JPS62169828A - Production of substrate for printed circuit - Google Patents

Abstract

PURPOSE:To obtain the titled substrate excellent in heat resistance, dimensional stability, low hygroscopicity and workability, by combining a laminate of fibrous bases impregnated with a specified resin composition with an electrconductive object. CONSTITUTION:An epoxy resin composition is obtained by mixing 5-90pts.wt. bisphenol A-glycidyl ether epoxy compound of an epoxy equivalent of 170-3,500g/eg with 95-10pts.wt. alpha-naphthol novolak glycidyl ether epoxy compound of an epoxy equivalent of 210-400g/eq. Fibrous bases, such as glass fiber cloth, treated with, e.g., a silane coupler such as an epoxysilane are impregnated with a varnish obtained by dissolving the above resin composition, a curing agent such as dicyandiamide and a cure accelerator such as a boron trifluoride/monoethylamine complex in a polar solvent such as methyl ethyl ketone, laminated, dried and heat-treated. An electroconductive object such as a rolled copper foil or an electrolytic copper foil is laid upon the laminate and heat-pressed to obtain the titled substrate.

Description

[Detailed Description of the Invention] a. Industrial Application Field The present invention relates to a 133 method for producing an epoxy resin-based printed circuit board that has a good balance between heat resistance, dimensional stability, and workability that are superior to conventional methods. More specifically, the above objective can be achieved by using a specific epoxy compound composition.
This is a manufacturing method that makes υ.

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. In other words, epoxy resins generally have excellent electrical properties,
It also has excellent adhesion and curing workability to glass fibers and copper plates, and has come to be widely used for printed circuit boards.

As the epoxy resin for such printed circuit boards, a combination of a bisphenol A diglycidyl 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 general epoxy resins described above lack performance in terms of heat resistance, dimensional stability, etc., and improvements in these are strongly desired. It has arrived. For this reason, 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.

Therefore, if an epoxy resin can be obtained that can exhibit heat resistance close to that of polyimide while retaining the workability and adhesive properties that are characteristic of epoxy resins, it would be extremely advantageous to use it for this purpose.

As a result of intensive studies on heat-resistant epoxy resins that can be used for such purposes, the inventors of the present invention focused on α-naphthol novolak glycidyl ether type epoxy compounds.

By replacing phenol with naphthol, which has a larger aromatic ring, such a compound can provide an epoxy resin that has heat resistance and low moisture absorption that are numerically superior to epoxy resins derived from the corresponding phenol novolac glycidyl ether compounds. . 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, when a specific bisphenol A-diglycidyl ether type epoxy compound is used alone, for example, a phenol novolak glycidyl ether type epoxy compound is used in addition to it to improve its heat resistance. 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 the epoxy resin composition with a conductive object, in which the epoxy resin composition has an epoxy equivalent of 170-35
5 to 90 parts by weight of a bisphenol A-glycidyl ether type epoxy compound of No. 00 and an epoxy equivalent of 210 to 4.
00 α-naphthol novolak glycidyl ether 9
This method of manufacturing a printed circuit board is characterized in that an epoxy mixture consisting of 5 to 10 parts by weight is used as a main component.

The α-naphthol novolak/glycidyl ether epoxy compound used in the method of the present invention can be reacted in the presence of formaldehyde and an acidic catalyst under the same conditions as those used to obtain phenol novolac using α-naphthol instead of phenol. The α-naphthol novolak obtained by the above method is reacted with epichlorohydrin in the presence of an acid acceptor, also according to the general method for producing aryl glycidyl ether.

As the acidic catalyst, oxalic 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 reaction conditions. It is also possible to replace a part of α-naphthol with phenol, cresol, human O-oxybenzaldehyde, etc. Generally, there are on average 2 to 12 α-naphthol nuclei in one molecule, more preferably 3 to 1
A novolak containing 0 is preferably used. This α−
In the reaction of naphthol novolak and epichlorohydrin, caustic soda or the like is preferably used as a receptor for hydrogen chloride produced as a by-product.

The α-naphthol novolak glycidyl ether compound thus obtained has an epoxy equivalent of 210 to 4009.
/eQ is used. Especially when the epoxy equivalent is 21
0 to 300 g/eq, preferably later.

