JPH07321452A - Flux adhesion method and device - Google Patents

Abstract

PURPOSE:To uniformly and positively bond flux on the surface of a surface- mount-type IC bump such as a ball-grid-array type IC. CONSTITUTION:A container 5 stores melted flux 7, mechanical vibration is applied to the melted flux by an ultrasonic vibration generator 11, an IC 2 retained by a suction nozzle 3 is dropped, a bump 2B is dipped into the vibrating melted flux 7, and flux is positively adhered to the surface of the bump 2B properly without depending on the surface shape and size of the bump while the surface tension of the melted flux 7 of the part where the bump 2B is dipped is weakened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface of an electrode terminal of an electronic component such as a surface mount type IC having electrode terminals such as bumps formed on one surface such as a ball grid array type IC. The present invention relates to a flux attachment method and apparatus capable of attaching flux.

[0002]

2. Description of the Related Art A conventional flux depositing method and apparatus will be described with reference to FIG. FIG. 2 is a side view conceptually showing a conventional flux transfer device. In addition,
In the following description, a surface mount type IC (hereinafter, simply referred to as “I
The description will be made by taking "C" as an example.

Reference numeral 1 generally refers to a prior art flux depositing device. The flux adhering device 1 is composed of an adsorption nozzle 3 for adsorbing the package 2P side of the IC 2 and a container 5 for accommodating the molten flux 7.

The suction nozzle 3 is, for example, a prism having a quadrangular cross section with a through hole 4 for suction formed in the center thereof, and the through hole 4 is connected to a suction pump (not shown). ing. Further, the adsorption nozzle 3 is supported by a supporting device (not shown) so as to be movable up and down with respect to the surface of the molten flux 7 contained in the container 5. On the other hand, the container 5 is formed with a shallow and flat recess 6 for accommodating the molten flux 7, and a small amount of the molten flux 7 can be accommodated in the recess 6.

The IC 2 has bumps 2B, which are electrode terminals, on the surface (hereinafter, simply referred to as "rear surface") opposite to the surface (hereinafter, simply referred to as "front surface") of the package 2P which is adsorbed by the adsorption nozzle 3 of the package 2P. Are formed in plural. For example, the package 2P of this IC2 has a surface area of 16 mm square,
The bump 2B has a height of about 50 μm and a diameter of 100 μm.
Then, it is assumed that 400 packages are formed in the peripheral portion of the back surface of the package 2P at a pitch of about 150 μm.

Next, a method of attaching flux to the bump 2B of the IC 2 using the flux attaching apparatus 1 will be described. By operating a suction pump (not shown), the suction nozzle 3 sucks and holds the surface of the package 2P of the IC 2 in a predetermined direction, and then the holding device (not shown) while keeping the held state. Is further operated to lower the adsorption nozzle 3 to bring the bump 2B of the IC 2 into contact with the surface of the molten flux 7 contained in the container 5. When the bump 2B comes into contact with the surface of the molten flux 7, the operation of the supporting device is reversed and the suction nozzle 3 is immediately pulled up. By controlling the suction nozzle 3 in this manner, the flux is sequentially attached to the surface of the bump 2B of the IC 2.

[0007]

Generally, the bumps 2B have fine irregularities on the surface thereof, so that the molten flux tends to be difficult to uniformly adhere to the bumps. Further, the size and height of the plurality of bumps formed on one IC are not always uniform. When the molten flux is attached to the bump by the above-described flux attaching method using the flux attaching apparatus 1, if the wettability of the bump to the molten flux is poor as described above, the bump However, the amount of the molten flux that must be attached to the bumps is reduced, and the molten flux cannot be uniformly attached to all the bumps. An object of the flux adhesion method and apparatus of the present invention is to eliminate such drawbacks.

[0008]

Therefore, according to the present invention,
IC in a state where mechanical vibration is applied to molten flux
The above-mentioned problem was solved by adopting a flux attachment method of attaching molten flux to the surface of the bump. Further, according to the present invention, as a means of a flux adhering device capable of executing this flux adhering method, in the present invention, a container for accommodating the molten flux and a mechanical vibration generation for applying mechanical vibration to the molten flux contained in the container The flux adhesion device is configured by the device and the adsorption nozzle that adsorbs the IC on which the bump is formed and dips the bump in the vibrating molten flux to solve the above problems. Furthermore, an acoustic microphone is attached to the suction nozzle of the flux adhering device, and the IC adsorbed by the suction nozzle is attached.
When the bumps of the
The problem was solved by providing a mechanism that detects the vibration and controls the movement of the suction nozzle so that the immersion depth position can be controlled from the surface of the molten flux of the bump.

[0009]

Therefore, when mechanical vibration is applied to the molten flux, the energy of the mechanical vibration is concentrated on the minute recesses formed by the bump contacting the molten flux, and the surface tension of the molten flux is substantially reduced. Therefore, the wettability of the molten flux to the bumps is improved.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the flux adhering device of the present invention will be described with reference to FIG. FIG. 1 is a side view conceptually showing one embodiment of the flux transfer device of the present invention. In addition,
The same components as those of the conventional flux depositing apparatus are designated by the same reference numerals, and their description will be omitted.

This flux depositing device 10 basically comprises a suction nozzle 3 and a container 5 in which a recess 6 for containing a molten flux 7 is formed, like the flux depositing device 1 of the prior art. An ultrasonic vibration generator 11 is attached to the back side of the container 5 opposite to the recess 6. This ultrasonic vibration generator 11, for example, the frequency is 1
Ultrasonic vibration of 00 KHz and an output of about 1 W is emitted. In this embodiment, in order to transmit ultrasonic vibrations to the molten flux 7 as efficiently as possible, a recess 12 is formed on the back side of the container 5 opposite to the recess 6, and an ultrasonic vibration generator 11 is installed in this recess 12. Is configured.

