JP2001015898A - Mount head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the mounting head of a ball mounting device which is capable of mounting a large number of balls accurately on a work by a method wherein the work and a vacuum plate are ensured of parallelism. SOLUTION: A vacuum plate 40 provided with a large number of suction holes 46 to suck up balls is provided in the mounting head 26 of a ball mounting device so as to ensure a work and a vacuum plate 40 of parallelism. Furthermore, a support plate 41 which is equipped with gas communicating paths 51 that are not corresponding to the chucking holes 4 of the vacuum plate 40 and supports the vacuum plate 40 from an external force. A gas-permeable gas communicating member which includes a vacuum plate chucking region is arranged between the vacuum plate and the support plate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a mounting head used in a ball mounting apparatus for mounting a solder ball, a solder bump, or the like on a wafer or a substrate.

[0002]

2. Description of the Related Art In a conventional solder ball mounting apparatus, a mounting head for sucking and sucking solder balls is provided with a plurality of suction holes for sucking solder balls on a vacuum plate located on a lower surface, and the inside of the mounting head is vacuumed. Then, the solder ball is sucked and sucked into the suction hole, moved onto the work, and mounted on the work.

When a solder ball or the like is mounted on a work with a mount head, maintaining the parallelism between the vacuum plate and the work correctly has been an essential condition for accurate mounting of the solder ball and the like. In particular, when mounting a large amount of solder balls or the like on a work, it is important to secure the parallelism. However, due to the thinning of the vacuum plate and the like, the distortion of the vacuum plate has increased, and it has become difficult to maintain the parallelism between the vacuum plate and the work correctly.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a mounting head of a ball mounting apparatus capable of accurately mounting a large amount of solder balls on a work by ensuring parallelism between the work and a vacuum plate. It is intended for.

[0005]

A first aspect of the present invention is to secure the strength of the vacuum plate side as means for securing the parallelism between the workpiece and the vacuum plate. A vacuum plate having suction holes, a support plate having a gas passage not corresponding to the suction holes of the vacuum plate and supporting the vacuum plate from an external force, and a suction area of the vacuum plate between the vacuum plate and the support plate. The present invention provides a mount head in a ball mount device, comprising: a gas-permeable member having gas permeability disposed therein.

The second invention focuses on eliminating the influence of the work on the vacuum plate and coping with distortion of the work as means for securing the parallelism between the work and the vacuum plate. outside,
It is an object of the present invention to provide a mount head in a ball mount device, wherein a spacer having a thickness corresponding to the diameter of a suction ball is formed so as to protrude downward from the mount head.

A third invention is a combination of the first invention and the second invention, and aims to provide a mount head in a ball mount device capable of ensuring a more complete parallelism between a work and a vacuum plate. Is what you do.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of a solder ball mounting device shown in one embodiment. The solder ball mounting device includes a wafer supply unit 1, a flux transfer unit 2, a ball mount unit 3, and a work driving mechanism 4. Mount head 2 according to the present invention
5 is present in the ball mount 3.

The wafer supply unit 1 includes a wafer cassette 5 for supply, a wafer cassette 6 for unloading, a wafer cassette 7 for defective wafers, and a scalar robot 9 for clean room for transferring wafers 49. And the wafer positioning position 8 on the work drive mechanism 4.

As shown in FIG. 2, two CCD cameras 31 are arranged above the wafer positioning position 8 so as to overlap each other in the drawing (only one front camera is shown in the drawing). ), An illuminator 32 facing the wafer 49 is provided below the illuminator 32. CCD camera 31
Is movable by a motor 33 in a direction (X-axis direction) parallel to the work drive mechanism 4 above the wafer positioning position 8 on the work drive mechanism 4.

The work drive mechanism 4 includes a wafer stage 3
0 is provided, and a two-axis drive mechanism for driving the wafer stage 30 is provided, that is, an X-axis (left-right direction in FIG. 1) and a Θ-axis (rotation direction). The Θ-axis drive mechanism is a drive mechanism whose main role is positioning, while the X-axis drive mechanism has a role of moving the work and a role of positioning.

