JPH06120641A - Insulated wire and wiring board employed for wiring pattern requiring insulated wire - Google Patents

Abstract

PURPOSE:To obtain a thin wire for suppressing disconnection at intersections by employing a specific insulated wire. CONSTITUTION:An adhesive layer is formed on an insulating board and an insulated wire, comprising an insulating layer and a copper core wire, is laid on the adhesive to form a wiring pattern. The insulating board is then thermally pressed and embedded in the adhesive. Through holes are then made traversing the insulated wire and the inside of the through hole is metallized thus producing a wiring board. In the insulated wire being employed for such wiring board, the thickness of insulation layer is set at 18-30mum and a copper wire having diameter of 77-83mum is employed as the core wire.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulated wire and a wiring board using the insulated wire for a required wiring pattern.

[0002]

2. Description of the Related Art As a general printed wiring board, a subtraction method is mainly used in which a copper-clad laminate is used to dissolve and remove unnecessary portions with a chemical to form a wiring pattern. On the contrary, an additive method in which electroless plating is deposited on a necessary portion using a laminated plate without attaching copper is becoming popular. In all of these, since wiring is formed on a plane, cross wiring cannot be performed on the same plane. For cross wiring, different planes are used, through holes are provided between the plane layers, and the through holes are plated. And metallization is performed for interlayer connection.
As a high-density wiring board that has improved such drawbacks, there is a wiring board (hereinafter referred to as a multi-wire wiring board) in which an adhesive layer is provided on an insulating substrate and an insulated wire is held by the adhesive layer for wiring.

A multi-wire wiring board is one in which a thermosetting adhesive is laminated or applied on an insulating substrate and an insulated electric wire is laid by a numerical control wiring machine to remove air bubbles generated in the vicinity of the insulated electric wire. Moreover, in order to embed and fix the insulated wire in the adhesive, the insulated substrate after wiring is heated and pressed. Then, a thermosetting resin is press-bonded and fixed onto an insulated electric wire (hereinafter referred to as a wire) by a press or the like, a hole is formed across the wire, and a metal layer is formed in the hole by plating. Since the multi-wire wiring board uses wires, the wiring intersects, and even if parallel wiring is close, the insulation is high and suitable for high-density wiring.

The multi-wire wiring board has a core wire diameter of 100 μm.
m, the insulating layer film thickness is 15 μm, and the elongation is 45% or more and 70% or less.

[0005]

However, in order to cope with the high density of the wiring, the current core wire diameter is 100 μm, the thickness of the insulating layer is 15 μm, and the elongation is 45% to 70%.
Many disconnections occur at intersections. In addition, as the density of wiring has been increased, there has been a demand for finer wires. The present invention provides a thin wire with less disconnection at the intersection.

[0006]

In the insulated wire of the present invention, an adhesive layer is applied and formed on an insulating substrate, and the insulated wire composed of the insulating layer and a copper core wire is put on the adhesive and simultaneously bonded. After forming the wiring pattern, heat and pressurize this insulating substrate to embed and fix it in the adhesive layer, open a through hole that crosses the insulated wire, and metallize the inside of the through hole. In the electric wire, the film thickness of the insulating layer is set to 18 μm to 30 μm.
In addition, such an insulated wire has a core wire diameter of 77 μm.
Copper wires of ˜83 μm can be used.

[0007]

Example 1 Tough pitch copper (trade name, manufactured by Hitachi Cable, Ltd.) is used as a core wire, and after annealing at 350 ° C. or higher and 450 ° C. or lower, it is an insulating coating mainly composed of polyimide as an insulating layer. Pyr-ML-RC-5057 (manufactured by DuPont,
(Brand name), baking temperature 300 ℃ -450 ℃, number of passes 3
Baking is performed 0 to 50 times. After that, HAW-216D (manufactured by Hitachi Chemical Co., Ltd., trade name) which is an adhesive resin as an adhesive layer was overcoated at 150 ° C. or higher and 300 ° C. or lower to manufacture the wires shown in Table 1. However, if the thickness of the insulating layer exceeds 30 μm, the outer diameter of the wire becomes large, and it was judged that the wire was not suitable for high-density wiring. Table 1 shows the results of investigation of the number of disconnection points using a wiring pattern including 117 quadruple intersections that are difficult to perform wiring.
As is apparent from this, the insulating layer film thickness is 18 μm to 30 μm.
By using the wire of m, it is possible to suppress the disconnection at the intersection, which is a problem in high-density wiring.

[0008]

[Table 1] The diameter of the core wire is 77 μm to 83 μm

[0009]

As described above, in the manufacture of a multi-wire wiring board, by using a wire having a core wire diameter of 77 μm to 83 μm and an insulating layer film thickness of 18 μm to 30 μm, it is possible to suppress disconnection at the intersection.

Claims (3)

[Claims] 1. An adhesive layer is formed on an insulating substrate by coating, and an insulating electric wire composed of an insulating layer and a copper core wire is placed on the adhesive and simultaneously bonded to form a wiring pattern. In an insulated wire used for a wiring board, which is formed by heating and pressurizing, embedding and fixing it in an adhesive layer, opening a through hole across the insulated wire, and metallizing the inside of the through hole, the thickness of the insulating layer is 18 μm to An insulated wire characterized by having a thickness of 30 μm. 2. The diameter of the copper core wire of the insulated wire is 77 μm.
The insulated electric wire according to claim 1, wherein the insulated electric wire has a thickness of about 83 μm. 3. A wiring board using the insulated wire according to claim 1 or 2.