Semiconductor wafer cleaning system and semiconductor wafer cleaning method
By integrating a cleaning fluid supply system and a cleaning and drying integrated chamber into a semiconductor wafer cleaning system, the problem of unstable wafer surface temperature during supercritical carbon dioxide cleaning is solved, achieving efficient cleaning and drying and avoiding the appearance of cleaning marks.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- BEIJING SEMICORE MICROELECTRONICS EQUIPMENT CO LTD
- Filing Date
- 2026-01-30
- Publication Date
- 2026-05-12
AI Technical Summary
During the supercritical carbon dioxide cleaning process of wafers, the temperature of the wafer surface is unstable, which leads to the appearance of cleaning marks.
Design a semiconductor wafer cleaning system, including a cleaning fluid supply system and an integrated cleaning and drying chamber. By combining the chamber shell, wafer support module, cleaning fluid spray pipe and drying heating pipe, cleaning and drying can be carried out in one chamber, maintaining the stable ambient temperature of the wafer surface and keeping the supercritical carbon dioxide state stable.
It improves cleaning efficiency, avoids the appearance of cleaning marks on the wafer surface, and reduces equipment size and cost.
Smart Images
Figure CN122028679A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of semiconductor manufacturing technology. Specifically, it relates to a semiconductor wafer cleaning system and a semiconductor wafer cleaning method. Background Technology
[0002] In semiconductor manufacturing, traditional cleaning and drying processes are insufficient to meet the requirements of fine circuit patterns, failing to effectively achieve non-destructive cleaning of wafers. Due to the high surface tension of water, when the wafer surface film material is hydrophobic, it is difficult for the solution to penetrate deep into high aspect ratio electronic circuit patterns, directly affecting the effectiveness of liquid phase cleaning. When the linewidth is below 14nm, the surface tension during wafer surface drying after wet cleaning can easily lead to the collapse of high aspect ratio patterns. This is especially true when cleaning photoresist on the surface of low-k films used for interlayer interconnects. Low-k materials are often porous, and the device structure is easily damaged by plasma ashing and subsequent liquid phase cleaning. Furthermore, prolonged immersion in water-based solvents and water absorption of low-k films increases their effective dielectric constant, leading to increased interconnect resistance and capacitance. Supercritical carbon dioxide (SCO)... SC CO2 has a high solubility for photoresist. Placing a wafer in supercritical CO2 allows photoresist contaminants on the wafer to dissolve in the supercritical CO2 fluid. Furthermore, supercritical fluids possess gas-like diffusivity and liquid-like dissolving power, enabling them to penetrate well into minute spaces and pores. SC CO2 fluid processing ensures that even very fine structures can be effectively cleaned, and in the supercritical state, there is no obvious liquid-gas interface, which greatly reduces the impact of surface tension and effectively protects the high aspect ratio patterns on the wafer surface from collapse. However, because the cleaning process typically involves multiple chambers, the instability of the supercritical fluid (or the difficulty in maintaining the supercritical state) causes instability in the wafer surface temperature during its movement between chambers. SC The supercritical state of CO2 is difficult to maintain, making it easy for cleaning marks to be left on the wafer surface.
[0003] Therefore, a solution is needed to address the problem that the unstable ambient temperature on the wafer surface during supercritical carbon dioxide cleaning makes it easy for cleaning marks to be left on the wafer surface. Summary of the Invention
[0004] Therefore, this application provides a semiconductor wafer cleaning system and a semiconductor wafer cleaning method to solve the problem that the unstable ambient temperature on the wafer surface during supercritical carbon dioxide cleaning makes it easy for cleaning marks to be left on the wafer surface.
[0005] In one aspect of this application, a semiconductor wafer cleaning system is provided, comprising:
[0006] Cleaning fluid supply system and integrated cleaning and drying chamber; The cleaning fluid supply system is suitable for supplying supercritical carbon dioxide cleaning fluid to the integrated cleaning and drying chamber; The integrated cleaning and drying chamber includes: The chamber shell surrounds a closed chamber space and is connected to the cleaning fluid supply system; A wafer support module is suitable for fixing the wafer to be cleaned and dried in the chamber space and for driving the wafer to rotate. A plurality of cleaning fluid spray pipes are distributed on at least one side of the inner wall of the chamber shell, and are adapted to supply supercritical carbon dioxide cleaning fluid to the wafer spray cleaning fluid supply system. A plurality of drying heating tubes are distributed on at least one side of the inner wall of the chamber shell, which is suitable for controlling the temperature in the chamber space to maintain the stability of the supercritical state of carbon dioxide. The main heating element is adapted to heat the ambient temperature within the chamber space to dry the wafer after cleaning.
[0007] The semiconductor wafer cleaning system provided in this application, through the arrangement of a chamber shell, a wafer support module inside the chamber shell, a cleaning fluid spray pipe, and a drying heating pipe, enables the wafer cleaning and drying steps to be performed within a single chamber. This maintains a stable surface temperature on the wafer during the cleaning process, preventing significant temperature changes due to transfer, thereby ensuring the cleaning process continues smoothly. SC CO2 is stable in its supercritical state, so it is highly efficient at cleaning and does not easily leave marks on the wafer surface.
[0008] In some embodiments of this application, the drying heating tube is nested within the outer wall of the cleaning liquid spray tube; the opening of the cleaning spray tube extends beyond the opening of the drying heating tube. The cleaning fluid spray pipes and drying heating pipes are evenly distributed on their respective surfaces, with multiple concentric rings distributed from the center outwards. The cleaning fluid spray pipes in each concentric ring are evenly distributed; the number of concentric rings is greater than or equal to 2; the cleaning fluid spray pipes and drying heating pipes are also provided at the center of the surface on which the cleaning fluid spray pipes and drying heating pipes are located.
[0009] The semiconductor wafer cleaning system provided in this application achieves uniform distribution of the cleaning solution spray pipes and drying heating pipes within the chamber through the aforementioned distribution method. SC The uniform distribution of CO2, along with the uniform distribution of heating positions, helps maintain a stable and uniform temperature within the chamber, thereby maintaining... SC CO2 is stable in its supercritical state.
[0010] In some embodiments of this application, the wafer support module is a bracket-type chuck module, including: The grippers are designed to hold and clamp the wafer, and are relatively distributed. The support frame includes a connecting frame and a support column. The connecting frame connects the gripper and the support column. The support column is adapted to rotate and drive the connecting frame and the gripper to rotate, thereby driving the wafer to rotate. The connecting frame is a distributed linkage structure with space between adjacent linkages, exposing the surface of the wafer facing the support frame.
[0011] The semiconductor wafer cleaning system provided in this application has a wafer support module that is a bracket-type chuck module. The support frame minimizes the obstruction of the wafer's surface facing the support frame, thereby maintaining the wafer's fixation while maximizing the cleaning effect of the cleaning solution spraying from the cleaning solution spray pipe on that side.
[0012] In some embodiments of this application, the cleaning fluid supply system includes a balancing mixing chamber adapted to mix carbon dioxide and other components, and to heat and pressurize the mixture to form a supercritical carbon dioxide cleaning fluid. Other components include solubilizers, surfactants, and other additives; The cleaning fluid supply system also includes a carbon dioxide supply source, a cosolvent supply source, a surfactant supply source, and other auxiliary agent supply sources, which are connected to the equilibrium mixing chamber through supply pipelines. Each supply pipeline is equipped with a shut-off valve.
[0013] The semiconductor wafer cleaning system provided in this application, through the setting of a balanced mixing chamber, allows supercritical carbon dioxide to be fully mixed with other components to form a supercritical carbon dioxide cleaning agent, which, in addition to simple rinsing, can also have other beneficial effects on cleaning and improve cleaning efficiency.
[0014] In some embodiments of this application, the equilibrium mixing chamber includes a mixing tank and a circulation pipeline, the circulation pipeline is equipped with a circulation pump, and the mixing tank is suitable for heating and pressurization; Other components are suitable for circulating in the equilibrium mixing chamber through circulation pipelines and circulation pumps, and are mixed with carbon dioxide in the mixing tank under heating and pressurization to form a supercritical carbon dioxide cleaning solution. The balanced mixing chamber is connected to the integrated cleaning and drying chamber, and is also connected to the cleaning liquid spray pipe. The pipeline connected to the integrated cleaning and drying chamber is equipped with a throttling valve.
[0015] The semiconductor wafer cleaning system provided in this application improves cleaning efficiency by balancing the mixing tank and circulation pipeline in the mixing chamber, allowing other components to be fully mixed with supercritical carbon dioxide.
[0016] In some embodiments of this application, the semiconductor wafer cleaning system is further provided with a discharge pipeline connected to the integrated cleaning and drying chamber; The discharge line connects to the chamber space and is equipped with a back pressure valve to discharge carbon dioxide from the integrated cleaning and drying chamber when needed.
[0017] In another aspect, this application also provides a semiconductor wafer cleaning method, using the semiconductor wafer cleaning system provided in this application, including the following steps: Cleaning solution preparation: Supercritical carbon dioxide cleaning solution is formed in the cleaning solution supply system; Chamber preparation: The wafer to be cleaned is placed into the integrated cleaning and drying chamber. The space inside the integrated cleaning and drying chamber is vacuumed. Then, the space inside the integrated cleaning and drying chamber is heated and pressurized to make the environment inside the chamber meet the supercritical conditions of supercritical carbon dioxide. The cleaning fluid supply system supplies supercritical carbon dioxide cleaning fluid to the integrated cleaning and drying chamber. The wafer is cleaned by driving it to rotate. The cleaning solution spray pipe sprays supercritical carbon dioxide cleaning solution onto the wafer for cleaning. The drying heating tube maintains the temperature during the cleaning process, keeping the supercritical carbon dioxide in a supercritical state. The cleaning solution supply system supplies supercritical carbon dioxide to the integrated cleaning and drying chamber for drying the wafer. The drying heating tube controls the temperature to maintain the supercritical state of the supercritical carbon dioxide. The main heating component raises the temperature of the space inside the chamber to dry the wafer surface.
[0018] The semiconductor wafer cleaning method and system provided in this application allow the cleaning and drying steps to be performed within a single chamber during the supercritical carbon dioxide cleaning process. This maintains a stable surface temperature on the wafer during cleaning, preventing significant temperature changes due to transfer and thus ensuring the cleaning process continues. SC CO2 is stable in its supercritical state, so it is highly efficient at cleaning and does not easily leave marks on the wafer surface.
[0019] In some embodiments of this application, the step of preparing the cleaning solution includes: To balance the mixing chamber, heating and pressurization are applied to meet the supercritical state requirements of carbon dioxide; Carbon dioxide is supplied to the equilibrium mixing chamber through a carbon dioxide supply source; other components are supplied to the equilibrium mixing chamber through a supply source of other components; the other components circulate in the equilibrium mixing chamber and mix with carbon dioxide under heating and pressurization to form a supercritical carbon dioxide cleaning solution; Other components include solubilizers, surfactants, and other additives.
[0020] In some embodiments of this application, the supercritical carbon dioxide cleaning solution includes a first cleaning solution, a second cleaning solution, and a third cleaning solution with three different components; The process of cleaning a wafer includes at least the following steps: The wafer surface is cleaned with a first cleaning solution to reduce the wafer surface tension and the adsorption force on surface particles; the first cleaning solution is a mixture of supercritical carbon dioxide and surfactant. The wafer surface is cleaned with a second cleaning solution to enhance the solubility of contaminant particles on the wafer surface; the second cleaning solution is a mixture of supercritical carbon dioxide and a co-solvent. The wafer surface is cleaned with a second cleaning solution to rinse away contaminant particles; the third cleaning solution is a mixture of supercritical carbon dioxide and a cleaning agent.
[0021] The semiconductor wafer cleaning method provided in this application uses three supercritical carbon dioxide cleaning solutions with different compositions. First, the first cleaning solution reduces the surface tension of the wafer and decreases the adsorption force on surface particles. Then, the second cleaning solution enhances the solubility of contaminant particles on the wafer surface. Finally, the third cleaning solution rinses and removes contaminant particles from the wafer surface, ensuring excellent cleaning results.
[0022] In some embodiments of this application, in the chamber preparation step, the temperature inside the chamber space of the integrated cleaning and drying chamber is heated to 40°C to 200°C, and the pressure is increased to 8 to 16 MPa, and maintained for at least 10 minutes. In the step of supplying cleaning fluid, the initial flow rate of supercritical carbon dioxide cleaning fluid is 2L / min, maintained for 10s and then adjusted to 5L / min, maintained for 10s and then adjusted to 10L / min, and the fluid is then sprayed into the chamber through the cleaning fluid spray pipe for 10min; the chamber pressure is maintained at 8~16MPa. In the wafer cleaning process, the flow rate of each cleaning solution spray pipe is 1L / min to 4L / min, the pipe opening is 8mm away from the wafer surface, and the wafer rotation speed is 500rpm; the cleaning time of the first cleaning solution is 60s to 120s, the cleaning time of the second cleaning solution is 60s to 120s, and the cleaning time of the third cleaning solution is 60s to 120s; during the cleaning process, the temperature in the integrated cleaning and drying chamber is maintained at 40℃ to 200℃, and the pressure is maintained at 8 to 16MPa. In the wafer drying step, the supercritical carbon dioxide is sprayed into the chamber space by the cleaning solution spray pipe at a flow rate of 1L / min to 4L / min. The temperature in the integrated cleaning and drying chamber space is maintained at 40℃ to 200℃, the pressure is maintained at 8 to 16MPa, and the drying time is 1min to 10min. Attached Figure Description
[0023] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0024] Figure 1 This is a schematic diagram of a semiconductor wafer cleaning system according to an embodiment of this application; Figure 2 This is a schematic diagram of an integrated cleaning and drying chamber in a semiconductor wafer cleaning system according to an embodiment of this application; Figure 3 This is a schematic diagram showing the distribution of the cleaning fluid spray pipe and the drying heating pipe on one side of the inner wall of the chamber shell in a semiconductor wafer cleaning system according to an embodiment of this application. Figure 4 This is a schematic flowchart of a semiconductor wafer cleaning method according to an embodiment of this application. Detailed Implementation
[0025] To address the challenges of maintaining the supercritical state of supercritical fluids in wafer cleaning processes that typically involve multiple chambers, it's important to understand that the movement of these fluids between chambers leads to unstable temperatures on the wafer surface. SC The supercritical state of CO2 is difficult to maintain, which makes it easy to leave cleaning marks on the wafer surface. This application provides a semiconductor wafer cleaning system and a semiconductor wafer cleaning method.
