JPH0352291A - Manufacture of printed circuit board having semicircular through-hole - Google Patents

Abstract

PURPOSE:To prevent copper plating from peeling by making a plurality of holes for through-holes along the boundary of the discrete substrate region of a main substrate, coating said main substrate except the discrete-substrate- region-side inner walls of the holes with plating resist, and forming copper plating layers on the discrete-substrate-region-side inner walls. CONSTITUTION:When holes 26 for through-holes are made in a printed circuit board 21, plating resist 27 is applied thereto except half of the inner wall of each of the holes 26 and sections where wiring patterns are formed, and copper plating is formed, copper plating layers 28 are formed only on the sections where the plating resist 27 is not applied. The printed circuit board is cut at line A through the centers of the holes 26 to divide the inner walls thereof into inner walls plated with the copper plating layers 28 and unplated inner wall. Slit formation enables accurate cutting and the holes having inner walls plated with the copper plating layers 28 are used as semicircular through-holes 23. Thereby the copper plating 28 can be prevented from peeling in forming the semicircular through-holes.

Description

[Detailed Description of the Invention] [Summary] This invention relates to a method for manufacturing a printed circuit board that has semicircular through holes in place of lead terminals on the end face of the board, and aims to prevent peeling of copper plating when forming semicircular through holes. , a method for manufacturing a printed circuit board having semicircular through holes on the side surface of the board, which includes the steps of: drilling holes for multiple through holes along the boundaries of individual board areas of a parent board from which multiple printed circuit boards are cut; A step of covering with a plating resist leaving the inner periphery of the individual substrate area, a step of forming a copper plating layer on the inner periphery of the individual substrate area of the same size, and forming the boundary line on the parent substrate as one side. The method is configured to include the steps of forming slits to separate the plurality of printed circuit boards and exposing semicircular through holes that are divided into the holes.

[Industrial application field]

The present invention relates to a method of manufacturing a printed circuit board having semicircular through holes in place of lead terminals on the side surface of the board.

Modular components, represented by mixed integrated circuits (HICs), are a system in which multiple electronic components that make up a required circuit are mounted on a small printed circuit board, and the entire circuit component is mounted on another board, such as a motherboard. be done. Mounting (soldering) on the motherboard is generally done using lead terminals, but as shown in Japanese Utility Model Application No. 60-1α1774 and Japanese Utility Model Application No. 61-106066, soldering is done using lead terminals. Another method is to use a circular through hole.

[Prior art] Figure 3 is a perspective view of an HIC with a semicircular through hole.
IO is the motherboard, and 20 is HIC. H.I.C.
20, various chip parts 2 are mounted on a small printed circuit board 21.
2 is surface mounted, and a plurality of semicircular through holes 23 are formed in the side surface of the substrate 21 in place of lead terminals. A land l1 is formed on the surface of the motherboard 100 at a position corresponding to the semicircular through hole 23 of the HIC 20.

When cream solder 30 is applied to this land 11 and heated with the semicircular through hole 23 of the I{IC 20 placed thereon, the solder melts and is sucked up into the semicircular through hole 23, resulting in a moderate amount of heat. Form fillet and land 1
1. Connect the through holes 23.

FIG. 4 is a perspective view of the HIC with lead terminals. The HIC 20 of this example also has a chip component 22 surface-mounted on a printed circuit board 21, but is of the type that is mounted on the motherboard IO using lead terminals 24. In this case, a through hole (pire hole) 12 is formed in the motherboard 10 at a position corresponding to the lead terminal 24, and the lead terminal 24 is inserted into the hole to perform flow soldering.

[Problem to be solved by the invention]

HIC with semicircular through hole 23 has lead terminal 2
Since the component cost and the manufacturing cost for inserting lead terminals in step 4 can be reduced, the total cost of the HIC can be reduced. There is also the advantage that the density can be increased by eliminating the pie holes 12 on the motherboard side.

However, the method of actually forming a semicircular through hole is not well established, and if a method such as cutting a normal through hole in the center is used, the copper plating on the inner circumferential surface may peel off. There is.

The present invention aims to prevent peeling of copper plating when forming semicircular through-holes.

[Means to solve the problem]

FIG. 1 is a diagram showing the principle of the present invention, (1). <2A).
(3A). (4A) is a cross-sectional view, (2B), (3
B). (4B) is (2A). (3A). (
4A) are respective plan views.

(1) shows an ordinary printed circuit board in which an adhesive 25.25 is applied to both surfaces of a glass epoxy substrate 21, for example. A hole 26 for a through hole is formed in this printed circuit board in the step (2), and a plating resist 27 is applied in the step (3) to half of the inner circumference of the hole 26 and a portion other than where the wiring pattern is to be provided. Next, when copper plating is performed in step (4), a copper plating layer is formed only on the portions where the plating resist 27 is not applied.

The semicircular through hole of the present invention is made by cutting the printed circuit board that has gone through the step shown in FIG. It is formed by dividing. This cutting can be performed with high accuracy using a slit-shaped cutter, and the side where the copper plating layer 28 is located becomes the semicircular through hole 23.In addition, in this principle diagram, the wiring pattern (#i plating layer 28) is formed by the full additive method. Although the example in which the wiring pattern is provided has been described, the method of providing the wiring pattern is not limited to this.

〔Example〕

FIG. 2 is a plan view showing an embodiment of the present invention, in which 40 is a main board from which a plurality of printed MPtFi 21, 21, . , 42 are slits for cutting in the lateral direction.

The longitudinal direction of the slit 42 is also the cutting line A of the semicircular through hole 23, and the copper plating layer 28 on the inner periphery of the semicircular through hole 23 is exposed at the same time when the printed circuit board 21 is cut out.

Since the cutting by the slit 42 is performed with a slight deviation from the copper plating layer 28, there is no fear that the copper plating layer 28 will be peeled off.

It is also possible to cut the slit 42 first and then plate the inner periphery of the semicircular through hole exposed on the side of the board with copper, but in this case, the cut out base WI. Since it is necessary to apply a plating resist to the side surfaces of 21, it is disadvantageous in terms of cost.

〔Effect of the invention〕

As described above, according to the present invention, when forming a semicircular through hole in place of a lead terminal on the side surface of a printed circuit board, a good semicircular through hole can be formed without damaging the copper plating on the inner surface of the through hole. It has the advantage of being shaped.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the principle of the present invention, Fig. 2 is a plan view showing an embodiment of the present invention, Fig. 3 is a perspective view of an HIC having semicircular through holes, and Fig. 4 is a diagram of an HIC having lead terminals. FIG. In the figure, 21 is a printed circuit board, 23 is a semicircular through hole,
26 is a hole for a through hole, 27 is a plating resist, 2
8 is a copper plating layer, 40 is a parent board, 42 is a slit, and A is a cutting line. Applicant Fujitsu Ten Ltd.

Claims (1)

[Claims] 1. In the method for manufacturing a printed circuit board having semicircular through holes on the side surface of the board, a parent board (40) from which a plurality of printed circuit boards (21) are cut out.
a step of drilling holes (26) for a plurality of through holes along the boundary line of the individual board area; a step of covering the hole with a plating resist (27) leaving the inner periphery on the individual board area side of the hole; a step of forming a copper plating layer (28) on the inner periphery of the individual board area side; and a slit (42) having one side of the boundary line in the parent board.
A method of manufacturing a printed circuit board having a semicircular through hole, comprising the steps of: forming a plurality of printed circuit boards to separate a plurality of printed circuit boards, and exposing a semicircular through hole (23) that is divided by the hole.