Silver-based alloy bonding wire and preparation method thereof
By introducing copper, iron, and indium elements into silver-based alloy bonding wires and optimizing the preparation process, a high-performance infinite solid solution and uniform grain structure are formed, solving the problems of high cost and insufficient performance of existing silver-based alloy bonding wires, and realizing a lower cost and higher performance silver-based alloy bonding wire.
Patent Information
- Application Number
- CN202511153802.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-18
- Publication Date
- 2025-11-21
AI Technical Summary
Existing silver-based alloy bonding wires are insufficient to meet market demands in terms of cost and performance, especially in terms of resistance to thermal shock cycles. Furthermore, the alloy composition mainly relies on precious metals, resulting in high costs.
By using low-cost elements such as copper, iron, and indium as alloying components and adjusting their content, and through specific preparation processes such as smelting, continuous casting, stretching, and annealing, an infinite solid solution and a uniform grain structure are formed, thereby improving the alloy's electrical and thermal conductivity and mechanical strength.
It significantly improves the overall performance of silver-based alloy bonding wires, including tensile strength, shear force, wire pull, reliability, and workability, while reducing material costs.
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Abstract
Description
TECHNICAL FIELD
[0001] The application relates to the bonding wire processing technical field, in particular to a silver-based alloy bonding wire and a preparation method thereof. BACKGROUND
[0002] In the packaging process of the semiconductor LED light emitting diode at the present stage, silver-based alloy bonding wires with diameters ranging from 16 to 38 microns are commonly used as internal lead wires to connect chips and pins so that they can be electrically conducted and signal transmitted, that is, the bonding method of ball welding / wedge welding is used to press weld the soldering ball on the first welding point (chip), and the wedge welding method is used to lead out and weld the wire on the second welding point (pin connection electrode), that is, the technology of connecting the electrode welding area of the bare chip and the metal wiring welding area on the input / output lead wire or substrate of the electronic package with each other by using the metal bonding wire.
[0003] At present, the mainstream silver-based alloy bonding wire on the market generally contains 88.0-98.0% of silver, and uses noble metals such as gold, palladium and platinum as alloy components to form a multi-element alloy system. These alloy systems can basically meet the demand of the market for the bonding wire for LED packaging in terms of performance (especially reliability) (resisting more than 300 times of cold and hot impact cycles); however, with the change of market demand and market competition, the silver-based alloy bonding wire of the above alloy system cannot meet the market demand under the double pressure of cost and performance, and there is an urgent need for a silver-based alloy bonding wire with lower cost and higher performance on the market. SUMMARY
[0004] In order to overcome the defects of the above-mentioned silver-based alloy bonding wire and improve the comprehensive performance of the silver-based alloy bonding wire, the application provides a silver-based alloy bonding wire and a preparation method thereof.
[0005] In the first aspect, the application provides a silver-based alloy bonding wire which adopts the following technical scheme: A silver-based alloy bonding wire, the chemical element content is: 0.5wt%≤Cu≤1.1wt%, 0.006wt%≤Fe≤0.015wt%, 0.0005wt%≤In≤0.0015wt%, and the balance is Ag.
[0006] The silver-based alloy bonding wire of the application contains: 0.5wt%≤Cu≤1.1wt%, 0.006wt%≤Fe≤0.015wt%, 0.0005wt%≤In≤0.0015wt%, and the balance is Ag, the components can be selected as any value within the respective content range, and the comprehensive performance of the silver-based alloy bonding wire can be improved.
[0007] By adopting the technical scheme, silver is a good conductive and heat-conductive material, the alloy bonding wire uses silver as a base element to form an infinite solid solution, which can effectively improve the conductivity and heat-conductive performance of the bonding wire. The silver base can improve the strength and hardness of the bonding wire, so that the bonding wire has better wear resistance and corrosion resistance. The weldability of the bonding wire can also be improved, so that the bonding wire is more convenient and reliable in the manufacturing and assembling process.
[0008] When the copper content of the application is in the range of 0.5wt%-1.1wt%, the application can form a continuous solid solution with silver, reduce the grain boundary voltage, and cooperate with the preparation method of the application to improve the strength of the alloy, reduce the electrochemical corrosion, and enhance the breaking force of the alloy, which is beneficial to the subsequent stretching process of the alloy. Thus, the strength and hardness of the silver-based alloy bonding wire are increased.