[0026] This application provides a semiconductor wafer cleaning system, comprising: a cleaning fluid supply system and an integrated cleaning and drying chamber; the cleaning fluid supply system is adapted to provide supercritical carbon dioxide cleaning fluid to the integrated cleaning and drying chamber; the integrated cleaning and drying chamber includes: a chamber shell, which surrounds a closed chamber space and is connected to the cleaning fluid supply system; a wafer support module, which is adapted to fix the wafer to be cleaned and dried in the chamber space and to drive the wafer to rotate; a plurality of cleaning fluid spray pipes, which are distributed on at least one side of the inner wall of the chamber shell and are adapted to spray the supercritical carbon dioxide supplied by the cleaning fluid supply system onto the wafer; a plurality of drying heating pipes, which are distributed on at least one side of the inner wall of the chamber shell and are adapted to control the temperature in the chamber space to maintain the supercritical state of carbon dioxide; and a main heating component, which is adapted to heat the ambient temperature in the chamber space to dry the wafer after cleaning.
[0027] This application also provides a semiconductor wafer cleaning method using the semiconductor wafer cleaning system provided in this application, comprising the following steps: cleaning solution preparation, forming a supercritical carbon dioxide cleaning solution in a cleaning solution supply system; chamber preparation, placing the wafer to be cleaned into a cleaning-drying integrated chamber, vacuuming the space inside the cleaning-drying integrated chamber, and then heating and pressurizing the space inside the cleaning-drying integrated chamber to make the environment inside the chamber meet the supercritical conditions of supercritical carbon dioxide; supplying cleaning solution, the cleaning solution supply system supplies supercritical carbon dioxide cleaning solution to the cleaning-drying integrated chamber; cleaning the wafer, driving the wafer to rotate, spraying supercritical carbon dioxide cleaning solution onto the wafer through a cleaning solution spray pipe, and maintaining the temperature during the cleaning process with a drying heating tube to keep the supercritical carbon dioxide in a supercritical state; drying the wafer, the cleaning solution supply system supplies supercritical carbon dioxide to the cleaning-drying integrated chamber, the drying heating tube controls the temperature to maintain the supercritical state of the supercritical carbon dioxide, and the main heating component raises the temperature inside the chamber to dry the wafer surface.
[0028] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. In the description of this application, it should be noted that the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0029] Example 1 refer to Figures 1-2 This embodiment provides a semiconductor wafer cleaning system, including: Cleaning fluid supply system and integrated cleaning and drying chamber 100; The cleaning fluid supply system is adapted to supply supercritical carbon dioxide cleaning fluid to the integrated cleaning and drying chamber 100; The integrated cleaning and drying chamber includes: The chamber shell 1 encloses a closed chamber space and is connected to the cleaning fluid supply system; The wafer support module 5 is adapted to fix the wafer 4 to be cleaned and dried in the cavity space and to drive the wafer 4 to rotate. A plurality of cleaning fluid spray pipes 2 are distributed on at least one side of the inner wall of the chamber shell 1, and are adapted to supply supercritical carbon dioxide cleaning fluid to the wafer spray cleaning fluid supply system. A plurality of drying heating tubes 3 are distributed on at least one side of the inner wall of the chamber shell 1, which are suitable for controlling the temperature in the chamber space to maintain the stability of the supercritical state of carbon dioxide. The main heating element (not shown in the figure) is adapted to heat the ambient temperature within the chamber space to dry the wafer after cleaning.
[0030] The main heating element is positioned anywhere within the chamber housing without interfering with other components, such as on a side wall where the cleaning fluid spray pipe and drying heating pipe are not located. The semiconductor wafer cleaning system provided in this embodiment, through the arrangement of the chamber housing 1, the wafer support module 5 within the chamber housing 1, the cleaning fluid spray pipe 2, and the drying heating pipe 3, allows the wafer cleaning and drying steps to be performed within a single chamber. This maintains a stable surface temperature on the wafer during the cleaning process, preventing significant temperature changes due to transfer, thus ensuring the cleaning process continues. SC CO2 is stable in its supercritical state, so it is highly efficient at cleaning and does not easily leave marks on the wafer surface.
