Treatment method for rust removal and rust prevention of copper target material

Abstract

The invention relates to a rust removal and prevention treatment method for a copper target material, which comprises the following steps: (1) soaking the copper target material in a rust removal solution to remove rust to obtain a first target material; (2) cleaning the first target material obtained in the step (1) to obtain a second target material; and (3) soaking and passivating the second target material obtained in the step (2) by adopting a passivation solution, and then drying to obtain the treated target material. According to the method, operation is easy, raw materials are easy to obtain, the surface of the treated copper target is free of rust, secondary rusting is not likely to happen, and the surface requirement of a copper target product is met.

Description

Technical Field

[0001] The invention relates to the technical field of target materials, and in particular to a method for removing and preventing rust from a copper target material. Background Art

[0002] In the field of semiconductor manufacturing, copper targets are a representative type of material, and their surface quality has a significant impact on device performance. In traditional processing technology, lathe finishing is a common means of surface treatment of copper targets. However, during the processing, the use of cutting fluid can effectively reduce the cutting temperature and improve processing efficiency, but it also makes the surface of the copper target prone to slight rust. The formation of this rust affects the sputtering performance of the target, reduces the stability and reliability of semiconductor devices, and becomes a hidden danger in semiconductor processing or use. In addition, the rust may further oxidize in a high-temperature environment, forming oxides that are more difficult to remove, further reducing the service life of the target.

[0003] Currently, existing processing techniques cannot address rust without implementing any rust prevention and removal processes, hindering improvements in semiconductor product quality and production. While a variety of rust prevention and removal products are available on the market, most suffer from complex procedures, high costs, or the tendency to cause secondary damage to the target surface, making them difficult to meet the high-precision, high-cleanliness processing requirements of semiconductor copper targets.

[0004] Existing rust prevention and removal technologies are primarily categorized as physical and chemical. While physical methods, such as drying and vacuum packaging, can prevent rust to a certain extent, they cannot completely eliminate existing rust. Furthermore, they are complex and costly to operate in practice. Chemical methods, such as the use of rust inhibitors and removers, can corrode the target surface and offer limited rust prevention effectiveness.

[0005] Therefore, providing a method for rust prevention and rust removal for copper targets is a technical problem that needs to be solved in the current field. Summary of the Invention

[0006] In response to the above problems, the purpose of the present invention is to provide a method for removing and preventing rust from copper targets. Compared with the prior art, the method provided by the present invention is simple to operate, the raw materials are easy to obtain, and after treatment, the surface of the copper target is free of rust and is not prone to secondary rust, thereby meeting the surface requirements of copper target products.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] The present invention provides a method for removing and preventing rust from a copper target material, the method comprising the following steps:

[0009] (1) soaking and removing rust from a copper target material using a rust removal liquid to obtain a first target material;

[0010] (2) cleaning the first target material obtained in step (1) to obtain a second target material;

[0011] (3) The second target material obtained in step (2) is immersed in a passivation solution for passivation, and then dried to obtain a treated target material.

[0012] In the treatment method provided by the present invention, by sequentially performing immersion rust removal, cleaning and immersion passivation, not only can the rust on the target surface caused by the cutting fluid be removed, but also secondary rust can be avoided.

[0013] Preferably, the rust removal liquid in step (1) comprises, by weight percentage, 30-50% phosphoric acid, 20-40% ethylene glycol monobutyl ether, and the balance water.

[0014] In the present invention, the phosphoric acid content in the rust removing liquid is 30-50%, for example, it can be 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49% or 50%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0015] In the present invention, the content of ethylene glycol monobutyl ether in the rust removing liquid is 20-40%, for example, it can be 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39% or 40%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0016] In the present invention, by optimally controlling the composition of the rust removal solution, phosphoric acid, as an acidic component, can chemically react with rust (primarily metal oxides) on the metal surface to form water-soluble salts, thereby removing the rust from the metal surface. Furthermore, by optimally controlling the mass percentage of the phosphoric acid, the rust removal effect can be achieved while avoiding affecting the surface gloss of the target material.

[0017] In the present invention, the soaking and rust removal time in step (1) is 30-40s, for example, it can be 30s, 31s, 32s, 33s, 34s, 35s, 36s, 37s, 38s, 39s or 40s, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0018] Preferably, the cleaning in step (2) comprises washing with water and soaking in isopropyl alcohol in sequence.

[0019] Preferably, the washing time is 290-310s, for example, it can be 290s, 291s, 292s, 293s, 294s, 295s, 296s, 297s, 298s, 299s, 300s, 301s, 302s, 303s, 304s, 305s, 306s, 307s, 308s, 309s or 310s, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0020] In the present invention, by preferably controlling the water washing time within a specific range, on the one hand, it is beneficial to fully remove the rust removal liquid on the surface, and on the other hand, it avoids rusting of the target material due to excessive time.

