Preparation method of copper-manganese-aluminum ternary alloy cast ingot

Abstract

The invention relates to a preparation method of a copper-manganese-aluminum ternary alloy cast ingot, which comprises the following steps: carrying out first vacuum induction melting on a copper raw material to obtain molten copper liquid; adding an aluminum raw material into the copper liquid, and then standing to obtain a first mixed smelting liquid; adding a manganese raw material into the first mixed smelting solution, and then carrying out second vacuum induction smelting to obtain a second mixed smelting solution; the second mixed smelting solution is subjected to casting molding and cooling in sequence, and a copper-manganese-aluminum ternary alloy cast ingot is obtained; the weight percentage of aluminum in the copper-manganese-aluminum ternary alloy cast ingot is 0.01%-0.1%, and the weight percentage of manganese in the copper-manganese-aluminum ternary alloy cast ingot is 0.05%-0.2%. According to the preparation method provided by the invention, the oxygen content in the copper-manganese-aluminum ternary alloy can be reduced, so that the problem that particles are generated when the ternary alloy target material is sputtered is reduced, and meanwhile, the production cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of alloy smelting, and in particular to a method for preparing a copper-manganese-aluminum ternary alloy ingot. Background Art

[0002] Ultra-high purity (purity ≥ 99.9999%) copper and its alloys (such as copper-aluminum, copper-manganese) are key materials for integrated circuit chips. With the continuous advancement of integrated circuit technology, the application of copper-aluminum and copper-manganese alloys is becoming more and more extensive. By adding aluminum or manganese elements, the physical properties of copper alloys can be significantly improved.

[0003] However, the high activity of aluminum makes it easy to introduce oxygen impurities when producing copper-aluminum alloys, which may lead to the generation of oxide particles during the sputtering process, thereby increasing the scrap rate of chips. Although the high-purity manganese used in copper-manganese alloys is not easily oxidized, the cost is relatively high, resulting in the high price of copper-manganese alloys, which in turn increases the manufacturing cost of chips.

[0004] CN111197129A discloses a copper-aluminum-manganese alloy and a preparation method thereof. The copper-aluminum-manganese alloy contains chemical elements in the following mass fraction ratios: Al: 9.5-10.5%, Mn: 11.5-12.5%, and the remainder is Cu. The copper-aluminum-manganese alloy has a metallographic structure including a metastable β phase structure and an α phase dispersedly distributed within the crystal. The alloy is mainly used in situations requiring high strength and plasticity, such as heavy-duty bearing bushings, wear-resistant and pressure-resistant valve bodies in high-temperature chemical equipment, and elastic structural parts in peripheral equipment of nuclear reactors.

[0005] CN114318023A discloses a vacuum smelting method for a high-aluminum manganese copper alloy, the method comprising the following steps: (1) placing copper, nickel and cobalt into a crucible of an induction melting furnace; (2) evacuating the induction melting furnace and heating it electrically; when the charge begins to melt, argon is filled into the induction melting furnace for protection; (3) after the charge is melted, some aluminum particles are added, the aluminum particles melt and form a film on the liquid surface; then electrolytic manganese is added; after the electrolytic manganese is melted, the remaining aluminum particles are added until all the charge is melted; and (4) the melted material is cast into a water-cooled ingot mold and cooled with the furnace.

[0006] However, the above method is not suitable for the preparation of ultra-high purity copper-manganese-aluminum ternary alloy, and cannot meet the requirements of semiconductor chips. The target material obtained by the ternary alloy is prone to the problem of excessive oxide particles during sputtering coating, which leads to a decrease in the chip qualification rate. In addition, due to the addition of high-purity manganese, the production cost is high and the production capacity is limited.

[0007] In summary, providing a method for preparing a copper-manganese-aluminum ternary alloy ingot is a technical problem that needs to be solved in the current field. Summary of the invention

[0008] In view of the above problems, the purpose of the present invention is to provide a method for preparing a copper-manganese-aluminum ternary alloy ingot. Compared with the prior art, the preparation method provided by the present invention can reduce the oxygen content in the copper-manganese-aluminum ternary alloy, thereby reducing the problem of particles generated by the ternary alloy target during sputtering, and at the same time reducing the production cost.

