JP3111389B2 - Low dielectric resin sheet and copper-clad laminate using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition for a laminated board as a material for a double-sided or multilayer printed wiring board used in computers, satellite communications, mobile radio communications equipment, measuring instruments and the like, and to the use of the resin composition. And a copper-clad laminate for printed wiring.

[0002]

2. Description of the Related Art Conventionally, epoxy resins, polyimide resins, and the like have been used as resin materials for double-sided or multilayer printed wiring boards used in computers, measuring instruments, and the like. However, in recent years, with the shift to a highly information-oriented society, the amount of information to be processed has been dramatically increased, and there has been a demand for processing a large amount of information at a higher speed.

Generally, a signal propagation speed V is represented by the following equation.

(Equation 1) (C: speed of light, ε: dielectric constant, K: constant) The smaller the dielectric constant, the higher the speed of computation.
Therefore, for the purpose of improving the signal propagation speed, attempts have been made to lower the dielectric constant of the printed wiring board.

[0004] Conventionally, polytetrafluoroethylene (PTFE), thermosetting polyphenylene oxide (PPO), polyolefin, polybutadiene, and the like have been known as low dielectric constant resin materials. In addition to the above, as a low dielectric constant resin material, there is a cyanate ester resin containing an aromatic or alicyclic compound in a main chain thereof (Japanese Patent Application Laid-Open No. 61-5 / 1986).
00434).

[0005]

SUMMARY OF THE INVENTION However, PTF
E has a large thermal expansion coefficient in the Z-axis direction because it is a thermoplastic resin, and when these are used as a material for a multilayer printed wiring board, there is a problem that dimensional stability and through-hole reliability are inferior. Furthermore, the melting temperature is 250-3
Since the temperature is as high as 50 ° C., there is a problem that workability is inferior, and a complicated processing process called tetra-etching is required even during copper through-hole plating. Further, PPO is an organic solvent resistant to methylene chloride and the like,
Poor solder heat resistance and poor flame resistance, UL-9
There was a problem that it was difficult to obtain a 4VO grade material, and it was not suitable as a material for a multilayer printed wiring board. Furthermore, polyolefins and polybutadienes are essentially unsuitable for high-speed computers because they essentially lack heat resistance and are used at temperatures of 120 ° C. or lower.

Further, the cyanate ester resin comprises:
When heat-treated in the presence of a catalyst such as an organic acid cobalt, a triazine ring structure is obtained, and a cured product having a high crosslinking density can be obtained.The resulting cured product has low moisture absorption, a low dielectric constant, and a low dielectric loss tangent. It is also excellent in heat resistance and dimensional stability, but is inferior in flexibility due to its chemical structure, causing cracks during drilling of laminated boards, reducing the reliability of through-holes, and flame resistance. However, there is a problem that it is difficult to obtain a UL-94VO grade without deteriorating the above-mentioned characteristics, and it is a fact that a satisfactory printed circuit board material is not always obtained.

On the other hand, recently, a substrate in which a porous fluororesin substrate is impregnated with an epoxy resin or a polyimide resin has been proposed as a printed wiring board material [Printed C]
ircuit World Convention I
V, Technical Paper 59-66 (1
987) and JP-A-2-208324]. These are intended to improve workability and dimensional stability by using the thermosetting resin, and to lower the dielectric constant by using a fluororesin. However, since the dielectric constant of an epoxy resin or a general addition type polyimide resin is 3.3 to 4.4, there is a natural limit to lowering the dielectric constant. Introducing a fluorine group to lower the dielectric constant is disadvantageous in terms of cost, and is not preferable as a printed wiring board material.

Accordingly, an object of the present invention is to provide a sheet having low dielectric properties comparable to a conventional printed wiring board made of a composite substrate of glass fiber and fluororesin, and having excellent workability and dimensional stability. And copper-clad laminates.

[0009]

Means for Solving the Problems The present inventors have made intensive studies to achieve the above object, and as a result, have found that a compound having at least two or more cyanate ester groups in a molecule has a specific reactive bromination. By compounding the compound, it has been found that a low dielectric constant resin sheet and a copper-clad laminate for a printed wiring board having improved drillability, dimensional stability, and flame retardancy can be obtained. .

