JP2002217549A - Printer composition for multilayer printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a primer composition for a multilayer printed wiring board, which is applied for raisin adhesion between a copper circuit 2 and an insulation film or a prepreg 4, when the printed wiring board where the copper circuit 2 is formed in a surface is laminated via an insulation film or the prepreg 4, and can enhance adhesion between the copper circuit 2 and the insulation film or the prepreg 4 without performing blackening treatment or wet-etching roughening treatment of copper, etc., for a surface of the copper circuit 2. SOLUTION: Olefinic copolymer resin, having carboxylic group in a side-chain such as ethylene acrylic acid copolymer, is incorporated in primer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer printed wiring board in which a printed circuit board having a copper circuit formed on the surface thereof is laminated via an insulating film or a prepreg. The present invention relates to a primer composition used for enhancing the property.

[0002]

2. Description of the Related Art Conventionally, most conductors of a multilayer printed wiring board are made of copper. In order to improve the adhesion between the copper conductor on the inner layer board of the multilayer printed wiring board and the insulating film or prepreg, a wet etching (chemical polishing) process is performed. For example, after etching (chemical polishing) the copper foil surface of the inner layer plate with a cupric chloride solution, a ferric chloride solution, a sulfuric acid hydrogen peroxide solution, etc., the surface is oxidized to form copper oxide fine protrusions, A blackening treatment for allowing the resin laminated on the copper foil surface to be firmly fixed to the copper foil surface by the anchoring action of the fine projections, and sulfuric acid and hydrogen peroxide disclosed in JP-A-06-112646. Examples include wet processing in which only copper is etched using water without forming a copper oxide.

[0003]

However, since the above-described blackening and etching processes are wet processes, there is a problem that the steps are complicated. Also,
Since it is a wet treatment, there is a problem that waste liquid is generated, which is not preferable in terms of environmental hygiene.

[0004] Further, as electronic devices have become lighter, thinner, smaller and have higher performance, printed wiring boards have also become multilayered, thinner, and denser. Accordingly, the thickness of the copper layer has been reduced from 36 μm to 9 μm. When this surface is etched by 1 μm to 3 μm, the influence increases as the copper becomes thinner. Since the blackening process and the wet etching process in general involve copper roughening, it is considered to be a process that goes against the copper thinning process.

SUMMARY OF THE INVENTION An object of the present invention is to provide a multilayer printed wiring which can improve the adhesion between a copper circuit shiny surface and an insulating film or prepreg without performing a copper circuit surface blackening treatment or a copper etching roughening treatment. An object of the present invention is to provide a primer composition for a board.

[0006]

SUMMARY OF THE INVENTION According to the present invention, when a printed wiring board having a copper circuit formed on its surface is laminated via an insulating film or prepreg, the adhesion between the copper circuit and the insulating film or prepreg is improved. It is a primer resin composition to be applied to enhance the performance, and is characterized by containing an olefin copolymer resin having a carboxyl group in a side chain.

The olefin copolymer resin having a carboxyl group in the side chain used in the present invention includes olefins such as ethylene and propylene and α, β-olefins having a carboxyl group such as maleic acid, acrylic acid and methacrylic acid.
Resins obtained by copolymerizing with an ethylenically unsaturated carboxylic acid are exemplified. Among these, an ethylene acrylic acid copolymer resin is particularly preferably used. The acrylic acid content of the ethylene acrylic acid copolymer resin is, for example, 2 to 50
% By weight. If the acrylic acid content is low, the solubility in solvents, water, etc., and the adhesion between the copper circuit and the insulating film or prepreg are reduced, and if the acrylic acid content is too high, the primer has water resistance and chemical resistance. May decrease.

In the olefin copolymer resin used in the present invention, other polymerizable monomers may be copolymerized in addition to the olefin and the α, β-ethylenically unsaturated carboxylic acid. For example, acrylic ester, methacrylic ester, styrene, vinyl chloride, vinyl acetate, acrylonitrile, methacrylonitrile, and the like may be copolymerized.

