JPH09205280A - Metal foil with resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a resin in a semi-hardened state from coming loose and falling without lowering the resin characteristic of a copper foil with a resin for multilayer molding by a method in which a cross-linking rubber whose particle size is at a specific value or lower is contained in a resin for insulation. SOLUTION: A metal foil with a resin is used in such a way that a metal foil such as copper, aluminum or the like is coated with a resin for insulation. As the resin for insulation, a thermosetting resin is used. Then, by using the resin for insulation, an insulating layer is formed on the metal foil. The resin is dissolved in an amine-based solvent such as DMF or the like or a ketone- based solvent such as MC, PC or the like so as to easily coat the metal foil, and the resin is liquefied so as to be used as a resin varnish. In addition, a cross-linking rubber whose particle size is at 0.5μm or lower or a high-order aggregate by the second order, the third order or higher of cross-linking rubber particles whose particle size is at 0.5μm or lower is added to the resin varnish, and the greater part of it is dispersed in a resin-dissolving liquid as a first-order dispersion substance. Thereby, the crack of the resin can be reduced.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a material for a multilayer printed wiring board, and more particularly to a metal foil with a resin for multilayer molding.

[0002]

2. Description of the Related Art Conventionally, there is known a method of manufacturing a multilayer printed wiring board by laminating and molding a resin-coated metal foil obtained by applying an insulating resin and then drying and semi-curing it on an inner layer substrate on which a wiring pattern is formed. Has been. In this metal foil with resin,
As shown in Japanese Patent Laid-Open No. 5-206647, a polyimide resin, an epoxy resin, a fluorine resin, or the like is generally used as the applied insulating resin.

As a method for producing the resin-coated metal foil,
An uncured or low molecular weight resin is dissolved or dispersed in a solvent to form a liquid, or a low molecular weight resin that is liquid at room temperature is selected, and these resins are applied to a metal foil and then dried to cure or , It is manufactured by advancing curing to a semi-cured state.

The resin-coated metal foil obtained as described above is subjected to etching, for example, on a double-sided copper-clad laminate to form an inner layer substrate, and further, a treatment of the inner layer circuit copper foil surface called blackening treatment. Then, the resin layer is placed on both sides of the inner layer substrate so that the resin surface faces the inner side, and heating and pressurization are performed to form a multilayer structure.
In addition, one or more prepregs of glass cloth base material are superposed between the resin-coated copper foil and the inner layer substrate, and heated and pressed to perform multi-layer molding.

However, in the above case, the resin-coated metal foil used in the process of manufacturing the multilayer printed wiring board causes resin cracking and resin peeling off during handling, such as when superposed on the inner layer substrate. As a result, defective interlayer insulation of the obtained multilayer printed wiring board and radish defects due to peeled off resin occur.

As a method for improving the above-mentioned points, it is disclosed in JP-A-58-83014 and JP-A-59-138254 that a cross-linking rubber is mixed with an insulating resin applied to a metal foil in an appropriate amount. It is shown.

However, according to this method, peeling of the resin is prevented, and at the same time, the glass transition point (hereinafter, referred to as T
There is a problem in that g) is lowered or the heat resistance of the resin itself is also lowered.

Further, in Japanese Patent Laid-Open No. 4-202350,
By dispersing fine crosslinked rubber in epoxy resin,
We propose to improve impact resistance after curing epoxy resin.

Based on the above-mentioned proposal of the method for improving the characteristics of the cured epoxy resin, the peeling of the resin in the semi-cured state of the metal foil with resin is further improved and the heat resistance after curing of the resin is not lowered, and the peeling is achieved. There is a demand for new resin-coated metal foils that take measures to prevent them from falling off.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and prevents the resin from peeling off in a semi-cured state without deteriorating the resin characteristics of the copper foil with a resin for multilayer molding. It is intended to provide a resin-coated copper foil which is prevented.

[0011]

A resin-coated metal foil according to claim 1 of the present invention is an inner layer having a circuit pattern formed by applying an insulating resin in a B-stage state to the metal foil to form an insulating layer. A resin-coated metal foil that is laminated on a substrate for forming a multilayer printed wiring board is characterized in that the insulating resin contains a crosslinked rubber having a particle diameter of 0.5 μm or less.

