System and method for reducing use amount of TFT-LCD copper etching liquid

Abstract

The invention relates to a system and a method for reducing the use amount of a TFT-LCD copper etching solution, and the method comprises the following steps: extracting a copper-containing etching waste solution through a mixed extraction agent, removing copper ions and other metal ions by adopting a multi-stage countercurrent or cross-current extraction mode, and separating to obtain a copper-loaded organic phase and a copper etching solution regeneration crude solution; treating the regenerated crude liquid through a hydrophobic porous adsorbent to remove the residual extractant, so as to obtain regenerated etching liquid; and finally, performing component blending on the regenerated etching liquid, including supplementing hydrogen peroxide and fluorine ions or mixing the regenerated etching liquid with a new copper etching liquid to obtain a recyclable etching liquid, and returning the recyclable etching liquid to an etching system. And after the copper-loaded organic phase is subjected to acid back extraction, metal copper can be recovered, and the extraction agent is recycled. According to the invention, the usage amount of the copper etching liquid can be obviously reduced, the service life can be prolonged, the manufacturing cost can be reduced, the explosion risk caused by copper ion accumulation can be avoided, and the method is suitable for the copper and copper / other metal multi-film layer etching process in the fields of TFT-LCD (Thin Film Transistor Liquid Crystal Display) and semiconductors.

Description

Technical Field

[0001] This invention relates to the field of waste liquid resource utilization technology, and more specifically, to a system and method for reducing the amount of copper etching solution used in TFT-LCDs. Background Technology

[0002] With the rapid development of the TFT-LCD (Thin Film Transistor Liquid Crystal Display) industry, the treatment and regeneration of copper-containing etching wastewater generated during its manufacturing process has become increasingly prominent. Copper etching is a critical process step in TFT-LCD manufacturing, typically using an etching solution containing hydrogen peroxide to pattern the copper layer. However, as the etching process progresses, the concentration of copper ions in the etching solution continuously increases, leading to a decrease in etching efficiency and causing environmental pollution and resource waste.

[0003] Currently, various technical solutions exist in the industry for the treatment and regeneration of copper-containing etching wastewater. For example, Chinese patent application CN105506636A discloses a recycling system and method for extracting copper-containing wastewater. This system includes an extraction tank, a washing tank, a circulation tank, a back-extraction tank, and an electrolysis system. It improves the copper extraction rate through a dual washing process and incorporates a stirring separation chamber to enhance separation efficiency. Chinese patent application CN110144590A proposes a regeneration system for alkaline copper-containing etching wastewater and ammonia nitrogen wastewater recycling. This system achieves copper recovery and ammonia nitrogen wastewater recycling by mixing alkaline copper-containing etching wastewater with an extractant. Chinese patent application CN211339693U also discloses a system for regenerating alkaline copper-containing etching waste liquid and recycling ammonia nitrogen wastewater, including an extraction device, a washing device, a back-extraction device, and an electrolysis device, which can efficiently recover copper from alkaline copper-containing etching waste liquid. In addition, Chinese patent application CN205529043U describes a recycling system for extracting copper-containing waste liquid. This system improves the copper extraction rate through a double washing process and improves the separation efficiency by setting up a stirring separation chamber, realizing the recycling of etching liquid and residual liquid. Chinese patent CN114606497B discloses a process for treating and recycling ferric chloride etching liquid. This method does not introduce any oxidant, which can greatly reduce costs, and does not generate chlorine gas during electrolysis, thus avoiding safety hazards. However, existing extraction systems often lack targeted design when treating specific copper etching liquids for TFT-LCDs, and cannot effectively solve the safety hazard of hydrogen peroxide self-decomposition. At the same time, existing systems have shortcomings in the design of the washing stage, making it difficult to achieve efficient oil phase purification and separation of metal concentrates. Furthermore, the existing back-extraction tank structure design is not reasonable enough, which easily leads to crystallization blockage and affects the long-term stable operation of the system. Japanese patent application JPH08311664A discloses an extraction and regeneration method suitable for ammoniacal copper chloride etching solution, but it has the following shortcomings: it is only for alkaline etching systems and is difficult to apply to acidic copper etching solutions; sulfate ions are easily left in the extractant after back-extraction, which leads to the accumulation of sulfate in the etching solution system and affects the etching rate and stability; at the same time, complex cleaning steps are required to remove residual sulfate ions, making the process cumbersome and the long-term operating stability of the system insufficient.

