Cleaning process for reducing surface damage of silicon wafer
By using a mixed solution of hydrogen peroxide and dewaxing agent, along with a combination of overflow cleaning and ultrasonic cleaning, the problem of silicon wafer surface damage in existing cleaning processes has been solved, achieving efficient cleaning without damaging the silicon wafer.
Patent Information
- Application Number
- CN202511587153.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-31
- Publication Date
- 2026-02-13
AI Technical Summary
Existing cleaning processes struggle to ensure effective cleaning while avoiding damage to the silicon wafer surface.
A mixed solution containing hydrogen peroxide and a dewaxing agent is used as the dewaxing solution. A combination of overflow cleaning and ultrasonic cleaning processes, along with appropriate cleaning temperature and chemical concentration, are used to control cleaning parameters to reduce silicon wafer damage.
It effectively removes contaminants from the surface of silicon wafers, reduces damage to the silicon wafer surface, and improves the surface quality and cleaning effect of silicon wafers.
Smart Images
Figure CN121531949A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the technical field of semiconductor processing, and particularly relates to a cleaning process for reducing damage to the surface of a silicon wafer. BACKGROUND
[0002] In the semiconductor manufacturing industry, the cleaning of silicon wafers is mainly to remove particles, organic contaminants and metal contaminants on the surface of the silicon wafer to obtain a smooth and flat surface, which is a key link to ensure product quality and yield. The cleaning process in the prior art includes pure water cleaning, acid and alkali treatment, ultrasonic cleaning, spray cleaning, etc., which utilizes various chemical reagents and organic solvents to chemically react with or dissolve the contaminants adsorbed on the surface of the silicon wafer, combined with physical measures such as ultrasonic, heating, vacuuming, etc., to achieve the best cleaning state. However, in this process, irreversible damage to the surface of the silicon wafer often occurs. Therefore, how to ensure the cleaning effect while reducing the damage to the surface of the silicon wafer is one of the important technical problems to be solved in the field. SUMMARY
[0003] To solve the above technical problems, the present application provides a cleaning process for reducing damage to the surface of a silicon wafer, which can achieve good cleaning effect without causing damage to the silicon wafer, and improves the surface quality of the silicon wafer.
[0004] The technical scheme adopted by the present application is as follows: a cleaning process for reducing damage to the surface of a silicon wafer, comprising the following steps: removing wax from the silicon wafer in a wax removal tank, and the wax removal solution in the wax removal tank is a mixed solution containing hydrogen peroxide and a wax removal agent.
[0005] Further, the volume ratio of the wax removal solution is wax removal agent: hydrogen peroxide: deionized water = 1: (2-5): 100.
[0006] Further, after the wax removal, the silicon wafer is controlled to perform first overflow cleaning in a first pure water tank.
[0007] Further, after the pure water overflow cleaning, the silicon wafer is subjected to ultrasonic cleaning with a first liquid in a liquid tank.
[0008] Further, after the ultrasonic cleaning with the first liquid, the silicon wafer is subjected to second overflow cleaning in a second pure water tank.
[0009] Further, in the wax removal tank, the cleaning temperature is 40℃, the circulation flow rate of the wax removal solution is 15±3 L / min, and the wax removal agent is supplemented by 30 ml every 3 h; the hydrogen peroxide is supplemented by 100 ml every 3 h.
[0010] Further, in the first pure water tank and the second pure water tank, the circulation flow rate of the pure water is 15±3 L / min.
[0011] Further, in the liquid tank, the concentration ratio of the first liquid is ammonia water: hydrogen peroxide = 1: (5-10), the circulating flow is 20±3L / min; the ammonia water is supplemented by 100ml every 30min, the hydrogen peroxide is supplemented by 150ml every 30min; the ultrasonic power is 900±6W.
[0012] Further, the cleaning time of the silicon wafer in the wax removing tank, the liquid tank, the first pure water tank and the second pure water tank is 4.5min.
[0013] Further, before the silicon wafer is removed from the wax, the silicon wafer is placed in the LD tank for not more than 2H.