[0031] Further reference Figure 3 In some embodiments of this application, the drying heating tube 3 is nested in the outer wall of the cleaning liquid spray tube 2; the opening of the cleaning spray tube extends beyond the opening of the drying heating tube 3. The cleaning fluid spray pipe 2 and the drying heating pipe 3 are evenly distributed on their respective surfaces, with multiple concentric rings distributed from the center outwards. The cleaning fluid spray pipes in each concentric ring are evenly distributed. The number of concentric rings is greater than or equal to 2. The cleaning fluid spray pipe 2 and the drying heating pipe 3 are also provided at the center of the surface on which the cleaning fluid spray pipe 2 and the drying heating pipe 3 are located.
[0032] The semiconductor wafer cleaning system provided in this embodiment ensures that the cleaning solution spray pipe 2 and the drying heating pipe 3 are evenly distributed within the chamber using the aforementioned distribution method. SC The uniform distribution of CO2, along with the uniform distribution of heating positions, helps maintain a stable and uniform temperature within the chamber, thereby maintaining... SC CO2 is stable in its supercritical state.
[0033] Furthermore, in some embodiments of this application, the wafer support module 5 is a bracket-type chuck module, including: The grippers are designed to hold and clamp the wafer, and are relatively distributed. The support frame includes a connecting frame and a support column. The connecting frame connects the gripper and the support column. The support column is adapted to rotate and drive the connecting frame and the gripper to rotate, thereby driving the wafer to rotate. The connecting frame is a distributed linkage structure with space between adjacent linkages, exposing the surface of the wafer facing the support frame.
[0034] The semiconductor wafer cleaning system provided in this embodiment has a wafer support module 5 that is a bracket-type chuck module. The support frame minimizes the obstruction of the wafer's surface facing the support frame, thereby ensuring the cleaning effect of the cleaning fluid spray pipe 2 spraying cleaning fluid on this side while maintaining wafer fixation.
[0035] Furthermore, in some embodiments of this application, the cleaning fluid supply system includes a balancing mixing chamber adapted to mix carbon dioxide and other components, and heat and pressurize the mixture to form a supercritical carbon dioxide cleaning fluid. Other components include cosolvents, surfactants, and other additives. The cosolvent is an additive that enables supercritical carbon dioxide and other components, as well as particulate impurities, to co-dissolve in the same system, allowing for more thorough contact between the supercritical carbon dioxide and the particulate impurities and other substances requiring cleaning removal. Under typical conditions (35°C, 10–20 MPa), the solubility of supercritical carbon dioxide in the cosolvent is ≥0.5–2 mol%. An example cosolvent can be isopropanol.
[0036] The cleaning fluid supply system also includes a carbon dioxide supply source 310, a cosolvent supply source 320, a surfactant supply source 330, and other auxiliary agent supply sources (not shown in the figure), which are connected to the equilibrium mixing chamber 200 through supply pipelines. Each supply pipeline is equipped with a shut-off valve. A high-pressure injection pump 340 may also be installed on the supply pipeline of the carbon dioxide supply source, through which carbon dioxide is introduced into the equilibrium mixing chamber.
[0037] The semiconductor wafer cleaning system provided in this embodiment, through the setting of the balanced mixing chamber 200, allows supercritical carbon dioxide to be fully mixed with other components to form a supercritical carbon dioxide cleaning agent, which, in addition to simple rinsing, can also have other beneficial cleaning effects and improve cleaning efficiency.
[0038] Furthermore, in some embodiments of this application, the balanced mixing chamber 200 includes a mixing tank and a circulation pipeline, the circulation pipeline is equipped with a circulation pump, and the mixing tank is suitable for heating and pressurization; Other components are suitable for circulating in the equilibrium mixing chamber through circulation pipelines and circulation pumps, and are mixed with carbon dioxide in the mixing tank under heating and pressurization to form a supercritical carbon dioxide cleaning solution. The balanced mixing chamber 200 is connected to the integrated cleaning and drying chamber 100, and is connected to the cleaning liquid spray pipe 2. The pipeline connected to the integrated cleaning and drying chamber is equipped with a throttling valve.
[0039] The semiconductor wafer cleaning system provided in this application improves cleaning efficiency by balancing the mixing tank and circulation pipeline in the mixing chamber 200, allowing other components to be fully mixed with supercritical carbon dioxide.
[0040] Furthermore, in some embodiments of this application, the semiconductor wafer cleaning system is also provided with a discharge pipeline connected to the integrated cleaning and drying chamber; The discharge line connects to the chamber space and is equipped with a back pressure valve to discharge carbon dioxide from the integrated cleaning and drying chamber when necessary. Impurities on the wafer surface are discharged with the carbon dioxide, and the rinsing solution is soluble in... SC CO2, therefore impurities and washing liquid are present. SC CO2 flows out from the wafer surface and is then discharged through the emission pipeline.
[0041] Example 2 refer to Figure 3 , combined Figure 1 and Figure 2 This embodiment provides a semiconductor wafer cleaning method using the semiconductor wafer cleaning system provided in Embodiment 1 above, including the following steps: Cleaning solution preparation: Supercritical carbon dioxide cleaning solution is formed in the cleaning solution supply system; Chamber preparation: The wafer to be cleaned is placed into the integrated cleaning and drying chamber. The space inside the integrated cleaning and drying chamber is vacuumed. Then, the space inside the integrated cleaning and drying chamber is heated and pressurized to make the environment inside the chamber meet the supercritical conditions of supercritical carbon dioxide. The cleaning fluid supply system supplies supercritical carbon dioxide cleaning fluid to the integrated cleaning and drying chamber. The wafer is cleaned by driving it to rotate. The cleaning solution spray pipe 2 sprays supercritical carbon dioxide cleaning solution onto the wafer for cleaning. The drying heating pipe 3 maintains the temperature during the cleaning process, keeping the supercritical carbon dioxide in a supercritical state. The cleaning solution supply system supplies supercritical carbon dioxide to the integrated cleaning and drying chamber for drying the wafer. The drying heating tube 3 controls the temperature and dries the wafer surface.
[0042] The semiconductor wafer cleaning method provided in this embodiment uses the semiconductor wafer cleaning system provided in this application. This allows the cleaning and drying steps to be performed within a single chamber during the supercritical carbon dioxide cleaning process. This maintains a stable surface temperature on the wafer during cleaning, preventing significant temperature changes due to transfer, and thus ensuring the cleaning process continues. SC CO2 is stable in its supercritical state, resulting in high cleaning efficiency and minimal residue on the wafer surface. Furthermore, it allows for smaller equipment size, lower costs, and increased cleaning efficiency.
[0043] During chamber preparation, the chamber is evacuated to ensure it is air-free before heating and pressurization. Therefore, after this step, the chamber contains only... SC CO2. The supercritical carbon dioxide cleaning solution at this point: SC CO2 encapsulates cosolvents and surfactants to form a microemulsion. The supercritical carbon dioxide cleaning solution is then sprayed into the chamber and dispersed within it, eventually distributing onto the wafer surface. SCCO2 does not fall directly to the bottom of the chamber. The cleaning solution containing impurities and contaminants on the wafer surface continuously dissolves into the new solution. SC The CO2 cleaning solution is used to clean the wafer.
[0044] Furthermore, in some embodiments of this application, the step of preparing the cleaning solution includes: To balance the mixing chamber, heating and pressurization are applied to meet the supercritical state requirements of carbon dioxide; Carbon dioxide is supplied to the equilibrium mixing chamber through a carbon dioxide supply source; other components are supplied to the equilibrium mixing chamber through a supply source of other components; the other components circulate in the equilibrium mixing chamber and mix with carbon dioxide under heating and pressurization to form a supercritical carbon dioxide cleaning solution; Other components include solubilizers, surfactants, and other additives.
[0045] Furthermore, in some embodiments of this application, the supercritical carbon dioxide cleaning fluid includes a first cleaning fluid, a second cleaning fluid, and a third cleaning fluid with three different components; the first cleaning fluid, the second cleaning fluid, and the third cleaning fluid are formed by mixing carbon dioxide with different other components (or the same other components but in different proportions) in a balanced mixing chamber.
[0046] The process of cleaning a wafer includes at least the following steps: The wafer surface is cleaned with a first cleaning solution to reduce the wafer surface tension and the adsorption force on surface particles; the first cleaning solution is a mixture of supercritical carbon dioxide and surfactant. The wafer surface is cleaned with a second cleaning solution to enhance the solubility of contaminant particles on the wafer surface; the second cleaning solution is a mixture of supercritical carbon dioxide and a co-solvent. The wafer surface is cleaned with a second cleaning solution to rinse away contaminant particles; the third cleaning solution is a mixture of supercritical carbon dioxide and a cleaning agent.
[0047] The semiconductor wafer cleaning method provided in this embodiment uses three supercritical carbon dioxide cleaning solutions with different compositions. First, the first cleaning solution reduces the surface tension of the wafer and decreases the adsorption force on surface particles. Then, the second cleaning solution enhances the solubility of contaminant particles on the wafer surface. Finally, the third cleaning solution rinses and removes contaminant particles from the wafer surface, ensuring excellent cleaning results.
