JPH0526784Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention relates to a printed wiring board to which electronic components having multiple lead terminals such as integrated circuits (ICs) and large-scale integrated circuits (LSIs) are soldered. It is.

[Summary of the idea]

This idea is to solder the outermost soldering land of the soldering land row in a printed wiring board that is provided with a soldering land row for soldering electronic components having a large number of lead terminals. By forming the soldering land part wide in the extending direction of the soldering land row and adhering it on the insulating substrate, and separating the soldering land part and the surplus soldering land part with a solder resist layer, the soldering land part is made wide in the extending direction. This prevents solder bridging from occurring and also prevents excess solder land from peeling off.

[Conventional technology]

In recent years, electronic components having multiple lead terminals, such as highly integrated ICs and LSIs, have been used in various circuits. A large number of lead terminals of such an electronic component are soldered to soldering lands of a printed wiring board on the same plane.

When soldering each lead terminal of an electronic component as described above, overlap each lead terminal with the soldering land provided in advance on the printed wiring board,
A soldering iron with a large amount of solder attached to the tip is slid in a straight line along the row of soldering lands, and each lead terminal is soldered to each corresponding soldering land. When each lead terminal is soldered in this way, the soldering work can be performed faster than when soldering the lead terminals one by one.

However, at the moment when the soldering iron leaves the last soldering land, a large amount of solder remains on the last soldering land due to surface tension. There was a problem in that solder bridges were formed between the two, resulting in a short circuit.

Therefore, a printed wiring board having a pattern that prevents solder bridges from occurring between soldering lands has been proposed.

FIG. 4 is a plan view showing the above-mentioned printed wiring board (Japanese Utility Model Publication No. 57-44699), in which reference numeral 11 indicates the printed wiring board, and on the upper surface of the insulating board 12 there is a wiring pattern 13 and an excess solder land. (hereinafter simply referred to as the land portion) 14 is provided,
A part of the wiring pattern 13 is a soldering land portion (hereinafter simply referred to as a land portion) 13L, and a land portion 14 is arranged on a line connecting the land portions 13L.

P indicates an electronic component, and a large number of lead terminals L are provided.

SI indicates a soldering iron, and S indicates solder attached to the tip of the soldering iron SI.

Printed wiring board 11 configured as above
As mentioned above, the wiring pattern 1 prepared in advance is
The lead terminal L of the electronic component P is attached to the land portion 13L of 3.
are placed one on top of the other, and the soldering iron SI with a large amount of solder S attached to the tip is slid in a straight line in the direction of the arrow as if stroking along the land portion 13L, and each lead terminal L is attached to the corresponding land portion 13L. Solder.

When the soldering iron SI is moved to the land portions 14 and then separated from the printed wiring board 11, the remaining excess solder adheres to the land portions 14 due to surface tension, and no solder bridges occur between the land portions 13L.

[Problem that the invention attempts to solve]

However, in recent years, the printed wiring board 11 has become more densely packaged, and the space between the wiring patterns 13 has become smaller, and the land portions 13L,
The area of 14 tends to decrease.

Therefore, the adhesive strength between the insulating substrate 12 and the land portion 14 is weakened, and the land portion 14 is attached to the insulating substrate 1.
There is a risk that it may peel off from the 2nd layer and adhere to the conductive parts of the circuit, causing a short circuit accident.

Also, the land portion 13L closest to the land portion 14
is the place where the most force is applied when removing the electronic component P, and it is desired to increase the adhesive strength with the insulating substrate 12 by making the area larger than the other land parts 13L, but considering high-density mounting, it is necessary to increase the area. The problem is that it cannot be made larger.

This invention provides a printed wiring board that solves the above-mentioned problems.

[Means for solving problems]

In the printed wiring board of this invention, the outermost soldering land of the soldering land row is formed wide in the direction of extension of the soldering land row, and is bonded to an insulating substrate, and is coated with a solder resist layer. It is separated into a soldering land portion and an excess soldering land portion.

[Effect]

In the printed wiring board of this invention, excess solder adheres to the surplus solder lands, thereby preventing the occurrence of solder bridging.

Further, since the soldering land portion and the surplus soldering land portion are integrally bonded to the insulating substrate, the adhesion strength of the soldering land portion consisting of both land portions to the insulating substrate is strengthened.

〔Example〕

FIG. 1 is a plan view showing an embodiment of the printed wiring board of this invention, and FIG. 2 is an enlarged plan view showing the main parts of FIG.

In these figures, reference numeral 1 denotes a printed wiring board, and wiring patterns 3 and 4 are formed on the upper surface of an insulating substrate 2, with parts of the wiring patterns 3 and 4 forming soldering lands (hereinafter simply referred to as lands). )3L,
It is said to be 4L. The land portion 4L is formed to be wide in the extending direction connecting the land portions 3L, and the solder resist layer 5 shown by hatching has a soldering land portion (hereinafter simply referred to as a land portion) 4LL and surplus solder. land part (hereinafter referred to as
It is simply called the land part. ) 4LS.

Since the printed wiring board 1 of this invention is constructed as described above, when electronic components are soldered as described above, the excess solder from soldering the lead terminals L is collected on the land portion 4LS. Therefore, an appropriate amount of solder adheres to the lead terminal L, and the occurrence of solder bridging can be prevented.

Since the land portions 4LL and 4LS are integrally bonded to the insulating substrate 2, the adhesive strength is stronger than that of the land portion 3L, and the land portion 4L, which is subjected to the most force when removing the electronic component P, is difficult to peel off. Become.

Further, even if the land portion 4L is peeled off from the insulating substrate 2, it is connected to the wiring pattern 4, so there is no possibility that it will fall off and adhere to the conductive portion of the circuit, causing a short circuit accident.

Further, since the land portion 4LL and the land portion 4LS are separated by the solder resist layer 5, the solder that has reached the land portion 4LS is difficult to return to the land portion 4LL.

FIG. 3 is an enlarged plan view similar to FIG. 2 showing the main parts of another embodiment of the invention, and the same reference numerals as in FIGS. 1 and 2 indicate the same parts.

In FIG. 3, reference numeral 6 indicates a wiring pattern provided on the upper surface of the insulating substrate 2, a part of which is used as a soldering land portion 6L. The soldering land portion 6L is formed in a shape with a narrow middle part and a wide width in the extending direction connecting the land portions 3, and the soldering land portion 6LL is formed with the solder resist layer 5 as in the embodiment shown in FIG. It is separated into a surplus solder land portion 6LS.

Although this embodiment differs from the embodiment shown in FIG. 1 in the shape of the soldering land portion 6L, similar effects can be obtained.

[Effect of idea]

As explained above, in the printed wiring board of this invention, the outermost soldering land of the soldering land row is formed wide in the extending direction of the soldering land row and is bonded onto the insulating substrate. At the same time, since this part is separated into a soldering land part and a surplus solder land part by the solder resist layer, the surplus solder adheres to the surplus solder land part, thereby preventing the occurrence of solder bridging.

Further, since the soldering land portion and the unnecessary soldering land portion are bonded to the insulating substrate as the soldering land portion, the adhesion strength of both land portions to the insulating substrate is strengthened.

Furthermore, even if the soldering land consisting of both lands peels off from the insulating board, it is still connected to the wiring pattern, so there is no risk of it falling off and adhering to the conductive part of the circuit, causing a short circuit. There are advantages.

[Brief explanation of drawings]

Fig. 1 is a plan view showing one embodiment of the printed wiring board of this invention, Fig. 2 is an enlarged plan view showing the main parts of Fig. 1, and Fig. 3 shows the main parts of another embodiment of this invention. FIG. 4 is an enlarged plan view showing a conventional printed wiring board. In the figure, 1 is a printed wiring board, 2 is an insulating board,
3 and 4 are wiring patterns, 3L and 4L are soldering land parts, 4LL is soldering land parts, 4LS
5 is a surplus solder land portion, 5 is a solder resist layer, P is an electronic component, and L is a lead terminal.

Claims (1)

[Scope of utility model registration request] In a printed wiring board in which rows of soldering lands are arranged in parallel to electrically connect a large number of lead terminals of electronic components on the same plane, the outermost soldering land of the rows of soldering lands. is formed to have a wide width in the extending direction of the row of soldering lands and is bonded onto an insulating substrate, and the soldering lands are used as soldering lands to which the lead terminals are soldered using a solder resist layer. , a printed wiring board characterized in that it is separated from a land portion for surplus solder.