JPH08236943A - Multilayered circuit board - Google Patents

Abstract

PURPOSE: To obtain a flame-retardant thin multilayered circuit board having an excellent heat resistance, moisture resistance, insulating property, dimensional stability, and chemical resistance and a high strength of bond by using a hardened material of a specific curable polyphenylene ether resin composition. CONSTITUTION: The interlayer insulator of a multilayered circuit board contains a resulted product of reaction between polyphenylene ether and unsaturated carboxylic acid or its anhydride (a), triallyl isocyanurate and/or triallyl cyanurate (b), and curable polyphenylene ether resin composition containing a flame-retardant agent produced from the compound expressed by the formula (where, m and n respectively represent integers of 3-5, with the sum of m and n being >=8, and z represent an alkyl group or bromoalkyl group) with its carbon number of 4 or less. The mixing ratios of the components (a) and (b) are respectively adjusted to 98-40 pts.wt. and 2-60 pts.wt. against the sum (100 pts.wt.) of the components (a) and (b) and the mixing ratios of the sum of the components (a) and (b) and component (c) are respectively adjusted to 95-50 pts.wt. and 5-50 pts.wt. against the sum (100 pts.wt.) of the components (a), (b), and (c).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an interlayer insulating material for a multilayer circuit board used in various electric devices. More specifically, the present invention relates to a multilayer circuit board having an interlayer insulating material having excellent chemical resistance, heat resistance, flame retardancy, and dimensional stability as one of the constituent materials. Further, the present invention provides
Since a specific interlayer insulating material having the above-mentioned function is used, a thinner multilayer circuit board is provided.

[0002]

2. Description of the Related Art In recent years, there has been a remarkable trend toward miniaturization and high density of mounting methods in the field of electronic devices for communication, consumer use, industrial use, etc. Heat resistance, dimensional stability, electrical characteristics, and moldability are being demanded. For example, as a printed wiring board, a copper-clad laminate having a thermosetting resin such as a phenol resin or an epoxy resin as a base material has been conventionally used. Although these have various performances in good balance, their electrical characteristics,
Especially, there is a problem that the dielectric property is bad in a high frequency region. Polyphenylene ether has recently attracted attention as a new material to solve this problem, and its application to copper-clad laminates has been attempted.

Polyphenylene ether is an engineering plastic excellent in mechanical properties and electrical properties and has relatively high heat resistance. However, when it is intended to be used as a printed circuit board material, extremely high solder heat resistance is required, so that it cannot be said that the original heat resistance of polyphenylene ether is sufficient. That is, the polyphenylene ether is deformed when exposed to a high temperature of 200 ° C. or higher, causing a significant decrease in mechanical strength and peeling of the copper foil formed on the resin surface for a circuit. Further, although polyphenylene ether has acid resistance, alkali resistance, and hot water resistance, it has poor solvent resistance to aromatic hydrocarbons and halogen-substituted hydrocarbon compounds and is soluble in these solvents.

As one method for improving the heat resistance and chemical resistance of polyphenylene ether, a method has been proposed in which a crosslinkable functional group is introduced into the chain of polyphenylene ether and further cured to be used as a cured polyphenylene ether. There is. As a specific example, a polymer of 2-allyl-6-methylphenol or 2,6-diallylphenol is Journal of Polymer Scie.
nce, 49, 267 (1961). U.S. Pat. Nos. 3,281,393 and 3,422,062 disclose copolymers of 2,6-dimethylphenol with 2-allyl-6-methylphenol or 2,6-diallylphenol. It is disclosed. Also, US Pat. No. 4,634,742 discloses vinyl-substituted polyphenylene ethers.

