A two-dosage form copper etching solution and a preparation method thereof
By storing hydrogen peroxide and acidic complex components separately and constructing a stable acidic complex framework system, the problems of storage stability and etching uniformity of copper etching solution in fine circuit processing were solved, thereby achieving stability of etching rate and improvement of copper surface flatness.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SUZHOU BOYANG CHEM
- Filing Date
- 2026-04-28
- Publication Date
- 2026-07-28
AI Technical Summary
Existing copper etching solutions suffer from poor storage stability, unstable etching rate, difficulty in controlling lateral etching, and insufficient copper surface flatness in fine circuit processing. In particular, the long-term coexistence of organic acids, complexing agents, and nitrogen-containing conditioning components can easily lead to hydrogen peroxide decomposition and local complexation imbalance.
A two-component copper etching solution was prepared by storing hydrogen peroxide and acidic complexing components separately. An acidic complexing framework system was constructed by synergistically using gluconic acid, aminotrimethylenephosphonic acid, lactic acid, phosphoric acid, methanesulfonic acid, and aluminum-containing hybrid precursors. Acid was added stepwise, temperature was controlled, and aging and filtration were performed to form a stable copper etching solution.
It improves the storage stability and usage consistency of copper etching solution, ensures stable etching rate, reduces side etching, enhances etching uniformity and copper surface flatness, and meets the requirements of fine circuit processing.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of copper etching solution technology, and specifically to a two-component copper etching solution and its preparation method. Background Technology
[0002] Copper and copper alloys, due to their excellent electrical and thermal conductivity and ductility, are widely used in printed circuit boards, lead frames, semiconductor packaging substrates, and electronic interconnects. In the process of forming circuit patterns using subtractive etching, copper etching solutions need to selectively remove exposed copper layers within a short time, while also ensuring uniform etching within the board, neatness of circuit edges, control of side etching, and smoothness of the etched copper surface. With the continuous development of high-density interconnects, fine linewidth / pitch, and thin copper foil processes, the industry has placed higher demands on copper etching solutions. These solutions must not only have a fast and stable etching rate but also minimize slag, residue, surface roughening, and dimensional compensation fluctuations to meet the requirements of fine circuit processing for processing window and process stability.
[0003] Existing patents have proposed various improvements to copper etching solutions. For example, patent application CN111733419A discloses an acidic etching solution and its electrolytic copper extraction and recycling apparatus and method. It uses divalent copper, trivalent ferric ions, dimethyl ferrous ions, hydrogen ions, and high-concentration chloride ions as its main components, and incorporates allyl thiourea to achieve etching and cyclic regeneration, indicating that the chlorination system has relatively mature technology accumulation in continuous use and recycling. However, its disclosed formula shows that this solution is essentially still a high-chloride-ion acidic system. Patent application CN112055759A discloses an etching solution for copper foil containing hydrogen peroxide, sulfuric acid, and specific azole compounds, mainly suppressing the side etching of copper wiring by introducing azole components. Patent application CN113718256A discloses a copper etching solution for wafer-level packaging. Through a compound of organic acid, amine compounds containing carboxylic acid groups, amide surfactants, organophosphorus compounds, and hydrogen peroxide, the CD-loss is controlled below 300 nm. Patent application CN116497355A discloses an acidic copper etching solution. Through a combination of inorganic acid, oxidant, imidazoline corrosion inhibitor, 2-ethylhexyl diphenyl phosphate, and acetone, it improves the etching rate, reduces side etching and residue, and exhibits some adaptability to etching temperature fluctuations.
[0004] However, a review of the published information in the aforementioned patent applications reveals that improvements in existing technologies primarily focus on single or localized performance aspects such as lateral etching suppression, selective etching of specific film layers, temperature fluctuation adaptability, or recyclability. For acidic copper peroxide etching systems suitable for fine circuit fabrication, a systematic optimization of the entire technical chain—including "solution storage stability - working solution usage stability - system fluctuations after copper ion accumulation - multi-component compatibility sequence and controllability of the solution formation process"—is lacking. Especially when organic acids, complexing agents, nitrogen-containing regulating components, phosphonic acid / phosphonate stabilizing components, and interface conditioning aids are introduced into the system simultaneously, prolonged coexistence of these components or improper control of the feeding sequence and temperature conditions can easily lead to premature decomposition of hydrogen peroxide, local complexation imbalance, uneven interface spreading, and even the formation of trace agglomerates or sediment. This, in turn, affects the stability of the etching rate, board uniformity, lateral etching amount, and the smoothness of the etched copper surface.
