JP2001335816A - Spherical body, manufacturing method and manufacturing apparatus therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a means for easily manufacturing a spherical body such as a solder ball at a low cost with a small number of processes. SOLUTION: The raw material (a) of the spherical body is separated in a predetermined quantity in a molten state, formed into a spherical shape by the surface tension in the molten state, and then, cooled and solidified. Since the raw material is separated in the molten state, a conventional process of working the raw material into plates and wires can be dispensed with, and the manufacturing process can be shortened. In addition, the manufacture is facilitated, and the cost can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to, for example, BGA (b
The present invention relates to a spherical body such as a solder ball used for a bump material of a semiconductor package such as an all grid array or a CSP, and a method and an apparatus for manufacturing such a spherical body.

[0002]

2. Description of the Related Art In the field of, for example, a semiconductor package, a so-called BGA in which solder balls (solder bumps) are mounted instead of leads for making electrical connection to a substrate or the like is known. Conventionally, when manufacturing a solder ball used for such a BGA, the solder processed into a plate material such as a foil or a wire material is precisely cut out or punched in a solid state so that the solder is formed into a desired amount of raw material pieces. After separation, the raw material pieces are heated and melted to form spheres by surface tension, and then cooled and solidified to obtain spherical shaped solder balls. In addition, a solder paste (cream solder) is created, the solder is separated by a certain amount by screen printing or a method of printing it on a board with a fixed volume of holes, etc., and then the solder is heated and melted to make it spherical by surface tension. There is also known a method of causing the same.

[0003]

However, conventionally,
As a pre-process to separate the solder into desired quantities, the solder must be processed into plate material, wire material, solder paste, etc.
It was difficult to shorten the manufacturing process. In addition, in order to accurately measure solder, accurate dimensional accuracy is required for the thickness of the plate material formed in the previous process and the thickness of the wire material, etc., which causes a cost increase in solder ball manufacturing. I was

Accordingly, it is an object of the present invention to provide means for easily and inexpensively manufacturing a spherical body such as a solder ball in a small number of steps.

[0005]

According to the first aspect of the present invention, a spherical material is separated into a fixed amount in a molten state, and a spherical material is formed by a surface tension in a molten state. , And then cooled and solidified to provide a method for producing a spherical body.

As the spherical body manufactured by the manufacturing method of the first aspect, for example, a spherical body such as a solder ball used for a bump material of a semiconductor package such as BGA or CSP is exemplified. Further, as described in claim 7, the material of the spherical body is, for example, a metal, and as an example, solder (for example, Sn-Pb eutectic solder) is exemplified. In addition to solder,
The raw material of the spherical body may be a single metal or an alloy composed of two or more metals whose liquidus temperature is 450 ° C. or less (may be 450 ° C. or more) as described in claim 8. It may be. Furthermore, it is also possible to use materials other than metals as raw materials for the spherical body.

According to the manufacturing method of the first aspect, since the raw material of the spherical body is separated into a fixed amount in a molten state, the step of processing the raw material such as solder into a plate or wire as in the conventional method is unnecessary. Thus, the manufacturing process can be shortened.
Further, since it is not necessary to process the raw material into a plate or a wire that requires accurate dimensional accuracy or the like, manufacturing becomes easy and cost reduction can be realized.

As described in the second aspect, the raw material of the spherical body is flowed into the tube in a molten state, and when a certain amount of the raw material flows, the melt is separated from the tube. In this case, the flow of the melt may be continuous or intermittent. In order to separate the melt from the tube, the melt may be dropped by its own weight when the melt reaches a certain amount, for example, at the tip of the tube. Further, as described in the third aspect, the nozzle for discharging the melt may be reciprocated in the horizontal direction, and the melt may be separated from the nozzle by the reciprocating vibration. In the case where the nozzle is reciprocated in the horizontal direction, the melt can be shaken off from the tip of the nozzle by the vibration. Therefore, the raw material of the spherical body is continuously melted at a constant flow rate from the nozzle in the state of the melt. It may be ejected selectively. In this case, for example, as described in claim 4, it is possible to drop the melt from the tip of the nozzle at the moving end of the reciprocating vibration. As described in claim 5, it is preferable that the movement of the nozzle on the outward path of the reciprocating vibration and the movement of the nozzle on the return path are symmetric. If the vibration of the nozzle is symmetric, the amount of melt dropped from the tip of the nozzle at the moving end where the movement of the nozzle has been completed in the forward path and the amount of melt dropped from the tip of the nozzle at the moving end where the movement of the nozzle has been completed in the return path The amount of the melt is equalized, and the melt can be dropped at regular intervals. The reciprocating vibration is, for example, a simple vibration. If the nozzle is caused to vibrate in the horizontal direction, a maximum acceleration is applied to the melt discharged from the nozzle at the moving end of the reciprocating vibration, whereby the melt is shaken off from the nozzle at the moving end of the reciprocating vibration. To be dropped.

