Vacuum qdr slot and method of using the same

Abstract

The application discloses a vacuum QDR tank and a use method thereof, relates to the technical field of semiconductor manufacturing equipment, and aims to solve the problems of low cleaning efficiency, poor wafer adaptability, and easy water mark or oxidation layer residue after cleaning of the existing QDR tank. The vacuum QDR tank comprises a tank body assembly, a vacuum assembly, a fluid control assembly, a positioning assembly and a sealing opening and closing assembly; the tank body assembly comprises an outer tank body and an inner tank body, the inner tank body is provided with an overflow port, and an overflow cavity is formed between the outer tank body and the inner tank body; the vacuum assembly is connected with a vacuum pump through a vacuum suction pipe to form a negative pressure environment in the outer tank body; the fluid control assembly comprises a spraying piece, a quick exhaust pipe and a flow uniformizing plate; the positioning assembly is adapted to fix 4-inch and 6-inch wafer boxes; and the sealing opening and closing assembly realizes sealing of the tank body. The scheme can simultaneously adapt to wafers of multiple specifications, improves cleaning efficiency and cleanliness, avoids wafer oxidation and water mark residue, is stable in operation, convenient to maintain, and is suitable for large-scale application in the semiconductor wet cleaning link.

Description

Technical Field

[0001] This invention relates to the field of wafer cleaning, and more specifically, to a vacuum QDR tank and its usage method. Background Technology

[0002] After photolithography and etching processes, semiconductor wafers retain contaminants such as photoresist, chemical reagents, metal ions, and micron-sized particles on their surfaces. These contaminants can cause short circuits, performance degradation, or reduced yield in chip circuits, thus requiring thorough removal through wet cleaning. The QDR (Quick Dump Rinse) tank, as the core module of wet cleaning, works by rapidly injecting deionized water to rinse the wafer and then quickly draining the waste liquid, thereby removing contaminants. However, traditional QDR tanks have many technical limitations, making it difficult to meet the high cleanliness and efficiency requirements of advanced processes.

[0003] In existing technologies, QDR tanks mostly adopt an atmospheric pressure structure, resulting in slow deionized water injection speed, low wafer immersion efficiency, and turbulent flow field during spray rinsing, easily creating cleaning dead zones and leading to incomplete removal of chemical residues and particulate contaminants from the wafer surface. Furthermore, traditional QDR tanks have a single wafer positioning structure, typically only compatible with a single wafer cassette size. When cleaning wafers of different sizes is required, the positioning components or equipment must be changed, making operations cumbersome and significantly reducing production efficiency. In addition, traditional QDR tanks rely on gravity for drainage, resulting in slow drainage speeds. During drainage, wafers are easily exposed to air, and contact with oxygen molecules or water vapor can generate a natural oxide layer, affecting the stability of subsequent processes. Incomplete drainage can also leave watermarks on the wafer surface, causing secondary contamination.

[0004] In addition, the existing QDR tanks have poor sealing performance, making them prone to air and water leaks during the cleaning process. This not only affects the cleaning effect but may also lead to equipment failure. Furthermore, the monitoring and control of parameters such as liquid level and pressure are mostly independent operations, making it impossible to achieve coordinated control and ensuring the stability and consistency of the cleaning process. This results in differences in the cleaning quality of different batches of wafers. Summary of the Invention

[0005] The purpose of this invention is to provide a vacuum QDR tank and its usage method, which can overcome at least one of the defects of the existing QDR tank, such as low cleaning efficiency, easy residue of water marks or oxide layer after cleaning, and poor operational stability.

[0006] The technical solution of this invention is implemented as follows: A vacuum QDR tank is used in the semiconductor wet cleaning process, including a tank body assembly, a vacuum assembly, a fluid control assembly, a positioning assembly, and a sealing and opening assembly; The tank assembly includes an outer tank and an inner tank disposed in the inner cavity of the outer tank. The inner tank is used for wafer cleaning. The inner tank has an overflow port. The cavity between the outer tank and the inner tank is formed as an overflow cavity. The vacuum assembly includes a vacuum suction tube disposed in the outer tank, which is used to connect an external pumping device to create a negative pressure environment inside the outer tank. The fluid control assembly includes a spray element located in the inner tank, a slow discharge pipe and a fast discharge pipe located at the bottom of the outer tank, a fast discharge valve being provided on the fast discharge pipe, and a flow equalization plate being provided in the inner tank, with wafer cassettes of various specifications being provided on the flow equalization plate. The positioning component is disposed on the flow equalization plate and is used for positioning and fixing the wafer cassette; The sealing and opening assembly includes an automatic cover that mates with the top opening of the outer tank and a drive unit that drives the automatic cover to open and close. After the automatic cover is closed, it forms a sealed cavity with the tank assembly.

