JP2010106321A - Apparatus and method of producing fine particle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production apparatus and a production method of fine particles for producing uniform fine particles, for example, fine metal spheres having a narrow particle size distribution and high sphericity, such as solder balls.
SOLUTION: A nozzle 1 that causes a liquid 11 to flow downward, a vibration device 4 that vibrates the nozzle 1, a nozzle base 2 that slidably holds the nozzle 1, and a liquid storage tank 3 are provided. The nozzle path 20 is connected to the liquid outlet 22 and circulates the liquid. The nozzle base 2 has the base path 30 that is connected from the liquid storage tank 3 to the nozzle 1 and circulates the liquid. The nozzle path 20 and the base path 30 communicate with each other. Thus, the apparatus for producing fine particles is characterized in that the liquid can be circulated. By causing the liquid 11 to flow out from the liquid outlet 22 of the nozzle 1 while vibrating the nozzle 1 by the vibration device 4, the liquid that has flowed out can be separated into fine particles. Since the supply system for supplying the liquid to the nozzle is separated from the vibrating nozzle, the size of the generated fine particles is made uniform.
[Selection] Figure 1

Description

  The present invention relates to an apparatus and a method for producing fine particles for producing fine metal spheres having a narrow particle size distribution and a high sphericity, such as uniform fine particles, such as solder balls, from a liquid.

  When a semiconductor device is assembled using a semiconductor device mounting technology such as CSP (chip size package) or BGA (ball grid array), fine metal balls such as solder balls are used. As a fine metal sphere used for assembling a semiconductor device, a fine metal sphere of several tens to several hundreds of μm is used. The metal sphere is required to have a uniform sphere diameter and extremely stable accuracy.

  In addition to fine metal spheres, in the production of granular drug or ceramic raw materials, it is necessary to produce fine particles in which the size and shape of the granules are precisely controlled.

  As a method for producing fine metal spheres, Patent Document 1 discloses that the metal itself is a small piece in which the metal is adjusted to a predetermined volume, the metal piece is poured into a liquid held above the melting point of the metal, heated and melted, and the liquefied metal itself Spheroidized in the liquid by the surface tension of the liquid, the temperature of the lower part of the liquid is set below the melting point of the metal, and the spheroidized metal descends to the lower part of the liquid and solidifies. Further, in Patent Document 2, a molten metal is injected into a measuring device having a predetermined volume and measured, and the measured molten metal is discharged from the measuring device and solidified to form a minute metal sphere. A manufacturing method is described. However, these methods require a device for making a metal piece, and when the size of the metal sphere becomes small, there is a problem in ensuring accuracy in producing a piece having a constant volume.

  The one disclosed in Patent Document 3 is provided with a plurality of fine holes (orifices) at the bottom of a crucible, filled with molten metal in the crucible, and vibrated with a disk immersed in the molten metal using the piezoelectric element as a drive source, thereby This is a method in which vibration energy is transmitted to the molten metal itself, and the molten metal flowing out from the microholes at the bottom is made into fine droplets. Such a method is known as Uniform Droplet Spray method (uniform droplet method, UDS method). Hereinafter referred to as “UDS method”. A similar method is also disclosed in Patent Document 4, for example.

  Patent Document 5 has a vibrating nozzle head connected to a vibration generator and having at least one nozzle, and a supply line provided between the liquid-phase supply container and the nozzle head. A method for generating droplets is disclosed. Silver nitrate droplets are manufactured using the embodiment shown in FIG. 1 of the same document, and soft solder alloy droplets are manufactured using the embodiment shown in FIG. According to FIGS. 1 and 2, the supply line has a helical portion.

JP-A-7-252510 JP 2000-144215 A US Pat. No. 5,266,098 JP 2001-226705 A JP-A-4-227043

  As described in Patent Documents 3 and 4, in a method of producing a micro droplet while having a molten metal outflow nozzle at the bottom of a molten metal container filled with molten metal and flowing out the molten metal from the nozzle while applying vibration to the molten metal. The vibration that the molten metal receives at the nozzle outlet is weak, and the power for cutting the jet flowing out from the nozzle is not sufficient, and the vibration power can only play an auxiliary role in cutting the liquid flow. For this reason, the volume of the droplet after cutting is not constant, and a droplet having a uniform particle size cannot be produced. Moreover, since it is necessary to provide a vibration generator on the top part of a molten metal container, it has the fault that the whole height of an apparatus becomes high.

