JPH09260856A - Multilayered copper-clad laminated board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayered copper-clad laminated board superior in moisture absorption, a heat resistance and a shelf life of prepregs, without lowering the Cu-foil adhesion strength. SOLUTION: A multilayered Cu-clad laminated board is formed by stacking an inner layer circuit board, epoxy resin (1) compd.-impregnated prepreg and epoxy resin (2)-coated Cu foil and characterized as well as a prepreg for multilayer structures, as follows. The resin compd. (1) contains an inorg. filler of a mean grain size of 3μm or less 3-40wt.%, treated with a silane coupling agent. The resin compd. (2) contains an inorg. filler of a mean grain size of 5μm or more 3-25wt.%, treated with a silane coupling agent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer copper clad laminate having excellent heat resistance against moisture absorption.

[0002]

2. Description of the Related Art In recent years, the development of electronic equipment has been remarkable, and the use of copper clad laminates has become diverse, and the density of wiring and the use of multilayer boards are increasing. A problem with the copper clad laminates used for these is that soldering causes measling and swelling. For this reason, attempts have been made to improve the resin composition, but in particular, in a multilayer copper-clad laminate having an inner layer circuit, measling and the like are likely to occur and there is a drawback that the moisture absorption heat resistance is poor.

[0003]

In order to improve heat resistance after moisture absorption, a method of adding an inorganic filler to an epoxy resin composition which is impregnated into a base material and dried has been studied, but the effect is recognized. On the other hand, since the peeling strength of the copper foil is reduced, the addition amount of the filler is limited, and a large effect cannot be achieved.

In order to improve the adhesion between the inorganic filler and the epoxy resin, addition of a silane coupling agent has been studied, but it is applied uniformly on the surface of the inorganic filler ( In particular, as an inorganic filler having a hollow porous structure), it was incomplete and a great effect was not obtained.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a multi-layer copper-clad laminate excellent in heat resistance to moisture absorption and storage stability of prepreg without lowering the peeling strength of the copper foil. To do.

[0006]

Means for Solving the Problems As a result of intensive studies aimed at achieving the above-mentioned object, the present inventor has included inorganic fillers having different average particle diameters, which are uniformly surface-treated with a silane coupling agent. The inventors have found that the above objects can be achieved by using an epoxy resin composition as an adhesive resin for copper foil and an impregnating resin for prepreg, and have completed the present invention.

That is, according to the present invention, the inner layer circuit board, the prepreg impregnated with the epoxy resin composition (1) and dried, and the copper foil coated with the epoxy resin composition (2) and dried are laminated and heated and pressed. In the multilayer copper-clad laminate, the epoxy resin composition (1) contains an inorganic filler having an average particle size of 3 μm or less, which is uniformly treated on the entire surface with a silane coupling agent, to the entire composition. The epoxy resin composition (2) is a composition containing 3 to 40% by weight.
However, it is a composition containing an inorganic filler having an average particle size of 5 μm or more uniformly treated on the entire surface with a silane coupling agent in a proportion of 3 to 25% by weight with respect to the entire composition. It is a characteristic multilayer copper clad laminate. Further, it is a multi-layer prepreg used for the above-mentioned multi-layer copper-clad laminate.

Hereinafter, the present invention will be described in detail.

Epoxy resin composition used in the present invention (1)
Both (2) and (2) contain an epoxy resin and an inorganic filler treated with a silane-based coupling agent. The epoxy resin used here is 2 per molecule.
Any compound having at least one epoxy group may be used, and it is not particularly limited and can be widely used. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolac type epoxy resin, glycidyl ether type epoxy resin, glycidyl amine type epoxy resin, alicyclic epoxy resin, heterocyclic epoxy resin, halogenated epoxy resin and the like can be mentioned. These can be used alone or in admixture of two or more.

The inorganic filler is usually used as an inorganic filler, and is not particularly limited and can be widely used. As specific inorganic fillers, for example, hollow porous ones are synthetic silica, non-hollow porous ones are natural silica, fused silica, silica such as amorphous silica, white carbon, titanium white, aerosil, clay, talc, Examples thereof include fine glass powders such as wollastonite, natural mica, synthetic mica, kaolin, aluminum hydroxide, alumina, and E glass / A glass / C glass.

The average particle size of the inorganic filler is preferably 30 μm or less. If the average particle size exceeds 30 μm, the property balance between heat resistance against moisture absorption and peeling strength becomes unfavorable, which is not preferable.

The silane coupling agent is not particularly limited, and those usually used as coupling agents can be used. Specific examples include silane coupling agents having a functional group such as an alkoxy group, a chloropropyl group, a γ-aminopropyl group, and a glycidyloxypropyl group. These are used alone or in combination of two or more. can do. As a method of adding the silane coupling agent, the inorganic filler is preliminarily treated, and it is preferable to uniformly treat the entire surface of the inorganic filler with a solvent. The solvent is a hollow porous or general type by dissolving the coupling agent in an amount of 0.1 to 10% by weight with respect to the inorganic filler, mixing the solution with the inorganic filler and stirring to volatilize the solvent. It is possible to uniformly treat the entire surface of the inorganic filler with the silane coupling agent.

