JP2674582B2 - Flux coating device and coating method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to application of flux when various electronic components are surface-mounted on a printed circuit board or the like and soldered and bonded, and particularly applied to highly integrated LSIs and the like requiring high quality. And a method for applying the same.

[0002]

2. Description of the Related Art Generally, in an LSI or the like having a high degree of integration that requires high quality of this kind, the pitch between leads is very small, and therefore the amount of solder supplied during soldering is limited. However, in order to obtain a sufficient bonding force, it has been required to apply an appropriate amount of flux. In the conventional flux application method, flux is applied to an electrode portion formed on the surface of a printed circuit board on which electronic components are mounted in advance, and then electronic components are mounted and soldering is performed. Further, as the method of applying the flux, brush application, brush application with a dispenser utilizing air pressure, dipping in a flux tank, or the like has been used.

[0003]

However, among the above-mentioned conventional flux coating methods, in the brush coating, the flux coating amount is uneven. In addition, in the method of applying flux using air pressure, the air pressure condition changes due to changes in the temperature of the flux and the amount of flux stored in the tank that stores the flux. It wasn't stable. Even if the flux is evenly applied to the printed circuit board in the flux applying step, since the flux applying step precedes the mounting of the electronic component, the warpage of the printed circuit board or the like may occur before the mounting step of the electronic component. The flux flows out due to the cause. Therefore, in the soldering joining process, the amount of flux was non-uniform. Since the amount of flux is non-uniform in this way, stable bonding is not possible and the amount of flux in electronic parts is uneven,
There was a problem that the wettability of the solder was not stable. Furthermore, when dipping in a flux bath, the same amount of flux is applied to the entire printed circuit board, so the amount of flux cannot be adjusted by the electronic components mounted on the printed circuit board.

Therefore, the present invention has been made to solve the above-mentioned conventional problems, and the purpose thereof is to optimize the application amount of flux according to the electronic parts to be mounted. It is to provide a flux coating device and a coating method thereof that always supply a uniform amount.

[0005]

In order to achieve this object, a flux coating apparatus according to the present invention comprises a storage means for storing the flux while controlling the temperature and the specific gravity, and a flux supplied from the storage means. , A control unit that controls the ejection state of the flux by the piezoelectric pump based on input data from the outside, and a nozzle that guides the flux ejected by the piezoelectric pump to the flux application target portion. It is equipped with and. Therefore, the ejection amount, the ejection speed, or the ejection interval is controlled by the control means in accordance with the type of the electronic component to be coated and the like, which is always kept at the proper temperature and specific gravity. Here, the piezoelectric pump is provided with a piezoelectric actuator including a piezoelectric element that expands and contracts when a voltage is applied, and expands and contracts the piezoelectric actuator by applying a voltage to eject a flux.
Further, in the flux applying method according to the present invention, the flux applying component is mounted on the mounting member, and then the flux is applied to the flux applying target portion of the flux applying component. The surface tension of the flux applied to the flux application target portion prevents the flux from flowing out.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a flux coating apparatus according to the present invention, FIG. 2A is a perspective view showing the same coating state, and FIG. 2B is an enlarged view of portion B in FIG. In these figures, reference numeral 1 is a tank as a storage means for storing flux,
The flux temperature and specific gravity are controlled so that they are always kept optimal.

A piezoelectric pump 2 is provided with a piezoelectric actuator that expands and contracts when a voltage is applied, and the piezoelectric actuator expands and contracts to eject the flux supplied from the tank 1 to a nozzle 4 described later. Data of the pitch of leads 8 of the IC 7 to be described later is inputted as input data from the outside, and a control signal is sent to the piezoelectric pump 3 based on this input signal to control the spouting speed and the spouting interval of the flux. The control unit controls the ejection amount of the flux and also controls the movement position and the movement timing of the nozzle 4, which will be described later.

The nozzle 4 applies the flux 11 ejected from the piezoelectric pump 3 to the IC 7 which is a target portion for flux application.
It is configured to be moved by a moving means (not shown) so that the tip can be moved toward and away from the lead 8. Reference numeral 5 denotes a printed circuit board on which the IC 7 is mounted. A pad 6 on which the leads 8 of the IC 7 are mounted and connected is formed on the surface, and a wiring pattern (not shown) is formed continuously with the pad 6. ing. Reference numeral 9 denotes a suction nozzle connected to a suction pump (not shown), and a suction pad 10 for sucking the IC 7 at its tip.
Is provided.