  In addition, the method described in Patent Document 5 has a problem in that the size of the produced droplets is non-uniform and the spherical diameter accuracy of the fine metal spheres varies.

  It is an object of the present invention to provide a manufacturing apparatus and a manufacturing method of fine particles for producing fine metal spheres having a narrow particle size distribution and high sphericity, such as uniform fine particles such as solder balls.

  In the method described in Patent Document 5, a supply line is connected to the vibrating nozzle head, and when the vibrating nozzle head is vibrated, the connected supply line also vibrates. For this reason, it has been found that the vibration energy from the vibration generator is not fully utilized for the generation of droplets, which causes non-uniformity in droplet size. The same was true if a spiral portion was provided in the supply line.

This invention is made | formed based on the said knowledge, The place made into the summary is as follows.
(1) It has a nozzle 1 that causes the liquid 11 to flow downward, a vibration device 4 that vibrates the nozzle 1, a nozzle base 2 that slidably holds the nozzle 1, and a liquid storage tank 3. The nozzle 1 is a liquid The nozzle path 20 is connected to the outlet 22 and circulates the liquid. The nozzle base 2 has the base path 30 that is connected from the liquid storage tank 3 to the nozzle 1 and circulates the liquid. The nozzle path 20 and the base path 30 communicate with each other. A device for producing fine particles characterized in that a liquid can be distributed.
(2) It has the connecting rod 5 which connects the nozzle 1 and the vibration apparatus 4, The manufacturing apparatus of the microparticle as described in said (1) characterized by the above-mentioned.
(3) The end of the nozzle path 20 opposite to the liquid outlet 22 opens to the sliding surface 7 between the nozzle 1 and the nozzle gantry 2, and the gantry path 30 is disposed in the nozzle gantry 2 and The apparatus for producing fine particles according to the above (1) or (2), wherein the apparatus opens to a sliding surface 7 with the nozzle base 2.
(4) The apparatus for producing fine particles according to any one of (1) to (3), wherein the liquid 11 is a molten metal.
(5) By using the microparticle manufacturing apparatus according to any one of (1) to (3) above, the liquid 11 is caused to flow out from the liquid outlet 22 of the nozzle 1 while the nozzle 1 is vibrated by the vibration device 4. A method for producing fine particles, wherein the liquid that has flowed out is separated into fine particles.
(6) The method for producing fine particles according to (5) above, wherein the liquid 11 is a molten metal, and the separated fine particles are solidified to form fine metal spheres.

  In the UDS method in which a liquid is caused to flow out from a nozzle while forming a uniform droplet to form a uniform droplet, vibration is applied to the nozzle itself that causes the liquid to flow out, and the supply system that supplies the liquid to the nozzle vibrates. Therefore, the vibration energy from the vibration generator is fully utilized for the generation of fine particles, and the size of the generated fine particles is made uniform.

  The apparatus and method for producing fine particles of the present invention can be used for producing fine metal spheres using various metals or granulating raw materials for granular drugs and ceramics. Here, a case where a solder ball is manufactured will be described below as an example.

  The present invention will be described with reference to FIGS.

  The apparatus for producing fine particles according to the present invention includes a nozzle 1 that causes liquid 11 to flow downward, a vibration device 4 that vibrates nozzle 1, nozzle mount 2 that slidably holds nozzle 1, and liquid storage tank 3. Have.

  The nozzle 1 has a liquid outlet 22 below the nozzle 1 and is slidably held on the nozzle base 2. The nozzle 1 is slidable in the vertical direction while being held by the nozzle base 2. The nozzle 1 can be held in the nozzle gantry 2 by forming the nozzle 1 in a cylindrical shape and forming the nozzle holding portion 6 that is an opening for holding the cylindrical nozzle in the nozzle gantry 2. The vibration device 4 is connected to the nozzle 1, and the nozzle 1 can be vibrated by the vibration device 4. As the vibration device 4, a piezoelectric element is used. The vibration direction of the nozzle 1 by the vibration device 4 coincides with the sliding direction of the nozzle 1 held on the nozzle base 2. The vibration device 4 can be directly connected to the nozzle 1, but may be connected using a connecting rod 5 that connects the nozzle 1 and the vibration device 2.

