JPH07118413A - Production of prepreg, laminated board using the same, and printed wiring board using the laminated board - Google Patents

Abstract

PURPOSE:To obtain a prepreg excellent in low hygroscopicity and high heat resistance, useful for laminated boards and printed wiring boards of low thermal expansion by impregnating aramid paper with an epoxy resin varnish of specific composition followed by drying to effect semicuring. CONSTITUTION:The objective prepreg can be obtained by impregnating (A) an epoxy resin varnish comprising (1) pref. 100 pts.wt. of a compound having in one molecule two or more epoxy groups (e.g. bisphenol A-type epoxy resin, phenol-novolak type epoxy resin), (2) pref. 5-50 pts.wt. of a compound having in one molecule two or more epoxy groups and naphthalene ring, fluorene or dicyclopentadiene (e.g. a compound of formula I, II, etc.) and (3) a curing agent in (B) aramid paper followed by drying at 120-180 deg.C to effect semicuring. These prepregs are superposedly subjected to hot pressing at 140-200 deg.C) and 10-50kg/cm<2> to completely curing the resin varnish, thus affording the second objective laminated boards.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for producing a prepreg in which an aramid paper is impregnated with an epoxy resin,
The present invention relates to a laminated board using the prepreg and a printed wiring board using the laminated board.

[0002]

2. Description of the Related Art Conventionally, for a laminated board processed into a printed wiring board or the like, a prepreg is prepared by impregnating a base material such as glass cloth with a resin varnish such as epoxy resin and drying the prepreg. It is known that a required number of sheets are piled up, and if necessary, a metal foil such as a copper foil is piled up on one side or both sides of the metal foil, and this is heat-pressed and molded.

With respect to such a laminated board, as the tendency of high density mounting and high integration of the printed wiring board increases,
Improvements in various properties such as low dielectric constant and processability have been demanded. Therefore, in response to this problem, a laminated board using aramid paper as a base material instead of the glass fiber base material has been proposed.

However, due to the large thermal expansion of the laminated plate, a shift occurs between the inner layer circuits or between the inner layer circuit and the outer layer circuit, resulting in poor conduction between the through holes and the inner and outer layer circuits, and moisture absorption. There was a problem that the rate was high and the durability was poor.

[0005]

SUMMARY OF THE INVENTION Therefore, the present invention reduces the thermal expansion of the laminated plate and eliminates the deviation between the inner layer circuits or between the inner layer circuit and the outer layer circuit, and as a result, the through hole and the inner and outer layer circuits. Disclosed is a method for producing a prepreg, which is capable of preventing poor continuity with a space, and can obtain high heat resistance with low hygroscopicity, a laminated board using the prepreg, and a printed wiring board using the laminated board. It is in.

[0006]

The method for producing a prepreg according to claim 1 of the present invention comprises a compound (1) having two or more epoxy groups in one molecule, a naphthalene ring, fluorene or dicyclohexene in one molecule. Two pentadiene and epoxy groups
The invention is characterized in that an aramid paper is impregnated with an epoxy resin varnish containing at least one compound (2) and a curing agent, and is dried and semi-cured.

A laminated board using the prepreg according to claim 3 of the present invention is characterized by using the prepreg of claim 1 to obtain a laminated board in which a resin varnish is completely cured.

Further, a printed wiring board using the laminated board according to claim 4 of the present invention is the same as the printed wiring board according to claim 3,
It is a produced printed wiring board.

[0009]

According to the method for producing a prepreg according to claim 1 of the present invention, a compound (1) having two or more epoxy groups in one molecule, a naphthalene ring, fluorene or dicyclopentadiene and an epoxy group in one molecule. Using prepreg obtained by impregnating aramid paper with epoxy resin varnish containing compound (2) having two or more and a curing agent, drying and semi-curing to reduce thermal expansion of the laminated board, Alternatively, it is possible to eliminate the gap between the inner layer circuit and the outer layer circuit, realize low moisture absorption and high heat resistance, and enhance the reliability of the printed wiring board.