Furthermore, the present inventors have found that polyphenylene ethers previously substituted with a propargyl group or an allyl group,
We proposed a polyphenylene ether containing a triple bond or a double bond and an unsaturated carboxylic acid or its acid anhydride-modified polyphenylene ether, which can be cured, and the resulting cured product is an aromatic hydrocarbon solvent or a halogen-substituted hydrocarbon. It has been found that it is insoluble in hydrogen solvents and has excellent dielectric properties (JP-A-1-69628, 1).
-69629, 1-131425, 1-11
3426 and 4-239017). But,
Polyphenylene ether itself does not have sufficient flame retardancy for use in electrical components such as copper clad laminates. Although it is practically strongly demanded to impart flame retardancy without impairing the excellent dielectric properties and heat resistance of polyphenylene ether, the addition of decabromodiphenyl ether analog compound, which is an effective means thereof, is environmentally friendly. From the viewpoint of protection, there is a direction of restriction or prohibition.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has excellent chemical resistance and heat resistance after curing without impairing the excellent dielectric properties of polyphenylene ether resin. In addition, it is intended to provide a novel curable resin composition exhibiting excellent flame retardancy. Further, the present invention is to solve the problem of heat-resistant and moisture-proof insulation of a high-density circuit board, and particularly to solve the problem with a thin multilayer circuit board having an interlayer insulating layer thickness of 200 μm or less, and further 100 μm or less. Is.

[0007]

As a result of various studies for solving the above-mentioned problems, the present inventor has found that a cured product of a specific curable polyphenylene ether resin composition is used as an interlayer insulating material of a multilayer circuit board. In addition to having excellent heat and moisture resistant insulation, dimensional stability, and chemical resistance, it also has excellent flame retardancy and high adhesive strength between prepregs, high integration, and high reliability. They have found that a multilayer circuit board can be obtained, and have completed the present invention. Ie:

According to the present invention, the conductor line insulating material formed on the insulating substrate is (a) a reaction product of polyphenylene ether and an unsaturated carboxylic acid or acid anhydride, (b) triallyl isocyanurate and / or Alternatively, a curable polyphenylene ether resin composition containing triallyl cyanurate and a flame-retardant material composed of a compound represented by the following general formula (1): 100 parts by weight of the sum of components (a) and (b) The component (a) is 98 to 40 parts by weight based on
The component (b) is 2 to 60 parts by weight, and (a) to
(A) + based on 100 parts by weight of the sum of components (c)
Component (b) is 95-50 parts by weight, component (c) is 5-50.
Provided is a multilayer circuit board, which is a cured product of a curable polyphenylene ether resin composition composed of parts by weight.

Embedded image (M and n are integers of 3 to 5, m + n is 8 or more, and Z is an alkyl group of 4 or less or a bromine-substituted alkyl group)

The present invention will be described in detail below. The polyphenylene ether used in the present invention is represented by the following general formula (2).

Embedded image [In the formula, m is an integer of 1 to 6, J is a polyphenylene ether chain substantially composed of a unit represented by the following formula (A),

[Chemical 4] (Here, R _{1 to} R ₄ each independently represent a lower alkyl group, an aryl group, a haloalkyl group, a halogen atom or a hydrogen atom.) Q represents hydrogen when m is 1 and when m is 2 or more. Represents a residue of a polyfunctional phenol having 2 to 6 phenolic hydroxyl groups in one molecule and having a polymerization inactive substituent at the ortho and para positions of the phenolic hydroxyl group. ]

In the formula (A) in the general formula (2), examples of the lower alkyl group of R _{1 to} R ₄ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and n.
-Butyl group, isobutyl group, etc., examples of aryl group include phenyl group, etc., examples of haloalkyl group include bromomethyl group, chloromethyl group, etc., examples of halogen atom include bromine, chlorine, etc. Is mentioned.

Representative examples of the Q group in the general formula (2) include the following four kinds of compounds represented by the general formula 5.

Embedded image

(Wherein A ₁ and A ₂ represent the same or different linear alkyl groups having 1 to 4 carbon atoms, X represents an aliphatic hydrocarbon residue and a substituted derivative thereof, an aralkyl group and a substituted thereof). Represents a derivative, oxygen, sulfur, a sulfonyl group, a carbonyl group, Y represents an aliphatic hydrocarbon residue and a substituted derivative thereof, an aromatic hydrocarbon residue and a substituted derivative thereof,
Represents an aralkyl group and a substituted derivative thereof, Z represents oxygen, sulfur, a sulfonyl group, a carbonyl group, and A
_Two phenyl groups linked to 2, A ₂ and X, A ₂ and Y,
All the bonding positions of A ₂ and Z represent the ortho position and the para position of the phenolic hydroxyl group, r is an integer of 0 to 4, and s is an integer of 2 to 6. )

Specific examples include the following formulas 6 to 7.