[0009] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0010] The present invention provides a method for preparing a copper-manganese-aluminum ternary alloy ingot, the preparation method comprising the following steps:

[0011] (1) subjecting the copper raw material to a first vacuum induction melting to obtain molten copper liquid;

[0012] (2) adding aluminum raw material to the copper liquid obtained in step (1), and then allowing the mixture to stand to obtain a first mixed molten liquid;

[0013] (3) adding a manganese raw material to the first mixed molten liquid obtained in step (2), and then performing a second vacuum induction melting to obtain a second mixed molten liquid;

[0014] (4) casting and cooling the second mixed molten liquid obtained in step (3) to obtain a copper-manganese-aluminum ternary alloy ingot;

[0015] The weight percentage of aluminum in the copper-manganese-aluminum ternary alloy ingot is 0.01-0.1%, and the weight percentage of manganese is 0.05-0.2%.

[0016] In the copper-manganese-aluminum ternary alloy ingot provided by the present invention, by accurately controlling the content of aluminum and manganese, the generation of oxide particles can be reduced, while the production cost can be reduced, and the qualified rate in the subsequent target sputtering process can be improved. In addition, the copper-manganese-aluminum ternary alloy ingot provided by the present invention has good mechanical properties, the addition of manganese can improve the strength of the alloy, and the addition of aluminum can enhance the ductility of the copper alloy, which plays an important role in the subsequent production of thin film materials in electronic components and semiconductor devices.

[0017] Compared with the copper-aluminum alloy (generally the weight percentage of aluminum is 0.1-1%) commonly used in the prior art, the copper-manganese-aluminum ternary alloy ingot provided by the present invention controls the addition amount of aluminum to be 0.01-0.1%, for example, it can be 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09% or 0.1%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable. The risk of introducing oxides can be reduced by controlling the aluminum content, and the alloy target can be prevented from being generated during sputtering. The problem of too many particles; compared with the copper-manganese alloy commonly used in the prior art (generally the weight percentage of manganese is 0.2-2.0%), the copper-manganese-aluminum ternary alloy ingot provided by the present invention controls the addition amount of manganese to 0.05-0.2%, for example, it can be 0.05%, 0.06%, 0.08%, 0.10%, 0.12%, 0.14%, 0.16%, 0.18% or 0.20%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable, which can reduce the amount of high-purity manganese used, reduce production costs, and alleviate the problem of tight supply.

[0018] In the present invention, the copper-manganese-aluminum ternary alloy ingot has a purity of ≥99.9999% under optimal conditions, and can be used as a raw material for ultra-high purity copper-manganese-aluminum ternary alloy target material for magnetron sputtering preparation of thin films.

[0019] Preferably, the copper raw material in step (1) comprises electrolytic copper.

[0020] Preferably, the purity of the copper raw material is ≥99.9999%, for example, it can be 99.99991%, 99.99992%, 99.99993%, 99.99994% or 99.99995%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0021] In the present invention, by preferably using electrolytic copper with a purity of 99.9999% or more, the purity of the ternary alloy can be further guaranteed, thereby avoiding the problem of particles generated by the alloy target during sputtering.

[0022] Preferably, in step (1), vacuuming is performed before the first vacuum induction melting.

[0023] Preferably, the vacuum degree during evacuation is ≤0.01 Pa, for example, 0.01 Pa, 0.009 Pa or 0.008 Pa, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0024] In the present invention, by preferably controlling the vacuum degree at the end point of vacuuming, the oxygen content can be further reduced. The reduction of the oxygen content helps to reduce the generation of oxides and reduce the risk of introducing oxides into the alloy.

[0025] Preferably, the temperature of the first vacuum induction melting in step (1) is 1250-1350°C, for example, 1250°C, 1260°C, 1270°C, 1280°C, 1290°C, 1300°C, 1310°C, 1320°C, 1340°C or 1350°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0026] Preferably, the time for the first vacuum induction melting is 20-40 min, for example, 20 min, 22 min, 24 min, 26 min, 28 min, 30 min, 32 min, 34 min, 36 min, 38 min or 40 min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0027] Preferably, the purity of the aluminum raw material in step (2) is ≥99.9995%, for example, it can be 99.9995%, 99.9996%, 99.9997%, 99.9998% or 99.9999%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0028] Preferably, the aluminum raw material in step (2) is pickled before being added.

