JP3449192B2 - Apparatus and method for transferring conductive balls - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive ball transfer device and method for transferring conductive balls onto a work.

[0002]

2. Description of the Related Art Flip chips and BGA (Ball G)
A method using conductive balls such as solder balls is known as a method of manufacturing an electronic component with bumps such as a grid array. Further, as a method of transferring the conductive balls to a work such as a chip or a substrate, a method using a suction head has been implemented.

According to this method, conductive balls stored in a container or the like are vacuum-sucked and picked up in a large number of suction holes formed on the lower surface of the suction head, and the suction head is moved above the work to conduct these conductive balls. Since the conductive balls are transferred onto the electrodes of the work and a large number of conductive balls can be transferred onto the work all at once, there is an advantage that workability is good.

[0004]

However, in the method of transferring the conductive balls to the work by using the suction head, a pickup error as described below tends to occur when the conductive balls are vacuum-sucked. . That is, when the conductive balls are vacuum-sucked by the suction head, the suction head is lowered into the supply portion of the conductive balls accumulated by stacking a large number of conductive balls. However, one conductive ball is not always vacuum-adsorbed. For example, when a plurality of conductive balls are vacuum-sucked to one suction hole and a large number of conductive balls are continuously attached to the lower surface of the suction head, or when the conductive balls remain attached to positions other than the suction hole. The suction head may rise.

In order to detect the excessively attracted conductive balls in this way, conventionally, a camera is used to image the lower surface of the attracting head that attracts the conductive balls, and the presence or absence of the extra conductive balls is determined by image recognition. The method was used. However, with the decrease in diameter of the conductive balls,
The method based on image recognition has a problem that the determination result is not always stable due to variations in reflected light, and that it takes a considerable time for recognition.

Therefore, the present invention provides a conductive ball transfer device and transfer method capable of reliably and quickly detecting a conductive ball pickup error and correctly transferring the conductive ball onto the electrode of the work. The purpose is to provide.

[0007]

According to a first aspect of the present invention, there is provided a conductive ball transfer device having a suction head having a plurality of suction holes for sucking the conductive balls formed on a lower surface thereof, and a ball supplying the conductive balls. a supply unit, a positioning unit for positioning the workpiece, the vertical movement means for vertically moving the suction head, moving means for the suction head is moved between the positioning portion ball supply unit, the adsorption of the pre-Symbol suction head and <br/> abutment table which is displaced downward by the conductive balls adsorbed in pores abuts the lower surface of the suction head by a displacement detecting means for detecting an abnormal downward displacement of the abutment table
An inspecting unit for inspecting the presence or absence of extra conductive balls attached is provided.

According to a second aspect of the present invention, there is provided a conductive ball transfer method in which conductive balls in a ball supply portion are transferred to a work by a suction head having a plurality of suction holes for sucking the conductive balls formed on a lower surface thereof. A method of transferring conductive balls, the step of lowering the suction head that has sucked the conductive balls relative to an inspection unit that inspects for the presence of extra conductive balls that have adhered to the lower surface of the suction head; The step of contacting the conductive ball sucked on the lower surface of the suction head to the contact table of the inspection unit, the step of detecting the displacement of the contact table by the displacement detecting means, and the step of detecting the displacement based on the displacement detection result. And a step of determining the presence or absence of extra conductive balls attached.

According to the present invention having the above-mentioned structure, the suction head is lowered with respect to the contact table of the inspection unit so that the conductive balls sucked on the lower surface of the suction head are brought into contact with the contact table, and the contact table is contacted. It is possible to determine the presence or absence of extra conductive balls attached to the lower surface of the suction head by detecting the displacement in the vertical direction of.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will 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 sectional view of an inspection portion of the conductive ball transfer device, and FIGS. 3 and 4 are the conductive balls. 6 is a partial sectional view of a ball supply portion of the transfer device of FIG. 5, FIG. 5 is a partial sectional view of a suction head of the conductive ball transfer device of FIG.
FIG. 4 is a partial front view of a positioning table 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 2 is provided on a base 1. The positioning table 2 is composed of a Y table 3 and an X table 4.
A holder 5 is provided on the X table 4, and the holder 5 holds the work 6. Therefore, the work 6 is positioned at a predetermined position by driving the positioning table 2.

A supply unit 10 for the conductive balls 7 is provided at the end of the base 1 opposite to the positioning table 2. The ball supply unit 10 includes a ball tank 11, and a plurality of layers of mesh plates 12 are horizontally spread inside the ball tank 11. The mesh plate 12 is provided with an innumerable number of openings whose size does not allow the conductive balls 7 to pass through. The conductive balls 7 are stored on the uppermost mesh plate 12. A nozzle 14 is arranged at the bottom of the ball tank 11, and 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 7 to fluidize the conductive balls 7.

