An ultra-fine circuit stripping solution and its preparation method

Abstract

This invention discloses an ultra-fine circuit stripping solution and its preparation method, belonging to the field of printed circuit boards. The ultra-fine circuit stripping solution is characterized by comprising a composite alkali, a corrosion inhibitor, an additive, a surfactant, and a solvent. This invention also provides its preparation method. Compared with existing technologies, the ultra-fine circuit stripping solution prepared by this invention achieves rapid, complete, and selective stripping of high-density fine circuit films by virtue of the efficient bond-breaking ability provided by the composite alkali, the synergistic metal protection of the corrosion inhibitor, the penetration and stripping assistance provided by the surfactant and additive, and the safety and environmental advantages brought by the green solvent system.

Description

Technical Field

[0001] This invention relates to the field of printed circuit board technology, and in particular to an ultra-fine circuit stripping solution and its preparation method. Background Technology

[0002] As electronic components continue to develop towards miniaturization and high-density integration, circuit board manufacturing technology is becoming increasingly sophisticated. Especially in fields such as integrated circuits and high-frequency high-speed communication equipment, the requirements for line width and spacing are becoming increasingly fine, which places higher demands on the precision and stability of the photolithography stripping process.

[0003] Currently, common stripping solutions for printed circuit boards mainly use strongly alkaline systems, such as sodium hydroxide and ammonia, to dissolve or break bonds in the anti-glare or solder resist films. However, these systems generally have the following technical problems:

[0004] (1) Alkaline media can easily cause oxidation or corrosion of copper surfaces, especially under high temperature or long-term processing conditions, which can lead to increased sheet resistance of circuit boards, affecting conductivity and yield.

[0005] (2) Traditional stripping solutions often lack an effective penetration and bond-breaking mechanism for the film layer, making it difficult to completely peel off the anti-light film, resulting in quality problems such as local residual film, pinholes, and even failure of secondary exposure.

[0006] (3) Many existing stripping solutions only add general surfactants or emulsion-type additives, lack directional adsorption functional groups, cannot provide a stable and dense interfacial protective film in a high-alkali environment, and are also difficult to take into account multiple functions such as wetting, dispersion and electrochemical corrosion inhibition.

[0007] (4) Some products have large performance fluctuations under low temperature or high load conditions, which cannot meet the requirements of complex circuit board processes.

[0008] To address the aforementioned issues, an ultra-fine circuit stripping solution is provided that can simultaneously achieve multiple properties such as stripping efficiency, substrate protection, penetration bond breaking, and film formation corrosion inhibition.

[0009] CN113563888A discloses a stripping solution and its preparation method. The stripping solution comprises, by weight, 30%-45% composite alkali, 20%-30% surfactant, 5%-9% corrosion inhibitor, and the remainder is water. The preparation method of this invention is simple, and the resulting stripping solution has good environmental performance, can improve the stripping effect, and can greatly save water and reduce emissions. In addition, it can effectively protect metal from damage during the stripping process. CN109943849A discloses an organic stripping solution comprising the following raw materials by weight percentage: 30-80% organic alkali and 20-70% water, wherein the organic alkali is monoethanolamine; the organic stripping agent is obtained by uniformly dispersing the monoethanolamine in water. This invention's organic stripping solution is particularly suitable for removing dry films from fine circuits, effectively removing film trapping and ensuring the quality of subsequent etching. It boasts a fast stripping rate, 1.5-2 times that of traditional sodium hydroxide stripping, and is especially effective at removing secondary dry films. It does not corrode steel, tin, or gold surfaces, nor does it damage solder resist films such as solder mask. The film fragments are fine, uniform particles, facilitating filtration and preventing nozzle clogging. The solution has a long lifespan, with a maintenance cycle of 7-10 days, improving production efficiency. It produces less waste liquid, is low-cost, and more environmentally friendly. Summary of the Invention

[0010] In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the present invention is to provide an ultra-fine circuit stripping solution that can simultaneously take into account multiple properties such as stripping efficiency, substrate protection, penetration bond breaking and film formation corrosion inhibition.

[0011] To achieve the above objectives, the present invention provides an ultra-fine circuit stripping solution, characterized in that it comprises the following components: composite alkali, corrosion inhibitor, additive, surfactant, and solvent.

[0012] A further preferred embodiment of an ultra-fine circuit stripping solution comprises the following components: 20-40 parts by weight of a composite alkali, 1-6 parts by weight of a corrosion inhibitor, 1-10 parts by weight of an additive, 1-10 parts by weight of a surfactant, and 40-60 parts by weight of a solvent.

[0013] The composite alkali includes inorganic alkali and organic alkali;

[0014] The organic base is at least one of ethanolamine, propylenediamine, tetramethylammonium hydroxide, and ethylenediamine.

[0015] The inorganic base is at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, and strontium hydroxide.

[0016] The corrosion inhibitor is at least one of sulfadiazine and zinc sulfate;

[0017] The surfactant is at least one of octadecyltrimethylammonium bromide, sodium dodecylbenzenesulfonate, fatty alcohol polyoxyethylene ether JEC-E, and isooctanol ether phosphate OEP-70.

[0018] The solvent is a mixture of water and diethylene glycol monobutyl ether;

[0019] The preparation method of the auxiliary agent is as follows:

[0020] (1) Add 0.7-0.9 parts by weight of sodium dodecyl sulfonate to 80-100 parts by weight of water and mix evenly to obtain an aqueous solution of sodium dodecyl sulfonate; add 0.1-0.3 parts by weight of potassium persulfate and 0.01-0.05 parts by weight of sodium bisulfite to 10-20 parts by weight of water and mix evenly to obtain an aqueous solution of potassium persulfate-sodium bisulfite.

[0021] (2) Mix sodium dodecyl sulfonate aqueous solution and potassium persulfate-sodium bisulfite aqueous solution evenly, then add 0.5-2 parts by weight of methacrylic acid, 0.1-1 parts by weight of vinyl silicone oil, 0.1-1 parts by weight of 2-acrylamido-2-methylpropanesulfonic acid, and 0.1-0.5 parts by weight of 4,4-divinyl-2,2-bipyridine and mix evenly. Heat to 60-80℃ and react for 0.5-2 hours. Then add 0.1-1 parts by weight of methacrylic acid, 0.01-0.1 parts by weight of vinyl silicone oil, and 0.01-0.2 parts by weight of 2-acrylamido-2-methylpropanesulfonic acid. Methylpropanesulfonic acid, 0.01-0.1 parts by weight of 4,4-divinyl-2,2-bipyridine, and then add 10-25 parts by weight of sodium dodecyl sulfate aqueous solution (obtained by uniformly mixing 2 parts by weight of sodium dodecyl sulfate and 50 parts by weight of water) and 10-30 parts by weight of potassium persulfate-sodium bisulfite aqueous solution (obtained by uniformly mixing 0.7 parts by weight of potassium persulfate, 0.1 parts by weight of sodium bisulfite and 60 parts by weight of water). React at 70-80℃ for 1-3 hours, cool to 40-60℃ and react for 1-3 hours, cool to 30-40℃, adjust pH to 6-7 to obtain an emulsion;

[0022] (3) Mix 50-100 parts by weight of the above emulsion, 0.5-1 parts by weight of 2-mercaptobenzimidazole and 0.01-0.015 parts by weight of benzoin dimethyl ether evenly, sonicate at 100-200W and 10-20kHz for 10-30 minutes, and irradiate under 365nm ultraviolet light for 0.5-1 hours to obtain the additive.

[0023] The stripping solution provided by this invention employs a composite alkali system composed of organic and inorganic alkalis. These alkaline organic small molecules not only provide a high pH environment to promote the alkaline hydrolysis reaction of the membrane, but also possess good polar solubility and molecular diffusion ability, facilitating the penetration of the stripping solution into the interior of the polymer membrane. Furthermore, some amine molecules possess the ability to complex metal ions, which can alleviate the dissolution rate of the copper surface to a certain extent, thereby reducing the risk of corrosion. The inorganic alkalis used in conjunction, such as sodium hydroxide, potassium hydroxide, sodium carbonate, and strontium hydroxide, provide stronger bond-breaking ability and an ion concentration environment, enabling rapid cleavage of sensitive structures such as ester bonds, amine bonds, or acetal bonds in the membrane. By compounding organic and inorganic alkalis in a reasonable ratio, a unified approach is achieved between rapid swelling and stripping of the membrane and gentle protection of the metal substrate, providing a fundamental guarantee for highly selective stripping of ultra-fine circuits.

[0024] The stripping solution provided by this invention uses water and diethylene glycol monobutyl ether as a mixed solvent. Water, as a polar solvent, possesses good safety and material compatibility, providing the system with basic fluidity and an ionicly active environment. Diethylene glycol monobutyl ether, as a low-volatility organic-loving solvent, significantly enhances the penetration and swelling capacity of hydrophobic membranes, improving stripping efficiency. Furthermore, diethylene glycol monobutyl ether exhibits good dispersibility and solubility stability, effectively preventing the precipitation or sedimentation of reactants or additives, ensuring the long-term stability of the stripping solution. This solvent system possesses good environmental adaptability, operational safety, and stripping uniformity, meeting the dual requirements of modern circuit processing for solvent safety and process stability.