The bisphenol A-glycidyl ether epoxy compound, which is one of the essential components, is obtained by the reaction of bisphenol A-glycidyl ether with epichlorohydrin in the presence of an acid acceptor, and various epoxy equivalents are commercially available and easily available.

In the present invention, the epoxy equivalent is 170 to 3500f.
f/(!Q, later used, but especially 200 to 10
00ri/eQ is preferable.

Dissolve a predetermined proportion of the epoxy compound and epoxy curing agent in a suitable common solvent, create a varnish, and use it! I Impregnate a cloth base material such as reinforcing fiber cloth, dry it, and heat-treat it.
- Creating a so-called prepreg as an epoxy resin in a stage state. Examples of the epoxy curing agent include dicyandiamide and 4,4'-diaminodiphenylsulfone<D
DS).

Aromatic amine curing agents such as 4.4'-diaminodiphenylmethane and m-phenylenediamine are particularly preferably used. Among them, DDS and dicyandiamide are B
- Pot life of stage prepreg and Tg of cured product
It is suitable from the viewpoint of

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. Although cationic and anionic accelerators are known, acid boron fluoride monoethylamine complex salts and the like can also be suitably used. The ratio of the epoxy compound and the curing agent to be used is generally the same as the chemical reaction between the two.

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 didymelbormamide or dimethylaledamide 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.

As the reinforcing fiber cloth, a glass fiber woven cloth treated with a so-called silane coupler such as epoxy silane is generally used, but glass fiber pine 1 to 1 can also be used alone or in combination with a glass fiber woven cloth. Other fibers such as aramid fiber mats and/or nonwoven fabrics can also be used by taking advantage of the fact that these 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 sequentially treated, or a method in which m-threads 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 the conditions 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 prepregs may be stacked together to obtain a copper-clad laminate for use in the so-called substrative method. They can be stacked together to form a laminate by 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 are created only by laminating prepregs, a nucleating agent for electroless plating is attached to the surface or in the resin, and after adhesion promotion treatment, resist is applied. Create a circuit pattern by
It can be used as a substrate using the so-called additive method, in which a circuit is formed using copper or the like in areas where resist is not attached by electroless plating. Furthermore, a method may be used 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.

Regardless of the conductor circuit preparation method, the circuit board obtained using the epoxy compound mixture according to the present invention has excellent heat resistance, one-dimensional stability, and low moisture absorption, which surpasses conventional epoxy resin laminates. It exhibits practical performance and is excellent for high-density multilayer boards.

The present invention will be described in detail below with reference to Examples and Comparative Examples. The examples are illustrative and not limiting.

(1) Materials used (a) For the α-naphthol novolac glycidyl ether type epoxy compound, use one prepared by the manufacturing method as explained in the text, with an epoxy equivalent weight of 250 g/eQ, and a melting point of 65 to 93°C.
- Glycidyl ether type epoxy compound is Epicote 1
Use commercially available Chino as 001 (epoxy equivalent: 450~
500g/(!Q, ) (Tsukasa) As a phenol novolak glycidyl ether type epoxy compound for comparison, Ebicoat 154
(Epoxy equivalent: 176-181) Use a commercially available glass cloth (D) As the glass cloth, use Nittobo WE18 105BZ-2 (eye position 205!?/G) (E)
Diaminodiphenyl sulfone (DDS) is used.

Commercially available boron trifluoride monoethylamine complex salts, methyl ethyl ketone, etc. 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.

(Leaving space below) Table 2 Performance of prototype copper-clad laminate (Measurement method - Based on JIS C6481 tI!) As can be seen from the above results, Examples 1 and 2 are conventional heat-resistant epoxy compositions. It can be seen that the workability is maintained at the same level as Comparative Example 1, and it is much improved compared to Comparative Example 2 in which α-naph 1-lunovolak glycidyl ether type epoxy is used alone.

1 The heat resistance of the smoothed laminate is close to that of Comparative Example 2.
The measurement items related to the flexibility of the laminate, such as peel strength and soldering heat resistance, are close to Comparative Example 1, and are significantly improved compared to Comparative Example 2. I can see that it is.

Claims (1)

[Claims] In a method for producing 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 includes bisphenol having an epoxy equivalent of 170 to 3,500. A-Glycidyl ether epoxy compound 5~
90 parts by weight and 95 to 10 parts by weight of α-naphthol novolak glycidyl ether having an epoxy equivalent of 210 to 400.