JPH07120854B2 - Multilayer wiring board - Google Patents

Description

TECHNICAL FIELD The present invention relates to a multilayer wiring board. More specifically, the present invention relates to a flexible multi-layer wiring board capable of three-dimensional wiring such as L-shaped wiring.

(Background Art) Printed wiring boards have been widely used in electric / electronic devices, communication devices, computing devices, and the like. For these printed wiring boards, downsizing and thinning of electronic devices, communication devices, etc.
Or in order to cope with the complexity, a flexible printed wiring board using a flexible resin for the substrate of the printed wiring board and a multilayer wiring board that enables high-density wiring have been developed.
It has been put to practical use.

However, in the conventional flexible printed wiring board, the flexibility of the substrate itself is not so great, and the density of the wiring is not advanced due to the multilayer structure. Moreover, until now, the production of flexible printed wiring boards was limited to special processing manufacturers.

For this reason, a high-density flexible printed wiring board that can be used in electric / electronic devices and the like, which have become ultra-thin and compact such as cards, and are becoming more complicated, has not yet been realized.

(Object of the Invention) The present invention has been made in view of the above circumstances, and has not been realized so far, has high flexibility, and has a high-density multilayer flexible print that is easy to continuously manufacture. It is intended to provide a wiring board.

DISCLOSURE OF THE INVENTION In order to achieve the above object, the multilayer wiring board of the present invention has a continuous heat resistance temperature of 77.8 which corresponds to the standard of JIS K7201.
A metal foil is disposed and integrated through the resin layer on either or both of the upper surface and the lower surface of the inner layer material having a circuit formed on the surface of the thermoplastic resin layer formed of a thermoplastic polyester resin having a temperature of ℃ or higher. Is characterized by.

The multilayer wiring board of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows an example of the multilayer wiring board of the present invention. In this example, a metal foil is formed on the upper and lower surfaces of an inner layer material in which a circuit 2 is formed on the surface of a thermoplastic resin layer 1 formed of a thermoplastic polyester resin having a continuous heat resistance drop of 77.8 ° C. or more, with a resin layer 3 interposed therebetween. 4 are integrated. FIG. 2 shows a case where the metal foil 4 is etched to form a circuit and is used as an L-type wiring board.

The range of continuous heat resistant temperature of the thermoplastic polyester resin used for the thermoplastic resin layer 1 corresponds to the standard of JIS K7201. This resin layer 1 is used as a sheet or a plate-like body. Alternatively, it may be a resin-impregnated base material layer.

In this case, the impregnation is performed by impregnating a solvent, a thermoplastic resin varnish dissolved or dispersed in the solvent into a substrate such as paper, woven cloth (glass cloth, synthetic fiber cloth, etc.), non-woven cloth, mat, etc., and drying if necessary. This can be done by Alternatively, a sheet or film of a thermoplastic polyester resin may be laminated on those base materials, and the thermoplastic polyester resin may be melt-impregnated between the base fibers.

The required number of thermoplastic resin layers can be stacked and used. For example, in the case of FIGS. 1 and 2, three sheets are used. A circuit 2 made of a metal or alloy such as copper, aluminum, nickel, zinc, iron, and stainless is formed on the surface of the resin layer 1. The circuit 2 is formed on the upper surface and the lower surface of the resin layer 1, or on one of the surfaces. May be only.

When the circuit 2 is formed, the metal or alloy foil as described above may be coated with an adhesive as needed to be disposed and integrated on the thermoplastic resin layer 1, and then the circuit may be formed by etching or the like. The thickness of the circuit is preferably 0.01
It is about 8 to 0.07 mm.

A resin layer 3 and a metal foil 4 are further arranged on the circuit 2, and the resin layer 3 includes the above-mentioned thermoplastic polyester resin, epoxy resin, phenol resin,
Resin impregnated by impregnating unsaturated polyester resin, thermosetting polyimide resin or other thermosetting resin as a liquid material, paper, woven cloth (glass cloth, synthetic fiber cloth, etc.), non-woven fabric, mat, etc. It may be a base material layer, a resin sheet layer, a resin film layer, or a resin layer combining these.

Regarding the metal foil, as in the case of the above-mentioned circuit 2, preferably,
It can be arranged in a thickness of about 0.018 to 0.07 mm. With respect to this metal foil as well, a circuit can be formed by etching or the like as illustrated in FIG.

Since a flexible and flexible thermoplastic polyester resin layer is used as the inner layer material, it is easy to deal with complicated shapes and structures such as L-shaped wiring, and since it is a multilayer wiring board, high wiring Higher density is also realized. Further, it is possible to continuously form a multilayer wiring board, and even a general processing maker can easily form a circuit of a flexible printed wiring board by etching the metal foil on the outer surface.

Next, the multilayer wiring board of the present invention will be described in more detail with reference to examples.

Example 1 On the upper and lower surfaces of a 0.5 mm-thick polyester film,
A 0.018 mm copper foil was adhered and then etched to form a circuit.

Two 0.1mm-thick epoxy resin-impregnated glass cloths are placed on each of the upper and lower surfaces of the inner layer made of polyester film on which the surface circuit is formed, and the thickness is further applied
Forming a laminate with 0.018 mm copper foil molding pressure 40 kg / cm ² ,
A multilayer wiring board was manufactured by pressure molding at a temperature of 160 ° C. for 20 minutes.

The flexibility of this multilayer wiring board was good.

Example 2 Two polyester-impregnated non-woven fabrics in which a 0.2-mm-thick non-woven fabric is impregnated with a polyester resin are stacked, and the upper and lower surfaces thereof have thickness
A 0.02 mm copper foil was adhered and then etched to form a circuit. Two 0.1-mm thick epoxy resin-impregnated glass cloths are placed on each of the upper and lower surfaces of this inner layer material, and a 0.018-mm-thick copper foil is placed on the glass cloth, and the molding pressure is 40 kg. It was pressure-laminated at a temperature of 160 ° C./cm ^{2 for} 20 minutes.

A multilayer wiring board having excellent flexibility was obtained.

(Effect of the Invention) The multilayer wiring board of the present invention realizes a high-density flexible printed wiring board that can be used in electric / electronic devices and the like that are becoming smaller, thinner, and more complicated.

Moreover, the multilayer wiring board of the present invention is easy to process by continuous molding, etching, etc., and is excellent in productivity.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of the present invention, and FIG. 2 is a sectional view showing an example used for an L-type wiring. 1 ... Thermoplastic resin layer, 2 ... Circuit, 3 ... Resin layer 4 ... Metal foil.

Claims (2)

[Claims] [Claim 1] Either the upper surface or the lower surface of an inner layer material having a circuit formed on the surface of a thermoplastic resin layer formed of a thermoplastic polyester resin having a continuous heat-resistant temperature of 77.8 ° C or higher, which corresponds to the JIS / K7201 standard. A multilayer wiring board, characterized in that a metal foil is disposed and integrated on one or both sides through a resin layer. 2. The thermoplastic resin layer is a resin-impregnated base material layer impregnated with a thermoplastic polyester resin having a continuous heat-resistant temperature of 77.8 ° C. or higher which corresponds to the JIS / K7201 standard. The multilayer wiring board according to the item.