On the other hand, a mechanical-electrical conversion element 13 such as a microphone or a piezoelectric element capable of detecting the ultrasonic vibration is attached to the side surface of the suction nozzle 3 for sucking the IC 2.
The suction nozzle 3 is formed of, for example, a 15 mm square prism, and has a through hole 4 for suction having a diameter of 1 mmφ formed in the center thereof.

The suction nozzle 3 has a drive motor 15 fixed to a supporting portion 14 which is located at a reference height position which is located above, and a male screw 1 of the drive motor 15.
6 is formed vertically and is driven up and down by a drive device 20 including a female screw 18 which is screwed into the male screw 16 and which is formed inside, and a screw receiving member 19 fixed to the side surface of the suction nozzle 3. It

A length measuring device 21 such as a laser beam is fixed to the supporting portion 14, while a horizontal plate 22 serving as a reference surface is fixed to the upper end surface of the screw receiving member 19, for example. In addition, a function of accurately controlling the height position of the suction nozzle 3 is added by these. Reference numeral 23 is a device for preventing screw backlash.

Next, the flux depositing apparatus 10 of the present invention
A method of attaching the molten flux 7 to the plurality of bumps 2B formed on the IC 2 by using will be described. First, the ultrasonic vibration generator 11 is operated to generate ultrasonic vibration, and mechanical vibration is applied to the molten flux 7 therein through the container 5.

With mechanical vibration of ultrasonic waves being applied to the molten flux 7, a suction pump (not shown) is then actuated to cause the suction nozzle 3 to move the IC 2 in a predetermined direction so that the surface of the package 2P is covered. After sucking and holding, then, while keeping the holding state, the drive motor 15 is operated to lower the suction nozzle 3, and the bump 2B of the IC 2 is held.
Is brought into contact with the surface of the molten flux 7 contained in the container 5. When the bump 2B comes into contact with the surface of the molten flux 7, the mechanical vibration of the ultrasonic waves causes the molten flux 7,
The mechanical-electrical conversion element 13 is reached through the bump 2B,
It can be detected that the bump 2B is in contact with the molten flux 7.

In this case, since the bumps 2B have variations, in order to absorb the variations, the suction nozzle 3 is further moved down by a minute distance. For example, 10 μm
Lower it to some extent. This minute amount of control is performed for a certain period of time after the ultrasonic vibration is detected by the mechanical-electrical conversion element 13.
The driving motor 15 is continuously operated and the male screw 16 is rotated to perform the operation. Alternatively, the length measuring device 21 and the horizontal plate 22 may be used.

In this way, the suction nozzle 3 is lowered by a minute amount, the bumps 2B are immersed in the molten flux 7 for a predetermined time, and then the drive motor 15 is reversed to pull up the suction nozzle 3. After that, if such an operation is repeated, the molten flux can be attached to the bumps of the IC one after another.

Therefore, even if the surface properties of the bump 2B are not good, by applying mechanical vibration to the molten flux 7, the energy of mechanical vibration is generated by the bump 2B coming into contact with the molten flux. Further, the molten flux concentrates on the minute recesses and substantially lowers the surface tension of the molten flux, so that the molten flux easily adheres to the surfaces of the bumps and the wettability thereof is improved.

In the above embodiment, the detection of the time when the bump comes into contact with the molten flux is carried out by the ultrasonic vibration mechanical-electrical conversion element 13, but it may be carried out by using the capacitance. Well, the point is that any means can be used as long as it can detect the time when the bump comes into contact with the molten flux.

[0021]

As described above, according to the flux depositing method and apparatus of the present invention, the flux deposit amount is increased even in bumps having poor wettability, and flux can be deposited to the upper part of the bumps. Even if there is some deformation in each bump, the variation can be ignored.

[Brief description of drawings]

FIG. 1 is a side view conceptually showing one embodiment of a flux transfer device of the present invention.

FIG. 2 is a side view conceptually showing a conventional flux transfer device.

[Explanation of symbols]

 2 IC (Surface Mounted IC) 2B Bump (Electrode Terminal) 2P Package 3 Adsorption Nozzle 4 Through Hole 5 Container 6 Recess 7 Melt Flux 10 Flux Adhering Device 11 Ultrasonic Vibration Generator 12 Recess 13 Mechanical-electrical conversion element 14 Support part 15 Drive motor 16 Male screw 17 Shaft 18 Female screw 19 Screw receiving member 20 Drive device 21 Length measuring device 22 Horizontal plate 23 Screw backlash prevention device

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location B05D 7/14 P B23K 3/00 Q H01L 21/321

Claims (3)

[Claims] 1. A method for depositing a flux, which comprises depositing the molten flux on the surface of an electrode terminal formed on an electronic component in a state where mechanical vibration is applied to the molten flux. 2. A container for containing a molten flux, a mechanical vibration generator for applying mechanical vibration to the molten flux contained in this container, and an electronic component having an electrode terminal adsorbed and vibrated. A flux adhering device comprising: an adsorption nozzle for immersing the electrode terminal in the molten flux. 3. A mechanical-electrical conversion element is attached to the suction nozzle, and when the electrode terminal of the electronic component sucked by the suction nozzle comes into contact with the molten flux, the mechanical vibration is detected to detect the electrode terminal. The flux adhering device according to claim 2, wherein the movement of the adsorption nozzle is regulated so that the immersion depth position can be controlled from the surface of the molten flux.