JPH09326557A - Manufacture of multilayer printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a multilayer printed wiring board excellent in laminate characteristics without subjecting an inner circuit to a blackening treatment by a method wherein undercoating agent and copper are enhanced in adhesion to each other. SOLUTION: Single-sided or double-sided copper-clad laminates where a circuit is provided respectively and prepregs formed of base material impregnated with thermosetting resin and dried out are laminated overlapping each other for the manufacture of a multilayer printed wiring board, wherein two functional group-terminated straight linkage high-molecular epoxy resin (1) whose average epoxy equivalent weight is 450 to 6000 and undercoat agent (2) which contains aromatic polyamine possessed of ether linkages or ether linkages and sulfone linkages as integral components and serves as hardening agent are applied onto the circuits of the copper-clad laminates, and then the copper-clad laminates and prepregs formed of base material impregnated with epoxy resin and dried out are laminated overlapping each other and formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a multilayer printed wiring board which does not require an oxidation treatment (black treatment).

[0002]

2. Description of the Related Art As a conventional manufacturing method of a multilayer printed wiring board, generally, the circuit surface of a circuit-processed copper-clad laminate laminated on an inner layer is subjected to an oxidation treatment called so-called black treatment, After roughening the circuit surface, superimpose one or more prepregs on which a thermosetting resin has been applied / impregnated / dried on the base material, and then superimpose a metal foil on it.
Pressing was performed using a heated hot platen. The purpose of the black treatment is to obtain good adhesion to the prepreg. Since the inner layer circuit not subjected to the black treatment and the prepreg have little adhesion, the black treatment is an essential technology. However, this technology is an application of the oxidation phenomenon caused by the chemical treatment of the copper foil of the inner layer circuit board, and basically,
It is very difficult to control the process, and large capital investment and running cost are required. Further, it has been pointed out that copper oxide has a weak acid resistance and a low physical strength, so that problems are likely to occur during multilayer molding, drilling or through-hole plating.

As a method for producing a multilayer printed wiring board in which a resin layer is formed on the surface of a circuit-processed copper clad laminate as shown in the present invention, JP-A-53-132772 and JP-A-60-62194 are disclosed. JP-A-63-108796
In each of the technologies, the goal is to improve the withstand voltage property, the halo resistance, the heat dissipation property, and the insulating layer thickness by reducing voids during molding. However, the present invention has a completely different purpose.

[0004]

The present invention relates to a multilayer printed wiring board which does not require black treatment. The present inventors have made extensive studies on the composition of the undercoating agent in order to solve the problem of the moldability of the multilayer printed wiring board, and further the problem of the adhesion with the copper foil not subjected to the black treatment. Came to complete.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a multilayer printed wiring in which a circuit-processed single-sided or double-sided copper-clad laminate is laminated with a prepreg obtained by impregnating a base material with a thermosetting resin and drying the laminate. In the method for producing a plate, (1) a terminal bifunctional linear polymer epoxy resin having an average epoxy equivalent of 450 or more and 6000 or less, and (2) a curing agent on the circuit surface of the circuit-processed copper-clad laminate. A multilayer printed wiring board in which an undercoat agent containing an aromatic polyamine having an ether bond or an ether bond and a sulphone bond as an essential component is applied as a base material, and then epoxy resin is impregnated into a base material and dried prepregs are laminated and laminated. And a manufacturing method thereof.

Hereinafter, the present invention will be described in detail. An object of the present invention is, as described in the section of the problem to be solved by the invention, to manufacture a multilayer printed wiring board which does not require black treatment of the inner copper foil surface. As a result of earnest studies on the composition of the undercoat agent, the present inventor has found that a certain equivalent amount of a terminal bifunctional linear polymer epoxy resin is used not only when black treatment is performed but also when black treatment is not performed. It was found that the combination of and a specific aromatic polyamine can secure sufficient adhesion and heat resistance to the inner layer copper foil.

As the epoxy resin, a terminal 2 having an average epoxy equivalent of 450 or more and 6000 or less obtained by reacting a bifunctional phenol with epihalohydrin in a strong alkali is used.
Functional linear polymer epoxy resin and terminal 2 having an average epoxy equivalent of 450 or more and 6000 or less obtained by alternate copolymerization reaction of bifunctional epoxy resin and bifunctional phenol
Any of the terminal bifunctional linear polymer epoxy resins having an average epoxy equivalent of 450 or more and 6000 or less, such as a functional linear polymer epoxy resin, can be used, or a combination of several types can be used. It is possible. . For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, tetrabromobisphenol A type epoxy resin, propylene oxide bisphenol A type epoxy resin, bisphenol S type epoxy resin, biphenyl type epoxy resin, 2,6 naphthol type diglycidyl ether polymerization. Products, bisphenol A type epoxy resin and tetrabromobisphenol A copolymer, bisphenol F type epoxy resin and tetrabromobisphenol A
Examples thereof include copolymers, bisphenol S type epoxy resins and tetrabromobisphenol A copolymers.

