High-stability titanium etching solution as well as preparation method and application thereof

Abstract

The invention relates to a high-stability titanium etching solution as well as a preparation method and application thereof. The high-stability titanium etching solution comprises the following components in parts by weight: 10-30 parts of hydrogen peroxide; 3-15 parts of a flavonoid compound and a flavonoid derivative; 1-10 parts of acyl-modified amino acid compounds and derivatives; 5-15 parts of guanidyl compound and derivative; and 30-70 parts of ultrapure water. The flavonoid compound can capture oxygen free radicals, and generation of the oxygen free radicals in the hydrogen peroxide decomposition process is reduced. The acyl-modified amino acid compound and the derivative have relatively strong oxidation resistance, and hydrogen peroxide can be stabilized through complexation, and the hydrogen peroxide, the flavonoid compound and the derivative can jointly reduce the decomposition rate of the hydrogen peroxide and enhance the stability of the hydrogen peroxide. And the flavonoid compound, the flavonoid derivative, the guanidyl compound and the guanidyl derivative can improve the etching effect of titanium metal etching, all the components cooperate together to avoid self-decomposition of hydrogen peroxide to a greater extent, and the stability of the etching liquid is improved.

Description

Technical Field

[0001] The present invention belongs to the field of semiconductor manufacturing processes, and particularly relates to a highly stable titanium etchant and its preparation method and application. Background Art

[0002] In the field of semiconductor manufacturing, titanium (Ti) and its alloys are widely used in chip interconnection, diffusion barrier layers, and electrode materials. However, in the process of microelectronic device processing, removing or patterning the titanium thin film is a key step, which usually requires a highly selective and high-precision etching process. Therefore, the titanium etchant plays a crucial role in semiconductor manufacturing.

[0003] Titanium has relatively high chemical stability, making it difficult to be removed by traditional etching methods. Common etching methods include wet etching and dry etching, but each has its own advantages and disadvantages in terms of precision, etching rate, and process compatibility.

[0004] Among them, wet etching uses a specific chemical etchant to dissolve the titanium film, mainly relying on the oxidation-dissolution mechanism. Due to its high selectivity, it can optimize the formula for different materials, be suitable for large-area uniform etching, and has relatively low equipment requirements and low costs. Therefore, it is widely used in the etching of titanium metal layers. The titanium etchant plays an important role in the fields of semiconductor device manufacturing, micro-electromechanical systems (MEMS), optoelectronic devices, etc. Its main applications include the removal of titanium and titanium alloy thin films, the patterning of titanium masks, and the cleaning and residue removal of titanium metal.

[0005] With the development of semiconductor technology towards smaller line widths and higher integration levels, future titanium etchants will also pay more attention to high-precision, high-selectivity, and high-stability etching technologies to provide better solutions for advanced semiconductor manufacturing.

[0006] Alkaline hydrogen peroxide etchants not only have low corrosiveness but also high selectivity. However, to highly avoid the self-decomposition of hydrogen peroxide, a highly stable system that meets the requirements of semiconductor metal etching for titanium etchants is urgently needed. Summary of the Invention

[0007] The technical problem solved by the present invention: To more greatly avoid the self-decomposition of hydrogen peroxide and improve the stability of the etchant.

[0008] In view of the technical problems existing in the prior art, the present invention designs a highly stable titanium etchant and its preparation method and application.

[0009] It should be noted that in the present invention, unless otherwise specified, the specific meaning of "including" involving compositional limitations and descriptions includes both the open-ended meanings of "including", "comprising", etc. and their similar meanings, as well as the closed-ended meanings of "consisting of..." and their similar meanings.

[0010] To solve the above-mentioned existing technical problems, the present invention adopts the following solutions:

[0011] A highly stable titanium etchant, calculated by weight, includes the following components:

[0012] Hydrogen peroxide 10 - 30 parts;

[0013] Flavonoid compounds and derivatives 3 - 15 parts;

[0014] Acyl-modified amino acid compounds and derivatives 1 - 10 parts;

[0015] Guanidine compounds and derivatives 5 - 15 parts;

[0016] Ultra-pure water 30 - 70 parts.

[0017] Further, the flavonoid compounds and derivatives are one or more of quercetin-3-O-glucoside, kaempferol-3-O-glucoside, quercetin-3-O-neohesperidoside, luteolin 7-rutinoside, hesperetin-7-O-rutinoside.

[0018] Further, the acyl-modified amino acid compounds and derivatives are one or more of N-acetylglycine, N-acetyl-L-serine, N-formyl-L-leucine, N-succinyl-L-proline, N-succinyl-L-tyrosine, 3-maleimidopropionic acid, N-formyl-L-aspartic acid, N-acetyl-L-cysteine.

[0019] Further, the guanidine compounds and derivatives are one or more of guanidine, 1,1,3,3-tetramethylguanidine, polyhexamethylene biguanide, N,N',N”-triaminoguanidine, aminoguanidine, metformin, diaminoguanidine, ethylguanidine.

[0020] The present invention also discloses a preparation method of the above-mentioned highly stable titanium etchant, including the following steps:

[0021] Step 1: Weigh hydrogen peroxide, flavonoid compounds and derivatives, acyl-modified amino acid compounds and derivatives, guanidine compounds and derivatives, ultra-pure water respectively according to the ratio;

[0022] Step 2: Stir the components weighed in Step 1 at room temperature until all the materials are completely dissolved, thus obtaining the highly stable titanium etchant.

[0023] Further, in the above-mentioned Step 2, the stirring speed at room temperature is 100 - 1500 r / min, and the stirring time is 10 - 25 min.

[0024] The present invention also discloses an etching method for the above-mentioned highly stable titanium etching solution, comprising the following steps:

[0025] Step 1: Heat the above-mentioned highly stable titanium etching solution, and immerse the wafer containing the titanium layer in the etching solution to obtain the immersed wafer;

[0026] Step 2: Put the immersed wafer obtained in Step 1 into ultrapure water, rinse it at least twice, and then dry the surface water stains with an ultrapure nitrogen gas flow, thus completing the surface etching treatment of the wafer.

[0027] Further, in Step 1, heat the above-mentioned highly stable titanium etching solution to 20 - 35 °C, and immerse the wafer containing the titanium layer in the etching solution for 1 - 10 minutes.

[0028] The present invention also discloses the use of the above-mentioned highly stable titanium etching solution in the field of metal etching.

[0029] In the present invention, each component of the highly stable titanium etching solution can be optimized to optimize the effect of the etching solution. Among them, hydrogen peroxide is preferably 12 - 21 parts; flavonoid compounds and derivatives are preferably 5 - 13 parts; acyl-modified amino acid compounds and derivatives are preferably 2 - 5 parts; guanidine compounds and derivatives are preferably 6 - 13 parts; ultrapure water is preferably 45 - 60 parts.

[0030] In the present invention, the flavonoid compounds and derivatives are preferably quercetin-3-O-neohesperidin and / or luteolin 7-rutinoside.

[0031] In the present invention, the acyl-modified amino acid compounds and derivatives are preferably one or more of N-succinyl-L-proline, N-succinyl-L-tyrosine, or 3-maleimidopropionic acid.

[0032] In the present invention, the guanidine compounds and derivatives are preferably one or more of guanidine, polyhexamethylene biguanide, or N,N',N''-triaminoguanidine.

[0033] In the present invention, hydrogen peroxide plays a crucial role in the etching process as an important component in the etching solution due to its strong oxidizing property and high selectivity for specific metals. The specific reaction equation is as follows:

[0034] H 2 O 2 +HOO - →O 2 ↑+OH - +H 2 O

[0035] H 2 O 2 +OH- →HOO - +H 2 O

[0036] Ti + HOO - + 3OH - →Ti(OH) 2 O 2 + H 2 O + 4e -

[0037]

[0038] In the present invention, flavonoids and derivatives play a crucial role in the etching of titanium metal:

[0039] First, antioxidant effect: Flavonoids usually have good antioxidant properties, can capture free radicals in the system, avoid the acceleration of the etching rate caused by enhancing the oxidation performance of the etching solution and the oxidation reaction on the titanium surface, slow down its decomposition and oxidation reaction rates, and maintain the stability of the etching solution at the same time.

[0040] Second, corrosion inhibition and rate control effect: Flavonoids and derivatives have a certain corrosion inhibition effect, can slow down the etching of alkaline hydrogen peroxide on the titanium metal surface, stabilize the pH value and ion concentration of the etching solution, make the etching process more controllable, thereby adjusting the etching rate and improving the stability of the etching solution.

[0041] Third, surfactant effect: Flavonoids have the properties of surfactants, which helps the etching solution to adhere more evenly to the titanium surface and improve the etching effect.

[0042] In the present invention, acyl-modified amino acid compounds and derivatives act as organic complexes in the etching solution, and their functions are as follows:

[0043] First, metal chelation effect. The presence of functional groups such as carboxyl (-COOH), amino (-NH 2 ), and acyl (-CO-R) in its structure can effectively chelate metals (such as Ti 4+ ).

[0044] Second, relieve the decomposition of hydrogen peroxide. Multiple carboxyl groups (-COOH) in the structure can stabilize H 2 O 2 through a hydrogen bond network. Acetyl and formyl groups can form hydrogen bonds to further stabilize H 2 O 2 and prevent its rapid decomposition.

[0045] The present invention provides a highly stable titanium etching solution, its preparation method and application, which have the following beneficial effects:

[0046] 1. The highly stable titanium etchant of the present invention uses flavonoid compounds and derivatives, acyl-modified amino acid compounds and derivatives, and guanidine compounds and derivatives to synergistically achieve the effect of stabilizing hydrogen peroxide. In the highly stable titanium etchant of the present invention, flavonoid compounds can capture oxygen free radicals or other oxidizing substances, reducing the generation of oxygen free radicals during the decomposition of hydrogen peroxide. This antioxidant effect helps to slow down the decomposition rate of hydrogen peroxide. Secondly, functional groups such as hydroxyl or carbonyl in flavonoid compounds and derivatives can form complexes with metal ions in hydrogen peroxide, stabilizing the structure of hydrogen peroxide molecules and reducing their decomposition. This complexation effect can effectively delay the decomposition reaction of hydrogen peroxide. The acyl-modified amino acid compounds and derivatives in the highly stable titanium etchant of the present invention have strong antioxidant properties and can, through complexation, stabilize hydrogen peroxide together with flavonoid compounds and derivatives, reducing the decomposition rate of hydrogen peroxide and enhancing its stability.

[0047] 2. In the highly stable titanium etchant of the present invention, the use of flavonoid compounds and derivatives and guanidine compounds and derivatives can improve the etching effect of titanium metal etching. Flavonoid compounds and derivatives and guanidine compounds and derivatives have surfactant properties, helping the etchant to adhere more uniformly to the titanium surface, while acyl-modified amino acid compounds and derivatives may enhance the interaction between the liquid and the solid surface, improving the etching effect. Detailed implementation mode

[0048] The following is a further description of the present invention in combination with specific embodiments:

[0049] Table 1 Examples 1-7

[0050]

[0051]

[0052] Table 2 Comparative Examples 1-3

[0053]

[0054] Table 3 Test data

[0055]

[0056]

[0057] Regarding the preparation method of the highly stable titanium etchant of the present invention, it includes the following steps:

[0058] Step 1: Weigh 30% hydrogen peroxide, flavonoid compounds and derivatives, acyl-modified amino acid compounds and derivatives, guanidine compounds and derivatives, and ultrapure water respectively.

[0059] Step 2: Add the mixed components into a container, stir at a speed of 1400 r / min at room temperature for 15 min until all the materials are completely dissolved, thus obtaining the etching solution.

[0060] The etching solutions in the comparative examples were all prepared with reference to the method in Example 1.

[0061] Regarding the etching method of the high-stability titanium etching solution of the present invention, it includes the following steps:

[0062] Step 1: Heat the high-stability titanium etching solution to 23°C with a constant-temperature water bath, and immerse the wafer with a titanium layer in the etching solution to obtain the immersed wafer.

[0063] Step 2: Put the immersed wafer into ultrapure water, rinse it twice, and then blow dry the water stains on the surface with an ultrapure nitrogen gas stream, thus completing the surface etching treatment of the wafer.

[0064] Regarding performance testing and description:

[0065] The test method for Performance 1, the hydrogen peroxide decay rate, is as follows:

[0066] Apply an automatic potentiometric titrator, take samples from the examples and comparative examples respectively, titrate the hydrogen peroxide content in the etching solution with potassium permanganate as the standard solution, and calculate the hydrogen peroxide decay rate.

[0067] The test method for Performance 2, the etching rate decay rate, is as follows:

[0068] Under the test condition of 23°C, immerse a wafer with a titanium layer thickness of 2 The titanium layer thickness is 2×2 cm into the titanium etching solution, take it out after timing, rinse the residual liquid on the surface with ultrapure water and blow dry it with an ultrapure nitrogen gas stream, test the film thickness before and after etching through a four-probe resistivity tester, and obtain the etching rate through calculation. Measure the etching rate of the etching solution after standing for 14 days, and calculate the etching rate decay rate.

[0069] Make a further comparative description through the tabular data in the specification:

[0070] Table 1 and Table 2 show the comparison of each component of the high-stability titanium etching solution of Examples 1-7 of the present invention with Comparative Examples 1-3 for metallic titanium.

[0071] It can be seen from the test data in Table 3 that in the examples of the present invention, the hydrogen peroxide decay amount is 8.74% - 12.6%; while in the comparative examples, the hydrogen peroxide decay amount is 20.61% - 24.43%, indicating that the etching solution in the examples of the present invention has a good hydrogen peroxide stability effect.

[0072] Similarly, as can be seen from Table 3, the etching rate attenuation rate of the embodiments of the present invention within 14 days is 18.87%-24.93%; while in the comparative examples, the etching rate attenuation rate reaches 43.27%-47.62%.

[0073] In Comparative Example 1, due to the reduced ability of its capture system to capture free radicals, hydrogen peroxide undergoes self-decomposition, and the increase in free metal ions in the solution promotes the decomposition of hydrogen peroxide;

[0074] In Comparative Example 2, since the acyl-modified amino acid compound was replaced with a common amino acid compound, the complexation with free metal was reduced, thereby reducing the system stability;

[0075] In Comparative Example 3, since the guanidine compound was replaced with a common inorganic base, the ability of the system to scavenge free radicals and complex with metals was reduced. Therefore, the effect of the comparative example is less stable than that of the embodiment. It shows that the etching solution of the embodiment of the present invention has stronger stability, smaller etching rate attenuation, and the etching solution is relatively more stable.

[0076] In the present invention, flavonoid compounds can capture oxygen free radicals and reduce the generation of oxygen free radicals during the decomposition of hydrogen peroxide. The acyl-modified amino acid compounds and derivatives have strong antioxidant properties, and can stabilize hydrogen peroxide through complexation. The flavonoid compounds and derivatives and the guanidine compounds and derivatives together reduce the decomposition rate of hydrogen peroxide and enhance its stability. The flavonoid compounds and derivatives and the guanidine compounds and derivatives can improve the etching effect of titanium metal etching. Each component works together synergistically to avoid the self-decomposition of hydrogen peroxide to a greater extent and improve the stability of the etching solution.

[0077] The present invention has been described exemplarily in combination with the embodiments above. Obviously, the implementation of the present invention is not limited by the above methods. As long as various improvements are made by adopting the method concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A high stability titanium etching solution, characterized in that: Calculated by weight, it includes the following components: 10-30 parts of hydrogen peroxide; 3-15 parts of flavonoids and their derivatives; 1-10 parts of acyl-modified amino acid compounds and derivatives; 5-15 parts of guanidine compounds and derivatives; 30-70 parts of ultrapure water.

2. The high stability titanium etching solution according to claim 1, characterized in that: The flavonoid compound and its derivative are one or more of quercetin-3-O-glucoside, kaempferol-3-O-glucoside, quercetin-3-O-neohesperidin, luteolin-7-rutinoside and hesperetin-7-O-rutinoside.

3. The high stability titanium etching solution according to claim 1, characterized in that: The acyl-modified amino acid compound and derivative are one or more of N-acetylglycine, N-acetyl-L-serine, N-formyl-L-leucine, N-succinyl-L-proline, N-succinyl-L-tyrosine, 3-maleimidopropionic acid, N-formyl-L-aspartic acid, and N-acetyl-L-cysteine.

4. The high stability titanium etching solution according to claim 1, characterized in that: The guanidine compound and its derivatives are one or more of guanidine, 1,1,3,3-tetramethylguanidine, polyhexamethylene biguanide, N,N',N"triaminoguanidine, aminoguanidine, metformin, diaminoguanidine and ethylguanidine.

5. A method for preparing the high-stability titanium etching solution according to any one of claims 1 to 4, characterized in that: The steps include: Step 1: Weigh hydrogen peroxide, flavonoid compounds and derivatives, acyl-modified amino acid compounds and derivatives, guanidine compounds and derivatives, and ultrapure water respectively according to proportion; Step 2: Stir the components weighed in step 1 at room temperature until all materials are completely dissolved to obtain the high-stability titanium etching solution.

6. The method for preparing a high stability titanium etching solution according to claim 5, characterized in that: In the step 2, the stirring speed is 100-1500 r / min at room temperature, and the stirring time is 10-25 min.

7. An etching method for the high-stability titanium etching solution according to any one of claims 1 to 4, characterized in that: The following steps are included: Step 1: heating the high-stability titanium etching solution, and immersing a wafer containing a titanium layer in the etching solution to obtain an immersed wafer; Step 2: Place the soaked wafer in step 1 into ultrapure water, rinse at least twice, and then use ultrapure nitrogen flow to dry the surface water stains, thereby completing the surface etching process of the wafer.

8. The method for preparing a high stability titanium etching solution according to claim 7, characterized in that: In the step 1, the high-stability titanium etching solution is heated to 20-35° C., and the wafer containing the titanium layer is immersed in the etching solution for 1-10 minutes.

9. Use of the high-stability titanium etching solution according to any one of claims 1 to 4 in the field of metal etching.

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