JPH0213835B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for manufacturing a high-density wiring board using insulated wires for necessary wiring patterns.

(Prior art) For general printed wiring boards, there is a subtract method in which a wiring pattern is formed by using a copper-clad laminate and dissolving and removing unnecessary parts with chemicals, or a non-copper-clad laminate is used to form a wiring pattern in the necessary parts. Manufactured by an additive method that deposits electroless plating.

In both of these methods, uninsulated wiring is formed on a plane, so it is not possible to cross the wiring on the same plane.For crossing wiring, different planes are used and through holes are formed between the plane layers by electroless plating, etc. It is metallized to make interlayer connections. As a high-density wiring board that does not have these drawbacks and is suitable for high-mix, low-volume production, it 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 the insulated wires are held in the adhesive layer for wiring. Hitachi Chemical Co., Ltd. (product name)) has been proposed. For multi-wire wiring boards, a thermosetting adhesive that retains thermoplasticity is laminated or coated on an insulating substrate such as a thermosetting resin laminate when wiring (wires are placed in the adhesive and bonded at the same time). Then wire an insulated wire using a numerically controlled wiring machine, fix the wiring pattern using a press, etc., make a through hole across the wire at a predetermined position, expose the cut end of the wire on the peripheral wall of the through hole, It is manufactured by forming an electroless metal layer on the inner wall of the through hole to connect with the cut end of the wire. Since the multi-wire wiring board uses insulated wires, the wiring can be crossed or arranged in close parallel, making it suitable for high-density wiring.

However, even in this multi-wire wiring board, when three or more wires are connected between through holes with a pitch of 2.54 mm, the pitch of the insulated wires is 0.3 mm.
As a result, crosstalk noise between adjacent parallel insulated wires becomes a problem.

Therefore, for circuits using high-speed signals, it was common to run two insulated wires between 2.54 mm pitch through holes. Since such a circuit board is usually required to be miniaturized, the wiring capacity is insufficient, the number of required wiring layers increases, and the cost becomes high.

(Problem to be solved by the invention) Conventional wiring is performed only in parallel and perpendicular directions (referred to as X and Y directions) to an insulating substrate, and the wiring layer in the X direction and the wiring layer in the Y direction are separated into , the number of layers is increased if necessary, and the layers are connected using through holes. Therefore, the overall thickness has increased.

In addition, since multi-wire wiring boards can intersect on the same plane, it is possible to conduct wiring in both the I was not aware of it. The reason for this is that during normal wiring, vibration is applied by the wiring machine to fix the insulated wire to the adhesive, and when fixing the wire in the X and Y directions, the upper The insulated wires are not fixed with adhesive and are routed over the lower insulated wires, so the adhesive strength of the upper insulated wires is weak at the points where they intersect. Another reason is that the second insulated wire may be moved by the vibration of the wiring machine, or may be caught by the head of the wiring machine and broken.

However, since the diagonal wiring is in principle the shortest wiring and is not parallel to the X and Y directions, the crosstalk noise is also small.

Therefore, if it becomes possible to wire the X- and Y-direction wires and the diagonal wires within the same plane, it can be said to be most suitable for high-speed circuitry and high-density packaging.

In order to enable wire wiring, it is necessary that the wiring can be crossed three times or more, and that the diagonal wiring does not come into contact with the through holes on the 2.54 mm grid.

The present invention has been made in view of these points, and provides a method for manufacturing a wiring board that is low in cost and has high density, particularly in the thickness direction, by wiring with little crosstalk noise.

(Means for Solving the Problems) The method of manufacturing a high-density wiring board using insulated wires in the necessary wiring pattern of the present invention is to apply an adhesive to an insulated substrate, and then place the insulated wires on the adhesive. At the same time, it is bonded to form a wiring pattern.
In the manufacturing method of high-density wiring boards using insulated wires for the necessary wiring pattern, which consists of drilling through holes across the insulated wires and metallizing the insides of the through holes, the process of placing the insulated wires on the insulated substrate is It is characterized by being divided into a process of wiring mainly in the right angle direction and a process of wiring mainly in the 45-degree direction on the board, and a process of embedding the previously performed wiring in adhesive as an intermediate process.

That is, in the present invention, the process of putting insulated wires on the adhesive (wiring process) is divided into two processes, wiring in the XY direction and diagonal wiring are separate processes, and in addition, between these processes, By embedding the wires in the adhesive, the insulated wires that crossed during the previous wiring can be firmly fixed, preventing movement of the insulated wires, and reducing the height to be crossed when wiring diagonally. This is to prevent wire breakage.