[0004] Furthermore, existing technologies still present several challenges in regenerating and recycling copper etching solutions for TFT-LCDs: Firstly, with the increasing size of TFT-LCDs, the amount of etching solution used in wet etching is growing significantly, substantially increasing manufacturing costs. Secondly, mainstream etching solutions contain hydrogen peroxide, and as etching progresses, the increasing copper ion concentration catalyzes the self-decomposition of hydrogen peroxide, posing a potential explosion risk. Thirdly, the increased copper ion concentration in the etching solution leads to poor etching characteristics, affecting product quality. Additionally, existing methods for increasing etching lifespan by adding etching additives or auxiliaries require continuous replenishment, increasing process complexity and operational difficulty.

[0005] Therefore, there is an urgent need to develop a system and method to reduce the amount of copper etching solution used in TFT-LCDs, which can effectively solve the above-mentioned technical problems, achieve efficient regeneration and recycling of the etching solution, reduce manufacturing costs, eliminate safety hazards, and maintain good etching characteristics. Summary of the Invention

[0006] One of the technical problems to be solved by the present invention is to provide a method for reducing the amount of copper etching solution used in TFT-LCDs, so as to solve the problems in the prior art that lead to abnormal etching rate due to copper ion concentration accumulation, explosion risk caused by hydrogen peroxide self-decomposition, short service life of etching solution, high cost, and residual extractant affecting precision etching.

[0007] To overcome the shortcomings of the prior art, the present invention provides a method for reducing the amount of copper etching solution used in TFT-LCDs, comprising the following steps: S1: The copper-containing etching waste liquid is transferred to the extraction system, and extraction is performed by adding a mixed extractant. Multi-stage countercurrent / cross-current extraction is carried out to reduce the concentration of copper ions and other metal ions in the waste liquid, and the copper-loaded organic phase is separated to obtain copper etching solution regeneration crude solution; wherein, the mixed extractant includes a diluent and one or more of the following components in combination: P204 extractant, TBP extractant, Lix984 extractant, N235 extractant; S2: The regenerated crude solution is treated with a hydrophobic porous adsorbent to remove residual extractant, thus obtaining the regenerated etching solution; S3: After further adjusting the composition of the regenerated etching solution, it is returned to the etching system for recycling.

[0008] This application presents a method for reducing the amount of copper etching solution used in TFT-LCDs. Compared with existing technologies, this method has the following advantages: It replaces the existing method of extending the lifespan by simply adding etching additives with a three-stage process: "extracting copper ions with a mixed extractant + removing extractant residue with a hydrophobic adsorbent + supplementing active components through component adjustment." Extractants such as P2O4 and TBP are used to complex copper ions, and a diluent is used to reduce the system viscosity and improve extraction efficiency. Deep copper removal is achieved through multi-stage countercurrent or cross-current operations. Hydrophobic porous adsorbents are then used to remove extractant residue, avoiding any impact on etching precision. Finally, hydrogen peroxide and fluoride ions are added, or the solution is mixed with fresh solution in a specific ratio to restore the etching solution composition, ensuring stable performance for repeated use. This forms a systematic solution from copper removal, extraction, and formulation to recycling, significantly reducing the consumption of copper etching solution. This invention achieves the technical effects of reducing copper etching solution usage, extending service life, reducing manufacturing costs, eliminating explosion hazards, and maintaining etching quality, completely solving the problems of copper ion accumulation, complex processes, and safety risks in the prior art. The method adopted by this invention is applicable to mixed extractant formulations and multi-stage countercurrent / crosscurrent extraction processes, overcoming the limitation of prior art which is only applicable to alkaline systems. Simultaneously, the use of hydrophobic porous adsorbents effectively removes residual extractant from the regenerated solution, avoiding the accumulation of impurity ions introduced into the system by the extractant and back-extraction process, thus simplifying the cleaning operation. Furthermore, by adjusting the composition of the regenerated etching solution, this invention ensures the stability of the etching solution composition, achieving a simple process flow, long operating cycle, and high system stability, meeting the stringent requirements of the TFT-LCD industry for etching solution quality and safety.

