Device for preparing uniform solder balls by adopting shredding and remelting method and production method of uniform solder balls

Abstract

The invention discloses a device for preparing uniform solder balls by adopting a shredding and remelting method and a production method thereof, based on the shredding and remelting method, a welding wire is cut into sections by utilizing a shredding device according to a certain frequency, the welding wire sections penetrate through a preheating system under the action of gravity, and after being fully melted in the preheating system, the welding wire sections fall into a spheroidizing device containing a spheroidizing medium, and the spheroidizing device is used for spheroidizing the uniform solder balls. Under the action of the heating system, the welding wire section is spheroidized in the spheroidizing medium under the combined action of surface tension, buoyancy, viscous resistance and gravity, and then the welding wire section is quickly condensed through the cooling system to prepare the welding ball, so that the high efficiency and the reliability of preparing the welding ball through shredding and remelting are enhanced, and the quality of a welding ball product is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of the preparation of solder balls for microelectronic packaging, and particularly relates to a device for preparing uniform solder balls by a wire cutting and remelting method and a production method thereof. Background Art

[0002] In addition to important applications in advanced electronic packaging technology, uniform solder balls also have strong application prospects in many industries (such as camera modules, VCM modules, contact brackets, magnetic heads and other precision micro-components and micro-motors). With the rapid progress of technology, the application market of solder balls has been further broadened. However, the solder ball preparation technology developed relying on advanced electronic packaging technology is difficult to meet the requirements of multiple industries for the size of tin balls. The size of solder balls required in fields such as special contact brackets and micro-motors is between 1.0 - 1.8 mm, and the demand is gradually increasing.

[0003] Currently, the solder ball preparation industry at home and abroad can prepare uniform solder balls suitable for advanced packaging technology by the jet perturbation method, and the solder ball diameter is maintained between 0.2 mm and 1.0 mm. When preparing larger solder balls above 1.0 mm, because the selected nozzle will be relatively large, the solder will flow out of the nozzle quickly under the action of its own gravity, and it is difficult to match the applied perturbation frequency with the flow rate, so the preparation is relatively difficult. Therefore, developing excellent tin ball preparation technology above 1.0 mm has important value and significance for further improving electronic packaging technology and promoting the development of science and technology. Summary of the Invention

[0004] The purpose of the present invention is to provide a device for preparing uniform solder balls by a wire cutting and remelting method and a production method thereof, which are used to prepare large-sized solder balls to meet the requirements of various industries for large-sized solder balls.

[0005] To solve the above technical problems, the present invention adopts the following technical scheme: A device for preparing uniform solder balls by a wire cutting and remelting method includes a wire cutting device and a spheroidizing device. The spheroidizing device includes a spheroidizing cavity, a flared opening arranged at the top of the spheroidizing cavity, and a steel frame.

[0006] The spheroidizing cavity is used to store the spheroidizing medium and is made of a material that can withstand high temperatures of 800 °C. It is divided into a preheating part, a heating part, and a cooling part. The height of the preheating part is at least 0.4 m, the height of the heating part is at least 0.7 m, and the height of the cooling part is at least 0.5 m.

[0007] The flared opening prevents the welding wire from falling outside the spheroidizing cavity.

[0008] The steel frame ensures that the spheroidizing cavity remains in a vertical state, avoiding the influence of the inclination of the spheroidizing cavity on the preparation of solder balls caused by the welding wire falling and hanging on the wall.

[0009] Furthermore, at the upper part of the spheroidizing chamber is a preheating system for the preheating section, with a first heating jacket and a hole for connecting a gas guide pipe arranged successively from top to bottom on the outside; the middle part is a liquid control system, with a first liquid guide pipe and a second liquid guide pipe arranged on both sides respectively; the upper part of its lower part is a heating system for the heating section, with a second heating jacket arranged on the outside and a hole in the middle for arranging a temperature measuring probe; the lower part of its lower part is a cooling system for the cooling section, with a cooling chamber arranged on the outside; a collecting vessel serving as a collecting system is arranged below it; a wire cutting device is arranged above the bell mouth, and the center of the bell mouth is aligned with the lower end of the slope of the wire cutting device.

[0010] Furthermore, the preheating system of the spheroidizing device includes a first heating jacket, a temperature control box connected to the first heating jacket by a first wire, a gas guide pipe, and a nitrogen generator connected to the spheroidizing chamber through the gas guide pipe;

[0011] The first heating jacket is used to heat the internal space of the upper part of the spheroidizing chamber, contains a thermocouple to measure the temperature of the heating jacket, and has a heat insulation layer on the outside;

[0012] The first temperature control box is used to control the temperature of the first heating jacket, with an adjustable temperature range of 0 - 600 °C and a preheating temperature of over 400 °C;

[0013] The gas guide pipe is used to guide nitrogen into the spheroidizing chamber and is made of high-temperature resistant material;

[0014] The nitrogen generator uses pressure swing adsorption technology to produce high-purity nitrogen and reduce the oxygen content in the internal space of the upper part of the spheroidizing chamber.

[0015] Furthermore, the liquid control system in the spheroidizing device includes a first liquid guide pipe, a first ball valve arranged at the top of the first liquid guide pipe, a pump arranged in the middle of the first liquid guide pipe, a first liquid storage container connected together at the bottom of the first liquid guide pipe, a second liquid guide pipe, and a second liquid storage container connected together at the bottom of the second liquid guide pipe;

[0016] The first liquid guide pipe and the second liquid guide pipe can respectively guide the spheroidizing medium to flow into and out of the spheroidizing chamber and are made of high-temperature resistant material;

[0017] The first liquid storage container and the second liquid storage container are used to store the spheroidizing medium;

[0018] The pump is used to pump out the spheroidizing medium in the first liquid storage container and flow it into the spheroidizing chamber;

[0019] The first ball valve is mainly used to prevent the spheroidizing medium in the spheroidizing chamber from flowing back into the first liquid storage container.