[Chemical 6]

[0014]

[Chemical 7]

The polyphenylene ether chain represented by J in the general formula (2) contains a unit represented by the following general formula (B) in addition to the unit represented by the general formula (A). May be.

Embedded image

(In the formula, R _{5 to} R ₉ are each independently a hydrogen atom, a halogen atom, a lower alkyl group or an aryl group, and represent a haloalkyl group, and R ₁₀ and R ₁₁ are not hydrogen at the same time.) As an example of the unit of the formula (B),

[Chemical 9] Etc.

Preferred examples of the polyphenylene ether resin of the general formula (2) used in the present invention include poly (2,6-dimethyl-1,4-phenylene ether) obtained by homopolymerization of 2,6-dimethylphenol, and poly (2,6-dimethyl-1,4-phenylene ether). (2,
6-dimethyl-1,4-phenylene ether) styrene graft polymer, 2,6-dimethylphenol and 2,
3,6-trimethylphenol copolymer, 2,6-dimethylphenol and 2-methyl-6-phenylphenol copolymer,

2,6-Dimethylphenol and polyfunctional phenol compound: General formula (3),

[Chemical 10] (Here, m is an integer of 1 to 6, Q represents hydrogen when m is 1, and when m is 2 or more, it has 2 to 6 phenolic hydroxyl groups in one molecule and is phenolic. A polyfunctional polyphenylene ether resin obtained by polymerization in the presence of a polyfunctional phenol residue having a polymerization-inert substituent at the ortho- and para-positions of the hydroxyl group, for example, JP-A-63-301222. The following formulas (A) and (B) as disclosed in JP-A-1-297428.
And a copolymer containing the unit of

[0019]

[Chemical 11] (Here, R _{1 to} R ₄ each independently represent a lower alkyl group, an aryl group, a haloalkyl group, a halogen atom, or a hydrogen atom.)

[0020]

[Chemical 12] (In the formula, R _{5 to} R ₉ are each independently a hydrogen atom, a halogen atom, a lower alkyl group or an aryl group. They represent a haloalkyl group, and R ₁₀ and R ₁₁ are not hydrogen at the same time.)

Regarding the molecular weight of the polyphenylene ether resin described above, the viscosity number ηsp / c measured at 30 ° C. in a chloroform solution of 0.5 g / dl is 0.1 to 1.0.
Those in the range can be used satisfactorily. The component (a) used in the present invention is a polymerizable double bond substantially derived from an acid or an acid anhydride, which is produced by reacting the above polyphenylene ether resin with an unsaturated carboxylic acid or an acid anhydride. It is a reaction product containing no.

The reaction product is probably a mixture of various products having various chemical structures, and the chemical structures thereof are not all elucidated. H. Glans, M .; K. Akkapedd
i, Macromolecules, vol 199
The following chemical structural formula 13 described in 1, 24, 383 to 386 is given as an example.

[0023]

[Chemical 13]

Examples of suitable acids and acid anhydrides include acrylic acid, methacrylic acid, maleic anhydride, fumaric acid,
Examples thereof include itaconic acid, itaconic anhydride, glutaconic anhydride, citraconic anhydride and the like. Particularly, maleic anhydride and fumaric acid are most preferably used. The reaction was carried out by mixing the polyphenylene ether resin with an unsaturated carboxylic acid or acid anhydride 10 times.
It is performed by heating in the temperature range of 0 ° C to 390 ° C. At this time, a radical initiator may coexist. Although both a solution method and a melt mixing method can be used as the reaction method, the melt mixing method using an extruder or the like can be carried out more easily and is suitable for the purpose of the present invention. The proportion of unsaturated carboxylic acid or acid anhydride is 0.01 to 5.0 parts by weight, preferably 0.1 to 3.0 parts by weight, based on 100 parts by weight of the polyphenylene ether resin.