[0014] The cleaning process for reducing the surface damage of the silicon wafer has the advantages and positive effects that: the cleaning process for reducing the surface damage of the silicon wafer is used to clean the silicon wafer with a diameter of 200mm and a thickness of 500-1000um, which not only can reduce the surface granularity of the silicon wafer, ensure the cleaning effect of the silicon wafer, but also avoid the corrosion of the silicon wafer caused by the cleaning process, effectively reduce the surface damage of the silicon wafer, and improve the surface quality of the silicon wafer. BRIEF DESCRIPTION OF DRAWINGS
[0015] Figure 1 is a flow chart of the cleaning process for reducing the surface damage of the silicon wafer of the present application;
[0016] Figure 2 is a distribution diagram of all tank bodies in the cleaning process in a specific embodiment of the present application;
[0017] Figure 3 is a box plot of the silicon wafer granularity obtained by using the cleaning process of the present application and the existing cleaning process;
[0018] Figure 4 is a histogram of the silicon wafer surface particle distribution obtained by using the cleaning process of the present application and the existing cleaning process;
[0019] Figure 5 is a silicon wafer surface defect morphology diagram obtained by using the cleaning process of the present application.
[0020] Figure 6 is a silicon wafer surface defect morphology diagram obtained by using the existing cleaning process. DETAILED DESCRIPTION
[0021] The embodiments of the present application will be described below with reference to the accompanying drawings.
[0022] The present embodiment proposes a cleaning process for reducing the surface damage of the silicon wafer, and the process flow is as shown in Figure 1 The distribution of each tank body corresponding to the process is as shown in Figure 2 The cleaning process includes the following steps:
[0023] S1, taking out the polished silicon wafer and placing it in an LD tank;
[0024] Specifically, the silicon wafer in the embodiment is a wafer with a diameter of 200 mm and a processing thickness of 500 um-1000 um made by a polishing process. The polishing of the silicon wafer is achieved by the reaction of chemical components in the polishing liquid with the surface of the silicon wafer to generate soluble products, and then the mechanical friction of the polishing cloth removes the reaction products to realize surface planarization. However, some contaminants will inevitably remain on the surface of the polished silicon wafer, including wax, colloidal and other chemical contaminants (for example, added in the polishing liquid or formed during the polishing process), and some metals, debris or dust in the environment, etc. If these residual contaminants are not completely removed, they will significantly affect the electrical properties, surface flatness and subsequent process effect of the silicon wafer, so a cleaning process is needed after polishing is completed.
[0025] The cleaning process in the embodiment is carried out in a cleaning machine. Before cleaning, the polished silicon wafer can be placed in the LD tank of the cleaning machine. The LD tank is a pure water tank carrying a pure water solution. The polished silicon wafer is completely immersed in the pure water solution for no more than 2 hours.
[0026] S2, removing wax from the silicon wafer;
[0027] The cleaning machine is provided with a wax removal tank carrying a wax removal solution. The wax removal solution mainly removes chemical contaminants such as wax and colloidal on the surface of the silicon wafer through chemical reaction. In the present application, the wax removal solution is a mixed solution containing hydrogen peroxide and wax removal agent. The volume ratio of the wax removal solution is wax removal agent: hydrogen peroxide: deionized water = 1: (2-5): 100.
[0028] The wax removal agent is usually an organic solvent. For example, the wax removal agent is diethanolamine, tetramethylammonium hydroxide, toluene, acetone or anhydrous ethanol, etc. The wax removal solution in the prior art is made of a mixed solution of the wax removal agent and deionized water. The amount of the wax removal agent directly determines the cleaning effect of the silicon wafer. However, if the content of the wax removal agent is too high, it will have strong corrosiveness and cause damage to the surface of the silicon wafer. If the content of the wax removal agent is too low, it will not be able to completely remove the chemical contaminants on the surface of the silicon wafer, affecting the cleaning effect and ultimately leading to the fact that the wax removal solution in the prior art cannot achieve the effect of removing various chemical contaminants without damaging the silicon wafer. In the present application, the mixed solution containing hydrogen peroxide and wax removal agent is used as the wax removal solution. The hydrogen peroxide can form an oxidation layer on the surface of the silicon wafer, which helps to reduce the corrosion of the wax removal agent on the surface of the silicon wafer. By controlling the volume ratio of the wax removal solution to be wax removal agent: hydrogen peroxide: deionized water = 1: (2-5): 100, various chemical contaminants can be effectively removed to achieve good cleaning effect without causing damage to the silicon wafer, thereby improving the surface quality of the silicon wafer.