[0029] Preferably, the acid solution used in the pickling treatment includes dilute nitric acid.

[0030] Preferably, the mass concentration of the dilute nitric acid is 14-18%, for example, it can be 14%, 14.5%, 15%, 15.5%, 16%, 16.5%, 17% or 18%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0031] In the present invention, by preferably performing pickling treatment on the aluminum raw material, impurities and oxide layers on the aluminum surface can be removed, thereby avoiding the introduction of oxides into the ingot and ensuring the purity of the ingot.

[0032] Preferably, the standing time in step (2) is 20-40 min, for example, it can be 20 min, 22 min, 24 min, 26 min, 30 min, 32 min, 34 min, 36 min, 38 min or 40 min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0033] In the present invention, by preferably controlling the standing time, inclusions and slag in the molten metal can be sufficiently precipitated and separated, thereby reducing the formation of oxidized slag.

[0034] Preferably, the purity of the manganese raw material in step (3) is ≥99.999%, for example, it can be 99.999%, 99.9991%, 99.9992%, 99.9993% or 99.9994%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0035] In the present invention, by preferably controlling the purity of the manganese raw material, the risk of impurities formed during the preparation process can be reduced, the purity of the ingot can be further guaranteed, and the particle problem of the alloy target during the sputtering process can be reduced.

[0036] Preferably, the temperature of the second vacuum induction melting in step (3) is 1350-1450°C, for example, 1350°C, 1360°C, 1370°C, 1380°C, 1390°C, 1400°C, 1410°C, 1420°C, 1430°C, 1440°C or 1450°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0037] Preferably, the time for the second vacuum induction melting is 110-130 min, for example, 110 min, 112 min, 114 min, 116 min, 120 min, 122 min, 124 min, 126 min, 128 min or 130 min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0038] As a preferred technical solution of the present invention, the preparation method comprises the following steps:

[0039] (1) vacuuming a copper raw material with a purity of ≥99.9999% to an end point vacuum degree of ≤0.01 Pa, and then performing a first vacuum induction melting at a temperature of 1250-1350° C. for 20-40 min to obtain molten copper liquid;

[0040] (2) adding an aluminum raw material with a purity of ≥99.9995% to the copper liquid obtained in step (1), wherein the aluminum raw material is pickled with a dilute nitric acid solution with a mass concentration of 14-18% before being added, and then allowed to stand for 20-40 minutes to obtain a first mixed molten liquid;

[0041] (3) adding a manganese raw material with a purity of ≥99.999% to the first mixed molten liquid obtained in step (2), and then performing a second vacuum induction melting at a temperature of 1350-1450° C. for 110-130 min to obtain a second mixed molten liquid;

[0042] (4) The second mixed molten liquid obtained in step (3) is cast and cooled in sequence to obtain a copper-manganese-aluminum ternary alloy ingot, wherein the weight percentage of aluminum in the copper-manganese-aluminum ternary alloy ingot is 0.01-0.1%, and the weight percentage of manganese in the copper-manganese-aluminum ternary alloy ingot is 0.05-0.2%.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] In the preparation method of the copper-manganese-aluminum ternary alloy ingot provided by the present invention, by accurately controlling the content of aluminum and manganese, the generation of oxide particles can be reduced while reducing production costs. Under optimal conditions, the oxygen content of the copper-manganese-aluminum ternary alloy ingot can be made to be less than 1ppm, meeting the use requirements of ultra-high purity copper-manganese-aluminum ternary alloy targets, and improving the pass rate in the subsequent target sputtering process. In addition, the copper-manganese-aluminum ternary alloy ingot provided by the present invention has good mechanical properties, the addition of manganese can improve the strength of the alloy, and the addition of aluminum can enhance the ductility of the copper alloy, which plays an important role in the subsequent production of thin film materials in electronic components and semiconductor devices. DETAILED DESCRIPTION

