Etching solution and preparation method and etching method thereof

Abstract

The invention relates to the technical field of metal etching solutions, in particular to an etching solution as well as a preparation method and an etching method thereof. The etching liquid comprises the following components in percentage by mass: 5 to 10 weight percent of hydrogen peroxide, 4 to 6 weight percent of nitric acid, 0.1 to 5 weight percent of hydrogen peroxide stabilizer, 0.1 to 5 weight percent of metal ion chelating agent, 0.01 to 5 weight percent of metal corrosion inhibitor, 0.3 to 0.5 weight percent of chlorinated diphenyl iodonium and the balance of water. In the etching solution, the content of hydrogen peroxide is low, and fluorine ions are not contained; the etching liquid has the advantages of being high in safety, good in stability, excellent in etching performance, capable of meeting the high-precision machining requirement and the like. When the etching solution is used for etching an etched sheet containing a copper-titanium metal film, uniform etching can be realized, the CD bias variation is less than 0.1 mu m, the etching CD and the slope angle are basically unchanged, and no surface metal residue and no titanium residue phenomenon exist.

Description

Technical Field

[0001] The invention relates to the technical field of metal etching liquid, in particular to an etching liquid and a preparation method and an etching method thereof. Background Art

[0002] At present, in the production process of high-generation LCD panels, copper is used for gates and metal wiring. Compared with the previous aluminum, it has the advantages of low resistance and no environmental problems. However, the adhesion of copper to the glass substrate and the insulating film is low, and titanium is usually used as the lower thin film metal. Therefore, the copper-titanium metal film needs to be etched. In the etching process of the copper-titanium metal film, titanium is more difficult to etch than copper, and the etching rate of titanium is much lower than that of copper.

[0003] Existing copper-titanium metal film etching solutions usually add fluoride or greatly increase the hydrogen peroxide content to increase the etching speed of titanium metal and remove the titanium metal residues produced during etching. However, adding fluoride has the following disadvantages: first, the fluoride ionization produces fluoride ions, which pollutes the environment and has high treatment costs for etching waste liquid; second, fluoride ions are highly toxic; third, fluoride ions are highly corrosive and will etch the glass substrate, easily causing defects on the glass substrate and affecting display performance.

[0004] In view of this, this invention is proposed. Summary of the invention

[0005] The first purpose of the present invention is to provide an etching solution with low hydrogen peroxide content, no fluoride ions, high safety, good stability, excellent etching performance, and the ability to meet high-precision processing requirements; for etching of etched wafers containing copper-titanium metal films, there is no titanium residue.

[0006] The second object of the present invention is to provide a method for preparing an etching solution, which has simple steps and is suitable for large-scale production.

[0007] The third object of the present invention is to provide an etching method, using the above-mentioned etching solution to etch an etching sheet containing a copper-titanium metal film, wherein the CD bias change of the etching solution during the etching process is less than 0.1 μm; during the service life of the etching solution, the etching CD and slope angle remain basically unchanged, and there is no metal residue on the surface and no titanium residue.

[0008] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0009] In a first aspect, the present invention provides an etching solution, comprising the following components in percentage by mass:

[0010] 5wt%-10wt% of hydrogen peroxide, 4-6wt% of nitric acid, 0.1wt%-5wt% of hydrogen peroxide stabilizer, 0.1wt%-5wt% of metal ion chelating agent, 0.01wt%-5wt% of metal corrosion inhibitor, 0.3wt%-0.5wt% of diphenyliodonium chloride, and the balance is water.

[0011] The etching solution of the present invention adds hydrogen peroxide, is supplemented with a metal corrosion inhibitor and nitric acid, and simultaneously adds a hydrogen peroxide stabilizer, a metal ion chelating agent and diphenyl iodonium chloride, so that the etching solution has the advantages of high safety, good stability, no pollution to the environment, excellent etching performance, and the ability to meet high-precision processing requirements, and no titanium residue phenomenon occurs during the etching process of an etching sheet containing a copper-titanium metal film; wherein, the addition of a small amount of hydrogen peroxide can not only perform etching well and ensure uniform etching, but also ensure the safety and stability of the etching solution; the addition of nitric acid can increase the etching rate and ensure effective etching; the hydrogen peroxide stabilizer can improve the stability of hydrogen peroxide; the metal ion chelating agent can reduce the free metal ion content in the etching solution, reduce the influence on hydrogen peroxide, and make the etching solution safer and more stable; the metal corrosion inhibitor can effectively slow down the etching rate of metal copper; the addition of diphenyl iodonium chloride can achieve selective control of the reaction process and reduce titanium residue.

[0012] In a second aspect, the present invention further provides a method for preparing the etching solution as described above, comprising the following steps:

[0013] The components are mixed evenly to obtain the etching solution.

[0014] The invention can obtain the etching solution by uniformly mixing the components of the etching solution, has simple steps and is suitable for large-scale production.

[0015] In a third aspect, the present invention also provides an etching method, which uses the etching solution as described above to etch an etching wafer; the etching wafer includes a substrate and a metal film arranged on the surface of the substrate, and the metal film includes a copper metal film and a titanium metal film arranged on the surface of the copper metal film.

[0016] The etching solution of the present invention is used in the etching process of an etching wafer containing a copper-titanium metal film, and has good safety and stability, low operating risk, no pollution to the environment, and excellent etching performance; the etching solution can maintain pH stability during the etching process, and avoid the phenomenon of uneven etching caused by pH changes; the CD bias change of the etching solution during the etching process is less than 0.1 μm; within the entire service life of the etching solution, the etching CD and the slope angle remain basically unchanged, there is no metal residue on the surface, and no titanium residue phenomenon, and the high-precision processing requirements can be met. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 This is a cross-sectional SEM image of the copper-titanium metal film after being etched using the initial state etching solution of Example 1 of the present invention.

[0019] Figure 2 This is a cross-sectional SEM image of the copper-titanium metal film after being etched using the end-of-life etching solution of Example 1 of the present invention.

[0020] Figure 3 This is a surface SEM image of the copper-titanium metal film after being etched using the initial state etching solution of Example 1 of the present invention. DETAILED DESCRIPTION

[0021] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but it will be understood by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0022] An etching solution, a preparation method thereof, and an etching method according to an embodiment of the present invention are described in detail below.

[0023] In some embodiments of the present invention, an etching solution is provided, which comprises the following components in terms of mass percentage:

[0024] 5wt%-10wt% of hydrogen peroxide, 4-6wt% of nitric acid, 0.1wt%-5wt% of hydrogen peroxide stabilizer, 0.1wt%-5wt% of metal ion chelating agent, 0.01wt%-5wt% of metal corrosion inhibitor, 0.3wt%-0.5wt% of diphenyliodonium chloride, and the balance is deionized water.

[0025] The etching solution of the present invention adds a small amount of hydrogen peroxide, is supplemented with a metal corrosion inhibitor and nitric acid, and simultaneously adds a hydrogen peroxide stabilizer, a metal ion chelating agent and diphenyliodonium chloride. The components cooperate with each other, so that the etching solution has the advantages of high safety, good stability, no pollution to the environment, excellent etching performance, and the ability to meet high-precision processing requirements.

[0026] The etching solution of the present invention is used for etching, which can maintain pH stability during the etching process, ensure etching uniformity, and avoid the phenomenon of uneven etching caused by pH change; the CD bias change of the etching solution during the etching process is less than 0.1 μm; and the etching CD and slope angle remain substantially unchanged throughout the service life of the etching solution.

[0027] The etching liquid of the invention is a copper-titanium etching liquid, which is suitable for etching copper-titanium metal films. During the etching process of the copper-titanium metal films, no metal residues on the surface and no titanium residues occur.

[0028] The etching solution of the invention does not contain fluorine ions, has no pollution to the environment, is simple to treat waste liquid, and has low operating risk for personnel.

[0029] The etching solution of the present invention has a low hydrogen peroxide content and is added with a hydrogen peroxide stabilizer, thereby improving the safety and stability of the etching solution and avoiding explosion caused by violent decomposition of hydrogen peroxide, thereby preventing casualties and property losses.