In the resin-coated metal foil according to claim 2 of the present invention, the crosslinked rubber is 0.2 phr with respect to the insulating resin.
It is characterized in that it is contained at 10 phr or less.

A resin-coated metal foil according to a third aspect of the present invention is formed by applying an insulating resin in a B-stage state to a metal foil to form an insulating layer, and laminating the resin layer on an inner layer substrate having a circuit pattern. A resin-coated metal foil that constitutes a multilayer printed wiring board is characterized in that the insulating resin contains a thermoplastic epoxy resin having a glass transition point of 90 ° C. or higher.

A resin-coated metal foil according to a fourth aspect of the present invention is characterized in that the thermoplastic epoxy resin is contained in the insulating resin in an amount of 1 phr or more and 40 phr or less.

The resin-coated metal foil according to claim 5 of the present invention comprises a first resin layer in which the insulating resin applied to the resin-coated metal foil is softened at high temperature and a second resin layer which is melted at low temperature. It is characterized by being formed.

According to a sixth aspect of the present invention, there is provided a resin-coated metal foil, wherein the resin layer formed by applying the resin-coated metal foil is formed in multiple layers, and a resin having a melting point sequentially higher than a side adjacent to the copper foil is used. It is characterized by applying.

The resin-coated metal foil according to claim 7 of the present invention is characterized in that a copper foil is used as the metal foil of the resin-coated metal foil.

Thus, by containing the crosslinked rubber having a particle diameter of 0.5 μm or less in the insulating resin, it has elasticity in a semi-cured state and can prevent the resin from peeling off.

Further, the copper foil with resin for multi-layer molding of the invention according to claims 3 to 4 and 5 to 6 is characterized in that the insulating resin contains a thermoplastic epoxy resin having a glass transition point of 90 ° C. or higher. This makes it possible to prevent the resin from peeling off in the semi-cured state and maintain the resin characteristics after curing.

The present invention will be described in detail below.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION As the resin-coated metal foil of the present invention, a metal foil such as copper or aluminum coated with an insulating resin is used.

A thermosetting resin is used as the insulating resin applied to the metal foil. For example, a thermosetting resin such as an epoxy resin, a polyimide resin, a polyester resin, a phenol resin, or a polyphenylene oxide-containing thermosetting resin is used. Is used.

An insulating layer is formed on the metal foil by using the above-mentioned insulating resin. D is used so that it can be easily applied on the metal foil.
Amine-based solvents such as MF and DMAC, MC, PC, ME
It is dissolved in a ketone solvent such as K and liquefied to be used as a resin varnish. Further, if necessary, a filler such as an inorganic powder or fibers can be dispersed at the time of dissolution in a solvent.

The resin varnish has a particle size of 0.5 μm.
m or less crosslinked rubber, or a secondary or tertiary or higher order aggregate of crosslinked rubber particles having a particle diameter of 0.5 μm or less,
It is preferable to disperse most of it in a resin solution or a resin melt as a primary dispersion because cracking of the resin is reduced. Further, the crosslinked rubber is 0.2 phr or more and 10 ph
When it is contained at r or less, Tg is not lowered and cracking of the resin is reduced, which is preferable.

The cross-linked rubber as described above has a particle size of 0.5 μm or less, but preferably has a particle size of 0.02 μm or more in order to prevent resin cracking.

There are no particular restrictions on the constituents of the crosslinked rubber, but SBR, BR, IR, EP
M, EPDM, NBR, CR, butyl rubber, urethane rubber, silicone rubber, polysulfide rubber, hydrogenated nitrile rubber, polyether special rubber, fluororubber, tetrafluoroethylene propylene rubber, acrylic rubber, epichlorohydrin rubber, propylene Those having a chemical composition such as oxide rubber, ethylene vinyl acetate copolymer, ethylene acrylic rubber, norporne rubber, and thermoplastic elastomer are used.

