Improved rca cleaning process and cleaning apparatus

Abstract

The application relates to the technical field of RCA cleaning, and discloses an improved RCA cleaning process and cleaning equipment, which provides an RCA cleaning process for a silicon wafer, wherein a mixed acid solution is configured, two original pickling steps are reduced, one-step pickling can achieve the original cleaning effect, the whole cleaning process is mostly under room temperature, the use of chemical agents is reduced while the pickling steps are reduced, the cost is reduced, and the cleaning quality can be ensured. Through a liquid receiving plate, the liquid receiving plate is always horizontally located at the bottom of the cleaning container during the transfer process of the cleaning container, is used for receiving the falling waste liquid, avoids waste liquid pollution of a table or a cleaning tank, the liquid receiving plate can also be controlled by a mechanical arm, the position is adjusted to avoid interference with the action of the workbench, and the liquid receiving plate can also be automatically cleaned in the cleaning tank after receiving the waste liquid.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of RCA cleaning, in particular, to an improved RCA cleaning process and cleaning equipment. BACKGROUND

[0002] RCA is a typical and most commonly used wet chemical cleaning method, which mainly includes the following cleaning solutions.

[0003] (1) SPM: H2SO4 / H2O 2120~150℃ SPM has high oxidation capacity, which can oxidize the metal and dissolve in the cleaning solution, and can oxidize the organic matter to CO2 and H2O. Cleaning the silicon wafer with SPM can remove heavy organic contamination and part of the metal on the surface of the silicon wafer, but when the organic contamination is particularly serious, the organic matter will be carbonized and difficult to remove.

[0004] (2) HF (DHF): HF (DHF) 20~25℃ DHF can remove the natural oxide film on the surface of the silicon wafer, so that the metal attached to the natural oxide film will be dissolved into the cleaning solution, and DHF can inhibit the formation of the oxide film. Therefore, Al, Fe, Zn, Ni and other metals on the surface of the silicon wafer can be easily removed, and DHF can also remove the metal hydroxide attached to the natural oxide film. When the natural oxide film is corroded, the silicon on the surface of the silicon wafer is almost not corroded.

[0005] (3) APM (SC-1): NH4OH / H2O2 / H2O 30~80℃ Due to the action of H2O2, there is a natural oxide film (SiO2) on the surface of the silicon wafer, which is hydrophilic, and the surface of the silicon wafer and the particles can be immersed in the cleaning solution. Because the natural oxide layer on the surface of the silicon wafer is corroded by NH4OH, the particles attached to the surface of the silicon wafer fall into the cleaning solution, thereby achieving the purpose of removing the particles. While NH4OH corrodes the surface of the silicon wafer, H2O2 forms a new oxide film on the surface of the silicon wafer.

[0006] (4) HPM (SC-2): HCl / H2O2 / / H2O 65~85℃ Used to remove sodium, iron, magnesium and other metal contamination on the surface of the silicon wafer. HPM can remove Fe and Zn at room temperature.

[0007] The general idea of cleaning is to first remove the organic contamination on the surface of the silicon wafer, because the organic matter will cover part of the surface of the silicon wafer, so that the oxide film and the related contamination will be difficult to remove; then dissolve the oxide film, because the oxide layer is a "contamination trap" and will also introduce epitaxial defects; finally, remove the particle, metal and other contamination, and passivate the surface of the silicon wafer.

[0008] At present, with the development of new cleaning process, the purpose is mainly to reduce the process steps and the use of ultra-clean water and chemical solution under room temperature conditions, so as to achieve good cleaning effect, reduce cost, improve cleaning quality, facilitate waste liquid recovery and utilization, and reduce environmental pollution. SUMMARY

[0009] The application provides an improved RCA cleaning process and cleaning equipment, which simplifies two conventional pickling steps into one by using mixed acid solution, so as to reduce cost and improve cleaning efficiency.

