Electrochemical polishing solution for copper and copper alloy and polishing method

Abstract

The invention provides an electrochemical polishing solution for copper and copper alloy, 1, the electrochemical polishing solution comprises an alkaline polishing agent and an acidic polishing agent, the alkaline polishing agent comprises, by mass, 20-50% of sodium hydroxide or potassium hydroxide, 1-10% of conductive salt, 1-5% of sodium nitrate, 1-10% of a copper ion complexing agent, and the balance deionized water; the acidic polishing agent comprises the following components in percentage by mass: 50-65% of phosphoric acid, 20-35% of sulfuric acid, 1-5% of a corrosion inhibitor, 1-3% of a brightener, 1-5% of a copper ion complexing agent and the balance of deionized water. The invention also provides a polishing method adopting the electrochemical polishing solution, which comprises the following steps: firstly putting a copper or pure copper sheet into the alkaline polishing agent for rough polishing, and then putting the material subjected to rough polishing into the acidic polishing agent to finish fine polishing.

Description

Technical Field

[0001] This application relates to the field of semiconductor manufacturing technology, and in particular to an electrochemical polishing method and polishing solution. Background Technology

[0002] Laser processing boasts advantages such as high energy density, fast processing speed, and minimal material deformation, leading to its wide application in microfabrication, MEMS device manufacturing, and microbial medicine. Laser processing utilizes the energy transfer between electrons and phonons to heat the crystal lattice. Through thermal diffusion within the lattice, the area surrounding the laser focal point is melted and vaporized, resulting in the ablation and removal of material.

[0003] Copper or pure copper sheets manufactured by laser subtractive processing have important applications due to their unique properties. However, the principle of laser processing results in the presence of residual metal slag during the material processing, which affects the morphology and properties of the processed material. To improve the surface quality of the material, laser-subtractive manufactured materials can be treated with mechanical polishing, chemical polishing, and electrochemical polishing. However, mechanical polishing is difficult to handle complex materials, chemical polishing generally results in uneven surface roughness, while electrochemical polishing offers good finish and high efficiency, making it a superior treatment option.

[0004] Existing electrochemical polishing technologies generally use phosphoric acid, sulfuric acid, hydrochloric acid and their mixtures. The electrochemical polishing reaction process is fast, which can easily lead to uneven polishing. However, it can effectively deal with large slag protrusions on the material surface.

[0005] Chinese Patent 202010669779.1 discloses a method for reducing the roughness of copper foil and related copper foil products. It uses an anhydrous phosphoric acid-ethanol system to prepare a polishing solution, which is then used to electrochemically polish large-grain copper foil. After polishing, the foil is cleaned, and the surface roughness can be reduced by more than 10 times. However, the polishing solution is mainly composed of anhydrous phosphoric acid, with a concentration as high as 80-90%, making it highly acidic and posing a significant operational hazard.

[0006] Chinese Patent 201911244367.7 discloses an electrochemical polishing solution for copper foil surface pretreatment and its application. It uses phosphoric acid-sulfuric acid / hydrochloric acid-viscosity regulator and deionized water to prepare the polishing solution. After pretreatment and acid washing, electrochemical polishing is performed to remove scratches and other defects from the copper foil surface. However, its operation is complex and its polishing applications are limited, making it unsuitable for various copper products. Summary of the Invention

[0007] The purpose of this application is to provide an electrochemical polishing method and polishing solution that is safe, widely applicable, and easy to operate.

[0008] To achieve the above objectives, this application adopts the following technical solution:

[0009] This application provides an electrochemical polishing solution for copper and copper alloys, comprising an alkaline polishing agent and an acidic polishing agent. The alkaline polishing agent, by mass percentage, comprises: 20%-50% sodium hydroxide or potassium hydroxide, 1%-10% conductive salt, 1%-5% sodium nitrate, 1%-10% copper ion complexing agent, and the remainder being deionized water. The acidic polishing agent, by mass percentage, comprises: 50%-65% phosphoric acid, 20%-35% sulfuric acid, 1%-5% corrosion inhibitor, 1%-3% brightener, and 1%-5% copper ion complexing agent, with the remainder being deionized water.

