Sapphire substrate cleaning device
By combining an electrolysis device and a circulating pump, the problems of high-temperature heating and frequent cleaning solution replacement in sapphire substrate cleaning are solved, achieving efficient cleaning at room temperature and long service life of the cleaning solution, while reducing energy consumption and waste discharge.
Patent Information
- Application Number
- CN202520292297.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-24
- Publication Date
- 2026-02-10
- Estimated Expiration
- 2035-02-24
AI Technical Summary
Existing sapphire substrate cleaning methods require high-temperature heating and frequent replacement of cleaning solutions, resulting in high energy consumption, large amounts of waste liquid discharge, and short service life of the cleaning solution.
An electrolytic device is used to electrochemically electrolyze the cleaning solution to form a high-potential electrolytic cleaning solution. This solution is then used to clean sapphire substrates at room temperature. After use, the cleaning solution is electrolyzed again by a circulating pump to restore its oxidation properties and extend its service life.
It achieves the same cleaning effect as high-temperature heating cleaning at room temperature, reducing the frequency of cleaning fluid replacement and waste liquid discharge, and reducing energy consumption and hydrogen peroxide usage.
Smart Images
Figure CN223888600U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of semiconductor manufacturing technology, and in particular to a sapphire substrate cleaning device. Background Technology
[0002] With the increasing maturity of LED manufacturing processes and the continuous decrease in production costs, its application scope and market size are constantly expanding. However, GaN, the epitaxial material for LEDs, cannot be directly synthesized due to its unique physicochemical properties and must be grown on a specific substrate material. Currently, the mainstream substrate material on the market is patterned sapphire substrate (PSS), with a penetration rate of over 95% in LED substrate applications. The growth of GaN epitaxial layers places high demands on the surface cleanliness of the PSS substrate, and the surface cleanliness of the sapphire wafer is also highly demanding during PSS substrate fabrication. Therefore, controlling the surface cleanliness of the PSS substrate during its patterning process and before epitaxial growth is particularly important.
[0003] Currently, the main method for cleaning sapphire substrates involves immersing them in a cleaning tank containing a cleaning solution. The commonly used cleaning solution is SPM solution, which is prepared by mixing sulfuric acid and hydrogen peroxide in a specific ratio. The carboxylic acid formed by the sulfuric acid and hydrogen peroxide in the SPM solution has strong oxidizing and dehydrating properties, breaking down the carbon-hydrogen bonds of organic matter and oxidizing organic contaminants into CO2 and H2O, thus removing the organic matter. It can also oxidize some metals, dissolving them in the cleaning solution. To achieve better cleaning results, the cleaning solution needs to be heated during the cleaning process, maintaining the temperature between 110 and 140°C. Hydrogen peroxide is continuously consumed during cleaning, requiring constant replenishment. Furthermore, as the number of cleaning batches increases, the concentration of sulfuric acid decreases, and the cleaning capacity gradually declines. Therefore, to ensure cleaning effectiveness, the cleaning solution needs to be replaced periodically. This limits the number of sapphire substrates that can be cleaned per batch, and frequent replacement of the sulfuric acid solution generates a large amount of waste sulfuric acid, which requires hazardous waste treatment. Therefore, it is of great significance to develop a sapphire substrate cleaning device that can extend the service life of the cleaning solution and does not require heating during the cleaning process. Utility Model Content
[0004] The technical problem to be solved by this utility model is to provide a sapphire substrate cleaning device that can extend the service life of the cleaning solution and does not require heating when cleaning the sapphire substrate, thereby reducing waste liquid discharge and energy consumption.
[0005] To solve the above-mentioned technical problems, this utility model provides a sapphire substrate cleaning device, including a cleaning tank, an electrolysis device and a filter;
[0006] The electrolysis device is used to electrolyze the original cleaning solution and the used cleaning solution, so that the original cleaning solution and the used cleaning solution respectively form electrolytic cleaning solutions; the original cleaning solution is a sulfuric acid solution or an SPM solution, and the used cleaning solution is the solution obtained after the electrolytic cleaning solution cleans the sapphire substrate to be cleaned.
[0007] The output end of the electrolysis device is connected to the input end of the filter, and the output end of the filter is connected to the input end of the cleaning tank, so that the electrolytic cleaning solution formed in the electrolysis device flows into the cleaning tank. The filter is used to filter the electrolytic cleaning solution formed in the electrolysis device. The output end of the cleaning tank is connected to the return end of the electrolysis device, so that the cleaning solution after use flows into the electrolysis device.
[0008] As an improvement to the above technical solution, the sapphire substrate cleaning device further includes a first circulation pump and a second circulation pump;
[0009] The output end of the electrolysis device is connected to the input end of the first circulating pump, and the output end of the first circulating pump is connected to the input end of the filter.
[0010] The output end of the cleaning tank is connected to the input end of the second circulation pump, and the output end of the second circulation pump is connected to the return end of the electrolysis device.
[0011] As an improvement to the above technical solution, the electrolysis device includes an electrolytic cell and an anode plate and a cathode plate installed in the electrolytic cell. The anode plate is electrically connected to the positive terminal of an external power source, and the cathode plate is electrically connected to the negative terminal of an external power source.
[0012] The output end of the electrolytic cell is connected to the input end of the first circulating pump, and the output end of the second circulating pump is connected to the return end of the electrolytic cell.
[0013] As an improvement to the above technical solution, the cleaning tank is installed inside the electrolytic cell, and the anode plate and cathode plate are located on both sides of the cleaning tank.
[0014] As an improvement to the above technical solution, the sapphire substrate cleaning device further includes a sealing cover, which is annular in shape;
[0015] The top of the cleaning tank protrudes beyond the top of the electrolytic cell, and the sealing cover is placed on the top of the electrolytic cell and sleeved on the outside of the cleaning tank.
[0016] As an improvement to the above technical solution, the sapphire substrate cleaning device further includes a gas recovery mechanism, and the sealing cover is provided with a gas output end, which is connected to the gas recovery mechanism.
[0017] As an improvement to the above technical solution, the connection between the sealing cover and the cleaning tank is sealed, and the connection between the sealing cover and the electrolytic cell is also sealed.
[0018] As an improvement to the above technical solution, the sapphire substrate cleaning device further includes a waste liquid recovery mechanism, wherein the output end of the second circulation pump is connected to the input end of the waste liquid recovery mechanism.
[0019] As an improvement to the above technical solution, the sapphire substrate cleaning device further includes a first control valve and a second control valve;
[0020] The first control valve is provided on the connecting pipe between the output end of the second circulating pump and the return end of the electrolytic cell, and the second control valve is provided on the connecting pipe between the output end of the second circulating pump and the input end of the waste liquid recovery mechanism.
[0021] The present invention offers the following advantages: By incorporating an electrolysis device into the sapphire substrate cleaning apparatus, the original cleaning solution is electrochemically electrolyzed at room temperature before cleaning. This electrolysis generates a high potential in the resulting solution, forming an electrolytic cleaning solution. At this high potential, the electrolytic cleaning solution exhibits strong oxidizing properties. Using this solution, the sapphire substrate can be cleaned at room temperature without heating, achieving the same or even better cleaning effect as conventional SPM solutions after high-temperature heating. Furthermore, since the output end of the cleaning tank is connected to the return end of the electrolysis device, when the cleaning capacity of the electrolytic cleaning solution in the cleaning tank drops to a specified value, the used solution can be transferred back to the electrolysis device for re-electrolysis, restoring its strong oxidizing properties. This allows it to be reused for cleaning the sapphire substrate without the need for replacement, thus extending the service life of the cleaning solution, significantly reducing the frequency of replacement, and consequently reducing wastewater discharge. Furthermore, since the sapphire substrate cleaning device of this invention can generate strong oxidizing properties in the solution through electrolysis, there is no need to continuously replenish hydrogen peroxide to maintain the oxidizing properties of the solution during the cleaning process, which can reduce the amount of hydrogen peroxide used. Attached Figure Description
[0022] Figure 1 This is a schematic diagram of the sapphire substrate cleaning device in one embodiment of the present invention;
[0023] The components include: cleaning tank 1, electrolysis device 2, filter 3, first circulation pump 4, second circulation pump 5, sealing cover 6, gas recovery mechanism 7, waste liquid recovery mechanism 8, cleaning tank 1, electrolysis tank 21, anode plate 22, cathode plate 23, first control valve 91, and second control valve 92. Detailed Implementation
[0024] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings. This utility model can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this utility model.
