JP2000068311A - Suction method of micro-balls - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for suction of micro-balls, for which the occurrence of the possibility of suction nonconformities do not exist. SOLUTION: In a method for suction of conductive balls 2 that have been accommodated in a container 13 by an adsorption head 31, having suction holes 31a on its backside face, the adsorption head 31 is moved downward to the surface plane of the conductive balls 2 in the container 13 while the suction holes 31a is evacuated, and the lower side face of the suction head 31 is made to settle downward lower than the surface plane. After a specified duration of time elapse, the suction head 31 is moved horizontally back and forth several times, relative to the container 13. Through this action, the conductive balls 2 can be sucked stably to all of the suction holes 31a, one for each, when the suction head 13 begins to suck the conductive balls 2, and the suction nonconformities, in which a number of conductive balls 2 are sucked in shape of a bunch of grapes due to suction power leaking from the suction holes 31a, can be avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for sucking a minute ball such as a conductive ball by vacuum.

[0002]

2. Description of the Related Art As a method for transferring a conductive ball, which is a minute metal ball, to a work such as an electronic component, a method using vacuum suction is known. In this method, a suction head provided with a plurality of suction holes on a lower surface is lowered with respect to a container in which a large number of conductive balls are randomly stored, and the conductive holes are vacuum-sucked to the suction holes. In order to quickly perform the vacuum suction, conventionally, when the suction head descends to suck the conductive ball, the suction head is reciprocated horizontally relative to the container. This is for the purpose of improving the probability that the conductive ball is fitted into the suction hole and is sucked.

[0003]

However, with the increase in the number of conductive balls mounted on one electronic component, the size of the conductive balls has been reduced, and several hundred to several thousand pieces have been set within a narrow range. A full grid pattern in which conductive balls are densely arranged in a grid pattern has been adopted. However, in the case of using a suction head in which suction holes are densely arranged in a narrow range corresponding to the full grid pattern, grape-like suction of the conductive balls is likely to occur as described below. In this grape-shaped suction, the conductive balls are not sucked one by one in each suction hole, and a large amount of the conductive balls are sucked in a tuft of grapes on the entire lower surface of the suction head.

[0004] This phenomenon is a result of the vacuum suction force leaking without the suction holes being completely closed by the conductive balls as described above, and the vacuum suction force leaking to many conductive balls near the lower surface of the suction head. Occurs. However, conventionally, the operation of the suction head was set based on insufficient recognition, so as to merely improve the probability of approach between the conductive ball and the suction hole. Horizontal reciprocating motion, the stable suction of the conductive balls into each suction hole is rather hindered. There is a problem that a suction failure occurs.

Accordingly, an object of the present invention is to provide a method for adsorbing a minute ball, which can improve the suction failure.

[0006]

According to a first aspect of the present invention, there is provided a method of sucking a small ball, wherein the small ball is held by a suction head having a plurality of suction holes formed on a lower surface thereof. A step of lowering the suction head toward the surface layer of the micro-balls in the container while vacuum-sucking from the suction hole; and elapse of a predetermined time after lowering the lower surface of the suction head below the surface layer. Thereafter, the method includes a step of reciprocating the suction head relative to the container a plurality of times in the horizontal direction, and a step of lifting the suction head from the container.

According to a second aspect of the present invention, there is provided a method for adsorbing a minute ball.
2. The method according to claim 1, wherein the lowering speed of the suction head when the suction head is lowered toward the surface layer is 1 mm / sec. ５5 mm / sec. Is within the range.

According to the invention described in each of the claims, after a predetermined time has elapsed after the lower surface of the suction head is immersed below the surface layer of the conductive ball, the suction head is moved relative to the container in the horizontal direction. By reciprocating twice, the conductive ball can be stably adsorbed.

[0009]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a front view of a conductive ball transfer device according to an embodiment of the present invention, FIG. 2 is a block diagram showing a configuration of control of the conductive ball transfer device, and FIG. FIG. 3B is a timing chart showing the height of the suction head at the time of sucking the non-reactive ball, FIG. 3B is a timing chart of applying vibration to the ball supply unit, FIG. 4 (a), (b), (c), (d)
FIG. 4 is a sectional view of a ball supply unit of the conductive ball transfer device.

First, the overall structure of the conductive ball transfer device will be described with reference to FIG. In FIG. 1, a positioning table 5 is provided on a base 4. The positioning table 5 is movable in the X direction and the Y horizontal direction.
A holder 8 is provided on the positioning table 5,
The holder 8 holds the work 9. Therefore, by driving the positioning table 5, the work 9 is positioned at a predetermined position.

