A highly stable and long-life copper-titanium etching solution and its preparation method and application

Abstract

The present invention belongs to the technical field of etching solutions, and specifically relates to a highly stable and long-life copper-titanium etching solution, its preparation method, and application. The copper-titanium etching solution is obtained by mixing persulfate, organic acid, sulfonated cyclodextrin, acidic ionic liquid containing bisulfate, fluorine compound, polyol, and water as raw materials. The various components in the copper-titanium etching solution work together to make the etching solution uniform, reduce local over-etching or residue, and is suitable for the precision etching of Cu / Ti stacks. The copper-titanium etching solution provided by the present invention has the advantages of high stability and long life, is environmentally friendly, has strong process adaptability, is suitable for the processing of precision electronic devices, and effectively reduces production costs.

Description

Technical Field

[0001] The invention belongs to the technical field of etching solutions, and in particular relates to a highly stable and long-life copper-titanium etching solution and a preparation method and application thereof. Background Art

[0002] In the manufacture of integrated circuits, PCBs, and display panels, persulfate-based copper-titanium etchants achieve selective etching by oxidizing copper and titanium into soluble metal ions, leveraging the strong oxidizing properties of persulfate. However, during the etching process, persulfate ions are continuously consumed, leading to a large accumulation of copper and titanium ions generated by the reaction. Copper ions catalyze the decomposition of persulfate, accelerating the ineffective consumption of persulfate ions and causing a rapid decline in the oxidizing capacity of the etchant. This, in turn, leads to problems such as fluctuating etching rates, localized overetching, or incomplete etching, severely impacting product yield and consistency. Furthermore, pH fluctuations during recycling further reduce the oxidizing activity and stability of the persulfate.

[0003] Patent KR1020200068131A discloses an etchant composition and a method for manufacturing metal patterns and array substrates using the etchant composition. The etchant composition comprises a persulfate, a tetrazocyclic compound, a dichloro compound, a fluorine compound, and water, wherein the weight ratio of the tetrazocyclic compound to the dichloro compound is approximately 1:0.5 to approximately 1:4. The etchant composition can etch titanium / copper multilayers and can be used to manufacture metal patterns and array substrates having excellent etching pattern properties. However, the formulation does not effectively solve the stability problem caused by the attenuation of the oxidizing ability of the etching solution.

[0004] Patent CN120006294A discloses a copper-titanium etching solution and a preparation method thereof. The copper-titanium etching solution comprises potassium permonosulfate complex, sodium percarbonate, benzotriazole-2,3-dicarboxylic acid, 5-aminotetrazole, tetrasodium ethylenediaminetetraacetic acid, hydroxyethylidene diphosphonic acid, cocamidopropyl betaine, benzotriazole, 2-mercaptobenzothiazole, poly-N-isopropylacrylamide, potassium perchlorate, and the balance ultrapure water. The etching solution primarily achieves precise control of the copper-titanium etching rate and effectively suppresses undercutting and titanium residue. However, the etching solution has a short service life and storage period, and the maximum copper ion load is limited to 8300 ppm, making it difficult to meet the needs of long-term, large-scale production.

[0005] Patent CN118957588A discloses a metal film wiring etching solution, its preparation method, and its application. The etching solution comprises an oxidizing cerium salt, an organic sulfonic acid, a peroxide compound, a stabilizer, a functionalized ionic liquid, an amino acid oligomer, a pyrosulfate salt, an alcohol ether solvent, a Gemini surfactant, and the balance is water. This etching solution is specifically designed for etching wiring of various specifications and chromium composite membrane processes. Its etching effectiveness relies on the oxidizing cerium salt. The etching solution exhibits no precipitation after 72 hours, but its etching performance is unknown.

[0006] Based on the above statements, the existing persulfate system copper-titanium etching solution technology still has the defects of poor etching stability and short life, and urgently needs to be improved. Summary of the Invention

[0007] In order to solve the above technical problems, one of the purposes of the present invention is to provide a copper-titanium etching solution with high stability and long life.

[0008] The technical solution adopted in the present invention is:

[0009] A highly stable and long-life copper-titanium etching solution comprises, by mass percentage, 5-15% persulfate, 3-15% organic acid, 0.5-3% sulfonated cyclodextrin, 0.1-4% acidic ionic liquid containing hydrogen sulfate, 0.05-1% fluorine compound, 0.01-2% polyol, and the balance being water.

[0010] Preferably, the persulfate is selected from at least one of potassium persulfate, sodium persulfate, and ammonium persulfate. The amount of the persulfate is not limited to 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 12%, 13%, 14%, or 15%.

[0011] Preferably, the sulfonated cyclodextrin is sulfobutyl-β-cyclodextrin. The amount of the sulfonated cyclodextrin is not limited to 0.5%, 0.7%, 0.9%, 1.0%, 1.5%, 1.9%, 2.0%, 2.4%, 2.7%, or 3.0%.

[0012] Preferably, the bisulfate-containing acidic ionic liquid is selected from at least one of an imidazole bisulfate ionic liquid, a pyridine bisulfate ionic liquid, and a pyrrolidone bisulfate ionic liquid. The amount of the bisulfate-containing acidic ionic liquid is not limited to 0.1%, 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, or 4.0%.

[0013] Preferably, the imidazole bisulfate ionic liquid is selected from at least one of 1-butyl-3-methylimidazolium bisulfate, 1-carboxymethyl-3-methylimidazolium bisulfate, and 1-hydroxyethyl-3-methylimidazolium bisulfate;

[0014] The pyridine bisulfate ionic liquid is selected from at least one of N-ethylpyridine bisulfate, N-butylpyridine bisulfate, and N-hexylpyridine bisulfate;

[0015] The pyrrolidone bisulfate ionic liquid is selected from at least one of 2-pyrrolidone bisulfate, 1-methyl-2-pyrrolidone bisulfate, and 1-(3-sulfonic acid)-propyl-2-pyrrolidone bisulfate.

[0016] Preferably, the fluorine compound is selected from at least one of hydrofluoric acid, ammonium fluoride, potassium fluoride, sodium fluoride, ammonium bifluoride, potassium bifluoride, and sodium bifluoride. The amount of the fluorine compound is not limited to 0.05%, 0.08%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.7%, 0.9%, or 1.0%.

[0017] Preferably, the organic acid is selected from at least one of citric acid, malic acid, acetic acid, propionic acid, oxalic acid, lactic acid, tartaric acid, and succinic acid. The amount of the organic acid is not limited to 3%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 12%, 13%, 14%, and 15%.

[0018] Preferably, the polyol is selected from at least one of diethylene glycol, ethylene glycol, glycerol, 1,2-propylene glycol, 1,4-butylene glycol, pentaerythritol, mannitol, and xylitol. The amount of the polyol is not limited to 0.01%, 0.05%, 0.1%, 0.2%, 0.4%, 0.7%, 1.0%, 1.3%, 1.6%, 1.9%, or 2.0%.

[0019] In the above formula, persulfate acts as a strong oxidant in the etching solution, providing the oxidizing ability required for etching, and converting copper and titanium metals into soluble ions through oxidation reactions, thereby achieving selective etching.

[0020] Acidic ionic liquids containing bisulfate not only provide hydrogen ions and bisulfate ions to maintain an acidic environment and promote the dissolution of metal ions, but also imidazole, pyridine, and pyrrolidone cations can be adsorbed on the surface of the metal film layer to inhibit over-etching side reactions; at the same time, cations can also form stable ion pairs with persulfate through electrostatic and conjugated effects, slowing the decomposition rate of persulfate and extending the life of the etching solution; compared with traditional inorganic bisulfate, the etching is more uniform.