[0009] On the basis of the above silver-copper alloy, the application adds 0.006wt%≤Fe≤0.015wt%. Fe and Ag can form an infinite solid solution, which increases the strength and hardness of the alloy. Within the composition range of the application, the heat treatment behavior of the silver-based alloy bonding wire can also be changed, which helps to adjust the heat treatment temperature and microstructure of the silver-based alloy bonding wire, thereby improving the performance of the alloy. The melting point and solidification behavior of the silver-based alloy bonding wire can also be changed, which helps to adjust the melting temperature and flow performance of the alloy. Moreover, the Fe element can affect the growth and morphology of the grains, thereby improving the microstructure and performance of the silver-based alloy bonding wire.
[0010] On the basis of the above alloy, the application adds 0.0005wt%≤In≤0.0015wt% of In element, which can improve the surface tension of the alloy liquid, improve the ball forming performance of the alloy during bonding, and further improve the wetting ability of the alloy on the surface of the aluminum plate, realize reliable welding between the aluminum plate and the silver-based alloy bonding wire, and also be beneficial to the anti-sulfur discoloration ability and oxidation resistance. The plastic toughness of the silver alloy is appropriately improved, and the ductility and toughness are improved.
[0011] The application contains three alloying elements of Cu, Fe and In, which synergistically act on the silver-based alloy bonding wire, play the role of multi-alloying, effectively solve the problem of corrosion resistance, maintain high conductivity and heat-conductive performance, reduce the cost of materials, and improve the comprehensive performance of the silver-based alloy bonding wire.
[0012] As a preferred embodiment, the silver-based alloy bonding wire contains the following chemical elements: 0.55wt%≤Cu≤0.95wt%, 0.007wt%≤Fe≤0.014wt%, 0.0006wt%≤In≤0.0012wt%, and the balance is Ag.
[0013] By adopting the technical scheme, the silver-based alloy bonding wire is prepared, the content is further adjusted to 0.55wt%≤Cu≤0.95wt%, 0.007wt%≤Fe≤0.014wt%, 0.0006wt%≤In≤0.0012wt%, and the balance is any value within the respective range of Ag, and the comprehensive performance of the silver-based alloy bonding wire can be improved.
[0014] In a second aspect, the application provides a preparation method of the silver-based alloy bonding wire.
[0015] The preparation method of the silver-based alloy bonding wire comprises the following steps: S1 silver-indium master alloy preparation: under the condition of vacuumizing and flushing in argon, the prepared indium element raw material and silver element raw material accounting for 8-12wt% of the total amount of all raw materials are heated and melted, and then cooled to room temperature to obtain a silver-indium master alloy ingot; S2 pre-alloy preparation: under the condition of vacuumizing and flushing in argon, the prepared copper element raw material, iron element raw material and S1 obtained silver-indium master alloy ingot are heated and melted with silver element raw material accounting for 20-30wt% of the total amount of all raw materials, and then cooled to room temperature to obtain a pre-alloy; S3 continuous casting: under the condition of vacuumizing and flushing in argon, the pre-alloy obtained in S2 and the remaining silver element raw material are heated and melted, and then continuously cast and drawn, and after the drawing is completed, a rod with a diameter of 7.0-7.5mm is obtained; S4 stretching: the rod obtained in S3 is sequentially subjected to a large / middle stretching process, a fine stretching process and a micro-fine stretching process to obtain a wire with a diameter of 0.018-0.030mm; S5 finished product annealing: the wire obtained in S4 is annealed in line to obtain a silver-based alloy bonding wire.
[0016] By adopting the technical scheme, first, the required raw materials are dosed according to the content of each element in the application, and then a silver-indium master alloy ingot is prepared, and a pre-alloy is further prepared. During alloy melting, the melting points of different metals have great differences, so the temperature is increased to the recrystallization temperature of the high-melting-point metal, so that the alloys with different melting points are mutually melted by high-temperature atomic diffusion to form metal compounds / infinite solid solutions, promote the stability of the crystal structure, and the grain is uniform, which can reduce the occurrence of intergranular precipitation.
[0017] The continuous casting process adopts directional solidification to accurately measure the raw materials and pre-alloys according to the ratio, and then continuously cast. The raw materials are heated, vacuumized, and filled with argon gas, which can effectively reduce the gas content in the silver-based alloy bonding wire, thereby improving the purity and uniformity of the silver-based alloy bonding wire; prevent the oxidation of the surface of the silver-based alloy bonding wire, reduce the defects and pores on the surface of the silver-based alloy bonding wire, eliminate the internal stress in the silver-based alloy bonding wire, and make the molten metal liquid start to produce vortex and churn, so that the composition of the silver-based alloy bonding wire is uniform and consistent, the segregation phenomenon is reduced, the continuous casting is started, and the diameter of the rod is 7.0-7.5mm.
