufactured by Nihon Kasei Co., Ltd. as a crosslinkable curing agent and ethylenebis (pentabromophenyl) (Albemar), which is a brominated organic compound, as a flame retardant. 20 parts by mass of "SAYTEX8010 (trade name)" manufactured by Japan Co., Ltd. and 24 parts by mass of spherical synthetic silica ("SC2050 (trade name)" manufactured by Admatex Co., Ltd.) as an inorganic filler were blended. These were mixed, dispersed and dissolved in toluene as a solvent, and diluted with toluene to a solid content of 65% to obtain a varnish of a resin composition. Since the flame retardant is a brominated organic compound that does not react with polyphenylene ether and TAIC, the flame retardant was dispersed in the varnish, which is a resin composition, without being dissolved in toluene.

Next, as a base material, IPC No. After impregnating the above varnish with # 3313 E glass cloth, the resin composition was heat-dried at a temperature of 170 ° C. for 5 minutes to remove the solvent, and the resin composition was 55% by volume and 0.1 mm thick. I got a prepreg. Eight prepregs thus obtained were stacked, and copper foils (3EC-III, manufactured by Mitsui Mining & Smelting Co., Ltd.) having a thickness of 18 μm were laminated on the upper and lower sides thereof. A double-sided copper-clad laminate having a thickness of 0.8 mm was obtained by heating and pressurizing under molding conditions of a temperature of 220 ° C., a pressure of 3.0 MPa (30 kg / cm ² ), and 120 minutes. Next, using the obtained copper-clad laminate, the amount of displacement in the Z-axis direction after the thermal cycle test was evaluated. The evaluation results are shown in FIG.

Further, a 35 μm-thick electrolytic copper foil (3EC-III, manufactured by Mitsui Mining & Smelting Co., Ltd.) was placed vertically on the 0.1 mm-thick prepreg obtained as described above, and the pressure was 3.0 MPa (30 kg / cm ² ) and the temperature. Lamination molding was performed at 220 ° C. for 120 minutes to obtain a copper-clad laminate having an insulating layer thickness of 0.1 mm. As a base material, IPC No. The varnish was impregnated with # 2116 E glass cloth and heated at 170 ° C. for 5 minutes to obtain a prepreg having a resin amount of 55% and a thickness of 0.13 mm.

Fifteen 0.1 mm double-sided copper-clad laminates obtained as described above were prepared. A circuit is formed on this double-sided copper-clad laminate, and the 0.13 mm thick prepregs obtained above are alternately arranged between the double-sided copper-clad laminates, and the upper and lower outermost layers also have the above 0.13 mm. The prepregs of the above were laminated one by one, and an electrolytic copper foil (3EC-III, manufactured by Mitsui Mining & Smelting Co., Ltd.) having a thickness of 18 μm was further arranged (pressure 3.0 MPa (30 kg / cm ² ), temperature 200 ° C. 60. A 32-layer substrate was obtained by performing press laminating molding (for minutes) and adhesive curing.

Through holes for evaluating through-hole connection reliability having a hole diameter of 0.25 mm were provided by drilling in the stacking direction of the multilayer substrate. The distance between the walls of the through holes of the multilayer board was set to 0.55 mm, and copper plating was performed to form a copper plating layer having a thickness of 15 μm. Circuits were formed on both sides of the obtained multilayer board, and delamination evaluation was performed after the thermal cycle test. The evaluation results are shown in FIG.

[Example 2]
In Example 2, 70 parts by mass of the above 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. With respect to the polyphenylene ether solution thus obtained, 30 parts by mass of "TAIC" manufactured by Nihon Kasei Co., Ltd. was used as a cross-linking curing agent, and ethylene bis (pentabromophenyl) (Albemar), which is a brominated organic compound, was used as a flame retardant. 20 parts by mass of "SAYTEX8010 (trade name)" manufactured by Japan Co., Ltd. and 24 parts by mass of spherical synthetic silica ("SC2050 (trade name)" manufactured by Admatex Co., Ltd.) as an inorganic filler were blended. These were mixed, dispersed and dissolved in toluene as a solvent, and diluted with toluene to a solid content of 65% to obtain a varnish of a resin composition. Since the flame retardant is a brominated organic compound that does not react with polyphenylene ether and TAIC, the flame retardant was dispersed in the varnish, which is a resin composition, without being dissolved in toluene.

