Silver alloy, preparation method of silver alloy, production equipment of silver alloy and application of silver alloy

Abstract

The invention relates to the technical field of non-ferrous metal smelting, in particular to a silver alloy, a preparation method of the silver alloy, production equipment of the silver alloy and application of the silver alloy. The preparation method of the silver alloy comprises the steps that under the vacuum condition, metal silver and high-vapor-pressure metal are heated to be in a gaseous state and mixed to be uniform through ultrasound, and mixed metal vapor is obtained; and performing condensation and nucleation crystallization on the mixed metal steam to obtain the silver alloy. According to the method, the metal silver and the high-vapor-pressure metal are evaporated and ultrasonically mixed in the vacuum, so that dissimilar or various metals can be uniformly mixed in the form of atomic-level particles, the high-vapor-pressure metal elements are almost free of loss, and the high-vapor-pressure metal elements in the silver alloy obtained after condensation nucleation crystallization are accurate in content and uniform in component.

Description

Technical Field

[0001] The present invention relates to the technical field of nonferrous metal smelting, and specifically, to a silver alloy and a preparation method thereof, a silver alloy production equipment and applications; more specifically, to a silver alloy and a preparation method thereof, a silver alloy production equipment, a silver wire bonding production system and applications. Background Art

[0002] Silver and its alloys are widely used in the fields of electronics and electrical, pharmaceuticals and chemicals, disinfection and antibacterial, photosensitive materials, environmental protection, silver jewelry and craft products. Silver and its alloys have good electrical and thermal conductivity, good chemical stability, ductility and other characteristics, so they have broad prospects in the fields of semiconductor packaging and integrated circuits. The silver bonding wires used in the field of electronic packaging are usually doped with trace elements to increase the corrosion resistance and bonding reliability of silver, such as gold, magnesium, palladium and other elements.

[0003] However, during the silver alloy melting process, due to the inconsistency of the saturated vapor pressures of different metals, especially the easy volatilization of high vapor pressure metals, the medium and high vapor pressure metal elements in the silver alloy are easily lost, which in turn leads to inaccurate content of high vapor pressure metal elements and uneven composition, which greatly reduces the performance of the bonding wire and its quality stability and consistency.

[0004] Although excessive addition of high vapor pressure metal elements can keep the alloy composition basically consistent with the expected composition, it still cannot solve the problem of uneven alloy composition and also increases the smelting cost.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] The first object of the present invention is to provide a method for preparing a silver alloy, by evaporating metallic silver and a high vapor pressure metal in a vacuum and ultrasonically mixing, heterogeneous or multiple metals can be mixed at the atomic level, and the high vapor pressure metal element is almost not lost, and the high vapor pressure metal element content in the silver alloy obtained after condensation nucleation and crystallization is accurate and uniform in composition. The problem of inaccurate content and uneven composition of high vapor pressure metal elements caused by the volatility of high vapor pressure metals in traditional smelting methods is solved.

[0007] The second object of the present invention is to provide a silver alloy in which the content of high vapor pressure metal elements is accurate and the composition is uniform.

[0008] The third purpose of the present invention is to provide a silver alloy production equipment, which can not only improve the uniformity of the silver alloy composition, but also reduce the burn loss during the smelting process of high vapor pressure metal, thereby improving the utilization rate of high vapor pressure metal.

[0009] A fourth object of the present invention is to provide a production system for bonding silver wires, which is beneficial to improving the quality stability and consistency of the bonding wires.

[0010] The fifth purpose of the present invention is to provide the application of the silver alloy obtained by the preparation method of the silver alloy or the silver alloy or the production equipment of the silver alloy or the production system of the bonding silver wire in the fields of electronics and electrical, photosensitive materials, aerospace and medical.

[0011] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0012] The present invention first provides a method for preparing a silver alloy, comprising the following steps: heating metallic silver and a high vapor pressure metal to a gaseous state under vacuum conditions, and uniformly mixing them by ultrasound to obtain mixed metal vapor; and obtaining the silver alloy after condensing and nucleating and crystallizing the mixed metal vapor.

[0013] Furthermore, the high vapor pressure metal includes at least one metal selected from the group consisting of magnesium, zinc, calcium, lithium, potassium, sodium, lead, samarium, europium, thulium, indium, ytterbium, and strontium.

[0014] Furthermore, the high vapor pressure metal is lead, and the mass fraction of the lead element in the silver alloy is 0.1% to 20%, preferably 2% to 20%.

[0015] Furthermore, the vacuum degree of the vacuum condition is 1×10 -6 Pa~0.34Pa.

[0016] Furthermore, the heating temperature is 962°C to 1200°C.

[0017] Furthermore, the frequency of the ultrasound is 3kHz to 5kHz.

[0018] Furthermore, after the metallic silver and the high vapor pressure metal are completely evaporated, the ultrasonic treatment is performed for 10 to 20 minutes.

[0019] Furthermore, the condensation time is 10 min to 40 min.

[0020] Furthermore, the mass of the high vapor pressure metal added before heating accounts for the total mass of the added metallic silver and the high vapor pressure metal as a percentage of W 1 The mass fraction of the high vapor pressure metal element in the silver alloy obtained after the condensation and nucleation crystallization is W 2 , then |W 1 -W 2 |≤0.0005.

[0021] Furthermore, |W 1 -W2 |≤0.0003.

[0022] The present invention further provides a silver alloy prepared by adopting the preparation method of the silver alloy.

[0023] The present invention further provides a silver alloy production equipment, which is suitable for the preparation method of the silver alloy, and the silver alloy production equipment includes a vacuum furnace tube, the vacuum furnace tube includes an evaporation zone and a flow zone connected to each other, and a condensation zone isolated from the flow zone by a sealing baffle; a high-temperature container is arranged inside the evaporation zone, and the high-temperature container is used to hold metallic silver and high-vapor-pressure metal; the evaporation zone is provided with a vacuum degree measuring instrument; a heating element device and an ultrasonic transmitting device are arranged outside the evaporation zone; the heating element device is used to heat and evaporate the metallic silver and the high-vapor-pressure metal, and the ultrasonic transmitting device is used to mix the evaporated metal vapor; a water cooling device is arranged outside the condensation zone, and the water cooling device is used to cool the condensation zone; the mixed metal vapor flows from the evaporation zone through the flow zone, and then enters the condensation zone to condense to form a silver alloy.

[0024] Furthermore, the vacuum furnace tube has an exhaust port.

[0025] Furthermore, first temperature measuring devices are respectively provided inside the evaporation zone and the flow zone.

[0026] Furthermore, a second temperature measuring device is provided inside the condensation zone.

[0027] Furthermore, the high temperature container includes a crucible.

[0028] The present invention further provides a production system for bonding silver wires, including production equipment for the silver alloy.

[0029] The present invention also provides the application of the silver alloy obtained by the preparation method of the silver alloy, or the silver alloy, or the production equipment of the silver alloy, or the production system of the bonding silver wire in the fields of electronics and electrical, photosensitive materials, aerospace and medical.

[0030] Furthermore, the electronic and electrical equipment includes a semiconductor package.

[0031] Furthermore, the silver alloy is mainly used to make bonding wires for the semiconductor package.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) The preparation method of the silver alloy provided by the present invention evaporates metallic silver and high vapor pressure metal in a vacuum and mixes them ultrasonically, thereby almost no loss of high vapor pressure metal elements is achieved, thereby improving the utilization rate of high vapor pressure metals. The content of high vapor pressure metal elements in the silver alloy obtained after condensation nucleation and crystallization is precise, the composition is uniform, and the structure is dense.

[0034] (2) The preparation method of the silver alloy provided by the present invention is based on the ideal gas law (Clapeyron equation) and the relationship between vapor pressure and temperature, so that heterogeneous or multiple metals are mixed and reorganized at the gas atomic level, which can greatly improve the uniformity of the silver alloy composition.

[0035] (3) The method for preparing the silver alloy provided by the present invention uses ultrasound to vibrate heterogeneous or multiple metal vapors, which can promote rapid mixing of multiple metal vapors and greatly improve the mixing efficiency.

[0036] (4) The method for preparing the silver alloy provided by the present invention can improve the purity of the silver alloy and reduce the content of impurity elements in the silver alloy, because the impurity metal elements with low vapor pressure do not evaporate but remain in the evaporation zone, thereby achieving separation from the silver element.

[0037] (5) The method for preparing the silver alloy provided by the present invention can make the elements that are difficult to dissolve in silver, such as lead, well dispersed with silver, thereby preparing a silver-lead alloy with a high lead content.

[0038] (6) The preparation method of the silver alloy provided by the present invention is simple to operate and easy to implement.

[0039] (7) The silver alloy production equipment provided by the present invention can not only improve the uniformity of the silver alloy composition, but also reduce the burn loss during the smelting process of high vapor pressure metal, thereby improving the utilization rate of high vapor pressure metal.

[0040] (8) The silver alloy production equipment provided by the present invention can improve the purity of the silver alloy and reduce the content of impurity elements in the silver alloy, because the impurity metal elements with low vapor pressure do not evaporate but remain in the evaporation zone, thereby achieving separation from the silver element.

[0041] (9) The silver alloy production equipment provided by the present invention can produce silver alloys with precise content of high vapor pressure metal elements and uniform composition, which is beneficial to improving the quality stability and consistency of the bonding wires produced thereby, thereby improving the performance of the bonding wires.

[0042] (10) The silver alloy production equipment provided by the present invention can mix and reorganize heterogeneous or multiple metals at the gas atom level by setting an evaporation zone, a heating element device and an ultrasonic emitting device, thereby achieving sufficient and uniform mixing of the silver alloy and obtaining a silver alloy with uniform composition and dense structure. At the same time, the use of ultrasound to vibrate heterogeneous or multiple metal vapors can promote rapid mixing of multiple metal vapors, greatly improve the mixing efficiency, and at the same time improve the uniformity of the silver alloy composition.

[0043] (11) The silver alloy production equipment provided by the present invention has a simple structure and is easy to apply on a large scale.

[0044] (12) The silver alloy production equipment provided by the present invention uses the silver alloy produced by the above-mentioned silver alloy production equipment to make bonding silver wires through the bonding silver wire production system, which can improve the consistency of the bonding silver wires and thus improve the performance of the bonding silver wires.

[0045] (13) The silver alloy production equipment provided by the present invention can prepare alloy products with low solid solubility of added elements in silver, such as Pb, to obtain silver-lead alloys with high lead content; wherein the three partitions are independent, and the metal gas can reach the condensation zone from the evaporation zone by self-diffusion, thermal motion and temperature gradient. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0047] Figure 1 This is a schematic structural diagram of the silver alloy production equipment provided by the present invention.

[0048] Reference numerals:

[0049] 100-vacuum furnace tube; 1-evaporation zone; 11-high temperature container; 12-heating element device; 13-ultrasonic transmitting device; 14-vacuum degree measuring instrument; 2-flow zone; 3-condensation zone; 31-water cooling device; 32-second temperature measuring device; 4-sealing baffle; 5-exhaust port; 6-first temperature measuring device. DETAILED DESCRIPTION

[0050] The technical scheme of the present invention will be clearly and completely described below in conjunction with specific embodiments, but it will be appreciated by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work, all belong to the scope of protection of the present invention. If specific conditions are not indicated in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not indicated in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0051] If there is no special explanation, in the present invention, "the first aspect", "the second aspect", "the third aspect", "the fourth aspect", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "the first", "the second", "the third", "the fourth", etc. only serve the purpose of non-exhaustive enumeration and description, and it should be understood that they do not constitute a closed limitation on quantity.

[0052] If there is no special explanation, the "include" and "comprising" mentioned in the present invention represent open-ended or closed-ended expressions. For example, the "include" and "comprising" may represent that other components not listed may also be included or only the listed components may be included or only the listed components may be included.

[0053] If there is no special explanation, in the present invention, "one or more" or "at least one" refers to any one, any two or more of the listed items. Among them, "several" refers to any two or more of the listed items.

[0054] In a first aspect, the present invention provides a method for preparing a silver alloy containing a high vapor pressure metal, comprising the following steps:

[0055] Under vacuum conditions, metallic silver and high vapor pressure metal are heated and evaporated to gaseous state at the same time, and the evaporated metallic silver vapor and high vapor pressure metal vapor are evenly mixed by ultrasound to obtain mixed metal vapor.

[0056] It can be understood that the above heating and ultrasonic processes are carried out in a closed system.

[0057] By means of ultrasonic vibration, heterogeneous or multiple metal vapors can be evenly mixed.

[0058] Under vacuum conditions, the mixed metal vapor is rapidly condensed, nucleated and crystallized to obtain a silver alloy with uniform composition.

[0059] The silver alloy prepared by the present invention can be widely used in various fields, especially in the field of semiconductor packaging. For example, the silver alloy can be used to prepare bonding wires.

[0060] The preparation method of the silver alloy provided by the present invention can make heterogeneous or multiple metals be mixed in atomic-level particles by evaporating metallic silver and high vapor pressure metal in a vacuum and ultrasonically mixing them, and the high vapor pressure metal element is almost not lost, and the high vapor pressure metal element content in the silver alloy obtained after condensation nucleation crystallization is accurate, the composition is uniform, and the structure is dense. The problem of inaccurate content and uneven composition of high vapor pressure metal elements caused by the high vapor pressure metal being easy to volatilize in the traditional smelting method is solved.

[0061] The preparation method of the silver alloy provided by the present invention is simple to operate and easy to implement. The method is based on the ideal gas law (Clapeyron equation) and the relationship between vapor pressure and temperature, so that different or multiple metals are mixed and reorganized at the gas atomic level, which can not only greatly improve the uniformity of the silver alloy composition, but also reduce the burning loss during the smelting process of high vapor pressure metals, thereby improving the utilization rate of high vapor pressure metals.

[0062] In addition, since impurity metal elements with low vapor pressure are not evaporated, they are separated from the silver element, thereby improving the purity of the silver alloy.

[0063] Furthermore, the present invention uses ultrasound to vibrate heterogeneous or multiple metal vapors, which can promote rapid mixing of multiple metal vapors and greatly improve mixing efficiency.

[0064] In addition, the present invention can prepare alloy products in which the solid solubility of the added element (such as Pb) in silver is low.

[0065] In some specific embodiments, the high vapor pressure metal includes at least one of magnesium, zinc, calcium, lithium, potassium, sodium, lead, samarium, europium, thulium, indium, ytterbium, and strontium.

[0066] The above-mentioned metallic silver and high vapor pressure metal can adopt any ratio commonly used in the art, and can be set specifically as needed, and the present invention is not limited to this. For example, the mass ratio of high vapor pressure metal to metallic silver is 0.01-30:70-99.9, but is not limited thereto.

[0067] The shapes of the metallic silver and the high vapor pressure metal may be arbitrary, and the present invention is not limited thereto.

[0068] In some specific embodiments, the metallic silver is silver with a purity of 3N or above.

[0069] In some specific embodiments, the high vapor pressure metal is lead, and the mass fraction of the lead element in the silver alloy is 0.1% to 20%, including but not limited to 0.1%, 0.3%, 0.5%, 0.8%, 1%, 1.3%, 1.5%, 1.7%, 2%, 3%, 5%, 8%, 10%, 12%, 15%, 18%, 20%, any one of the point values ​​or the range values ​​between any two of them; preferably, the mass fraction of the lead element in the silver alloy is 2% to 20%.

[0070] It is difficult to form a silver-lead alloy with a high lead content by using ordinary smelting process. At the eutectic temperature of 300°C, the maximum solubility of lead in silver is about 1.5%. However, as the temperature decreases, the solubility of lead in silver will drop sharply. At room temperature, lead is actually insoluble in silver.