[0005] Therefore, there is a need to provide a two-component copper etching solution and its preparation method to solve the problems existing in the prior art. Summary of the Invention
[0006] In view of this, the present invention provides a two-component copper etching solution and its preparation method, which can achieve good storage stability of the etching solution, stable etching rate, less lateral etching and high copper surface flatness.
[0007] The specific solution of this invention is as follows: a method for preparing a two-component copper etching solution, comprising the following steps: Step S1: Mix deionized water, ethylene glycol monobutyl ether, and hydrogen peroxide aqueous solution to obtain agent A; Step S2: Deionized water, gluconic acid aqueous solution, aminotrimethylene phosphonic acid, lactic acid, triisopropanolamine, γ-glycidyl etheroxypropyltrimethoxysilane and aluminum lactate are mixed and reacted to obtain an aluminum-containing hybrid precursor. Step S3: Add aqueous solution of first phosphoric acid, methanesulfonic acid and lactic acid to the aluminum-containing hybrid precursor, followed by the addition of triisopropanolamine, aqueous solution of second phosphoric acid, 5-aminotetrazole and deionized water, and after aging and filtration, obtain agent B; Step S4: Mix agent A, agent B and deionized water to obtain a two-component copper etching solution.
[0008] In this invention, agent A serves as the oxidizing component system. The hydrogen peroxide aqueous solution is prepared and stored separately from agent B. This isolates the oxidizing component from the acidic complexing component, the aluminum-containing hybrid component, and the nitrogen-containing regulating component during storage. This effectively reduces the probability of slow side reactions between hydrogen peroxide and the organic and complexing components in the system during storage, while also reducing the decomposition of hydrogen peroxide induced by metal ions or impurities. Therefore, the risk of system activity decaying over storage time is reduced, and fluctuations in viscosity, acidity, and effective oxidizing capacity are minimized. This contributes to improving the storage stability of the etching solution and provides a foundation for obtaining a more stable etching rate during use.
[0009] In this invention, an acidic complex framework system is synergistically constructed using gluconic acid aqueous solution, aminotrimethylenephosphonic acid, lactic acid, phosphoric acid aqueous solution, methanesulfonic acid, and an aluminum-containing hybrid precursor. Glucolic acid, lactic acid, and aminotrimethylenephosphonic acid provide multi-site coordination or complexation, enhancing the capture and stabilization of copper ions generated during etching. Phosphoric acid aqueous solution and methanesulfonic acid together provide an acidic environment and participate in the regulation of the system's ion balance, allowing the oxidation-dissolution process on the copper surface to continue. The aluminum-containing hybrid precursor helps improve the spatial distribution uniformity and interfacial dispersion ability of the complex framework. The synergistic effect of these components reduces the risk of redeposition, precipitation, or local reaction imbalance caused by excessively high copper ion concentrations in local areas, enhances the system's complexation and dispersion capabilities for copper ions, and thus helps improve the continuity, stability, and uniformity of the etching process.
[0010] In this invention, the B-agent system is constructed by adding phosphoric acid aqueous solution in two stages, and triisopropanolamine is used for adjustment. This allows for a smoother introduction of acidic components into the system, reducing local acidity abrupt changes, local exothermic reactions, and precursor structural inhomogeneities caused by a single acid addition. This facilitates the gradual coupling of the aluminum-containing hybrid structure with the acidic complex system, forming a more stable system environment. Triisopropanolamine can further regulate the acid-base balance and local complexation state of the system, thereby reducing microscopic inhomogeneities caused by excessively rapid local reactions. The addition of 5-aminotetrazole allows it to regulate the reaction at the copper / etching solution interface, improving the reaction consistency of active sites, inhibiting excessively rapid etching in local areas, and resulting in more uniform copper surface dissolution. This, in turn, helps improve copper surface smoothness and reduce lateral etching.
[0011] Preferably, in step S1, agent A comprises the following components by mass: 23-44 parts of deionized water, 7-14 parts of ethylene glycol monobutyl ether, and 145-170 parts of hydrogen peroxide aqueous solution.
[0012] Preferably, the concentration of the hydrogen peroxide aqueous solution is 35 wt%, the concentration of the gluconic acid aqueous solution is 50 wt%, and the concentrations of the first phosphoric acid aqueous solution and the second phosphoric acid aqueous solution are both 85 wt%.
[0013] It helps to control the actual amount of each active component added and the matching relationship between acidity, oxidation capacity and complexing capacity in the system, and reduces the ratio deviation caused by fluctuations in raw material concentration, thereby helping to improve the batch consistency of the product and the performance stability during use.
