Method for preparing tungsten-silicon target material based on plasma rotating electrode atomization method

Abstract

The invention relates to a method for preparing a tungsten-silicon target material based on a plasma rotating electrode atomization method, which comprises the following steps of: (1) carrying out vacuum suspension smelting on a tungsten-silicon raw material to obtain alloy liquid; (2) the alloy liquid obtained in the step (1) is subjected to pouring and ingot pulling in sequence, and a cast ingot is obtained; (3) grinding the cast ingot obtained in the step (2), and granulating by adopting a plasma rotating electrode atomization method to obtain tungsten-silicon alloy powder; and (4) the tungsten-silicon alloy powder obtained in the step (3) is subjected to hot pressed sintering, and the tungsten-silicon target material is obtained. According to the method, the oxygen content of the tungsten-silicon target material can be reduced, introduction of metal and non-metal impurities is avoided, and the compactness of the target material is improved.

Description

Technical Field

[0001] The invention relates to the technical field of powder metallurgy, and in particular to a method for preparing a tungsten silicon target material based on a plasma rotating electrode atomization method. Background Art

[0002] Tungsten silicon thin films are usually used as gate contact layers, barrier layers or adhesion layers in integrated circuits, especially in the storage field. At present, the commonly used thin film preparation methods mainly include physical vapor deposition (magnetron sputtering) and chemical vapor deposition (CVD). Among them, if the WF6 / SiH4 system is used when preparing tungsten silicon thin films by chemical vapor deposition, it is generally easy to cause fluorine and hydrogen elements to remain, the film is easy to fall off, and the gradient coverage is low. If the WF6 / SiH2Cl2 system is used, the equipment is easily corroded by chlorine due to the high operating temperature. Although the thin film sputtered by physical vapor deposition has the advantages of high purity, strong bonding and high density, the requirements for the sputtering source tungsten silicon target are relatively high. Generally, the tungsten silicon target is required to have high density (≥99.5%), high purity (≥99.999%) and low gas content (O≤500ppm).

[0003] However, as one of the raw materials for preparing tungsten silicon targets, the oxygen content of silicon powder on the market is generally ≥4500ppm, which cannot be used to prepare tungsten silicon targets. In addition, silicon easily reacts with oxygen at room temperature to form silicon monoxide, which will form silicon dioxide as the temperature rises, resulting in a high oxygen content in the tungsten silicon target, which directly affects the resistivity of the film.

[0004] For example, CN114535579A discloses a method for preparing high-purity silicon tungsten powder. The method uses high-purity tungsten powder and high-purity silicon powder as raw materials, mixes and sinters them at high temperature to obtain high-purity silicon tungsten powder agglomerates, and then performs gas decomposition treatment to obtain high-purity silicon tungsten powder with good dispersibility.

[0005] CN114293158A discloses a method for preparing a tungsten-silicon alloy target, comprising the following steps: (1) using silicon powder and tungsten powder as raw materials, vacuum heating the silicon powder, and then quenching it with water; (2) placing the water-quenched silicon powder in a ball mill for vacuum ball milling, and then vacuum drying; (3) adding the vacuum-dried silicon powder to a mixed solution of sulfuric acid and hydrochloric acid for ultrasonic treatment; then washing it with water, and placing it in a drying oven for vacuum drying; (4) vacuum ball milling the silicon powder and tungsten powder; (5) vacuum induction heating the tungsten-silicon powder; (6) ball milling the preliminarily alloyed tungsten-silicon powder; and (7) sintering, machining, and removing the carburized layer of the mixed powder to obtain the tungsten-silicon alloy target.

[0006] The above method not only has a complicated process flow, but also easily introduces elements and impurities such as oxygen, hydrogen, and chlorine during operation. Therefore, it is of great significance to provide a method for preparing a tungsten silicon target material that can reduce the impurity content, especially the oxygen content. Summary of the invention

[0007] In view of the above problems, the purpose of the present invention is to provide a method for preparing a tungsten silicon target material based on a plasma rotating electrode atomization method. Compared with the prior art, the method provided by the present invention can reduce the oxygen content of the tungsten silicon target material, avoid the introduction of metal and non-metallic impurities, and improve the density of the target material.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] The present invention provides a method for preparing a tungsten silicon target material based on a plasma rotating electrode atomization method, the method comprising the following steps:

[0010] (1) subjecting tungsten silicon raw materials to vacuum suspension melting to obtain alloy liquid;

[0011] (2) pouring and pulling the alloy liquid obtained in step (1) in sequence to obtain an ingot;

[0012] (3) grinding the ingot obtained in step (2), and then granulating it by plasma rotating electrode atomization method to obtain tungsten silicon alloy powder;

[0013] (4) hot pressing and sintering the tungsten-silicon alloy powder obtained in step (3) to obtain a tungsten-silicon target.