[0021] Preferably, the isopropyl alcohol immersion time is 280-300s, for example, it can be 280s, 281s, 282s, 283s, 284s, 285s, 286s, 287s, 288s, 290s, 291s, 292s, 293s, 294s, 295s, 296s, 297s, 298s, 299s or 300s, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0022] In the present invention, the purpose of soaking in isopropyl alcohol is to utilize the volatility of isopropyl alcohol. After soaking in isopropyl alcohol, the water on the surface of the target material evaporates together with the isopropyl alcohol, thereby avoiding oxidation of the target material caused by residual water and ensuring high processing efficiency.

[0023] Preferably, the components of the passivation solution in step (3) include, by weight percentage, 5-7% sulfuric acid, 4-6% sulfonic acid, 3-5% ethylene glycol monobutyl ether, 3-5% alkyl glycoside, and the balance water.

[0024] Among the present invention, sulfuric acid is 5-7% in the passivating solution, for example, can be 5%, 5.1%, 5.2%, 5.3%, 5.4%, 5.5%, 5.6%, 5.7%, 5.8%, 5.9%, 6%, 6.1%, 6.2%, 6.3%, 6.4%, 6.5%, 6.6%, 6.7%, 6.8%, 6.9% or 7%, but is not limited to enumerated numerical value, and other unenumerated numerical values ​​are applicable equally in the numerical range.

[0025] In the present invention, sulfonic acid is 4-6% in the passivating solution, for example, can be 4%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, 4.6%, 4.7%, 4.8%, 4.9%, 5%, 5.1%, 5.2%, 5.3%, 5.4%, 5.5%, 5.6%, 5.7%, 5.8%, 5.9% or 6%, but is not limited to enumerated numerical value, and other unenumerated numerical values ​​in the numerical range are equally applicable.

[0026] In the present invention, the content of ethylene glycol monobutyl ether in the passivating solution is 3-5%, for example, it can be 3%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, 4%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, 4.6%, 4.7%, 4.8%, 4.9% or 5%, but is not limited to the enumerated values, and other unenumerated values ​​within the numerical range are equally applicable.

[0027] In the present invention, the alkyl glycoside content in the passivating solution is 3-5%, for example, it can be 3%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, 4%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, 4.6%, 4.7%, 4.8%, 4.9% or 5%, but is not limited to the enumerated values, and other unenumerated values ​​within the numerical range are equally applicable.

[0028] In the present invention, by preferentially controlling the composition of the passivation solution, during the passivation process, the passivation solution can form a passivation film on the surface of the target material. The passivation film acts as a barrier to isolate the metal substrate from the external environment, preventing oxygen, moisture and other corrosive media from contacting the metal, thereby preventing oxidation and corrosion, and increasing the electrode potential of the metal, making it more stable in the electrochemical corrosion system. Moreover, when the film layer is slightly damaged, oxygen in the environment can re-react with the metal elements in the passivation film to repair the damaged area, thereby achieving a good protective effect.

[0029] Preferably, the immersion passivation time is 280-300s, for example, it can be 280s, 282s, 284s, 286s, 288s, 290s, 292s, 294s, 296s, 298s or 300s, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0030] Preferably, the drying temperature in step (3) is 75-85°C, for example, it can be 75°C, 76°C, 77°C, 78°C, 79°C, 80°C, 81°C, 82°C, 83°C, 84°C or 85°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0031] Preferably, the drying time is 290-310s, for example, it can be 290s, 291s, 292s, 293s, 294s, 295s, 296s, 297s, 298s, 299s, 300s, 301s, 302s, 303s, 304s, 305s, 306s, 307s, 308s, 309s or 310s, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0032] As a preferred technical solution of the present invention, the processing method comprises the following steps:

[0033] (1) soaking a copper target in a rust removal solution for 30-40 seconds to remove rust, thereby obtaining a first target, wherein the rust removal solution comprises, by weight percentage, 30-50% phosphoric acid, 20-40% ethylene glycol monobutyl ether, and the remainder water;

[0034] (2) cleaning the first target obtained in step (1), wherein the cleaning comprises first washing with water for 290-310 seconds and then soaking in isopropyl alcohol for 280-300 seconds to obtain a second target;

[0035] (3) The second target material obtained in step (2) is immersed in a passivation solution for passivation for 280-300 seconds, and then dried at a temperature of 75-85° C. for 290-310 seconds to obtain a treated target material, wherein the components of the passivation solution are calculated by weight percentage, including 5-7% sulfuric acid, 4-6% sulfonic acid, 3-5% ethylene glycol monobutyl ether, 3-5% alkyl glycoside, and the balance is water.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] (1) The treatment method provided by the present invention can effectively remove rust on the surface of the copper target, improve the surface quality of the target, ensure the surface gloss of the target, and meet the requirements for the surface quality of the copper target product.

[0038] (2) The treatment method provided by the present invention has low process cost, the raw materials are easy to obtain and the amount used is small, the process operation is simple, and it is easy to integrate into the existing production process, which is conducive to industrial application. DETAILED DESCRIPTION

[0039] 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.

[0040] Example 1

[0041] This embodiment provides a method for removing and preventing rust from a copper target, the method comprising the following steps:

[0042] (1) soaking a copper target in a rust removal solution for 35 seconds to remove rust, thereby obtaining a first target, wherein the rust removal solution comprises, by weight percentage, 40% phosphoric acid, 30% ethylene glycol monobutyl ether, and the remainder water;

[0043] (2) cleaning the first target obtained in step (1), wherein the cleaning comprises first washing with water for 300 seconds and then soaking in isopropyl alcohol for 290 seconds to obtain a second target;

[0044] (3) The second target material obtained in step (2) is immersed in a passivation solution for passivation for 290 seconds, and then dried at 80° C. for 300 seconds to obtain a treated target material, wherein the components of the passivation solution are calculated by weight percentage, including 6% sulfuric acid, 5% sulfonic acid, 4% ethylene glycol monobutyl ether, 4% alkyl glycoside, and the balance is water.

[0045] Example 2

[0046] This embodiment provides a method for removing and preventing rust from a copper target, the method comprising the following steps:

[0047] (1) soaking a copper target in a rust removal solution for 30 seconds to remove rust, thereby obtaining a first target, wherein the rust removal solution comprises, by weight percentage, 50% phosphoric acid, 20% ethylene glycol monobutyl ether, and the remainder water;

[0048] (2) cleaning the first target obtained in step (1), wherein the cleaning comprises first washing with water for 310 seconds and then soaking in isopropyl alcohol for 280 seconds to obtain a second target;

[0049] (3) The second target material obtained in step (2) is immersed in a passivation solution for passivation for 300 seconds, and then dried at a temperature of 75° C. for 310 seconds to obtain a treated target material, wherein the components of the passivation solution are calculated by weight percentage, including 5% sulfuric acid, 6% sulfonic acid, 3% ethylene glycol monobutyl ether, 5% alkyl glycoside, and the balance is water.

[0050] Example 3

[0051] This embodiment provides a method for removing and preventing rust from a copper target, the method comprising the following steps:

[0052] (1) soaking a copper target in a rust removal solution for 40 seconds to remove rust, thereby obtaining a first target, wherein the rust removal solution comprises, by weight percentage, 30% phosphoric acid, 40% ethylene glycol monobutyl ether, and the remainder water;

[0053] (2) cleaning the first target obtained in step (1), wherein the cleaning comprises first washing with water for 290 seconds and then soaking in isopropyl alcohol for 300 seconds to obtain a second target;

[0054] (3) The second target material obtained in step (2) is immersed in a passivation solution for passivation for 280 seconds, and then dried at 85° C. for 290 seconds to obtain a treated target material, wherein the components of the passivation solution are calculated by weight percentage, including 7% sulfuric acid, 4% sulfonic acid, 5% ethylene glycol monobutyl ether, 3% alkyl glycoside, and the balance is water.

[0055] Example 4

[0056] This embodiment provides a method for removing and preventing rust from a copper target. The difference between the treatment method and Example 1 is that ethylene glycol monobutyl ether is not added to the rust removal solution, but is replaced by phosphoric acid with an equal mass percentage.

[0057] Example 5

[0058] This embodiment provides a method for removing and preventing rust from a copper target. The difference between the treatment method and Example 1 is that phosphoric acid is not added to the rust removal solution, but is replaced by ethylene glycol monobutyl ether with an equal mass percentage.

[0059] Example 6

[0060] This embodiment provides a method for removing and preventing rust from a copper target. The difference between the treatment method and Example 1 is that sulfuric acid is not added to the passivation solution, but is replaced by sulfonic acid, ethylene glycol monobutyl ether, and alkyl glycoside, which are distributed according to their original mass ratio.

[0061] Example 7

[0062] This embodiment provides a method for removing and preventing rust from a copper target. The difference between the treatment method and Example 1 is that sulfonic acid is not added to the passivation solution, but is replaced by sulfuric acid, ethylene glycol monobutyl ether, and alkyl glycoside, which are distributed according to their original mass ratio.