[0030] For example, in different embodiments, the mass percentages of the components in the etching solution may be as follows:

[0031] The mass percentage of hydrogen peroxide can be 5wt%, 5.2wt%, 5.4wt%, 5.6wt%, 5.8wt%, 6wt%, 6.2wt%, 6.4wt%, 6.6wt%, 6.8wt%, 7wt%, 7.2wt%, 7.4wt%, 7.6wt%, 7.8wt%, 8wt%, 8.2wt%, 8.4wt%, 8.6wt%, 8.8wt%, 9wt%, 9.2wt%, 9.4wt%, 9.6wt%, 9.8wt%, 10wt% or a range consisting of any two of them;

[0032] The mass percentage of nitric acid can be 4wt%, 4.2wt%, 4.4wt%, 4.6wt%, 4.8wt%, 5wt%, 5.2%, 5.4wt%, 5.6wt%, 5.8wt%, 6wt% or a range consisting of any two thereof;

[0033] The mass percentage of the hydrogen peroxide stabilizer can be 0.1wt%, 0.5wt%, 1wt%, 1.2wt%, 1.4wt%, 1.6wt%, 1.8wt%, 2wt%, 2.2wt%, 2.4wt%, 2.6wt%, 2.8wt%, 3wt%, 3.2wt%, 3.4wt%, 3.6wt%, 3.8wt%, 4wt%, 4.2wt%, 4.4wt%, 4.6wt%, 4.8wt%, 5wt% or a range consisting of any two of them;

[0034] The mass percentage of the metal ion chelating agent can be 0.1wt%, 0.5wt%, 1wt%, 1.2wt%, 1.4wt%, 1.6wt%, 1.8wt%, 2wt%, 2.2wt%, 2.4wt%, 2.6wt%, 2.8wt%, 3wt%, 3.2wt%, 3.4wt%, 3.6wt%, 3.8wt%, 4wt%, 4.2wt%, 4.4wt%, 4.6wt%, 4.8wt%, 5wt% or a range consisting of any two of them;

[0035] The mass percentage of the metal corrosion inhibitor can be 0.01wt%, 0.1wt%, 0.5wt%, 1wt%, 1.2wt%, 1.4wt%, 1.6wt%, 1.8wt%, 2wt%, 2.2wt%, 2.4wt%, 2.6wt%, 2.8wt%, 3wt%, 3.2wt%, 3.4wt%, 3.6wt%, 3.8wt%, 4wt%, 4.2wt%, 4.4wt%, 4.6wt%, 4.8wt%, 5wt% or a range consisting of any two of them;

[0036] The mass percentage of diphenyliodonium chloride can be 0.3wt%, 0.32wt%, 0.34wt%, 0.36wt%, 0.38wt%, 0.4wt%, 0.42wt%, 0.44wt%, 0.46wt%, 0.48wt%, 0.5wt% or a range consisting of any two of them.

[0037] The etching solution of the invention has excellent etching performance by adding appropriate amounts of hydrogen peroxide, nitric acid, hydrogen peroxide stabilizer, metal ion chelating agent, metal corrosion inhibitor and diphenyliodonium chloride, and each component is scientifically matched.

[0038] The etching solution of the present invention has a low content of hydrogen peroxide. By adding 5wt% to 10wt% of hydrogen peroxide by mass, both the effective etching and the uniformity of the etching can be ensured, and the safety and stability of the etching solution can be ensured. Hydrogen peroxide is used as a main oxidant. If the content of hydrogen peroxide in the etching solution is too low, the etching reaction will be too slow during the entire etching process. If the content of hydrogen peroxide in the etching solution is too high, the etching reaction will be too fast during the entire etching process. If the content of hydrogen peroxide in the etching solution is too low or too high, the CD bias change of the etching solution during the etching process will be higher than 0.1μm.

[0039] In the etching solution of the present invention, nitric acid with a mass percentage of 4wt% to 5wt% is added, which is conducive to ensuring the effective etching; the content of nitric acid affects the etching rate of the etching process; if the content of nitric acid in the etching solution is too low, the etching rate is significantly reduced, resulting in reduced production efficiency; if the content of nitric acid in the etching solution is too high, the etching rate is too fast, it is difficult to control the etching accuracy, and the processing difficulty is increased.

[0040] In the etching solution of the present invention, by adding a hydrogen peroxide stabilizer with a mass percentage of 1wt% to 2wt%, the etching performance of the etching solution is improved; when the content of the hydrogen peroxide stabilizer in the etching solution is low, the hydrogen peroxide cannot be effectively stabilized, and the etching effect is reduced; when the content of the hydrogen peroxide stabilizer in the etching solution is high, the pH value of the etching solution is increased, the cone angle becomes lower, and titanium residues are also generated during the etching process of the etching sheet containing the copper-titanium metal film.

