Method and apparatus for wet etching of silicon wafers

Abstract

The application discloses a wet etching method and device for silicon wafer, which comprises the following steps: immersing the silicon wafer with a metal film layer on the surface into a metal etching solution; waiting for a preset reaction time, taking the reacted silicon wafer out of the metal etching solution; repeating the steps of immersing the reacted silicon wafer into the metal etching solution and waiting for a preset reaction time until the etching of the metal film layer on the surface of the silicon wafer is completed. Through the above steps, the silicon wafer is repeatedly thrown up and down, so that the speed of each silicon wafer is the same, and compared with the rotating silicon wafer, the speed of the silicon wafer close to the rotating center is small, and the speed of the silicon wafer far from the rotating center is large, so that the etching uniformity of the silicon wafer is ensured, the silicon wafer is prevented from being damaged due to the excessively large speed, the residual product on the surface of the silicon wafer is taken away by taking the silicon wafer out of the liquid level, the product is prevented from adhering to the surface of the silicon wafer and hindering the etching reaction, and the reaction efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor, in particular to a wet etching method and device of silicon wafer. BACKGROUND

[0002] Metal wet etching is a kind of etching method, which is a technology of soaking etching material in etching liquid. However, the reaction product generated during etching will adhere to the surface of the metal, which will prevent the further reaction and reduce the reaction efficiency, thus being not conducive to the completion of metal wet etching.

[0003] The existing metal wet etching process solves the above problems by setting a rotating device in the metal etching liquid reaction tank to make the silicon wafer rotate in the metal etching liquid. However, the rotating method cannot well remove the reaction product on the surface of the silicon wafer, and there are still a lot of reaction products adhering to the surface of the silicon wafer, which prevents the further reaction, resulting in poor etching effect and incomplete etching. Moreover, when the rotating speed is too large, the silicon wafer far from the rotating device will have a very large speed, which is easy to be separated from the flower basket frame loaded with the silicon wafer, thus causing damage to the silicon wafer. SUMMARY

[0004] The present application aims to provide a wet etching method and device of silicon wafer, which can prevent the damage to the silicon wafer, improve the reaction efficiency and ensure the uniformity of silicon wafer etching.

[0005] The present application discloses a wet etching method of silicon wafer, which comprises the following steps: immersing a silicon wafer with a metal film layer formed on the surface into a metal etching liquid; waiting for a first preset time for reaction, and then taking the reacted silicon wafer out of the metal etching liquid; repeating the steps of immersing the reacted silicon wafer into the metal etching liquid and waiting for a first preset time for reaction, and then taking the reacted silicon wafer out of the metal etching liquid, until the etching of the metal film layer on the surface of the silicon wafer is completed.

[0006] Optionally, in the step of waiting for a first preset time for reaction and then taking the reacted silicon wafer out of the metal etching liquid, the reacted silicon wafer is placed for 0.2-0.5s after being taken out of the metal etching liquid; in the step of repeating the steps of immersing the reacted silicon wafer into the metal etching liquid and waiting for a first preset time for reaction, and then taking the reacted silicon wafer out of the metal etching liquid, until the etching of the metal film layer on the surface of the silicon wafer is completed, the reacted silicon wafer is placed for 0.2-0.5s after being taken out of the metal etching liquid.

[0007] Optionally, the surface of the reacted silicon wafer is sprayed with the metal etching liquid during the placing process.

[0008] Optionally, after the reacted silicon wafer is placed for 0.2-0.5s, the placed silicon wafer is further rotated.

[0009] Optionally, in the step of immersing the silicon wafer with the metal film layer on the surface into the metal etching solution, the silicon wafer is immersed into the metal etching solution along a vertical direction; in the step of waiting for a preset reaction time and taking the reacted silicon wafer out of the metal etching solution, the silicon wafer is taken out of the metal etching solution along a vertical direction.

[0010] Optionally, in the step of repeatedly immersing the reacted silicon wafer into the metal etching solution, waiting for a first preset reaction time, taking the reacted silicon wafer out of the metal etching solution, and placing the silicon wafer for a second preset time until the etching of the metal film layer on the surface of the silicon wafer is completed, the step includes repeatedly immersing the reacted silicon wafer into the metal etching solution, waiting for a first preset reaction time, taking the reacted silicon wafer out of the metal etching solution, and placing the silicon wafer for a second preset time; wherein the second preset time gradually decreases as the number of repetitions increases.

[0011] The application further discloses a wet etching device for a silicon wafer, which is used for the wet etching method for the silicon wafer, and the wet etching device for the silicon wafer includes a reaction device for placing a metal etching solution, a fixing device for fixing a silicon wafer, and a driving device cooperating with the fixing device and the reaction device for immersing or taking the silicon wafer in the fixing device into or out of the metal etching solution in the reaction device.

[0012] Optionally, the reaction device includes a metal etching solution reaction tank, the driving device includes a motor and a track, the fixing device includes a flower basket frame, the metal etching solution reaction tank is provided with the metal etching solution, the flower basket frame is provided with the silicon wafer, one end of the track is connected to an output shaft of the motor, and the other end of the track is connected to the flower basket frame, and the motor controls the flower basket frame to immerse into or take out of the metal etching solution reaction tank through the track.

[0013] Optionally, the wet etching device for the silicon wafer further includes a turnover device, the turnover device is connected to the flower basket frame, and the turnover device controls the flower basket frame to turn over.

[0014] Optionally, the wet etching device for the silicon wafer further includes a spraying device, the spraying device is arranged outside the reaction device and connected to the reaction device, and the spraying device sprays the metal etching solution on the surface of the silicon wafer after the silicon wafer is taken out of the metal etching solution.

[0015] Compared with the scheme of setting a rotating device in the metal etching liquid reaction tank so that the silicon wafer rotates in the metal etching liquid, the application controls the repeated immersion and lifting of the silicon wafer, wherein the immersion means that the silicon wafer is completely immersed in the metal etching liquid, and the lifting means that the silicon wafer is completely lifted out of the metal etching liquid. When the silicon wafer is immersed in the metal etching liquid, the metal film layer on the surface of the silicon wafer reacts with the metal etching liquid to generate a product, and the product adheres to the outer surface of the silicon wafer, preventing the metal film layer on the surface of the silicon wafer from further reacting with the metal etching liquid. When the silicon wafer is lifted out of the metal etching liquid, the residual metal etching liquid on the surface of the silicon wafer flows downward along the surface of the silicon wafer, thereby carrying away the product adhering to the outer surface of the silicon wafer, and thereby achieving the effects of improving the reaction rate and ensuring the uniformity of the etching of the silicon wafer. BRIEF DESCRIPTION OF DRAWINGS

[0016] The accompanying drawings, which are included to provide a further understanding of the embodiments of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application. It is apparent that the accompanying drawings are only some embodiments of the application, and other drawings can be obtained by those of ordinary skill in the art without creative labor based on the accompanying drawings. In the drawings:

[0017] Figure 1 is a first wet etching method flowchart of a silicon wafer according to an embodiment of the application;

[0018] Figure 2 is a second wet etching method flowchart of a silicon wafer according to an embodiment of the application;

[0019] Figure 3 is a third wet etching method flowchart of a silicon wafer according to an embodiment of the application;

[0020] Figure 4 is a schematic diagram of a wet etching device for a silicon wafer according to an embodiment of the application.

[0021] In the drawings, 10 is a wet etching device, 100 is a reaction device, 200 is a fixing device, 300 is a driving device, 400 is a turnover device, 500 is a spraying device, and 600 is a rotor device. DETAILED DESCRIPTION

[0022] It should be understood that the terms used herein, the specific structures and functional details disclosed, are only for the purpose of describing specific embodiments, and are representative, but the application can be embodied in many alternative forms, and should not be interpreted as being limited to the embodiments described herein.

[0023] The application will be described in detail below with reference to the accompanying drawings and optional embodiments.

[0024] Figure 1 Figure 1 is a flow chart of a silicon wafer wet etching method according to an embodiment of the application, as shown, a silicon wafer wet etching method is disclosed, comprising the steps of: Figure 1

[0025] S1: immersing a silicon wafer with a metal film layer on the surface into a metal etching solution;

[0026] S2: waiting for a first preset time, and taking the reacted silicon wafer out of the metal etching solution;

[0027] S3: repeating the steps of immersing the reacted silicon wafer into the metal etching solution and waiting for a first preset time, and taking the reacted silicon wafer out of the metal etching solution, until the metal film layer on the surface of the silicon wafer is etched completely.

[0028] The basic principle of wet etching is to use the chemical reaction of the metal etching solution on the metal film to remove the film or form a pattern. For example, using the metal etching solution HNO3 (nitric acid) to etch the TiNiAg (titanium nickel silver) alloy on the surface of the silicon wafer. In the reaction, NiAg reacts with HNO3 to generate nitrate and nitrogen oxide gas, and the chemical equation is Ni+HNO3=Ni(NO3)2+2NO2+2H2O and 3Ag+4HNO3=3AgNO3+NO+2H2O. The byproduct nitrate will adhere to the surface of TiNiAg, blocking the further reaction of nitric acid and TiNiAg, resulting in poor corrosion effect of the metal on the surface of the silicon wafer, incomplete corrosion, and only about 50% of the single silicon wafer effective die, which will cause a large amount of waste of raw materials and greatly increase the production cost. The effective die can be understood as the outermost part of the die on the whole surface of the silicon wafer, which is usually called the ineffective die, and the remaining part is the working die, which is called the effective die.

[0029] The prior art usually uses a rotating device to place the silicon wafer in the metal etching solution and rotates the silicon wafer to speed up the etching efficiency of the metal on the surface of the silicon wafer. However, this solution will cause the silicon wafer close to the center of rotation to move slowly and the silicon wafer far from the center of rotation to move quickly, resulting in uneven etching of the metal on the surface of the silicon wafer, and the silicon wafer may be damaged due to the fast movement and the inability to fix the silicon wafer firmly. In addition, the silicon wafer needs to be kept in the metal etching solution all the time to increase the contact time between the metal etching solution and the surface of the silicon wafer.

[0030] ​The application repeatedly controls the immersion and lifting of the silicon wafer by steps S1 and S2, wherein the immersion means that the silicon wafer is completely immersed in the metal etching solution, and the lifting means that the silicon wafer is completely lifted from the metal etching solution. When the silicon wafer is immersed in the metal etching solution, the TiNiAg on the surface of the silicon wafer reacts with the metal etching solution HNO3 to generate nitrate and nitrogen oxide gas. The nitrogen oxide is discharged from the metal etching solution or is dissolved in the metal etching solution, and the nitrate is attached to the outer surface of the silicon wafer to prevent further reaction of the TiNiAg with the metal etching solution. When the silicon wafer is lifted from the metal etching solution, the residual nitric acid on the surface of the silicon wafer flows downward along the surface of the silicon wafer, thereby taking away the nitrate attached to the outer surface of the silicon wafer, especially the nickel nitrate in the nitrate, which is an inorganic compound and has the physical property of weathering in the air. Therefore, it is easier to remove the nitrate on the surface of the silicon wafer after the silicon wafer is lifted from the metal etching solution. Experimental results prove that the effective die can be increased to more than 85%, greatly improving the utilization rate of the silicon wafer.

[0031] Compared with the prior art of rotating the silicon wafer, the application does not need to rotate the silicon wafer by repeatedly immersing and lifting the silicon wafer in the metal etching solution, so that the speed of each silicon wafer is the same, and the silicon wafer close to the rotation center does not have a small speed and the silicon wafer far from the rotation center does not have a large speed. The uniformity of the etching of the silicon wafer is ensured, the silicon wafer is prevented from being damaged due to excessive speed, and the residual metal etching solution on the surface of the silicon wafer flows downward due to gravity and inertia, taking away the product, i.e., the nitrate, on the surface of the silicon wafer, avoiding the attachment of the nitrate to the surface of the silicon wafer, preventing the etching reaction, and improving the reaction efficiency.

[0032] The movement cycle of the silicon wafer is one cycle from the beginning of immersion to complete lifting, each cycle is 1-2 seconds, and the speed is 0.5 m / s, so that the silicon wafer has sufficient impact force and is more easily cleaned of the nitrate on the surface of the silicon wafer. The first preset time is 1-20 minutes, and the specific time is adjusted according to the metal reaction activity on the surface of the silicon wafer and the concentration and temperature of the metal etching solution.

[0033] And because in the etching process of the silicon wafer, the metal film layer on the surface of the silicon wafer is getting thinner and thinner, and the product generated by the reaction with the metal etching solution is also getting less and less, it is not necessary to react for the first preset time every time, and the first preset time can be further set to a decreasing value, that is, the step S3: repeating the steps of immersing the reacted silicon wafer in the metal etching solution and waiting for the reaction for the first preset time, and taking the reacted silicon wafer out of the metal etching solution, until the step of etching the metal film layer on the surface of the silicon wafer is completed, with the increase of the number of repetitions, the first preset time gradually decreases. For example: the first time the silicon wafer is immersed in the metal etching solution for 20 minutes, the second time the silicon wafer is immersed in the metal etching solution for 19 minutes, the third time the silicon wafer is immersed in the metal etching solution for 18 minutes, and so on. Avoiding the situation that in the later stage of the etching reaction, the etching reaction is too long, and too much reaction product is generated on the surface of the silicon wafer, which cannot be removed by taking the silicon wafer out of the metal etching solution.

[0034] And the motion direction of the silicon wafer is kept in the vertical direction, that is, in the step of immersing the silicon wafer with the metal film layer on the surface into the metal etching solution, the silicon wafer is immersed into the metal etching solution along the vertical direction; in the step of waiting for the reaction for a preset time and taking the reacted silicon wafer out of the metal etching solution, the silicon wafer is taken out of the metal etching solution along the vertical direction. By controlling the motion direction of the silicon wafer to be in the same vertical line as the direction of the gravity of the silicon wafer, and then repeatedly immersing and taking out the silicon wafer from the metal etching solution, the generated nitrate on the surface of the silicon wafer can be removed more thoroughly by using the inertia and gravity.

[0035] When the step S1: immersing the silicon wafer with the metal film layer on the surface into the metal etching solution, the metal etching solution starts to stir, so that the concentration of the metal etching solution in contact with the surface of the silicon wafer is more uniform, improving the etching uniformity of the metal film layer on the surface of the silicon wafer, and the flowing metal etching solution can also carry away part of the nitrate attached to the surface of the silicon wafer, promoting the further reaction.

[0036] Further, as shown in the step S2: waiting for the reaction for a first preset time and taking the reacted silicon wafer out of the metal etching solution, specifically comprising: Figure 2

[0037] S20: waiting for the reaction for a first preset time and taking the reacted silicon wafer out of the metal etching solution;

[0038] S21: placing the reacted silicon wafer for 0.2-0.5s.

[0039] ​By allowing the silicon wafer to stand still, the metal etching solution can remove more nitrates from the surface. However, to prevent the metal etching solution from completely leaving the silicon wafer surface, resulting in uneven etching with less nitrates at the top and more at the bottom, the following experiment was conducted: When the standing time was controlled at 0.1 seconds, some residues remained on the silicon wafer surface. However, when the standing time was controlled at 0.6 seconds, the residues had completely left the silicon wafer surface. Therefore, the experimental results indicate that the standing time should be controlled within 0.2-0.5 seconds to ensure that the residues on the silicon wafer surface are removed by the metal etching solution while preventing the metal etching solution from completely leaving the silicon wafer surface, thus ensuring the uniformity of the etching process.

[0040] As the metal film on the silicon wafer becomes thinner during the etching process, the amount of products generated by the reaction with the metal etching solution also decreases. Therefore, it is not necessary to keep the wafer in the metal etching solution for such a long time each time to remove the products. The time for the silicon wafer to stand after being removed from the metal etching solution is not a fixed value, but a gradually decreasing value. That is, the steps of repeatedly immersing the reacted silicon wafer in the metal etching solution and waiting for the reaction for a first preset time, then removing the reacted silicon wafer from the metal etching solution until the metal film on the surface of the silicon wafer is etched are included: repeatedly immersing the reacted silicon wafer in the metal etching solution and waiting for the reaction for a first preset time, then removing the reacted silicon wafer from the metal etching solution and standing for a second preset time; and as the wet etching reaction proceeds, the thickness of the metal film on the surface of the silicon wafer continuously decreases, so the second preset time gradually decreases as the number of repetitions increases.

[0041] Specifically, the second preset time is 0.2-0.5 seconds. For example, the first resting time for the silicon wafer is 0.5 seconds, the second resting time is 0.47 seconds, the third resting time is 0.44 seconds, and so on until etching is complete. This avoids the problem of uneven etching of the metal film on the surface of the silicon wafer due to the thinning of the metal film layer after the silicon wafer has reacted for a period of time, and the excessive time spent removing the silicon wafer from the metal etching solution at this point.

[0042] Among them, such as Figure 3 As shown, in step S2: waiting for the reaction to proceed for a first preset time and then removing the reacted silicon wafer from the metal etching solution, the following additional steps are also included:

[0043] S20: Wait for the first preset reaction time, then remove the reacted silicon wafer from the metal etching solution;

[0044] S21: Let the reacted silicon wafer stand for 0.2-0.5 seconds;

[0045] S22: Rotate the reacted silicon wafer.

[0046] The rotation of the silicon wafer can accelerate the flow of the metal etching solution on the surface of the silicon wafer, more easily take away the generated nitrate, and also prevent the container loaded with the silicon wafer from blocking the flow of the metal etching solution. The specific rotation angle is preferably 180°, i.e. the silicon wafer is completely inverted, and then the silicon wafer is immersed in the metal etching solution again, i.e. the silicon wafer is lifted out of the metal etching solution, and after the completion of the standing, the part of the silicon wafer that is first lifted out of the metal etching solution, i.e. the upper half of the silicon wafer in the vertical direction, is inverted by rotating 180° along the axis of the silicon wafer, and when the silicon wafer is immersed in the metal etching solution again, the upper half of the silicon wafer is first immersed in the metal etching solution, preventing the problem of uneven etching of the metal film layer on the surface of the silicon wafer from occurring.

[0047] In addition, the application also sprays the metal etching solution on the surface of the reacted silicon wafer during the standing of the reacted silicon wafer in step S21. The surface of the silicon wafer lifted out of the metal etching solution is supplemented with the metal etching solution, and the metal etching solution sprayed on the surface of the silicon wafer accelerates the flow of the metal etching solution originally remaining on the surface of the silicon wafer, promoting the flow of the generated nitrate on the surface of the silicon wafer together with the metal etching solution.

[0048] Figure 4 is a schematic diagram of a silicon wafer wet etching device according to an embodiment of the application, as Figure 4 shown, a silicon wafer wet etching device 10 is disclosed, which comprises a reaction device 100, a fixing device 200 and a driving device 300, wherein the reaction device is used to place the metal etching solution; the fixing device 200 is used to fix the silicon wafer; and the driving device 300 cooperates with the fixing device 200 and the reaction device 100, and is used to immerse and lift the silicon wafer in the fixing device 200 in and out of the metal etching solution in the reaction device 100.

[0049] Specifically, the fixing device 200 is connected with the driving device 300, the reaction device 100 is arranged vertically below the fixing device 200, the driving device 300 controls the vertical up-and-down movement of the fixing device 200, and controls the fixing device 200 to repeatedly enter and exit the reaction device 100, so as to realize the immersion and lifting of the silicon wafer in the fixing device 200 in and out of the metal etching solution in the reaction device 100. That is, when the silicon wafer wet etching device is started, the driving device 300 starts to work, puts the fixing device 200 into the reaction device 100, and then lifts the fixing device 200 out of the reaction device 100.

[0050] Specifically, the reaction device 100 includes a metal etching liquid reaction tank, of course, it can also be other can load container; the fixing device 200 includes flower basket frame, of course, it can also use other structures such as mechanical arm and can place and fix the structure of silicon wafer; the driving device 300 includes motor and track, of course, it can also use other structures such as mechanical arm and can control the structure of fixing device 200; the metal etching liquid reaction tank is placed with metal etching liquid, the flower basket frame is placed with silicon wafer, one end of the track is connected with the output shaft of the motor, the other end is connected with the flower basket frame, the motor controls the flower basket frame to immerse and lift off the metal etching liquid reaction tank through the track.

[0051] And the wet etching device 10 of the silicon wafer further includes a turnover device 400, in the step S22: the silicon wafer after reaction is rotated, the turnover device 400 controls the rotation of the flower basket frame. The turnover device 400 tilts the surface of the silicon wafer by a certain angle while turning over, so that the generated product can flow out more conveniently.

[0052] The wet etching device 10 of the silicon wafer further includes a spraying device 500, which is arranged outside the reaction device 100, in the step S21: the silicon wafer after reaction is placed for 0.2-0.5s, when the silicon wafer is lifted off the metal etching liquid, the spraying device 500 sprays the surface of the silicon wafer in the flower basket frame with metal etching liquid; the spraying device further includes an infrared laser sensor, when the infrared sensor senses that the silicon wafer is lifted off the metal etching liquid, the spraying device is started to spray the silicon wafer, when the infrared sensor does not sense that the silicon wafer is lifted off the metal etching liquid (i.e. the silicon wafer is immersed in the metal etching liquid), the spraying device is turned off. Preferably, the spraying device is arranged directly above the flower basket frame, the metal etching liquid reaction tank, the flower basket frame and the spraying device are arranged in the same vertical straight line direction, the spraying device sprays the silicon wafer with metal etching liquid from top to bottom, which improves the flow rate of the metal etching liquid on the surface of the silicon wafer and more easily removes the generated nitrate on the surface of the silicon wafer. The spraying device further includes a water pump, which pumps the metal etching liquid in the metal etching liquid reaction tank to the spraying device.