Regarding the aromatic polyamine, when considering the adhesion to the copper foil not subjected to the black treatment, when an aromatic polyamine having an ether bond or an ether bond and a sulfone bond is used as a curing agent, other than that, As compared with the case of the aromatic polyamine, the adhesion is improved by about 10 to 20%. It is considered that this is because any of the bonds does not directly make a chemical bond with the copper element having the oxidation number of 0, but has high chemical affinity. 4,4′-diaminodiphenyl ether, bis [4- (4-aminophenoxy) phenyl] ether as the aromatic polyamine,
4,4'-bis (4-aminophenoxy) biphenyl,
Examples thereof include 1,4-bis (4-aminophenoxy) benzene and bis [4- (4-aminophenoxy) phenyl)] sulfone. The amount of the aromatic amine to be blended can be used in the range of 0.1 to 2.0 in terms of an equivalent ratio to the epoxy resin, but both heat resistance (particularly solder heat resistance after moisture absorption) and interlayer adhesion are compatible. Therefore, 0.5 to 1.5 is a preferable range. Usually, the equivalent ratio of the aromatic amine to the epoxy resin is approximately 1, but in the present invention, larger or smaller values can be used. If the equivalent ratio is larger or smaller than the above range, the heat resistance and the adhesiveness tend to decrease.

The molecular weight of the epoxy resin will be mentioned.
When considering the adhesion to copper that has not been black-treated, it has been found that the larger the molecular weight, the higher the adhesion tends to be, but the solder heat resistance after moisture absorption is likely to deteriorate.
Although there are some differences in absolute value depending on the base skeleton of the epoxy resin and the base skeleton of the aromatic polyamine, this tendency hardly changes. The inner layer peel strength practically required for epoxy-based multilayer printed wiring boards (FR-4 etc.) is generally said to be 0.6 kN / m, and it is an epoxy resin having an average epoxy equivalent of 450, and the inner layer peel strength ( 0.7 kN / m (without black treatment)
It is a practical level and the average epoxy equivalent is 600.
When it exceeds 0, the peel strength of the inner layer (no black treatment)
Is 1.1 kN / m, which is a sufficient level, the epoxy groups that are the cross-linking sites are too far apart from each other, and the required heat resistance is difficult to develop.

In order to improve the curability of the undercoat agent, it is preferable to use a curing accelerator together. Such a curing accelerator is not particularly limited, but examples of the imidazole curing accelerator include 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenyl-4-methylimidazole, 2, 4'-diamino-
6- [2'-ethyl-4'-methylimidazolyl-
(1 ′)] Ethyl-s-triazine, 2-methylimidazole-isocyanuric acid adduct, 2-methylimidazole-trimellitic acid adduct, and the like, and as the phosphine-based curing accelerator, triphenylphosphine, triphenyl There are phosphine phenol salts and the like, and more preferably 2-undecylimidazole, 1-cyanoethyl-
2-undecylimidazole or 2,4-diamino-6
-{2'-Undecylimidazolyl- (1 ')} ethyl-s-triazine can be used alone or in combination. The amount of the curing accelerator based on 100 parts by weight of the epoxy resin is preferably 0.2 to 0.9 parts by weight. If the addition amount exceeds 0.9 parts by weight, the curing speed is too fast to deteriorate the moldability, and the solder heat resistance and the interlayer adhesion after moisture absorption are not compatible, or both properties are deteriorated. On the other hand, if the addition amount is less than 0.2 parts by weight, the heat resistance becomes insufficient due to insufficient curing, and the adhesiveness also decreases.

When the above-mentioned composition is applied to the inner layer circuit board, the viscosity can be adjusted with a solvent. As the solvent,
Acetone, methyl ethyl ketin, toluene, xylene,
Examples thereof include ethylene glycol monoethyl ether and its acetate compound, propylene glycol monoethyl ether and its acetate, dimethylformamide, methanol and ethanol.

