A method for preparing a copper-manganese-aluminum ternary alloy ingot

Abstract

The application relates to a preparation method of a copper-manganese-aluminum ternary alloy ingot, and the preparation method comprises the following steps: first vacuum induction smelting a copper raw material to obtain molten copper liquid; adding aluminum raw material into the copper liquid and then standing to obtain a first mixed smelting liquid; adding manganese raw material into the first mixed smelting liquid and then performing second vacuum induction smelting to obtain a second mixed smelting liquid; sequentially performing casting forming and cooling on the second mixed smelting liquid to obtain the copper-manganese-aluminum ternary alloy ingot; the weight percentage content of aluminum in the copper-manganese-aluminum ternary alloy ingot is 0.01-0.1%, and the weight percentage content of manganese is 0.05-0.2%. The preparation method can reduce the oxygen content in the copper-manganese-aluminum ternary alloy, thereby reducing the problem that particles are generated when the ternary alloy target material is sputtered, and the production cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of alloy smelting technology, specifically to a method for preparing copper-manganese-aluminum ternary alloy ingots. Background Technology

[0002] Ultra-high purity (≥99.9999%) copper and its alloys (such as copper-aluminum and copper-manganese) are key materials for integrated circuit chips. With the continuous advancement of integrated circuit technology, the applications of copper-aluminum and copper-manganese alloys are becoming increasingly widespread. Adding aluminum or manganese can significantly improve the physical properties of copper alloys.

[0003] However, the high reactivity of aluminum makes it prone to introducing oxygen impurities during the production of copper-aluminum alloys. This can lead to the formation of oxide particles during sputtering, increasing the chip scrap rate. While copper-manganese alloys use high-purity manganese that is less prone to oxidation, their higher cost makes them more expensive, thus increasing the overall manufacturing cost of the chips.

[0004] CN111197129A discloses a copper-aluminum-manganese alloy and its preparation method. The copper-aluminum-manganese alloy contains chemical elements in the following mass fraction ratio: Al: 9.5-10.5%, Mn: 11.5-12.5%, with the balance being Cu. The metallographic structure of the copper-aluminum-manganese alloy includes a metastable β-phase structure and an intracrystalline dispersed α-phase. It is mainly used in applications requiring high strength and plasticity, such as heavy-duty bearing bushes, wear-resistant and pressure-resistant valve bodies in high-temperature chemical equipment, and elastic structural components in nuclear reactor peripheral equipment.

[0005] CN114318023A discloses a vacuum smelting method for a high-alumina manganese copper alloy. The method steps are as follows: (1) copper, nickel, and cobalt are placed in the crucible of an induction melting furnace; (2) the induction melting furnace is evacuated and then heated by electricity; when the furnace charge begins to melt, argon gas is introduced into the induction melting furnace for protection; (3) after the furnace charge is melted, some aluminum particles are added, and the aluminum particles melt and form a thin film on the liquid surface; then electrolytic manganese is added; after the electrolytic manganese is melted, the remaining aluminum particles are added; until all is melted; (4) the melted material is cast into a water-cooled ingot mold and cooled with the furnace.

[0006] However, the above method is not applicable to the preparation of ultra-high purity copper-manganese-aluminum ternary alloys, which cannot meet the requirements of semiconductor chips. The target material obtained by this ternary alloy is prone to excessive oxide particles during sputtering coating, which leads to a decrease in the yield of chips. Furthermore, the addition of high-purity manganese results in higher production costs and limited production capacity.

[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 this field. Summary of the Invention

[0008] To address the above problems, the present invention aims to provide a method for preparing copper-manganese-aluminum ternary alloy ingots. 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 particle generation in the ternary alloy target during sputtering, and at the same time reducing production costs.

[0009] To achieve this objective, the present invention employs the following technical solution:

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

[0011] (1) The copper raw material is subjected to a first vacuum induction melting process to obtain molten copper liquid;

[0012] (2) Add aluminum raw material to the copper liquid obtained in step (1), and then let it stand to obtain the first mixed smelting liquid;

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

[0014] (4) The second mixed molten liquid obtained in step (3) is successively cast and cooled to obtain a copper-manganese-aluminum ternary alloy ingot;

[0015] The copper-manganese-aluminum ternary alloy ingot contains 0.01-0.1% aluminum by weight and 0.05-0.2% manganese by weight.

[0016] The copper-manganese-aluminum ternary alloy ingot provided by this invention, through precise control of the aluminum and manganese content, can reduce the generation of oxide particles, lower production costs, and improve the yield rate in the subsequent target sputtering process. Furthermore, the copper-manganese-aluminum ternary alloy ingot provided by this invention possesses excellent mechanical properties; the addition of manganese can improve the alloy's strength, while the addition of aluminum can enhance the ductility of the copper alloy, playing a crucial role in the subsequent production of thin film materials for electronic components and semiconductor devices.

[0017] Compared to commonly used copper-aluminum alloys (generally with an aluminum weight percentage of 0.1-1%) in the prior art, the copper-manganese-aluminum ternary alloy ingot provided by this invention, by controlling the aluminum content to 0.01-0.1%, for example, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, or 0.1%, but not limited to the listed values, other unlisted values ​​within the range are also applicable. This reduces the risk of introducing oxides and avoids the formation of oxides in the alloy target during sputtering. The problem of excessive particle content: 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 this invention can reduce the amount of high-purity manganese used, reduce production costs, and alleviate the supply shortage problem by controlling the amount of manganese added to 0.05-0.2%, for example, 0.05%, 0.06%, 0.08%, 0.10%, 0.12%, 0.14%, 0.16%, 0.18%, or 0.20%, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0018] In this 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 targets for magnetron sputtering to prepare thin films.

[0019] Preferably, the copper raw material in step (1) includes 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. Other unlisted values ​​within the range are also applicable.

[0021] In this invention, by preferably using electrolytic copper with a purity of 99.9999% or higher, the purity of the ternary alloy can be further guaranteed, and the problem of particles being generated in the alloy target during sputtering can be avoided.

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

[0023] Preferably, the vacuum level at the end point of evacuation is ≤0.01Pa, for example, it can be 0.01Pa, 0.009Pa or 0.008Pa, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0024] In this invention, by optimally controlling the final vacuum level of the vacuum pump, the oxygen content can be further reduced. The reduction in oxygen content helps to reduce the formation of oxides and lower the risk of introducing oxides into the alloy.

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

[0026] Preferably, the first vacuum induction melting time is 20-40 min, for example, it can be 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 unlisted values ​​within the 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. Other unlisted values ​​within the 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. Other unlisted values ​​within the range are also applicable.

[0031] In this invention, by preferably acid-washing the aluminum raw material, impurities and oxide layers on the aluminum surface can be removed, avoiding the introduction of oxides into the ingot and ensuring the purity of the ingot.

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

[0033] In this invention, by optimally controlling the settling time, inclusions and slag in the molten liquid can be fully precipitated and separated, reducing the formation of oxide inclusions.

[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. Other unlisted values ​​within the range are also applicable.

[0035] In this invention, by optimizing the control of the purity of manganese raw materials, the risk of impurities forming during the preparation process can be reduced, further ensuring the purity of the ingot and reducing particle problems in the alloy target material during sputtering.

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

[0037] Preferably, the second vacuum induction melting time is 110-130 min, for example, it can be 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 unlisted values ​​within the range are also applicable.

[0038] As a preferred embodiment of the present invention, the preparation method includes the following steps:

[0039] (1) Vacuum the copper raw material with a purity of ≥99.9999% until the final vacuum degree is ≤0.01Pa, and then perform the first vacuum induction melting for 20-40 minutes at a temperature of 1250-1350℃ to obtain molten copper liquid.

[0040] (2) Add aluminum raw material with a purity of ≥99.9995% to the copper liquid obtained in step (1). Before adding the aluminum raw material, it is pickled with dilute nitric acid solution with a mass concentration of 14-18%, and then left to stand for 20-40 minutes to obtain the first mixed smelting liquid.

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

[0042] (4) The second mixed molten liquid obtained in step (3) is sequentially cast and cooled 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 is 0.05-0.2%.

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

[0044] The method for preparing copper-manganese-aluminum ternary alloy ingots provided by this invention, by precisely controlling the content of aluminum and manganese, can reduce the generation of oxide particles and lower production costs. Under optimal conditions, the oxygen content of the copper-manganese-aluminum ternary alloy ingot can reach below 1 ppm, meeting the requirements for ultra-high purity copper-manganese-aluminum ternary alloy targets and improving the yield rate in subsequent target sputtering processes. Furthermore, the copper-manganese-aluminum ternary alloy ingots provided by this invention possess excellent mechanical properties. The addition of manganese can improve the strength of the alloy, while the addition of aluminum can enhance the ductility of the copper alloy, playing a crucial role in the subsequent production of thin film materials for electronic components and semiconductor devices. Detailed Implementation

[0045] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0046] Example 1

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

[0048] (1) The copper raw material with a purity of 99.9999% was evacuated to a final vacuum degree of 0.01 Pa, and then the first vacuum induction melting was carried out at a temperature of 1300℃ for 30 min to obtain molten copper liquid.