[0025] The surfactant system used in this invention comprises multiple types of compounds, including cationic (octadecyltrimethylammonium bromide), anionic (sodium dodecylbenzenesulfonate), nonionic (fatty alcohol polyoxyethylene ether JEC-E), and a special structure type (isooctanol ether phosphate OEP-70). This compound design combines emulsification, solubilization, wetting, and penetration functions, facilitating the rapid spreading of the stripping solution in high-density wiring structures and effectively preventing droplet accumulation due to excessive surface tension, thereby improving stripping efficiency and detail fidelity. Among these, isooctanol ether phosphate OEP-70, as a phosphorus-containing nonionic surfactant, exhibits excellent penetration and stripping capabilities for polar segments in organic films, achieving gentle and efficient stripping while maintaining the integrity of the material surface.

[0026] A composite corrosion inhibitor system based on sulfadiazine and zinc sulfate is introduced into the stripping solution. Sulfadiazine possesses metal adsorption capacity and interferes with free radical reactions, further stabilizing the interfacial reaction environment and slowing down the electrochemical corrosion process. Furthermore, zinc sulfate provides Zn²⁺, which can combine with OH⁻ released during the stripping process to form an insoluble Zn(OH)₂ deposition layer, thereby forming a physical passivation layer on the metal surface and enhancing the overall corrosion inhibition performance. The synergistic effect of the corrosion inhibitors constructs a metal protective barrier at three levels: chemical adsorption, complexation shielding, and precipitation passivation, achieving effective metal protection in strongly alkaline environments.

[0027] Traditional stripping solutions often suffer from problems such as incomplete membrane penetration, severe metal corrosion, and unclean stripping interfaces. This invention uses methacrylic acid, vinyl silicone oil, 2-acrylamido-2-methylpropanesulfonic acid, and 4,4-divinyl-2,2-bipyridine as raw materials. Under ultraviolet light irradiation with an initiator, a click chemical reaction occurs with 2-mercaptobenzimidazole to prepare an auxiliary agent. The agent is prepared using a combination of surface-initiated polymerization and ultraviolet-excited functional group technology. Structurally, it contains flexible hydrophobic segments and various polar functional groups, exhibiting excellent interfacial wettability and chelating properties. Simultaneously, the complexation ability of the sulfonate group of 2-acrylamido-2-methylpropanesulfonic acid with the metal surface further enhances the adsorption and penetration of the stripping solution at the metal-organic membrane interface. 2-Mercaptobenzimidazole and dimethyl benzoate were added to the obtained emulsion, and a cross-linking reaction was initiated by UV excitation. This further introduced photosensitive functional groups and strongly chelating thiol structures onto the polymer surface, significantly improving the directional enrichment ability of the additives at the release interface and the film softening effect. The sulfonic acid groups (-SO3H), carboxyl groups (-COOH), ether bonds, and long-chain alkyl structures contained in the additives effectively reduced surface tension and improved the wettability and permeability of the stripping solution at the organic film layer and metal interface. Sodium dodecyl sulfonate provided emulsification, forming stable latex particles, which is beneficial for forming a uniform film on the substrate surface. The emulsion polymerization in the aqueous phase forms colloidal latex particles, which easily self-assemble into a uniform and dense polymer film on metal surfaces such as copper under cooling conditions after the reaction. The two N atoms of the imidazole ring in 2-mercaptobenzimidazole provided a π-electron system and lone pair electrons, which easily adsorbed onto the metal surface at multiple points. After adsorption, a dense and ordered molecular film is formed, which shields the migration of corrosive ions (such as OH⁻ and Cl⁻) to the metal surface. The prepared additive itself can form a flexible network structure on the metal surface, and the adsorption stability is enhanced by polymer chain entanglement and van der Waals forces. This structure improves the adhesion of the additive to the interface layer, effectively improving the resistance to leaching. At the same time, it reduces the corrosion rate and delays the aging of the material.

[0028] The present invention also provides a method for preparing an ultra-fine circuit stripping solution.

[0029] A method for preparing an ultra-fine circuit stripping solution includes the following steps: mixing a composite alkali, a corrosion inhibitor, an additive, a surfactant, and a solvent evenly to obtain the ultra-fine circuit stripping solution.

[0030] The beneficial effects of this invention are:

[0031] Compared to existing technologies, this ultra-fine circuit stripping solution achieves rapid, complete, and selective stripping of high-density fine circuit films by leveraging the efficient bond-breaking capability provided by the composite alkali, the synergistic metal protection of the corrosion inhibitor, the penetration and stripping assistance provided by the surfactants and additives, and the safety and environmental advantages brought by the green solvent system. Particularly in stripping applications on easily corroded metal substrates such as copper and aluminum layers, it exhibits extremely low corrosion rates and extremely high circuit fidelity, making it suitable for high-precision fields such as microelectronic packaging and display device manufacturing. This technical solution not only possesses good process adaptability and environmental friendliness but also achieves a good balance between stripping performance and substrate protection, demonstrating superior overall performance compared to existing stripping solutions. Detailed Implementation

[0032] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0033] Description of some of the raw materials used in the embodiments of this invention:

[0034] Vinyl silicone oil, product number: V909861, purchased from Shanghai McLean Biochemical Technology Co., Ltd.

[0035] Aqueous acrylic emulsion, brand name: LA-610A, purchased from Zhaoqing Xinguangli Chemical Industry Co., Ltd.

[0036] Other raw materials not mentioned are all common raw materials. The above content is only for the purpose of illustrating the present invention and should not be construed as a strict limitation of the present invention. Those skilled in the art can directly purchase the same / similar raw materials from the market or prepare them themselves.

[0037] The technical solutions of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Example 1

[0039] An ultra-fine circuit stripping solution comprises the following components: 35 parts by weight of compound alkali, 5 parts by weight of corrosion inhibitor, 8 parts by weight of additive, 8 parts by weight of surfactant, and 60 parts by weight of solvent.

[0040] The composite alkali is composed of ethylenediamine and sodium hydroxide mixed in a mass ratio of 1:1.

[0041] The corrosion inhibitor is composed of sulfadiazine and zinc sulfate in a mass ratio of 2:1.

[0042] The surfactant is composed of fatty alcohol polyoxyethylene ether JEC-E and isooctanol ether phosphate OEP-70 in a mass ratio of 1:3.

[0043] The solvent is a mixture of water and diethylene glycol monobutyl ether in a mass ratio of 4:1.

[0044] The preparation method of the auxiliary agent is as follows:

[0045] (1) Add 0.7 parts by weight of sodium dodecyl sulfonate to 80 parts by weight of water and mix evenly to obtain an aqueous solution of sodium dodecyl sulfonate; add 0.1 parts by weight of potassium persulfate and 0.02 parts by weight of sodium bisulfite to 20 parts by weight of water and mix evenly to obtain an aqueous solution of potassium persulfate-sodium bisulfite.

[0046] (2) Mix sodium dodecyl sulfonate aqueous solution and potassium persulfate-sodium bisulfite aqueous solution evenly, then add 2 parts by weight of methacrylic acid, 1 part by weight of vinyl silicone oil, 1 part by weight of 2-acrylamido-2-methylpropanesulfonic acid, and 0.5 parts by weight of 4,4-divinyl-2,2-bipyridine and mix evenly. Heat to 70°C and react for 0.5 hours. Then add 1 part by weight of methacrylic acid, 0.1 part by weight of vinyl silicone oil, and 0.2 parts by weight of 2-acrylamido-2-methylpropanesulfonic acid. An acid, 0.1 parts by weight of 4,4-divinyl-2,2-bipyridine, and 15 parts by weight of sodium dodecyl sulfate aqueous solution (obtained by uniformly mixing 2 parts by weight of sodium dodecyl sulfate and 50 parts by weight of water) and 20 parts by weight of potassium persulfate-sodium bisulfite aqueous solution (obtained by uniformly mixing 0.7 parts by weight of potassium persulfate, 0.1 parts by weight of sodium bisulfite and 60 parts by weight of water) were added. The mixture was reacted at 75°C for 2 hours, cooled to 50°C for 1 hour, cooled to 40°C, and the pH was adjusted to 6.7 to obtain an emulsion.

[0047] (3) Mix 100 parts by weight of the above emulsion, 1 part by weight of 2-mercaptobenzimidazole and 0.015 parts by weight of benzoin dimethyl ether evenly, sonicate at 200W and 15kHz for 20min, and irradiate under 365nm ultraviolet light for 1h to obtain the additive.

[0048] Example 2

[0049] An ultra-fine circuit stripping solution comprises the following components: 25 parts by weight of compound alkali, 2 parts by weight of corrosion inhibitor, 4 parts by weight of additive, 3 parts by weight of surfactant, and 40 parts by weight of solvent.

[0050] The composite alkali is composed of ethylenediamine and sodium hydroxide mixed in a mass ratio of 1:1.

[0051] The corrosion inhibitor is composed of sulfadiazine and zinc sulfate in a mass ratio of 2:1.

[0052] The surfactant is composed of fatty alcohol polyoxyethylene ether JEC-E and isooctanol ether phosphate OEP-70 in a mass ratio of 1:3.

[0053] The solvent is a mixture of water and diethylene glycol monobutyl ether in a mass ratio of 4:1.

[0054] The preparation method of the auxiliary agent is as follows:

[0055] (1) Add 0.7 parts by weight of sodium dodecyl sulfonate to 80 parts by weight of water and mix evenly to obtain an aqueous solution of sodium dodecyl sulfonate; add 0.1 parts by weight of potassium persulfate and 0.02 parts by weight of sodium bisulfite to 20 parts by weight of water and mix evenly to obtain an aqueous solution of potassium persulfate-sodium bisulfite.

