JPH08264935A - Method of soldering part to printed board - Google Patents

Abstract

PURPOSE: To provide the soldering method with which an electronic part can be closely soldered to a printed board. CONSTITUTION: An electronic part 10 is temporally fixed to a temporal fixing board 14 using an adhesive agent, and the substrate 14 and a printed board 12 are bonded by bringing the electric part 10 into contact with the printed board 12. Solder pouring holes 30 are provided on the substrate 14, fused solder is poured through the holes 30 into the gap formed by pinching the electric part with the substrate 14 and the printed board 12, and the electronic part 10 is soldered to the printed substrate 12. By separating the printed board 12 and the substrate 14 after soldering, the temporally fixed state of the electric part 10 and the substrate 14 is removed. Accordingly, the generation of a gap, which is caused by an adhesive agent, etc., between the printed board 12 and the electric part 10, can be prevented and the intrusion of a foreign matter can also be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for soldering various parts such as electronic parts mounted on a printed board to the printed board.

[0002]

2. Description of the Related Art Conventionally, in a process of soldering an electronic component to a printed circuit board, the printed circuit board 12 is brought close to a solder bath 42 from above as shown in FIG. Then, a so-called flow soldering method of soldering a desired portion is used.

When performing such flow soldering, the electronic component 10 is printed in advance with an adhesive 40 as shown in FIG. 5A so that the electronic component 10 does not drop during the soldering process. It was necessary to temporarily fix the substrate 12.

Therefore, the printed circuit board 1 is bonded with the adhesive 40.
In a state in which the electronic component 10 is temporarily fixed to 2, the lower surface, that is, the flow surface side of the printed board 12 is brought close to the molten solder 24 and soldered as shown in FIG. 12 and the electronic component 10 were electrically and mechanically connected by the solder 26.

[0005]

However, as shown in FIG.
As shown in (c), the printed circuit board 12 and the electronic component 10
The adhesive 40 is interposed between the printed circuit board 1 and
If there is a portion where the adhesive 40 does not exist between the electronic component 10 and the electronic component 10, a void 44 will be formed there. Then, during the soldering process, there is a possibility that flux residue or solder balls may get into the voids 44, and if they get in, they cannot be removed by washing, causing migration and the like. was there.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a method capable of closely soldering electronic components to a printed circuit board.

[0007]

In order to achieve the above object, a method of soldering a component to a printed circuit board according to the present invention comprises a step of temporarily fixing a component to a temporary fixing substrate with a temporary fixing material, A step of bringing the temporarily fixed component into contact with a printed circuit board for mounting the solder, and pouring solder into a gap formed by sandwiching the component between the temporary fixed circuit board and the printed circuit board so that the component is The method is characterized by including a step of soldering to a printed circuit board, a step of releasing the temporarily fixed component, and a step of releasing the temporarily fixed state of the temporary fixed board.

[0008]

According to the soldering method of the present invention, the component is temporarily fixed to the temporary fixed substrate instead of the printed substrate, and the solder is poured into the gap formed by sandwiching the component between the temporary fixed substrate and the printed substrate. Therefore, it is not necessary to provide a temporary fixing means or the like between the printed circuit board and the component, and a gap due to the temporary fixing means or the like does not occur between the printed circuit board and the component. Therefore, according to the soldering method of the present invention, it is possible to prevent the problem that migration or the like occurs due to the entry of foreign matter into the space between the printed board and the component as in the conventional case.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of soldering an electronic component to a printed board according to an embodiment of the present invention will be described below with reference to the drawings.

Embodiment 1. In the present embodiment, as shown in FIG. 1, the temporary fixing substrate 14 for temporarily fixing the electronic component 10 such as various electric elements is selectively soldered to a portion corresponding to the soldering portion 28 of the electronic component 10. A casting hole 30 is formed. The temporary fixed substrate 14 is formed by using a fluorine-based resin or the like having poor wettability with solder.

On the other hand, as shown in FIG. 3, the printed circuit board 12 is patterned with a copper foil 16 having wiring in an arbitrary shape, and the soldered portion 1 is formed on a part of the surface of the copper foil 16.
8 are formed. Further, a photoresist 20, which also functions as an adhesive, is filled between the copper foils 16 for smoothing the surface of the printed circuit board.

Next, the soldering method of this embodiment will be described.

First, the temporary fixing substrate 14 having the above structure.
The electronic component 10 is temporarily fixed to the surface of the electronic component 10 by using, for example, a silicon adhesive as a temporary fixing means. The temporary fixing of the electronic component 10 to the temporary fixing substrate 14 is not limited to the adhesive, but a dent is formed in the electronic component installing portion of the temporary fixing substrate 14, and the electronic component 10 is fitted into the concave electronic component installing portion. The structure may be temporarily fixed with.

Then, after the electronic component 10 is temporarily fixed to the temporary fixing substrate 14, the printed circuit board 12 is brought into contact with the electronic component 10 to fasten the temporary fixing substrate 14 and the above-mentioned printed circuit board 12 to each other. The electronic component 10 is brought into close contact with the photoresist 20 portion of 12.

After fastening the substrates 12 and 14, the printed circuit board 1
The fastened substrates 12 and 14 are brought close to the solder bath 42 with 2 being the upper side and the temporarily fixed substrate 14 being the lower side. As a result, the molten solder 24 flows into the gap between the printed circuit board 12 and the temporary fixed board 14 from the solder pouring hole 30 of the temporary fixed board 14, and the soldered portion 28 of the electronic component 10 and the soldered portion of the printed circuit board 12 of FIG. And 18 are selectively soldered.