[0009] In one possible implementation, in step S1, the copper ion concentration of the copper-containing etching waste liquid is above 2000 ppm; in step S2, the copper ion concentration of the regenerated etching solution is 300-500 ppm.

[0010] Compared with existing technologies, the above technical solution effectively utilizes the extractant capacity and ensures economic efficiency by starting extraction when the copper ion concentration reaches 2000 ppm or higher. At the same time, controlling the copper ion concentration of the regenerated etching solution at 300-500 ppm can significantly reduce the copper ion concentration in the system and avoid the side reaction of catalyzing the self-decomposition of hydrogen peroxide.

[0011] In one possible implementation, the mixed extractant comprises a diluent and a combination of one or more of the following components: phosphorus-containing extractant, nitrogen-containing extractant, oxime-containing extractant, and sulfur-containing extractant.

[0012] In one possible implementation, in step S1, the mixed extractant is obtained by mixing P204, TBP, and a diluent, and the volume ratio of P204, TBP, and the diluent is 2:1:7.

[0013] Compared with existing technologies, the above technical solution utilizes P204's excellent complexing and extraction capabilities for copper ions, TBP as a phase transfer catalyst to improve extraction selectivity and stability, and a diluent to dilute the system viscosity and improve phase separation. The three components are mixed in a 2:1:7 ratio to achieve optimal synergistic effects, thereby improving extraction efficiency, reducing operating viscosity, and accelerating phase separation. Ultimately, this achieves the effects of rapid copper removal, avoiding emulsification, improving the quality of the regenerated solution, and enhancing the stability of continuous system operation.

[0014] In one possible implementation, the diluent is a hydrocarbon compound, more preferably sulfonated kerosene.

[0015] Compared with existing technologies, the direct technical principle of the above technical solution is that sulfonated kerosene, as a diluent, has excellent chemical stability, low viscosity, and high compatibility with P2O4 and TBP. It can effectively dilute the extraction system, reduce interfacial tension, improve the fluidity and phase separation efficiency of the extraction system, avoid emulsification, and improve the technical effect of continuous operation, stability and overall copper removal rate of multi-stage extraction.

[0016] In one possible implementation, in step S2, the adsorbent is selected from at least one of graphite sheets, porous resins, MOFs, and COFs.

[0017] Compared with existing technologies, the above technical solution uses graphite sheets, porous resins, metal-organic frameworks (MOFs) or covalent organic frameworks (COFs) with hydrophobicity and high specific surface area as adsorbents. By utilizing their physical adsorption and selective retention capabilities for organic phase extractant molecules, the residual extractant in the regenerated crude solution is effectively removed. The direct technical effect is to prevent extractant residue from entering the subsequent etching process, thus avoiding adverse effects on etching performance and pattern accuracy.

[0018] In one possible implementation, step S3, further adjusting the composition of the regenerated etching solution, includes: adding hydrogen peroxide and / or fluoride ions to the regenerated etching solution, or adding a new copper etching solution to the regenerated etching solution, and / or extracting molybdenum ions from the regenerated etching solution using N235 extractant.

[0019] Compared with existing technologies, the above technical solution, by selectively adjusting the regenerated etching solution in step S3 according to actual needs through various component adjustments, including adding hydrogen peroxide and / or fluoride ions, can effectively restore the oxidizing properties and etching selectivity of the etching solution and maintain the stability of the process window. By adding new copper etching solution to the regenerated etching solution, the solution concentration and chemical ratio can be quickly adjusted to ensure that the etching performance meets the process requirements and simplify the operation process. Furthermore, by using N235 extractant to extract molybdenum ions in the regenerated etching solution, accumulated metal impurities such as molybdenum can be removed, preventing them from depositing or affecting the film quality during subsequent etching processes, thereby improving the purity and stability of the etching solution. The above solutions can be used individually to solve specific problems or combined to synergistically optimize the performance of the etching solution. Ultimately, this achieves stable multi-cycle use of the etching solution, extends its lifespan, reduces usage and waste discharge, lowers manufacturing costs, and significantly improves the reliability and yield of TFT-LCD and copper / molybdenum multi-film micro-pattern manufacturing.