[0018] The rod is sequentially subjected to large / middle stretching process, fine stretching process and micro stretching process to obtain a wire with a diameter of 0.018-0.030mm; the wire is continuously annealed in line to control the grain growth rate and make the grain size uniform; help to eliminate the internal stress in the silver-based alloy bonding wire and reduce the generation of deformation and cracks; promote the grain recrystallization and phase change of the silver-based alloy bonding wire, and improve the microstructure of the silver-based alloy bonding wire, thereby improving the mechanical properties and stability of the silver-based alloy bonding wire.
[0019] As preferred: the melting temperature in the preparation of the S2 silver-indium master alloy and the preparation of the S3 pre-alloy is 1400-1450℃, and the holding time is 120-150 minutes respectively.
[0020] By adopting the above technical scheme, the process conditions of the preparation of the S2 silver-indium master alloy and the S3 pre-alloy are matched, the melting temperature is adjusted to 1400-1450℃, the melting temperature can reach the recrystallization temperature, the silver-based alloy bonding wire is fully intermingled in the way of high-temperature atomic diffusion of silver-based alloy bonding wire materials with different melting points, and the various elements in the silver-based alloy bonding wire are fully mixed, thereby obtaining a uniform silver-based alloy bonding wire structure, and the holding time of 120-150 minutes can promote the phase change and grain growth in the silver-based alloy bonding wire, which is helpful to form a good grain structure and organization. The mutual cooperation of various conditions can eliminate the internal stress of the silver-based alloy bonding wire, improve the microstructure of the silver-based alloy bonding wire, and improve the plasticity and toughness of the silver-based alloy bonding wire, thereby improving the mechanical properties of the bonding wire.
[0021] As preferred: the temperature of the S3 continuous casting is 1000-1400℃, and the holding time is 15-20 minutes.
[0022] By adopting the above technical scheme, in the continuous casting process, the temperature is adjusted to 1000-1400℃, and the holding time is 15-20 minutes, which can ensure the uniformity of the silver-based alloy bonding wire structure, eliminate the internal stress, improve the grain size, promote the phase change, and improve the microstructure of the silver-based alloy bonding wire, thereby improving the comprehensive performance of the silver-based alloy bonding wire.
[0023] As preferred: the vacuum and argon injection conditions in the method are: first vacuum to 3x10 -3 -5x10 - 3 MPa, then argon injection to make the pressure rise to 0-0.2 MPa, and maintain the argon flow rate at 3-5 liters / minute.
[0024] By adopting the above technical solution, the oxygen and other impurity gases in the container can be removed by vacuuming to avoid affecting the alloy material. Then, the argon injection can provide an inert atmosphere during the preparation process to help maintain the purity and stability of the alloy material. At the same time, by controlling the argon injection to make the pressure in the range of 0-0.2 MPa, the alloy material can be properly protected to avoid contamination by oxygen or other impurity gases, improve the microstructure of the silver-based alloy bonding wire, and thus improve the quality and stability of the alloy bonding wire.
[0025] During continuous casting, under vacuum conditions, adjusting the argon flow rate to 3-5 liters / minute can form an argon protective layer to prevent the silver-based alloy bonding wire in the molten pool from being oxidized and contaminated by air, thereby protecting the stability and purity of the silver-based alloy bonding wire composition; argon can effectively reduce the oxidation reaction in the silver-based alloy bonding wire molten pool, thereby reducing the content of oxides and improving the quality and performance of the silver-based alloy bonding wire; it can also carry away impurities and bubbles in the molten pool, thereby purifying the silver-based alloy bonding wire and reducing the formation of internal defects; it can also help regulate the crystallization process of the molten pool, promote the uniform growth of silver-based alloy bonding wire grains, improve the grain structure of silver-based alloy bonding wire, and thus improve the overall performance of silver-based alloy bonding wire.
[0026] As preferred: the S4 stretching process obtains a wire with a diameter of 0.09-0.11 mm; the S4 stretching process obtains a wire with a diameter of 0.04-0.06 mm.
[0027] By adopting the above technical solution, adjusting the diameter of the wire obtained by the large / middle stretching process to be in the range of 0.09-0.11 mm and the diameter of the wire obtained by the fine stretching process to be in the range of 0.04-0.06 mm can make the grain size of the wire smaller and the defects and roughness of the wire surface less, which is more conducive to the subsequent micro-stretching process, improves the surface quality of the wire, and thus improves the microstructure of the silver-based alloy bonding wire and further improves the quality and performance of the silver-based alloy bonding wire.
[0028] As preferred: the S4 large / middle stretching process and fine stretching process further include a first annealing process; the first annealing temperature is 400-450℃, and the speed is 55-60 meters / minute.
[0029] By adopting the above technical solution, the first annealing process is carried out between the large / medium stretching process and the fine stretching process, and the first annealing temperature is adjusted to 400-450℃ and the speed is adjusted to 55-60m / min, so that the internal structure of the wire after large / medium stretching deformation is improved, and the problems of dislocation, stacking fault and other structure problems are solved. After the first annealing, the internal grains of the silver-based alloy bonding wire are rearranged, the internal stress caused by dislocation is preliminarily eliminated, the crystal lattice is restored to normal, the structure of the silver-based alloy bonding wire is improved, and the comprehensive performance of the silver-based alloy bonding wire is improved.
[0030] Preferably, the fine stretching process and the micro stretching process further include a second annealing process in S4. The second annealing temperature is 450-480℃, and the speed is 55-60m / min.
[0031] By adopting the above technical solution, the second annealing process is carried out between the fine stretching process and the micro stretching process, and the second annealing temperature is adjusted to 450-480℃ and the speed is adjusted to 55-60m / min, so that the micro stretching becomes more smooth, the internal stress of the material is preliminarily released and eliminated, the structure of the silver-based alloy bonding wire is improved, the plastic deformation ability of the material is improved, and the comprehensive performance of the silver-based alloy bonding wire is improved.
[0032] Preferably, the S5 product annealing temperature is 440-520℃, and the speed is 48-52m / min.
[0033] By adopting the above technical solution, the S5 product annealing temperature is adjusted to 440-520℃ and the speed is adjusted to 48-52m / min, so that the growth rate of the crystal grains is further controlled, the crystal grain size is uniform, the internal stress in the silver-based alloy bonding wire is eliminated, the deformation and crack are reduced, the grain recrystallization and phase change of the silver-based alloy bonding wire are promoted, the structure of the silver-based alloy bonding wire is improved, and the mechanical properties and stability of the silver-based alloy bonding wire are further improved.
[0034] In summary, the present application includes at least one of the following beneficial technical effects: (1) In the alloy system of the silver-based alloy bonding wire of the present application, no noble metal gold, palladium, platinum and other elements are used, but copper, iron and indium low-cost elements are used as alloy components, and the content of each element is adjusted, so that the comprehensive performance of the prepared silver-based alloy bonding wire is excellent.
[0035] (2) By adjusting each parameter in the preparation process of the silver-based alloy bonding wire, the comprehensive performance of the silver-based alloy bonding wire is improved.
[0036] (3) The application further improves the comprehensive performance of the silver-based alloy bonding wire by performing a first annealing process between the large / medium stretching process and the fine stretching process, performing a second annealing process between the fine stretching process and the micro stretching process, and adjusting the process parameters.
[0037] Therefore, the application uses copper, iron and indium low-cost elements as alloy components in the alloy system of the silver-based alloy bonding wire, adjusts the content of each element, adjusts various parameters in the silver-based alloy bonding wire preparation process, performs a first annealing process between the large / medium stretching process and the fine stretching process, performs a second annealing process between the fine stretching process and the micro stretching process, and adjusts the process parameters, so that the tensile strength, shear force, wire tension, reliability and workability of the obtained silver-based alloy bonding wire are highest, respectively 253 MPa, 44.2 g, 9.9 g, 510 times and 99 UPH, and the resistivity is minimum 1.52 µΩ / cm, which significantly improves the comprehensive performance of the silver-based alloy bonding wire. BRIEF DESCRIPTION OF DRAWINGS
[0038] Figure 1 is a flowchart of the preparation method provided by the application; Figure 2 is a characterization map of the appearance of the solder wire of Example 1 of the application; Figure 3 is a characterization map of the appearance of the solder wire after balling of Example 1 of the application; Figure 4 is a characterization map of the intermetallic compound (IMC) area on the surface of the solder wire after soldering of Example 1 of the application; Figure 5 is a metallographic graph of the balling property of Example 1 of the application. DETAILED DESCRIPTION
[0039] The application will be further described in detail below in combination with specific embodiments.
[0040] The following raw materials in the application are all commercially available products, which are disclosed to fully disclose the raw materials of the application, and should not be understood as limiting the source of the raw materials. Specifically: The raw materials of the application are selected as follows: silver particles with a purity of 99.999%; high-purity copper with a purity of 99.999%; high-purity iron with a purity of 99.999%; and high-purity indium with a purity of 99.95%. EMBODIMENT
[0041] Taking the silver-based alloy bonding wire with a finished diameter specification of 0.020 mm as an example, and the total raw material amount is 1000 grams. EMBODIMENT 1
[0042] The silver-based alloy bonding wire of Example 1 is prepared by the following preparation method: S1 silver-indium master alloy preparation: take 100g high purity silver particles (10wt% of the total amount of all raw materials), first put part of the high purity silver particles at the bottom of the alloy crucible, then put high purity indium on the silver particles, then pour the remaining silver particles into the crucible to completely cover the high purity indium, cover the crucible cover, vacuum to 2.5x10 -3 MPa, start heating to a temperature of 1350℃, keep for 110 minutes, and then flush argon to 0.1MPa, then turn off the heating system, start cooling to room temperature, take out the melted silver-indium master alloy ingot, remove the surface impurities, and prepare for use; S2 pre-alloy preparation: take 250g high purity silver particles (25wt% of the total amount of all raw materials), first put part of the high purity silver particles at the bottom of the alloy crucible, then put high purity copper, high purity iron and the silver-indium master alloy ingot obtained in S1 on the silver particles, then pour the remaining silver particles into the crucible to completely cover each raw material, cover the crucible cover, vacuum to 2.5x10 -3 MPa, start heating to a temperature of 1350℃, keep for 110 minutes, and then flush argon to 0.1MPa, then turn off the heating system, start cooling to room temperature, take out the melted pre-alloy ingot, remove the surface impurities, and prepare for use; S3 continuous casting: put the pre-alloy obtained in S2 and the remaining high purity silver particles together into a high purity graphite crucible, cover the continuous casting furnace, start vacuuming to 2.5x10 -3 MPa and fill argon to make the pressure 0.1MPa, and keep the argon flow at 2.5 liters / minute, then heat to 900℃ to melt each metal, and keep for 12 minutes, then adjust the heating power frequency to make the metal liquid in the furnace start to produce eddy current and churn, and keep for 10 minutes, then start continuous casting at a speed of 40mm / minute, after the end of the traction, clean the surface of the rod, remove the surface residual graphite particles, and get a rod with a diameter of 7.25mm; S4 stretching: the rod obtained in S3 is subjected to large / middle stretching process, the diameter is reduced to 0.15mm, fine stretching process, the diameter is reduced to 0.08mm, and micro-fine stretching process, the diameter is reduced to 0.020mm; S5 finished product annealing: the wire obtained in S4 is annealed in line continuously under the condition of a temperature of 400℃ and a speed of 40m / minute, and a silver-based alloy bonding wire is obtained, which is characterized by Figure 2 ; the appearance of the soldering wire after burning ball is characterized by Figure 3 ; the area of eutectic (IMC) on the surface of the soldering wire is characterized by Figure 4 ; the metallographic graph of ball forming is characterized by Figure 5 . Example 2-5
[0043] The silver-based alloy bonding wire of Examples 2-5 was prepared in the same manner as Example 1, except that the silver-based alloy bonding wire had different elemental contents, as shown in Table 1.
[0044] Table 1 Elemental contents of silver-based alloy bonding wire of Examples 1-5 (wt%) Cu Fe In Ag Example 1 0.5 0.006 0.0005 Balance Example 2 0.55 0.007 0.0006 Balance Example 3 0.75 0.01 0.00075 Balance Example 4 0.95 0.014 0.0012 Balance Example 5 1.1 0.015 0.0015 Balance Examples 6-7
[0045] The silver-based alloy bonding wire of Examples 6-7 was prepared in the same manner as Example 1, except that the annealing conditions of S5 finished product were 440°C at a speed of 48 m / min and 520°C at a speed of 52 m / min, respectively. Example 8
[0046] The silver-based alloy bonding wire of Example 8 was prepared in the same manner as Example 1, except that the temperature of smelting in the preparation of S1 silver-indium master alloy and S2 pre-alloy was 1400°C, and the holding time was 120 minutes, respectively. Example 9
[0047] The silver-based alloy bonding wire of Example 9 was prepared in the same manner as Example 1, except that the temperature of smelting in the preparation of S1 silver-indium master alloy and S2 pre-alloy was 1450°C, and the holding time was 150 minutes, respectively. Example 10
[0048] The silver-based alloy bonding wire of Example 10 was prepared in the same manner as Example 1, except that the temperature of continuous casting of S3 was 1000°C, and the holding time was 15 minutes. Example 11