[0025] In the description of this utility model, it should be understood that the terms "upper", "lower", "left", "right", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.
[0026] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
[0027] like Figure 1 As shown, this embodiment discloses a sapphire substrate cleaning apparatus, including a cleaning tank 1, an electrolysis device 2, and a filter 3;
[0028] The electrolysis device 2 is used to electrolyze the original cleaning solution and the used cleaning solution, so that the original cleaning solution and the used cleaning solution respectively form electrolytic cleaning solutions; the original cleaning solution is a sulfuric acid solution or an SPM solution, and the used cleaning solution is the solution obtained after the electrolytic cleaning solution cleans the sapphire substrate to be cleaned.
[0029] The output end of the electrolysis device 2 is connected to the input end of the filter 3, and the output end of the filter 3 is connected to the input end of the cleaning tank 1, so that the electrolytic cleaning solution formed in the electrolysis device flows into the cleaning tank. The electrolytic cleaning solution is used to clean the sapphire substrate to be cleaned in the cleaning tank 1. The filter 3 is used to filter the electrolytic cleaning solution formed in the electrolysis device 2 to remove impurities such as metals from the electrolytic cleaning solution, thereby improving the cleaning effect of the electrolytic cleaning solution. The electrolytic cleaning solution enters the cleaning tank 1 after filtration.
[0030] The output end of the cleaning tank 1 is connected to the return end of the electrolysis device 2, so that the used cleaning solution in the cleaning tank flows back into the electrolysis device 2 for electrolysis and reforms the electrolytic cleaning solution.
[0031] It is worth noting that existing technologies using SPM solution to clean sapphire substrates require temperature control between 110 and 140°C. This is primarily to enhance the oxidizing power of the SPM solution and accelerate the chemical reaction rate, thereby more effectively oxidizing and decomposing organic matter and other impurities on the sapphire substrate surface, transforming them into easily removable substances such as carbon dioxide and water. This invention, by incorporating an electrolysis device 2 into the sapphire substrate cleaning apparatus, electrochemically electrolyzes the original cleaning solution at room temperature before cleaning. This generates a high potential in the electrolyzed solution, forming an electrolytic cleaning solution. At this high potential, the electrolytic cleaning solution possesses extremely strong oxidizing properties. Using this electrolytic cleaning solution, the sapphire substrate can be cleaned at room temperature, achieving the same or even better cleaning effect as conventional SPM solutions after high-temperature heating, without the need for heating. Furthermore, since the output end of the cleaning tank 1 and the return end of the electrolysis device 2 are connected, when the cleaning capacity of the electrolytic cleaning solution in the cleaning tank 1 drops to a specified value, the used electrolytic cleaning solution (i.e., the used cleaning solution) can be transported to the electrolysis device 2. The used cleaning solution is then electrolyzed again by the electrolysis device 2 to restore its strong oxidizing properties, allowing it to continue to be used for cleaning the sapphire substrate without the need to replace it with new cleaning solution. This extends the service life of the cleaning solution, significantly reduces the frequency of cleaning solution replacement, and consequently reduces the amount of waste liquid discharged. In addition, since the sapphire substrate cleaning device of this invention can generate strong oxidizing properties in the solution through electrolysis, there is no need to continuously replenish hydrogen peroxide to maintain the oxidizing properties of the solution during the cleaning process, thus reducing the amount of hydrogen peroxide used.
[0032] It should be noted that when the sapphire substrate cleaning device of this invention starts working, the original cleaning solution needs to be electrolyzed in the electrolysis device 2 to form an electrolytic cleaning solution. This electrolytic cleaning solution is then transported to the cleaning tank 1, where the sapphire substrate to be cleaned is cleaned using the electrolytic cleaning solution. In subsequent cleaning processes, on the one hand, the solutions in the cleaning tank 1 and the electrolysis device 2 can circulate, achieving simultaneous cleaning and electrolysis; on the other hand, once the cleaning capacity of the electrolytic cleaning solution in the cleaning tank 1 decreases to a preset value, all the used electrolytic cleaning solution (i.e., the used cleaning solution) can be transported back to the electrolysis device 2 for electrolysis, restoring its strong oxidizing properties. Then, the re-electrolyzed electrolytic cleaning solution is transported back to the cleaning tank 1 to continue cleaning a new batch of sapphire substrates.
[0033] Preferably, the sulfuric acid solution is concentrated sulfuric acid. In an optional embodiment, the concentration of the concentrated sulfuric acid is 95% to 99%.
[0034] Specifically, the SPM solution is prepared by mixing sulfuric acid solution and hydrogen peroxide in a certain proportion. Commercially available products can be used, or the solution can be prepared directly according to conventional proportions in the art. In an optional embodiment, the volume ratio of H2SO4 solution (98% concentration) to H2O2 solution (30% concentration) in the SPM solution is 4:1 to 6:1.
[0035] Specifically, the filter 3 of this invention is selected to be acid-resistant and corrosion-resistant. Preferably, the filter element of the filter 3 can be a polytetrafluoroethylene (PTFE) filter element or a ceramic filter element.
[0036] In one embodiment, the sapphire substrate cleaning apparatus further includes a first circulation pump 4 and a second circulation pump 5;
[0037] The output end of the electrolysis device 2 is connected to the input end of the first circulation pump 4, and the output end of the first circulation pump 4 is connected to the input end of the filter 3. The electrolytic cleaning solution formed after electrolysis in the electrolysis device 2 is first transported to the cleaning tank 1 through the filter 3 by the first circulation pump 4, so as to clean the sapphire substrate to be cleaned in the cleaning tank 1.
[0038] The output end of the cleaning tank 1 is connected to the input end of the second circulation pump 5, and the output end of the second circulation pump 5 is connected to the return end of the electrolysis device 2. The used cleaning liquid in the cleaning tank 1 is transported to the electrolysis device 2 through the second circulation pump 5, so that the used cleaning liquid is electrolyzed again in the electrolysis device 2, so that it generates a high potential again, has strong oxidizing properties, and reforms the electrolytic cleaning liquid.
[0039] In one embodiment, the electrolysis device 2 includes an electrolytic cell 21 and an anode plate 22 and a cathode plate 23 installed within the electrolytic cell 21. The anode plate 22 is electrically connected to the positive terminal of an external power supply, and the cathode plate 23 is electrically connected to the negative terminal of an external power supply, thereby enabling the electrolysis of the original cleaning solution and the used cleaning solution separately within the electrolytic cell 21. During electrolysis, the anode plate 22 is connected to the positive terminal of the power supply. When current flows through it, the metal atoms on the anode plate 22 lose electrons and become metal ions that enter the solution. Simultaneously, the anions in the solution also accept electrons on the anode plate 22, undergoing an oxidation reaction, thereby enhancing the oxidizing power of the solution.
[0040] The output end of the electrolytic cell 21 is connected to the input end of the first circulation pump 4. Since the output end of the first circulation pump 4 is connected to the input end of the filter 3, and the output end of the filter 3 is connected to the input end of the cleaning tank 1, the electrolytic cleaning solution formed after electrolysis in the electrolytic cell 21 is first filtered by the filter 3 and then transported to the cleaning tank 1 by the first circulation pump 4, so as to clean the sapphire substrate to be cleaned in the cleaning tank 1.
