JP2005044978A - Conductive ball mounting device - Google Patents

Abstract

The present invention provides an apparatus for adsorbing conductive balls on an array plate efficiently and accurately.
A conductive ball mounting device for mounting a conductive ball on an electrode of a plurality of electronic components formed on a substrate by means of a suction tool, wherein the mounting is performed for positioning the substrate on which the plurality of electrodes are formed. A conductive ball supply unit that accommodates the plurality of conductive balls, a charging device that charges the conductive balls, and a plurality of connection terminals that are connected to a vacuum source and formed on the substrate on the suction surface A plurality of suction holes are formed in the same arrangement, and the conductive balls are sucked and taken out from the conductive ball supply part to the suction holes, and the conductive balls are mounted on the connection terminals of the substrate positioned in the mounting part. A conductive ball mounting device comprising at least an array plate.
[Selection] Figure 1

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a conductive ball mounting device, and more particularly to a device that holds fine conductive balls on an array plate and collectively mounts them on electrodes of an electronic component such as a printed board or a chip.
[0002]
[Prior art]
In recent years, ball bumps using minute metal balls have been used for electrical connection of semiconductor chips. By using the ball bumps, it is possible to obtain a number of merits such as downsizing the package and increasing the number of pins. A bump forming technique using such a fine metal ball is described in, for example, (Patent Document 1). In the bump forming method described in the above document, at least a metal ball group corresponding to one semiconductor chip is sucked and held. In order to suck and hold a plurality of metal ball groups, a ball array plate in which suction holes are formed at all positions corresponding to bump formation positions on the semiconductor chip is used. After the fine metal balls are attracted and held on the ball array plate, the ball array plate is transported to the mounting stage and mounted on the mounted portion. According to this method, the uniformly formed minute metal balls can be collectively mounted at the bump forming position, so that it is possible to easily and efficiently form a ball bump with little variation and high shape accuracy.
[0003]
By the way, recently, the miniaturization of semiconductor devices has progressed, and the wiring pitch of 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, the arrangement of one semiconductor chip (on a chip basis) increases the number of repetitions of the process, and is disadvantageous in terms of cost and time. For this reason, 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.
[0004]
FIG. 4 is a schematic view of an apparatus for mounting ball bumps on all electrodes corresponding to a plurality of chips on a wafer as a technical example, as viewed from the side. The conductive ball 14 is introduced into the ball storage container 16 on the ball supply device 22, and the distance from the ball storage container 16 can be arbitrarily adjusted by a driving device (not shown) connected to the ball mounting head 12. . The ball mounting head 12 is moved closer to the ball storage container 16 side while suctioning from the ball storage container 16 side to the inside of the ball mounting head 12 through the suction holes 12b of the array plate by a vacuum source (not shown). The conductive balls 14 are arranged on the arrangement plate 12a by a suction force generated by vacuum exhaust from the adsorption holes 12b of the arrangement plate. After the conductive balls 14 are mounted on the array plate 12a, the ball mounting head 12 is moved along the guide rail 10 onto the ball mounting portion 30. The ball mounting unit 30 includes a ball mounting stage 28 and a ball mounting substrate 26 such as a silicon wafer installed on the ball mounting stage 28. The ball mounting substrate 26 is fixed on the ball mounting stage 28 by a method such as vacuum suction. Further, a fixing material such as a flux (not shown) is applied to the upper electrode disposed on the ball mounting substrate 26, and the ball once mounted on the upper electrode is temporarily fixed at that position. ing. After the ball mounting portion 30 is positioned in the horizontal direction so that the conductive ball 14 is mounted on a predetermined electrode on the mounting substrate 26, the ball mounting portion 30 and the mounting substrate 26 are brought close to each other on the array plate 12a. The arranged conductive balls 14 are pressed onto predetermined electrodes on the mounting substrate 26. Thereafter, the suction inside the ball mounting head 12 is stopped, and the inside of the ball mounting head 12 is adjusted to atmospheric pressure or a pressure higher than atmospheric pressure. Further, after that, the ball mounting head 12 is pulled away from the mounting substrate 26 to complete the mounting of the conductive ball 14 on the mounting substrate 26.
