JP3526738B2 - Mounting device and mounting method for spherical solder - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for mounting spherical solder, particularly fine spherical solder, on electronic parts.

[0002]

2. Description of the Related Art In recent years, electronic devices have become lighter, thinner, shorter and smaller, so that electronic components used in electronic devices have become smaller and more multifunctional. In order to make an electronic component multi-functional, it is necessary to incorporate a large number of ICs inside the component and pull out a large number of leads from the ICs. Therefore, it is necessary to install a large number of leads outside. QFP, SOIC
These electronic components have a large number of leads on both sides or four sides of the component body. However, since QFP, SOIC, etc., have leads installed on the side surface of the main body, the number of leads is limited, and no matter how narrow the lead interval is, the number of leads installed is at most 200.
It was about a book.

Therefore, today, the BGA (Ball), which has more leads than QFP and SOIC and is more multifunctional, is used.
Grid Array), CSP (Chip Siz)
High-performance electronic components such as ePackage) and flip chips have appeared. In BGA and CSP, a chip element is mounted on the upper surface of a substrate, and dot-shaped leads connected to the chip element are provided on the back surface of the substrate at lattice positions. In the flip chip, dot-shaped leads are directly provided on the back surface of the IC. Since high-performance electronic components such as BGA, CSP, and flip-chip are provided with dot-shaped leads on a wide area, a large number of leads can be installed, and the function is excellent accordingly.

In order to mount this high-performance electronic component on a printed circuit board, solder bumps are formed in advance on the leads of the high-performance electronic component, the bumps are placed in accordance with the mount of the printed circuit board, and then the solder bumps are mounted. Melt and solder. To form the solder bumps, flux is applied to the dot-shaped leads of the high-performance electronic component, the spherical solder is placed on the spot-shaped leads, and then heated by a heating device such as a reflow furnace to melt the spherical solder.

The mounting of spherical solder on high-performance electronic parts is
The suction head having a large number of suction holes is set so that the suction holes face downward, and the suction head is brought close to a storage container containing a large number of spherical solder. Then, the suction head is in a vacuum state, that is, in a state where it is sucked from the suction hole, and the spherical solder in the storage container is sucked into the suction hole of the suction head.

At this time, if the suction head is kept in a vacuum state, the spherical solder does not necessarily come into contact with all the suction holes. Therefore, even if the suction head is brought close to the spherical solder in the storage container, all the suction holes will be spherical. It cannot absorb solder. Therefore, after the suction head is brought close to the storage container, gas is blown out from the bottom surface of the storage container to lift up the spherical solder, and the lifted spherical solder is adsorbed in the suction hole of the suction head (floating method: JP-A-7-
No. 307340), the storage container is vibrated and the randomly moving spherical solder is adsorbed to the adsorption holes (vibration method: JP-A-7-307296), or the adsorption head is accommodated with the adsorption head after fitting the adsorption head into the accommodation container. The container is rotated by a certain angle to roll the spherical solder on the surface of the suction hole of the suction head so that the spherical solder is sucked into the suction hole (rotating method: JP-A-8-255997).

Generally, most of the spherical solders used for BGA have a diameter of 0.76 mm, and for BGAs of a slightly small size, 0.5 mm diameter spherical solder may be used. However, when it comes to CSPs, spherical solders having a diameter of 0.3 mm or less, particularly very small CSPs and flip chips of recent years, which have a very small diameter of 0.15 mm, have come to be used.

[0008]

When the spherical solder having a diameter of 0.76 mm used in the BGA is adsorbed to the adsorption head by the floating method, the vibration method, the rotation method, etc., and then the storage container and the adsorption head are separated from each other. In addition, the spherical solder adhered to places other than the suction holes falls into the storage container by its own weight, and most of them do not adhere to the suction heads other than the suction holes. However CSP
Spherical solder having a diameter of 0.3 mm or less, which is used for flip chips or the like, may remain attached to a portion other than the adsorption hole when it is adsorbed by the adsorption head and then separated from the storage container.

The cause of this is that when minute spherical solder is suspended in a gas or moved by vibration or rotation, the spherical solder is rubbed with each other or between the spherical solder and the wall surface of the storage container to be charged with static electricity. Because of this static electricity, the spherical solder adheres to unnecessary portions (hereinafter simply referred to as unnecessary portions) other than the suction holes of the suction head.

As described above, the CS is attached to the unnecessary portion.
When spherical solder is mounted on P or flip chip, the spherical solder becomes excessively mounted, and when the spherical solder is melted by heating in a reflow furnace after mounting, two spherical solders are fused at one bump formation location. As a result, defects such as excessive bumps or adjacent bumps forming a bridge with each other may occur.

It is an object of the present invention to provide a method and apparatus for mounting spherical solder in which only the spherical solder adhered to an unnecessary portion due to static electricity is completely removed and over-mounting never occurs.

[0012]

[Means for Solving the Problems] As means for removing the minute spherical solder adhering to unnecessary portions of the suction head by static electricity, sweeping the suction head with a brush, giving a shock to the suction head, or sucking the suction head It is conceivable to blow gas to the head.