[0007] Furthermore, a 4-inch wafer cassette and a 6-inch wafer cassette are arranged side by side on the flow equalization plate; the positioning assembly includes a wafer cassette positioning block and a positioning post disposed on the flow equalization plate. The wafer cassette positioning block and the positioning post cooperate to simultaneously adapt and fix the 4-inch wafer cassette and the 6-inch wafer cassette; multiple positioning posts are disposed between the 4-inch wafer cassette and the 6-inch wafer cassette to abut and fix the inner side of the 6-inch wafer cassette and the outer side of the 4-inch wafer cassette for positioning, and positioning blocks are respectively disposed on the opposite sides of the 4-inch wafer cassette and the 6-inch wafer cassette for fixing them.

[0008] Furthermore, the spraying component is a spray pipe, which is equipped with nozzles and connectors. The spray pipe is installed on the inner wall of the inner tank using fixing clamps. The spray pipe is used for directional high-pressure spraying and full coverage of the wafer. Preferably, there are at least two spray pipes, symmetrically arranged in the inner tank to ensure no dead corners in the spraying and improve cleaning uniformity. The nozzles are atomizing nozzles, which can atomize deionized water and spray it onto the wafer surface, avoiding direct impact of high-pressure water flow that could damage the wafer, while also improving the removal effect of contaminants.

[0009] Furthermore, the driving component is a cylinder, with its piston end connected to the automatic cover and its fixed block end fixedly connected to the outer tank. The automatic cover is also equipped with at least two liquid level detection devices, used to detect the liquid levels in the inner and outer tanks respectively. The cylinder-driven method offers rapid response and stable operation, enabling quick opening and closing of the automatic cover and improving the automation level of the equipment. Simultaneously, the cylinder structure is simple and easy to maintain, making it suitable for the high-cleanliness environment requirements of semiconductor manufacturing.

[0010] Furthermore, the liquid level detection device is a float level gauge, with two float level gauges, namely a first float level gauge and a second float level gauge, used to detect the liquid level in the inner tank and the liquid level in the outer tank, respectively. The signal outputs of the first float level gauge and the second float level gauge are respectively connected to the control system, which is used for the linkage control of the float level gauge with the quick-release valve and vacuum assembly. The float level gauge works based on the principle of buoyancy, realizing liquid level detection by the rise and fall of the float with the liquid level. It has high detection accuracy and good stability, suitable for the liquid level monitoring needs of semiconductor cleaning equipment, and can provide real-time feedback on the liquid level status of the inner and outer tanks, providing accurate signal support for linkage control.

[0011] Furthermore, the outer tank is also equipped with a pressure detection element, which is a pressure sensor used to detect the pressure parameters inside the tank. The outer tank is also equipped with an air inlet for injecting nitrogen or inert gas into the tank. The pressure sensor can monitor the negative pressure value in the sealed cavity in real time, ensuring that the negative pressure environment is stable within a preset range, and avoiding excessively high or low negative pressure from affecting the cleaning effect. The nitrogen or inert gas injected through the air inlet can reduce the oxygen content in the deionized water, preventing the formation of an oxide layer on the wafer surface. At the same time, it can achieve gas bubbling, increase the scouring force of the deionized water, improve the cleaning effect, and also play a self-cleaning role for the tank itself.

[0012] Furthermore, the inner tank, outer tank, and automatic cover are all made of NPP material. The flow equalization plate has multiple uniformly distributed flow equalization holes to transform turbulent fluid into a stable and uniform flow field. NPP material (modified polypropylene) has excellent corrosion resistance, high-temperature resistance, and no precipitation characteristics, allowing for long-term stable operation in strong acid and alkali cleaning environments such as HF and H2SO4, preventing material swelling or the introduction of new contaminants by precipitates, thus ensuring the cleanliness of the wafer cleaning. The flow equalization holes in the flow equalization plate can rectify the turbulent deionized water sprayed and injected into a stable and uniform flow field, avoiding uneven cleaning caused by excessively fast or slow local flow rates. Simultaneously, it allows for continuous renewal of deionized water at wafer seams and corners, improving contaminant removal efficiency.

[0013] Furthermore, the extraction device is a vacuum pump. After being connected to a vacuum suction pipe, the vacuum pump creates a negative pressure within the sealed cavity. This negative pressure environment enables rapid intake of deionized water, micro-circulation of the liquid within the tank, and rapid discharge of waste liquid. After cleaning, the waste liquid is rapidly emptied via the quick-drain valve using the pressure difference between the negative pressure within the tank and atmospheric pressure. The vacuum pump can be selected according to the required vacuum level, preferably in the medium vacuum range (10³Pa~10⁻⁶Pa). -The vacuum pump (¹Pa) can achieve rapid intake of deionized water and rapid discharge of waste liquid, while avoiding damage to the wafer caused by excessive negative pressure. At the same time, the vacuum pump can handle liquid-containing gases, is corrosion-resistant, and is suitable for the working environment of semiconductor cleaning equipment. Its pumping speed can be flexibly adjusted according to the equipment specifications to ensure that the negative pressure environment is quickly established and maintained stably.