The weight average molecular weight of the olefin copolymer resin used in the present invention is 3,000 to 100,000.
It is preferred that it is about. The olefin copolymer resin used in the present invention may have its carboxyl group neutralized with a base such as ammonia, alkali, or amine. By neutralizing with a base, an aqueous dispersion can be obtained. Generally, the greater the content of carboxyl groups, the easier it is to disperse in water. When the olefin copolymer resin is neutralized with a base, the neutralization ratio is preferably about 20 to 100%, and more preferably about 30 to 80%.

The primer composition of the present invention may contain other additives in addition to the olefin copolymer resin. For example, a component that increases the affinity with the surface of the copper circuit, a component that increases the affinity with the resin of the insulating film, or the like may be contained. The olefin copolymer resin is preferably contained in an amount of 10% by weight or more in the solid content of the primer composition of the present invention.

The multilayer printed wiring board using the primer composition of the present invention is not particularly limited as long as the printed wiring board having a copper circuit formed on its surface is laminated via an insulating film or prepreg. Absent. As the printed wiring board to be laminated, for example, a printed circuit board formed by etching a double-sided copper-clad laminate or a single-sided copper-clad laminate by a conventionally known photolithography method or a subtractive etching method is used. As the insulating film, for example, phenol resin, epoxy resin is an amine,
A thermoplastic or thermosetting type such as an ink cured with a curing agent such as imidazole, phenol, or acid anhydride, or a laminate film of polyphenylene ether or polyimide or a modified product thereof is used.
As the prepreg, a glass fiber impregnated with a resin such as a phenol resin or an epoxy resin is used.

FIG. 1 is a cross-sectional view for explaining a state in which printed wiring boards are laminated using the primer composition of the present invention. Copper circuit 2 is formed on the surface of printed wiring board 1. The copper circuit 2 is formed by etching a copper foil provided on the printed wiring board 1 into a predetermined pattern. The primer 3 of the present invention is applied on the surface of the printed wiring board 1 on which the copper circuit 2 is formed. The coating method is not particularly limited, and is appropriately selected depending on the solution state, viscosity, and the like of the primer 3 to be used. After the primer 3 is applied, a prepreg or an insulating film 4 is disposed thereon, and a printed wiring board (not shown) is placed thereon, heated and pressed. When a copper circuit is formed on the surface of the printed wiring board (not shown) that is in contact with the prepreg or the insulating film 4, a primer is also applied on the printed wiring board and laminated.

As described above, according to the present invention, after a primer is applied on the surface of a printed wiring board on which a copper circuit is formed, the printed wiring board may be laminated via an insulating film or a prepreg. Further, the adhesion between the copper circuit and the insulating film or the prepreg can be increased without a wet treatment as in the conventional blackening treatment.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples, and may be modified as appropriate without departing from the scope of the invention. It can be implemented by

(Preparation of Primer) Ethylene acrylic acid (acrylic acid content 20% by weight, weight average molecular weight 200
00, trade name "PR-5980", manufactured by Dow Chemical Company)
Is neutralized with ammonia so that the neutralization rate becomes 70%,
An aqueous dispersion having a nonvolatile content of 10% by weight was prepared and used as a primer of Example 1.

Ethylene acrylic acid (acrylic acid content 1
0% by weight, weight average molecular weight 20,000, trade name "PR-
3460 ", manufactured by Dow Chemical Company), xylene and DMF
Diluted with a mixed solvent (7: 3) of the
Was used as the primer of Example 2.

(Evaluation of Adhesion) Using the primers of Examples 1 and 2, a copper foil and an insulating film were adhered to each other.
The adhesion of each primer was evaluated.

As shown in FIG. 2, a galvanized plate was used as the support plate 10. An epoxy adhesive 11 was applied on the support plate 10, and an insulating film 12 was formed thereon. The insulating film 12 is PR5000 (manufactured by Nippon Paint Co., Ltd.)
Was dry-laminated so as to have a dry film thickness of 40 μm, and was cured by heating at 90 ° C. for 30 minutes.