[0041] The output end of the second circulation pump 5 is connected to the return end of the electrolytic cell 21. The used cleaning solution in the cleaning tank 1 is transported to the electrolytic cell 21 through the second circulation pump 5, so that the used cleaning solution is electrolyzed again in the electrolytic cell 21, so that it generates a high potential again, has strong oxidizing properties, and reforms the electrolytic cleaning solution.
[0042] Preferably, the main material of the anode plate includes any one or more combinations of titanium, stainless steel and nickel alloys, and the anode plates made of these materials have good electrical conductivity, mechanical strength and corrosion resistance.
[0043] In one embodiment, the cleaning tank 1 is installed inside the electrolytic cell 21, and the anode plate 22 and cathode plate 23 are located on both sides of the cleaning tank 1, so that the cleaning tank 1 and the electrolytic cell 21 are integrated together, making the structure of the entire sapphire substrate cleaning device more compact, reducing the footprint of the equipment, and reducing the number of connecting pipes between the equipment, thus reducing the complexity of the equipment.
[0044] In one embodiment, the cleaning tank 1 is installed at the internal center of the electrolysis device 2.
[0045] In one embodiment, the sapphire substrate cleaning apparatus further includes a sealing cover 6, which is annular in shape.
[0046] The top of the cleaning tank 1 protrudes from the top of the electrolytic tank 21, and the sealing cover 6 is placed on the top of the electrolytic tank 21 and sleeved on the outside of the cleaning tank 1.
[0047] In one embodiment, the sapphire substrate cleaning apparatus further includes a gas recovery mechanism 7. The sealing cover 6 is provided with a gas output end, and the gas output end of the sealing cover 6 is connected to the gas recovery mechanism 7, so that the gas generated by electrolysis in the electrolytic cell is introduced into the gas recovery mechanism.
[0048] Specifically, during electrolysis, an electrochemical reaction generates gases such as oxygen and hydrogen. The opening of the electrolytic cell 21 is sealed by a sealing cap 6. Simultaneously, the electrolytic cell 21 is connected to the gas recovery mechanism 7 via the gas output terminal 61, allowing the recovery of the gases generated during electrolysis. Furthermore, in practical applications, a blower or vacuum pump can be added to extract other gases from the electrolytic cell 21 to the gas recovery mechanism 7.
[0049] Preferably, the gas recovery mechanism 7 can be a gas storage tank, a gas separator, or a machine for processing gas, such as a burner.
[0050] In one embodiment, the connection between the sealing cover 6 and the cleaning tank 1 is sealed, and the connection between the sealing cover 6 and the electrolytic tank 21 is also sealed.
[0051] Specifically, sealing can be achieved by setting sealing rings at the connection between the sealing cover 6 and the cleaning tank 1, and at the connection between the sealing cover 6 and the electrolytic tank 21.
[0052] In one embodiment, the sapphire substrate cleaning apparatus further includes a waste liquid recovery mechanism 8, wherein the output end of the second circulation pump 5 is connected to the input end of the waste liquid recovery mechanism 8.
[0053] It is worth noting that although the sapphire substrate cleaning device of this invention can extend the service life of the cleaning solution and significantly reduce the frequency of cleaning solution replacement, the cleaning solution will still experience some loss after prolonged use and electrolysis. When the volume of the cleaning solution is insufficient to completely submerge the sapphire substrate, it is recommended to replace it with a new batch of solution. By incorporating a waste liquid recovery mechanism 8 into the sapphire substrate cleaning device, the waste cleaning solution (i.e., waste liquid) can be transported to the waste liquid recovery mechanism 8 via the second circulation pump 5, which facilitates subsequent waste liquid treatment.
[0054] Preferably, the waste liquid recovery mechanism 8 can be a buffer tank for temporarily storing waste cleaning fluid, or it can be used to treat waste liquid.
[0055] In one embodiment, the sapphire substrate cleaning apparatus further includes a first control valve 91 and a second control valve 92;
[0056] The first control valve 91 is provided on the connecting pipe between the output end of the second circulation pump 5 and the return end of the electrolytic cell 21, and the second control valve 92 is provided on the connecting pipe between the output end of the second circulation pump 5 and the input end of the waste liquid recovery mechanism 8. The flow direction of the cleaning liquid flowing out of the cleaning tank 1 is controlled by the first control valve and the second control valve.