[0014] Furthermore, the number of vacuum suction tubes is at least one, preferably two, and they are symmetrically arranged on both sides of the outer tank to ensure uniform negative pressure distribution inside the outer tank and avoid problems such as poor sealing or uneven cleaning caused by local negative pressure differences.

[0015] Furthermore, the overflow port of the inner tank is a V-shaped or U-shaped overflow port located at the upper end of the inner tank. The liquid overflowing from the inner tank can be discharged through the overflow chamber from the slow drain pipe and / or fast drain pipe. The V-shaped or U-shaped overflow port can achieve constant control of the liquid level in the inner tank, ensuring that the wafer is always immersed during the cleaning process. At the same time, the overflow liquid can carry surface-floating contaminants into the overflow chamber, achieving contaminant separation and avoiding secondary pollution. The overflow chamber can buffer the flow rate of the overflow liquid, reduce the impact on the tank, and facilitate the centralized collection and discharge of waste liquid.

[0016] The present invention also provides a method of using the above-mentioned vacuum QDR tank, comprising the following steps: S1. Place the wafer cassettes into the inner groove of the vacuum QDR tank, and achieve precise positioning of the wafer cassettes through positioning components; specifically, place 4-inch wafer cassettes and 6-inch wafer cassettes side by side on the flow equalization plate, and simultaneously fix the two wafer cassettes through the cooperation of the wafer cassette positioning blocks and positioning posts. The positioning posts abut against the inner side of the 6-inch wafer cassette and the outer side of the 4-inch wafer cassette, and the positioning blocks fix the opposite sides of the two wafer cassettes respectively, ensuring that the wafer cassettes do not shift during the cleaning process and ensuring cleaning uniformity.

[0017] S2. Activate the sealing and opening / closing assembly. The drive unit drives the automatic cover to close, completing the sealing action and forming a sealed cavity between the inner and outer tanks. Specifically, the cylinder drives the piston end to extend and retract, causing the automatic cover to move downward and fit tightly against the top opening of the outer tank, forming a sealed cavity. This ensures the stable establishment of the subsequent negative pressure environment and avoids air leakage that could affect the negative pressure effect.

[0018] S3. Start the vacuum assembly to extract gas from the outer tank through the vacuum suction tube on the outer tank, establishing and maintaining a negative pressure environment inside the outer tank; specifically, start the vacuum pump to extract air from the outer tank through the vacuum suction tube, the pressure sensor detects the pressure parameters inside the tank in real time and feeds the signal back to the control system, the control system adjusts the pumping speed of the vacuum pump to stabilize the negative pressure inside the outer tank within a preset range (preferably medium vacuum level), and at the same time inject an appropriate amount of nitrogen or inert gas through the air inlet to reduce the oxygen content inside the tank and avoid wafer oxidation.

[0019] S4. Under negative pressure, deionized water is injected into the inner tank. The negative pressure difference accelerates the immersion of the wafers on the wafer cassette by the DIW (deionized water), and the spray system is activated simultaneously for high-pressure directional spraying to achieve full-area coverage rinsing. Specifically, under negative pressure, deionized water is rapidly drawn into the inner tank, increasing the immersion speed by more than 30% compared to normal pressure. At the same time, the symmetrically arranged spray pipes are activated to spray high-pressure atomized deionized water onto the wafer surface through nozzles, achieving full-area coverage spraying of the wafer surface. This removes chemical residues and particulate contaminants from the wafer surface. The atomized spraying avoids wafer damage caused by direct water flow impact and improves contaminant removal efficiency.

[0020] S5. Under negative pressure maintenance, a constant liquid level is continuously convected and replaced through the overflow port of the inner tank and the overflow cavity. At the same time, the flow equalizer plate rectifyes the turbulent inflow into a stable and uniform flow field to remove chemical residues and particulate contaminants from the wafer surface. Specifically, deionized water is continuously injected into the inner tank, and excess liquid flows into the overflow cavity through the overflow port, forming a continuous convection and replacement, which carries the contaminants peeled off from the wafer surface into the overflow cavity, achieving contaminant separation. At the same time, the flow equalizer plate rectifyes the turbulent deionized water flow into a stable and uniform flow field, ensuring that the cleaning intensity of all parts of the wafer is consistent, avoiding cleaning dead zones, and further improving the cleaning cleanliness. This can improve the efficiency of removing particulate matter from the wafer surface and reduce the concentration of metal ions.

[0021] S6. After cleaning, immediately open the quick-drain valve on the bottom quick-drain pipe. Driven by the pressure difference between the negative pressure inside the outer tank and the external atmospheric pressure, the liquid in the tank is quickly and completely drained, achieving a dry state without watermarks or oxide layers on the wafer surface. Specifically, after cleaning, the control system receives a signal and opens the quick-drain valve. Utilizing the pressure difference between the negative pressure inside the tank and the external atmospheric pressure, the waste liquid in the inner tank and overflow chamber is quickly discharged through the quick-drain pipe. The drainage time is shortened compared to traditional atmospheric pressure QDR tanks, significantly reducing the time the wafer is exposed to air and preventing oxide layer formation. At the same time, the negative pressure environment allows the moisture on the wafer surface to evaporate quickly, achieving watermark-free drying, avoiding secondary contamination, and ensuring the stability of subsequent wafer processing.

[0022] Compared with the prior art, the beneficial effects of the present invention are: 1. Adaptable to multiple wafer sizes, improving production efficiency: The positioning component can be used to position and install various types of wafer cassettes on the flow equalization plate. Different wafer sizes can be cleaned without changing the positioning component or equipment. The operation is convenient, greatly improving production efficiency, adapting to the multi-specification production needs of semiconductor manufacturing, and reducing equipment investment costs.

[0023] 2. High cleaning efficiency and superior cleanliness: A negative pressure environment is created inside the outer tank using vacuum components, enabling rapid intake of deionized water and increasing wafer immersion speed compared to atmospheric pressure. Simultaneously, the pressure difference between the negative pressure and atmospheric pressure allows for rapid waste liquid drainage, shortening drainage time and significantly improving cleaning cycle efficiency. Furthermore, the spray system provides full-area high-pressure atomization spray, and combined with the flow field rectification effect of the flow equalization plate, it avoids cleaning dead zones, improving the efficiency of removing particles from the wafer surface and effectively removing chemical residues and particulate contaminants, thus enhancing cleaning cleanliness.

[0024] 3. Avoid watermarks on wafers: After cleaning, the waste liquid is quickly emptied by using the pressure difference between negative pressure and atmospheric pressure, reducing the time the wafer is exposed to air. At the same time, the negative pressure environment promotes the rapid evaporation of moisture on the wafer surface, achieving a dry state without watermarks or oxide layers, ensuring the stability of subsequent wafer processes and improving chip yield. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the overall structure of the vacuum QDR groove of the present invention; Figure 2 This is a top view of the tank assembly and positioning assembly of the present invention; Figure 3 This is a schematic diagram of the flow uniform plate of the present invention; Figure 4 This is a flowchart illustrating the method of using the present invention; Explanation of reference numerals in the attached figures: 101-Inner tank; 102-Outer tank; 103-Automatic cover; 104-Cylinder; 105-Slow discharge pipe; 106-Fast discharge pipe; 107-First float level gauge; 108-Second float level gauge; 109-Vacuum suction tube; 110-6-inch wafer cassette; 112-4-inch wafer cassette; 113-spray pipe; 114-pressure sensor; 115-cassette positioning block; 117-flow equalizer; 118-positioning post. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0028] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0029] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0030] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are only for the convenience of describing this invention 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, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0031] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0032] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" 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 mechanical connection or an electrical 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 invention based on the specific circumstances.

[0033] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0034] Example 1 like Figures 1-4 As shown, this embodiment provides a vacuum QDR tank for use in semiconductor wet cleaning processes. It includes a tank assembly, a vacuum assembly, a fluid control assembly, a positioning assembly, and a sealing and opening assembly. The components work together to achieve efficient and high-cleanliness cleaning of wafers of various sizes.

[0035] The tank assembly is the basic structure of the equipment, including an outer tank 102 and an inner tank 101. The inner tank 101 is fixedly installed in the inner cavity of the outer tank 102. The inner tank 101 is used to place wafer cassettes and perform wafer cleaning. A V-shaped overflow port (or a U-shaped overflow port) is provided at the upper end of the inner tank 101. The cavity between the outer tank 102 and the inner tank 101 forms an overflow cavity. The cleaning fluid overflowing from the inner tank 101 is collected in the overflow cavity and discharged through the slow drain pipe 105 and / or fast drain pipe 106 at the bottom of the outer tank 102 to achieve centralized treatment of waste liquid. Both the inner tank 101 and the outer tank 102 are made of NPP material. NPP material has excellent corrosion resistance, high temperature resistance and non-precipitation characteristics. It can operate stably in strong acid and strong alkali cleaning environments such as HF and HSO for a long time, avoiding material swelling or the introduction of new contaminants by precipitates, and ensuring the cleanliness of wafer cleaning. At the same time, NPP material is easy to process, and tanks of different sizes can be made according to actual needs to meet the cleaning needs of wafers of different specifications.

[0036] The vacuum assembly, used to create a negative pressure environment inside the outer tank 102, includes vacuum suction tubes 109 and a vacuum pump (air extraction device). Two vacuum suction tubes 109 can be arranged symmetrically on both sides of the outer tank 102. One end of each vacuum suction tube 109 communicates with the inner cavity of the outer tank 102, and the other end is connected to the vacuum pump. After the vacuum pump is started, air is extracted from the outer tank 102 through the vacuum suction tubes 109, creating a medium vacuum environment (pressure range 10³ Pa to 10⁻⁶ Pa) inside the outer tank 102. -The negative pressure environment (¹Pa) enables rapid intake of deionized water, micro-circulation of liquid within the tank, and rapid discharge of waste liquid. Simultaneously, a pressure detection device, such as a pressure sensor 114, is installed on the outer tank 102. The sensing end of the pressure sensor 114 extends into the inner cavity of the outer tank 102 to detect the pressure parameters within the tank in real time and feed the signal back to the control system. The control system adjusts the pumping speed of the vacuum pump based on the pressure signal to ensure the negative pressure environment remains stable within a preset range. Furthermore, the outer tank 102 is equipped with an air inlet for injecting nitrogen or inert gas into the tank, reducing the oxygen content in the deionized water, preventing the formation of an oxide layer on the wafer surface, and simultaneously enabling gas bubbling, increasing the flushing force of the deionized water, improving the cleaning effect, and also providing a self-cleaning function for the tank itself.