The wafer stage 30 is moved by an X-axis drive mechanism to a wafer positioning position 8 and a flux transfer position 11.
And the movement between the ball mounting positions 20 can be stopped. The wafer stage 30 is provided with two CCD cameras 23 and 23 'for observing the transfer head 13 and the mount head 25.

The flux transfer section 2 includes a transfer head 13 and a drive mechanism thereof, a flux supply device 10, and a flux transfer position 11 on a work drive mechanism 4. A part 12 is provided.

The transfer head 13 of the flux supply device 10
As shown in FIG. 3, the flux supply device 10
There is provided a two-axis drive mechanism of a Y-axis and a Z-axis (elevation axis) which reciprocate between the flux transfer position 11 on the work drive mechanism 4 and the flux transfer position 11. In the figure, reference numeral 34 denotes a Z-axis drive motor of the transfer head 13, and reference numeral 34 'denotes a Y-axis drive motor. The Y-axis driving mechanism here is used for positioning the transfer head 13 and the work together with the role of the transfer head 13 to move.

The flux supply device 10 is provided with a flat flux leveling portion, and the squeegee 15 can level the flux to a constant thickness. A flux supply section 16 corresponding to the flux transfer area of the transfer head 13 is formed in the flux leveling section.

The ball mounting section 3 includes a mounting head 2
5 and its driving mechanism, a ball supply device 19, a ball mounting position 20 on the work driving mechanism 4, an excess ball removing device 21 disposed therebetween, a ball suction error inspection device, and a ball suction error inspection device. And a ball discharge device 24 that enters below the mount head 25 when an excess ball is detected.

The features of the present invention appear in the mount head 25. Mount heads 25, 26, 26 'according to the present invention
There are three types. The first mount head 26
As shown in FIGS. 5 and 6, on the lower surface of the mount head 26, a punching metal 43 serving as a support plate in the present invention, a support plate 41 formed of a fine mesh serving as a gas conducting member in the present invention, and a solder Ball 4
7, a vacuum plate 40 provided with fine suction holes 46 for suction is integrally attached by a plate holder 44. The vacuum plate 40 and the support plate 41 are held in a free state with a certain gap between the plate holders 44.

As shown in FIGS. 5 and 6, the punching metal 43 is provided with suction holes 46 of the vacuum plate 40.
And a gas passage 51 having a hole diameter of 3.8 mm and a pitch of 5 mm. The punching metal 43 supports the support plate 41 from an external force.
This prevents bending of the vacuum plate 40 due to zero bending and reaction force from the wafer 49. Instead of the punching metal 43, a supporting member having a honeycomb structure may be used.

The vacuum plate 40 is formed by etching solder balls 47 of stainless steel having a thickness of 0.1 mm by etching.
Is used in which a large number of suction holes 46 for opening the suction holes are formed. In the embodiment, resin coating is performed to prevent the solder ball 47 from being damaged at the end of the suction hole 46.

The support plate 41 is disposed between the vacuum plate 40 and the punching metal 43, as shown in FIGS. Support plate 41
Is formed by attaching a high-tensile resin net, which is a gas conducting member, to the center opening of a frame member having a center of a stainless steel plate having a thickness of 0.15 mm and having a size including the suction area of the vacuum plate 40. Things. A metal net or a porous material may be used instead of the high-tensile resin net. The support plate 41 forms a layer in which air flows between the punching metal 43 and the vacuum plate 40, and aims to create a uniform ball suction state over the entire suction area of the vacuum plate 40.

As shown in FIG. 7, the second mount head 26 'includes a vacuum plate 40 having a fine suction hole 46 for suctioning a solder ball 47 on the lower surface of the mount head 26', and a vacuum plate 40 And a spacer 42 provided on the outer periphery of the suction area of the solder ball 47.

The spacer 42 includes a vacuum plate 40
Is provided to protrude below the mount head outside of the suction region of FIG. The thickness of the spacer 42 is, as shown in FIG.
It is determined according to the diameter of the solder ball 47, and at the time of mounting, the solder ball 47 is
A dimension that can be slightly pressed is preferable.