Next, the suction head 31 on which the conductive balls 7 are transferred will be described. Reference numeral 20 shown in FIG. 1 is a moving means for moving the suction head 31 between the ball supply unit 10 and the positioning table 2. The suction head 31 is held by the block 30, and a plurality of suction holes 31 a are provided on the lower surface of the suction head 31. The block 30 is a vertical guide rail 2 provided on the front surface of the bracket 24.
It is attached to 5 so that it can move up and down. In block 30,
A nut 28 is integrally provided, and a vertical feed screw 26 is screwed into the nut 28. Therefore, when the Z-axis motor 27 is driven forward and backward and the feed screw 26 rotates forward and backward, the suction head 31 is guided by the guide rail 25 and moves up and down. Therefore, the Z-axis motor 27 and the feed screw 26 are vertical moving means for moving the suction head 31 up and down.

A nut (not shown) provided on the rear surface of the bracket 24 is screwed onto the horizontal feed screw 22.
Reference numeral 21 is 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 horizontally moves between the positioning table 2 and the ball supply unit 10.

In FIG. 1, a ball supply unit 1 on a base 1
An inspection unit 40 is arranged on the side of 0. Inspection unit 4
For 0, the presence or absence of the conductive balls 7 that are excessively adsorbed on the lower surface of the adsorption head 31 is inspected. The inspection unit 40 will be described below with reference to FIG. In FIG. 2, a pair of left and right brackets 42 are erected on a base 41. A slide bearing 44 is fixed to the side surface of the bracket 42. A horizontal contact table 43 is connected to the movable portion of the slide bearing 44.

The lower surface of the contact table 43 is supported by the rod 45a of the cylinder 45. Cylinder 45
Pushes the contact table 43 upward with a biasing force larger than the weight of the contact table 43. Therefore, when the contact table 43 is pressed downward with a load larger than this biasing force, the contact table 43 is displaced downward. Further, a proximity sensor 47 as a displacement detecting means is arranged on the block 46 of the base 41. The proximity sensor 47 is adjusted in height position and sensor sensitivity so that when the distance C from the lower surface of the contact table 43 becomes equal to or less than the set distance C0, it is detected as an abnormal displacement.

The set interval C0 is the state in which the conductive ball 7 is normally adsorbed on the lower surface of the adsorption head 31, that is, the adsorption hole 3
Based on the interval when the suction head 31 is lowered onto the contact table 43 and the conductive balls 7 are brought into contact with the upper surface of the contact table 43 in a state where the conductive balls are vacuum-adsorbed only on 1a. Is set. Therefore, the suction head 3
When the conductive balls 7 are present at positions other than the suction holes 31a on the lower surface of No. 1, the contact table 43 is displaced by being pushed down further below the above-mentioned reference, and the proximity sensor 47 and the contact table 43 are displaced. When the distance from the contact table 43 is smaller than the set interval C0, the abnormal displacement of the contact table 43, that is, the presence of the extra conductive ball 7 on the lower surface of the suction head 31 is detected.

Although the proximity sensor 47 is used as the displacement detecting means here, any other means may be used as long as it can detect the displacement of the contact table 43 with required accuracy. For example, a general displacement sensor or a touch sensor. It may be a sensor or the like.

This conductive ball transfer device has the above-mentioned structure, and its operation will be described below. First, in FIG. 1, the X-axis motor 23 is driven to move the suction head 31 above the ball supply unit 10. Then, the Z-axis motor 27 is driven to lower the suction head 31, and the lower surface of the suction head 31 is slightly sunk into the layer of the conductive balls 7 as shown in FIG. At this time, the nozzle 14 of the ball tank 11
More gas is blown upward (see arrow a), and the conductive balls 7 are fluidized by the flow of this gas. Therefore, the conductive ball 7 is blown up, hits the lower surface of the suction head 31 and is vacuum-sucked in the suction hole 31a.

At this time, as shown in FIG. 4, the suction head 31 may ascend while the extra conductive balls 7 are attached to positions other than the suction holes 31a on the lower surface of the suction head 31. FIG. 4 shows an example in which one extra conductive ball 7 is attached, but in addition to this example, a plurality of conductive balls 7 are attached.
There are various modes for attaching the extra conductive balls 7, such as when the lines are attached in series.

In order to inspect the adhered state of the conductive balls 7 as described above, the inspection unit 40 detects the presence or absence of the excessively adhered conductive balls 7. First, the suction head 31 that has suctioned the conductive balls 7 is moved to above the inspection unit 40, and then the suction head 31 is lowered with respect to the contact table 43. The contact table 43 is pushed down by the lower end of the conductive ball 7 attracted to the lower surface of the suction head 31 contacting the upper surface of the contact table 43.

