JPH07307343A - Bonding equipment for solder balls and bonding method - Google Patents

Abstract

PURPOSE:To provide bonding equipment for solder balls, which can judge whether solder balls in a vessel are surely vacuum-sucked and picked up by the suction holes of a suction head, and whether the picked up solder balls are surely transferred on a board or a chip, when the solder balls are bonded on the board or the chip and a bonding method. CONSTITUTION:Electrodes 70a which become electrically continuous or discontinuous according to whether solder balls exist are formed in the suction holes 4 of a suction head 3 which vacuum-sucks the solder balls. When the solder balls are vacuum-sucked in the suction holes 4, an electric current flows in the detector 73 of an electric circuit involving the electrodes 70a, and it is detected that the solder balls are vacuum-sucked.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solder ball bonding apparatus and a bonding method for bonding solder balls to be bumps to the surface of a work such as a chip or a substrate.

[0002]

2. Description of the Related Art It is known that solder balls are bonded to the surface of a chip or a substrate, and then the solder balls are heated to melt and solidify to form bumps (protruding electrodes).
FIG. 9 is a side view of a conventional solder ball bonding apparatus. Solder balls 1 that are the material of the bumps are stored in a container 2. Denoted at 3 is a suction head, which is driven by an ascending / descending means (not shown) to perform an ascending / descending operation so that the solder balls 1 are vacuum-sucked to the suction holes formed in the lower surface thereof and reciprocating means (not shown). Driven horizontally to move above the work such as the board 45 clamped and positioned by the clamper 44, and then moved up and down again to bring the solder ball 1 to a predetermined position on the board. It is designed to be bonded.

A large number of suction holes are formed on the lower surface of the suction head 3, and the solder balls 1 must be vacuum-sucked to all the suction holes and bonded to the substrate 45. Therefore, conventionally, a camera 7 is installed below the moving path of the suction head 3, and the lower surface of the suction head 3 is observed by the camera 7,
It is determined by image processing whether or not the solder balls 1 are vacuum-sucked in all the suction holes, and if OK, the suction head 3 moves directly above the substrate 45 to move the solder balls 1
Was bonded to the substrate 45.

[0004]

However, the above-mentioned conventional means has a problem that an erroneous determination is likely to occur due to the flicker and noise of the image of the camera 7. In addition, an extremely large number (generally, several tens or more) of the solder balls 1 are vacuum-adsorbed in many cases. Therefore, it takes a considerable time to inspect whether or not the solder balls 1 are vacuum-adsorbed in all the adsorption holes. However, there was a problem that work efficiency did not increase.

If the inspection result is NG, the suction head 3 is returned to the upper side of the container 2, and the raising / lowering operation is performed again there. Since this is not the case, a large amount of lost time is generated, and the work efficiency is not improved.
Furthermore, since the installation space for the camera 7 is required, the entire bonding apparatus becomes large, and the suction head 3 is attached to the substrate 4
Since the camera 7 must be moved above the camera 7 before it is moved above 5, the moving stroke of the suction head 3 becomes longer, and the takt time becomes longer, resulting in a poor work efficiency.

Further, all the solder balls picked up by the suction head are not always transferred onto the work, and some solder balls may remain attached to the suction holes of the suction head due to a transfer error. In that case, the work becomes a defective product in which the solder balls are missing. However, conventionally, there is no means for automatically detecting such a transfer error, so that a trouble associated with the transfer error or a defective work piece is likely to occur.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to solve the above conventional problems and provide a solder ball bonding apparatus and bonding method with high reliability in operation.
More specifically, it is an object of the present invention to provide a solder ball bonding apparatus and a bonding method, which are provided with means for accurately determining whether or not the suction head has made a solder ball pickup error. It is another object of the present invention to provide a solder ball bonding apparatus and a bonding method capable of easily determining whether or not all the solder balls picked up by a suction head have been bonded to a work without a transfer error.

[0008]

To this end, according to the present invention, an electrode which is electrically connected by a solder ball vacuum-adsorbed in a plurality of adsorption holes formed on the lower surface of the adsorption head is provided in the adsorption hole, and the conduction of the electrodes is achieved. A detection means for detecting non-conduction is provided.