[0021] Sulfonated cyclodextrin, on the one hand, accelerates the etching rate and regulates the pH value of the etching solution, promoting uniform etching and reducing localized overetching or incomplete etching. On the other hand, the cyclodextrin cavity structure encapsulates copper ions and sulfonate complexes the copper ions, reducing the copper ion's catalytic effect on the decomposition of persulfate, thereby extending the life of the etching solution. Furthermore, sulfonated cyclodextrin, when combined with an acidic ionic liquid containing bisulfate, effectively inhibits the ineffective decomposition of persulfate ions and slows the decay of oxidative capacity, thereby achieving a highly stable and long-lasting copper-titanium etching solution.

[0022] During the etching process, titanium easily forms a dense titanium oxide passivation layer, which hinders further reaction. Fluoride ions provided by fluorine compounds form soluble complexes with titanium ions, destroying the passivation layer and significantly increasing the titanium etching rate. Fluoride ions work synergistically with persulfate to accelerate the oxidation and dissolution of titanium, avoiding titanium residue, better controlling the copper / titanium etching rate ratio, and reducing undercutting or overetching.

[0023] The carboxylate radical of the organic acid forms a stable complex with copper ions and titanium ions, reducing the adverse effects of metal ion accumulation on the system, while improving the solubility of the etching product and reducing precipitation.

[0024] Polyols can prevent the precipitation of etching by-products and maintain the uniformity of the etching solution; reduce the risk of equipment pipeline blockage and improve process stability.

[0025] A second object of the present invention is to provide a method for preparing a highly stable and long-life copper-titanium etching solution as described above, wherein a persulfate, an organic acid, a sulfonated cyclodextrin, an acidic ionic liquid containing bisulfate, a fluorine compound, a polyol and water are mixed according to the required ratio of the copper-titanium etching solution to obtain the copper-titanium etching solution.

[0026] A third object of the present invention is to provide a use of the above-mentioned highly stable and long-life copper-titanium etching solution in etching copper-titanium laminated materials.

[0027] The beneficial effects of the present invention are:

[0028] A new etching solution formula is provided, using persulfate, organic acid, sulfonated cyclodextrin, acidic ionic liquid containing bisulfate, fluorine compound, polyol, and water as raw materials. By regulating the dosage ratio, a highly stable and long-life copper-titanium etching solution is obtained. The sulfonated cyclodextrin can effectively regulate the etching rate of copper and titanium, ensuring uniform etching. The acidic ionic liquid containing bisulfate can ensure that the etching solution maintains excellent etching performance for a long time and effectively prevents the occurrence of localized over-etching. Functionalized cations are selectively adsorbed on the copper and titanium surfaces, reducing the long tailing phenomenon caused by incomplete titanium etching. The sulfonated cyclodextrin and acidic ionic liquid containing bisulfate work together to effectively inhibit the ineffective decomposition of persulfate ions and significantly enhance the stability of the etching solution. They also work in conjunction with the main oxidant persulfate to regulate the etching rate uniformity, inhibit lateral corrosion, and reduce tailing.

[0029] Experiments show that after dissolving 8000ppm of copper powder and leaving it for 12 hours, the copper-titanium etching solution still has excellent etching performance and high stability. Moreover, even when the copper addition concentration is as high as 12000ppm, the copper-titanium etching solution can still accurately control the etching cone angle and CD bias of the Cu / Ti stack and reduce the tail size.

[0030] The various components in the copper-titanium etching solution work together to make the etching solution etch evenly, reducing local over-etching or residue. It is suitable for precision etching of Cu / Ti stacks. It has the advantages of high stability and long life, and is environmentally friendly and has strong process adaptability. It is suitable for precision electronic device processing and effectively reduces production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a SEM image of the etching effect of the highly stable and long-life copper-titanium etching solution of Example 1 of the present invention. In the figure: 1 is the cone angle, 2 is the CD bais, and 3 is the tail;

[0032] Figure 2 This is a SEM image of the etching effect of the highly stable and long-life copper-titanium etching solution of Example 2 of the present invention. In the figure: 1 is CDbais, 2 is tail, and 3 is cone angle;