[0048] Furthermore, in some embodiments of this application, in the chamber preparation step, the temperature inside the chamber space of the integrated cleaning and drying chamber is heated to 40°C to 200°C, and the pressure is increased to 8 to 16 MPa, and maintained for at least 10 minutes; In the step of supplying cleaning fluid, the initial flow rate of supercritical carbon dioxide cleaning fluid is 2L / min, maintained for 10s and then adjusted to 5L / min, maintained for 10s and then adjusted to 10L / min, and the fluid is then purged into the chamber through cleaning fluid spray pipe 2 for 10min; the chamber pressure is maintained at 8~16MPa. In the wafer cleaning process, the flow rate of each cleaning solution spray pipe 2 is 1L / min~4L / min, the pipe opening is 8mm away from the wafer surface, and the wafer rotation speed is 500rpm; the cleaning time of the first cleaning solution is 60s~120s, the cleaning time of the second cleaning solution is 60s~120s, and the cleaning time of the third cleaning solution is 60s~120s; during the cleaning process, the temperature in the integrated cleaning and drying chamber is maintained at 40℃~200℃, and the pressure is maintained at 8~16MPa. In the wafer drying step, the supercritical carbon dioxide is sprayed into the chamber space by the cleaning solution spray pipe 2 at a flow rate of 1L / min to 4L / min. The temperature in the integrated cleaning and drying chamber space is maintained at 40℃ to 200℃, the pressure is maintained at 8 to 16MPa, and the drying time is 1min to 10min.
[0049] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this application.
Claims
1. A semiconductor wafer cleaning system, characterized in that, include: Cleaning fluid supply system and integrated cleaning and drying chamber; The cleaning fluid supply system is adapted to provide supercritical carbon dioxide cleaning fluid to the integrated cleaning and drying chamber; The integrated cleaning and drying chamber includes: The chamber shell surrounds a closed chamber space and is connected to the cleaning fluid supply system; A wafer support module, which is adapted to fix the wafer to be cleaned and dried in the cavity space and to drive the wafer to rotate; A plurality of cleaning fluid spray pipes are distributed on at least one side of the inner wall of the chamber housing, and are adapted to spray the supercritical carbon dioxide cleaning fluid supplied by the cleaning fluid supply system onto the wafer. A plurality of drying heating tubes are distributed on at least one side of the inner wall of the chamber shell, which are adapted to control the temperature in the chamber space to maintain the stability of the supercritical state of carbon dioxide. The main heating element is adapted to heat the ambient temperature within the chamber space to dry the wafer after cleaning.
2. The semiconductor wafer cleaning system according to claim 1, characterized in that, The drying heating tube is nested within the outer wall of the cleaning liquid spray tube; the opening of the cleaning spray tube extends beyond the opening of the drying heating tube. The cleaning fluid spray pipe and the drying heating pipe are evenly distributed on their respective surfaces, with multiple concentric rings distributed from the center outwards, and the cleaning fluid spray pipes are evenly distributed in each concentric ring; the number of the concentric rings is greater than or equal to 2; the cleaning fluid spray pipe and the drying heating pipe are also provided at the center of the surface on which the cleaning fluid spray pipe and the drying heating pipe are located.
3. The semiconductor wafer cleaning system according to claim 1, characterized in that, The wafer support module is a bracket-type chuck module, comprising: The grippers, adapted to engage and hold the wafer, are relatively distributed. A support frame includes a connecting frame and a support column. The connecting frame connects the gripper and the support column. The support column is adapted to rotate and drive the connecting frame and the gripper to rotate, thereby driving the wafer to rotate. The connecting frame is a distributed linkage structure with spaces between adjacent linkages, exposing the surface of the wafer facing the support frame.
4. The semiconductor wafer cleaning system according to claim 1, characterized in that, The cleaning fluid supply system includes a balance mixing chamber, which is adapted to mix carbon dioxide and other components and heat and pressurize them to form a supercritical carbon dioxide cleaning fluid. The other components include solubilizers, surfactants, and other additives; The cleaning fluid supply system also includes a carbon dioxide supply source, a cosolvent supply source, a surfactant supply source, and other auxiliary agent supply sources, which are connected to the equilibrium mixing chamber through supply pipelines, and each of the supply pipelines is equipped with a shut-off valve.
5. The semiconductor wafer cleaning system according to claim 4, characterized in that, The balanced mixing chamber includes a mixing tank and a circulation pipeline. The circulation pipeline is equipped with a circulation pump, and the mixing tank is suitable for heating and pressurization. The other components are adapted to circulate in the equilibrium mixing chamber through the circulation pipeline and the circulation pump, and mix with carbon dioxide in the mixing tank under heating and pressurization to form a supercritical carbon dioxide cleaning solution. The balanced mixing chamber is connected to the integrated cleaning and drying chamber and to the cleaning liquid spray pipe. The pipeline connected to the integrated cleaning and drying chamber is equipped with a throttling valve.