[0010] The alkaline polishing agent used in this technical solution has a fast reaction rate during polishing, which can effectively remove large-volume slag, dirt, or protrusions on the surface, and can effectively pre-treat the slag on the material surface. The acidic polishing agent used can treat small protrusions on the material surface through a special composition ratio, reducing surface roughness and obtaining ideal material surface conditions.

[0011] In one embodiment, the copper ion complexing agent in the alkaline polishing agent is ethylenediamine, ethylenediaminetetraacetic acid, or ammonia, and the conductive salt is sodium chloride or potassium chloride.

[0012] In one embodiment, the copper ion complexing agent in the acidic polishing agent is citric acid, phosphonate, or ethylenediaminetetraacetic acid; the brightener is sodium dodecyl sulfate, thiourea, or polyethylene glycol; and the corrosion inhibitor is benzotriazole, triphenyltetraazole chloride, or sodium nitrate.

[0013] Secondly, the present invention also provides a polishing method using the above-mentioned electrochemical polishing liquid, wherein copper or pure copper sheet is first placed in the alkaline polishing agent for coarse polishing, and then the coarsely polished material is placed in the acidic polishing agent for fine polishing.

[0014] In one embodiment, the electrochemical polishing method includes the following steps:

[0015] S1. Perform preliminary surface cleaning on the laser-processed copper or pure copper sheet;

[0016] S2. Perform UV activation treatment on the surface of the pre-cleaned copper or pure copper sheet;

[0017] S3. Place the activated copper or pure copper sheet in the alkaline polishing agent for the first step of rough polishing;

[0018] S4. Place the roughly polished copper or pure copper sheet in an acidic polishing agent for fine polishing.

[0019] This application can remove the slag generated during laser cutting. The first step of rough polishing can remove a large amount of slag, but due to the fast reaction rate, the surface roughness of the material increases. The second step of fine polishing is introduced to reduce the roughness and improve the surface quality of the material.

[0020] In one embodiment, in step S1, the copper or pure copper sheet to be polished is ultrasonically cleaned in anhydrous ethanol for 5-30 minutes, ultrasonically cleaned in a rust remover for 5-30 minutes, and ultrasonically cleaned in isopropanol for 5-30 minutes, and then dried for later use.

[0021] In one embodiment, step S2 further includes cleaning the UV-activated copper or pure copper sheet in 5% dilute sulfuric acid.

[0022] In one embodiment, in step S3, the voltage range selected for polishing is between 0.5 and 1.8 V, and the temperature of the alkaline polishing solution is maintained between 20 and 35°C.

[0023] In one embodiment, in step S4, the voltage range selected for polishing is between 0.2 and 1.2 V, and the temperature of the acidic polishing solution is maintained between 30 and 50°C.

[0024] This invention proposes an electrochemical polishing slurry and method for copper and copper alloys. The method employs a two-step polishing process: first, a basic polishing agent is used to remove large metal slag particles and scratches; then, an acidic polishing agent is used for further fine polishing, resulting in copper or pure copper sheets with high surface quality. Therefore, this invention has the advantages of high slag removal efficiency and high material surface quality, improving overall polishing efficiency and yielding copper or copper alloy materials with high surface quality. Attached Figure Description

[0025] Figure 1a A photograph of the polished metal material under a microscope in Embodiment 1 provided for this application;

[0026] Figure 1b A high-brightness photograph of the laser-processed sidewall of the polished metal material under a microscope, provided in Embodiment 1 of this application;

[0027] Figure 2a A photograph of the polished metal material under a microscope in Embodiment 2 provided for this application;

[0028] Figure 2b A high-brightness photograph of the laser-processed sidewall of the polished metal material under a microscope in Embodiment 2 provided for this application;

[0029] Figure 3a A photograph of the polished metal material under a microscope in Embodiment 3 provided for this application;

[0030] Figure 3b A high-brightness photograph of the laser-processed sidewall of the polished metal material under a microscope in Embodiment 3 provided for this application;

[0031] Figure 4 The comparative example provided for this application is a high-brightness photograph of the laser-processed sidewall of the polished metal material under a microscope. Detailed Implementation

[0032] To illustrate the technical content, structural features, achieved objectives, and effects of the invention in detail, the technical solutions of the embodiments of this application will be described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. In the following description, for illustrative purposes, numerous specific details are set forth to provide a detailed description of various exemplary embodiments or implementations of the invention. However, various exemplary embodiments may also be implemented without these specific details or in one or more equivalent arrangements. Furthermore, the various exemplary embodiments may differ, but are not necessarily exclusive. For example, the specific shape, construction, and characteristics of the exemplary embodiments may be used or implemented in another exemplary embodiment without departing from the inventive concept.