[0033] Figure 3 This is a SEM image of the etching effect of the highly stable and long-life copper-titanium etching solution of Example 3 of the present invention. In the figure: 1 is CDbais, 2 is tail, and 3 is cone angle;

[0034] Figure 4 This is a SEM image of the etching effect of the highly stable and long-life copper-titanium etching solution of Comparative Example 1 of the present invention. In the figure: 1 is the tail, 2 is the CD bais, and 3 is the cone angle;

[0035] Figure 5 This is a SEM image of the etching effect of the highly stable and long-life copper-titanium etching solution of comparative example 2 of the present invention. In the figure: 1 is CDbais, 2 is tail, and 3 is cone angle;

[0036] Figure 6 This is a SEM image of the etching effect of the highly stable and long-life copper-titanium etching solution of comparative example 3 of the present invention. In the figure: 1 is the cone angle, 2 is the CD bais, and 3 is the tail;

[0037] Figure 7 This is a SEM image of the etching effect of the highly stable and long-life copper-titanium etching solution of comparative example 4 of the present invention. In the figure: 1 is the tail, 2 is the CD bais, and 3 is the cone angle;

[0038] Figure 8This is an SEM image of the etching effect of the highly stable and long-life copper-titanium etching solution of comparative example 5 of the present invention. On the figure: 1 is the cone angle, 2 is the CD bais, and 3 is the tail. DETAILED DESCRIPTION

[0039] For ease of understanding, the technical solution of the present invention is described in more detail below with reference to the embodiments. Unless otherwise specified, the terms used herein have the meanings commonly understood by those skilled in the art.

[0040] Example 1

[0041] A highly stable and long-life copper-titanium etching solution comprises the following components, calculated by mass percentage: 10% persulfate, 8% organic acid, 1.5% sulfonated cyclodextrin, 2% acidic ionic liquid containing hydrogen sulfate, 0.5% fluorine compound, 1.25% polyol, and the balance being water.

[0042] Among them, the persulfate is ammonium persulfate; the organic acid is citric acid; the sulfonated cyclodextrin is sulfobutyl-β-cyclodextrin; the acidic ionic liquid containing hydrogen sulfate is 1-butyl-3-methylimidazolium hydrogen sulfate; the fluorine compound is hydrofluoric acid; and the polyol is diethylene glycol.

[0043] The preparation method is as follows: persulfate, organic acid, sulfonated cyclodextrin, acidic ionic liquid containing hydrogen sulfate, fluorine compound, polyol and water are uniformly mixed according to the above formula to obtain the product.

[0044] Example 2

[0045] A highly stable and long-life copper-titanium etching solution comprises the following components, calculated by mass percentage: 5% persulfate, 15% organic acid, 3% sulfonated cyclodextrin, 4% acidic ionic liquid containing hydrogen sulfate, 1% fluorine compound, 2% polyol, and the balance being water.

[0046] The persulfate is potassium persulfate; the organic acid is malic acid; the sulfonated cyclodextrin is sulfobutyl-β-cyclodextrin; the acidic ionic liquid containing bisulfate is N-ethylpyridinium bisulfate; the fluorine compound is ammonium fluoride; and the polyol is glycerol.

[0047] The preparation method is as follows: persulfate, organic acid, sulfonated cyclodextrin, acidic ionic liquid containing hydrogen sulfate, fluorine compound, polyol and water are uniformly mixed according to the above formula to obtain the product.

[0048] Example 3

[0049] A highly stable and long-life copper-titanium etching solution comprises the following components, calculated by mass percentage: 15% persulfate, 3% organic acid, 0.5% sulfonated cyclodextrin, 0.1% acidic ionic liquid containing hydrogen sulfate, 0.05% fluorine compound, 0.01% polyol, and the balance being water.