[0071] The preparation method of the silver alloy provided by the present invention can make the elements that are difficult to dissolve in silver (such as lead) dispersed well and evenly with silver to prepare a silver-lead alloy with a high lead content, thereby solving the problem that it is difficult to form a silver-lead alloy with a high lead content by using traditional smelting processes of silver and lead.

[0072] In some specific embodiments, the vacuum degree of the vacuum condition is 1×10 -6 Pa~0.34Pa, including but not limited to 1×10 -6 Pa, 1×10 -5 Pa, 1×10 -4 Pa, 1×10 -3 Pa, 1×10 -2 Pa, 0.05Pa, 0.1Pa, 0.15Pa, 0.2Pa, 0.3Pa, 0.34Pa or any range between any two of them. The vacuum degree is related to the evaporation rate of the metal. The smaller the vacuum degree, the faster the evaporation rate. The present invention is beneficial to improving the evaporation rate of the metal and the generation efficiency by controlling the above vacuum degree.

[0073] In some specific embodiments, the heating temperature is 962° C. to 1200° C., including but not limited to any one of 962° C., 970° C., 980° C., 1000° C., 1030° C., 1050° C., 1080° C., 1100° C., 1130° C., 1150° C., 1170° C., and 1200° C. or any range between two of them. This temperature range can ensure that metallic silver and high vapor pressure metal evaporate to form gaseous metal.

[0074] In some specific embodiments, the ultrasonic frequency is 3kHz to 5kHz, including but not limited to any point value of 3kHz, 3.5kHz, 4kHz, 4.5kHz, and 5kHz or a range value between any two of them. The ultrasonic frequency is related to the mixing efficiency. The present invention controls the ultrasonic frequency within the above range to ensure sufficient vibration, thereby improving the mixing effect and ensuring uniform mixing.

[0075] In some specific embodiments, after the metallic silver and the high vapor pressure metal are completely evaporated, ultrasonic treatment is performed for 10 to 20 minutes, including but not limited to any one of 10 minutes, 13 minutes, 15 minutes, 18 minutes, and 20 minutes or any range between two of them. The ultrasonic treatment time can ensure that the gaseous metallic silver and the gaseous high vapor pressure metal are fully mixed and uniform, thereby facilitating further improving the uniformity of the composition of the silver alloy.

[0076] In some specific implementations, ultrasound can be turned on while heating and evaporating the metallic silver and the high vapor pressure metal, which is beneficial to improving the mixing efficiency.

[0077] In some specific embodiments, the condensation time is 10 min to 40 min, including but not limited to any point value of 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min or a range value between any two of them.

[0078] In some specific embodiments, the condensation temperature is 100°C to 200°C, including but not limited to any point value of 100°C, 120°C, 130°C, 150°C, 180°C, 200°C or a range between any two of them.

[0079] In some other specific embodiments, the condensation temperature may also be lower than 100°C.

[0080] In some specific embodiments, the mass of the high vapor pressure metal added before heating accounts for the total mass of the added metallic silver and the high vapor pressure metal as a percentage of W. 1 The mass fraction of the high vapor pressure metal element in the silver alloy obtained after the condensation and nucleation crystallization is W 2 , then |W 1 -W 2 |≤0.0005, preferably |W 1 -W 2 |≤0.0003, more preferably |W 1 -W 2 |≤0.0002.

[0081] In a second aspect, the present invention provides a silver alloy prepared by the above-mentioned silver alloy preparation method.

[0082] The silver alloy prepared by the above method has uniform composition and dense structure, and the content of high vapor pressure metal elements in the silver alloy is precise, which is conducive to the promotion and use of silver alloys.

[0083] In a third aspect, the present invention provides a production device for silver alloys, such as Figure 1 It is a schematic structural diagram of a silver alloy production device, which includes a vacuum furnace tube 100, and the vacuum furnace tube 100 is used to provide a vacuum environment.

[0084] See also Figure 1 The vacuum furnace tube 100 includes an evaporation zone 1 and a flow zone 2 which are interconnected, and a condensation zone 3 which is isolated from the flow zone 2 by a sealing baffle 4 .

[0085] That is, the evaporation zone 1 , the flow zone 2 , and the condensation zone 3 are arranged in sequence, wherein the evaporation zone 1 and the flow zone 2 are interconnected, and the flow zone 2 is separated from the evaporation zone 1 and the flow zone 2 by the sealing baffle 4 .

[0086] It can be understood that the sealing baffle 4 is movable and can be opened or closed.

[0087] See also Figure 1 A high-temperature container 11 is disposed inside the evaporation zone 1, and the high-temperature container 11 is used to contain metallic silver and high vapor pressure metal, that is, raw materials for preparing silver alloy.

[0088] Wherein, the high vapor pressure metal includes at least one of metal magnesium, metal zinc, metal calcium, metal lithium, metal potassium, metal sodium, metal lead, metal samarium, metal europium, metal thulium, metal indium, metal ytterbium and metal strontium.

[0089] See also Figure 1 A heating element device 12 and an ultrasonic emitting device 13 are arranged outside the evaporation zone 1 .

[0090] The heating element device 12 is used to heat and evaporate the metallic silver and the high vapor pressure metal to obtain gaseous metallic silver and gaseous high vapor pressure metal; the ultrasonic emitting device 13 is used to evenly mix the evaporated metal vapor, i.e., gaseous metallic silver and gaseous high vapor pressure metal.