[0020] Further, the heating system in the spheroidizing device includes a second heating jacket, a second temperature control box connected to the second heating jacket by a second wire, a temperature measuring probe connected to the spheroidizing cavity, and a temperature display connected to the temperature measuring probe;

[0021] The second heating jacket is used to heat the spheroidizing medium in the spheroidizing cavity, contains a thermocouple to measure the temperature of the heating jacket, and has a heat insulation layer outside;

[0022] The second temperature control box is used to control the temperature of the second heating jacket, and the adjustable temperature range is 0 - 400 °C;

[0023] The temperature measuring probe is used to measure the temperature of the spheroidizing medium in the spheroidizing cavity, and the temperature measuring range is -50 - 500 °C;

[0024] The temperature display shows the temperature measured by the temperature measuring probe.

[0025] Further, the cooling system in the spheroidizing device includes a cooling bin, a third liquid guide pipe, and a condenser connected to the cooling bin through the third liquid guide pipe;

[0026] There is cold water in the cooling bin to reduce the temperature of the spheroidizing medium in the spheroidizing cavity;

[0027] The condenser is provided with a water inlet, water can be added, the water temperature is cooled by the condenser, and circulating cold water is provided for the cooling bin through the third liquid guide pipe, and the adjustable temperature range is -30 - 30 °C.

[0028] The collection system in the spheroidizing device includes a collection container, a third ball valve arranged above the collection container, and a second ball valve arranged above the third ball valve;

[0029] The collection container collects part of the falling spheroidizing medium and all the welding balls;

[0030] The second ball valve and the third ball valve are used to control the falling of the spheroidizing medium and the welding balls;

[0031] The third ball valve, as the second ball valve of the collection system, is used in cooperation with the second ball valve to prevent all the spheroidizing medium in the spheroidizing cavity from falling, playing a role in saving resources.

[0032] Further, the wire cutting device prepares wire segments with a length of more than 0.5 mm.

[0033] Further, the diameter of the prepared uniform welding balls is more than 1.0 mm.

[0034] The production method using the device for preparing uniform welding balls by the wire cutting and remelting method includes the following steps:

[0035] Step 1, create a spheroidizing space

[0036] Open the first ball valve at the top of the first liquid guide pipe to keep the inside of the first liquid guide pipe unobstructed. Use the pump in the middle of the first liquid guide pipe to introduce the spheroidizing medium in the first liquid storage container into the spheroidizing chamber. When the spheroidizing medium flows from the spheroidizing chamber to the liquid storage container through the second liquid guide pipe, it indicates that the specified spheroidizing interval height has been reached. Close the pump and the first ball valve. After the spheroidizing medium stops flowing out of the spheroidizing chamber and stabilizes, the creation of the spheroidizing space can be achieved. The spheroidizing medium can isolate oxygen and avoid the influence brought by the oxidation of the wire segment during the spheroidizing process.

[0037] Step 2: Create a preheating environment

[0038] Start the nitrogen generator to compress and purify the air, removing oil, moisture and particulate pollutants. The molecular sieve inside it will adsorb oxygen, carbon dioxide and water vapor, but allow nitrogen to pass through to generate nitrogen. When the nitrogen is introduced into the spheroidizing chamber through the gas guide pipe and the upper part inside it reaches a suitable oxygen-free environment, adjust the heating temperature of the first heating jacket using the first temperature control box according to the characteristics of the welding wire, so that the upper part inside the spheroidizing chamber reaches the specified preheating temperature.

[0039] Step 3: Set the spheroidizing heating temperature

[0040] While waiting for the preheating temperature to rise, adjust the heating temperature of the second heating jacket using the second temperature control box according to the characteristics of the spheroidizing medium and the welding wire. Check the temperature display connected to the temperature measuring probe. After the temperature displayed on the temperature display stabilizes at the ideal spheroidizing temperature, stop the operation and keep it warm for 10 minutes to make the temperature of the spheroidizing medium in the heating part uniform, avoid the influence of uneven temperature in the heating interval on the spheroidizing of the wire segment, and make the welding wire fully melt and spheroidize.

[0041] Step 4: Set the spheroidizing cooling temperature

[0042] While waiting for the temperature of the heating part to rise, connect the power supply to the condenser and add water to it. When the water reaches the water level line, stop adding water. Set the temperature according to the characteristics of the spheroidizing medium to cool the water and make the water circulate in the cooling chamber to reduce the temperature of the spheroidizing medium in the cooling part of the spheroidizing chamber, so that the molten solder balls can be quickly condensed and avoid deformation again.

[0043] Step 5: Prepare the wire segment

[0044] Place the wire reel on the wire cutting device to prepare the wire segment.

[0045] Step 6: Collect the solder balls

[0046] After the wire cutting device stops cutting, open the second ball valve. After all the solder balls and part of the spheroidizing medium fall between the second ball valve and the third ball valve, close the second ball valve and open the third ball valve to make them fall into the collection vessel. Then, after being cleaned and dried with a special cleaning agent, the required solder balls are made.

[0047] Advantageous technical effects of the present invention compared with the prior art:

[0048] (1) The present invention can be used for the preparation of solder balls with a diameter of 0.2 mm to 1.0 mm in microelectronic packaging, and can also realize the preparation of large-size solder balls with a diameter of more than 1.0 mm.

