JP2001160674A - Ball mounting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ball mounting device with a structure that functions as a parallel fixing means between a ball suction face and a work, by making a work holding table suitably fitted to the ball suction face of a mounting head during ball mounting without a help of manufacturing accuracy or assembling accuracy of parts. SOLUTION: Firstly, the ball mounting device in this invention includes a ball feeding part, the work holding table, and the mounting head for sucking the ball and mounting the ball on the work held by the work holding table. Secondly, the work holding table includes a table to be fluctuated up and down and the table is supported by a flexible body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a ball mounting apparatus for mounting a solder ball, a solder bump, or the like on a work such as a wafer or a substrate, and more particularly, to a work holding table for holding a work. It is a ball mount device.

[0002]

2. Description of the Related Art When a large number of micro solder balls are mounted on a work such as a wafer or a substrate at the same time, parallelism between the solder ball suction surface of a mount head and the work is an important factor in order to secure mounting accuracy. Are known. Conventionally, the parallelism between the solder ball suction surface and the work has been ensured by the processing accuracy and the assembly accuracy of the components of the mount head and the work holding table.

[0003] However, in such accuracy securing means, the parallelism between the solder ball suction surface and the workpiece is disturbed by a temperature change in the installation room of the ball mounting device or a temperature change in the device due to the operation of the ball mounting device. This has been found to be a cause of defective mounting of a remaining ball, a displacement, a missing ball, and the like. In this case, the remaining ball means that the ball to be mounted on the work remains on the mount head, and the displacement means that the ball is mounted at a position shifted from the position where the work should be mounted. The missing ball means that the ball does not exist at the position where the workpiece should be mounted.

[0004]

According to the present invention, the means for securing the parallelism between the ball suction surface and the work does not rely only on the machining accuracy or assembly accuracy of the parts, but the work holding table is mounted on the mounting head when the ball is mounted. An object of the present invention is to solve the above-mentioned problem by adopting a structure that can follow the ball suction surface of the above.

[0005]

According to the present invention, a ball supply unit, a work holding table,
In a ball mounting device having a mounting head for adsorbing a ball from a ball supply unit and mounting the ball on a work held on a work holding table, the work holding table supports a vertically swingable table plate with an elastic body. It is an object of the present invention to provide a ball mount device characterized by the above.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. Although the solder ball mounting device in the embodiment has a wafer supply unit, a flux transfer unit, a ball mounting unit, and a work driving mechanism, the present invention is a solder ball mounting device having a feature in the ball mounting unit. . FIG. 1 is a front view schematically showing a ball mounting section of a solder ball mounting apparatus according to the present invention.

The ball mounting section includes a mount head 1 and a driving mechanism thereof, a ball supply section 2, a work holding table 3, and an excess ball removing device 4 disposed therebetween.
And a ball discharge device 6 that enters below the mount head 1 when a surplus ball is detected by the ball suction error inspection device 5.

A vacuum plate 8 serving as a ball suction surface is mounted on the lower surface of the mount head 1. The vacuum plate 8 is made of stainless steel having a thickness of about 0.1 mm and having a large number of suction holes for sucking solder balls by etching. In the embodiment, electrolytic polishing is performed in order to prevent the solder ball from being damaged at the end of the suction hole.

The inside of the mount head 1 is exhausted from an exhaust port by a blower motor (not shown), the pressure is reduced, and a vacuum pressure is generated in each of the suction holes of the vacuum plate. To be absorbed.

The mount head 1 is provided with a two-axis drive mechanism, a Y-axis reciprocating between the ball supply unit 2 and the work holding table 3, and a Z-axis vertically moving up and down. 9 is a Z-axis drive motor, and 10 is a Y-axis drive motor.

The drive mechanism for the Y axis here is used for positioning the mount head 1 and a work, as well as for the role of moving the mount head 1. The Z-axis drive mechanism is set so that the lower surface of the mount head 1 comes into contact with the wafer during mounting, and stops lowering when the load detected by a load sensor (not shown) reaches a preset set value.