[0056] (2) Mix sodium dodecyl sulfonate aqueous solution and potassium persulfate-sodium bisulfite aqueous solution evenly, then add 2 parts by weight of methacrylic acid, 1 part by weight of vinyl silicone oil, 1 part by weight of 2-acrylamido-2-methylpropanesulfonic acid, and 0.5 parts by weight of 4,4-divinyl-2,2-bipyridine and mix evenly. Heat to 70°C and react for 0.5 hours. Then add 1 part by weight of methacrylic acid, 0.1 part by weight of vinyl silicone oil, and 0.2 parts by weight of 2-acrylamido-2-methylpropanesulfonic acid. An acid, 0.1 parts by weight of 4,4-divinyl-2,2-bipyridine, and 15 parts by weight of sodium dodecyl sulfate aqueous solution (obtained by uniformly mixing 2 parts by weight of sodium dodecyl sulfate and 50 parts by weight of water) and 20 parts by weight of potassium persulfate-sodium bisulfite aqueous solution (obtained by uniformly mixing 0.7 parts by weight of potassium persulfate, 0.1 parts by weight of sodium bisulfite and 60 parts by weight of water) were added. The mixture was reacted at 75°C for 2 hours, cooled to 50°C for 1 hour, cooled to 40°C, and the pH was adjusted to 6.7 to obtain an emulsion.

[0057] (3) Mix 100 parts by weight of the above emulsion, 1 part by weight of 2-mercaptobenzimidazole and 0.015 parts by weight of benzoin dimethyl ether evenly, sonicate at 200W and 15kHz for 20min, and irradiate under 365nm ultraviolet light for 1h to obtain the additive.

[0058] Example 3

[0059] An ultra-fine circuit stripping solution comprises the following components: 40 parts by weight of compound alkali, 6 parts by weight of corrosion inhibitor, 10 parts by weight of additive, 8 parts by weight of surfactant, and 60 parts by weight of solvent.

[0060] The composite alkali is composed of ethylenediamine and sodium hydroxide mixed in a mass ratio of 1:1.

[0061] The corrosion inhibitor is composed of sulfadiazine and zinc sulfate in a mass ratio of 2:1.

[0062] The surfactant is composed of fatty alcohol polyoxyethylene ether JEC-E and isooctanol ether phosphate OEP-70 in a mass ratio of 1:3.

[0063] The solvent is a mixture of water and diethylene glycol monobutyl ether in a mass ratio of 4:1.

[0064] The preparation method of the auxiliary agent is as follows:

[0065] (1) Add 0.7 parts by weight of sodium dodecyl sulfonate to 80 parts by weight of water and mix evenly to obtain an aqueous solution of sodium dodecyl sulfonate; add 0.1 parts by weight of potassium persulfate and 0.02 parts by weight of sodium bisulfite to 20 parts by weight of water and mix evenly to obtain an aqueous solution of potassium persulfate-sodium bisulfite.

[0066] (2) Mix sodium dodecyl sulfonate aqueous solution and potassium persulfate-sodium bisulfite aqueous solution evenly, then add 2 parts by weight of methacrylic acid, 1 part by weight of vinyl silicone oil, 1 part by weight of 2-acrylamido-2-methylpropanesulfonic acid, and 0.5 parts by weight of 4,4-divinyl-2,2-bipyridine and mix evenly. Heat to 70°C and react for 0.5 hours. Then add 1 part by weight of methacrylic acid, 0.1 part by weight of vinyl silicone oil, and 0.2 parts by weight of 2-acrylamido-2-methylpropanesulfonic acid. An acid, 0.1 parts by weight of 4,4-divinyl-2,2-bipyridine, and 15 parts by weight of sodium dodecyl sulfate aqueous solution (obtained by uniformly mixing 2 parts by weight of sodium dodecyl sulfate and 50 parts by weight of water) and 20 parts by weight of potassium persulfate-sodium bisulfite aqueous solution (obtained by uniformly mixing 0.7 parts by weight of potassium persulfate, 0.1 parts by weight of sodium bisulfite and 60 parts by weight of water) were added. The mixture was reacted at 75°C for 2 hours, cooled to 50°C for 1 hour, cooled to 40°C, and the pH was adjusted to 6.7 to obtain an emulsion.

[0067] (3) Mix 100 parts by weight of the above emulsion, 1 part by weight of 2-mercaptobenzimidazole and 0.015 parts by weight of benzoin dimethyl ether evenly, sonicate at 200W and 15kHz for 20min, and irradiate under 365nm ultraviolet light for 1h to obtain the additive.

[0068] Example 4

[0069] An ultra-fine circuit stripping solution comprises the following components: 35 parts by weight of compound alkali, 5 parts by weight of corrosion inhibitor, 8 parts by weight of additive, 8 parts by weight of surfactant, and 60 parts by weight of solvent.

[0070] The composite alkali is composed of ethylenediamine and sodium hydroxide mixed in a mass ratio of 1:1.

[0071] The corrosion inhibitor is composed of sulfadiazine and zinc sulfate in a mass ratio of 2:1.

[0072] The surfactant is composed of fatty alcohol polyoxyethylene ether JEC-E and isooctanol ether phosphate OEP-70 in a mass ratio of 1:3.

