JPH04346290A - Printed circuit board - Google Patents

Abstract

PURPOSE:To obtain a printed circuit board in which solder is scarcely connected to adjacent pad at the time of mounting a component so that a solder bridge scarcely occurs even if pads for mounting an integrated circuit component are provided at a narrow interval. CONSTITUTION:Pads 3 to be connected with leads of an integrated circuit component are formed in a recess state as compared with its periphery.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] This invention is particularly applicable to FP (flat
The invention relates to a printed wiring board on which ICs, LSIs, etc., which are packaged) are mounted.

0002

[Prior Art] A flat package (FP) is a package in which lead wires are brazed to the periphery of the package.It is small, the distance between the lead wires is small, and the shape is almost square, so the lead wires are They have the advantage of being almost equal in length and are widely used. The integrated circuit component to which this FP has been applied is mounted and used on a printed wiring board 1 shown in FIG.
Pads 2 for components are provided, and lead wires of the integrated circuit components are soldered to the pads 2 to mount the integrated circuit components on the printed wiring board 1.

FIG. 3 is an enlarged view of a portion A of the pad 2 in FIG. This pad 2 is formed to protrude upward from its surroundings, and the lead wires of the above-mentioned integrated circuit components are soldered to it. Moreover, the spacing between the pads 2 is provided at a narrow pitch as described above.

0004

[Problems to be Solved by the Invention] Conventional printed wiring boards are constructed as described above, and pads for FP components are provided at narrow intervals, so when soldering lead wires when mounting components, There was a problem in that solder easily applied to adjacent pads and solder bridges were likely to occur.

[0005] This invention was made to solve the above-mentioned problems, and its purpose is to obtain a printed wiring board in which solder bridging is less likely to occur when components are attached even if the pads are provided at narrow intervals. There is.

[0006]

SUMMARY OF THE INVENTION A printed wiring board according to the present invention has a pad to which a lead wire of an integrated circuit component is connected, and the pad is recessed from its surroundings.

[0007]

[Function] In the printed wiring board of the present invention, since the pads are formed to be recessed from their surroundings, it is difficult for adjacent pads to be covered with solder when soldering lead wires of integrated circuit components.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a perspective view showing an embodiment of the present invention, showing the shape of a pad 3 formed on a printed wiring board. This pad 3 is formed to be recessed from the surrounding area, and a lead wire of an integrated circuit component to which an FP has been applied is soldered to this pad 3. At this time, since the pad 3 is recessed, it is difficult for solder to apply to adjacent pads, and solder bridges are difficult to occur. Note that it is sufficient if the recess of this pad 3 is about several tens of microns.

[0009] Here, since the above-mentioned printed wiring board is formed by recessing the pad 3, it is necessary to manufacture it by an additive method. This method forms only through holes and necessary pattern parts by electroless plating, and is widely used together with the subtractive method using copper-clad laminates.

0010

[Effects of the Invention] As described above, according to the present invention, since the pads are formed in a recessed manner, when soldering the lead wires of integrated circuit components, it is difficult for the adjacent pads to be covered with solder.
Even if the pads are provided at narrow intervals, it is possible to obtain the effect that solder bridges are less likely to occur.

[Brief explanation of drawings]

[Fig. 1] A perspective view showing an embodiment of the present invention.

[Figure 2] A perspective view showing the appearance of a printed wiring board

[Fig. 3] Perspective view showing a conventional example

[Explanation of symbols]

1 Printed wiring board 3 Pad Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A printed wiring board characterized in that it has a pad to which a lead wire of an integrated circuit component is connected, and the pad is recessed from its surroundings.