[0049] The silver-based alloy bonding wire of Example 11 was prepared in the same manner as Example 1, except that the temperature of continuous casting of S3 was 1400°C, and the holding time was 20 minutes. Example 12
[0050] The silver-based alloy bonding wire of Example 12 was prepared in the same manner as Example 1, except that the conditions of vacuumizing and injecting argon were as follows: vacuumizing to 3 x 10 -3 MPa, then injecting argon to make the pressure rise to 0 MPa, and keeping the flow rate of argon at 5 L / min. Example 13
[0051] The silver-based alloy bonding wire of Example 13 was prepared in the same manner as Example 1, except that the conditions of vacuumizing and injecting argon were as follows: vacuumizing to 5 x 10 -3 MPa, then injecting argon to make the pressure rise to 0.2 MPa, and keeping the flow rate of argon at 3 L / min. Example 14
[0052] The preparation method of the silver-based alloy bonding wire of Example 14 is the same as that of Example 1, except that the large / medium stretching process in S4 stretching obtains a wire with a diameter of 0.09 mm; the fine stretching process obtains a wire with a diameter of 0.04 mm. Example 15
[0053] The preparation method of the silver-based alloy bonding wire of Example 15 is the same as that of Example 1, except that the large / medium stretching process in S5 stretching obtains a wire with a diameter of 0.11 mm; the fine stretching process obtains a wire with a diameter of 0.06 mm. Examples 16-17
[0054] The preparation method of the silver-based alloy bonding wire of Examples 16-17 is the same as that of Example 1, except that a first annealing process is additionally performed between the large / medium stretching process and the fine stretching process in S5; the conditions of the first annealing are respectively: temperature 400℃, speed 55m / min, temperature 450℃, speed 60m / min. Examples 18-19
[0055] The preparation method of the silver-based alloy bonding wire of Examples 18-19 is the same as that of Example 16, except that a second annealing process is additionally performed between the fine stretching process and the micro-fine stretching process in S5; the conditions of the second annealing are respectively: temperature 450℃, speed 55m / min, temperature 480℃, speed 60m / min. Comparative Examples
[0056] Comparative Examples 1-2 The preparation method of the silver-based alloy bonding wire of Comparative Examples 1-2 is the same as that of Example 1, except that the element contents of the silver-based alloy bonding wire are different, which are specifically shown in Table 2.
[0057] Table 2 Element contents (wt%) of silver-based alloy bonding wire of Comparative Examples 1-2 Cu Fe In Ag Comparative Example 1 0.4 0.005 0.0004 Balance Comparative Example 2 1.2 0.016 0.0016 Balance Performance detection
[0058] The silver-based alloy bonding wires obtained in different Examples 1-19 and Comparative Examples 1-2 are subjected to performance detection according to GB / T34502-2017 standard, wherein the reliability is embodied by cold and hot impact cycle experiment on the silver-based alloy bonding wire, and the detection results are shown in Table 3.
[0059] Table 3 Performance detection results of different silver-based alloy bonding wires Tensile strength / MPa Shear force / g Wire pull / g Reliability (cold-heat shock cycle test) / times Resistivity / µΩ / cm Workability / UPH Example 1 235 36.1 8.0 400 1.86 96 Example 2 238 37.3 8.5 450 1.84 98 Example 3 241 39.8 9.8 500 1.83 99 Example 4 248 43.1 9.4 480 1.86 99 Example 5 236 37.1 8.1 410 1.80 97 Example 6 238 38.4 8.4 415 1.70 98 Example 7 241 38.5 8.4 410 1.82 99 Example 8 241 37.9 8.9 418 1.86 98 Example 9 245 38.2 8.2 430 1.78 99 Example 10 241 39.1 9.1 440 1.71 99 Example 11 239 36.9 9.2 450 1.76 99 Example 12 243 37.1 8.4 425 1.75 98 Example 13 245 37.5 8.5 461 1.74 98 Example 14 243 38.1 9.1 470 1.65 98 Example 15 240 38.0 8.4 430 1.70 99 Example 16 248 39.0 9.4 480 1.60 99 Example 17 247 39.1 9.5 481 1.61 98 Example 18 251 43.9 9.4 508 1.54 99 Example 19 253 44.2 9.9 510 1.52 99 Comparative Example 1 210 32.1 6.2 310 2.55 96 Comparative Example 2 207 31.4 6.1 300 2.90 96 The detection results of Table 3 show that the silver-based alloy bonding wire obtained in the application has the highest tensile strength, shear force, wire tension, reliability and workability of 253 MPa, 44.2 g, 9.9 g, 510 times and 99 UPH respectively, and the smallest resistivity of 1.52 µΩ / cm, which significantly improves the comprehensive performance of the silver-based alloy bonding wire.
[0060] In Examples 1-5, the tensile strength, shear force, wire tension, reliability and workability of the silver-based alloy bonding wire obtained in Examples 2-4 are all higher than those of Examples 1 and 5, and the resistivity is lower than that of Examples 1 and 5, indicating that when the content of the silver-based alloy bonding wire is 0.55wt%≤Cu≤0.95wt%, 0.007wt%≤Fe≤0.014wt%, 0.0006wt%≤In≤0.0012wt%, and the balance is Ag, it is more appropriate, which improves the comprehensive performance of the silver-based alloy bonding wire.