[0063] Example 8

[0064] This embodiment provides a method for removing and preventing rust from a copper target. The difference between the treatment method and Example 1 is that ethylene glycol monobutyl ether is not added to the passivation solution, but is replaced by sulfuric acid, sulfonic acid and alkyl glycoside, which are distributed according to the original mass ratio of the three.

[0065] Example 9

[0066] This embodiment provides a method for removing and preventing rust from a copper target. The difference between the treatment method and Example 1 is that alkyl glycoside is not added to the passivation solution, but is replaced by sulfuric acid, sulfonic acid and ethylene glycol monobutyl ether, which are distributed according to their original mass ratio.

[0067] Rust removal effect: The treated target material obtained in the above embodiment was tested to see whether there was rust and metallic luster. The results are shown in Table 1.

[0068] Anti-rust effect: The treated target was placed in an environment with a temperature of 50° C. and a humidity of 80%, and the time when rust began to form was recorded. The results are shown in Table 1.

[0069] Table 1

[0070]

[0071]

[0072] In Table 1, “ / ” indicates that the rust removal was incomplete and no anti-rust effect test was performed.

[0073] From Table 1 we can see that:

[0074] (1) It can be seen from Examples 1-3 that the method provided by the present invention can effectively remove rust on the surface of the target material under optimal conditions and make the surface of the target material have a metallic luster. It has a good anti-rust effect in a high temperature and high humidity environment. In an environment with a temperature of 50°C and a humidity of 80%, the anti-rust effect can reach more than 58 days.

[0075] (2) From the data of Example 1 and Examples 4-9, it can be seen that the present invention can further improve the rust removal and rust prevention effects by optimally controlling the components of the rust removal liquid and the passivation liquid.

[0076] In summary, the method provided by the present invention is simple to operate, the raw materials are easy to obtain, and the surface of the copper target material after treatment is free of rust and is not prone to secondary rust, thus meeting the surface requirements of the copper target material product.

[0077] 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 method for removing rust and preventing rust from a copper target, characterized in that: The processing method comprises the following steps: (1) soaking and removing rust from a copper target material using a rust removal liquid to obtain a first target material; (2) cleaning the first target material obtained in step (1) to obtain a second target material; (3) The second target material obtained in step (2) is immersed in a passivation solution for passivation, and then dried to obtain a treated target material.

2. The processing method according to claim 1, characterized in that The components of the rust removal liquid in step (1) include 30-50% phosphoric acid, 20-40% ethylene glycol monobutyl ether, and the balance water, calculated by weight percentage.

3. The processing method according to claim 1 or 2, characterized in that The soaking and rust removal time in step (1) is 30-40s.

4. The processing method according to any one of claims 1 to 3, characterized in that The cleaning in step (2) includes washing with water and soaking in isopropyl alcohol in sequence.

5. The processing method according to claim 4, characterized in that: The water washing time is 290-310s.

6. The processing method according to claim 4, characterized in that: The isopropyl alcohol soaking time is 280-300s.

7. The processing method according to any one of claims 1 to 6, characterized in that: The components of the passivation solution in step (3) are calculated by weight percentage, including 5-7% sulfuric acid, 4-6% sulfonic acid, 3-5% ethylene glycol monobutyl ether, 3-5% alkyl glycoside, and the balance is water.

8. The processing method according to any one of claims 1 to 7, characterized in that: The immersion passivation time in step (3) is 280-300s.

9. The processing method according to any one of claims 1 to 8, characterized in that: The drying temperature in step (3) is 75-85°C; Preferably, the drying time is 290-310s.

10. The processing method according to any one of claims 1 to 9, characterized in that: The processing method comprises the following steps: (1) soaking a copper target in a rust removal solution for 30-40 seconds to remove rust, thereby obtaining a first target, wherein the rust removal solution comprises, by weight percentage, 30-50% phosphoric acid, 20-40% ethylene glycol monobutyl ether, and the remainder water; (2) cleaning the first target obtained in step (1), wherein the cleaning comprises first washing with water for 290-310 seconds and then soaking in isopropyl alcohol for 280-300 seconds to obtain a second target; (3) The second target material obtained in step (2) is immersed in a passivation solution for passivation for 280-300 seconds, and then dried at a temperature of 75-85° C. for 290-310 seconds to obtain a treated target material, wherein the components of the passivation solution are calculated by weight percentage, including 5-7% sulfuric acid, 4-6% sulfonic acid, 3-5% ethylene glycol monobutyl ether, 3-5% alkyl glycoside, and the balance is water.

Images