JPH10242630A - Method of loading solder ball, and its device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a solder ball from being loaded in an unnecessary place by loading the solder ball in the solder bump formation part of a multifunction device, after sucking the solder ball with a downward suction head where a through hole is board in a place which becomes the position of face symmetry with the solder bump formation place of a device. SOLUTION: In an upward suction head 2, a through hole 9 is bored in the same position as the solder bump formation place of a multifunction device, and a solder ball B is dropped into the groove 10 of the through hole 9, and at the same time, the solder ball B dropped in the groove 10 is retained by sucking it from the through hole 9. Then, the solder balls lying in a place other than the groove 10 are eliminated to the place other than the upward suction head 2 by blowing the topside of the upward suction head 2 with a jet nozzle 15. Next, the downward suction head 3 is brought close to the upward suction head 2, and corresponding through holes 9 and 18 are severally accorded with each other. This way, the solder ball B is loaded in the solder bump loading place, being suck by the through hole 18 of the downward suction head 3.

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 minute solder balls on a substrate or a semiconductor element of an electronic component.

[0002]

2. Description of the Related Art In recent years, electronic devices have become smaller and lighter with higher functionality. For this reason, electronic components used in such electronic devices are also required to be reduced in size and multifunctional. A long ago ago, multifunctional electronic components such as SOP and QFP had a large number of leads on both sides or four sides of the package. However, when a lead is provided on the side surface, the number of leads to be provided is determined by the size of the side surface, and further multifunctionality cannot be expected.

[0003] Recently, electronic components such as BGA and CSP (hereinafter, referred to as multifunctional devices) which have been made smaller and more multifunctional have been used.
These multifunctional devices have a large number of electrodes formed in a grid on the back surface of a substrate on which a semiconductor element is mounted. When mounting a multi-function device on a printed circuit board,
The electrodes of the multifunction device and the lands of the printed circuit board are joined by solder.

In general, in soldering an electronic component and a printed circuit board, soldering is performed while separately supplying solder. However, in a multifunctional device, there are too many electrodes, and furthermore, a soldering portion is formed between the printed circuit board and the multifunctional device. Since there is a gap between them, soldering while supplying solder separately during soldering not only results in poor productivity, but also makes it difficult to completely apply the solder to all the electrodes. Occurs.

[0005] Therefore, in a multifunctional device, solder bumps to which solder is previously adhered are formed on the electrodes of the substrate,
When soldering a multifunctional device and a printed circuit board, soldering is performed with the solder bumps.

[0006] Solder balls are used for forming solder bumps of this multifunctional device. Solder balls are adsorbed to a suction head with a through hole with a smaller diameter than the solder ball at the position symmetrical to the solder bump formation point and moved to a multi-function device, and the solder ball is mounted on the solder bump Was to do.

[0007] Conventional solder ball mounting methods include:
There were a floating method, a pin nozzle adsorption method, a vibration method rotation method, and the like.

In the floating method, the suction head is put on a container containing a large number of solder balls, and gas is blown out from the lower part of the container to float the solder balls in the container.
In this method, the solder balls floating in the container are sucked into the through holes by sucking gas from the through holes of the suction head. (Reference: JP-A-4-65130, 7)
-122801, 8-153958, 8-2-2649
No. 30)

The pin nozzle suction method is a method in which a cylindrical pin is installed in a through hole of a suction head, the pin is inserted into a container, and a solder ball is sucked to the tip of the pin. (Reference: JP-A-7-202400, 7
307340, 8-66766)

[0010] The vibration method is a method in which a container containing solder balls is vibrated, and the solder balls moving in the container are sucked by a suction head. (Reference: JP-A-8-16)
2493, 8-162494 and 8-162495)

[0011] The rotation method is to cover the container containing the solder balls with a suction head, rotate the container and the suction head together, and place the solder ball on the suction surface when the through hole faces upward. This is a method in which a solder ball is sometimes adsorbed to a through hole. (Reference: JP-A-8-2559)
No. 97)

[0012]

In the conventional solder ball mounting method described above, though the solder ball is sucked from below with the through hole of the suction head facing downward, the solder ball is attached to an unnecessary portion other than the through hole. Solder balls sometimes adhered. Therefore, the solder ball adhered to an unnecessary portion of the suction head is carried to the multifunctional device as it is, and the solder ball is mounted at a place other than the solder bump forming portion, and a short circuit or insulation failure often occurs.