[0037] The fluid control assembly is used to achieve spraying, uniform flow, and rapid discharge of cleaning fluid, including spray pipe 113 (spray component), slow discharge pipe 105, fast discharge pipe 106, fast discharge valve, and flow equalization plate 117. There are two spray pipes 113, symmetrically arranged on the inner wall of the inner tank 101. The spray pipes 113 are fixedly installed by fixing pipe clamps. Multiple atomizing nozzles and connectors are evenly distributed on the spray pipes 113. The connectors are used to connect to the external deionized water pipeline. The atomizing nozzles can atomize the deionized water and spray it onto the wafer surface to achieve directional high-pressure spraying and full coverage, avoiding direct impact of high-pressure water flow that could damage the wafer, while improving the effect of contaminant removal. The flow equalization plate 117 is horizontally installed at the bottom of the inner tank 101. The flow equalization plate 117 has multiple flow equalization holes (the hole diameter can be designed to be 10mm) evenly distributed on it. These holes are used to rectify the turbulent deionized water sprayed and injected into a stable and uniform flow field, avoiding uneven cleaning caused by excessively fast or slow local flow rates. At the same time, it can continuously refresh the deionized water in the wafer seams and corners, improving the pollutant removal effect. The fast discharge pipe 106 and the slow discharge pipe 105 are respectively installed at the bottom of the outer tank 102. An electric valve can be installed on the slow discharge pipe 105 to control its opening and closing. The slow discharge pipe 105 is used when the overflow flow in the outer tank 102 is small, while the fast discharge pipe 106 is used when the overflow flow in the outer tank 102 is large to achieve rapid discharge. One end of the fast discharge pipe 106 is connected to the overflow chamber, and the other end extends to the outside of the equipment. The fast discharge pipe 106 is equipped with a fast discharge valve. The fast discharge valve can be a fast-opening type valve, which has the characteristic that the flow rate is close to the maximum value when the valve core is slightly displaced, meeting the requirements of rapid opening and closing, and can realize the rapid emptying of waste liquid.

[0038] A positioning assembly is mounted on the flow equalization plate 117 to achieve positioning and fixing of multi-specification wafer cassettes, including cassette positioning blocks 115 and positioning posts 118. A 4-inch wafer cassette 112 and a 6-inch wafer cassette 110 are arranged side-by-side on the flow equalization plate 117. The cassette positioning blocks 115 and positioning posts 118 cooperate to simultaneously fix the two wafer cassettes: multiple positioning posts 118 are arranged between the 4-inch wafer cassette 112 and the 6-inch wafer cassette 110, and the positioning posts 118 are vertically fixed on the flow equalization plate 117 to abut and fix the inner side of the 6-inch wafer cassette 110 and the outer side of the 4-inch wafer cassette 112, achieving radial positioning; one wafer cassette positioning block 115 is arranged on the left side of the 4-inch wafer cassette 112 and the right side of the 6-inch wafer cassette 110. The wafer cassette positioning block 115 can adopt an L-shaped structure to abut the end of the wafer cassette, achieving axial positioning, ensuring that the wafer cassette does not shift during the cleaning process, and ensuring cleaning uniformity. The positioning component has a simple structural design and can be adapted to 4-inch and 6-inch wafer cassettes 110 without replacement, making it easy to operate and improving production efficiency.

[0039] The sealing and opening assembly is used to seal the tank body and includes an automatic cover 103 and a cylinder 104 (driving component). The automatic cover 103 is made of NPP material and matches the top opening of the outer tank body 102. The bottom of the automatic cover 103 is equipped with a sealing ring to improve sealing performance and prevent air and water leakage. The fixed block end of the cylinder 104 is fixedly connected to the side wall of the outer tank body 102, and the piston end of the cylinder 104 is fixedly connected to the top of the automatic cover 103. The cylinder 104 drives the piston end to extend and retract, causing the automatic cover 103 to move up and down, realizing the opening and closing of the automatic cover 103. After the automatic cover 103 is closed, it forms a sealed cavity with the tank body assembly to ensure the stable establishment of a negative pressure environment. In addition, two float level gauges (level detection devices) are installed on the automatic cover 103, namely a first float level gauge 107 and a second float level gauge 108. The detection end of the first float level gauge 107 extends into the inner cavity of the inner tank 101 to detect the liquid level in the inner tank 101; the detection end of the second float level gauge 108 extends into the overflow cavity to detect the liquid level in the outer tank 102. The signal output terminals of both float level gauges are connected to the control system, which is used to realize the linkage control of the float level gauges, the quick-release valve, and the vacuum assembly: when the liquid level in the inner tank 101 reaches the preset upper limit, the first float level gauge 107 sends a signal to the control system, and the control system controls the deionized water injection pipeline to close while maintaining the overflow state; when the liquid level in the overflow cavity reaches the preset upper limit, the second float level gauge 108 sends a signal to the control system, and the control system opens the quick-release valve to discharge some waste liquid and ensure the liquid level is stable.

