Etching liquid composition for suppressing etching blackening and deposition

Abstract

This invention discloses an etching solution composition for inhibiting etching blackening and precipitation, belonging to the field of electronic chemical technology. The etching solution composition, by weight percentage, includes: 10-25% hydrogen peroxide, 3-15% organic acid, 2-10% alkanolamine organic base, 0.01-1.5% resist, 0.1-1% stabilizer, 0.1-3% phenolsulfonic acid, 0.1-3% ethylene oxide polymerized diol, 0.1-3% organic butyl ether, with the balance being deionized water. This invention introduces ethylene oxide polymerized diol and organic butyl ether, forming a synergistic system with alkanolamine organic base and stabilizer. This significantly improves the solubility of the stabilizer and copper ion complex, slows down its aggregation rate, and reduces its adsorption capacity on the substrate surface. Therefore, even at high copper ion concentrations, it can effectively prevent precipitation and substrate blackening, significantly extending the solution life. It is suitable for copper etching processes such as printed circuit boards and lead frames.

Description

Technical Field

[0001] This invention relates to the field of metal etching technology, and more specifically to an etching solution composition that inhibits etching blackening and precipitation. Background Technology

[0002] In fields such as electronics manufacturing and precision machining, copper etching is one of the core processes. Hydrogen peroxide-based copper etching solutions are widely used due to their advantages such as controllable etching rate and environmental friendliness. To ensure the stability of the etching solution, reduce the decomposition rate of hydrogen peroxide, and extend the copper treatment life of the etching solution, existing hydrogen peroxide-based copper etching solutions typically add stabilizers with high coordination stability constants (such as phenylurea compounds), along with components such as organic acids and alkanolamine organic bases, to achieve the complexation of copper ions and control the etching reaction.

[0003] However, existing hydrogen peroxide-based copper etching solutions have significant technical drawbacks: the complexes formed by the stabilizer and copper ions have poor water solubility. As the etching process progresses, the copper concentration in the etching solution continuously increases, and the amount of copper complexes generated exceeds their solubility, easily leading to precipitation. Furthermore, these stabilizer molecules contain many polar bonds, easily forming hydrogen bonds with the surfaces of glass, ceramics, resins, and other substrates, causing blackening of the substrate surface after etching. In addition, under the kinetic conditions of the etching process, copper complexes are prone to agglomeration, forming large particles that clog the pipes and nozzles of the etching equipment, affecting the continuity and stability of the etching process. To solve these blackening and precipitation problems, existing technologies typically reduce the amount of stabilizer added. However, this directly accelerates the decomposition rate of hydrogen peroxide, significantly reducing the copper treatment life of the etching solution, increasing production consumable costs and wastewater treatment costs, and failing to balance the stability, lifespan, and etching effect of the etching solution.

[0004] Therefore, developing an etching solution composition that can effectively solve the problems of blackening and precipitation after etching without reducing the amount of stabilizer has become an urgent technical problem to be solved in this field. Summary of the Invention

[0005] To address the technical problems of existing hydrogen peroxide-based copper etching solutions, such as substrate blackening after etching, easy precipitation in the etching solution, and the difficulty in balancing stabilizer dosage and etching solution lifespan, this invention provides an etching solution composition that inhibits etching blackening and precipitation. Through the synergistic design of each component, while ensuring the normal dosage of stabilizer and maintaining a long etching solution lifespan, the solubility of copper complexes is effectively improved, the aggregation rate of complexes is slowed down, and their adsorption capacity on the substrate surface is reduced, thus fundamentally solving the blackening and precipitation problems while ensuring the rate and accuracy of copper etching.

[0006] To achieve this objective, the present invention employs the following technical solution: An etching solution composition for inhibiting etching blackening and precipitation comprises, by weight percentage: 10-25% hydrogen peroxide, 3-15% organic acid, 2-10% alkanolamine organic base, 0.01-1.5% resist, 0.1-1% stabilizer, 0.1-3% phenolsulfonic acid, 0.1-3% ethylene oxide polymerized diol, 0.1-3% organic butyl ether, with the balance being deionized water.

[0007] The etching solution composition of this application addresses three major technical pain points of existing hydrogen peroxide-based copper etching solutions: First, the complex formed by the stabilizer and copper ions has poor water solubility, leading to precipitation and equipment clogging when copper concentration increases; second, the polar bonds of the stabilizer easily form hydrogen bonds with the substrate, causing substrate blackening after etching; third, existing technologies require reducing the amount of stabilizer to alleviate the above problems, but this accelerates hydrogen peroxide decomposition, significantly shortening the etching solution's lifespan, failing to balance stability and service life. This etching solution, through the synergistic formulation of its components, significantly improves the solubility of the stabilizer-copper ion complex, slows its aggregation rate, and reduces its adsorption capacity on the substrate surface. Therefore, even at high copper ion concentrations, it effectively avoids precipitation and substrate blackening, significantly extending the solution's lifespan. Possible reasons include: hydrogen peroxide provides oxidation power, organic acids and phenolsulfonic acid participate in the reaction as etchants, and the resist regulates the etching rate; alkanolamine organic bases and ethylene oxide polymerized diols synergistically provide ligands, significantly improving the solubility of copper complexes and preventing precipitation; ethylene oxide polymerized diols prevent complex aggregation through steric hindrance, and organic butyl ethers reduce the interfacial tension between the complex and the substrate, inhibiting hydrogen bond adsorption and solving blackening; the stabilizer stabilizes hydrogen peroxide at normal dosage, and its copper complexes are solubilized and dispersed, stabilizing the components in the system, ultimately achieving a comprehensive effect of preventing precipitation, preventing blackening, long lifespan, and stable etching.

[0008] Optionally, the etching solution comprises, by weight percentage, the following components: 9-20% hydrogen peroxide, 4-12% organic acid, 3-8% alkanolamine organic base, 0.05-0.5% resist, 0.2-0.5% stabilizer, 0.1-1% phenolsulfonic acid, 0.5-2% ethylene oxide polymerized diol, 0.5-1.5% organic butyl ether, with the balance being deionized water.

[0009] Optionally, the organic acid includes one or more of malonic acid, malic acid, or citric acid.

[0010] Optionally, the alkanolamine organic base includes one or more of monoethanolamine, diethanolamine, triethanolamine, isopropanolamine, and diisopropanolamine.

[0011] Optionally, the ethylene oxide polymerizable diol includes one or more of diethylene glycol, triethylene glycol, and polyethylene glycol.

[0012] Further optionally, the number average molecular weight of the ethylene oxide polymeric diol is 100-2000.

[0013] Optionally, the organic butyl ether includes one or more of ethylene glycol butyl ether, diethylene glycol butyl ether, and triethylene glycol butyl ether.

[0014] Optionally, the mass ratio of the stabilizer, the alkanolamine organic base, the ethylene oxide polymeric diol, and the organic butyl ether is 1:(9.5~10):(1.25~5):(1.25~5).

[0015] This formulation represents the optimal synergistic ratio of the core functional components, achieving a comprehensive and optimal effect in terms of copper complex solubility, dispersibility, and substrate anti-adsorption. Under this ratio, the ligand supply of the alkanolamine organic base is precisely matched to the copper complexing requirements of the stabilizer. Combined with the auxiliary complexing of the ethylene oxide polymeric diol, the solubility of the stabilizer-copper complex reaches its peak. The synergistic effect of the ethylene oxide polymeric diol and the organic butyl ether in equal proportions maximizes the dual effects of steric hindrance to prevent aggregation and reduced interfacial tension to prevent substrate adsorption, completely resolving the blackening problem. Simultaneously, this formulation precisely controls the amount of alkanolamine organic base, maintaining the acid-base balance of the system, and effectively inhibits hydrogen peroxide decomposition in conjunction with the stabilizer, balancing the stability of the etching solution and the etching rate.

[0016] Optionally, the stabilizer includes one or more of phenylurea, allylurea, 1,3-dimethylurea, thiourea, or phenylacetamide.

[0017] Optionally, the resist includes one or more of 5-aminotetrazole, 3-amino-1,2,3-triazole, 3-amino-1,2,4-triazole, and 4-amino-1,2,3-triazole.

[0018] Beneficial effects 1. The etching solution of the present invention, through the synergistic combination of ethylene oxide polymerized diol, organic butyl ether, stabilizer, and alkanolamine organic base, effectively improves the solubility of copper complex, slows down the aggregation rate of complex, and reduces the adsorption capacity of complex on the substrate surface without reducing the amount of stabilizer. This fundamentally solves the technical problems of substrate blackening and easy precipitation of etching solution after etching.

[0019] 2. By limiting the content range of each component and the mass ratio of the core functional components, this invention achieves comprehensive optimization of etching rate, etching precision, and etching solution stability, thereby improving the copper treatment life of the etching solution and reducing the cost of production consumables and waste liquid treatment.

[0020] 3. The etching solution of the present invention has good compatibility among its components, no side reactions, simple preparation method, easy industrial production, and all raw materials used are conventional industrial grade raw materials, which are readily available and production costs are controllable.

[0021] 4. The etching solution of this invention has a stable etching rate, high etching precision on copper substrates, and no over-etching phenomenon. It is suitable for etching processing of various copper substrates such as printed circuit boards and precision metal parts, with a wide range of applications and good industrial application prospects. Attached Figure Description

[0022] Figure 1 Photograph of the etching solution described in Example 1 after being filtered through 0.2 μm filter paper at a copper concentration of 6000 ppm; Figure 2 Photograph of the etching solution described in Comparative Example 1 after being filtered through 0.2 μm filter paper at a copper concentration of 6000 ppm; Figure 3 Photograph of the etching solution described in Comparative Example 2 after being filtered through 0.2 μm filter paper at a copper concentration of 6000 ppm. Detailed Implementation

[0023] The following detailed description of the claims of the present invention, in conjunction with specific embodiments, is optional and does not constitute any limitation on the present invention. Any limited modifications made by any person within the scope of the claims of the present invention are still within the protection scope of the claims of the present invention.

[0024] Unless otherwise specified, the following examples are all conventional experimental methods and operating procedures in the art.

[0025] Examples 1-5 and Comparative Examples 1-3 An etching solution composition for inhibiting etching blackening and precipitation, the components of which are shown in Table 1 by weight percentage.

[0026] Table 1

[0027] The polyethylene glycol 200 (PEG-200) was purchased from Haian Guoli Chemical Co., Ltd.

[0028] Performance testing Precipitation test: Place each test sample in the etching equipment for copper etching test. When the copper concentration in the etching solution reaches 6kppm, take 100mL of sample and filter it through 0.2μm filter paper. Observe the precipitation residue on the filter paper surface and record the precipitation residue level (no precipitation, trace precipitation, obvious precipitation). Transmittance test: Transmittance was measured at a wavelength of 600 nm using a UV-Vis spectrophotometer (with deionized water as a reference).

[0029] Etching solution life test: Copper powder was continuously added to each test sample, and the maximum copper concentration when obvious precipitation occurred in the etching solution was recorded, which is the copper treatment life of the etching solution. Etching rate test: Standard copper foil was etched using each test sample, with the etching temperature controlled at 35℃. The etching time for a copper foil with a thickness of 30μm was recorded, and the etching rate (μm / min) was calculated.

[0030] The performance test results of each sample are shown in Table 2:

[0031] From Table 2 and Figure 1-3 As can be seen, in Example 1, when the copper concentration reached 6000 ppm, no visible residue was observed after filtration through 0.2 μm filter paper, indicating that the etching solution described in this invention maintains excellent solubility stability even at high copper concentrations. In Comparative Example 1, significant precipitate residue was observed on the filter paper, indicating that a large amount of phenylurea-copper complex precipitated when polyethylene glycol and ethylene glycol butyl ether were lacking. In Comparative Example 2, a small amount of precipitate residue was observed on the filter paper, indicating that insufficient polyethylene glycol and ethylene glycol butyl ether content could not completely suppress precipitation.

Claims

1. An etching solution composition for inhibiting etching blackening and precipitation, characterized in that, By weight percentage, it comprises the following components: 10-25% hydrogen peroxide, 3-15% organic acid, 2-10% alcohol amine organic base, 0.01-1.5% corrosion inhibitor, 0.1-1% stabilizer, 0.1-3% phenol sulfonic acid, 0.1-3% ethylene oxide polymerized diol, 0.1-3% organic butyl ether, and the balance being deionized water.

2. The etching solution composition according to claim 1, characterized in that, The etching solution comprises, by weight percentage, the following components: 9-20% hydrogen peroxide, 4-12% organic acid, 3-8% alkanolamine organic base, 0.05-0.5% resist, 0.2-0.5% stabilizer, 0.1-1% phenolsulfonic acid, 0.5-2% ethylene oxide polymerized diol, 0.5-1.5% organic butyl ether, with the balance being deionized water.

3. The etching solution composition according to claim 1, characterized in that, The organic acid includes one or more of malonic acid, malic acid, or citric acid.

4. The etching solution composition according to claim 1, characterized in that, The alkanolamine organic bases include one or more of monoethanolamine, diethanolamine, triethanolamine, isopropanolamine, and diisopropanolamine.

5. The etching solution composition according to claim 1, characterized in that, The ethylene oxide polymeric diols include diethylene glycol, triethylene glycol, and polyethylene glycol.

6. The etching solution composition according to claim 5, characterized in that, The number average molecular weight of the ethylene oxide polymeric diol is 100-2000.

7. The etching solution composition according to claim 1, characterized in that, The organic butyl ether includes one or more of ethylene glycol butyl ether, diethylene glycol butyl ether, and triethylene glycol butyl ether.

8. The etching solution composition according to claim 1, characterized in that, The mass ratio of the stabilizer, the alcohol amine organic base, the ethylene oxide polymerized diol, and the organic butyl ether is 1:(9.5~10):(1.25~5):(1.25~5).

9. The etching solution composition according to claim 1, characterized in that, The stabilizer includes one or more of phenylurea, allylurea, 1,3-dimethylurea, thiourea, or phenylacetamide.

10. The etching solution composition according to claim 1, characterized in that, The corrosion inhibitor includes one or more of 5-aminotetrazole, 3-amino-1,2,3-triazole, 3-amino-1,2,4-triazole, and 4-amino-1,2,3-triazole.

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