The triallyl isocyanurate and / or triallyl cyanurate used as the component (b) of the present invention is a trifunctional monomer represented by the following structural formula 14.

Embedded image

In carrying out the present invention, triallyl isocyanurate and triallyl cyanurate can be used not only individually but also as a mixture of both at an arbitrary ratio. In the present invention, triallyl isocyanurate and triallyl cyanurate exert an effect as a plasticizer and a crosslinking agent. That is, it improves the flow of resin during pressing and the crosslink density.

The flame retardant used as the component (c) of the present invention is represented by the following general formula (1).

[Chemical 15] (M and n are integers of 3 to 5, m + n is 8 or more, and Z is an alkyl group of 4 or less or a bromine-substituted alkyl group)

In the above formula, m + n is 9 from the viewpoint of the flame retardant effect.
The above is preferable and 10 is the most preferable. Z may have any number of hydrogens replaced by bromine. Any number may be used as long as it has 4 or less carbon atoms, but —CH ₂ CH ₂ — is most preferable. Of the two components (a) and (b) described above, the mixing ratio of the (a) component and the (b) component is the sum of the two.
The component (a) is 98 to 40 parts by weight, the component (b) is 2 to 60 parts by weight, more preferably the component (a) is 95 to 50 parts by weight, and the component (b) is 5 parts by weight based on 00 parts by weight. ~ 5
It is in the range of 0 parts by weight. When the amount of the component (b) is 2 parts by weight or less, improvement in chemical resistance is insufficient, which is not preferable. Conversely, 60
If it exceeds 5 parts by weight, the dielectric properties, flame retardancy, and moisture absorption properties deteriorate, and it becomes a very brittle material after curing, which is not preferable.

The mixing ratio of the component (c) is (a) to (c).
95 to 50 parts by weight of the components (a) + (b) and 5 to 50 parts by weight of the components (c) based on 100 parts by weight of the sum of the components. The component (c) is preferably in the range of 10 to 40 parts by weight, more preferably 10 to 30 parts by weight.
When the amount of the component (c) is less than 5 parts by weight, it is difficult to obtain sufficient flame retardancy, and when it exceeds 50 parts by weight, the fluidity of the resin may be lowered and the adhesive strength may be lowered.

A base material can be added to the curable resin composition of the present invention in order to enhance mechanical strength and dimensional stability. As the substrate used in the present invention, various glass cloths such as roving cloth, cloth, chopped mat, surfacing mat, asbestos cloth, metal fiber cloth and other synthetic or natural inorganic fiber cloth; polyvinyl alcohol fiber, polyester fiber, Woven or non-woven fabric obtained from synthetic fibers such as acrylic fiber, wholly aromatic polyamide fiber, polytetrafluoroethylene fiber; natural fiber cloth such as cotton cloth, linen cloth, felt; carbon fiber cloth; kraft paper, cotton paper, paper-glass blend Natural cellulose-based cloths such as fine paper are used alone or in combination of two or more kinds.

The ratio of the base material in the above curable composite material is 5 based on 100 parts by weight of the curable composite material.
˜90% by weight, more preferably 10 to 80% by weight, still more preferably 20 to 70% by weight. 5% by weight of base material
When it is less, the dimensional stability and strength of the composite material after curing are insufficient, and when the amount of the base material is more than 90% by weight, the dielectric properties and flame retardancy of the composite material are poor, which is not preferable.

Examples of the method for mixing the components (a) to (c) of the present invention include a solution mixing method in which both are uniformly dissolved or dispersed in a solvent, or a melt blending method in which the components are heated by an extruder or the like. Available. As the solvent used for the solution mixing, a halogen-based solvent such as dichloromethane, chloroform and trichloroethylene; an aromatic solvent such as benzene, toluene and xylene; a ketone solvent such as acetone, methyl ethyl ketone and methyl isobutyl ketone; tetrahydrofuran alone or Used in combination of two or more.

The resin composition of the present invention may be molded and cured in advance depending on its use. The molding method is not particularly limited. Usually, a casting method in which the resin composition is dissolved in the above-mentioned solvent and molded into a desired shape, or a heating and melting method in which the resin composition is heated and melted and molded into a desired shape is used. The above-described casting method and heat melting method may be performed independently. Moreover, you may carry out combining each. For example, it is possible to obtain a sheet of the present resin composition by laminating several to several tens of films of the present resin composition prepared by a casting method and heating and melting the film by a heating and melting method, for example, using a press molding machine.

