JPH11224917A - Mounting of spherical solder and device thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove completely spherical solders adhered to undesired places on an adsorption surface formed o the lower part of an adsorption head by a method, wherein after the solders are made to adsorb in absorption holes bored in the adsorption surface formed on the lower part of the head, and gas is sucked in a suction nozzle to suck the undesired spherical solders adhered to places other than the holes on the adsorption surface in the suction nozzle. SOLUTION: An absorption surface with a plurality of adsorption holes 3 bored in places, which agree with bump formation places on an electronic component, on the adsorption surface is formed on the lower part of an adsorption head 1. After spherical solders Q have been made to absorb in the absorption surface, shocks are inflicted on the head 1 by a shock unit 12, and the solders Q adhered to undesired places on the adsorption surface in large quantities are removed. After that, a suction nozzle 6 is moved under the lower part of the head 1 as shown by an arrow A, gas in the outside is sucked in the nozzle 6 through a suction port 10 by a suction unit to exhaust the sucked gas to the outside through an intake plug 11 of the nozzle 6, the solders Q sucked in the nozzle 6 are stopped by a net 7 to contrive so as to stop the solders Q in an upper step part 8 and the removal of the solders is ended.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art In recent years, as electronic devices have become lighter, thinner and smaller, electronic components used in the electronic devices have become smaller and more multifunctional. In order to make an electronic component multifunctional, a large number of ICs must be incorporated in the component and a large number of leads must be drawn from the IC. Therefore, it is necessary to provide as many external leads as possible. The multifunctional electronic components include QFP, SOIC
These electronic components have a large number of leads on both sides or four sides of the component body. However, since QFPs and SOICs, etc., have leads installed on the side surface of the main body, the number of leads is limited.
It was about a book.

[0003] Therefore, today, BGAs (Balls) which have more functions by adding more leads than QFPs and SOICs have been developed.
Grid Array), CSP (Chip Siz)
High-performance electronic components such as ePackage) and flip chips have emerged. The BGA or CSP has a chip element mounted on an upper surface of a substrate, and dot-like leads connected to the chip element are provided at lattice positions on the back surface of the substrate. The flip chip has a point-like lead directly provided on the back surface of the IC. High-performance electronic components such as BGA, CSP, and flip-chip are provided with point-like leads in a wide area, so that a large number of leads can be provided, and the function is excellent.

In order to mount this high-performance electronic component on a printed circuit board, a solder bump is formed in advance on the lead of the high-performance electronic component, and the bump is mounted in accordance with the mounting of the printed circuit board. Is melted and soldered. In the method of forming the solder bumps, a flux is applied to a point-like lead of a high-performance electronic component, a spherical solder is placed thereon, and then heated by a heating device such as a reflow furnace to melt the spherical solder.

[0005] Mounting of spherical solder on high-performance electronic parts
The suction head having a large number of suction holes is placed so that the suction holes face downward, and the suction head is brought closer to a storage container containing a large number of spherical solders. Then, with the suction head in a vacuum state, that is, in a state of being sucked through the suction hole, 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 left in a vacuum state, the ball solder does not always come into contact with all the suction holes. It cannot absorb solder. Then, after bringing the suction head close to the storage container, a gas is blown out from the bottom surface of the storage container to lift up the spherical solder, and the lifted spherical solder is sucked into the suction hole of the suction head (floating method: Japanese Patent Laid-Open No. 7-1995).
No. 307340), a spherical solder, which moves randomly by vibrating a storage container, is sucked into a suction hole (vibration method: Japanese Patent Application Laid-Open No. 7-302796), or a suction head is fitted into the storage container and then stored with the suction head. The spherical solder is sucked into the suction holes by rotating the container at a fixed angle and rolling the spherical solder on the suction holes of the suction head (rotation method: JP-A-8-255997).

In general, most of the spherical solders used for the BGA have a diameter of 0.76 mm, and in the case of a slightly smaller BGA, a spherical solder having a diameter of 0.5 mm may be used. However, in the case of a CSP, a very small spherical solder having a diameter of 0.3 mm or less is used for a spherical solder, and particularly a recent ultra-compact CSP or flip chip has a diameter of 0.15 mm.

