An acidic silicon etching solution capable of effectively regulating etching brightness

Abstract

This invention discloses an acidic silicon etching solution for effectively controlling etching brightness in the field of semiconductor material processing technology. The etching solution is composed of ammonium bifluoride, nitric acid, sulfuric acid, silver nitrate, surfactant, boron compound additives, and ultrapure water. The boron compound additives exhibit good solubility in the acidic etching solution, effectively regulating the attack of fluoride ions on the silicon surface oxide layer, thereby achieving control over the etching process and the regulation of the surface brightness after etching. The etching solution described in this invention can be used for acidic etching of both monocrystalline and polycrystalline silicon. By adjusting the composition and content of the boron compound additives, silicon etching effects with different brightness levels at the same time and similar brightness levels at different times can be achieved, meeting the etching index requirements for silicon surface state in different application scenarios.

Description

Technical Field

[0001] This invention relates to the field of semiconductor material processing technology, and more specifically to an acidic silicon etching solution for effectively controlling etching brightness. Background Technology

[0002] With the rapid advancement of modern electronic information technology, semiconductor materials, as their core foundation, are receiving increasing attention for their processing technology and quality control. Silicon, as the cornerstone of the semiconductor industry, is widely used in the manufacture of integrated circuits, discrete devices, and various sensors. In the silicon device manufacturing process, surface etching is a crucial step, directly determining the microscopic morphology and macroscopic quality of the silicon wafer surface. However, with the increasing complexity and precision of device structures, different application scenarios place drastically different requirements on the surface condition of silicon materials. For high-end semiconductor chips and power devices, extremely high surface smoothness and specular reflectivity are key to ensuring stable device operation, as a high-brightness surface typically means fewer interface defects and higher breakdown voltage, significantly improving product reliability. However, in optoelectronic fields, such as photodetectors or photosensors, excessive specular reflection can cause optical path interference and stray light problems. Therefore, the industry tends to use silicon materials with low reflectivity and a matte finish to enhance light absorption efficiency and improve sensor sensitivity. Therefore, how to flexibly control the surface brightness after etching under the same process system to meet the diverse needs from mirror finish to matte finish has become an urgent problem to be solved in the current semiconductor wet processing technology.

[0003] Currently, the industry commonly uses the classic hydrofluoric acid and nitric acid system for wet etching of silicon materials. The reaction mechanism of this system is mainly based on the synergistic effect of oxidation and dissolution. In the initial stage of the reaction, the highly oxidizing acid rapidly forms a dense oxide film on the silicon surface. Subsequently, a complexing agent dissolves this oxide layer, thereby removing the material. However, this classic etching system has significant technical bottlenecks. Its most prominent drawback is the extremely fast reaction rate, which is difficult to control precisely. Due to the lack of a self-limiting mechanism in the dissolution process, once the oxide layer is formed, the complexation reaction continues, causing the etching depth to increase rapidly over time. This rapid reaction kinetics results in an extremely narrow process window, making it difficult for operators to intervene precisely on a millisecond-scale timescale. More importantly, this rapid etching is often accompanied by drastic changes in surface brightness, which can cause significant visual differences in a short period. For large-scale industrial production, this elusive brightness fluctuation greatly increases the difficulty of quality control, leading to unstable product yields and failing to meet the stringent requirements for surface consistency and repeatability in mid-to-high-end devices.