The ball supply unit 2 has a configuration like a parts feeder. A vibrator is attached to a ball tray 7 for supplying solder balls to the mount head 1. The vibration of the vibrator causes the solder ball to jump up obliquely upward, and when viewed from above, the solder ball moves around the ball tray 7.

Above the ball tray 7, a supply port for supplying solder balls from the ball stocker (not shown) into the ball tray 7 is disposed so as to be able to advance and retreat. A sensor for detecting the remaining amount of the ball in the ball tray 7 is attached to the tip of the supply port, and when the remaining amount of the ball is detected, a fixed amount of the solder ball is supplied from the ball stocker. The supply port is structured to be retracted outside the ball tray 7 in order to avoid interference with the mount head 1 when the solder ball is attracted.

The surplus ball removing device 4 is a removing nozzle for removing excess balls adsorbed on the mount head 1. The ball suction error inspection device 5 has four lines C
Mistakes such as missing balls and extra balls (excess balls) of the mount head 1 caused by the CD camera
Detects a remaining ball that is incorrectly mounted. In this case, the missing ball means that there is no ball at the position where the mount head 1 is to be sucked, and the extra ball means that a plurality of balls are mounted on one suction hole of the mount head 1 or that the suction hole The ball is attached to a position other than the above, and the term "remaining ball" means that the ball to be mounted on the work remains on the mount head.

The work holding table 3 urges a table plate 11 for sucking and holding a wafer 16 as a work upward by a compression spring 12 from below, and the upper limit position is determined by a plate retainer 13. I have. That is, as shown in the drawing on the right side of FIG. 2, a stop flange 17 is formed on the lower surface side of the table plate 11 toward the outside, and the plate holder 13 has a diameter larger than that of the wafer holding surface of the table plate 11. It is formed in a ring shape with a smaller diameter inner peripheral surface, and
The compression spring 12
And the stop flange 17 abuts on the plate retainer 13 to limit the upper limit position.

In the embodiment shown, one compression spring 1 is provided at the center.
Although two compression springs 12 are provided, the number of the compression springs 12 is not limited to one, and several compression springs 12 may be provided around the periphery. Further, the compression spring 12 may be any as long as the table plate 11 can swing up and down in accordance with the vacuum plate 8 of the mount head 1, and another elastic body can be used.

The outer peripheral surface 14 of the table plate 11 excluding the stop flange 17 is spherical, and the inner peripheral surface of the plate retainer 13 is cylindrical. For this reason, even if the table plate 11 is inclined following the vacuum plate 8, the diameter in the horizontal direction where the outer peripheral surface 14 of the table plate 11 is in contact with the plate retainer 13 does not change.
Outer peripheral surface 14 of table plate 11 and plate holder 1
3 is always slidable by line contact. Therefore, even when the table plate 11 is inclined, the table plate 11 and the plate retainer 13 do not fall off or shift in the horizontal direction.
There is no horizontal displacement between the mounting plate 1 and the vacuum plate 8 of the mount head 1. Although the outer peripheral surface 14 of the table plate 11 is a spherical surface in the embodiment, the outer peripheral surface 14 of the table plate 11 and the plate holder 13
The shape is not limited to a spherical surface as long as the inner peripheral surface can slide in line contact. The table plate 11 is provided with a rotation preventing mechanism 18 for the plate holder 13 as shown in the left side drawing of FIG.

The table plate 11 is provided with a wafer suction hole 15. The wafer suction hole 1 on the upper surface of the table plate 11 is passed through a blower motor (not shown).
Vacuum suction is started from 5 and the wafer 16 can be suction-held on the table plate 11.

Hereinafter, the operation steps of the solder ball mounting device will be described. First, a robot supplies wafers to the work holding table 3 one by one from a wafer cassette for supply. The work holding table 3 moves to the flux supply unit, transfers the flux to the wafer 16, and moves to the ball mounting position.

On the other hand, the mount head 1 descends from above the ball supply unit 2 and stops at a specified position to suck the solder ball. When the internal pressure of the mount head 1 becomes lower than the predetermined pressure, it is determined that the suction is completed, and the mount head 1 is raised. After that, the surplus balls are removed by the surplus ball removing device 4 and moved to the ball suction error inspection device 5.