[0014] Preferably, in step S2, the aluminum-containing hybrid precursor comprises, by mass, the following components: 40-65 parts deionized water, 12-25 parts gluconic acid aqueous solution, 1.5-5 parts aminotrimethylenephosphonic acid, 3-8 parts lactic acid, 1-3 parts triisopropanolamine, 2.5-7 parts γ-glycidyl etheroxypropyltrimethoxysilane, and 1.5-5 parts aluminum lactate.
[0015] Preferably, in step S2, the conditions for the mixing reaction are as follows: the temperature is raised to 35-50℃, and the mixture is stirred at a speed of 180-220 rpm; the dropping rate of the γ-glycidyl etheroxypropyltrimethoxysilane is 0.5-1.5 g / min, and the reaction is maintained at this temperature for 40-70 min after the addition is complete; then the temperature is raised to 50-65℃, and aluminum lactate is added in 2-5 batches, with an interval of 3-8 min between each batch; after the aluminum lactate is added, the stirring speed is increased to 240-320 rpm, and the reaction continues for 25-50 min.
[0016] Preferably, in step S3, when adding the first phosphoric acid aqueous solution, methanesulfonic acid and lactic acid, the temperature is controlled at 18-25°C and the stirring speed is 150-160 rpm.
[0017] By first constructing an aluminum-containing hybrid precursor and then introducing an acidic framework component, the organosilicon component, aluminum source, and organic acid component in the precursor can first form a relatively uniform dispersion or coordination state, and then gradually couple with the subsequent acidic component. This method helps to avoid local condensation inhomogeneity, coordination imbalance, or micro-region aggregation caused by premature addition of acidic components, thereby improving the overall homogeneity and stability of the system.
[0018] Preferably, in step S3, when adding triisopropanolamine, aqueous solution of second phosphoric acid, 5-aminotetrazole and deionized water, an ice-water bath is used to control the temperature so that the system temperature is 25-30°C.
[0019] Preferably, in step S3, 5-aminotetrazole and deionized water are added, stirred for 25-30 minutes, and then aged at room temperature for 3-6 hours.
[0020] By employing a stepwise acid addition, temperature-controlled addition of triisopropanolamine, and aging filtration, the B-agent system undergoes a relatively mild acidification, complexation, and structural adjustment process during construction. This avoids short-term concentration peaks, microphase separation, or unstable particle formation caused by excessively rapid reactions in localized areas. After aging, the complexation and dispersion states within the system further stabilize, thereby improving the homogeneity, storage stability, and processing consistency of the B-agent system during final use.
[0021] Preferably, in step S4, agent B is first mixed with 150-225 parts of deionized water and stirred for 8-10 minutes for pre-dilution. Then agent A is added and mixed for another 5-6 minutes. Finally, 75-150 parts of deionized water are added and the mixture is stirred in a static mixer at 20-22°C for 10 minutes to obtain a two-component copper etching solution.
[0022] By first diluting agent B, then adding agent A, and finally adding the remaining water, the local concentration of the acidic complexing component in agent B can be reduced. This provides a better buffer when the system comes into contact with agent A, thereby reducing the intensity and concentration fluctuations of the local reaction caused by the instantaneous contact between hydrogen peroxide and the acidic component. Adding the remaining deionized water then helps to further adjust the system to a suitable concentration range for use. This preparation sequence improves the mixing uniformity and formulation stability of the final etching solution and helps ensure the consistency of etching rate and morphology during actual use.
[0023] To achieve the above objectives, the present invention also provides a two-component copper etching solution prepared by the above-described method for preparing a two-component copper etching solution.
[0024] Preferably, agent B comprises the following components: 120.4-203.7 parts deionized water, 12-25 parts gluconic acid aqueous solution, 1.5-5 parts aminotrimethylenephosphonic acid, 20-35 parts lactic acid, 9-20 parts triisopropanolamine, 2.5-7 parts γ-glycidyl etheroxypropyltrimethoxysilane, 1.5-5 parts aluminum lactate, 125-180 parts phosphoric acid aqueous solution, 6-15 parts methanesulfonic acid, and 0.15-0.6 parts 5-aminotetrazole.
[0025] The components of this invention, using the above-mentioned weight proportions, enable the two-component copper etching solution to achieve better overall performance.
