JPH07153766A - Method and apparatus for jointing ball-shaped bump - Google Patents

Abstract

PURPOSE:To join a ball-shaped bump to an electrode pad easily and surely, by using an array board, on which fine metallic balls are arrayed corresponding to the electrode pads, picking up a group of metallic balls necessary at least for a semiconductor chip from the array board, and carrying the metallic balls to a jointing stage. CONSTITUTION:An array board 12, on which a plurality of balls for chips are arrayed, is mounted on a substrate suction stage 11. Each ball is sucked and put in array through a suction through hole 13. After the substrate suction stage 11 is carried to a pick-up stage 3, the array board 12 is turned over and put on the pick-up stage 3. The array board 12 is carried by a pick-up nozzle 4 in X-Y directions so that the group of balls (B) necessary for a semiconductor chip is carried to a suction position. Then, the array board 12 is aligned and the arrayed balls (B) for the semiconductor chip are sucked by the pick-up nozzle 4. Then, the pick-up nozzle 4 sucking the balls for the semiconductor chip is carried to a jointing stage 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ball-shaped bump bonding method and bonding apparatus for bonding ball-shaped bumps to inner leads of a film carrier or electrode pads of a semiconductor chip.

[0002]

2. Description of the Related Art Conventionally, there are a wafer bump and a stud bump as bumps formed on electrode pads on a semiconductor chip.

A wafer bump is used to form a bump in a semiconductor device at the wafer stage, and since a complicated process must be performed many times as a wafer process, the yield is low, and the cost is high for a small quantity and a wide variety of products. Becomes

The stud bumps are formed by ball-bonding the electrode pads of the semiconductor chip one at a time during the primary bonding of the wires and cutting the neck portion of the wires after the bonding. The rest of the wire remains convex and uneven at the cut portion. Therefore, the bonding reliability using this bump is considerably low. Also, it takes time to bump one pin at a time.

Further, as a method of bonding the bumps to the inner leads of the film carrier, there is a transfer bump in which the bumps plated and grown on the substrate are bonded to the inner leads. The bump width becomes larger than the required bump height, which is not suitable for narrow pitch bonding of 100 μm or less.

[0006]

As a measure against the above-mentioned problems in conventional bump bonding, it has been proposed to use a fine metal ball and transfer this ball to the inner lead. Since the balls are arranged one by one on the joining stage when arranging the balls by one, there is a problem that it takes a very long time.

Therefore, the present invention provides a bonding method and a bonding device for a ball-shaped bump, which can easily and reliably bond a ball-shaped bump to an inner lead of a film carrier or an electrode pad on a semiconductor chip. To aim.

[0008]

In order to achieve the above object, in the ball-shaped bump bonding method according to the present invention, fine metal balls are arranged at the same positions as the electrode pads of the semiconductor chip to be connected. At least one metal ball group of a semiconductor chip is collectively picked up from an array substrate, conveyed to a joining stage, and joined to a joined portion.

Also, the ball-shaped bump bonding apparatus according to the present invention is a ball for arranging fine metal balls in the array holes of the array substrate in which the array holes are provided at the same positions as the electrode pads of the semiconductor chip to be connected. Arrangement means, board conveying means for conveying the arrangement substrate on which the fine metal balls are arranged to the pickup stage, and a group of metal balls for at least one semiconductor chip collectively from the arrangement substrate conveyed to the pickup stage. Pickup means having a pickup nozzle for picking up, nozzle transfer means for transferring the pickup nozzle that collectively picks up the metal ball group to the joining stage, and the metal carried by the pickup nozzle to the joining stage A joining means for joining the ball group to the joined portion, It is those with a.

[0010]

According to the present invention constructed as described above, since the fine metal balls are used as the bumps, the bump width (diameter) can be made smaller than that of the bumps formed by the substrate plating, and the narrow pitch can be achieved. Joining becomes easy. And
Since at least one metal ball group of the semiconductor chips is picked up from the array substrate at a time, the metal balls can be surely bonded to the inner leads of the film carrier or the electrode pads on the semiconductor chip at one time. Significantly reduced time and cost.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

First, as shown in FIG. 1, this apparatus has a ball arranging mechanism 1 and a substrate transfer mechanism 2 as main components.
, Pickup stage 3, pickup nozzle 4
And a nozzle transport mechanism 5 and a joining stage 6. This device can be constructed by adding a function of arranging and bonding the fine metal balls to a device having a bonding mechanism such as an inner lead bonder.

Next, in the ball arranging mechanism 1, FIG.
As shown in FIG.
Then, the array substrate 12 capable of arranging balls of a plurality of chips shown in FIG. 3 is mounted. Then, as shown in FIG. 4, the balls B are sucked and arranged one by one in the through suction holes 13 formed in the array substrate 12. The balls B are arranged in the recess 14 one by one. Further, the suction holes 15 of the substrate suction stage 11 have a larger diameter than the suction holes 13 of the array substrate 12, so that the array substrate 12 is held by the substrate suction stage 11.

As shown in FIG. 5, the balls B are arrayed in a lump by lowering and raising the array substrate 12 with respect to the ball stock tray 16 in order to shorten the time. Note that, in FIG. 5, the substrate suction stage 11 that holds the array substrate 12 is not shown. Next, the excess balls B ′ other than the vacuum-adsorbed balls B are mechanically removed by the plate member 17 or the like and collected. At this time, since the balls B normally arranged in the suction holes 13 are in the recesses 14, the balls B are not removed.

Next, the substrate transfer mechanism 2 shown in FIG. 1 transfers the substrate suction stage 11 (not shown) that holds the array substrate 12 to the pickup stage 3. At the time of this conveyance, the ball B is prevented from being dropped due to vibration or the like. The array substrate 12 that has already been picked up is returned to the ball array mechanism 1. The substrate suction stage 11
May be provided in two sets.

Next, as shown in FIG. 6, the array substrate 12 is inverted and placed on the pickup stage 3. At this time, the amount of displacement of the array substrate 12 with respect to the pickup stage 3 is set within a range in which position correction during pickup can be performed. Then, the array substrate 12 is moved XY by the pick-up nozzle 4 to a position (pick-up position) where the balls B on which one semiconductor chip is arranged are attracted. Then, the ball array recognition means 7 recognizes the presence / absence of the balls B adsorbed on the array substrate 12 and the presence / absence of the surplus balls B ′ before picking up on a chip basis. At this time, if a defect is recognized even for one ball, the process moves to the next one chip.

Next, the array substrate 12 is aligned by XYθ, and the ball B for one arrayed semiconductor chip is adsorbed by the pickup nozzle 4. As shown in FIG. 7, a substrate 42 in which suction holes 41 are arranged is mounted on the surface of the pickup nozzle 4, and suction is performed by the suction holes 43. At the time of this pickup, the substrate suction stage 1 shown in FIG.
By using the adjusting valve 19 of the vacuum pump 18 on the first side and the adjusting valve 45 of the suction pump 44 on the pickup nozzle 4 side shown in FIG. 7, the vacuum suction between the array substrate 12 and the pickup nozzle 4 can be switched. Good.

Next, the pick-up nozzle 4 which has sucked the ball is carried to the joining stage 6 by the nozzle carrying mechanism 5 shown in FIG. During this transportation, the balls should not drop out due to vibration or the like.

As shown in FIG. 8, the pickup nozzle 4
When conveying the wafer to the joining stage 6, the ball recognition means 8
Check for the presence of ball B by. Further, as shown in FIG. 9, a substrate 62 in which suction holes 61 are arranged is mounted on the surface of the bonding stage 6, and suction is performed by the suction holes 63. The bonding stage 6 has the same area as that of the semiconductor chip.

Next, the suction holes 61 of the joining stage 6 and the conveyed balls B of the nozzles 4 are aligned (XY stage of the pickup nozzle 4 is corrected by XYθ). Then, the pickup nozzle 4 is lowered and the ball B is replaced in the suction hole 61 on the joining stage 6. This is performed by switching vacuum suction between the adjustment valve 45 of the suction pump 44 on the pickup nozzle 4 side shown in FIG. 7 and the adjustment valve 65 of the suction pump 64 on the joining stage 6 side shown in FIG. As a result, the ball B is attracted to the joining stage 6.

Then, all the balls B attracted and arranged on the joining stage 6 are recognized by the ball recognition means 9.
It should be noted that this recognition may be omitted, and the recognition function of the inner lead bonder may be used. When a defect such as a missing ball is recognized, the ball B is mechanically removed and re-adsorbed.

Finally, after aligning the balls B arranged on the joining stage 6 with the inner leads 70 of the film carrier, the balls B are joined (transferred) to the inner leads 70. This joining can be performed using the function of the inner lead bonder device main body.

Next, when the balls are bonded to the electrode pads of the semiconductor chip, the semiconductor chip 80 is placed on the bonding stage 6 as shown in FIG. Then, the pickup nozzle 4 is lowered to move the ball B to the semiconductor chip 8
Then, the heating tool 81 presses the pickup nozzle 4 to bond the ball B to the electrode pad. In addition, at the time of this joining, the nozzle with heater 82
May be used.

Next, another embodiment of the present invention will be described. In this embodiment, in particular, the suction system is composed of two systems so as to exhibit an appropriate suction function.

By the way, as described above, the array substrate 12
Since the suction holes 13 of 1 are required to be arrayed with high precision, they are used as dedicated substrates, and the suction function for the array substrate 12 is provided by the substrate suction stage 11 and is configured by two members. In this case, the suction on the array substrate 12 is performed by using the suction force on the balls B. Therefore, if the suction force is set based on the suction of the balls B, the suction force on the array substrate 12 is set. Is weakened, the array substrate 12 may be displaced.
On the other hand, if the suction force is set to be strong, there is a risk that leakage from the outside air will occur via the suction holes 13 and the extra balls B will be sucked and attached.

11 and 12 show examples of the arrangement of the array substrate 112 and the substrate suction stage 111 in this embodiment, respectively. The array substrate 112 is capable of ball array for four semiconductor chips. The substrate suction stage 111 is a suction groove 1 formed in a lattice shape (for example, a “T” shape) corresponding to four semiconductor chips.
20, the suction groove 120 is connected to a vacuum source such as a vacuum pump via a suction pipe 121 as shown in FIG. In addition, the substrate suction stage 111 has 4
One suction hole 115 is formed, and each suction hole 115 is formed.
Is connected to a vacuum source such as a vacuum pump via a suction pipe 122 (see FIG. 13B).

Then, the array substrate 112 is superposed so as to be aligned with the substrate suction stage 111 as shown in FIG. 14, and is sucked and fixed through the suction holes 115. The recess 114 is formed in each suction hole 113 of the array substrate 112.
The balls B are attracted and arranged inside. In this way, the suction system for fixing the array substrate 112 and the suction system for sucking the balls B are composed of two separate systems. in this case,
Particularly in the suction system for sucking the ball B, FIG.
As shown in (A), a suction pipe 121 is provided with a regulator 123 for controlling a vacuum pressure, so that the strength of the suction force when sucking the ball B in the suction holes 113 of the array substrate 112 can be adjusted. Has become.

Here, FIGS. 15 and 16 show examples of the structure of the substrate suction stage 111 'and the array substrate 112' corresponding to one semiconductor chip. As shown in FIG. 15, the substrate suction stage 111 'has a suction groove 120' along its periphery, and this suction groove 120 'is shown in FIG.
As shown in FIG. 6 (B), it is connected to a vacuum source such as a vacuum pump via a suction pipe 121 '. A suction hole 115 'is formed in the center of the substrate suction stage 111', and this suction hole 115 'is connected to a vacuum source such as a vacuum pump via a suction pipe 122' (FIG. 16). (A)
reference). Even in the case of the array substrate 112 'in which the balls B for one semiconductor chip can be arrayed in this way, the suction system is composed of two systems.

Also in the case of the array substrate 112 'corresponding to one semiconductor chip, the suction tube 121' is provided with the regulator 12 for controlling the vacuum pressure as shown in FIG. 16 (A).
3'is attached, but the array substrate 112 'in the case of this example
Then, there are 328 suction holes with a diameter of 30 μm (82 per side).
In the case where the balls B are formed, the vacuum pressure for adsorbing the balls B is preferably about 50 to 60 mmHg.

Next, the operation of this embodiment in a specific bonding process when the substrate suction stage 111 and the array substrate 112, which are composed of the above-described two suction systems, are used will be described.

In the ball arranging mechanism 1, as shown in FIG. 17, a substrate suction stage 111 having a suction function,
An array substrate 1 capable of ball array of four semiconductor chips
12 is mounted (see FIG. 14). Further, the ball stock tray 16 is vibrated. That is, the ball B is put into the ball stock tray 16 and vibrated by the vibration generator 124 such as a parts feeder. As a result, the ball B floats effectively. The vibration frequency at this time is variable from 0 to 1 kHz according to the size of the ball B and the like, and is preferably 300 to 400 Hz. Further, the ball stock tray 16 can be attached to and detached from the vibration generator 124.

Then, the array substrate 112 is lowered to the vicinity of the ball stock tray 16 as indicated by an arrow in FIG. 17, and the balls B are vacuum-sucked in the suction holes 113 of the array substrate 112 while swinging vertically. This adsorption hole 1
The suction force for sucking the ball B in 13 is optimally set by the regulator 123 (see FIG. 13), and it is possible to prevent the excessive ball B from adhering to each suction hole 113.

When the array substrate 112 is raised as shown by the arrow in FIG. 17, and then the ultrasonic transducer 126 is operated by the controller (ultrasonic oscillator) 125,
Ultrasonic vibration is applied to the array substrate 112. As a result, the extra balls B ′ attached to the array substrate 112 are
All are instantaneously separated from the array substrate 112 and fall. The timing of operating the ultrasonic oscillator 126 may be set so that the array substrate 112 is ultrasonically vibrated at the same time as the ball B is attracted.

Next, the substrate transfer mechanism 2 shown in FIG. 1 transfers the substrate suction stage 111 (not shown) that holds the array substrate 112 to the pickup stage 3. At the time of this conveyance, the ball B is prevented from being dropped due to vibration or the like. Array board 1 that has already been picked up
12 returns to the ball arranging mechanism 1. Two sets of the substrate suction stage 111 may be provided. Then, the ball array recognition means 7 recognizes the presence / absence of the balls B adsorbed on the array substrate 112 and the presence / absence of the surplus balls B ′ before picking up, on a chip-by-chip basis. At this time, if a defect is recognized even for one ball, the process moves to the next one chip.

As shown in FIG. 18, the array substrate 112 is inverted and placed on the pickup stage 3. Then, the array substrate 112 is moved XY by the pickup nozzle 104 to a position (pickup position) where the balls B on which one semiconductor chip is arrayed are attracted. The array substrate 112 is aligned by XYθ, and the ball B for one arrayed semiconductor chip is adsorbed by the pickup nozzle 104.

Here, in the pick-up nozzle 104, as shown in FIG. 19, a substrate 142 having suction holes 141 arranged on the surface is mounted, and the suction holes 143 suck the balls B through the suction holes 141. Has become.
The suction hole 143 is connected to the vacuum pump 144 via the regulator 145. In addition to the suction system for sucking the balls B, a suction system (not shown) for fixing the substrate 142 is provided, that is, the pickup nozzle 104 serves as a suction system for fixing the substrate 142. It has two suction systems for sucking the ball B. The pickup nozzle 10
4 may be selectively used as needed. That is, instead of the pickup nozzle 104, the pickup nozzle 4 described above can be used.

Next, the pick-up nozzle 104 which has attracted the ball B is carried to the joining stage 6 by the nozzle carrying mechanism 5 of FIG. 1 (FIG. 20). During this transportation, the balls should not drop out due to vibration or the like. In particular, when the ball B is bonded to the electrode pad of the semiconductor chip, the semiconductor chip 80 is placed on the bonding stage 6 as shown in FIG. Then, after the pickup nozzle 104 is aligned with the joining stage 6, it is lowered to bring the ball B into contact with the electrode pad of the semiconductor chip 80 to press the pickup nozzle 104,
The ball B is bonded to the electrode pad. A nozzle with a heater may be used during this joining.

By the way, in the above-mentioned embodiment, for example, when picking up the ball B from the array substrate 12 which attracts the ball B, the pickup nozzle 104 is used instead of the pickup nozzle 4 shown in FIG. be able to. Even in this case, by using the pickup nozzle 104 having two suction systems, it is possible to prevent extra balls B ′ from adhering when the balls B are picked up from the array substrate 12.

The embodiments of the present invention have been described above.
The present invention is not limited to the above embodiments, and various effective modifications and applications are possible based on the technical idea of the present invention. In particular, the case where the ball B is bonded to the inner lead 70 of the film carrier or the electrode pad of the semiconductor chip 80 has been described, but the invention can be effectively applied to the case of bonding to the electrode pad of the printed circuit board.
Further, although the example of the ball B forming the bump has been described, the present invention can be effectively applied to the case of performing this type of bonding using a microsphere made of a conductive rubber material.

[0040]

As described above, according to the present invention,
Since the minute metal balls are used as the bumps, the bump width (diameter) can be made smaller than that of the bumps formed by substrate plating, and the narrow pitch bonding becomes easy. Since the metal balls for one semiconductor chip are collectively picked up from the array substrate, the metal balls can be surely bonded to the inner leads of the film carrier or the electrode pads on the semiconductor chip all at once. Significantly reduced time and cost. As a result, the film carrier with ball bumps can be mass-produced, and the bumps can be easily attached to the electrode pads of the semiconductor chip at low cost.

Further, when the metal balls are attracted to the array substrate, the suction system is constituted by two systems so that an appropriate suction function is exerted, and the array substrate is subjected to ultrasonic vibration to provide the array. It has advantages such as being able to completely prevent extra metal from adhering to the substrate.

[Brief description of drawings]

FIG. 1 is a schematic plan view showing the configuration of the entire apparatus in an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a substrate suction stage and an array substrate in an embodiment of the present invention.

FIG. 3 is a plan view showing an array substrate in an example of the present invention.

FIG. 4 is an enlarged cross-sectional view showing a main part of a substrate suction stage and an array substrate in an embodiment of the present invention.

FIG. 5 is a schematic view showing a ball arranging operation by the ball arranging mechanism in the embodiment of the present invention.

FIG. 6 is a schematic diagram showing a collective pickup operation of balls by a pickup nozzle in the embodiment of the present invention.

FIG. 7 is a cross-sectional view showing a pickup nozzle according to an embodiment of the present invention.

FIG. 8 is a schematic diagram showing ball bonding to leads of a film carrier in an example of the present invention.

FIG. 9 is a cross-sectional view showing a joining stage in an example of the present invention.

FIG. 10 is a schematic diagram showing ball bonding to an electrode pad of a semiconductor chip in an example of the present invention.

FIG. 11 is a plan view showing a configuration example of an array substrate capable of attracting balls for a plurality of semiconductor chips according to another embodiment of the present invention.

FIG. 12 is a plan view showing a configuration example of a substrate suction stage corresponding to the array substrate in another embodiment of the present invention.

13A is a sectional view taken along line KK of FIG.
FIG. 13B is a sectional view taken along the line LL in FIG.

FIG. 14 is a cross-sectional view of an array substrate capable of attracting balls for the plurality of semiconductor chips and a substrate suction stage thereof.

FIG. 15 is a semiconductor chip 1 according to another embodiment of the present invention.
It is a top view showing an example of composition of an array substrate which can adsorb the balls for an individual piece.

16A is a sectional view taken along line K′-K ′ of FIG. 15, and FIG. 16B is a sectional view taken along line L′-L ′ of FIG. 15.

FIG. 17 is a schematic view showing ball arranging operation by the ball arranging mechanism in another embodiment of the present invention.

FIG. 18 is a schematic view showing a step of transferring an array substrate to a pickup stage according to another embodiment of the present invention.

FIG. 19 is a sectional view showing a pickup nozzle according to another embodiment of the present invention.

FIG. 20 is a schematic view showing ball bonding to an electrode pad of a semiconductor chip according to another embodiment of the present invention.

[Explanation of symbols]

 1 Ball Arrangement Mechanism 11,111 Substrate Adsorption Stage 12,112 Arranged Substrate 13,113 Through Adsorption Hole 14,114 Recess 16 Ball Stock Dish 2 Substrate Transfer Mechanism 3 Pickup Stage 4,104 Pickup Nozzle 41,141 Adsorption Hole 5 Nozzle Transfer Mechanism 6 Bonding Stage 61 Adsorption Holes 7 Ball Array Recognition Means 8 Ball Recognition Means 9 Ball Recognition Means 70 Film Carrier Leads 80 Semiconductor Chips 81 Heating Tools 82 Heater Nozzles B Balls

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Hiba 1618 Ida, Nakahara-ku, Kawasaki City Nippon Steel Corp. Advanced Technology Research Laboratories

Claims (11)

[Claims] 1. A metal ball group for at least one semiconductor chip is collectively picked up from an array substrate in which fine metal balls are arranged so as to be at the same position as an electrode pad of a semiconductor chip to be connected, and this is picked up. A method of joining ball-shaped bumps, which is characterized in that the bumps are conveyed to a joining stage and joined to a joined portion. 2. The ball-shaped bump according to claim 1, wherein the group of metal balls picked up at one time is arranged on the joining stage, and the group of metal balls is joined to an inner lead of a film carrier. How to join. 3. The method of bonding ball-shaped bumps according to claim 1, wherein the group of metal balls picked up at a time is bonded to the electrode pads of the semiconductor chip mounted on the bonding stage. 4. A ball arranging means for arranging fine metal balls in the arrangement hole of an arrangement substrate having an arrangement hole provided at the same position as an electrode pad of a semiconductor chip to be connected, and the fine metal balls are arranged. And a pickup means having a pickup nozzle for collectively picking up at least one metal ball group of semiconductor chips from the array substrate transported to the pickup stage. Nozzle transporting means for transporting the pickup nozzle that collectively picks up the metal ball group to the joining stage, and joining means for joining the metal ball group transported by the pickup nozzle to the joining stage to a joined portion. And a ball-shaped bump of Coupling devices. 5. The ball for a plurality of semiconductor chips can be arranged on the array substrate.
The ball-shaped bump bonding apparatus described. 6. The ball arrangement in the array substrate and / or the pick-up means is performed by vacuum suction, and a first vacuum suction means for fixing the array substrate and a first vacuum suction means for sucking the metal balls. 5. The ball-shaped bump bonding apparatus according to claim 4, further comprising: 2 vacuum suction means. 7. The metal ball is stored in a predetermined container in advance, and the metal ball is made to float by applying a slight vibration to the container. Bonding device for ball-shaped bumps. 8. The ball shape according to claim 4, further comprising a ball recognition means and an alignment means for confirming a ball arrangement state before being picked up by the pickup nozzle and enabling alignment with the pickup nozzle. Bump bonding device. 9. The ball-shaped bump bonding apparatus according to claim 4, wherein the ball arranging means and the pickup means are arranged independently of each other. 10. The group of metal balls collectively picked up by the pickup nozzle is arranged on the joining stage, and the group of metal balls is joined to the inner lead of the film carrier by the joining means. Item 4. A ball-shaped bump bonding apparatus according to Item 4. 11. The ball-shaped bump according to claim 4, wherein the group of metal balls collectively picked up by the pickup nozzle is bonded to an electrode pad of a semiconductor chip mounted on the bonding stage. Joining device.