[0014] In the method provided by the present invention, on the one hand, vacuum suspension smelting is used to prevent the alloy liquid from contacting the crucible, thereby preventing it from being contaminated by metal or non-metal impurities. At the same time, during the smelting process, oxides (mainly including silicon dioxide) and metal impurities are volatilized to reduce the oxygen content in the alloy. At the same time, the present invention uses a plasma rotating electrode atomization granulation method to further avoid the introduction of impurities and reduce the oxygen content compared to the existing mechanical granulation. On the other hand, the present invention can control the forming of the ingot and improve the density by pulling the ingot and controlling the ingot pulling speed. At the same time, the shape of the ingot is controlled by grinding to make it better suitable for plasma rotating electrode atomization granulation, thereby improving the sphericity and particle size uniformity of the tungsten silicon alloy powder, and finally making the tungsten silicon target material have good density.

[0015] Preferably, the tungsten-silicon raw material in step (1) comprises mixed particles of silicon and tungsten or tungsten-silicon alloy particles.

[0016] Preferably, the particle size of the tungsten silicon raw material is 3-15 mm, for example, it can be 3 mm, 4 mm, 5 mm, 6 mm, 8 mm, 10 mm, 12 mm, 14 mm or 15 mm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0017] Preferably, the purity of the tungsten silicon raw material is ≥99.999%, for example, it can be 99.9991%, 99.9992% or 99.9993%, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0018] Preferably, the tungsten silicon raw material in step (1) is pretreated before vacuum suspension melting.

[0019] Preferably, the pretreatment method includes ultrasonic cleaning and vacuum packaging performed sequentially.

[0020] Preferably, the cleaning solution for ultrasonic cleaning comprises water.

[0021] Preferably, the ultrasonic cleaning time is 10-15 min, for example, 10 min, 11 min, 12 min, 13 min, 14 min or 15 min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0022] Preferably, the temperature of the vacuum suspension smelting in step (1) is 2300-2400°C, for example, it can be 2300°C, 2310°C, 2320°C, 2330°C, 2340°C, 2350°C, 2360°C, 2370°C, 2380°C, 2390°C or 2400°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0023] Preferably, the vacuum suspension melting time is 50-70 min, for example, it can be 50 min, 52 min, 54 min, 56 min, 58 min, 60 min, 62 min, 64 min, 66 min, 68 min or 70 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0024] In the present invention, the vacuum suspension smelting is generally performed by first evacuating the vacuum to 0.008Pa, and then introducing 0.1Pa of argon gas to wash the furnace. In the subsequent smelting process, argon gas is continuously introduced to maintain the level of 0.1Pa.

[0025] Preferably, the casting mold in step (2) comprises a graphite mold.

[0026] Preferably, the pulling speed is ≤15 mm / min, for example, it can be 15 mm / min, 14 mm / min, 12 mm / min, 10 mm / min, 8 mm / min, 6 mm / min, 4 mm / min or 2 mm / min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0027] In the present invention, by controlling the ingot pulling speed within a specific range, the forming of the ingot can be further controlled, the density thereof can be improved, and the generation of pores can be avoided.

[0028] Preferably, the mass percentage of silicon in the ingot is 28-30%, for example, it can be 28%, 28.2%, 28.4%, 28.6%, 28.8%, 29%, 29.2%, 29.4%, 29.6%, 29.8% or 30%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0029] Preferably, the grinding in step (3) includes: removing the carburized layer on the surface of the ingot by cylindrical grinding.

[0030] Preferably, the grinding wheel for the external cylindrical grinding comprises a diamond grinding wheel.

[0031] Preferably, the roundness of the ingot after grinding is 0.022-0.027 mm, for example, it can be 0.022 mm, 0.023 mm, 0.024 mm, 0.025 mm, 0.026 mm or 0.027 mm, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0032] In the present invention, the roundness of the ingot after grinding is preferably controlled within a specific range, so that it can be suitable for granulation by plasma rotating electrode atomization method, avoid equipment damage, and improve the sphericity and uniformity of the tungsten silicon alloy powder.