[0005]
[Patent Document 1] Japanese Patent Laid-Open No. 7-153765 [0006]
[Problems to be solved by the invention]
By the way, in this type of ball array mounting technology, in the method of fixing the balls in the suction holes of the array plate by exhausting into the mounting head, the exhaust speed into the mounting head is increased to increase the suction force. As a result, the airflow is disturbed in the space between the array plate and the ball supply unit, and rather, the phenomenon that the efficiency of adsorption to the adsorption holes of the balls is reduced, and as a result, all the adsorption holes in the array plate are observed. It takes a long time to complete the ball arrangement. This phenomenon becomes more prominent as the area of the array plate increases.
[0007]
In addition, in the process of mounting the conductive balls on the array plate, there is a problem of so-called surplus ball generation in which the conductive balls (14a) adhere to other than the suction holes as shown in FIG.
[0008]
In view of such circumstances, an object of the present invention is to provide an apparatus for adsorbing conductive balls on an array plate efficiently and accurately.
[0009]
[Means for Solving the Problems]
The conductive ball mounting device according to the present invention is a conductive ball mounting device in which a conductive ball is mounted on an electrode of a plurality of electronic components formed on a substrate by an adsorption tool, wherein the plurality of electrodes are formed. A mounting portion for positioning the substrate, a conductive ball supply portion for storing the plurality of conductive balls, a charging device for charging the conductive balls, and a vacuum source, and formed on the substrate on the suction surface. A plurality of suction holes are formed in the same arrangement as the plurality of connection terminals, and the conductive balls are sucked and taken out from the conductive ball supply part to the suction holes, on the connection terminals of the substrate positioned in the mounting part. It has at least an array plate on which conductive balls are mounted.
[0010]
Moreover, it is preferable that the said conductive ball supply part is provided with the means to jump the said conductive ball by vibration.
In addition, the charging device includes an ionizer that charges the conductive balls introduced into the conductive ball supply unit, or generates a potential difference between the conductive ball supply unit and the array plate. It is preferable that a means for applying is provided. Furthermore, the maximum value of the potential difference is within a range of 10 to 1000 V, and the potential difference applied between the conductive ball supply unit and the array plate is one or both of a DC voltage and an AC voltage. And a means capable of changing with time the magnitude of the DC voltage applied between the conductive ball supply unit and the array plate, the conductive ball supply unit and the array plate Means for changing the magnitude and frequency of the alternating voltage applied between them with time, and means for arbitrarily releasing the electrical connection between the conductive ball supply unit and the array plate More preferably.
Further, it is more preferable that the conductive balls are mounted together.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
The present invention includes a charging device for the conductive ball introduced into the ball supply device. As a charging device, as shown in FIG. 1, a system for applying a voltage between a ball container and an array plate on the ball supply device, or as an ionizer for conductive balls on the ball supply device as shown in FIG. There are systems that irradiate positive or negative ions.
[0012]
First, FIG. 1 will be described. FIG. 1 is a schematic view of a conductive ball mounting apparatus shown as a first example of the present invention as viewed from the side. A positive DC voltage is applied to the ball storage container 16 on the ball supply device 22 by a DC power supply 24, and a negative voltage is applied to the ball mounting head 12 including the array plate 12a. In FIG. 1, a DC power source is used, but the present invention is not limited to this, and an AC voltage or a voltage in which DC and AC are superimposed may be used. Any power source that can apply a potential difference between them may be used. The distance between the ball mounting head 12 and the ball storage container 16 can be arbitrarily adjusted by a driving device (not shown). The driving device is connected to at least one of the ball mounting head 12 and the ball storage container 16. Note that the negative electrode side of the DC power supply 24 is grounded and has a ground potential. The conductive ball 14 on the ball storage container 16 has a positive potential of the same magnitude as that of the ball storage container 16 and receives an electrical attractive force from the array plate 12a. However, the value of the voltage of the DC power supply 24 is set so that the electric attractive force does not exceed the gravity applied to the conductive ball 14. That is, it is desirable that the maximum value of the potential difference is in the range of 10 to 1000V.