[0009]

According to the above construction, it is possible to quickly detect whether or not the suction head has vacuum-sucked the solder balls in all the suction holes, and after confirming that there is no pickup error, the suction head moves toward the work such as the substrate. Therefore, the loss time can be eliminated, and the solder ball can be bonded to the work at a high speed and with good workability. Further, it can be easily determined whether or not all the solder balls vacuum-sucked by the suction head are transferred to the work and bonded.

[0010]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a side view of a solder ball bonding apparatus according to a first embodiment of the present invention, FIG. 2 is an electric circuit diagram wired at the bottom of a suction head provided in the solder ball bonding apparatus, and FIG. FIG. 6 is a partially enlarged cross-sectional view of the vicinity of a suction hole of a head.

In FIG. 1, reference numeral 11 denotes a container serving as a solder ball supply unit, in which the solder balls 1 are stored.
Reference numeral 12 denotes a base, which elastically supports the container 11 so that the container 11 can swing from the side and the bottom. Reference numeral 14 denotes a vibrator such as a piezoelectric element as an ultrasonic vibration means, which is mounted on the lower surface of the container 11. The vibrator 14 ultrasonically vibrates when a high-frequency voltage is applied, and the container 11 also ultrasonically vibrates, and the solder balls 1 stored therein are fluidized.
By adjusting the magnitude of this high-frequency voltage, the container 1
The magnitude of ultrasonic vibration 1 can be adjusted.

Reference numeral 15 denotes a solder ball supply device, which supplies the solder ball 1 to the container 11 through a pipe 16.
The container 11 is provided with a sensor for detecting the remaining amount of the solder ball 1 such as an optical sensor 47, and when it is detected that the amount of the solder ball 1 in the container 11 is low, the solder ball 1 is supplied. To do. Reference numeral 17 is a base of the supply device 15.

A large number of suction holes 4 for the solder balls 1 are formed on the lower surface of the suction head 3 in a matrisk shape (see also FIG. 2). The suction head 3 includes a support shaft 18 and a tube 19.
The solder ball 1 is vacuum-sucked to the suction holes 4 and is released from the vacuum suction state by being driven by the vacuum device 20.
Reference numeral 53 is a valve that opens and closes the suction passage of the tube 19, and 55 is a pressure sensor that detects vacuum pressure.

Reference numeral 21 is a holding block of the suction head 3, and the support shaft 18 of the suction head 3 is held by the holding block 21. Reference numeral 22 denotes a movable block, and two guide rails 23 are vertically arranged on the front surface of the movable block.
The holding block 21 is mounted on the guide rail 23 so as to be vertically movable. The nut 2 is provided on the side of the holding block 21.
4 and the nut 24 has a vertical feed screw 2
5 is screwed in. When the feed screw 25 is rotated by being driven by the motor 26 provided in the movable block 22, the holding block 21 and the suction head 3 move up and down. That is, the nut 24, the feed screw 25, and the motor 26 serve as an elevating unit that causes the suction head 3 to perform an elevating operation.

Reference numeral 30 denotes a movable table, and the movable block 22 is mounted on the movable table 30 slidably in the lateral direction. A motor 31 is attached to a side portion of the moving table 30, and when the motor 31 is driven, a feed screw 32 incorporated in the moving table 30 rotates, and the movable block 22 moves laterally along the feed screw 32. Move back and forth. That is, the moving table 30 serves as a means for reciprocating the suction head 3.

Numeral 40 is a positioning portion, which includes a base 41 and
The X table 42 and the Y table 43 are stacked. A clamper 44 is provided on the Y table 43, and the substrate 45 is clamped from the left and right to be positioned. The suction head 3 is moved by the moving table 30 into the container 1
It reciprocates between 1 and the positioning unit 40.

Next, with reference to FIGS. 2 and 3, a description will be given of the means for detecting the solder balls 1 vacuum-sucked in the suction holes 4. Two electrodes 70a are provided on the edges of all the adsorption holes 4, respectively. If the suction holes 4 vacuum-suck the solder balls 1, the electrodes 70a, 70a are in electrical contact with the solder balls 1 and are electrically non-conductive unless the solder balls 1 are vacuum-sucked. In the first embodiment of the invention, as shown in FIG. 2, each of the columns A, B,
A series circuit is configured for each of the four adsorption holes 4 of C and D, and independent switches 71a, 71b,
The power source 72 and the detector 73 are connected by 71c and 71d. In FIG. 2, the electrode 70a and the electric circuit are drawn in a model for easy understanding.