Next, the flux coating operation by the flux coating apparatus having such a configuration will be described. First, a suction pump (not shown) is operated to suck the air in the suction nozzle 9 to suck the IC 7 by the suction pad 10.
After that, the suction nozzle 9 is moved to lead 8 of the IC 7.
Are mounted on the pads 6 of the printed circuit board 5.

Data of the position of the IC 7 and the pitch of the leads 8 are input to the control unit 3 in advance as input data. Based on the input data, the control unit 3 sends a control signal to a moving unit (not shown) to move the nozzle 4 and bring the tip of the nozzle 4 close to the lead 8 which is the flux application target site. After that, the voltage applied to the piezoelectric actuator (not shown) is controlled by the control unit 3 based on the input data so that the optimum ejection amount of the flux 11 can be obtained for the lead 8 with respect to the piezoelectric pump 2. A control signal for controlling the magnitude and the interval of application is sent to control the ejection speed and the ejection interval of the flux 11.

When the application of the flux 11 to the first lead 8 is completed, the nozzle 4 is moved to the adjacent lead 8 according to the control signal of the controller 3. At the time of this movement, the moving means (not shown) is controlled based on the data of the pitch of the leads 8 which is input in advance.

Since the flux 11 is applied to the leads 8 based on the data input to the controller 3 as described above, even if the pitch of the leads 8 becomes small due to high integration of the IC 7, the leads 8 can be accurately read. An appropriate amount of flux 11 is always applied to various positions. Moreover, tank 1 has flux 1
Since the temperature and the specific gravity of No. 1 are controlled so as to be always kept optimum, the applied amount of the flux 11 is stable without variation, and therefore the quality is improved.

Further, since the flux 11 is applied after the IC 7 is mounted on the printed circuit board 5 and the flux 11 is applied directly to the leads 8, the flux 11 applied to the leads 8 is subjected to surface tension due to surface tension. Flux is blocked by the flux 11
Is evenly applied. For this reason, the amount of flux becomes constant, the joining force by the solder becomes stable, and the wettability of the solder becomes stable.

[0014]

As described above, according to the present invention, the storage means for storing the flux by controlling the temperature and the specific gravity, the piezoelectric pump for ejecting the flux supplied from the storage means, and the piezoelectric pump. By providing a control unit that controls the spouting state of the flux by the electric pump based on an input signal from the outside, and a nozzle that guides the flux spouted by the piezoelectric pump to the target portion for the flux application, Even if the pitch of the parts becomes small, a proper amount of flux is always applied to the part to which the flux is applied, and the quality is improved. Moreover, since the storage means is controlled so that the temperature and the specific gravity of the flux are always kept optimum, the amount of the flux applied is stable without variation, and thus a stable joining force can be obtained.

Further, according to the present invention, the flux applying component is mounted on the mounting member, and then the flux is applied to the flux applying target portion of the flux applying component, so that the flux is directly applied to the flux applying target portion. Since it is applied, the flux applied to the flux application target site is prevented from flowing out from the flux application target site due to the surface tension.
Flux is evenly applied to the part to be applied with flux. For this reason, the amount of flux becomes constant, the joining force by the solder becomes stable, and the wettability of the solder becomes stable.

[Brief description of the drawings]

FIG. 1 is a block diagram of a flux coating device according to the present invention.

FIG. 2A is a perspective view showing a coating state of the flux coating device according to the present invention, and FIG.
It is a part expansion perspective view.

[Explanation of symbols]

1 ... Tank, 2 ... Piezoelectric pump, 3 ... Control part, 4 ... Nozzle, 5 ... Printed circuit board, 6 ... Pad, 7 ... IC, 8 ... Lead, 9 ... Suction nozzle, 10 ... Suction pad.

Claims (2)

(57) [Claims] 1. A storage means for storing the flux by controlling the temperature and the specific gravity, a piezoelectric pump for ejecting the flux supplied from the storage means, and an ejection state of the flux by the piezoelectric pump from the outside. 2. A flux applying device, comprising: a control unit that controls based on the input data of 1. and a nozzle that guides the flux ejected by the piezoelectric pump to a flux applying target portion. 2. A flux applying method according to claim 1, wherein the flux applying device is mounted on a mounting member, and then the flux is applied to a flux applying target portion of the flux applying component.