[0008]

The spherical solder having a diameter of 0.76 mm used in the BGA is sucked to the suction head by a floating method, a vibration method, a rotation method, or the like, and then separated from the storage container and the suction head. Meanwhile, the spherical solder that has adhered to portions other than the suction holes falls into the storage container by its own weight, and most of the solder does not adhere to the suction head other than the suction holes. However CSP
In some cases, a spherical solder having a diameter of 0.3 mm or less, such as used for a chip or a flip chip, is adsorbed to a suction head and then separated from a storage container, so that it may remain attached to a portion other than the suction hole.

[0009] This is because when the minute spherical solder is suspended in gas or moved by vibration or rotation, it is rubbed between the spherical solders or between the spherical solder and the wall surface of the storage container and becomes charged with static electricity. Because of this, the static electricity causes the spherical solder to adhere to unnecessary portions other than the suction holes of the suction head (hereinafter, simply referred to as unnecessary portions).

[0010] As described above, CS is adhered to unnecessary portions.
When spherical solder is mounted on P or flip chip, the spherical solder becomes excessively mounted, and when it is heated in a reflow furnace to melt the spherical solder, two spherical solders are fused at one bump formation location As a result, an excessively large bump is generated, or a defect that adjacent bumps are integrated to form a bridge is generated.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method and an apparatus for mounting a spherical solder in which only the spherical solder attached to an unnecessary portion due to static electricity is completely removed and no excessive mounting is caused.

[0012]

As means for removing minute spherical solder adhered to unnecessary portions of a suction head by static electricity, sweeping the suction head with a brush, applying an impact to the suction head, or performing suction or suction. It is conceivable to blow gas on the head.

[0013] The sweeping means using a brush removes even the necessary spherical solder adsorbed in the suction holes if the brush bristles are strong or the tips of the brushes hit the suction head deeply. Therefore, there is a problem that it is very difficult for the sweeping means to select the bristles of the brush and to adjust the degree of contact with the suction head.

Although the means for impacting the suction head is effective for removing the spherical solder adhering to an unnecessary part to a certain extent, the state of removal varies depending on the strength of the shock and the place where the shock is applied. However, it is time-consuming to change the size of the spherical solder and the number of mounted spherical solders as needed.

[0015] The gas blowing means is capable of removing unnecessary spherical solder only by adjusting the blowing strength according to the size of the spherical solder, and has a smaller adjustment factor than other means, so that adjustment is easy. It is. However, when the gas is sprayed, the spherical solder attached to unnecessary portions when the gas is sprayed scatters,
It takes time to recover it.

The inventor of the present invention has proposed that, when the gas is blown, the spherical solder is scattered. On the contrary, if the spherical solder is sucked together with the gas, there is no need to recover the spherical solder, and the spherical solder adhered to unnecessary portions is completely removed. Focusing on what can be done, the present invention has been completed.

The present invention relates to a method of mounting a spherical solder at a predetermined position on an electronic component, wherein the spherical solder sucked in the suction hole of the suction head is mounted on the electronic component. This is a method of mounting spherical solder, in which unnecessary gas solder adhering to places other than the suction holes is sucked into the suction nozzle by sucking gas with the nozzle. A perforated suction head is installed, and at a position facing the suction head, a suction nozzle having a suction port longer than the length from end to end of the suction hole is installed,
A spherical solder mounting device, wherein a suction nozzle or a suction head is movable in parallel at an opposing position.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, the removal of the spherical solder adhering to an unnecessary portion can be carried out only by sucking it together with the gas. become. This is because if a large amount of spherical solder adheres to one location, the weight of the spherical solder becomes heavy, and if the suction force is not sufficient, all the spherical solder may not be able to be sucked at once. Therefore, by applying a shock to the suction head, this large amount of spherical solder adhered to the suction head is removed in advance by an impact to the suction head, and then a suction nozzle is approached to remove the spherical solder attached to unnecessary parts. The necessary spherical solder can be left, and only the spherical solder attached to unnecessary portions can be removed.