[0013]
Next, when an appropriate vibration is continuously applied to the ball storage container 16 by the shaker 20, the conductive balls 14 continuously jump from the ball storage container 16 toward the array plate 12a. With the conductive ball 14 jumping, suction from the ball storage container 16 side to the inside of the ball mounting head 12 is performed through the suction holes 12b of the array plate by a vacuum source (not shown). The conductive balls 14 jumped by applying continuous vibration approach the array plate 12a. However, when the distance between the conductive balls 14 and the array plate 12a is equal to or less than a certain distance, the conductive balls 14 and the array plate 12a. The electrically attractive balls 14 are efficiently arranged on the array plate 12a due to the effect of increasing the electric attractive force between 12a and applying the suction force by vacuum exhaust from the suction holes 12b of the array plate 12a. The diameter of the suction hole 12b is set to be smaller than the diameter of the conductive ball 14, and as shown in FIG. 3, the conductive ball 14 is stationary while being sucked on the surface of the array plate 12a. However, in the process described above, there are cases where surplus balls 14a as shown in FIG. 5 exist, and these need to be removed.
[0014]
Hereinafter, a method for removing excess balls will be described. After the conductive balls 14 are mounted on the array plate 12a, the ball mounting head 12 and the ball mounting head 12 are stopped while applying vibration to the ball mounting head 12 and applying a DC voltage between the ball mounting head 12 and the ball storage container 16. The distance from the ball storage container 16 is changed to a certain value. As a result, the balance between gravity and electrostatic force in the direction of the ball container 16 changes with respect to the surplus balls 14a. Due to this effect, only the surplus balls 14 a are removed from the array plate 12 a and dropped into the ball storage container 16. At this time, the same force also acts on the conductive balls 14b attracted to the suction holes 12b of the array plate 12a, but does not separate from the array plates 12a due to the suction force from the suction holes 12b. Furthermore, an electrical attractive force toward the ball mounting head 12 is generated for the conductive ball 14 c existing on the ball storage container 16, but is applied between the ball mounting head 12 and the ball storage container 16. Since the electric attractive force due to the voltage is set so as not to exceed the gravity of the conductive ball 14c itself, the conductive ball 14c existing on the ball storage container 16 is not newly attracted to the array plate 12a. Further, as means other than the means for changing the distance between the mounting head and the ball storage container, the magnitude of the DC voltage applied between the conductive ball supply unit and the array plate can be changed with time. Or a means capable of changing the magnitude and frequency of the AC voltage applied between the conductive ball supply unit and the array plate with time. The ball can be removed.
[0015]
As described above, after the surplus balls 14 a are removed from the array plate 12 a, the ball mounting head 12 is moved along the guide rail 10 onto the ball mounting portion 30. The ball mounting unit 30 includes a ball mounting stage 28 and a ball mounting substrate 26 such as a silicon wafer installed on the ball mounting stage 28. The ball mounting substrate 26 is fixed on the ball mounting stage 28 by a method such as vacuum suction. Further, a fixing material such as a flux (not shown) is applied to the upper electrode (not shown) on the ball mounting substrate 26, and the ball once mounted on the upper electrode is temporarily fixed to the place. Yes. After the ball mounting portion 30 is positioned in the horizontal direction so that the conductive ball 14 is mounted on a predetermined electrode on the mounting substrate 26, the ball mounting head 12 and the mounting substrate 26 are brought close to each other on the array plate 12a. The conductive ball 14 disposed on the mounting substrate 26 is pressed onto a predetermined electrode on the mounting substrate 26. Thereafter, the suction inside the ball mounting head 12 is stopped, and the inside of the ball mounting head 12 is adjusted to atmospheric pressure or a pressure higher than atmospheric pressure. Thereafter, the ball mounting head 12 is pulled away from the mounting substrate 26, thereby completing the mounting of the conductive ball 14 on the mounting substrate 26.