[0033] Preferably, the straightness of the ingot after grinding is 0.03-0.05 mm, for example, it can be 0.03 mm, 0.032 mm, 0.034 mm, 0.036 mm, 0.038 mm, 0.04 mm, 0.042 mm, 0.044 mm, 0.046 mm, 0.048 mm or 0.05 mm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0034] In the present invention, the straightness of the ingot after grinding is preferably controlled within a specific range, so that it can be suitable for granulation by plasma rotating electrode atomization method, avoid equipment damage, and improve the sphericity and uniformity of the tungsten silicon alloy powder.

[0035] Preferably, the rotation speed of the ingot during the granulation process in step (3) is 9000-11000 r / min, for example, it can be 9000 r / min, 9200 r / min, 9400 r / min, 9600 r / min, 9800 r / min, 10000 r / min, 10200 r / min, 10400 r / min, 10600 r / min, 10800 r / min or 11000 r / min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0036] In the present invention, it is preferred to control the rotation speed of the ingot within a specific range, which can further avoid equipment damage and improve the sphericity of the tungsten silicon alloy powder.

[0037] Preferably, the granulation is carried out under a protective atmosphere.

[0038] Preferably, the protective atmosphere comprises argon.

[0039] Preferably, the sphericity of the tungsten silicon alloy powder is ≥ 0.98, for example, it may be 0.98, 0.99 or 1, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0040] In the present invention, the sphericity of the tungsten silicon alloy powder is preferably controlled within a specific range, which can further promote the molding of the tungsten silicon target and improve the density of the tungsten silicon target.

[0041] Preferably, the particle size of the tungsten silicon alloy powder is 45-135μm, for example, it can be 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm, 95μm, 100μm, 105μm, 110μm, 115μm, 120μm or 135μm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0042] In the present invention, the particle size of the tungsten silicon alloy powder is preferably controlled within a specific range, which can further promote the molding of the tungsten silicon target and improve the density of the tungsten silicon target.

[0043] Preferably, the temperature of the hot pressing sintering in step (4) is 1300-1400°C, for example, it can be 1300°C, 1310°C, 1320°C, 1330°C, 1340°C, 1350°C, 1360°C, 1370°C, 1380°C, 1390°C or 1400°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0044] Preferably, the hot pressing sintering time in step (4) is 2.5-3.5 h, for example, it can be 2.5 h, 2.6 h, 2.7 h, 2.8 h, 2.9 h, 3 h, 3.1 h, 3.2 h, 3.3 h, 3.4 h or 3.5 h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0045] As a preferred technical solution of the present invention, the method comprises the following steps:

[0046] (1) ultrasonically cleaning the tungsten silicon raw material in water for 10-15 minutes, and then vacuum packaging to obtain a pretreated tungsten silicon raw material; removing the pretreated tungsten silicon raw material from the packaging, and then vacuum suspension melting at a temperature of 2300-2400° C. for 50-70 minutes to obtain an alloy liquid;

[0047] (2) pouring the alloy liquid obtained in step (1) into a graphite mold, and then pulling an ingot, controlling the pulling rate to be ≤15 mm / min, to obtain an ingot, wherein the mass percentage of silicon in the ingot is 28-30%;

[0048] (3) using a diamond grinding wheel to perform external cylindrical grinding on the ingot obtained in step (2) to remove the carburized layer on the surface, wherein the roundness of the ingot after external cylindrical grinding is 0.022-0.027 mm, and the straightness is 0.03-0.05 mm, and then using a plasma rotating electrode atomization method to perform granulation in an argon atmosphere, and controlling the rotation speed of the ingot during the granulation process to be 9000-11000 r / min to obtain a tungsten silicon alloy powder, wherein the sphericity of the tungsten silicon alloy powder is ≥0.98 and the particle size is 45-135 μm;

[0049] (4) The tungsten-silicon alloy powder obtained in step (3) is hot-pressed and sintered at 1300-1400° C. for 2.5-3.5 hours to obtain a tungsten-silicon target.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] (1) The preparation method provided by the present invention prevents the alloy liquid from being contaminated by metal or non-metal impurities through vacuum suspension smelting, and at the same time, volatilizes oxides and metal impurities during the smelting process to reduce the oxygen content in the alloy.

