Corrosion-resistant bonding aluminum wire and preparation method thereof
By adding Mg to the aluminum wire and preparing it using a specific process, a magnesium oxide film is formed, which solves the problem of performance degradation of bonded aluminum wire in a corrosive environment, achieves high corrosion resistance and stability, and reduces production costs.
Patent Information
- Application Number
- CN202510721596.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-30
- Publication Date
- 2025-08-15
AI Technical Summary
Existing bonded aluminum wires are prone to oxidation and corrosion in corrosive environments, resulting in degradation of electrical performance and even breakage, affecting the normal operation of electronic devices.
0.1%~0.8% Mg was added to the aluminum wire, and corrosion-resistant bonded aluminum wire was prepared by homogenization, extrusion, wire drawing and heat treatment, forming a dense magnesium oxide film to isolate corrosive substances and optimize the performance of the aluminum wire.
The corrosion resistance and elongation of bonded aluminum wires are significantly improved, production costs are reduced, toughness and stability of aluminum wires are enhanced, and fractures are avoided due to corrosion.
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of electronic packaging, and in particular to a corrosion-resistant aluminum bonding wire and a preparation method thereof. Background Art
[0002] In the field of electronic packaging, aluminum bonding wire is a crucial electronic material. It is a thin, filamentous metal material used to achieve electrical connections between chips and packaging housings or substrates. Due to its good conductivity, moderate cost, and relatively easy processing performance, aluminum bonding wire has been widely used in many fields, including semiconductor devices, integrated circuits, and LED lighting.
[0003] With the continuous development of electronic technology, the application environments of electronic devices are becoming increasingly complex and diverse, placing higher demands on the performance of aluminum bonding wires. In many practical applications, aluminum bonding wires are exposed to various corrosive environments, such as humid air and gases or liquids containing chemical substances. In corrosive environments, the surface of the aluminum wire is prone to chemical reactions such as oxidation and corrosion, resulting in a decrease in its electrical performance, such as increased resistance and decreased conductivity. Over long-term use, corrosion gradually erodes the internal structure of the aluminum wire, causing it to break. Once the bonding wire breaks, the electrical connection of the electronic device is interrupted, causing the entire device to malfunction and potentially even fail.
[0004] Therefore, it is necessary to develop a bonding aluminum wire with corrosion resistance. Summary of the Invention
[0005] The present invention provides a corrosion-resistant aluminum bonding wire and a preparation method thereof, which solves the problem of poor corrosion resistance of the aluminum bonding wire in the related art.
[0006] The technical solution of the present invention is as follows: The present invention provides a corrosion-resistant aluminum bonding wire, which is composed of the following components in weight percentage: Mg 0.1%~0.8%, and the balance Al and inevitable impurities.
[0007] The present invention also proposes a method for preparing a corrosion-resistant bonding aluminum wire, which is used to prepare the corrosion-resistant bonding aluminum wire, comprising the following steps: preparing the materials according to the target composition and then melting and casting at 750-800°C to obtain an aluminum billet; homogenizing and strengthening the aluminum billet under a protective gas; and then extruding and drawing the aluminum wire to obtain the aluminum wire; and heat treating, cooling, and winding the aluminum wire to obtain the bonding aluminum wire.
[0008] In the present invention, the melting and casting step can fully mix multiple elements with the aluminum matrix, laying the foundation for subsequently obtaining bonding aluminum wire with uniform performance; the extrusion process helps to eliminate internal defects such as pores and shrinkage, making the organizational structure of the aluminum wire denser; the wire drawing process can accurately control the diameter of the bonding aluminum wire according to actual needs, meeting the strict requirements of different electronic devices on the size of the bonding wire; heat treatment is a key step for optimizing and stabilizing the performance of the aluminum wire. Through a suitable heat treatment process, the work hardening generated during the wire drawing process can be eliminated, and the plasticity and toughness of the aluminum wire can be restored; the connection between the various steps is smooth, which can realize large-scale continuous production and reduce production costs.
[0009] In the present invention, selecting a melting temperature of 750-800°C not only ensures that the aluminum and magnesium elements are fully melted to form a uniform liquid alloy, but also avoids the volatilization loss of elements due to excessively high temperatures, ensures the accuracy of the alloy composition, and avoids problems such as increased oxidation of the aluminum liquid caused by excessively high temperatures. From precise ingredient preparation and sufficient mixing to appropriate melting temperature and efficient continuous casting, all provide guarantees for obtaining aluminum billets with stable quality.
[0010] As a further technical solution, the extrusion includes the following steps: extruding the aluminum billet to obtain an aluminum rod with a diameter of 5 to 8 mm.
[0011] In the present invention, an aluminum rod is obtained by extruding an aluminum billet, so that the internal structure of the aluminum rod is denser, and the channels through which corrosive media may penetrate are reduced, thereby significantly improving the corrosion resistance of the aluminum rod and the subsequently produced bonding aluminum wire. At the same time, the dense structure also enhances the toughness of the aluminum rod, making it less likely to crack or break during subsequent processing.
[0012] As a further technical solution, the protective gas includes one or more of hydrogen, helium, argon, and nitrogen, preferably nitrogen.
[0013] As a further technical solution, the flow rate of the protective gas is 1.0-3.0 L / min, for example, it can be 1.0 L / min, 2.0 L / min, 3.0 L / min, and preferably 2.0 L / min.
[0014] As a further technical solution, the temperature of the homogenization treatment is 350~550℃, for example, it can be 350℃, 400℃, 450℃, 500℃, 550℃, preferably 450℃; the time is 10~48h, for example, it can be 10h, 15h, 18h, 20h, 25h, 30h, 35h, 40h, 45h, 48h, preferably 35h.
[0015] As a further technical solution, the temperature of the strengthening treatment is 400~600℃, for example, it can be 400℃, 450℃, 500℃, 550℃, 600℃, preferably 500℃, and the time is 1~5h, for example, it can be 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, preferably 3h.
[0016] As a further technical solution, the heat treatment temperature is 200-400°C, for example, 200°C, 250°C, 300°C, 350°C, 400°C, preferably 400°C, and the heat treatment holding time is 30-60 minutes.
[0017] In the present invention, a heat treatment temperature range of 200-400°C can cause the bonding aluminum wire to undergo a sufficient recrystallization process, so that the dislocations and distortions inside the aluminum wire can be released, promoting the nucleation and growth of new grains. A holding time of 30-60 minutes ensures that the recrystallization process is fully carried out, which helps to obtain a fine and uniform grain structure. It also makes the temperature inside the aluminum wire uniformly distributed, which is beneficial to eliminating the residual stress generated during the wire drawing process and further improving the performance of the bonding aluminum wire.
[0018] As a further technical solution, the cooling includes the following steps: after the aluminum wire is heat treated, it is cooled to 300°C at a first cooling rate, then cooled to 200°C at a second cooling rate, and finally cooled to room temperature at a third cooling rate.
[0019] As a further technical solution, the cooling rate of the third stage is less than the cooling rate of the first stage and less than the cooling rate of the second stage.
[0020] The present invention utilizes three cooling stages with varying cooling rates to precisely control the phase and structural transformations of the aluminum wire during cooling. The first stage, with a moderate cooling rate, helps further adjust the structural morphology and achieve a more uniform distribution of phases. The second stage, with a faster cooling rate, inhibits the formation of coarse phases and promotes the precipitation of fine dispersed phases. These fine phases act as dispersion strengthening, enhancing the strength of the aluminum wire. The third stage, with the slowest cooling rate, reduces thermal stresses generated during cooling, preventing cracks and deformation caused by rapid cooling. It also stabilizes the aluminum wire's structure, ensuring good toughness and plasticity, and ultimately improving the elongation of the bonded aluminum wire.
[0021] In the present invention, the first cooling stage is from the annealing temperature to 300°C at a relatively moderate cooling rate, which can inhibit the formation of some coarse grains and enable the atoms inside the aluminum wire to have sufficient time to diffuse and adjust to a certain extent, thereby laying the foundation for subsequent structural transformation; the second cooling stage is from 300°C to 200°C, which adopts a relatively fast cooling rate, thereby inhibiting some possible phase transformations that are detrimental to performance and promoting the precipitation of fine dispersed phases; the third cooling stage is from 200°C to room temperature, which adopts a slower cooling rate, thereby effectively reducing the thermal stress generated by the rapid temperature change, avoiding defects such as aluminum wire deformation and cracks caused by thermal stress, thereby optimizing the elongation of the bonded aluminum wire.
[0022] As a further technical solution, the cooling rate of the first section is 30~50℃ / h, for example, it can be 30℃ / h, 35℃ / h, 40℃ / h, 45℃ / h, 50℃ / h, and preferably 40℃; the cooling rate of the second section is 60~80℃ / h, for example, it can be 60℃ / h, 65℃ / h, 70℃ / h, 75℃ / h, 80℃ / h, and preferably 70℃ / h; the cooling rate of the third section is 10~20℃ / h, for example, it can be 10℃ / h, 15℃ / h, 20℃ / h, and preferably 20℃ / h.
[0023] In the present invention, the cooling rate of the first stage is 30-50°C / h, which is relatively moderate and helps to promote the homogenization of the internal structure of the aluminum wire and avoid problems such as uneven structure caused by excessive cooling, such as abnormal growth of local grains or component segregation. The cooling rate of the second stage is 60-80°C / h. The faster cooling rate can effectively reduce the diffusion and segregation of impurity elements at the grain boundaries and improve the stability of the grain boundaries. The cooling rate of the third stage is 10-20°C / h. The slow cooling process provides sufficient time for the internal structure of the aluminum wire to be further adjusted and stabilized, thereby improving the reliability and quality consistency of the product and enhancing the elongation of the bonded aluminum wire.
[0024] As a further technical solution, after the drawing, the diameter of the aluminum wire is 50-500 μm.
[0025] As a further technical solution, the wire drawing temperature is 70-80°C.
[0026] In the present invention, the aluminum rod is heated to 70-80°C. In this temperature range, the plasticity of the aluminum rod is significantly improved. Compared with wire drawing at room temperature, the heated aluminum is more likely to undergo plastic deformation and can be drawn into the required wire diameter under a smaller pulling force. This not only reduces the pulling force required in the wire drawing process and reduces the load on the equipment, but also reduces the risk of the aluminum wire breaking during the wire drawing process, thereby improving production stability and yield rate.
[0027] The working principle and beneficial effects of the present invention are: Unlike the prior art in which the raw material for bonding aluminum wire is high-purity aluminum, in the present invention, 0.1% to 0.8% of Mg is added to the raw material. When the aluminum wire is exposed to the air, the magnesium element, due to its active chemical properties, reacts with oxygen first, gradually forming a dense and continuous magnesium oxide film on the surface of the aluminum wire, effectively isolating the external oxygen, water and other corrosive substances from direct contact with the aluminum substrate; secondly, the addition of magnesium also changes the electrode potential on the surface of the aluminum wire. The aluminum wire no longer easily becomes an anode and undergoes an oxidation reaction, that is, loses electrons and is corroded. By controlling the content of magnesium, the corrosion resistance of the bonding aluminum wire is further improved. DETAILED DESCRIPTION
[0028] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.
[0029] Example 1 A corrosion-resistant aluminum bonding wire, the aluminum wire comprising the following components in weight percentage: 0.1% Mg, the balance being Al and unavoidable impurities; A method for preparing a corrosion-resistant bonding aluminum wire comprises the following steps: mixing materials according to target components, smelting at 750°C and then continuously casting to form an aluminum billet, homogenizing the aluminum billet at 450°C for 35 hours in a nitrogen atmosphere with a flow rate of 2 L / min, strengthening treatment at 500°C for 3 hours, extruding the aluminum billet to obtain an aluminum rod with a diameter of 5 mm, heating the aluminum rod to 70°C and performing wire drawing treatment to obtain an aluminum wire with a wire diameter of 50 μm, maintaining the temperature at 400°C for 60 minutes, and cooling after the end of the maintenance period. The cooling process comprises: controlling the cooling rate to 40°C / h, cooling to room temperature, and winding and packaging to obtain the bonding aluminum wire.
[0030] Example 2 A corrosion-resistant aluminum bonding wire, the aluminum wire comprising the following components in weight percentage: 0.5% Mg, the balance being Al and unavoidable impurities; A method for preparing a corrosion-resistant bonding aluminum wire comprises the following steps: mixing materials according to target components, smelting at 780°C and then continuously casting to form an aluminum billet; homogenizing the aluminum billet at 450°C for 35 hours in a nitrogen atmosphere with a flow rate of 2 L / min, strengthening treatment at 500°C for 3 hours, extruding the aluminum billet to obtain an aluminum rod with a diameter of 5 mm; heating the aluminum rod to 70°C and performing wire drawing treatment to obtain an aluminum wire with a wire diameter of 50 μm; maintaining the temperature at 400°C for 45 minutes; and cooling the aluminum wire after the end of the heat preservation process. The cooling process is as follows: cooling at a cooling rate of 40°C / h to room temperature, and packaging the aluminum wire to obtain the bonding aluminum wire.
