Nickel plating method for tungsten silicon alloy target

Abstract

The present invention relates to a nickel plating method for a tungsten-silicon alloy target, the nickel plating method comprising the following steps: (1) subjecting the tungsten-silicon alloy target to a first cleaning treatment, an activation treatment, a first immersion heat treatment, and a second immersion heat treatment in sequence to obtain a pretreated target; (2) immersing the pretreated target obtained in step (1) in a nickel plating solution for nickel plating, and then sequentially subjecting the target to a third immersion heat treatment, a fourth immersion heat treatment, and a drying treatment to obtain a nickel-plated target. The nickel plating method provided by the present invention can form a nickel plating layer on the surface of the tungsten-silicon alloy, thereby improving the bonding strength between the tungsten-silicon alloy target and the back plate, and can also avoid the problem of cracking of the tungsten-silicon alloy target during processing.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor manufacturing, and in particular to a nickel plating method for a tungsten-silicon alloy target. Background Art

[0002] Tungsten-silicon alloy, an alloy composed of tungsten and silicon, boasts advantages such as high temperature tolerance, high strength, and corrosion resistance, and is widely used in aviation, energy, semiconductors, and other fields. Tungsten-silicon alloy targets are a key material used in technologies such as ion implantation, physical vapor deposition, and magnetron sputtering.

[0003] In the semiconductor industry, the target assembly is composed of a target material that meets the sputtering performance requirements and a backing plate that can be combined with the target material and has a certain strength. The backing plate can play a supporting role when the target assembly is assembled to the sputtering base and has the function of conducting heat. During the sputtering process, the working environment of the target assembly is relatively harsh. For example, the ambient temperature of the target assembly is relatively high, which can reach 300-600℃; in addition, one side of the target assembly is strongly cooled by cooling water, while the other side is at 10 -9 Pa in a high vacuum environment, a huge pressure difference is formed on the opposite sides of the target assembly; in addition, the target assembly is in a high-voltage electric field and magnetic field, and is bombarded by various particles. In such a harsh environment, if the bonding strength between the target material and the backing plate in the target assembly is poor, the target assembly will deform and crack under heat conditions, and will fall off from the bonded backing plate, making it impossible to achieve uniform sputtering. It may also cause damage to the sputtering base. Especially for tungsten silicon targets, due to the large difference in melting points between the target material and the backing plate, it is difficult to ensure good welding bonding strength, which in turn limits the further development of tungsten silicon alloy targets in the field of integrated circuit coating.

[0004] Therefore, how to improve the welding effect of the tungsten silicon alloy target and the backing plate and avoid the target cracking is a technical problem that needs to be solved in this field. Summary of the Invention

[0005] In response to the above problems, the purpose of the present invention is to provide a nickel plating method for tungsten silicon alloy. Compared with the existing technology, the nickel plating method provided by the present invention can form a nickel plating layer on the surface of the tungsten silicon alloy, so that the target material and the solder can be well wetted and bonded through the nickel plating layer, thereby improving the bonding strength between the tungsten silicon alloy target material and the backing plate, and at the same time avoiding the cracking problem of the tungsten silicon alloy during the processing process.

[0006] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0007] The present invention provides a nickel plating method for a tungsten-silicon alloy target, the nickel plating method comprising the following steps:

[0008] (1) subjecting a tungsten silicon alloy target to a first cleaning treatment, an activation treatment, a first soaking heat treatment, and a second soaking heat treatment in sequence to obtain a pretreated target;

[0009] (2) Immersing the pretreated target obtained in step (1) in a nickel plating solution for nickel plating, and then sequentially performing a third immersion heat treatment, a fourth immersion heat treatment and a drying treatment to obtain a nickel-plated target.

[0010] In the present invention, on the one hand, the granular impurities on the surface of the target are removed by a first cleaning treatment, and then the reactivity of the target surface is enhanced by an activation treatment, thereby enhancing the speed and thickness of the nickel layer formed on the surface of the target in the subsequent nickel plating treatment. By forming a nickel layer on the tungsten silicon alloy target, the tungsten silicon alloy target and the solder can be well wetted and bonded, thereby enhancing the welding bonding strength between the target and the back plate. On the other hand, before nickel plating, the acid liquid on the surface is removed by a first immersion heat treatment, and the water temperature of the first immersion heat treatment and the second immersion heat treatment is controlled to reduce the residual stress that may be generated inside the target during the processing. At the same time, the target is preheated to avoid cracking of the tungsten silicon alloy target due to rapid cooling and heating; after nickel plating, the nickel plating liquid on the surface is removed by a third immersion heat treatment, and the internal stress of the target is further reduced by controlling the water temperature of the third immersion heat treatment and the fourth immersion heat treatment, which helps to quickly evaporate the moisture on the surface of the target during the subsequent drying process, thereby avoiding the problem of target cracking due to rapid cooling. In summary, the nickel plating method provided by the present invention can not only form a nickel layer on the surface of the tungsten-silicon alloy target material to enhance the wetting effect of the target material and the solder, and improve the welding bonding strength between the target material and the back plate, but also avoid cracking of the target material.