If necessary, a coupling agent can be used in the composite material for the purpose of improving the adhesiveness at the interface between the resin and the substrate. As the coupling agent, silane coupling agents, titanate coupling agents, aluminum-based coupling agents, zircoaluminate coupling agents and the like can be used. The resin composition of the present invention undergoes a crosslinking reaction by means such as heating to be cured as described below, but contains a radical initiator for the purpose of lowering the reaction temperature at that time or accelerating the crosslinking reaction of the unsaturated group. You may use it.

The amount of the radical initiator used in the resin composition of the present invention is 0.1 to 10% by weight, preferably 0.1 to 8% by weight, based on the sum of the components (a) and (b). is there. Representative examples of radical initiators include benzoyl peroxide, cumene hydroperoxide,
2,5-Dimethylhexane-2,5-dihydroperoxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3, di-t-butylperoxide, t-butylcumi Ruperoxide, α, α′-bis (t-butylperoxy-m-isopropyl) benzene, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, dicumyl peroxide, di-t -Butylperoxyisophthalate, t-butylperoxybenzoate, 2,2-bis (t-butylperoxy)
Peroxides such as butane, 2,2-bis (t-butylperoxy) octane, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, di (trimethylsilyl) peroxide, trimethylsilyltriphenylsilylperoxide, etc. Oxides include, but are not limited to.

Although not a peroxide, 2,3-dimethyl-2,3-diphenylbutane can also be used as a radical initiator. However, the initiator used for curing the resin composition is not limited to these examples. The resin composition of the present invention can be used by blending an amount of a filler or an additive within a range that does not impair the original properties for the purpose of imparting desired properties depending on the application. The filler may be fibrous or powdery. As additives, antioxidants,
Examples include heat stabilizers, antistatic agents, plasticizers, pigments, dyes, colorants and the like. For the purpose of further improving flame retardancy, chlorine-based, bromine-based, phosphorus-based flame retardants, Sb ₂ O ₃ and Sb ₂
A flame retardant aid such as O ₅ or NbSbO ₃ .1 / 4H ₂ O may be used in combination. Furthermore, it is also possible to mix one or more kinds of other thermoplastic resins or thermosetting resins.

The multilayer circuit board of the present invention means a circuit board having two or more layers, and there may be one in which a conductor is partially formed on only one side of the insulating board. The circuit board of the present invention will be described in detail with reference to FIG. 1. The circuit board 4 having conductors 2 formed on both sides of an insulating board 1 is laminated with an interlayer insulating material 3 interposed therebetween. Examples of the insulating substrate 1 include a curable polyphenylene ether substrate, an organic insulating material such as paper / phenol, glass / epoxy, glass / polyimide, glass / fluorine, cyanate ester, and BT substrate, or an insulating material such as a ceramic substrate. .

The inter-layer insulating material 3 is formed by dissolving or dispersing the curable polyphenylene ether resin composition constituting the inter-layer insulating material in a solvent and applying it to a circuit board.
Methods such as heating and melting and coating are used, but the method is not necessarily limited to these methods. Moreover, at least the curable polyphenylene ether resin composition of the present invention is used as the interlayer insulating material, and may be used in combination with other insulating materials. As a conductor, gold,
Although silver, nickel, copper, tin, alloys thereof, solder, or the like may be used, copper and its alloys are particularly preferable because of electrical conductivity and economical reasons. The curable polyphenylene ether resin composition of the present invention is also preferably used as an overcoat material formed as necessary.