If the through-hole of the suction head is downward, the solder ball should drop downward due to the weight of the solder ball itself in portions other than the through-hole where suction is performed. Is also attached to the part. The inventor of the present invention has made intensive studies on the cause of the solder ball adhering to portions other than the downward through hole of the suction head, and as a result, it has been found that the cause is that the solder ball is charged with static electricity. In other words, the diameter of a solder ball used for a multifunctional device is 1 mm or less (currently, the diameter is 0.3 mm or less).
Since it has a small diameter of 76 mm), it is light in weight and easily adheres to the suction head even with a small amount of electrostatic charge. Recently, the diameter of solder balls is 0.3mm, 0.2
mm, 0.1 mm
More adhesion to unnecessary parts of the suction head has occurred.

When the suction head is used in the method of mounting the solder balls, it is considered that if the number of solder balls around the suction head is reduced, the number of solder balls adhering to portions other than the through holes of the suction head is also reduced. JP-A-8-2
Japanese Patent No. 64930 proposes to use a small amount of solder balls. In this method, first, a tray provided with a larger number of through holes than the number of solder balls mounted on an electronic component is placed so that the through holes face upward, and the solder balls are sucked into the through holes, and other than the through holes, Use a squeegee to remove the solder balls in the area. Next, the suction head having a through hole formed at a position symmetrical with the solder bump forming portion of the electronic component is placed downward and slightly away from the tray. Then, a gas is blown out from the through hole of the suction head to float the solder ball in the through hole of the tray, and the floating solder ball is sucked by the through hole of the suction head. In the method using this small amount of solder balls, the number of solder balls to be attracted to the tray is larger than the number of solder balls to be mounted on the multi-function device. Will adhere to the surface.

It is an object of the present invention to provide a solder ball mounting method and a solder ball mounting method in which a solder ball is never mounted except at a solder bump forming portion of a multifunctional device even if the solder ball is charged with static electricity.

[0016]

The inventor of the present invention sets the number of solder balls to be sucked into the through-holes of the suction head to be equal to the number of solder bumps formed in the multifunctional device so that the through-holes of the suction head face downward (downward). Suction head),
If all of the solder balls can be completely sucked into the through holes of the downward suction head, the solder balls will never adhere to the places other than the through holes, and the through holes have the same number of suction heads as the downward suction head. The present invention focuses on the fact that a predetermined number of solder balls can always be secured if the solder balls are once sucked by the upward suction head so that the solder balls are directed upward (referred to as an upward suction head) and then transferred to the downward suction head. Completed.

According to the present invention, a solder ball is arranged at a position corresponding to a solder bump forming portion of a multifunctional device, and a through hole is formed in the solder ball at a position symmetrical with the solder bump forming portion of the device. And mounting the solder ball on the solder bump forming portion of the multi-function device after suction by the downward suction head.

Another aspect of the present invention is to provide a multifunctional device, in which a through hole is formed at a position corresponding to a solder bump forming position, and a large number of solders are placed on an upward suction head having a groove at the top of the through hole. Placing the ball and sucking the solder ball in the groove into the through-hole; removing the solder ball outside the groove of the upward suction head out of the upward suction head; through-hole and surface of the upward suction head A downward suction head having a through hole formed in a symmetric position is brought into close contact with the upward suction head such that the corresponding through holes of the upward head and the downward head coincide with each other, and gas is discharged from the through hole of the upward suction head. A step of sucking out the solder balls of the upward suction head to the downward suction head by blowing out and sucking through the through holes of the downward suction head. A method of mounting the solder balls, characterized in that it consists of; the solder ball is moved downward suction head adsorbed multifunctional device, the solder balls step of mounting the solder bump forming portions of multifunction devices.