[0011] Preferably, the first cleaning treatment in step (1) includes rinsing the target material with pure water.

[0012] Preferably, the flushing pressure in the first cleaning treatment is 25-50kPa, for example, it can be 25kPa, 26kPa, 27kPa, 28kPa, 30kPa, 32kPa, 34kPa, 36kPa, 38kPa, 40kPa, 42kPa, 44kPa, 46kPa, 48kPa or 50kPa, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0013] Preferably, the time of the first cleaning treatment is 1-3 minutes, for example, it can be 1 minute, 1.2 minutes, 1.4 minutes, 1.6 minutes, 1.8 minutes, 2 minutes, 2.2 minutes, 2.4 minutes, 2.6 minutes, 2.8 minutes or 3 minutes, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0014] Preferably, the activation treatment in step (1) includes soaking the target material in an acid solution.

[0015] Preferably, the acid solution comprises a mixed acid solution containing hydrofluoric acid and nitric acid.

[0016] Preferably, the mass ratio of hydrofluoric acid, nitric acid and water in the mixed acid solution is (0.5-1.5):(1.5-2.5):(2.5-3.5), for example, it can be 0.5:2:3, 1:2:3, 1.2:2:3, 1.5:2:3, 1:1.5:3, 1:2.5:3, 1:2:2.5 or 1:2:3.5, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0017] In the present invention, by preferably controlling the mass ratio of hydrofluoric acid, nitric acid and water in the mixed acid solution within a specific range, the surface of the tungsten-silicon alloy target can be effectively activated, the plating property of the target surface can be enhanced, the thickness of the nickel layer can be ensured to meet the technical requirements, and the welding strength between the tungsten-silicon alloy target and the back plate can be enhanced.

[0018] Preferably, the activation treatment time is 0.5-1.5 min, for example, it can be 0.5 min, 0.6 min, 0.8 min, 1 min, 1.2 min, 1.4 min or 1.5 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0019] Preferably, the temperature of the mixed acid solution is 25-35°C, for example, 25°C, 26°C, 28°C, 30°C, 32°C, 34°C or 35°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0020] Preferably, the first immersion heat treatment in step (1) comprises immersing the target material in pure water.

[0021] Preferably, the time for the first immersion heat treatment is 4-6 min, for example, it can be 4 min, 4.2 min, 4.6 min, 4.8 min, 5 min, 5.2 min, 5.4 min, 5.6 min, 5.8 min or 6 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0022] Preferably, the water temperature of the first immersion heat treatment is 45-55°C, for example, it can be 45°C, 46°C, 48°C, 50°C, 52°C, 54°C or 55°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0023] Preferably, the second immersion heat treatment in step (1) comprises immersing the target material in pure water.

[0024] Preferably, the time for the second immersion heat treatment is 4-6 min, for example, it can be 4 min, 4.2 min, 4.6 min, 4.8 min, 5 min, 5.2 min, 5.4 min, 5.6 min, 5.8 min or 6 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0025] Preferably, the water temperature of the second immersion heat treatment is 65-75°C, for example, it can be 65°C, 66°C, 68°C, 70°C, 72°C, 74°C or 75°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0026] In the present invention, the target material can be preliminarily heated by performing the first immersion heat treatment and the second immersion heat treatment before the nickel plating treatment. In particular, by controlling the water temperature of the second immersion heat treatment within a specific range, the temperature inside and on the surface of the target material can be uniformed, which helps to relieve residual stress, reduce surface impurities, and reduce cracks that may occur in the target material during the nickel plating process.

[0027] Preferably, the nickel plating solution in step (2) comprises a medium-phosphorus nickel plating solution.