Further, in place of the crosslinked rubber, a thermoplastic epoxy resin having a glass transition point of 90 ° C. or higher is dispersed in a resin solution or a resin melt of the insulating resin to form a resin varnish. Is preferable because it reduces Furthermore, 1 part of the thermoplastic epoxy resin is added to the thermosetting resin.
It is preferable for the content to be not less than phr and not more than 40 phr because Tg is not lowered and cracking of the resin is reduced. Further, when the glass transition point is 90 ° C. or higher, the content can be increased without lowering the glass transition point after molding.
In particular, the glass transition point of this thermoplastic epoxy resin is 11
When the temperature is 0 ° C or higher, the effect becomes remarkable. The upper limit of the glass transition point may be within the range of existing thermoplastic epoxy resins.

The thermoplastic epoxy resin is not particularly limited, but a phenoxy resin is used in the examples of the present invention.

As a method of applying the insulating resin to the metal foil, a comma coater, a transfer coater, a curtain coater or the like is used, and the liquid insulating resin is applied to the metal foil, and further, it is continuous or discontinuous. Then, it is heat-dried and semi-cured to form a B-staged insulating layer. The insulating layer used is at least one layer, but it is also preferable to apply a plurality of layers.

For example, the insulating resin applied to the resin-coated metal foil is formed of a first resin layer that softens at high temperature and a second resin layer that melts at low temperature, and the first resin layer is the metal foil side. When it is formed, the second resin layer that is in contact with the inner layer substrate at the time of laminate molding is first melted, and the adhesion with the inner layer substrate can be improved. In addition, it is preferable that a plurality of insulating layers are applied by changing the melting point of each resin layer, and when the melting point becomes higher toward the metal foil side, the resin is used for the inner layer when forming a multilayer printed wiring board. It is preferable because it easily flows on the substrate. Here, it is preferable that the resin layer in contact with the metal foil does not melt at the molding temperature and is softened in order to secure its thickness. It is also equipped with a hardening that keeps the surface roughness constant.

The above-mentioned resin-coated metal foil is used as a material for a multilayer printed wiring board. For example, it is superposed on an inner layer substrate having a wiring pattern formed on a glass epoxy copper clad laminate, and is heated and pressed. After multi-layer molding, the outer layer circuit is further formed to obtain a multi-layer printed wiring board.

[0032]

EXAMPLES AND COMPARATIVE EXAMPLES The present invention will be described below based on Examples and Comparative Examples, but these Examples do not limit the present invention.

First, a wiring pattern is formed on one surface of a FR-4 type double-sided copper clad laminate (laminate thickness 1.0 mm, copper foil thickness 35 μm), and copper foil is formed on the other surface. The entire surface was removed by etching to prepare an inner layer substrate having a wiring pattern formed thereon, and the surface of the wiring pattern was subjected to a surface treatment called blackening treatment.

In addition, an electrolytic copper foil for electric use (GT-18 μm, manufactured by Furukawa Circuit Co., Ltd.) having a thickness of 18 μm was used as an insulating resin, and a FR containing bisphenol A type epoxy resin, which is a thermosetting resin, and dicyandiamide as main components. -4 type epoxy resin varnish used for the production of laminated plate is coated with a comma coater so that the thickness after drying becomes 50 μm, and dried at 130 ° C. for 20 minutes to be semi-cured. To obtain a resin-coated copper foil.

The resin varnish used above was used in the following Examples and Comparative Examples to form a resin-coated copper foil.

As a method of dispersing the resin varnish,
A commonly used stirrer was used, and in the examples and comparative examples of the present invention, the mixture was mixed and dispersed for 90 minutes by "Homomixer" manufactured by Tokushu Kika Kogyo Co., Ltd.

