Preparation method of high-performance titanium-silicon corrosive liquid for integrated circuit
By preparing an etching solution containing sulfuric acid, hydrogen peroxide, and 3-trifluoroethoxypyridine-2-amine, the selectivity and stability issues of titanium-silicon etching solutions during the etching process were solved, achieving efficient etching of titanium-silicon materials, which is suitable for high-precision patterning and large-scale production of integrated circuits.
Patent Information
- Application Number
- CN202511403605.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-29
- Publication Date
- 2026-02-10
AI Technical Summary
Existing titanium-silicon etching solutions struggle to achieve high selectivity, controllable etching rates, and low surface damage during the etching process, leading to uneven etching and stability issues between titanium and silicon materials, which affect the manufacturing precision and large-scale production of integrated circuits.
A specific etching solution system consisting of sulfuric acid, hydrogen peroxide, 3-trifluoroethoxypyridine-2-amine, 2,2-bipyridine, polyacrylamide, sorbic acid, and ethylenediaminetetraacetic acid is used. By precisely controlling the stirring, dripping, and filtration processes, the acidic environment of the etching solution and metal chelation are ensured, avoiding violent reactions and achieving selective etching of titanium and silicon.
It achieves high-performance etching with titanium-silicon etchant, ensuring stable etching rate and substrate protection, suitable for high-precision patterning of integrated circuits, and suitable for mass production.
Abstract
Description
Technical Field
[0001] This invention belongs to the field of stripping solution preparation and production technology, and particularly relates to a method for preparing a high-performance titanium-silicon etching solution for integrated circuits. Background Technology
[0002] Titanium silicon (TiSi) possesses unique physical and chemical properties, such as a high melting point, good electrical and thermal conductivity, and strong corrosion resistance. These properties make TiSi widely applicable in integrated circuits, for example, as gate materials and interconnect materials. However, these properties also make etching TiSi difficult, requiring the design of special etchants to achieve effective patterning. With the continuous advancement of integrated circuit manufacturing processes and the shrinking of device dimensions, the resolution requirements for patterning processes are becoming increasingly stringent. TiSi etchants play a crucial role in the patterning process, directly affecting the accuracy, uniformity, and stability of the pattern. Due to the different chemical properties of titanium and silicon, the etchant must meet requirements such as high selectivity, controllable etching rate, and low surface damage.
[0003] To address the issue that different titanium-to-silicon selectivity ratios can lead to the etching of titanium nitride or damage to silicon-based materials during etching, hindering large-scale production, we propose a method for preparing a high-performance titanium-silicon etching solution for integrated circuits. Summary of the Invention
[0004] This invention provides a method for preparing a high-performance titanium-silicon etching solution for integrated circuits, in order to solve the problems mentioned in the background art.
[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing a high-performance titanium-silicon etching solution for integrated circuits, comprising the following steps:
[0006] S1. Prepare raw materials: 79%–89% sulfuric acid, 2%–3% hydrogen peroxide, 0.1%–0.3% 3-trifluoroethoxypyridine-2-amine, 0.1%–0.3% 2,2-bipyridine, 0.01%–0.02% polyacrylamide, 0.2%–0.5% sorbic acid, and 0.05%–0.1% ethylenediaminetetraacetic acid;
[0007] S2. In the hydrogen peroxide mixing tank, add 3-trifluoroethoxypyridine-2-amine and 2,2-bipyridine in sequence for premixing. Then, perform magnetic stirring at a speed of 300 r / min to 400 r / min and control the temperature at 23°C. Add polyacrylamide dropwise during stirring and continue stirring for 30 min until the system becomes transparent.
[0008] S3. After the mixing in step S2 is completed, the operator adds sulfuric acid to the mixing tank in three portions and performs magnetic stirring, maintaining the temperature at 23°C during the stirring process.
[0009] S4. After the mixing in step S3 is completed, sorbic acid solution and ethylenediaminetetraacetic acid are added dropwise to the mixing tank at a rate of 0.5 mL / min. During the dropwise addition, magnetic stirring is performed at a rate of 150 r / min to 300 r / min, while maintaining the temperature at 23°C.