[0050] Among them, the persulfate is sodium persulfate; the organic acid is tartaric acid; the sulfonated cyclodextrin is sulfobutyl-β-cyclodextrin; the acidic ionic liquid containing hydrogen sulfate is 1-hydroxyethyl-3-methylimidazolium hydrogen sulfate; the fluorine compound is potassium fluoride; and the polyol is mannitol.

[0051] The preparation method is as follows: persulfate, organic acid, sulfonated cyclodextrin, acidic ionic liquid containing hydrogen sulfate, fluorine compound, polyol and water are uniformly mixed according to the above formula to obtain the product.

[0052] Comparative Example 1

[0053] The preparation method of Comparative Example 1 is the same as that of Example 1, except that an equal amount of sulfosalicylic acid is used instead of sulfonated cyclodextrin.

[0054] Comparative Example 2

[0055] The preparation method of Comparative Example 2 is the same as that of Example 1, except that an equal amount of β-cyclodextrin is used instead of sulfonated cyclodextrin.

[0056] Comparative Example 3

[0057] The preparation method of Comparative Example 3 is the same as that of Example 1, except that an equal mass of sodium bisulfate is used to replace the acidic ionic liquid containing bisulfate.

[0058] Comparative Example 4

[0059] The preparation method of Comparative Example 4 is the same as that of Example 1, except that the acidic ionic liquid containing bisulfate is not added.

[0060] Comparative Example 5

[0061] The preparation method of Comparative Example 5 is the same as that of Example 1, except that sulfonated cyclodextrin is not added.

[0062] Performance Testing

[0063] 1. Etching effect

[0064] The etching effect of the copper-titanium etching solution prepared in Examples 1-3 and Comparative Examples 1-5 was tested. At 26°C, an etching machine was used to etch a copper-titanium substrate (Cu / Ti=7500 / 100Å). The total etching time was 2.0 times the EPD. EPD is the time required for the copper-titanium substrate to become transparent during the etching process, which is the etching endpoint time. By controlling the total etching time to 2.0 times the EPD, the formation of the etching cone angle can be ensured to meet the target requirements. After the etching is completed, the copper-titanium substrate is taken out and after cleaning and drying, a scanning electron microscope (SEM) is used to observe the cone angle, CD bias (critical dimension deviation, in this test, the side etching amount of the bottom of the Cu metal film layer is used to characterize it), and tail (tailing, in this test, the titanium tailing is measured) to evaluate the etching effect. The results are shown in Table 1 and Figure 1-8 shown.

[0065] Table 1 Etching effect of copper-titanium substrate

[0066] ;

[0067] Figures 1-8 The etching effects of the copper-titanium etching solutions prepared in Examples 1-3 and Comparative Examples 1-5 respectively.

[0068] From Table 1 and Figure 1-8 It can be seen that the etching effects of Examples 1-3 are better than those of Comparative Examples 1-5. Among them, from Example 1 compared with Comparative Examples 1 and 2, it can be seen that the etching solution formula of the present invention uses sulfonated cyclodextrin, which can better adjust the etching rate of copper and titanium than sulfosalicylic acid or β-cyclodextrin, and ensure uniform etching; from Example 1 compared with Comparative Example 3, it can be seen that the etching solution formula of the present invention uses an acidic ionic liquid containing bisulfate, which can effectively prevent the occurrence of local over-etching compared with sodium bisulfate, and the imidazole cations are selectively adsorbed on the copper and titanium surfaces, reducing the long tailing phenomenon caused by incomplete titanium etching. From Example 1 compared with Comparative Examples 4 and 5, it can be seen that the etching solution formula of the present invention uses sulfonated cyclodextrin and an acidic ionic liquid containing bisulfate, and the two work together to cooperate with the main oxidant persulfate to regulate the uniformity of the etching rate, inhibit lateral corrosion, and reduce the tailing phenomenon.