[0026] The above-described technical solution of the present invention has at least the following beneficial effects: 1. The present invention adopts the method of preparing and storing Agent A and Agent B separately and mixing them before use, which can reduce the risk of premature reaction and decomposition of hydrogen peroxide and acidic complex components, thereby helping to improve the storage stability and usage consistency of the system.
[0027] 2. This invention constructs a composite system with both acidic dissolving ability and copper ion complexing and dispersing ability through the synergistic effect of gluconic acid, aminotrimethylenephosphonic acid, lactic acid, phosphoric acid, methanesulfonic acid and aluminum-containing hybrid components. This system can reduce precipitation, redeposition or reaction imbalance caused by local enrichment of copper ions, thereby helping to improve the stability of the etching process, the continuous stability of the etching rate and the etching uniformity.
[0028] 3. This invention reduces the problems of excessively rapid local reactions and system inhomogeneity by synergistically controlling the construction of aluminum-containing hybrid precursors, stepwise acid addition, temperature control, aging filtration and final preparation sequence; at the same time, 5-aminotetrazole helps to improve the reaction consistency of the etching interface, thereby helping to obtain better copper surface flatness, less side etching and higher processing consistency. Detailed Implementation
[0029] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments.
[0030] Example 1 Add 40g of deionized water to a clean mixing tank, turn on the stirrer, control the temperature at 20℃, slowly add 10g of ethylene glycol monobutyl ether, stir for 10min until the mixture is uniform, then slowly add 150g of 35wt% hydrogen peroxide aqueous solution under light-protected conditions, and continue stirring for 20min to obtain agent A.
[0031] Add 50g of deionized water to the reactor, heat to 45℃, and stir at 200rpm. Then, add 20g of 50wt% gluconic acid aqueous solution, 3g of aminotrimethylenephosphonic acid, 6g of lactic acid, and 2g of triisopropanolamine in sequence. After stirring evenly, add 5g of γ-glycidoxypropyltrimethoxysilane dropwise at a rate of 1g / min. After the addition is complete, keep the reaction temperature at 60min. Then, heat to 60℃ and add 3g of aluminum lactate in three batches, with an interval of 5min between each batch. After the addition is complete, increase the stirring speed to 300rpm and continue the reaction for 40min to obtain the aluminum-containing hybrid precursor.
[0032] 100g of an 85wt% aqueous solution of phosphoric acid was slowly added to the aluminum-containing hybrid precursor under stirring conditions of 25℃ and 150rpm. Then, 10g of methanesulfonic acid and 24g of lactic acid were added, and the mixture was stirred for 20min. The temperature of the system was controlled by an ice-water bath to keep it below 30℃. 13g of triisopropanolamine was slowly added dropwise. After the addition was complete, 50g of an 85wt% aqueous solution of phosphoric acid was slowly added, and the mixture was stirred for another 20min. Then, 0.5g of 5-aminotetrazolium was added, followed by 113.5g of deionized water. The mixture was stirred for 30min, and then aged at room temperature for 4h. The mixture was then filtered through a 0.05μm polytetrafluoroethylene membrane to obtain agent B.
[0033] First, mix 300g of agent B with 187.5g of deionized water and stir for 10 minutes for pre-dilution. Then, add 150g of agent A and continue mixing for 5 minutes. Finally, add 112.5g of deionized water and mix at 20°C using a static mixer for 10 minutes to obtain a two-component copper etching solution.
[0034] Example 2 Add 32g of deionized water to a clean mixing tank, turn on the stirrer, control the temperature at 18℃, slowly add 8g of ethylene glycol monobutyl ether, stir for 10min until the mixture is uniform, then slowly add 160g of 35wt% hydrogen peroxide aqueous solution under light-protected conditions, and continue stirring for 20min to obtain agent A.
[0035] Add 60g of deionized water to the reactor, heat to 40℃, and stir at 180rpm. Then, add 18g of 50wt% gluconic acid aqueous solution, 2.5g of aminotrimethylenephosphonic acid, 5g of lactic acid, and 1.5g of triisopropanolamine in sequence. After stirring evenly, add 4g of γ-glycidoxypropyltrimethoxysilane dropwise at a rate of 0.8g / min. After the addition is complete, keep the reaction at the temperature for 45min. Then, heat to 55℃ and add a total of 2.5g of aluminum lactate in two batches, with an interval of 8min between each batch. After the addition is complete, increase the stirring speed to 260rpm and continue the reaction for 30min to obtain the aluminum-containing hybrid precursor.