At the opposite end of the positioning table 5 on the base 4, a ball supply section 10 for the conductive balls 2 is provided. The ball supply unit 10 is formed by fitting a ball container 13 in a box 11, and a mesh plate 12 is horizontally extended at the bottom of the ball container 13. The mesh plate 12 has a myriad of openings having a size that does not allow the conductive balls 2 to pass through. The conductive balls 2 are stored on the mesh plate 12. Ball container 1
3, a nozzle 14 is provided below the nozzle 14.
Is connected to a gas supply source (not shown). By supplying the gas to the nozzle 14, the gas blown upward from the nozzle 14 passes through the openings of the mesh plate 12 and is blown into the layer of the conductive balls 2, thereby fluidizing the conductive balls 2.

Next, the suction head 31 for transferring the conductive balls 2 will be described. Reference numeral 20 shown in FIG. 1 denotes a moving unit that moves the suction head 31 between the ball supply unit 10 and the positioning table 5. The suction head 31 is held by a block 30, and a plurality of suction holes 31 a are provided on a lower surface of the suction head 31. The inside of the suction head 31 is connected to a pressure sensor 42 via a pipe 45, and further connected to a vacuum suction means (not shown) via a valve 44. The vacuum suction means is driven to open the valve 44, and the inside of the suction head 31 is vacuum-sucked, so that the conductive ball 2 is sucked into the suction hole 31a by vacuum suction. The pressure sensor 42 detects the pressure in the suction head 31 during vacuum suction.

The block 30 is vertically movably mounted on a vertical guide rail 25 provided on the front surface of the bracket 24. A nut 28 is provided integrally with the block 30, and a vertical feed screw 26 is screwed to the nut 28. Therefore, when the Z-axis motor 27 is driven forward and reverse to rotate the feed screw 26 forward and backward, the suction head 31 is guided by the guide rail 25 and moves up and down. Therefore, Z
The shaft motor 27 and the feed screw 26 serve as up and down moving means for moving the suction head 31 up and down. Z-axis motor 2
7 is provided with an encoder 29 as height position detecting means, and can detect the height of the suction head 31 by counting the number of rotations of the Z-axis motor 27.

A nut (not shown) provided on the back of the bracket 24 is screwed to the horizontal feed screw 22.
Reference numeral 21 denotes a holding table for the feed screw 22. Therefore, when the X-axis motor 23 rotates forward and backward, the feed screw 22 rotates forward and backward, and the suction head 31 held by the bracket 24 moves horizontally between the positioning table 5 and the ball supply unit 10.

A slider 33 is fixed to the bottom surface of the box 11, and the slider 33 is slidably fitted in a horizontally arranged guide rail 32 in the horizontal direction. A bearing 34 is provided downward on the bottom surface of the box 11, and a cam follower 36 is mounted on the bearing 34. The bearing 34 is urged in one direction by a spring 35. The cam follower 36 is a motor 3
8 is in contact with the eccentric cam 37 connected to the eccentric cam 37. Motor 3
By driving the eccentric cam 37 by driving the cam 8, the cam follower 36 reciprocates in the horizontal direction, so that the entire box 11 also reciprocates in the horizontal direction, and the ball container 13 and the conductive balls 2 in the ball container 13 are reciprocated. Is given vibration.

Next, the configuration of the control system will be described with reference to FIG. In FIG. 2, a control unit 41 is a CPU, which controls the overall operation of the conductive ball transfer device. The pressure sensor 42 monitors the pressure in the suction head 31 and transmits a result of the pressure detection to the control unit 41. The encoder 29 counts the number of rotations of the motor 27 and outputs the count result to the control unit 4.
The control unit 41 detects the height position of the suction head 31 based on the count result. The storage unit 43 stores the ball suction height of the suction head 31 obtained when the detection value of the pressure sensor 42 reaches a predetermined value. Further, the control unit 41 controls the driving of the X-axis motor 23, the Z-axis motor 27, the motor 38 for imparting vibration of the ball supply unit 10, and the valve 44 for opening and closing the vacuum suction path of the suction head 31.

The device for transferring conductive balls is configured as described above. The operation of attracting conductive balls, which are minute balls, will be described below with reference to FIGS.
The graph of FIG. 3A shows that the suction head 31 is moved up and down with respect to the ball supply unit 10 so that the suction hole 3 of the suction head 31 is moved.
FIG. 3A shows the height position of the suction head 31 during the suction operation of picking up the conductive ball 2 by vacuum suction. FIG. 3B shows ON of the application of vibration to the ball supply unit 10 at that time. The timing of -OFF is shown.

The height h0 shown in FIG.
When the start command of the suction operation is issued at timing t0, the suction head 31 starts to descend at high speed toward the surface layer of the conductive balls 2 in the ball container 13 (FIG. 4A). reference). Then, at timing t1 when the preset high / low switching height h1 is reached, the lowering speed of the suction head 31 is switched to low. The lowering speed at this low speed is 1 mm / sec. ５5 mm / sec. Is set in the range. At this time, the valve 44 is already in the open state, and the suction hole 31a of the suction head 31 is performing vacuum suction.