[0061] In Examples 1 and 6-7, the tensile strength, shear force, wire tension, reliability and workability of the silver-based alloy bonding wire obtained in Examples 6-7 are all higher than those of Example 1, and the resistivity is lower than that of Example 1, indicating that when the temperature of S5 finished product annealing is 440-520℃, it is more appropriate, which improves the comprehensive performance of the silver-based alloy bonding wire.
[0062] In Examples 1 and 8-9, the tensile strength, shear force, wire tension, reliability and workability of the silver-based alloy bonding wire obtained in Examples 8-9 are all higher than those of Example 1, and the resistivity is lower than that of Example 1, indicating that when the smelting temperature in the preparation of S1 silver-indium master alloy and S2 pre-alloy is 1400-1450℃, and the holding time is 120-150 minutes, it is more appropriate, which improves the comprehensive performance of the silver-based alloy bonding wire, which may be related to the fact that the smelting temperature in the preparation of S1 silver-indium master alloy and S2 pre-alloy is 1400-1450℃, and the holding time is 120-150 minutes, which can improve the microstructure of the silver-based alloy bonding wire.
[0063] In Examples 1 and 10-11, the tensile strength, shear force, wire tension, reliability and workability of the silver-based alloy bonding wire obtained in Examples 10-11 are all higher than those of Example 1, and the resistivity is lower than that of Example 1, indicating that when the temperature of S3 continuous casting is 1000-1400℃, and the holding time is 15-20 minutes, it is more appropriate, which improves the comprehensive performance of the silver-based alloy bonding wire, which may be related to the fact that adjusting the temperature of S3 continuous casting to 1000-1400℃ and the holding time to 15-20 minutes can improve the microstructure of the silver-based alloy bonding wire.
[0064] In Example 1 and Examples 12-13, the tensile strength, shear force, wire tension, reliability and workability of the silver-based alloy bonding wire obtained in Examples 12-13 are higher than those of Example 1, and the resistivity is lower than that of Example 1, indicating that it is more appropriate to increase the pressure to 0-0.2 MPa after the argon is flushed in the method, and to maintain the flow rate of argon at 3-5 liters / minute, which improves the comprehensive performance of the silver-based alloy bonding wire. This may be related to the fact that adjusting the pressure to 0-0.2 MPa after the argon is flushed in the method, and maintaining the flow rate of argon at 3-5 liters / minute, can promote the internal reaction of the silver-based alloy bonding wire.
[0065] In Example 1 and Examples 14-15, the tensile strength, shear force, wire tension, reliability and workability of the silver-based alloy bonding wire obtained in Examples 14-15 are higher than those of Example 1, and the resistivity is lower than that of Example 1, indicating that it is more appropriate to obtain wire with a diameter of 0.09-0.11 mm in the large / medium stretching process of S4 stretching, and to obtain wire with a diameter of 0.04-0.06 mm in the fine stretching process, which improves the comprehensive performance of the silver-based alloy bonding wire. This may be related to the fact that adjusting the diameter of the wire to 0.09-0.11 mm in the large / medium stretching process of S4 stretching, and to 0.04-0.06 mm in the fine stretching process, can improve the microstructure of the silver-based alloy bonding wire.
[0066] In Example 1 and Examples 16-17, the tensile strength, shear force, wire tension, reliability and workability of the silver-based alloy bonding wire obtained in Examples 16-17 are higher than those of Example 1, and the resistivity is lower than that of Example 1, indicating that it is more appropriate to perform the first annealing process between the large / medium stretching process and the fine stretching process in S4, and to adjust the temperature of the first annealing process to 400-450°C and the speed to 55-60 meters / minute, which improves the comprehensive performance of the silver-based alloy bonding wire. This may be related to the fact that adjusting the temperature of the first annealing process to 400-450°C and the speed to 55-60 meters / minute between the large / medium stretching process and the fine stretching process in S4 can promote the rearrangement of the internal grains of the silver-based alloy bonding wire and eliminate abnormal internal stress.
[0067] In the embodiments 16 and 18-19, the tensile strength, shear force, wire tension, reliability and workability of the silver-based alloy bonding wire obtained in the embodiments 18-19 are higher than those of the embodiment 14, and the resistivity is lower than that of the embodiment 1, indicating that when the second annealing process is performed between the fine drawing process and the micro drawing process in S4, and the temperature of the second annealing is adjusted to 450-480°C and the speed is adjusted to 55-60 m / min, the comprehensive performance of the silver-based alloy bonding wire is improved, which may be related to the fact that the second annealing process is performed between the fine drawing process and the micro drawing process in S4, and the temperature of the second annealing is adjusted to 450-480°C and the speed is adjusted to 55-60 m / min, which can promote the micro drawing to be more smooth, and the initial release and elimination of the internal stress of the material.