  In the example shown in FIG. 1, the nozzle 1 has a cylindrical shape, and a liquid outlet 22 is opened at the lower end of the cylinder. The nozzle holding part 6 arranged on the nozzle gantry 2 forms a cylindrical opening having the same diameter as the cylindrical part of the nozzle 1 in the vertical direction, and the nozzle 1 is arranged in the nozzle holding part 6 so that the nozzle gantry 2 Can hold the nozzle 1 slidably in the vertical direction. A piezoelectric element is used as the vibration device 4, and the nozzle 1 and the vibration device 4 are connected by a steel connecting rod 6. The vibration device 4, the connecting rod 6, and the nozzle 1 are arranged in the vertical direction, and the nozzle 1 vibrates in the vertical direction by excitation by the vibration device 4. A frequency band of several kHz is used as the frequency band.

  When applied to the manufacture of solder balls, the liquid storage tank 3 stores molten solder. In the liquid storage tank 3, the molten solder is held at a temperature higher than the melting point by a predetermined temperature. In the example illustrated in FIG. 1, the liquid storage tank 3 includes a heating device in which a band heater is wound, and the temperature of the molten solder can be maintained at a temperature higher than the melting point by 100 ° C. or more.

  The nozzle 1 has a nozzle path 20, and the nozzle path 20 is connected to a liquid outlet 22 below the nozzle and allows the liquid 11 to flow. The nozzle gantry 2 has a gantry path 30, and the gantry path 30 is connected to the nozzle from the liquid storage tank 3, and the liquid 11 is circulated from the liquid storage tank 3. The nozzle path 20 and the gantry path 30 communicate with each other to allow the liquid 11 to flow. The liquid 11 stored in the liquid storage tank 3 passes through the gantry path 30 disposed in the nozzle gantry 2, further passes through the nozzle path 20 included in the nozzle, and finally from the liquid outlet 22 below the nozzle. leak.

  The nozzle path 20 and the gantry path 30 need to communicate with each other so that liquid does not leak from the path. Preferably, in the present invention, the liquid inlet 21, which is the end of the nozzle path 20 opposite to the liquid outlet 22, opens in the sliding surface 7 between the nozzle 1 and the nozzle gantry 2, and the gantry path 30 is the nozzle gantry 2. The liquid outlet 32 may be opened on the sliding surface 7 between the nozzle 1 and the nozzle mount 2. On the sliding surface 7 of the nozzle 1 and the nozzle gantry 2, the liquid inlet 21 of the nozzle path 20 and the liquid outlet 32 of the gantry path 30 face each other. Thereby, the nozzle path | route 20 and the mount path | route 30 can be connected. Further, by providing a seal member 8 such as an O-ring on the sliding surface 7 of the nozzle 1 and the nozzle gantry 2, the sliding surface 7 of the nozzle 1 and the nozzle gantry 2 is hermetically sealed, thereby the nozzle path 20 and the gantry. Liquid leakage from the communicating portion of the path 30 can be prevented.

  In the example shown in FIGS. 1 and 2, a liquid outlet 22 is disposed below the cylindrical nozzle 1, and a nozzle path 20 is formed along the axis of the nozzle starting from the liquid outlet 22. Then, the direction is changed in the radial direction of the nozzle, and the liquid inlet 21 is formed by opening the sliding surface 7 between the nozzle 1 and the nozzle mount 2. On the other hand, the gantry path 30 is disposed inside the nozzle gantry 1, and one end of the gantry path 30 opens on the sliding surface 7 between the nozzle 1 and the nozzle gantry 2 and opens the liquid outlet 32. Form. On the sliding surface 7 of the nozzle 1 and the nozzle gantry 2, the liquid inlet 21 of the nozzle path 20 and the liquid outlet 32 of the gantry path 30 face each other, and the nozzle path 20 and the gantry path 30 communicate at this position. . The other end of the gantry path 30 opens as a liquid inlet 31 at the bottom of the liquid storage tank 3, and the molten solder stored in the liquid storage tank 3 is led to the liquid outlet 32 via the gantry path 30. The molten solder flows into the communicating nozzle path 20 and finally flows out from the liquid outlet 22 of the nozzle 1. An O-ring is disposed as a seal member 8 above and below the outer circumference of the cylindrical shape of the nozzle. As a result, leakage of molten solder from the sliding surface 7 between the nozzle 1 and the nozzle mount 2 can be prevented. it can. In order to keep the temperature of the molten solder flowing in the nozzle path 20 and the gantry path 30 constant, a rod-like cartridge heater is inserted around the nozzle 1 and the nozzle gantry 2 to heat them. When using molten solder as the liquid, the temperature is about 350 ° C., and thus the seal member is required to have heat resistance. In such a case, a carbon packing (carbon seal) may be used as the seal member 8.

