JPH10178275A - Composite sheet for multilayered wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent surface contamination of a metal foil coated with resin for a multilayered wiring board by covering the thermosetting resin surface of the metal foil with an easily strippable resin surface protective sheet. SOLUTION: A thermosetting polyphenylene ether resin layer 2 is formed on one surface of an electrolytic copper foil 3 for a printed board by applying a resin varnish composed of a thermosetting polyphenylene ether resin and a toluene solvent and drying the applied varnish film. Then the easily strippable protective sheet of the metallic foil 3 carrying the thermosetting polyphenylene ether resin layer 2 is formed by press contacting a polyethylene film with the surface of the resin layer 2 with a hot roll maintained at 100 deg.C. Therefore, the reliability of the metallic foil 3 can be improved because the surface of the foil 3 is not contaminated with the thermosetting resin at the time of preserving the foil 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a composite sheet used for manufacturing a multilayer wiring board.

[0002]

2. Description of the Related Art In recent years, there has been a remarkable trend toward miniaturization and high-density mounting methods in the field of electronic devices for communication, consumer use, industrial use, and the like, and accordingly, materials have become more excellent. Heat resistance and electrical characteristics in a high frequency range are being demanded. In the electric wiring board industry, it is urgent to establish a laminated build-up method that can form higher-density wiring than the plated through-hole method, but it can be used for high-speed digital circuits and high-frequency analog circuits. There was no metal foil with resin for a multilayer wiring board. For example, as a resin-attached base material and a resin sheet having a thermosetting resin film, there are those using a conventional epoxy resin, but the epoxy resin has poor electric characteristics, particularly in a high-frequency region, and is difficult to handle. In this case, there is a drawback that resin powder easily falls off.

[0003]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and has been described in detail. A multilayer wiring characterized by having an easily peelable resin surface protection sheet that is not easily dropped, does not contaminate the surface of the metal foil with a thermosetting resin during storage, and is extremely easy to handle in practical use It is intended to provide a composite sheet for a board.

[0004]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, they can easily peel off the thermosetting grease surface of the resin-attached metal foil for a multilayer wiring board. By coating with a suitable resin surface protection sheet, the composite sheet for a multilayer wiring board of the present invention was completed. That is, the present invention is a composite sheet for a multilayer wiring board, wherein a thermosetting resin layer is provided on a metal foil, and a protective sheet which can be easily peeled off is provided on the resin surface.

The above-mentioned multilayer wiring board, wherein the thermosetting resin is a thermosetting resin having a relative dielectric constant of 3.3 or less in a frequency region of 1 MHz or more and a resin flow amount of 1% to 50%. Is a preferred embodiment of the present invention. Hereinafter, the present invention will be described in detail. Examples of the metal foil used in the present invention include a copper foil, an aluminum foil, a tin foil, and a gold foil.

[0006] The thickness of the metal foil is 500 in terms of ease of handling.
μm or less, more preferably 200 μm or less,
Most preferably, it is 105 μm or less. The surface of the metal foil on which the thermosetting resin film is formed may be roughened and / or subjected to a coupling treatment in order to enhance the adhesion to the resin. The roughened electrolytic copper foil manufactured and sold for manufacturing a wiring board can be used as it is for manufacturing the metal foil with resin of the present invention.

As the thermosetting resin used in the present invention, for example, thermosetting polyphenylene ether resin, phenol resin, epoxy resin having a low dielectric constant, diallyl phthalate resin, divinylbenzene resin, polyfunctional acryloyl resin, polyfunctional resin Examples include methacryloyl resins, polyfunctional maleimide resins, polyfunctional cyanate ester resins, polyfunctional isocyanate resins, unsaturated polyester resins, polybutadiene resins, and crosslinkable polymers such as styrene-butadiene-styrene-butadiene-styrene. . These resins are not limited to a single compound due to industrial technology,
Various other substances have been added or modified to obtain the desired properties. A thermoplastic resin may be blended with the thermosetting resin.

[0008] Among the above examples of the thermosetting resin, the thermosetting resin used in the resin-coated metal foil of the present invention is preferably a thermosetting polyphenylene ether resin or a thermosetting polyphenylene containing a polystyrene-based polymer. A resin composition containing an ether resin, a resin composition containing polybutadiene, and a polymer and / or copolymer of triallyl cyanurate and / or triallyl isocyanurate.

In the present invention, fillers and additives can be blended and used in the thermosetting resin in an amount that does not impair the original properties for the purpose of imparting desired performance according to the use. The filler may be fibrous or powdery, and may be silica, alumina, talc, mica, glass beads,
Glass hollow spheres and the like can be given. In addition, as additives, flame retardants, antioxidants, heat stabilizers, antistatic agents,
Plasticizers, pigments, dyes, coloring agents, and the like are included.

In order to obtain a multilayer wiring board having higher reliability, a thermosetting resin having a relative dielectric constant of 3.3 or less and a resin-coated metal foil for a multilayer wiring board are required. It is preferable that the resin flow amount is 1% or more and 50% or less. When the relative permittivity of the thermosetting resin is 3.3 or less, preferably 3.0 or less in a frequency region of 1 MHz or more, the resin after thermosetting also has a small relative permittivity. If the relative permittivity of the insulating layer is small, the width of the wiring can be widened, and therefore, even if the wiring is manufactured under the same process, the variation in the characteristic impedance is reduced. Also,
Crosstalk is reduced.

