JPS63265494A - Multilayer interconnection board - Google Patents

Abstract

PURPOSE:To form a high-density multilayer flexible printed interconnection board which has a high flexibility and is easy to be produced continuously by a method wherein the upper surface and the lower surface of an inner layer material composed of a thermoplastic resin layer and circuits formed on its surfaces are coated with metal foils with resin layers between and the whole layers are unified. CONSTITUTION:Metal foils 4 are applied to the upper surface and/or the lower surface of an inner layer material composed of a thermoplastic flexible resin layer 1 and circuits 2 formed on its surfaces with resin layers 4 between and the whole layers are unified. As the flexible and bendable thermoplastic resin layer is employed as the inner layer material, the board can be applied easily to a complex shape and a complex structure such as an L-type wiring and, moreover, by providing a multilayer interconnection, a high density interconnection can be achieved. Moreover, the board can be continuously formed as the multilayer interconnection board and, by processing the outer surface metal layers by a method such as etching, flexible printed interconnection circuits can be easily formed by common processing manufacturers.

Description

[Detailed description of the invention] (Technical field) The present invention relates to a multilayer wiring board.

More specifically, the present invention relates to a multilayer wiring board that is capable of visible three-dimensional wiring such as L-shaped wiring.

(Background Art) Printed wiring boards have been widely used in electrical and electronic equipment, communication equipment, computing equipment, and the like. These printed wiring boards are used to reduce the size and thickness of electronic equipment, communication equipment, etc.
In order to cope with the increasing complexity, flexible printed wiring boards using visible resin for printed wiring board substrates and multilayer wiring boards that enable high-density wiring have been developed.
It is being put into practical use.

However, with regard to conventional flexible printed wiring boards, the flexibility of the board itself is not very great, and the current situation is that the wiring density has not been increased by increasing the number of layers. Moreover, the manufacture of conventional flexible printed wiring boards has been limited to special processing manufacturers.

For this reason, ultra-thin and compact cards, etc.

High-density flexible printed wiring boards that can be used in electrical and electronic devices, which are becoming increasingly complex, have not yet been realized.

(Objective of the Invention) This invention was made in view of the above circumstances, and provides a high-density multilayer flexible print that has great flexibility and is easy to continuously produce, which has not been realized to date. The purpose is to provide wiring boards.

(Disclosure of the Invention) In order to achieve the above object, the multilayer wiring board of the present invention has metal foil arranged on the upper and/or lower surface of the inner layer material with a circuit formed on the surface of the thermoplastic resin layer via a resin layer. It is characterized by being integrated.

The multilayer wiring board of the present invention will be explained along with the attached drawings.

FIG. 1 shows an example of the multilayer wiring board of the present invention. In this example, a metal foil 4 is integrally provided on the upper and lower surfaces of an inner layer material with a circuit 2 formed on the surface of a thermoplastic flexible resin layer 1 via a resin layer 3. metal foil 4
FIG. 2 shows a case where a circuit is formed by etching and used as an L-shaped wiring board.

The resin for the thermoplastic resin layer 1 of this multilayer wiring board is preferably a resin with a high heat resistance such as polyamide, polyimide, polyester, or fluorinated resin, and JIS-K
・Continuous heat resistance temperature 71.8℃ corresponding to 7201 standard
The above are preferably used.

This thermoplastic resin can be used as a sheet or plate-shaped body. In addition, layer 1 made of this thermoplastic resin
may be a resin-impregnated base material layer.

In this case, impregnation involves applying a resin face dissolved or dispersed in a solvent to paper, woven fabric (glass cloth, synthetic fiber cloth, etc.),
This can be carried out by impregnating a base material such as a nonwoven fabric or mat, and drying it if necessary.

Alternatively, a thermoplastic resin sheet or film may be laminated onto these base materials, and the thermoplastic resin may be melted and impregnated during the base material sewing.

