A copper etching solution and its preparation method, and an etching method for copper on a glass substrate.

Abstract

This invention discloses a copper etching solution and its preparation method, as well as an etching method for copper on glass substrates, belonging to the field of semiconductor display technology. By mass percentage, the copper etching solution comprises 1-15% inorganic acid, 4-10% peroxide, 4-10% organic acid and / or its salt, 0.5-5.0% chelating agent, 0.05-0.5% etching control agent, 0.1-0.5% surfactant, and 0.1-1.0% stabilizer, with the balance being water. The organic acid includes a first organic acid and a second organic acid; wherein the stability constant lgβn between the first organic acid and copper is ≤10, and the stability constant lgβn between the second organic acid and copper is 14-20. This copper etching solution is particularly suitable for etching copper with a thickness of 4-10 μm, not only obtaining the required etching morphology but also effectively controlling the etching rate and the loss of critical dimensions of the pattern, and has a large etching capacity, showing broad application prospects.

Description

Technical Field

[0001] This invention relates to the field of semiconductor display technology, and more specifically, to a copper etching solution and its preparation method, and an etching method for copper on a glass substrate. Background Technology

[0002] Mini / Micro LED direct-view technology is considered the ultimate display solution due to its advantages of self-illumination, high efficiency, low power consumption, high integration, high stability, and all-weather operation. COG (chip on glass) refers to directly bonding LED chips to a glass substrate and using TFT (thin-film transistor) driving to achieve the display. Compared to COB (chip on board), COG is smaller, has a simpler process, and is easier to simplify, miniaturize, and highly integrate. More importantly, COG, based on glass substrate technology, uses photolithography, semiconductor, and advanced copper processes, enabling the achievement of ultra-fine TFT driving structures over large areas.

[0003] Currently, the thickness of copper films on glass substrates ranges from 200nm to 4.5μm. With increasing demands for heat dissipation and conductivity, the copper film thickness is increasing (6-10μm). From a Micro LED technology perspective, future pixel pitches will be below P1, and even below P0.5. Simultaneously, the size of Micro LED crystal particles will decrease from 100 micrometers to 10 micrometers. At the same time, the linewidth and spacing of copper are becoming increasingly smaller.

[0004] Due to the design of ultra-fine circuit patterns, the requirements for etching effects such as side etching are becoming increasingly stringent. In the traditional hydrogen peroxide etching system, the increase in copper ion content will reduce the stability of the system and worsen the etching performance.

[0005] Copper etching typically employs etching systems using metal salts such as copper chloride and ferric chloride, but these systems present challenges in wastewater treatment and exhibit significant etching CD bias. Commonly used copper etching systems, such as sulfuric acid and hydrogen peroxide, also present some problems when applied to mini / micro LED copper etching, such as:

[0006] (1) The etching rate is too fast or too slow;

[0007] (2) It is difficult to control the side corrosion of lines with a thickness of 4-10μm;

[0008] (3) Since the copper thickness is 4-10μm, compared with the conventional copper thickness of about 600nm, its copper thickness is more than 6 times that of conventional products. For products of the same area, the copper ion content dissolved during the etching process is greater, and the small etching capacity is difficult to meet the production requirements.

[0009] In view of this, the present invention is hereby proposed. Summary of the Invention

[0010] One of the objectives of this invention is to provide a copper etching solution to solve the above-mentioned technical problems.

[0011] The second objective of this invention is to provide a method for preparing the aforementioned copper etching solution.

[0012] A third objective of this invention is to provide a method for etching copper on a glass substrate using the aforementioned copper etching solution.

[0013] This application can be implemented as follows:

[0014] In a first aspect, this application provides a copper etching solution, which, by mass percentage, comprises 1-15% inorganic acid, 4-10% peroxide, 4-10% organic acid and / or its salt, 0.5-5.0% chelating agent, 0.05-0.5% etching control agent, 0.1-0.5% surfactant, and 0.1-1.0% stabilizer, with the balance being water;

[0015] Organic acids include first organic acid and second organic acid; wherein, the stability constant lgβn of the first organic acid with copper is ≤10, and the stability constant lgβn of the second organic acid with copper is 14-20.