[0039]

EXAMPLES Hereinafter, the present invention will be described with reference to examples in order to further clarify the present invention, but the scope of the present invention is not limited to these examples. -Flame retardancy A flame retardancy test corresponding to UL-94 standard was conducted. -Withstand voltage test 1000 circuit boards at 80 ℃, 55% relative humidity 1
After leaving it for 000 hours, a voltage of 1 kv is applied between the layers,
The insulation was tested and the percent defective was determined. Reference Example 1 Poly (2,0) having a viscosity number ηsp / c of 0/54 measured at 30 ° C. in a 0.5 g / dl chloroform solution.
100 parts by weight of 6-dimethyl-1,4-phenylene ether), 1.5 parts by weight of maleic anhydride, and 2,5-dimethyl-2,5-di (t-butylperoxy) hexane (manufactured by NOF Corporation, Perhexa) 25B) 1.0 part by weight was dry-blended at room temperature, and then the cylinder temperature was 30.
It was extruded by a twin-screw extruder under the conditions of 0 ° C. and a screw rotation speed of 230 rpm. This reaction product is designated as A.

Reference Example 2 100 parts by weight of poly (2,6-dimethyl-1,4-phenylene ether) having a viscosity number ηsp / c of 0.40 measured by the same method as in Reference Example 1,
After dry blending 1.5 parts by weight of maleic anhydride at room temperature, the cylinder temperature was 300 ° C. and the screw rotation speed was 23.
It was extruded by a twin-screw extruder under the condition of 0 rpm. This reaction product is designated as B.

(Examples 1 and 2) An insulating layer made of cured polyphenylene ether / glass cloth having a copper conductor having a conductor width of 150 μm and a conductor interval of 150 μm was laminated with an interlayer insulating material having the composition shown in Table 1 to form two layers. The results of making the circuit board are summarized in Table 1. (Comparative Examples 1 and 2) Two-layer circuit boards were prepared under the same conditions as in Examples 1 and 2 except that the interlayer insulating material shown in Table 1 was used instead of the interlayer insulating material of the present invention. In the case where the interlayer insulating material of the present invention was not used, the 1 KV withstand voltage failure rate was increased. (Comparative Example 3) When an unmodified polyphenylene ether was used in place of the interlayer insulating material of the present invention to prepare an interlayer insulating material with the resin composition shown in Table 1, the flame retardancy was lowered.

[0042]

[Table 1]

(Note) Peroxide: Perhexin 25B (manufactured by NOF CORPORATION) Flame retardant: SAYTEX 8010 (manufactured by Ethyl Corporation)

Embedded image Flame retardant aid: Antimony pentaoxide (Nippon Concentrate PA Co., Ltd.)
TOX-M)

[0044]

By using the curable polyphenylene ether resin composition of the present invention as an interlayer insulating material of a circuit board, the interlayer insulating layer has a thickness of 200 μm or less, more preferably 100 μm.
Even with a thin film having a thickness of μm or less, it is possible to form a multi-layered substrate having excellent heat-resistant and moisture-proof insulation properties, and a highly reliable thin multi-layered substrate can be obtained. Furthermore, since no decabromodiphenyl ether analogue is used as a flame retardant, it is an excellent material from the viewpoint of environmental protection.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing the structure of a multilayer circuit board according to the present invention.

[Explanation of symbols]

 1 Insulation board 2 Conductor 3 Interlayer insulation 4 Circuit board

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location H05K 1/03 610 7511-4E H05K 1/03 610H // H05K 3/28 3/28 C

Claims (1)

[Claims] 1. A circuit board having conductors formed on both sides of an insulating layer, wherein the interlayer insulating material is (a) a reaction product of polyphenylene ether and an unsaturated carboxylic acid or acid anhydride, and (b) triallyl isocyanate. A curable polyphenylene ether resin composition comprising a neurate and / or triallyl cyanurate, and (c) a flame retardant from a compound represented by the following formula (1), which is the sum of the components (a) and (b): The component (a) is 98 to 40 parts by weight, the component (b) is 2 to 60 parts by weight based on 100 parts by weight, and (a)
To (a) + based on 100 parts by weight of the sum of components (c) +
Component (b) is 95 to 50 parts by weight and component (c) is 5 to 5
A multilayer circuit board, which is a cured product of a curable polyphenylene ether resin composition consisting of 0 parts by weight. Embedded image (M and n are integers of 3 to 5, m + n is 8 or more, and Z is an alkyl group of 4 or less or a bromine-substituted alkyl group)