Next, as a base material, IPC No. After impregnating the above varnish with # 2116 E glass cloth, the mixture 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 volume. Hereinafter, a copper-clad laminate was produced in the same manner as in Example 1, and the amount of displacement in the Z-axis direction after the thermal cycle test was evaluated. The evaluation results are shown in FIG.

Further, a 32-layer substrate was prepared in the same manner as in Example 1. Through holes for evaluating through-hole connection reliability having a hole diameter of 0.25 mm were provided by drilling in the stacking direction of the multilayer substrate. The distance between the walls of the through holes of the multilayer board was set to 0.55 mm, and copper plating was performed to form a copper plating layer having a thickness of 15 μm. Circuits were formed on both sides of the obtained multilayer board, and delamination evaluation was performed after the thermal cycle test. The evaluation results are shown in FIG.

[Example 3]
As Example 3, the varnish obtained in Example 1 was used, and the distance between the walls of a 32-layer substrate using a copper-clad laminate having a thickness of 0.1 mm and a prepreg having a thickness of 0.13 mm was set to 0.7 mm. A copper-clad laminate having a thickness of 0.8 mm and a 32-layer substrate having a through-hole wall spacing of 0.7 mm were obtained by the same method as in Example 1. Table 3 shows the physical property evaluation results of the obtained copper-clad laminate with a thickness of 0.8 mm and the 32-layer substrate.

[Comparative Example 1]
As Comparative Example 1, 85 parts by mass of bisphenol A type epoxy resin (E1123P, manufactured by DIC), 15 parts by mass of cresol novolac type epoxy resin (N-680, manufactured by DIC), and dicyandiamide (DICY (D25F)) as a curing agent. (Manufactured by Nippon Carbide) 2.5 parts by mass was mixed and diluted with toluene to a solid content of 65% to obtain a varnish.

Using the obtained varnish, a prepreg having a thickness of 0.1 mm, a copper-clad laminate using a prepreg having a thickness of 0.1 mm, and a prepreg having a thickness of 0.13 mm were prepared in the same manner as in Example 1 to obtain a thickness. The production of the 32-layer substrate using the 0.1 mm thick copper-clad laminate and the 0.13 mm thick prepreg was performed in the same manner as in Example 1, and the distance between the 0.8 mm thick copper-clad laminate and the through-hole wall. A 0.55 mm 32-layer substrate was obtained. FIG. 3 shows the results of physical property evaluation of the obtained copper-clad laminate having a thickness of 0.8 mm and the 32-layer substrate.

[Comparative Example 2]
As Comparative Example 2, the varnish obtained in Comparative Example 1 was used, and the distance between the through-hole walls of a 32-layer substrate using a copper-clad laminate having a thickness of 0.1 mm and a prepreg having a thickness of 0.13 mm was set to 0. A copper-clad laminate having a thickness of 0.8 mm and a 32-layer substrate having a through-hole wall distance of 0.7 mm were obtained by the same method as in Example 1 except that the thickness was 7 mm. FIG. 3 shows the evaluation results of the obtained copper-clad laminate and multilayer substrate having a thickness of 0.8 mm.

[Comparative Example 3]
As Comparative Example 3, 85 parts by mass of bisphenol A type epoxy resin (E1123P, manufactured by DIC), 15 parts by mass of cresol novolac type epoxy resin (N-680, manufactured by DIC), and dicyandiamide (DICY (D25F)) as a curing agent. 2.5 parts by mass of (manufactured by Nippon Carbide) and 32 parts by mass of calcined talc (BST200L, manufactured by Nippon Tarku) were mixed and diluted with toluene to a solid content of 65% to obtain a varnish.