[0041] In the etching solution of the present invention, by adding a metal ion chelating agent with a mass percentage of 2wt% to 5wt%, the safety and stability of the etching solution are improved; when the content of the metal ion chelating agent in the etching solution is low, the etching effect is reduced, the cone angle becomes low, the CD bias change of the etching solution during the etching process is higher than 0.1μm, and the etching process of the etching sheet containing the copper-titanium metal film is accompanied by titanium residue; when the content of the metal ion chelating agent in the etching solution is high, the etching effect is reduced, the cone angle becomes high, and the CD bias change of the etching solution during the etching process is higher than 0.1μm.

[0042] In the etching solution of the present invention, the addition of a metal corrosion inhibitor can adjust the etching rate. The addition of a metal corrosion inhibitor with a mass percentage of 0.01wt% to 5wt% can effectively slow down the etching rate of metal copper, so that the etching solution has a suitable etching rate for copper. The content of the metal corrosion inhibitor in the etching solution is relatively high, the cone angle becomes lower, the CD bias change of the etching solution during the etching process is higher than 0.1μm, and titanium residue exists during the etching process of an etching sheet containing a copper-titanium metal film.

[0043] In the etching solution of the present invention, by adding 0.3wt% to 0.5wt% of diphenyl iodonium chloride, titanium residue in the etching process of the etching sheet containing the copper-titanium metal film can be reduced; when the etching solution lacks diphenyl iodonium chloride or has a low content of diphenyl iodonium chloride, titanium residue will occur in the etching process of the etching sheet containing the copper-titanium metal film.

[0044] In some embodiments of the present invention, the etching solution comprises the following components in terms of mass percentage:

[0045] 7-8wt% of hydrogen peroxide, 4.8-5.2wt% of nitric acid, 1wt%-2wt% of hydrogen peroxide stabilizer, 2wt%-5wt% of metal ion chelating agent, 0.5wt%-1wt% of metal corrosion inhibitor, 0.3wt%-0.5wt% of diphenyliodonium chloride, and the balance is water.

[0046] In order to obtain an etching solution with better performance, the content of each component in the etching solution is optimized, which is beneficial to further improve the etching performance of the etching solution.

[0047] In some preferred embodiments of the present invention, the etching solution comprises the following components in terms of mass percentage:

[0048] 8wt% of hydrogen peroxide, 5wt% of nitric acid, 1wt%-2wt% of hydrogen peroxide stabilizer, 2wt%-5wt% of metal ion chelating agent, 0.5wt%-1wt% of metal corrosion inhibitor, 0.3wt%-0.5wt% of diphenyliodonium chloride, and the balance is water.

[0049] In some embodiments of the present invention, the pH of the etching solution is 0.5-1.5; typically but not limiting, for example, the pH of the etching solution can be 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5 or a range of any two thereof.

[0050] The pH of the etching solution of the present invention is within the range of 0.5 to 1.5, which is beneficial to improving the etching effect of the etching solution, has an excellent cone angle, and reduces titanium residue during the etching process of the etching wafer containing the copper-titanium metal film; when the pH of the etching solution is low, the etching effect is poor; when the pH of the etching solution is high, the cone angle during the etching process becomes lower, and titanium residue will also occur during the etching process of the etching wafer containing the copper-titanium metal film.

[0051] Hydrogen peroxide is an oxidant that can effectively oxidize copper and titanium metals by decomposing to produce hydrogen peroxide ions, and can be dissolved by nitric acid to achieve the purpose of etching; and the byproducts of the hydrogen peroxide reaction are only water and oxygen, which is completely pollution-free to the environment. Adding hydrogen peroxide to the etching solution of the present invention can not only ensure the progress of etching, etch copper and titanium metals well, ensure the uniformity of etching, but also ensure the safety and stability of the etching solution.

[0052] Nitric acid is a highly oxidizing and corrosive inorganic acid. It can oxidize many metals and non-metals and is highly corrosive to many materials. It is easily soluble in water to form a highly oxidizing aqueous solution. In order to ensure effective etching, the present invention adds nitric acid to the etching solution to increase the etching rate of copper and titanium metals; at the same time, it can promote the dissolution of copper and titanium oxidized by hydrogen peroxide.

[0053] In some embodiments of the present invention, the hydrogen peroxide stabilizer includes at least one of dipropylamine, n-butylamine, n-hexylamine, hexamethylenediamine, cyclohexylamine and diethylenetriamine.

[0054] The main function of the hydrogen peroxide stabilizer is to improve the stability of hydrogen peroxide, slow down the decomposition rate of hydrogen peroxide, and avoid the rapid decomposition of hydrogen peroxide when the metal ions increase, thereby reducing the effectiveness of the etching solution; the present invention adopts aliphatic organic amine hydrogen peroxide stabilizer, and aliphatic organic matter with a certain carbon chain length can effectively prevent the rapid decomposition of hydrogen peroxide.

[0055] In some embodiments of the present invention, the metal ion chelator comprises at least one of hydroxyethylidene diphosphonic acid, aminotrimethylene phosphonic acid, methylene diphosphonic acid, dipicolinic acid, aminotriacetic acid and glycolic acid.

[0056] The main function of metal ion chelators is to quickly form stable complexes with metal ions generated during the etching process through coordination chelation. Metal ion chelators can chelate copper ions and titanium ions generated during the etching process, reduce the content of free metal ions in the etching solution, reduce the impact of metal ions on hydrogen peroxide, and make the etching solution safer and more stable.

[0057] In some embodiments of the present invention, the metal corrosion inhibitor includes at least one of thiophene, thiazole, imidazole, pyrazole, monomethylimidazole, dimethylimidazole, trimethylimidazole, methylbenzotriazole, tetrazole and methyltetrazole.

[0058] A metal corrosion inhibitor is a substance that can prevent or slow down metal corrosion. When the metal corrosion inhibitor exists in an environment (medium) in an appropriate concentration and form, it can prevent or slow down material corrosion. In the etching solution of the present invention, a metal corrosion inhibitor of a nitrogen-containing heterocyclic organic compound is used. The nitrogen-containing heterocyclic organic compound can be adsorbed on the surface of metallic copper, effectively slowing down the etching rate of metallic copper.

[0059] The iodonium cation in diphenyliodonium chloride can achieve selectivity control in the reaction process. In the etching process of a wafer containing a copper-titanium metal film, it can suppress the etching rate of copper and increase the etching rate of titanium, thereby reducing the titanium residue in the same etching time.

[0060] In some embodiments of the invention, the water comprises deionized water.

[0061] In some embodiments of the present invention, the resistivity of the deionized water is greater than 15 MΩ·cm, and the total mass concentration of metal ions in the deionized water is less than 10 ppb.

[0062] In some embodiments of the present invention, a method for preparing the above etching solution is also provided, comprising the following steps:

[0063] The components are mixed to obtain an etching solution.

[0064] The invention can obtain the etching solution by uniformly mixing the components of the etching solution, has simple steps and is suitable for large-scale production.

[0065] In some embodiments of the present invention, an etching method is also provided, comprising the following steps:

[0066] The etching solution is used to etch the etching sheet; the etching sheet includes a substrate and a metal film arranged on the surface of the substrate, the metal film includes a copper metal film and a titanium metal film (copper-titanium metal film) arranged on the surface of the copper metal film, that is, the etching sheet includes an etching sheet containing a copper-titanium metal film.

[0067] The etching solution of the present invention is used in the etching process of an etching wafer containing a copper-titanium metal film, and has good safety and stability, low operating risk, no pollution to the environment, and excellent etching performance; the etching solution can maintain pH stability during the etching process, and avoid the phenomenon of uneven etching caused by pH changes; the CD bias change of the etching solution during the etching process is less than 0.1 μm; within the entire service life of the etching solution, the etching CD and the slope angle remain basically unchanged, there is no metal residue on the surface, and no titanium residue phenomenon, and the high-precision processing requirements can be met.

[0068] The metal film of the present invention may be other metal films, such as copper metal film, in addition to copper-titanium metal film; the etching solution of the present invention may also be used for etching wafers containing other metal films.

[0069] In some embodiments of the present invention, the ratio of the thickness of the copper metal film to the thickness of the titanium metal film is (5-15):1; typically but not limitatively, for example, the ratio of the thickness of the copper metal film to the thickness of the titanium metal film can be 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1 or a range of any two thereof.

[0070] In some embodiments of the present invention, the thickness of the copper metal film is The thickness of the titanium film is Preferably, the thickness of the copper metal film is The thickness of the titanium film is

[0071] In some embodiments of the present invention, the substrate includes, but is not limited to, glass.