[0016] In an optional embodiment, the copper etching solution comprises 3-10% inorganic acid, 5-8% peroxide, 4-7% organic acid and / or its salt, 1.5-3.5% chelating agent, 0.1-0.3% etching control agent, 0.2-0.4% surfactant, and 0.3-0.6% stabilizer, with the balance being water.

[0017] In an optional embodiment, the first organic acid is a nitrogen-free organic acid having at least one or more carboxyl groups.

[0018] In an optional embodiment, the first organic acid includes at least one of a monocarboxylic acid and a dicarboxylic acid; wherein the monocarboxylic acid in the first organic acid includes at least one of formic acid, butyric acid, benzoic acid, glycolic acid and lactic acid; and / or, the dicarboxylic acid in the first organic acid includes at least one of oxalic acid, malonic acid, succinic acid, tartaric acid and malic acid.

[0019] In an optional embodiment, the first organic acid includes at least one of lactic acid, oxalic acid, and tartaric acid.

[0020] In an optional embodiment, the second organic acid is an organic acid containing a nitrogen atom.

[0021] In an optional embodiment, the second organic acid includes at least one of a monocarboxylic acid, a dicarboxylic acid, and a polycarboxylic acid; wherein the monocarboxylic acid in the second organic acid includes at least one of glutamic acid and arginine; and / or, the dicarboxylic acid in the second organic acid includes iminodiacetic acid; and / or, the polycarboxylic acid includes at least one of aminotriacetic acid and ethylenediaminetetraacetic acid.

[0022] In an optional embodiment, the second organic acid includes at least one of glutamic acid, iminodiacetic acid, and ethylenediaminetetraacetic acid.

[0023] In an optional embodiment, the inorganic acid is phosphoric acid; and / or, the peroxide is hydrogen peroxide.

[0024] In an optional embodiment, the chelating agent includes organic alcohol amine compounds.

[0025] In an optional embodiment, the chelating agent includes at least one selected from monoethanolamine, diethanolamine, triethanolamine, N,N-dimethylethanolamine, diethylene glycolamine, and 2-amino-2-methylpropanol.

[0026] In an optional implementation, the chelating agent is triethanolamine.

[0027] In an optional embodiment, the etching control agent is a tetrazolium compound, the structural formula of which is as follows: R is selected from at least one of H, CH3 and NH3.

[0028] In an optional embodiment, the etching control agent includes at least one of tetrazolium, 5-methyltetrazolium, and 5-aminotetrazolium.

[0029] In an optional embodiment, the etching control agent includes at least one of 5-methyltetrazole and 5-aminotetrazole.

[0030] In an optional embodiment, the surfactant is a block polyether nonionic surfactant; and / or, the stabilizer includes at least one of phenylurea, cyclohexylamine, 1-propanol, and ethylene glycol butyl ether.

[0031] In an optional embodiment, the block polyether is a polyether containing EO-PO-EO blocks.

[0032] In an optional embodiment, the molecular weight of the block polyether nonionic surfactant is 2000-5000.

[0033] In an optional embodiment, the stabilizer is phenylurea.

[0034] Secondly, this application provides a method for preparing a copper etching solution as described in any of the foregoing embodiments, comprising: mixing the components.

[0035] Thirdly, this application provides a method for etching copper on a glass substrate, comprising the following steps: etching copper on the glass substrate with the copper etching solution of any of the foregoing embodiments.

[0036] In an optional implementation, the thickness of the copper to be etched is 4-10 μm.

[0037] In an optional embodiment, etching is performed at 25-40°C for 3-5 minutes.

[0038] In an optional implementation, the etching temperature is 25-30°C.

[0039] The beneficial effects of this application include:

[0040] In this application, peroxides mainly serve as the main component for oxidizing and etching metals; inorganic acids enhance the oxidizing power of peroxides; the first organic acid and / or its salt maintains the acidity of the etching solution, and due to the low stability constant of the complex formed with Cu(II), the activation energy of the deposition reaction is low, the triggering speed is fast, which is beneficial for the rapid etching of copper; the second organic acid and / or its salt acts as a complexing agent, improving the etching performance; the etching control agent, on the one hand, avoids the accumulation of copper ions in the etching solution, which would cause the decomposition of hydrogen peroxide and affect the stability of the etching solution; on the other hand, the generated chelates are adsorbed on the copper... On the surface, it effectively controls the etching rate, reduces the loss of critical dimensions of the pattern, and maintains the stability of the surface contour; the chelating agent has a strong complexing ability for copper, reduces the risk of free copper ions decomposing hydrogen peroxide, and extends the life of the etching solution; it can also adjust the pH of the etching solution, control and stabilize the etching rate of copper, improve the copper etching life, and make the etched circuit obtain a good etched morphology; the surfactant can reduce the surface tension, improve the wettability of the etching solution on the substrate surface and improve the penetration of the etching solution into the high position of the substrate structure, so that the etching solution can fully contact the copper layer, accelerate the etching initiation reaction, and make the etching uniformity better.