[0040] The control system can use a PLC controller, which integrates functions such as signal acquisition, parameter adjustment, and logic control. It can receive the detection signals from the float level gauge and pressure sensor 114 in real time, and simultaneously control the operating status of the vacuum pump, cylinder 104, quick exhaust valve, and spray pipe 113, so as to realize the automated and intelligent control of the cleaning process and ensure the stability and consistency of the cleaning process.

[0041] Example 2 This embodiment also provides a method for using the above-mentioned vacuum QDR tank, including the following steps: S1. Wafer cassette positioning: Wafer cassettes containing 4-inch wafers and cassettes containing 6-inch wafers are placed side by side on the flow equalization plate 117 of the inner tank 101. Precise positioning is achieved through the cooperation of the wafer cassette positioning block 115 and the positioning post 118: the positioning post 118 abuts against the inner side of the 6-inch wafer cassette and the outer side of the 4-inch wafer cassette 112 to achieve radial positioning; the wafer cassette positioning block 115 abuts against the opposite ends of the two wafer cassettes to achieve axial positioning, ensuring that the wafer cassettes do not shift during the cleaning process.

[0042] S2. Formation of a sealed cavity: The sealing opening and closing assembly is activated, and the control system controls the piston end of the cylinder 104 to extend and retract downward, driving the automatic cover 103 to move downward and fit tightly against the top opening of the outer tank 102. The sealing is achieved through the sealing ring, so that the inner tank 101 and the outer tank 102 form a sealed cavity, ensuring the stable establishment of the subsequent negative pressure environment.

[0043] S3. Establishing a negative pressure environment: The vacuum assembly is activated, and the control system starts the vacuum pump. The vacuum pump draws air from the outer tank 102 through the vacuum suction tube 109. The pressure sensor 114 detects the pressure parameters inside the tank in real time and feeds the signal back to the control system. The control system adjusts the pumping speed of the vacuum pump to stabilize the negative pressure inside the outer tank 102 at 10³Pa~10. - The vacuum range is ¹Pa; at the same time, nitrogen is slowly injected into the tank through the air inlet, with the injection flow rate controlled at 5-10L / min, to reduce the oxygen content in the tank and avoid the formation of an oxide layer on the wafer surface.

[0044] S4. Negative Pressure Spray Cleaning: Under negative pressure, the control system controls the opening of the external deionized water pipeline. Deionized water enters the spray pipe 113 through the connector and is quickly drawn into the inner tank 101 under negative pressure, accelerating the immersion of the two wafer cassettes and wafers. At the same time, the atomizing nozzles of the spray pipe 113 are opened to spray high-pressure atomized deionized water onto the wafer surface. The spray pressure is controlled at 0.3-0.5MPa. The two symmetrically arranged spray pipes 113 achieve full coverage spraying of the wafer surface, removing chemical residues and particulate contaminants from the wafer surface.

[0045] S5. Convection Displacement Cleaning: Under negative pressure, deionized water is continuously injected into the inner tank 101. Excess liquid flows into the overflow chamber through the V-shaped overflow port, forming a constant liquid level and continuous convection displacement, which carries the contaminants peeled off from the wafer surface into the overflow chamber, achieving the separation of contaminants. At the same time, the flow equalization plate 117 straightens the turbulent deionized water flow into a stable and uniform flow field through the flow equalization hole, ensuring that the cleaning intensity of each part of the wafer is consistent, avoiding cleaning dead corners, and further improving the cleaning cleanliness. The duration of this step is controlled within 3-5 minutes.

[0046] S6. Negative Pressure Rapid Drainage: After cleaning, the control system immediately opens the rapid drain valve on the rapid drain pipe 106. Utilizing the pressure difference between the negative pressure inside the outer tank 102 and the external atmospheric pressure, the waste liquid in the inner tank 101 and the overflow chamber is driven to be quickly discharged through the rapid drain pipe 106. The drainage time is controlled within 10-15 seconds, significantly reducing the time the wafer is exposed to air. At the same time, the negative pressure environment promotes the rapid evaporation of moisture on the wafer surface, achieving a dry state without watermarks or oxide layers, thus completing the wafer cleaning.

[0047] After cleaning is completed, the control system stops the vacuum pump, and cylinder 104 drives the automatic cover 103 to open, removing the cleaned wafer cassette, which can then proceed with subsequent processes.