If the solder balls 1 are all vacuum-adsorbed in the four adsorption holes 4 in the row A, when the switch 71a is closed, a current flows in the closed loop including the row A and is detected by the detector 73. It can be seen that the solder balls 1 are vacuum-sucked in the holes 4. If no current is detected, A
It can be seen that at least one of the four suction holes 4 in the row does not vacuum-suck the solder ball 1. Similarly, B
The switches 71 for the columns C, D
By sequentially opening and closing b, 71c, 71d, the presence or absence of vacuum suction of the solder ball 1 can be determined.

The solder ball bonding apparatus is constructed as described above. Next, the overall operation will be described.
In FIG. 1, when the motor 26 rotates forward, the suction head 3 moves down. At that time, when the vibrator 14 is driven, the container 11 is ultrasonically vibrated, and the solder balls 1 stored therein flow. Then, the suction head 3 is lowered, so that the solder ball 1 is vacuum-sucked to the suction hole 4. Meanwhile, the switches 71a and 71 shown in FIG.
b, 71c, 71d are sequentially opened and closed, and the detector 73 detects the current. If a current flows through all the circuits in each of the columns A, B, C, D, it is determined that the solder balls 1 are vacuum-sucked in all the suction holes 4. Such a determination can be easily made by a well-known processing technique of a computer. Then, the motor 26 rotates in the reverse direction, so that the suction head 3
Goes up and the solder ball 1 is picked up.

Next, in FIG. 1, when the motor 31 rotates in the forward direction, the suction head 3 moves above the substrate 45, and the motor 26 rotates in the forward direction, so that the suction head 3 descends and the solder ball 1 moves. Are mounted on the upper surface of the substrate 45. Next, the vacuum suction state by the vacuum device 20 is released, the suction head 3 rises, and the motor 31 rotates in the reverse direction, whereby the suction head 3 returns to above the container 11. Flux is previously applied to the upper surface of the substrate 45 by means not shown, and the solder balls 1 are bonded to the substrate 45 by the adhesive force of this flux.

By repeating the above operation, the solder balls 1 are bonded to the upper surface of the substrate 45 one after another. The bonded solder ball 1 is heated and melted in a later process to form a bump. The switches 71a to 7
The timing of detecting the presence or absence of the solder ball 1 by opening and closing 1d may be any time between the pickup operation and the time of transferring and bonding to the substrate 45 and bonding, but if it is performed during the pickup operation. Since it is possible to quickly detect a pickup error in real time, it is desirable to perform it during the pick-up operation. Furthermore, it is desirable to start the raising operation of the suction head 4 or the movement operation to the substrate 45 after confirming that all the suction holes 4 have vacuum-sucked the solder balls 1. This is not preferable. It is possible to prevent the generation of the non-defective substrate 45.

FIG. 4 is an electric circuit diagram wired at the bottom of the suction head provided in the solder ball bonding apparatus of the second embodiment of the present invention. In the second embodiment of the present invention, the electrode 70a provided in the suction hole 4 of the suction head 3, the switch 71, the power source 72, and the detector 73 are all connected in series. Therefore, if any one of the suction holes 4 of the total 16 makes a pickup error, the electric circuit is not closed, so that no current flows through the detector 73, and it is possible to detect that a pickup error has occurred.

FIG. 5 is an electric circuit diagram wired at the bottom of the suction head provided in the solder ball bonding apparatus of the third embodiment of the present invention. As will be described later, in this electric circuit, all (16 in this embodiment) solder balls 1 picked up by the suction head 3 by vacuum suction are connected to the substrate 4.
5 is an electric circuit for determining whether or not all the data have been transferred without any transfer error after the transfer operation. In the third embodiment of the present invention, the electrodes 70b are provided on both sides of the adsorption hole 4. Further, as shown in the drawing, a parallel circuit is formed for each of the columns A, B, C, D. The parallel circuit of each column A, B, C, D is connected to the power source 72 and the detector 73 via the switches 71a to 71d, respectively. Therefore, in the parallel circuit of each of the columns A, B, C, D, if even one solder ball 1 is vacuum-sucked to any suction hole 4,
A current flows and can be detected by the detector 73.