[0016]
Next, FIG. 2 will be described. FIG. 2 is a schematic view of the conductive ball mounting apparatus shown as the second example of the present invention as seen from the side. In this example, an ionizer 32 that charges static electricity is disposed on the ball storage container 16 on the ball supply device 22. In the following description, it is assumed that the ionizer 32 that gives negative static electricity is arranged. Even if this is an ionizer that gives positive static electricity, the effect is exactly the same. An insulator 18 is disposed between the shaker 20 and the ball storage container 16, so that charges due to static electricity applied to the ball storage container 16 do not flow to the shaker 20 side. On the other hand, the ball mounting head 12 is grounded and has a ground potential. Due to the ion irradiation from the ionizer 32, the ball container 16 and the conductive ball 14 are negatively charged and receive an electric attractive force from the array plate 12a at the ground potential. However, by adjusting the ion irradiation amount irradiated from the ionizer, the electric attractive force is in a range not exceeding the gravity of the conductive ball 14. Next, when appropriate vibration is continuously applied to the ball storage container 16, the conductive balls 14 continuously jump from the ball storage container 16 toward the array plate 12a. With the conductive ball 14 jumping, suction from the ball storage container 16 side to the inside of the ball mounting head 12 is performed through the suction holes 12b of the array plate by a vacuum source (not shown). By applying continuous vibration, the jumped conductive balls 14 approach the array plate 12a. However, when the distance between the conductive balls 14 and the array plate 12a is equal to or less than a predetermined distance, the conductive balls 14 and the array plate 12a. The electrically attractive balls 14 are efficiently arranged on the array plate 12a by the effect of increasing the electric attractive force between the 12a and applying the suction force by the vacuum exhaust from the suction holes 12b of the array plate. The diameter of the suction hole 12b is set to be smaller than the diameter of the conductive ball 14, and as shown in FIG. 3, the conductive ball 14 stops in a state of being sucked on the surface of the array plate 12a. However, in the process described above, there are cases where the surplus balls 14a as shown in FIG. 5 exist, and these need to be removed.
[0017]
Hereinafter, a method for removing excess balls will be described. After the conductive balls 14 are mounted on the array plate 12a, the vibration to the ball mounting head 12 is stopped, and the distance between the ball mounting head 12 and the ball storage container 16 is brought close to a certain value. Thereby, an electrostatic force in the direction of the ball storage container 16 having a negative potential acts on the surplus balls 14a having the ground potential. Due to the effect of the gravity of the surplus balls themselves on this electrostatic force, only the surplus balls are removed from the array plate 12a and dropped into the ball storage container 16. At this time, the same force also acts on the conductive balls 14b adsorbed in the adsorption holes 12b of the array plate, but does not leave the array plate 12a due to the suction force from the adsorption holes. Further, an electrically attractive force toward the ball mounting head 12 is generated for the negatively charged conductive ball 14c existing on the ball storage container 16, and this electric attractive force is applied to the conductive ball 14c itself. Since it is smaller than the applied gravity, the conductive balls 14c existing on the ball storage container 16 are not attracted to the array plate 12a.
[0018]
As described above, the surplus balls 14a are removed from the array plate 12a. The procedure from the subsequent movement of the ball mounting head 12 onto the ball mounting portion 30 to the mounting of the conductive ball 14 onto the mounting substrate 26 is the same as in the first example.
[0019]
The conductive balls may be mounted on the mounting substrate for each chip formed on the silicon wafer or the like. However, from the viewpoint of throughput, all the electrodes formed on the silicon wafer should be mounted at once. Is desirable.
[0020]
【Example】
An embodiment of the present invention will be described with reference to FIG.
[0021]
A DC voltage of 1000 V is applied to the stainless steel ball storage container 16 on the ball supply device 22 by a DC power supply 24, while the ball mounting head 12 including the array plate 12a on the negative electrode side is grounded. . The array plate 12a is made of stainless steel, and approximately 100,000 circular suction holes having a diameter of 60 μm are arrayed at regular intervals. A driving device (not shown) is connected to the ball mounting head 12, and the position can be arbitrarily adjusted in the vertical direction. About 1 million conductive balls 14 made of solder balls having a diameter of 100 μm are introduced onto the ball container 16 by a device (not shown). Next, ultrasonic vibration is continuously applied to the ball storage container 16 by the vibrator 20, and the conductive balls 14 are continuously jumped from the ball storage container 16 toward the array plate 12a. With the conductive ball 14 jumping, suction is performed by a vacuum pump (not shown) from the ball container 16 side to the ball mounting head 12 through the suction hole 12b of the array plate while maintaining a relative pressure of −100 mmHg. Initially, the distance between the array plate 12a and the ball storage container 16 is set to 100 mm, but the distance between the array plate 12a and the ball storage container 16 is gradually reduced from there to become 10 mm. Let stand for 30 seconds. As a result, the conductive balls 14 are attracted to almost all the suction holes 12b of the array plate. Thereafter, the vibration exciter 20 is stopped, and the distance between the array plate 12a and the ball storage container 16 is brought close to 5 mm. As a result, the conductive balls 14 other than the adsorbing holes 12b of the array plate are removed from the array plate 12a. Thereafter, the ball mounting head 12 is raised, and the electrical connection between the DC power supply 24 and the ball mounting head 12 is disconnected. The ball mounting head 12 moves on the ball mounting portion 30 along the guide rail 10. On the ball mounting portion 30, a silicon wafer is disposed and fixed as a ball mounting substrate 26 by vacuum suction. A flux is applied to the upper electrode formed on the ball mounting substrate 26 by a device (not shown). After the ball mounting portion 30 is positioned in the horizontal direction so as to be in a predetermined position, the ball mounting portion 30 is lowered and brought close to the ball mounting substrate 26 so that the conductive balls 14 arranged on the array plate 12a are moved. It presses on the predetermined electrode on the mounting substrate 26. Thereafter, suction inside the ball mounting head 12 is stopped, and the inside of the ball mounting head 12 is brought to atmospheric pressure. Thereafter, the ball mounting head 12 is pulled away from the mounting substrate 26, whereby the mounting of the conductive ball 14 on the ball mounting substrate 26 is completed.
