JPH0739035B2 - Flux application method and device - Google Patents

Description

DETAILED DESCRIPTION [Overview] A method and apparatus for applying flux to external connection terminals of electronic devices such as ICs, in which flux is uniformly and reliably applied to a plurality of external connection terminals to improve productivity. A method for applying a flux to an external connection terminal of an electronic device having a plurality of external connection terminals protruding on one side for the purpose of After mounting the electronic device so that the external connection terminals face the sponge-like elastic body on the electronic device mounting surface of the electronic device mounting base that can move up and down with respect to the elastic body,
An external connection terminal of the electronic device is brought into contact with the sponge-like elastic body to which the flux has been supplied by pressing the electronic device and moving the electronic device mounting base that descends together with the electronic device.

A flux applicator for applying flux to the external connection terminals of an electronic device having a plurality of external connection terminals protruding on one side, wherein the electronic device is mounted in an area excluding the external connection terminals. With a face,
Also, an electronic device mounting base having a means for descending only when the electronic device mounting surface is pressed down, and the electronic device surrounding the electronic device mounting base so that the electronic device mounting surface is exposed. A flux applicator having means for restricting the amount of vertical movement of the mounting table and having a sponge-like elastic body mounted on the upper surface thereof so as to cover at least the region where the external connection terminals of the electronic device are present, and the flux coating table. An electronic device mounted on the electronic device mounting surface so that the external connection terminal faces the sponge-like elastic body, and the external connection terminal has the sponge-like elasticity. Means for supplying the flux in the dipping tank to the sponge-like elastic body while pressing down to the position where it comes into contact with the body surface is provided. To configure.

[Industrial application field]

The present invention relates to a flux coating process for external connection terminals of electronic devices such as ICs, and particularly to a flux coating method and apparatus for uniformly and reliably coating flux on a plurality of external connection terminals to improve productivity. Regarding

The number of external connection terminals is increasing rapidly with the recent increase in the integration density of electronic devices such as ICs. Especially, the soldering process for temporarily soldering such electronic devices to a circuit board (hereinafter referred to as tacking). However, since many external connection terminals must be surely connected, how to apply flux to each external connection terminal uniformly and surely becomes a problem.

[Conventional technology]

In order to mount electronic devices such as ICs on a circuit board or tack them, flux is usually applied to the connection parts to improve solderability.

One of the means for applying the flux in this case is a method of applying by immersing only a predetermined portion of the external connection terminal of the electronic device in an immersion tank filled with the flux solution, but the flux solution is volatile. Therefore, it is difficult to keep the liquid level constant at all times, and as a result, there is a drawback that a constant amount of flux cannot always be uniformly applied to a predetermined portion of the external connection terminal of the electronic device with good reproducibility. is there.

Therefore, in the case of an electronic device having a particularly large number of external connection terminals, a method of applying flux to a connection pattern portion of the circuit board with the electronic device is often used.

FIG. 3 is a diagram illustrating an example of a conventional flux applying method.

In FIG. 3, a connection electrode 1a is patterned on the surface of a partially enlarged circuit board 1 at a position corresponding to each external connection terminal 2a of the electronic device 2 such as an IC to be tacked.

Therefore, for example, a spray gun 3 as shown in the drawing sprays a flux liquid onto the area a where the connection patterns 1a are formed to apply the flux to each connection pattern 1a.

After that, each external connection terminal 2a of the semiconductor device 2 and the corresponding connection pattern 1a on the circuit board 1 are matched by a visual camera or the like to be aligned and tacked.

In this case, there is a merit that the flux can be efficiently applied without requiring special equipment.

However, since it is applied by spraying the flux liquid on the circuit board, the connection pattern 1a becomes difficult to see at a place where the flux liquid is dripping or sprayed in a large amount at the end of the connection pattern 1a, for example. It may disappear.

Further, particularly in a highly integrated LSI or the like, the pitch p between the external connection terminals 2a and thus between the connection patterns 1a on the circuit board 1 is increased.
Therefore, if the connection pattern 1a becomes difficult to see as described above, the matching accuracy between the external connection terminal 2a and the connection pattern 1a at the time of tacking decreases.