[0048] The vacuum QDR tank and its usage method in this embodiment achieve rapid intake of deionized water and rapid discharge of waste liquid through vacuum assistance. It is suitable for cleaning 4-inch and 6-inch wafers of various specifications, with high cleaning efficiency and excellent cleanliness. It can effectively avoid wafer oxidation and water mark residue, and has stable operation and a high degree of automation. It is suitable for large-scale application in semiconductor wet cleaning process, and can effectively improve chip yield and reduce production costs.

[0049] The beneficial effects of the technical solution of the present invention are: 1. Adaptable to multiple wafer sizes, improving production efficiency: By cooperating with the positioning block 115 and the positioning post 118 of the positioning component, 4-inch and 6-inch wafer cassettes 110 can be fixed at the same time. Different wafer sizes can be cleaned without changing the positioning component or equipment. The operation is convenient, greatly improving production efficiency, adapting to the multi-specification production needs of semiconductor manufacturing, and reducing equipment investment costs.

[0050] 2. High cleaning efficiency and superior cleanliness: A negative pressure environment is created inside the outer tank 102 through the vacuum component, enabling rapid intake of deionized water. Compared to an atmospheric pressure environment, the wafer immersion speed is increased. Simultaneously, the pressure difference between the negative pressure and atmospheric pressure allows for rapid drainage of waste liquid, shortening drainage time and significantly improving cleaning cycle efficiency. Furthermore, symmetrically arranged spray pipes 113 achieve full-area high-pressure atomization spraying, and combined with the flow field rectification effect of the flow equalization plate 117, cleaning dead zones are avoided, improving the efficiency of removing particles from the wafer surface and effectively removing chemical residues and particulate contaminants, thus enhancing cleaning cleanliness.

[0051] 3. Avoid wafer oxidation and watermark residue: During the cleaning process, nitrogen or inert gas is injected through the air inlet to reduce the oxygen content in the tank and prevent the formation of an oxide layer on the wafer surface. After cleaning, the waste liquid is quickly emptied by using the pressure difference between negative pressure and atmospheric pressure to reduce the time the wafer is exposed to air. At the same time, the negative pressure environment promotes the rapid evaporation of moisture on the wafer surface, achieving a dry state without watermarks or oxide layers, ensuring the stability of subsequent wafer processes and improving chip yield.

[0052] 4. Stable operation and high degree of automation: Through the linkage control of the float level gauge, pressure sensor 114 and control system, the liquid level and pressure parameters in the tank can be monitored in real time, and the operating status of the vacuum pump and quick exhaust valve can be automatically adjusted to ensure the stability and consistency of the cleaning process, reduce human intervention and improve the automation level of the equipment; at the same time, the automatic cover 103 driven by cylinder 104 has good sealing performance, avoiding air and water leakage, ensuring a stable negative pressure environment and extending the service life of the equipment.

[0053] 5. Strong corrosion resistance and no secondary pollution: The inner tank 101, outer tank 102, and automatic cover 103 are all made of NPP material, which has excellent corrosion resistance and no precipitation characteristics. It can operate stably in strong acid and strong alkali cleaning environments for a long time, avoiding material swelling or the introduction of new contaminants by precipitates; the overflow chamber is designed to separate contaminants from cleaning fluid, avoid secondary pollution, and further ensure the cleanliness of wafer cleaning.

[0054] 6. Reasonable structure and convenient maintenance: The equipment has a modular design for each component. The spray pipe 113 is installed by fixing pipe clamps. The positioning components, quick exhaust valves and other vulnerable parts can be quickly disassembled and replaced, making maintenance convenient. At the same time, the core components such as vacuum pump and cylinder 104 have mature structures, stable operation and low failure rate, which reduces equipment maintenance costs and is suitable for large-scale mass production applications.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A vacuum QDR bath, used in the semiconductor wet cleaning process, characterized in that, This includes tank components, vacuum components, fluid control components, positioning components, and sealing and opening / closing components; The tank assembly includes an outer tank (102) and an inner tank (101) disposed in the inner cavity of the outer tank (102). The inner tank (101) is used for wafer cleaning. The inner tank (101) has an overflow port. The cavity between the outer tank (102) and the inner tank (101) is formed as an overflow cavity. The vacuum assembly includes a vacuum suction tube (109) disposed in the outer tank (102), the vacuum suction tube (109) being used to connect an external pumping device to create a negative pressure environment inside the outer tank (102); The fluid control assembly includes a spray element disposed in the inner tank (101), a slow discharge pipe (105) and a fast discharge pipe (106) disposed at the bottom of the outer tank (102), the fast discharge pipe (106) is equipped with a fast discharge valve, and a flow equalization plate (117) is also disposed in the inner tank (101), and various sizes of wafer cassettes are disposed on the flow equalization plate (117); The positioning component is disposed on the flow equalization plate (117) and is used for positioning and fixing the wafer cassette; The sealing and opening assembly includes an automatic cover (103) that mates with the top opening of the outer tank (102) and a drive unit that drives the automatic cover (103) to open and close. After the automatic cover (103) is closed, it forms a sealed cavity with the tank assembly.

