JPS59158582A - Both-side circuit board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Technical field The present invention relates to a double-sided wiring board.

BACKGROUND ART Conventional double-sided wiring boards have through holes formed in the board, and wiring patterns on both sides of the board are connected through these holes.

1~Kashibu J), in this board, the connection part at the through hole of the mounting pattern or the wiring glue IIF
This resulted in restrictions during pattern formation, and it was not possible to achieve wiring with reasonable density.

In addition, conventional through-hole connections have been carried out either chemically by plating or physically by using adhesive paint.3. Since it has the disadvantage of being very complicated compared to A'J'l's scientific method, the physical method described below is often adopted. .

However, the above-mentioned physical method has the disadvantage that the conductive paint applied to the through-hole ζ becomes thinner at the edge of the hole, making the connection unstable. 11th fj
(A) to (G) are diagrams showing the manufacturing process of a double-sided wiring board using the conventional physical through-hole connection method.
The entire one side of tA' 1 (a through hole 3 is drilled in the base (a) on which the metal foil 2 is laminated), and an etching resist 4 is applied to the metal foil 2-L to pattern the wiring c) After removing unnecessary metal foil portions by etching (d), the etching cleanst layer 4 is further removed to form a single-sided wiring board (e).

Next, conductive paint such as Ag paste is poured into the through holes 3 by screen printing, and the jumper conductive parts 5 connecting the patterns on both sides of the board are formed. As shown in the figure, a conductive paint such as carbon paste is applied by screen printing to form a wiring pattern 6 (g).

Conventionally, double-sided wiring boards are formed in this way,
According to this method, among the jumper conductive portions 5 formed by applying Ag paste or the like to the through holes 3, the edge portions 7 of the substrate 1 (see FIG. This is the cause of the occurrence of
) i'' The Δg paste 5 is applied to a predetermined width around the through hole 3, and since this diameter is inevitably larger than the width of the wiring pattern 6, there are restrictions during pattern formation, and it is not possible to make a rational and highly reliable method. It has the disadvantage that it is not possible to carry out wiring.

<Purpose> The present invention was made in view of these conventional drawbacks, and it is an object of the present invention to provide a new double-sided wiring board that not only improves the reliability of through-hole connections but also enables rational and high-density wiring. It is something to do.

<Example> The present invention will be explained in detail below based on the drawings.

FIGS. 3(a) to 3(b) are diagrams showing the manufacturing process of the double-sided wiring board according to the present invention. The substrate of the present invention has through holes (
The whole surface of the base material 8 is made of a substrate material laminated with metal foil, etc., so as to cover the through holes. For example, a through pole (merely a through hole) 9 having a diameter comparable to the width of the wiring pattern is drilled at a predetermined position in a portion corresponding to the wiring pattern to be formed. A metal foil 10 is laminated to cover the through hole 9 (opening). Note that it is convenient to drill guide holes for processing such as etching resist printing at the same time as forming the through holes.

Then, an etching resist 11 is formed on the metal foil 10.
is applied to draw the wiring pattern, and at the same time the surface of the base material 8 (
After applying an etching prevention tape 12 to the entire bottom surface (in the figure), an etching process is performed (2), and the etching resist 11 and 12 are removed to form a single-sided wiring board (2). In this case, one opening of the through pole 9 is closed by a wiring pattern made of metal foil [0'].

Next, the single-sided wiring board formed in this way (as shown in the figure (H)) is
The wiring pattern 13 is formed by applying a conductive paint such as carbon paste by screen printing from the surface (the side on which the wiring pattern by metal foil 0' is not formed) of the metal foil 0'. At this time, the conductive paint enters the through hole 9 and adheres to the wiring pattern IO' formed on one side of the base material 8, thereby electrically connecting the direction pattern IO' and 13. A double-sided wiring board is formed.

To solve the problem with the double-sided wiring board constructed in this way, as shown in FIG. 2 6), conductive paint is embedded in the through holes 9i and the paint is applied so as to pass over the embedded portions to form the wiring pattern I3. Since the wiring pattern 10 is electrically connected to the other wiring pattern 10, there is no risk of the paint becoming thinner at the etched portion of the through hole 9, and a good connection can always be obtained.

Also, as shown in Figure 4, since the wiring patterns on both sides are connected with the conductive paint embedded in the through-hole 9 sandwiched between them, the diameter of the through-hole 9 should be approximately the same as the wiring pattern. It can be adjusted to fit the width, so the connecting portion with the through hole 9 does not become as large as shown in FIG.

<Effects> As described above, according to the uninvented double-sided wiring board, it is possible to greatly improve the reliability of through-hole connections, and at the same time (
This allows for rational, high-density wiring.

[Brief explanation of the drawing]

Fig. 1A-17T+ is a diagram showing the manufacturing process and its structure of the conventional board, Fig. 2 is a plan view of the main part of the same board, and Figs. A diagram showing the process and its structure, and FIG. 4 is a plan view of the main part. 8 is a base material, 9 is a through-hole plate, 1o is a metal foil, 11 is an etching resist, and IO2 and 13 are wiring patterns.

Claims (1)

[Claims] I Form a through hole (on one side of the substrate, form a wiring pattern so as to cover the through hole (7), and form a wiring pattern on the other side by burying the through hole) A double-sided wiring board that depends on what you do!