[0041] This copper etching solution is particularly suitable for etching copper with a thickness of 4-10μm. It can not only obtain the required etching morphology, but also effectively control the etching rate and the loss of critical dimensions of the pattern. In addition, it has a large etching capacity and has broad application prospects. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0043] The copper etching solution and its preparation method provided in this application, as well as the etching method for copper on glass substrates, are described in detail below.

[0044] This application provides a copper etching solution, which, by mass percentage, comprises 1-15% inorganic acid, 4-10% peroxide, 4-10% organic acid and / or its salt, 0.5-5.0% chelating agent, 0.05-0.5% etching control agent, 0.1-0.5% surfactant, and 0.1-1.0% stabilizer, with the balance being water.

[0045] For reference, the mass percentage of the aforementioned inorganic acid may be, for example, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, or 15%, or any other value in the range of 1-15%.

[0046] The mass percentage of peroxide can be, for example, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, or 10%, or any other value in the range of 4-10%.

[0047] The mass percentage of organic acids and / or their salts may, for example, be 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, or 10%, or any other value in the range of 4-10%.

[0048] The mass percentage of the chelating agent can be, for example, 0.5%, 1%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, or 5.0%, or any other value in the range of 0.5-5.0%.

[0049] The mass percentage of the etching control agent can be, for example, 0.05%, 0.10%, 0.15%, 0.20%, 0.25%, 0.30%, 0.35%, 0.40%, 0.45%, or 0.5%, or any other value in the range of 0.05-0.5%.

[0050] The mass percentage of the surfactant can be, for example, 0.1%, 0.15%, 0.20%, 0.25%, 0.30%, 0.35%, 0.40%, 0.45%, or 0.5%, or any other value in the range of 0.1-0.5%.

[0051] The mass percentage of the stabilizer can be, for example, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, or 1.0%, or any other value in the range of 0.1-1.0%.

[0052] In some preferred embodiments, the copper etching solution comprises 3-10% (e.g., 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, or 10%) of inorganic acid, 5-8% (e.g., 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, or 8%) of peroxide, 4-7% (e.g., 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, or 7%) of organic acid and / or its salts, and 1.5-3.5% (e.g., 1.5%, 1.8%, 2.0%, 2.2%, 2.4%, 2.6%, 2.8%, 3.0%) of organic acid and / or its salts. The mixture contains 3.2% or 3.5% (e.g., chelating agent), 0.1-0.3% (e.g., 0.1%, 0.12%, 0.15%, 0.18%, 0.2%, 0.22%, 0.25%, 0.28%, or 0.3%) of etching control agent, 0.2-0.4% (e.g., 0.2%, 0.22%, 0.24%, 0.26%, 0.28%, 0.3%, 0.32%, 0.34%, 0.36%, 0.38%, or 0.4%) of surfactant, and 0.3-0.6% (e.g., 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.55%, or 0.6%) of stabilizer, with the balance being water.

[0053] Under this preferred formulation, a better copper etching effect can be obtained.

[0054] In this application, inorganic acids can enhance the oxidizing power of peroxides. Specifically, phosphoric acid is used as the inorganic acid, which, as a moderately strong acid, has excellent etching performance on copper films.

[0055] The peroxide used is hydrogen peroxide, which is used to oxidize and etch copper.

[0056] Organic acids and / or their salts can be understood as: organic acids only, or only the salts corresponding to organic acids (abbreviated as organic acid salts), or mixtures of organic acids and their salts.

[0057] In this application, organic acids include a first organic acid and a second organic acid, and organic acid salts are the salts corresponding to the first organic acid (such as sodium salts) and the second organic acid (such as sodium salts), respectively.