  The size of the fine particles to be produced is determined by the diameter of the liquid outlet 22 of the nozzle 1, the outflow speed of the liquid from the liquid outlet 22, and the vibration frequency to be applied. Further, the liquid outflow speed from the liquid outlet 22 can be adjusted by the head difference between the liquid level in the liquid storage tank 3 and the liquid outlet 22. When manufacturing a solder ball with a diameter of 100 μm, the diameter of the liquid outlet 22 of the nozzle 1 is about 53 to 57 μm, and the head difference between the liquid surface in the liquid storage tank 3 and the liquid outlet 22 is 0.3 to 0. It is good to set it as about 4 MPa and to select the frequency of nozzle vibration in the range of 3.0-4.0 kHz.

  When a piezoelectric element is used as the vibration device 4, if the piezoelectric device is a generally used piezoelectric element that vibrates in the thickness direction, the vibration device 4 is configured by stacking 4 to 8 piezoelectric elements in series. Thus, sufficient vibration energy can be applied to the nozzle.

  In the present invention, when the nozzle 1 is vibrated by the vibration device 4, the nozzle base 2 does not vibrate. Accordingly, the gantry path 30 disposed on the nozzle gantry 2 does not vibrate. Only the nozzle 1 vibrates. Therefore, all the vibration energy from the vibration device 4 is transmitted to the nozzle 1 and is fully utilized for droplet generation. As a result, when the microparticles 12 that are droplets are generated using the present invention, droplet size non-uniformity does not occur, and droplets with a sufficiently uniform size can be generated. On the other hand, in the method described in Patent Document 5, a supply line is connected to the vibrating nozzle head, and when the vibrating nozzle head is vibrated, the connected supply line also vibrates. For this reason, the vibration energy from the vibration generator is not fully utilized for droplet generation, and the droplet size is uneven. The same applies when a spiral portion is provided in the supply line.

  In addition, as described in Patent Documents 3 and 4, a method of manufacturing a micro droplet while having a molten metal outflow nozzle at the bottom of a molten metal container filled with molten metal and causing the molten metal to flow out of the nozzle while applying vibration to the molten metal However, the vibration that the molten metal receives at the nozzle outlet is weak, and the power for cutting the jet flowing out from the nozzle is not sufficient, and the vibration power can only play an auxiliary role in cutting the liquid flow. For this reason, the volume of the droplet after cutting is not constant, and a droplet having a uniform particle size cannot be produced. Moreover, since it is necessary to provide a vibration generator on the top part of a molten metal container, it has the fault that the whole height of an apparatus becomes high. On the other hand, in the present invention, the size of the generated droplets can be made sufficiently uniform as described above, and at the same time, it is not necessary to provide a vibration generator on the top of the molten metal container. The thickness can be lowered.

  Solder balls having a diameter of 100 μm were manufactured using the apparatus for manufacturing fine particles of the present invention shown in FIGS. A vibrating device 4 in which six piezoelectric elements are stacked is used. As the nozzle 1, a stainless steel cylindrical nozzle was used. The diameter of the nozzle path 20 in the nozzle 1 is 2 mm. A steel connecting rod 5 was connected between the vibration device 4 and the nozzle 1. Carbon was used as the seal member 8 between the nozzle 1 and the nozzle mount 2. The liquid outlet 22 of the nozzle 1 is made of diamond, the diameter of the liquid outlet 22 is 55 μm, the head difference between the liquid level in the liquid storage tank 3 and the liquid outlet 22 is about 0.4 MPa, The frequency was about 3.5 kHz.

  As a result of manufacturing a solder ball having a standard sphere diameter of 100 μm ± 5 μm using the fine particle manufacturing apparatus of the present invention, the average sphere diameter is 99.7 μm, the maximum sphere diameter is 99.9 μm, and the minimum sphere diameter is 99.3 μm. The standard deviation of the sphere diameter was 0.15 μm, and the variation was 10.05 in Cpk.

  As a comparative example, a solder ball was also manufactured using the apparatus for manufacturing fine particles shown in FIG. A liquid outlet 44 is provided at the bottom of the liquid storage tank 41, a vibration device 42 is disposed above the liquid storage tank 41, and the vibrating rod 43 is immersed in the liquid 11 in the liquid storage tank 41 from the vibration device 42. . By vibrating the vibrating bar 43 by the vibration device 42, the liquid flowing out from the liquid outlet 44 is cut to produce the microparticles 12 that are droplets. As the vibration device 42, four piezoelectric elements stacked one on another were used. The diameter of the liquid outlet 44 was 56 μm, the head difference between the liquid level in the liquid storage tank 41 and the liquid outlet 44 was about 0.1 MPa, and the vibration frequency of the vibrating rod 43 was about 2.0 kHz.

  As a result of manufacturing a solder ball having a standard sphere diameter of 100 μm ± 5 μm using the microparticle manufacturing apparatus of the comparative example, the average sphere diameter is 100.9 μm, the maximum sphere diameter is 102.0 μm, and the minimum sphere diameter is 100.1 μm. The standard deviation of the sphere diameter was 0.49 μm, and the variation was 2.81 in Cpk.

  In the comparative example shown in FIG. 3, since the vibration device 42 is installed on the top of the liquid storage tank 41, the height from the vibration device 42 to the liquid outlet 44 is 500 mm, which is a tall device. On the other hand, in the example of the present invention shown in FIGS. 1 and 2, the height from the top of the liquid storage tank 3 to the liquid outlet 22 can be suppressed to 300 mm, and a compact apparatus can be obtained.

It is sectional drawing which shows an example of the manufacturing apparatus of the microparticles of this invention. It is a figure which shows an example of the manufacturing apparatus of the microparticles of this invention, (a) is whole sectional drawing which shows the condition which manufactures microparticles, (b) is a fragmentary sectional view which shows a nozzle mount, (c) is a nozzle. It is sectional drawing shown. It is a figure which shows the conventional manufacturing apparatus of a microparticle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Nozzle 2 Nozzle mount 3 Liquid storage tank 4 Vibrating device 5 Connecting rod 6 Nozzle holding part 7 Sliding surface 8 Seal member 11 Liquid 12 Fine particle 20 Nozzle path 21 Liquid inlet 22 Liquid outlet 30 Mount path 31 Liquid inlet 32 Liquid outlet 41 Liquid storage tank 42 Vibrating device 43 Vibrating rod 44 Liquid outlet

Claims (6)

  A nozzle for causing the liquid to flow downward; a vibration device for vibrating the nozzle; a nozzle base for slidably holding the nozzle; and a liquid storage tank, wherein the nozzle is connected to a liquid outlet and circulates the liquid. It has a nozzle path, the nozzle gantry has a gantry path that connects the liquid from the liquid storage tank to the nozzle and circulates the liquid, and the nozzle path and the gantry path communicate with each other to allow the liquid to circulate. Grain production equipment.   The apparatus for producing fine particles according to claim 1, further comprising a connecting rod that connects the nozzle and the vibration device.   The end of the nozzle path opposite to the liquid outlet is opened in the sliding surface between the nozzle and the nozzle gantry, and the gantry path is disposed in the nozzle gantry and is opened in the sliding surface between the nozzle and the nozzle gantry. The apparatus for producing fine particles according to claim 1, wherein:   The apparatus for producing fine particles according to any one of claims 1 to 3, wherein the liquid is a molten metal.   Using the apparatus for producing fine particles according to any one of claims 1 to 3, the outflowing liquid is separated into fine particles by causing the liquid to flow out from the liquid outlet of the nozzle while vibrating the nozzle by the vibration device. A method for producing fine particles.   6. The method for producing fine particles according to claim 5, wherein the liquid is a molten metal, and the separated fine particles are solidified to form fine metal spheres.

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