JPH05267851A - Multilayer printed circuit board - Google Patents

Abstract

PURPOSE:To eliminate formation of an excess penetrating through hole and to enhance mounting density of a component by providing a non-penetrating through hole in an inspection pad electrically connected to a pad of an LSI in a multilayer printed circuit board in which a surface mounting type LSI is placed. CONSTITUTION:A multilayer printed circuit board 1 has an inspection pad 4 electrically connected to a pad 2 of an LSI, and comprises a non-penetrating through hole 5 in the pad 4. The hole 5 is electrically connected to an inner pattern 6 of the board 1. Incidentally, the hole 5 is provided in the pad 4 electrically connected to the pad 1, and may be electrically connected to a component pad to be placed on an opposite side surface to the placing surface of an LSI. Thus, necessity of providing an excess penetrating through hole land on the board 1 is eliminated, mounting density of the component on the board 1 is improved, and a wiring efficiency is improved.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a multilayer printed wiring board,
In particular, the present invention relates to a multilayer printed wiring board having an inspection pad electrically connected to an LSI pad.

[0002]

2. Description of the Related Art With the recent miniaturization and high density of electronic equipment, LSI packages used have been surface-mounted and lead pitches have been narrowed. Along with that,
In the connection inspection of the printed wiring board, the LSI pad cannot be used as the inspection point for the surface-mounted LSI portion. Therefore, as shown in FIG. 3, the inspection pad 4, which is electrically connected to the LSI pad 2, Alternatively, the through-hole land 8 is provided and used as an inspection pad.

When the pattern passing through the inspection pad 4 of the LSI is connected to the opposite surface of the inspection pad or the inner layer, as shown in FIG. 4, the through-hole land 8 is also formed on the opposite surface of the inspection pad 4. Will be formed,
The through hole lands 8 hinder the arrangement of the component pads 7 on the opposite surface of the inspection pad 4 and the formation of the wiring pattern 3.

[0004]

In this conventional multilayer printed wiring board, when the mounting density of the components or the pattern wiring density becomes high, the inspection pad or the through-hole land is on the opposite surface of the inspection pad. There is a problem that it hinders the arrangement of pads for components and the formation of wiring patterns, and deteriorates the mounting density and wiring efficiency.

An object of the present invention is to provide a multi-layer printed wiring board having high packaging density and high wiring efficiency.

[0006]

The present invention provides a multilayer printed wiring board on which a surface mounting type LSI is mounted, wherein the LS
A non-through hole is provided in the inspection pad electrically connected to the I pad.

[0007]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a sectional view of the essential portions of the first embodiment of the present invention.

In the first embodiment, as shown in FIG.
Inspection pad 4 electrically connected to I pad 2
In the multilayer printed wiring board 1 having the above, non-through through holes 5 are provided in the inspection pad 4 so as to be electrically connected to the inner layer pattern 6 of the multilayer printed wiring board 1.

FIG. 2 is a sectional view of the essential portions of the second embodiment of the present invention.

In the second embodiment, as shown in FIG. 2, a non-penetrating through hole 5 is provided in the inspection pad 4, and a component pad 7 mounted on the surface opposite to the mounting surface of the LSI. It has an electrical connection.

[0012]

As described above, according to the present invention, by providing a non-penetrating through hole in the inspection pad electrically connected to the LSI pad, an extra penetrating through hole land is formed on the multilayer printed wiring board. It is possible to eliminate the need to provide. Therefore, it is effective in improving the mounting density of components on the multilayer printed wiring board and in improving the wiring efficiency.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a main part of a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of essential parts of a second embodiment of the present invention.

FIG. 3 is a plan view of an inspection pad connected to a pad of a conventional LSI.

FIG. 4 is a cross-sectional view of essential parts of an example of a conventional multilayer printed wiring board.

[Explanation of symbols]

 1 Multilayer Printed Wiring Board 2 Pad 3 Wiring Pattern 4 Inspection Pad 5 Non-Through Through Hole 6 Inner Layer Pattern 7 Component Pad 8 Through Through Hole Land

Claims (1)

[Claims] 1. A multilayer printed wiring board on which a surface-mounting type LSI is mounted, wherein a non-through hole is provided in an inspection pad electrically connected to a pad of the LSI. Wiring board.