When there is a ball suction error, if the ball is a missing ball or an extra ball, the ball is moved to the ball supply unit 2 again and the suction operation is repeated. When extra balls are continuously present, the ball discharging device 6 enters below the mount head 1, discharges all the suction balls into the ball discharging device 6, moves to the ball supply unit 2 again, and performs the suction operation. repeat.

If there is no abnormality, the mount head 1 moves to the ball mounting position. At the ball mounting position, the positioning is performed by recognizing the alignment mark on the lower surface of the mount head 1 with a CCD camera provided on the work holding table 3. After the positioning, the mount head 1 descends, the lower surface of the mount head 1 comes into contact with the wafer 16, and stops descending when the load detected by a load sensor (not shown) reaches a preset value.

When the mount head 1 descends while the solder balls are being sucked and reaches the set value of the load sensor from the point of contact with the wafer 16, the descending is stopped. The table plate 11 can be moved down following the vacuum plate 8 which is the ball suction surface of the mount head 1 by the amount of descent of the mount head 1 from the time of contact of the mount head 1 to the stop of descent, so that the degree of parallelism can be corrected.

At this point, the solder balls are sandwiched between the mount head 1 and the wafer 16. Here, when the suction valve is switched to release the pressure in the mount head 1 to the atmospheric pressure, the solder balls are surely separated from the mount head 1 and mounted on the wafer 16. The mount head 1 then rises.

After the mounting of the solder balls is completed, the work holding table 3 returns to the wafer supply unit, and the state of mounting the solder balls on the wafer is inspected by a CCD camera on the way. As a result of the inspection, the robot is inserted into the unloading wafer cassette if the mount is good and into the defective wafer cassette if the mount is bad.

[0026]

According to the present invention, in the ball mounting apparatus, since the work holding table supports a vertically oscillating table plate by an elastic body, the means for securing the parallelism between the ball suction surface and the wafer is a component. The work holding table follows the ball suction surface of the mount head to ensure parallelism without relying only on the processing accuracy and assembly accuracy of the components. Not only do not need to make any request, but also it is not necessary to worry about severe indoor temperature control and changes in the internal temperature due to operation. That is, the ball mount device does not make a mounting mistake on the work due to a change in the room temperature or the temperature inside the device.

According to the second aspect of the present invention, there is provided a plate pressing means on the outer periphery of the table plate for restricting the elevation of the table plate, and the outer peripheral surface of the table plate and the inner peripheral surface of the plate pressing means are brought into line contact with each other. Since it is slidable, a smooth copying operation can be ensured.

[Brief description of the drawings]

FIG. 1 is a schematic front view of a mounting portion of a solder ball mounting device.

FIG. 2 is a side sectional view of a work holding table.

FIG. 3 is a plan view of the same.

[Explanation of symbols]

 1. . . . . . . . Mount head 2. . . . . . . . Ball supply unit 3. . . . . . . . Work holding table 4. . . . . . . . Excess ball removal device 5. . . . . . . . 5. Ball suction error inspection device . . . . . . . Ball discharging device 7. . . . . . . . Ball tray 8. . . . . . . . Vacuum plate 9. . . . . . . . 9. Z-axis drive motor . . . . . . 10. Y-axis drive motor . . . . . . Table plate 12. . . . . . . Compression spring 13. . . . . . . Plate holder 14. . . . . . . Outer peripheral surface 15. . . . . . . Wafer suction hole 16. . . . . . . Wafer 17. . . . . . . Stop collar 18. . . . . . . Non-rotating mechanism

Claims (3)

[Claims] 1. A ball supply unit, a work holding table,
In a ball mounting device having a mounting head for adsorbing a ball from a ball supply unit and mounting the ball on a work held on a work holding table, the work holding table supports a vertically swingable table plate with an elastic body. A ball mount device characterized in that: 2. The apparatus according to claim 1, further comprising plate holding means on the outer periphery of the table plate for restricting the rise of the table plate, wherein the outer peripheral surface of the table plate and the inner peripheral surface of the plate holding means can be slid by linear contact. The ball mounting device according to claim 1, wherein 3. The ball mounting device according to claim 1, wherein the shape of the table plate is circular.