A phenoxy resin was used as the thermoplastic epoxy resin contained in the insulating resin. (Example 1) A fine particle crosslinked rubber (XER-91 manufactured by Japan Synthetic Rubber Co., Ltd.) was dispersed in the epoxy resin varnish in an amount of 0.2 phr with respect to the resin content in the epoxy resin varnish. (Example 2) A fine particle crosslinked rubber (XER-91 manufactured by Japan Synthetic Rubber Co., Ltd.) was dispersed in the epoxy resin varnish at 0.5 phr with respect to the resin content in the epoxy resin varnish. (Example 3) Fine particle crosslinked rubber (XER-91 manufactured by Japan Synthetic Rubber Co., Ltd.) was dispersed in the epoxy resin varnish at 1.0 phr with respect to the resin content in the epoxy resin varnish. (Example 4) A fine particle crosslinked rubber (XER-91 manufactured by Japan Synthetic Rubber Co., Ltd.) was dispersed in the epoxy resin varnish at 3.0 phr with respect to the resin content in the epoxy resin varnish. (Example 5) A fine particle crosslinked rubber (XER-91 manufactured by Japan Synthetic Rubber Co., Ltd.) was dispersed in the epoxy resin varnish at 10.0 phr with respect to the resin content in the epoxy resin varnish. Example 6 A phenoxy resin (YP50 manufactured by Tohto Kasei Co., Ltd.) was dispersed in the epoxy resin varnish in an amount of 1.2 phr with respect to the resin content in the epoxy resin varnish. Example 7 A phenoxy resin (YPS30, manufactured by Tohto Kasei Co., Ltd.) was dispersed in the epoxy resin varnish at 5.0 phr with respect to the resin content in the epoxy resin varnish. (Example 8) A phenoxy resin (YPB40 manufactured by Tohto Kasei Co., Ltd.) was dispersed in the epoxy resin varnish at 15 phr with respect to the resin component in the epoxy resin varnish. (Example 9) A phenoxy resin (YPS30, manufactured by Tohto Kasei Co., Ltd.) was dispersed in the epoxy resin varnish at 28 phr with respect to the resin component in the epoxy resin varnish. (Comparative Example 1) The epoxy resin varnish was applied as it was in a normal state without compounding any rubber component and phenoxy resin component. Comparative Example 2 A crosslinked rubber (HYCARCTBN-1300 × 8 manufactured by Ube Industries, Ltd.) was dispersed in the epoxy resin varnish in an amount of 3.0 phr with respect to the resin component in the epoxy resin varnish. (Comparative Example 3) Fine particle crosslinked rubber (XER-91 manufactured by Japan Synthetic Rubber Co., Ltd.) was dispersed in the epoxy resin varnish at 0.1 phr with respect to the resin content in the epoxy resin varnish. (Comparative Example 4) Fine particle crosslinked rubber (XER-91 manufactured by Japan Synthetic Rubber Co., Ltd.) was dispersed in the epoxy resin varnish at 15.0 phr with respect to the resin content in the epoxy resin varnish. Comparative Example 5 A phenoxy resin (YP40 manufactured by Tohto Kasei Co., Ltd.) was dispersed in the epoxy resin varnish in an amount of 18 phr with respect to the resin content in the epoxy resin varnish. Comparative Example 6 A phenoxy resin (YPS30 manufactured by Tohto Kasei Co., Ltd.) was dispersed in the epoxy resin varnish at 0.8 phr with respect to the resin content in the epoxy resin varnish. Comparative Example 7 A phenoxy resin (YPB40 manufactured by Tohto Kasei Co., Ltd.) was dispersed in the epoxy resin varnish in an amount of 35 phr with respect to the resin content in the epoxy resin varnish.

The resin-coated copper foil obtained by using the epoxy resin varnish as described above faces the resin-formed copper foil on the circuit forming surface of the inner layer substrate on which the wiring pattern is formed. Then, the pressed body was placed, and the pressed body was further sandwiched between stainless plates, and multilayer molding was performed under the following conditions.

Under the conditions of heating temperature 100 ° C. and pressure 5 kg / cm ² , the resin layer of the copper foil with resin melted and flowed to embed the inner layer circuit pattern, and then at 170 ° C., 30 kg / cm ²
It heated and pressurized on the conditions of 120 minutes.

The multilayer board molded under the above conditions was further subjected to outer layer circuit formation and finishing to obtain a multilayer printed wiring board.