[0045] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0046] Example 1

[0047] This embodiment provides a method for preparing a copper-manganese-aluminum ternary alloy ingot, the preparation method comprising the following steps:

[0048] (1) evacuating a copper raw material with a purity of 99.9999% to an end point vacuum degree of 0.01 Pa, and then performing a first vacuum induction melting at a temperature of 1300° C. for 30 min to obtain a molten copper liquid;

[0049] (2) adding an aluminum raw material with a purity of 99.9995% to the copper liquid obtained in step (1), wherein the aluminum raw material is pickled with a dilute nitric acid solution with a mass concentration of 16% before being added, and then standing for 30 minutes to obtain a first mixed molten liquid;

[0050] (3) adding a manganese raw material with a purity of 99.999% to the first mixed molten liquid obtained in step (2), and then performing a second vacuum induction melting for 120 minutes at a temperature of 1400° C. to obtain a second mixed molten liquid;

[0051] (4) The second mixed molten liquid obtained in step (3) is cast and cooled in sequence to obtain a copper-manganese-aluminum ternary alloy ingot, wherein the weight percentage of aluminum in the copper-manganese-aluminum ternary alloy ingot is 0.05%, and the weight percentage of manganese in the copper-manganese-aluminum ternary alloy ingot is 0.1%.

[0052] Example 2

[0053] This embodiment provides a method for preparing a copper-manganese-aluminum ternary alloy ingot, the preparation method comprising the following steps:

[0054] (1) evacuating a copper raw material with a purity of 99.9999% to an end point vacuum degree of 0.008 Pa, and then performing a first vacuum induction melting at a temperature of 1250° C. for 40 min to obtain molten copper liquid;

[0055] (2) adding an aluminum raw material with a purity of 99.9995% to the copper liquid obtained in step (1), wherein the aluminum raw material is pickled with a dilute nitric acid solution with a mass concentration of 14% before being added, and then allowed to stand for 20 minutes to obtain a first mixed molten liquid;

[0056] (3) adding a manganese raw material with a purity of 99.999% to the first mixed molten liquid obtained in step (2), and then performing a second vacuum induction melting at a temperature of 1450° C. for 110 min to obtain a second mixed molten liquid;

[0057] (4) The second mixed molten liquid obtained in step (3) is cast and cooled in sequence to obtain a copper-manganese-aluminum ternary alloy ingot, wherein the weight percentage of aluminum in the copper-manganese-aluminum ternary alloy ingot is 0.1%, and the weight percentage of manganese in the copper-manganese-aluminum ternary alloy ingot is 0.05%.

[0058] Example 3

[0059] This embodiment provides a method for preparing a copper-manganese-aluminum ternary alloy ingot, the preparation method comprising the following steps:

[0060] (1) evacuating a copper raw material with a purity of 99.9999% to an end point vacuum degree of 0.005 Pa, and then performing a first vacuum induction melting at a temperature of 1350° C. for 20 min to obtain a molten copper liquid;

[0061] (2) adding an aluminum raw material with a purity of 99.9995% to the copper liquid obtained in step (1), wherein the aluminum raw material is pickled with a dilute nitric acid solution with a mass concentration of 18% before being added, and then allowed to stand for 40 minutes to obtain a first mixed molten liquid;

[0062] (3) adding a manganese raw material with a purity of 99.999% to the first mixed molten liquid obtained in step (2), and then performing a second vacuum induction melting at a temperature of 1350° C. for 130 min to obtain a second mixed molten liquid;

[0063] (4) The second mixed molten liquid obtained in step (3) is cast and cooled in sequence to obtain a copper-manganese-aluminum ternary alloy ingot, wherein the weight percentage of aluminum in the copper-manganese-aluminum ternary alloy ingot is 0.01%, and the weight percentage of manganese in the copper-manganese-aluminum ternary alloy ingot is 0.2%.

[0064] Example 4

[0065] This embodiment provides a method for preparing a copper-manganese-aluminum ternary alloy ingot. The difference between the preparation method and Example 1 is that the temperature of the first vacuum induction melting is 1200°C.

