JPH11312701A - Solder ball-mounting device to wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the useless solder balls, by controlling the up and down movements of a plurality of mounting heads based on the chip-arrangement pattern on a wafer, and providing the solder holes on the wafer. SOLUTION: At a mounting unit part 4, a plurality of mounting heads 14 and 15, wherein the aligning patterns of solder-ball sucking holes are different, are provided. Then, the mounting unit part 4 such as this is moved on a wafer stage. Solder balls 16 are mounted on the standby wafer from the both mounting heads 14 and 15. At this time, the position of the defective chip on the wafer is judged. At the position where four balls can be mounted simultaneously, the mounting is performed at a multiple-chip head 15. At the position of the fraction, the mounting is performed at the single-chip head 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an apparatus for mounting micro solder balls for bonding used on a semiconductor chip. Is a device for directly mounting solder balls on a semiconductor chip.

[0002]

2. Description of the Related Art Conventionally, a plating method, a printing method, and the like have been mainly used for forming bumps in a wafer state. In the case of the plating method or the printing method, bumps are formed on a wafer at one time, so that bumps are formed on all defective chips.

Conventionally, there has also been an apparatus for mounting a solder ball for bonding on a semiconductor chip. However, in the conventional solder ball mounting apparatus, since the semiconductor chip is transported by a frame having a single unit or a plurality of units,
It has a single semiconductor chip alone or a number of mount heads corresponding to the number of semiconductor chips in the transport frame.

However, with the recent spread of the use of solder balls, there has been a demand for improved production, and the need for mounting solder balls directly on chips on a wafer has been increasing. Since many identical or similar chips are arranged on a wafer, there is a possibility that the chips can be mounted on several chips at one time. Mounting these chips one by one would be inefficient. For this reason, Patent No. 2657
Attempts have been made to mount, for example, four adjacent chips on a wafer at once, as in the apparatus described in the '356 patent.

However, as shown in FIG. 4, defective chips 3 (chips marked X in FIG. 4) exist on the wafer 1 in addition to the non-defective chips 2, and the method described in Japanese Patent No. 2657356 is used. In this case, the solder balls are also mounted on the defective chips 3, resulting in waste of the solder balls. In the case where the number of defective chips 3 is small as in the wafer shown in FIG.

[0006]

SUMMARY OF THE INVENTION The present invention cancels the mounting of solder balls on defective chips 3 on a wafer 1, prevents waste of solder balls, and simultaneously solders a plurality of chips on a wafer. An object of the present invention is to provide a solder ball mounting apparatus for mounting a ball on a wafer, which can mount a ball.

[0007]

In order to solve the above-mentioned problems, the present invention has a plurality of mount heads having different arrangement patterns of solder ball suction holes, and holds the plurality of mount heads individually so as to be able to move up and down. Controlling the elevation of the plurality of mount heads based on the chip arrangement pattern on the wafer or the chip arrangement pattern on the wafer and the defective chip position data to mount the solder balls on the wafer for mounting the solder balls on the chips on the wafer Provide equipment.

[0008]

Embodiments of the present invention will be described below with reference to the illustrated embodiments. FIG. 1 is a schematic plan view showing one embodiment of a solder ball mounting device according to the present invention. The solder ball mounting device includes a mounting unit 4 having two mounting heads that move up and down independently, a ball supply unit 5, and a ball. Suction confirmation unit 6, ball discharge box 7, wafer stage 8, wafer magazine 9, 1
0, drive devices 11, 12, and 13 for driving the mount head and the mount unit.

The mount unit 4 is provided with a plurality of mount heads having different arrangement patterns of the solder ball suction holes. The mount unit 4 shown in FIG. 2 has two mount heads 14 and 15, and a single-chip head 14 that can carry and mount only one chip of solder ball, In the embodiment shown in FIG. 2, a multi-chip head 15 capable of carrying and mounting solder balls for four chips is prepared. Focusing on the arrangement pattern of the solder ball suction holes of the mount heads 14 and 15, the multi-chip head 15 has four arrangement patterns of the single-chip heads 14.

In the solder ball mounting device, the horizontal movement of both mount heads 14 and 15 is controlled by the drive device 11.
Thus, the movement is performed integrally with the movement of the mount unit 4. First, the mount unit 4 moves above the ball supply unit 5 and descends to suck the solder balls 16 through the suction holes formed on the lower surfaces of the mount heads 14 and 15.