[0073] The solvent is a mixture of water and diethylene glycol monobutyl ether in a mass ratio of 4:1.

[0074] The additive is an aqueous acrylic emulsion.

[0075] Example 5

[0076] An ultra-fine circuit stripping solution comprises the following components: 35 parts by weight of compound alkali, 5 parts by weight of corrosion inhibitor, 8 parts by weight of additive, 8 parts by weight of surfactant, and 60 parts by weight of solvent.

[0077] The composite alkali is composed of ethylenediamine and sodium hydroxide mixed in a mass ratio of 1:1.

[0078] The corrosion inhibitor is composed of sulfadiazine and zinc sulfate in a mass ratio of 2:1.

[0079] The surfactant is composed of fatty alcohol polyoxyethylene ether JEC-E and isooctanol ether phosphate OEP-70 in a mass ratio of 1:3.

[0080] The solvent is a mixture of water and diethylene glycol monobutyl ether in a mass ratio of 4:1.

[0081] The preparation method of the auxiliary agent is as follows:

[0082] (1) Add 0.7 parts by weight of sodium dodecyl sulfonate to 80 parts by weight of water and mix evenly to obtain an aqueous solution of sodium dodecyl sulfonate; add 0.1 parts by weight of potassium persulfate and 0.02 parts by weight of sodium bisulfite to 20 parts by weight of water and mix evenly to obtain an aqueous solution of potassium persulfate-sodium bisulfite.

[0083] (2) Mix sodium dodecyl sulfonate aqueous solution and potassium persulfate-sodium bisulfite aqueous solution evenly, then add 2 parts by weight of methacrylic acid, 1 part by weight of vinyl silicone oil, 1 part by weight of 2-acrylamido-2-methylpropanesulfonic acid, and 0.5 parts by weight of 4,4-divinyl-2,2-bipyridine and mix evenly. Heat to 70°C and react for 0.5 hours. Then add 1 part by weight of methacrylic acid, 0.1 part by weight of vinyl silicone oil, and 0.2 parts by weight of 2-acrylamido-2-methylpropanesulfonic acid. An acid, 0.1 parts by weight of 4,4-divinyl-2,2-bipyridine, and 15 parts by weight of sodium dodecyl sulfate aqueous solution (obtained by uniformly mixing 2 parts by weight of sodium dodecyl sulfate and 50 parts by weight of water) and 20 parts by weight of potassium persulfate-sodium bisulfite aqueous solution (obtained by uniformly mixing 0.7 parts by weight of potassium persulfate, 0.1 parts by weight of sodium bisulfite and 60 parts by weight of water) were added. The mixture was reacted at 75°C for 2 hours, cooled to 50°C for 1 hour, cooled to 40°C, and the pH was adjusted to 6.7 to obtain the auxiliary agent.

[0084] Example 6

[0085] An ultra-fine circuit stripping solution comprises the following components: 35 parts by weight of compound alkali, 5 parts by weight of corrosion inhibitor, 8 parts by weight of surfactant, and 60 parts by weight of solvent.

[0086] The composite alkali is composed of ethylenediamine and sodium hydroxide mixed in a mass ratio of 1:1.

[0087] The corrosion inhibitor is composed of sulfadiazine and zinc sulfate in a mass ratio of 2:1.

[0088] The surfactant is composed of fatty alcohol polyoxyethylene ether JEC-E and isooctanol ether phosphate OEP-70 in a mass ratio of 1:3.

[0089] The solvent is a mixture of water and diethylene glycol monobutyl ether in a mass ratio of 4:1.

[0090] Example 7

[0091] An ultra-fine circuit stripping solution comprises the following components: 35 parts by weight of compound alkali, 5 parts by weight of corrosion inhibitor, 8 parts by weight of additive, 8 parts by weight of surfactant, and 60 parts by weight of solvent.

[0092] The composite alkali is composed of ethylenediamine and sodium hydroxide mixed in a mass ratio of 1:1.

[0093] The corrosion inhibitor is composed of sulfadiazine and zinc sulfate in a mass ratio of 2:1.

[0094] The surfactant is composed of fatty alcohol polyoxyethylene ether JEC-E and isooctanol ether phosphate OEP-70 in a mass ratio of 1:3.

[0095] The solvent is a mixture of water and diethylene glycol monobutyl ether in a mass ratio of 4:1.

[0096] The additive is vinyl silicone oil.

[0097] Comparative Example 1

[0098] It is basically the same as Example 5, except that vinyl silicone oil is not added in the preparation method of the additive.

[0099] Comparative Example 2

[0100] It is basically the same as Example 5, except that 2-acrylamido-2-methylpropanesulfonic acid is not added in the preparation method of the additive.

[0101] Comparative Example 3

[0102] It is basically the same as Example 5, except that 4,4-divinyl-2,2-bipyridine is not added in the preparation method of the additive.