[0022]
【The invention's effect】
As described above, according to the present invention, in this kind of ball arraying apparatus, particularly for mounting a large number of fine conductive balls on a large-sized mounting substrate such as batch mounting on a silicon wafer, the array plate Even if the amount of suction from the container is kept below a certain value, conductive balls can be arranged on the array plate efficiently and in a short time without generating excess balls, which greatly increases the yield and productivity of conductive balls. It has the advantage that it can be improved.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a conductive ball mounting device using a DC power source as a charging device, which is a first example of the present invention.
FIG. 2 is a schematic view of a conductive ball mounting device using an ionizer as a charging device, which is a second example of the present invention.
FIG. 3 is a diagram showing a state of adsorption of conductive balls from a ball storage container to an array plate.
FIG. 4 is a schematic view of a conventional conductive ball mounting apparatus.
FIG. 5 is a view showing a state of attachment of surplus balls on the array plate.
[Explanation of symbols]
10 guide rail 12 ball mounting head 12a array plate 12b suction hole 14 conductive ball 14a surplus ball 14b conductive ball 14c adsorbed in the suction hole conductive ball 16 remaining on the ball storage container 16 ball storage container 18 insulator 20 addition Vibrator 22 Ball supply device 24 DC power supply 26 Ball mounting substrate 28 Ball mounting stage 30 Ball mounting portion 32 Ionizer

Claims (10)

A conductive ball mounting device for mounting a conductive ball on an electrode of a plurality of electronic components formed on a substrate by a suction tool, the mounting portion positioning the substrate on which the plurality of electrodes are formed, and a plurality of A conductive ball supply unit containing the conductive ball, a charging device for charging the conductive ball, a vacuum source, and a plurality of electrodes in the same arrangement as the plurality of electrodes formed on the substrate on the suction surface An adsorption hole is formed, and at least an array plate for adsorbing and removing the conductive ball from the conductive ball supply unit to the adsorption hole and mounting the conductive ball on the electrode of the substrate positioned in the mounting unit is provided. A conductive ball mounting device characterized by the above. The conductive ball mounting device according to claim 1, wherein the conductive ball supply unit includes means for jumping the conductive ball by vibration. The conductive ball mounting device according to claim 1, wherein the charging device includes an ionizer that charges the conductive ball introduced into the conductive ball supply unit. The conductive ball mounting device according to claim 1, wherein the charging device includes means for applying a potential difference between the conductive ball supply unit and the array plate. The conductive ball mounting apparatus according to claim 4, wherein a maximum value of the potential difference is in a range of 10 to 1000V. 6. The conductive ball mounting apparatus according to claim 4, wherein a potential difference applied between the conductive ball supply unit and the array plate is one or both of a DC voltage and an AC voltage. 7. The conductive ball mounting device according to claim 6, further comprising means capable of changing the magnitude of the DC voltage applied between the conductive ball supply unit and the array plate with time. 7. The conductive ball mounting device according to claim 6, further comprising means capable of changing with time the magnitude and frequency of the alternating voltage applied between the conductive ball supply unit and the array plate. The conductive ball mounting device according to any one of claims 4 to 8, further comprising means for arbitrarily releasing an electrical connection between the conductive ball supply unit and the array plate. 2. The conductive ball mounting apparatus according to claim 1, wherein the mounting of the conductive balls is a batch mounting.

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