[0004] To address the shortcomings of existing technologies, this invention aims to provide a novel acidic silicon etching solution and its preparation method. The core idea of ​​this invention lies in introducing specific functional additives to fundamentally alter the reaction kinetics of the etching solution. By introducing specific boron-containing compounds into the formulation, their unique chemical properties effectively regulate the concentration and attack power of active ions in the etching solution. This regulatory mechanism not only significantly reduces the reaction rate, making the etching process gentler and easier to control, but more importantly, it endows the etching solution with unprecedented brightness control capabilities. By precisely adjusting the additive ratio, operators can flexibly control the surface optical properties after etching within a wide range, thereby achieving arbitrary transitions from high-brightness mirror surfaces to low-brightness matte surfaces. This invention not only solves the problems of excessively rapid reactions and difficult control in traditional processes, but also provides a highly flexible and adaptable surface treatment solution for semiconductor manufacturing, greatly enriching the processing methods for silicon materials. Summary of the Invention

[0005] The purpose of this invention is to provide an acidic silicon etching solution that can effectively control the etching brightness. It solves the technical problem that the reaction rate of existing acidic silicon etching solutions is too fast and difficult to control, resulting in inconsistent brightness of the silicon wafer surface after etching, which cannot meet the different surface state requirements of different application scenarios.

[0006] The present invention achieves the above objectives through the following technical solutions: An acidic silicon etching solution for effectively controlling etching brightness, comprising, by mass percentage: Ammonium bifluoride: 2-7%; Nitric acid: 1.5-8.5%; Silver nitrate: 0.01-0.1%; Surfactant: 0.1-0.5%; Boron compound additives: 0.05-0.4%; Sulfuric acid: Balance.

[0007] In the acidic silicon etching solution for effectively controlling etching brightness described in this invention, ammonium bifluoride is used to etch the silicon dioxide on the surface; nitric acid is used to oxidize the silicon surface to form a silicon dioxide layer; sulfuric acid is used to provide an oxidizing environment in conjunction with nitric acid; a surfactant is used to reduce the surface tension of the etching solution, improve the surface smoothness after etching, and eliminate discoloration problems; silver nitrate is used to drive oxidation and dissolution by utilizing the hole injection effect, in conjunction with controlling the etching rate, and catalyzing the etching reaction; boron compound additives are used to complex the F in the solution. - Ions control the etching process and regulate the etching brightness.

[0008] According to a preferred embodiment of the present invention, the surfactant is selected from at least one of p-nitrobenzenesulfonic acid, 3-nitrobenzenesulfonic acid, p-toluenesulfonic acid, polystyrenesulfonic acid, sodium dodecylbenzenesulfonate, and sodium dodecyl sulfonate.

[0009] According to a preferred embodiment of the present invention, the surfactant is polystyrene sulfonic acid.

[0010] According to a preferred embodiment of the present invention, the boron compound additive is selected from at least one of boric acid, ammonium tetrafluoroborate, sodium octaborate tetrahydrate, and sodium borate tetrahydrate.

[0011] According to a preferred embodiment of the present invention, the boron compound additive is boric acid.

[0012] According to a preferred embodiment of the present invention, the mass concentration of the hydrogen fluoride is 38-42%; and the mass concentration of the nitric acid is 68-70%.

[0013] According to a preferred embodiment of the present invention, the mass concentration of the sulfuric acid is 63-68%.

[0014] According to a preferred embodiment of the present invention, the preparation method of the acidic silicon etching solution with effective control of etching brightness includes the following steps: S1, mixing sulfuric acid with ultrapure water to obtain a sulfuric acid solution; S2, adding ammonium bifluoride, nitric acid, silver nitrate, surfactant and boron compound additives to the sulfuric acid solution in sequence, and stirring.

[0015] According to a preferred embodiment of the present invention, in step S1, the resistivity of the ultrapure water is 18.2 MΩ·cm.

[0016] According to a preferred embodiment of the present invention, in step S2, the stirring time is 1-2 hours.

[0017] The beneficial effects of this invention are as follows: The most significant technical advantage of the acidic silicon etching solution provided by this invention lies in its ability to precisely and effectively control the etching brightness of silicon wafer surfaces. By introducing specific boron compound additives in synergy with silver nitrate, the kinetic balance of oxidation and dissolution reactions in traditional etching systems is altered. Boron compounds can form stable complex structures in an acidic environment, effectively slowing down the attack rate of fluoride ions on the silicon surface oxide layer, thus making the etching process gentle and controllable. This mechanism allows operators to obtain different surface states, from high-brightness mirror finishes to low-brightness matte finishes, under the same process conditions by adjusting the amount of additives. This greatly satisfies the differentiated surface reflectivity requirements of power devices and optoelectronic devices, solving the technical problem of unadjustable brightness caused by excessively rapid reactions in traditional formulations.