[0010] To this end, the technical scheme adopted is as follows:

[0011] An improved RCA cleaning process comprises the following steps:

[0012] S1: placing a silicon wafer into a cleaning container, and immersing the cleaning container in deionized water;

[0013] S2: taking out the cleaning container and transferring it into a mixed acid solution, and soaking for 40s-60s under the condition of-10℃~-5℃;

[0014] S3: taking out the cleaning container from the mixed acid solution, and rinsing the silicon wafer with deionized water until all chemical substances are rinsed clean;

[0015] S4: transferring the cleaning container into an ultrasonic cleaner, and cleaning for 200s-300s under the cleaning frequency of 28KHZ-40KHZ;

[0016] S5: taking out the cleaning container and the silicon wafer, and placing the silicon wafer into a dryer for drying treatment until no water residue is left on the surface of the silicon wafer.

[0017] Further technical scheme is that the mixed acid solution comprises HNO3 with a concentration of 65%-68%, HF with a concentration of 40%-50%, CH3COOH with a concentration of 95%-98% and H2SO4 with a concentration of 95%-98%, and the volume ratio of the four is 3:1:1:3.

[0018] An improved RCA cleaning device, comprising a device main body, the device main body comprising a control system, a liquid preparation and supply system, a liquid discharge system and a working cabin, a plurality of cleaning grooves are formed on the workbench of the working cabin, and the device is suitable for any one of the improved RCA cleaning processes; further comprising a cleaning container matched with the cleaning grooves for containing silicon wafers, a lifting mechanism capable of transferring the cleaning container to different cleaning grooves is fixed on the top of the working cabin, the cleaning grooves are four, which are immersion grooves, pickling grooves, flushing grooves and ultrasonic grooves, a mechanical arm is fixed on the side wall of the working cabin, a liquid receiving plate is fixed on the working end of the mechanical arm, and the liquid receiving plate is always horizontally located at the bottom during the transfer of the cleaning container.

[0019] Further technical solutions are that the liquid receiving plate is in a horizontal state and is in a downwardly recessed arc structure.

[0020] Further technical solutions are that a clamping hole is formed on the outer edge of the liquid receiving plate, the working end of the mechanical arm is a clamping structure, the clamping structure comprises two clamping blocks with adjustable spacing, clamping blocks are fixed on the surfaces of the two clamping blocks that are close to each other, and the clamping blocks are matched with the clamping hole.

[0021] Further technical solutions are that the cleaning container is a square tube structure, a plurality of parallel strip-shaped positioning holes are formed on one side wall of the cleaning container, a plurality of strip-shaped insertion holes corresponding to the strip-shaped positioning holes are formed on the other three side walls, and the three strip-shaped insertion holes corresponding to the same strip-shaped positioning hole are integrated.

[0022] Further technical solutions are that a lifting hook is fixed at the lifting position of the lifting mechanism, and a hooking groove matched with the lifting hook is formed on the edge of the cleaning container.

[0023] Further technical solutions are that the lifting hook is a double-hook structure with adjustable distance, and the two hooks hook the two sides of the cleaning container.

[0024] The working principle and beneficial effects of the present application are as follows:

[0025] 1. A process method is provided for RCA cleaning of silicon wafers, by configuring a mixed acid solution, the original two pickling steps are reduced, only one pickling step can achieve the original cleaning effect, the whole cleaning process is mostly under room temperature conditions, the use of chemical agents is reduced while the pickling steps are reduced, the cost is reduced, and the cleaning quality can be guaranteed.

[0026] 2. The liquid receiving plate is always horizontally located at the bottom of the cleaning container during the transferring process of the cleaning container, and is used for receiving the waste liquid, so as to avoid the pollution of the platform or the cleaning tank by the waste liquid. Meanwhile, the liquid receiving plate can be controlled by the mechanical arm, and is adjusted to be received on the side wall of the working cabin, so as to avoid the interference with other operations on the platform. In addition, the liquid receiving plate can be automatically cleaned in the deionized water in the cleaning tank after receiving the waste liquid.