[0020] In one possible implementation, the conditions for adding hydrogen peroxide are: the volume ratio of the new copper etching solution to the regenerated etching solution is 1:1; and the conditions for replenishing hydrogen peroxide are: the concentration of hydrogen peroxide added to the regenerated etching solution is 18-22 wt%.

[0021] Compared with existing technologies, the above technical solution ensures the optimal balance between component concentration and reactivity by mixing the new copper etching solution and the regenerated etching solution in a 1:1 ratio. At the same time, the hydrogen peroxide concentration is replenished to 18-22 wt% to maintain the oxidation capacity of the solution within a stable range. By precisely proportioning the solutions, the etching reaction rate and liquid phase stability are maintained, avoiding insufficient etching or over-corrosion, ensuring product consistency and reliability, and achieving the effects of improving etching yield, extending the service life of the etching solution, and reducing operating costs.

[0022] In one possible implementation, step S1 further includes a back-extraction operation on the copper-loaded organic phase: the copper-loaded organic phase is mixed with an acid solution for back-extraction to obtain a copper-containing solution and a regenerated extractant, which is then recycled back into step S1.

[0023] Compared with existing technologies, the above technical solution involves back-extraction of the copper-loaded organic phase after extraction. This utilizes the exchange reaction between protons in the acid solution and copper ions coordinated with the extractant to transfer copper ions to the aqueous phase, resulting in a soluble copper-containing solution. Simultaneously, the organic phase extractant is regenerated, achieving the recycling of the extractant, reducing extractant consumption, lowering operating costs, and achieving continuous and stable system operation, improved copper recovery rate, and enhanced production economics.

[0024] In one possible implementation, the acid is sulfuric acid, the copper-containing solution is copper sulfate solution, and the copper sulfate solution is electrolyzed to recover metallic copper and sulfuric acid, the sulfuric acid being returned to step S1 for back-extraction.

[0025] Compared with existing technologies, the above-mentioned technical solution utilizes sulfuric acid to back-extract a copper-loaded organic phase to generate a copper sulfate solution, and then uses electrolysis to reduce copper ions to metallic copper at the cathode. At the same time, the sulfuric acid generated in the anode area can be recycled back to the back-extraction process, achieving efficient recovery of metallic copper and closed-loop recycling of sulfuric acid. It also reduces acid consumption, lowers wastewater discharge, and improves resource utilization and environmental and economic efficiency.

[0026] Another technical problem to be solved by the present invention is to provide a system for reducing the amount of copper etching solution used in TFT-LCDs, so as to solve the problems of low recycling rate of copper etching solution, difficulty in reusing extractant, poor process stability and high processing cost in the prior art.

[0027] To overcome the shortcomings of the prior art, the present invention provides a system for reducing the amount of copper etching solution used in TFT-LCDs. The system is used to implement the method and includes: Extraction unit: used for multi-stage extraction of copper-containing etching waste liquid to separate the copper-loaded organic phase and the regenerated crude liquid; Adsorption unit: connected to the extraction unit, used to remove residual extractant from the regenerated crude liquid; Preparation unit: connected to the adsorption unit, used to replenish components to the regenerated etching solution or mix new solution; Back-extraction electrolysis unit: connected to the extraction unit, used to process the copper-loaded organic phase, output regenerated extractant to the extraction unit, and recover metallic copper.

[0028] Compared with the prior art, the system for reducing the amount of copper etching solution used in TFT-LCD proposed in this application has the following advantages: The system of the present invention changes the "single extraction and recovery system for PCB copper waste liquid only" in the prior art to a "multi-stage extraction-removal-blending-back-extraction electrolysis closed-loop integrated system applicable to TFT-LCD copper etching solution". The extraction unit selectively removes copper ions and other metal ions, the adsorption unit removes residual extractant to ensure the purity of the etching solution, the blending unit replenishes consumed components or new solution to maintain the optimal etching formula, and the back-extraction electrolysis unit back-extracts and electrolyzes the copper-loaded organic phase, realizing the simultaneous recovery of metallic copper and extractant. The process involves recycling and regenerating the etching solution, significantly reducing the amount of copper etching solution used and the consumption of new solution, reducing waste liquid discharge, improving copper recovery rate, and lowering overall production costs. These four modules are interconnected, forming a "closed-loop process chain for the recycling of TFT-LCD copper etching solution." This not only meets the requirements for protecting the recycling rate of etching solution and process safety, but also further solves the problems in the background technology, such as the residual extractant in the raffinate affecting the etching quality, the lack of a back-extraction closed loop leading to high extractant costs, and poor overall process stability. Ultimately, this achieves green manufacturing of TFT-LCD etching solution and improves economic benefits. Attached Figure Description

[0029] Figure 1 This is a flowchart illustrating the principle of the present invention. Detailed Implementation

[0030] First, those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the embodiments of this application and are not intended to limit the scope of protection of the embodiments of this application. Those skilled in the art can make adjustments as needed to adapt to specific application scenarios.

[0031] This invention provides a method for reducing the amount of copper etching solution used in TFT-LCDs, such as... Figure 1 As shown, Figure 1 The flowchart of this invention includes the following steps: S1: The copper-containing etching waste liquid is transferred to the extraction system, and extraction is performed by adding a mixed extractant. Multi-stage countercurrent / cross-current extraction is carried out to reduce the concentration of copper ions and other metal ions in the waste liquid, and the copper-loaded organic phase is separated to obtain copper etching solution regeneration crude solution; wherein, the mixed extractant includes a diluent and one or more of the following components in combination: P204 extractant, TBP extractant, Lix984 extractant, N235 extractant; S2: The regenerated crude solution is treated with a hydrophobic porous adsorbent to remove residual extractant, thus obtaining the regenerated etching solution; S3: After further adjusting the composition of the regenerated etching solution, it is returned to the etching system for recycling.

[0032] As a preferred embodiment, in step S1, the copper ion concentration of the copper-containing etching waste liquid is above 2000 ppm; in step S2, the copper ion concentration of the regenerated etching solution is 300-500 ppm.

[0033] As a preferred embodiment, the mixed extractant includes a diluent and a combination of one or more of the following components: phosphorus-containing extractant, nitrogen-containing extractant, oxime-containing extractant, and sulfur-containing extractant.

[0034] As a preferred embodiment, in step S1, the mixed extractant is obtained by mixing P204, TBP, and a diluent, and the volume ratio of P204, TBP, and the diluent is 2:1:7.

[0035] As a preferred embodiment, the diluent is a hydrocarbon compound, and more preferably, sulfonated kerosene.

[0036] As a preferred embodiment, in step S2, the adsorbent is selected from at least one of graphite sheets, porous resins, MOFs, and COFs.

[0037] As a preferred embodiment, in step S3, the method of further adjusting the composition of the regenerated etching solution includes: adding hydrogen peroxide and / or fluoride ions to the regenerated etching solution, or adding a new copper etching solution to the regenerated etching solution; and extracting molybdenum ions from the regenerated etching solution using N235 extractant.

[0038] As a preferred embodiment, the conditions for adding hydrogen peroxide are: the volume ratio of the new copper etching solution to the regenerated etching solution is 1:1; and the conditions for replenishing hydrogen peroxide are: the concentration of hydrogen peroxide added to the regenerated etching solution is 18-22 wt%.

[0039] As a preferred embodiment, step S1 further includes a back-extraction operation on the copper-loaded organic phase: the copper-loaded organic phase is mixed with acid solution for back-extraction to obtain a copper-containing solution and a regenerated extractant, which is then recycled back into step S1.

[0040] As a preferred embodiment, the acid solution is sulfuric acid, the copper-containing solution is copper sulfate solution, and the copper sulfate solution is electrolyzed to recover metallic copper and sulfuric acid, the sulfuric acid being returned to step S1 for back-extraction.

[0041] The present invention also provides a system for reducing the amount of copper etching solution used in TFT-LCDs, the system being used to implement the method, the system comprising: Extraction unit: used for multi-stage extraction of copper-containing etching waste liquid to separate the copper-loaded organic phase and the regenerated crude liquid; Adsorption unit: connected to the extraction unit, used to remove residual extractant from the regenerated crude liquid; Preparation unit: connected to the adsorption unit, used to replenish components to the regenerated etching solution or mix new solution; Back-extraction electrolysis unit: connected to the extraction unit, used to process the copper-loaded organic phase, output regenerated extractant to the extraction unit, and recover metallic copper.

[0042] The following will further explain the technical solution of the present invention in conjunction with embodiments including specific experimental data: Example 1: This embodiment provides a system and method for reducing the amount of copper etching solution used in TFT-LCDs, the system comprising: Extraction unit: used for multi-stage extraction of copper-containing etching waste liquid to separate the copper-loaded organic phase and the regenerated crude liquid; Adsorption unit: connected to the extraction unit, used to remove residual extractant from the regenerated crude liquid; Preparation unit: connected to the adsorption unit, used to replenish components to the regenerated etching solution or mix new solution; Back-extraction electrolysis unit: connected to the extraction unit, used to process the copper-loaded organic phase, output regenerated extractant to the extraction unit, and recover metallic copper.

[0043] The method includes the following steps: S1: Extraction process: The copper-molybdenum etching solution, consisting of 20% hydrogen peroxide, 3% iminodiacetic acid, 0.1% 5-amino-4-azine, 0.5% sodium fluoride, and 1% sulfuric acid, resulted in a copper ion concentration of 2000 ppm after etching the copper / molybdenum film. This copper-containing etching waste liquid was then transferred to an extraction system. A mixed extractant, consisting of P2O4, TBP, and sulfonated kerosene in a volume ratio of 2:1:7, was used for multi-stage countercurrent extraction to reduce the copper ion concentration in the etching solution. After extraction, the copper ion concentration was reduced to 300 ppm, and the copper-loaded organic phase and the copper etching solution regeneration crude solution were separated. S2: De-extraction treatment: The regenerated crude solution is treated with a hydrophobic porous adsorbent to remove residual extractant, thereby obtaining a regenerated etching solution, wherein the adsorbent is MOF; S3: Ingredient formulation and recycling: Based on the requirements of the etching solution composition, the regenerated etching solution is adjusted to add necessary components (such as hydrogen peroxide and / or fluoride ions), and then returned to the etching system for recycling. The performance evaluation results of etching using the recycled etching solution are shown in Table 1.

[0044] Example 2: Example 2 provides a system and method for reducing the amount of copper etching solution used in TFT-LCDs. The system is the same as that in Example 1, and the method includes the following steps: S1: Extraction process: A copper-molybdenum etching solution, comprising 20% ​​hydrogen peroxide, 3% iminodiacetic acid, 0.1% 5-amino-4-azolium, 0.5% sodium fluoride, and 1% sulfuric acid, was used to etch a copper / molybdenum film until the copper ion concentration reached 5000 ppm. This copper-containing etching waste liquid was then transferred to an extraction system, where a mixed extractant was added. This mixed extractant was prepared by mixing P204 extractant, TBP extractant, and sulfonated kerosene diluent in a volume ratio of 2:1:7. A multi-stage cross-flow extraction process was used to remove copper ions and other metal ions from the waste liquid, separating the copper-loaded organic phase to obtain a copper etching solution regenerated crude solution. After extraction, the copper ion concentration in the regenerated crude solution was reduced to 500 ppm.

[0045] S2: De-extraction treatment: The obtained regenerated crude liquid is treated with a hydrophobic porous adsorbent to remove residual extractant, thereby obtaining a regenerated etching solution. The adsorbent is a porous resin.

[0046] S3: Ingredient formulation and recycling: The above-mentioned recycled etching solution is mixed with the new copper-molybdenum etching solution at a volume ratio of 1:1 to form a recyclable etching solution, which is then returned to the etching system to continue the etching process. The performance test results after etching evaluation are shown in Table 1.

[0047] Example 3: Example 3 provides a system and method for reducing the amount of copper etching solution used in TFT-LCDs. The system is the same as that in Example 1, and the method includes the following steps: S1: Extraction process: A copper-molybdenum etching solution, comprising 20% ​​hydrogen peroxide, 3% iminodiacetic acid, 0.1% 5-amino-4-azolium, 0.5% sodium fluoride, and 1% sulfuric acid, was used to etch a copper / molybdenum film until the copper ion concentration reached 5000 ppm. This copper-containing etching waste liquid was then transferred to an extraction system, where a mixed extractant was added. This mixed extractant was prepared by mixing P204 extractant, TBP extractant, and sulfonated kerosene diluent in a volume ratio of 2:1:7. A multi-stage countercurrent extraction method was used to remove copper ions and other metal ions from the waste liquid, separating a copper-loaded organic phase. The copper ion concentration in the regenerated crude copper etching solution was reduced to 500 ppm.

[0048] S2: De-extraction treatment: The regenerated crude solution is treated with a hydrophobic porous adsorbent to remove residual extractant, thereby obtaining a regenerated etching solution. The adsorbent is COF.

[0049] S3: Ingredient formulation and recycling: Hydrogen peroxide is added to the above-mentioned regenerated etching solution to restore the hydrogen peroxide concentration to 20%, resulting in a recyclable etching solution, which is then returned to the etching system to continue the etching process.

[0050] The performance test results after etching evaluation are shown in Table 1.

[0051] Example 4: Example 4 provides a system and method for reducing the amount of copper etching solution used in TFT-LCDs. The system is the same as that in Example 1, and the method includes the following steps: S1: Extraction process: A copper-molybdenum etching solution, comprising 20% ​​hydrogen peroxide, 3% iminodiacetic acid, 0.1% 5-amino-4-azine, 0.5% sodium fluoride, and 1% sulfuric acid, was used to etch a copper / molybdenum film until the copper ion concentration reached 2000 ppm. This copper-containing etching waste liquid was then transferred to an extraction system, where a mixed extractant was added. This mixed extractant was prepared by mixing P204 extractant, TBP extractant, and sulfonated kerosene diluent in a volume ratio of 2:1:7. Multi-stage countercurrent extraction was employed to remove copper ions and other metal ions from the waste liquid, separating a copper-loaded organic phase from the copper etching solution regeneration crude solution, reducing the copper ion concentration to 300 ppm.

[0052] S2: De-extraction treatment: The obtained regenerated crude solution is treated with a hydrophobic porous adsorbent to remove the residual extractant, resulting in a regenerated etching solution. The adsorbent is a graphite sheet.

[0053] S3: Further metal removal and recycling: The regenerated etching solution is further treated with N235 extractant to extract molybdenum ions, thereby removing the molybdenum metal ions. The treated regenerated etching solution is then returned to the etching system for recycling.

[0054] The performance test results after etching evaluation are shown in Table 1.

[0055] Table 1: The above embodiments further demonstrate that after regenerating the TFT-LCD copper etching solution using the method of the present invention, the etching rate (EPD), critical size deviation (Cd bias), and sidewall taper angle of the etching solution remain consistent with or change controllably with the original solution. This indicates that the regenerated etching solution still possesses good process adaptability, meets the stringent requirements for morphology control and precision in the etching process, and exhibits no significant process degradation. The present invention first utilizes a mixed extractant composed of P204, TBP, and sulfonated kerosene to selectively remove copper ions and other metal ions through a multi-stage countercurrent or cross-current extraction process, reducing the copper ion concentration in the waste liquid. Then, a hydrophobic porous adsorbent is used to remove residual extractant from the regenerated crude solution, ensuring the purity and stability of the regenerated etching solution. Subsequently, through component adjustment… By adding hydrogen peroxide, fluoride ions, or mixing with fresh copper etching solution, the optimal composition ratio of the etching solution is restored. Finally, the treated regenerated etching solution is returned to the etching system for recycling. This invention not only solves the risk of hydrogen peroxide self-decomposition and explosion caused by copper ion accumulation and the problem of etching solution waste in existing technologies, but also significantly extends the service life of the etching solution, reduces the amount of fresh solution used, lowers production costs, and avoids the impact of extractant residue on subsequent etching quality. This ensures process stability and product yield, meeting the high purity, low cost, and safety requirements of the TFT-LCD and semiconductor industries for the recycling of etching solutions.

[0056] In the description of this application, the references to terms such as "an embodiment," "some embodiments," "in this embodiment," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0057] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for reducing the amount of copper etching solution used in TFT-LCDs, characterized in that, Includes the following steps: S1: The copper-containing etching solution is transferred to the extraction system and extracted by adding a mixed extractant. Single-stage or multi-stage countercurrent / cross-current extraction is performed to reduce the concentration of copper ions and other metal ions in the waste liquid, and the copper-loaded organic phase is separated to obtain the copper etching solution regeneration crude solution. S2: The regenerated crude solution is treated with an adsorbent to remove residual extractant, resulting in a regenerated etching solution; S3: After further adjusting the composition of the regenerated etching solution, it is returned to the etching system for recycling.

2. The method for reducing the amount of copper etching solution used in TFT-LCD according to claim 1, characterized in that, In step S1, the copper ion concentration of the copper-containing etching waste liquid is above 300 ppm.

3. The method for reducing the amount of copper etching solution used in TFT-LCD according to claim 1, characterized in that, In step S1, the mixed extractant includes a diluent and a combination of one or more of the following components: phosphorus-containing extractant, nitrogen-containing extractant, oxime-containing extractant, and sulfur-containing extractant.

4. The method for reducing the amount of copper etching solution used in TFT-LCD according to claim 3, characterized in that, The mixed extractant is obtained by mixing P204, TBP and diluent, and the volume ratio of P204, TBP and diluent is 2:1:

7.

5. The method for reducing the amount of copper etching solution used in TFT-LCD according to claim 3, characterized in that, The diluent is a hydrocarbon compound.

6. The method for reducing the amount of copper etching solution used in TFT-LCD according to claim 1, characterized in that, Step S1 also includes a back-extraction operation on the copper-loaded organic phase: the copper-loaded organic phase is mixed with acid solution for back-extraction to obtain a copper-containing solution and a regenerated extractant, which is then returned to step S1 for recycling.

7. The method for reducing the amount of copper etching solution used in TFT-LCD according to claim 6, characterized in that, The acid solution is sulfuric acid, the copper-containing solution is copper sulfate solution, and the copper sulfate solution is electrolyzed to recover metallic copper and sulfuric acid. The sulfuric acid is used to return to step S1 for back-extraction.

8. The method for reducing the amount of copper etching solution used in TFT-LCD according to claim 1, characterized in that, In step S2, the adsorbent is selected from at least one of graphite sheets, porous resins, MOFs, and COFs.

9. The method for reducing the amount of copper etching solution used in TFT-LCD according to claim 1, characterized in that, In step S3, the method of further adjusting the composition of the regenerated etching solution includes: adding hydrogen peroxide and / or fluoride ions to the regenerated etching solution, or adding a new copper etching solution to the regenerated etching solution, and / or extracting molybdenum ions from the regenerated etching solution using an extractant.

10. A system for reducing the amount of copper etching solution used in TFT-LCDs, characterized in that, The system is used to implement the method according to any one of claims 1-9, the system comprising: Extraction unit: used for single-stage or multi-stage extraction of copper-containing etching waste liquid to separate the copper-loaded organic phase and the regenerated crude liquid; Adsorption unit: connected to the extraction unit, used to remove residual extractant from the regenerated crude liquid; Preparation unit: connected to the adsorption unit, used to replenish components to the regenerated etching solution or mix new solution; Back-extraction electrolysis unit: connected to the extraction unit, used to process the copper-loaded organic phase, output regenerated extractant to the extraction unit, and recover metallic copper.

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