JPS6312399B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printed wiring board and a method for manufacturing the same, and more particularly, the present invention relates to a printed wiring board and a method for manufacturing the same, and more particularly, a part of the side surface that allows high wiring density and allows visual confirmation of solder buildup. The present invention relates to a printed wiring board having an open bent through-hole, and a method for manufacturing the same, which has features such as extremely little peeling of plating when cutting the through-hole.

Conventionally, as a board having a conductive layer on the side surface of a printed wiring board, for example,
Or, as shown in Figure 1, there is a conductive layer with an opening cut vertically from approximately the center of the through hole, and as shown in Figure 2, a conductive layer on the side surface is There are some that have an incision made in a part to form an independent pattern of insulation.

However, the above-mentioned conventional example has drawbacks such as a part of the through hole or the conductive layer peeling off when cutting the through hole or making an incision in a part of the side conductive layer. In particular, as the thickness of the substrate increases, it becomes difficult to cut through holes, and peeling of plating occurs frequently, resulting in a significant drop in product yield.

The present invention aims to solve the above-mentioned drawbacks of the prior art, and also enables higher density wiring on a printed wiring board and connection with external wiring,
It is an object of the present invention to provide a new printed wiring board and a method for manufacturing the same, which improves the degree of freedom in wiring design and makes it possible to expand the uses of the printed wiring board.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a printed wiring board and a method for manufacturing the same according to the present invention will be explained based on the drawings.

FIG. 3 is an enlarged perspective view of a portion of the printed wiring board of the present invention having a partially opened bent through hole in the side surface. In this drawing, a indicates the opening of a semi-through hole of a through hole provided on the front side of the printed wiring board,
b is a conductive portion formed by partially cutting and removing a through-hole semi-through hole provided from the back side where a portion of the hole provided from the side surface of the printed wiring board is opened. The term "semi-through hole" as used herein refers to a through hole a formed from the front side of the printed wiring board, as shown in the vertical cross-sectional view of FIG. 4 or the vertical cross-sectional view of FIG. 5, for example.
means a hole formed to a depth of approximately half the thickness of the substrate, and on the other hand, a through hole b formed from the back side of the substrate is a hole formed to a depth of approximately half the thickness of the substrate. It means something. These two holes, a and b, are always connected at a portion of each, forming a bent through-hole as a whole. However, the size, shape, and depth of the hole are not limited to those shown in FIGS. 4 and 5.

When the printed wiring board of the present invention shown in FIG. 3 or 4 is soldered to another board as shown in FIG. Because the capillary action reaches the top of the substrate, there is an advantage that not only can a reliable connection be made, but also that the connection state can be visually confirmed from the direction of the opening E.

As described above, according to the present invention, soldering can be performed easily, reliably, and quickly, and the reliability of soldering can be improved because solder frizz can be directly confirmed with the naked eye.

Next, an example of a method for manufacturing a printed wiring board according to the present invention will be described.

Figure 7 shows a printed wiring board, for example, a glass fiber epoxy resin board or a paper epoxy resin board with relatively thin metal foil such as copper foil laminated on both sides. FIG. 7 is a longitudinal cross-sectional view showing a state in which semi-through holes are formed so as to be connected, and a bent through hole is formed by connecting a portion of each hole. In this drawing,
a is a semi-through hole opened from the front side of the substrate, and b
is a semi-through hole opened from the back side of the board. and,
By connecting these holes a and b at a portion thereof, the entirety of these holes forms a bent through hole.

When making half-through holes on the front and back sides of the board, for example, as shown in FIG. 8 or 9, make sure that the centers of half-through holes a' and b' do not coincide. , and either a' or b' intersects the outer periphery of the printed wiring board, and the other holes are set so that they are inside the product. Further, the pore diameters of a' and b' can be made the same or different in size.

Further, regarding the positional relationship between a and b, it is desirable that the center of one circle be outside the circumference of the other circle from the viewpoint of ease of cutting.

In this way, in the printed wiring board of the present invention, holes of appropriate sizes and positions are formed by cutting with a drill or the like on the front and back sides of the printed wiring board, and these holes are part of each other. The holes are always connected, and the overall cross-sectional shape forms a through hole with a bent shape.

Next, after through-hole plating is applied to the bent through-holes to form a wiring pattern, as shown in Fig. 10, one hole that does not intersect with the outer periphery of the product is left as is, and the outer periphery is For example, other holes that intersect with the chain line Y-
Cut and remove a part of it along the chain line of Y′.

Next, FIG. 11 is a longitudinal cross-sectional view of the printed wiring board of the present invention in which a portion of either hole a or b has been cut and removed.

In addition, in the conventional method of manufacturing a printed wiring board, the operation of cutting and removing the holes described above requires cutting the through holes to the same length as the thickness of the board.

On the other hand, according to the method of the present invention, the cut portion of the through hole only needs to be cut by a portion of the thickness of the substrate that becomes the opening, that is, about half the thickness of the substrate, so the stress applied to the through hole during cutting is reduced. teeth,
This is extremely less than before, and peeling of the through-hole plating is significantly reduced.

Therefore, even if the thickness of the printed wiring board increases, the method for manufacturing a printed wiring board of the present invention can reduce the ratio of the opening to the thickness of the board.
It has the feature of being able to prevent a decrease in yield due to plating peeling off when cutting through holes.

When the printed wiring board of the present invention manufactured in this way is soldered to another board using a waver solder or reflow, the through hole in the bent shape with one part open on the side surface of the board can be used. Since the solder reaches the top of the board through the opening, continuous reliability on the side of the board can be easily confirmed visually from the opening.

On the other hand, as described above, the printed wiring board of the present invention can be opened by selecting arbitrary positions on the front side and the back side of the board to have sizes shifted from each other or the same diameter. This has the advantage that the degree of freedom can be improved.

Conventionally, as shown in Fig. 12, the pitch of the side conductive portion h of the printed wiring board was determined by the position of the wiring terminal g of another board, and the space between the wirings was fixed naturally. It was hot.

On the other hand, the printed wiring board of the present invention has a first
As shown in Figure 3, even if holes b are made from the back side at the same pitch as the wiring pitch for terminal g on other boards, the diameter and position of hole a from the front side can be freely adjusted within the range described above. Since the space required for component mounting and wiring can be expanded by changing the configuration, there is an advantage that the degree of freedom in designing for higher density wiring and component mounting can be improved.

[Brief explanation of the drawing]

1 and 2 are perspective views of a conventional printed wiring board, FIG. 3 is a perspective view of a printed wiring board of the present invention, FIG. 4 is a longitudinal sectional view of the printed wiring board of the present invention, and FIG. 5 is a perspective view of a conventional printed wiring board. FIG. 6 is a vertical cross-sectional view of an intermediate product of the printed wiring board of the present invention, FIG. 6 is a vertical cross-sectional view showing the solder connection state of the printed wiring board of the present invention, and FIG. 7 is a vertical cross-sectional view of the intermediate product of the printed wiring board of the present invention. A plan view, FIGS. 8 and 9 are relationship diagrams of the cutting positions of holes in the method of manufacturing a printed wiring board of the present invention, FIG. 10 is a longitudinal cross-sectional view also showing the cutting positions of holes, and FIG. vertical cross-sectional view of the printed wiring board of
FIG. 12 is a plan view of a conventional printed wiring board and external wiring terminals, and FIG. 13 is a plan view showing the positional relationship between the printed wiring board and external wiring terminals of the present invention.

Claims (1)

[Claims] 1. From the front side and back side of the printed wiring board,
A semi-through hole is made so that a portion of each hole is connected, and after applying through hole plating to the inner wall surface of the hole, one of the holes is left as it is,
A method for manufacturing a printed wiring board, comprising cutting and removing a portion of another hole. 2. A printed wiring board having a bent-shaped through-hole through-hole that is partially opened on the side surface of the printed wiring board.