A 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 metal or alloy such as copper, aluminum, nickel, zinc, iron, stainless steel, etc. is formed on the surface of this resin layer 1. It may also be used alone.

When forming the circuit 2, the metal or alloy foil as described above is integrated with the thermoplastic resin layer 1 by applying an adhesive if necessary, and then the circuit can be formed by etching or the like. The thickness of the circuit is preferably 0.
The tan should be approximately 0.018 to 0.07.

A resin layer 3 and a metal foil 4 are further disposed on the circuit 2, and the resin layer 3 is made of the above-mentioned thermoplastic resin,
Alternatively, thermosetting resins such as epoxy resins, phenolic resins, unsaturated polyester resins, thermosetting polyimide resins, etc. are coated as liquid materials, paper, woven cloth, glass cloth, etc.
It can be a resin-impregnated base layer formed by impregnating synthetic fiber cloth, etc.), nonwoven fabric, mat, etc., a resin sheet layer, a resin film layer, or a FMWI layer in combination with these.

As with the circuit 2 described above, the metal foil can preferably be disposed to a thickness of about 0.05 to 0.07 wm. This metal foil can also be used to form two circuits (as illustrated in FIG. 12) by etching or the like.

Since a flexible and bendable thermoplastic resin layer is used as the inner layer material, it is easy to handle complex shapes and structures such as L-shaped open wires, and since it is a multilayer wiring board, the wiring height can be reduced. Densification is also achieved.

Furthermore, it can be continuously molded into a multilayer wiring board, and even general processing manufacturers can easily form circuits on flexible printed wiring boards by etching the metal foil on the outer surface.

Next, the multilayer wiring board of the present invention will be described in more detail by showing examples.

Example 1 Copper foils with a thickness of 0.018 am were adhered to the upper and lower surfaces of a polyester film with a thickness of 0.5 mm, and then etched to form a circuit.

Two sheets of epoxy resin-impregnated glass cloth with a thickness of 0.81 mm are stacked on each of the upper and lower surfaces of the inner layer material made of polyester film on which a surface circuit has been formed, and copper foil with a thickness of 0.018+m+ is placed on top of each layer. The arranged laminate was pressure molded at a molding pressure of 401 qr/cd and a temperature of 160° C. for 20 minutes to produce a multilayer wiring board.

The flexibility of this multilayer wiring board was good.

Example 2 Two layers of polyester-impregnated nonwoven fabric, which is a nonwoven fabric with a thickness of 0.2 mm and impregnated with polyester resin, are stacked on top and bottom surfaces with a thickness of 0.2 mm. ◇2ffiu+ copper foil was bonded and then etched to form a circuit. Two sheets of epoxy resin-impregnated glass cloth with a thickness of 0.1 nua are stacked on each of the upper and lower surfaces of this inner layer material, and on top of that, epoxy resin-impregnated glass cloth with a thickness of 0.01
A copper foil of 500 m was placed on the plate, and lamination molding was carried out for 20 minutes at a molding pressure of 40 kir/aJ and a temperature of 160°C.

A multilayer wiring board with excellent flexibility was obtained.

(Effects of the Invention) The multilayer wiring board of the present invention realizes a high-density flexible printed wiring board that can be used in electrical and electronic equipment, etc., which are becoming smaller, thinner, and more complex.

Moreover, the multilayer wiring board of the present invention can be easily processed by continuous molding, etching, etc., and has excellent productivity.

[Brief explanation 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 L-shaped wiring. DESCRIPTION OF SYMBOLS 1...Thermoplastic amorous layer, 2...Circuit, 3...Resin layer 4...Metal foil.

Claims (2)

[Claims] (1) A multilayer wiring board characterized in that a metal foil is integrally arranged on the upper and/or lower surfaces of an inner layer material with a circuit formed on the surface of a thermoplastic resin layer via a resin layer. (2) The multilayer wiring board according to claim (1), wherein the thermoplastic resin layer is a resin-impregnated base material layer.