In this electric circuit, the suction head 3 is mounted on the substrate 45.
It is operated after the transfer operation of the solder ball 1 to and from. That is, in FIG. 1, the suction head 3 that picks up the solder ball 1 by vacuum suction moves to the upper side of the substrate 45, and then performs the raising / lowering operation again to hold the solder ball 1 on the substrate 4.
However, in this case, not all of the solder balls 1 are transferred from the suction head 3 to the substrate 45, and the solder balls 1 may remain attached to the suction head 3. Then, the substrate 45 becomes a defective product in which the solder balls 1 are partially missing.

Therefore, in the third embodiment of the present invention, after the suction head 3 carries out the transfer operation of the solder balls 1 on the substrate 45, the switches 71a-71b are opened and closed in order. In any case, if the detector 73 does not detect the current, it can be seen that all the solder balls 1 have been transferred to the substrate 45. If the detector 73 detects a current, it can be seen that at least one solder ball 1 remains attached to any of the suction holes 4 and there is a transfer error. In FIG. 5, the solder balls 1 in the row C shown by the chain line are attracted by the suction holes 4 due to a transfer error.
The one that is still attached to is shown.

Various recovery methods can be considered in this case. That is, for example, in this case, the suction head 3 is again moved up and down to remove the remaining solder balls 1 from the substrate 4.
Reprint to 5. This recovery operation may be repeated any number of times. Further, in that case, air may be pressure-fed from the vacuum device 20 to the suction head 3, and the solder ball 1 may be forcibly separated from the suction hole 4 by the air pressure and transferred onto the substrate 45. Such switching of the air flow of the vacuum device 20 can be easily performed by a known mechanism. If the transfer error is not eliminated even after repeating a predetermined number of times, the operation of the apparatus is stopped and the operator is notified of that fact by a notification means such as a buzzer. Therefore, the operator removes the solder balls 1 remaining on the suction head 3 by using an operator such as tweezers, and manually mounts the solder balls 1 on the missing portions of the substrate 45.

FIG. 6 is an electric circuit diagram wired at the bottom of the suction head provided in the solder ball bonding apparatus of the fourth embodiment of the present invention. The fourth embodiment differs from the third embodiment in that the two switches 71a and 71b, the power supply 72, and the detector 73 are circuits independent of the electric circuit on the suction head 3 side. In the fourth embodiment, the switches 71a and 71b are electrically scanned in the direction of the arrow so that the contacts a, b, c, d, and
The column A, B, C, D is continuously opened and closed by sequentially contacting e, and whether or not a current flows is detected by the detector 73, and the same effect as the third embodiment is obtained. can get.

If the electric circuit for detecting a pickup error shown in FIGS. 2 and 4 and the electric circuit for detecting a transfer error shown in FIGS. 5 and 6 are incorporated into the suction head 3, a pickup error will occur. A transfer error can be detected together. Next, an example will be described.

FIG. 7 is an electric circuit diagram wired at the bottom of the suction head provided in the solder ball bonding apparatus of the fifth embodiment of the present invention. The suction holes 4 are provided with a pair of first electrodes 70a for detecting a suction error and a pair of second electrodes 70b for detecting a mounting error. In addition, the series circuit for detecting the suction error includes the first switch group S for circuit interruption.
W1 is provided, and a second switch group SW2 for circuit interruption is provided in the parallel circuit for detection of mounting error.

Here, if the suction error is detected, the control unit 8
When the first switch group SW1 is turned on (closed) and the second switch group SW2 is turned off (open) by 0, a circuit equivalent to that in FIG. 4 is obtained. If a mounting error is detected, the first switch group SW1 is turned off and the second switch group SW2 is turned on.
Then, the circuit becomes equivalent to that in FIG.

FIG. 8 is an electric circuit diagram wired at the bottom of the suction head provided in the solder ball bonding apparatus of the sixth embodiment of the present invention. In the sixth embodiment, a pair of electrodes 70c are arranged in the adsorption holes 4 and are connected by one parallel circuit. This parallel circuit has a second switch group SW
2 are arranged. Turn off the second switch group SW2
When set to (open) and the first switch SW1 is turned on (closed), one series circuit is formed.