[0052] (2) The preparation method provided by the present invention can avoid the introduction of impurities by adopting the plasma rotating electrode atomization method for granulation, and at the same time improve the sphericity and particle size uniformity of the tungsten silicon alloy powder. The sphericity of the obtained tungsten silicon alloy powder is ≥0.98, the surface is smooth, and there is no hollow powder. It can not only further reduce the oxygen content of the tungsten silicon target material, but also help to improve the density of the tungsten silicon target material. The oxygen content of the tungsten silicon target material can reach below 300ppm and the density can reach above 99.85%. Under better conditions, the oxygen content reaches below 300ppm and the density reaches above 99.95%.

[0053] (3) In the present invention, by using ingot pulling and controlling the ingot pulling speed and using grinding and controlling the roundness and straightness after grinding, the sphericity and particle size uniformity of the tungsten silicon alloy powder can be further improved, and finally the tungsten silicon target material has good density. DETAILED DESCRIPTION

[0054] 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.

[0055] Example 1

[0056] This embodiment provides a method for preparing a tungsten silicon target material based on a plasma rotating electrode atomization method, the method comprising the following steps:

[0057] (1) ultrasonically cleaning a tungsten silicon raw material (tungsten silicon alloy particles with a particle size of 3-15 mm and a purity of 99.999%) in water for 12 minutes, and then vacuum packaging to obtain a pretreated tungsten silicon raw material; removing the packaging of the pretreated tungsten silicon raw material, and then vacuum suspension melting for 60 minutes at a temperature of 2350° C., before vacuum suspension melting, evacuating to 0.008 Pa, and then introducing 0.1 Pa of argon gas to wash the furnace, and continuously introducing argon gas to maintain a level of 0.1 Pa during the subsequent melting process to obtain an alloy liquid;

[0058] (2) pouring the alloy liquid obtained in step (1) into a graphite mold, and then pulling an ingot, controlling the pulling rate to be 8 mm / min, to obtain an ingot, wherein the mass percentage of silicon in the ingot is 29%;

[0059] (3) using a diamond grinding wheel to grind the ingot obtained in step (2) to remove the carburized layer on the surface, wherein the roundness of the ingot after the grinding is 0.025 mm and the straightness is 0.04 mm, and then granulating is performed in an argon atmosphere by a plasma rotating electrode atomization method, and the rotation speed of the ingot during the granulation process is controlled to be 12000 r / min to obtain a tungsten silicon alloy powder, wherein the sphericity of the tungsten silicon alloy powder is 0.99 and the particle size is 40-80 μm;

[0060] (4) The tungsten-silicon alloy powder obtained in step (3) is hot-pressed and sintered at 1350° C. for 3 hours to obtain a tungsten-silicon target.

[0061] Example 2

[0062] This embodiment provides a method for preparing a tungsten silicon target material based on a plasma rotating electrode atomization method, the method comprising the following steps:

[0063] (1) ultrasonically cleaning a tungsten silicon raw material (tungsten silicon alloy particles with a particle size of 3-15 mm and a purity of 99.999%) in water for 10 minutes, and then vacuum packaging to obtain a pretreated tungsten silicon raw material; removing the packaging of the pretreated tungsten silicon raw material, and then vacuum suspension melting at a temperature of 2400° C. for 50 minutes, wherein the vacuum is first evacuated to 0.008 Pa before the vacuum suspension melting, and then 0.1 Pa of argon is introduced to wash the furnace, and argon is continuously introduced to maintain a level of 0.1 Pa during the subsequent melting process to obtain an alloy liquid;

[0064] (2) pouring the alloy liquid obtained in step (1) into a graphite mold, and then pulling an ingot, controlling the pulling rate to be 12 mm / min, to obtain an ingot, wherein the mass percentage of silicon in the ingot is 28%;

[0065] (3) using a diamond grinding wheel to grind the ingot obtained in step (2) to remove the carburized layer on the surface, wherein the roundness of the ingot after the grinding is 0.024 mm and the straightness is 0.05 mm, and then granulating is performed in an argon atmosphere by a plasma rotating electrode atomization method, and the rotation speed of the ingot during the granulation process is controlled to be 9000 r / min to obtain a tungsten silicon alloy powder, wherein the sphericity of the tungsten silicon alloy powder is 0.95 and the particle size is 45-135 μm;

[0066] (4) The tungsten-silicon alloy powder obtained in step (3) is hot-pressed and sintered at 1350° C. for 3 hours to obtain a tungsten-silicon target.