[0033] This application discloses an electrochemical polishing solution for copper and pure copper sheets, as well as an electrochemical polishing method. The method includes the following steps:

[0034] S1. Perform preliminary surface cleaning on the laser-processed copper or pure copper sheet. The preliminary cleaning process includes: ultrasonically cleaning the copper or pure copper sheet in anhydrous ethanol for 5-30 minutes, then ultrasonically cleaning it in a rust remover for 5-30 minutes, followed by ultrasonic cleaning with isopropanol for 5-30 minutes, then drying it and storing it in a nitrogen cabinet for later use.

[0035] A clean metal surface facilitates the uniformity of the anodic dissolution reaction during electrochemical polishing, improving polishing quality and efficiency. Anhydrous ethanol, with its excellent solubility, effectively removes organic contaminants such as oil and dust from metal surfaces. Rust removers primarily remove oxide scale, verdigris, and other corrosion products from metal surfaces. Isopropanol displaces adsorbed moisture on the metal surface and, through its own cleaning action, removes residual microparticles and organic matter. Ultrasonic cleaning enhances the cleaning effect, distributing the solution more evenly across the metal surface, accelerating the chemical reaction rate, and making it easier to wash away loosened rust particles.

[0036] S2, the surface of the copper or pure copper sheet obtained after preliminary cleaning is subjected to UV activation treatment. After UV activation, the copper or pure copper sheet is then cleaned in 5% dilute sulfuric acid.

[0037] UV activation is a treatment method that uses ultraviolet light irradiation to induce physical or chemical changes in materials, thereby improving surface activity and enhancing the uniformity of the electrolysis process. Ultraviolet light has high energy; when it irradiates a metal surface, it excites the atoms or molecules on the surface, placing them in a high-energy active state. These active substances have strong redox capabilities and can react with atoms at impurities or defects on the metal surface, thus altering the chemical composition and structure of the metal surface, increasing the number of active sites, and enhancing its reactivity in subsequent electropolishing processes. UV activation can increase the free energy of the metal surface. Surfaces with higher free energy are more prone to chemical reactions and physical adsorption processes. During electropolishing, metal atoms are more easily detached from the surface and enter the electrolyte. It also facilitates the adsorption and reaction of components in the polishing solution on the metal surface, thereby accelerating the electropolishing process and improving polishing efficiency.

[0038] S3. The copper or pure copper sheet cleaned in step S2, along with the fixture, is placed in an alkaline polishing agent for the first stage of rough polishing to remove large slag particles and scratches. After completion, the fixture and copper or pure copper sheet are rinsed in pure water. During the polishing process, the voltage range is selected between 0.5-1.8V, the temperature of the alkaline polishing solution is maintained between 20-35℃, and the polishing time is 1-10 minutes.

[0039] The main components of the alkaline polishing agent are 20wt%-50wt% sodium hydroxide or potassium hydroxide, 1wt%-10wt% sodium chloride or potassium chloride, 1wt%-5wt% sodium nitrate as a corrosion inhibitor, 1wt%-10wt% ethylenediamine or ethylenediaminetetraacetic acid or ammonia as a copper ion complexing agent, and deionized water.

[0040] Preferably, the content of sodium hydroxide or potassium hydroxide in the alkaline polishing agent can be 20wt%, 21wt%, 22wt%, 23wt%, 24wt%, 25wt%, 26wt%, 27wt%, 28wt%, 29wt%, 30wt%, 31wt%, 32wt%, 33wt%, 34wt%, 35wt%, 36wt%, 37wt%, 28wt%, 39wt%, 40wt%, 41wt%, 42wt%, 43wt%, 44wt%, 45wt%, 46wt%, 47wt%, 48wt%, 49wt%, or 50wt%.