[0018] This invention also demonstrates significant advantages in improving surface quality and process stability. The specific surfactants selected in the formulation significantly reduce the surface tension of the etching solution, enhancing its wettability and spreading uniformity on the silicon wafer surface, effectively preventing etching lines or spots caused by localized reaction differences. Simultaneously, the use of high-resistivity ultrapure water as a solvent during preparation, along with thorough mixing, ensures high dispersion and stability of each component within the system, reducing the risk of defects introduced by impurity ions. This optimized formulation and process combination results in extremely low surface roughness and significantly improved flatness of the etched silicon wafer, thereby greatly improving the yield and product consistency of subsequent processing steps, making it suitable for the precision processing of large-size silicon wafers.

[0019] This invention also possesses excellent environmental friendliness and economic applicability, with broad prospects for industrial application. Compared to traditional high-concentration hydrofluoric acid systems, this solution uses sulfuric acid as a base, combined with corrosion inhibitors, reducing the overall consumption of highly corrosive acid solutions and alleviating the environmental pressure of wastewater treatment. The raw materials are widely available and cost-controllable, and the preparation process is simple and easy to understand, enabling large-scale production without complex equipment. Furthermore, this etching solution has a long service life and stable performance, reducing downtime and resource waste caused by frequent solution preparation. In summary, this invention not only achieves breakthroughs in technical indicators but also provides practical solutions for cost control and green manufacturing, bringing significant economic and social benefits to the field of semiconductor material surface treatment. Attached Figure Description

[0020] Appendix Figure 1 This is a comparison chart of the results of Example 7 and Example 12.

[0021] Appendix Figure 2 This is a morphology diagram of the silicon material after etching in Example 12.

[0022] Appendix Figure 3 This is a surface morphology diagram of the silicon material after etching in Example 7. Detailed Implementation

[0023] The present application will now be described in further detail with reference to the accompanying drawings. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0024] Example 1 This embodiment provides a method for preparing an acidic silicon etching solution that effectively controls etching brightness, comprising the following steps: S1. Electronic grade concentrated sulfuric acid is mixed with ultrapure water with a resistivity of 18.2 MΩ·cm to prepare a sulfuric acid solution with a mass concentration of 63%. S2. Add 39g of ammonium bifluoride, 30g of 68% nitric acid, 0.2g of silver nitrate, 3g of p-toluenesulfonic acid, and 1.1g of boric acid to the above sulfuric acid solution in sequence, and stir for 1 hour to obtain an acidic silicon etching solution.

[0025] Example 2 This embodiment provides a method for preparing an acidic silicon etching solution that effectively controls etching brightness, comprising the following steps: S1. Electronic grade concentrated sulfuric acid is mixed with ultrapure water with a resistivity of 18.2 MΩ·cm to prepare a sulfuric acid solution with a mass concentration of 63%. S2. Add 39g of ammonium bifluoride, 30g of 68% nitric acid, 0.2g of silver nitrate, 3g of p-toluenesulfonic acid, and 2g of boric acid to the above sulfuric acid solution in sequence, and stir for 1 hour to obtain an acidic silicon etching solution.

[0026] Example 3 This embodiment provides a method for preparing an acidic silicon etching solution that effectively controls etching brightness, comprising the following steps: S1. Electronic grade concentrated sulfuric acid is mixed with ultrapure water with a resistivity of 18.2 MΩ·cm to prepare a sulfuric acid solution with a mass concentration of 63%. S2. Add 39g of ammonium bifluoride, 30g of nitric acid with a mass concentration of 68%, 0.2g of silver nitrate, 3g of p-toluenesulfonic acid, and 2.8g of boric acid to the above sulfuric acid solution in sequence, and stir for 1 hour to obtain an acidic silicon etching solution.