Still another aspect of the present invention is that a main body is provided with an inclined portion between a large-diameter hollow portion at an upper portion and a small-diameter sliding portion at a lower portion. An upward suction head with a through hole at the same position is installed slidably in the vertical direction, and a stirrer that can move the solder balls irregularly is installed in the hollow part, and At the top dead center of the suction head, an elimination device that eliminates unnecessary solder balls riding on the upward suction head outside the upward suction head is installed.Further, above the upward suction head, a through hole of the upward suction head is provided. A solder ball mounting device, characterized in that a downward head having a through hole formed at a plane-symmetric position is movably installed.

[0020]

In the method of mounting solder balls according to the present invention, the same number of solder balls as the number of solder bumps of a multi-function device are arranged in advance at locations where the solder bumps are formed on the multi-function device. If all the solder balls are sucked by the suction head, unnecessary solder balls do not adhere to the suction head. To place the required number of solder balls in a predetermined position, place them on a suction head that has through holes at locations that match the solder bump formation locations of the multi-function device. Or move to unnecessary parts.

In the step of mounting the solder ball sucked on the downward suction head of the mounting method of the present invention on a multi-function device, a spacer may be installed in a portion other than the solder bump formation portion between the downward suction head and the multi-function device. Since the downward suction head does not fall below the thickness of the spacer, the solder ball is not excessively deformed by being pressed or pushed into the through hole.

The through hole of the suction head used in the mounting apparatus of the present invention is naturally smaller than the diameter of the solder ball, but must have a diameter that can sufficiently hold the solder ball during suction. A groove for accommodating one solder ball is formed in the through hole of the upward suction head.

The stirrer used in the solder ball mounting device of the present invention is a device which moves the solder balls in the main body at random, thereby moving the solder balls uniformly on the upward suction head to thereby make all the grooves which have not penetrated. A solder ball can be made to invade the inside. As a stirrer for moving the solder balls, a means for randomly discharging gas is suitable, but it goes without saying that mechanical means for vibrating or tilting the main body can also be employed.

Further, as a device for discharging unnecessary solder balls on the upward suction head reaching the top dead center,
An ejection nozzle for ejecting compressed gas or an electrostatic brush is suitable. When the electrostatic charge is so large that the ejection nozzle cannot be eliminated, the electrostatic brush is effective.

If a guide device such as a guide pin and a guide hole is provided on the upward suction head and the downward suction head of the solder ball mounting device of the present invention, respectively, when the upward suction head and the downward suction head are brought into close contact with each other. ,
Since the suction head moves along the guide device, each corresponding through-hole can be accurately matched.

[0026]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG.
6 to 6 are views for explaining a method of mounting a solder ball according to the present invention,
7 to 10 are views for explaining the operating state of the solder ball mounting device of the present invention.

First, a method of mounting a solder ball will be described. In the solder ball mounting method of the present invention, as shown in FIG. 3, an upward suction head 2 having a through hole on the upper side and a downward suction head 3 having a through hole 18 on the lower side are used. A through hole 9 is formed in the upward suction head 2 at the same position as a solder bump forming position of a multi-function device on which a solder ball B is mounted, and a groove capable of accommodating one solder ball is provided above the through hole. 10 are formed. The downward suction head 3 is provided with a through hole 18 at a position symmetrical with the upward suction head 2 in plane.

For example, if the diameter of the solder ball is 0.3 mm and the diameter of the through hole is 0.1 mm, the size of the groove is 0.4 mm in diameter and 0.4 mm in depth. 0.3 mm is appropriate.

First, a large number of solder balls B are placed on the upward suction head 2 as shown in FIG.
Solder ball B dropped into groove 10 at the same time as it was dropped into groove 10 by suction through through hole 9
Hold.

Then, as shown in FIG. 2, the upper surface of the upward suction head 2 is blown by the ejection nozzle 15 or scratched by the electrostatic brush 14 so that the solder balls B other than the grooves 10 are removed to a place other than the upward suction head 2. I do.