[0091] See also Figure 1 The evaporation zone 1 is provided with a vacuum degree measuring instrument 14 , and the vacuum degree measuring instrument 14 is used to measure the vacuum degree in the evaporation zone 1 and the flow zone 2 .

[0092] In some specific embodiments, the vacuum degree measuring instrument 14 is arranged on the top of the evaporation zone 1, see Figure 1 shown.

[0093] See also Figure 1 A water cooling device 31 is provided outside the condensation zone 3 , and the water cooling device 31 is used to cool the condensation zone 3 ; or to condense the metal vapor in the condensation zone 3 .

[0094] The mixed metal vapor flows from the evaporation zone 1 through the flow zone 2 and then enters the condensation zone 3 to be condensed to form a silver alloy.

[0095] The silver alloy production equipment provided by the present invention can not only improve the uniformity of the silver alloy composition, but also reduce the burning loss during the smelting process of the high vapor pressure metal, thereby improving the utilization rate of the high vapor pressure metal.

[0096] Furthermore, impurity metal elements with low vapor pressure cannot evaporate and remain in the evaporation zone, thereby being separated from the silver element. Therefore, the silver alloy production equipment provided by the present invention can also improve the purity of the silver alloy.

[0097] The silver alloy produced by this production equipment has a precise content of high vapor pressure metal elements and a uniform composition, which is beneficial to improving the quality stability and consistency of the bonding wire produced therefrom, thereby improving the performance of the bonding wire.

[0098] Furthermore, the production system of bonding silver wire provided by the present invention can prepare alloy products with low solid solubility of added elements (such as Pb) in silver; the three partitions are independent, and the metal gas reaches the condensation zone 3 from the evaporation zone 1 by self-diffusion, thermal motion and temperature gradient.

[0099] Specifically, the present invention can mix and reorganize heterogeneous or multiple metals at the gas atom level by providing the evaporation zone 1, the heating element device 12 and the ultrasonic emitting device 13, thereby achieving sufficient and uniform mixing of the silver alloy and obtaining a silver alloy with uniform composition and compact structure. At the same time, the use of ultrasound to vibrate heterogeneous or multiple metal vapors can promote rapid mixing of multiple metal vapors, greatly improve the mixing efficiency, and at the same time improve the uniformity of the silver alloy composition.

[0100] In addition, the silver alloy production equipment provided by the present invention has a simple structure and is easy to promote and use.

[0101] Furthermore, the water cooling device 31 includes a water cooling jacket.

[0102] In some specific embodiments, the environment in which the metallic silver and the high vapor pressure metal are heated for evaporation and ultrasonically mixed is a vacuum environment.

[0103] Further, see Figure 1The vacuum furnace tube 100 has an exhaust port 5. The exhaust port 5 is used to exhaust the air in the vacuum furnace tube 100 to form a vacuum environment. The position of the exhaust port 5 can be set as needed, and the present invention does not limit this. For example, the position of the exhaust port 5 can be set on one side of the condensation zone 3, see Figure 1 shown.

[0104] Further, see Figure 1 A first temperature measuring device 6 is respectively provided inside the evaporation zone 1 and the flow zone 2 , and the first temperature measuring device 6 is used to detect the temperature inside the evaporation zone 1 and the flow zone 2 .

[0105] Furthermore, the first temperature measuring device 6 comprises a thermocouple. A thermocouple is a temperature measuring element commonly used in temperature measuring instruments, which directly measures temperature and converts temperature signals into thermoelectric potential signals, which are then converted into the temperature of the measured medium through an electrical instrument (secondary instrument).

[0106] Further, see Figure 1 A second temperature measuring device 32 is provided inside the condensation zone 3. The second temperature measuring device 32 is used to test the temperature inside the condensation zone 3 for condensing metal vapor.

[0107] In some specific implementations, the temperature of the condensation zone 3 is maintained at 100°C to 200°C.

[0108] Furthermore, the second temperature measuring device 32 includes a thermocouple.

[0109] Furthermore, the high temperature container 11 includes a crucible. A crucible is a cup-shaped container used to heat solids at high temperatures.

[0110] Furthermore, the crucible includes a graphite crucible. A graphite crucible, also known as a copper melting bag, a copper melting bag, etc., refers to a type of crucible made of graphite, clay, silica and wax stone as raw materials. A graphite crucible can be used to melt silver and its alloys.

[0111] Furthermore, the step of preparing the silver alloy using the above-mentioned silver alloy production equipment includes: placing metallic silver and high vapor pressure metal in a high temperature container 11 (such as a graphite crucible) in a vacuum furnace tube 100. Open the sealing baffle 4 in the vacuum furnace tube 100, perform a vacuum operation at the exhaust port 5, and evacuate until the vacuum degree in the vacuum furnace tube 100 is less than or equal to 0.34Pa, close the sealing baffle 4, heat the evaporation zone 1 of the vacuum furnace tube 100, and simultaneously turn on the ultrasonic emitting device 13, so that the temperature in the evaporation zone 1 and the flow zone 2 are both heated to above 962°C, and after the metallic silver and the high vapor pressure metal are completely evaporated, the ultrasound is maintained for a period of time to mix the metal vapors evenly. After mixing, open the sealing baffle 4, and the mixed metal vapor generated in the evaporation zone 1 flows through the flow zone 2 under the drive of the heat flow, and enters the condensation zone 3, and the mixed metal vapor condenses in the condensation zone 3, nucleates and crystallizes, and then cools to room temperature, that is, a silver alloy with uniform composition is obtained.