[0068] In addition, according to the index data of the silver-based alloy bonding wire of the comparative examples 1-2 and the embodiment 1, it is found that when the content of the silver-based alloy bonding wire includes 0.5wt%≤Cu≤1.1wt%, 0.006wt%≤Fe≤0.015wt%, 0.0005wt%≤In≤0.0015wt%, and the balance is Ag, the comprehensive performance of the silver-based alloy bonding wire can be improved to different degrees.
[0069] The specific embodiments are only an explanation of the present application, and are not a limitation of the present application. Those skilled in the art can make modifications to the embodiments without creative contribution after reading the present specification, and the modifications are protected by the patent law as long as they are within the scope of the claims of the present application.
Claims
1. A silver-based alloy bonding wire, characterized by, Chemical element content: 0.5wt%≤Cu≤1.1wt%, 0.006wt%≤Fe≤0.015wt%, 0.0005wt%≤In≤0.0015wt%, the balance being Ag.
2. The silver-based alloy bonding wire of claim 1, wherein, Chemical element content: 0.55wt%≤Cu≤0.95wt%, 0.007wt%≤Fe≤0.014wt%, 0.0006wt%≤In≤0.0012wt%, the balance being Ag.
3. A method of making a silver-based alloy bonding wire as claimed in either of claims 1 or 2 characterised in that, It comprises the following steps: S1 silver-indium master alloy preparation: under the condition of vacuum and argon flushing, the prepared indium element raw material and the silver element raw material accounting for 8-12wt% of the total amount of all raw materials are heated and melted, and then cooled to room temperature to obtain a silver-indium master alloy ingot; S2 pre-alloy preparation: under the condition of vacuum and argon flushing, the prepared copper element raw material, iron element raw material and S1 obtained silver-indium master alloy ingot are heated and melted with the silver element raw material accounting for 20-30wt% of the total amount of all raw materials, and then cooled to room temperature to obtain a pre-alloy; S3 continuous casting: under the condition of vacuum and argon flushing, the pre-alloy obtained in S2 and the remaining silver element raw material are heated and melted, and then continuous casting is performed, and after the traction is completed, a rod with a diameter of 7.0-7.5mm is obtained; S4 stretching: the rod obtained in S3 is sequentially subjected to a large / medium stretching process, a fine stretching process and a micro-fine stretching process to obtain a wire with a diameter of 0.018-0.030mm; S5 finished product annealing: the wire obtained in S4 is annealed in line to obtain a silver-based alloy bonding wire.
4. The method of claim 3, wherein the silver-based alloy bonding wire is prepared by the steps of: The melting temperature in the S1 silver-indium master alloy preparation and the S2 pre-alloy preparation is 1400-1450℃, and the holding time is 120-150 minutes respectively.
5. The method for preparing the silver-based alloy bonding wire according to claim 3, characterized in that, The temperature of the S3 continuous casting is 1000-1400℃, and the holding time is 15-20 minutes.
6. The method of claim 3, wherein the silver-based alloy bonding wire is prepared by the steps of: The vacuum and argon injection conditions in the method are: first vacuum to 3 x 10 -3 -5 x 10 -3 MPa, then inject argon to raise the pressure from 3 x 10 -3 -5 x 10 -3 MPa to 0-0.2 MPa, and maintain the argon flow at 3-5 L / min.
7. The method for preparing the silver-based alloy bonding wire according to claim 3, characterized in that, In the S4 stretching, the large / medium stretching process obtains a wire with a diameter of 0.09-0.11mm; and the fine stretching process obtains a wire with a diameter of 0.04-0.06mm.
8. The method for preparing the silver-based alloy bonding wire according to claim 3, characterized in that, The first annealing process is further included between the large / medium stretching process and the fine stretching process in the S4; the temperature of the first annealing is 400-450℃, and the speed is 55-60m / min.
9. The method of claim 8, wherein the silver-based alloy bonding wire is prepared by the steps of: The second annealing process is further included between the fine stretching process and the micro-fine stretching process in the S4; the temperature of the second annealing is 450-480℃, and the speed is 55-60m / min. 10. The method of claim 8, wherein the silver-based alloy bonding wire is prepared by the steps of: The temperature of the S5 finished product annealing is 440-520℃, and the speed is 48-52m / min.