Next, as shown in FIG.
Is brought into close contact with the upward suction head 2. At this time, the corresponding through holes 9 and 18 of the upward suction head 2 and the downward suction head 3 are aligned. If the upward suction head 2 and the downward suction head 3 are in close contact, the upward suction head 2
At the same time, the gas is blown out from the through hole 9 and is sucked from the through hole 18 of the downward suction head 3.

When the close contact between the upward suction head and the downward suction head is released and the two are separated, the solder balls B are sucked into the through holes 18 of the downward suction head 3 as shown in FIG.

The downward suction head that has absorbed the solder ball B is moved to the multifunctional device D as shown in FIG. 5, and the solder ball B is brought into contact with the solder bump mounting location M. Adhesive flux F is applied to solder bump mounting portion M in advance, and a little gas is blown out from through-hole 18 to remove solder ball B from the through-hole. At this time, when the spacer S having the opening where the solder bump is formed is placed on the multifunctional device D between the multifunctional device and the downward suction head so that the opening becomes the solder bump forming portion, the solder ball is pressed more than necessary. Therefore, it is not deformed or pushed into the through hole.

Thereafter, as shown in FIG. 6, when the downward suction head is moved, the solder ball B is mounted on the solder bump forming portion M of the multifunctional device. After the solder balls are mounted, the multifunctional vise is heated by a heating device such as a reflow furnace, and the solder balls are welded to the multifunctional device.

Next, another embodiment of the solder ball mounting apparatus will be described.

The solder ball mounting device of the present invention comprises a main body 1, an upward suction head 2, a downward suction head 3, a stirring device 4, and a removal device 5.

The main body 1 has a sliding portion 6 having a small diameter at a lower portion, a hollow portion 7 having a large diameter at an upper portion, and an inclined portion 8 between the sliding portion 6 and the hollow portion 7. The upward suction head 2 is installed in the sliding portion 6 so as to be slidable in the vertical direction and stopped at a predetermined high position (top dead center) and a low position (bottom dead center). The upward suction head has a through hole 9 formed at the same position as the solder bump mounting position of the multi-function device as described in the solder ball mounting method described above, and the solder ball can be stored above the through hole. The groove 10 is formed.
The through hole is smaller than the diameter of the solder ball, and the groove is large enough to accommodate only one solder ball.

The stirrer 4 is installed in the cavity 7. The stirrer according to the present invention moves the solder balls in the cavity 7 irregularly. In the embodiment, the cylindrical porous metal 11 is fitted into the wall of the cavity 7. The porous metal 11 is connected to a gas supply pipe 12 passing through one side of the main body and leading to the outside, and an exhaust pipe 13 passing through the other side and leading to the outside. When a gas such as compressed nitrogen gas is supplied from the supply pipe, nitrogen gas flows out of the porous metal 11 into the hollow portion 7 at random, so that the solder balls B in the hollow portion move in all directions. Become. The gas flowing into the cavity 7 is discharged to the outside from the exhaust pipe 13 through the porous metal on the other side.

In the cavity 7, an exclusion device 5 is provided. The removing device removes unnecessary solder balls on the upper surface of the upward suction head 2 to a place other than the upward suction head when the upward suction head 2 is at the position of the top dead center. The convenient removing device used in the present invention includes the electrostatic brush 14 and the ejection nozzle 15.

The upper part of the main body 1 is formed with a hole 16 having a diameter slightly larger than the diameter of the downward suction head 2, and a lid member 17 for opening and closing the hole is slidably provided on the hole. .

Above the lid member 17, the downward suction head 3 is installed so as to be movable in all directions such as up, down, front, back, left and right. The downward suction head 3 is provided with a through hole 18 at a position symmetrical with the upward suction head 2 in plane. When the downward suction head 3 descends into the hollow portion 7 of the main body 1, it descends so that the through holes 18 of the downward suction head 3 coincide with the corresponding through holes 9 of the upward suction head 2.