The sweeping means with a brush also removes the necessary spherical solder adsorbed in the adsorption holes when the bristles of the brush are strong or the tips of the brush hit the adsorption head deeply. Therefore, there is a problem that it is very difficult for the sweeping means to select the bristles of the brush and adjust the degree of contact with the suction head.

Although the impacting means to the suction head is effective in removing the spherical solder adhered to the unnecessary portion to some extent, the removal state changes depending on the strength of the impact and the location to which the impact is applied. However, it takes time and effort to change them depending on the size of the spherical solder, the number of mounted spherical solders, and the like.

The gas blowing means is capable of removing the spherical solder at an unnecessary portion only by adjusting the blowing strength according to the size of the spherical solder, and the adjustment factor is smaller than that of other means, so that the adjustment is easy. Is. However, the gas spraying means, when the gas is sprayed, the spherical solder adhered to unnecessary portions scatters,
It takes time to collect them.

Therefore, the inventor of the present invention scatters the spherical solder when it blows a gas, but on the contrary, if the spherical solder is sucked together with the gas, there is no fear of collecting the spherical solder, and the spherical solder adhered to the unnecessary portion is completely removed. The present invention has been completed by focusing on the fact that it can be done.

According to the present invention, in a method of mounting a spherical solder in which a spherical solder sucked in a suction hole of a suction head is mounted at a predetermined position of an electronic component, after sucking the spherical solder in the suction hole of the suction head, suction is performed. By sucking gas with the nozzle, it is a mounting method of spherical solder, which is characterized by sucking unnecessary spherical solder adhering to places other than the suction holes into the suction nozzle, and also a large number of suction holes. A perforated suction head is provided, and a suction nozzle having a suction port longer than the length from one end to the other end of the suction hole is provided at a position facing the suction head.
The spherical solder mounting apparatus is characterized in that a suction nozzle or a suction head is movable in parallel at opposed positions.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION According to the present invention, the spherical solder adhered to an unnecessary portion can be removed only by sucking it together with the gas. However, if the impacting means for the suction head is also used, the removal can be performed more reliably. become. This is because when a large amount of spherical solder adheres to one place, the weight of the spherical solder becomes heavy, and if the suction force is not sufficient, it is feared that all the spherical solder cannot be sucked at once. Therefore, if you give a shock to the suction head and remove the large amount of spherical solder that has adhered in advance by the shock to the suction head, then move the suction nozzle closer to remove the spherical solder that has adhered to unnecessary points. It is possible to remove the necessary spherical solder and remove only the spherical solder attached to unnecessary portions.

As described above, most of the 0.76 mm diameter spherical solder for BGA drops by its own weight when it adheres to an unnecessary portion, but even the 0.76 mm diameter spherical solder has a large amount of static electricity and its own weight. The present invention can also be applied to a device that does not fall. However, spherical solder having a diameter of 0.3 mm or less is likely to be attached to an unnecessary portion due to electrostatic charging, and the present invention exhibits the most excellent effect on the spherical solder having a diameter of 0.3 mm or less. .

In the present invention, the suction head may face downward or upward, and the suction head may be fixed to move the suction nozzle, or the suction nozzle may be fixed to move the suction head. The distance between the suction head and the suction nozzle should be as close as possible, but they must be separated by at least the diameter of the spherical solder. because,
This is because if the distance is smaller than the diameter of the spherical solder, the suction nozzle scrapes off the spherical solder attached to the suction holes when the suction nozzle or the suction head is moved. However, if the distance between the suction head and the suction nozzle is too large, the suction force of the suction nozzle with respect to the suction head becomes weak, and it becomes impossible to suck the spherical solder attached to the unnecessary portion. A suitable distance between the suction head and the suction nozzle is approximately twice the diameter of the spherical solder.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a spherical solder mounting apparatus of the present invention, and FIG. 2 is a front sectional view of the same.

The suction head 1 has a box shape with a hollow inside. A suction plug 2 communicating with the inside is installed on the side surface of the suction head 1, and the suction plug is connected to a suction device (not shown). Further, the lower part of the suction head 1 is provided with a plurality of suction holes 3 at a position corresponding to a bump forming position of the electronic component.
.. are the adsorbing surfaces 4 on which holes are formed. A transparent tempered glass 5 is fitted in the upper portion of the suction head 1 in a hermetically sealed state. The reason why the upper portion is made of transparent tempered glass is to detect the suction state of the spherical solder in the suction holes. . That is, after the spherical solder is adsorbed by the adsorption holes, laser light or halogen light is emitted from above the adsorption head, and the light is received by the light receiving device installed below the adsorption head. At this time, if the spherical solder is not adsorbed even in one of the adsorption holes, light passes through the adsorption hole and is received by the light receiving device below. Then, the non-adsorption is notified by an alarm, or the adsorption step is performed again.

The suction nozzle 6 has a hollow inside, and a net 7 is stretched at substantially the center thereof, and the inside is divided into an upper step portion 8 and a lower step portion 9. The mesh size of the mesh 7 is smaller than that of the spherical solder used for mounting, so that the spherical solder does not pass through. A horizontally long suction port 1 is provided above the suction nozzle 6.
0 is formed, and its length in the longitudinal direction is longer than the length from the end to the end of the suction hole formed in the suction head.

