A dual-component copper-molybdenum-titanium etching solution and its preparation method

Abstract

This invention relates to the field of etching solution technology, particularly to the field of IPC C23F, and more specifically, to a two-component copper-molybdenum-titanium etching solution and its preparation method. It comprises a main agent and an auxiliary agent. By weight, the main agent consists of: 8-15 parts oxidant, 4-13 parts first organic acid, 1-3 parts first inorganic acid, 1-3 parts first organic base, 1-4 parts first surfactant, 0.05-0.5 parts first fluorinated compound, 0.01-1 parts first corrosion inhibitor, and 60-80 parts water. The auxiliary agent consists of: 10-60 parts second organic acid, 2-10 parts second inorganic acid, 1-5 parts second organic base, 0.05-0.5 parts second fluorinated compound, 1-5 parts second surfactant, 0.5-2 parts second corrosion inhibitor, and 50-80 parts water. This invention solves problems such as large etching rate fluctuations, chamfering, vertical angles, precipitation, and crystallization during the etching process.

Description

Technical Field

[0001] This invention relates to the field of etching solution technology, particularly to the field of IPC C23F, and more specifically, to a two-component copper-molybdenum-titanium etching solution and its preparation method. Background Technology

[0002] With the development of display technology, especially towards larger and higher resolution displays, traditional metal conductors experience increased resistance as the wiring lengthens, leading to signal delays and degraded display quality. Therefore, research began on using metal wiring with lower resistance, specifically copper-based processes. Because the composition of metal films varies, and the proportions of each film are different, the etching solution is a specially formulated chemical. Existing etching agents mostly contain citric acid, nitric acid, phosphoric acid, hydroxyethyl sulfonic acid, and iminodiacetic acid as the main acids; using any one of these materials alone can result in poor etching.

[0003] CN109136931A discloses a high-efficiency copper-molybdenum etching solution, comprising: hydrogen peroxide accounting for 7-15% of the total mass of the etching solution, a regulator accounting for 2-7% of the total mass of the etching solution, a stabilizer accounting for 1-3% of the total mass of the etching solution, an organic acid accounting for 3-10% of the total mass of the etching solution, an inhibitor accounting for 0.001-1% of the total mass of the etching solution, and a pH adjuster accounting for 1-10% of the total mass of the etching solution, with the balance being deionized water; this invention enhances the oxidation ability of copper-molybdenum metal films, further accelerates the etching reaction rate, and further improves the etching quality, but a single type of organic acid cannot simultaneously solve problems such as large fluctuations in etching rate, chamfering, vertical angles, precipitation, and crystallization. Summary of the Invention

[0004] The first aspect of this invention provides a two-component copper-molybdenum-titanium etching solution, comprising a main agent and an auxiliary agent. By weight, the main agent comprises: 8-15 parts of an oxidant, 4-13 parts of a first organic acid, 1-3 parts of a first inorganic acid, 1-3 parts of a first organic base, 1-4 parts of a first surfactant, 0.05-0.5 parts of a first fluorinated compound, 0.01-1 parts of a first corrosion inhibitor, and 60-80 parts of water. The auxiliary agent comprises: 10-60 parts of a second organic acid, 2-10 parts of a second inorganic acid, 1-5 parts of a second organic base, 0.05-0.5 parts of a second fluorinated compound, 1-5 parts of a second surfactant, 0.5-2 parts of a second corrosion inhibitor, and 50-80 parts of water.

[0005] The oxidant includes one of hydrogen peroxide and persulfate.

[0006] The first organic acid and the second organic acid are both selected from at least one of citric acid, iminodiacetic acid, glycolic acid, lactic acid, hydroxyethyl sulfonic acid, and phenol sulfonic acid.

[0007] The first surfactant and the second surfactant are both selected from at least one of ethylene glycol, glycerol, thiol, ethylene glycol butyl ether, glycerol ethyl ether, and glycerol methyl ether.

[0008] Preferably, both the first organic acid and the second organic acid are selected from at least one of lactic acid, citric acid, and hydroxyethyl sulfonic acid.

[0009] The first inorganic acid and the second inorganic acid are both selected from at least one of hydrochloric acid, nitric acid, phosphoric acid, and pyrophosphate.

[0010] The first organic base and the second organic base are both selected from at least one of phenylenediamine, dimethylaminopropylamine, isopropanolamine, diethanolamine, and triisopropanolamine.

[0011] The first corrosion inhibitor and the second corrosion inhibitor are both selected from at least one of methylazole, aminoazole, and pantothenic acid.

[0012] The first fluorinated compound and the second fluorinated compound are both selected from at least one of hydrofluoric acid, ammonium fluoride, and ammonium bifluoride.

[0013] Preferably, both the first corrosion inhibitor and the second corrosion inhibitor are selected from at least one of pyridine-3-carboxylic acid, 5-aminotetrazole, 5-methyltetrazole, 4-amino-1,2,4-triazole, and 3-amino-1,2,4-triazole.

[0014] More preferably, both the first corrosion inhibitor and the second corrosion inhibitor comprise pyridine-3-carboxylic acid and 4-amino-1,2,4-triazole.

[0015] More preferably, the weight ratio of pyridine-3-carboxylic acid and 4-amino-1,2,4-triazole in the main agent is (2-5):1.

[0016] The weight ratio of the oxidant to the first fluorinated compound is (8-15):0.1.

[0017] Preferably, the weight ratio of the oxidant to the first fluorinated compound is (8-11):0.1.

[0018] Preferably, the main agent includes lactic acid, hydrofluoric acid, nitric acid and pyridine-3-carboxylic acid, and the weight ratio of lactic acid, hydrofluoric acid, nitric acid and pyridine-3-carboxylic acid is 12:(0.05-0.3):(1-5):(0.1-1).

[0019] Preferably, the main agent comprises glycerol methyl ether and dimethyl ethanolamine, wherein the weight ratio of glycerol methyl ether to dimethyl ethanolamine is 1:(2-5).

[0020] Preferably, the main agent includes lactic acid, hydrofluoric acid, nitric acid and pyridine-3-carboxylic acid, and the weight ratio of lactic acid, hydrofluoric acid, nitric acid and pyridine-3-carboxylic acid is 12:(0.05-0.2):(2-4):(0.1-0.6).

[0021] This application research found that by adding a fluorine compound to the main agent, and the weight ratio of the oxidant to the first fluorine-containing compound being (8-11):0.1, the etching rate can be slowed down, resulting in a CD-loss <0.9μm. However, when fluorine-containing etching solutions are applied to titanium metal, precipitates or crystals often appear, especially after 6000ppm, when the amount of precipitates and exudates increases significantly, clogging the filter element and preventing mass production. Further research in this application found that the main agent includes lactic acid, hydrofluoric acid, nitric acid, and pyridine-3-carboxylic acid, and the weight ratio of lactic acid, hydrofluoric acid, nitric acid, and pyridine-3-carboxylic acid is 12:(0.05-0.2):(2-4):(0.1-0.6), which can solve problems such as large etching rate fluctuations, chamfers, vertical angles, precipitation, and crystallization, and obtain excellent etching morphology.

[0022] More preferably, the main agent comprises glycerol methyl ether and dimethyl ethanolamine, wherein the weight ratio of glycerol methyl ether to dimethyl ethanolamine is 1:(2-4).

[0023] Preferably, the amount of the second organic acid added to the excipient is 45-50 wt%.

[0024] The weight ratio of the second organic acid to the second inorganic acid is 50:(1-5).

[0025] Preferably, the weight ratio of the second organic acid to the second inorganic acid is 50:(1-3).

[0026] The weight ratio of the second organic base, the second fluorinated compound, the second surfactant, and the second corrosion inhibitor is 5:(0.2-1):(1-4):(1-3).

[0027] Preferably, the excipients include the following components: lactic acid, hydrofluoric acid, nitric acid, pyridine-3-carboxylic acid, glycerol methyl ether, and dimethyl ethanolamine.

[0028] The second aspect of the present invention provides a method for preparing a two-component copper-molybdenum-titanium etching solution, comprising the following steps: mixing the components of the main agent evenly and mixing the components of the auxiliary agent evenly, thereby obtaining the solution.

[0029] Beneficial effects

[0030] 1. By adding a fluorinated compound to the main agent, with the weight ratio of the oxidant to the first fluorinated compound being (8-11):

[0031] A value of 0.1 can slow down the etching rate, resulting in a CD-loss of <0.9μm.

[0032] 2. The main agent includes lactic acid, hydrofluoric acid, nitric acid and pyridine-3-carboxylic acid, and the weight ratio of lactic acid, hydrofluoric acid, nitric acid and pyridine-3-carboxylic acid is 12:(0.05-0.2):(2-4):(0.1-0.6), which can solve problems such as large fluctuations in etching rate, chamfering, vertical angles, precipitation and crystallization.

[0033] 3. The dual-agent etching solution of this application has a lifespan of 14,000 ppm, which greatly reduces the probability of scratches on the crystal glass substrate.

[0034] 4. The initial concentration of oxidant is moderate (8%-14%), resulting in low safety risks.

[0035] 5. No problems such as chamfering or metal interface cracks occur during the etching process of the dual-agent etching solution of this application.

[0036] 6. The two-component etching solution of this application exhibits molybdenum-titanium tailing during the etching process (molybdenum residue lower limit < 0.6 μm, tail 0.10-0.2 μm), with good morphology. No precipitation occurs at the end of the etching process, and the etching characteristics are stable (slope angle).

[0037] (60-70°). Attached Figure Description

[0038] Figure 1 The image shows the morphology of copper-molybdenum-titanium after etching in Example 5.

[0039] Figure 2 yes Figure 1 The optimal values ​​for the measured SEM results are CD-loss = 0.75-0.85um and Taper = 60-70°.

[0040] Figure 3 It is indicated that the optimal lower limit of molybdenum-titanium residue after etching in Example 5 is CD-loss < 0.6 μm.

[0041] Figure 4 The image shows the morphology of the trailing edge after etching in Example 5. Optimal values ​​are 0.1µm < trailing edge CD-loss < 0.2µm. Detailed Implementation

[0042] Examples 1-8

[0043] A two-component copper-molybdenum-titanium etching solution includes a main agent and an auxiliary agent, and the formulation is shown in Table 1 by weight:

[0044] Table 1

[0045]

[0046]

[0047] A method for preparing a two-component copper-molybdenum-titanium etching solution includes the following steps: mixing the components of the main agent evenly and mixing the components of the auxiliary agent evenly to obtain the solution.

[0048] Performance testing methods and data

[0049] Etching composition and specific application method: First use the main etchant. For every 1000ppm increase in copper ions, add 1wt% of the main agent dosage of the auxiliary agent to the system. The etching test results are shown in Table 2.

[0050] Figure 1 The image shows the morphology of copper-molybdenum-titanium after etching in Example 5.

[0051] Figure 2 yes Figure 1 The optimal values ​​for the measured SEM results are CD-loss = 0.75-0.85 μm and Taper = 60-70°.

[0052] Figure 3 It is indicated that the optimal lower limit of molybdenum-titanium residue after etching in Example 5 is CD-loss < 0.6 μm.

[0053] Figure 4 The image shows the morphology of the trailing edge after etching in Example 5. Optimal values ​​are 0.1µm < trailing edge CD-loss < 0.2µm.

[0054] Table 2

[0055]

Claims

1. A two-component copper-molybdenum-titanium etching solution, characterized in that, The product comprises a main agent and excipients. By weight, the main agent consists of: 11 parts hydrogen peroxide, 12 parts lactic acid, 3 parts nitric acid, 0.1 parts phosphoric acid, 2.9 parts dimethyl ethanolamine, 0.1 parts hydrofluoric acid, 1 part glycerol methyl ether, 0.3 parts pyridine-3-carboxylic acid, 0.1 parts 4-amino-1,2,4-triazole, and 69.5 parts water. The excipients consist of: 50 parts lactic acid, 2 parts nitric acid, 0.1 parts phosphoric acid, 5 parts dimethyl ethanolamine, 2 parts glycerol methyl ether, 1 part pyridine-3-carboxylic acid, 1 part 4-amino-1,2,4-triazole, 0.4 parts hydrofluoric acid, and 38.5 parts water. The concentrations of hydrogen peroxide, lactic acid, phosphoric acid, and hydrofluoric acid are 31 wt%, 88 wt%, 85 wt%, and 49 wt%, respectively.

2. A method for preparing the dual-agent copper-molybdenum-titanium etching solution according to claim 1, characterized in that, The process includes the following steps: mixing the components of the main agent evenly, and mixing the components of the excipients evenly to obtain the final product.

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