JP2809519B2 - Wiring board device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring board device for mounting a multi-leg electronic component such as an IC and a method for soldering the same.

[0002]

2. Description of the Related Art Electrodes of a multi-leg electronic component are soldered to a plurality of lands provided on a wiring board device by various methods. In the solder dip soldering method, the amount of solder adhering between the lands adjacent to the rearmost land in the solder dip direction (substrate traveling direction) increases. That is, in the vicinity of the land which is finally separated from the solder blow-up portion, the solder does not pull backward because there is no subsequent land, and the amount of solder adhesion increases due to the surface tension of the solder. Therefore, a so-called solder bridge in which a plurality of electrodes of the multi-leg electronic component are short-circuited by solder is easily formed. Therefore, various methods have been conventionally proposed to prevent the formation of a solder bridge.

FIG. 4 shows an example of a conventional wiring board device S, which is configured as follows. Reference numeral 1 denotes a wiring board, on which the mounting surface 1a (the upper surface in FIG. 4) is a multi-legged electronic component, for example, SOP (Small Outline Package)
C4 is implemented. On the mounting surface 1a of the wiring board 1, SO
A plurality of lands 2 made of conductive foil are provided close to positions corresponding to a plurality of electrodes 5 led out from both sides along the longitudinal direction of the PIC 4.

Further, of the plurality of lands 2, unnecessary solder removing lands (hereinafter referred to as “abandon lands”) are provided behind a rearmost land 2 a (the rightmost land in the figure) which lastly enters the solder blow-up portion during soldering. 3) is provided. The waste land 3 is also formed on the same plane as the other land 2 (2a), and is integrally provided with the rearmost land 2a in a U-shape.

In order to mount the SOPIC 4 on the wiring board 1, the SOPIC 4 is first mounted at an appropriate position on the mounting surface 1a. Next, as shown in FIG. 5, the mounting surface 1 is placed on the solder blow-up portion X where the molten solder is blown up and held in a fixed width.
a so as to face each other, and each electrode 5 of the SOPIC 4
Is soldered to the corresponding land 2 (2a).

In such a conventional wiring board device S, the rearmost land 2a which lastly enters the solder blow-up portion X
Is provided behind the land, so the land 3
The solder is pulled up to the part. Therefore, the solder is uniformly and appropriately applied between the lands 2 (2a) preceding the waste land 3, and the plurality of electrodes 5 of the SOPIC 4 corresponding to the vicinity of the last land 2a are soldered and short-circuited. Is less likely to occur.

[0007]

However, the disposal land 3
Is lower than the lead-out portion (base portion) 5a of the electrode 5 of the SOPIC 4 from the package, so that the waste land 3 separates from the solder blow-up portion X earlier than the base portion 5a of the electrode 5 corresponding to the rearmost land 2a. That is, the solder attached to the base 5a of the electrode 5 corresponding to the rearmost land 2a is not discarded to the land 3, and the amount of solder attached near the electrode 5 increases.
Therefore, it has been difficult to completely prevent the occurrence of a solder bridge. FIG. 6 shows an example in which a solder bridge has occurred.

Accordingly, an object of the present invention is to appropriately prevent the occurrence of a solder bridge.

[0009]

According to the present invention, there is provided a wiring board device, wherein a plurality of lands for connecting electrodes of a multi-leg electronic component are continuously provided on a wiring board, and an extension connecting the plurality of lands is provided. Has a soldering surface higher than the land surface on the line,
A ring-shaped extending member is provided in a side view.

[0010]

[0011]

According to the present invention, since the extension member 6 having the solder attachment surface 6a higher than the land surface is provided behind the rearmost land 2a, the extension member 6 is arranged closer to the rearmost land 2a.
It leaves the molten solder (for example, in the flow method of the dip method, the solder blow-up portion X) later than the electrode 5 corresponding to a. In other words, since the solder attachment surface 6a of the extension member 6 is dipped to the end, the solder is drawn to the solder attachment surface 6a. Furthermore, since the extension member has a ring shape,
The solder is pulled into the hole of the ring, and the suction of the solder is good. Therefore, the land 2 preceding the rearmost land 2a
In between, the solder is uniformly and appropriately applied. Therefore, the occurrence of a solder bridge between the plurality of electrodes 5 of the multi-foot electronic component 4 corresponding to the vicinity of the rearmost land 2a is prevented.

[0012]

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. In FIG. 1, portions corresponding to those in FIG. 4 are denoted by the same reference numerals, and detailed description thereof will be omitted. As shown in FIG. 1, the rear end land 2a is formed to extend rearward by a predetermined distance and to be long. An extension member 6 having a solder attachment surface 6a higher than the land surface is provided continuously to the rear end of the last land 2a. As shown in FIG. 1, the extension member 6 has a substantially rectangular ring shape, and may be mounted simultaneously when the SOPIC 4 is mounted. The height T of the extension member 6 is set such that the base 5a of the electrode 5 corresponding to the rearmost land 2a separates from the solder blow-up portion X earlier than the extension member 6.

As shown in FIG. 2, the angle of entry of the wiring board 1 into the solder blow-up portion X is θ, the height of the base 5a of the electrode 5 corresponding to the land 2 (2a) is H, and the last land 2a is Assuming that the distance from the extending member 6 is L, the height T of the extending member 6 is
For example, it is set so as to satisfy Expression (1).

T ≧ H−Ltan θ (1) As is clear from the equation (1), L can be reduced by setting T to be larger. This example is configured as described above, and the rest is configured similarly to the example of FIG.

In this embodiment, a SOPIC is mounted on the wiring board 1.
In order to mount the SOPIC 4, the SOPIC 4 is first mounted at an appropriate position on the mounting surface 1a. Next, as shown in FIG. 2, the mounting surface 1a is made to protrude at a predetermined inclination angle θ so as to face the solder blow-up portion X, and each electrode 5 of the SOPIC 4 is soldered to the corresponding land 2 (2a). I do.

In this embodiment, the rear end land 2a has a solder attachment surface 6a higher than the land surface, and the ring-shaped extending member 6 is provided in a side view.
Is separated from the solder blow-up portion X later than the base 5a of the electrode 5 corresponding to the rearmost land 2a. That is, since the solder attachment surface 6a of the extension member 6 is dipped to the end, the solder is pulled down to the solder attachment surface 6a, and the solder between the electrode 5 corresponding to the rearmost land 2a and the extension member 6 is extended. Solder is attached to the entire end land 2a (see FIG. 3). At this time, since the extending member 6 has a ring shape, the solder is pulled into the hole of the ring by the ring shape,
The solder absorption is good, so that more solder is
To be easily adhered to. Therefore, there is little extra solder between the lands 2 preceding the last land 2a, and the solder is uniformly and appropriately applied. Therefore, according to this example,
The occurrence of a solder bridge between the plurality of electrodes 5 of the SOPIC 4 corresponding to the vicinity of the rearmost land 2a can be favorably prevented.

Further, in this embodiment, since the wiring board device S is caused to protrude into the solder blow-up portion X at a predetermined inclination angle θ, the extension member 6 is more extended than the base 5a of the electrode 5 corresponding to the rearmost land 2a. It becomes easier to separate from the solder blow-up portion X later. Therefore, according to the present example, solder bridges between the plurality of electrodes 5 of the SOPIC 4 corresponding to the vicinity of the rearmost land 2a can be more reliably prevented.

For the height T of the extension member 6, the rush angle θ with respect to the solder jetting part X is 6 °, and the base 5 of the electrode 5
According to the experiment result in which the height H of the extension member 6 was set to 1.5 mm and the distance L between the rearmost land 2a and the extension member 6 was set to 2 mm in advance, when the height T of the extension member 6 was 0.4 mm, five times As a result, seven solder bridges were formed. In the case where the height T of the extension member 6 was 1.25 mm, no solder bridge was formed even after 12 rushes.

The extension member 6 in the above embodiment may be a component related to an IC. The point is that the extension member 6 can be similarly applied as long as it has a solder attachment surface 6a higher than the land surface. Although the multi-leg electronic component is an example of SOPIC4, the present invention relates to a QFP (Quad Flat Packag).
e) The present invention can be applied to a case where a multi-leg electronic component such as an IC is mounted.

[0021]

According to the present invention, a ring-shaped extension member is provided behind the last land and has a solder attachment surface higher than the land surface, so that the solder attachment surface of the extension member is dipped to the end. Then, by drawing the solder to the portion where the solder is attached, the occurrence of a solder bridge between the plurality of electrodes of the multi-foot electronic component corresponding to the vicinity of the rearmost land can be satisfactorily prevented. In addition, since the extension member has a ring shape, when the solder is dipped, the ring shape pulls the solder into the hole of the ring, and the solder is well absorbed, so that more solder is attached to the extension member. It will be easier. Therefore, there is little excess solder between the lands preceding the last land, and the solder is applied more uniformly and in an appropriate amount, so that the occurrence of a solder bridge can be reliably prevented.

[0022]

[Brief description of the drawings]

FIG. 1 is a perspective view of an embodiment.

FIG. 2 is a diagram showing a state during soldering of the embodiment.

FIG. 3 is a view showing a state after soldering in the embodiment.

FIG. 4 is a perspective view of a conventional example.

FIG. 5 is a view showing a state during soldering of a conventional example.

FIG. 6 is a diagram showing a state after soldering in a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wiring board 2 Land 2a Last end land 4 SOPIC 5 Electrode 5a Base 6 Extension member 6a Solder attachment surface S Wiring board device X Solder jetting part θ Tilt angle

Claims (1)

(57) [Claims] 1. A plurality of lands for connecting electrodes of a multi-leg electronic component are continuously provided on a wiring board, and a solder attachment surface higher than a land surface is provided on an extension line connecting the plurality of lands, A wiring board device comprising a ring-shaped extending member provided in a side view.