[0041] Preferably, the content of sodium chloride or potassium chloride in the alkaline polishing agent can be 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, or 10 wt%.

[0042] Preferably, the sodium nitrate content in the alkaline polishing agent can be 1 wt%, 2 wt%, 3 wt%, 4 wt%, or 5 wt%.

[0043] Preferably, the content of ethylenediamine, ethylenediaminetetraacetic acid, or ammonia in the alkaline polishing agent can be 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, or 10 wt%.

[0044] Sodium hydroxide and potassium hydroxide are used as the main salts. Under high-concentration alkaline conditions, copper ions can exist in complex form without forming precipitates that adhere to the material surface. Sodium chloride or potassium chloride, as conductive salts, can increase the ion flow rate, resulting in more uniform removal, and can also reduce the voltage to prevent localized overheating of the material. Sodium nitrate, as a corrosion inhibitor, can reduce the electrolysis rate and prevent excessive removal. Ethylenediamine is a strong alkaline substance that can react with copper ions (Cu... 2+ This forms stable complexes, such as copper amine complexes. These complexes allow copper ions to dissolve rapidly from the surface of the metal material into the polishing solution, thereby accelerating the dissolution rate of copper and increasing the material removal rate. The ratio of the corrosion inhibitor sodium nitrate to the copper ion complexing agent can be 1:1, 1:2, or 1:3, which can help balance the electrolysis rate.

[0045] S4. After washing the material and fixture from step S3 (coarse polishing) with water, place them in an acidic polishing solution for fine polishing to further improve the surface smoothness and enhance the surface morphology quality. During polishing, select a voltage range of 0.2-1.2V, maintain the temperature of the acidic polishing solution between 30-50℃, and polish for 1-10 minutes. After polishing, remove the fixture and material together, rinse them with pure water, and blow them dry to obtain copper or pure copper sheets with removed metal slag and low surface roughness.

[0046] The acidic polishing agent is a sulfuric acid-phosphoric acid system, with the main components being 50wt%-65wt% phosphoric acid, 20wt%-35wt% sulfuric acid, 1wt%-5wt% benzotriazole or triphenyltetraazole chloride or sodium nitrate as corrosion inhibitors, 1wt%-3wt% sodium dodecyl sulfate or thiourea or polyethylene glycol as brighteners, and 1wt%-5wt% citric acid or phosphonates or ethylenediaminetetraacetic acid as copper ion complexing agents.

[0047] Preferably, the phosphoric acid content in the acidic polishing agent can be 50wt%, 51wt%, 52wt%, 53wt%, 54wt%, 55wt%, 56wt%, 57wt%, 58wt%, 59wt%, 60wt%, 61wt%, 62wt%, 63wt%, 64wt%, or 65wt%.

[0048] Preferably, the sulfuric acid content in the acidic polishing agent can be 20wt%, 21wt%, 22wt%, 23wt%, 24wt%, 25wt%, 26wt%, 27wt%, 28wt%, 29wt%, 30wt%, 31wt%, 32wt%, 33wt%, 34wt%, or 35wt%.

[0049] Preferably, the content of the corrosion inhibitor benzotriazole or triphenyltetrazolium chloride or sodium nitrate in the acidic polishing agent can be 1 wt%, 2 wt%, 3 wt%, 4 wt%, or 5 wt%.

[0050] Preferably, the brightener in the acidic polishing agent can be sodium dodecyl sulfate, thiourea, or polyethylene glycol, and the content can be 1 wt%, 2 wt%, or 3 wt%.

[0051] Preferably, the content of the copper ion complexing agent citric acid, phosphonate, or ethylenediaminetetraacetic acid in the acidic polishing agent can be 1 wt%, 2 wt%, 3 wt%, 4 wt%, or 5 wt%.

