JPH05327156A - Printed-circuit board - Google Patents

Abstract

PURPOSE:To manufacture a printed-circuit substrate having outer terminals wherein the plating layers in through holes as the outer terminals are hardly released while the connection bonding onto a mother board is also hardly discon nected. CONSTITUTION:This printed-circuit board is provided with the outer terminals comprising the residual parts of through holes describing over semicircles having plating layers 3 on the wall surface thereof connected to conductor circuits 2 arranged on the surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed circuit board used for mounting electronic parts such as semiconductor chips and electric parts.

[0002]

2. Description of the Related Art Conventionally, a printed circuit board having an external terminal in which a semicircle of a through hole remains on an end surface of the printed circuit board is known as a plastic leadless chip carrier (PLCC). As one of the methods for forming the external terminals on the side surface of the printed circuit board from such a printed circuit board, a through-hole plating layer having a plating layer on the wall surface that is in conduction with the circuit formed simultaneously with the circuit formation of the printed circuit board is formed. Japanese Patent Laid-Open No. 59-158588 discloses a technique in which the center of the through hole is punched and cut while controlling the thickness according to the thickness, but plating on the wall surface of the through hole corresponding to the thickness of the printed circuit board is disclosed. There was a problem that it was difficult to control the thickness. Further, as another method, a method of filling the through holes with solder and cutting the center with a router or dicing is generally used. However, this method has a problem that the cost is high and the process is complicated. Further, in any case, the remaining plating layer on the wall surface of the through hole is easily peeled off, and after the solder board is connected to the wiring circuit of the mother board by soldering, the solder connection part is easily detached by external force such as impact. It also had a problem that was inferior to.

[0003]

SUMMARY OF THE INVENTION Therefore, the present invention provides a printed circuit board having an external terminal in which a plated layer of a through hole as an external terminal is less likely to be peeled off and the connection and fixation to a mother board are not easily removed. Is.

[0004]

Therefore, the present invention has been made in order to solve the above-mentioned problems, and is characterized by the remaining portion of the through hole which exceeds the semicircle of the through hole on the end face of the printed circuit board. In a printed circuit board having external terminals consisting of.

[0005]

[Function] Since the external terminal formed on the end face of the printed circuit board is formed by the remaining portion of the through hole that exceeds the semicircle of the through hole, the remaining plating layer is the greater of the through hole plating layer, and therefore the adhesive strength Becomes more difficult to peel off. Due to such a structure of the end face external terminal, it can be cut reasonably by die punching. In addition, when the end face through hole is viewed from the front, the end face through hole has a shape that widens inside the printed circuit board from the frontage. Even if external force such as impact is applied, the solder connection portion is hard to be physically detached because the solder enters the through hole portion which is spread inside and is fixedly connected to the mother board. As a result, the connection reliability is improved.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings of the embodiments. The present invention is not limited to these examples.

FIG. 1 is a perspective view of a part of a printed circuit board according to an embodiment of the present invention. The printed circuit board is formed by connecting a conductor circuit 2 provided on the surface of an insulating substrate 1 and the conductor circuit 2 to each other. The through hole 4 having the formed plating layer 3 on the wall surface is used as the external terminal 5. The through hole 4 has the end surface processed by the solid line 7 shown in the plan view of the through hole before the end surface processing of FIG. .. The dotted line 6 shown in the plan view of the through hole before the end surface processing in FIG. 2 is a processing line when the end surface is processed by leaving a semicircle in the through hole 4 formed by connecting to the conductor circuit 2, and the solid line 7 indicates the through hole 4. A solid line 7 is a processing line when the end surface is processed so that the portion exceeding the semicircle remains on the insulating substrate 1. The solid line 7 is set on the end surface side by a proportion of 25% or more and less than 100% of the radius of the through hole from the dotted line 6. Is preferred. For example, in the case of a through hole having a nickel plating layer of φ0.35 mm and a thickness of 5 μm on a glass cloth base material epoxy resin printed wiring board having a thickness of 0.6 mm, 0.05 to 0.
Solid line 7 located about 1 mm from the center of the through hole to the end face side
Processed. Therefore, the shape of the external terminal 5 is a notched through hole having an inside wider than the frontage.

The printed circuit board is a printed circuit board having a conductor circuit 2 formed on a copper foil-clad laminate by a subtractive method or a printed circuit board having a conductor circuit 2 formed on the laminate by an additive method, or a conductor circuit 2. A printed circuit board or the like in which metals are bonded together by adhesion can be used. As the resin of the insulating substrate 1 which constitutes these laminated plates, those having excellent heat resistance and moisture resistance and having resin purity, particularly low ionic impurities are preferable. Specifically, a resin such as an epoxy resin, a polyimide resin, a fluororesin, a PPO resin, an unsaturated polyester resin, or a phenol resin is used alone,
It is possible to use those modified, mixed and combined. In addition, these resins include inorganic fillers represented by silica and perfluoroethylene powder, polyethylene powder,
A material containing an organic filler such as polyamide powder can be used. As the base material of the insulating substrate, a glass cloth made of glass fibers, an inorganic base material such as a glass non-woven fabric, or a base material such as an organic fiber having an aromatic polyamideimide skeleton having excellent heat resistance and a combination thereof are used. Can be used.

The through-hole plating layer 3 may be formed of a metal such as solder, copper, nickel, silver or gold, or a combination thereof. When nickel plating is applied on top of copper plating, the thickness of nickel plating is 10 μm
The following is preferable. In addition, electroless plating, electrolytic plating, or the like can be appropriately used as the forming method.

In order to form the external terminals 5 on the side surface of the printed circuit board by cutting the through holes 4 into notches,
A method of punching and cutting with a die a through hole having a plating layer that conducts with a conductive circuit formed at the same time as the circuit formation of the printed circuit board, a method of filling the through hole with solder and then cutting this through hole with a router or dicing, etc. In the printed circuit board structure of the present invention, the external terminal 5 is formed by the remaining portion of the through hole 4 that exceeds the semicircle of the through hole 4, so that the printed circuit board in the through hole plating layer 3 can be used as appropriate. Since there are more plating layers left on the substrate, the adhesive strength increases and it is difficult to peel off, so die punching is preferable for rational production.

[0011]

According to the present invention, it is possible to obtain a printed circuit board having an external terminal in which a plated layer of a through hole as an external terminal is less likely to be peeled off and a connection and fixation with a mother board is not easily removed, and high connection reliability is obtained. It is possible to secure the sex.

[Brief description of drawings]

FIG. 1 is a perspective view showing a printed circuit board according to an embodiment of the present invention.

FIG. 2 is a plan view showing an unprocessed printed circuit board according to an embodiment of the present invention.

[Explanation of symbols]

 1 Insulation board 2 Conductor circuit 3 Plating layer 4 Through hole 5 External terminal

Claims (2)

[Claims] 1. A printed circuit board having an external terminal formed on the end surface of the printed circuit board, the external terminal being formed of a remaining portion of a through hole that exceeds a semicircle of the through hole. 2. The printed circuit board according to claim 1, wherein the remaining portion of the through hole according to claim 1 is formed by die punching.