JPH04296094A - Multilayer wiring board - Google Patents

Abstract

PURPOSE:To enable a surface mounting multilayer wiring board to be enhanced in mounting and wiring density. CONSTITUTION:A through-hole 2 whose diameter is smaller than the width of a pad 1 is provided to the surface-mounting type component mounting pad 1 to connect a pad section to an inner pattern. The lead 3 of the surface- mounting type component and the surface-mounting type component mounting pad 1 are electrically connected together through the through-hole 2. A through- hole which is provided outside a surface-mounting component mounting pad and usually required for the connection of a surface-mounting type component mounting pad to an inner pattern is not required, and thus a multilayer wiring board of this design can be enhanced in mounting and wiring density.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer wiring board, and particularly to a multilayer wiring board that employs surface mounting and is suitable for high-density wiring.

0002

[Prior art] As a conventional technology, Japanese Patent Application Laid-Open No. 60-57
As described in Japanese Patent No. 999, there is a method in which an imposition pad is provided on the inner layer pattern and that portion is exposed, thereby eliminating the need for a through hole for connecting the imposition pad and the inner layer pattern.

0003

[Problems to be Solved by the Invention] The above-mentioned prior art does not take into account high-density wiring of inner layer patterns;
There was a problem in that the inner layer pattern could not be wired with high density because the surface mounting pad was present in the inner layer. In addition, in the case of a multilayer wiring board that has a power supply layer and a ground layer on the inner layer,
The connection between the inner layer pattern below the power layer and ground layer and the surface mounting pad requires a through hole for conventional connection.
There was a problem that high-density mounting and wiring were not possible.

An object of the present invention is to provide a multilayer wiring board on which circuit patterns can be wired with high density.

[0005]

[Means for solving the problem] The above purpose is as shown in Figures 1 and 2.
This is achieved by providing a through-hole with a diameter smaller than the pad width for connecting the pad portion and the inner layer pattern to the surface-mounted component mounting pad, as shown in FIG.

[0006]

[Function] By providing a through hole with a diameter smaller than the pad width to connect the pad part and the inner layer pattern to the surface mounting pad, the surface mounting pad is not needed on the inner layer, so the inner layer pattern can be raised. It becomes possible to wire densely.

[0007] Also, in a multilayer wiring board that has a power supply layer and a ground layer on the inner layer, when connecting the inner layer pattern further below the power supply layer and the ground layer to the surface-mounting pad, it is also possible to use a connection other than the conventional surface-mounting pad. This eliminates the need for through-holes, allowing for high-density mounting and wiring.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a sectional view showing an embodiment of a multilayer wiring board according to the present invention. A through hole 2 having a diameter smaller than the pad width is provided in a surface-mounted component mounting pad 1 for connecting a pad part and an inner layer pattern. The lead 3 of the surface-mounted component and the surface-mounted component mounting pad 1 are electrically connected by soldering 4. The surface-mounted component mounting pad 1 and the inner layer pattern 5 are electrically connected through a through hole 2. With the above configuration, a through hole outside the surface-mounted component mounting pad, which was conventionally necessary to connect the surface-mounted component mounting pad and the inner layer pattern, becomes unnecessary. This makes it possible to mount surface-mounted components and wire patterns even in narrow areas where conventionally there was no area for through-holes and wiring was impossible.

[0009] Also, as mentioned in the conventional technique, by providing surface-mounted component mounting pads on the inner layer pattern and exposing the components, the through-holes for connecting the surface-mounted component mounting pads and the inner layer pattern can be eliminated. In the case of this method, since pads for surface-mounted component mounting are present on the inner layer, it is impossible to wire a pattern on the inner layer at the pad portion, which becomes a wiring bottleneck.

On the other hand, in the present invention, the pad for mounting surface-mounted components is provided on the outer layer, so it is possible to wire the pattern on the inner layer below the pad for mounting surface-mounted components, as shown in FIG. Good wiring efficiency.

In addition, in the case of the method mentioned in the conventional technology, in a multilayer wiring board having a power supply layer and a ground layer on the inner layer, the pattern of the layer further below the power supply layer and the ground layer and the surface-mounted component mounting pad are In order to make the connection, a through hole for connection is required. In contrast, in the present invention, as shown in FIG. 1, the patterns further below the power supply layer 6 and ground layer 7 and the surface-mounted component mounting pad are connected by small-diameter through holes provided in the surface-mounted component mounting pad. Therefore, a through hole outside the surface-mounted component mounting pad for connecting the surface-mounted component mounting pad and the inner layer pattern is not required.

0012

According to the present invention, there is no need to provide a through hole outside the surface-mounted component mounting pad for connecting the surface-mounted component mounting pad and the inner layer pattern. Since there is no need to provide mounting pads, surface-mounted components can be mounted and patterns can be wired even in a narrow area.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a multilayer wiring board according to an embodiment of the present invention.

FIG. 2 is a plan view of a multilayer wiring board according to an embodiment of the present invention.

[Explanation of symbols]

1...Pad for mounting surface-mounted components, 2...Through hole, 3...Lead, 4...Solder, 5...Inner layer pattern, 6...Power layer, 7...Ground layer.

Claims (1)

[Claims] 1. A multilayer wiring board characterized in that a via hole having a diameter smaller than the pad width is provided in a surface-mounted component mounting pad for connecting a pad portion and an inner layer pattern.