Using the obtained varnish, a prepreg having a thickness of 0.1 mm, a copper-clad laminate using a prepreg having a thickness of 0.1 mm, and a prepreg having a thickness of 0.13 mm were prepared in the same manner as in Example 1 to obtain a thickness. The production of the 32-layer substrate using the 0.1 mm thick copper-clad laminate and the 0.13 mm thick prepreg was performed in the same manner as in Example 1, and the distance between the 0.8 mm thick copper-clad laminate and the through-hole wall. A 0.55 mm 32-layer substrate was obtained. FIG. 3 shows the evaluation results of the obtained copper-clad laminate and multilayer substrate having a thickness of 0.8 mm.

[Comparative Example 4]
As Comparative Example 4, the varnish obtained in Comparative Example 3 was used, and the distance between the through-hole walls of a 32-layer substrate using a copper-clad laminate having a thickness of 0.1 mm and a prepreg having a thickness of 0.13 mm was set to 0. The same procedure as in Example 1 was carried out except that the thickness was 7 mm, and a copper-clad laminate having a thickness of 0.8 mm and a 32-layer substrate having a through-hole wall distance of 0.7 mm were obtained. FIG. 3 shows the evaluation results of the obtained copper-clad laminate and multilayer substrate having a thickness of 0.8 mm.

(Measurement of displacement in the Z-axis direction)
The copper foil of the copper-clad laminate with an insulating layer thickness of 0.8 mm is removed, heated from room temperature to 260 ° C. at 20 ° C./min, held at 260 ° C. for 5 minutes, and then cooled from 260 ° C. to room temperature at 20 ° C./min. The total displacement amount including the expansion and contraction in the Z-axis direction in the thermal cycle in which the cooling cycle was repeated 5 times was measured.

(Delamination evaluation)
The multilayer substrate was reflowed from room temperature to a maximum temperature of 260 ° C., the step of cooling to room temperature was repeated 10 times, and the presence or absence of delamination between layers was confirmed by cross-section polishing after the heat cycle.

FIG. 3 shows the configurations and evaluation results of Examples 1 to 3 and Comparative Examples 1 to 4.

As shown in FIG. 3, in the copper-clad laminates of the first to third embodiments using the prepreg according to the present invention, the displacement amount in the Z-axis direction before and after the thermal cycle is 3% or less, and delamination is suppressed. It was suggested that it would be done. On the other hand, in the copper-clad laminates of Comparative Examples 1 to 4 formed of a material different from the prepreg according to the present invention, the amount of displacement in the Z-axis direction before and after the thermal cycle exceeds 3%, suggesting that delamination may occur. did. Further, as a result of delamination evaluation of the multilayer boards of Examples 1 to 3 and Comparative Examples 1 to 4, no delamination was observed in the multilayer boards of Examples 1 to 3, but comparison was made. Delamination occurred in the multilayer boards of Examples 1 to 4. From these results, it was clarified that in the multilayer substrate according to the present invention, delamination does not occur even if a thermal cycle is applied.

Subsequently, the polyphenylene ether and the epoxy compound used in Examples 4 to 7 will be described.

(Polyphenylene ether (3))
As the "polyphenylene ether (3)", a polyphenylene ether (SA90 manufactured by SABIC Innovative Plastics Co., Ltd.) having a hydroxyl group at the end of the polyphenylene ether 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 Epicron HP7200 is 550.

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

Next, a method for manufacturing the prepreg and the multilayer substrate of Examples 4 to 7 will be described.