[0057] The technical principles of this utility model have been described above with reference to specific embodiments. These descriptions are merely for explaining the principles of this utility model and should not be construed as limiting the scope of protection of this utility model in any way. Based on this explanation, those skilled in the art can readily conceive of other specific embodiments of this utility model without any inventive effort, and these embodiments will all fall within the scope of protection of this utility model.
Claims
1. A sapphire substrate cleaning apparatus, characterized in that, Includes a cleaning tank, an electrolysis unit, and a filter; The electrolysis device is used to electrolyze the original cleaning solution and the used cleaning solution, so that the original cleaning solution and the used cleaning solution respectively form electrolytic cleaning solutions; The original cleaning solution is a sulfuric acid solution or an SPM solution, and the used cleaning solution is the solution obtained after cleaning the sapphire substrate to be cleaned with the electrolytic cleaning solution. The output end of the electrolysis device is connected to the input end of the filter, and the output end of the filter is connected to the input end of the cleaning tank, so that the electrolytic cleaning solution formed in the electrolysis device flows into the cleaning tank. The filter is used to filter the electrolytic cleaning solution formed in the electrolysis device. The output end of the cleaning tank is connected to the return end of the electrolysis device, so that the cleaning solution after use flows into the electrolysis device.
2. The sapphire substrate cleaning apparatus according to claim 1, characterized in that, The sapphire substrate cleaning device also includes a first circulation pump and a second circulation pump; The output end of the electrolysis device is connected to the input end of the first circulating pump, and the output end of the first circulating pump is connected to the input end of the filter. The output end of the cleaning tank is connected to the input end of the second circulation pump, and the output end of the second circulation pump is connected to the return end of the electrolysis device.
3. The sapphire substrate cleaning apparatus according to claim 2, characterized in that, The electrolysis device includes an electrolytic cell and an anode plate and a cathode plate installed in the electrolytic cell. The anode plate is electrically connected to the positive terminal of an external power source, and the cathode plate is electrically connected to the negative terminal of an external power source. The output end of the electrolytic cell is connected to the input end of the first circulating pump, and the output end of the second circulating pump is connected to the return end of the electrolytic cell.
4. The sapphire substrate cleaning apparatus according to claim 3, characterized in that, The cleaning tank is installed inside the electrolytic cell, and the anode plate and cathode plate are located on both sides of the cleaning tank.
5. The sapphire substrate cleaning apparatus according to claim 4, characterized in that, The sapphire substrate cleaning apparatus also includes a sealing cover, which is annular in shape. The top of the cleaning tank protrudes beyond the top of the electrolytic cell, and the sealing cover is placed on the top of the electrolytic cell and sleeved on the outside of the cleaning tank.
6. The sapphire substrate cleaning apparatus according to claim 5, characterized in that, The sapphire substrate cleaning device also includes a gas recovery mechanism. The sealing cover is provided with a gas output end, and the gas output end of the sealing cover is connected to the gas recovery mechanism, so that the gas generated by electrolysis in the electrolytic cell is introduced into the gas recovery mechanism.
7. The sapphire substrate cleaning apparatus according to claim 5, characterized in that, The connection between the sealing cover and the cleaning tank is sealed, and the connection between the sealing cover and the electrolytic cell is also sealed.
8. The sapphire substrate cleaning apparatus according to claim 4, characterized in that, The sapphire substrate cleaning device also includes a waste liquid recovery mechanism, wherein the output end of the second circulation pump is connected to the input end of the waste liquid recovery mechanism.
9. The sapphire substrate cleaning apparatus according to claim 8, characterized in that, The sapphire substrate cleaning device also includes a first control valve and a second control valve. The first control valve is provided on the connecting pipe between the output end of the second circulating pump and the return end of the electrolytic cell, and the second control valve is provided on the connecting pipe between the output end of the second circulating pump and the input end of the waste liquid recovery mechanism.