[0027] 3. The cleaning container is used for containing the silicon wafer, and the strip-shaped positioning holes have a certain gap, so that the water flow can enter and flush without being hindered. The silicon wafer is inserted from the strip-shaped insertion hole and positioned by the strip-shaped positioning hole, and the size of the silicon wafer is not limited. During the cleaning, the cleaning container can be adjusted and placed according to the actual situation, so that the silicon wafer is placed vertically or horizontally. BRIEF DESCRIPTION OF DRAWINGS

[0028] The application will be further described in detail below in combination with the drawings and specific embodiments.

[0029] Figure 1 It is a schematic diagram of the overall structure of the device body of the application;

[0030] Figure 2 It is a schematic diagram of the cross-sectional structure of the device body of the application;

[0031] Figure 3 It is a schematic diagram of the top view structure of the cleaning tank of the application;

[0032] Figure 4 It is a schematic diagram of the structure of the cleaning container of the application;

[0033] Figure 5 It is a schematic diagram of the structure of the mechanical arm of the application;

[0034] Figure 6 It is a schematic diagram of the structure of the liquid receiving plate of the application.

[0035] In the figure: 1, cleaning container; 11, strip-shaped positioning hole; 12, strip-shaped insertion hole; 13, hooking groove; 2, lifting mechanism; 21, lifting hook; 31, immersion tank; 32, pickling tank; 33, flushing tank; 34, ultrasonic tank; 4, mechanical arm; 41, liquid receiving plate; 411, clamping hole; 42, clamping block; 421, clamping block. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the application will be clearly and completely described below in combination with the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are involved in the protection scope of the application.

[0037] An improved RCA cleaning process, comprising the following steps:

[0038] Preparation: Prepare the required chemicals, including deionized water, HNO3, HF and CH3COOH, H2SO4, etc., and ensure that all the equipment and containers used are clean.

[0039] S1: Put the silicon wafer into the cleaning container 1, and immerse the cleaning container 1 in deionized water.

[0040] The purpose here is to remove the impurities on the surface of the silicon wafer. Deionized water has very high purity and contains almost no impurities and ions. When the silicon wafer is placed in it, some soluble impurities, dust, particulate matter and other contaminants on the surface of the silicon wafer can be removed through soaking and flushing, playing a role in preliminary cleaning and creating better conditions for subsequent formal cleaning steps. If there are contaminants on the surface of the silicon wafer, direct subsequent cleaning may cause the contaminants to spread or transfer to other parts during the cleaning process. By placing it in deionized water first, the contaminants can be dissolved or suspended in the water, reducing their residue and spread on the surface of the silicon wafer, thereby cleaning more effectively.

[0041] And the silicon wafer may generate static electricity during processing, transportation, etc., causing some charged particles to be adsorbed on the surface. Deionized water can play a certain conductive role, helping to neutralize or eliminate static electricity on the surface of the silicon wafer, reducing the impact of static electricity on the cleaning process and the quality of the silicon wafer. At the same time, soaking in deionized water can fully moisten the surface of the silicon wafer, which is conducive to better contact and action between the subsequent cleaning solution and the surface of the silicon wafer, improving the cleaning effect and efficiency. For example, in some cleaning processes, deionized water is used for soaking first, and then mixed acid is used for cleaning, which can more thoroughly remove various contaminants on the surface of the silicon wafer.

[0042] S2: Take out the cleaning container 1 and transfer it to a mixed acid solution, soak for 40s~60s at -10℃~-5℃; wherein the mixed acid solution contains HNO3 with a concentration of 65%~68%, HF with a concentration of 40%~50%, CH3COOH with a concentration of 95%~98%, and H2SO4 with a concentration of 95%~98%, and the volume ratio of the four is 3:1:1:3.

[0043] It should be noted that in the actual cleaning process, the concentrations of the mixed acid solution, the solution temperatures, and the frequency of the following ultrasonic cleaning can be flexibly adjusted according to different processes, and the embodiments of the present application do not make specific limitations.

[0044] The above-mentioned mixed acid solution is mainly used to remove SiO2, metal ions and organic molecules on the surface of the silicon wafer.