[Example 4]
30 parts by mass of the above polyphenylene ether (3) was prepared, toluene was added as a solvent, and the mixture was mixed and stirred to completely dissolve it. With respect to the polyphenylene ether solution thus obtained, 45 parts by mass of the above epoxy compound (1) and 2,2-bis (4-cyanatophenyl) propane (Mitsubishi Gas Chemicals) as a cyanate ester compound. After adding 25 parts by mass of "CA210 (trade name)" manufactured by Co., Ltd., the mixture was completely dissolved by stirring for 30 minutes. Further, 25 parts by mass of the above "SAYTEX8010" as a flame retardant and 24 parts by mass of the above "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. After impregnating the above varnish with # 3313 E glass cloth, the mixture was heated and dried at a temperature of 170 ° C. for 5 minutes to remove the solvent to obtain a prepreg having a resin amount of 55%. Eight prepregs thus obtained were stacked, and copper foils (3EC-III, manufactured by Mitsui Mining & Smelting Co., Ltd.) having a thickness of 18 μm were laminated on the upper and lower sides thereof. A double-sided copper-clad laminate for a printed wiring board having a thickness of 0.8 mm was obtained by heating and pressurizing under molding conditions of a temperature of 210 ° C., a pressure of 3.0 MPa (30 kg / cm ² ), and 150 minutes. Next, using the obtained copper-clad laminate, the amount of displacement in the Z-axis direction after the thermal cycle test was evaluated. The evaluation results are shown in FIG.

Further, a 35 μm-thick electrolytic copper foil (3EC-III, manufactured by Mitsui Mining & Smelting Co., Ltd.) was placed vertically on the 0.1 mm-thick prepreg obtained above, and the pressure was 3.0 MPa (30 kg / cm ² ) and the temperature was Lamination molding was performed at 220 ° C. for 120 minutes to obtain a copper-clad laminate having an insulating layer thickness of 0.1 mm. As a base material, IPC No. The varnish was impregnated with # 2116 E glass cloth and heated at 170 ° C. for 5 minutes to obtain a prepreg having a resin amount of 55% and a thickness of 0.13 mm.

Fifteen 0.1 mm double-sided copper-clad laminates obtained as described above were prepared. A circuit is formed on this double-sided copper-clad laminate, and the 0.13 mm thick prepregs obtained above are alternately arranged between the double-sided copper-clad laminates, and the upper and lower outermost layers also have the above 0.13 mm. The prepregs of the above were laminated one by one, and an electrolytic copper foil (3EC-III, manufactured by Mitsui Mining & Smelting Co., Ltd.) having a thickness of 18 μm was further arranged (pressure 3.0 MPa (30 kg / cm ² ), temperature 200 ° C. 60. A 32-layer substrate was obtained by performing press laminating molding (for minutes) and adhesive curing.

Through holes for evaluating through-hole connection reliability having a hole diameter of 0.25 mm were provided by drilling in the stacking direction of the multilayer substrate. The distance between the walls of the through holes of the multilayer board was set to 0.55 mm, and copper plating was performed to form a copper plating layer having a thickness of 15 μm. Circuits were formed on both sides of the obtained multilayer board, and delamination evaluation was performed after the thermal cycle test. The evaluation results are shown in FIG.

[Example 5]
In Example 5, 30 parts by mass of the above polyphenylene ether (3) was prepared, toluene was added as a solvent, and the mixture was mixed and stirred to completely dissolve it. With respect to the polyphenylene ether solution thus obtained, 45 parts by mass of the above epoxy compound (2) and 2,2-bis (4-cyanatophenyl) propane (Mitsubishi Gas Chemicals) as a cyanate ester compound. After adding 25 parts by mass of "CA210 (trade name)" manufactured by Co., Ltd., the mixture was completely dissolved by stirring for 30 minutes. Further, 25 parts by mass of the above "SAYTEX8010" as a flame retardant and 24 parts by mass of the above "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. After impregnating the above varnish with the E glass cloth of # 3313, the mixture 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 volume. Eight prepregs thus obtained were stacked, and copper foils (3EC-III, manufactured by Mitsui Mining & Smelting Co., Ltd.) having a thickness of 18 μm were laminated on the upper and lower sides thereof. A double-sided copper-clad laminate having a thickness of 0.8 mm was obtained by heating and pressurizing under molding conditions of a temperature of 210 ° C., a pressure of 3.0 MPa (30 kg / cm ² ), and 150 minutes. Next, using the obtained copper-clad laminate, the amount of displacement in the Z direction after the thermal cycle test was evaluated. The evaluation results are shown in FIG.