Therefore, there is a drawback that it takes a lot of time for matching at the time of tacking and there is a risk that a connection error such as conduction between adjacent terminals occurs.

[Problems to be Solved by the Invention]

The conventional flux coating method makes it difficult to see each connection pattern on the circuit board, which reduces the matching accuracy between the external connection terminal and the connection pattern when tacking, and it takes a lot of time for tacking to improve productivity. There was a problem that it could not be expected, and there was a problem that there was a high risk of connection mistakes.

[Means for Solving the Problems]

The above-mentioned problem is a method of applying a flux to an external connection terminal of an electronic device having a plurality of external connection terminals protruding on one side, and a sponge-like elastic body having a size that covers an existing region of the external connection terminal. After mounting the electronic device on the electronic device mounting surface of the electronic device mounting base that can move up and down so that the external connection terminals face the sponge-like elastic body, press the electronic device, This is solved by a flux applying method of bringing the external connection terminals of the electronic device into contact with the sponge-like elastic body to which the flux has been supplied by the movement of the descending electronic device mounting table.

A flux applicator for applying a flux to the external connection terminals of an electronic device having a plurality of external connection terminals protruding to one side, wherein the electronic device is mounted in an area excluding the external connection terminals. With a face,
Also, an electronic device mounting base having a means for descending only when the electronic device mounting surface is pressed down, and the electronic device surrounding the electronic device mounting base so that the electronic device mounting surface is exposed. A flux applicator having means for restricting the amount of vertical movement of the mounting table and having a sponge-like elastic body mounted on the upper surface thereof so as to cover at least the area where the external connection terminals of the electronic device are present, and the flux. An electronic device is mounted on the electronic device mounting surface so that the external connection terminal faces the sponge-like elastic body, and the external connection terminal has the sponge-like elasticity. Means for supplying the flux in the dipping tank to the sponge-like elastic body while pressing down to the position where it comes into contact with the surface of the body It is solved by a coating apparatus of the flux being configured.

[Work]

When each external connection terminal of the electronic device is brought into contact with the surface of a sponge-like elastic body (hereinafter simply referred to as sponge) having a constant liquid content, a constant amount of flux can be uniformly applied to the external connection terminal.

In the present invention, when the electronic device is mounted on a jig so that the connection portion of the external connection terminal faces the sponge surface, and the electronic device is lowered until the connection portion of the external connection terminal contacts the sponge surface. The coating device is configured so that a constant amount of the flux liquid is supplied to the sponge.

Therefore, by using the coating apparatus, the flux can be uniformly and surely applied to the external connection terminals efficiently, and the connection terminals on the circuit board will not be difficult to see even in the subsequent tacking step, and efficient tacking will be achieved. You can do the work.

〔Example〕

FIG. 1 is a diagram for explaining a coating method according to the present invention and a configuration example of the apparatus, (A) shows a state before coating, and (B).
[Fig. 3] is a diagram showing a state during application.

Further, FIG. 2 is a diagram showing another configuration example.

Note that the configuration of the coating device will be described first in order to facilitate understanding.

In FIG. 1 (A), the coating device 11 has a cylindrical bottomed flux liquid immersion tank 12 and a cylindrical cylindrical section whose cross-section along the central axis fixed to the central portion of the immersion tank 12 is almost portal-shaped. A flux coating table 13 having a plurality of through holes 13a formed in the vicinity of a lower end portion thereof, and a vertical movement of a predetermined distance h with respect to the flux coating table 13 through the central through hole 13a of the flux coating table 13. The electronic device mounting base 14 having a thick collar 14a and a sponge 15 having a ring shape in a plan view, which is positioned and mounted on the upper surface of the flux coating base 13, are configured as main components.

The upper surface 15a of the sponge 15 in this case is the electronic device mounting surface 14 of the electronic device mounting base 14 located at the top.
The distance h ′ between the external connection terminal of the device and the flux-coated surface when the required electronic device is mounted on b is set to a position equal to the moving distance h of the mounting base 14.