[0049] (2) Add aluminum raw material with a purity of 99.9995% to the copper liquid obtained in step (1). Before adding the aluminum raw material, it is pickled with dilute nitric acid solution with a mass concentration of 16%, and then left to stand for 30 minutes to obtain the first mixed smelting liquid.

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

[0051] (4) The second mixed molten liquid obtained in step (3) is sequentially cast and cooled 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 is 0.1%.

[0052] Example 2

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

[0054] (1) The copper raw material with a purity of 99.9999% was evacuated to a final vacuum degree of 0.008 Pa, and then the first vacuum induction melting was carried out at a temperature of 1250℃ for 40 min to obtain molten copper liquid.

[0055] (2) Add aluminum raw material with a purity of 99.9995% to the copper liquid obtained in step (1). Before adding the aluminum raw material, it is pickled with dilute nitric acid solution with a mass concentration of 14% and then left to stand for 20 minutes to obtain the first mixed smelting liquid.

[0056] (3) Add manganese raw material with a purity of 99.999% to the first mixed molten liquid obtained in step (2), and then perform a second vacuum induction melting at a temperature of 1450℃ for 110 minutes to obtain a second mixed molten liquid.

[0057] (4) The second mixed molten liquid obtained in step (3) is sequentially cast and cooled 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 is 0.05%.

[0058] Example 3

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

[0060] (1) The copper raw material with a purity of 99.9999% was evacuated to a final vacuum degree of 0.005 Pa, and then the first vacuum induction melting was carried out at a temperature of 1350℃ for 20 min to obtain molten copper liquid.

[0061] (2) Add aluminum raw material with a purity of 99.9995% to the copper liquid obtained in step (1). Before adding the aluminum raw material, it is pickled with dilute nitric acid solution with a mass concentration of 18% and then left to stand for 40 minutes to obtain the first mixed smelting liquid.

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

[0063] (4) The second mixed molten liquid obtained in step (3) is sequentially cast and cooled 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 is 0.2%.

[0064] Example 4

[0065] This embodiment provides a method for preparing a copper-manganese-aluminum ternary alloy ingot. The only difference between this method and that of Embodiment 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 only difference between this method and that of Embodiment 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 only difference between this method and that of Embodiment 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 only difference between this method and Example 1 is that the final vacuum level after evacuation is 0.5 Pa.

[0072] Example 8

[0073] This embodiment provides a method for preparing a copper-manganese-aluminum ternary alloy ingot. The only difference between this method and that of Embodiment 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 this method and Example 1 is that the weight percentage of manganese remains unchanged, and only the weight percentages of copper and aluminum are changed so that the weight percentage of aluminum is 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 analyzer, and 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] The following points can be observed from the data in Table 1:

[0080] (1) As can be seen from the data of Examples 1-3, the preparation method provided by the present invention can achieve an oxygen content of less than 1 ppm in copper-manganese-aluminum ternary alloy ingots under better conditions, which meets the requirements for use of ultra-high purity copper-manganese-aluminum ternary alloy targets and can reduce the risk of generating particles during sputtering.

[0081] (2) By comparing the data of Example 1 and Examples 4-5, it can be seen that the temperature of the first vacuum induction melting in Example 4 was too low, resulting in insufficient degassing and inability to effectively remove oxygen from the melt. In Example 5, the temperature of the first vacuum induction melting was too high, resulting in more copper evaporation and more Al burn-off, which also led to an increase in oxygen content. Therefore, it can be seen that by optimally controlling the temperature of the first vacuum induction melting, the present invention can further reduce the oxygen content of copper-manganese-aluminum ternary alloy ingots.

[0082] (3) Comparing the data of Example 1 and Example 6, it can be seen that the difference between Example 6 and Example 1 is that the standing time is too short, which leads to the inability to effectively remove inclusions, resulting in an increase in oxygen content. However, if the standing time is too long, it will lead to greater burn-off of Al and Mn. Therefore, the present invention can further reduce the oxygen content of the ingot by optimizing the standing time.