[0058] Among them, the stability constant lgβn of the first organic acid with copper is ≤10 (such as 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, or other constants within the range of ≤10), and the stability constant lgβn of the second organic acid with copper is 14-20 (such as 14, 15, 16, 17, 18, 19 or 20, or other constants within the range of 14-20).

[0059] The first organic acid and / or its salt, possessing the aforementioned characteristics, not only adjusts the pH of the etching solution and maintains its acidity, but also, due to the low stability constant of the complex formed with Cu(II), results in a low activation energy and rapid triggering rate for the etching reaction. Combined with the effects of block polyether, this facilitates rapid copper etching. The second organic acid and / or its salt, also possessing the aforementioned characteristics, acts as a complexing agent, increasing the amount of copper dissolved, improving etching performance, and enhancing etching stability.

[0060] In some alternative embodiments, the first organic acid is a nitrogen-free organic acid having at least one carboxyl group.

[0061] Specifically, the first organic acid may include at least one of monocarboxylic acids and dicarboxylic acids. The monocarboxylic acid in the first organic acid may include at least one of formic acid, butyric acid, benzoic acid, glycolic acid, and lactic acid; the dicarboxylic acid in the first organic acid may include at least one of oxalic acid, malonic acid, succinic acid, tartaric acid, and malic acid.

[0062] In some preferred embodiments, the first organic acid includes at least one of lactic acid, oxalic acid, and tartaric acid.

[0063] In some alternative embodiments, the second organic acid is an organic acid containing a nitrogen atom.

[0064] Specifically, the second organic acid may include at least one of monocarboxylic acids, dicarboxylic acids, and polycarboxylic acids (three or more). Specifically, the monocarboxylic acid in the second organic acid may include at least one of glutamic acid and arginine; the dicarboxylic acid in the second organic acid includes iminodiacetic acid; and the polycarboxylic acid includes at least one of aminotriacetic acid and ethylenediaminetetraacetic acid.

[0065] In some preferred embodiments, the second organic acid includes at least one of glutamic acid, iminodiacetic acid, and ethylenediaminetetraacetic acid.

[0066] The aforementioned second organic acid and / or its salt can utilize carboxyl-oxygen coordinating atoms to effectively chelate metal ions and reduce the intrusion of the etching solution and over-etching attack on copper during the etching process, ensuring a wider operating window and meeting the required critical dimension loss.

[0067] For reference, the mass ratio of the first organic acid (the first organic acid and / or its salt) to the second organic acid (the second organic acid and / or its salt) may be from 1:2 to 2:1.

[0068] In this application, the chelating agent includes organic alcohol amine compounds, which may, by way of example, include at least one of monoethanolamine, diethanolamine, triethanolamine, N,N-dimethylethanolamine, diethylene glycolamine, and 2-amino-2-methylpropanol.

[0069] In some preferred embodiments, the chelating agent is triethanolamine.

[0070] The aforementioned chelating agent has a strong complexing ability for copper, which can reduce the risk of free copper ions decomposing hydrogen peroxide and extend the life of the etching solution; in addition, it can also adjust the pH value of the etching solution, stabilize the etching rate of copper, and enable the etching profile to meet the requirements.

[0071] In this application, the etching control agent is a tetrazolium compound, and the structural formula of the tetrazolium compound is as follows: R is selected from at least one of H, CH3 and NH3.

[0072] For example, the etching control agent described above may include at least one of tetrazolium, 5-methyltetrazolium, and 5-aminotetrazolium.

[0073] In some preferred embodiments, the etching control agent includes at least one of 5-methyltetrazole and 5-aminotetrazole.

[0074] The aforementioned tetrazolium compounds belong to nitrogen-containing (rich) heterocyclic compounds. Due to the large π-bonds formed by the five atoms on the ring, the substances are relatively stable. The five-membered ring structure is close to a pentagon, and the entire group exhibits good coplanarity. As a multidentate ligand with multiple coordination sites, it can act as both a chelating ligand and a bridging ligand, possessing flexible and diverse coordination modes. In particular, the introduction of various substituents at the 5-position in 5-substituted tetrazolium greatly enriches the coordination modes of tetrazolium ligands. Forming coordination compounds with copper, these compounds adsorb onto the copper surface, preventing further etching of copper. This effectively controls the overall etching rate of copper, maintains the stability of the etching performance of the etching solution at each stage of use, and thus obtains the desired etching morphology. Considering requirements such as water solubility, 5-methyltetrazole and / or 5-aminotetrazole are preferred.