That is, the present invention provides (1) (A) a compound having at least two or more cyanate ester groups in a molecule, and (B) vinyl brominated phenol, a homopolymer, copolymer or vinyl brominated phenol. A low-permittivity resin sheet obtained by impregnating a porous fluororesin sheet with a flame-retardant resin composition comprising a brominated interpolymer or any combination thereof; and (2) laminating the sheet to form a copper foil on the surface. It is a copper-clad laminate characterized by being laminated.

Hereinafter, the present invention will be described in detail. As the compound (A) having at least two cyanate ester groups in the molecule used in the present invention, a compound represented by the general formula [1] or the general formula [2] is used. Can also be used.

[0012]

Embedded image (In the formula, A group containing an aromatic ring or an aromatic ring, B is C ₇ ~
C ₂₀ is a polycyclic alicyclic group, D is a substituent independently containing no active hydrogen group, p, q, and r are each independently an integer of 0 to 3, provided that the sum of p, q, and r is 2 or more. Further, s is each independently an integer from 0 to 4, and x is from 0 to
It is an integer up to 5. )

[0013]

Embedded image (Wherein, R represents an aromatic ring or a group containing an aromatic ring, and m represents 2 to 5
Is an integer up to. )

In the formula (1), A means any group containing an aromatic ring, and specifically, a phenylene group, a naphthylene group, an anthrylene group, a biphenylene group, a binaphthylene group, or an alkylene group. It is a group containing two or more bonded aromatic rings, among which a phenylene group and a naphthylene group are preferable, and a phenylene group is particularly preferable.

In the formula [1], B represents C _{7 to} C
₂₀ represents a polycyclic alicyclic group, which means an alicyclic group containing two or more rings, wherein the polycyclic alicyclic group contains one or more double bonds or triple bonds. You may. Specific examples are listed below. Among them, (a),
(B), (c), (d), and (e) are preferable, and (a) is particularly preferable.

[0016]

Embedded image (Where Y is CH ₂ , S, S = O, O = S = O,
D 'is an alkyl group of _C 1 -C _5. )

In the formula [1], D is each independently a substituent containing no active hydrogen group, and a substituent containing an active hydrogen atom is excluded. Here, the active hydrogen atom means a hydrogen atom bonded to an oxygen, sulfur, or nitrogen atom. Specific examples thereof include a hydrogen atom, a C ₁ -C ₁₀ alkyl group,
Alkenyl group of ₁ -C _10, alkynyl of C 1 _{C 5,}
A C ₁ -C ₅ alkoxy group, a nitro group, a carboxyl group, a halogen atom, etc., among which a hydrogen atom, C ₁
Alkyl -C _3, or a halogen atom, a hydrogen atom, the bromine atom are particularly preferred.

In the formula [1], s is an integer from 0 to 4, preferably 0 to 1, and particularly preferably 0. Further, p, q, and r are each independently an integer of 0 to 3, and among them, 1 is particularly preferable. Where p,
The sum of q and r is set to be 2 or more. Further, while x is an integer from 0 to 5, the cyanate ester resin of the formula [1] is found as a mixture of compounds where x is from 0 to 5.

A preferred specific example of the cyanate ester resin represented by the formula [1] is represented by the following formula, which is available as QUATREX-7187 (manufactured by Dow Chemical Company).