[0072] In some embodiments of the present invention, the etching sheet includes glass, a titanium metal film and a copper metal film arranged in sequence.

[0073] In some embodiments of the present invention, the etching temperature is 25-35°C; typically but not limitatively, for example, the etching temperature can be 25°C, 26°C, 27°C, 28°C, 29°C, 30°C, 31°C, 32°C, 33°C, 34°C, 35°C or a range of any two thereof.

[0074] The etching solution of the present invention has an excellent etching effect at a temperature of 25 to 35°C.

[0075] In some embodiments of the present invention, the etching time is 100 to 200 s; typically but not limitatively, for example, the etching time can be 100 s, 110 s, 120 s, 130 s, 140 s, 150 s, 160 s, 170 s, 180 s, 190 s, 200 s or a range of any two thereof.

[0076] The etching solution of the present invention has excellent etching ability, high etching speed and short required etching time.

[0077] In some specific embodiments of the present invention, etching includes: spraying the etching wafer with an etching solution.

[0078] In some specific embodiments of the present invention, the etching method comprises the following steps:

[0079] At a temperature of 25 to 35° C., place the etched wafer in an etching machine and spray the etchant on the wafer for 100 to 200 seconds.

[0080] In some embodiments of the present invention, in the etching method, the etching cone angle is 40° to 55°.

[0081] In some embodiments of the present invention, in the etching method, the variation of CD bias during etching is less than 0.1 μm.

[0082] The etching solution of the present invention is used to etch an etched sheet containing a copper-titanium metal film, the etching cone angle is in the range of 40° to 55°, the etching CD bias variation is below 0.1 μm, and the etching solution has an excellent cone angle range and CD bias variation. In addition, there is no metal residue or titanium residue on the surface, and the substrate will not be corroded. The etching solution has an excellent etching effect and can meet high-precision processing requirements.

[0083] In some embodiments of the present invention, a method for preparing a TFT-LCD display panel is also provided, comprising etching using the above etching method.

[0084] TFT-LCD (Thin Film Transistor Liquid Crystal Display) display panel, that is, thin film transistor liquid crystal display, uses thin film transistor technology to improve image quality; the basic structure of TFT-LCD panel consists of two glass substrates with a layer of liquid crystal in the middle; the upper glass substrate is attached with a color filter, and the lower glass substrate is inlaid with thin film transistors, which include copper and titanium.

[0085] The above etching method is used in the process of TFT-LCD display panel, which can not only achieve excellent etching effect, without metal residue on the surface, meet the high-precision processing requirements, but also will not etch the glass substrate, which is beneficial to improve the display performance of the TFT-LCD display panel.

[0086] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0087] Examples 1 to 12

[0088] The method for preparing the etching solution provided in Examples 1 to 12 comprises the following steps:

[0089] The etching solution is obtained by uniformly mixing hydrogen peroxide, nitric acid, a hydrogen peroxide stabilizer, a metal ion chelating agent, a metal corrosion inhibitor, diphenyliodonium chloride and deionized water;

[0090] The resistivity of the deionized water is above 15 MΩ·cm, and the total mass concentration of metal ions in the deionized water is less than 10 ppb.

[0091] In the etching solutions of Examples 1 to 12, the contents of hydrogen peroxide, nitric acid, diphenyliodonium chloride and deionized water, and the types and contents of hydrogen peroxide stabilizer, metal ion chelating agent and metal corrosion inhibitor are shown in Table 1.

[0092] In Table 1, the contents are the mass percentages of hydrogen peroxide, nitric acid, hydrogen peroxide stabilizer, metal ion chelating agent, metal corrosion inhibitor or diphenyliodonium chloride in the etching solution.

[0093] Table 1

[0094]

[0095]

[0096] Comparative Examples 1 to 10

[0097] The preparation method of the etching solution provided in Comparative Examples 1 to 10 comprises the following steps:

[0098] The etching solution is obtained by uniformly mixing hydrogen peroxide, nitric acid, a hydrogen peroxide stabilizer, a metal ion chelating agent, a metal corrosion inhibitor, diphenyliodonium chloride and deionized water;

[0099] The resistivity of the deionized water is above 15 MΩ·cm, and the total mass concentration of metal ions in the deionized water is less than 10 ppb.

[0100] In the etching solutions of Comparative Examples 1 to 10, the contents of hydrogen peroxide, nitric acid, diphenyliodonium chloride and deionized water, and the types and contents of hydrogen peroxide stabilizer, metal ion chelating agent and metal corrosion inhibitor are shown in Table 2.