[0112] In a fourth aspect, the present invention provides a production system for bonding silver wires, including production equipment for the silver alloy.

[0113] The silver alloy produced by the above-mentioned silver alloy production equipment can be further made into bonding silver wire.

[0114] The above-mentioned silver bonding wire production system can improve the consistency of the silver bonding wire, thereby improving the performance of the silver bonding wire.

[0115] In a fifth aspect, the present invention provides a silver alloy obtained by the preparation method of the above-mentioned silver alloy or the application of the above-mentioned silver alloy in the electronic and electrical fields, the photosensitive material field, the aerospace field and the medical field.

[0116] In some specific implementations, the electronic and electrical field includes the semiconductor packaging field.

[0117] In some specific implementations, the silver alloy is mainly used to make bonding wires for the semiconductor package, but is not limited thereto.

[0118] The silver alloy provided by the present invention can be widely used in various fields, especially in the field of semiconductor packaging, wherein the silver alloy can be used to make bonding wires. The silver alloy has uniform composition and precise content of high vapor pressure metals, which is beneficial to improving the performance of the bonding wires and their quality stability and consistency.

[0119] The embodiments of the present invention will be described in detail below in conjunction with the examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present invention and should not be considered as limiting the scope of the present invention. If no specific conditions are specified in the examples, the conditions are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be obtained commercially.

[0120] Example 1

[0121] The method for preparing the silver alloy provided in this embodiment comprises the following steps:

[0122] Pure silver particles and pure magnesium particles are placed in a graphite crucible in a vacuum furnace tube, and the mass of the pure magnesium particles is 1% of the total mass of the pure silver particles and the pure magnesium particles. The vacuum furnace tube is evacuated until the vacuum degree in the vacuum furnace tube is 0.34 Pa, and the ultrasonic device is started, the ultrasonic frequency is 5kHz, and the heating power is turned on, and the temperature in the vacuum furnace tube is heated to 1200°C, so that the pure silver particles and the pure magnesium particles are evaporated into gaseous state. After the pure silver particles and the pure magnesium particles are completely evaporated, the ultrasonic maintenance time is 10 minutes to obtain mixed metal vapor.

[0123] The mixed metal vapor flows toward the condensation zone (water cooling, the temperature of the condensation zone is 150° C.) driven by the heat flow, and nucleates and crystallizes in the condensation zone. The condensation time is 30 minutes, and then it is cooled to room temperature to obtain a silver alloy.

[0124] Five samples were taken from different positions of the silver alloy prepared in this embodiment to test the magnesium content (mass fraction), and the average value of the magnesium content (mass fraction) of these five test points was calculated. The results are shown in Table 1 below.

[0125] In this embodiment, the mass of the high vapor pressure metal (magnesium) added before heating accounts for the total mass of the added metallic silver and the high vapor pressure metal as a percentage of W. 1 The mass fraction of the high vapor pressure metal element (magnesium) in the silver alloy obtained after condensation and nucleation crystallization is W 2 ,|W 1 -W 2 The values ​​of | are shown in Table 1 below.

[0126] Table 1 Magnesium content at each test point, average value of magnesium content and absolute value of absolute deviation

[0127]

[0128] Example 2

[0129] The method for preparing the silver alloy provided in this embodiment comprises the following steps:

[0130] Pure silver particles and pure magnesium particles are placed in a graphite crucible in a vacuum furnace tube, and the mass of the pure magnesium particles is 10% of the total mass of the pure silver particles and the pure magnesium particles. The vacuum furnace tube is evacuated until the vacuum degree in the vacuum furnace tube is 1×10 -2Pa, start the ultrasonic device with an ultrasonic frequency of 4 kHz, and turn on the heating power to heat the temperature in the vacuum furnace tube to 1100°C to evaporate the pure silver particles and pure magnesium particles into gas. After the pure silver particles and pure magnesium particles are completely evaporated, the ultrasonic maintenance time is 15 minutes to obtain mixed metal vapor.

[0131] The mixed metal vapor flows toward the condensation zone (water cooling, the temperature of the condensation zone is 120° C.) driven by the heat flow, and nucleates and crystallizes in the condensation zone. The condensation time is 20 minutes, and then it is cooled to room temperature to obtain a silver alloy.

[0132] Five samples were taken from different positions of the silver alloy prepared in this embodiment to test the magnesium content (mass fraction), and the average value of the magnesium content (mass fraction) of these five test points was calculated. The results are shown in Table 2 below.

[0133] In this embodiment, the mass of the high vapor pressure metal (magnesium) added before heating accounts for the total mass of the added metallic silver and the high vapor pressure metal as a percentage of W. 1 The mass fraction of the high vapor pressure metal element (magnesium) in the silver alloy obtained after condensation and nucleation crystallization is W 2 ,|W 1 -W 2 The values ​​of | are shown in Table 2 below.