The lifting and lowering of the mount heads 14 and 15 are performed by cylinders which are driving devices 12 and 13 which are individually operable. The suction of the solder balls 16 is performed by a separate vacuum suction device (not shown). This work is performed by using the single-chip head 14 and the multi-chip head 15
Are sequentially performed with the two mount heads.

Next, the mount unit 4 moves to the ball suction confirming unit 6 to check for a leak of the solder balls 16 and for the extraly sucked solder balls 16. This operation is also performed sequentially with the two mount heads of the single-chip head 14 and the multi-chip head 15. If there is a suction leak, the process returns to the ball supply unit 5 again to perform the suction operation. If there is an excess, it moves to the ball discharge box 7 and discharges it.

Thereafter, both mount heads 14 and 15 move to wafer stage 8 shown in FIG. On the wafer stage 8, the wafer 1 is positioned in advance and is on standby. The wafer 1 is taken out of the wafer magazine 9 in which the unmounted wafer 1 is stored, applied with a flux by a flux supply device (not shown), and supplied to the wafer stage 8.

An image of the entire wafer 1 is captured on the wafer stage 8 by an image recognition camera (not shown), and positioning of the wafer 1 and confirmation of the positions of the non-defective chips 2 and the defective chips 3 in the wafer 1 are performed. At this time, without using an image recognition camera, the position data of the defective chip 3 recognized in the wafer inspection in the previous process can be transmitted and used.

From the position data of the non-defective chips 2 and the defective chips 3 on the wafer 1, a pattern that can skip the defective chips 3 on the wafer 1 and efficiently mount the solder balls 16 is calculated. For example, it is determined which location uses the multi-chip head 15 and which location uses the single-chip head 14. At this time, the number of uses of the multi-chip head 15 is substituted for the variable M, and the number of uses of the single-chip head 14 is substituted for the variable S.

The mount unit 4 includes a wafer stage 8
The solder balls 16 are mounted on the wafer 1 that has moved upward and are on standby from the mount heads 14 and 15. At this time, judging from the position of the defective chip 3 on the wafer 1,
The mounting is performed by the multi-chip head 15 at the position where four chips can be mounted at the same time, and the single-chip head 14 is mounted at the fractional position.

FIG. 6 shows a specific example of the mount. FIG.
In FIG. 1, one unit is divided by a line which crosses the wafer 1 vertically and horizontally, and X is a defective chip 3 and the other part is a non-defective chip 2 on which a solder ball is to be mounted.
It is. In the non-defective chip 2, four square portions connecting four adjacent ones are portions indicating positions at which four can be simultaneously mounted, and a portion indicated by a circle is a fractional portion. The portion indicated by a rectangle is the multi-chip head 15
, And the portion indicated by ○ is mounted by the single-chip head 14.

In this embodiment, a case will be described in which a large number of defective chips 3 are present to some extent. However, defective chips 3 (parts indicated by x symbols in FIG. 5) are present as in the wafer 1 shown in FIG. In the case of a small number, that is, when the waste of the solder balls is negligible, the ball mounting can be performed based on only the chip arrangement pattern as shown in FIG. 7 without taking in the position data of the defective chip 3. .

The movement between the chips to be mounted on the wafer 1, that is, the movement on the plane (movement to the X axis, Y axis, and θ axis) is performed on the XY table 17 and the rotary table 18 of the wafer stage 8. Do it.

Wafer 1 on which solder balls 16 are mounted
Is moved to and stored in a wafer magazine 10 for storing the mounted wafer 1.

Hereinafter, a control example of this embodiment will be described. The first control example is a case of mounting with the single-chip head 14 after mounting with the multi-chip head 15, and will be described with reference to FIG. The solder ball mounting device is started, and defective chip 3 on wafer 1
Fetch the position data. The position data of the defective chip 3 on the wafer 1 may be a data at the time of the inspection in the previous process, which may be collectively and externally input, or the defective data position data may be fetched by an image recognition camera in the present apparatus.

A defective chip 3 on the wafer 1 is skipped and an optimum ball mounting order is calculated. The number of mounts by the multi-chip head 15 is substituted for a variable M, and the number of mounts of the single-chip head 14 is substituted for a variable S. Here, the ball mounting operation starts, and first, the ball mounting by the multi-chip head 15 is performed.