[0029] In the wax removal tank, the cleaning temperature is set to 40℃, the wax removal solution is in a circulating mode, the circulating flow rate of the wax removal solution is 15±3L / min, and the wax removal agent is supplemented by 30ml every 3h; the hydrogen peroxide is supplemented by 100ml every 3h, and the cleaning time is 4.5min.
[0030] In a preferred embodiment, the volume ratio of the wax removal solution is wax removal agent: hydrogen peroxide: deionized water = 1:3:100, which has good cleaning effect on a silicon wafer with a diameter of 200mm and a processing thickness of 500um-1000um.
[0031] S3, performing first overflow cleaning on the silicon wafer;
[0032] The silicon wafer after wax removal is transported to the first pure water tank, which is an overflow tank provided with an overflow pipeline and containing pure water, for removing the residual wax removal solution on the surface of the tank. During cleaning, the circulating flow rate of the pure water is 15±3L / min, the standby flow rate is 5L / min, and the cleaning time is 4.5min.
[0033] In the present application, the first pure water tank is used to keep the pure water in the tank in an overflow state, and the silicon wafer is cleaned by overflow. During overflow cleaning, the pure water can continuously flow over the surface of the silicon wafer, forming a uniform liquid layer covering, ensuring that the entire silicon wafer is immersed in the cleaning liquid. By providing an overflow pipeline, the pure water is continuously injected from the top and discharged from the bottom, forming a continuous liquid flow, which can quickly carry away the wax removal solution dissolved in the pure water, avoiding secondary pollution. Compared with the spray washing in the prior art, the wax removal solution residue on the silicon wafer can be removed more effectively. The above-mentioned first pure water tank can adopt any overflow tank structure in the prior art, which is not described or limited in detail here.
[0034] S4, performing first liquid ultrasonic cleaning on the silicon wafer;
[0035] After the first overflow cleaning of the silicon wafer, the silicon wafer is transported to the liquid tank for first liquid cleaning. In the present embodiment, the first liquid is SC1 liquid, which is used to remove particles and organic matter on the surface of the silicon wafer. The concentration ratio of the first liquid is ammonia water: hydrogen peroxide = 1: (5-10).
[0036] The first liquid is in a circulating form, and the circulating flow rate is 20±3L / min; among them, the ammonia water is supplemented by 100ml every 30min, and the hydrogen peroxide is supplemented by 150ml every 30min, so as to ensure the purity of the first liquid and the sustainability of the cleaning;
[0037] The liquid tank is provided with an ultrasonic device with an ultrasonic power of 900±6W to further improve the cleaning effect; the temperature in the liquid tank is 70℃.
[0038] The cleaning time of the No. 1 liquid ultrasonic cleaning is 4.5 minutes; in this embodiment, after a group of silicon wafers is cleaned by the No. 1 liquid ultrasonic cleaning, the next group of silicon wafers enters the wax removing tank to remove the wax, so as to realize continuous operation.
[0039] S5, performing second overflow cleaning on the silicon wafer;
[0040] The cleaning machine in this embodiment further comprises a second pure water tank, when the silicon wafer is cleaned by the No. 1 liquid, it is transferred to the second pure water tank to perform second overflow cleaning, so as to remove the No. 1 liquid, metal or particulate matter remaining on the surface of the silicon wafer.
[0041] The second pure water tank is also an overflow tank, and its specific structure can be the same as or different from that of the first pure water tank, as long as it can perform overflow cleaning; the second pure water tank also carries pure water, the circulating flow rate of the pure water is 15±3 L / min, the standby flow rate is 5 L / min, and the cleaning time is 4.5 minutes.
[0042] S6, performing slow pulling and drying on the silicon wafer.
[0043] After the second overflow cleaning, the silicon wafer enters the slow pulling tank and is subjected to slow pulling treatment in the slow pulling tank, and finally is subjected to infrared drying treatment in the drying chamber.
[0044] During the slow pulling cleaning process, the solution in the slow pulling tank is pure water, and the temperature of the pure water is 23℃; during the slow pulling treatment, the working flow rate of the pure water is also 15±3 L / min, and the standby flow rate is 5 L / min. Then, the silicon wafer after the slow pulling treatment is dried in the drying chamber to obtain a dry and clean silicon wafer.
