JPH04101496A - Printed wiring board - Google Patents

Abstract

PURPOSE:To improve the bonding of a pad on base material by providing reinforcing pads which are locally extended from the edge of the pad which mounts surface mounting components. CONSTITUTION:Reinforcing pads 5 are provided at the five parts at the edge of a pad 3 which is connected with a pattern 6. A solder resist 4 is separated from the pad 3, however, the resist 4 is provided so as to cover partly the reinforcing pads 5 by screen printing or photo printing. Thus, the reinforcing pads 5 are formed at two parts or more, the pattern 6 is permitted to be turned easily and dense wiring can be performed. The adhesion of the whole pad to a base material is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a printed wiring board, and particularly to the structure of a pad on which a surface mount component is mounted.

[Conventional technology]

Conventionally, in the structure of printed wiring boards that carry surface mount components,
As shown in FIG. 3(a), the pad 3 connected to the pattern 6 has a circular shape, or as shown in FIG. 3(c), the pad 3 connected to the pattern 6 has a polygonal shape. I was doing it. In FIGS. 3(a) and (C), pad 3
The solder resist 4 is placed on the base material 2 and the pattern 6 by two-screen printing or photo printing around the pad 3 without covering the pad 3. FIG. 3(b) is a sectional view taken along line c-c' in FIG. 3(a). In FIG. 3(b), a pad 3 is disposed on the main surface of the base material 2 of the printed wiring board 1, and a solder resist 4 is disposed on the base material 2 around the pad 3. ing. Also in Figure 3(d),
This is the same as the case in FIG. 3('b).

[Problem to be solved by the invention]

The pads 3 of the conventional printed wiring board described above are susceptible to mechanical stress when surface mount components are attached and mounted by soldering etc., inspections during installation of other mechanical components after surface mount components are mounted, electrical circuit tests, etc. The stress of the jig adds stress that causes it to be peeled off from the base material 2, but in recent years, surface mount components have been mounted on printed wiring boards with high density, and the size of the pads on printed wiring boards has become smaller. 0. smaller than an area of 1 mm2.
5φ~0.7φ diameter) (0,5~0.7)X (0,
5-0.7) mrn2 has appeared. Therefore,
Since the adhesive area between the pad 3 and the base material 2 is small, the pad 3 and the base material 2 may be easily peeled off due to the mechanical stress described above, resulting in a problem of low connection reliability.

An object of the present invention is to provide a printed wiring board that solves the above problems and improves the adhesiveness between the pad and the base material.

[Means to solve the problem]

The structure of the present invention is characterized in that, in a printed wiring board having a pad on which a surface-mounted component is mounted, a reinforcing pad is provided that locally extends from the edge of the pad.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1(a) is a plan view of a printed wiring board according to a first embodiment of the present invention, and FIG. 1(b) is a sectional view taken along line A-A'.

In FIG. 1(a) and FIG. 1(b), in this embodiment, reinforcing pads 5 are provided at five locations on the edge of the pad 3 connected to the pattern 6.

The solder resist 4 has no pad 3, but
It is disposed so as to partially cover the reinforcing pad 5 by screen printing or photo printing. A pad 3 is disposed on a base material 2 of a printed wiring board 1, and a reinforcing pad 5 is disposed next to it, and a solder resist 4 is disposed on a part of the surface of the reinforcing pad 5. Figure 1(c) is the same as Figure 1(a).
FIG. 2 is a plan view showing a second embodiment in which the pad 3 has a polygonal shape, and other parts are the same as FIG. 1(a).

FIG. 1(d) is a cross-sectional view taken along line B-B' in FIG. 1(c).
This is similar to FIG. 1(b).

FIG. 2(a) is a plan view showing a third embodiment of the present invention;
FIG. 2(b) is a plan view showing a fourth embodiment of the present invention. In each of these embodiments, reinforcing pads 5 are formed at two locations, which allows the pattern 6.6'' to be easily rolled around, which has the advantage of allowing high-density wiring.

〔Effect of the invention〕

As described above, the present invention has the effect of increasing the adhesion strength of the entire pad to the base material by arranging the reinforcing pad at the edge of the pad on which the surface mount component is mounted. In particular, since a portion of the reinforcing pad is covered with a solder resist, it has the effect of having high peeling resistance even against directional peeling stress. This effect is particularly significant when the area of the pad is smaller than 1 mrn2.

FIG. 3 (a> is a plan view showing an example of a conventional printed wiring board;
FIG. 3(b) is a cross-sectional view taken along line c-c' in FIG. 3(a), FIG. 3(C) is a plan view showing the other side of the conventional technology, and FIG. It is a sectional view of line DD' of c).

DESCRIPTION OF SYMBOLS 1... Printed wiring board, 2... Base material, 3... Pad,
4...Solder resist, 5...Reinforcement pad, 6.
6'...pattern.

Claims (2)

[Claims] 1. 1. A printed wiring board having a pad on which a surface-mounted component is mounted, characterized in that a reinforcing pad is disposed locally extending from an edge of the pad. 2. The printed wiring board according to claim 1, wherein the reinforcing pad is partially covered with a solder resist.