Further, a 35 μm-thick electrolytic copper foil (3EC-III, manufactured by Mitsui Mining & Smelting Co., Ltd.) was placed vertically on the 0.1 mm-thick prepreg obtained as described above, and the pressure was 3.0 MPa (30 kg / cm ² ) and the temperature. Lamination molding was performed at 220 ° C. for 120 minutes to obtain a copper-clad laminate having an insulating layer thickness of 0.1 mm. As a base material, IPC No. The varnish was impregnated with # 2116 E glass cloth and heated at 170 ° C. for 5 minutes to obtain a prepreg having a resin amount of 55% and a thickness of 0.13 mm.

Fifteen 0.1 mm double-sided copper-clad laminates obtained as described above were prepared. A circuit is formed on this double-sided copper-clad laminate, and the 0.13 mm thick prepregs obtained above are alternately arranged between the double-sided copper-clad laminates, and the upper and lower outermost layers also have the above 0.13 mm. The prepregs of the above were laminated one by one, and an electrolytic copper foil (3EC-III, manufactured by Mitsui Mining & Smelting Co., Ltd.) having a thickness of 18 μm was further arranged (pressure 3.0 MPa (30 kg / cm ² ), temperature 200 ° C. 60. A 32-layer substrate was obtained by performing press laminating molding (for minutes) and adhesive curing.

Through holes for evaluating through-hole connection reliability having a hole diameter of 0.25 mm were provided by drilling in the stacking direction of the multilayer substrate. The distance between the walls of the through holes of the multilayer board was set to 0.55 mm, and copper plating was performed to form a copper plating layer having a thickness of 15 μm. Circuits were formed on both sides of the obtained multilayer board, and delamination evaluation was performed after the thermal cycle test. The evaluation results are shown in FIG.

[Example 6]
In Example 6, 20 parts by mass of polyphenylene ether (SA90, manufactured by SABIC Innovation Plastic Co., Ltd., number average molecular weight 1700), 55 parts by mass of dicyclopentadiene type epoxy resin (Epicron HP7200, manufactured by DIC, number average molecular weight 550), 2, 25 parts by mass of 2-bis (4-cyanatephenyl) propane prepolymer (CA210, manufactured by Mitsubishi Gas Chemicals), 25 parts by mass of ethylene bis (pentabromophenyl) (SAYTEX8010, manufactured by Albemar Japan) as a flame retardant, molten silica 24 parts by mass (SC2050, average particle size 0.5 μm, manufactured by Admatex Co., Ltd.) was mixed and diluted with toluene to a solid content of 65% to obtain a varnish.

A prepreg having a thickness of 0.1 mm, a copper-clad laminate using a prepreg having a thickness of 0.1 mm, a prepreg having a thickness of 0.13 mm and a copper-clad laminate having a thickness of 0.1 mm using the obtained varnish. A 32-layer substrate using a prepreg having a thickness of 0.13 mm was produced in the same manner as in Example 1 to obtain a copper-clad laminate having a thickness of 0.8 mm and a 32-layer substrate having a through-hole wall distance of 0.55 mm. .. FIG. 4 shows the evaluation results of the obtained copper-clad laminate and multilayer substrate having a thickness of 0.8 mm.