[0052] Sulfuric acid primarily enhances the solution's conductivity, improves dispersion, and increases current efficiency. Phosphoric acid promotes copper dissolution and forms a viscous film with copper ions in the anodic region on the material surface, improving polishing results. The corrosion inhibitor forms a passivation film to prevent excessive removal. The copper ion complexing agent rapidly dissolves copper ions from the metal surface into the polishing solution, accelerating copper dissolution and increasing material removal rate. The ratio of sodium nitrate corrosion inhibitor to copper ion complexing agent can be 1:1, 2:1, 3:1, 4:1, or 5:1 to balance the electrolysis rate. The brightener stabilizes the viscous layer, promotes selective dissolution, prevents harmful localized corrosion, and results in a smoother, more uniform surface.

[0053] Example 1. An electrochemical polishing method, comprising the following steps:

[0054] 1) Prepare an alkaline polishing solution with the following mass percentages: 20 wt% sodium hydroxide, 3 wt% sodium chloride (conductive salt), 2 wt% sodium nitrate, 3 wt% ethylenediamine, and the remainder deionized water. Dissolve and mix thoroughly with deionized water, then allow to cool naturally to room temperature. Set the temperature of the alkaline polishing solution to 30℃, select constant voltage electrolysis at 0.5V, and set the polishing time to 2 minutes.

[0055] 2) Prepare an acidic polishing solution with the following mass percentages: 50 wt% phosphoric acid, 30 wt% sulfuric acid, 10 wt% deionized water, 3 wt% benzotriazole, 3 wt% sodium dodecyl sulfate, and 4% citric acid. Dissolve and mix all components thoroughly, then allow to cool naturally to room temperature. Set the acidic polishing solution to 30°C, electrolyze at a constant voltage of 1V, and set the polishing time to 2 minutes.

[0056] 3) After laser processing, the pure copper sheet is first ultrasonically cleaned with anhydrous ethanol for 10 minutes, then ultrasonically cleaned with rust remover for 10 minutes, and finally ultrasonically cleaned with isopropanol for 10 minutes. Then it is dried and stored in a nitrogen cabinet.

[0057] 4) Remove the laser-cut pure copper sheet from the nitrogen chamber, perform UV activation treatment on the material surface, and then clean it in 5% dilute sulfuric acid for 3 minutes. After cleaning, rinse the fixture and material with pure water, and then place the fixture and material in an alkaline polishing solution for rough polishing.

[0058] After rough polishing, rinse the jig and material with pure water, then clean them in 10wt% dilute sulfuric acid for 3 minutes. Finally, rinse them with pure water and clean them in isopropanol for 5 minutes, then remove and blow dry. Then, place them in an acidic polishing solution for fine polishing.

[0059] After fine polishing, the fixture and material are removed together, rinsed with pure water and dried to obtain copper material with removed metal slag and low surface roughness.

[0060] Figure 1a The image shown is a micrograph of the pure copper sheet from Example 1 before polishing. Figure 1b The image shows a microscope photograph of the polished metal material. Figure 1b The photos in the image have been brightened, with the white areas representing metallic materials. Comparing the two images, it can be observed that the polished material has less molten metal on the cut surface, smoother cut edges, and fewer surface scratches.

[0061] Example 2. An electrochemical polishing method, comprising the following steps:

[0062] 1) Prepare an alkaline polishing solution with the following mass percentages: 30 wt% sodium hydroxide, 5 wt% conductive sodium chloride, 2 wt% sodium nitrate, 3 wt% ammonia, and the remainder deionized water. Dissolve and mix thoroughly with deionized water, then allow to cool naturally to room temperature. Set the temperature of the alkaline polishing solution to 40℃, select constant voltage electrolysis at 0.8V, and set the polishing time to 1 min 30 s.

[0063] 2) Prepare an acidic polishing solution with the following mass percentages: 55 wt% phosphoric acid, 30 wt% sulfuric acid, 7 wt% deionized water, 2 wt% benzotriazole, 3 wt% sodium dodecyl sulfate, and 3 wt% ethylenediaminetetraacetic acid. After thoroughly dissolving and mixing all components, allow to cool naturally to room temperature. Set the temperature of the acidic polishing solution to 30°C, perform constant voltage electrolysis at 1V, and set the polishing time to 3 minutes.