Next, the primer of Example 1 or 2 was coated on a copper foil (thickness: 36 μm) with a dry film thickness of 3 μm.
And cured by heating at 80 ° C. for 30 minutes.

Since the primer of Example 2 has a high viscosity, the material to be coated and the primer are 80
In this state, the mixture was applied using a bar coater, and after being applied, it was cured by placing it in an oven at 80 ° C. for 30 minutes.

Next, as described above, the primer layer 13
Is placed on the insulating film 12 with the primer layer 13 facing down, pressed and bonded at a pressure of 20 N / cm ² , and then heated at 175 ° C. for 2 hours. . By this heating, the insulating film 12 and the primer layer 1
For No. 3, the second heat curing was performed.

Next, as shown in FIG. 3 (plan view), both side portions of the copper foil 14 on the primer layer 13 were removed, and the width of the copper foil portion 14 was set to 10 mm. Next, the end of the copper foil portion 14 was pulled up in the 90 ° direction (upward), and the peel strength was measured. The peel strength was measured by JPCA-BU01-1998, which is a standard of the Japan Printed Circuit Industry Association (JPCA).
Of the conductive layer was measured in accordance with the measuring method of peel strength (peel strength).

For comparison, in FIG. 2, a film was prepared in which the copper foil 14 was directly placed on the insulating film 12 without forming the primer layer 13 on the insulating film 12, and the peel strength was reduced in the same manner as described above. It was measured (Comparative Example 1). Table 1 shows the measurement results of the peel strength.

[0024]

[Table 1]

As shown in Table 1, Examples 1 and 2
It can be seen that the use of the primer (1) increases the peel strength and enhances the adhesion between the insulating film and the copper foil. The peel strength is required to be at least 10 N / cm or more in view of the peel strength of the copper plating and the insulating film. When the primers of Example 1 and Example 2 are used, a peel strength of 10 N / cm or more can be obtained.

[0026]

According to the present invention, the adhesion between the copper circuit and the insulating film or the prepreg can be improved by merely applying the copper circuit without performing the blackening treatment of the copper circuit surface or the wet etching roughening treatment of the copper. Primer composition.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view for explaining a state in which a printed wiring board and an insulating film or a prepreg are laminated using a primer composition of the present invention.

FIG. 2 is a sectional view for explaining a peel strength measurement test in an example of the present invention.

FIG. 3 is a plan view for explaining a peel strength measurement test in an example of the present invention.

[Explanation of symbols]

 1: Printed wiring board 2: Copper circuit 3: Primer 4: Insulating film or prepreg

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (reference) C09D 133/02 C09D 133/02 H05K 3/38 H05K 3/38 EF term (reference) 4J038 CB061 CB071 CB091 GA06 GA08 GA09 NA12 PB09 PC02 PC08 5E343 AA02 AA12 AA13 AA17 AA38 BB05 BB24 BB67 CC01 EE22 FF01 GG04 5E346 AA05 AA06 AA12 AA16 AA22 AA32 AA51 CC08 CC32 CC41 DD02 DD03 EE09 EE12 EE13 EE18 EE13 GG18 5G

Claims (4)

[Claims] When a printed wiring board having a copper circuit formed on its surface is laminated via an insulating film or prepreg, a primer composition is applied to increase the adhesion between the copper circuit and the insulating film or prepreg. A primer composition for a multilayer printed wiring board, comprising an olefin copolymer resin having a carboxyl group in a side chain. 2. The primer composition for a multilayer printed wiring board according to claim 1, wherein a carboxyl group of the olefin copolymer resin is neutralized and contained. 3. The primer composition for a multilayer printed wiring board according to claim 1, wherein the olefin copolymer resin is an ethylene acrylic acid copolymer resin. 4. The primer composition for a multilayer printed wiring board according to claim 3, wherein the acrylic acid content of the ethylene acrylic acid copolymer resin is 2 to 50% by weight.