Therefore, in the case of detection of an adsorption error, the second switch group SW2 is turned off and the first switch SW1 is turned on.
Set to N. In the case of a mounting error detection, the second switch group SW2 is turned on and the first switch SW1 is turned off. When the suction holes 4 are odd, the first switch SW
1 is omitted.

As is clear from the embodiments described above, various concrete configurations of the present invention are conceivable.
The point is that an electrode that conducts with a solder ball is provided in the suction hole of the suction head to determine the presence or absence of the solder ball. Further, in each of the above embodiments, the substrate has been described as an example of the work, but the work may be a chip that is a flip chip.

[0034]

As described above, according to the present invention, it is possible to electrically check whether or not the suction head picks up a solder ball and whether or not the picked up solder ball is transferred to a work such as a substrate. Can be accurately determined. Further, it becomes possible to appropriately perform recovery when a pickup error or a transfer error occurs, and thus it is possible to realize a highly reliable solder ball bonding apparatus or bonding method.

[Brief description of drawings]

FIG. 1 is a side view of a solder ball bonding apparatus according to a first embodiment of the present invention.

FIG. 2 is an electric circuit diagram wired at the bottom of a suction head provided in the solder ball bonding apparatus of the first embodiment of the present invention.

FIG. 3 is a partially enlarged sectional view of the vicinity of a suction hole of a suction head provided in the solder ball bonding apparatus of the first embodiment of the present invention.

FIG. 4 is an electric circuit diagram wired at the bottom of the suction head provided in the solder ball bonding apparatus of the second embodiment of the present invention.

FIG. 5 is an electric circuit diagram wired at the bottom of the suction head provided in the solder ball bonding apparatus of the third embodiment of the present invention.

FIG. 6 is an electrical circuit diagram wired at the bottom of a suction head provided in the solder ball bonding apparatus of the fourth embodiment of the present invention.

FIG. 7 is an electric circuit diagram wired at the bottom of the suction head provided in the solder ball bonding apparatus of the fifth embodiment of the present invention.

FIG. 8 is an electric circuit diagram wired at the bottom of the suction head provided in the solder ball bonding apparatus of the sixth embodiment of the present invention.

FIG. 9 is a side view of a conventional solder ball bonding apparatus.

[Explanation of symbols]

 1 Solder Ball 2 Container 3 Suction Head 4 Suction Hole 24 Nut 25 Feed Screw 26 Motor 30 Moving Table 40 Positioning Part 45 Substrate (Work) 70a, 70b, 70c Electrode 71, 71a, 71b, 71c, 71d Switch 73 Detector

Claims (5)

[Claims] 1. A solder ball bonding apparatus for vacuum-sucking a solder ball to a plurality of suction holes formed in a lower surface of a suction head to bond to a work, the solder ball being vacuum-sucked to the suction hole. A solder ball bonding apparatus characterized in that a pair of electrodes that come into contact with each other is provided in the suction hole, and a detection means is provided for applying a current to the electrodes to detect conduction / non-conduction of the current. 2. The suction head moves up and down above the solder ball supply section to vacuum-suck the solder balls into a plurality of suction holes formed in the lower surface of the suction head and then pick up the solder balls. A solder ball bonding method for transferring the solder balls to the work by moving the suction head above the work positioned in the positioning portion, and performing the elevating operation again there. Bonding the solder balls to the work after detecting whether or not the pair of electrodes provided respectively contact the solder balls by the detection means and confirming that the solder balls have contacted the electrodes of all the suction holes. A solder ball bonding method characterized by: 3. The solder ball bonding method according to claim 2, wherein the detection by the detection means is performed when the suction head moves up and down to pick up a solder ball. 4. A suction head is raised and lowered above a solder ball supply portion to vacuum-suck and pick up solder balls in a plurality of suction holes formed in the lower surface of the suction head, and then picked up. A solder ball bonding method for transferring the solder balls to the work by moving the suction head above the work positioned in the positioning part and performing the elevating operation again there. After the solder balls are transferred to the work by moving up and down above, the detecting means detects whether or not the solder balls are in contact with the pair of electrodes provided in the suction holes. A solder ball bonding method, characterized in that if a contact is detected, it is determined that a transfer error has occurred. 5. The solder ball bonding according to claim 2, wherein the solder ball is detected by passing a current through the pair of electrodes to detect conduction / non-conduction of the current. Method.