JPH0423654B2 - - Google Patents

Description

[Detailed description of the invention]

a Field of Industrial Application The present invention relates to a method for manufacturing an epoxy resin printed circuit board that has a good balance between heat resistance, dimensional stability, and workability that are superior to conventional ones. This is a manufacturing method that attempts to achieve the above object by using a compound composition. b. Prior Art As the density of large-scale integrated circuits increases and electronic components become smaller, the printed wiring boards that receive them are also becoming more dense and multilayered. By the way, epoxy resin is generally used as a matrix resin for manufacturing printed circuit boards. That is, epoxy resins generally have excellent electrical properties, excellent adhesion to glass fibers and copper plates, excellent curing workability, etc., and have come to be widely used for printed circuit boards.
As the epoxy resin for such printed circuit boards, a combination of a bisphenol A-glycidyl ether type epoxy compound and an amine curing agent including dicyandiamide is generally used. However, as higher density and multilayer technology progresses, it has become clear that the above-mentioned general epoxy resins lack performance in terms of heat resistance, dimensional stability, etc., and improvements in these are strongly desired. It has reached the point where For this reason, for example, polyimide resins, which have better heat resistance than epoxy resins, are beginning to be used for this purpose, but they are inevitably inferior to epoxy resins in terms of workability and adhesion. c Problems to be Solved by the Invention Therefore, the present invention solves the above-mentioned drawbacks of conventional printed circuit boards, and develops an epoxy resin-based material that has a good balance between heat resistance, dimensional stability, and workability. The present invention seeks to provide a method for manufacturing a substrate. d. Means for Solving the Problems As a result of extensive research into heat-resistant epoxy resins that can be used for such purposes, the inventors focused on α-naphthol novolak glycidyl ether type epoxy compounds. In such compounds, by replacing phenol with naphthol having a larger aromatic ring, an epoxy resin can be obtained which has heat resistance and low moisture absorption that are numerically superior to epoxy resins derived from the corresponding phenol novolak glycidyl ether compounds. It will be done. However, if such an epoxy compound is used alone, the epoxy resin after curing becomes too hard, causing problems in terms of flexibility, adhesiveness, and workability when used as a printed circuit board. However, not only when a specific bisphenol A-diglycidyl ether type epoxy compound is used alone, but also when a phenol novolac glycidyl ether type epoxy compound is used in addition to it to improve its heat resistance. do,
The present invention was achieved by discovering that better heat resistance can be exhibited. That is, the present invention provides a method for manufacturing a printed circuit board, which includes a step of impregnating and laminating a fibrous base material with an epoxy resin composition and a step of combining a conductive object therewith, as the epoxy resin composition:
Bisphenol A- with an epoxy equivalent of 170 to 3500
A printed circuit board characterized in that an epoxy mixture consisting of 5 to 90 parts by weight of a glycidyl ether type epoxy compound and 95 to 10 parts by weight of α-naphthol novolak glycidyl ether having an epoxy equivalent of 210 to 400 is used as a main component. This is the manufacturing method. The α-naphthol novolac glycidyl ether type epoxy compound used in the method of the present invention is
α-Naphthol novolak is obtained by reacting formaldehyde in the presence of an acidic catalyst under the same conditions as when α-naphthol is used instead of phenol to obtain phenol novolak, which is also commonly used. According to the method for producing aryl glycidyl ether, in the presence of an acid acceptor,
Obtained by epichlorohydrin reaction. As the acidic catalyst, citric acid, phosphoric acid, hydrochloric acid, etc. are preferably used, and as the formaldehyde, formalin is preferably used. The degree of condensation of α-naphthol novolak can be adjusted by adjusting the molar ratio of α-naphthol and formaldehyde used and the reaction conditions. It is also possible to use a part of α-naphthol by replacing it with phenol, cresol, hydroxybenzaldehyde, etc. In general, novolaks containing on average 2 to 12, more preferably 3 to 10 α-naphthol nuclei in one molecule are preferably used. In the reaction between α-naphthol novolac and epichlorohydrin, caustic soda or the like is preferably used as a receptor for hydrogen chloride produced as a by-product. Thus, the obtained α-naphthol novolak glycidyl ether compound has an epoxy equivalent of
210 to 400 g/eq. is used. Particularly preferred are those having an epoxy equivalent of 210 to 300 g/eq. The bisphenol A-glycidyl ether epoxy compound, which is one of the essential components, can be obtained by the reaction of bisphenol A and epichlorohydrin in the presence of an acid acceptor. It can be obtained at In the present invention, the epoxy equivalent is 170 to 3500.
g/eq. is used, especially 200 to 1000
g/eq. is preferred. A predetermined proportion of such epoxy compound and epoxy curing agent are dissolved in a suitable common solvent to prepare a varnish, which is impregnated into a fibrous base material such as a reinforcing fiber cloth, dried and heat treated to form an epoxy resin in a B-stage state. As a result, so-called prepreg is created.
As an epoxy curing agent, dicyandiamide,
4,4′-diaminodiphenylsulfone (DDS),
Aromatic amine curing agents such as 4,4'-diaminodiphenylmethane and m-phenylenediamine are particularly preferably used. Among these, DDS and dicyandiamide are preferred from the viewpoint of the pot life of the B-stage prepreg and the Tg of the cured product. In addition to the curing agent that chemically reacts with the epoxy resin, a curing accelerator that adjusts the curing speed can also be appropriately selected and used. Cationic and anionic accelerators are known, but acid fluoride boron monoethylamine complex salts and the like can also be suitably used. The ratio of epoxy compound and curing agent used is
