JPH0666542B2 - Adhesion method for circuit board mounted parts - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for adhering and fixing electronic components mounted on a circuit board with an adhesive.

[Prior Art] A method of mounting the electronic component 2 on the circuit board 1 will be described with reference to FIGS. 5 and 6. A so-called chip-type electronic component 2 having cap-shaped electrodes 2a, 2a at both ends is shown as the electronic component 2 shown in the figure, but the circuit board 1 faces the electrode 2a, 2a correspondingly. A pair of soldering electrodes 4 and 4 are provided. The electronic component 2 is
The soldering electrodes 4 and 4 are mounted, and the electrodes 2a and 2a on both ends thereof are soldered to the soldering electrodes 4 and 4.

The soldering of the electrodes 2a, 2a is generally performed by a so-called flow soldering method, in which the circuit board 1 is turned upside down so that the electronic component 2 side faces down, and the circuit board 1 is immersed in flow soldering for soldering. Therefore, in order to prevent the electronic component 2 from falling off in the soldering process, the soldering electrode 2
With the adhesive 3 applied between a and 2a, the electronic component 2
Conventionally, soldering is performed in a state in which is bonded to the circuit board 1 in advance.

In this case, the application of the adhesive 3 is performed by a screen printing method or a pin transfer method, and FIGS. 5 and 6 show a case where the adhesive 3 is applied by the pin transfer method.

[Problems to be Solved by the Invention] As shown in FIG. 6, the adhesive 3 applied to the surface of the circuit board 1 by the pin transfer method has a so-called high central portion and a gradually lower peripheral portion. Presents Yamagata. On the other hand, the pin transfer device and the mounting device for the electronic component 2 have some errors, and as shown in FIGS. 5 and 6, the application position of the adhesive 3 and the electronic component 2 are different. The mounting position often shifts slightly.

When the positional deviation occurs in this way, the adhesive force of the electronic component 2 due to the adhesive 3 is biased to the side of the electronic component 2 and a sufficient adhesive force cannot be obtained. Problems such as falling off the substrate 1 may occur. Since both sides of the adhesive 3 are inclined as described above, the electronic component 2 is laterally displaced along this inclination, and the electronic component 2 is further moved from the center of the soldering electrodes 4 and 4. It may shift.

As measures against this, measures such as increasing the application amount of the adhesive 3 or applying the adhesive 3 for a long time along the gap between the soldering electrodes 4 and 4 have been tried. However, in the former case,
Since a part of the adhesive 3 is easily attached to the soldering electrodes 4 and 4, the soldering is hindered. In the latter case,
There are problems such as uneven coating of the adhesive 3 and insufficient height of the adhesive 3.

The present invention has been made in view of the conventional problems described above, and an object thereof is to provide an electronic component bonding method capable of securely fixing an electronic component to an accurate position.

[Means for Solving the Problem] That is, the object of the present invention is to apply an adhesive 13 for fixing a component between the opposing soldering electrodes 14, 14 of the circuit board 11 for the soldering. In the method of adhering the electronic component 12 mounted over the electrodes 14 and 14 to the circuit board 11 with the adhesive 13 and fixing the electronic component 12 between the electrodes 14 and 14 for soldering,
The adhesive 13 is transferred by the transfer pin 15 to a position slightly displaced from the center line a connecting the electrodes 14 and 14, and thereafter,
Similarly, the adhesive 13 'is transferred between the soldering electrodes 14 and 14 at a position slightly deviated to the side opposite to the adhesive 13 with respect to the center line a connecting the electrodes 14 and 14. 1
This is achieved by a circuit board mounting component bonding method characterized by transferring by 5 ', mounting the electronic component 12 between these adhesives 13 and 13', and bonding.

[Operation] By the method of the present invention, as shown in FIG.
The two adhesives 13 and 13 'applied to the above are mixed and integrated with each other at their overlapping portions, and as shown in FIG. 3, they are displaced from the center line a by b and b', respectively. , Will have a mountain shape with two peaks. Therefore, this b
By mounting the electronic component 12 in the range of + b ', the adhesives 13 and 13' are adhered from both sides of the electronic component 12 substantially evenly. Also, the central portion near the center line a, that is, the adhesive 13 and the adhesive
Since the distance between 13 'and 13' is slightly lower, the electronic component 12 is adhered so that it is settled in this lower position.
The misalignment of is minimized.

When two transfer pins 15 and 15 'are arranged close to each other so that the adhesives 13 and 13' are simultaneously applied to two places,
Since the adhesive also adheres between the two transfer pins 15 and 15 'when immersed in the adhesive tank, the adhesive 13 and 13' applied to the circuit board 11 has a cross-sectional shape as shown in FIG. Therefore, the proper result cannot be obtained.

In particular, at the present time when electronic components are downsized and circuit boards are becoming finer and more densely mounted, it is necessary to apply two adhesives in close proximity to each other. However, if the two transfer pins 15 and 15 'are lined up close to each other as described above, when the transfer pins 15 and 15' are dipped in the adhesive and pulled up, an excess amount is generated due to the surface tension of the adhesive. The adhesive adheres like a bridge. Therefore, variations in the amount of adhesive applied and variations in the shape of the applied adhesive tend to occur.

