JP3988158B2 - Ball suction head - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement of a ball suction head used in a ball mounting apparatus for mounting a solder ball, a solder bump or the like on a substrate or a wafer, and mainly a BGA (ball grid array) for mounting a solder ball on the entire surface of the wafer. This was developed mainly for the solder ball suction head in the solder ball mounting device.
[0002]
[Prior art]
In the BGA solder ball mounting apparatus, the ball suction head 1 for sucking the solder balls 7 is provided with a plurality of ball suction holes 2 for sucking the solder balls 7 on the lower surface as shown in FIG. The internal pressure of the inside is reduced by a vacuum means, so that the solder balls 7 are sucked and adsorbed from the solder ball supply tray 8. Conventionally, the adsorption amount of the solder balls 7 per one time of the ball adsorption head 1 was about 200, so there was no particular problem. However, in recent years, the solder balls 7 have been miniaturized and the mounting technology on the wafer has been developed. Along with this, the ball suction head 1 has attracted a large number (tens of thousands) of the solder balls 7.
[0003]
When the ball suction head 1 sucks a large number of solder balls 7 at the same time, or when the diameter of the ball suction hole 2 of the ball suction head 1 becomes large, the decompression means for decompressing the inside of the ball suction head 1 is large. However, there is a problem in terms of space and usability. Further, when the ball suction head 1 sucks a large number of solder balls 7 at the same time, there is a problem that the large number of solder balls 7 cannot be evenly sucked if the ability of the decompression means is reduced.
[0004]
[Problems to be solved by the invention]
In order to solve the above problems, the present invention firstly provides a ball suction head capable of uniformly sucking a ball with a small and low-capacity decompression means, and secondly, by dividing the suction area. Providing a ball adsorption head that can uniformly adsorb solder balls into ball adsorbing holes in a wider area than the capacity of the decompression means by adsorbing solder balls; Third, adsorbing by eliminating solder ball adsorption mistakes The purpose is to shorten the time.
[0005]
[Means for Solving the Problems]
In order to solve the above problems, the present invention is capable of closing a predetermined ball suction hole inside the ball suction head in a ball suction head in which a large number of ball suction holes are formed and connected to a decompression source by a suction passage. A mask and a switching means for closing and opening the ball suction hole by the mask are provided, and a detection means for detecting that the ball is sucked into a ball suction hole other than the ball suction hole closed by the mask is provided. Solder balls are adsorbed to the ball adsorbing head with the ball adsorbing holes closed, and the switching means is actuated in response to a command from the detecting means to open the ball adsorbing holes closed by the mask. Was configured to adsorb.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. The BGA solder ball mounting apparatus using the ball suction head 1 of the present invention is for sucking the solder balls 7 in the ball tray 8 storing the solder balls 7 and mounting the solder balls 7 on the wafer on the stage. It has a ball suction head 1 with a mask and suction detection means (for example, a pressure sensor 17). In other respects, the configuration may be the same as that of a conventional BGA solder ball mounting apparatus.
[0007]
As shown in FIGS. 1 and 3 to 5, a suction plate 3 in which a large number of ball suction holes 2 are formed is mounted on the lower surface of the ball suction head 1. In the embodiment of the drawing, the relationship between the ball adsorbing hole 2 and the solder ball 7 is schematically illustrated in order to clearly show the relationship, but the solder ball 7 is very small and the number of the ball adsorbing holes 2 reaches tens of thousands. In some cases.
[0008]
In the first embodiment shown in FIGS. 1 and 3 to 4, a movable mask 4 capable of closing and opening a predetermined ball suction hole 2 is provided inside the ball suction head 1. In this embodiment, since it is assumed that the solder balls 7 are mounted on the wafer, the ball suction holes 2 are arranged in a circular shape, and the shape of the mask 4 corresponds to a circular shape as shown in FIG. Further, half (50 percent) of the ball suction holes 2 formed in the suction plate 3 can be closed. By providing the mask 4 that can close half of the ball suction holes 2, the decompression means is a pump having half the required capacity compared to the case where the solder balls 7 are sucked into all the ball suction holes 2 at one time. Adsorption is possible.
[0009]
The mask 4 can accommodate a wafer of 4 inches to 8 inches, and the shape thereof is a shape like a four-blade propeller. However, if the mask 4 can close half of the ball suction holes 2, Well, it is not limited to this shape.
[0010]
The mask 4 is provided with an air cylinder 5 as a switching means (moving means for the mask 4) for closing and opening the ball suction hole 2. The mask 4 is attached to a rod 15 of an air cylinder 5 provided in the ball suction head 1. The operation of the air cylinder 5 causes a gap between the inner side surface of the suction plate 3 in the ball suction head 1 and its upper retracted position. It can be moved up and down.
[0011]
The switching means for the mask 4 can also be provided outside the ball suction head 1. That is, when the air cylinder 5 is used, the air cylinder 5 main body is provided on the outer top of the ball suction head 1, and only the rod 15 of the air cylinder 5 is inserted into the ball suction head 1, and the mask 4 is attached to the rod 15. is there.
[0012]
The ball suction head 1 is connected to a decompression source 16 by a suction passage 6 in order to suck the solder balls 7 from the ball tray 8 in which the solder balls 7 are stored, and in the direction of the central arrow in FIGS. 1 and 3 to 4 Has been sucked into. As the decompression source 16, a vacuum pump or a blower motor is used.
[0013]
Hereinafter, the operation of the ball suction head 1 of the first embodiment will be described. The ball suction head 1 is lowered onto the ball tray 8 in which the solder balls 7 are stored, and before the suction of the solder balls 7 is started, the mask 4 is lowered to the inner side surface of the suction plate 3 by the air cylinder 5 and brought into close contact. Then, the half of the ball suction holes 2 arranged on the suction plate 3 are closed. FIG. 1 shows this state.
[0014]
In this state, the air in the ball suction head 1 is sucked by the decompression source 16 connected to the suction passage 6, and the solder balls 7 are sucked and sucked into the ball suction holes 2 of the suction plate 3 not closed by the mask 4. FIG. 3 shows this state.
[0015]
Thereafter, whether or not the solder balls 7 are adsorbed to all the ball adsorbing holes 2 other than the ball adsorbing holes 2 closed by the mask 4 is detected by a detecting means (for example, a pressure sensor 17). A pressure sensor 17 is used as detection means for detecting whether or not all the ball suction holes 2 other than the ball suction holes 2 closed by the mask 4 have sucked the solder balls 7. A timer may be used instead of the pressure sensor 17.
[0016]
When all the ball suction holes 2 that are not closed by the mask 4 attract the solder balls 7, the pressure in the ball suction head 1 decreases (the degree of vacuum increases). When the predetermined pressure is reached, the switching means is operated by a command from the detection means. That is, the mask 4 is released from the suction plate 3 by the air cylinder 5 and retracted upward, and the solder balls 7 are sucked into the remaining ball suction holes 2. FIG. 4 shows this state. After adsorbing the solder balls 7 to all the ball adsorbing holes 2, the solder balls 7 are mounted on the wafer on the stage.
[0017]
The mask 4 in the first embodiment acts directly on the ball suction hole 2 and closes it, but the mask 4 in the present invention is a position where a suction force acts on the ball suction hole 2. As long as it can be set as a position where it does not act, it may act indirectly on the suction hole 2 as in the second embodiment shown in FIG.
[0018]
In the ball suction head 1 of the second embodiment, a punching metal 18 serving as a support plate, a support plate 19 composed of a fine mesh serving as a gas conduction member, and a solder ball 7 suction surface are provided on the lower surface of the ball suction head 1. The suction plate 3 provided with the fine ball suction holes 2 is integrally attached by a plate holder, and the mask 4 is disposed so as to contact the punching metal 18. The configuration of the mask 4, the moving means (switching means), the pressure sensor 17 and the like may be the same as in the first embodiment.
[0019]
As shown in FIG. 5, the punching metal 18 has a large number of gas conduction paths that do not correspond to the ball suction holes 2 of the suction plate 3, and forms a gas conduction path with a hole diameter of 3.8 millimeters and a pitch of 5 millimeters. Has been. The punching metal 18 supports the support plate 19 from an external force, and prevents the suction plate 3 from being bent by a negative pressure when the solder ball 7 is sucked, and the suction plate 3 from being bent by a reaction force from the wafer. Instead of the punching metal 18, a support member having a honeycomb structure may be used.
[0020]
As shown in FIG. 5, the support plate 19 is disposed between the suction plate 3 and the punching metal 18. The support plate 19 is formed by attaching a high-tensile resin net, which is a gas conduction 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 opened to a size including the suction area of the suction plate 3. It is something that is attached. A metal net or a porous material may be used instead of the high-tensile resin net. The support plate 19 is intended to create a layer in which air flows between the punching metal 18 and the suction plate 3 and to create a uniform ball suction state in the entire suction area of the suction plate 3.
[0021]
Also in the second embodiment, as in the first embodiment, the surface of the suction plate 3 is a ball suction surface, and a decompression chamber 20 connected to the decompression source 16 is provided on the back side thereof. In the second embodiment, first, the decompression chamber 20 is decompressed while the mask 4 is in contact with the punching metal 18, and the solder balls 7 are sucked from the solder ball supply tray 8 to cope with the decompression chamber 20. The solder ball 7 is adsorbed to a part of the many ball adsorbing holes 2, that is, the part of the ball adsorbing hole 2 where the suction force of the decompression chamber 20 is not blocked by the mask 4. When the pressure sensor 17 detects that the predetermined solder ball 7 is sucked, the mask 4 is raised, and the suction force acts on the ball suction hole 2 where the suction force has been shielded so far. The solder ball 7 is adsorbed to the ball suction hole 2.
[0022]
In the second embodiment as described above, the mask 4 does not directly close the ball suction hole 2 but closes a part of the gas conduction path of the punching metal 18. This also makes it possible to set a position where a suction force capable of attracting the solder ball 7 is applied and a position where the solder ball 7 is not applied. Therefore, the same effect as the first embodiment can be exhibited by the operation of the mask 4.
[0023]
In the first and second embodiments, one mask 4 is provided and the solder balls 7 are adsorbed to the ball suction holes 2 in two stages. However, a plurality of masks are provided so that they can be moved up and down independently. Alternatively, the solder balls 7 may be attracted to all the ball suction holes 2 in four stages.
[0024]
【The invention's effect】
Since the present invention is configured and operates as described above, the following effects are exhibited. First, a mask for setting a position at which a suction force is applied to a predetermined ball suction hole and a position at which the suction force is not applied to a predetermined ball suction hole is provided in the ball suction head. The ball adsorption efficiency of the holes can be increased. After this suction, the mask is removed and suction to the remaining ball suction holes is performed, so that the pressure reducing means can be smaller and lower capacity than the conventional one, and the ball suction that can perform uniform ball suction Could provide a head.
[0025]
Secondly, by providing a mask that applies a suction force only to a predetermined ball suction hole inside the ball suction head, and by dividing the suction area and sucking the solder balls, the solder of a wide area that exceeds the capacity of the decompression source In addition to providing a ball suction head capable of sucking balls, the suction efficiency was improved and the suction time was shortened.
[0026]
Third, the detection means for detecting that has adsorbed the ball to the ball suction holes provided, by a command from the detecting means, changing the position for applying a suction force of the ball suction holes by the mask to operate the switching means As a result, the above-described effects can be surely exhibited.
[Brief description of the drawings]
FIG. 1 is an explanatory sectional view showing a first embodiment of a ball suction head with a mask. FIG. 2 is a plan view of the mask. FIG. 3 is an explanatory sectional view showing a partial suction state of the first embodiment. FIG. 5 is a cross-sectional explanatory view showing a partial suction state of the second embodiment. FIG. 6 is an explanatory view showing a conventional ball suction head.
1. . . . . . 1. Ball suction head . . . . . 2. Ball suction hole . . . . . 3. Adsorption plate . . . . . Mask 5. . . . . . Air cylinder 6. . . . . . 6. suction passage . . . . . 7. Solder balls . . . . . Solder ball supply tray 15. . . . . . Rod 16. . . . . . Reduced pressure source 17. . . . . . Pressure sensor 18. . . . . . Punching metal19. . . . . . Support plate

Claims (1)

In a ball suction head in which a large number of ball suction holes are formed and connected to a decompression source by a suction passage, a mask capable of closing a predetermined ball suction hole inside the ball suction head, and closure of the ball suction hole by the mask And a switching means for opening and detecting means for detecting that the ball is adsorbed to a ball adsorbing hole other than the ball adsorbing hole closed by the mask , and adsorbing the ball while the predetermined ball adsorbing hole is closed by the mask. A feature is that the solder ball is adsorbed to the head, and the switching means is operated to open the closure of the ball adsorbing hole by the mask in accordance with a command from the detecting means so that the solder ball is adsorbed to all the ball adsorbing holes. A ball suction head in a ball mounting device.

Images