[0031] Example 3 A corrosion-resistant aluminum bonding wire, the aluminum wire comprising the following components in weight percentage: 0.8% Mg, the balance being Al and unavoidable impurities; A method for preparing a corrosion-resistant bonding aluminum wire comprises the following steps: mixing materials according to target components, smelting at 800°C and then continuously casting to form an aluminum billet; homogenizing the aluminum billet at 450°C for 35 hours in a nitrogen atmosphere with a flow rate of 2 L / min, strengthening treatment at 500°C for 3 hours, extruding the aluminum billet to obtain an aluminum rod with a diameter of 5 mm; heating the aluminum rod to 70°C and performing wire drawing treatment to obtain an aluminum wire with a wire diameter of 50 μm; maintaining the temperature at 400°C for 30 minutes, and cooling after the end of the maintenance process. The cooling process is as follows: cooling at a cooling rate of 40°C / h, cooling to room temperature, and packaging the aluminum billet to obtain the bonding aluminum wire.
[0032] Example 4 Compared with Example 2, Example 4 is different in that the content of Mg is 0.4%.
[0033] Example 5 Compared with Example 2, Example 4 is different in that the Mg content is 0.6%.
[0034] Example 6 Compared with Example 2, Example 6 is different in that the cooling process of this embodiment is different. The cooling process of this embodiment includes the following steps: cooling to room temperature at a cooling rate of 70° C. / h.
[0035] Example 7 Compared with Example 2, Example 7 is different in that the cooling process of this embodiment is different. The cooling process of this embodiment includes the following steps: cooling to room temperature at a cooling rate of 20° C. / h.
[0036] Example 8 Compared with Example 2, the difference of Example 8 is that the cooling process of this embodiment is different. The cooling process of this embodiment includes the following steps: first cooling to 300°C at a cooling rate of 40°C / h, and then cooling to room temperature at a cooling rate of 70°C / h.
[0037] Example 9 Compared with Example 2, the difference of Example 9 is that the cooling process of this embodiment is different. The cooling process of this embodiment includes the following steps: first cooling to 300°C at a cooling rate of 40°C / h, and then cooling to room temperature at a cooling rate of 20°C / h.
[0038] Example 10 Compared with Example 2, the difference of Example 10 is that the cooling process of this embodiment is different. The cooling process of this embodiment includes the following steps: first cooling to 300°C at a cooling rate of 70°C / h, and then cooling to room temperature at a cooling rate of 40°C / h.
[0039] Example 11 Compared with Example 2, the difference of Example 11 is that the cooling process of this embodiment is different. The cooling process of this embodiment includes the following steps: first cooling to 300°C at a cooling rate of 70°C / h, and then cooling to room temperature at a cooling rate of 20°C / h.
[0040] Example 12 Compared with Example 2, the difference of Example 12 is that the cooling process of this embodiment is different. The cooling process of this embodiment includes the following steps: first cooling to 300°C at a cooling rate of 20°C / h, and then cooling to room temperature at a cooling rate of 40°C / h.
[0041] Example 13 Compared with Example 2, the difference of Example 13 is that the cooling process of this embodiment is different. The cooling process of this embodiment includes the following steps: first cooling to 300°C at a cooling rate of 20°C / h, and then cooling to room temperature at a cooling rate of 70°C / h.
[0042] Example 14 Compared with Example 2, the difference of Example 14 is that the cooling process of this embodiment is different. The cooling process of this embodiment includes the following steps: cooling to 300°C at a cooling rate of 40°C / h, then cooling to 200°C at a cooling rate of 70°C / h, and finally cooling to room temperature at a cooling rate of 20°C / h.
[0043] Example 15 Compared with Example 2, the difference of Example 15 is that the cooling process of this embodiment is different. The cooling process of this embodiment includes the following steps: cooling to 300°C at a cooling rate of 40°C / h, then cooling to 200°C at a cooling rate of 20°C / h, and finally cooling to room temperature at a cooling rate of 70°C / h.
[0044] Example 16 Compared with Example 2, the difference of Example 16 is that the cooling process of this embodiment is different. The cooling process of this embodiment includes the following steps: cooling to 300°C at a cooling rate of 70°C / h, then cooling to 200°C at a cooling rate of 20°C / h, and finally cooling to room temperature at a cooling rate of 20°C / h.
[0045] Example 17 Compared with Example 2, the difference of Example 17 is that the cooling process of this embodiment is different. The cooling process of this embodiment includes the following steps: cooling to 300°C at a cooling rate of 70°C / h, then cooling to 200°C at a cooling rate of 20°C / h, and finally cooling to room temperature at a cooling rate of 40°C / h.
[0046] Example 18 Compared with Example 2, the difference of Example 18 is that the cooling process of this embodiment is different. The cooling process of this embodiment includes the following steps: cooling to 300°C at a cooling rate of 20°C / h, then cooling to 200°C at a cooling rate of 70°C / h, and finally cooling to room temperature at a cooling rate of 40°C / h.
[0047] Example 19 Compared with Example 2, the difference of Example 19 is that the cooling process of this embodiment is different. The cooling process of this embodiment includes the following steps: cooling to 300°C at a cooling rate of 20°C / h, then cooling to 200°C at a cooling rate of 40°C / h, and finally cooling to room temperature at a cooling rate of 70°C / h.
[0048] Comparative Example 1 Compared with Example 2, Comparative Example 1 is different in that the content of Mg is 0.05%.
[0049] Comparative Example 2 Compared with Example 2, the difference in Comparative Example 2 is that the content of Mg is 1%.
[0050] Experimental Example 1 The aluminum bonding wires prepared in Examples 1 to 5 and Comparative Examples 1 to 2 were exposed to H2S for 200 h to observe whether corrosion spots appeared on the aluminum bonding wires, and to test the corrosion resistance of the samples.
[0051] The test results are shown in Table 1: Table 1 Performance test results of the bonding aluminum wires prepared in Examples 1 to 5 and Comparative Examples 1 to 2
[0052] It can be seen from Table 1 that when the Mg content is 0.1%~0.8%, the corrosion resistance of the bonding aluminum wire can be improved.
[0053] Experimental Example 2 The bonding aluminum wires prepared in Example 2 and Examples 6 to 19 were tested for elongation according to the test method specified in GB / T 228.1-2010 “Tensile tests on metallic materials - Part 1: Room temperature test methods”.
[0054] The test results are shown in Table 2: Table 2 Performance test results of the bonding aluminum wires prepared in Example 2 and Examples 6 to 19
[0055] It can be seen from Table 2 that when the cooling process is divided into three stages, and the cooling rate of the first stage is 40°C / h, the cooling rate of the second stage is 70°C / h, and the cooling rate of the third stage is 20°C / h, the elongation of the bonding aluminum wire can be further improved.
[0056] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.
Claims
1. A corrosion-resistant aluminum bonding wire, characterized in that: The aluminum wire is composed of the following components in weight percentage: 0.1% to 0.8% of Mg, and the balance of Al and inevitable impurities.
2. A method for preparing a corrosion-resistant aluminum bonding wire, for preparing the corrosion-resistant aluminum bonding wire according to claim 1, characterized in that: The following steps are involved: After the target composition is prepared, the aluminum billet is cast at 750-800°C, and then homogenized and strengthened under protective gas, and then extruded and drawn to obtain aluminum wire. The aluminum wire is heat treated, cooled, and rolled to obtain bonding aluminum wire.
3. The method for preparing a corrosion-resistant aluminum bonding wire according to claim 2, wherein: The extrusion process comprises the following steps: extruding an aluminum billet to obtain an aluminum rod with a diameter of 5 to 8 mm.
4. The method for preparing a corrosion-resistant aluminum bonding wire according to claim 2, wherein: The protective gas includes one or more of hydrogen, helium, argon and nitrogen.
5. The method for preparing a corrosion-resistant aluminum bonding wire according to claim 2, wherein: The homogenization treatment is performed at a temperature of 350-550° C. and for a time of 10-48 hours.
6. The method for preparing a corrosion-resistant aluminum bonding wire according to claim 2, wherein: The strengthening treatment is performed at a temperature of 400-600° C. and for a time of 1-5 hours.
7. The method for preparing a corrosion-resistant aluminum bonding wire according to claim 2, wherein: The cooling comprises the following steps: cooling the aluminum wire to 300° C. at a first cooling rate after heat treatment, cooling it to 200° C. at a second cooling rate, and finally cooling it to room temperature at a third cooling rate.
8. The method for preparing a corrosion-resistant aluminum bonding wire according to claim 7, characterized in that: The third stage cooling rate is less than the first stage cooling rate and less than the second stage cooling rate.
9. The method for preparing a corrosion-resistant aluminum bonding wire according to claim 7, wherein: The first stage cooling rate is 30-50°C / h, the second stage cooling rate is 60-80°C / h, and the third stage cooling rate is 10-20°C / h.
10. The method for preparing a corrosion-resistant aluminum bonding wire according to claim 2, wherein: After the drawing, the diameter of the aluminum wire is 50-500 μm.