Generally, a ratio near the chemical reaction equivalent of both is used. Solvents used to create a varnish containing such an epoxy compound and a hardening agent include ether solvents such as tetrahydrofuran and dioxane, ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, and ester solvents such as ethyl acetate and butyl acetate. A polar solvent such as an amide solvent such as dimethylformamide or dimethylacetonamide is used as the main solvent. The selection of the solvent and the concentration may be appropriately selected in consideration of the viscosity of the varnish during impregnation and the evaporation rate of the solvent. Glass fiber woven cloth treated with a so-called silane coupler such as epoxy silane is generally used as the reinforcing fiber cloth serving as the fibrous base material, but glass fiber matte can also be used alone or in combination with glass fiber woven cloth. I can do it. Other fibers such as aramid fiber mat and/or nonwoven fabric can also be used by taking advantage of the fact that the fibers have an extremely small coefficient of thermal expansion in the fiber axis direction. Fibrids obtained from these aramids and/or paper in which these aramid fibers are inserted can also be used. Ordinary cellulose paper can also be used. Impregnation of the varnish into the fiber cloth, drying, and heat treatment for B-staging can be carried out by various well-known methods. That is, any method can be used, such as a method in which a long fiber cloth is used and the treatment is applied continuously, or a method in which fibers of a certain size are sequentially treated in a batch manner. Regarding the processing conditions for drying and B-staging,
The reaction conditions vary depending on the type of solvent and curing agent used, but they can be determined by simple experiments. Depending on the thickness of the laminate to be manufactured from the thus obtained prepreg, an appropriate number of sheets are stacked,
When trying to obtain a copper-clad laminate for use in the so-called substructive method, a laminate can be obtained by overlapping copper foil on both sides or one side and hot pressing. The copper foil used in such a copper-clad laminate is a rolled copper foil or an electrolytic copper foil, and the surface to be bonded to the prepreg is rough and has been subjected to an adhesion enhancement treatment. When obtaining a multilayer board, after the copper-clad laminate is processed for wiring, it is further integrated with prepreg, so both sides of the copper foil are used for adhesion to the resin. In addition to the form of copper-clad laminates for the substructive method, laminates were created only by laminating prepregs, a nucleating agent for electroless plating was attached to the surface or within the resin, and adhesion promotion treatment was applied. Thereafter, a circuit pattern is created using a resist, and a circuit made of copper or the like is created in the areas where the resist is not adhered by electroless plating processing, so that it can be used as a substrate using the so-called additive method. Furthermore, a method may be employed in which a circuit is formed on the laminate by screen printing or the like using a so-called conductive paint containing a large amount of silver or copper powder. e Effects of the Invention Regardless of the conductor circuit manufacturing method, the circuit board obtained using the epoxy compound mixture according to the present invention is superior to that of conventional epoxy resin due to its excellent heat resistance, dimensional stability, and low moisture resistance. It exhibits excellent practical performance that exceeds that of laminated plates, and is excellent for high-density multilayer plates. f Examples The present invention will be described in detail below with reference to Examples and Comparative Examples. The examples are illustrative and not limiting. Examples 1 and 2 and Comparative Examples 1 and 2 (1) Materials used (a) For the α-naphthol novolac glycidyl ether type epoxy compound, the epoxy equivalent prepared by the manufacturing method as explained in this article
250g/eq. Use a compound with a melting point of 65 to 93℃ (b) Use a commercially available bisphenol A-glycidyl ether type epoxy compound as Epicote 1001 (epoxy equivalent 450 to 500g/
eq.) (c) As a phenol novolac glycidyl ether type epoxy compound for comparison, a commercially available one as Epicoat 154 (epoxy equivalent: 176-181) was used. (d) As a glass cloth, Nittobo's
Use WE18K105BZ-2 (basis weight 205g/ ^m2 ) (e) Use 3μm copper foil made by Nikko grade electrolytic copper foil (f) Use diaminophenyl sulfone (DDS), boron trifluoride monoethylamine complex salt, methyl ethyl ketone, etc. Commercially available products were used (2) Conditions for trial production of copper-clad laminates A trial production of copper-clad laminates was carried out under the conditions shown in Table 1. (3) Performance measurement of the obtained copper-clad laminate The results are summarized in Table 2.

【table】

[Table] As can be seen from the above results, Examples 1 and 2 maintain workability comparable to Comparative Example 1, which is a conventional heat-resistant epoxy composition, and α-naphthol novolac glycidyl ether type epoxy alone It can be seen that this is much improved compared to Comparative Example 2. The heat resistance of the obtained laminate is close to Comparative Example 2, and is greatly improved compared to Comparative Example 1, and measurement items related to the flexibility of the laminate, such as peel strength and soldering heat resistance, are similar to Comparative Example 2. It can be seen that it is close to Comparative Example 1, and is significantly improved over Comparative Example 2.

Claims (1)

[Claims] 1. In a method for manufacturing a printed circuit board, which includes a step of impregnating and laminating a fibrous base material with an epoxy resin composition and a step of combining a conductive object therewith, the epoxy resin composition has an epoxy equivalent of 170 to 3,500. A print characterized in that an epoxy mixture consisting of 5 to 90 parts by weight of a bisphenol A-glycidyl ether epoxy compound and 95 to 10 parts by weight of α-naphthol novolak glycidyl ether having an epoxy equivalent of 210 to 400 is used as a main component. A method for manufacturing circuit boards.