Guide devices are provided for the upward suction head and the downward suction head. The guide device is a guide pin 19 protruding from the peripheral edge of the upward suction head 2 and a guide hole 20 formed in the peripheral edge of the downward suction head 3. When the upward suction head and the downward suction head are brought into close contact with each other, the corresponding through-holes of the guide pins and the guide holes are accurately matched.

Next, the operating state of the solder ball mounting apparatus having the above-described configuration will be described.

At the beginning of the operation of the mounting device, as shown in FIG. 7, the upper hole 16 of the main body 1 is covered with a cover member 17, and the downward suction head 2 is at a lower dead point slightly below the inclined portion 8. Stopped at. Solder balls B, which are considerably larger than the number mounted on the multi-function device, are inserted into the main body 1. Here, the through-hole 9 of the upward suction head 2 is kept in a suction state, and nitrogen gas is sent from the gas supply pipe 12 to the porous metal 11 which is a stirring device. Then, the nitrogen gas flowing out of the porous metal 11 flows randomly in the main body 1, and moves the solder balls B evenly on the upward suction head 2 so as to enter all the grooves 10. The solder ball B that has entered the groove 10 stays in the groove by the suction of the through hole 9.

When the solder balls B have entered all the grooves 10 in this way, the supply of the nitrogen gas from the gas supply pipe 12 is stopped. At this time, in the upward suction head 2, the solder balls B enter all the grooves 10, and the solder balls B ride on the other portions than the grooves. If the solder balls other than the grooves are charged with static electricity, they will strongly adhere to the suction head. As shown in FIG. 8, the upward suction head 2 is raised and stopped at the top dead center. Then, nitrogen gas is ejected from the ejection nozzle 15 serving as an expulsion device to blow off the solder ball riding on the portion other than the groove 10 of the upward suction head 2 out of the upward suction head. Is scraped off with an electrostatic brush 14. The solder balls dropped out of the upward suction head by the ejection nozzle or the electrostatic brush in this way accumulate on the inclined portion 8.

When the solder balls B enter all the grooves 10 of the upward suction head 2 and the solder balls existing outside the grooves are eliminated, the lid member 17 is opened. At this time, the upper surface of the upward suction head is photographed with a television camera (not shown) from the top of the main unit, and the upper surface of the upward suction head is image-processed. To the point and repeat the work of inserting the solder ball into the groove.

When the solder balls are stored in all the grooves in the image processing, the downward suction head 3 which has been waiting above is lowered, and the upward suction head 2 and the downward suction head 3 as shown in FIG. Corresponding through holes 9, 18
Are brought into close contact with each other. Then, the nitrogen gas is blown out from the through hole 9 of the upward suction head 2 and is simultaneously sucked from the through hole 18 of the downward suction head 3.
Then, the solder balls B contained in all the grooves 10 of the upward suction head 2 are sucked into the through holes of the downward suction head 3.

When the solder balls B are sucked into the through holes 18 of the downward suction head 3, the downward suction head 3 is raised as shown in FIG. At this time as well, if the suction surface of the downward suction head is image-processed and the solder balls are not sucked in all the through holes, the operation of sucking the solder balls to the downward suction head is performed again as described above. When the solder ball is adsorbed in all the through holes of the downward suction head by the image processing, the downward suction head is moved to the multifunctional device and mounted on the solder bump forming portion of the multifunctional device.

Using the above solder ball mounting apparatus of the present invention, 0.1 mm solder balls were mounted on 100 BGA substrates on which 358 electrodes were formed in a grid at intervals of 0.25 mm. Nothing was mounted in unnecessary places or not mounted.

[0050]

According to the present invention, the same number of solder balls as the solder ball mounting portions of the multifunctional device are arranged, and only the solder balls are sucked by the through holes of the downward suction head. Even if static electricity is charged, unnecessary solder balls are not mounted on the multi-function device at all.In addition, since the required number of solder balls is once absorbed by the upward suction head, it is subject to some mechanical vibration. In addition, the solder ball does not move even if blown by flowing gas, and the solder ball is not mounted.