Further, the electronic device mounting base 14 has one end inserted into a plurality of (two in the figure) holes 14d circularly arranged on the lower surface 14c of the thick-walled collar 14a, and the other end corresponds to the hole 14d on the bottom surface of the immersion tank 12. It is positioned by a stud 12a attached at a position to be constantly pushed upward by a compression spring 16 attached to the dipping tank 12, and a lower surface 14 is provided along the central axis thereof.
Hole 14 with a depth from c to the vicinity of electronic device mounting surface 14b
A plurality of (for example, four) branch holes 14f are formed from the upper end of the hole 14e and are evenly branched from the upper end of the hole 14e so as to penetrate to the peripheral surface thereof.

In this case, each branch hole 14f corresponds to the electronic device mounting base 14f.
The upper surface 15 of the sponge 15 when is located at the top
It turns to face a.

In the coating apparatus 11 having such a structure, when the flux liquid 17 is poured into the dipping tank 12, the flux liquid 17 is supplied from the through hole 13a near the lower end of the flux coating base 13 to the flux coating base 1
Since it enters the inside of 3, the inside is filled with the flux liquid 17.

Therefore, the electronic device 2 described with reference to FIG. 3 is mounted on the electronic device mounting surface 14b of the electronic device mounting base 14 such that the external connection terminals 2a face the lower side, that is, the upper surface 15a of the sponge 15, and the electronic device is directly mounted. When 2 is pushed down as indicated by arrow A, the electronic device mounting base 14 is lowered together with the electronic device 2 against the compression spring 16, so that the flux liquid 17 on the lower surface side of the electronic device mounting base 14 is moved as shown by arrow B. After entering the hole 14e, a plurality of branch holes 14 are passed through the hole 14e.
It is jetted from f to the upper surface 15a of the sponge 15 as shown by an arrow C and absorbed by the sponge 15.

The flux liquid absorbed by the sponge 15 in this case
The quantity of 17 is always constant.

Then, as shown in (B), when the lower surface 14c of the electronic device mounting base 14 comes into contact with the bottom surface of the immersion tank 12, the mounting base 14 stops descending. At this time, the external connection terminal of the electronic device 2 is connected. Since 2a contacts the upper surface 15a of the sponge 15, the flux 17 can be applied to the external connection terminals 2a reliably and uniformly.

When the electronic device 2 is separated from the electronic device mounting base 14, the electronic device mounting base 14 is raised by the compression spring 16 and returns to the initial state (A).

The flux coating operation can be continued by following the same procedure.

Particularly when such a coating device is used, the flux liquid 17 is supplied to the sponge 15 every time the electronic device 2 is pressed down, that is, the electronic device mounting base 14 is lowered, so that there is little variation in the coating state due to repetitive work and there is always Flux application work in the same state can be continuously performed with good reproducibility.

Further, in the coating apparatus having such a configuration, the flux liquid 17 is applied to the sponge 15 regardless of the amount of the flux liquid 17 in the dipping tank 12.
Is supplied, there is an advantage that the flux application work can be continued in a stable state for a long period of time.

In FIG. 2 showing another example, the coating apparatus 21 has the same size as the flux liquid immersion tank 12 described in FIG. 1 and the flux coating table 13 of FIG. 1 fixed to the central portion of the immersion tank 12. Of the flux coating table 22, an electronic device mounting table 23 that can penetrate the central through hole 22a of the flux coating table 22 and move up and down by a predetermined distance h with respect to the flux coating table 22, and the upper surface of the flux coating table 22. The main component is the sponge 15 described in FIG.

In this case, when the upper surface 15a of the sponge 15 is located at the uppermost position, the distance h ′ between the upper surface 15a of the sponge 15 and the flux application surface of the external connection terminal of the electronic device mounted on the electronic device mounting base 23 is the mounting base. It is similar to FIG. 1 in that it is equal to the moving distance h of 23.

Further, in particular, in this case, the flux coating table 22 is provided with a plurality of circular shapes parallel to the central axis in the portion of the step portion 22c protruding inward together with the through hole 22b provided in the vicinity of the lower end portion thereof as in FIG. A through hole 22d is bored.

Further, the electronic device mounting base 23 having the same size as the electronic device mounting base 14 described in FIG. 1 has a plurality of (two in the figure) holes 2 circularly arranged on the lower surface 23a thereof as in the case of FIG.
3b and the compression spring 16 positioned by the bottom stud 12a of the immersion tank 12 always pushes upward.