The epoxy resin composition used in the present invention contains an epoxy resin and an inorganic filler treated with a silane coupling agent, but other additives may be used as long as they do not deviate from the object of the present invention. Ingredients such as a curing accelerator can be added and compounded. An epoxy resin composition can be manufactured by adding these components and mixing with stirring.

The epoxy resin composition is thus obtained, but the epoxy resin composition (1) impregnated and dried on the glass substrate and the epoxy resin composition (2) coated and dried on the copper foil are different resin compositions. I will explain it using.

The epoxy resin composition (1) to be impregnated into a glass substrate and dried is preferably an inorganic filler having an average particle size of 3 μm or less, which is preliminarily uniformly treated with a silane coupling agent on the entire surface thereof. desirable. If the average particle size exceeds 3 μm, the effect on moisture absorption heat resistance is insufficient, which is not preferable. The compounding ratio of the inorganic filler is 3 to 40 with respect to the entire resin composition.
It is desirable to mix such that it is contained by weight.
If the content of the inorganic filler is less than 3% by weight, the heat resistance against moisture absorption is insufficient, and if it exceeds 40% by weight, the formability of the laminate is adversely affected, which is not preferable.

For the epoxy resin composition (2) to be applied and dried on the copper foil, an inorganic filler having an average particle size of 5 μm or more, which has been uniformly treated with a silane coupling agent on the entire surface in advance, is used. Is desirable. If the average particle size is less than 5 μm, the peeling strength of the copper foil decreases, which is not preferable. It is desirable to mix the inorganic filler so that it is contained in an amount of 3 to 25% by weight based on the entire resin composition. If the content of the inorganic filler is less than 3% by weight, the effect of heat resistance against moisture absorption is insufficient, and if it exceeds 25% by weight, the peeling strength of the copper foil decreases, which is not preferable.

The prepreg used in the present invention means that a glass substrate is impregnated with the above-mentioned epoxy resin composition (1), dried, and
A semi-cured product can be used. The glass substrate used here is not particularly limited,
It is possible to use glass woven cloth, glass non-woven cloth, and glass paper made of E glass and D glass that are commonly used.

The copper foil used in the present invention is an ordinary copper foil obtained by coating and drying the above-mentioned epoxy resin composition (2). The copper foil may be either a rolled copper foil or an electrolytic copper foil, and it is not particularly limited as long as it is usually used for a laminated plate.

As the inner layer circuit board used in the present invention, the above-mentioned copper foils are superposed on at least one surface of a plurality of the above-mentioned prepregs and integrally molded under heat and pressure to form a copper-clad laminate.
It can be made by forming a circuit. This inner layer circuit board is used after being subjected to normal blackening treatment in order to improve the adhesion with the prepreg. It is possible to produce a multilayer copper clad laminate by superposing the above-mentioned prepreg and copper foil on both surfaces of this inner layer circuit board and integrally molding them by heating and pressing.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. In the following Examples and Comparative Examples, “parts” means “parts by weight”.

Example 68 parts of brominated epoxy resin (epoxy equivalent 480), cresol novolac epoxy resin (epoxy equivalent 210) 7
Part, and H-containing synthetic silica as a hollow porous inorganic filler that has been uniformly subjected to silane coupling treatment in advance.
31 (trade name of Asahi Glass Co., Ltd., average particle size 3 μm) 25 parts, dicyandiamide 3 parts, 2-ethyl-4-methylimidazole
0.1 part, 60 parts of acetone and 20 parts of dimethylformamide were added and stirred and dissolved to prepare a varnish of the epoxy resin composition. This varnish was applied to a woven glass cloth having a thickness of 180 μm, impregnated and dried at a temperature of 160 ° C. to prepare a prepreg (I) having a resin content of 45%.

Further, brominated epoxy resin (epoxy equivalent
480) 83 parts, cresol novolac epoxy resin (epoxy equivalent 210) 7 parts, and aluminum hydroxide H-31 (Showa Denko brand name, average particle size 18 μm) 10 which has been uniformly subjected to silane coupling treatment in advance. Part, dicyandiamide 3 parts, 2-ethyl-4-methylimidazole 0.1 part
Parts, 60 parts of acetone and 20 parts of dimethylformamide were added and stirred and dissolved to prepare a varnish of the epoxy resin composition. Apply this varnish to copper foil with a thickness of 18 μm, 160 ℃
The resin-coated copper foil (I) having a resin thickness of 15 μm was obtained by drying at the temperature of.