[0020]

Embedded image

In the formula (2), R is an aromatic ring or a group containing an aromatic ring, m is an integer of 2 to 5, and specific examples thereof are 1,3-dicyanatobenzene,
4-dicyanatobenzene, 1,3,5-tricyanatobenzene, 1,3-, 1,4-, 1,6-, 1,8
-, 2,6- or 2,7-dicyanatonaphthalene, 1,3,6-tricyanatonaphthalene, 4,4 '
-Dicyanatobiphenyl, bis (4-dicyanatophenyl) methane, 2,2-bis (4-cyanatophenyl) propane, 2,2-bis (3,5-dichloro-4-
Cyanatephenyl) propane, 2,2-bis (3,5
-Dibromo-4-cyanatophenyl) propane, bis (4-cyanatophenyl) ether, bis (4-cyanatophenyl) thioether, bis (4-cyanatophenyl) sulfone, tris (4-cyanatophenyl) phosphite , Tris (4-cyanatophenyl)
Phosphates, and cyanate esters obtained by reacting novolaks with cyanogen halides, and the like,
Among them, bis (4-dicyanatophenyl) methane,
2,2-bis (4-cyanatophenyl) propane is particularly preferred.

The (B) vinyl brominated phenol, vinyl brominated phenol homopolymer, copolymer, or brominated interpolymer used in the present invention or any combination thereof is represented by the general formula [3]:

Embedded image (Wherein n represents an integer of 1 or 2), a monomer of vinyl brominated phenol, a homopolymer of formula [3], styrene, o-methylstyrene, p-methylstyrene, P- Copolymers or interpolymers with chlorostyrene, P-methoxystyrene, methyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, N-phenylmaleimide, divinylbenzene, and the like.

These components (B) include, in addition to a bromine atom,
It is characterized by having a phenolic hydroxyl group having a cyanate ester group and a moderately reactive group. By blending the component (B) of the present invention with the component (A), dielectric properties, heat resistance, The present invention can provide a resin composition having excellent dimensional stability and flame retardancy.

The mixing ratio of the above components (A) and (B) is such that the bromine content of the composition is 5 to 30% by weight, more preferably 1 to 3, based on the combined weight of the components (A) and (B).
It is preferable that the content be 0 to 20% by weight. If the bromine content is less than 5% by weight, a flame-retardant UL94VO cannot be obtained. On the other hand, when the bromine content exceeds 30% by weight, the dielectric constant is increased and the heat resistance is impaired, which is not preferable.

Examples of the porous fluororesin sheet used in the present invention include ethylene tetrafluoride, ethylene tetrafluoride / perfluorovinyl ether copolymer resin, ethylene tetrafluoride / propylene hexafluoro copolymer resin, It is a porous sheet of a fluororesin such as a fluoroethylene / ethylene copolymer resin and an ethylene trifluorochloride resin, and among them, a porous sheet of a tetrafluoroethylene resin is preferable. The porous sheet is a continuous porous sheet having properties of a pore size of 0.1 to 15 μm, a porosity of 25 to 85%, and a thickness of 0.05 to 1.0 mm.
15 μm, porosity 50-85%, thickness 0.1-0.3 m
Those having the property of m are preferred. At this time, the pore size is 0.1 μm
If it is less than 3, the resin composition may be difficult to sufficiently fill the pores during lamination and may remain as voids. In addition, the hole diameter 1
If the sheet exceeds 5 μm, it becomes difficult to manufacture the sheet itself, and it is difficult to obtain a sheet of stable quality. When the thickness is less than 0.05 mm, the withstand voltage is lacking, and when the thickness exceeds 1.0 mm, it is not practical for forming a multilayer.

Next, a method for producing a low dielectric resin sheet for a printed wiring board using the flame-retardant resin composition of the present invention and a copper-clad laminate using the sheet will be described.

In making a low dielectric constant resin sheet,
First, a varnish is prepared by dissolving the components (A) and (B) and the reaction catalyst in an organic solvent.
Next, this varnish is impregnated in a porous fluororesin sheet and dried by heating. At this time, the amount of the varnish impregnated into the porous fluororesin sheet was determined as follows: the ratio of the resin solid content [the sum of the components (A) and (B)] to the total weight after drying was 3%.
It is preferably set to be 0 to 70% by weight, preferably 40 to 60%. The heating and drying conditions when manufacturing the resin sheet are affected by the amount of the reaction catalyst added,
For example, when the heating temperature is 150 ° C., the heating time is 3
By setting the time to about 10 minutes, a desired stroke gel time of the resin sheet can be obtained.