In the coating apparatus 21, when the flux liquid 17 is poured into the dipping tank 12, the inside of the flux coating table 22 is filled with the flux liquid 17 as in FIG.

Therefore, the electronic device 2 is mounted on the electronic device mounting surface 23b of the electronic device mounting base 23 so that the external connection terminals 2a thereof face the upper surface 15a of the sponge 15, and the electronic device 2 is pressed as indicated by arrow A '. Then, the electronic device mounting base 23 descends against the compression spring 16, so that the flux liquid 17 on the lower surface side of the electronic device mounting base 23 penetrates the through hole 22d.
Is raised as shown by arrow B'and absorbed by the sponge 15 located above it.

Then, when the electronic device 2 is further pressed, the external connection terminals 2a of the electronic device 2 come into contact with the sponge 15 at the position where the electronic device mounting base 23 is stopped, and the electronic device 2 is separated from the electronic device mounting base 23. And the mounting base 23 is raised by the compression spring 16 and returns to the initial state.
It is similar to the case of the figure.

When using the coating device 21, the electronic device 2
Since the flux liquid 17 is supplied to the sponge 15 every time when the electronic device mounting base 23 is pushed down, that is, the same effect as in the case of FIG. There is an advantage that it can be applied to a wider range of flux than in the case of FIG.

〔The invention's effect〕

As described above, according to the present invention, it is possible to provide a flux applying method and apparatus for uniformly and reliably applying flux to a plurality of external connection terminals to improve productivity.

If the electronic device is particularly sensitive to static electricity, the same effect can be obtained by replacing the sponge-like elastic body with a conductive sponge-like elastic body containing, for example, carbon.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a coating method according to the present invention and a configuration example of an apparatus thereof, FIG. 2 is a diagram illustrating another configuration example, and FIG. 3 is a diagram illustrating an example of a conventional flux coating method. is there. In the figure, 2 is an electronic device, 2a is an external connection terminal, 11,21 is a coating device, 12 is a dipping tank, 12a is a stud, 13,22 is a flux coating table, 13a, 22a, 22b and 22d are through holes, 14 , 23 is an electronic device mounting base, 14a is a thick tsuba, 14b, 23b is an electronic device mounting surface, 14c, 23a is a lower surface, 14d, 14e, 23b are holes, 14f is a branch hole, 15 is a sponge, 15a is an upper surface, 16 is a compression spring, 17 is a flux liquid, and 22c is a step.

Claims (2)

[Claims] 1. A method for applying a flux to an external connection terminal of an electronic device comprising a plurality of external connection terminals protruding to a plane side, the sponge having a size to cover a region where the external connection terminal (2a) exists. The electronic device (2) on the electronic device mounting surface (14b) of the electronic device mounting base (14) that can move up and down with respect to the elastic body so that the external connection terminal (2a) faces the sponge elastic body. After mounting the electronic device (2), the electronic device mounting base (14) that moves down together with the electronic device (2) moves to the sponge-like elastic body to which the flux (17) is supplied. A method for applying a flux, which comprises contacting an external connection terminal (2a) of a device (2). 2. A flux applicator for applying a flux to an external connection terminal of an electronic device comprising a plurality of external connection terminals protruding on one side, wherein the electronic device (2) is connected to the external connection terminal (2a). A vertically movable electronic device mounting base (14) having an electronic device mounting surface (14b) to be mounted in a region other than the above and equipped with means for descending only when the electronic device mounting surface (14b) is depressed.
And a means for surrounding the electronic device mounting base (14) so as to expose the electronic device mounting surface (14b) and restricting the vertical movement amount of the electronic device mounting base (14), and at the upper surface thereof. A flux applicator table (13) having a sponge-like elastic body large enough to cover at least the area where the external connection terminals (2a) of the electronic device (2) are present.
And a flux dipping bath (12) accommodating the flux coating table (13), and the electronic device mounting surface (14b) so that the external connection terminal (2a) faces the sponge-like elastic body. ), The flux (17) in the dip tank (12) is applied to the sponge while the external connection terminal (2a) of the electronic device (2) is pressed to a position where the external connection terminal (2a) contacts the surface of the sponge-like elastic body. A flux applicator characterized in that the flux applicator is configured so as to be supplied to the elastic body.