[0069] 2. Stability assessment

[0070] Copper powder was added to the etching solutions prepared in Examples 1-3 and Comparative Examples 1-5 for dissolution. When the copper ion concentration in the etching solution reached 8000 ppm, the etching solution was stored at room temperature in the dark. The etching ability of the etching solution on the substrate (Cu / Ti = 7500 / 100 Å) was examined at the initial stage, 4 h, 8 h, 12 h, and 14 h later. The CD bias and tail were observed using a scanning electron microscope (SEM) to evaluate the etching effect. The results were recorded in Table 2 according to the following evaluation criteria:

[0071] 〇: 0.4μm < CD bias ≤ 0.6μm; Δ: 0.6μm < CD bias < 1.0μm; ×: CD bias ≤ 0.4μm or ≥ 1.0μm;

[0072] 〇: tail ≤ 0.20μm; Δ: 0.20μm < tail < 0.30μm; ×: tail ≥ 0.30μm.

[0073] Table 2 Etching effect after dissolving copper powder

[0074] ;

[0075] "-" indicates that when the evaluation of CD bias or tail is "×", no subsequent tests will be carried out, indicating that the stability of the etching solution cannot meet the requirements.

[0076] As can be seen from Table 2, the etching solution provided by the present invention has good etching stability. From Example 1 and Comparative Examples 1 and 2, it can be seen that sulfonated cyclodextrin is more helpful in improving the stability of the etching solution than sulfosalicylic acid and β-cyclodextrin; from Example 1 and Comparative Example 3, it can be seen that the acidic ionic liquid containing bisulfate can ensure that the etching solution maintains excellent etching performance for a long time compared with sodium bisulfate; from Example 1 and Comparative Examples 4 and 5, it can be seen that the sulfonated cyclodextrin and the acidic ionic liquid containing bisulfate in the present invention act together to effectively inhibit the ineffective decomposition of persulfate ions and significantly enhance the stability of the etching solution.

[0077] 3. Life assessment

[0078] The copper layer of the copper-titanium substrate is relatively thick, and a large amount of copper ions will be generated during the etching process. These accumulated copper ions will react with the key components in the etching solution (such as persulfate as the main oxidant), consume its effective concentration or reduce its redox potential, thereby weakening the etching ability; in addition, the accumulation of copper ions will also interfere with the functions or synergistic effects of other components, resulting in the deterioration of the etching performance, and ultimately seriously affecting the efficiency and service life of the etching solution. Therefore, taking copper ions as the main influencing factor, the copper dissolution amount is used in this embodiment to characterize the life of the copper etching solution.

[0079] Copper powder was added to the etching solutions prepared in Examples 1-3 and Comparative Examples 1-5 for dissolution. When the copper ion concentration in the etching solution reached 4000 ppm, 6000 ppm, 8000 ppm, 10000 ppm, 12000 ppm, and 14000 ppm, they were respectively poured into an etching machine. At 26 °C, a copper-titanium substrate (Cu / Ti = 7500 / 100 Å) was etched. The total etching time was 2.0 times the EPD. The EPD is the total time when it is observed that all the copper and titanium are completely etched during the etching process. By controlling the total etching time to be 2.0 times the EPD, the formation of the etching cone angle can be ensured. The etching effect was observed using a scanning electron microscope (SEM) to evaluate the CD bias and the tail. The results were recorded in Table 3 according to the following evaluation criteria:

[0080] 〇: 0.4 μm < CD bais ≤ 0.6 μm; Δ: 0.6 μm < CD bais < 1.0 μm; ×: CD bais ≤ 0.4 μm or ≥ 1.0 μm;

[0081] 〇: tail ≤ 0.20 μm; Δ: 0.20 μm < tail < 0.30 μm; ×: tail ≥ 0.30 μm.

[0082] Table 3 Etching effects after dissolving copper powder at different concentrations

[0083] ;

[0084] "-" indicates that when the evaluation of CD bais or tail is "×", no further tests are carried out, indicating that the copper ion content in the etching solution has exceeded its service life.