[0027] Example 4 This embodiment provides a method for preparing an acidic silicon etching solution that effectively controls etching brightness, comprising the following steps: S1. Electronic grade concentrated sulfuric acid is mixed with ultrapure water with a resistivity of 18.2 MΩ·cm to prepare a sulfuric acid solution with a mass concentration of 63%. S2. Add 50g of ammonium bifluoride, 30g of nitric acid with a mass concentration of 68%, 0.2g of silver nitrate, 3g of p-toluenesulfonic acid, and 2.8g of boric acid to the above sulfuric acid solution in sequence, and stir for 1 hour to obtain an acidic silicon etching solution.

[0028] Example 5 This embodiment provides a method for preparing an acidic silicon etching solution that effectively controls etching brightness, comprising the following steps: S1. Electronic grade concentrated sulfuric acid is mixed with ultrapure water with a resistivity of 18.2 MΩ·cm to prepare a sulfuric acid solution with a mass concentration of 63%. S2. Add 39g of ammonium bifluoride, 30g of 68% nitric acid, 0.2g of silver nitrate, 1g of polystyrene sulfonic acid, and 2g of boric acid to the above sulfuric acid solution in sequence, and stir for 1 hour to obtain an acidic silicon etching solution.

[0029] Example 6 This embodiment provides a method for preparing an acidic silicon etching solution that effectively controls etching brightness, comprising the following steps: S1. Electronic grade concentrated sulfuric acid is mixed with ultrapure water with a resistivity of 18.2 MΩ·cm to prepare a sulfuric acid solution with a mass concentration of 63%. S2. Add 39g of ammonium bifluoride, 30g of 68% nitric acid, 0.2g of silver nitrate, 3g of polystyrene sulfonic acid, and 2g of boric acid to the above sulfuric acid solution in sequence, and stir for 1 hour to obtain an acidic silicon etching solution.

[0030] Example 7 This embodiment provides a method for preparing an acidic silicon etching solution that effectively controls etching brightness, comprising the following steps: S1. Electronic grade concentrated sulfuric acid is mixed with ultrapure water with a resistivity of 18.2 MΩ·cm to prepare a sulfuric acid solution with a mass concentration of 63%. S2. Add 39g of ammonium bifluoride, 30g of 68% nitric acid, 0.2g of silver nitrate, 3g of polystyrene sulfonic acid, and 2.8g of boric acid to the above sulfuric acid solution in sequence, and stir for 1 hour to obtain an acidic silicon etching solution.

[0031] Example 8 This embodiment provides a method for preparing an acidic silicon etching solution that effectively controls etching brightness, comprising the following steps: S1. Electronic grade concentrated sulfuric acid is mixed with ultrapure water with a resistivity of 18.2 MΩ·cm to prepare a sulfuric acid solution with a mass concentration of 63%. S2. Add 39g of ammonium bifluoride, 30g of 68% nitric acid, 0.4g of silver nitrate, 3g of polystyrene sulfonic acid, and 2.8g of boric acid to the above sulfuric acid solution in sequence, and stir for 1 hour to obtain an acidic silicon etching solution.

[0032] Example 9 This embodiment provides a method for preparing an acidic silicon etching solution that effectively controls etching brightness, comprising the following steps: S1. Electronic grade concentrated sulfuric acid is mixed with ultrapure water with a resistivity of 18.2 MΩ·cm to prepare a sulfuric acid solution with a mass concentration of 63%. S2. Add 39g of ammonium bifluoride, 30g of 68% nitric acid, 0.2g of silver nitrate, 3g of polystyrene sulfonic acid, and 2.8g of ammonium tetrafluoroborate to the above sulfuric acid solution in sequence, and stir for 1 hour to obtain an acidic silicon etching solution.

[0033] Example 10 This embodiment provides a method for preparing an acidic silicon etching solution that effectively controls etching brightness, comprising the following steps: S1. Electronic grade concentrated sulfuric acid is mixed with ultrapure water with a resistivity of 18.2 MΩ·cm to prepare a sulfuric acid solution with a mass concentration of 63%. S2. Add 39g of ammonium bifluoride, 30g of 68% nitric acid, 0.2g of silver nitrate, 3g of polystyrene sulfonic acid, and 2.8g of sodium borate tetrahydrate to the above sulfuric acid solution in sequence, and stir for 1 hour to obtain an acidic silicon etching solution.

[0034] Example 11 This embodiment provides a method for preparing an acidic silicon etching solution that effectively controls etching brightness, comprising the following steps: S1. Electronic grade concentrated sulfuric acid is mixed with ultrapure water with a resistivity of 18.2 MΩ·cm to prepare a sulfuric acid solution with a mass concentration of 63%. S2. Add 39g of ammonium bifluoride, 30g of nitric acid with a mass concentration of 68%, 0.2g of silver nitrate, 3g of sodium dodecyl sulfonate, and 2.8g of sodium borate tetrahydrate to the above sulfuric acid solution in sequence, and stir for 1 hour to obtain an acidic silicon etching solution.

[0035] Example 12 This embodiment provides a method for preparing an acidic silicon etching solution that effectively controls etching brightness, comprising the following steps: S1. Electronic grade concentrated sulfuric acid is mixed with ultrapure water with a resistivity of 18.2 MΩ·cm to prepare a sulfuric acid solution with a mass concentration of 63%. S2. Add 39g of ammonium bifluoride, 30g of 68% nitric acid, 0.2g of silver nitrate, and 3g of polystyrene sulfonic acid to the above sulfuric acid solution in sequence, and stir for 1 hour to obtain an acidic silicon etching solution.

[0036] In the above embodiments, ammonium bifluoride is electronic grade with a mass concentration of 40%; nitric acid is electronic grade with a mass concentration of 68%; silver nitrate is electronic grade with a purity of 99.999%; sulfuric acid is electronic grade; and ultrapure water has a resistivity of 18.2 MΩ·cm.

[0037] Comparative Example 1 This comparative example provides a method for preparing an acidic silicon etching solution that effectively controls etching brightness, comprising the following steps: S1. Mix electronic-grade concentrated nitric acid with ultrapure water with a resistivity of 18.2 MΩ·cm to prepare 30g of nitric acid solution with a mass concentration of 68%. S2. Add 39g of ammonium bifluoride to the above nitric acid solution and stir for 1 hour to obtain a traditional acidic silicon etching solution.

[0038] Comparative Example 2 This comparative example provides a method for preparing an acidic silicon etching solution that effectively controls etching brightness, comprising the following steps: S1. Electronic grade concentrated sulfuric acid is mixed with ultrapure water with a resistivity of 18.2 MΩ·cm to prepare a sulfuric acid solution with a mass concentration of 63%. S2. Add 39g of ammonium bifluoride, 30g of 68% nitric acid, 0.2g of silver nitrate, 3g of polystyrene sulfonic acid, and 5g of boric acid to the above sulfuric acid solution in sequence, and stir for 1 hour to obtain an acidic silicon etching solution.

[0039] Comparative Example 3 This comparative example provides a method for preparing an acidic silicon etching solution that effectively controls etching brightness, comprising the following steps: S1. Electronic grade concentrated sulfuric acid was mixed with ultrapure water with a resistivity of 18.2 MΩ·cm to prepare 925.02 g of sulfuric acid solution with a mass concentration of 63%. S2. Add 39g of ammonium bifluoride, 30g of 68% nitric acid, 3g of polystyrene sulfonic acid, and 2.8g of boric acid to the above sulfuric acid solution in sequence, without adding silver nitrate, and stir for 1 hour to obtain an acidic silicon etching solution.