[0064] 3) After laser processing, the pure copper sheet is first ultrasonically cleaned in anhydrous ethanol for 10 minutes, then ultrasonically cleaned in rust remover for 10 minutes, and finally ultrasonically cleaned in isopropanol for 10 minutes. Then it is dried and stored in a nitrogen cabinet.

[0065] 4) Remove the laser-cut pure copper sheet from the nitrogen chamber, perform UV activation treatment on the material surface, and then clean it in 5wt% dilute sulfuric acid for 3 minutes. After cleaning, rinse the fixture and material with pure water, and then place them in an alkaline polishing solution for rough polishing. After rough polishing, rinse the fixture and material with pure water, then clean them in 10wt% dilute sulfuric acid for 3 minutes. Finally, remove them, rinse them with pure water, and then clean them in isopropanol for 5 minutes. Remove them and blow them dry. Then, place them in an acidic polishing solution for fine polishing. After fine polishing, remove the fixture and material together, rinse them with pure water, and blow them dry to obtain copper material with removed metal slag and low surface roughness.

[0066] Figure 2a The image shown is a microscopic photograph of the pure copper sheet before polishing in Example 2. Figure 2b The images show microscopic photographs of polished metal materials. Comparing the two images, it can be seen that the cut edges of the polished metal material are smoother and surface scratches are reduced.

[0067] Example 3. An electrochemical polishing method, comprising the following steps:

[0068] 1) Prepare an alkaline polishing solution with the following mass percentages: 30 wt% sodium hydroxide, 5 wt% conductive sodium chloride, 3 wt% sodium nitrate, 3 wt% ammonia, and the remainder deionized water. Dissolve and mix thoroughly with deionized water, then allow to cool naturally to room temperature. Set the temperature of the alkaline polishing solution to 50℃, select constant voltage electrolysis at 0.8V, and set the polishing time to 1 minute.

[0069] 2) Prepare an acidic polishing solution with the following mass percentages: 60 wt% phosphoric acid, 25 wt% sulfuric acid, 5 wt% deionized water, 3 wt% sodium nitrate, 3 wt% thiourea, and 4 wt% citric acid. After thorough dissolution and mixing, allow to cool naturally to room temperature. Set the acidic polishing solution temperature to 40℃, electrolyze at a constant voltage of 0.8V, and set the polishing time to 2 minutes.

[0070] 3) After laser processing, the pure copper sheet is first ultrasonically cleaned in anhydrous ethanol for 10 minutes, then ultrasonically cleaned with a rust remover for 10 minutes, and finally ultrasonically cleaned with isopropanol for 10 minutes. Then it is dried and stored in a nitrogen cabinet.

[0071] 4) Remove the laser-cut pure copper sheet from the nitrogen chamber, perform UV activation treatment on the material surface, and then clean it in 5wt% dilute sulfuric acid for 3 minutes. After cleaning, rinse the fixture and material with pure water, and then place them in an alkaline polishing solution for rough polishing. After rough polishing, rinse the fixture and material with pure water, then clean them in 10wt% dilute sulfuric acid for 3 minutes. Finally, remove them, rinse them with pure water, and then clean them in isopropanol for 5 minutes. Remove them and blow them dry. Then, place them in an acidic polishing solution for fine polishing. After fine polishing, remove the fixture and material together, rinse them with pure water, and blow them dry to obtain copper or copper alloy material with removed metal slag and low surface roughness.

[0072] Figure 3a The image shown is a microscopic photograph of the pure copper sheet before polishing in Example 3. Figure 3b The image shows a microscope photograph of a polished pure copper sheet. Comparing the two images, it can be seen that the cut edges of the polished metal material are smooth and contain less molten metal.

[0073] Comparative Example

[0074] The existing electrochemical polishing method includes the following steps:

[0075] 1) Prepare the polishing solution by mixing the following components: 100g phosphoric acid, 25g sulfuric acid, 5g hydrochloric acid, 10g polyethylene glycol, 5g glycerol, 2g tributyl phosphate, and 30g deionized water. Set the temperature of the polishing solution to 40℃, use a constant voltage electrolysis at 0.8V, and set the polishing time to 2 minutes.

[0076] 2) After laser processing, the pure copper sheet is first ultrasonically cleaned with anhydrous ethanol for 10 minutes, then ultrasonically cleaned with rust remover for 10 minutes, and finally ultrasonically cleaned with isopropanol for 10 minutes. Then it is dried and stored in a nitrogen cabinet.

[0077] 3) Remove the laser-cut pure copper sheet from the nitrogen chamber, perform UV activation treatment on the material surface, and then clean it in 5wt% dilute sulfuric acid for 3 minutes. After cleaning, rinse the fixture and material with pure water, then place the fixture and material in the above polishing solution for polishing. After polishing, rinse the fixture and material with pure water, then clean it in 10wt% dilute sulfuric acid for 3 minutes. Finally, remove it, rinse it with pure water, and then clean it in isopropanol for 5 minutes. Remove it and blow it dry.

[0078] Figure 4 The image shows a microscopic photograph of the polished copper alloy in the comparative example. It can be seen from the image that there are obvious burrs on the cut edge of the metal material, and the slag on the edge after cutting has not been completely removed.

[0079] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope. The scope of protection of the present invention is defined by the appended claims, specification, and their equivalents.

Claims

1. An electrochemical polishing solution for copper and copper alloys, characterized in that, The polishing agent includes alkaline polishing agents and acidic polishing agents. The alkaline polishing agent, by weight percentage, comprises: 20%-50% sodium hydroxide or potassium hydroxide, 1%-10% conductive salt, 1%-5% sodium nitrate, 1%-10% copper ion complexing agent, and the remainder being deionized water. The acidic polishing agent, by weight percentage, comprises: 50%-65% phosphoric acid, 20%-35% sulfuric acid, 1%-5% corrosion inhibitor, 1%-3% brightener, and 1%-5% copper ion complexing agent, and the remainder being deionized water.

2. The electrochemical polishing solution according to claim 1, characterized in that: The copper ion complexing agent in the alkaline polishing agent is ethylenediamine, ethylenediaminetetraacetic acid, or ammonia, and the conductive salt is sodium chloride or potassium chloride.

3. The electrochemical polishing solution according to claim 1, characterized in that: The copper ion complexing agent in the acidic polishing agent is citric acid, phosphonate, or ethylenediaminetetraacetic acid; the brightener is sodium dodecyl sulfate, thiourea, or polyethylene glycol; and the corrosion inhibitor is benzotriazole, triphenyltetraazole chloride, or sodium nitrate.

4. A polishing method using the electrochemical polishing solution as described in any one of claims 1-3, characterized in that, The copper or pure copper sheet is first placed in the alkaline polishing agent for rough polishing, and then the rough polished material is placed in the acidic polishing agent for fine polishing.

5. The electrochemical polishing method according to claim 4, characterized in that, Includes the following steps: S1. Perform preliminary surface cleaning on the laser-processed copper or pure copper sheet; S2. Perform UV activation treatment on the surface of the pre-cleaned copper or pure copper sheet; S3. Place the activated copper or pure copper sheet in the alkaline polishing agent for the first step of rough polishing; S4. Place the roughly polished copper or pure copper sheet in an acidic polishing agent for fine polishing.

6. The electrochemical polishing method according to claim 5, characterized in that: In step S1, the copper or pure copper sheet to be polished is placed in anhydrous ethanol for ultrasonic cleaning for 5-30 minutes, in a rust remover for ultrasonic cleaning for 5-30 minutes, and in isopropanol for ultrasonic cleaning for 5-30 minutes, and then dried for later use.

7. The electrochemical polishing method according to claim 5, characterized in that: Step S2 further includes cleaning the UV-activated copper or pure copper sheet in 5% dilute sulfuric acid.

8. The electrochemical polishing method according to claim 5, characterized in that: In step S3, the voltage range selected for polishing is between 0.5-1.8V, and the temperature of the alkaline polishing solution is maintained between 20-35°C.

9. The electrochemical polishing method according to claim 5, characterized in that: In step S4, the voltage range selected for polishing is between 0.2 and 1.2V, and the temperature of the acidic polishing solution is maintained between 30 and 50°C.

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