[0134] Table 2 Magnesium content at each test point, average value of magnesium content and absolute value of absolute deviation

[0135]

[0136] Example 3

[0137] The method for preparing the silver alloy provided in this embodiment comprises the following steps:

[0138] Pure silver particles and pure magnesium particles are placed in a graphite crucible in a vacuum furnace tube, and the mass of the pure magnesium particles is 15% of the total mass of the pure silver particles and the pure magnesium particles. The vacuum furnace tube is evacuated until the vacuum degree in the vacuum furnace tube is 1×10 -4 Pa, start the ultrasonic device with an ultrasonic frequency of 3.5kHz, and turn on the heating power to heat the temperature in the vacuum furnace tube to 1000°C to evaporate the pure silver particles and pure magnesium particles into gas. After the pure silver particles and pure magnesium particles are completely evaporated, the ultrasonic maintenance time is 15 minutes to obtain mixed metal vapor.

[0139] The mixed metal vapor flows toward the condensation zone (water cooling, the temperature of the condensation zone is 180° C.) driven by the heat flow, and nucleates and crystallizes in the condensation zone. The condensation time is 40 minutes, and then it is cooled to room temperature to obtain a silver alloy.

[0140] Five samples were taken from different positions of the silver alloy prepared in this embodiment to test the magnesium content (mass fraction), and the average value of the magnesium content (mass fraction) of these five test points was calculated. The results are shown in Table 3 below.

[0141] In this embodiment, the mass of the high vapor pressure metal (magnesium) added before heating accounts for the total mass of the added metallic silver and the high vapor pressure metal as a percentage of W. 1 The mass fraction of the high vapor pressure metal element (magnesium) in the silver alloy obtained after condensation and nucleation crystallization is W 2 ,|W 1 -W 2 The values ​​of | are shown in Table 3 below.

[0142] Table 3 Magnesium content at each test point, average value of magnesium content and absolute value of absolute deviation

[0143]

[0144] Example 4

[0145] The preparation method of the silver alloy provided in this embodiment is basically the same as that in Embodiment 1, except that the pure magnesium particles are replaced with metal zinc blocks of equal mass.

[0146] Five samples were taken from different positions of the silver alloy prepared in this embodiment to test the zinc content (mass fraction), and the average value of the zinc content (mass fraction) of these five test points was calculated. The results are shown in Table 4 below.

[0147] In this embodiment, the mass of the high vapor pressure metal (zinc) added before heating accounts for the total mass of the added metallic silver and the high vapor pressure metal as a percentage of W. 1 The mass fraction of the high vapor pressure metal element (zinc) in the silver alloy obtained after condensation and nucleation crystallization is W 2 ,|W 1 -W 2 The values ​​of | are shown in Table 4 below.

[0148] Table 4 Zinc content at each test point, average zinc content and absolute value of absolute deviation

[0149]

[0150] Example 5

[0151] The preparation method of the silver alloy provided in this embodiment is basically the same as that in Embodiment 1, except that the pure magnesium particles are replaced with pure indium particles of equal mass.

[0152] Five samples were taken from different positions of the silver alloy prepared in this embodiment to test the indium content (mass fraction), and the average value of the indium content (mass fraction) of these five test points was calculated. The results are shown in Table 5 below.

[0153] In this embodiment, the mass of the high vapor pressure metal (indium) added before heating accounts for the total mass of the added metallic silver and the high vapor pressure metal as a percentage of W. 1 The mass fraction of the high vapor pressure metal element (indium) in the silver alloy obtained after condensation and nucleation crystallization is W 2 ,|W 1 -W 2 The values ​​of | are shown in Table 5 below.

[0154] Table 5 Indium content at each test point, average indium content and absolute value of absolute deviation

[0155]

[0156] It can be seen from the test results of the component contents of the various embodiments that, by adopting the preparation method of the silver alloy provided by the present invention, the content of high vapor pressure metal elements in the obtained silver alloy is accurate and the composition is uniform.

[0157] Comparative Example 1

[0158] The preparation method of the silver alloy provided in this comparative example is a smelting method, which specifically includes the following steps:

[0159] Place pure silver particles and pure magnesium particles in a graphite crucible in a vacuum furnace tube, and the mass of pure magnesium particles is 1% of the total mass of pure silver particles and pure magnesium particles. Evacuate the vacuum furnace tube until the vacuum degree in the vacuum furnace tube is 10 -3 Pa, and turn on the heating power, heat the temperature in the vacuum furnace tube to 1200℃, and keep the temperature for 30min. Then turn off the power, wait for the alloy to cool to room temperature, and get the silver alloy, then take out the alloy to test the composition.

[0160] Five samples were taken from different positions of the silver alloy prepared in this comparative example to test the magnesium content (mass fraction), and the average value of the magnesium content (mass fraction) of these five test points was calculated. The results are shown in Table 6 below.

[0161] In this comparative example, the mass of the high vapor pressure metal (magnesium) added before heating accounts for the total mass of the added metallic silver and the high vapor pressure metal as a percentage of W. 1 The mass fraction of the high vapor pressure metal element (magnesium) in the silver alloy obtained after the reaction is W 2 ,|W 1 -W 2 The values ​​of | are shown in Table 6 below.

[0162] Table 6 Magnesium content at each test point, average value of magnesium content and absolute value of absolute deviation

[0163]

[0164] By comparing Example 1 and Comparative Example 1, it can be seen that the vapor pressure metal element content of the silver alloy obtained by the traditional smelting method is not accurate and the composition is not uniform. However, Example 1 can make heterogeneous or multiple metals be mixed at the atomic level by evaporating metallic silver and high vapor pressure metal in a vacuum and ultrasonically mixing them, and there is almost no loss of high vapor pressure metal elements. The high vapor pressure metal element content in the silver alloy obtained after condensation nucleation crystallization is accurate and the composition is uniform.