[0045] The above cleaning processes are all performed in the cleaning machine, so that the silicon wafer cleaning is performed in a clean and closed environment; before the wax removing, the fan filter unit and the exhaust system of the cleaning machine are set to be coordinated with each other, so that the inside of the cleaning machine is in a positive pressure state, and the cleanliness of the inside environment of the Baocheng cleaning machine is ensured.
[0046] In order for those skilled in the art to further understand the method of the present application, the technical solutions of the present application will be explained in detail below in combination with specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments.
[0047] Embodiment 1
[0048] A cleaning process for reducing the surface damage of a silicon wafer, which is used for cleaning the polished silicon wafer, the diameter of the silicon wafer is 200 mm, and the thickness is 800 um, comprising the following steps:
[0049] S1, taking out the polished silicon wafer and placing it in the LD tank;
[0050] After polishing, the silicon wafer is transferred from the polishing machine to the LD tank and completely immersed in the pure water solution for 2h.
[0051] S2, the silicon wafer is dewaxed;
[0052] Diethanolamine is used as the dewaxing agent, and the dewaxing solution is prepared according to the volume ratio of dewaxing agent: hydrogen peroxide: deionized water = 1:3:100;
[0053] The silicon wafer is placed in the dewaxing tank for dewaxing; the cleaning temperature in the dewaxing tank is set to 40℃, the dewaxing solution is circulated, the circulation flow rate of the dewaxing solution is 15L / min, and the dewaxing agent is supplemented by 30ml every 3h; the hydrogen peroxide is supplemented by 100ml every 3h, and the cleaning time is 4.5min.
[0054] S3, the silicon wafer is subjected to first overflow cleaning;
[0055] The dewaxed silicon wafer is transferred to the first pure water tank for pure water overflow cleaning, the first pure water tank is an overflow tank, the first pure water tank contains pure water, the circulation flow rate of the pure water is 15L / min, the standby flow rate is 5L / min, the cleaning time is 4.5min, and the temperature is normal temperature.
[0056] S4, the silicon wafer is subjected to No. 1 liquid ultrasonic cleaning;
[0057] After the first overflow cleaning, the silicon wafer is transferred to the liquid tank for No. 1 liquid cleaning. In this embodiment, the No. 1 liquid is SC1 liquid, and the concentration ratio of the No. 1 liquid is ammonia water: hydrogen peroxide: deionized water = 0.8:3:100.
[0058] The No. 1 liquid is circulated at a circulation flow rate of 20L / min; among them, the ammonia water is supplemented by 100ml every 30min, and the hydrogen peroxide is supplemented by 150ml every 30min; the liquid tank is provided with an ultrasonic device, the ultrasonic power is set to 900W, the temperature in the liquid tank is 70℃, and the cleaning time is 4.5min.
[0059] S5, the silicon wafer is subjected to second overflow cleaning;
[0060] After the No. 1 liquid cleaning, the silicon wafer is subjected to second overflow cleaning in the second pure water tank, the second pure water tank is an overflow tank, the second pure water tank contains pure water, the circulation flow rate of the pure water is 15L / min, the standby flow rate is 5L / min, the cleaning time is 4.5min, and the temperature is normal temperature.
[0061] S6, the silicon wafer is subjected to slow pulling and drying.
[0062] The silicon wafer after the second overflow cleaning enters the slow pulling slot and is subjected to slow pulling treatment in the slow pulling slot. The solution in the slow pulling slot is pure water, and the temperature of the pure water is 23℃. During the slow pulling treatment, the working flow rate of the pure water is also 15L / min, and the standby flow rate of the pure water is 5L / min. Then, the silicon wafer after the slow pulling treatment is subjected to drying in the drying chamber to obtain a dry and clean silicon wafer.
[0063] The particle size of the silicon wafer after cleaning is tested by using a KLASPX device. Each silicon wafer is tested for 3 times, and the test data is averaged to obtain the data of the particle size of 40nm and 60nm particles as shown in the box plot of Figure 3 The average value of the LPD-0.04 particle density of the silicon wafer obtained by using the cleaning process of the present application is 15.35, and the average value of the LPD-0.06 particle of the silicon wafer obtained is 1.26. The lower the particle size, the better the quality of the surface of the silicon wafer. The number distribution of the particle size of 40nm is analyzed to form a histogram as shown in Figure 4 The higher the density corresponding to the smaller number of particles, the better the quality of the surface of the silicon wafer.
[0064] The morphology of the surface of the silicon wafer after cleaning is detected by using an optical detector to obtain the defect morphology diagram of the surface of the silicon wafer as shown in Figure 5 It can be seen that the surface of the silicon wafer has no corrosion morphology, and the remaining defects are mechanical damage formed by the polishing pad bristles and the surface of the silicon wafer in the polishing process. Such abnormalities cannot be removed by cleaning.
[0065] Comparative Example 1
[0066] A cleaning process in the prior art is used to clean the polished silicon wafer. The diameter of the silicon wafer is 200mm, and the thickness is 800um. The process includes the following steps:
[0067] S1. The polished silicon wafer is taken out and placed in an LD slot.
[0068] After polishing, the silicon wafer is transferred from the polishing machine to the LD slot and completely immersed in the pure water solution for standby. The standby time is 6h.
[0069] S2. The silicon wafer is dewaxed.
[0070] Diethanolamine is used as a dewaxing agent, and a dewaxing solution is prepared according to the volume ratio of the dewaxing agent to deionized water of 1:100. The cleaning temperature in the dewaxing slot is set to 40℃. The dewaxing solution is used in a circulating manner, and the circulating flow rate of the dewaxing solution is 15L / min. The dewaxing agent is supplemented by 30ml every 3h, and the cleaning time is 4.5min.
[0071] S3. The silicon wafer is subjected to first spray cleaning.
[0072] The silicon wafer after wax removal is transferred to the first spray tank for spray cleaning, the flow rate is 22 L / min, the cleaning time is 4.5 min, and the temperature is normal temperature.
[0073] S4, the silicon wafer is ultrasonically cleaned with No. 1 liquid and No. 2 liquid;
[0074] After the first spray cleaning of the silicon wafer, the silicon wafer is transferred to the liquid tank for No. 1 liquid cleaning. In this embodiment, the No. 1 liquid is SC1 liquid, and the concentration ratio of the No. 1 liquid is ammonia water: hydrogen peroxide: deionized water = 0.8:3:100.
[0075] The No. 1 liquid is in a circulating form, and the circulating flow rate is 20 L / min; wherein, the ammonia water is supplemented by 100 ml every 30 min, and the hydrogen peroxide is supplemented by 150 ml every 30 min; the liquid tank is provided with an ultrasonic device, the ultrasonic power is set to 900 W, the temperature in the liquid tank is 70℃, and the cleaning time is 4.5 min;
[0076] Then, the silicon wafer after ultrasonic cleaning with the No. 1 liquid is transferred to another liquid tank for No. 2 liquid cleaning, and the No. 2 liquid is SC2 liquid, and the concentration ratio of the No. 2 liquid is ammonia water: hydrogen peroxide: deionized water = 0.5:3:100.
[0077] The No. 2 liquid is in a circulating form, and the circulating flow rate is 20 L / min; wherein, the ammonia water is supplemented by 100 ml every 30 min, and the hydrogen peroxide is supplemented by 150 ml every 30 min; the liquid tank of the No. 2 liquid is also provided with an ultrasonic device, the ultrasonic power is set to 900 W, the temperature in the liquid tank is 70℃, and the cleaning time is 4.5 min.
[0078] S5, the silicon wafer is secondarily spray cleaned;
[0079] After the No. 2 liquid cleaning of the silicon wafer, the silicon wafer enters the second spray tank for secondary spray cleaning, the flow rate is 22 L / min, the cleaning time is 4.5 min, and the temperature is normal temperature.
[0080] S6, the silicon wafer is slowly pulled up and dried.
[0081] The silicon wafer after the secondary spray cleaning enters the slow pulling-up tank and is subjected to slow pulling-up treatment in the slow pulling-up tank, the solution in the slow pulling-up tank is pure water, the temperature is 23℃, and during the slow pulling-up treatment, the working flow rate of the pure water is also 15 L / min, and the standby flow rate is 5 L / min. Then, the silicon wafer after the slow pulling-up treatment is dried in the drying chamber to obtain a dry and clean silicon wafer.
[0082] The particle size on the surface of the silicon wafer after cleaning is tested by using a KLASPX device, 3 times for each silicon wafer, and the test data is averaged to obtain the detection data of 40nm and 60nm particle size as shown in the box plot of Figure 3 The average of the LPD-0.04 particle density of the silicon wafer obtained by using the cleaning process of the prior art is 20.98, and the average of the LPD-0.06 particle of the silicon wafer obtained is 2.18; the lower the particle size, the better the quality of the surface of the silicon wafer; wherein, the number distribution of the 40nm particle size is analyzed to form a histogram as shown in Figure 4 The higher the density corresponding to the smaller number of particles, the better the quality of the surface of the silicon wafer.
[0083] The morphology of the surface of the silicon wafer after cleaning is detected by using an optical detector to obtain the surface defect morphology of the silicon wafer as shown in Figure 6 It can be seen that the surface of the silicon wafer presents obvious corrosion morphology, which is caused by chemical corrosion of the surface of the silicon wafer during the cleaning process.
[0084] As can be seen from the example results in Figure 3 , Figure 4 The cleaning process of the present application can obtain lower particle size, effectively improving the cleaning effect of the silicon wafer; as can be seen from the example results in Figure 5 , Figure 6 The cleaning process of the present application can effectively avoid the corrosion of the surface of the silicon wafer, improve the surface quality of the silicon wafer, and improve the competitiveness of the silicon wafer in the market. Moreover, the cleaning process of the present application can also improve the yield of the product and reduce the scrap cost.
[0085] The cleaning process for reducing the damage of the surface of the silicon wafer proposed in the present application can be used to clean the silicon wafer with a diameter of 200mm and a thickness of 500-1000um, which not only can reduce the particle size on the surface of the silicon wafer, ensure the cleaning effect of the silicon wafer, but also can avoid the corrosion of the silicon wafer caused by the cleaning process, effectively reduce the damage of the surface of the silicon wafer, and improve the surface quality of the silicon wafer.
[0086] The above detailed description of the embodiments of the present application, but the content described is only the preferred embodiment of the present application, and cannot be considered as limiting the scope of the present application. Any equivalent changes and improvements made within the scope of the present application shall still belong to the patent scope of the present application.
Claims
1. A cleaning process for reducing damage to silicon wafer surfaces, characterized in that, Includes the following steps: The silicon wafer is dewaxed in a dewaxing tank, wherein the dewaxing solution in the dewaxing tank is a mixed solution containing hydrogen peroxide and a dewaxing agent.
2. The cleaning process for reducing surface damage to silicon wafers according to claim 1, characterized in that: The volume ratio of the dewaxing solution is dewaxing agent: hydrogen peroxide: deionized water = 1: (2-5):
100.
3. The cleaning process for reducing silicon wafer surface damage according to claim 2, characterized in that: After dewaxing, the silicon wafers are subjected to a first overflow cleaning in the first pure water tank.
4. The cleaning process for reducing surface damage to silicon wafers according to claim 3, characterized in that: After the pure water overflow cleaning, the solution enters the chemical tank for ultrasonic cleaning with the No. 1 solution.
5. The cleaning process for reducing surface damage to silicon wafers according to claim 4, characterized in that: After ultrasonic cleaning with the first liquid, it enters the second pure water tank for a second overflow cleaning.
6. The cleaning process for reducing surface damage to silicon wafers according to claim 2, characterized in that: In the dewaxing tank, the cleaning temperature is 40℃, the circulation flow rate of the dewaxing solution is 15±3L / min, and the dewaxing agent is replenished by 30ml every 3 hours; the hydrogen peroxide is replenished by 100ml every 3 hours.
7. The cleaning process for reducing surface damage to silicon wafers according to claim 5, characterized in that: In the first pure water tank and the second pure water tank, the circulation flow rate of pure water is 15±3L / min.
8. The cleaning process for reducing surface damage to silicon wafers according to claim 4, characterized in that: In the drug solution tank, the concentration ratio of the first solution is ammonia:hydrogen peroxide = 1:(5-10), and the circulation flow rate is 20±3L / min; 100ml of ammonia is added every 30min, and 150ml of hydrogen peroxide is added every 30min; the ultrasonic power is 900±6W.
9. The cleaning process for reducing silicon wafer surface damage according to claim 5, characterized in that: The cleaning time for the silicon wafer in the dewaxing tank, the chemical solution tank, the first pure water tank, and the second pure water tank is 4.5 minutes.
10. The cleaning process for reducing surface damage to silicon wafers according to claim 1, characterized in that: Before dewaxing the silicon wafer, the silicon wafer is placed in an LD bath for no more than 2 hours.