[0028] In the present invention, the source of the medium-phosphorus nickel plating solution is not particularly limited and can be any medium-phosphorus nickel plating solution commonly used in the art for nickel plating, for example, it can be a commercially available medium-phosphorus nickel plating solution, and the model can be one or more of SYC300A, SYC300B or SYC300C.

[0029] Preferably, the temperature of the nickel plating solution is 85-95°C, for example, it can be 85°C, 86°C, 88°C, 90°C, 92°C, 94°C or 95°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0030] Preferably, the nickel plating treatment time is 25-35 minutes, for example, it can be 25 minutes, 26 minutes, 28 minutes, 30 minutes, 32 minutes, 34 minutes or 35 minutes, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0031] Preferably, the third immersion heat treatment in step (2) includes immersing the target material in pure water.

[0032] Preferably, the time of the third immersion heat treatment is 4-6 min, for example, it can be 4 min, 4.2 min, 4.6 min, 4.8 min, 5 min, 5.2 min, 5.4 min, 5.6 min, 5.8 min or 6 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0033] Preferably, the water temperature of the third immersion heat treatment is 65-75°C, for example, it can be 65°C, 66°C, 68°C, 70°C, 72°C, 74°C or 75°C, 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 third immersion heat treatment can, on the one hand, remove the nickel plating solution remaining on the surface of the target material, thereby preventing the residue from contaminating or corroding the target surface; on the other hand, by preferably controlling the water temperature of the third immersion heat treatment within a specific range, the internal stress of the target material can be relieved, and rapid cooling and heating can be avoided, thereby reducing the risk of deformation or cracking.

[0035] Preferably, the fourth immersion heat treatment in step (2) includes immersing the target material in pure water.

[0036] Preferably, the time of the fourth immersion heat treatment is 4-6 min, for example, it can be 4 min, 4.2 min, 4.6 min, 4.8 min, 5 min, 5.2 min, 5.4 min, 5.6 min, 5.8 min or 6 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0037] Preferably, the water temperature of the fourth immersion heat treatment is 55-65°C, for example, it can be 55°C, 56°C, 58°C, 60°C, 62°C, 64°C or 65°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0038] In the present invention, by performing the fourth immersion heat treatment and preferably controlling the water temperature of the fourth immersion heat treatment within a specific range, it is possible to avoid the target material from being cracked due to rapid cooling and heating, and to preliminarily heat the surface of the target material to promote rapid dehydration of the target material surface and avoid moisture remaining on the surface to cause water spots or oxidation.

[0039] Preferably, the drying time in step (2) is 25-35 min, for example, 25 min, 26 min, 28 min, 30 min, 32 min, 34 min or 35 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0040] Preferably, the drying temperature is 65-75°C, for example, 65°C, 66°C, 68°C, 70°C, 72°C, 74°C or 75°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0041] As a preferred technical solution of the present invention, the nickel plating method comprises the following steps:

[0042] (1) The tungsten silicon alloy target is first cleaned for 1-3 minutes using pure water at a pressure of 25-50 kPa, and then the target is activated for 0.5-1.5 minutes using a mixed acid solution having a temperature of 25-35°C and a mass ratio of hydrofluoric acid, nitric acid, and water of (0.5-1.5): (1.5-2.5): (2.5-3.5), and then the target is placed in pure water at a water temperature of 45-55°C for a first immersion heat treatment of 4-6 minutes, and then the target is placed in pure water at a water temperature of 65-75°C for a second immersion heat treatment of 4-6 minutes to obtain a pretreated target;

[0043] (2) The pretreated target obtained in step (1) is immersed in a medium-phosphorus nickel plating solution at a temperature of 85-95°C for nickel plating for 25-35 minutes, and then the target is placed in pure water at a water temperature of 65-75°C for a third immersion heat treatment for 4-6 minutes, and then the target is placed in pure water at a water temperature of 55-65°C for a fourth immersion heat treatment for 4-6 minutes, and finally dried at a temperature of 65-75°C for 25-35 minutes to obtain a nickel-plated target.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] The nickel plating method provided by the present invention can form a firm and uniform nickel plating layer on the surface of the tungsten-silicon alloy target material, thereby enhancing the welding bonding strength between the target material and the back plate. At the same time, it can prevent the target material from being affected by rapid cooling and heating during processing, reduce the internal stress of the target material, and reduce the risk of deformation or cracks. DETAILED DESCRIPTION

[0046] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0047] Example 1

[0048] This embodiment provides a nickel plating method for a tungsten-silicon alloy target, the nickel plating method comprising the following steps:

[0049] (1) The tungsten silicon alloy target was first cleaned for 2 minutes using pure water at a pressure of 35 kPa, and then the target was activated for 1 minute using a mixed acid solution having a temperature of 30°C and a mass ratio of hydrofluoric acid, nitric acid and water of 1:2:3. The target was then placed in pure water at a water temperature of 50°C for a first immersion heat treatment for 5 minutes, and then placed in pure water at a water temperature of 70°C for a second immersion heat treatment for 5 minutes to obtain a pretreated target;

[0050] (2) The pretreated target obtained in step (1) is immersed in a medium-phosphorus nickel plating solution (prepared using models SYC300A and SYC300B, and the amount of nickel plating solution added is 60 mL / L: 150 mL / L) at a temperature of 90°C for nickel plating for 30 minutes, and then the target is placed in pure water at a water temperature of 70°C for a third immersion heat treatment for 5 minutes, and then the target is placed in pure water at a water temperature of 60°C for a fourth immersion heat treatment for 5 minutes, and finally dried at a temperature of 70°C for 30 minutes to obtain a nickel-plated target.

[0051] Example 2

[0052] This embodiment provides a nickel plating method for a tungsten-silicon alloy target, the nickel plating method comprising the following steps:

[0053] (1) The tungsten silicon alloy target was first cleaned for 3 minutes using pure water at a pressure of 25 kPa, and then the target was activated for 0.5 minutes using a mixed acid solution having a temperature of 25°C and a mass ratio of hydrofluoric acid, nitric acid and water of 0.5:2.5:3. The target was then placed in pure water at a water temperature of 45°C for a first immersion heat treatment for 6 minutes, and then placed in pure water at a water temperature of 75°C for a second immersion heat treatment for 4 minutes to obtain a pretreated target;

[0054] (2) The pretreated target obtained in step (1) is immersed in a medium-phosphorus nickel plating solution (prepared using models SYC300A and SYC300B, and the amount of nickel plating solution added is 60 mL / L: 150 mL / L) at a temperature of 95°C for nickel plating for 25 minutes, and then the target is placed in pure water at a water temperature of 75°C for a third immersion heat treatment for 4 minutes, and then the target is placed in pure water at a water temperature of 65°C for a fourth immersion heat treatment for 4 minutes, and finally dried at a temperature of 75°C for 25 minutes to obtain a nickel-plated target.

[0055] Example 3

[0056] This embodiment provides a nickel plating method for a tungsten-silicon alloy target, the nickel plating method comprising the following steps:

[0057] (1) The tungsten silicon alloy target was first cleaned for 1 minute using pure water at a pressure of 50 kPa, and then the target was activated for 1.5 minutes using a mixed acid solution having a temperature of 35°C and a mass ratio of hydrofluoric acid, nitric acid and water of 1.5:1.5:3. The target was then placed in pure water at a water temperature of 55°C for a first immersion heat treatment for 4 minutes, and then placed in pure water at a water temperature of 65°C for a second immersion heat treatment for 6 minutes to obtain a pretreated target;

[0058] (2) The pretreated target obtained in step (1) is immersed in a medium-phosphorus nickel plating solution (prepared using models SYC300A and SYC300B, and the amount of nickel plating solution added is 60 mL / L: 150 mL / L) at a temperature of 85°C for nickel plating for 35 minutes, and then the target is placed in pure water at a water temperature of 65°C for a third immersion heat treatment for 6 minutes, and then the target is placed in pure water at a water temperature of 55°C for a fourth immersion heat treatment for 6 minutes, and finally dried at a temperature of 65°C for 35 minutes to obtain a nickel-plated target.

[0059] Example 4

[0060] This embodiment provides a nickel plating method for a tungsten-silicon alloy target. The only difference from Example 1 is that the mass ratio of hydrofluoric acid, nitric acid, and water in the mixed acid solution is 0.1:2:3.

[0061] Example 5

[0062] This embodiment provides a nickel plating method for a tungsten-silicon alloy target. The only difference from Example 1 is that the mass ratio of hydrofluoric acid, nitric acid, and water in the mixed acid solution is 1:0.1:3.

[0063] Example 6

[0064] This embodiment provides a nickel plating method for a tungsten-silicon alloy target. The only difference from Example 1 is that the water temperature of the second immersion heat treatment is 30°C.