[0045] The CH3COOH can form a complex with the metal ions on the surface of the silicon wafer. The carboxyl group (-COOH) in CH3COOH can undergo coordination reaction with the metal ions to form a stable complex. The solubility of this complex in the cleaning solution is relatively high, so that the metal ions can be removed from the surface of the silicon wafer.

[0046] In addition, the pH value of the mixed acid solution needs to be accurately controlled. CH3COOH, as a weak acid, can act as a buffer in the entire mixed acid solution. When the pH value of the mixed acid solution fluctuates due to other chemical reactions, CH3COOH can release or absorb hydrogen ions (H + ), thereby maintaining the relative stability of the pH value of the cleaning solution.

[0047] At the same time, due to the hydrophobicity of the surface of the silicon wafer, CH3COOH can improve the wettability of the mixed acid solution on the surface of the silicon wafer. CH3COOH molecules can be adsorbed on the surface of the silicon wafer, reducing the surface energy of the silicon wafer, so that the mixed acid solution can spread better on the surface of the silicon wafer, thereby improving the cleaning efficiency and ensuring that all areas of the surface of the silicon wafer can be cleaned.

[0048] Especially important is that after the cleaning of the mixed acid solution is completed, the presence of CH3COOH can form a protective film on the surface of the silicon wafer. This protective film can prevent the silicon wafer from being contaminated again by pollutants in the surrounding environment, such as dust and volatile organic compounds in the air, after being taken out of the mixed acid solution. Moreover, during the subsequent drying and processing process, this protective film can gradually evaporate without causing adverse effects on the surface of the silicon wafer.

[0049] H2SO4 can react with some metals to form corresponding sulfates. In the removal of metal from the surface of the silicon wafer, it cooperates with other solutions in the mixed acid solution to provide certain chemical environment and reaction conditions for the entire process of removing metal, which is more conducive to removing metal impurities in the silicon wafer.

[0050] HF has a unique chemical etching ability for SiO2, which can dissolve and remove it, thereby effectively removing the oxide layer on the surface of the silicon wafer. This selective etching is very critical because it can accurately remove the oxide layer without significantly eroding the silicon substrate. Therefore, by controlling the concentration, temperature and cleaning time of HF and other parameters, the selective removal of silicon oxide can be achieved, which helps to maintain the flatness and structural integrity of the surface of the silicon wafer.

[0051] HNO3 has strong oxidizing property, and many metals can be oxidized to form soluble metal nitrates in nitric acid. Through this oxidation reaction, the metal impurities are dissolved from the surface of the silicon wafer into the mixed acid solution and thus removed. HNO3 can convert these metal impurities into ionic form, making them easier to be cleaned from the surface of the silicon wafer.

[0052] And HNO3 can react with organic matter, some organic matter will be decomposed into small molecules such as CO2, H2O, etc. under the strong oxidation of HNO3. For complex organic pollutants, the strong oxidizing property of HNO3 can destroy its molecular structure, making it become small molecular fragments that are more soluble in water or other cleaning liquids, and then be cleaned.

[0053] Therefore, by continuously adjusting the concentrations and proportions of various solutions, a mixed acid solution as described in the examples can be configured to thin the silicon wafer by 5-8 um, while removing SiO2, metal ions, and organic molecules attached to the surface layer of the channel, achieving the purpose of acid washing in RCA cleaning. The main chemical reactions that occur are as follows:

[0054] Si + 4HNO3 + 6HF = H2SiF6 + 4NO2 + 4HO2

[0055] The generated H2SiF6, NO2, and HO2 can continue to react and decompose in the mixed acid solution, producing H2, O2, or solid impurities, and ultimately being further treated in the waste liquid.

[0056] During the entire cleaning process, the temperature needs to be considered both in terms of the intensity of the internal reaction of the solution and the volatility characteristics of the acidic solution, so it is set to -10℃~-5℃, and the mixed acid solution is soaked for 40s~60s.

[0057] S3: Take the cleaning container 1 out of the mixed acid solution, and rinse the silicon wafer with deionized water until all chemicals are rinsed clean.

[0058] During the mixed acid solution cleaning process, the mixed acid solution reacts with the contaminants on the surface of the silicon wafer. Although the mixed acid solution can remove many impurities, after the reaction is complete, the mixed acid solution itself will remain on the surface of the silicon wafer. If these residual solutions are not removed in time, when the silicon wafer enters the subsequent process steps, the residual solutions may continue to react with the silicon wafer or other substances, affecting the performance of the silicon wafer. Moreover, during the reaction of the mixed acid solution with the impurities on the surface of the silicon wafer, some newly generated impurities or incompletely reacted impurities may be carried.

[0059] Therefore, by rinsing with deionized water, these impurities carried by the mixed acid solution can be effectively washed away from the surface of the silicon wafer, thereby ensuring the cleanliness requirements of the subsequent process on the surface of the silicon wafer.

[0060] S4: Transfer the cleaning container 1 to an ultrasonic cleaner, and clean it at a cleaning frequency of 28KHZ~40KHZ for 200s-300s.

[0061] The high-frequency vibrations generated by ultrasonic waves can cause the cleaning liquid to produce countless tiny bubbles. These bubbles generate strong impact forces during their formation, growth, and rupture. This impact force can effectively remove particulate contaminants on the surface of the silicon wafer, such as tiny dust particles and metal particles. Even some particles with strong adsorption forces are more likely to be carried away by the cleaning liquid under the action of ultrasonic waves. For organic contaminants on the surface of the silicon wafer, ultrasonic waves can promote chemical reactions between the cleaning liquid and the organic contaminants. It can make the cleaning liquid better penetrate the interface between the organic contaminants and the surface of the silicon wafer, speed up the decomposition and dissolution process of the organic contaminants, and thus improve the efficiency and quality of cleaning.

[0062] The cleaning frequency used in this step is low frequency 28KHZ~40KHZ. The bubbles generated by low-frequency ultrasonic waves are larger, and the energy released when they burst is higher, with stronger impact force. Therefore, it is better for removing larger particulate contaminants and some contaminants with strong adhesion on the surface of the silicon wafer. This step is located after the mixed acid solution, which can thoroughly remove impurities on the surface of the silicon wafer.

[0063] S5: Take out the cleaning container 1 and take out the silicon wafer and put it into a dryer for drying treatment until there is no water residue on the surface of the silicon wafer.

[0064] One embodiment of the dryer is to put the silicon wafer carrier into a cartridge holder inside a cylindrical container. In the center of this cylindrical container is a row of perforated tubes connected to deionized water and hot ammonia gas. The spin-drying process actually starts with the rinsing of the silicon wafer, as the silicon wafer is rotated around the central water-spraying pipe column. Then, when hot nitrogen gas is sprayed from the central pipe column, the spin-dryer switches to high-speed rotation, which spins the water off the surface of the silicon wafer while the hot nitrogen gas helps remove small water droplets tightly attached to the wafer.

[0065] After the entire improved RCA cleaning process is completed, the silicon wafer is detected by an oscilloscope. The test end of the oscilloscope probe is contacted to the position on the silicon wafer where leakage is to be measured. If the silicon wafer has specific electrodes or pins for testing leakage, the probe should be connected to the corresponding position. Start the data acquisition function of the oscilloscope, and measure the leakage of the silicon wafer, and observe the voltage waveform displayed on the screen of the oscilloscope. If there is leakage, a stable DC voltage or a slight fluctuation may be seen. The temperature of the silicon wafer during the entire process can be controlled by a high-low temperature box.

[0066] According to the voltage value displayed on the oscilloscope, the resistance and other related parameters of the silicon wafer are known, the size of the leakage current can be calculated, and then the result is analyzed. The detection data and results are shown in Table 1.

[0067] Table 1:

[0068]

[0069] As shown in the above table, in the original RCA standard cleaning process, two kinds of acid solutions need to be added during pickling. After converting the two kinds of acid solutions into the mixed acid solution described in the application examples, and combining with the ultrasonic wave and deionized water rinsing of the silicon wafer in the examples, the final test results meet the cleaning requirements, so that the mixed acid solution of the application can replace the existing two kinds of acid solutions. In this way, only one step of pickling can achieve the original cleaning effect, while reducing the pickling steps, reducing the use of chemical agents, reducing the cost, and ensuring the cleaning quality.