Further, as described in claim 7, it is preferable that the raw material of the sphere is formed into a sphere in the air or liquid which does not react with the raw material of the sphere and cooled. By doing so, it is possible to mold, cool, and solidify the raw material of the spherical body without deteriorating the quality, and to manufacture a spherical body of excellent quality. In this case, for example, as described in claim 10, the raw material of the spherical body separated into a certain amount in the state of the melt is heated to a high temperature above the melting point of the raw material of the spherical body, It is dropped by its own weight in a molten state in a liquid in which a temperature gradient is formed so as to be a low temperature below the melting point of the raw material, and it is made spherical by surface tension in the upper part of the liquid and then in the lower part of the liquid It is possible to cool and solidify. Also as described in claim 11, the raw material of the spherical body is a metal, a liquid where the liquid has a liquidus temperature T _L above the boiling point T _B metals, to a temperature less than T _L or T _B After the spherical raw material is made into a spherical shape by surface tension in a molten state in the liquid thus obtained, it is preferable to cool and solidify the spherical raw material in the liquid at a temperature _lower than _TL . in this case,
For example, if the material of the spherical body is solder, the liquid is exemplified by vegetable oil.

According to a twelfth aspect of the present invention, there is provided a nozzle for dropping a spherical raw material in a molten state, and a molding unit for making the spherical raw material dropped from the nozzle into a spherical shape by surface tension in a molten state. And a cooling unit for cooling and solidifying the spherical body.

In the manufacturing apparatus according to the twelfth aspect, the raw material of the spherical body dropped from the nozzle is first deformed into a spherical shape by the surface tension in a molten state in the molding section.
Thereafter, the raw material of the spherical body is cooled and solidified in the cooling section. Thus, a spherical body is manufactured.

In the manufacturing apparatus according to the twelfth aspect, as described in the thirteenth aspect, a driving mechanism for reciprocating the nozzle in a horizontal direction may be provided. As described in claim 14, it is preferable that the discharge port formed at the tip of the nozzle has a circular cross-section arranged horizontally.

According to claim 15, the following equation (1) and
And a spherical body satisfying the expression (2). 50 pieces
For each spherical body, the major axis D_LAnd minor axis D_SMeasure
And the average value DM = (D_L+ D_S) / 2 is D
_M1, D_M2, D_M3… D_M50As these D_M1
~ D_M50The maximum value of D_ML, The minimum value is D_MSAnd true
Sphericity A = 1- (D_L-D_S) / D_MTo A₁, A
₂, A₃... A₅₀As these A ₁~ A₅₀The most
Small value is A_MinThen, (D_ML-D_MS) / (D_ML+ D_MS) <0.02 (1) Expression A_Min> 0.9 ... (2)

According to the fifteenth aspect of the present invention, there is provided the spherical body.
The manufacturing method of the present invention is suitably performed by the manufacturing method of the present invention.

[0015]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an explanatory view of an apparatus 1 for producing a spherical body according to an embodiment of the present invention. In this embodiment, BGA or CSP is used as an example of a spherical body.
A manufacturing apparatus 1 for manufacturing a solder ball used for a bump material of a semiconductor package such as a semiconductor package will be described.

A band heater 11 is mounted around the raw material melting section 10, and the heating of the band heater 11 causes the solder ingot put into the furnace section 12 in the raw material melting section 10 to melt the melting point of the solder (for example, 183). (゜ C) or higher (for example, 220 to 240 ° C) to be melted. The raw material melting section 10 is, for example, SU
S304 and the like are configured so as not to be melted even if heated to a temperature higher than the melting point of the solder. The heating temperature of the furnace section 12 in the raw material melting section 10 is detected by a thermocouple 13 and controlled so that the temperature in the furnace section 12 is equal to or higher than the melting point of solder (for example, 220 to 240 ° C.). .

The raw material melting section 10 is filled in a cylinder 15.
Nitrogen gas (N ₂) Put the air supply pipe 16
And the nitrogen gas is supplied into the furnace section 12.
(In the drawing, the upper part of the raw material melting section 10 is supplied).
Although the trachea 16 is depicted as connected,
The connection position of the pipe 16 can be arbitrarily changed.
An air supply pipe 16 may be connected to the lower part of the apparatus 10). This
And the oxidation of the solder that has been put into the furnace 12 and melted, etc.
Has been prevented. A liquid feed pipe 17 is provided below the raw material melting section 10.
Is connected, and is charged into the furnace section 12 to become a melt.
The solder is drained downward through the liquid supply pipe 17.
ing. In this case, through the air supply pipe 16,
By injecting nitrogen gas, the melt
It is also possible to forcibly push the lost solder to the liquid supply pipe 17 side
Noh. In addition, the liquid supply pipe 17 is supplied with the molten solder.
A needle valve 18 for adjusting the liquid volume is provided.
I have.

A tubular nozzle 21 is connected to the lower end of the liquid supply pipe 17 via a flexible hose 20, and the molten solder in the furnace 12 is supplied to the liquid supply pipe 17 and the flexible hose 20. And the liquid is sent through the nozzle 21,
The liquid is discharged downward from a discharge port 22 formed at the tip (lower end) of the nozzle 21. By operating the needle valve 18 described above, the discharge of the solder from the discharge port 22 can be stopped or the discharge amount can be adjusted. The nozzle 21 is movably attached to the liquid feed pipe 17 fixed below the raw material melting section 10 by being connected via the flexible hose 20.
These tubes 17, flexible hose 20 and nozzle 21
Is equipped with a band heater 23 around the tube 1
7. By detecting the solder fed into the flexible hose 20 and the nozzle 21 by the thermocouple 24 and controlling the temperature to a temperature higher than the melting point (for example, 220 to 240 ° C.) by heating the band heater 23, The state of the melt is maintained. These tubes 17,
Each of the flexible hose 20 and the nozzle 21 is made of, for example, SUS304 or the like, and is not melted even when heated to a temperature higher than the melting point of solder. In this embodiment, the nozzle 21 is formed of a hollow circular tube.
Is cut into an orthogonal plane, so that the discharge port 22 at the tip of the nozzle 21 has a circular cross-section that is horizontally arranged. The inner diameter of the discharge port 22 at the tip of the nozzle 21 is set to, for example, 0.25φ.

A driving mechanism 25 for reciprocating the nozzle 21 in the horizontal direction is provided. That is, one end of a rod 27 is vertically attached to the nozzle 21 via a block 26. The rod 27 is slidably supported in a horizontal direction by a guide 28, and the other end of the rod 27 is urged to always contact the peripheral surface of the cam 29. The rotation power of the motor 30 is transmitted to the cam 29, and the rotation of the cam 29 by the operation of the motor 30 causes the rod 27, the other end of which is always in contact with the peripheral surface of the cam 29, to pass through the guide 28. It is designed to reciprocate. With the reciprocating movement of the rod 27, the nozzle 21 attached to one end of the rod 27 via the block 26 reciprocates in the horizontal direction.

The tip of the nozzle 21 is placed in a container 35. As shown in FIG. 2, the container 35 is filled with a liquid 36 that does not react with solder, such as vegetable oil, and a discharge port 22 formed at the tip of a nozzle 21 placed in the container 35 is filled with a liquid. 36 is immersed in the liquid surface. As a result, as described above, the solder (a melted solder) a discharged from the discharge port 22 at the tip of the nozzle 21 is directly discharged into the liquid 36, and then, in the container 35, by its own weight in the container 35. It is falling.

The upper part of the liquid 36 filled in the container 35 is a molding part 37 and the lower part is a cooling part 3.
It is eight. A plurality of band heaters 40 are mounted on the peripheral surface of the container 35 in multiple stages, and the heating temperature of each of the band heaters 40 can be controlled independently. By changing the heating temperature of each band heater 40, , It is possible to form a temperature gradient in the liquid 36 in the container 35. The heating temperature of each band heater 40 is set to be higher as it goes upward, so that the container 35
In the upper and lower molded portions 37, the heating temperature of the band heater 40 is high, and the temperature of the liquid 36 detected by the thermocouple 41 is set to a temperature equal to or higher than the melting point of the solder a (for example, 190).
゜ 200 ° C.). On the other hand, in the cooling section 38 in the lower part of the container 35, the heating temperature of the band heater 40 is low, and the temperature of the liquid 36 detected by the thermocouple 42 is lower than the melting point of the solder a (for example, 20 to 40 ° C.). C). Thus, container 3
The liquid 36 filled in 5 has a gentle temperature gradient such that the upper part has a high temperature equal to or higher than the melting point of the solder a and the lower part has a low temperature equal to or lower than the melting point of the solder a.

A lid 45 is attached to the upper surface of the container 35, and the discharge port 22 at the tip of the nozzle 21 is immersed in the liquid 36 in the container 35 through a slit 46 formed in the lid 45. The slit 46 has a horizontally long shape so as to receive the reciprocating vibration of the nozzle 21 in the horizontal direction described above. In addition, an inert gas such as N ₂ gas is supplied from an air supply pipe 47 to an upper space (a space above the liquid surface of the liquid 36) surrounded by the lid 45. Maintained in an inert atmosphere. Further, a shower nozzle 48 for reducing oxygen in the liquid 36 by bubbling an inert gas into the liquid 36 is disposed at the bottom of the container 35.
Further, a concentration meter 49 for sampling the atmosphere above the liquid level in the container 35 and detecting the oxygen concentration is also provided.

When the motor 30 operates in the drive mechanism 25 described above, the nozzle 21 is moved around the neutral position indicated by the origin (coordinate 0) of the X axis (horizontal axis) in FIG. Of one moving end indicated by L, and X
It reciprocates linearly and reciprocally in the horizontal direction with an amplitude L (for example, 3.8 mm) between the axis and the other moving end indicated by -L. Note that the neutral position (origin) at which the reciprocating vibration is stopped is set so as to coincide with the central axis of the container 35.

FIG. 4 is a graph showing the relationship between the displacement X from the origin of the nozzle 21 and the time T. The relationship between the displacement X and the time T is represented by a sine curve (or cosine curve). (X = Lsin (ωT + θ)).
That is, as shown in FIG. 4, in the manufacturing apparatus 1 of the illustrated embodiment, the nozzle 21
In a state where the discharge port 22 at the tip of the nozzle 21 is immersed in the container 6, a single vibration (for example, a frequency of 23 Hz) having an amplitude L is performed in the horizontal direction about the central axis of the container 35.

Now, in the manufacturing apparatus 1 of the embodiment of the present invention configured as described above, the solder ingot (for example, Sn-Pb eutectic solder) is placed in the furnace section 12 in the raw material melting section 10.
And the solder ingot is melted by the band heater 11 in an inert atmosphere in which nitrogen gas is supplied into the furnace section 12 through the air supply pipe 16 (for example, at a temperature of 183 ° C.).
The temperature is raised to the above temperature (for example, 220 to 240 ° C.) to be melted. Until the temperature of the solder becomes stable, the discharge of the solder from the discharge port 22 is stopped by operating the needle valve 18. The solder a thus melted is sent through the liquid sending pipe 17, the flexible hose 20, and the nozzle 21, and is discharged downward from the discharge port 22 at the tip of the nozzle 21. In this case, by operating the needle valve 18, the discharge amount of the solder can be adjusted. Further, by injecting nitrogen gas into the furnace section 12 through the air supply pipe 16, it is possible to forcibly extrude the solder a which has become a melt in the furnace section 12 toward the liquid feed pipe 17. In the example shown in the figure, the opening degree of the needle valve 18 is fixed, and the nitrogen gas pressure injected into the furnace section 12 through the air supply pipe 16 is kept constant, so that the solder a (melt) in the liquid feed pipe 17 is formed. The flow rate is kept constant, and the discharge amount from the discharge port 22 at the tip of the nozzle 21 is made constant.

While the molten solder a is discharged from the discharge port 22 at the tip of the nozzle 21 at a constant flow rate,
The motor 30 operates in the drive mechanism 25 described above. With this, the nozzle 21 has the amplitude L in the horizontal direction while the center axis of the container 35 is set to the neutral position in a state where the discharge port 22 at the tip of the nozzle 21 is immersed in the liquid 36 in the container 35.
The simple vibration of is performed. As described above, while the solder a in a molten state is discharged downward from the discharge port 22 at the tip of the nozzle 21 and the nozzle 21 is reciprocated in the horizontal direction, the solder a discharged from the discharge port 22 is vibrated. By nozzle 2
1 It is shaken off from the tip and dripped, and falls in the liquid 36 filled in the container 35 by its own weight.

Here, as described above, when the nozzle 21 performs a simple vibration (for example, an amplitude of 3.8 mm and a frequency of 23 Hz), the reciprocating vibration of the solder a in the molten state discharged from the nozzle 21 is performed. The maximum acceleration will be applied at the moving end of. As a result, the nozzle 21 at the moving end of the reciprocating vibration where the force acting on the solder a in the horizontal direction is maximized.
The solder a in the molten state is shaken off from the tip and dropped. As shown in FIG. 2, the solder a dropped from the tip of the nozzle 21 is distributed to both sides of the reciprocating vibration moving direction (left and right in FIG. Will fall under its own weight. In the case of simple vibration, the nozzle 2
1 and the movement of the nozzle 21 in the return path are symmetrical, and the amount of solder a (melt) accumulated at the tip of the nozzle 21 during movement on the outward path and the solder a (melt) accumulated at the tip of the nozzle 21 during movement on the return path Are equal. Therefore, the amount of solder a (melt) dropped from the tip of the nozzle 21 at the moving end where the forward movement has been completed, and the amount of solder a (melt) dropped from the tip of the nozzle 21 at the moving end having completed the return movement. Liquid) are equal. For this reason, the solder a (melt) can be constantly dropped at a fixed amount at the moving end of the reciprocating vibration in the container 35.

In this way, the solder a dropped from the tip of the nozzle 21 and falling in the liquid 36 first passes through the molded portion 37 formed in the upper half of the liquid 36 and then formed in the lower half. It passes through the cooling unit 38. The heating of the band heater 40 causes the temperature of the liquid 36 to be equal to or higher than the melting point of the solder a in the molding portion 37 (for example, 190 to 200 ° C.).
While the molded part 37 is falling, the solder a is maintained in a molten state, and is deformed into a spherical shape by its surface tension. Then, the solder a thus deformed into a sphere then falls down the cooling part 38. In the cooling part 38, the heating temperature of the band heater 40 is low, and the temperature of the liquid 36 is lower than the melting point of the solder a. Since the temperature is (for example, 20 to 40 ° C.), the solder a is cooled and solidified while falling down the cooling section 38. In this way, the solder a (solder ball) which has become a spherical body is manufactured and accumulated at the bottom of the container 35. As described above, the liquid 36 filled in the container 35 has a high temperature above the melting point of the solder a and a low temperature below the melting point of the solder a by the heating control of each band heater 40. As described above, since the temperature is formed to have a gentle temperature gradient, the solder a falling from the molding portion 37 to the cooling portion 38 does not receive a sudden temperature change, and a shape defect or the like due to a sudden change in temperature occurs. Disappears.

According to the above-described embodiment of the present invention, the melt of the solder a can be separated by a predetermined amount by the vibration of the nozzle 21, so that the raw material is processed into a plate or a wire as in the related art. This eliminates the need for a process, and shortens the manufacturing process of the solder ball. Further, since it is not necessary to process the raw material into a plate or a wire that requires accurate dimensional accuracy or the like, solder balls can be easily manufactured and cost reduction can be realized. The amount of the solder a dropped at the tip of the nozzle 21 is, for example, the amount of the solder discharged from the nozzle 21, the cycle of the reciprocating vibration (simple vibration) of the nozzle 21 (2π / ω),
It can be adjusted by changing the amplitude L, etc.
Accordingly, the size of the solder ball manufactured can be adjusted.

When the solder a is dropped from the tip of the nozzle 21 into the liquid 36 in the container 35,
An inert gas (for example, a nitrogen gas having an oxygen concentration of 1 ppm or less) is supplied from a shower nozzle 48 provided at the bottom to the liquid 3.
It is preferable that oxygen in the liquid 36 be reduced in advance by bubbling in the liquid 6. In addition,
When bubbling the inert gas from the shower nozzle 48 in such a manner, a minimum hole for letting the bubbled inert gas escape to the outside is provided instead of the lid 45 having the slit 46 as shown in FIG. If a lid (not shown) without the formed slit is used, it is possible to reduce oxygen in the liquid 36 in an atmosphere environment which is shielded from the outside air. When the solder ball is manufactured in a state where oxygen is entrapped in the liquid 36 without bubbling the inert gas,
The oxygen concentration in the liquid 36 is on the order of several percent, and the solder a in the molten state is oxidized and the spheroidization is hindered. However, if the oxygen concentration is reduced by bubbling the inert gas into the liquid 36 from the shower nozzle 48 in advance, the spheroidization is not hindered, and a solder ball having a shape close to a true sphere can be manufactured. In this case, the oxygen concentration in the liquid 36 is reduced to 0.1% or less by using a lid (not shown) having no slit, and then the slit 4 is removed.
It is recommended to replace the cover 45 with the cover 6.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment. FIG. 5 shows a nozzle 50 according to another embodiment of the present invention. On the lower surface 51 of the nozzle 50, a number of discharge ports 52 are formed. Upper surface 5 of nozzle 50
Numeral 3 is movable, and the upper surface 53 is pressed inward of the nozzle 50 by the pressure applied via the pusher 54. The inside of the nozzle 50 is filled with the solder a heated to a temperature higher than the melting point and brought into a molten state. When the upper surface 53 is pressed, the solder a inside the nozzle 50 drops from each of the discharge ports 52. Although not shown, the solder melted in the raw material melting section is in a molten state inside the nozzle 50 of the embodiment shown in FIG. 4 in the same manner as the embodiment described above with reference to FIG. It is being supplied. Nozzle 5
The solder a dropped from each of the discharge ports 52 formed on the lower surface 51 of the liquid 0 falls under its own weight in the liquid 36 as in the case described above with reference to FIG. After being deformed, it is cooled and solidified in the cooling section 38. If the nozzle 50 of the embodiment described with reference to FIG. 5 is used, more solder balls can be manufactured in a short time by dropping the solder a from the large number of discharge ports 52.

In the above embodiment, an example of manufacturing a solder ball as an example of a spherical body has been described. However, the raw material of the spherical body may be a metal other than solder or a material other than metal. The liquid 36 is not limited to vegetable oil and may be another liquid or gas. Further, the movement of the nozzle 21 is not limited to the reciprocating vibration, and the melt may be shaken off by another vibration movement (for example, a vibration movement that moves the nozzle 21 in an equilateral triangle). Further, it is also possible to drop the melt from the nozzle 21 by fixing the nozzle 21 and discharging the melt intermittently. Furthermore, the melt may be separated by a predetermined amount by dropping the melt by its own weight from the fixed nozzle 21.

[0033]

EXAMPLE Solder balls were manufactured by actually using the manufacturing apparatus 1 according to the embodiment of the present invention described with reference to FIG. Nozzle 2
1 uses a SUS316 pipe with an inner diameter of 0.25φ, and discharges the discharge port 22 at the tip of the nozzle 21 into a liquid 36 (soybean oil) for about 2 hours.
３3 mm. Furnace section 1 in raw material melting section 10
2 (inner size 25φ × 100 ^H ) with Sn-Pb eutectic solder
After setting 0 g, the furnace section 12 was purged with nitrogen to suppress oxidation, and then heated by the band heater 11 to melt the solder. The heating temperature in the raw material melting section 10 is 220 to 24
The temperature of the pipe 17, the flexible hose 20, and the nozzle 21 was also controlled to a temperature equal to or higher than the melting point of the solder (220 to 240 ° C. in the embodiment) by heating the band heater 23. Then, nitrogen gas was leaked into the furnace section 12 through the air supply pipe 16, and the molten solder was discharged from the discharge port 22 at the tip of the nozzle 21.

Thereafter, the drive mechanism 25 was operated, the nozzle 21 was oscillated in a simple manner at a frequency of 23 Hz and an amplitude of 3.79 mm, and the solder melt was dropped into the liquid 36 (soybean oil) from the tip of the nozzle 21. In the molding section 37, 1 soybean oil
The temperature was set to 90 to 200 ° C., and the cooling unit 38 was set to 20 to 40 ° C.

FIG. 6 shows a droplet from the tip of the nozzle 21 into soybean oil.
It is a drawing showing a dropped state of solder a dropped. This figure 6
As shown in the figure, the solder a is reciprocated by the nozzle 21
It was distributed right and left and dripped. FIG.
Enlarged view of a solder ball manufactured according to the embodiment of the present invention.
(SEM image sketch). Manufactured in an embodiment of the present invention
Major diameter D for 50 solder balls_LAnd minor axis D_STo
Measure the average diameter and sphericity of each solder ball
Was. Here, the average diameter is (D_L+ D_S) / 2, sphericity A is
It is not three-dimensional, but A = (1- (D_L-D_S) /
((D_L+ D_S) / 2)) × 100 (%).
As a result, the average value of the average diameter was 763 (μm), and the minimum value D was
_MSIs 751 (μm), the maximum value D_MLIs 772 (μm)
And the sphericity (%) is 98.3 (average), 97.6
(Minimum A_Min), 100.0 (maximum A _Max) And
This is a general standard for solder balls for bump materials.
760 ± 20μm diameter accuracy and 95% or more sphericity
Was. In addition, a half manufactured according to the embodiment of the present invention.
Taba ball satisfies the following equations (1) and (2)
Was. (D_ML-D_MS) / (D_ML+ D_MS) <0.02 (1) Expression A_Min> 90% ... Formula (2)

The liquid 36 is manufactured in the same manner as described above.
When adjusting the oxygen in (soybean oil), when the production of solder balls is started at the time when the oxygen concentration in the sampling gas has decreased to only 0.5%, the average diameter (μm) of the obtained solder balls is as follows. 765 (average), 748 (minimum), 7
The sphericity (%) was 94.2 (average), 89.8 (minimum), and 97.2 (maximum), and the variation in the diameter was large and the sphericity was reduced.

[0037]

According to the first to fifteenth aspects, since the raw material of the spherical body is separated in a molten state, a desired amount of the raw material can be easily separated with high precision. Preliminary steps for processing such raw materials into plate and wire materials are not required, and the manufacturing process can be shortened. Also, since it is not necessary to process the raw material into a plate or a wire that requires accurate dimensional accuracy or the like, the production becomes easy and the cost can be greatly reduced. In addition, the raw material of the spheroid can be molded, cooled and solidified without deteriorating, so that a sphere with excellent quality can be manufactured, and a washing step can be omitted.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an apparatus for manufacturing a spherical body according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a molding section and a cooling section.

FIG. 3 is an explanatory diagram of reciprocating vibration of a nozzle.

FIG. 4 is a graph showing a relationship between displacement from the origin of the nozzle and time.

FIG. 5 is an enlarged sectional view of a nozzle according to another embodiment of the present invention.

FIG. 6 is a view showing a state in which solder dropped from a nozzle tip falls.

FIG. 7 is an enlarged view of a solder ball manufactured according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Manufacturing apparatus 10 Raw material melting part 11,23,40 Band heater 12 Furnace part 13,24,41,42 Thermocouple 15 Bomb 16 Gas supply pipe 17 Liquid feed pipe 18 Needle valve 20 Flexible hose 21 Nozzle 22 Discharge port 25 Drive mechanism 28 Guide 29 Cam 30 Motor 35 Container 36 Liquid 37 Molding part 38 Cooling part 45 Lid 46 Slit 47 Air supply pipe 48 Shower nozzle 49 Densitometer

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Takashi Ono, Inventor 1-8-2 Marunouchi, Chiyoda-ku, Tokyo Dowa Mining Co., Ltd. (72) Keigo Kikuchi Inventor 1-8-2 Marunouchi, Chiyoda-ku, Tokyo Same as above F Mining in WA Mining Co., Ltd. (Reference) 4K017 AA04 BA01 BB01 CA01 DA09 EC01 FA05 FA22

Claims (15)

[Claims] 1. A method for separating a spherical raw material into a predetermined amount in a molten state, forming a spherical shape by surface tension in a molten state, and then cooling and solidifying the raw material. Production method. 2. A raw material for a sphere is flowed in a molten state through a tube.
2. The method for producing a spherical body according to claim 1, wherein the melt is separated from the tube when a predetermined amount of the melt flows. 3. The method for producing a spherical body according to claim 1, wherein the nozzle for discharging the melt is reciprocated in a horizontal direction, and the melt is separated from the nozzle by the reciprocating vibration. 4. The method according to claim 3, wherein a melt is dropped from a nozzle at a moving end of the reciprocating vibration. 5. The method for manufacturing a spherical body according to claim 3, wherein the movement of the nozzle on the outward path and the movement of the nozzle on the return path of the reciprocating vibration are symmetrical. 6. The method for producing a spherical body according to claim 3, wherein said reciprocating vibration is a simple vibration. 7. The method according to claim 1, wherein the raw material of the sphere is formed into a sphere in the air or liquid that does not react with the raw material of the sphere and cooled. A method for producing any spherical body. 8. The method for producing a spherical body according to claim 1, wherein the raw material of the spherical body is a metal. 9. The raw material for a sphere is a liquid having a liquidus temperature of 4 ° C.
9. The method for producing a spherical body according to claim 8, wherein the metal body is a single metal having a temperature of 50 ° C. or less or an alloy of two or more metals. 10. A raw material of a spherical body separated into a certain amount in a molten state is heated to a high temperature above the melting point of the raw material of the spherical body and to a low temperature below the melting point of the raw material of the spherical body. It is characterized by falling under its own weight in a molten state in a liquid in which a temperature gradient is formed, forming a spherical shape by surface tension in the upper part of the liquid, and then cooling and solidifying it in the lower part of the liquid. Claims 1, 2, 3, 4,
A method for producing any one of 5, 6, 7, 8 and 9 spherical bodies. Raw material 11. spheres is a metal, a liquid where the liquid has a liquidus temperature T _L above the boiling point T _B of the metal, in a liquid which is a temperature lower than T _L or T _B After the spherical raw material is made into a spherical shape by surface tension in the molten state,
The method for producing a spherical body according to claim 10, wherein the raw material for the spherical body is cooled and solidified in a liquid at a temperature _lower than _TL . 12. A nozzle for dropping a raw material of a spherical body in a molten state, a molding part for making a raw material of a spherical body dropped from the nozzle into a spherical state by a surface tension in a molten state, and cooling and solidifying. An apparatus for manufacturing a spherical body, comprising: a cooling unit for causing the spherical body to be manufactured. 13. An apparatus for manufacturing a spherical body, comprising a driving mechanism for reciprocating the nozzle in a horizontal direction. 14. The apparatus for manufacturing a spherical body according to claim 12, wherein a discharge port formed at a tip of the nozzle has a circular cross-section arranged horizontally. 15. A spherical body satisfying the following expressions (1) and (2). About 50 spheroids were measured major axis _{D L} to the minor axis _{D S,} respectively, the mean value DM = _(D L +
D _S) / 2, _{respectively, D M1, D M2, D} M3 ... D
_{As M50} , the maximum value of these D _{M1 to} D _M50 is D
_ML, the minimum value and _{D MS,} sphericity A = (1- _{(D L} -
_{D S) / D M) ×} 100 (percent), respectively _{A 1, A} 2,
As _{A 3} ... A _{5 0,} if the minimum value of these _A 1 _{to A 50} and _{A Min, (D ML -D MS} ) / (D ML + D MS) <0.02 ... (1) Equation A _Min> 90% ... Formula (2)