[0083] (4) A comprehensive comparison of the data of Example 1 and Example 7 shows that the difference between Example 7 and Example 1 is that the final vacuum degree of the vacuuming 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. Therefore, the present invention can further reduce the oxygen content of the ingot by preferentially controlling the final vacuum degree of the vacuuming.

[0084] (5) Comparing the data of Example 1 and Example 8, it can be seen that the temperature of the second vacuum induction melting in Example 8 is too low, resulting in incomplete deoxidation and high oxygen content. If the temperature of the second vacuum induction melting is too high, it will lead to greater loss of Al and Mn. Therefore, 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) A comprehensive comparison of the data from Example 1 and Comparative Example 1 shows that the difference between Comparative Example 1 and Example 1 lies in the excessively high Al content, which leads to more oxides produced by Al combining with oxygen during the smelting process. Furthermore, excessively high manganese content can easily result in excessively high production costs, while excessively low Al and Mn content prevents the alloy from meeting the requirements of the target material. Therefore, this invention, by controlling the mass percentage of Al and Mn in the copper-manganese-aluminum ternary alloy ingot, can reduce the oxygen content in the alloy while simultaneously reducing production costs.

[0086] In summary, the preparation method provided by this invention can reduce the oxygen content in the copper-manganese-aluminum ternary alloy, thereby reducing the problem of particle generation during sputtering of the ternary alloy target, while also reducing production costs and meeting the requirements for the use of copper-manganese-aluminum ternary alloy targets.

[0087] The applicant declares that the above description is only a specific embodiment 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 conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection 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 includes the following steps: (1) The copper raw material is evacuated to the final vacuum degree ≤0.01Pa, and then the first vacuum induction melting is carried out at a temperature of 1250-1350℃ to obtain molten copper liquid; (2) Add aluminum raw material to the copper liquid obtained in step (1), and then let it stand for 20-40 minutes to obtain the first mixed smelting liquid; (3) Add manganese raw material to the first mixed molten liquid obtained in step (2), and then perform a second vacuum induction melting at a temperature of 1350-1450℃ to obtain a second mixed molten liquid; (4) The second mixed molten liquid obtained in step (3) is sequentially cast and cooled to obtain a copper-manganese-aluminum ternary alloy ingot; The copper-manganese-aluminum ternary alloy ingot contains 0.01-0.09% aluminum by weight and 0.12-0.2% manganese by weight.

2. The preparation method according to claim 1, characterized in that, The copper raw material mentioned in step (1) includes electrolytic copper.

3. The preparation method according to claim 1, characterized in that, The purity of the copper raw material is ≥99.9999%.

4. The preparation method according to claim 1, characterized in that, The first vacuum induction melting time is 20-40 minutes.

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

6. The preparation method according to claim 1, characterized in that, The aluminum raw material described in step (2) is pickled before being added.

7. The preparation method according to claim 6, characterized in that, The acid solution used in the pickling process includes dilute nitric acid.

8. The preparation method according to claim 7, characterized in that, The mass concentration of the dilute nitric acid is 14-18%.

9. The preparation method according to claim 1, characterized in that, The purity of the manganese raw material in step (3) is ≥99.999%.

10. The preparation method according to claim 1, characterized in that, The second vacuum induction melting time is 110-130 min.

11. The preparation method according to claim 1, characterized in that, The preparation method includes the following steps: (1) Vacuum the copper raw material with a purity of ≥99.9999% until the final vacuum degree is ≤0.01Pa, and then perform the first vacuum induction melting for 20-40 minutes at a temperature of 1250-1350℃ to obtain molten copper liquid; (2) Add aluminum raw material with a purity of ≥99.9995% to the copper liquid obtained in step (1). Before adding the aluminum raw material, it is pickled with dilute nitric acid solution with a mass concentration of 14-18%, and then left to stand for 20-40 minutes to obtain the first mixed smelting liquid. (3) Add manganese raw material with a purity of ≥99.999% to the first mixed molten liquid obtained in step (2), and then perform a second vacuum induction melting for 110-130 min at a temperature of 1350-1450℃ to obtain a second mixed molten liquid; (4) The second mixed molten liquid obtained in step (3) is cast and cooled sequentially to obtain a copper-manganese-aluminum ternary alloy ingot. The weight percentage of aluminum in the copper-manganese-aluminum ternary alloy ingot is 0.01-0.09%, and the weight percentage of manganese is 0.12-0.2%.