[0049] (2) A wire cutting device is used for cutting the welding wire. The cutting length and frequency can be adjusted independently, which is convenient for control during the preparation of the welding wire segment. The straightener and fixture can also be adjusted to adapt to welding wires of various sizes. A preheating part is added above the spheroidizing space to fully melt the welding wire segment, and nitrogen is filled into the spheroidizing chamber to prevent oxidation reaction during the heating of the welding wire segment. In order to avoid the influence of the increased spheroidizing interval caused by the thermal expansion of the spheroidizing medium on the preparation of the solder ball, a liquid outlet hole is provided on the side of the top of the spheroidizing chamber to discharge the expanded spheroidizing medium, ensuring that the spheroidizing interval remains unchanged. Since the welding wire segment needs to be heated and spheroidized in the spheroidizing medium, the temperature of the spheroidizing medium is increased by heating the outside of the spheroidizing chamber with a heat preservation heating sleeve. A hole is provided in the middle of the spheroidizing chamber for inserting a temperature measuring probe and sealed with high-temperature glue to ensure the stability and accuracy of the temperature of the spheroidizing medium. A condenser is used to provide circulating cold water, which can quickly condense the molten solder and prevent the deformation of the solder ball caused by untimely condensation.

[0050] (3) Based on the wire cutting and remelting method, the present invention uses a wire cutting device to cut the welding wire into segments at a certain frequency. Under the action of gravity, the welding wire segments pass through the preheating system, are fully melted therein, and then fall into the spheroidizing device filled with the spheroidizing medium. Under the action of the heating system, the welding wire segments are spheroidized under the combined action of surface tension, buoyancy, viscous resistance and gravity in the spheroidizing medium, and then are quickly condensed by the cooling system to realize the preparation of the solder ball, enhancing the efficiency and reliability of preparing the solder ball by wire cutting and remelting, and improving the quality of the solder ball product. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is a schematic structural diagram of the device for preparing uniform solder balls by the wire cutting and remelting method of the present invention.

[0052] Figure 2 It is a schematic structural diagram of the wire cutting device in the device for preparing uniform solder balls by the wire cutting and remelting method of the present invention.

[0053] Figure 3 It is a schematic structural diagram of the fixture part in the wire cutting device of the present invention.

[0054] Figure 4 It is a schematic diagram of the principle for preparing uniform solder balls of the present invention.

[0055] Figure 5 It is a flow chart for preparing uniform solder balls of the present invention.

[0056] Figure 6 It is a physical diagram of the uniform solder balls prepared by the present invention. Detailed implementation mode

[0057] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present invention will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0058] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0059] In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features.

[0060] Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0061] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", "connection" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific situations.

[0062] The electrical devices, controllers, etc. described in the present invention are all conventional settings, and the electrical connection methods are also conventional connections.

[0063] As Figure 1 shown, the device for preparing uniform solder balls by the wire cutting and remelting method of the present invention includes a wire cutting device 27 and a spheroidizing device. The spheroidizing device includes a spheroidizing cavity 7, a flared opening 1 provided at the top of the spheroidizing cavity 7, and a steel frame 25;

[0064] The spheroidizing chamber 7 is used to store the spheroidizing medium, which is made of a material resistant to high temperatures of 800 °C, and is divided into a preheating section, a heating section, and a cooling section. The height of the preheating section is at least 0.4 m, the height of the heating section is at least 0.7 m, and the height of the cooling section is at least 0.5 m;

[0065] The flared opening 1 prevents the welding wire from falling outside the spheroidizing chamber 7;

[0066] The steel frame 25 ensures that the spheroidizing chamber 7 remains vertical, avoiding the influence on the preparation of welding balls caused by the welding wire falling and hanging on the wall due to the inclination of the spheroidizing chamber 7.

[0067] At the upper part of the spheroidizing chamber 7 is the preheating system of the preheating section, and from top to bottom on its outside are successively arranged a first heating jacket 2 and a hole connecting the gas guide pipe 5; in the middle part is the liquid control system, with a first liquid guide pipe 8 and a second liquid guide pipe 12 arranged on both sides respectively; at the upper part of the lower part is the heating system of the heating section, with a second heating jacket 14 arranged on the outside and a hole in the middle for arranging the temperature measuring probe 17; at the lower part of the lower part is the cooling system of the cooling section, with a cooling chamber 19 arranged on the outside; below it is arranged a collection vessel 26 as the collection system; above the flared opening 1 is arranged a wire cutting device 27, and the center of the flared opening 1 is aligned with the lower end of the slope 36 of the wire cutting device 27.

[0068] The preheating system of the spheroidizing device includes a first heating jacket 2, a temperature control box 4 connected to the first heating jacket 2 by a first wire 3, a gas guide pipe 5, and a nitrogen generator 6 connected to the spheroidizing chamber 7 through the gas guide pipe 5;

[0069] The first heating jacket 2 is used to heat the internal space of the upper part of the spheroidizing chamber 7, contains a thermocouple to measure the temperature of the heating jacket, and has a heat insulation layer on the outside;

[0070] The first temperature control box 4 is used to control the temperature of the first heating jacket 2, and the adjustable temperature range is 0 - 600 °C, and the preheating temperature is above 400 °C;

[0071] The gas guide pipe 5 is used to guide nitrogen into the spheroidizing chamber 7 and is made of a high-temperature resistant material;

[0072] The nitrogen generator 6 uses the pressure swing adsorption technology to produce high-purity nitrogen and reduce the oxygen content in the internal space of the upper part of the spheroidizing chamber 7.

[0073] The liquid control system in the spheroidizing device includes a first liquid guide pipe 8, a first ball valve 9 arranged at the top of the first liquid guide pipe 8, a pump 10 arranged in the middle of the first liquid guide pipe 8, a first liquid storage container 11 arranged at the bottom of the first liquid guide pipe 8 and connected together, a second liquid guide pipe 12, and a second liquid storage container 13 arranged at the bottom of the second liquid guide pipe 12 and connected together;

[0074] The first liquid guide tube 8 and the second liquid guide tube 12 can respectively guide the spheroidizing medium to flow into and out of the spheroidizing chamber 7, and are made of high-temperature resistant materials;

[0075] The first liquid storage container 11 and the second liquid storage container 13 are used to store the spheroidizing medium;

[0076] The pump 10 is used to extract the spheroidizing medium in the first liquid storage container 11 and flow it into the spheroidizing chamber 7;

[0077] The first ball valve 9 is mainly used to prevent the spheroidizing medium in the spheroidizing chamber 7 from flowing back into the first liquid storage container 11.

[0078] The heating system in the spheroidizing device includes a second heating jacket 14, a second temperature control box 16 connected to the second heating jacket 14 by a second wire 15, a temperature measuring probe 17 connected to the spheroidizing chamber 7, and a temperature display 18 connected to the temperature measuring probe 17;

[0079] The second heating jacket 14 is used to heat the spheroidizing medium in the spheroidizing chamber 7, contains a thermocouple to measure the temperature of the heating jacket, and has a heat insulation layer outside;

[0080] The second temperature control box 16 is used to control the temperature of the second heating jacket, and the adjustable temperature range is 0 - 400 °C;

[0081] The temperature measuring probe 17 is used to measure the temperature of the spheroidizing medium in the spheroidizing chamber 7, and the temperature measuring range is -50 - 500 °C;

[0082] The temperature display 18 displays the temperature measured by the temperature measuring probe 17.

[0083] The cooling system in the spheroidizing device includes a cooling chamber 19, a third liquid guide tube 20, and a condenser 21 connected to the cooling chamber 19 through the third liquid guide tube 20;

[0084] There is cold water in the cooling chamber 19 to reduce the temperature of the spheroidizing medium in the spheroidizing chamber 7;

[0085] The condenser 21 is provided with a water filling port 22, water can be added, the water temperature is cooled by the condenser 21, and circulating cold water is provided for the cooling chamber 19 through the third liquid guide tube 20, and the adjustable temperature range is -30 - 30 °C.

[0086] The collection system in the spheroidizing device includes a collection vessel 26, a third ball valve 24 arranged above the collection vessel 26, and a second ball valve 23 arranged above the third ball valve 24;

[0087] The collection vessel 26 collects the part of the spheroidizing medium that falls and all the solder balls;

[0088] The second ball valve 23 and the third ball valve 24 are used to control the falling of the spheroidizing medium and the solder balls;

[0089] The third ball valve 24, as the second ball valve of the collection system, is used in cooperation with the second ball valve 23 to prevent all the spheroidizing medium in the spheroidizing chamber 7 from falling, thus playing a role in saving resources.

[0090] Such as Figure 2 、 3 As shown, the wire cutting device 27 is a prior art and can prepare wire segments with a length of more than 0.5 mm.

[0091] Specifically, the wire cutting device 27 includes a wire feeding rack 28, a straightener 29, a fixture 30, a wire feeding roller shaft 31, a voltage regulator 32 arranged above the wire feeding roller shaft 31, a controller 33 arranged below the wire feeding wheel shaft 31, a cutting tool 34, a frame 35, and a ramp 36; the wire feeding rack 28 is convenient to disassemble and can be used to replace and hold the wire coil; the straightener 29 can change the size of the passing gap to ensure that the wire is straight before being cut; the fixture 30 can clamp the wire, and cooperate with the straightener 29 to enhance the stability of wire feeding, reduce the gap in the length of each wire segment, and improve the wire cutting accuracy; the wire feeding roller shaft 31 can automatically feed the wire regularly and quantitatively; the voltage regulator 32 can adjust the pressure of the wire feeding roller shaft on the tin wire; the controller 33 can control the frequencies of the wire feeding roller shaft 31 and the cutting tool 34, adjust the size of the cutting length, and record the number of cutting times; the cutting tool 34 can cooperate with the wire feeding roller shaft 31 to prepare wire segments at the frequency set by the controller 33, and can ensure the uniformity of the wire segments; the frame 35 is the housing of the wire cutting device 27 and assembles various parts and auxiliary accessories in the form of a main body; a baffle with holes is provided at the lower end of the ramp 36 to prevent the wire segments from flying out of the spheroidizing device, and can make the wire segments vertically fall above the bell mouth 1, reducing the influence of the wire segments sticking to the inner wall of the spheroidizing chamber 7 on the experiment.

[0092] The device of the present invention can prepare uniform solder balls with a diameter of more than 1.0 mm.

[0093] Such as Figure 4 、 5 As shown, the production method of the device for preparing uniform solder balls by the wire cutting and remelting method includes the following steps:

[0094] Step 1, creating a spheroidizing space

[0095] Open the first ball valve 9 at the top of the first liquid delivery pipe 8 to keep the inside of the first liquid delivery pipe 8 unobstructed. Use the pump 10 in the middle of the first liquid delivery pipe 8 to introduce the spheroidizing medium in the first liquid storage container 11 into the spheroidizing chamber 7. When the spheroidizing medium flows from the spheroidizing chamber 7 to the liquid storage container 13 through the second liquid delivery pipe 12, it indicates that the specified spheroidizing interval height has been reached. Close the pump 10 and the first ball valve 9. After the spheroidizing medium stops flowing out of the spheroidizing chamber 7 and stabilizes, the creation of the spheroidizing space can be achieved. The spheroidizing medium can isolate oxygen and avoid the influence brought by the oxidation of the wire segments during the spheroidizing process;

[0096] Step 2, create a preheating environment

[0097] Start the nitrogen generator 6 to compress and purify the air, removing oil, moisture and particulate pollutants. The molecular sieve inside it will adsorb oxygen, carbon dioxide and water vapor, but let nitrogen pass through to generate nitrogen. When the nitrogen is introduced into the spheroidizing chamber 7 through the gas delivery pipe 5 and the upper part inside it reaches a suitable oxygen-free environment, adjust the heating temperature of the first heating sleeve 2 according to the characteristics of the wire using the first temperature control box 4, so that the upper part inside the spheroidizing chamber 7 reaches the specified preheating temperature;

[0098] Step 3, set the spheroidizing heating temperature

[0099] While waiting for the preheating temperature to rise, adjust the heating temperature of the second heating sleeve 14 according to the characteristics of the spheroidizing medium and the wire. Check the temperature display 18 connected to the temperature measuring probe 17. After the temperature displayed on the temperature display stabilizes at the ideal spheroidizing temperature, stop the operation and keep warm for 10 minutes to make the temperature of the spheroidizing medium in the heating part consistent, avoiding the influence of uneven temperature in the heating interval on the spheroidizing of the wire segments, and making the wire fully melt and spheroidize.

[0100] Step 4, set the spheroidizing cooling temperature

[0101] While waiting for the temperature of the heating part to rise, connect the power supply to the condenser 21 and add water to it. When the water reaches the water level line, stop adding water. Set the temperature according to the characteristics of the spheroidizing medium to cool the water and make the water circulate in the cooling bin 19 to reduce the temperature of the spheroidizing medium in the cooling part of the spheroidizing chamber 7, so that the molten solder balls can be quickly condensed and avoid deformation again;

[0102] Step 5, prepare wire segments

[0103] Place the wire reel on the unwinding rack 28, thread the wire through the straightener 29, use the clamp 30 to hold the wire, and place it straight into the gap of the feeding roller shaft 31. Use the voltage regulator 32 to adjust the pressure of the feeding roller shaft 31 on the wire so that it can just drive the wire to move. Connect the power supply to the wire cutting device 27, and use the controller 33 to set the feeding and cutting frequencies to control the feeding roller shaft 31 and the cutter 34 to cooperate in preparing wire segments;

[0104] Step 6: Collect solder balls

[0105] After the wire cutting device 27 stops cutting, open the second ball valve 23. After all the solder balls and part of the spheroidizing medium fall between the second ball valve 23 and the third ball valve 24, close the second ball valve 23, open the third ball valve 24, and let them fall into the collection vessel 26. Then, after being cleaned and dried with a special cleaning agent, the required solder balls are made.

[0106] Specifically, the upper part of the spheroidizing chamber 7 is a preheating part. A first heating sleeve 2 and a hole connecting the gas guide pipe 5 are sequentially arranged on the outside from top to bottom. Under the synergistic action of the components in this part, the wire segments can be fully melted, which is beneficial to their spheroidization in the heating part.

[0107] The first heating sleeve 2 is connected to the first temperature control box 4 through the first wire 3, and contains a thermocouple inside to measure its own temperature, which is used to heat the internal environment of the preheating part of the spheroidizing chamber 7. The outside is provided with a heat insulation layer, which is beneficial to controlling the temperature and reducing heat loss. The first temperature control box 4 is used to control the first heating sleeve 2 so that it can heat the preheating part of the spheroidizing chamber 7 to the specified temperature.

[0108] The gas guide pipe 5 is connected to the nitrogen generator 6 and is used to guide nitrogen into the spheroidizing chamber 7. It is made of high-temperature resistant material. The nitrogen generator 6 uses pressure swing adsorption (PSA) technology to produce high-purity nitrogen, reducing the oxygen content in the upper part of the internal space of the spheroidizing chamber 7. The nitrogen gas produced by this technology has a large volume, which is sufficient to create an oxygen-free environment in the preparation of solder balls.

[0109] In this embodiment, a first liquid guide pipe 8 and a second liquid guide pipe 12 made of high-temperature materials are respectively arranged on both sides of the middle part of the spheroidizing chamber 7.

[0110] A first ball valve 9 is arranged at the top of the first liquid guide pipe 3, and a pump 10 is arranged in the middle, connecting the spheroidizing chamber 7 and the first liquid storage container 11, which is used to guide the spheroidizing medium to flow from the first liquid storage container 11 into the spheroidizing chamber 7. The pump 10 is used to pump out the spheroidizing medium in the first liquid storage container 11 and flow it into the spheroidizing chamber 7. The first ball valve 9 is mainly used to prevent the spheroidizing medium in the spheroidizing chamber 7 from flowing back into the first liquid storage container 11 due to thermal expansion. The first liquid storage container 11 is used to store the unused spheroidizing medium.

[0111] The second liquid guide pipe 12 connects the spheroidizing chamber 7 and the second liquid storage container 13, which is used to guide the spheroidizing medium to flow out of the spheroidizing chamber 7 and into the second liquid storage container 13. The second liquid storage container 13 is mainly used to retain part of the spheroidizing medium overflowing due to thermal expansion, and is also used to judge whether the spheroidizing medium is full.

[0112] Under the synergistic action of the components in this part, the creation and control of the spheroidizing space can be realized.

[0113] In this embodiment, the upper half of the spheroidizing cavity 7 serves as the heating part, and a second heating sleeve 14 is arranged outside. There is a hole in the middle for arranging a temperature measuring probe 17. Under the synergistic action of the components in this part, the wire segments can be spheroidized under the combined influence of the spheroidizing medium and their own characteristics;

[0114] The second heating sleeve 14 is connected to the second temperature control box 16 through a second wire 15. It contains a thermocouple inside to measure its own temperature and is used to heat the spheroidizing medium in the spheroidizing cavity 7. There is a heat preservation layer outside to control the temperature and reduce heat loss. The second temperature control box 16 is used to adjust the temperature of the heating sleeve so that it can heat the spheroidizing medium in the spheroidizing cavity 7 to the specified temperature;

[0115] The temperature measuring probe 17 is connected to the temperature display 18 and is used to measure the temperature of the spheroidizing medium in the spheroidizing cavity 7. The temperature displayed by the temperature display 18 is the temperature measured by the temperature measuring probe 17 and serves as the final spheroidizing temperature.

[0116] In this embodiment, the lower half of the spheroidizing cavity 7 serves as the cooling part, and a cooling chamber 19 is arranged outside. Under the synergistic action of the components in this part, the molten solder balls can be quickly cooled and solidified;

[0117] The cooling chamber 19 is connected to the condenser 21 through a third liquid guide pipe 20. There is cold water inside to reduce the temperature of the spheroidizing medium in the spheroidizing cavity 7. The condenser 21 is provided with a water filling port for adding water. The condenser 21 cools the water temperature and provides circulating cold water for the cooling chamber 19 through the third liquid guide pipe 20.

[0118] In this embodiment, a collecting vessel 26 is arranged below the spheroidizing cavity 7;

[0119] The collecting vessel 26 is used to collect part of the spheroidizing medium and all the solder balls. A second ball valve 23 and a third ball valve 24 are connected above it. The second ball valve 23 and the third ball valve 24 are used to control the falling of the spheroidizing medium and the solder balls. Using them together can prevent all the spheroidizing medium in the spheroidizing cavity 7 from falling, playing a role in saving resources.

[0120] In this embodiment, a wire cutting device 27 is arranged above the bell mouth 1, and the center of the bell mouth 1 is aligned with the lower end of the slope 36 of the wire cutting device 27;

[0121] The wire cutting device 27 includes a feeding rack 28, a straightener 29, a fixture 30, a feeding roller shaft 31, a voltage regulator 32, a controller 33, a cutter 34, a frame 35, and a slope 36;

[0122] Among them, the wire feeding rack 28 can be used to replace and hold the wire coil; the straightener 29 can change the size of the passing gap to ensure that the wire is straight before being cut; the clamp 30 can clamp the wire, and cooperate with the straightener 29 to enhance the stability of wire feeding, reduce the gap in the length of each wire segment, and improve the wire cutting accuracy; the wire feeding roller shaft 31 can automatically feed the wire regularly and quantitatively; the voltage regulator 32 can adjust the pressure of the wire feeding roller shaft on the tin wire; the controller 33 can adjust the frequencies of wire feeding and cutting, adjust the size of the cutting length, and record the number of cutting times; the cutter 34 can cooperate with the wire feeding roller shaft 31 to prepare wire segments at the frequency set by the controller 33, and can ensure the uniformity of the wire segments; the frame 35 is the housing of the wire cutting device 27, which assembles each part and auxiliary accessories in the form of a main body and protects them from being damaged; at the lower end of the ramp 36, there is a baffle with holes to prevent the wire segments from flying out of the spheroidizing device, and can make the wire segments vertically fall above the bell mouth 1, reducing the influence of the wire segments sticking to the inner wall of the spheroidizing cavity 7 on the experiment; the wire cutting device can cut the wire regularly and quantitatively, and guide the wire segments into the spheroidizing cavity 7 for melting, spheroidizing and condensing. The product is shown in Figure 6 。

[0123] The device and method for preparing uniform solder balls by the wire cutting and remelting method of the present invention use a wire cutting device to replace manual cutting, use a nitrogen generator to ensure an oxygen-free environment, use a pump and a high-temperature liquid guide pipe to create and control a spheroidizing environment, and use a heat preservation heating sleeve and a condenser to keep the temperature stable. Compared with the common wire cutting and remelting method for preparing solder balls, it has the characteristics of accurate and fast cutting and a stable spheroidizing environment.

[0124] As the most common technology for preparing solder balls at present, the jet perturbation technology is applied in various related enterprises. However, this technology can only be used for the preparation of solder balls with a diameter of 0.2 mm to 1.0 mm in microelectronic packaging. With the gradual development of the laser solder ball welding technology, a market for the application of larger solder balls with a diameter of more than 1.0 mm has emerged. The wire cutting and remelting method, which is gradually declining due to the difficulty in controlling the quality of fine solder balls, has gradually shown its advantages of simple operation, good sphericity of the prepared solder balls, and easy size control compared with other methods in the preparation of large solder balls. Optimizing the device and operation method of the wire cutting and remelting method is the problem that needs to be solved at present.

[0125] Principle of this embodiment: Place the welding wire on the wire feeding rack arranged on the wire cutting device, adjust the straightener and the fixture so that the gap is sufficient for the welding wire to pass through, adjust the voltage regulator so that the feeding roller shaft presses on the welding wire, and use the controller to set a certain frequency to control the start of the feeding roller shaft and the cutting tool, so that the welding wire is cut into segments. The wire segments will expose from the holes in the baffle at the lower end of the slope and fall into the lower spheroidizing chamber under the action of gravity. At this time, the preheating part, heating part, and cooling part of the spheroidizing chamber have reached the set temperature and the environment is stable under the action of the preheating system, heating system, and cooling system. Under the multiple influences of surface tension, gravity, viscous resistance, and buoyancy, the wire segments are fully melted under the high-temperature conditions in the preheating part, then spheroidized in the spheroidizing medium in the high-temperature state of the heating part, and then cooled and solidified through the cooling part. Among them, nitrogen is filled into the preheating part by a nitrogen generator. After the spheroidizing medium in the heating part expands due to heating, it will flow out from the second liquid guide pipe, always maintaining the stability and oxygen-free state of the preparation environment. The condensed solder balls will stay at the bottom of the spheroidizing chamber. Through the coordinated action of the two ball valves below, the solder balls and part of the spheroidizing medium will fall into the collection container, realizing the high-quality and high-quantity preparation of solder balls.

[0126] The present invention uses the wire cutting and remelting method to replace the jet perturbation method to prepare solder balls, eliminating the restrictions on production by solder and devices when preparing large-sized solder balls. The device consists of a wire cutting device and a spheroidizing device. The wire cutting device is used to cut the welding wire into wire segments. The spheroidizing device includes six major systems: a spheroidizing system, a preheating system, a liquid control system, a heating system, a cooling system, and a collection system. The spheroidizing system, as the main body of the spheroidizing device, provides a spheroidizing environment; the preheating system is used to fully melt the wire segments; the liquid control system is used to stabilize the spheroidizing interval; the heating system is used to heat the spheroidizing medium to further keep the liquid solder in a liquid state and spheroidize in it; the cooling system is used to cool the spheroidizing medium to further cool and solidify the spheroidized solder; the collection system is used to collect the solder balls.

[0127] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An apparatus for preparing uniform solder balls by a wire cutting and remelting method, comprising a wire cutting device (27) and a spheroidizing device, characterized in that, The spheroidizing device includes a spheroidizing chamber (7), a flared opening (1) provided at the top of the spheroidizing chamber (7), and a steel frame (25); The spheroidizing chamber (7) is used to store the spheroidizing medium, made of a material resistant to 800 °C high temperature, and is divided into a preheating part, a heating part and a cooling part. The height of the preheating part is at least 0.4 m, the height of the heating part is at least 0.7 m, and the height of the cooling part is at least 0.5 m; The flared opening (1) prevents the welding wire from falling outside the spheroidizing chamber (7); The steel frame (25) ensures that the spheroidizing chamber (7) remains vertical, avoiding the influence on the preparation of welding balls caused by the welding wire falling and hanging on the wall due to the inclination of the spheroidizing chamber (7).

2. The device for preparing uniform solder balls by the wire cutting and remelting method according to claim 1, wherein, In the upper part of the spheroidizing chamber (7) is the preheating system of the preheating part, and a first heating jacket (2) and a hole for connecting a gas guide pipe (5) are sequentially arranged from top to bottom on the outside; the middle part is the liquid control system, and a first liquid guide pipe (8) and a second liquid guide pipe (12) are respectively arranged on both sides; the upper part of the lower part is the heating system of the heating part, a second heating jacket (14) is arranged on the outside, and there is a hole in the middle for setting a temperature measuring probe (17); the lower part of the lower part is the cooling system of the cooling part, and a cooling chamber (19) is arranged on the outside; a collecting vessel (26) serving as a collecting system is arranged below it; a wire cutting device (27) is arranged above the flared opening (1), and the center of the flared opening (1) is aligned with the lower end of the slope (36) of the wire cutting device (27).

3. The device for preparing uniform solder balls by the wire cutting and remelting method according to claim 2, characterized in that, The preheating system of the spheroidizing device includes a first heating jacket (2), a temperature control box (4) connected to the first heating jacket (2) by a first wire (3), a gas guide pipe (5), and a nitrogen generator (6) connected to the spheroidizing chamber (7) through the gas guide pipe (5); The first heating jacket (2) is used to heat the internal space of the upper part of the spheroidizing chamber (7), contains a thermocouple to measure the temperature of the heating jacket, and has a heat insulation layer on the outside; The first temperature control box (4) is used to control the temperature of the first heating jacket (2), and the adjustable temperature range is 0 - 600 °C, and the preheating temperature is above 400 °C; The gas guide pipe (5) is used to guide nitrogen into the spheroidizing chamber (7), made of a high-temperature resistant material; The nitrogen generator (6) uses pressure swing adsorption technology to produce high-purity nitrogen, reducing the oxygen content in the internal space of the upper part of the spheroidizing chamber (7).

4. The apparatus for preparing uniform solder balls by the wire cutting and remelting method according to claim 2, wherein The liquid control system in the spheroidizing device includes a first liquid guide pipe (8), a first ball valve (9) provided at the top of the first liquid guide pipe (8), a pump (10) provided in the middle of the first liquid guide pipe (8), a first liquid storage container (11) provided at the bottom of the first liquid guide pipe (8) and connected together, a second liquid guide pipe (12), and a second liquid storage container (13) provided at the bottom of the second liquid guide pipe (12) and connected together; The first liquid guide pipe (8) and the second liquid guide pipe (12) can respectively guide the spheroidizing medium to flow into and out of the spheroidizing chamber (7), made of a high-temperature resistant material; The first liquid storage container (11) and the second liquid storage container (13) are used to store the spheroidizing medium; The pump (10) is used to pump out the spheroidizing medium in the first liquid storage container (11) and flow it into the spheroidizing chamber (7); The first ball valve (9) is mainly used to prevent the spheroidizing medium in the spheroidizing chamber (7) from flowing back into the first liquid storage container (11).

5. The device for preparing uniform solder balls by the wire cutting and remelting method according to claim 2, characterized in that, The heating system in the spheroidizing device includes a second heating jacket (14), a second temperature control box (16) connected to the second heating jacket (14) by a second wire (15), a temperature measuring probe (17) connected to the spheroidizing chamber (7), and a temperature display (18) connected to the temperature measuring probe (17); The second heating jacket (14) is used to heat the spheroidizing medium in the spheroidizing chamber (7), contains a thermocouple to measure the temperature of the heating jacket, and has a heat insulation layer outside; The second temperature control box (16) is used to control the temperature of the second heating jacket, and the adjustable temperature range is 0 - 400 °C; The temperature measuring probe (17) is used to measure the temperature of the spheroidizing medium in the spheroidizing chamber (7), and the temperature measuring range is -50 - 500 °C; The temperature display (18) displays the temperature measured by the temperature measuring probe (17).

6. The device for preparing uniform solder balls by the wire cutting and remelting method according to claim 2, wherein, The cooling system in the spheroidizing device includes a cooling bin (19), a third liquid guide pipe (20), and a condenser (21) connected to the cooling bin (19) through the third liquid guide pipe (20); There is cold water in the cooling bin (19) to reduce the temperature of the spheroidizing medium in the spheroidizing chamber (7); The condenser (21) is provided with a water filling port (22), water can be added, the water temperature is cooled by the condenser (21), and circulating cold water is provided for the cooling bin (19) through the third liquid guide pipe (20), and the adjustable temperature range is -30 - 30 °C.

7. The device for preparing uniform solder balls by the wire cutting and remelting method according to claim 1, wherein, The collection system in the spheroidizing device includes a collection vessel (26), a third ball valve (24) arranged above the collection vessel (26), and a second ball valve (23) arranged above the third ball valve (24); The collection vessel (26) collects part of the falling spheroidizing medium and all the solder balls; The second ball valve (23) and the third ball valve (24) are used to control the falling of the spheroidizing medium and the solder balls; The third ball valve (24), as the second ball valve of the collection system, is used in cooperation with the second ball valve (23) to prevent all the spheroidizing medium in the spheroidizing chamber (7) from falling, playing a role in saving resources.

8. The device for preparing uniform solder balls by the wire cutting and remelting method according to claim 1, characterized in that, The wire cutting device (27) prepares wire segments with a length of more than 0.5 mm.

9. The device for preparing uniform solder balls by the wire cutting and remelting method according to claim 1, characterized in that, The prepared uniform solder balls have a diameter of more than 1.0 mm.

10. A production method using the device for preparing uniform solder balls by the wire cutting and remelting method as described in any one of claims 1-8, characterized in that, It includes the following steps: Step 1, create a spheroidizing space Open the first ball valve (9) at the top of the first liquid guide pipe (8) to keep the inside of the first liquid guide pipe (8) unobstructed, and use the pump (10) in the middle of the first liquid guide pipe (8) to introduce the spheroidizing medium in the first liquid storage container (11) into the spheroidizing chamber (7); when the spheroidizing medium flows from the spheroidizing chamber (7) to the liquid storage container (13) through the second liquid guide pipe (12), it means that the specified spheroidizing interval height has been reached. Close the pump (10) and the first ball valve (9). After the spheroidizing medium no longer flows out of the spheroidizing chamber (7) and stabilizes, the creation of the spheroidizing space can be achieved. The spheroidizing medium can isolate oxygen and avoid the influence brought by the oxidation of the wire segments during the spheroidizing process; Step 2, create a preheating environment Start the nitrogen generator (6) to compress and purify the air, removing oil, moisture, and particulate contaminants. The molecular sieve inside it will adsorb oxygen, carbon dioxide, and water vapor, but allow nitrogen to pass through, generating nitrogen. When the gas guide pipe (5) introduces nitrogen into the spheroidizing chamber (7) and makes the upper part inside reach a suitable oxygen-free environment, adjust the heating temperature of the first heating sleeve (2) using the first temperature control box (4) according to the characteristics of the welding wire, so that the upper part inside the spheroidizing chamber (7) reaches the specified preheating temperature. Step 3: Set the spheroidizing heating temperature While waiting for the preheating temperature to rise, adjust the heating temperature of the second heating sleeve (14) using the second temperature control box (16) according to the characteristics of the spheroidizing medium and the welding wire. Check the temperature display (18) connected to the temperature measuring probe (17). After the temperature displayed on the temperature display stabilizes at the ideal spheroidizing temperature, stop the operation and keep it warm for 10 minutes to make the temperature of the spheroidizing medium in the heating part uniform, avoiding the influence of uneven temperature in the heating range on the spheroidizing of the welding wire segment, and making the welding wire fully melt and spheroidize. Step 4: Set the spheroidizing cooling temperature While waiting for the temperature of the heating part to rise, connect the condenser (21) to the power supply and add water to it. When the water reaches the water level line, stop adding water. Cool the water according to the characteristics of the spheroidizing medium and set the temperature to make the water circulate in the cooling chamber (19), reducing the temperature of the spheroidizing medium in the cooling part of the spheroidizing chamber (7), so that the molten solder balls can be quickly condensed and avoid deformation again. Step 5: Prepare the welding wire segment Place the welding wire reel on the wire cutting device (27) to prepare the welding wire segment. Step 6: Collect the solder balls After the wire cutting device (27) stops cutting, open the second ball valve (23). After all the solder balls and part of the spheroidizing medium fall between the second ball valve (23) and the third ball valve (24), close the second ball valve (23), open the third ball valve (24), and let them fall into the collection container (26). Then, after being cleaned and dried with a special cleaning agent, the required solder balls are made.

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