In the embodiment, the spacer 42 has a thickness of 0.25 mm with respect to the diameter of the solder ball 47 of 0.3 mm. The spacer 42 prevents indentation on the solder ball 47 during mounting.

The third mount head 25 has, as shown in FIG. 8, the elements of a first mount head 26 and a second mount head 26 ', and includes a support plate 41, a vacuum plate 40, and a spacer. 42
Are integrated by a plate holder 44, and are attached to the lower part of the mount head 25 along the lower surface of the punching metal 43.

As shown in FIG. 4, the mount head 25 has a Y-axis reciprocating between a ball supply device 19 and a ball mounting position 20 on the work drive mechanism 4 and a Z-axis (elevation axis). A drive mechanism for the shaft is provided. In the figure, reference numeral 35 denotes a Z-axis drive motor, and reference numeral 35 'denotes a Y-axis drive motor. The Y-axis driving mechanism here is used for positioning the mount head 25 and the work together with the role of the movement of the mount head 25.

The ball supply device 19 has a structure like a parts feeder. A vibrator is attached to a ball tray 27 for supplying solder balls 47 to the mount head 25. Due to the vibration of the vibrator, the solder ball 47 is flipped up obliquely upward.
The solder balls 47 move around the ball tray 27.

Above the ball tray 27, a supply port 28 for supplying a solder ball 47 from a ball stocker (not shown) into the ball tray 27 is disposed so as to be able to advance and retreat. A sensor 29 for detecting the remaining amount of balls in the ball tray 27 is attached to the tip of the supply port 28, and when a shortage of remaining balls is detected, a fixed amount of solder balls 47 is supplied from a ball stocker. The supply port 28 is provided with the solder ball 4
At the time of suction, the structure 7 is retracted outside the ball tray 27 to avoid interference with the mount head 25.

The surplus ball removing device 21 is a removal nozzle for removing excess balls adsorbed on the mount head 25.

The ball suction error inspection device detects a suction error such as a missing ball or an extra ball (excess ball) and a remaining ball as a mounting error by using four line CCD cameras 22 and 22 '.

Hereinafter, an operation procedure of the solder ball mounting apparatus using the third mount head 25 will be described.
First, the robot 49 supplies wafers 49 one by one from the supply wafer cassette 5 onto the wafer stage 30 at the wafer positioning position 8. When the wafer 49 is supplied, the wafer stage 30 starts vacuum suction through a hole on the upper surface of the wafer stage 30 through a blower motor (not shown) to hold the wafer 49.

The target mark or the wiring pattern of the held wafer 49 is read by the two CCD cameras 31 arranged above the wafer positioning position 8, and the position of the wafer 49 on the wafer stage 30 is recognized. Data is sent to a control device (not shown). Wafer 4
The wafer stage 30 for which the position recognition of 9 has been completed moves to the flux transfer position 11. At this time, the wafer stops at a position that takes into account the deviation of the X axis stored at the time of wafer positioning.

Next, in the flux supply device 10, the flux surface is leveled by the squeegee
When the transfer head 13 comes into contact with the flux supply unit 16 and a load of a predetermined pressure or more is applied, it is determined that the supply of the flux has ended, and the lowering of the transfer head 13 is stopped.
To rise.

Thereafter, the wafer is moved to the flux transfer position 11, and the alignment marks of the transfer head 13 are recognized by the two CCD cameras 23 and 23 'provided on the wafer stage 30. Taking into account the position data of the previously recognized wafer 49 to this recognition result, the wafer 49 is moved by one axis (Y axis) of the transfer head 13 and two axes (X axis,
And the transfer head 13 are aligned.

After the alignment, the transfer head 13 is lowered, and when the load on the Z-axis drive motor 34 of the transfer head 13 reaches a certain value, it is determined that the transfer is completed.
To rise. After ascending, the transfer head 13 returns to the flux supply device 10, and the wafer stage 30 moves to the ball mounting position 20.