[0066] Example 5

[0067] This embodiment provides a method for preparing a copper-manganese-aluminum ternary alloy ingot. The difference between the preparation method and Example 1 is that the temperature of the first vacuum induction melting is 1400°C.

[0068] Example 6

[0069] This embodiment provides a method for preparing a copper-manganese-aluminum ternary alloy ingot. The difference between the preparation method and Example 1 is that the ingot is left to stand for 10 minutes.

[0070] Example 7

[0071] This embodiment provides a method for preparing a copper-manganese-aluminum ternary alloy ingot. The difference between the preparation method and embodiment 1 is that the final vacuum degree of the vacuum pumping is 0.5Pa.

[0072] Example 8

[0073] This embodiment provides a method for preparing a copper-manganese-aluminum ternary alloy ingot. The difference between the preparation method and Example 1 is that the temperature of the second vacuum induction melting is 1300°C.

[0074] Comparative Example 1

[0075] This comparative example provides a method for preparing a copper-manganese-aluminum ternary alloy ingot. The difference between the preparation method and Example 1 is that the weight percentage of manganese remains unchanged, and only the weight percentages of copper and aluminum are changed to make the weight percentage of aluminum 0.5%.

[0076] The oxygen content of the copper-manganese-aluminum ternary alloy ingots prepared in Examples 1-8 and Comparative Example 1 was detected using a LECO oxygen content detector. The results are shown in Table 1.

[0077] Table 1

[0078] Oxygen content / ppm Example 1 1 Example 2 1 Example 3 1 Example 4 1.2 Example 5 1.2 Example 6 1.5 Example 7 1.9 Example 8 1.5 Comparative Example 1 3

[0079] From the data in Table 1, we can see the following points:

[0080] (1) It can be seen from the data of Examples 1-3 that, under optimal conditions, the preparation method provided by the present invention can make the oxygen content of the copper-manganese-aluminum ternary alloy ingot reach less than 1 ppm, meet the use requirements of ultra-high purity copper-manganese-aluminum ternary alloy target materials, and reduce the risk of particle generation during the sputtering process.

[0081] (2) A comprehensive comparison of the data of Example 1 and Examples 4-5 shows that the temperature of the first vacuum induction melting in Example 4 is too low, resulting in insufficient degassing and inability to effectively remove oxygen from the melt, while the temperature of the first vacuum induction melting in Example 5 is too high, resulting in more volatilization of the copper liquid and more burnout of Al, which also leads to an increase in the oxygen content. It can be seen that the present invention can further reduce the oxygen content of the copper-manganese-aluminum ternary alloy ingot by optimally controlling the temperature of the first vacuum induction melting.

[0082] (3) A comprehensive comparison of the data of Example 1 and Example 6 shows that the only difference between Example 6 and Example 1 is that the standing time is too short, resulting in the inability to effectively remove inclusions, thereby causing an increase in the oxygen content, while the standing time is too long, which will lead to a large burnout of Al and Mn. Therefore, the present invention can further reduce the oxygen content of the ingot by optimally controlling the standing time.

[0083] (4) A comprehensive comparison of the data of Example 1 and Example 7 shows that the only difference between Example 7 and Example 1 is that the terminal vacuum degree of vacuum extraction is not within the preferred range of the present invention, which makes it easy for ambient oxygen to be introduced into the ingot during the smelting process. It can be seen that the present invention can further reduce the oxygen content of the ingot by preferably controlling the terminal vacuum degree of vacuum extraction.

[0084] (5) A comprehensive comparison of the data of Example 1 and Example 8 shows that the temperature of the second vacuum induction melting in Example 8 is too low, resulting in incomplete deoxidation and a high oxygen content. If the temperature of the second vacuum induction melting is too high, it will cause a large burnout of Al and Mn. It can be seen that the present invention can further control the oxygen content in the ingot by optimally controlling the temperature of the second vacuum induction melting.