[0041]

[Evaluation] The above Examples 1 to 9 and Comparative Examples 1 to 7
The resin-coated copper foil and the multilayer printed wiring board obtained in 1. were evaluated and confirmed as follows. (Bending test) Diameter 2 for each resin-coated copper foil
A 180-degree bending test was carried out by a bending tester of mm, and those without cracks were evaluated as OK, and those with cracks were evaluated as NG, and the crackability of the resin in the semi-cured state was evaluated. (Dispersion state of crosslinked rubber) After cutting a part of each resin-coated copper foil, the cross section was polished and observed by SEM to determine the dispersion size of the crosslinked rubber component present in the resin in the semi-cured state. Observed and evaluated. (Resin Tg after molding and curing) The resin Tg (glass transition temperature) after molding and curing using a multilayer printed wiring board is manufactured by Rigaku Corporation TM
A was measured under the condition of 10 ° C./min. (Defective Dacon) The frequency of occurrence of defective Dacon due to the resin peeled off from the resin-coated copper foil during molding was evaluated by visually observing the surface of the multilayered multilayer board. (Dissolution resistance) The multilayer printed wiring board was immersed in trichlene as an example of an organic solvent and boiled for 10 minutes to visually evaluate the dissolution resistance. The one not dissolved was OK, and the one not dissolved was NG.

In this way, the stability of the resin after molding and curing during the processing of the multilayer printed wiring board was examined.

The results obtained above are shown in Tables 1 and 2.

[0044]

[Table 1]

[0045]

[Table 2]

[0046]

According to the resin-coated metal foil of the present invention, the insulating resin forming the resin-coated metal foil has an ultrafine particle crosslinked rubber of 0.5 μm or less, or a thermoplastic epoxy resin having a glass transition point of 90 ° C. or more. It is possible to improve the insulation reliability of the product by preventing the resin from cracking or peeling off in the semi-cured state by lowering the heat resistance after curing by dispersing. Further, by preventing the resin from cracking or peeling off in the semi-cured state, it is possible to remarkably reduce the occurrence of radish defects in the manufacturing process.

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[Procedure amendment]

[Submission date] April 1, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 3

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0001

[Correction method] Change

[Correction contents]

[0001]

TECHNICAL FIELD The present invention relates to a material for a multilayer printed wiring board, and more particularly to a metal foil with a resin for multilayer molding.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction contents]

As described above, since the insulating resin contains the crosslinked rubber having a particle diameter of 0.5 μm or less, it has flexibility in a semi-cured state and can prevent the resin from peeling off.
Moreover, the glass transition temperature after molding is not lowered.

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0024

[Correction method] Change

[Correction contents]

The resin varnish has a particle size of 0.5 μm.
m or less crosslinked rubber, or a secondary or tertiary or higher order aggregate of crosslinked rubber particles having a particle diameter of 0.5 μm or less,
It is preferable to disperse most of it in a resin solution or a resin melt as a primary dispersion because cracking of the resin is reduced. Further, the crosslinked rubber is 0.2 phr or more and 10 ph
When the content is less than r, the glass transition temperature after molding is not lowered and cracking of the resin is reduced, which is preferable.

Claims (7)

[Claims] 1. A metal foil with resin for forming a multilayer printed wiring board by applying an insulating resin in a B-stage state to a metal foil to form an insulating layer, and laminating and forming the insulating layer on a circuit board-formed inner layer substrate. In the above, the insulating resin has a particle size of 0.
A metal foil with a resin, which contains a crosslinked rubber of 5 μm or less. 2. The resin-coated metal foil according to claim 1, wherein the crosslinked rubber is contained in the insulating resin in an amount of 0.2 phr or more and 10 phr or less. 3. A metal foil with resin for forming a multilayer printed wiring board by applying an insulating resin in a B-stage state to a metal foil to form an insulating layer and laminate-molding it on an inner layer substrate having a circuit pattern formed thereon. 3. The resin-coated metal foil according to claim 1, wherein the insulating resin contains a thermoplastic epoxy resin having a glass transition point of 90 ° C. or higher. 4. The metal foil with resin according to claim 3, wherein the thermoplastic epoxy resin is contained in the insulating resin in an amount of 1 phr or more and 40 phr or less. 5. The first resin layer in which the insulating resin applied to the resin-coated metal foil is softened at a high temperature, and the second resin layer which is melted at a low temperature are formed. The resin-coated metal foil according to any one of claims 1 to 4. 6. The resin layer formed by applying to the resin-coated metal foil is formed in multiple layers, and the resin having a higher melting point is applied sequentially from the side adjacent to the copper foil. The resin-coated metal foil according to any one of claims 1 to 7. 7. The metal foil with resin according to any one of claims 1 to 6, wherein the metal foil of the metal foil with resin is a copper foil.