According to the laminated plate using the prepreg according to claim 3 of the present invention, a laminated plate in which the resin varnish is completely cured is obtained by using the prepreg according to claim 1. The thermal expansion of the plate can be reduced.

Further, according to the printed wiring board using the laminated board of the fourth aspect of the present invention, since the printed wiring board is produced by using the laminated board of the third aspect, the printed wiring board is as described above. It is possible to eliminate the gap between the inner layer circuits or between the inner layer circuit and the outer layer circuit, and as a result, it is possible to prevent the conduction failure between the through hole and the inner and outer layer circuits, and to improve the reliability of the printed wiring board. .

The method of manufacturing the prepreg of the present invention will be described below. Explaining the components constituting this prepreg, first, for the compound (1) having two or more epoxy groups in one molecule, any compound which has been conventionally used as a resin component of a laminate can be used, For example, as these compounds (1), bisphenol A type epoxy resin, bisphenol F type epoxy resin,
Bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A type novolac type epoxy resin, 2,
Glycidyl etherified resin of 6-xylenol dimer,
Bisphenol F type novolac type epoxy resin, isocyanurate type epoxy resin, hydantoin type epoxy resin, polyfunctional type epoxy resin such as trifunctional type epoxy resin and tetrafunctional type epoxy resin, glycidylamine type epoxy resin, diaminophenyl ether Examples thereof include glycidylated epoxy resin, alicyclic epoxy resin, and brominated flame-retardant resins thereof. These things are
They can be used alone or in combination of several kinds.

As the compound (2), a compound having a naphthalene ring, fluorene or dicyclopentadiene and having two or more epoxy groups is used, and an epoxy resin of the same type as the compound (1) is used. . These compounds may be used alone or in combination of several kinds. Specifically, compounds represented by the following (Chemical formula 1) to (Chemical formula 5) are exemplified, and those having a naphthalene ring are:
The following (Chemical formula 1), (Chemical formula 2) and (Chemical formula 3), and those having fluorene are the following (Chemical formula 4). Moreover, what has dicyclopentadiene is shown in the following (Chemical formula 5).

[0014]

[Chemical 1]

[0015]

[Chemical 2]

[0016]

[Chemical 3]

[0017]

[Chemical 4]

[0018]

[Chemical 5]

The compounding ratio of the compound (2) to the compound (1) is 5 to 50 parts, preferably 10 to 30 parts, relative to 100 parts by weight of compound (1) (hereinafter abbreviated as "part"). is there. If it is less than 5 parts, there is no effect of reducing the thermal expansion coefficient of the molded product,
If it exceeds 50 parts, the mechanical properties tend to deteriorate, which is not preferable.

As the curing agent, generally used dicyandiamide (Dicy), amino compound, phenol novolac, cresol novolac, etc. can be used, and these can be used alone or in combination of several kinds. You can also

Further, when a compound having two or more phenolic OH groups in one molecule is used in combination with such a curing agent system, the heat resistance such as Tg is slightly lowered, but an extremely low hygroscopic prepreg and A laminated board can be obtained. Examples of this compound include bisphenol A, bisphenol F, bisphenol S, and polyvinylphenol.
, Low molecular weight compounds such as β-naphthol, phenol novolac resin, cresol novolac resin, bisphenol
Examples thereof include a type A novolac resin, an alkylphenol novolac resin, a triphenylmethane type trifunctional novolac resin synthesized from phenol and hydroxybenzaldehyde, and bromides thereof. The resinous compound or resin may be used in combination of several kinds.

Incidentally, these curing agents are preliminarily methyl ethyl ketone (MEK), acetone, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, methanol, ethanol, toluene, xylene, dimethylformamide (DMF), dimethylacetamide (DMAc), N-. Methylpyrrolidone (NM
P), methyl cellosolve (MC), dioxane and the like used for forming the resin varnish can be used alone or by dissolving them in a mixed solvent. In this case, 10 to 30 at 150 to 150 ° C
Preliminary heating reaction for 60 minutes is preferable from the viewpoint of making the curing agent uniform, preventing the precipitation of dicyandiamide (Dicy), and improving the storage stability of the resin.

In addition, the curing accelerator may be selected from known ones such as imidazole compounds, tertiary amines and boron trifluoride complex salts.

The resin varnish prepared by blending each of the above components is mainly used in a liquid form by coating it on aramid paper, impregnating it and then drying it. Therefore, it is usually diluted with the above solvent before use. Solvents for this include methyl ethyl ketone (MEK), acetone, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, methanol, ethanol, toluene, xylene, dimethylformamide (DMF), dimethylacetamide (DMAc), N-methylpyrrolidone (NMP). , Methyl cellosolve (MC), dioxane and the like can be used, and a plurality of these may be used in combination. The dilution ratio is preferably 50% to 80% of solid content. A resin varnish varnished with a solvent is impregnated into aramid paper and dried in a dryer at 120 to 180 ° C. for about 3 to 10 minutes to obtain a semi-cured (B-stage) prepreg. .

The aramid paper used here is a strand obtained by bundling an ultrafine filament obtained by melting aramid with a sizing agent to form a short fiber, and the short fiber is formed into a thin layer by a dry method or a wet method. To be

The prepreg obtained according to the present invention has 14
0 to 200 DEG ° C., to manufacture a laminate by applying heat and pressure in the range of 10 to 50 kg / cm ^2, also used to produce the printed wiring metal foil-clad laminate by applying heat and pressure with a metal foil To be As the metal foil in this case, an appropriate material such as copper, aluminum, stainless steel, or the like is used, and the metal foil can be laminated and formed with a required number of prepregs.
Moreover, when manufacturing a multilayer board, the surface temperature of the inner layer copper foil is generally chemically treated to make copper oxide (blackening treatment) with epoxy resin materials, so the molding temperature is 150-180. It is preferably set to ° C. If the molding temperature is less than 150 ° C, curing will be insufficient and the required heat resistance will not be obtained, and the adhesive strength between the prepreg and the inner layer copper foil will be insufficient. Also, if the temperature exceeds 180 ° C., the uneven surface of the copper oxide disappears and the adhesive strength between the prepreg and the inner layer copper foil becomes insufficient.

The obtained laminated plate may be drilled, subjected to through-hole plating, and then patterned to obtain a printed wiring board.

[0028]

Example 1 As a compound (1) having two or more epoxy groups in one molecule, a brominated bisphenol A type epoxy resin (epoxy equivalent 500 g / equivalent, manufactured by Tohto Kasei Co., Ltd .; trade name YDB)
-500) and diluted with methyl ethyl ketone (MEK) to a solid content concentration of 75 wt%, 117 g
Manufactured by Tohto Kasei Co., Ltd .; YDCN-220, trade name, was diluted with MEK to a solid content concentration of 70 wt%, and 18 g were mixed together and mixed. As a compound (2) having two or more naphthalene rings, fluorene or dicyclopentadiene and epoxy groups in one molecule, a naphthalene type epoxy resin (epoxy equivalent 220 g / equivalent, manufactured by Dainippon Ink and Chemicals; trade name HP-4032H ) Was used. A resin varnish was prepared by mixing 2.8 g of dicyandiamide (Dicy) as a curing agent and 0.10 g of 2-ethyl-4-methylimidazole (2E4MZ) as a curing accelerator, to prepare a resin varnish. Mount: Density 72g / m ² , made by DuPont) with resin content
It was impregnated so as to have a concentration of 52 wt% ± 2 wt% and dried in a drier to prepare a prepreg having a gel time of 170 seconds at 330 seconds.

Next, eight prepregs having a resin content of 52 wt% were stacked, copper foil of 35 μm was arranged on both sides of the prepreg, and a release film and a metal plate were arranged on the outer side of the prepreg.
Insert between hot plates at 0 to 135 ℃ and apply initial pressure of 10kg / cm
² low pressure, and then 40 kg / cm ² pressurization of the second stage, the heating plate temperature was raised to 170 ° C. and heated pressure lamination to obtain a copper-clad laminate having a thickness of 0.8 mm.