2. The vacuum QDR tank according to claim 1, characterized in that, A 4-inch wafer cassette (112) and a 6-inch wafer cassette (110) are arranged side by side on the flow equalization plate (117). The positioning component includes a wafer cassette positioning block (115) and a positioning post (118) disposed on the flow equalization plate (117). The wafer cassette positioning block (115) and the positioning post (118) cooperate to simultaneously adapt and fix a 4-inch wafer cassette (112) and a 6-inch wafer cassette (110). Multiple positioning posts (118) are provided between the 4-inch wafer cassette (112) and the 6-inch wafer cassette (110) for positioning by abutting and fixing the inner side of the 6-inch wafer cassette (110) and the outer side of the 4-inch wafer cassette (112). Positioning blocks are provided on the opposite sides of the 4-inch wafer cassette (112) and the 6-inch wafer cassette (110) for fixing them.

3. The vacuum QDR tank according to claim 1, characterized in that, The spraying component is a spray pipe (113), which is equipped with nozzles and connectors. The spray pipe (113) is installed on the inner wall of the inner tank (101) by fixing pipe clamps. The spray pipe (113) is used for directional high-pressure spraying and full coverage of the wafer.

4. The vacuum QDR tank according to claim 1, characterized in that, The driving component is a cylinder (104). The piston end of the cylinder (104) is connected to the automatic cover (103), and the fixed block end of the cylinder (104) is fixedly connected to the outer tank (102). At least two liquid level detection components are also installed on the automatic cover (103), which are used to detect the liquid level of the inner tank (101) and the outer tank (102) respectively.

5. The vacuum QDR tank according to claim 1, characterized in that, The liquid level detection device is a float level gauge, and the two float level gauges are a first float level gauge (107) and a second float level gauge (108), which are used to detect the liquid level in the inner tank (101) and the liquid level in the outer tank (102), respectively. The signal outputs of the first float level gauge (107) and the second float level gauge (108) are respectively connected to the control system, which is used for the linkage control of the float level gauge, the quick exhaust valve and the vacuum assembly.

6. The vacuum QDR tank according to claim 1, characterized in that, The outer tank (102) is also provided with a pressure detection element, which is a pressure sensor (114) used to detect the pressure parameters inside the tank; the outer tank (102) is also provided with an air inlet for injecting nitrogen or inert gas into the outer tank (102).

7. The vacuum QDR tank according to claim 1, characterized in that, The inner tank (101), outer tank (102), and automatic cover (103) are all made of NPP material. The flow equalization plate (117) has multiple flow equalization holes evenly distributed on it, which are used to convert turbulent fluid into stable and uniform fluid.

8. The vacuum QDR tank according to claim 1, characterized in that, The air extraction device is a vacuum pump. After the vacuum pump is connected to the vacuum suction tube (109), it can form a negative pressure in the sealed cavity. The negative pressure environment can realize the rapid intake of deionized water, the micro-circulation of liquid in the tank and the rapid discharge of waste liquid. After cleaning, the waste liquid is quickly discharged through the quick discharge valve by using the pressure difference between the negative pressure in the tank and the atmospheric pressure.

9. The vacuum QDR tank according to claim 1, characterized in that, The overflow port of the inner tank (101) is a V-shaped overflow port or a U-shaped overflow port opened at the upper end of the inner tank (101). The liquid overflowing from the inner tank (101) can be discharged from the slow drain pipe (105) and / or the fast drain pipe (106) through the overflow chamber.

10. A method of using the vacuum QDR tank according to any one of claims 1-9, characterized in that, Includes the following steps: S1. The wafer cassette is placed in the inner tank (101) of the vacuum QDR tank, and the wafer cassette is precisely positioned by the positioning component; S2. Start the sealing opening and closing assembly, and the automatic cover (103) is driven by the drive component to close and complete the sealing action, so that the inner tank (101) and the outer tank (102) form a closed cavity; S3. Start the vacuum assembly and extract the gas inside the outer tank (102) through the vacuum suction tube (109) on the outer tank (102) to establish and maintain a negative pressure environment inside the outer tank (102); S4. Under negative pressure, deionized water is injected into the inner tank (101) to accelerate the immersion of the wafers on the wafer cassette by using the negative pressure difference, and the spray system is turned on at the same time to perform high-pressure directional spraying to achieve full-area coverage rinsing. S5. Under negative pressure maintenance, a constant liquid level is formed by continuous convection displacement through the overflow port of the inner tank (101) and the overflow cavity. At the same time, the turbulent inflow is rectified into a stable and uniform flow field by means of the flow equalizer (117) to remove chemical residues and particulate contaminants on the wafer surface. S6. After cleaning, immediately open the quick discharge valve on the bottom quick discharge pipe (106). Driven by the pressure difference between the negative pressure inside the outer tank (102) and the external atmospheric pressure, quickly drain the liquid in the tank completely, so that the wafer surface can achieve a dry state without watermarks or oxide layer.

Images