[0053] The wet etching device 10 of the silicon wafer further includes a rotor device 600, which is arranged in the metal etching liquid reaction tank, in the step S1: the silicon wafer with a metal film layer on the surface is immersed in the metal etching liquid, when the infrared sensor does not sense that the silicon wafer is lifted off the metal etching liquid (i.e. the silicon wafer is immersed in the metal etching liquid), the rotor device 600 starts to rotate to stir the metal etching liquid in the metal etching liquid reaction tank; when the infrared sensor senses that the silicon wafer is lifted off the metal etching liquid, the rotor device stops rotating.

[0054] It should be noted that the definition of each step involved in the present scheme does not limit the order of the steps without affecting the implementation of the specific scheme. The steps written in the front can be executed first, or executed later, or even executed simultaneously, as long as the scheme can be implemented, it should be considered to belong to the protection scope of the present application.

[0055] It should be noted that the inventive concept of the present application can form a very large number of embodiments, but the length of the application file is limited and cannot be listed one by one, therefore, on the premise of not conflicting, the above described various embodiments or technical features can be combined to form new embodiments, and the combination of each embodiment or technical feature will enhance the original technical effect

[0056] The above is a further detailed description of the present application in combination with specific optional embodiments, which cannot be considered as limiting the specific implementation of the present application. For ordinary skilled persons in the art to which the present application belongs, without departing from the concept of the present application, a number of simple deductions or substitutions can be made, which should be considered to belong to the protection scope of the present application.

Claims

1. A wet etching method for silicon wafers, characterized in that the steps include... include: A silicon wafer with a metal film formed on its surface is immersed in a metal etching solution; Wait for the first preset reaction time, then remove the reacted silicon wafer from the metal etching solution and let it stand for 0.2-0.5 seconds. Repeat the steps of immersing the reacted silicon wafer in the metal etching solution and waiting for the first preset reaction time, then removing the reacted silicon wafer from the metal etching solution and letting it stand for a second preset time, which is 0.2-0.5 seconds, until the metal film layer on the surface of the silicon wafer is etched. Among them, the second preset time gradually decreases as the number of repetitions increases; when the silicon wafer with a metal film layer formed on its surface is immersed in the metal etching solution, the metal etching solution begins to stir, and the flowing metal etching solution can carry away some of the by-products attached to the surface of the silicon wafer; the metal etching solution is sprayed on the surface of the silicon wafer after the reaction.

2. The wet etching method for silicon wafers according to claim 1, characterized in that, The step of letting the reacted silicon wafer stand for 0.2-0.5 seconds further includes: The silicon wafer is rotated after it has been left to stand.

3. The wet etching method for silicon wafers according to claim 1, characterized in that, In the step of immersing a silicon wafer with a metal film layer formed on its surface into a metal etching solution, the silicon wafer is immersed in the metal etching solution in a vertical direction. In the step of waiting for the reaction to proceed for a preset time and then removing the reacted silicon wafer from the metal etching solution, the silicon wafer is removed from the metal etching solution vertically. After the step of waiting for the first preset reaction time and then removing the reacted silicon wafer from the metal etching solution, the method further includes: The reacted silicon wafer is then rotated.

4. A wet etching apparatus for silicon wafers, used in the wet etching method for silicon wafers according to any one of claims 1-3, characterized in that, The wet etching apparatus for the silicon wafer includes: A reaction apparatus used to hold the metal etching solution; Fixing device for fixing silicon wafers; and A driving device, in conjunction with the fixing device and the reaction device, is used to immerse or lift the silicon wafer in the fixing device into the metal etching solution in the reaction device.

5. The wet etching apparatus for silicon wafers according to claim 4, characterized in that, The reaction device includes a metal etching solution reaction tank, the driving device includes a motor and a track, and the fixing device includes a basket frame. The metal etching solution reaction tank contains metal etching solution, and the basket frame contains silicon wafers. One end of the track is connected to the output shaft of the motor, and the other end is connected to the basket frame. The motor controls the basket frame to be immersed in or lifted out of the metal etching solution reaction tank through the track.

6. The wet etching apparatus for silicon wafers according to claim 4, characterized in that, The wet etching apparatus for silicon wafers also includes a flipping device, which is connected to the flower basket frame and controls the flipping of the flower basket frame.

7. The wet etching apparatus for silicon wafers according to claim 4, characterized in that, The wet etching apparatus for silicon wafers also includes a spraying device, which is located outside the reaction apparatus and connected to the reaction apparatus. After the silicon wafer is removed from the metal etching solution, the surface of the silicon wafer is sprayed with the metal etching solution.

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