Example 2 As an epoxy resin of the compound (1) having two or more epoxy groups in one molecule, a brominated trifunctional epoxy resin (epoxy equivalent 390 g / equivalent, manufactured by Mitsui Petrochemical Co., Ltd .; trade name VF- 771 g of which the solid content concentration was 80 wt% by diluting 2801) with methyl ethyl ketone (MEK).
And trifunctional epoxy resin (epoxy equivalent 210 g / equivalent, Mitsui Petrochemical Co., Ltd .; trade name VG-3101) are diluted with methyl ethyl ketone (MEK) to give a solid content concentration of 80.
24 g of wt%, manufactured by Tohto Kasei Co .; trade name Y
19g of DB-400 was used together and mixed. As a compound (2) having two or more naphthalene rings, fluorene or dicyclopentadiene and epoxy groups in one molecule, a naphthalene type epoxy resin (epoxy equivalent 220 g / equivalent, manufactured by Dainippon Ink and Chemicals; trade name HP-4032)
15 g of H) was used. 2.5 g of dicyandiamide as a curing agent and tetraethyldiamidediphenylmethane (
Made by Nippon Kayaku Co., Ltd .; trade name C-300) (8.0 g) is used, and 2-ethyl-4-methylimidazole (2E4) is used as a curing accelerator.
Example 1 was repeated except that 0.11 g of MZ) was dissolved and mixed and used as a resin varnish.

Example 3 As the epoxy resin of the compound (1) having two or more epoxy groups in one molecule, a brominated trifunctional epoxy resin (epoxy equivalent 390 g / equivalent, manufactured by Mitsui Petrochemical Co., Ltd .; trade name VF- 771 g of which the solid content concentration was 80 wt% by diluting 2801) with methyl ethyl ketone (MEK).
And trifunctional epoxy resin (epoxy equivalent 210 g / equivalent, Mitsui Petrochemical Co., Ltd .; trade name VG-3101) are diluted with methyl ethyl ketone (MEK) to give a solid content concentration of 80.
24 g of what was made into wt% and brominated bisphenol A
19 g of a type epoxy resin (epoxy equivalent: 400 g / equivalent, manufactured by Tohto Kasei Co .; trade name YDB-400) was used together and mixed. As a compound (2) having two or more naphthalene rings, fluorene or dicyclopentadiene and epoxy groups in one molecule, a naphthalene type epoxy resin (epoxy equivalent 220 g / equivalent, manufactured by Dainippon Ink and Chemicals; trade name HP-4032H ) Was used. 2.7 g of dicyandiamide as a curing agent and tetraethyldiamidediphenylmethane (manufactured by Nippon Kayaku Co., Ltd .; trade name C-300)
The same procedure as in Example 1 was carried out except that 8.5 g was used and a solution of 0.09 g of 2-ethyl-4-methylimidazole (2E4MZ) as a curing accelerator was mixed and used as a resin varnish.

Comparative Example 1 The procedure of Example 1 was repeated except that the naphthalene ring, fluorene or dicyclopentadiene and the compound (2) having two or more epoxy groups in one molecule of Example were not used.

Comparative Example 2 The procedure of Example 2 was repeated except that the naphthalene ring, fluorene or dicyclopentadiene and the compound (2) having two or more epoxy groups in one molecule of Example were not used.

Comparative Example 3 The procedure of Example 1 was repeated except that the resin varnish of Example 1 was used and a glass cloth (216L, manufactured by Asahi Schwebel) was impregnated with the resin varnish instead of the aramid paper.

The following Table 1 shows the above Examples 1 to 3 and Comparative Example 1
The formulations of the resin varnishes of ~ 3 are summarized. The description (MEK75%) shown in Table 1 indicates that the solid content is 75 wt% when diluted with MEK, and (MEK80
%) Indicates that the solid content is 80 wt% when diluted with MEK.

[0036]

[Table 1]

The results of the characteristic evaluations of Examples 1 to 3 and Comparative Examples 1 to 3 are shown in Table 2. Thermal expansion coefficient is IPC-TM
The thermal expansion coefficient up to the glass transition point was determined by the thermodynamic analysis method of -650, 2.4.24.

Moisture absorption rate and heat resistance are JIS C64
Based on 81, a test piece of a laminated plate of 50 mm ± 1 mm × 50 mm ± 1 mm is prepared, and each value is measured.

Through-hole reliability is MIL-STD-202-107E
According to the above, a test piece in which a test pattern was plated with copper through holes was created, and a thermal shock of -65 ° C. to 125 ° C. was given, and the number of cycles until disconnection was counted. However, the measurement conditions are: total number of holes: 200 holes, hole diameter: 0.9 mmφ, land diameter: 1.3
mmφ, line width: 0.2 mm, drilling conditions: 60,000 rpm, 50 μm
/ rev.

From Table 2, in Examples 1 to 3 and Comparative Examples 1 and 2, there is a marked difference in the number of cycles of the characteristics showing the reliability of the through-hole connecting portion, because one molecule of the epoxy resin which is the main compounding component is present. This is because the compound (2) having a naphthalene ring, fluorene or dicyclopentadiene and two or more epoxy groups therein is used in Examples, but not used in Comparative Examples. When using the resin of the example, the laminate obtained by using the prepreg of the present invention, the thermal expansion of the laminate is reduced, between the inner layer circuit or the inner layer circuit of the printed wiring board using this laminate It was possible to eliminate the gap between the outer layer circuits, and as a result, it was possible to prevent defective conduction between the through hole and the inner and outer layer circuits. Furthermore, the hygroscopicity and heat resistance of the printed wiring board, especially the improvement of through-hole reliability were observed.

The general characteristics shown in Table 2 when the glass cloth was used as the base material of Comparative Example 3 were the same as those of the example. However, as shown in Table 3, compared with Comparative Example 3, electrical properties such as relative permittivity and dielectric loss tangent of Example 1 were improved, surface roughness was reduced, and an excellent appearance could be obtained. .

The measurement of relative permittivity and dielectric loss tangent is JIS standard C
Create test pieces based on 6481, temperature 20 ℃, humidity 6
Leave it at 5% for 96 hours, and then perform water absorption treatment at a temperature of 23 ° C.
The measurement was performed for 24 hours.

The surface roughness is measured by a surface roughness measuring instrument (SURFC).
OM550A: manufactured by Tokyo Seimitsu Co., Ltd.).

[0044]

[Table 2]

[0045]

[Table 3]

[0046]

According to the method for producing a prepreg of the present invention, the laminated board using the prepreg, and the printed wiring board using the laminated board, when aramid paper is used as the base material, the thermal expansion of the laminated board is reduced. It is possible to prevent a deviation between the inner layer circuits or between the inner layer circuit and the outer layer circuit, and as a result, it is possible to prevent defective conduction between the through hole and the inner and outer layer circuits. Furthermore, low hygroscopicity and high heat resistance were realized, and reliability could be significantly improved.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location // C08L 63:00 (72) Inventor Tomoyuki Fujiki 1048 Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Works Co., Ltd. In the company

Claims (4)

[Claims] 1. A compound (1) having two or more epoxy groups in one molecule, a naphthalene ring, fluorene or dicyclopentadiene and a compound (2) having two or more epoxy groups in one molecule, and a curing agent. A method for producing a prepreg, which comprises impregnating an aramid paper with an epoxy resin varnish, drying and semi-curing. 2. The compounding ratio of the compound (2) to the compound (1) is 5 to 50 relative to 100 parts by weight of the compound (1).
2. The method for producing a prepreg according to claim 1, wherein the prepreg is part by weight. 3. A laminated board in which a resin varnish is completely cured using the prepreg according to claim 1. 4. A printed wiring board produced by using the laminated board according to claim 3.