[0075] In this application, the surfactant is a block polyether nonionic surfactant to reduce surface tension, allowing the etching solution to fully contact the copper layer and resulting in better etching uniformity.

[0076] Specifically, the block polyether is a polyether containing EO-PO-EO blocks, and may include, for example, at least one of Pluronic PE3100, Pluronic PE6100, Pluronic PE6400, RPE1740, Pluronic PE6200 and Pluronic PE8100, preferably at least one of Pluronic PE6100, Pluronic PE6200 and Pluronic PE8100.

[0077] The combination of the aforementioned block polyether with a first organic acid and / or its salt facilitates rapid etching of copper.

[0078] In an optional embodiment, the molecular weight of the block polyether nonionic surfactant is 2000-5000.

[0079] It should be noted that if the molecular weight of the surfactant is too large, it will result in excessive foaming; if the molecular weight of the surfactant is too small, it will result in insufficient wetting and surface tension.

[0080] In this application, the stabilizer may include at least one of phenylurea, cyclohexylamine, 1-propanol and ethylene glycol butyl ether, preferably phenylurea.

[0081] The aforementioned stabilizers can improve the stability of peroxides and extend the lifespan of the etching solution.

[0082] Continuing from the above, in this application, peroxides mainly serve as the main component for oxidizing and etching metals; inorganic acids enhance the oxidizing power of peroxides; the first organic acid and / or its salt maintains the acidity of the etching solution, and due to the low stability constant of the complex formed with Cu(II), the activation energy of the deposition reaction is low, the triggering speed is fast, which is beneficial for the rapid etching of copper; the second organic acid and / or its salt acts as a complexing agent, improving etching performance; the etching control agent, on the one hand, prevents the accumulation of copper ions in the etching solution from causing the decomposition of hydrogen peroxide and affecting the stability of the etching solution; on the other hand, the generated chelates are adsorbed on... On the copper surface, the etching rate is effectively controlled, the loss of critical dimensions of the pattern is reduced, and the stability of the surface contour is maintained. The chelating agent has a strong complexing ability with copper, reducing the risk of free copper ions decomposing hydrogen peroxide and extending the life of the etching solution. It can also adjust the pH of the etching solution, control and stabilize the etching rate of copper, improve the copper etching life, and make the etched circuit obtain a good etched morphology. The surfactant can reduce the surface tension, improve the wettability of the etching solution on the substrate surface and improve the penetration of the etching solution into the high position of the substrate structure, so that the etching solution can fully contact the copper layer, accelerate the etching initiation reaction, and make the etching uniformity better.

[0083] Accordingly, this application also provides a method for preparing the above-mentioned copper etching solution, that is, simply by mixing the components.

[0084] Preferably, the mixing process can be accelerated by stirring to form a uniform etching solution.

[0085] In addition, this application also provides a method for etching copper on a glass substrate, which may include the following steps: etching the copper on the glass substrate with the above-mentioned copper etching solution.

[0086] The copper etching solution provided in this application is particularly suitable for etching copper with a thickness of 4-10 μm. For example, the thickness of the copper to be etched can be 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm or 10 μm, or any other value in the range of 4-10 μm.

[0087] By etching copper with a thickness of 4-10 μm using the above-mentioned etching solution, not only can superior etching morphology be obtained, but also the etching rate can be effectively controlled, the amount of material can be reduced, and the etching capacity can be increased.

[0088] For reference, etching can be performed at 25-40°C (e.g., 25°C, 30°C, 35°C, or 40°C) for 3-5 minutes (e.g., 3 minutes, 3.5 minutes, 4 minutes, 4.5 minutes, or 5 minutes). Preferably, the etching temperature is 25-30°C.

[0089] Etching at the preferred temperature will not cause hydrogen peroxide decomposition and will make the entire etching process stable and controllable.

[0090] In practice, the workpiece to be etched, with a copper layer thickness of 4-10 μm, can be placed in the aforementioned copper etching solution and etched under the conditions described above. This method yields the desired etch morphology and exhibits excellent etching performance.