Further, depending on the coating method, it is possible to mix an inorganic filler for imparting thixotropy. For example, aluminum oxide, hydrated silica, alumina,
Antimony oxide, barium titanate, colloidal silica, calcium carbonate, calcium sulfate, mica, silica, silicon carbide, talc, titanium oxide, quartz,
Examples thereof include zirconium oxide, zirconium silicate, boron nitride, carbon and graphite.

Further, in order to improve the adhesion with copper or the adhesion with the inorganic filler, it is possible to add a coupling agent. As the coupling agent, a silane coupling agent, a titanate coupling agent, an aluminum chelate coupling agent or the like can be used, and examples thereof include chloropropyltrimethoxysilane, vinyltrichlorosilane, and γ.
-Glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, isopropyltriisostearoyl titanate, isopropyltrimethacrytitanate , Isopropyl tri (dioctyl phyllophosphate) titanate, isopropyl isostearoyl di-4-aminobenzoyl titanate and the like.

Further, for defoaming or defoaming, it is possible to add a silicone defoaming agent, an acrylic defoaming agent, a fluorine-containing surfactant and the like. Further, it is generally known that imparting toughness is very effective for improving the peel strength of the copper foil. For example, carboxy-terminated butadiene acrylonitrile rubber (Ube Industries Co., Ltd. C
TBN), epoxy-modified polybutadiene rubber, etc. can be added.

The undercoating agent can be applied by a roll coater, a curtain coater, a casting method,
There are methods such as spinner coater and screen printing,
Coating is possible by either method. Further, the method is not limited to the above-described coating method as long as the method can apply the inner circuit surface without leakage. In either method, since the undercoating agent has the optimum viscosity required, it is necessary to adjust the reactive diluent, the type of solvent, the type of inorganic filler, the particle size, and the blending amount depending on the coating method. .

The cured state of the undercoat agent will be mentioned. Generally, the cured state can be divided into an A stage state which is a completely uncured state, a B stage state which is a semi-cured state, a gel state in which further curing is promoted, and a C stage state which is a completely cured state. it can. Any state may be used for this purpose.

In the present invention, by using the undercoating agent having the above-mentioned specific formulation, the black treatment which has been conventionally required for the multilayer printed wiring board is completely unnecessary. Therefore, it is expected that the number of man-hours spent for quality control in the black processing step and the production cost will be reduced. Furthermore, since the undercoat layer is formed on the upper surface of the patterned double-sided copper-clad laminate, the pattern gap can be filled with resin in advance, so even if prepregs are stacked and laminated, air bubbles remain. It can be molded without causing it. Therefore, according to the copper foil residual rate of the conventional inner layer circuit,
Although the resin amount of the prepreg and the fluidity at the time of heating were changed, the necessity was completely eliminated. That is, since the plate thickness accuracy does not depend on the copper foil residual rate of the inner layer circuit, it becomes possible to cope with a few kinds of prepregs,
Therefore, it is possible to manufacture a large amount of small quantities of prepreg. Furthermore, since the time required to fill the inner layer copper foil etched portion of the prepreg is completely eliminated, the processing time required for the press, which conventionally took 140 minutes or more for one press, can be shortened to about 60 minutes at most. This will significantly reduce the manufacturing cost, and the man-hours spent for quality control and inventory control.

[0018]

EXAMPLES The present invention will now be described in detail based on examples.

(Example 1) 100 parts by weight of diglycidyl ether bisphenol A (average epoxy molecular weight 450) was dissolved in 120 parts by weight of butyl cellosolve acetate. There, 4,4'-diaminodiphenyl ether 9.
When 0 part by weight was added and stirred, it was easily dissolved. Furthermore, 0.5 parts by weight of 2-ethyl-4-methylimidazole,
After adding 80 parts by weight of calcium carbonate having an average particle diameter of 1 to 2 μm, 20 parts by weight of fine silica R-972 (manufactured by Nippon Aerosil Co., Ltd.), and 1 part by weight of γ-glycidoxypropyltrimethoxysilane, a triple roll. Kneaded by. Defoaming was performed with a vacuum defoamer at a degree of vacuum of 3 mmHg for 5 minutes to obtain an undercoat agent. Next, the glass epoxy double-sided copper clad laminate having a substrate thickness of 0.1 mm and a copper foil thickness of 35 μm was surface-polished, soft-etched to remove rust-preventive treatment, and then processed into a circuit by etching. Normally, black processing is performed after circuit processing, but black processing is not performed at all, the undercoat agent is screen-printed on one side of the inner layer circuit board, and then heated at 130 ° C for 20 minutes in a dryer to be tack-free. Then, the undercoat agent was applied to the back surface in the same manner and dried.