[0103] Comparative Example 4

[0104] It is basically the same as Example 5, except that vinyl silicone oil and 2-acrylamido-2-methylpropanesulfonic acid are not added in the preparation method of the additive.

[0105] Comparative Example 5

[0106] The method is basically the same as in Example 5, except that 2-acrylamido-2-methylpropanesulfonic acid and 4,4-divinyl-2,2-bipyridine are not added in the preparation method of the additive.

[0107] Comparative Example 6

[0108] The method is basically the same as in Example 5, except that vinyl silicone oil and 4,4-divinyl-2,2-bipyridine are not added in the preparation method of the additive.

[0109] Comparative Example 7

[0110] The method is basically the same as Example 5, except that vinyl silicone oil, 2-acrylamido-2-methylpropanesulfonic acid, and 4,4-divinyl-2,2-bipyridine are not added in the preparation method of the additive.

[0111] Test Example 1

[0112] The circuit board was prepared using the mSAP process in the following order: copper substrate - film exposure - development - copper electroplating - washing and drying. The dry film thickness was 30μm, and the copper electroplating thickness was 20μm. The test board was then cut into 10cm×8cm test pieces with a line width / dry film width of 20μm / 20μm to obtain the circuit board.

[0113] The stripping solutions prepared in each embodiment were used to strip the film from the circuit board described above, wherein the spraying pressure of the stripping solution was 1.6 kg / cm². 2 The temperature of the stripping solution is 50℃, and the stripping time is 3 minutes. After stripping, use a microscope or high-magnification loupe to check the surface of the substrate to confirm whether there is any dry film or other material residue.

[0114] Table 1

[0115]

[0116] Test Example 2

[0117] The sheet resistance of the circuit board in Test Example 1 was tested before and after the treatment. The change rate of sheet resistance was observed. The change rate of sheet resistance = (sheet resistance after treatment - sheet resistance before treatment) / sheet resistance before treatment * 100%. Five sets of tests were conducted for each group, and the average value was taken.

[0118] Table 2

[0119]

[0120] As shown in Table 2, the stripping solution prepared in this invention exhibits excellent metal protection performance, indicating that the additives in these formulations have complete structures, forming a dense, stable, and highly adsorbent interfacial protective layer. A composite corrosion inhibitor system based on sulfadiazine and zinc sulfate is introduced into the stripping solution. Sulfadiazine is a nitrogen-containing aromatic heterocyclic compound that combines metal adsorption capacity with interference against free radical reactions, further stabilizing the interfacial reaction environment and slowing down the electrochemical corrosion process. In addition, zinc sulfate provides Zn... 2+ It can react with the OH released during the peeling process. - The combination generates an insoluble Zn(OH)2 deposition layer, thereby forming a physical passivation layer on the metal surface and enhancing the overall corrosion inhibition performance. At the same time, it interacts with 2-mercaptobenzimidazole in the additive to construct a metal protection barrier from three levels: chemical adsorption, complexation shielding and precipitation passivation, thereby achieving effective metal protection in a strongly alkaline environment.

[0121] This invention uses methacrylic acid, vinyl silicone oil, 2-acrylamido-2-methylpropanesulfonic acid, and 4,4-divinyl-2,2-bipyridine as raw materials. Under ultraviolet light irradiation with an initiator, a click chemical reaction occurs with 2-mercaptobenzimidazole to prepare an auxiliary agent. The agent is prepared using a combination of surface-active initiation polymerization and ultraviolet-excited functional group technology. Structurally, it contains flexible hydrophobic segments and various polar functional groups, exhibiting good interfacial wettability and chelating properties. Simultaneously, the complexation ability of the sulfonate group in 2-acrylamido-2-methylpropanesulfonic acid with the metal surface further enhances the adsorption and penetration of the stripping solution at the metal-organic membrane interface. Adding 2-mercaptobenzimidazole and dimethyl benzoate to the resulting emulsion and initiating a crosslinking reaction using ultraviolet light further introduces photosensitive functional groups and strongly chelating thiol structures onto the polymer surface, significantly improving the directional enrichment ability and film softening effect of the auxiliary agent at the stripping interface. The sulfonic acid groups (-SO3H), carboxyl groups (-COOH), ether bonds, and long-chain alkyl structures contained in the additives effectively reduce surface tension and improve the wettability and permeability of the stripping solution at the organic film layer and metal interface. Sodium dodecyl sulfonate provides emulsification, forming stable latex particles, which is beneficial for forming a uniform film on the substrate surface. Emulsion polymerization forms colloidal latex particles in the aqueous phase, which readily self-assemble into a uniform and dense polymer film on metal surfaces such as copper under cooling conditions after the reaction. The two nitrogen atoms in the imidazole ring of 2-mercaptobenzimidazole provide a π-electron system and lone pairs of electrons, which easily adsorb at multiple points on the metal surface. After adsorption, a dense and ordered molecular film is formed, shielding against corrosive ions (such as OH-). - Cl - The additives can migrate to the metal surface; the prepared additives can form a flexible network structure on the metal surface, and enhance adsorption stability through polymer chain entanglement and van der Waals forces; this structure improves the adhesion of the additives to the interface layer, effectively improving the resistance to leaching; at the same time, it reduces the corrosion rate and delays the aging of the material.