[Example 7]
In Example 7, 20 parts by mass of polyphenylene ether (SA90, manufactured by SABIC Innovation Plastics, number average molecular weight 1700), 55 parts by mass of naphthalene skeleton-modified epoxy resin (HP4032D, manufactured by DIC, number average molecular weight 280), 2,2- 25 parts by mass of prepolymer of bis (4-cyanatephenyl) propane (CA210, manufactured by Mitsubishi Gas Chemicals), 25 parts by mass of ethylene bis (pentabromophenyl) (SAYTEX8010, manufactured by Albemar Japan) as a flame retardant, molten silica ( 24 parts by mass of SC2050, average particle size 0.5 μm, manufactured by Admatex Co., Ltd.) was mixed and diluted with toluene to a solid content of 65% to obtain a varnish.

A prepreg having a thickness of 0.1 mm, a copper-clad laminate using a prepreg having a thickness of 0.1 mm, a prepreg having a thickness of 0.13 mm and a copper-clad laminate having a thickness of 0.1 mm using the obtained varnish. A 32-layer substrate using a prepreg having a thickness of 0.13 mm was produced in the same manner as in Example 1 to obtain a copper-clad laminate having a thickness of 0.8 mm and a 32-layer substrate having a through-hole wall distance of 0.55 mm. .. FIG. 4 shows the evaluation results of the obtained copper-clad laminate and multilayer substrate having a thickness of 0.8 mm.

FIG. 4 shows the configurations and evaluation results of Examples 4 to 7.

As shown in FIG. 4, in the copper-clad laminates of the fourth to seventh embodiments using the prepreg according to the present invention, the displacement amount in the Z-axis direction before and after the thermal cycle is 3% or less, and delamination is suppressed. It was suggested that it would be done. Further, as a result of the delamination evaluation of the multilayer boards of Examples 4 to 7, no delamination was observed. From these results, it was clarified that in the multilayer substrate according to the present invention, delamination does not occur even if a thermal cycle is applied.

As described above, according to the copper-clad laminates according to Examples 1 to 7 of the present invention, the amount of displacement in the Z-axis direction before and after the thermal cycle is 3% or less, and delamination can be suppressed. Further, according to the multilayer substrate according to the first to seventh embodiments of the present invention, delamination can be suppressed even if a thermal cycle is applied.

The present invention is not limited to the above embodiment, and can be appropriately modified without departing from the spirit.

10: prepreg, 20: metal-clad laminate, 30: metal foil, 50: through-hole, 100: multilayer substrate

Claims (3)

A multilayer substrate in which a prepreg containing a fiber base material and a resin composition is laminated.
The cured product obtained by curing the prepreg is heated from room temperature to 260 ° C. at 20 ° C./min, held at 260 ° C. for 5 minutes, and then cooled from 260 ° C. to room temperature at 20 ° C./min five times. The total displacement amount of the expansion and contraction in the Z-axis direction in the repeated heat cycle is 3.5% or less with respect to the thickness of the cured product before the heating cycle.
The multilayer board includes a plurality of through holes, and the distance between the walls of the through holes is arranged at intervals of 0.25 mm or more and 0.55 mm or less.
The resin composition is
It contains a polyphenylene ether and a cross-linked curing agent, the polyphenylene ether has a number average molecular weight of 1000 to 7000, and has a resin composition represented by the following formula (I) or at least two epoxy groups in one molecule. 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, a cyanate ester compound, the epoxy compound, and the polyphenylene ether and the cyanate ester compound as a curing agent, which do not contain a halogen atom, are promoted. A multilayer substrate characterized by being a resin composition containing a curing catalyst and a halogen-based flame retardant.

[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. Indicates an integer of, and q indicates an integer of 1 to 4. ] The multilayer substrate according to claim 1, wherein the through holes are formed by filling a metal selected from copper, gold, silver, and an alloy thereof. The multilayer substrate according to claim 1 or 2, wherein a wiring layer containing copper, gold, silver, and a metal selected from an alloy thereof is provided between the laminated prepregs.

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