[0070] As shown in the above table, in the original RCA standard cleaning process, two kinds of acid solutions need to be added during pickling. After converting the two kinds of acid solutions into the mixed acid solution described in the application examples, and combining with the ultrasonic wave and deionized water rinsing of the silicon wafer in the examples, the final test results meet the cleaning requirements, so that the mixed acid solution of the application can replace the existing two kinds of acid solutions. In this way, only one step of pickling can achieve the original cleaning effect, while reducing the pickling steps, reducing the use of chemical agents, reducing the cost, and ensuring the cleaning quality. Figures 1-6 As shown in the above table, in the original RCA standard cleaning process, two kinds of acid solutions need to be added during pickling. After converting the two kinds of acid solutions into the mixed acid solution described in the application examples, and combining with the ultrasonic wave and deionized water rinsing of the silicon wafer in the examples, the final test results meet the cleaning requirements, so that the mixed acid solution of the application can replace the existing two kinds of acid solutions. In this way, only one step of pickling can achieve the original cleaning effect, while reducing the pickling steps, reducing the use of chemical agents, reducing the cost, and ensuring the cleaning quality.

[0071] Among them, the control system includes a temperature control system, which controls the temperature of the liquid in the cleaning tank to achieve the required cleaning temperature. The lighting system is equipped with double light daylight lamps at the top of the working area to enable the operator to clearly observe the cleaning situation during the cleaning process. It also includes an exhaust and air supply system, which can adjust the air volume to exhaust the waste gas and acid mist generated during the cleaning process, and plays a safety protection role for the operator. The top of the device is provided with a purification air supply device to ensure air purification and air circulation inside the device.

[0072] The skeleton and shell of the device body 100 play a supporting and protecting role for the internal structure of the device. At the same time, considering that the device needs to work in an acid corrosion environment for a long time, it needs to have corresponding corrosion resistance. And the lower part of the device body 100 has pipelines for connecting various cleaning tanks, liquid preparation and supply systems, liquid discharge systems, etc. And all the process tanks, pipelines and valve parts will have clear labels for easy operation and maintenance. Among them, the chemical liquid pipeline needs to use corrosion-resistant PFA pipe, and the pure water pipeline uses white NPP spray pipe, etc. The generated chemical corrosion waste liquid and flushing wastewater need to be discharged through a special pipeline.

[0073] The deionized pure water is in the immersion tank 31, the mixed acid solution is in the pickling tank 32, the side wall of the rinsing tank 33 is connected with the liquid supply system and the liquid discharge system through the spraying device, the deionized water is sprayed for rinsing, and the ultrasonic tank 34 is connected with the ultrasonic device to further clean. During the cleaning process, the control system automatically adjusts the liquid supply system and the liquid discharge system to replace the solution in the several cleaning tanks. During use, the silicon wafer is loaded in the cleaning container 1, the cleaning container 1 is driven by the lifting mechanism 2 to enter different cleaning tanks in sequence according to the above cleaning process, and waste liquid inevitably drops during the transfer of the cleaning container 1. At this time, the liquid receiving plate 41 driven by the mechanical arm 4 is always horizontally located at the bottom of the liquid receiving plate 41, the falling waste liquid is received by the liquid receiving plate 41, and the waste liquid is prevented from falling and polluting the workbench.

[0074] The liquid receiving plate 41 can also be brought into different cleaning tanks by the mechanical arm 4 to be cleaned by deionized water. After the work is completed, the liquid receiving plate 41 is preferably cleaned in the immersion tank 31 and the rinsing tank 33, and is automatically returned to the side wall of the work cabin and vertically attached to the side wall after cleaning, without interfering with other operations of the work cabin. The lifting mechanism 2 and the mechanical arm 4 are high-speed transfer devices, which can ensure the overall cleaning efficiency.