Furthermore, in order for the diagonal wiring to be able to be freely routed while avoiding contact with the through-holes, since the through-holes are on a regular grid, this can be achieved by passing through the midpoints of the grid and making the wiring at a 45 degree angle. This 45
It is not necessarily possible to complete the wiring using only parallel wiring, and it is necessary to use a portion of the wiring in the X or Y direction, but since this portion is short, the crosstalk noise is small.

Fig. 1 is a partially cutaway plan view of a multi-wire wiring board having wiring only in the XY directions, 1 is a through hole, 2 is an insulated wire wired in the XY directions, and Fig. 2 is a multi-wire wiring board according to the present invention. 3 is a partially cutaway plan view of a wiring board, 3 is an insulated wire wired diagonally, FIG. 3 is a perspective view of a multi-wire wiring board according to the present invention, and 4 is a base (inner layer).
The substrate, 5, is an adhesive.

Example 1 Copper-clad glass-epoxy laminated board (Hitachi Chemical Co., Ltd.)
Co., Ltd. (product name: MCL-E-168) 1.6 mm thick was etched using the usual method to create a base board with one side as a power layer and the other side as a ground layer.

A multi-wire adhesive prepreg HA-05G (trade name, Hitachi Chemical Co., Ltd.) was laminated and adhered to this base substrate using a hot press at a heating temperature of 150°C, a pressure of 20 kg/cm ² , and a heating and pressing time of 10 minutes.

Next, the wire diameter is 0.14mm using a multi-wire wiring machine.
Insulated wires with the minimum pitch mainly in the Z and Y directions
Wired with 0.508mm.

This board was removed from the wiring machine and heat pressed again under the above conditions to embed the wiring in the adhesive. This board is further coated with a wiring machine.
The wiring was mainly 45 degree diagonal wiring. The resulting wiring included wiring in the XY direction and at a 45 degree diagonal, achieving high-density wiring without causing wire movement or disconnection.

Example 2 Copper-clad glass-epoxy laminate MCL-E-161
(Product name of Hitachi Chemical Co., Ltd.) A base board with a thickness of 1.6 mm was etched using the usual method to create a base board with one side as a power layer and the other side as a ground layer. On this base substrate, multi-wire adhesive Prepreg HA-05G (trade name, Hitachi Chemical Co., Ltd.), 0.25 mm thick, was laminated and bonded on both sides by hot pressing.

Next, insulated wires with a wire diameter of 0.10 mm were wired mainly in the XY direction with a minimum pitch of 0.406 mm using a multi-wire wiring machine. Remove this board from the wiring machine and
The wire was embedded in the adhesive at a speed of 1 m/min using a roll heated to °C.

This board was further wired using a wiring machine, mainly 45-degree diagonal wiring, and the post process was a multi-wire wiring board using the usual process.

(Effects of the Invention) As described above, the present invention has been able to provide a method for manufacturing a high-density wiring board using insulated wires for the necessary wiring pattern, which can achieve the following effects.

(1) By separating the process of wiring the wiring in the X and Y directions and the wiring in the diagonal direction, and adding a process of embedding the wires in adhesive in the intermediate process, the wiring in the four directions can be formed on the same plane. , could prevent wire movement and disconnection.

(2) Wiring can be done in four directions within the same plane, allowing for high-density wiring in the thickness direction.

In addition to the above effects, (3) Crosstalk noise can be reduced compared to a wiring board with the same amount of wiring only in the X and Y directions.

(4) By limiting the diagonal direction to 45 degrees, wiring that comes into contact with through-holes can be avoided, increasing the degree of freedom in wiring design.

It was possible to have this effect.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway plan view of a multi-wire wiring board showing a conventional example, Fig. 2 is a partially cutaway plan view of a multi-wire wiring board showing an embodiment of the present invention, and Fig. 3 is an embodiment of the present invention. FIG. 2 is a partially cutaway perspective view of a multi-wire wiring board. Explanation of symbols: 1... Through hole, 2... Insulated wire wired in the X and Y directions, 3... Insulated wire wired in diagonal direction, 4... Base (inner layer) substrate, 5... Adhesive.

Claims (1)

[Claims] 1. Apply adhesive to an insulated substrate, place insulated wires on the adhesive and adhere at the same time to form a wiring pattern, make a through hole across the insulated wire, and metalize the inside of the through hole. In the manufacturing method of high-density wiring boards using insulated wires for the necessary wiring patterns, there are two steps: one is to wire the insulated wires mainly at right angles to the insulated substrate, and the other is to route the wires mainly at right angles to the insulated substrate. A method for manufacturing a high-density wiring board using wire for a necessary wiring pattern, which is divided into a main process of wiring, and has a process of embedding previously performed wiring in adhesive as an intermediate process.