[0091] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0092] Examples 1-9

[0093] Examples 1-9 provide nine copper etching solutions, all prepared using the same method: oxidant, inorganic acid, organic acid, etching control agent, chelating agent, surfactant, stabilizer, and water are mixed at 25°C for 40 minutes according to the specified ratio, and then filtered through a 0.2μm filter.

[0094] The formulations of the copper etching solutions provided in Examples 1-9 are shown in Table 1:

[0095] Table 1 Formulation Composition

[0096]

[0097]

[0098] Comparative Example 1

[0099] This comparative example provides a copper etching solution, which differs from Example 1 in that its components are different.

[0100] The copper etching solution comprises, by mass percentage: 5% hydrogen peroxide, 10% phosphoric acid, 2% lactic acid, 2% tartaric acid, 0.1% 5-aminotetrazole, 1.5% triethanolamine, 0.2% PE6100, and 0.5% phenylurea, with the balance being water.

[0101] Specifically, the difference from Example 1 is that there is no second organic acid (this part is made up by water).

[0102] Comparative Example 2

[0103] This comparative example provides a copper etching solution, which differs from Example 1 in that its components are different.

[0104] The copper etching solution comprises, by mass percentage: 5% hydrogen peroxide, 10% phosphoric acid, 2% iminodiacetic acid, 0.1% 5-aminotetrazole, 1.5% triethanolamine, 0.2% PE6100, and 0.5% phenylurea, with the balance being water.

[0105] Specifically, the difference from Example 1 is that it lacks the first organic acid (this part is made up by water).

[0106] Comparative Example 3

[0107] This comparative example provides a copper etching solution, which differs from Example 1 in that its components are different.

[0108] The copper etching solution comprises, by mass percentage: 5% hydrogen peroxide, 10% phosphoric acid, 2% lactic acid, 2% tartaric acid, 2% iminodiacetic acid, 1.5% triethanolamine, 0.2% PE6100, and 0.5% phenylurea, with the balance being water.

[0109] Specifically, the difference from Example 1 is that it does not contain an etching control agent (this part is made up by water).

[0110] Comparative Example 4

[0111] This comparative example provides a copper etching solution, which differs from Example 1 in that its components are different.

[0112] The copper etching solution comprises, by mass percentage: 5% hydrogen peroxide, 10% phosphoric acid, 2% lactic acid, 2% tartaric acid, 2% iminodiacetic acid, 0.1% benzotriazole, 1.5% triethanolamine, 0.2% PE6100, and 0.5% phenylurea, with the balance being water.

[0113] Specifically, the difference from Example 1 is that the etching control agent is replaced by benzotriazole instead of 5-aminotetrazole.

[0114] Comparative Example 5

[0115] The copper etching solution comprises, by mass percentage: 5% hydrogen peroxide, 10% phosphoric acid, 2% lactic acid, 2% tartaric acid, 2% iminodiacetic acid, 0.04% 5-aminotetrazole, 1.5% triethanolamine, 0.2% PE6100, and 0.5% phenylurea, with the balance being water.

[0116] Specifically, the difference from Example 1 is that the amount of 5-aminotetrazole in the etching inhibitor is reduced from 0.1% to 0.04%, and the remaining amount is adjusted accordingly with water.

[0117] Comparative Example 6

[0118] This comparative example provides a copper etching solution, which differs from Example 1 in that its components are different.

[0119] The copper etching solution comprises, by mass percentage: 5% hydrogen peroxide, 10% phosphoric acid, 2% lactic acid, 2% tartaric acid, 2% iminodiacetic acid, 0.1% 5-aminotetrazole, 0.4% triethanolamine, 0.2% PE6100, and 0.5% phenylurea, with the balance being water.

[0120] Specifically, the difference from Example 1 is that the amount of triethanolamine in the chelating agent is reduced from 1.5% to 0.4%, and the remaining amount is adjusted accordingly with water.

[0121] Comparative Example 7

[0122] The copper etching solution comprises, by mass percentage: 5% hydrogen peroxide, 10% phosphoric acid, 2% lactic acid, 2% tartaric acid, 2% iminodiacetic acid, 0.1% 5-aminotetrazole, 1.5% triethanolamine, and 0.5% phenylurea, with the balance being water.

[0123] Specifically, the difference from Example 1 is that it does not contain surfactants, and the remaining amount is adjusted accordingly with water.