At this time, as shown in FIG. 5, when the extra conductive balls 7a are attached to the lower surface of the suction head 31 at positions other than the suction holes 31a, the distance d shown in FIG. Since the contact table 43 is pushed down, that is, the distance C between the proximity sensor 47 and the lower surface of the contact table 43 becomes equal to or less than the set interval C0, the proximity sensor 47 detects an abnormal displacement. Further, in a case other than the mode of attachment of the extra conductive balls 7 shown in FIG. 5, for example, even when a plurality of conductive balls 7 are attached in series, the contact table 43 is pushed down excessively, and similarly, the contact table 43 is approached. An abnormal displacement is detected by the sensor 47. Therefore, the presence of the extra conductive balls 7 on the lower surface of the suction head 31 can be detected in any of the attachment modes of the extra conductive balls 7.

In this way, when an extra conductive ball 7 is detected on the lower surface of the suction head 31, the operation of the transfer device is stopped and the operator is informed accordingly. The operator takes measures to remove the conductive balls 7 that have been excessively attracted, or attaches the attraction head 31 to the ball supply unit 1.
After returning to 0 to release the vacuum suction, a re-suction operation is performed.

The conductive balls 7 that have been excessively attached are removed, and the conductive heads 7 are correctly vacuum-sucked and picked up in each of the suction holes 31a one by one.
It rises from the plate 13 and then moves horizontally above the positioning table 2. Next, the suction head 31 descends onto the work 6 held by the holder 5, and by releasing the vacuum suction, the conductive balls 7 are placed on the electrodes 6a as shown in FIG.
After the transfer, the substrate is moved up to complete the transfer of the conductive balls 7.

The present invention is not limited to the above embodiment. For example, in the above embodiment, the conductive ball inspection unit 40 is fixed, and the suction head 3 is attached to the inspection unit 40.
1, the inspection unit 40 is movable, and the suction head 3 is stationary on the ball supply unit 10.
It is also possible to move the inspection unit 40 with respect to 1 and detect the presence or absence of the extra conductive ball 7.

[0026]

According to the present invention, the suction head, which has sucked the conductive balls of the ball supply section, is brought into contact with the contact table of the inspection section and the displacement of the contact table is detected. It is possible to reliably detect the presence or absence of the conductive ball that is excessively adsorbed on the lower surface of the head. Therefore, when the conductive ball that is excessively adsorbed is detected, this is removed and 1 is placed on the electrode of the work. The conductive balls can be transferred individually.

[Brief description of 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 sectional view of an inspection portion of the conductive ball transfer device according to the embodiment of the present invention.

FIG. 3 is a partial cross-sectional view of a ball supply unit of a conductive ball transfer device according to an embodiment of the present invention.

FIG. 4 is a partial cross-sectional view of a ball supply unit of the conductive ball transfer device according to the embodiment of the present invention.

FIG. 5 is a partial sectional view of a suction head of a conductive ball transfer device according to an embodiment of the present invention.

FIG. 6 is a partial front view of a positioning table of the conductive ball transfer device according to the embodiment of the present invention.

[Explanation of symbols]

1 base 2 Positioning table 6 work 7 conductive balls 10-ball feeder 11 ball tank 23 X-axis motor 27 Z-axis motor 31 Suction head 31a adsorption hole 40 Inspection Department 43 Contact table 45 cylinders 47 Proximity sensor

Claims (2)

(57) [Claims] 1. A suction head having a plurality of suction holes for sucking conductive balls formed on a lower surface thereof, a ball supply unit for supplying the conductive balls, and a positioning unit for positioning a work.
And vertically moving means for vertically moving the suction head, the suction head moving means for moving between the positioning portion ball supply portion, said conductive balls sucked by the suction holes of the front Symbol suction head contacts By the contact table which is displaced downward by this, and the displacement detecting means which detects an abnormal downward displacement of the contact table , an excess is formed on the lower surface of the suction head.
An electroconductive ball transfer device comprising an inspection unit for inspecting the presence or absence of electroconductive balls adhered to the . 2. A conductive ball transfer method for transferring a conductive ball of a ball supply unit onto a work by a suction head having a plurality of suction holes for sucking conductive balls formed on a lower surface thereof. The step of lowering the suction head that has sucked the balls relative to an inspection unit that inspects the presence or absence of extra conductive balls that have adhered to the lower surface of the suction head, and the lower surface of the suction head on the contact table of the inspection unit. A step of abutting the conductive balls adsorbed on the substrate, a step of detecting the displacement of the abutting table by a displacement detecting means, and the presence or absence of the extra conductive balls attached is determined based on the detection result of the displacement. A method of transferring a conductive ball, comprising: