JP2000040709A - Apparatus and method for transferring conductive balls - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a transfer device and a transfer method of a conductive ball, which can shorten a tact time and prevent a trouble caused by adhesion of a flux. SOLUTION: A conductive ball 3 of a ball supply unit 1 is vacuum-sucked by a first suction head 4 and picked up.
The conductive balls 3 held by inverting the first suction head 4 are transferred to the second suction head 9. Then the second
After the flux is transferred to the conductive ball 3 by moving the suction head 9 up and down with respect to the flux transfer unit 11, the second suction head 9 is moved to move the conductive ball 3 to the work 16.
Transfer to As a result, the tact time can be shortened, and the pickup head and the flux transfer suction head are separated from each other, thereby preventing the flux from adhering to the first suction head 4 and allowing the ball supply unit 1 Flux contamination of the conductive ball 3 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive ball transfer apparatus and method for transferring conductive balls to a work such as a substrate or an electronic component.

[0002]

2. Description of the Related Art As a method of forming a metal bump on an electrode of a substrate or an electronic component, there is known a method of transferring a conductive ball such as a solder ball onto an electrode and soldering the electrode. For transferring the conductive balls, a method of vacuum-sucking the conductive balls by a suction head is widely used. This method
The conductive balls are sucked into a large number of suction holes provided on the lower surface of the suction head, the suction head is moved onto the work, and the vacuum suction is released to transfer the conductive balls to the work. Then, in order to improve the solder jointability between the conductive balls and the electrodes of the work, a flux is applied to the conductive balls before transfer to the work. This application is performed by lowering the suction head holding the conductive balls on the coating film on which the flux is printed to a predetermined thickness, and transferring the conductive balls by bringing the lower ends of the conductive balls into contact with the film-like flux.

[0003]

As described above, the transfer of the conductive ball requires the steps of picking up the conductive ball by vacuum suction, transferring the flux to the conductive ball, and transferring to the work. However, the conventional method of transferring conductive balls has the following problems. First, each step of the above-described pickup by vacuum suction, flux transfer to a conductive ball, and transfer to a work requires a predetermined time, and there is a limit to speeding up each of these steps. For this reason, it has been practically difficult to significantly reduce the tact time for transferring the conductive balls more than before.

[0004] Further, as the size of the conductive ball becomes smaller, flux tends to adhere to the lower surface of the suction head at the time of flux transfer, causing the following problems. First, when the suction head to which the flux has adhered sinks into the conductive ball layer in the ball supply unit, the flux attached to the suction head adheres to the conductive ball and becomes contaminated. The conductive balls contaminated by the flux adhere to each other due to the adhesive force of the flux, preventing normal suction into the suction holes of the suction head during pickup,
Extra conductive balls adhere to the lower surface of the suction head, which causes extra balls. And it is practically impossible to remove the conductive balls contaminated by the flux by removing them.There is no other way but to dispose of the conductive balls to which the flux is attached, and to reduce the yield of the conductive balls. It was an inviting factor.

As described above, according to the conventional method for transferring conductive balls, it is difficult to shorten the tact time, and the conductive balls are poorly adsorbed due to the adhesion of the flux to the suction head at the time of flux transfer. However, there is a problem that the yield is lowered.

Therefore, the present invention can reduce the tact time and, when performing the application of an adhesive bonding material such as a flux at the same time, can prevent problems caused by the adhesion of the adhesive bonding material. It is an object of the present invention to provide a conductive ball transfer device and a transfer method that can be used.

[0007]

According to a first aspect of the present invention, there is provided an apparatus for transferring a conductive ball, comprising: a ball supply unit for supplying the conductive ball; and a plurality of suction holes provided on a lower surface of the ball supply unit. A first suction head for picking up conductive balls, a second suction head provided with a plurality of suction holes on a lower surface for receiving the conductive balls from the first suction head, and moving the second suction head. Moving means for raising and lowering the second suction head relative to the work so as to mount the conductive balls held by the second suction head on the work.

According to a second aspect of the present invention, there is provided an apparatus for transferring a conductive ball, comprising:
An application unit is provided for applying an adhesive bonding material to the conductive balls held by the second suction head.

According to a third aspect of the present invention, there is provided an apparatus for transferring a conductive ball, comprising the steps of:
The first suction head and the second suction head have the same suction hole arrangement at least in part.

According to a fourth aspect of the present invention, there is provided an apparatus for transferring a conductive ball, comprising the steps of:
The taper angle of the ball introduction portion of the suction hole provided in the first suction head is smaller than the taper angle of the ball introduction portion of the suction hole provided in the second suction head.

According to a fifth aspect of the present invention, there is provided an apparatus for transferring a conductive ball, comprising:
The depth of the ball introduction part of the suction hole provided in the first suction head is deeper than the depth of the ball introduction part of the suction hole provided in the second suction head.

A conductive ball transfer device according to claim 6 is the conductive ball transfer device according to claim 1,
The Young's modulus of the material of the lower surface of the first suction head is larger than the Young's modulus of the material of the lower surface of the second suction head.

According to a seventh aspect of the present invention, there is provided a method for transferring a conductive ball, wherein the conductive ball stored in the ball supply unit is vacuum-sucked by a first suction head having a plurality of suction holes formed on a lower surface thereof and picked up. And transferring the conductive balls held by the first suction head to a second suction head provided with a plurality of suction holes on the lower surface, and moving the second suction head onto the work. Mounting the conductive ball held by the second suction head on the work while moving up and down relatively to the work.

The method for transferring conductive balls according to claim 8 is the method for transferring conductive balls according to claim 7, wherein
A step of applying an adhesive bonding material to the conductive balls held by the second suction head.

According to the invention described in each claim, a first suction head for picking up the conductive balls from the ball supply unit by vacuum suction, and a second suction head for mounting the conductive balls on the work. By providing two dedicated suction heads, it is possible to reduce pick-up errors and mounting errors, and to shorten the tact time. In the case where the adhesive bonding material is also applied, the suction head for pick-up and the transfer of the adhesive bonding material are separated from each other, so that the adhesive bonding material on the lower surface of the pickup suction head is used. Can be prevented from adhering.

[0016]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a front view of an apparatus for transferring conductive balls according to an embodiment of the present invention. FIGS. 2A and 2B are cross-sectional views of a suction head of the apparatus for transferring conductive balls.
(A), (b), and (c) are enlarged cross-sectional views of the suction head of the conductive ball transfer device, and FIGS. 4 (a), (b), and FIG.
(A), (b), (c), FIG. 6 (a), (b),
(C), (d) is process explanatory drawing of the transfer method of the same conductive ball.

First, an apparatus for transferring conductive balls will be described with reference to FIG. In FIG. 1, a ball supply unit 1 includes a container 2 in which a large number of conductive balls 3 are stored. Above the container 2, a first suction head 4
Are arranged. The first suction head 4 is moved up and down with respect to the conductive balls 3 of the container 2 by a lifting means (not shown).
By suctioning the inside of the first suction head 4 with the lower surface of the suction head 4 sinking into the surface layer of the conductive ball 3, the suction hole 4a (see FIG. 2) provided on the lower surface becomes conductive. The ball 3 is sucked by vacuum. Then, after the first suction head 4 is lifted from the container 2, the conductive ball 3 held in the suction hole 4 a is turned upside down by a reversing means (not shown) (the first suction head indicated by a chain line). 4).

Above the ball supply unit 1, an X-axis motor 6
An X-axis table 5 which is a moving means provided with is arranged in the horizontal direction. The X-axis table 5 is equipped with a Z-axis table 8 which is a lifting / lowering means provided with a Z-axis motor 7.
A second suction head 9 is mounted on the Z-axis table 8. By driving the X-axis table 5, the second suction head 9
Is moved above the first suction head 4 in the inverted state, and the Z-axis table 8 is driven to move the second suction head 9
Is lowered with respect to the first suction head 4,
The second suction head 9 receives the conductive ball 3.

On the side of the ball supply section 1, a flux application section 11 as a means for applying a flux as an adhesive bonding material is provided. The flux application unit 11 includes a container 12 on which the flux 13 is applied in a film shape. The flux 13 is transferred and applied to the lower end portion of the conductive ball 3 by raising and lowering the second suction head 9 holding the conductive ball 3 in the suction hole 9 a on the lower surface by vacuum suction and holding the second suction head 9 with respect to the container 12. .

A work positioning section 14 is provided on the side of the flux application section 11. The positioning unit 14 includes a moving table 15. By driving the moving table 15, the work 16 held by a holder of the moving table 15 is moved and positioned in a horizontal direction.

Next, the first suction head 4 and the second suction head 9 will be described with reference to FIG. FIG.
(A) shows a state in which the first suction head 4 is positioned opposite to the second suction head 9 with the suction surface turned upside down. The arrangement pitch of the suction holes 4a and the arrangement pitch of the suction holes 9a are both set to the same pitch p, and the arrangement of the suction holes of the first suction head 4 and the second suction head 9 is the same. . In this embodiment, the first suction head 4 and the second suction head 9 have the same shape and the same suction hole arrangement including the head outer dimensions, as shown in FIG. The present invention is not limited to this, and as long as at least a portion has the same suction hole arrangement, as shown in FIG. 2B, the suction surface size of the second suction head 9 is smaller than that of the first suction head 4 ′. 1 / integral of the suction surface size (1/2 in the example of FIG. 2B)
The combination may be such that

In such a case, the conductive ball sucked by the first suction head 4 'in one pick-up operation is transferred to the second suction head 9 in a plurality of times. Therefore, when targeting a conductive ball that requires a relatively long time for the pickup operation,
By employing such a combination of suction heads, the effect of shortening the tact time as a whole can be obtained.

Next, details of the shapes of the suction holes 4a and 9a will be described. FIGS. 3A and 3B show suction holes 4a and 9a provided on the lower surfaces of the first suction head 4 and the second suction head 9, respectively. The portions of the suction holes 4a and 9a that are opened on the lower surfaces of the first suction head 4 and the second suction head 9 are tapered ball introduction portions, and are used for holding conductive balls during vacuum suction. It has a suitable shape. Hereinafter, the shape of the ball introduction portion will be described in comparison with the two suction holes 4a and 9a.

As shown in FIGS. 3A and 3B, the ball introduction portion of the first suction head 4 used only for picking up the conductive ball 3 is transferred to the work 16 of the flux transfer and the conductive ball 3. The taper angle θ1 of the ball introduction portion of the first suction head 4 is smaller than the taper angle θ2 of the ball introduction portion of the second suction head 9 as compared with the ball introduction portion of the second suction head 9 used for mounting the device. Is also set small. Further, the depth d1 of the ball introduction portion of the first suction head 4 is set to be deeper than the depth d2 of the ball introduction portion of the second suction head 9. Further, the material is selected so that the Young's modulus (longitudinal modulus) of the material of the first suction head 4 is higher than the Young's modulus of the material of the second suction head 9. In the present embodiment, The first suction head 4 is made of metal such as stainless steel or ceramic,
Is made of resin.

The difference between the shapes and materials of the ball introduction portions of the first suction head 4 and the second suction head 9 has the following significance. First, in order to stably vacuum-suction conductive balls randomly stored in a container, it is necessary to ensure that one conductive ball corresponds to one suction hole. This is because, if vacuum suction is performed in a state where the suction holes are not completely closed, a suction failure that simultaneously sucks a plurality of conductive balls around the suction holes is caused. That is, as the depth of the ball introduction portion is larger and the taper angle is smaller, the conductive ball can be stably positioned directly below the suction hole. Suitable shape.

However, when the suction head of the ball introduction portion having such a shape is used, the height from the lower surface of the suction head to the lower end of the conductive ball while holding the conductive ball (FIG. ) Is inevitably smaller. When a flux is applied to the conductive balls held in such a state by transfer, the flux easily adheres to not only the conductive balls but also the lower surface of the suction head. Therefore, the suction head used for the flux transfer has a shape that can maximize the height from the lower surface of the suction head to the lower end of the conductive ball when holding the conductive ball, that is, the depth of the ball introduction portion. A small one is suitable.

Next, the requirements of the suction head used for mounting the conductive ball on the work will be described. When the conductive ball is mounted on the electrode of the work, the contact condition between the lower end of the conductive ball and the electrode is constant due to the variation of the height of the conductive ball and the processing of the ball introduction part. No, partial crushing is inevitable. Therefore, a part of the conductive ball held by the suction head is pressed by the electrode, and the pressed conductive ball is pushed into the ball introducing portion. At this time, if the taper angle of the ball introduction portion is small, the conductive balls are easily pushed in, and after being pushed in, the transfer balls that are caught from the tapered surface and remain without detaching from the suction head even after the vacuum suction is released can be removed. Cause it to occur. Furthermore, in order to prevent the pressing load from being concentrated on some of the conductive balls at the time of pressing, the material of the suction head is one that is more likely to be elastically deformed by the load, that is, the Young's modulus ( Those having a small longitudinal modulus of elasticity are suitable.

In summary, as a suction head for picking up conductive balls by vacuum suction, it is desirable that the shape of the ball introduction portion is large and the taper angle is small in shape. In terms of the material, it is not particularly required that the Young's modulus is small. Therefore, a material such as a metal which is easier to process is desirable.

On the other hand, a suction head used for flux transfer and mounting on a work has a small depth of a ball introduction part, a large taper angle, and a small Young's modulus in terms of material. Things are desirable. In the present embodiment, as described above, the materials of the first suction head 4 and the second suction head 9 and the shape of the ball introduction portion are set so as to satisfy all of the above conditions.

Further, when the conductive balls 3 picked up by the first suction head 4 are transferred to the second suction head 9, as shown in FIG.
The diameter D of the conductive ball 3 and the depths d1 and d2 of the ball introduction portion are set so that an appropriate clearance c is secured between the suction heads 9 of the first embodiment.

The device for transferring conductive balls is configured as described above. A method for transferring conductive balls will be described below with reference to FIGS. 4, 5 and 6. FIG. 4
(A), (b), FIGS. 5 (a), (b), (c), FIG.
(A), (b), (c), and (d) show a method of mounting conductive balls in the order of steps.

First, as shown in FIG. 4A, the first suction head 4 is lowered with respect to the container 2, and the lower surface of the first suction head 4 is slightly lowered below the surface layer of the conductive balls 3. To enter. Then, the inside of the first suction head 4 is vacuum-suctioned, so that the conductive balls 3 are vacuum-sucked in the suction holes 4a. At this time, since the ball introduction portion of the suction hole 4a has a shape in which the taper angle of the tapered portion is small and the depth is large, one conductive ball 3 is quickly sucked into each suction hole 4a. Therefore, there is no suction failure in which a large number of conductive balls 3 are sucked and adhered around the suction holes 4a.

Thereafter, the first suction head 4 rises from the container 2 as shown in FIG. 4B, and is turned upside down by rotating in the direction of the arrow. Thereby, the first suction head 4
Is a state where the conductive ball 3 is held upward.

Next, the X-axis table 5 is driven to move the second suction head 9 above the first suction head 4, and FIG.
The first suction head 4 is lowered as shown in FIG. Then, as shown in FIG. 5B, the lower surface of the second suction head 9 approaches the conductive ball 3 held by the first suction head 4. In this state, the first suction head 4
When the vacuum suction of the second suction head 9 is started and the vacuum suction of the second suction head 9 is started, the conductive ball 3 is captured by the vacuum suction force of the suction hole 9a of the second suction head 9 and is suctioned by the suction hole 9a. Is done. Thereby, the conductive balls 3 are transferred from the first suction head 4 to the second suction head 9.

Thereafter, the second suction head 9 is moved above the flux applying section 11, and the second suction head 9 is lowered with respect to the container 12 as shown in FIG. The lower end of the sex ball 3 is brought into contact with the bottom of the container 12. Thereby, the flux 13 previously applied to the bottom surface of the container 12 with a predetermined film thickness is transferred to the conductive balls 3,
Thereafter, by raising the second suction head 9, a predetermined amount of the flux 13 is applied to the lower end of the conductive ball 3 as shown in FIG. 6B. At this time, since the depth of the ball introduction portion of the suction hole 9a of the second suction head 9 is set to be small, the height from the lower surface of the second suction head 9 to the lower end of the conductive ball 3 is secured. Therefore, the flux does not adhere to the lower surface of the second suction head 9.

Thereafter, the second suction head 9 moves onto the work positioning portion 14 and descends with respect to the work 16 as shown in FIG. Then, the conductive ball 3 coated with the flux 13 is brought into contact with the electrode 16 a of the work 16, and the vacuum suction is released in this state.
As shown in FIG. 6D, the conductive ball 3 is
Will be transferred to

At this time, the suction holes 9 of the second suction head 9
Since the taper angle of the ball introduction portion a is set to be large, when the conductive ball 3 is pressed against the work 16 by the second suction head 9, the conductive ball 3 is pushed into the suction hole 9a and bites. Therefore, no transfer error in which the conductive ball 3 remains in the suction hole 9a even after the vacuum suction is released does not occur. Since the second suction head 9 is made of a material having a small Young's modulus, the conductive balls 3
Is pressed against the work 16, the tapered surface of the suction hole 9a is easily deformed by the pressing load. Therefore, the pressing load does not act on some of the conductive balls 3 in a concentrated manner.

In the transfer step of the conductive balls described above, after the transfer of the conductive balls 3 to the second suction head 9 is completed, the first suction head 4 immediately moves to the next conductive ball 3. It is possible to move on to the pickup operation.
That is, according to the present embodiment, the tact time according to the present embodiment is smaller than the conventional conductive ball transfer method in which all steps of picking up the conductive ball, transferring the flux and mounting the conductive ball on the work are performed by a single suction head. Can be reduced to approximately half the time.

As described above, by providing two suction heads and making the shape and material of the suction holes of each suction head according to the characteristics required by the corresponding operation and function, the conventional method can solve the problem. It is possible to eliminate problems such as difficult suction errors and transfer errors, and contamination of conductive balls due to flux adhering to the suction head, as well as shorten tact time and greatly improve productivity. .

The present invention is not limited to the above embodiment. For example, in the above embodiment, an example is shown in which a flux is applied as an adhesive bonding material. The present invention can also be applied to a case where a different kind of adhesive bonding material such as cream solder or conductive paste is applied to the conductive ball depending on the situation. Furthermore, even when only pick-up and mounting are performed without applying the adhesive bonding material to the conductive balls, separate dedicated suction tools are used for the pick-up operation of the conductive balls and the mounting operation on the work. The effect of reducing pick-up errors and mounting errors, shortening the tact time, and improving productivity is obtained.

[0041]

According to the present invention, two dedicated suction heads are provided: a first suction head for picking up conductive balls from a ball supply unit by vacuum suction, and a second suction head for mounting conductive balls on a work. Since the suction heads are provided, the shape and material of each suction head can be adapted to the characteristics required by the corresponding operation and function, and pickup errors and mounting errors can be reduced. Takt time can be reduced.

When the adhesive bonding material is applied to the conductive balls at the same time, the pickup head for pickup and the transfer head for transferring the adhesive bonding material are separated from each other, so that the suction head for pickup is separated. It is possible to prevent the adhesive bonding material from adhering to the lower surface of the semiconductor device, reduce pickup errors and mounting errors caused by the adhesion of the adhesive bonding material, and improve the use yield of the conductive balls.

[Brief description of the drawings]

FIG. 1 is a front view of a conductive ball transfer device according to an embodiment of the present invention.

FIG. 2A is a sectional view of a suction head of a conductive ball transfer device according to one embodiment of the present invention; FIG. 2B is a sectional view of a suction head of a conductive ball transfer device according to one embodiment of the present invention; Sectional view

FIG. 3A is an enlarged sectional view of a suction head of a conductive ball transfer device according to one embodiment of the present invention; FIG. 3B is a suction head of a conductive ball transfer device according to one embodiment of the present invention; (C) Enlarged cross-sectional view of the suction head of the conductive ball transfer device according to one embodiment of the present invention.

FIG. 4A is an explanatory view of a step of a method for transferring a conductive ball according to an embodiment of the present invention. FIG. 4B is an explanatory view of a step of a method of transferring a conductive ball according to an embodiment of the present invention.

FIG. 5 (a) is a process explanatory view of a method for transferring conductive balls according to one embodiment of the present invention. (B) is a process explanatory view of a method for transferring conductive balls according to one embodiment of the present invention. FIG. 4 is a process explanatory view of a method for transferring conductive balls according to an embodiment of the present invention.

FIG. 6A is an explanatory diagram of a process of a method for transferring a conductive ball according to an embodiment of the present invention. FIG. 6B is an explanatory diagram of a process of a method for transferring a conductive ball according to an embodiment of the present invention. (D) Process explanatory diagram of a method for transferring conductive balls according to one embodiment of the present invention (d) Process explanatory diagram of a method for transferring conductive balls according to an embodiment of the present invention

[Explanation of symbols]

 Reference Signs List 1 ball supply unit 2 container 3 conductive ball 4 first suction head 4a suction hole 5 X-axis table 8 Z-axis table 9 second suction head 9a suction hole 11 flux application unit 13 flux 14 positioning unit 16 work

Claims (8)

[Claims] 1. A ball supply unit for supplying a conductive ball,
A plurality of suction holes are provided on the lower surface, and a first suction head for picking up conductive balls by vacuum suction from the ball supply unit, and a plurality of suction holes are provided on the lower surface, and the conductive balls are supplied from the first suction head. A second suction head for receiving, moving means for moving the second suction head,
Lifting means for vertically moving the second suction head with respect to the work so as to mount the conductive ball held by the second suction head on the work. Transfer equipment. 2. The conductive ball transfer apparatus according to claim 1, further comprising an application unit for applying an adhesive bonding material to the conductive balls held by the second suction head. 3. The conductive ball transfer apparatus according to claim 1, wherein the first suction head and the second suction head have the same suction hole arrangement in at least a part thereof. 4. A taper angle of a ball introduction portion of a suction hole provided in said first suction head is smaller than a taper angle of a ball introduction portion of a suction hole provided in said second suction head. The conductive ball transfer device according to claim 1, wherein: 5. The suction head according to claim 1, wherein a depth of the ball introduction portion of the suction hole provided in the first suction head is greater than a depth of the ball introduction portion of the suction hole provided in the second suction head. The conductive ball transfer device according to claim 1. 6. The conductive ball according to claim 1, wherein a Young's modulus of a material of a lower surface of the first suction head is larger than a Young's modulus of a material of a lower surface of the second suction head. Transfer equipment. 7. A step of vacuum-sucking and picking up the conductive balls stored in the ball supply section by a first suction head having a plurality of suction holes on a lower surface, and holding the conductive balls by the first suction head. Transferring the conductive ball to a second suction head provided with a plurality of suction holes on the lower surface;
Moving the second suction head over the work, moving the second suction head up and down relative to the work, and mounting the conductive ball held by the second suction head on the work. How to transfer a sex ball. 8. The method for transferring conductive balls according to claim 7, further comprising the step of applying an adhesive bonding material to the conductive balls held by the second suction head.