As described above, most of the 0.76 mm-diameter spherical solder for BGA drops under its own weight when it adheres to an unnecessary portion. However, 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 case where the object does not fall. However, it is often the case that the spherical solder having a diameter of 0.3 mm or less easily adheres to unnecessary portions due to electrostatic charging, and the present invention exerts 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 be directed downward or upward, or the suction head may be fixed to move the suction nozzle, or the suction nozzle may be fixed and the suction head moved. The distance between the suction head and the suction nozzle is preferably as close as possible, but must be at least as large as the diameter of the spherical solder. 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 hole 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 in the spherical solder attached to an 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 mounting device for a spherical solder according to 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 provided on a side surface of the suction head 1, and the suction plug is connected to a suction device (not shown). The lower part of the suction head 1 is provided with a plurality of suction holes 3 at positions corresponding to the bump formation positions of the electronic component.
.. Are suction surfaces 4 provided with holes. A transparent tempered glass 5 is fitted into the upper part of the suction head 1 in a state where the inside is sealed. The reason why the upper part is made of a transparent tempered glass is to detect the suction state of the spherical solder in the suction hole. . That is, after the spherical solder is adsorbed by the suction holes, laser light or halogen light is irradiated from above the suction head, and the light is received by a light receiving device installed below the suction head. At this time, if the spherical solder is not adsorbed to any one of the suction holes, light passes through the suction hole and is received by the lower light receiving device. Then, the non-adsorption is notified by an alarm, or the adsorption step is performed again.

The suction nozzle 6 has a hollow inside, a net 7 stretched substantially in the center, and is internally divided into an upper portion 8 and a lower portion 9. The size of the mesh of the net 7 is smaller than the spherical solder used for mounting, so that the spherical solder does not pass through. At the top of the suction nozzle 6 is a horizontally long suction port 1
0 is formed, and the 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.

At the lower part 9 of the suction nozzle 6, a suction plug 11 communicating with the outside is provided, and the suction plug is connected to a suction device (not shown). The suction nozzle 6 is spaced apart from the lower part of the suction head 1 with the suction port 10 facing upward, and moves parallel to the direction of arrow A.

In this embodiment, the suction nozzle is moved below the fixed suction head having the suction hole on the lower side. However, 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.

The suction head 1 is provided with an impact device 12. The impact device 12 moves up and down in the direction of arrow X to apply an impact to the suction head.

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

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

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

The spherical solder adhering to unnecessary portions of the suction surface 4 has a weak adhesion because it is adhered by static electricity, and is sucked by a suction force from a suction nozzle provided a little away from the suction surface. The spherical solder sucked in the suction hole 3 is not sucked by the suction force of the suction nozzle. Therefore, the spherical solder adhering to an unnecessary portion of the suction surface is completely sucked into the suction nozzle, and only the spherical solder sucked in the suction hole remains.

The spherical solder sucked into the suction nozzle is
It is stopped by the net 7 and remains in the upper section 8. When the removal of the spherical solder adhering to the unnecessary part of the suction head is completed, the suction by the suction nozzle is stopped, and the suction nozzle is turned over so that the upper portion 8 is removed.
The remaining spherical solder is recovered and used for mounting again.

The suction head from which the spherical solder adhered to unnecessary portions has been removed in this way is irradiated with light from above by a light emitting device (not shown). 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 sucked into the suction hole, the light passes through the suction hole and reaches a light receiving device (not shown) installed below.
The light receiving device that has received the light detects that the suction head has not been suctioned, and issues a warning or issues a command to restart the suction process.

The suction head, in which no spherical solder adheres to unnecessary portions and the spherical solder is sucked in all the suction holes, moves to an electronic component (not shown), and moves to the flux-coated electronic component in a bump forming portion of the electronic component. With. Then, 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 a spherical solder having a diameter of 0.15 mm was mounted on a CSP having 225 bump forming portions, no excessive or no spherical solder was mounted.

[0035]

As described above, according to the present invention,
A conventional mounting method that can reliably remove the minute spherical solder that adheres to the adsorption surface easily due to static electricity from unnecessary parts, eliminating excessive bumps and bridges due to excessive mounting, and enabling reliable bonding It has an excellent effect that cannot be obtained with a device.

[Brief description of the drawings]

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

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Suction head 2 Suction plug 3 Suction hole 4 Suction surface 5 Tempered glass 6 Suction nozzle 7 Net 8 Upper part 9 Lower part 10 Suction port 11 Suction plug 12 Impact device

Claims (3)

[Claims] In a method of mounting a spherical solder at a predetermined position on an electronic component, the spherical solder sucked in the suction hole of the suction head is mounted on the electronic component. By sucking gas,
A method for mounting a spherical solder, wherein unnecessary spherical solder attached to a portion other than the suction hole is sucked into a suction nozzle. 2. The method for mounting a spherical solder according to claim 1, wherein the suction of the spherical solder is performed after applying an impact to a suction head. 3. A suction head having a plurality of suction holes formed therein, and a suction head having a suction port longer than the length from end to end of the suction hole at a position facing the suction head. A mounting device for a spherical solder, wherein a nozzle is provided and a suction nozzle or a suction head is movable in parallel at a facing position.