Examples of the reaction catalyst include organic acid metal salts such as cobalt naphthenate, cobalt octylate, zinc octylate, manganese octylate, potassium acetate, sodium acetate, sodium cyanate, sodium isocyanate, sodium boride, etc. Metal salts, tertiary amines such as pyridine, imidazoles, and triethylamine; Lewis acids such as aluminum chloride, ferric chloride, and zinc chloride; and the like. In particular, cobalt naphthenate, cobalt octylate, and octyl Organic acid metal salts such as manganese acid are preferred. The addition amount of the reaction catalyst is not particularly limited. For example, in the case of using an organic acid cobalt, the weight of the cyanate ester resin represented by the component (A) is based on the desired gel time of the resin sheet. It is blended in the range of 10 to 500 ppm by weight of the metal.

The organic solvent is not particularly limited as long as it dissolves the compounds of the components (A) and (B) and does not adversely affect the reaction. Examples thereof include ketones such as acetone and methyl ethyl ketone. , Dimethylformamide,
Polar amide solvents such as dimethylacetamide and N-methylpyrrolidone are used, and these can be used alone or as a mixture. The amount of the organic solvent to be added is such that the solid content concentration in the varnish is 30 to 70% by weight, preferably 40 to 70%.
In general, the amount is adjusted to be 60% by weight.

Then, a plurality of the resin sheets prepared as described above are laminated, and further, copper foil is laminated on both upper and lower surfaces, and this is heated and pressed to form the components (A) and (B) in the resin sheet. (2) A copper-clad laminate in which copper foil is laminated and adhered to both surfaces of an insulating substrate formed by polymerization and curing of a component can be produced. In addition, if necessary, in order to reinforce the laminate, a flame-retardant resin composition comprising the components (A) and (B) may be interposed between resin sheets on a woven or non-woven fabric of inorganic fibers or organic fibers. It is also possible to laminate with a normal prep league impregnated with objects. The molding conditions at this time are as follows: a heating temperature of 170 to 230 ° C. and a pressure of 25 to 50 k.
In general, g / cm ² and time are set to about 1 to 2 hours. In the case where after-curing is performed at 220 to 230 ° C after molding, a molding temperature of 170 to 180 ° C is sufficient.

Further, in order to produce a multilayer printed wiring board, an inner layer board is produced by forming a circuit by etching a copper foil of a copper-clad laminate produced by the above method, and then forming an inner layer. By laying the plates via a plurality of the above-mentioned resin sheets or prepregs, laying a copper foil on the outermost layer, and heat-forming this, a shield plate as a multilayer printed board can be produced. The thus-obtained double-sided copper-clad laminate and shield plate can be formed into a printed wiring board by using a known method described below.

[0032]

The present invention will be described below in detail with reference to examples.

Embodiment 1 The component (A) has the general formula [1]
Cyanate ester resin QUATREX 7 represented by
187 (manufactured by Dow Chemical Co., Ltd.), 75 g of vinyl bromphenol phenol polymer (Marcalinker M as component (B))
B, manufactured by Maruzen Petrochemical Co., Ltd., molecular weight 6,000-7000) 2
50 g was dissolved in 67 g of a 1: 1 mixed solvent of methyl ethyl ketone (MEK) and dimethylformamide (DMF) to obtain a resin solution. Then, a varnish having a resin content of 50% by weight was prepared by adding cobalt octylate as a reaction catalyst to Co at a weight ratio of 100 ppm to the cyanate ester resin. This varnish was prepared. This varnish is 100 μm in thickness and 3 μm in average pore size.
m, and impregnated into a porous sheet of tetrafluoroethylene resin having a porosity of 80% so that the resin content becomes 50% by weight.
By heating at 0 ° C. for 5 minutes, a low dielectric resin sheet was prepared. Next, three resin sheets were stacked, and a copper foil having a thickness of 18 μm was stacked on both surfaces thereof.
A double-sided copper-clad laminate was obtained by heating and pressing for 60 minutes at a temperature of 40 ° C. and a pressure of 40 kg / cm ² .