[0075] As shown in Figure 6 , the liquid receiving plate 41 is in a horizontal state and is in a downwardly recessed arc structure. In order to prevent the cleaning container 1 and the liquid receiving plate 41 from colliding, a certain safety distance is provided between the two, so that when the waste liquid falls from the bottom of the cleaning container 1 to the liquid receiving plate 41, it will be affected by gravity and splash a certain distance around. The arc-shaped structure of the liquid receiving plate 41 can make the splashing waste liquid fall along the four side walls of the liquid receiving plate 41 in a parabolic manner, thereby more conducive to the collection of the falling waste liquid.

[0076] As shown in Figure 5 , the outer edge of the liquid receiving plate 41 is provided with a clamping hole 411, the working end of the mechanical arm 4 is a clamping structure, the clamping structure includes two clamping blocks 42 with adjustable spacing, and the mutually approaching surfaces of the two clamping blocks 42 are both fixed with clamping blocks 421 matched with the clamping hole 411, and the mechanical arm 4 is fixed with the liquid receiving plate 41 by inserting the two clamping blocks 421 into the two ends of the clamping hole 411.

[0077] When the mechanical arm 4 needs to be connected with the liquid receiving plate 41, the distance between the two clamping blocks 42 is increased, the clamping hole 411 on the liquid receiving plate 41 is placed between the two clamping blocks 42 and aligned with the two clamping blocks 421, the distance between the two clamping blocks 42 is reduced, and the two clamping blocks 421 are inserted into the two ends of the clamping hole 411. Thus, the liquid receiving plate 41 is connected with the mechanical arm 4. In this way, the mechanical arm 4 and the liquid receiving plate 41 are detachable structures, which can be conveniently replaced and can adapt to more different cleaning requirements.

[0078] As Figure 4 shown, one embodiment of the cleaning container 1 is a square tube structure, a plurality of parallel strip positioning holes 11 are formed on one side wall of the cleaning container 1, and a plurality of strip insertion holes 12 corresponding to the strip positioning holes 11 are formed on the other three side walls, and the three strip insertion holes 12 corresponding to the same strip positioning hole 11 are integrated.

[0079] The cleaning container 1 is used to hold silicon wafers, and the strip positioning holes 11 have a certain gap that does not hinder the flushing of water flow, the silicon wafers are inserted from the strip insertion holes 12, and stop and position after penetrating into the strip positioning holes 11, and since the three strip insertion holes 12 are integrated, the size of the silicon wafers is not restricted. And in actual cleaning, the cleaning container 1 can be adjusted and placed according to the actual situation, such as the position of the spray, so that the silicon wafers are placed vertically or horizontally, to ensure higher cleaning efficiency. It is worth noting that due to the length limitation of the strip positioning hole 11, when the surface where the strip positioning hole 11 is located is located at the bottom of the cleaning tank, the silicon wafers inside the cleaning container 1 will not penetrate out of the side wall of the cleaning container 1 and contact the working part inside the cleaning tank, preventing the silicon wafers from being damaged.

[0080] In addition, different cleaning containers 1 can be used to adapt to the entire cleaning process according to the number and type of silicon wafers.

[0081] As Figures 1-2 shown, the lifting mechanism 2 is fixed with a lifting hook 21. As Figure 4 shown, the edges of the cleaning container 1 are provided with a hooking groove 13 matched with the lifting hook 21. In this way, the cleaning container 1 placed in any direction can ensure that the side wall of the upper end face has the hooking groove 13, so as to facilitate the lifting of the lifting mechanism 2, and the lifting hook 21 is a double-hook structure with adjustable distance, which hooks the two sides of the cleaning container 1 respectively, and when the double hooks are clamped into the hooking groove 13 and moved up and down or left and right, the cleaning container 1 will not shake, making the whole transfer process more stable, and the whole automatic operation process more perfect. Preferably, the cleaning container 1 and the lifting mechanism 2 can be replaced according to the different silicon wafers.