In one mounting operation of the multi-chip head 15, the calculation of M = M-1 is performed, and it is checked whether M = 0. Unless M = 0, ball mounting by the multi-chip head 15 is performed. When the number of times assigned to the variable M ends and M = 0 holds,
The operation shifts to ball mounting using the single-chip head 14. Also here, a check is made as to whether or not S = 0 every time the single-chip head 14 is mounted. If S = 0, ball mounting is performed by the single-chip head 14. When S = 0 is satisfied, the mounting operation ends.

In the second control example, the multi-chip head 15
And mounting using the single chip head 14 at the same time, which will be described with reference to FIG. The process from the start to fetching the position data of the defective chip 3 on the wafer 1, skipping the defective chip 3 and calculating the optimum ball mounting order, and starting the ball mounting operation is the same as in the first control example. is there.

In the ball mounting operation, first, after the ball mounting by the first multi-chip head 15 is completed, the calculation of M = M−1 is performed, and then the ball mounting by the single-chip head 14 is performed. S
= S-1 is calculated. At this time, whether M = 0 or not, S = 0
The multi-chip head 15 and the single-chip head 1 are again checked if they are NO.
The ball mounting at 4 is performed. Note that the calculation of M = M-1 and S = S-1 is performed for each mount.

When ball mounting is performed several times by both mounting heads 14 and 15 and M = 0 is established and S = 0 is not established, the single chip head 14 is maintained until S = 0 is established. Ball mounting is performed. Thereafter, when S = 0 is established, the mounting ends.

In the above example, when the number of mountings with the single-chip head 14 is large, and when the number of mountings with the multi-chip head 15 is large, M = 0 after some mountings. S = 0 is not established, and the ball mounting is performed only by the multi-chip head 15 until M = 0 is established. When M = 0 is established, the mounting ends.

When the number of times of mounting with the single-chip head 14 and the number of times of mounting with the multi-chip head 15 are the same, mounting with the multi-chip head 15 and mounting with the single-chip head 14 were performed alternately. Thereafter, when M = 0 and S = 0 are established, the ball mounting ends. In any case, when both M = 0 and S = 0 are established, the ball mounting ends.

[0029]

According to the present invention, first, since a plurality of mount heads can simultaneously mount solder balls on a plurality of chips on a wafer, the time required for solder ball mounting is reduced. Decrease.

Secondly, a plurality of mount heads having different arrangement patterns of the solder ball suction holes are provided, each of which is independently movably held up and down, and a chip arrangement pattern on a wafer or a chip on a wafer is held. Since the elevation of the plurality of mount heads is controlled based on the arrangement pattern and the defective chip position data, ball mounting on the defective chip can be avoided, and waste of solder balls can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic plan view showing an embodiment of a solder ball mounting device.

FIG. 2 is a perspective view of a mount unit.

FIG. 3 is a perspective view of a wafer stage.

FIG. 4 is an explanatory plan view of a wafer having a high ratio of defective chips;

FIG. 5 is an explanatory plan view of a wafer having a low ratio of defective chips;

FIG. 6 is an explanatory plan view showing an example of a mount on a wafer.

FIG. 7 is an explanatory plan view showing another example of mounting on a wafer.

FIG. 8 is an explanatory diagram showing a first control example.

FIG. 9 is an explanatory diagram showing a second control example.

[Explanation of symbols]

 1. . . . . . . . . . Wafer 2. . . . . . . . . . Good chip 3. . . . . . . . . . Defective chip 4. . . . . . . . . . Mount unit 5. . . . . . . . . . Ball supply unit 6. . . . . . . . . . 6. Ball suction confirmation unit . . . . . . . . . 7. Ball discharge box . . . . . . . . . Wafer stage 9, 10. . . . . . . Wafer magazine 11, 12, 13. . . Drive device 14. . . . . . . . . Head for single chip 15. . . . . . . . . Multi-chip head 16. . . . . . . . . Solder ball 17. . . . . . . . . XY table 18. . . . . . . . . Rotary table

Claims (1)

[Claims] A plurality of mount heads having different arrangement patterns of solder ball suction holes, each of the plurality of mount heads being independently held in a vertically movable manner, and a chip arrangement pattern on a wafer or a chip arrangement pattern on a wafer. A solder ball mounting apparatus for mounting a solder ball on a chip on a wafer by controlling the elevation of the plurality of mounting heads based on the defective chip position data.