[0122] Test Example 3

[0123] The circuit boards in Test Example 1 before and after the film peeling process were weighed, and their weight loss rate was calculated.

[0124] Table 3

[0125]

[0126] The ultra-fine circuit stripping solution provided by this invention achieves rapid, complete, and selective stripping of high-density fine circuit films by leveraging the efficient bond-breaking ability of the composite alkali, the synergistic metal protection of the corrosion inhibitor, the penetration and stripping assistance provided by the surfactant and additives, and the safety and environmental advantages brought by the green solvent system. Especially in stripping applications on easily corroded metal substrates such as copper and aluminum layers, it exhibits extremely low corrosion rates and extremely high circuit fidelity, making it suitable for high-precision fields such as microelectronic packaging and display device manufacturing. This technical solution not only possesses good process adaptability and environmental friendliness, but also achieves a good balance between stripping performance and substrate protection, demonstrating comprehensive performance superior to existing stripping solutions.

[0127] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A stripping solution for ultra-fine circuit films, characterized in that: It includes the following components: 20-40 parts by weight of compound alkali, 1-6 parts by weight of corrosion inhibitor, 1-10 parts by weight of additive, 1-10 parts by weight of surfactant, and 40-60 parts by weight of solvent. The preparation method of the auxiliary agent is as follows: (1) Add 0.7-0.9 parts by weight of sodium dodecyl sulfonate to 80-100 parts by weight of water and mix evenly to obtain an aqueous solution of sodium dodecyl sulfonate; add 0.1-0.3 parts by weight of potassium persulfate and 0.01-0.05 parts by weight of sodium bisulfite to 10-20 parts by weight of water and mix evenly to obtain potassium persulfate. Sodium bisulfite aqueous solution; (2) Mix sodium dodecyl sulfonate aqueous solution and potassium persulfate-sodium bisulfite aqueous solution evenly, then add 0.5-2 parts by weight of methacrylic acid, 0.1-1 parts by weight of vinyl silicone oil, 0.1-1 parts by weight of 2-acrylamido-2-methylpropanesulfonic acid, and 0.1-0.5 parts by weight of 4,4-divinyl-2,2-bipyridine and mix evenly. Heat to 60-80℃ and react for 0.5-2 hours. Then add 0.1-1 parts by weight of methacrylic acid, 0.01-0.1 parts by weight of vinyl silicone oil, 0.01-0.2 parts by weight of 2-acrylamido-2-methylpropanesulfonic acid, and 0.01-0.1 parts by weight of 4,4-divinyl- 2,2-Bipyridine is added, followed by 10-25 parts by weight of sodium dodecyl sulfate aqueous solution and 10-30 parts by weight of potassium persulfate-sodium bisulfite aqueous solution. The mixture is reacted at 70-80℃ for 1-3 hours, then cooled to 40-60℃ for 1-3 hours, then cooled to 30-40℃, and the pH is adjusted to 6-7 to obtain an emulsion. The 10-30 parts by weight of potassium persulfate-sodium bisulfite aqueous solution is prepared by mixing 0.7 parts by weight of potassium persulfate, 0.1 parts by weight of sodium bisulfite, and 60 parts by weight of water evenly. The 10-25 parts by weight of sodium dodecyl sulfate aqueous solution is prepared by mixing 2 parts by weight of sodium dodecyl sulfate and 50 parts by weight of water evenly. (3) Mix 50-100 parts by weight of the above emulsion, 0.5-1 parts by weight of 2-mercaptobenzimidazole, and 0.01-0.015 parts by weight of benzoin dimethyl ether evenly, sonicate at 100-200W and 10-20kHz for 10-30 minutes, and irradiate under 365nm ultraviolet light for 0.5-1 hours to obtain the auxiliary agent; The composite alkali is composed of ethylenediamine and sodium hydroxide mixed in a mass ratio of 1:

1. The corrosion inhibitor is composed of sulfadiazine and zinc sulfate in a mass ratio of 2:

1. The surfactant is composed of fatty alcohol polyoxyethylene ether JEC-E and isooctyl ether phosphate OEP-70 in a mass ratio of 1:

3. The solvent is a mixture of water and diethylene glycol monobutyl ether in a mass ratio of 4:

1.

2. A method for preparing the ultra-fine circuit stripping solution as described in claim 1, characterized in that: The ultra-fine circuit stripping solution is obtained by mixing the composite alkali, corrosion inhibitor, additive, surfactant and solvent evenly.

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