A suction plug 11 communicating with the outside is installed in the lower portion 9 of the suction nozzle 6, and the suction plug is connected to a suction device (not shown). The suction nozzle 6 is installed at a lower portion of the suction head 1 with the suction port 10 facing upward, and is spaced apart from the suction head 1 so as to move in parallel in the direction of arrow A.

In the embodiment, the suction nozzle is moved below the fixed suction head with the suction hole on the lower side, but the suction nozzle may be fixed and the suction head may be moved. Alternatively, a suction nozzle with the suction hole facing upward and the suction port facing downward may be installed on the suction head.

An impact device 12 is installed on the suction head 1. The impact device 12 moves up and down in the arrow X direction to impact the suction head.

Next, a method of mounting spherical solder using the above-described spherical solder mounting apparatus will be described.

The spherical solder Q is sucked onto the suction surface 4 of the suction head 1 by using a device (not shown) that employs a floating method, a vibration method, a rotation method, or the like. At this time, the spherical solder H charged with static electricity is attached to an unnecessary portion of the adsorption surface 4. After the spherical solder is sucked onto the suction surface 4, first, the shock head is shocked by the shock device 12 to remove a large amount of the spherical solder adhered to unnecessary portions. At this time, only the impact on the suction head does not remove all the spherical solder adhered to the unnecessary portions.

Thereafter, the suction nozzle 6 is moved below the suction head 1 as shown by arrow A. The suction nozzle 6 is sucked from a suction plug 11 by a suction device (not shown), has a negative pressure inside, and sucks external gas from the suction port 10.

Since the spherical solder adhered to the unnecessary portion of the adsorption surface 4 is electrostatically adhered, the adhesion force is weak, and it is sucked by the suction force from the suction nozzle installed a little away from the suction surface. The spherical solder sucked by the suction holes 3 is not sucked by the suction force of the suction nozzle. Therefore, the spherical solder adhered to the unnecessary portion of the suction surface is completely sucked into the suction nozzle, and only the spherical solder sucked in the suction holes remains.

The spherical solder sucked into the suction nozzle is
It is stopped by the net 7 and remains on the upper stage 8. When the removal of the spherical solder adhered to the unnecessary portion of the suction head is completed, the suction nozzle stops the suction, and the suction nozzle is reversed to turn the upper part 8
Collect the remaining spherical solder and use it again for mounting.

In this way, the suction head from which the spherical solder attached to the unnecessary portions is removed is irradiated with light from above by a light emitting device (not shown). The light emitted from above the suction head passes through the transparent tempered glass 5 of the suction head 1 and enters each suction hole 3 from above. At this time, where the spherical solder is not adsorbed in the adsorption holes, light passes through the adsorption holes and reaches a light receiving device (not shown) installed below.
Upon receiving the light, the light receiving device detects that the suction head has not been sucked, and issues an alarm or issues a command to restart the suction process again.

The suction head in which the spherical solder is not attached to unnecessary portions and the spherical solder is adsorbed in all the adsorption holes moves to an electronic component (not shown), and the spherical solder is applied to the bump forming portion of the electronic component to which the flux is applied. Equipped with. The electronic component on which the spherical solder is mounted is heated by a heating device such as a reflow furnace, and the spherical solder is melted to form bumps.

In the present invention, when the spherical solder having a diameter of 0.15 mm was mounted on the CSP having 225 bump formation points, there was no excessive mounting or non-mounting of the spherical solder.

[0035]

As described above, according to the present invention,
Since the minute spherical solder that easily adheres to the adsorption surface due to static electricity can be completely removed from unnecessary locations, excessive bumps, bridges, and other defects do not occur, and reliable mounting is possible. And an excellent effect that cannot be obtained with the device.

[Brief description of drawings]

FIG. 1 is a perspective view of an apparatus for mounting spherical solder according to the present invention.

FIG. 2 is a front view of an apparatus for mounting spherical solder according to the present invention.

[Explanation of symbols]

1 Suction head 2 suction plug 3 adsorption holes 4 Adsorption surface 5 tempered glass 6 suction nozzle 7 net 8 Upper part 9 Lower part 10 Suction port 11 Suction plug 12 Impact device

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Claims (2)

(57) [Claims] 1. A spherical solder mounting apparatus for mounting spherical solder sucked in a suction hole of a suction head at a predetermined position of an electronic component, the suction head having a large number of suction holes and an impact device. Is installed, and a suction nozzle having a suction port longer than the length from end to end of the suction hole is installed at a position facing the suction head, and the suction nozzle or the suction head is at a facing position. The spherical solder mounting device is characterized in that it can move in parallel. 2. The suction hole of the suction head according to claim 1.
Mount the attracted spherical solder at a predetermined position on the electronic component.
Spherical solder mounting method using a spherical solder mounting device, wherein after sucking the spherical solder in the suction hole of the suction head, the suction head is impacted and then the gas is sucked by the suction nozzle. The method for mounting spherical solder according to claim 1, wherein unnecessary spherical solder adhered to a portion other than the suction holes is sucked into the suction nozzle.