[0040] After the acidic silicon etching solutions for effectively controlling etching brightness in Examples 1-12 and Comparative Examples 1-3 were prepared, the properties of the etching solutions were observed visually. After uniform mixing, the particle size of the etching solutions was analyzed by single-particle inductively coupled plasma mass spectrometry. The surface tension of the etching solutions was measured using a surface tension meter. Then, the PFA bottle containing the etching solution was placed in a constant temperature bath and heated to 38°C. After the internal temperature of the solution stabilized, monocrystalline silicon or polycrystalline silicon wafers were placed in the etching solution and allowed to stand for etching. After etching, the silicon surface was dried by compressed nitrogen gas, and the thickness was measured using a micrometer to calculate the etching amount. After etching and drying, the brightness of the silicon surface was measured using a brightness meter, and the surface morphology of the silicon was observed using an optical microscope and a scanning electron microscope.

[0041] This invention provides several specific etching solution formulations for illustration. In the example formulation, the nitric acid concentration is selected as 68wt%, the sulfuric acid concentration is 63wt%, and the remaining etching solution is supplemented with 63wt% sulfuric acid. Specific implementation examples are shown in Table 1. Table 1 With the etching test conditions remaining essentially consistent except for the differences in the variables under investigation and the comparative examples, the effects of boron-based additives, silver nitrate, surfactants, and ammonium bifluoride on the surface brightness, etching amount, and solution state of the etched silicon were investigated in Examples 1-12 and Comparative Examples 1-3, respectively. The purpose of the above experimental design was to focus on exploring the regulatory effect of boron-based additives on etching brightness, and to further verify the effects of silver nitrate on the oxidation and dissolution process, surfactants on surface uniformity, and ammonium bifluoride on the etching process, thereby demonstrating that the acidic silicon etching solution of this invention can effectively regulate the surface brightness of silicon while maintaining the stability of the etching process.

[0042] The specific experimental results are shown in Table 2. Table 2 Combining the results in Tables 1 and 2, and comparing Examples 12 and 6-10, it is evident that the addition of boron-based additives, such as boric acid, significantly inhibits the rapid progress of the etching process, reduces brightness within the same time frame after etching, and minimizes the brightness difference between etching times using the same solution. This will greatly reduce process errors in actual etching processes, such as... Figure 1 As shown, this demonstrates that boron compounds can indeed control the etching process by complexing F- ions. Further observation of the surface morphology of the etched silicon material, using Examples 12 and 7 as examples, revealed that the addition of boric acid significantly affects the F- ion content. - After the attack of ions is suppressed, it has little effect on the overall morphology, but only changes the density difference in the structural distribution. Figure 2 The image shows the morphology of the silicon material after etching in Example 12. Figure 3 The image shows the surface morphology of the silicon material after etching in Example 7. Furthermore, a comparison of Examples 1-3 reveals that the boric acid content significantly affects the etching brightness; low boric acid content results in high brightness, and high boric acid content in low brightness. Therefore, in process engineering, controlling etching brightness variations cannot be achieved solely by adjusting fluoride content; it can also be done by changing the content of boron-based compound additives. Moreover, the comparison of added content shows that boron-based compounds are more sensitive and effective in controlling brightness. In addition, the results of these examples demonstrate that changes in the content and composition of surfactants do not significantly affect etching brightness; in practical operation, they are only used to improve surface uniformity and prevent discoloration. Changes in silver nitrate content, as in Example 8, can increase the etching amount to a certain extent, thus affecting etching brightness to some extent. However, the degree of influence is far less than that of adding boron-based compounds.