[Embodiment] Next, an embodiment of the present invention will be described according to steps with reference to the drawings.

The transfer pin 15 is projected from a predetermined position of the transfer plates 16 and 16 '. In FIG. 4, two transfer plates 16 and 16' having the transfer pins 15 projected in the same pattern are prepared. Indicates the case.

Separately from this, an adhesive tank (not shown) filled with an adhesive in a dissolved state is prepared, and the transfer plates 16 and 16 'are moved so that the tips of the transfer pins 15 and 15' are adhesive. Immerse it in a bath and, as shown in FIG.
Attach. In this case, the tip shapes of the transfer pins 15 and 15 'are unified so that a constant amount of the adhesive 13, 13' is always applied to the tips of the transfer pins 15 and 15 ', and these are fixed to a certain depth. So far it is necessary to immerse it in the adhesive bath.

Next, the circuit board 11 is supplied below one of the transfer plates 16, and a predetermined position between the soldering electrodes 14 and 14 printed on the circuit board 11, that is, a center line connecting the soldering electrodes 14 and 14 The adhesive 13 is applied to a position displaced from the a by a slight distance b.

Next, the circuit board 11 is supplied below the other transfer plate 16 ′,
Therefore, a small distance b ′ from the predetermined position between the soldering electrodes 14, 14 or the center line a to the opposite side of the adhesive 13.
The adhesive 13 'is applied to the position shifted by just this amount.

Deviations b, b'of the adhesive 13, 13 'from the central axis a
Is b when the average radius of the applied adhesive 13 is r.
It is desirable that <r, b ′ <r.

After applying the adhesives 13 and 13 'in this way, the electrodes 14 and 1 are aimed at the center line a of the soldering electrodes 14 and 14.
Electronic component 12 is mounted over 4 '. That is, FIG.
As shown in FIG. 3, the electronic component 12 is placed on the circuit board 11 by an automatic mounting device (not shown), and the adhesive 1
The electronic component 12 is adhered and fixed to the circuit board 11 by 3, 13 '.

After that, the circuit board 11 is turned over and the surface on which the electronic component 12 is mounted is dipped in a flow solder bath (not shown) and soldered.

In the embodiment described above, the transfer of the adhesive is performed using the separate transfer plates 16 and 16 '. For example, two sets of transfer pins 15 and 15' are implanted in one transfer plate. Using the
Using these transfer pins 15 and 15 'of each set, the adhesive 1
It is of course possible to print 3, 13 '. Further, by using the transfer plate 16 provided with a set of transfer pins 15 and repeating the dipping of the transfer pins 15 in the adhesive tank and the transfer twice, the adhesives 13 and 13 at the two positions are similarly obtained. 'Can be printed sequentially. However, the latter method is
Since it is immersed twice in 15 adhesive tanks, it has the drawback of lengthening the process cycle.

[Effects of the Invention] As described above, according to the electronic component bonding method of the present invention, the electronic component 12 can be accurately bonded and fixed to a predetermined position between the soldering electrodes 14, 14 and is always stable. Adhesive strength can be reproduced. Therefore, there is an effect that the electronic component 12 can be accurately soldered.

[Brief description of drawings]

FIG. 1 is a plan view of an essential part of a circuit board to which an adhesive is applied according to an embodiment of the present invention, and FIG. 2 is a circuit board in which electronic parts are mounted on the adhesive according to the embodiment. FIG. 3 is a plan view of an essential part of FIG. 3, FIG. 4 is an enlarged sectional view taken along line AA of FIG. 2, FIG.
FIG. 5 is a side view of an essential part showing a step of pin-transferring the adhesive to the circuit board, FIG. 5 is a plan view of the essential part of the circuit board in a state where the adhesive is applied showing the conventional example, and FIG. It is a BB line expanded sectional view. 11 …… Circuit board, 12 …… Electronic parts, 13,13 ′ …… Adhesive, 14 …… Soldering electrode, 15,15 ′ …… Transfer pin

Claims (1)

[Claims] 1. A soldering electrode 14, which faces a circuit board 11,
A method of applying an adhesive 13 for fixing components between 14 and adhering the electronic component 12 mounted over the soldering electrodes 14, 14 to the circuit board 11 with the adhesive 13 and fixing the same. , Between the soldering electrodes 14, 14 and these electrodes 1
At a position slightly displaced from the center line a connecting 4 and 14, the adhesive 1
3 is transferred by the transfer pin 15, and thereafter, it is also between the soldering electrodes 14 and 14, and these electrodes 14 and 14 are
The adhesive 13 'is transferred by a transfer pin 15' to a position slightly displaced from the center line a connecting the two to the side opposite to the adhesive 13, and the electronic component 12 is placed between the adhesives 13 and 13 '. Equipped with
A method for adhering components mounted on a circuit board, which comprises adhering.