After soldering is completed, the temporary fixed substrate 14 and the printed circuit board 12 are separated from each other, so that the temporary fixed state between the temporary fixed substrate 14 and the electronic component 10 is released, and the printed circuit board 1 is released.
A printed circuit board 12 to which the electronic component 10 is soldered is obtained without a gap with respect to 2.

In this embodiment, the temporary fixed substrate 14
Is not limited to the structure shown in FIG. 1, but may be formed with innumerable solder pouring holes 32 as shown in FIG. If innumerable solder casting holes 32 are formed in the temporary fixing substrate 14 as shown in FIG. 2, it is necessary to prepare the temporary fixing substrate 14 having different hole positions and sizes according to the size of the electronic component 10 to be temporarily fixed. There is an effect that there is no.

As described above, in this embodiment, the electronic component 10 can be soldered in a state in which the printed circuit board 12 is in close contact with the printed circuit board 12 by using the temporary fixed circuit board 14 in which the solder casting holes 30 and 32 are formed. Therefore, it is possible to prevent foreign matter such as solder balls from entering the gap between the printed circuit board 12 and the electronic component 10. Further, there is an effect that the flow soldering process can be performed by using the same soldering mechanism as the conventional one.

Example 2. The second embodiment is characterized in that an electronic component is soldered to a printed board by using a temporary fixed board having no solder pouring hole.

This embodiment will be described below with reference to FIGS. 3 and 4.

As the printed board 12, a board having a structure as shown in FIG. 3 is used as in the first embodiment. On the other hand, the temporary fixing substrate 34 shown in FIGS. 3 and 4 is made of a material such as a fluororesin having poor wettability with solder as in the first embodiment, but the temporary fixing substrate 34 is substantially flat. However, the solder pouring hole is not formed.

First, the electronic component 10 is temporarily fixed to the surface of the temporary fixing substrate 34 by using, for example, a silicon adhesive 22 as a temporary fixing means.

Next, the printed board 12 and the temporary fixed board 34 are fastened so that the printed board 12 and the electronic component 10 are in close contact with each other, and the fastened board is erected as shown in FIG. 4 (a). The electronic component 10 is held between the two substrates 12 and 34 by the adhesive force of the adhesive and an appropriate fastening pressure between the temporary fixing substrate 34 and the printed circuit board 12, and when the substrates 12 and 34 are fastened. The electronic component 10 is prevented from dropping and the contact position between the electronic component 10 and the printed circuit board 12 being displaced.

After fastening, both boards 12 and 34 are preheated to about 80 deg, and in this state, the flux 36 is poured from the gap between the printed board 12 and the temporary fixed board 34 as shown in FIG. 4B.

Subsequently, as shown in FIG. 4 (c), the molten solder 24 is caused to flow out from the lower portion of the solder bath 38 so that the substrates 12, 3 are formed.
Pour into the upper gap between the four. As a result, the soldering portion 18 of the printed board 12 and the soldering portion (not shown) of the electronic component 10 are electrically and mechanically soldered.

Here, as shown in FIG. 4 (d), the solder bath 38 is provided with heating means 38a on the inside thereof and heat insulating means 38b on the outside thereof. The molten solder 24 can flow out.
As described above, in this embodiment, by supplying the molten solder 24 from the lower portion of the solder bath 38, the surface area of the solder exposed to the outside air can be reduced, and the solder is soldered in a state in which the oxidation of the solder is suppressed to the minimum. Is possible.

After the above steps are completed, when the printed board 12 and the temporary fixed board 34 are separated, the electronic parts 10 and the temporary fixed board 34 are released from the temporarily fixed state, and the electronic parts 10 and The printed circuit board 12 to which the component 10 is soldered is obtained.

As described above, in this embodiment, the electronic component 10 can be soldered in a state in which the electronic component 10 is in close contact with the printed circuit board 12 without the need for a specially shaped substrate as the temporary fixing substrate. Printed circuit board 12 and electronic component 10
It is possible to prevent a foreign matter such as a solder ball from entering a space between and to cause migration or the like.

[0029]

According to the soldering method of the present invention, the component is temporarily fixed to the temporary fixed substrate instead of the printed substrate, and the solder is poured into the gap formed by sandwiching the component between the temporary fixed substrate and the printed substrate. . Therefore, it is not necessary to provide temporary fixing means between the printed circuit board and the component, and the component can be closely attached to the printed circuit board and soldered. As a result, no gap is generated between the printed circuit board and the component due to the temporary fixing means or the like, and the problem of foreign matter entering between the printed circuit board and the component unlike the conventional soldering method is prevented. be able to.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a method for soldering an electronic component to a printed board according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a temporary fixing substrate having a structure different from that of FIG.

FIG. 3 is a diagram showing a state in which a temporary fixed substrate and a printed circuit board are fastened together.

FIG. 4 is a diagram showing a method for soldering an electronic component to a printed board according to a second embodiment of the present invention.

FIG. 5 is a diagram showing a conventional method for soldering an electronic component to a printed circuit board.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 electronic parts, 12 printed circuit boards, 14, 34 temporary fixed boards, 30, 32 solder pouring holes, 16 copper foil, 2
2 adhesive, 24 molten solder, 36 flux, 38
Solder bath.

Claims (1)

[Claims] 1. A step of temporarily fixing a component to a temporary fixing substrate with a temporary fixing material; a step of bringing the temporarily fixed component into contact with a printed circuit board on which the component is mounted; A step of pouring solder into a gap formed by sandwiching the component with the printed circuit board, and soldering the component to the printed circuit board, a temporarily fixed state of the temporarily fixed component and the temporary fixed substrate. A method of soldering a component to a printed circuit board, the method including: a step of releasing.