[0101] In Table 2, the contents are the mass percentages of hydrogen peroxide, nitric acid, hydrogen peroxide stabilizer, metal ion chelating agent, metal corrosion inhibitor or diphenyliodonium chloride in the etching solution.

[0102] Table 2

[0103]

[0104]

[0105] Test Example 1

[0106] The etching solution in the initial state of Example 1 was used to etch the etched sheet containing the copper-titanium metal film, and the cross section of the etched copper-titanium metal film was tested by scanning electron microscope. The results are as follows: Figure 1 shown.

[0107] The end-of-life etching solution of Example 1 was used to etch the copper-titanium metal film. The cross section of the copper-titanium metal film after etching was tested by scanning electron microscope. The results are as follows: Figure 2shown.

[0108] The etching solution in the initial state of Example 1 was used to etch the etched sheet containing the copper-titanium metal film, and the surface of the etched copper-titanium metal film was tested by scanning electron microscope. The results are as follows: Figure 3 shown.

[0109] The initial state etching solution refers to a newly prepared etching solution without copper ions; the end-of-life etching solution refers to an etching solution with a copper ion concentration of 5000 ppm.

[0110] The method for etching a sheet containing a copper-titanium metal film with an etching solution comprises the following steps:

[0111] At 30±0.5℃, the etched sheet was placed in a small etching machine for 130s, and then washed with pure water for 2min. After drying with nitrogen, a scanning electron microscope was used for observation and testing. The etched sheet may include glass, titanium metal film and copper metal film arranged in sequence, and the thickness ratio of the copper metal film to the titanium metal film is 10:1. For example, the thickness of the copper metal film may be The thickness of the titanium metal film can be

[0112] from Figure 1 and Figure 2 It can be seen that when the etching CD and slope angle are basically unchanged when the etching solution in the initial state and at the end of its life is used to etch the etched sheet containing the copper-titanium metal film, respectively; thus, it can be seen that the etching CD and slope angle are basically unchanged throughout the service life of the etching solution, and it has excellent etching performance.

[0113] from Figure 3 It can be seen that no copper or titanium residue remains on the etched wafer containing the copper-titanium metal film after etching.

[0114] Test Example 2

[0115] The etching solutions of Examples 1 to 12 and Comparative Examples 1 to 10 were used to etch the wafer containing the copper-titanium metal film, and the results are shown in Table 3.

[0116] The method of etching a sheet containing a copper-titanium metal film with an etching solution comprises the following steps:

[0117] At 30±0.5℃, the etched wafer was placed in a small etching machine for 130s, and then washed with pure water for 2min. After drying with nitrogen, the performance test was performed. The etched wafer may include glass, titanium metal film and copper metal film arranged in sequence, and the thickness ratio of the copper metal film to the titanium metal film is 10:1. For example, the thickness of the copper metal film may be The thickness of the titanium metal film can be

[0118] The test method of etching cone angle is: take pictures at SEM cross section magnification of 50K;

[0119] The evaluation criteria for etching cone angle are as follows:

[0120] Excellent: cone angle is 40°~55°; Good: cone angle is 35~40° or 55~60°; Poor: cone angle is <35° or >60°.

[0121] The test method for titanium residue is: taking pictures at a SEM surface magnification of 30K.

[0122] The CD bias variation test method is: take pictures at a SEM cross-section magnification of 40K;

[0123] The evaluation criteria for CD bias change are as follows:

[0124] Excellent: CD bias change <0.1μm; Good: CD bias change 0.1~0.2μm; Poor: CD bias change >0.2μm.

[0125] Table 3

[0126]

[0127]

[0128] It can be seen from Table 3 that, from the comparison between Examples 1-2 and Comparative Examples 1-2, it can be seen that when the hydrogen peroxide content in the etching solution is too low or too high, the CD bias change is higher than 0.1 μm. The main reason is that hydrogen peroxide is the main oxidant. When the hydrogen peroxide content is too low or too high, the etching reaction will be too slow or too fast during the entire reaction.

[0129] From the comparison between Examples 3 to 5 and Comparative Examples 3 to 4, it can be seen that when the content of the hydrogen peroxide stabilizer in the etching solution is within an appropriate range, the etching performance is excellent; when the content of the hydrogen peroxide stabilizer in the etching solution is too high, the pH of the etching solution increases, the cone angle becomes lower, and the increase in pH is also accompanied by the occurrence of titanium residue.