Embodiment 2 FIG. As the component (B), vinyl bromophenol, styrene copolymer (molar composition ratio 8: 2,
A copper-clad laminate was obtained in the same manner as in Example 1 except that 30 g of a polymer (molecular weight: 10,000) was used.

Embodiment 3 FIG. (B) As components, 27 g of vinylbromophenol monomer, 3 g of divinylbenzene,
A copper-clad laminate was obtained in the same manner as in Example 1, except that a mixed solution of 0.5 g of cumene peroxide was used.

Embodiment 4 FIG. (A) As a component, QUATR
A copper-clad laminate was obtained in the same manner as in Example 1, except that 50 g of EX 7187 and 25 g of 2,2-bis (4-cyanatophenyl) propane were used.

Embodiment 5 FIG. (A) As a component, QUATR
A copper-clad laminate was obtained in the same manner as in Example 1, except that 60 g of EX 7187 and 15 g of 2,2-bis (4-cyanatophenyl) methane were used.

Comparative Example 1 A copper-clad laminate was obtained in the same manner as in Example 1, except that 98 g of tetrabromobisphenol A diglycidyl ether, 1 g of dicyandiamide and 1 g of 2-ethylimidazole were used as the resin composition.

Comparative Example 2 As a resin composition, 4,4′-
Kellimide 6 obtained by reacting diaminodiphenylmethane with N, N'-4,4'-diphenylmethanebismaleimide
A copper-clad laminate was obtained in the same manner as in Example 1 except that 100 g of 01 (manufactured by Nippon Polyimide) was used.

The laminate thus obtained was evaluated as a laminate by the method described below.

(1) Dielectric constant and dielectric loss tangent According to JIS C-6481, the value at 1 MHz was measured by using an LP impedance analyzer 4194A (manufactured by Yokogawa Hewlett-Packard Co., Ltd.).

(2) Peel strength A sample of a predetermined size is prepared according to JIS C-6481, and a precision universal material testing machine type 2020 (manufactured by Intesco Corporation)
It measured using.

(3) Insulation Resistance According to IPC-B25, a 375 μm-wide comb-shaped electrode was prepared, and a vibrating lead electrometer T was used.
Using R-84M (manufactured by Takeda Riken Co., Ltd.), the insulation resistance was measured when DC 500 V was applied.

(4) Flame retardancy Evaluation was made by the vertical method according to the UL-94 standard.

(5) Heat resistance The laminate was subjected to a pressure cooker treatment (121 ° C., 2 at
m for 3 hours), immersed in a solder bath at 260 ° C. for 60 seconds, and evaluated by visual observation of appearance properties. ○: No abnormality ×: Whitening phenomenon occurred

The results obtained are shown in Table 1.

[0047]

[Table 1]

[0048]

As is clear from the above description, the low dielectric constant resin sheet according to the present invention has excellent low dielectric properties, adhesive strength to copper foil, heat resistance, and flame resistance. It can be suitably used as a printed wiring board material for satellite communication equipment, high-speed computers, and the like.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI C08L 79/00 C08L 79/00 Z H01B 3/42 H01B 3/42 E 3/48 3/48 5/02 5/02 A H05K 1/03 610 H05K 1/03 610M 610T (56) References JP-A-50-116595 (JP, A) JP-A-57-137 (JP, A) JP-A-4-300952 (JP, A) Hei 4-351625 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01B 3/30 H01B 3/42 H01B 3/48 B32B 7/10 B32B 15/08 C08J 5/24 C08J 9/42 C08L 79/00 H01B 5/02 H05K 1/03 610

Claims (2)

(57) [Claims] 1. A compound having (A) a compound having at least two or more cyanate ester groups in a molecule, (B) vinyl brominated phenol, a homopolymer of vinyl brominated phenol,
A low dielectric constant resin sheet comprising a porous fluororesin sheet impregnated with a flame-retardant resin composition comprising a copolymer or an interpolymer, or any combination thereof. 2. A copper-clad laminate obtained by laminating the low dielectric constant resin sheets according to claim 1 and laminating a copper foil on a surface thereof.