Silicon wafer etching method and silicon wafer etching equipment
By designing a dual-tank etching system, the problem of frequent solution replacement in silicon wafer etching methods is solved by using the first tank for preliminary etching and the second tank for dilution. This achieves low-cost and high-efficiency etching results, reducing chemical consumption and waste liquid treatment costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- XIAN ESWIN MATERIAL TECHNOLOGY CO LTD
- Filing Date
- 2026-01-21
- Publication Date
- 2026-04-14
AI Technical Summary
Existing silicon wafer etching methods require frequent replacement of etching solutions, resulting in high chemical consumption and high waste liquid treatment costs.
A dual-tank etching system is adopted. The first tank is used for preliminary etching, and the second tank is used for the remaining etching. The initial volume of the etching solution in the first tank is smaller than that in the second tank. The solution in the first tank is replaced periodically or in real time to reduce the concentration of metal ions. The solution in the second tank is diluted in large volume to maintain a low concentration and extend its service life.
It reduces chemical consumption and waste liquid treatment costs, improves etching quality stability and production efficiency, and reduces production risks.
Smart Images
Figure CN121865865A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of semiconductor product manufacturing technology, and in particular to a silicon wafer etching method and silicon wafer etching equipment. Background Technology
[0002] Large-size silicon wafers are typically produced from single-crystal silicon rods drawn using the Czochra Lski (CZ) method. Specifically, the CZ method involves placing high-purity polycrystalline silicon raw material into a quartz crucible and heating it to melt, forming a silicon melt. A seed crystal is then lowered into the silicon melt. Single-crystal silicon rods are produced through processes such as temperature testing, crystal pulling, necking, shoulder formation, constant-diameter growth, and finishing. These rods are then cut, ground, polished, and cleaned to obtain usable silicon wafers.
[0003] In the production and testing of silicon wafers, increasingly higher requirements are placed on circuit integration, meaning smaller linewidths, more integrated components, and reduced power consumption. Therefore, the content of metal contaminants in the single-crystal silicon wafer used as the substrate must be strictly controlled. Metal ion contamination can lead to varying degrees of defects in semiconductor devices. For example, alkali metal contamination such as Na, K, Ca, Mg, and Ba can reduce the breakdown voltage of components; transition metal or heavy metal contamination such as Fe, Cr, Ni, Cu, Mn, and Pb can shorten the lifespan of components or increase dark current during operation, ultimately causing complete device failure. Transition metals not only contaminate the silicon wafer surface but also, due to their high solid solubility and migration rate, can diffuse into the silicon wafer body in a short time. Some transition metals are slow-diffusing metals in silicon, such as Fe, Mn, V, Ti, Cr, and Cs. Most slow-diffusing metals can diffuse to the near-surface layer of the silicon wafer, thus requiring etching to remove this layer. Etching allows for precise etching of the silicon wafer surface to achieve processing or testing purposes.
[0004] However, current etching methods require frequent solution changes, resulting in high chemical consumption and high waste liquid treatment costs. Summary of the Invention
[0005] To address the aforementioned technical problems, this disclosure provides a silicon wafer etching method and a silicon wafer etching apparatus, which solves the problem of frequent replacement of etching solutions, resulting in excessive chemical consumption and high costs.
[0006] To achieve the above objectives, the technical solution adopted in this disclosure is: a silicon wafer etching method, comprising the following steps:
[0007] The silicon wafer is immersed in the etching solution in the first etching tank for preliminary etching;
[0008] The silicon wafer that has undergone preliminary etching is immersed in the etching solution in the second etching tank to perform the remaining etching until the target etching amount of the silicon wafer is reached.
[0009] The etching solution in the first etching tank is the same as the etching solution in the second etching tank, and the initial capacity of the etching solution in the first etching tank is less than the initial capacity of the etching solution in the second etching tank.
[0010] Optionally, the initial capacity of the etching solution in the first etching tank is 1 / 5 to 2 / 5 of the initial capacity of the etching solution in the second etching tank.
[0011] Optionally, the initial etching amount is 1 / 3 to 3 / 4 of the target etching amount.
[0012] Optionally, immersing the silicon wafer in the etching solution in the first etching tank for preliminary etching includes: during the preliminary etching process, periodically replacing the etching solution in the first etching tank at preset times.
[0013] Optionally, immersing the silicon wafer in the etching solution in the first etching tank for preliminary etching includes: during the preliminary etching process, replacing the etching solution in the first etching tank when the concentration of metal ions in the etching solution in the first etching tank exceeds a preset value.
[0014] Optionally, the etching solution is a KOH solution.
[0015] Optionally, the concentration of the etching solution in both the first and second etching tanks is 30-45 wt%.
[0016] Optionally, the first etching tank and the second etching tank have the same temperature environment.
[0017] Optionally, after immersing the pre-etched silicon wafer in the etching solution in the second etching tank to perform the remaining etching until the target etching amount is reached, the method further includes: cleaning and drying the silicon wafer that has achieved the target etching amount.
[0018] This disclosure also provides an etching apparatus for implementing the above-described silicon wafer etching method, characterized in that the etching apparatus comprises:
[0019] The first etching tank is used to hold the etching solution for the initial etching of the silicon wafer;
[0020] The second etching tank is used to contain etching solution to perform the remaining etching on the silicon wafer that has undergone preliminary etching, until the target etching amount of the silicon wafer is reached;
[0021] Wherein, the initial capacity of the etching solution in the first etching tank is less than the initial capacity of the etching solution in the second etching tank.
[0022] The beneficial effects of this invention are as follows: In the silicon wafer etching method provided in this disclosure, the silicon wafer undergoes preliminary etching in a first etching tank, and then the remaining etching is performed in a second etching tank. The second etching tank receives the silicon wafer that has been etched in the first etching tank. Because the etching solution in the first etching tank carries away some of the metal ions and other impurities that need to be etched, the concentration of metal ions and other impurities in the etching solution entering the second etching tank is reduced. Furthermore, due to the large initial volume of the etching solution in the second etching tank, even if a small amount of new contaminants enters, they will be rapidly diluted by the large volume of solution, maintaining their concentration at an extremely low level that does not affect the etching quality. This greatly slows down the degradation rate of the solution performance in the second etching tank, allowing for long-term use. Attached Figure Description
[0023] Figure 1 A schematic flowchart illustrating the silicon wafer etching method in the embodiments of this disclosure;
[0024] Figure 2 This is a schematic flowchart illustrating the silicon wafer etching method in an embodiment of this disclosure. Detailed Implementation
[0025] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.
[0026] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an,” “a,” or “the,” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “including,” “comprising,” or “containing,” and similar terms mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. The terms “connected,” “linked,” or similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms “upper,” “lower,” “left,” and “right,” etc., are used only to indicate relative positional relationships, and these relative positional relationships may change accordingly when the absolute position of the described objects changes.
[0027] refer to Figure 1 This embodiment provides a silicon wafer etching method, including the following steps:
[0028] S1: Immerse the silicon wafer in the etching solution in the first etching tank for preliminary etching;
[0029] S2: Immerse the silicon wafer that has undergone preliminary etching into the etching solution in the second etching tank to perform the remaining etching until the target etching amount of the silicon wafer is reached;
[0030] The etching solution in the first etching tank is the same as the etching solution in the second etching tank, and the initial capacity of the etching solution in the first etching tank is less than the initial capacity of the etching solution in the second etching tank.
[0031] Current etching methods involve etching only in an etching tank containing an etching solution. In order to control the concentration of metal ions in the solution and ensure product quality, frequent and complete solution changes are necessary, resulting in high chemical consumption and high waste liquid treatment costs.
[0032] The silicon wafer etching method provided in this embodiment differs from traditional etching methods that only have one etching tank. This embodiment adds a first etching tank to the original etching tank, allowing for initial etching of the silicon wafer using the first etching tank, followed by the second etching tank for the remaining etching. In other words, the second etching tank receives the silicon wafer that has already been etched by the first etching tank. Because the etching solution in the first etching tank carries away some of the metal ions and other impurities to be etched, the concentration of these impurities in the etching solution entering the second etching tank is reduced. Furthermore, due to the large volume of the second etching tank (i.e., the large capacity of the etching solution within it), even if a small amount of new contaminants enters, they will be rapidly diluted by the large volume of solution, maintaining their concentration at a very low level that does not affect the etching quality. This significantly slows down the degradation rate of the solution performance in the second etching tank, allowing for long-term use. Therefore, compared to traditional etching methods with only one etching tank, the etching solution in the second etching tank has a longer lifespan.
[0033] Furthermore, since the initial capacity of the etching solution in the first etching tank is less than the initial capacity of the etching solution in the second etching tank, and the capacity of the etching solution in the first etching tank is less than the capacity of the etching solution in the second etching tank, some metal ions can be removed by replacing the etching solution in the first etching tank multiple times. Moreover, the cost of replacing the etching solution in the first etching tank is much lower than that of replacing the etching solution in the second etching tank.
[0034] In an exemplary embodiment, the initial volume of the etching solution in the first etching tank is 1 / 5 to 2 / 5 of the initial volume of the etching solution in the second etching tank.
[0035] The initial capacity of the etching solution in the first etching tank and the initial capacity of the etching solution in the second etching tank can be set according to actual needs. For example, the initial capacity of the etching solution in the first etching tank is 20%, 30%, or 40% of the initial capacity of the etching solution in the second etching tank, but is not limited to these values.
[0036] In some embodiments, the initial capacity of the etching solution in the second etching tank is 100 L, and the initial capacity of the etching solution in the first etching tank is 20-30 L. For example, the initial capacity of the etching solution in the first etching tank can be 20 L, 25 L, or 30 L, but is not limited thereto.
[0037] Assume the initial volume of the etching solution in the second etching tank is V, and the initial volume of the etching solution in the first etching tank is kV (k < 1, preferably k = 1 / 5 to 2 / 5). When the etching solution needs to be replaced, the cost of replacing the etching solution in the first etching tank with the smaller initial volume is only k times the cost of replacing the etching solution in the second etching tank with the larger initial volume. The initial etching stage is generally the stage with the most severe contamination. By frequently and cost-effectively replacing the etching solution in the first etching tank to maintain high-quality etching, while replacing the high-cost etching solution in the second etching tank with extremely infrequent replacement, the total chemical consumption and wastewater treatment cost per unit output are minimized.
[0038] Under the aforementioned ratio, the first etching tank can hold a sufficient amount of fresh etching solution to ensure the initial etching depth and uniformity, and its relatively small volume ensures that high-concentration contaminants can be promptly removed from the system at a reasonable solution replacement frequency (e.g., every 4-8 hours). The larger initial volume of etching solution in the second etching tank (2.5 to 5 times the initial volume of the etching solution in the first etching tank) provides sufficient volume for further dilution of trace contaminants, keeping their concentration below the threshold affecting etching quality for an extended period.
[0039] Because the initial volume of the etching solution in the first etching tank is small, maintenance operations such as cleaning, leak detection, and component replacement are simpler and less time-consuming. As the front end of the process, if a sudden and severe contamination is introduced due to misoperation or silicon wafer abnormalities in the first etching tank, its impact is limited to a small tank that accounts for only 20% to 40% of the total capacity. It can be restored by quickly changing the solution, avoiding contamination of the second etching tank, which contains a large volume of etching solution, thus greatly reducing production risks and the scope of quality accidents.
[0040] In an exemplary embodiment, in the step of "immersing the silicon wafer in the etching solution in the first etching tank for preliminary etching", the amount of preliminary etching is 1 / 3 to 3 / 4 of the target etching amount.
[0041] The etching amount in the initial etching can be set according to actual needs. For example, the etching amount in the initial etching can be 1 / 3, 2 / 3, or 3 / 4 of the target etching amount, but it is not limited to this.
[0042] In this embodiment, the initial etching amount is 1 / 3 to 3 / 4 of the target etching amount, so that most of the metal ions and other impurities that need to be etched in the silicon wafer are left in the first etching tank, reducing the amount of impurities entering the second etching tank, thereby extending the service life of the etching solution in the second etching tank.
[0043] For example, the etching time can be set so that the silicon wafer reaches a preset etching amount in the initial etching step.
[0044] Freshly prepared etching solutions can be used to accurately determine the relationship between etching depth and time under standard process conditions (such as specific concentration, temperature, and stirring speed) through experiments, thereby obtaining the etching rate.
[0045] For example, the etching thickness of the silicon wafer can be measured periodically or in real time by measuring the structure, thereby determining whether the etching amount of the silicon wafer in the initial etching step meets the preset standard.
[0046] The measurement structure may include an image acquisition unit, which acquires and analyzes the morphological information of the silicon wafer to determine the etching amount of the silicon wafer.
[0047] The measurement structure may also include an optical sensor to measure the thickness of the silicon wafer to determine the amount of etching on the silicon wafer.
[0048] In an exemplary embodiment, in the step of "immersing the silicon wafer in the etching solution in the first etching tank for preliminary etching", the etching solution in the first etching tank is replaced periodically according to a preset time during the preliminary etching process.
[0049] It should be noted that the replacement time of the etching solution in the first etching tank can be set according to the actual situation.
[0050] In this embodiment, by periodically replacing the etching solution, the etching solution in the first etching tank is ensured to remain within the high-performance window, providing a stable process environment for the initial etching stage. This prevents severe compositional imbalances (such as silicate supersaturation precipitation) caused by overuse of the solution. These precipitates can adhere to the tank walls and heaters, are difficult to clean, and can damage the equipment over time. Furthermore, by ensuring the efficient contaminant interception function of the first etching tank, the second etching tank is further protected, resulting in a synergistic reduction in maintenance costs.
[0051] In an exemplary embodiment, in the step of "immersing the silicon wafer in the etching solution in the first etching tank for preliminary etching", during the preliminary etching process, the etching solution in the first etching tank is replaced when the concentration of metal ions in the etching solution in the first etching tank exceeds a preset value.
[0052] For example, the silicon wafer etching method provided in this embodiment may only include replacing the etching solution in the first etching tank periodically at a preset time during the initial etching process, or it may only include replacing the etching solution in the first etching tank when the metal ion concentration in the etching solution in the first etching tank exceeds a preset value during the initial etching process.
[0053] The content of impurities such as metal ions varies in silicon wafers. Simply replacing the etching solution in the first etching tank periodically risks the impurity content in the etching solution exceeding a preset threshold, thus affecting the etching quality. In this embodiment, the concentration of metal ions in the etching solution in the first etching tank can be acquired periodically or in real time to ensure the performance of the etching solution in the first etching tank.
[0054] Furthermore, in some embodiments, the silicon wafer etching method includes, in addition to the step of periodically replacing the etching solution in the first etching tank at preset times during the initial etching process, real-time or timed detection of the concentration of metal ions in the etching solution in the first etching tank. If the concentration of metal ions in the etching solution in the first etching tank exceeds a preset value, the etching solution in the first etching tank needs to be replaced even if the replacement time has not been reached, in order to ensure etching quality.
[0055] It should be noted that when both the etching solution in the first etching tank is replaced periodically and the concentration of metal ions in the etching solution in the first etching tank is detected in real time or at regular intervals, if the concentration of metal ions in the etching solution in the first etching tank is detected at regular intervals, the time for detecting the concentration of metal ions in the etching solution in the first etching tank should be less than the time for replacing the etching solution in the first etching tank periodically.
[0056] In an exemplary embodiment, the etching solution is a KOH solution.
[0057] In an exemplary embodiment, the concentration of the etching solution in both the first etching tank and the second etching tank is 30-45 wt%.
[0058] The etching rate of silicon by KOH solution exhibits a non-monotonic variation with concentration. At a constant temperature (e.g., 80°C), the etching rate typically peaks in the concentration range of 30-45 wt%. Below this range, the concentration of OH⁻ ions in the solution is insufficient, resulting in a slower etching rate; above this range, the solution viscosity increases significantly, inhibiting the diffusion and mass transfer of reactants (OH⁻) and products (silicates), thus leading to a decrease in the etching rate. Therefore, selecting a concentration of 30-45 wt% is fundamental to ensuring high production efficiency.
[0059] Since the etching solution concentrations in the first and second etching tanks are consistent, the silicon wafer will not experience etching kinetic shocks caused by sudden changes in solution concentration when it is transferred from the first etching tank to the second etching tank, thus avoiding potential defects.
[0060] For example, after the silicon wafer undergoes initial etching in the first etching tank, it immediately enters the second etching tank for further etching. This means there are no other processes between the first and second etching tanks, including a cleaning process, ensuring consistent etching conditions and preventing uncontrollable etching amounts due to inconsistent parameters. For instance, if the surface of the silicon wafer after initial etching is coated with etching solution from the first etching tank, cleaning it before entering the second etching tank would dilute the etching solution on the wafer surface. This could introduce more impurities in other processes, affecting the stability of subsequent etching processes.
[0061] In an exemplary embodiment, the first etching tank and the second etching tank have the same temperature environment.
[0062] The temperature of the first etching tank and the second etching tank is 60-90 degrees. For example, the temperature of the first etching tank and the second etching tank can be 60 degrees, 70 degrees, 80 degrees or 90 degrees, but is not limited to this.
[0063] The first and second etching tanks have the same temperature environment to avoid uneven etching caused by inconsistent temperatures.
[0064] refer to Figure 2 In an exemplary embodiment, after immersing the pre-etched silicon wafer in the etching solution in the second etching tank to perform the remaining etching until the target etching amount is reached, the method further includes: S3: cleaning and drying the silicon wafer that has completed the target etching amount.
[0065] In the cleaning process, ultrapure water can be used as the cleaning solution, but it is not a limitation.
[0066] In the drying process, inert high-pressure clean gas can be used to blow the surface of the silicon wafer to dry it.
[0067] This disclosure also provides an etching apparatus for implementing the above-described silicon wafer etching method, characterized in that the etching apparatus comprises:
[0068] The first etching tank is used to contain the etching solution for the initial etching of the silicon wafer;
[0069] The second etching tank is used to contain the etching solution to perform the remaining etching on the silicon wafer that has undergone preliminary etching, until the target etching amount of the silicon wafer is reached.
[0070] Wherein, the initial capacity of the etching solution in the first etching tank is less than the initial capacity of the etching solution in the second etching tank.
[0071] For example, the initial capacity of the etching solution in the first etching tank is 1 / 5 to 2 / 5 of the initial capacity of the etching solution in the second etching tank, but is not limited thereto.
[0072] In some embodiments, the initial volume of the etching solution in the first etching tank is 20-30 L, and the initial volume of the etching solution in the second etching tank is 100 L.
[0073] Compared to traditional etching methods with only one etching tank, this embodiment adds a first etching tank to the original etching tank. This allows for initial etching of the silicon wafer using the first etching tank, followed by the remaining etching using the second etching tank. In other words, the second etching tank receives the silicon wafer etched by the first etching tank. Because the etching solution in the first etching tank carries away some metal ions and other impurities to be etched, the concentration of these impurities in the etching solution entering the second etching tank is reduced. Furthermore, due to the large initial volume of the etching solution in the second etching tank, even if a small amount of new contaminants enters, they will be rapidly diluted by the large volume of solution, maintaining their concentration at a very low level that does not affect etching quality. This significantly slows down the degradation rate of the solution performance in the second etching tank, allowing for long-term use. Therefore, compared to traditional etching methods with only one etching tank, the etching solution in the second etching tank has a longer lifespan.
[0074] Furthermore, since the initial capacity of the etching solution in the first etching tank is smaller than that in the second etching tank, some metal ions can be removed by repeatedly replacing the etching solution in the first etching tank. Moreover, the cost of replacing the etching solution in the first etching tank is much lower than that of replacing the etching solution in the second etching tank.
[0075] In this embodiment, the first etching tank and the second etching tank cooperate with each other. The silicon wafer undergoes initial etching in the first etching tank, and then the remaining etching is performed in the second etching tank. The first etching tank undergoes multiple solution changes to remove most of the metal ions, thereby enabling the second etching tank to operate stably for a long period of time, achieving cost reduction and stable product quality. The etching rate and uniformity of the second etching tank become more controllable due to the clean and stable etching solution, which is conducive to achieving stable etching and ensuring consistency between product batches. The etching solution in the second etching tank always maintains a low metal ion concentration, fundamentally reducing the risk of metal contamination on the product surface and improving product yield and stability.
[0076] For example, the etching solution in the first etching tank is the same as the etching solution in the second etching tank, that is, the composition of the etching solution in the first etching tank is the same as the composition of the etching solution in the second etching tank. In some embodiments, both the etching solution in the first etching tank and the etching solution in the second etching tank are KOH solutions, and the concentrations of the etching solutions in the first etching tank and the second etching tank are both 30-45 wt%, for example, 30 wt%, 40 wt%, and 45 wt%.
[0077] In an exemplary embodiment, the silicon wafer etching apparatus further includes a cleaning structure and a drying structure.
[0078] The cleaning structure may include an ultrapure water supply structure and a nozzle for spraying ultrapure water.
[0079] The drying structure may include an inert high-pressure clean gas supply structure and an air knife for purging silicon wafers.
[0080] In an exemplary embodiment, the silicon wafer etching apparatus further includes a first detection structure for detecting the concentration of metal ions in the etching solution in the first etching tank, and a second detection structure for detecting the concentration of metal ions in the etching solution in the second etching tank.
[0081] Furthermore, embodiments of this disclosure provide an electronic device including a memory, a processor, and one or more programs stored in the memory and executable on the processor, wherein when the one or more programs are executed by the processor, the electronic device performs the silicon wafer etching method as described above.
[0082] In one embodiment, this disclosure also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps in the above method embodiments.
[0083] The aforementioned computer-readable storage medium, since the computer program stored in its memory is executed by the processor to implement the steps in the above-described method embodiments, can similarly bring about the beneficial effects of the above-described silicon wafer placement and removal method, which will not be elaborated here.
[0084] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, or optical storage, etc. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.
[0085] The following points need to be explained:
[0086] (1) The accompanying drawings of the embodiments of this disclosure only involve the structures involved in the embodiments of this disclosure. Other structures can be referred to the general design.
[0087] (2) For clarity, the thickness of layers or regions is enlarged or reduced in the drawings used to describe embodiments of the present disclosure, i.e., these drawings are not drawn to scale. It will be understood that when an element such as a layer, film, region or substrate is referred to as being “above” or “below” another element, the element may be “directly” located “above” or “below” the other element or there may be intermediate elements.
[0088] (3) Where there is no conflict, the embodiments of this disclosure and the features in the embodiments can be combined with each other to obtain new embodiments.
[0089] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.
Claims
1. A silicon wafer etching method, characterized in that, Includes the following steps: The silicon wafer is immersed in the etching solution in the first etching tank for preliminary etching; The silicon wafer that has undergone preliminary etching is immersed in the etching solution in the second etching tank to perform the remaining etching until the target etching amount of the silicon wafer is reached. The etching solution in the first etching tank is the same as the etching solution in the second etching tank, and the initial capacity of the etching solution in the first etching tank is less than the initial capacity of the etching solution in the second etching tank.
2. The silicon wafer etching method according to claim 1, characterized in that, The initial capacity of the etching solution in the first etching tank is 1 / 5 to 2 / 5 of the initial capacity of the etching solution in the second etching tank.
3. The silicon wafer etching method according to claim 1, characterized in that, The initial etching amount is 1 / 3 to 3 / 4 of the target etching amount.
4. The silicon wafer etching method according to claim 1, characterized in that, The step of immersing the silicon wafer in the etching solution within the first etching tank for preliminary etching includes: During the initial etching process, the etching solution in the first etching tank is replaced periodically according to a preset time.
5. The silicon wafer etching method according to claim 1 or 4, characterized in that, The step of immersing the silicon wafer in the etching solution within the first etching tank for preliminary etching includes: During the initial etching process, the etching solution in the first etching tank is replaced when the concentration of metal ions in the etching solution in the first etching tank exceeds a preset value.
6. The silicon wafer etching method according to claim 1, characterized in that, The etching solution is a KOH solution.
7. The silicon wafer etching method according to claim 6, characterized in that, The concentration of the etching solution in both the first and second etching tanks is 30-45 wt.
8. The silicon wafer etching method according to claim 1, characterized in that, The first etching tank and the second etching tank have the same temperature environment.
9. The silicon wafer etching method according to claim 1, characterized in that, After immersing the pre-etched silicon wafer in the etching solution within the second etching tank to perform the remaining etching until the target etching amount is reached, the method further includes: The silicon wafer that has achieved the target etching amount is then cleaned and dried.
10. An etching apparatus for implementing the silicon wafer etching method according to any one of claims 1-9, characterized in that, The etching equipment includes: The first etching tank is used to contain the etching solution for the initial etching of the silicon wafer; The second etching tank is used to contain the etching solution to perform the remaining etching on the silicon wafer that has undergone preliminary etching, until the target etching amount of the silicon wafer is reached; Wherein, the initial capacity of the etching solution in the first etching tank is less than the initial capacity of the etching solution in the second etching tank.