[0065] Example 7

[0066] This embodiment provides a nickel plating method for a tungsten-silicon alloy target. The only difference from Example 1 is that the water temperature of the second immersion heat treatment is 80°C.

[0067] Example 8

[0068] This embodiment provides a nickel plating method for a tungsten-silicon alloy target. The only difference from Example 1 is that the water temperature of the third immersion heat treatment is 40°C.

[0069] Example 9

[0070] This embodiment provides a nickel plating method for a tungsten-silicon alloy target. The only difference from Example 1 is that the water temperature of the fourth immersion heat treatment is 35°C.

[0071] Comparative Example 1

[0072] This comparative example provides a nickel plating method for a tungsten-silicon alloy target. The only difference compared with Example 1 is that the first immersion heat treatment and the second immersion heat treatment are not performed, and the target is rinsed with pure water at 20°C instead.

[0073] Comparative Example 2

[0074] This comparative example provides a nickel plating method for a tungsten-silicon alloy target. The only difference compared with Example 1 is that the third immersion heat treatment and the fourth immersion heat treatment are not performed, and the target is rinsed with pure water at 20°C instead.

[0075] The thickness of the nickel-plated layer of the nickel-plated targets obtained in Examples 1-9 and Comparative Examples 1-2 was detected by metallographic microscope, and the results are shown in Table 1.

[0076] The cracking conditions of the nickel-plated targets obtained in Examples 1-9 and Comparative Examples 1-2 were tested, and the yield rates of the obtained products are shown in Table 1.

[0077] Table 1

[0078] Nickel plating thickness / μm Yield / % Example 1 9.25 99 Example 2 9.12 97 Example 3 9.01 95 Example 4 3.45 40 Example 5 2.14 20 Example 6 9.13 30 Example 7 9.55 80 Example 8 9.22 40 Example 9 9.07 50 Comparative Example 1 8.95 20 Comparative Example 2 9.14 20

[0079] The following points can be seen from the data in Table 1:

[0080] (1) From the data of Examples 1-3, it can be seen that the nickel plating method provided by the present invention can make the nickel layer thickness reach more than 9.01 μm, which is more conducive to the bonding of the target material and the back plate, improves the welding bonding strength of the target material and the back plate, and does not cause cracking problems, with a higher yield rate.

[0081] (2) Comprehensively comparing the data of Example 1 and Examples 4-5, it can be seen that the only difference between Example 4-5 and Example 1 is that the mass ratio of hydrofluoric acid, nitric acid and water is not within the preferred range of the present invention, and the thickness of the nickel plating layer in Example 1 is significantly better than that in Examples 4-5. It can be seen that the present invention can further promote the activation of the target surface and improve the nickel plating effect by preferably controlling the mass ratio of hydrofluoric acid, nitric acid and water.

[0082] (3) A comprehensive comparison of the data of Example 1 and Examples 6-7 shows that the only difference between Example 6-7 and Example 1 is that the water temperature of the second immersion heat treatment is not within the preferred range of the present invention. Example 1 can effectively avoid cracks in the target material, and the yield rate is significantly higher than that of Examples 6-7. This shows that the present invention can further release the internal stress of the target material and avoid cracking of the target material due to rapid cooling and heating by preferably controlling the water temperature of the second immersion heat treatment within a specific range.

[0083] (4) A comprehensive comparison of the data of Example 1 and Examples 8-9 shows that the only difference between Example 8-9 and Example 1 is that the water temperatures of the third immersion heat treatment and the fourth immersion heat treatment are not within the preferred range of the present invention, and the yield rate in Example 1 is significantly higher than that in Examples 8-9. This shows that the present invention can further release the internal stress of the target material and avoid cracking of the target material due to rapid cooling and heating by preferably controlling the water temperatures of the third immersion heat treatment and the fourth immersion heat treatment within a specific range.

[0084] (5) A comprehensive comparison of the data of Example 1 and Comparative Examples 1-2 shows that the only difference between Comparative Example 1 and Example 1 is that the first immersion heat treatment and the second immersion heat treatment are not performed, and the only difference between Comparative Example 2 and Example 1 is that the third immersion heat treatment and the fourth immersion heat treatment are not performed. The yield rate in Example 1 is significantly higher than that in Comparative Examples 1-2. It can be seen that the present invention can effectively avoid the problem of target cracking by controlling the immersion heat treatment before and after the nickel plating treatment.