6. The semiconductor wafer cleaning system according to claim 1, characterized in that, The semiconductor wafer cleaning system is also equipped with a discharge pipeline connected to the integrated cleaning and drying chamber; The discharge pipeline connects to the chamber space, and the discharge pipeline is equipped with a back pressure valve to discharge carbon dioxide from the integrated cleaning and drying chamber when needed.
7. A semiconductor wafer cleaning method, characterized in that, Using the semiconductor wafer cleaning system according to any one of claims 1-6, the steps include: Cleaning solution preparation: Supercritical carbon dioxide cleaning solution is formed in the cleaning solution supply system. Chamber preparation: The wafer to be cleaned is placed into the integrated cleaning and drying chamber. The space inside the integrated cleaning and drying chamber is vacuumed. Then, the space inside the integrated cleaning and drying chamber is heated and pressurized to make the environment inside the chamber meet the supercritical conditions of supercritical carbon dioxide. A cleaning fluid supply system supplies supercritical carbon dioxide cleaning fluid to the integrated cleaning and drying chamber. The wafer is cleaned by driving it to rotate, and the cleaning solution spray pipe sprays supercritical carbon dioxide cleaning solution onto the wafer for cleaning. The drying heating tube maintains the temperature during the cleaning process, so that the supercritical carbon dioxide is kept in a supercritical state. The cleaning solution supply system supplies supercritical carbon dioxide to the integrated cleaning and drying chamber for drying the wafer. The drying heating tube controls the temperature to maintain the supercritical state of the supercritical carbon dioxide. The main heating component raises the temperature of the space inside the chamber to dry the wafer surface.
8. The semiconductor wafer cleaning method according to claim 7, characterized in that, The steps for preparing the cleaning solution include: To balance the mixing chamber, heating and pressurization are applied to meet the supercritical state requirements of carbon dioxide; Carbon dioxide is supplied to the equilibrium mixing chamber through a carbon dioxide supply source; other components are supplied to the equilibrium mixing chamber through a supply source of other components; the other components circulate in the equilibrium mixing chamber and mix with carbon dioxide under heating and pressurization to form a supercritical carbon dioxide cleaning solution; The other components include cosolvents, surfactants, and other additives.
9. The semiconductor wafer cleaning method according to claim 8, characterized in that, The supercritical carbon dioxide cleaning solution comprises three different cleaning solutions: a first cleaning solution, a second cleaning solution, and a third cleaning solution. The wafer cleaning process includes at least the following steps: The wafer surface is cleaned with a first cleaning solution to reduce the wafer surface tension and reduce the adsorption force on surface particles; the first cleaning solution is a mixture of supercritical carbon dioxide and surfactant. The wafer surface is cleaned with a second cleaning solution to enhance the solubility of contaminant particles on the wafer surface; the second cleaning solution is a mixture of supercritical carbon dioxide and a co-solvent. The wafer surface is cleaned with a second cleaning solution to rinse away contaminant particles on the wafer surface; the third cleaning solution is a mixture of supercritical carbon dioxide and a cleaning agent.
10. The semiconductor wafer cleaning method according to claim 9, characterized in that, In the chamber preparation step, the temperature inside the chamber space of the integrated cleaning and drying chamber is heated to 40℃~200℃ and the pressure is increased to 8~16MPa, and maintained for at least 10 minutes. In the step of supplying the cleaning fluid, the initial flow rate of the supercritical carbon dioxide cleaning fluid is 2 L / min, which is maintained for 10 s and then adjusted to 5 L / min, maintained for 10 s and then adjusted to 10 L / min. The fluid is then sprayed into the chamber through the cleaning fluid spray pipe for 10 min. The chamber pressure is maintained at 8~16 MPa. In the wafer cleaning step, the flow rate of each cleaning solution spray pipe is 1L / min to 4L / min, the pipe opening is 8mm away from the wafer surface, and the wafer rotation speed is 500rpm; the cleaning time of the first cleaning solution is 60s to 120s, the cleaning time of the second cleaning solution is 60s to 120s, and the cleaning time of the third cleaning solution is 60s to 120s; during the cleaning process, the temperature in the integrated cleaning and drying chamber is maintained at 40℃ to 200℃, and the pressure is maintained at 8 to 16MPa; In the wafer drying step, the flow rate of supercritical carbon dioxide sprayed into the chamber space by the cleaning liquid spray pipe is 1L / min to 4L / min, the temperature in the integrated cleaning and drying chamber space is maintained at 40℃ to 200℃, the pressure is maintained at 8 to 16MPa, and the drying time is 1min to 10min.