[0036] 90g of an 85wt% aqueous solution of phosphoric acid was slowly added to the aluminum-containing hybrid precursor under stirring conditions of 20℃ and 150rpm. Then, 8g of methanesulfonic acid and 18g of lactic acid were added, and the mixture was stirred for 20min. The temperature of the system was controlled by an ice-water bath to keep it below 28℃. 11.5g of triisopropanolamine was slowly added dropwise. After the addition was complete, 40g of an 85wt% aqueous solution of phosphoric acid was slowly added, and the mixture was stirred for another 15min. 0.3g of 5-aminotetrazolium was added, followed by 138.7g of deionized water. The mixture was stirred for 25min, and then aged at room temperature for 6h. The mixture was then filtered through a 0.05μm polytetrafluoroethylene filter membrane to obtain agent B.
[0037] First, mix 300g of agent B with 180g of deionized water and stir for 8 minutes to pre-dilute. Then, add 150g of agent A and continue mixing for 5 minutes. Finally, add 120g of deionized water and mix for 10 minutes at 22°C using a static mixer to obtain a two-component copper etching solution.
[0038] Example 3 Add 36g of deionized water to a clean mixing tank, turn on the stirrer, control the temperature at 20℃, slowly add 9g of ethylene glycol monobutyl ether, stir for 10min until the mixture is uniform, then slowly add 155g of 35wt% hydrogen peroxide aqueous solution under light-protected conditions, and continue stirring for 20min to obtain agent A.
[0039] Add 45g of deionized water to the reactor, heat to 48℃, and stir at 220rpm. Then, add 25g of 50wt% gluconic acid aqueous solution, 4g of aminotrimethylenephosphonic acid, 7g of lactic acid, and 2.5g of triisopropanolamine in sequence. After stirring evenly, add 6g of γ-glycidoxypropyltrimethoxysilane dropwise at a rate of 1.2g / min. After the addition is complete, keep the reaction at the temperature for 65min. Then, heat to 62℃ and add a total of 4g of aluminum lactate in four batches, with an interval of 4min between each batch. After the addition is complete, increase the stirring speed to 320rpm and continue the reaction for 45min to obtain the aluminum-containing hybrid precursor.
[0040] Under stirring conditions of 22℃ and 160 rpm, 110 g of an 85 wt% aqueous solution of phosphoric acid was slowly added to the aluminum-containing hybrid precursor, followed by the addition of 12 g of methanesulfonic acid and 21 g of lactic acid. The mixture was stirred for 20 min, and the temperature was controlled using an ice-water bath to ensure that the system temperature did not exceed 28℃. 13.5 g of triisopropanolamine was slowly added dropwise. After the addition was complete, 50 g of an 85 wt% aqueous solution of phosphoric acid was slowly added, and the mixture was stirred for another 20 min. 0.4 g of 5-aminotetrazolium was added, followed by 99.6 g of deionized water. The mixture was stirred for 30 min, and then aged at room temperature for 5 h. The mixture was then filtered through a 0.05 μm polytetrafluoroethylene membrane to obtain agent B.
[0041] First, mix 300g of agent B with 210g of deionized water and stir for 10 minutes for pre-dilution. Then, add 150g of agent A and continue mixing for 6 minutes. Finally, add 90g of deionized water and mix for 10 minutes at 20°C using a static mixer to obtain a two-component copper etching solution.
[0042] Example 4 Add 44g of deionized water to a clean mixing tank, turn on the stirrer, control the temperature at 20℃, slowly add 11g of ethylene glycol monobutyl ether, stir for 10min until the mixture is uniform, then slowly add 145g of 35wt% hydrogen peroxide aqueous solution under light-protected conditions, and continue stirring for 20min to obtain agent A.
[0043] Add 55g of deionized water to the reactor, heat to 38℃, and stir at 180rpm. Then add 15g of 50wt% gluconic acid aqueous solution, 2g of aminotrimethylenephosphonic acid, 4g of lactic acid, and 1.5g of triisopropanolamine in sequence. After stirring evenly, add 3.5g of γ-glycidoxypropyltrimethoxysilane dropwise at a rate of 0.6g / min. After the addition is complete, keep the reaction at the temperature for 50min. Then heat to 52℃ and add a total of 2g of aluminum lactate in two batches, with an interval of 6min between each batch. After the addition is complete, increase the stirring speed to 250rpm and continue the reaction for 30min to obtain the aluminum-containing hybrid precursor.