[0011] The resin flow amount of the thermosetting resin is 1% or more 5
If it is 0% or less, it is suitable for manufacturing a multilayer wiring board, and the resin flow rate is more preferably 5% or more and 50% or less, most preferably 7% or more and 45% or less. If the resin flow amount is less than 1%, defective embedding of the internal circuit occurs, and it is difficult to form a multilayer wiring board. A larger amount of resin flow facilitates embedding of the inner layer circuit. However, with a resin flow amount exceeding 50%, the thickness of the insulating layer cannot be kept constant in the wiring board, and the characteristic impedance of the wiring is kept constant. Can not do.

The resin flow amount is measured by the following method. 1) The weight of a metal foil of 10 cm × 10 cm is measured, and this weight is defined as a. 2) The weight of the metal foil with resin of 10 cm × 10 cm is measured, and this weight is defined as b. 3) The above resin-coated metal foil was heated at a temperature of 170 ° C. and a pressure of 2
After pressurizing at 2 kg / cm ² for 10 minutes, the resin protruding from the metal foil is removed, and the weight of the resin-coated metal foil of the remaining resin is measured, and this weight is referred to as b ′.

4) The amount of resin flow is determined by the following equation.

[0014]

(Equation 1)

The thickness of the thermosetting fat film is preferably 10 μm or more after drying from the viewpoint of easy handling.
μm or more is more preferable, and 30 μm or more is most preferable. Examples of the solvent used for producing the varnish include aromatic hydrocarbons such as benzene, toluene, and xylene; halogen solvents such as dichloromethane, chloroform, and trichloroethylene; and THF. it can. As a method of applying a varnish comprising a thermosetting resin and a solvent, an aired coater, a blade coater, a rod coater, a knife coater,
A method using a device such as a gravure coater, a reverse coater, or a cast coater may be used. Hot air drying, roll heating drying, infrared drying,
A method using a device such as far-infrared drying may be mentioned, and in practice, these devices may be used alone or in combination of two or more.

The composite sheet of the present invention becomes a useful material for a multilayer wiring board which is extremely easy to handle practically because the surface of the thermosetting resin film is covered with a protective sheet which can be easily peeled off. The present invention is a composite sheet in which a metal foil, a thermosetting resin film, and a protective sheet that can be easily peeled off from the resin film are adhered in this order. As a manufacturing method, a procedure in which a protective sheet is pressure-bonded to a resin-coated metal foil by heating and pressurizing, and a procedure in which a metal foil is closely attached to a previously formed thermosetting resin film on the protective sheet are used. Both are possible.

As the easily peelable sheet, a resin film is preferable. Among them, polyethylene, polypropylene, polyethylene terephthalate and the like are preferable from the viewpoint of heat resistance. Further, the film surface may be peeled with water glass, silicone resin, or fluorine resin. FIG. 1 shows a schematic view of a composite sheet for a multilayer wiring board of the present invention.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described with reference to examples to further clarify the present invention.

[0019]

EXAMPLE 1 A resin varnish comprising a thermosetting polyphenylene ether resin and a toluene solvent was applied to one side of a 12 μm thick electrolytic copper foil for printed circuit boards so that the resin thickness after drying was 50 μm. In drying the coating film, a hot air drier was used. A 10 μm-thick polyethylene film was pressure-bonded to the resin surface of the obtained metal foil with thermosetting polyphenylene ether resin using a hot roll at 100 ° C. to obtain a protective sheet coated with the resin-coated metal foil. With the protective sheet attached, wrap it around a 10 cm diameter cylinder at 23 ° C
For one week, the surface of the metal foil is not contaminated with the thermosetting polyphenylene ether resin, and the multi-layer wiring board is manufactured by successive lamination during processing such as cutting of the composite sheet or by peeling off the protective sheet. There was no resin powder drop during handling, and a highly reliable multilayer wiring board could be manufactured. When the edge of the pressed polyethylene film was rubbed with a finger, it could be easily peeled off from the end.

[0020]

Comparative Example 1 A resin varnish composed of a thermosetting polyphenylene ether-based fat and a toluene solvent was applied to one side of a 12 μm-thick electrolytic copper foil for printed circuit boards so that the resin thickness after drying was 50 μm. In drying the coating film, a hot air drier was used. When the obtained metal foil with thermosetting polyphenylene ether-based resin was wound around a cylinder having a diameter of 10 cm and stored at 23 ° C. for one week, the surface of the metal foil was contaminated with the thermosetting polyphenylene ether-based resin, Resin powder fall was observed during processing such as cutting of foil or when manufacturing multilayer wiring boards by sequential lamination, and when the cross section of the manufactured multilayer wiring board was observed, resin embedding failure occurred in the circuit part. Was.

[0021]

The composite sheet for a multilayer wiring board of the present invention is characterized as a highly reliable material for a multilayer wiring board, which is free from contamination of the metal foil with resin, does not fall off during processing and handling, and has no characteristic. . Therefore, the composite sheet for a multilayer wiring board of the present invention is suitably used as a resin material for a wiring board that can be used for high-speed digital circuits and high-frequency analog circuits.

[Brief description of the drawings]

FIG. 1 is a schematic view of a composite sheet for a multilayer wiring board of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Protective sheet easily peelable 2 Thermosetting resin layer 3 Metal foil

Claims (2)

[Claims] 1. A composite sheet for a multilayer wiring board, wherein a thermosetting resin layer is provided on a metal foil, and a protective sheet which can be easily peeled off is provided on the resin surface. 2. The thermosetting resin has a relative dielectric constant of 3.3 or less in a frequency region of 1 MHz or more and a resin flow amount of 1%.
The composite sheet for a multilayer wiring board according to claim 1, comprising a thermosetting resin having a content of at least 50%.