[Brief description of the drawings]

FIG. 1 shows a state where a solder ball is placed on an upward suction head.

FIG. 2 shows a state in which a solder ball at an unnecessary portion of the upward suction head is removed.

FIG. 3 shows a state in which an upward suction head and a downward suction head are in close contact with each other.

FIG. 4 shows a state in which a solder ball is sucked by a downward suction head.

FIG. 5 shows a state where the solder ball sucked by the downward suction head is mounted on the multifunctional device.

FIG. 6 shows a state in which a solder ball is mounted on a multifunctional device.

FIG. 7 is a front sectional view showing a state where a solder ball is placed on an upward suction head in the mounting apparatus of the present invention.

FIG. 8 is a front sectional view of the mounting apparatus of the present invention in a state where unnecessary solder balls on an upward suction head are removed.

FIG. 9 is a front sectional view showing a state where the upward suction head and the downward suction head are closely attached to each other in the mounting apparatus of the present invention.

FIG. 10 is a front sectional view showing a state where a solder ball is sucked to a downward suction head in the mounting apparatus of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main body 2 Downward suction head 3 Upward suction head 4 Stirrer 5 Elimination device 6 Sliding part 7 Cavity part 8 Inclined part 9, 18 Through hole 10 Groove 14 Electrostatic brush 15 Injection nozzle B Solder ball

Claims (9)

[Claims] 1. A solder ball is disposed at a position corresponding to a solder bump forming portion of a multifunctional device, and the solder ball is directed downward with a through hole formed at a plane symmetrical position with the solder bump forming portion of the device. A method for mounting a solder ball, comprising: mounting a solder ball on a solder bump forming portion of a multi-function device after suction by a suction head. 2. A through hole is formed at a position corresponding to a solder bump forming portion of a multifunctional device, and a large number of solder balls are placed on an upward suction head having an upper portion of the through hole as a groove, and the solder ball is placed in the groove. Adsorbing the solder balls into the through holes; removing the solder balls outside the grooves of the upward suction head out of the upward suction head; and forming through holes at positions symmetrical to the through holes of the upward suction head. The perforated downward suction head is brought into close contact with the upward suction head such that the corresponding through-holes of the upward head and the downward head coincide with each other, and the gas is blown out from the through-hole of the upward suction head, and the downward suction is performed. Suctioning the solder ball of the upward suction head to the downward suction head by sucking through the through hole of the head; Moving the downward suction head to the multi-function device and mounting the solder ball on the solder bump formation portion of the multi-function device. 3. The method according to claim 2, wherein in the step of mounting the solder balls adsorbed on the downward suction head on the multifunctional device, a spacer is installed between the downward suction head and the multifunctional device. How to mount solder balls. 4. An inclined portion is formed between a large-diameter hollow portion and a small-diameter sliding portion at a lower portion of the main body, and a through-hole is formed in the sliding portion at the same position as a solder bump forming portion of the multifunctional device. An upward suction head with a hole is installed slidably in the vertical direction, and a stirring device that can move the solder ball irregularly is installed in the cavity,
At the top dead center of the upward suction head, an elimination device for removing unnecessary solder balls riding on the upward suction head to the outside of the upward suction head is installed, and a through hole of the upward suction head is provided above the upward suction head. A solder ball mounting device, characterized in that a downward suction head having a through hole formed at a position symmetrical to the plane is movably installed. 5. The solder ball mounting device according to claim 4, wherein a groove for accommodating one solder ball is formed in an upper portion of the through hole of the upward suction head. 6. The solder ball mounting device according to claim 4, wherein the stirring device is a gas blowing device. 7. The solder ball mounting device according to claim 4, wherein said removing device is an electrostatic brush. 8. The solder ball mounting device according to claim 4, wherein said removing device is a jet nozzle for jetting a compressed gas. 9. The solder ball mounting device according to claim 4, wherein a guide device is provided on each of the upward suction head and the downward suction head.