[0165] Comparative Example 2

[0166] The preparation method of the silver alloy provided in this comparative example is basically the same as that of Example 1, except that ultrasound is not performed, but heating is continued for 10 minutes after the pure silver particles and the pure magnesium particles are completely evaporated to mix by natural diffusion.

[0167] Five samples were taken from different positions of the silver alloy prepared in this comparative example to test the magnesium content (mass fraction), and the average value of the magnesium content (mass fraction) of these five test points was calculated. The results are shown in Table 7 below.

[0168] In this comparative example, the mass of the high vapor pressure metal (magnesium) added before heating accounts for the total mass of the added metallic silver and the high vapor pressure metal as a percentage of W. 1 The mass fraction of the high vapor pressure metal element (magnesium) in the silver alloy obtained after the reaction is W 2 ,|W 1 -W 2 The values ​​of | are shown in Table 7 below.

[0169] Table 7 Magnesium content at each test point, average value of magnesium content and absolute value of absolute deviation

[0170]

[0171] By comparing Example 1 and Comparative Example 2, it can be seen that ultrasonic vibration of heterogeneous or multiple metal vapors can promote rapid and uniform mixing of multiple metal vapors, and the uniformity of the obtained silver alloy is better.

[0172] Although the present invention has been illustrated and described with specific embodiments, it should be appreciated that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Those skilled in the art should understand that the technical solutions described in the above embodiments may be modified, or some or all of the technical features thereof may be replaced by equivalents without departing from the spirit and scope of the present invention. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention. Therefore, this means that all such replacements and modifications within the scope of the present invention are included in the appended claims.

Claims

1. A method for preparing a silver alloy, characterized in that: The steps include: Under vacuum conditions, metallic silver and high vapor pressure metal are heated to gaseous state and uniformly mixed by ultrasonication to obtain mixed metal vapor; The mixed metal vapor is condensed and crystallized to obtain the silver alloy.

2. The method for preparing the silver alloy according to claim 1, characterized in that: The high vapor pressure metal includes at least one metal selected from the group consisting of magnesium, zinc, calcium, lithium, potassium, sodium, lead, samarium, europium, thulium, indium, ytterbium, and strontium.

3. The method for preparing the silver alloy according to claim 1, characterized in that: The high vapor pressure metal is lead, and the mass fraction of the lead element in the silver alloy is 0.1% to 20%, preferably 2% to 20%.

4. The method for preparing the silver alloy according to claim 1, characterized in that: At least one of the following conditions is met: (1) The vacuum degree of the vacuum condition is 1×10 -6 Pa~0.34Pa; (2) The heating temperature is 962° C. to 1200° C.; (3) The frequency of the ultrasound is 3kHz to 5kHz; (4) after the metallic silver and the high vapor pressure metal are completely evaporated, performing the ultrasonic treatment for 10 to 20 minutes; (5) The condensation time is 10 min to 40 min.

5. The method for preparing the silver alloy according to claim 1, characterized in that: The mass fraction of the high vapor pressure metal added before the heating to the total mass of the added metallic silver and the high vapor pressure metal is W1, and the mass fraction of the high vapor pressure metal element in the silver alloy obtained after the condensation and nucleation crystallization is W2, then |W1-W2|≤0.0005, preferably |W1-W2|≤0.0003.

6. A silver alloy prepared by the method for preparing a silver alloy as claimed in any one of claims 1 to 5.

7. A silver alloy production equipment, characterized in that: The method for preparing the silver alloy according to any one of claims 1 to 5, wherein the production equipment of the silver alloy comprises a vacuum furnace tube, wherein the vacuum furnace tube comprises an evaporation zone and a flow zone connected to each other, and a condensation zone isolated from the flow zone by a sealing baffle; A high-temperature container is provided inside the evaporation zone, and the high-temperature container is used to contain metallic silver and high vapor pressure metal; The evaporation zone is provided with a vacuum degree measuring instrument; A heating element device and an ultrasonic emitting device are provided outside the evaporation zone; the heating element device is used to heat and evaporate the metallic silver and the high vapor pressure metal, and the ultrasonic emitting device is used to mix the evaporated metal vapor; A water cooling device is provided outside the condensation zone, and the water cooling device is used to cool the condensation zone; The mixed metal vapor flows from the evaporation zone through the flow zone and then enters the condensation zone to be condensed to form a silver alloy.

8. The silver alloy production equipment according to claim 7, characterized in that: At least one of the following conditions is met: (1) The vacuum furnace tube has an exhaust port; (2) A first temperature measuring device is respectively provided inside the evaporation zone and the flow zone; (3) A second temperature measuring device is provided inside the condensation zone; (4) The high temperature container includes a crucible.

9. A production system for bonding silver wires, characterized in that: A production device comprising the silver alloy as described in any one of claims 7 to 8.

10. Application of the silver alloy obtained by the preparation method of the silver alloy according to any one of claims 1 to 5, or the silver alloy according to claim 6, or the production equipment of the silver alloy according to any one of claims 7 to 8, or the production system of the bonding silver wire according to claim 9 in the fields of electronics and electrical, photosensitive materials, aerospace and medical treatment; Preferably, the electronic device comprises a semiconductor package; More preferably, the silver alloy is mainly used to make bonding wires for the semiconductor package.

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