Brominated epoxy resin (epoxy equivalent 480)
93 parts, and 7 parts of cresol novolac epoxy resin (epoxy amount 210), 3 parts of dicyandiamide, 2-ethyl
-4-Methylimidazole (0.1 part), acetone (60 parts) and dimethylformamide (20 parts) were added, and the mixture was stirred and dissolved to prepare a varnish of the epoxy resin composition. Thick this varnish
A prepreg (II) having a resin content of 45% was prepared by coating and impregnating a 180 μm glass woven fabric and drying at a temperature of 160 ° C.

Five prepregs (II) were stacked, 70 μm copper foil was placed on both sides of the prepreg (II), and heat-pressed to form a copper-clad laminate. A circuit is formed on this copper-clad laminate to perform blackening treatment to make an inner-layer circuit board (I), prepregs (I) are laid on both sides of each, and then a resin-coated copper foil (I) is placed on the outside. ) Were laminated one by one and integrally molded by heating and pressing to produce a 4-layer copper clad laminate.

Comparative Example 1 78 parts of brominated epoxy resin (epoxy equivalent 480), cresol novolac epoxy resin (epoxy equivalent 210) 7
Part, and H-containing synthetic silica as a hollow porous inorganic filler that has been uniformly subjected to silane coupling treatment in advance.
31 (trade name of Asahi Glass Co., Ltd., average particle size 3 μm) 15 parts, dicyandiamide 3 parts, 2-ethyl-4-methylimidazole
0.1 part, 60 parts of acetone and 20 parts of dimethylformamide were added and stirred and dissolved to prepare a varnish of the epoxy resin composition. This varnish was applied on a woven glass cloth having a thickness of 180 μm, impregnated and dried at a temperature of 160 ° C. to prepare a prepreg (III) having a resin content of 45%.

The inner layer circuit board (I) used in the examples was laminated with prepregs (III) one by one on both sides, and then copper foils were overlaid one by one on the outside thereof and integrally molded by heating and pressing. A 4-layer copper clad laminate was produced.

Comparative Example 2 Prepregs (I) were laminated on both sides of the inner layer circuit board (I) used in the examples one by one, and then copper foils were laminated one by one on the outer side of the prepregs (I) for heat and pressure integration. Molded to produce a 4-layer copper clad laminate.

Comparative Example 3 A prepreg (II) was superposed on both sides of the inner layer circuit board (I) used in the examples one by one, and then a copper foil was superposed one by one on the outer side of the inner prepreg (II) for heat and pressure integration. Molded to produce a 4-layer copper clad laminate.

The storage stability of the prepregs produced in Examples and Comparative Examples 1 to 3, the moisture absorption heat resistance of the 4-layer copper clad laminate, and the peel strength of the copper foil were tested. The results are shown in Table 1. However, the present invention showed excellent characteristics and balance, and the effects of the present invention could be confirmed.

[0030]

[Table 1] * 1: The prepreg was stored in a 40 ° C incubator for 30 days, and the gel time retention rate after storage was calculated relative to the initial gel time value. * 2: After etching the outermost copper foil of a 4-layer copper-clad laminate, cut it into 50 mm x 50 mm pieces, and wash 4 pieces, and then dry at 80 ° C for about 1 hour to obtain a sample. The samples were treated with PCT at a temperature of 120 ° C for 4 hours, immersed in a solder bath at 260 ° C for 30 seconds, and observed for blisters. The results of 4 samples were also shown. Evaluation Criteria A: No change, B: Change, C: Mease ring occurred, D: Small blisters occurred.

[0031]

As is apparent from the above description and Table 1, the multilayer copper clad laminate of the present invention has excellent heat resistance to moisture absorption and storage stability of prepreg without lowering the peeling strength of the copper foil. , Reliable.

Claims (2)

[Claims] 1. An inner layer circuit board, an epoxy resin composition (1)
In a multilayer copper-clad laminate in which a prepreg impregnated with and dried and a copper foil coated with the epoxy resin composition (2) and dried are stacked and heat-pressed, the epoxy resin composition (1) is applied to the entire surface. A composition containing an inorganic filler having an average particle diameter of 3 μm or less uniformly treated with a silane coupling agent in a proportion of 3 to 40% by weight based on the entire composition, wherein the epoxy resin composition ( 2) has an average particle size of 5 μ, where the entire surface is uniformly treated with a silane coupling agent.
A multi-layer copper-clad laminate, which is a composition containing 3 to 25 wt% of an inorganic filler of m or more with respect to the entire composition. 2. An inorganic filler having an average particle size of 3 μm or less, which is obtained by uniformly treating a glass substrate with a silane coupling agent, in a proportion of 3 to 40% by weight based on the entire composition. A multi-layer prepreg, which is obtained by impregnating and drying the contained epoxy resin composition.