JP2002134540A - Method and equipment for mounting and arranging conductive balls - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conducive ball arranging/transferring/mounting method by which arrangement failure is removed accurately and effectively. SOLUTION: After vacuum-arranging conductive balls B on the arranging plate 20, the conductive balls B are mounted in batch to the electrode which is a mounting object to which balls B are to be installed. When arranging the balls B on the arranging plate 20, the ball arrangement failure positions are detected and the conductive balls B placed in an area including the arrangement failure positions are removed in line or area state. Balls B are removed in line or area state using a gas flow. The gas flow is an air flow or an inert gas flow.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for collectively holding fine conductive balls on an array board and arraying and mounting them on electrodes of an electronic component such as a printed circuit board or a chip. .

[0002]

2. Description of the Related Art In recent years, ball bumps using minute metal spheres have been used for electrical connection of semiconductor chips. By using the ball bump, various advantages such as miniaturization of the package and increase in the number of pins can be obtained. Such a bump forming technique using minute metal balls is described in, for example, Japanese Patent Application Laid-Open No. 7-153765.

In the bump forming method described in the above publication, a metal ball group for at least one semiconductor chip is sucked and held. Then, in order to suction-hold a plurality of metal ball groups, a ball array plate having suction holes formed at all positions corresponding to the bump formation positions on the semiconductor chip is used. After adsorbing and holding the minute metal spheres on the ball array plate, the ball array plate is transported to a mounting stage and mounted on a mounting portion.

According to this method, uniformly formed minute metal balls can be collectively mounted at the bump formation positions, so that ball bumps with little variation and high shape accuracy can be formed easily and efficiently. it can. By the way, recently, the miniaturization of semiconductor devices has been increasingly advanced, and the wiring pitch of the electrodes has become extremely small. For this reason, metal balls used for forming ball bumps on electrodes have become extremely fine as the wiring pitch of the electrodes becomes finer.

In such a situation, arranging one semiconductor chip (in a unit of a chip) has many disadvantages in terms of cost and time because the number of steps is increased. Therefore, before the wafer is cut into individual chips, that is, before the dicing process is performed, ball bumps are formed on all the electrodes corresponding to a plurality of chips on the wafer.

[0006]

In this type of ball array mounting technology, two or more balls may be sucked into one suction hole of the ball array plate, resulting in a defective suction array. For example, in the method or apparatus for transferring a ball-shaped bump described in Japanese Patent Application Laid-Open No. 12-12593, the gas flow is adjusted so as to remove only the excess balls having a defective suction arrangement without dropping the normally sucked balls. (Spray or suction) is set, and the entire area of the ball array surface is scanned.

However, when ball bumps are formed on all the electrodes on a wafer on which a plurality of semiconductor chips are formed at once, that is, on a wafer basis, the total number of balls may reach hundreds of thousands. There is a case where various types of defective arrangement such as a difference in arrangement state of balls and a mixture of dust and irregularly shaped balls are mixed as compared with a chip unit. Therefore, there is a problem that the surplus balls cannot be completely removed by simply scanning the entire area of the ball arrangement surface.

[0008] In addition, there is a case where misaligned balls are firmly adhered to such an extent that they cannot be removed with the gas setting according to this publication. Can not. Furthermore, in order to remove these misaligned portions, all the balls once adsorbed, including the balls that have been properly adsorbed, are discarded and re-adsorbed.

However, when the balls are collectively sucked on a wafer basis, the rate of occurrence of an array defect becomes higher in each stage than on a chip basis. For this reason, even if all the attracted balls are discarded and re-adsorbed, defective alignment occurs again, and the defective alignment portion may not be able to be removed.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a method and an apparatus for mounting a conductive ball array capable of efficiently and accurately removing an alignment defect.

[0011]

According to the conductive ball array mounting method of the present invention, the conductive balls are suction-arranged on an array plate, and then the conductive balls are mounted on an electrode of a mounting object on which the balls are to be mounted. A ball array mounting method for mounting the balls collectively, wherein when arranging the balls on the array plate, a ball array defective portion is detected, and the conductive balls in a region including the array defective portion are formed in a line shape or an area shape. It has a step of removing.

Further, in the conductive ball array mounting method of the present invention, the conductive balls are removed in a line shape or an area shape by a gas flow. In the conductive ball array mounting method according to the present invention, the gas flow is an air flow or an inert gas flow. Further, in the conductive ball array mounting method of the present invention, the conductive ball array is removed in a line shape or an area shape by suction.

In the conductive ball array mounting apparatus of the present invention, after the conductive balls are suction-arranged on an array plate, the conductive balls are mounted collectively on an electrode of a mounting object on which the balls are to be mounted. A ball array mounting device, wherein when arranging the balls on the array plate, a ball removing mechanism for removing conductive balls in a region including a defective ball array site in a line shape or an area shape. .

Further, in the conductive ball array mounting apparatus according to the present invention, the ball removing mechanism includes a gas ejection means for removing the conductive balls by a gas flow. In the conductive ball array mounting device according to the present invention, the ball removing mechanism includes a suction unit that removes the conductive ball by suction.

According to the present invention, a defective ball arrangement is detected, and the conductive balls in the region including the defective arrangement are removed in a line or area shape, thereby efficiently and accurately removing the defective arrangement. can do.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the method and apparatus for mounting a conductive ball array according to the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of the apparatus of the present invention. In this embodiment, conductive balls are collectively mounted on an electrode portion of a semiconductor substrate or a wafer. FIG.
In, the wafer W is transferred to the ball mounting stage 10 along a wafer transfer path in a direction (X direction) perpendicular to the paper surface, and waits at a predetermined position.

Here, in the embodiment of the present invention, the wafer W
Is intended for those having a size of 4 inches or more. According to the wafer W, a plurality of semiconductor chips C (individual square portions) to be formed as shown in FIG. 3 can be obtained, and the electrode portion of each semiconductor chip C has the device of the present invention as described later. , A plurality of conductive balls are mounted.
In FIG. 3, the conductive balls are shown in a simplified manner, but the number of conductive balls used in the entire semiconductor chip C is several hundred thousand. According to the present invention, such an extremely large number of conductive balls are collectively mounted on the wafer W.

As shown in FIG. 1, a guide or guide rail 11 is provided along a direction (Y direction) orthogonal to the wafer transfer path.
The ball mounting head 12 movable in the −Z direction is supported. The ball mounting head 12 suction-arranges the conductive balls B on an array plate and mounts the conductive balls B on the electrode portions of the semiconductor chips C formed on the wafer W at a time, as described later.

The ball supply device 1 is positioned at one end of the guide rail 11 below the ball mounting head 12.
3 are arranged. The ball supply device 13 is a ball storage container (ball tray) 1 that stores a considerable amount of conductive balls B.
4 and a vibrator 15 that vibrates the ball tray 14 to cause the conductive balls B to jump in the ball tray 14.

Between the ball supply device 13 and the ball mounting stage 10, an arrangement failure ball removing mechanism 16 and an arrangement inspection camera 17 are arranged. The ball removing mechanism 16 includes a nozzle 18 (see FIG. 4, FIG. 6, and FIG. 7) for removing the misaligned ball in the ball mounting head 12 by suction or gas blowing. The nozzle 18 is configured as a suction unit or a gas ejection unit that removes the conductive balls B in a region including the defective ball arrangement portion in a line shape or an area shape.

The arrangement inspection camera 17 inspects the ball arrangement defect in the ball mounting head 12 by inspecting the arrangement status immediately after the ball is adsorbed, inspecting the entire arrangement surface after removing the error ball, and re-adsorbing. A later inspection of the arrangement state, an inspection of the balls remaining in the ball mounting head 12 after the balls are mounted, and the like are performed.

The ball mounting head 12 reciprocates between the ball supply device 13 and the ball mounting stage 10.
As shown in FIG. 2, a suction mechanism 19 connected to a negative pressure or vacuum source is provided.
Are arranged in a suction arrangement. The array plate 20 has suction holes 20a corresponding to the electrode portions of the plurality of semiconductor chips C on the wafer W. Then, by the suction mechanism 19, the conductive balls B jumping in the ball tray 14 can be sucked one by one into each suction hole 20a.

In the above configuration, the ball mounting head 12
A description will be given of the operation of the arrangement of the conductive balls B from when they start sucking the balls to when the conductive balls B are mounted on the mounting object. The conductive balls B in the ball tray 14 in the ball supply device 13 are jumping by the vibrator 15. As shown by the dotted line in FIG.
By lowering to a predetermined height position, the jumping conductive ball B is sucked.

When the ball mounting head 12 moves to the ball mounting stage 10 along the guide rail 11 after adsorbing the conductive balls B, in order to efficiently remove a line or an area of a misaligned ball, which will be described later. The primary removal of surplus balls may be performed. As the primary removal of the surplus balls, the surplus balls on the entire arrangement surface are removed to such an extent that the balls passing over the ball removing mechanism and properly adsorbed balls are not removed. Thereafter, the array inspection camera 17 moves in the X direction to inspect the ball suction state on the entire array surface of the array plate 20. If the inspection result by the array inspection camera 17 is good, the camera moves to the ball mounting stage 10. In addition, if an alignment error is found during this inspection, the line or area of the alignment error ball is removed as described later.

Next, the positioning of the ball mounting head 12 with respect to the wafer W waiting on the ball mounting stage 10 is performed. Then, by lowering the ball mounting head 12, the conductive balls B adsorbed on the array plate 20 are mounted on the electrode portions of the wafer W coated with the flux. The ball mounting head 12 is configured so that the contact load when contacting the wafer W can be controlled in accordance with the type of the conductive balls. Thus, the conductive balls B can be brought into contact with the wafer W with an optimum load, and the conductive balls B can always be properly and smoothly mounted.

After the balls are mounted on the wafer W, the camera 17 for array inspection checks whether or not there are balls remaining on the array plate 20 after the balls are mounted. If there is a remaining ball, the remaining ball can be removed by suction by the ball removing mechanism 16.

If, during the ball arrangement inspection by the arrangement inspection camera 17, an arrangement failure that cannot be removed by the primary removal performed immediately after the ball suction is found, the nozzle 18 of the ball removal mechanism 16 causes the ball arrangement failure to occur. The conductive ball B in the region including the site is suctioned and removed in a line shape or an area shape. For example, as shown in FIG. 3, it is assumed that there is a ball arrangement defect with respect to the semiconductor chip C (hatched portion) located on the (2, 3) coordinate in the XY coordinate on the wafer W. That is, as shown in FIG.
It is assumed that it is detected that the excess ball B 'is being sucked into the suction hole 20a corresponding to any of the electrodes included in the above.

In this case, the ball mounting head 12 uses the position data at the time of detection of the misalignment to detect the area of the line L (the hatched portion) including the semiconductor chip C located at the (2, 3) coordinates described above. The nozzle 18 moves to the corresponding removal position and strongly sucks the conductive ball B in the area including the suction hole 20a for sucking the surplus ball B 'in a line shape. FIG. 4 schematically shows the state at this time. However, by suctioning as in this example, the conductive ball B in the area including the ball B normally sucked and the surplus ball B ′ is drawn.
Are removed in a line.

After the removal of the error balls, the conductive balls B are re-adsorbed to the area of the arrangement plate 20 where the lines are removed, and it is confirmed that the conductive balls B are properly arranged.
In the same manner as described above, the ball mounting head 12 is aligned with the wafer W waiting on the ball mounting stage 10, and by lowering the ball mounting head 12, the conductive attracted to the array plate 20 is lowered. The conductive ball B is mounted on the electrode portion of the wafer W.

Next, an embodiment in the case where surplus balls are removed in the form of an area will be described. Also in this example, it is assumed that there is a ball arrangement defect with respect to the semiconductor chip C (hatched portion) located on the (2, 3) coordinates in the XY coordinates on the wafer W as shown in FIG. That is, as shown in FIG. 6, it is assumed that it is detected that the excess ball B 'is sucked in the suction hole 20a corresponding to one of the electrodes included in the semiconductor chip C.

In this embodiment, as shown in FIG. 6, a sliding shutter 21 is arranged above the nozzle 18. The shutter 21 is a flat member, and is configured to be reciprocally movable (for example, in the X direction) as shown by an arrow A by a drive / support mechanism (not shown). The amount of movement of the shutter 21, and thus the position thereof, is precisely controlled via a drive / support mechanism.

When the shutter 21 slides above the nozzle 18, the shutter 21 moves in close contact with the opening of the nozzle 18, so that air does not flow in (or out) from the gap between the two. Further, the shutter 21 has an opening 2 having a size corresponding to, for example, approximately one semiconductor chip C.
1a has been established. The size of the opening 21a is
This can be changed as needed, and the error ball removal area can be changed in a wide or narrow manner in accordance with the change.

In this embodiment, the ball mounting head 12
And the shutter opening position is moved to the removal position corresponding to the area (shaded area) of the semiconductor chip C located at the above (2, 3) coordinates by using the position data at the time of detecting the position of the defective array. The conductive ball B in the area including the suction hole 20a for sucking B 'is strongly sucked in the form of an area by the nozzle 18 through the shutter 21. By suctioning as in this example, the conductive ball B in the area including the ball B that has been properly sucked and the surplus ball B ′ is removed in the form of an area.

As described above, the area from which the error ball is removed can be changed in a wide or narrow manner. For example, by further reducing the area of the opening 21a, the area of the removed portion can be subdivided. This reduces the range in which the conductive balls B that are properly adsorbed are removed, and enables efficient removal without waste.

FIG. 7 shows an example in which the rotary shutter 22 is arranged around the nozzle 18. The shutter 22 is a cylindrical member, and is configured to be rotatable as indicated by an arrow θ by a drive / support mechanism (not shown). The rotation angle θ of the shutter 22 is precisely controlled via a drive / support mechanism.

When the shutter 22 rotates around the nozzle 18, the shutter 22 rotates in close contact with the opening of the nozzle 18, so that air does not flow in (or out) through a gap between the two. The shutter 22 has a plurality of openings 22a having a size corresponding to, for example, approximately one semiconductor chip C. These openings 22a are
For example, the rotation angles are set so as to correspond to the X coordinates on the wafer W with respect to the rotation angles θ _{0 to} θ _{n at the same} pitch.

In this embodiment, the opening 22 corresponding to the area of the semiconductor chip C located at the above (2, 3) coordinates
The shutter 22 is rotationally driven so that a is set on the nozzle 18. Then, the conductive ball B in the area including the suction hole 20a for sucking the surplus ball B 'is strongly sucked in the area by the nozzle 18 through the shutter 22. Also in this example, the conductive ball B in the area including the ball B and the surplus ball B 'that have been properly attracted is removed in an area.

In each of the above embodiments, the example in which the misaligned balls in the ball mounting head 12 are removed by suction of the nozzles 18 has been described. However, the balls can be similarly removed by blowing gas from the nozzles 18. . Further, the shape of the nozzle is not limited to that shown in FIG. 4, FIG. 6, or FIG. 7, and the nozzle itself may be as small as the shutter opening, and may be configured to move to a defective array. Is also good.

[0039]

As described above, according to the present invention, in this type of ball arrangement apparatus or method, when a large number of balls are collectively arranged as in the case of forming ball bumps on a wafer, suction failure occurs. At this time, by removing the error balls in a line shape or an area shape, the defect occurrence rate at the time of rearrangement can be suppressed remarkably low. Further, the error balls firmly adhered to the array plate can be accurately removed by suction or gas flow. Furthermore, when conducting an array inspection of suction balls, not only the presence or absence of a defect but also the coordinates of the error position can be recognized, so that the defective portion can be accurately removed, thereby greatly improving the yield and productivity. It has the advantage that it can be done.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a device of the present invention.

FIG. 2 is a diagram showing a configuration around a ball mounting head in the apparatus of the present invention.

FIG. 3 is a plan view showing an example of a wafer on which conductive balls are mounted according to the embodiment of the present invention.

FIG. 4 is a diagram illustrating a state where a ball is sucked in a line shape by a nozzle according to the embodiment of the present invention.

FIG. 5 is a plan view showing an example of a wafer on which conductive balls are mounted according to another embodiment of the present invention.

FIG. 6 is a diagram showing a state when a ball is sucked in an area by a nozzle according to another embodiment of the present invention.

FIG. 7 is a diagram illustrating a configuration example in which a ball is suctioned in an area shape by a nozzle according to another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 10 Ball mounting stage 11 Guide rail 12 Ball mounting head 13 Ball supply device 14 Ball storage container (ball tray) 15 Vibrator 16 Alignment defective ball removing mechanism 17 Camera for array inspection 18 Nozzle 19 Suction mechanism 20 Array plate 20a Suction hole 21 Sliding shutter 22 Rotating shutter

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Eiji Hashino 20-1 Shintomi, Futtsu-shi Nippon Steel Corporation Technology Development Division (72) Inventor Kazuo Niizuma 58-58 Soyodamotocho, Kanazawa-shi, Ishikawa Shibuya F-term (reference) 5E319 AB10 BB04 CD26 GG15

Claims (7)

[Claims] 1. A ball array mounting method in which conductive balls are suction-arranged on an array plate, and then the conductive balls are collectively mounted on electrodes of a mounting object on which the balls are to be mounted. When arranging balls on a board, the method includes a step of detecting a defective ball arrangement portion and removing the conductive balls in a region including the defective arrangement portion in a line shape or an area shape. Method. 2. The conductive ball array mounting method according to claim 1, wherein the conductive balls are removed in a line or area by a gas flow. 3. The method as claimed in claim 2, wherein the gas flow is an air flow or an inert gas flow. 4. The conductive ball array mounting method according to claim 1, wherein the conductive balls are removed in a line shape or an area shape by suction. 5. A ball array mounting device, wherein a conductive ball is suction-arranged on an array plate, and then the conductive ball is collectively mounted on an electrode of a mounting object on which the ball is to be mounted. A conductive ball arrangement mounting device, comprising: a ball removing mechanism for removing conductive balls in a region including a defective ball arrangement portion in a line or area shape when arranging balls on a board. 6. The conductive ball array mounting apparatus according to claim 5, wherein said ball removing mechanism includes gas ejection means for removing said conductive balls by a gas flow. 7. The conductive ball array mounting device according to claim 5, wherein the ball removing mechanism includes a suction unit that removes the conductive ball by suction.