[0130] It can be seen from Comparative Examples 5 and 6 that the content of metal ion chelating agent in the etching solution is low, the cone angle becomes lower, the CD bias change of the etching solution during the etching process is higher than 0.1μm, and titanium residue exists in the etching process of the etching wafer containing copper-titanium metal film; the content of metal ion chelating agent in the etching solution is high, the cone angle becomes higher, and the CD bias change of the etching solution during the etching process is higher than 0.1μm.

[0131] It can be seen from Comparative Examples 7 and 8 that the content of metal corrosion inhibitor in the etching solution is high, the cone angle becomes lower, the CD bias change of the etching solution during the etching process is higher than 0.1 μm, and titanium residue exists during the etching process of the etching wafer containing the copper-titanium metal film.

[0132] It can be seen from Comparative Examples 9 and 10 that when no diphenyliodonium chloride is added to the etching solution or the content of diphenyliodonium chloride is low, titanium residue occurs during the etching process of the etching wafer containing the copper-titanium metal film.

[0133] In summary, the etching solution of the present invention, by adding appropriate amounts of hydrogen peroxide, nitric acid, a hydrogen peroxide stabilizer, a metal ion chelating agent, a metal corrosion inhibitor and diphenyliodonium chloride, each component cooperates with each other, so that it has the advantages of high safety, good stability, excellent etching performance, and the ability to meet high-precision processing requirements; when used in the etching process of an etching wafer containing a copper-titanium metal film, the pH stability during the etching process can be maintained, the uniformity of the etching can be ensured, and the phenomenon of uneven etching caused by pH changes can be avoided; the CD bias change of the etching solution during the etching process is less than 0.1 μm; during the entire service life of the etching solution, the etching CD and the slope angle remain basically unchanged, and there is no metal residue on the surface and no titanium residue.

[0134] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An etching solution, characterized in that: According to mass percentage, it includes the following components: 5wt%-10wt% of hydrogen peroxide, 4-6wt% of nitric acid, 0.1wt%-5wt% of hydrogen peroxide stabilizer, 0.1wt%-5wt% of metal ion chelating agent, 0.01wt%-5wt% of metal corrosion inhibitor, 0.3wt%-0.5wt% of diphenyliodonium chloride, and the balance is water.

2. The etching solution according to claim 1, characterized in that According to mass percentage, it includes the following components: 7-8wt% of hydrogen peroxide, 4.8-5.2wt% of nitric acid, 1wt%-2wt% of hydrogen peroxide stabilizer, 2wt%-5wt% of metal ion chelating agent, 0.5wt%-1wt% of metal corrosion inhibitor, 0.3wt%-0.5wt% of diphenyliodonium chloride, and the balance is water.

3. The etching solution according to claim 1, characterized in that The pH of the etching solution is 0.5-1.

5.

4. The etching solution according to claim 3, characterized in that The hydrogen peroxide stabilizer includes at least one of dipropylamine, n-butylamine, n-hexylamine, hexamethylenediamine, cyclohexylamine and diethylenetriamine.

5. The etching solution according to claim 3, characterized in that The metal ion chelating agent includes at least one of hydroxyethylidene diphosphonic acid, aminotrimethylene phosphonic acid, methylene diphosphonic acid, dipyridine carboxylic acid, aminotriacetic acid and glycolic acid.

6. The etching solution according to claim 3, characterized in that The metal corrosion inhibitor includes at least one of thiophene, thiazole, imidazole, pyrazole, monomethylimidazole, dimethylimidazole, trimethylimidazole, methylbenzotriazole, tetrazole and methyltetrazole.

7. The method for preparing the etching solution according to any one of claims 1 to 6, characterized in that: The steps include: The components are mixed evenly to obtain the etching solution.

8. An etching method, characterized in that: The etching solution according to any one of claims 1 to 6 is used to etch the etching wafer; the etching wafer comprises a substrate and a metal film arranged on the surface of the substrate, and the metal film comprises a copper metal film and a titanium metal film arranged on the surface of the copper metal film.

9. The etching method according to claim 8, characterized in that: The etching temperature is 25-35°C.

10. The etching method according to claim 8, characterized in that: The etching time is 100 to 200 seconds.

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