[0044] 95g of an 85wt% aqueous solution of phosphoric acid was slowly added to the aluminum-containing hybrid precursor under stirring conditions of 20℃ and 150rpm. Then, 9g of methanesulfonic acid and 22g of lactic acid were added, and the mixture was stirred for 20min. The temperature of the system was controlled by an ice-water bath to keep it below 27℃. 10.5g of triisopropanolamine was slowly added dropwise. After the addition was complete, 45g of an 85wt% aqueous solution of phosphoric acid was slowly added, and the mixture was stirred for another 15min. 0.2g of 5-aminotetrazolium was added, followed by 135.3g of deionized water. The mixture was stirred for 25min, and then aged at room temperature for 4h. The mixture was then filtered through a 0.05μm polytetrafluoroethylene filter membrane to obtain agent B.
[0045] First, mix 300g of agent B with 165g of deionized water and stir for 8 minutes for pre-dilution. Then, add 150g of agent A and continue mixing for 5 minutes. Finally, add 135g of deionized water and mix at 20°C using a static mixer for 10 minutes to obtain a two-component copper etching solution.
[0046] Example 5 Add 23g of deionized water to a clean mixing tank, turn on the stirrer, control the temperature at 18℃, slowly add 7g of ethylene glycol monobutyl ether, stir for 10min until the mixture is uniform, then slowly add 170g of 35wt% hydrogen peroxide aqueous solution under light-protected conditions, and continue stirring for 20min to obtain agent A.
[0047] Add 40g of deionized water to the reactor, heat to 50℃, and stir at 220rpm. Then, add 22g of 50wt% gluconic acid aqueous solution, 5g of aminotrimethylenephosphonic acid, 8g of lactic acid, and 3g of triisopropanolamine in sequence. After stirring evenly, add 7g of γ-glycidoxypropyltrimethoxysilane dropwise at a rate of 1.5g / min. After the addition is complete, keep the reaction at the temperature for 70min. Then, heat to 65℃ and add a total of 5g of aluminum lactate in five batches, with an interval of 3min between each batch. After the addition is complete, increase the stirring speed to 320rpm and continue the reaction for 50min to obtain the aluminum-containing hybrid precursor.
[0048] Under stirring conditions of 25℃ and 160 rpm, 120 g of an 85 wt% aqueous solution of phosphoric acid was slowly added to the aluminum-containing hybrid precursor, followed by the addition of 15 g of methanesulfonic acid and 27 g of lactic acid. The mixture was stirred for 20 min, and the temperature was controlled using an ice-water bath to ensure that the system temperature did not exceed 30℃. 17 g of triisopropanolamine was slowly added dropwise. After the addition was complete, 50 g of an 85 wt% aqueous solution of phosphoric acid was slowly added, and the mixture was stirred for another 20 min. 0.6 g of 5-aminotetrazolium was added, followed by 80.4 g of deionized water. The mixture was stirred for 30 min, and then aged at room temperature for 6 h. The mixture was then filtered through a 0.05 μm polytetrafluoroethylene membrane to obtain agent B.
[0049] First, mix 300g of agent B with 225g of deionized water and stir for 10 minutes for pre-dilution. Then, add 150g of agent A and continue mixing for 5 minutes. Finally, add 75g of deionized water and mix at 20°C using a static mixer for 10 minutes to obtain a two-component copper etching solution.
[0050] Example 6 Add 38g of deionized water to a clean mixing tank, turn on the stirrer, control the temperature at 20℃, slowly add 14g of ethylene glycol monobutyl ether, stir for 10min until the mixture is uniform, then slowly add 148g of 35wt% hydrogen peroxide aqueous solution under light-protected conditions, and continue stirring for 20min to obtain agent A.
[0051] Add 65g of deionized water to the reactor, heat to 35℃, and stir at 180rpm. Then, add 12g of 50wt% gluconic acid aqueous solution, 1.5g of aminotrimethylenephosphonic acid, 3g of lactic acid, and 1g of triisopropanolamine in sequence. After stirring evenly, add 2.5g of γ-glycidoxypropyltrimethoxysilane dropwise at a rate of 0.5g / min. After the addition is complete, keep the reaction at the temperature for 40min. Then, heat to 50℃ and add a total of 1.5g of aluminum lactate in two batches, with an interval of 8min between each batch. After the addition is complete, increase the stirring speed to 240rpm and continue the reaction for 25min to obtain the aluminum-containing hybrid precursor.