On the other hand, the mount head 25 descends from above the ball supply device 19 and stops at the designated position. The inside of the mount head 25 is exhausted from the exhaust port 50 by a blower motor (not shown), and the pressure is reduced. Accordingly, the vacuum plate 40 and the support plate 41 are
Adhere to Even in this state, the punching metal 43 has a large number of gas conducting paths 51, and the gap in the high tension resin mesh of the support plate 41 sandwiched between the punching metal 43 and the vacuum plate 40, as shown by arrows in FIG. As shown, each suction hole 46 of the vacuum plate 40 is sucked.
A vacuum pressure is generated. As a result, the solder balls 47 are sucked into the suction holes 46.

When the internal pressure of the mount head 25 becomes lower than the predetermined pressure, it is determined that the suction is completed, and the mount head is raised. After that, the surplus balls are removed by the surplus ball removing device 21 and the apparatus moves to the ball suction error inspection device.

If there is a ball suction error, if the ball is a missing ball, the ball is moved to the ball supply device 19 again and the suction operation is repeated. If there is an excess ball, the ball discharge device 24 enters below the mount head 25, discharges all the suction balls into the ball discharge device 24, moves to the ball supply device 19 again, and repeats the suction operation.

If there is no abnormality, the operation moves to the ball mounting position 20. At the ball mounting position 20, the CCD cameras 23, 2
At 3 ', the alignment mark on the lower surface of the mount head 25 is recognized, and positioning is performed in the same manner as the flux transfer position. After the positioning, the mount head 25 descends, and the spacer 42 on the lower surface of the mount head 25 comes into contact with the wafer 49, and stops descending when a load detected by a load sensor (not shown) reaches a preset value.

At this point, the solder balls 47 are sandwiched between the mount head 25 and the wafer 49. Here, the blower motor is stopped, and the pressure in the mount head 25 is released to the atmospheric pressure. At this moment, the support plate 41 and the vacuum plate 40 receive a force in a direction away from the punching metal 43. With this force, the solder balls 47 are surely separated from the mount head 25 and mounted on the wafer 49. The mount head 25 then rises.

After the mounting of the solder balls 47, the wafer stage 30 returns to the wafer positioning position 8, but the CCD camera 3 previously moved to the ball mounting inspection position
In step 1, the mounting status of the solder balls 47 on the wafer 49 is inspected.

At this time, the CCD camera 31 is stopped, and the movement of the wafer stage 30 causes the CCD camera 31 to move.
Scans the entire surface. As a result of the inspection, if the mount is good, the robot 9 inserts it into the unloading wafer cassette 6 if the mount is not good, and into the defective wafer cassette 7 if the mount is bad.

[0042]

Normally, a conventional vacuum plate provided with a large number of suction holes for balls requires a certain degree of rigidity, so that a thick material (resin, metal, etc.) is used, and the suction holes are made of a spindle or the like. I was working by machining. However, in machining, the cost increases particularly when the number of holes is large, so that attempts have been made to reduce the thickness of the vacuum plate. As one example, it has been proposed to constitute a mount head by backing a porous material. However, when a porous material is used, the pressure loss is large and a large pressure reducing means is required. Further, when the thickness of the porous material is reduced to reduce the pressure loss, there is a problem that the strength is not provided.

However, the present invention provides a vacuum plate having a large number of suction holes for sucking a ball, and a support plate having a gas passage which does not correspond to the suction holes of the vacuum plate and supporting the vacuum plate from external force. And, since the mount head is provided with a gas-permeable member having air permeability arranged in the suction area of the vacuum plate between the vacuum plate and the support plate, even if a thin material is used for the vacuum plate or the gas-conductive member, The support plate was able to prevent the deflection due to the negative pressure at the time of attracting the solder balls, and was able to secure the parallelism between the workpiece and the vacuum plate. As a result, a large amount of solder balls can be accurately mounted on the work.