[0085] (6) Comprehensively comparing the data of Example 1 and Comparative Example 1, it can be seen that the difference between Comparative Example 1 and Example 1 is that the Al content is too high, resulting in more oxides produced by Al combining with oxygen during the smelting process. In addition, when the manganese content is too high, it is easy to cause excessively high production costs. When the Al and Mn contents are too low, the performance of the alloy cannot meet the requirements of the target material. It can be seen that the present invention can reduce the oxygen content in the alloy and reduce the production cost by controlling the mass percentage of Al and Mn in the copper-manganese-aluminum ternary alloy ingot.

[0086] In summary, the preparation method provided by the present invention can reduce the oxygen content in the copper-manganese-aluminum ternary alloy, thereby reducing the problem of particles generated by the ternary alloy target during sputtering, while reducing the production cost and meeting the use requirements of the copper-manganese-aluminum ternary alloy target.

[0087] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a copper-manganese-aluminum ternary alloy ingot, characterized in that: The preparation method comprises the following steps: (1) subjecting the copper raw material to a first vacuum induction melting to obtain molten copper liquid; (2) adding aluminum raw material to the copper liquid obtained in step (1), and then allowing the mixture to stand to obtain a first mixed molten liquid; (3) adding a manganese raw material to the first mixed molten liquid obtained in step (2), and then performing a second vacuum induction melting to obtain a second mixed molten liquid; (4) casting and cooling the second mixed molten liquid obtained in step (3) to obtain a copper-manganese-aluminum ternary alloy ingot; The weight percentage of aluminum in the copper-manganese-aluminum ternary alloy ingot is 0.01-0.1%, and the weight percentage of manganese is 0.05-0.2%.

2. The preparation method according to claim 1, characterized in that: The copper raw material in step (1) includes electrolytic copper; Preferably, the purity of the copper raw material is ≥99.9999%.

3. The preparation method according to claim 1 or 2, characterized in that: Step (1) before the first vacuum induction melting, vacuuming is performed; Preferably, the vacuum is evacuated to an end point with a vacuum degree of ≤0.01 Pa.

4. The preparation method according to any one of claims 1 to 3, characterized in that Step (1) The temperature of the first vacuum induction melting is 1250-1350° C.; Preferably, the first vacuum induction melting time is 20-40 minutes.

5. The preparation method according to any one of claims 1 to 4, characterized in that: The purity of the aluminum raw material in step (2) is ≥99.9995%.

6. The preparation method according to any one of claims 1 to 5, characterized in that: The aluminum raw material in step (2) is pickled before being added; Preferably, the acid solution used in the pickling treatment includes dilute nitric acid; Preferably, the mass concentration of the dilute nitric acid is 14-18%.

7. The preparation method according to any one of claims 1 to 6, characterized in that: The standing time in step (2) is 20-40 minutes.

8. The preparation method according to any one of claims 1 to 7, characterized in that: The purity of the manganese raw material in step (3) is ≥99.999%.

9. The preparation method according to any one of claims 1 to 8, characterized in that: Step (3) The temperature of the second vacuum induction melting is 1350-1450° C.; Preferably, the second vacuum induction melting time is 110-130 minutes.

10. The preparation method according to any one of claims 1 to 9, characterized in that: The preparation method comprises the following steps: (1) vacuuming a copper raw material with a purity of ≥99.9999% to an end point vacuum degree of ≤0.01 Pa, and then performing a first vacuum induction melting at a temperature of 1250-1350° C. for 20-40 min to obtain molten copper liquid; (2) adding an aluminum raw material with a purity of ≥99.9995% to the copper liquid obtained in step (1), wherein the aluminum raw material is pickled with a dilute nitric acid solution with a mass concentration of 14-18% before being added, and then allowed to stand for 20-40 minutes to obtain a first mixed molten liquid; (3) adding a manganese raw material with a purity of ≥99.999% to the first mixed molten liquid obtained in step (2), and then performing a second vacuum induction melting at a temperature of 1350-1450° C. for 110-130 min to obtain a second mixed molten liquid; (4) The second mixed molten liquid obtained in step (3) is cast and cooled in sequence to obtain a copper-manganese-aluminum ternary alloy ingot, wherein the weight percentage of aluminum in the copper-manganese-aluminum ternary alloy ingot is 0.01-0.1%, and the weight percentage of manganese in the copper-manganese-aluminum ternary alloy ingot is 0.05-0.2%.