[0052] Under stirring conditions of 18℃ and 150 rpm, 85 g of 85 wt% phosphoric acid aqueous solution was slowly added to the aluminum-containing hybrid precursor, followed by 6 g of methanesulfonic acid and 17 g of lactic acid. The mixture was stirred for 20 min, and the temperature was controlled using an ice-water bath to ensure that the system temperature did not exceed 25℃. 8 g of triisopropanolamine was slowly added dropwise. After the addition was complete, 60 g of 85 wt% phosphoric acid aqueous solution was slowly added, and the mixture was stirred for another 15 min. 0.15 g of 5-aminotetrazolium was added, followed by 137.35 g of deionized water. The mixture was stirred for 25 min, and then aged at room temperature for 3 h. The mixture was then filtered through a 0.05 μm polytetrafluoroethylene filter membrane to obtain agent B.
[0053] First, mix 300g of agent B with 150g of deionized water and stir for 8 minutes to pre-dilute. Then, add 150g of agent A and continue mixing for 5 minutes. Finally, add 150g of deionized water and mix at 20°C using a static mixer for 10 minutes to obtain a two-component copper etching solution.
[0054] The present invention also includes comparative examples and related experiments.
[0055] Comparative Example 1 The only difference between Comparative Example 1 and Example 1 is that, when preparing Agent B, 5g of γ-glycidoxypropyltrimethoxysilane was added all at once instead of being added dropwise. The other components and preparation methods were the same as in Example 1, and a two-component copper etching solution was prepared.
[0056] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that, in the preparation of Agent B, the independent synthesis step of the "aluminum-containing hybrid precursor" is not carried out. Instead, all the components used to prepare the aluminum-containing hybrid precursor are mixed and reacted together with the subsequent first phosphoric acid aqueous solution, methanesulfonic acid, etc. The other components and preparation methods are the same as in Example 1, and two-component copper etching solutions are prepared.
[0057] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that 5-aminotetrazolium was not added when preparing Agent B. The other components and preparation methods were the same as in Example 1, and a two-component copper etching solution was prepared.
[0058] Performance testing The performance of the two-component copper etching solutions prepared in Examples 1-6 and Comparative Examples 1-3 above was tested. Etching rate: Under the same conditions (temperature: 30℃, etching object: copper foil substrate with a thickness of 35μm), the etching time was measured and the etching rate (μm / min) was calculated. Etching uniformity: The difference in etching depth between different areas (center and edge) of the substrate after etching is measured and expressed as uniformity (minimum etching depth / maximum etching depth × 100%). The higher the value, the better the uniformity. Lateral etching amount: Using photoresist as a mask, the lateral distance (μm) of copper etched below the mask edge is measured by metallographic microscope after etching. Copper surface flatness: After etching, the copper surface morphology is observed using a scanning electron microscope. The evaluation criteria are: excellent (smooth surface, no micro-bumps), good (basically flat surface, with a few micro-bumps), poor (obviously rough surface, with many bumps). Storage stability: Agent A and Agent B were stored separately at 40℃ in a sealed container for 30 days, and the presence of precipitation or stratification was observed. Then they were mixed and an etching test was performed. The change rate of the etching rate was measured as ((initial rate - rate after 30 days) / initial rate × 100%). The smaller the change rate, the better the stability. The test results are summarized in Table 1.
[0059] Table 1
[0060] As shown in Table 1, the two-component copper etching solutions prepared in Examples 1-6 of this invention exhibit excellent performance in terms of etching rate, etching uniformity, lateral etching control, copper surface smoothness, and storage stability. Compared with Example 1, Comparative Example 1 added the silane coupling agent all at once during the preparation of agent B, resulting in intense local reactions and an uneven hybrid precursor structure, ultimately affecting the overall performance of the etching solution. Its etching uniformity and copper surface smoothness were significantly different from Example 1, with increased lateral etching and a marked decrease in storage stability. This indicates that the present invention, by controlling the dropping rate of the silane coupling agent, helps to form a structurally uniform aluminum-containing hybrid precursor, thereby improving the performance of the etching solution. Compared with Example 1, Comparative Example 2 did not pre-synthesize the aluminum-containing hybrid precursor but directly mixed all components. This resulted in aluminum ions not being effectively complexed and hybridized by the organic acid and silane, potentially forming insoluble substances or heterogeneous complexes in subsequent processes, leading to the lowest etching rate, the worst uniformity, the most severe lateral etching, and the worst storage stability. Compared with Example 1, Comparative Example 3 did not contain 5-aminotetrazole. Although its storage stability was better than the first two comparative examples, it was still not as good as Example 1. Furthermore, its etching uniformity and lateral etching amount were significantly worse, indicating that the addition of 5-aminotetrazole played a key role in regulating the reaction uniformity of the etching interface and inhibiting lateral etching.