[0124] Test case

[0125] The etching points, critical dimension loss due to over-etching, copper dissolution, etching stability, and etching uniformity of the copper etching solutions provided in Examples 1-9 and Comparative Examples 1-7 were evaluated, and the test results are shown in the table.

[0126] Test method: The exposed and developed substrate (copper thickness of about 5μm) was placed in the etching solution. The etching temperature was set to 30℃ and the time was 4min. After etching, its various properties were tested.

[0127] (1) Etching points: Immerse the blank copper substrate (without resist coating and development) in 30℃ etching solution. The etching points are the ones that have just been completely etched.

[0128] ○: 3-5min; ×: <3min or >5min.

[0129] (2) Critical dimension loss due to over-etching: After removing the substrate that has been over-etched by 50% (etching time is 1.5 times the etch point), it is dried and the line width is observed under a microscope.

[0130] ○: CD loss≤4μm; ×: CD loss>4μm.

[0131] (3) Copper dissolution amount: Add a certain concentration of copper powder to the copper etching solution and test its etching rate and critical dimension loss due to over-etching. The critical point (the content of copper ions in the etching solution before failure) is the copper dissolution amount / lifetime of the etching solution.

[0132] ○: Copper content > 8000ppm; ×: Copper content ≤ 8000ppm.

[0133] (4) Etching uniformity COV: The 20cm×20cm substrate to be etched was immersed in the etching solution at 30°C for 4 minutes. After drying, the COV (coefficient of variation) of the critical dimension loss of the etching was tested by the 16-point method.

[0134] ○: COV>90%; ×: COV≤90%.

[0135] Table 2 Results of Etching Solution Performance Tests

[0136]

[0137]

[0138] As can be seen from the data in Table 2, the copper etching solution provided in this application embodiment is ideal for etching 5μm thick copper with a line width / spacing within 10μm / 10μm nodes. Its etching points are relatively suitable and controllable, with minimal lateral etching, long etching solution life, and excellent etching uniformity.

[0139] The copper etching solution provided in this application can achieve ideal etching results, with a copper dissolution amount of up to 9000 ppm or more. When the etching solution does not contain a specific combination of additives, the etching rate and etching uniformity are difficult to control, the lateral etching is too large, and the etching stability is poor.

[0140] In summary, the copper etching solution provided in this application is suitable for etching copper with a thickness of 4-10μm. It can not only obtain the required etching morphology, but also effectively control the etching rate and the loss of critical dimensions of the pattern. Furthermore, it has a large etching capacity and broad application prospects.

[0141] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An application of a copper etching solution, characterized in that, The copper etching solution is used to etch copper on a glass substrate; the thickness of the copper to be etched is 4-10 μm. The copper etching solution comprises, by mass percentage, 1-15% inorganic acid, 4-10% peroxide, 4-10% organic acid and / or its salt, 0.5-5.0% chelating agent, 0.05-0.5% etching control agent, 0.1-0.5% surfactant, and 0.1-1.0% stabilizer, with the balance being water; The organic acid is composed of a first organic acid and a second organic acid; wherein the first organic acid is selected from at least one of lactic acid, oxalic acid and tartaric acid; and the second organic acid is selected from at least one of glutamic acid, iminodiacetic acid and ethylenediaminetetraacetic acid. The inorganic acid is phosphoric acid; the peroxide is hydrogen peroxide; the chelating agent is triethanolamine; The etching control agent is selected from at least one of 5-methyltetrazole and 5-aminotetrazole; The surfactant is selected from at least one of PE6100, PE6200 and PE8100; The stabilizer is phenylurea.

2. The application according to claim 1, characterized in that, The copper etching solution comprises 3-10% inorganic acid, 5-8% peroxide, 4-7% organic acid and / or its salt, 1.5-3.5% chelating agent, 0.1-0.3% etching control agent, 0.2-0.4% surfactant, and 0.3-0.6% stabilizer, with the balance being water.

3. The application according to claim 1 or 2, characterized in that, The preparation method of the copper etching solution includes: mixing the components.

4. A method for etching copper onto a glass substrate, characterized in that, The method includes the following steps: etching copper on a glass substrate with the copper etching solution used in any one of claims 1 to 3.

5. The etching method according to claim 4, characterized in that, Etching is performed at 25-40℃ for 3-5 minutes.

6. The etching method according to claim 5, characterized in that, The etching temperature is 25-30℃.

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