[0082] The above is only a preferred embodiment of the present application, and is not intended to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. An improved RCA cleaning device, comprising a device main body (100), the device main body (100) comprising a control system, a liquid preparation and supply system, a liquid discharge system and a working cabin, a plurality of cleaning grooves are formed on a workbench of the working cabin, characterized in that ； Also include with the cleaning tank and used for holding the silicon wafer cleaning container (1), the top of the work cabin is fixed with the lifting mechanism (2) can be transferred to different cleaning tank cleaning container (1), the cleaning tank has four, respectively, immersion tank (31), pickling tank (32), flushing tank (33) and ultrasonic tank (34), the side wall of the work cabin is fixed with mechanical arm (4), the working end of the mechanical arm (4) is fixed with liquid receiving plate (41), the liquid receiving plate (41) is always horizontal at the bottom during the transfer of the cleaning container (1); The cleaning container (1) is a square tube structure, a plurality of parallel strip positioning holes (11) are formed in one side wall of the cleaning container (1), a plurality of strip insertion holes (12) corresponding to the strip positioning holes (11) are formed in the other three side walls, and the three strip insertion holes (12) corresponding to the same strip positioning hole (11) are integrated to install silicon wafers of different sizes; The silicon wafer can be inserted into the strip insertion hole (12), and stopped and positioned after penetrating into the strip positioning hole (11); During cleaning, the placement position of the cleaning container (1) can be adjusted, so that the silicon wafer is placed vertically or horizontally; The lifting mechanism (2) is fixed with a lifting hook (21); The edge of the cleaning container (1) is provided with a hooking groove (13) matched with the lifting hook (21), so that when the cleaning container (1) is placed in any direction, the upper end surface side wall position has the hooking groove (13) capable of being lifted by the lifting mechanism (2).

2. The improved RCA cleaning apparatus according to claim 1, wherein The liquid receiving plate (41) is a circular arc structure concave downward when in horizontal state.

3. The improved RCA cleaning apparatus of claim 1, wherein The outer edge of the liquid receiving plate (41) is provided with a clamping hole (411), the working end of the mechanical arm (4) is a clamping structure, the clamping structure includes two clamping blocks (42) with adjustable spacing, and the surfaces of the two clamping blocks (42) approaching each other are fixed with clamping blocks (421) matched with the clamping hole (411), and the mechanical arm (4) is fixed with the liquid receiving plate (41) by inserting the two clamping blocks (421) into the two ends of the clamping hole (411) respectively.

4. The improved RCA cleaning apparatus of claim 1, wherein The lifting hook (21) is a double hook structure with adjustable distance, and the double hooks hook the two sides of the cleaning container (1) respectively.

5. An improved RCA cleaning process, characterized by, The improved RCA cleaning equipment of claim 1 is used for cleaning silicon wafers, including the following steps: S1: put the silicon wafer into the cleaning container (1), and immerse the cleaning container (1) in deionized water; S2: take out the cleaning container (1) and transfer it to a mixed acid solution, immerse it at-10℃~-5℃ for 40s~60s; S3: take out the cleaning container (1) from the mixed acid solution, rinse the silicon wafer with deionized water until all chemicals are rinsed clean; S4: transfer the cleaning container (1) to an ultrasonic cleaner, clean at a cleaning frequency of 28KHZ~40KHZ for 200s~300s; S5: take out the cleaning container (1) and take out the silicon wafer and put it into a dryer for drying treatment until there is no water residue on the surface of the silicon wafer. The mixed acid solution comprises HNO3 with a concentration of 65-68%, HF with a concentration of 40-50%, CH3COOH with a concentration of 95-98%, and H2SO4 with a concentration of 95-98%, and the volume ratio of the four is 3:1:1:3; The CH3COOH can be adsorbed on the hydrophobic surface of the silicon wafer to reduce the surface energy of the silicon wafer, so that the mixed acid solution can spread on the surface of the silicon wafer; The CH3COOH can form a protective film on the surface of the silicon wafer, which is used to prevent the silicon wafer from being contaminated by pollutants in the surrounding environment.

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