[0085] In summary, the nickel plating method provided by the present invention can form a firm and uniform nickel plating layer on the surface of the tungsten-silicon alloy target, enhance the welding bonding strength between the target and the back plate, and at the same time avoid the target from being affected by rapid cooling and heating during processing, reduce the internal stress of the target, and reduce the risk of deformation or cracks.

[0086] The applicant declares that the above is only a specific embodiment of the present invention, but the scope of protection 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 fall within the scope of protection and disclosure of the present invention.

Claims

1. A nickel plating method for a tungsten-silicon alloy target, characterized in that: The nickel plating method comprises the following steps: (1) subjecting a tungsten silicon alloy target to a first cleaning treatment, an activation treatment, a first soaking heat treatment, and a second soaking heat treatment in sequence to obtain a pretreated target; The activation treatment includes soaking the target material in an acid solution; The acid solution includes a mixed acid solution containing hydrofluoric acid and nitric acid; The mass ratio of hydrofluoric acid, nitric acid and water in the mixed acid solution is (0.5-1.5):(1.5-2.5):(2.5-3.5); The first immersion heat treatment comprises immersing the target material in pure water; the water temperature of the first immersion heat treatment is 45-55°C; The second immersion heat treatment comprises immersing the target material in pure water; the water temperature of the second immersion heat treatment is 65-75°C; (2) soaking the pretreated target obtained in step (1) in a nickel plating solution for nickel plating, and then sequentially performing a third soaking heat treatment, a fourth soaking heat treatment and a drying treatment to obtain a nickel-plated target; The third immersion heat treatment comprises immersing the target material in pure water; the water temperature of the third immersion heat treatment is 65-75°C; The fourth immersion heat treatment includes immersing the target material in pure water; the water temperature of the fourth immersion heat treatment is 55-65°C.

2. The nickel plating method according to claim 1, wherein Step (1) The first cleaning treatment includes rinsing the target material with pure water.

3. The nickel plating method according to claim 1, wherein The flushing pressure in the first cleaning process is 25-50 kPa.

4. The nickel plating method according to claim 1, wherein The first cleaning process lasts for 1-3 minutes.

5. The nickel plating method according to claim 1, wherein The activation treatment time in step (1) is 0.5-1.5 min.

6. The nickel plating method according to claim 1, wherein The temperature of the mixed acid solution in step (1) is 25-35°C.

7. The nickel plating method according to claim 1, wherein The time of the first immersion heat treatment is 4-6 minutes.

8. The nickel plating method according to claim 1, wherein The second immersion heat treatment time is 4-6 minutes.

9. The nickel plating method according to claim 1, wherein The nickel plating solution in step (2) includes a medium-phosphorus nickel plating solution.

10. The nickel plating method according to claim 1, wherein The temperature of the nickel plating solution is 85-95°C.

11. The nickel plating method according to claim 1, wherein The nickel plating treatment time is 25-35 minutes.

12. The nickel plating method according to claim 1, wherein The time of the third immersion heat treatment is 4-6 minutes.

13. The nickel plating method according to claim 1, wherein The fourth immersion heat treatment lasts for 4-6 minutes.

14. The nickel plating method according to claim 1, wherein The drying time in step (2) is 25-35 minutes.

15. The nickel plating method according to claim 1, wherein The temperature of the drying process is 65-75°C.

16. The nickel plating method according to claim 1, wherein The nickel plating method comprises the following steps: (1) The tungsten silicon alloy target is first cleaned for 1-3 minutes using pure water at a pressure of 25-50 kPa, and then the target is activated for 0.5-1.5 minutes using a mixed acid solution having a temperature of 25-35°C and a mass ratio of hydrofluoric acid, nitric acid, and water of (0.5-1.5): (1.5-2.5): (2.5-3.5), and then the target is placed in pure water at a water temperature of 45-55°C for a first immersion heat treatment of 4-6 minutes, and then the target is placed in pure water at a water temperature of 65-75°C for a second immersion heat treatment of 4-6 minutes to obtain a pretreated target; (2) The pretreated target obtained in step (1) is immersed in a medium-phosphorus nickel plating solution at a temperature of 85-95°C for nickel plating for 25-35 minutes, and then the target is placed in pure water at a water temperature of 65-75°C for a third immersion heat treatment for 4-6 minutes, and then the target is placed in pure water at a water temperature of 55-65°C for a fourth immersion heat treatment for 4-6 minutes, and finally dried at a temperature of 65-75°C for 25-35 minutes to obtain a nickel-plated target.