[0067] Example 3

[0068] This embodiment provides a method for preparing a tungsten silicon target material based on a plasma rotating electrode atomization method, the method comprising the following steps:

[0069] (1) ultrasonically cleaning a tungsten silicon raw material (silicon powder with a particle size of 3-15 mm and a purity of 99.999% and tungsten powder with a particle size of 3-15 mm and a purity of 99.999%) in water for 15 minutes, and then vacuum packaging to obtain a pretreated tungsten silicon raw material; removing the pretreated tungsten silicon raw material from the packaging, and then vacuum suspension melting at a temperature of 2300° C. for 70 minutes, before the vacuum suspension melting, first evacuating to 0.008 Pa, and then introducing 0.1 Pa of argon gas to wash the furnace, and continuously introducing argon gas to maintain a level of 0.1 Pa during the subsequent melting process to obtain an alloy liquid;

[0070] (2) pouring the alloy liquid obtained in step (1) into a graphite mold, and then pulling an ingot, controlling the pulling rate to be 5 mm / min, to obtain an ingot, wherein the mass percentage of silicon in the ingot is 30%;

[0071] (3) using a diamond grinding wheel to grind the ingot obtained in step (2) to remove the carburized layer on the surface, wherein the roundness of the ingot after the grinding is 0.026 mm and the straightness is 0.03 mm, and then granulation is performed in an argon atmosphere by a plasma rotating electrode atomization method, and the rotation speed of the ingot during the granulation process is controlled to be 10000 r / min to obtain a tungsten silicon alloy powder, wherein the sphericity of the tungsten silicon alloy powder is 0.97 and the particle size is 45-105 μm;

[0072] (4) The tungsten-silicon alloy powder obtained in step (3) is hot-pressed and sintered at 1350° C. for 3 hours to obtain a tungsten-silicon target.

[0073] Example 4

[0074] This embodiment provides a method for preparing a tungsten silicon target material based on a plasma rotating electrode atomization method. The difference between the method and the embodiment 1 is that the rotation speed of the ingot during the granulation process is 8000 r / min.

[0075] Comparative Example 1

[0076] This comparative example provides a method for preparing a tungsten silicon target material. The only difference compared with Example 1 is that the plasma rotating electrode atomization granulation method is replaced by crusher crushing, and the particle size of the obtained tungsten silicon alloy powder is 40-80μm.

[0077] The oxygen content of the tungsten silicon targets prepared in Examples 1-4 and Comparative Example 1 was detected using an oxygen analyzer. The results are shown in Table 1.

[0078] The density of the tungsten silicon targets prepared in Examples 1-4 and Comparative Example 1 was tested by the drainage method. The results are shown in Table 1.

[0079] Table 1

[0080] Oxygen content / ppm Density / % Example 1 ≤300 99.98 Example 2 ≤300 99.95 Example 3 ≤300 99.99 Example 4 ≤300 99.85 Comparative Example 1 ≤1500 99.32

[0081] From the data in Table 1, we can see the following points:

[0082] (1) From the data of Examples 1-4, it can be seen that the method provided by the present invention can make the oxygen content of the tungsten silicon target material reach below 300 ppm and the density reach above 99.85%. Under optimal conditions, the oxygen content reaches below 300 ppm and the density reaches above 99.95%.

[0083] (2) A comprehensive comparison of the data of Example 1 and Example 4 shows that the only difference between Example 4 and Example 1 is that the rotation speed of the ingot during the granulation process is not within the preferred range of the present invention, and the density in Example 1 is significantly better than that in Example 4. It can be seen that the present invention can further improve the density of the product by preferably controlling the rotation speed of the ingot during the granulation process.

[0084] (3) A comprehensive comparison of the data of Example 1 and Comparative Example 1 shows that the only difference between Comparative Example 1 and Example 1 is that a crusher is used for crushing. The oxygen content and density in Example 1 are significantly better than those in Comparative Example 1. It can be seen that the method provided by the present invention can improve the density of the product and reduce the oxygen content.