Claims
1. A method for preparing a two-component copper etching solution, characterized in that, Includes the following steps: Step S1: Mix deionized water, ethylene glycol monobutyl ether, and hydrogen peroxide aqueous solution to obtain agent A; Step S2: Deionized water, gluconic acid aqueous solution, aminotrimethylene phosphonic acid, lactic acid, triisopropanolamine, γ-glycidyl etheroxypropyltrimethoxysilane and aluminum lactate are mixed and reacted to obtain an aluminum-containing hybrid precursor. Step S3: Add aqueous solution of first phosphoric acid, methanesulfonic acid and lactic acid to the aluminum-containing hybrid precursor, followed by the addition of triisopropanolamine, aqueous solution of second phosphoric acid, 5-aminotetrazole and deionized water, and after aging and filtration, obtain agent B; Step S4: Mix agent A, agent B and deionized water to obtain a two-component copper etching solution.
2. The method for preparing a two-component copper etching solution according to claim 1, characterized in that, In step S1, by mass, agent A comprises the following components: 23-44 parts of deionized water, 7-14 parts of ethylene glycol monobutyl ether, and 145-170 parts of hydrogen peroxide aqueous solution.
3. The method for preparing a two-component copper etching solution according to claim 1, characterized in that, The concentration of the hydrogen peroxide aqueous solution is 35 wt%, the concentration of the gluconic acid aqueous solution is 50 wt%, and the concentrations of the first phosphoric acid aqueous solution and the second phosphoric acid aqueous solution are both 85 wt%.
4. The method for preparing a two-component copper etching solution according to claim 1, characterized in that, In step S2, the aluminum-containing hybrid precursor comprises the following components by mass: 40-65 parts of deionized water, 12-25 parts of gluconic acid aqueous solution, 1.5-5 parts of aminotrimethylenephosphonic acid, 3-8 parts of lactic acid, 1-3 parts of triisopropanolamine, 2.5-7 parts of γ-glycidyl etheroxypropyltrimethoxysilane, and 1.5-5 parts of aluminum lactate.
5. The method for preparing a two-component copper etching solution according to claim 1, characterized in that, In step S2, the conditions for the mixing reaction are as follows: the temperature is raised to 35-50℃, and the mixture is stirred at a speed of 180-220 rpm; the dropping rate of the γ-glycidyl etheroxypropyltrimethoxysilane is 0.5-1.5 g / min, and the reaction is maintained at this temperature for 40-70 min after the addition is complete; then the temperature is raised to 50-65℃, and aluminum lactate is added in 2-5 batches with an interval of 3-8 min between each batch; after the aluminum lactate is added, the stirring speed is increased to 240-320 rpm, and the reaction continues for 25-50 min.
6. The method for preparing a two-component copper etching solution according to claim 1, characterized in that, In step S3, when adding the first phosphoric acid aqueous solution, methanesulfonic acid and lactic acid, the temperature is controlled at 18-25℃ and the stirring speed is 150-160 rpm.
7. The method for preparing a two-component copper etching solution according to claim 1, characterized in that, When adding triisopropanolamine, aqueous solution of diphosphate, 5-aminotetrazole and deionized water, use an ice-water bath to control the temperature, keeping the system temperature at 25-30℃.
8. The method for preparing a two-component copper etching solution according to claim 1, characterized in that, In step S3, add 5-aminotetrazole and deionized water, stir for 25-30 minutes, and then mature at room temperature for 3-6 hours.
9. The method for preparing a two-component copper etching solution according to claim 1, characterized in that, In step S4, agent B is first mixed with 150-225 parts of deionized water and stirred for 8-10 minutes for pre-dilution. Then agent A is added and mixed for another 5-6 minutes. Finally, 75-150 parts of deionized water are added and the mixture is stirred in a static mixer at 20-22°C for 10 minutes to obtain a two-component copper etching solution.
10. A two-component copper etching solution, characterized in that, The copper etching solution was prepared using the preparation method of any one of claims 1-9, wherein the B component comprises the following components in parts by weight: 120.4-203.7 parts of deionized water, 12-25 parts of gluconic acid aqueous solution, 1.5-5 parts of aminotrimethylenephosphonic acid, 20-35 parts of lactic acid, 9-20 parts of triisopropanolamine, 2.5-7 parts of γ-glycidyl etheroxypropyltrimethoxysilane, 1.5-5 parts of aluminum lactate, 125-180 parts of phosphoric acid aqueous solution, 6-15 parts of methanesulfonic acid, and 0.15-0.6 parts of 5-aminotetrazole.