[0043] The etching rate of Comparative Example 1 was too fast, with an etching depth of 92 μm in 10 minutes, far exceeding the 18-70 μm range of the Examples. Regarding brightness, Comparative Example 1 achieved a brightness of 285 after 10 minutes, with extremely wide brightness variations, indicating uncontrolled reaction and poor process stability. The solution was turbid after etching, indicating that the reaction products could not be stably dispersed. This fully demonstrates the indispensable synergistic effect of sulfuric acid as the base acid, boron compounds as corrosion inhibitors, and surfactants as dispersants in this invention.

[0044] The etching rate of Comparative Example 2 was too low, with an etching depth of only 8 μm in 10 minutes and almost no change in brightness. Although the brightness stability was extremely high, the etching efficiency was severely insufficient and could not meet the production capacity requirements of industrial production. The solution showed precipitation after etching, indicating that excessive boric acid led to an over-complexation reaction, and some boric acid failed to dissolve completely or reacted with other components to produce precipitation.

[0045] Comparative Example 3 achieved a brightness of 76 and an etching depth of 42 μm after 10 minutes, both higher than Example 7 (brightness 30, etching depth 18 μm). This indicates that the addition of silver nitrate does indeed promote the hole injection effect and accelerate the oxidation and dissolution reaction of silicon. However, the brightness variation range of Comparative Example 3 is greater than that of Example 7, indicating that the stability of brightness control decreases when silver nitrate is absent. This is because silver nitrate and boron compounds have a synergistic effect; silver nitrate provides the oxidation driving force, while boron compounds control the reaction rate. Only through their combined action can both efficient and stable etching effects be achieved.

[0046] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. An acidic silicon etching solution for effectively controlling etching brightness, characterized in that, By weight percentage, its raw materials include: Ammonium bifluoride: 2-7%; Nitric acid: 1.5-8.5%; Silver nitrate: 0.01-0.1%; Surfactant: 0.1-0.5%; Boron compound additives: 0.05-0.4%; Sulfuric acid: Balance.

2. The acidic silicon etching solution for effectively controlling etching brightness according to claim 1, characterized in that, The surfactant is selected from at least one of p-nitrobenzenesulfonic acid, 3-nitrobenzenesulfonic acid, p-toluenesulfonic acid, polystyrenesulfonic acid, sodium dodecylbenzenesulfonate, and sodium dodecyl sulfonate.

3. The acidic silicon etching solution for effectively controlling etching brightness according to claim 2, characterized in that, The surfactant is polystyrene sulfonic acid.

4. The acidic silicon etching solution for effectively controlling etching brightness according to claim 1, characterized in that, The boron compound additive is selected from at least one of boric acid, ammonium tetrafluoroborate, sodium octaborate tetrahydrate, and sodium borate tetrahydrate.

5. The acidic silicon etching solution for effectively controlling etching brightness according to claim 1, characterized in that, The boron compound additive is boric acid.

6. The acidic silicon etching solution for effectively controlling etching brightness according to claim 1, characterized in that, The mass concentration of the hydrogen fluoride is 38-42%; the mass concentration of the nitric acid is 68-70%.

7. The acidic silicon etching solution for effectively controlling etching brightness according to claim 1, characterized in that, The sulfuric acid has a mass concentration of 63-68%.

8. The acidic silicon etching solution for effectively controlling etching brightness according to claim 1, characterized in that, The preparation method of the acidic silicon etching solution that effectively controls the etching brightness includes the following steps: S1, mixing sulfuric acid with ultrapure water to obtain a sulfuric acid solution; S2, adding ammonium bifluoride, nitric acid, silver nitrate, surfactant and boron compound additives to the sulfuric acid solution in sequence, and stirring.

9. The acidic silicon etching solution for effectively controlling etching brightness according to claim 8, characterized in that, In step S1, the resistivity of the ultrapure water is 18.2 MΩ·cm.

10. The acidic silicon etching solution for effectively controlling etching brightness according to claim 8, characterized in that, In step S2, the stirring time is 1-2 hours.

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