Further, FR-4 prepreg 100 μm thick (EI-6765 manufactured by Sumitomo Bakelite Co., Ltd.), which was obtained by impregnating a base material with an epoxy resin and drying it, was applied to both sides of the above-mentioned dried thermosetting resin undercoat agent. The copper foil with a thickness of 18 μm is overlaid on top of each other one by one, and the maximum temperature of the material is 170 ° C in a vacuum press, and the material is heated and cured for 60 minutes including heating and cooling, and a multilayer printed wiring board Was produced. The properties of the laminate are shown in Table 1.

(Examples 2 to 5 and Comparative Examples 1 to 3) A multilayer printed wiring board was prepared and evaluated in the same manner as in Example 1 except that the resin composition of the undercoat agent was changed. The resin composition and the evaluation results are shown in Table 1.

(Comparative Example 4) Base material thickness 0.1 mm, copper foil thickness 3
A 5 μm glass-epoxy double-sided copper clad laminate was surface-polished, soft-etched to remove the rust-preventive treatment, and then etched to form a circuit. As in the first embodiment, without performing the black processing,
FR-4 prepreg 100 μm thick (Sumitomo Bakelite Co., Ltd. EI-
6765) is laminated on both sides one by one, and one copper foil with a thickness of 18 μm is laminated on the upper surface, and the maximum temperature reached by the vacuum press is 170 ° C.
It was heat-cured for 40 minutes to prepare a multilayer printed wiring board. The properties of the laminate are shown in Table 1.

Comparative Example 5 A multilayer printed wiring board was prepared and evaluated in the same manner as in Comparative Example except that the double-sided copper clad laminate used for the inner layer was subjected to ordinary black treatment.
Table 1 shows the evaluation results.

[0024]

[Table 1]

(Evaluation Conditions) Inner Layer Copper Foil Peel Strength After the multilayer printed wiring board was prepared, the copper foil of the inner layer circuit board and the prepreg were mechanically peeled off, and the exposed inner layer copper foil was pulled with an undercoating agent. The peel strength with the inner layer copper foil was measured. Moisture absorption soldering heat resistance Multilayer prepreg wiring board is PCT condition (125 ℃, 2.3
Moisture absorption treatment was performed at atmospheric pressure) for 3 hours, and then floated in a solder bath at 260 ° C. for 2 minutes, and the presence or absence of blistering was monitored. Halo property A multi-layer prepreg wiring board is drilled with 100 holes using a small diameter drill with a diameter of 0.4 mm, electroless plating is performed, and then the inner layer copper foil and the undercoat agent are mechanically peeled off, causing a halo phenomenon. Observing the situation with an optical microscope,
It was measured.

[0026]

In the present invention, by using the above-mentioned specific undercoating agent, the black treatment which has been conventionally required for the multilayer printed wiring board is completely unnecessary. Therefore, it is expected that the number of man-hours spent for quality control in the black processing step and the production cost will be reduced. Furthermore, in order to fill the step of the inner layer circuit by applying the undercoat agent in advance,
Bubbles existing in the gaps between the circuits are eliminated, and voids are not generated and good moldability can be obtained without applying pressure for a long time as in the conventional vacuum press. At the same time, it is not necessary to change the type of prepreg according to the residual copper foil ratio of the inner circuit, so that the manufacturing time of the multilayer printed wiring board can be significantly reduced. In addition, it is expected that a huge number of man-hours will be spent and a road for automating the manual prepreg set will be opened.

Claims (2)

[Claims] 1. A method for producing a multilayer printed wiring board, comprising laminating and molding a circuit-processed single-sided or double-sided copper-clad laminate with a base material impregnated with a thermosetting resin and dried to form a laminate. On the circuit surface of the processed copper-clad laminate, (1) a terminal bifunctional linear polymer epoxy resin having an average epoxy equivalent of 450 or more and 6000 or less, and (2) an ether bond or an ether bond and a sulfone as a curing agent. A method for producing a multilayer printed wiring board, comprising applying an undercoating agent containing an aromatic polyamine having a bond as an essential component, then impregnating an epoxy resin into a base material, and laminating and molding a prepreg that has been subjected to a drying treatment. 2. The method for manufacturing a multilayer printed wiring board according to claim 1, wherein the circuit-processed double-sided copper-clad laminate is not subjected to an oxidation treatment.