[0085] In summary, the method provided by the present invention can reduce the oxygen content of the tungsten silicon target, avoid the introduction of metal and non-metal impurities, and improve the density of the target.

[0086] 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 tungsten silicon target material based on a plasma rotating electrode atomization method, characterized in that: The method comprises the following steps: (1) subjecting tungsten silicon raw materials to vacuum suspension melting to obtain alloy liquid; (2) pouring and pulling the alloy liquid obtained in step (1) in sequence to obtain an ingot; (3) grinding the ingot obtained in step (2), and then granulating it by plasma rotating electrode atomization method to obtain tungsten silicon alloy powder; (4) hot pressing and sintering the tungsten-silicon alloy powder obtained in step (3) to obtain a tungsten-silicon target.

2. The method according to claim 1, characterized in that The tungsten silicon raw material in step (1) includes mixed particles of silicon and tungsten or tungsten silicon alloy particles; Preferably, the particle size of the tungsten silicon raw material is 3-15 mm; Preferably, the purity of the tungsten silicon raw material is ≥99.999%.

3. The method according to claim 1 or 2, characterized in that: The tungsten silicon raw material in step (1) is pretreated before vacuum suspension smelting; Preferably, the pretreatment method includes ultrasonic cleaning and vacuum packaging performed sequentially; Preferably, the ultrasonic cleaning solution comprises water; Preferably, the ultrasonic cleaning time is 10-15 minutes.

4. The method according to any one of claims 1 to 3, characterized in that: The temperature of the vacuum suspension smelting in step (1) is 2300-2400° C. Preferably, the vacuum suspension smelting time is 50-70 minutes.

5. The method according to any one of claims 1 to 4, characterized in that: The casting mold in step (2) comprises a graphite mold; Preferably, the ingot pulling speed is ≤15 mm / min; Preferably, the mass percentage of silicon in the ingot is 28-30%.

6. The method according to any one of claims 1 to 5, characterized in that: The grinding in step (3) includes: removing the carburized layer on the surface of the ingot by cylindrical grinding; Preferably, the grinding wheel for the external cylindrical grinding comprises a diamond grinding wheel; Preferably, the roundness of the ingot after grinding is 0.022-0.027 mm; Preferably, the straightness of the ingot after grinding is 0.03-0.05 mm.

7. The method according to any one of claims 1 to 6, characterized in that: The rotation speed of the ingot during the granulation process of step (3) is 9000-11000 r / min; Preferably, the granulation is carried out under a protective atmosphere; Preferably, the protective atmosphere comprises argon; Preferably, the sphericity of the tungsten silicon alloy powder is ≥0.98; Preferably, the particle size of the tungsten silicon alloy powder is 45-135 μm.

8. The method according to any one of claims 1 to 7, characterized in that: The temperature of the hot pressing sintering in step (4) is 1300-1400°C.

9. The method according to any one of claims 1 to 8, characterized in that: The hot pressing sintering time in step (4) is 2.5-3.5 hours.

10. The method according to any one of claims 1 to 9, characterized in that: The method comprises the following steps: (1) ultrasonically cleaning the tungsten silicon raw material in water for 10-15 minutes, and then vacuum packaging to obtain a pretreated tungsten silicon raw material; removing the pretreated tungsten silicon raw material from the packaging, and then vacuum suspension melting at a temperature of 2300-2400° C. for 50-70 minutes to obtain an alloy liquid; (2) pouring the alloy liquid obtained in step (1) into a graphite mold, and then pulling an ingot, controlling the pulling rate to be ≤15 mm / min, to obtain an ingot, wherein the mass percentage of silicon in the ingot is 28-30%; (3) using a diamond grinding wheel to perform external cylindrical grinding on the ingot obtained in step (2) to remove the carburized layer on the surface, wherein the roundness of the ingot after external cylindrical grinding is 0.022-0.027 mm, and the straightness is 0.03-0.05 mm, and then using a plasma rotating electrode atomization method to perform granulation in an argon atmosphere, and controlling the rotation speed of the ingot during the granulation process to be 9000-11000 r / min to obtain a tungsten silicon alloy powder, wherein the sphericity of the tungsten silicon alloy powder is ≥0.98 and the particle size is 45-135 μm; (4) The tungsten-silicon alloy powder obtained in step (3) is hot-pressed and sintered at 1300-1400° C. for 2.5-3.5 hours to obtain a tungsten-silicon target.