[0085] As can be seen from Table 3, after the copper ion concentration in the etching solutions provided in Examples 1-3 gradually increased from 4000 ppm to 12000 ppm, the copper-titanium substrate could be etched, and the range of the CD bais value was more accurate and the tail value was smaller. This shows that the etching performance of the etching solution provided by the present invention is more stable during the entire etching process and will not show large fluctuations due to the increase in the copper ion concentration. The formula of the present invention can extend the service life of the etching solution under the accumulation of copper ions; while in Comparative Examples 1-5, the situation where the etching process could not proceed due to the gradual increase in the copper ion concentration in the etching solution occurred, that is, the etching solutions provided by Comparative Examples 1-5 have a shorter service life under the accumulation of copper ions.

[0086] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention should be included within the protection scope of the present invention.

Claims

1. A highly stable and long-life copper-titanium etching solution, characterized in that: Calculated by mass percentage, the composition includes: 5-15% persulfate, 3-15% organic acid, 0.5-3% sulfonated cyclodextrin, 0.1-4% acidic ionic liquid containing hydrogen sulfate, 0.05-1% fluorine compound, 0.01-2% polyol, and the balance is water.

2. A highly stable and long-life copper-titanium etching solution as claimed in claim 1, characterized in that: The persulfate is selected from at least one of potassium persulfate, sodium persulfate, and ammonium persulfate.

3. A highly stable and long-life copper-titanium etching solution as claimed in claim 1, characterized in that: The sulfonated cyclodextrin is sulfobutyl-β-cyclodextrin.

4. A highly stable and long-life copper-titanium etching solution as claimed in claim 1, characterized in that: The acidic ionic liquid containing bisulfate is selected from at least one of imidazole bisulfate ionic liquids, pyridine bisulfate ionic liquids, and pyrrolidone bisulfate ionic liquids.

5. A highly stable and long-life copper-titanium etching solution as claimed in claim 4, characterized in that: The imidazole hydrogen sulfate ionic liquid is selected from at least one of 1-butyl-3-methylimidazole hydrogen sulfate, 1-carboxymethyl-3-methylimidazole hydrogen sulfate, and 1-hydroxyethyl-3-methylimidazole hydrogen sulfate; The pyridine bisulfate ionic liquid is selected from at least one of N-ethylpyridine bisulfate, N-butylpyridine bisulfate, and N-hexylpyridine bisulfate; The pyrrolidone bisulfate ionic liquid is selected from at least one of 2-pyrrolidone bisulfate, 1-methyl-2-pyrrolidone bisulfate, and 1-(3-sulfonic acid)-propyl-2-pyrrolidone bisulfate.

6. A highly stable and long-life copper-titanium etching solution as claimed in claim 1, characterized in that: The fluorine compound is selected from at least one of hydrofluoric acid, ammonium fluoride, potassium fluoride, sodium fluoride, ammonium bifluoride, potassium bifluoride, and sodium bifluoride.

7. A highly stable and long-life copper-titanium etching solution as claimed in claim 1, characterized in that: The organic acid is selected from at least one of citric acid, malic acid, acetic acid, propionic acid, oxalic acid, lactic acid, tartaric acid, and succinic acid.

8. A highly stable and long-life copper-titanium etching solution as claimed in claim 1, characterized in that: The polyol is selected from at least one of diethylene glycol, ethylene glycol, glycerol, 1,2-propylene glycol, 1,4-butanediol, pentaerythritol, mannitol, and xylitol.

9. A method for preparing a highly stable and long-life copper-titanium etching solution according to any one of claims 1 to 8, characterized in that: According to the required ratio of the copper-titanium etching solution, persulfate, organic acid, sulfonated cyclodextrin, acidic ionic liquid containing hydrogen sulfate, fluorine compound, polyol and water are mixed to obtain the copper-titanium etching solution.

10. Use of the highly stable and long-life copper-titanium etching solution according to any one of claims 1 to 8 in etching copper-titanium laminated materials.

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