Second, since a thin plate can be used for the vacuum plate, the vacuum plate follows the work surface at the time of mounting, so that the mounting accuracy is good, the suction holes can be easily formed, and the cost of parts can be reduced. I could do it. Further, since a thin gas conducting member can be used, a large-sized decompression means is not required.

Third, by providing the gas conducting member, a layer in which air flows is formed between the support plate and the vacuum plate, and a uniform ball suction state can be created over the entire suction area. .

According to the second and third aspects of the present invention, since a spacer having a thickness corresponding to the diameter of the suction ball is provided outside the suction area of the vacuum plate, an impression is formed on the solder ball during mounting. Can be prevented.

[Brief description of the drawings]

FIG. 1 is a plan view of a solder ball mounting device.

FIG. 2 is an explanatory view showing a CCD camera for inspection at a wafer positioning position.

FIG. 3 is a side view of a flux transfer unit.

FIG. 4 is a side view of a ball mount unit.

FIG. 5 is a sectional view showing a use state of the first mount head.

FIG. 6 is an enlarged sectional explanatory view of a lower portion of the first mount head.

FIG. 7 is a sectional view showing a use state of the second mount head.

FIG. 8 is a sectional view showing a use state of a third mount head.

[Explanation of symbols]

 1. . . . . . . . 1. Wafer supply unit . . . . . . . Flux transfer unit 3. . . . . . . . Ball mount part 4. . . . . . . . Work drive mechanism 5, 6, 7. . . . 7. Wafer cassette . . . . . . . 8. Wafer positioning position . . . . . . . Robot 10. . . . . . . Flux supply device 11. . . . . . . 11. Flux transfer position . . . . . . Cleaning unit 13. . . . . . . Transfer head 15. . . . . . . Squeegee 16. . . . . . . Flux supply unit 19. . . . . . . Ball supply device 20. . . . . . . Ball mount position 21. . . . . . . Excess ball removing device 22, 22 ', 23, 23', 31. . . CCD camera 24. . . . . . . Ball discharging device 25, 26, 26 '. . . . Mount head 27. . . . . . . Ball tray 28. . . . . . . Supply port 29. . . . . . . Sensor 30. . . . . . . Wafer stage 32. . . . . . . Illuminators 33, 34, 34 ', 35, 35'. . . Motor 40. . . . . . . Vacuum plate 41. . . . . . . Support plate 42. . . . . . . Spacer 43. . . . . . . Punching metal 44. . . . . . . Plate holder 46. . . . . . . Adsorption hole 47. . . . . . . Solder ball 49. . . . . . . Wafer 50. . . . . . . Exhaust port 51. . . . . . . Gas conduction path

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) H05K 13/04 H01L 23/12 L F-term (Reference) 3F061 AA01 CA01 CB05 CC00 DB03 DB06 5E313 AA11 AA31 CC03 CC04 CC05 CD01 DD02 DD03 DD13 DD21 EE02 EE13 EE16 EE24 EE25 EE33 EE38 FF24 FF26 FF31 FG05 FG06 5E319 BB04 CD25 CD51

Claims (3)

[Claims] 1. A vacuum plate having a plurality of suction holes for sucking balls, a support plate having a gas conduction path not corresponding to the suction holes of the vacuum plate, supporting the vacuum plate from external force, and a vacuum plate. A mount head in a ball mount device, comprising: a gas-permeable member having gas permeability arranged in a suction area of a vacuum plate between the support plate and the support plate. 2. A mounting head in a ball mounting device, wherein a spacer having a thickness corresponding to a diameter of a suction ball is formed to protrude downward from the suction area of a vacuum plate toward a lower portion of the mounting head. 3. A vacuum plate having a plurality of suction holes for sucking balls, a support plate having a gas passageway not corresponding to the suction holes of the vacuum plate, supporting the vacuum plate from external force, and a vacuum plate. And a permeable gas conducting member disposed in the suction area of the vacuum plate between the mounting plate and the support plate, and a spacer having a thickness corresponding to the diameter of the suction ball is provided below the mount head outside the suction area of the vacuum plate. A mount head in a ball mount device, which is formed so as to protrude toward the mount.