JP3539258B2 - Mounting device for conductive balls - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention, on an electrode of a work such as a chip or a substrate, it relates to mounting equipment of the conductive ball mounting the conductive balls for forming bumps.
[0002]
[Prior art]
As a method of forming bumps (protruding electrodes) on electrodes of a work in a process of manufacturing a work with a bump such as a flip chip, a method using a conductive ball such as a solder ball is known. In addition, as a method using conductive balls, the mounting head is moved above the conductive ball supply section, and the mounting head is moved up and down so that the mounting head picks up a large number of conductive balls, and then There is known a method in which the mounting head is moved above a work, and is moved up and down to collectively mount a large number of conductive balls on electrodes of the work.
[0003]
[Problems to be solved by the invention]
However, in the above-mentioned conventional method, the mounting head easily picks up an extra conductive ball (in the present invention, this extra ball is referred to as an “extra ball”) in the supply portion of the conductive ball. There is a problem that this extra ball is also erroneously mounted and a defective work is produced.
[0004]
Accordingly, the present invention aims at providing a mounting equipment of the conductive balls can be eliminated from being mounted incorrectly extra ball to the work.
[0005]
[Means for Solving the Problems]
According to the present invention, there is provided a detecting means for detecting an extra ball erroneously attached to the mounting head and a remaining ball remaining on the lower surface of the mounting head without being mounted on a work, on a moving path of the mounting head.
[0006]
The suction holes at the bottom of the mounting head is large number form, the conductive balls in the suction hole and held by vacuum suction, also said detecting means, a pre-Symbol light path is blocked by the extra ball and the remaining balls Having an optical element.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
ADVANTAGE OF THE INVENTION According to this invention, the extra ball erroneously attached to the mounting head can be detected, and only the conductive ball of the mounting head from which no extra ball is detected can be mounted on the work. Further, it is possible to detect a remaining ball that is not mounted on the work and remains and adheres to the lower surface of the mounting head.
[0009]
Next, embodiments of the present invention will be described with reference to the drawings.
[0010]
(Embodiment 1)
FIG. 1 is a side view of a conductive ball mounting apparatus according to a first embodiment of the present invention, FIGS. 2 and 3 are explanatory views of a transfer operation of the conductive ball, and FIG. 4 is a perspective view of a detection unit of the extra ball. FIG. 5 is an explanatory diagram of the extra ball detecting operation, FIG. 6 is an explanatory diagram of the remaining ball detecting operation, and FIG. 7 is a partially enlarged sectional view of a lower portion of the mounting head.
[0011]
In FIG. 1, reference numeral 1 denotes a solder ball as a conductive ball, which is stored in a container 2. Reference numeral 3 denotes a base on which the container 2 is placed. Vibration means for vibrating the container 2 and gas supply means for feeding gas into the container 2 are provided inside the base 3 to fluidize the solder balls 1 in the container 2. A brush 4 projects upward from the right wall of the container 2. The container 2 and the base 3 constitute a supply unit for the solder balls 1.
[0012]
In FIG. 1, reference numeral 10 denotes a work, which is positioned by being clamped to a clamper 11. The clamper 11 is supported by a column 13 erected on the base 12. The clamper 11, the base 12, and the support 13 serve as a positioning part of the work 10. A case 14 is provided between the container 2 and the work 10 as a collecting part of the solder ball 1. In FIG. 4, brackets 15 and 16 are erected on both sides of the case 14. The light emitting element 17 is mounted on the inner surface of the bracket 15, and the light receiving element 18 is mounted on the inner surface of the bracket 16. The light emitting element 17 and the light receiving element 18 are connected to the detection unit 20 via a cable 19. The detection unit 20 is connected to the control unit 21. L is an optical path of light emitted from the light emitting element 17 to the light receiving element 18. The light emitting element 17 and the light receiving element 18 constitute an extra ball detecting means.
[0013]
In FIG. 1, reference numeral 22 denotes a mounting head. The mounting head 22 is held below the box 23. A motor 24 is provided above the box 23. The box 23 has built-in vertical movement means such as a feed screw driven by a motor 24. When the motor 24 is driven, the mounting head 22 moves up and down. As shown in FIG. 7, a large number of suction holes 25 are formed below the mounting head 22. The mounting head 22 is connected to a pneumatic unit (not shown). When the pneumatic unit is driven, the solder ball 1 is sucked and held in the suction hole 25 by vacuum, and the solder ball is released by releasing the vacuum suction state. Drop 1
[0014]
The suction hole 25 is provided with a tapered recess 25a capable of accommodating only one solder ball 1, and is accommodated in the recess 25a when the solder ball 1 is normally sucked. On the other hand, since the extra ball 1A is not accommodated in the concave portion and adheres to the lower surface 22a of the mounting head 22, a difference in height between the extra ball 1A and the normally sucked solder ball 1 is generated. In the conductive ball mounting apparatus according to the first embodiment, the extra ball 1A can be detected and distinguished from the normally attracted solder ball 1 by utilizing the height difference between the normal solder ball 1 and the extra ball 1A. ing.
[0015]
The box 23 is held on a horizontally long moving table 26 as moving means. The moving table 26 has a built-in feed screw mechanism. When the motor 27 is driven to operate the feed screw mechanism, the mounting head 22 moves between the container 2, the case 14, and the work 10 in the horizontal direction.
[0016]
This conductive ball mounting device is configured as described above, and the operation will be described next. In FIG. 1, the mounting head 22 moves above the container 2 and performs a lowering and ascending operation, whereby the solder ball 1 is vacuum-adsorbed to the suction hole 25 below the container 2 and picked up. FIG. 7 shows a lower portion of the mounting head 22 that picks up the solder ball 1. As shown in the drawing, one solder ball 1 is vacuum-sucked in each suction hole 25. In FIG. 7, however, one extra conductive ball (extra ball) 1A is attached. . If the extra ball 1A is mounted on the work 10, the work 10 becomes defective. Therefore, the extra ball 1A must not be mounted on the work 10. The extra ball 1A is generated due to adhesion of solder balls due to static electricity or vacuum leakage of the suction hole 25.
[0017]
Now, in FIG. 1, the mounting head 22 that has picked up the solder ball 1 moves rightward toward the work 10 (see also FIG. 2). At this time, the mounting head 22 passes above the brush 4, and the upper end of the brush 4 comes into sliding contact with the solder ball 1 held on the lower surface of the mounting head 22. Among the solder balls shown in FIG. 7, the normal solder ball 1 that has been correctly vacuum-sucked directly into the suction hole 25 is strongly vacuum-sucked and held, so that it does not drop even when the brush 4 slides, but the extra ball 1A Is held by a weak force due to static electricity or the like. If the brush 4 is provided in the movement path of the mounting head and the brush 4 is slid in contact with the solder ball 1 as in the present embodiment, the extra ball 1A is transferred during the transfer of the solder ball 1 to the work 10. Can be easily dropped and removed. In addition, by providing the brush 4 in the container 2, the extra ball 1A dropped by the brush 4 can be collected in the container 2 as it is.
[0018]
Next, the mounting head 22 passes between the light emitting element 17 and the light receiving element 18 as shown in FIG. As shown in FIGS. 5 and 7, the level of the mounting head 22 is such that the light path L is not blocked by the normal solder ball 1, but is blocked by the extra ball 1 A protruding downward from the normal solder ball 1. Set to height. Of course, the level of the mounting head 22 is controlled by driving the motor 24. As described above, the extra ball 1A is slid and dropped by the brush 4, but the slid contact drop is not always successful, and the extra ball 1A still remains as shown in FIGS. You may have. Such an extra ball 1A is detected by blocking the light path L.
[0019]
As described above, when the extra ball 1A is detected, there are various methods, some of which will be described below. First, in the first method, the mounting head 22 is stopped above the case 14, and air is blown out from the suction holes 25 or the vacuum suction state is released by operating a pneumatic unit (not shown) in the opposite direction. By doing so, all the solder balls 1 and the extra balls 1A held by the mounting head 22 are dropped into the case 14 and collected. Then, the mounting head 22 is returned above the container 2, and the pickup operation is performed again.
[0020]
In the second method, the mounting head 22 is returned above the container 2 as shown by arrows Q1, Q2, and Q3 in FIG. 2, and is again moved above the brush 4 as shown by arrow Q4. The extra ball 1A is slid and dropped again.
[0021]
A third method is to return the mounting head 22 to a position above the container 2, and then lower the mounting head 22 so that the lower surface of the mounting head 22 protrudes into the layer of the solder balls 1 stored in the container 2 in a large amount. By driving the motor 27 forward and reverse in this state, the extra head 1A is forcibly shaken down by causing the mounting head 22 to perform a scrub operation in the lateral direction. As described above, the extra ball 1A can be removed by various methods.
[0022]
Now, the mounting head 22 from which the extra balls 1A have been removed moves above the work 10 in FIG. Then, the mounting head 22 descends to land the solder ball 1 on the electrode of the work 10. Next, when the vacuum suction state of the solder balls 1 is released and the mounting head 22 is raised, the solder balls 1 are mounted on the electrodes of the work 10. The work 10 on which the solder balls 1 are mounted is sent to a heating furnace (not shown), and the solder balls 1 are melted and solidified by heating to form bumps. In order to heat and melt the solder ball 1, a flux is required. The flux is applied to the lower surface of the solder ball 1 held on the lower surface of the mounting head 22 or the electrode of the work 10 by means not shown.
[0023]
Now, as described above, when the mounting head 22 mounts the solder ball 1 on the work 10, the mounting head 22 returns above the container 2. FIG. 6 shows the mounting head 22 passing over the case 14 during this return. 1B is a solder ball remaining on the lower surface of the mounting head 22 (hereinafter, referred to as a “remaining ball”). The remaining ball 1B fails to be mounted on the work 10 and remains on the lower surface of the mounting head 22.
[0024]
The remaining ball 1B is detected by blocking the light path L. By driving the motor 24, the height of the mounting head 22 is set slightly lower on the return path than on the forward path, or by slightly raising the case 14 with a lifter (not shown) as shown in FIG. The light path L is blocked by the remaining ball 1B, and this can be detected.
[0025]
When the remaining ball 1B is detected, the previous work 10 is a defective product having a shortage of the solder ball. Therefore, the remaining work 1 is removed from the line, or the solder ball 1 is removed from the electrode where the solder ball 1 does not exist by a separate recovery means. Replenish. In FIG. 6, the remaining balls 1B are forcibly dropped into the case 14 and collected by blowing air from the suction holes 25 of the mounting head 22. Next, the mounting head 22 returns above the container 2, and the above-described operation is repeated.
[0026]
(Embodiment 2)
FIG. 8 is a side view of a conductive ball mounting apparatus according to Embodiment 2 of the present invention, and FIG. 9 is a light / dark image of the camera. Reference numeral 30 denotes a camera, and 31 denotes a light source for irradiating illumination light upward. The light source is provided below the moving path of the mounting head 22 instead of the light emitting element 17 and the light receiving element 18. The mounting head 22 picking up the solder balls 1 in the container 2 moves above the camera 30 and is observed by the camera 30.
[0027]
FIG. 9 shows an image obtained by the camera 30. The solder ball 1 is a glossy metal sphere. When light is irradiated from below, only the light incident on the center is strongly reflected downward and enters the camera 30, so that only the center of the solder ball 1 is brightly observed. Is done. The lower surface of the mounting head 22 is darkened such as black so that the camera 30 can observe the surface black. In FIG. 9, 1 'is an image of a normal solder ball 1, and 1A' is an image of an extra ball. Therefore, the presence of the extra ball 1A can be easily detected by analyzing this image by a known image processing technique.
[0028]
(Embodiment 3)
FIG. 10 is a side view of a conductive ball mounting apparatus according to Embodiment 3 of the present invention, and FIG. 11 is a partial side view of the same. Reference numeral 32 denotes a laser unit, which is provided below the moving path of the mounting head 22 in place of the light emitting element 17 and the light receiving element 18.
[0029]
By irradiating the laser spot light from the laser unit 32, scanning the laser spot light over the entire lower surface of the mounting head 22, and receiving the reflected light, the level distribution on the lower surface of the mounting head 22 can be detected. Since the extra ball 1A protrudes below the normal solder ball 1, the presence or absence of the extra ball 1A can be easily confirmed by analyzing the level distribution by a well-known analysis technique.
[0030]
In the present invention, further various design changes are possible, and the detection of the remaining ball 1B shown in FIG. 6 may be performed by the camera 30 shown in FIG. 8 or the laser unit 32 shown in FIG. As the conductive balls, gold balls and the like can be used in addition to the solder balls.
[0031]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the extra ball which erroneously adhered to the mounting head can be detected, and only the conductive ball of the mounting head from which the extra ball was not detected can be mounted on a workpiece. Further, it is possible to easily detect the remaining balls remaining after the conductive balls are mounted on the work.
[Brief description of the drawings]
FIG. 1 is a side view of a conductive ball mounting apparatus according to a first embodiment of the present invention; FIG. 2 is an explanatory diagram of a conductive ball transfer operation of the conductive ball mounting apparatus according to a first embodiment of the present invention; FIG. 3 is an explanatory view of a conductive ball transfer operation of the conductive ball mounting device according to the first embodiment of the present invention. FIG. 4 is an extra ball detection of the conductive ball mounting device of the first embodiment of the present invention. FIG. 5 is an explanatory view of an extra ball detecting operation of the conductive ball mounting device according to the first embodiment of the present invention. FIG. 6 is a diagram illustrating a conductive ball mounting device according to the first embodiment of the present invention. FIG. 7 is an explanatory view of an operation of detecting a residual ball. FIG. 7 is a partially enlarged sectional view of a lower portion of a mounting head of a conductive ball mounting device according to a first embodiment of the present invention. FIG. FIG. 9 is a side view of a ball mounting device. FIG. 10 is a side view of a conductive ball mounting device according to a third embodiment of the present invention. FIG. 11 is a side view of a conductive ball mounting device according to a third embodiment of the present invention. Partial side view of [Description of symbols]
DESCRIPTION OF SYMBOLS 1 Solder ball 1A Extra ball 1B Remaining ball 2 Container 3 Base 4 Brush 10 Work 11 Clamper 14 Case 17 Light emitting element 18 Light receiving element 22 Mounting head 25 Suction hole 26 Moving table 30 Camera 31 Light source 32 Laser unit

Claims (5)

A work positioning unit, a conductive ball supply unit, a mounting head for holding a large number of conductive balls, and a moving unit for moving the mounting head between the work positioning unit and the conductive ball supply unit And an extra ball erroneously attached to the mounting head on the moving path of the mounting head and remaining on the lower surface of the mounting head without being mounted on a work. An apparatus for mounting a conductive ball, comprising a detecting means for detecting a remaining ball . The lower the suction holes of the mounting head is large number formed, and held by vacuum suction conductive balls on the suction holes, also said detecting means comprises a pre-Symbol light path is blocked by the extra ball and the remaining balls 2. The conductive ball mounting device according to claim 1, wherein the mounting device is an optical element. 2. The conductive ball mounting apparatus according to claim 1, wherein said detecting means comprises a light source for irradiating light to a lower surface of said mounting head, and a camera for observing the lower surface . 4. The conductive ball mounting apparatus according to claim 3, wherein a lower surface of the mounting head is darkened. 2. The conductive ball mounting apparatus according to claim 1, wherein said detecting means is a laser unit for detecting a level distribution on a lower surface of said mounting head.

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