JPH04245694A - Wiring board device and soldering method thereof - Google Patents

Abstract

PURPOSE:To prevent the generation of solder bridge satisfactorily when mounting multi-leg electronic components on a wiring board. CONSTITUTION:A plurality of lands, which are designed to connect electrodes 5 of an SOPIC 4, are continuously installed to a wiring board 1. The land 2a located at the farthest rear is selected out of the lands 2 and further extended. There is installed an extension material 6 having a solder-adhered side 6a higher than the land surface on the rear end continuously. This wiring board 1 is dipped into a solder ejection section at a specified slanting angle to be soldered. During this soldering work, the solder adhering side 6a of the extension member 6 is dipped to the end. In other words, the solder is stretched up to the part of the solder adhering side 6a so that the solder may adhere equally and properly between the lands 2, which precede the land 2a at the farthest rear end. It is, therefore, possible to prevent the generation of solder bridge between a plurality of electrodes 5 for multi-leg electronic components 4 which correspond to the proximity of the land 2 at the farthest rear end.

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 on which multi-legged electronic components such as ICs are mounted, and a method for soldering the same.

0002

2. Description of the Related Art Electrodes of multi-legged electronic components are soldered to a plurality of lands provided on a wiring board device by various methods. In the soldering method using the solder dip method, a large amount of solder adheres between lands adjacent to the rearmost land with respect to the solder dip direction (substrate traveling direction). In other words, near the land that is the last to leave the solder spout, there is no land that follows, so the solder does not move backwards.
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 a multi-legged electronic component are short-circuited by solder, is likely to be formed. Therefore,
Various methods have been proposed to prevent the formation of solder bridges.

FIG. 4 shows an example of a conventional wiring board device S, which is constructed as follows. Reference numeral 1 designates a wiring board, and a multi-legged electronic component such as an SOP (Small Outline) is mounted on this mounting surface 1a (upper surface in FIG. 4).
Package) IC4 is implemented. On the mounting surface 1a of the wiring board 1, a plurality of lands 2 made of conductive foil are provided close to each other at positions corresponding to the plurality of electrodes 5 led out from both sides along the longitudinal direction of the SOPIC 4, respectively.

[0004] Also, a land for removing unnecessary solder (
3 (hereinafter referred to as a "discarded land") is provided. This waste land 3 is also formed on the same plane as the other lands 2 (2a), and is integrally connected to the rearmost land 2a in a U-shape.

Now, 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 spouting part
Insert each electrode 5 of the SOPIC 4 so that the electrodes a are facing each other.
solder to the corresponding land 2 (2a).

In such a conventional wiring board device S, the rearmost land 2a that finally enters the solder spouting portion
Since the waste land 3 is provided behind the
Solder is drawn to the part. Therefore, the solder is evenly and appropriately applied between the lands 2 (2a) preceding the discarded land 3, so that the plurality of electrodes 5 of the SOPIC 4 corresponding to the vicinity of the rearmost land 2a are soldered and short-circuited. This makes it difficult for solder bridges to occur.

[0007]

[Problem to be solved by the invention] However, the abandoned land 3
Since the surface of is lower than the lead-out part (base part) 5a of the electrode 5 of the SOPIC 4 from the package, the waste land 3 separates from the solder spouting part X earlier than the base part 5a of the electrode 5 corresponding to the rearmost land 2a. In other words, the solder adhering to the base 5a of the electrode 5 corresponding to the rearmost land 2a is not removed to the land 3, and the amount of solder adhering near the electrode 5 increases. Therefore, it has been difficult to completely prevent the occurrence of solder bridges. FIG. 6 shows an example where solder bridging occurs.

Therefore, it is an object of the present invention to effectively prevent the occurrence of solder bridges.

[0009]

[Means for Solving the Problems] A wiring board device according to a first aspect of the present invention provides a wiring board with a plurality of lands for connecting electrodes of a multi-legged electronic component in succession, and connects the plurality of lands to a wiring board. An extension member having a solder attachment surface higher than the land surface is provided on the connecting extension line.

[0010] The soldering method according to the second invention mounts the multi-legged electronic component corresponding to the plurality of lands of the wiring board device according to the first invention, and mounts the multi-legged electronic component on the side opposite to the side on which the spreading member is provided. The multi-legged electronic component is soldered by entering the solder spouting portion from the side in the direction of the extension line at a predetermined angle of inclination.

[0011]

[Operation] In the first invention, since the spreading member 6 having the solder attachment surface 6a higher than the land surface is provided behind the rearmost land 2a, the spreading member 6 corresponds to the rearmost land 2a. The molten solder leaves the molten solder (for example, the solder spouting part X in the flow method among the dip methods) later than the electrode 5. In other words, since the solder adhesion surface 6a of the spreading member 6 is dipped to the end, the solder is pulled up to the solder adhesion surface 6a. Therefore, solder is applied uniformly and in an appropriate amount between the lands 2 preceding the rearmost land 2a. Therefore, generation of solder bridges between the plurality of electrodes 5 of the multi-legged electronic component 4 corresponding to the vicinity of the rearmost land 2a is prevented.

In the second invention, since the wiring board device S according to the first invention is inserted into the solder spouting portion X at a predetermined inclination angle θ, the spreading member 6 It is slower and easier to separate from the solder spouting part X. Therefore, solder bridging between the plurality of electrodes 5 of the multi-legged electronic component 4 corresponding to the vicinity of the rearmost land 2a is more reliably prevented.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. In FIG. 1, parts corresponding to those in FIG. 4 are designated by the same reference numerals, and detailed explanation thereof will be omitted. As shown in FIG. 1, the rearmost land 2a is formed to be long and extended rearward by a predetermined distance. Continuing from the rear end of this rearmost land 2a, a spreading member 6 having a solder attachment surface 6a higher than the land surface is provided. As shown in FIG. 1, this extension member 6 has a substantially rectangular ring shape, and may be mounted at the same time as the SOPIC 4 is mounted. The height T of the extending member 6 is set such that the base portion 5a of the electrode 5 corresponding to the rearmost land 2a separates from the solder spouting portion X earlier than the extending member 6.

As shown in FIG. 2, the plunge angle of the wiring board 1 into the solder spouting part X is θ, the height of the base 5a of the electrode 5 corresponding to the land 2 (2a) is H, and the rearmost land 2a is If the distance to the spreading member 6 is L, the height T of the spreading member 6 is
For example, it is set to satisfy equation (1).

T≧H−Ltanθ (1) As is clear from equation (1), L can be made smaller by setting T larger. This example is configured as described above, and the rest is configured similarly to the example of FIG. 4.

In this example, the wiring board 1 includes a SOPIC
4, first mount the SOPIC 4 at an appropriate position on the mounting surface 1a. Next, as shown in FIG. 2, the mounting surface 1a is projected at a predetermined inclination angle θ to face the solder spouting part X, and each electrode 5 of the SOPIC 4 is soldered to the corresponding land 2 (2a). do.

In this example, a spreading member 6 is provided which has a solder adhesion surface 6a higher than the land surface behind the rearmost land 2a.
, the spreading member 6 leaves the solder spouting portion X later than the base portion 5a of the electrode 5 corresponding to the rearmost land 2a. In other words, since the solder adhesion surface 6a of the spreading member 6 is dipped to the end, the solder is drawn to the part of the solder adhesion surface 6a, and the last part between the electrode 5 and the spreading member 6 corresponding to the rearmost land 2a is Solder is applied to the entire end land 2a (see FIG. 3). Therefore, solder is applied uniformly and in an appropriate amount between the lands 2 preceding the rearmost land 2a. Therefore, according to this example, the occurrence of solder bridges between the plurality of electrodes 5 of the SOPIC 4 corresponding to the vicinity of the rearmost land 2a can be effectively prevented.

Furthermore, in this example, since the wiring board device S is plunged into the solder spouting portion X at a predetermined inclination angle θ, the spreading member 6 is closer to the base portion 5a of the electrode 5 corresponding to the rearmost land 2a. It becomes easier to separate from the solder spouting part X later. Therefore, according to this example, solder bridging between the plurality of electrodes 5 of the SOPIC 4 corresponding to the vicinity of the rearmost land 2a can be more reliably prevented.

Regarding the height T of the spreading member 6, the plunge angle θ with respect to the solder spouting portion X is 6°, and the base 5 of the electrode 5 is
According to the experimental results in which the height H of a is set in advance to 1.5 mm and the distance L between the rearmost land 2a and the spreading member 6 is 2 mm, when the height T of the spreading member 6 is 0.4 mm, 5 times. As a result of the rush, solder bridges were created in seven locations. When the height T of the spreading member 6 was 1.25 mm, no solder bridge was formed even after 12 insertions.

Note that the extension member 6 of the above embodiment may be a component related to an IC. In short, as long as the spreading member 6 has a solder attachment surface 6a higher than the land surface, it can be similarly applied. Furthermore, the multi-legged electronic component is an example of SOPIC4, but this invention is a QFP (Quad Flat
It can also be applied when mounting multi-legged electronic components such as package) ICs.

[0021]

According to the first aspect of the invention, since the spreading member having the solder adhesion surface higher than the land surface is provided behind the rearmost land, the solder adhesion surface of the spreading member is dipped to the end, thereby preventing solder adhesion. By drawing the solder to the surface, it is possible to effectively prevent the occurrence of solder bridges between the plurality of electrodes of the multi-legged electronic component corresponding to the vicinity of the rearmost land.

According to the second invention, since the wiring board device according to the first invention is inserted into the solder spouting part at a predetermined angle of inclination, the spreading member spreads the solder more slowly than the electrode corresponding to the rearmost land. It becomes easier to separate from the spouting part, and it is possible to more reliably prevent solder bridging between the plurality of electrodes of the multi-legged electronic component corresponding to the vicinity of the rearmost land.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an embodiment.

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

FIG. 3 is a diagram showing the state after soldering of the embodiment.

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

FIG. 5 is a diagram showing a state during soldering in a conventional example.

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

[Explanation of symbols]

1　Wiring board 2 Land 2a End land 4 SOPIC 5 Electrode 5a Base 6. Spreading member 6a　Solder adhesion surface S　Wiring board device X Solder spouting part θ　　Inclination angle

Claims (2)

[Claims] 1. A spreading member, wherein a plurality of lands for connecting electrodes of a multi-legged electronic component are successively provided on a wiring board, and a solder adhesion surface higher than the land surface is provided on an extension line connecting the plurality of lands. A wiring board device comprising: 2. A multi-legged electronic component is mounted corresponding to the plurality of lands of the wiring board device according to claim 1, and a solder spouting portion is mounted in the direction of the extension line from the side opposite to the side where the spreading member is provided. A method of soldering a wiring board device in which the multi-legged electronic component is soldered by protruding into the circuit board at a predetermined angle of inclination.