[0010] S5. Cool the mixture prepared in step S4 using ice water at a rate of 2℃ / min to 3℃ / min until it reaches 10℃. Then, place the cooled mixture in a -5℃ cold storage and let it stand for 4 hours.
[0011] S6. After cooling is complete, filter the mixture using a filter to obtain a titanium-silicon etching solution.
[0012] Furthermore, in step S1, the sulfuric acid used is industrial-grade concentrated sulfuric acid, and the free sulfur trioxide content needs to be tested in advance to avoid excessive sulfur trioxide causing hydrogen peroxide decomposition; the hydrogen peroxide used is 30% industrial-grade hydrogen peroxide, with the addition of 3-trifluoroethoxypyridine-2-amine and 0.05% to 0.1% ethylenediaminetetraacetic acid as metal chelating agents, which can chelate free metal ions during metal etching and improve the etching rate; sorbic acid is used to adjust the pH value of the solution so that the etching solution is always in an acidic environment to avoid affecting the etching rate.
[0013] Furthermore, in step S2, 40% sulfuric acid is added initially and stirred for 10 minutes until the pH reaches 1.5–2.0; after a 5-minute interval, 30% sulfuric acid is added to maintain the pH at 1.8–2.2; finally, 30% sulfuric acid is added to control the final pH at 2.0–2.5 to avoid violent exothermic reactions; and nitrogen protection is maintained throughout the process to prevent hydrogen peroxide decomposition.
[0014] Furthermore, in step S3, during the addition of sorbic acid and ethylenediaminetetraacetic acid, ultrasonic-assisted dispersion is used, with an ultrasonic frequency of 40 kHz / min for 10 min.
[0015] Furthermore, in step S6, a 0.45μm polyvinylidene fluoride pre-filtration is first used; then a 0.22μm nylon membrane is used for sterilization filtration; and finally a 0.1μm ceramic membrane is used for terminal filtration. Throughout the entire pressure filtration process, the filtration pressure is maintained at 0.15MPa to 0.2MPa.
[0016] The beneficial effects of this invention are:
[0017] 1. This system does not contain fluoride ions;
[0018] 2. By adding chelating agents and corrosion inhibitors, the target metal layer is etched while the substrate is protected;
[0019] 3. The addition of organic acids ensures that the etching solution is always in an acidic environment during etching, which promotes the etching of metallic titanium by hydrogen peroxide.
[0020] 4. The raw materials for this etching solution system are simple and readily available, which is conducive to large-scale promotion. Detailed Implementation
[0021] To further understand the content, features, and effects of this invention, the following embodiments are provided.
[0022] Example 1:
[0023] A method for preparing a high-performance titanium-silicon etching solution for integrated circuits includes the following steps;
[0024] S1. Prepare raw materials: 89% sulfuric acid, 3% hydrogen peroxide, 0.2% 3-trifluoroethoxypyridine-2-amine, 0.2% 2,2-bipyridine, 0.02% polyacrylamide, 0.5% sorbic acid, and 0.05%–0.1% ethylenediaminetetraacetic acid;
[0025] Sulfuric acid: Industrial grade concentrated sulfuric acid should be used. The free sulfur trioxide content needs to be tested in advance to avoid excessive sulfur trioxide causing hydrogen peroxide decomposition.
[0026] Hydrogen peroxide: 30% industrial-grade hydrogen peroxide;
[0027] Adding 3-trifluoroethoxypyridine-2-amine and 0.05%–0.1% ethylenediaminetetraacetic acid as metal chelating agents can chelate free metal ions during metal etching, thereby increasing the etching rate.
[0028] Sorbic acid: Adjusts the pH of the solution to keep the etching solution in an acidic environment and avoids affecting the etching rate.
[0029] S2. In the hydrogen peroxide mixing tank, add 3-trifluoroethoxypyridine-2-amine and 2,2-bipyridine in sequence for premixing. Then, perform magnetic stirring at a speed of 300 r / min to 400 r / min and control the temperature at 23°C. Add polyacrylamide dropwise during stirring and continue stirring for 30 min until the system becomes transparent.
[0030] S3. After the mixing in step S2 is completed, the operator adds sulfuric acid to the mixing tank in three portions and performs magnetic stirring, maintaining the temperature at 23°C during the stirring process.
[0031] Add 40% sulfuric acid initially and stir for 10 minutes until the pH is between 1.5 and 2.0;
[0032] Add 30% sulfuric acid every 5 minutes to maintain the pH at 1.8–2.2;
[0033] Finally, add 30% sulfuric acid to maintain the final pH at 2.0–2.5, avoiding violent exothermic reactions.
[0034] And nitrogen protection is maintained throughout the process to prevent hydrogen peroxide from decomposing;
[0035] S4. After the mixing in step S3 is completed, sorbic acid and ethylenediaminetetraacetic acid are added dropwise to the mixing tank at a rate of 0.5 mL / min. During the dropwise addition, magnetic stirring is performed at a rate of 150 r / min to 300 r / min, while maintaining the temperature at 23°C. During the addition of sorbic acid and ethylenediaminetetraacetic acid, ultrasonic-assisted dispersion is used at a frequency of 40 kHz / min for 10 min.
[0036] S5. Cool the mixture prepared in step S4 using ice water at a rate of 2℃ / min to 3℃ / min until it reaches 10℃. Then, place the cooled mixture in a -5℃ cold storage and let it stand for 4 hours.
[0037] S6. After cooling is complete, the mixture is filtered using a filter, and the filtration pressure is maintained at 0.15MPa to 0.2MPa throughout the entire pressure filtration process to obtain titanium-silicon etching solution.
[0038] First, pre-filter with 0.45μm polyvinylidene fluoride;
[0039] Secondly, a 0.22μm nylon membrane is used for sterilization filtration;
[0040] Finally, a 0.1μm ceramic membrane is used for terminal filtration.
[0041] Example 2:
[0042] S1. Prepare raw materials: 79% sulfuric acid, 2% hydrogen peroxide, 0.1% 3-trifluoroethoxypyridine-2-amine, 0.1% 2,2-bipyridine, 0.01% polyacrylamide, 0.2% sorbic acid, and 0.05%–0.1% ethylenediaminetetraacetic acid;
[0043] Sulfuric acid: Industrial grade concentrated sulfuric acid should be used. The free sulfur trioxide content needs to be tested in advance to avoid excessive sulfur trioxide causing hydrogen peroxide decomposition.
[0044] Hydrogen peroxide: 30% industrial-grade hydrogen peroxide;
[0045] Adding 3-trifluoroethoxypyridine-2-amine and 0.05%–0.1% ethylenediaminetetraacetic acid as metal chelating agents can chelate free metal ions during metal etching, thereby increasing the etching rate.
[0046] Sorbic acid: Adjusts the pH of the solution to keep the etching solution in an acidic environment and avoids affecting the etching rate.
[0047] S2. In the hydrogen peroxide mixing tank, add 3-trifluoroethoxypyridine-2-amine and 2,2-bipyridine in sequence for premixing. Then, perform magnetic stirring at a speed of 300 r / min to 400 r / min and control the temperature at 23°C. Add polyacrylamide dropwise during stirring and continue stirring for 30 min until the system becomes transparent.
[0048] S3. After the mixing in step S2 is completed, the operator adds sulfuric acid to the mixing tank in three portions and performs magnetic stirring, maintaining the temperature at 23°C during the stirring process.
[0049] Add 40% sulfuric acid initially and stir for 10 minutes until the pH is between 1.5 and 2.0;
[0050] Add 30% sulfuric acid every 5 minutes to maintain the pH at 1.8–2.2;
[0051] Finally, add 30% sulfuric acid to maintain the final pH at 2.0–2.5, avoiding violent exothermic reactions.
[0052] And nitrogen protection is maintained throughout the process to prevent hydrogen peroxide from decomposing;
[0053] S4. After the mixing in step S3 is completed, the sorbic acid and ethylenediaminetetraacetic acid solution is added dropwise to the mixing tank at a rate of 0.5 mL / min. During the dropwise addition, magnetic stirring is performed at a rate of 150 r / min to 300 r / min, while maintaining the temperature at 23°C. During the addition of sorbic acid and ethylenediaminetetraacetic acid, ultrasonic-assisted dispersion is used at a frequency of 40 kHz / min for 10 min.
[0054] S5. Cool the mixture prepared in step S4 using ice water at a rate of 2℃ / min to 3℃ / min until it reaches 10℃. Then, place the cooled mixture in a -5℃ cold storage and let it stand for 4 hours.
[0055] S6. After cooling is complete, the mixture is filtered using a filter, and the filtration pressure is maintained at 0.15MPa to 0.2MPa throughout the entire pressure filtration process to obtain titanium-silicon etching solution.
[0056] First, pre-filter with 0.45μm polyvinylidene fluoride;
[0057] Secondly, a 0.22μm nylon membrane is used for sterilization filtration;
[0058] Finally, a 0.1μm ceramic membrane is used for terminal filtration.
[0059] Example 3:
[0060] S1. Prepare raw materials: 89% sulfuric acid, 3% hydrogen peroxide, 0.3% 3-trifluoroethoxypyridine-2-amine, 0.3% 2,2-bipyridine, 0.02% polyacrylamide, 0.5% sorbic acid, and 0.05%–0.1% ethylenediaminetetraacetic acid;
[0061] Sulfuric acid: Industrial grade concentrated sulfuric acid should be used. The free sulfur trioxide content needs to be tested in advance to avoid excessive sulfur trioxide causing hydrogen peroxide decomposition.
[0062] Hydrogen peroxide: 30% industrial-grade hydrogen peroxide;
[0063] Adding 3-trifluoroethoxypyridine-2-amine and 0.05%–0.1% ethylenediaminetetraacetic acid as metal chelating agents can chelate free metal ions during metal etching, thereby increasing the etching rate.
[0064] Sorbic acid: Adjusts the pH of the solution to keep the etching solution in an acidic environment and avoids affecting the etching rate.
[0065] S2. In the hydrogen peroxide mixing tank, add 3-trifluoroethoxypyridine-2-amine and 2,2-bipyridine in sequence for premixing. Then, perform magnetic stirring at a speed of 300 r / min to 400 r / min and control the temperature at 23°C. Add polyacrylamide dropwise during stirring and continue stirring for 30 min until the system becomes transparent.
[0066] S3. After the mixing in step S2 is completed, the operator adds sulfuric acid to the mixing tank in three portions and performs magnetic stirring, maintaining the temperature at 23°C during the stirring process.
[0067] Add 40% sulfuric acid initially and stir for 10 minutes until the pH is between 1.5 and 2.0;
[0068] Add 30% sulfuric acid every 5 minutes to maintain the pH at 1.8–2.2;
[0069] Finally, add 30% sulfuric acid to maintain the final pH at 2.0–2.5, avoiding violent exothermic reactions.
[0070] And nitrogen protection is maintained throughout the process to prevent hydrogen peroxide from decomposing;
[0071] S4. After the mixing in step S3 is completed, the sorbic acid and ethylenediaminetetraacetic acid solution is added dropwise to the mixing tank at a rate of 0.5 mL / min. During the dropwise addition, magnetic stirring is performed at a rate of 150 r / min to 300 r / min, while maintaining the temperature at 23°C. During the addition of sorbic acid and ethylenediaminetetraacetic acid, ultrasonic-assisted dispersion is used at a frequency of 40 kHz / min for 10 min.
[0072] S5. Cool the mixture prepared in step S4 using ice water at a rate of 2℃ / min to 3℃ / min until it reaches 10℃. Then, place the cooled mixture in a -5℃ cold storage and let it stand for 4 hours.
[0073] S6. After cooling is complete, the mixture is filtered using a filter, and the filtration pressure is maintained at 0.15MPa to 0.2MPa throughout the entire pressure filtration process to obtain titanium-silicon etching solution.
[0074] First, pre-filter with 0.45μm polyvinylidene fluoride;
[0075] Secondly, a 0.22μm nylon membrane is used for sterilization filtration;
[0076] Finally, a 0.1μm ceramic membrane is used for terminal filtration.
[0077] Table 1 Corrosive solutions from Examples 1-3
[0078] project Titanium ions (mg / g) Silicon ions (mg / g) Example 1 367.5 329.5 Example 2 259.3 223.4 Example 3 104.6 150.7
[0079] As can be seen from the above embodiments, the method of the present invention can control the etching rate in the preparation of a titanium-silicon etching solution system, thereby avoiding unstable etching rate and causing residue or damage to the substrate.
[0080] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.
Claims
1. A method for preparing a high-performance titanium-silicon etching solution for integrated circuits, characterized in that: Includes the following steps: S1. Prepare raw materials: 79%–89% sulfuric acid, 2%–3% hydrogen peroxide, 0.1%–0.3% 3-trifluoroethoxypyridine-2-amine, 0.1%–0.3% 2,2-bipyridine, 0.01%–0.02% polyacrylamide, 0.2%–0.5% sorbic acid, and 0.05%–0.1% ethylenediaminetetraacetic acid; S2. In the hydrogen peroxide mixing tank, add 3-trifluoroethoxypyridine-2-amine and 2,2-bipyridine in sequence for premixing. Then, perform magnetic stirring at a speed of 300 r / min to 400 r / min and control the temperature at 23°C. Add polyacrylamide dropwise during stirring and continue stirring for 30 min until the system becomes transparent. S3. After the mixing in step S2 is completed, the operator adds sulfuric acid to the mixing tank in three portions and performs magnetic stirring, maintaining the temperature at 23°C during the stirring process. S4. After the mixing in step S3 is completed, sorbic acid solution and ethylenediaminetetraacetic acid are added dropwise to the mixing tank at a rate of 0.5 mL / min. During the dropwise addition, magnetic stirring is performed at a rate of 150 r / min to 300 r / min, while maintaining the temperature at 23°C. S5. Cool the mixture prepared in step S4 using ice water at a rate of 2℃ / min to 3℃ / min until it reaches 10℃. Then, place the cooled mixture in a -5℃ cold storage and let it stand for 4 hours. S6. After cooling is complete, the following features are provided: In step S1, sulfuric acid: industrial-grade concentrated sulfuric acid is selected, and the free sulfur trioxide content needs to be detected in advance to avoid excessive sulfur trioxide causing hydrogen peroxide decomposition; hydrogen peroxide: 30% concentration industrial-grade hydrogen peroxide is used, with the addition of 3-trifluoroethoxypyridine-2-amine and 0.05%~0.1% ethylenediaminetetraacetic acid as metal chelating agents, which can chelate free metal ions during metal etching and improve the etching rate; sorbic acid: adjusts the pH value of the solution to keep the etching solution in an acidic environment to avoid affecting the etching rate.
2. The method for preparing a high-performance titanium-silicon etching solution for integrated circuits according to claim 1, characterized in that: In step S2, 40% sulfuric acid is added initially and stirred for 10 minutes until the pH is controlled at 1.5-2.0; after a 5-minute interval, 30% sulfuric acid is added to maintain the pH at 1.8-2.2; finally, 30% sulfuric acid is added to control the final pH at 2.0-2.5 to avoid violent exothermic reactions; and nitrogen protection is maintained throughout the process to prevent hydrogen peroxide decomposition.
3. The method for preparing a high-performance titanium-silicon etching solution for integrated circuits according to claim 1, characterized in that: In step S3, during the addition of sorbic acid and ethylenediaminetetraacetic acid, ultrasonic-assisted dispersion is used at a frequency of 40 kHz / min for 10 min.
4. The method for preparing a high-performance titanium-silicon etching solution for integrated circuits according to claim 1, characterized in that: In step S6, a 0.45μm polyvinylidene fluoride pre-filtration is first used; then a 0.22μm nylon membrane is used for sterilization filtration; and finally a 0.1μm ceramic membrane is used for terminal filtration. Throughout the entire pressure filtration process, the filtration pressure is maintained at 0.15MPa to 0.2MPa.