As the suction head 31 gradually descends, the lower surface of the suction head 31 sinks below the surface layer of the conductive ball 2 as shown in FIG. Comes into contact with the sex ball 2. Some of the conductive balls 2 are captured by the suction force of the suction holes 31a and are sucked in vacuum. As a result, FIG.
As shown in (c), the measurement value of the pressure sensor 42 is equal to the normal pressure P.
Start descent from zero.

The pressure drop start timing t2
The height h2 of the suction head 31 corresponding to
The control unit 41 obtains the count value based on the count value of 9 and stores it in the storage unit 43 as the suction height. Thereafter, the suction head 31 descends to a lower limit height h3 set below the suction height h2 by a predetermined amount, and stops the lifting operation during the suction time from the timing t3 to the timing t5. At this time, at a timing t4 after a lapse of a predetermined time from the timing t3, as shown in FIG.
Is started, the suction head 31 is reciprocated a plurality of times relative to the ball container 13, and vibration is applied to the conductive balls 2 inside the ball container 13 (FIG. 4).
(C)). As a result, the conductive balls 2 are vacuum-sucked in all the suction holes 31a on the lower surface of the suction head 31, and as a result, the measured value of the pressure sensor 42 drops to a predetermined level P0, and the vacuum suction is performed normally. Is confirmed.

Thereafter, as shown in FIG. 4D, the suction head 31 starts rising at a low speed at a timing t5, and shifts to a high speed rising at a timing t6 when the height has been raised by a predetermined height. During this time, the vibration is continuously applied to the ball supply unit 10,
By this vibration, extra balls extraly attached to the lower surface of the suction head 31 are removed, and the extra balls fall into the ball container 13. Then, the suction head 31 is raised to the original position height h0, and the suction operation is completed. Thereafter, the suction head 31 holds the conductive ball 2 and moves above the work 9, where the suction head 31 moves up and down again to release the vacuum suction, thereby transferring the conductive ball 2 onto the work 9. I do.

As described above, when the lower surface of the suction head 31 sinks below the surface layer of the conductive ball 2, no vibration is applied to the ball container 13 and the relative position between the suction head 31 and the ball container 13 is reduced. By lowering the suction head 31 at a low speed without any horizontal reciprocation, one conductive ball 2 is stably captured corresponding to one suction hole 31a, and the vacuum suction force from the suction hole 31a is reduced. No leaks occur. Therefore, the plurality of conductive balls 2 are formed in the suction holes 31a.
It is possible to prevent the phenomenon of grape-like adsorption from adhering due to the leaked vacuum suction force while not being normally adsorbed to the substrate.

In the present embodiment, a conductive ball is described as an example of a minute ball. However, the present invention is not limited to this. Generally, a minute ball-shaped object is picked up by vacuum suction. Can be applied to the case.

[0024]

According to the present invention, the suction head is moved a plurality of times in the horizontal direction relative to the container after a predetermined time elapses after the lower surface of the suction head is immersed below the surface layer of the conductive ball. By doing so, the conductive balls can be stably adsorbed.

[Brief description of the drawings]

FIG. 1 is a front view of a conductive ball transfer device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a control configuration of a conductive ball transfer device according to an embodiment of the present invention.

FIG. 3 (a) is a graph showing the height of a suction head during suction of a conductive ball according to one embodiment of the present invention; and (b) timing of applying vibration to a ball supply unit according to one embodiment of the present invention. Chart (c) A graph showing the pressure level in the suction head according to one embodiment of the present invention.

FIG. 4A is a cross-sectional view of a ball supply unit of a conductive ball transfer device according to one embodiment of the present invention. FIG. 4B is a cross-sectional view of the conductive ball transfer device of one embodiment of the present invention. Sectional view of section (c) Sectional view of ball supply section of conductive ball transfer apparatus according to one embodiment of the present invention (d) Ball supply of conductive ball transfer apparatus of one embodiment of the present invention Sectional view of part

[Explanation of symbols]

 2 conductive ball 5 positioning table 9 work 10 ball supply unit 13 ball container 20 moving means 29 encoder 31 suction head 31a suction hole 42 pressure sensor 43 storage unit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 21/92 604Z

Claims (2)

[Claims] 1. A method of sucking a minute ball stored in a container by a suction head having a plurality of suction holes formed on a lower surface thereof, wherein the suction head is vacuum-sucked from the suction hole to the container. A step of lowering the suction head toward the surface layer of the microballs therein, and after elapse of a predetermined time after lowering the lower surface of the suction head below the surface layer, moving the suction head relative to the container in the horizontal direction. And a step of raising the suction head from the container a plurality of times. 2. A descent speed of the suction head when lowering the suction head toward the surface layer is 1 mm / sec. ~
5 mm / sec. 2. The method according to claim 1, wherein the distance is in the range of: