Air tightness detection method after cleaning of substrate storage container and cleaning equipment

Abstract

The invention provides an air tightness detection method for a cleaned substrate storage container. The air tightness detection method comprises the following steps that S1, the cleaned container is transferred to a detection station in cleaning equipment; s2, gas at a first preset temperature is introduced into the closed container at a first preset average flow, so that the internal pressure value of the container reaches a first preset pressure value; s3, maintaining the internal pressure of the container at a first preset pressure value within a first preset duration; s4, in the process of introducing the gas at the first preset temperature into the container in the step S2 and maintaining the internal pressure of the container in the step S3 at the first preset pressure value, continuously detecting heat flow fields on the surface of the container and surrounding areas to obtain detection data; and S5, judging the airtightness of the container according to the detection data. According to the invention, the heated gas is introduced into the container, and the heat flow field information is utilized to realize rapid and accurate detection of the gas tightness of the container.

Description

Technical Field

[0001] This application relates to the field of semiconductor manufacturing technology, and in particular to a method for detecting the airtightness of substrate storage containers. Background Technology

[0002] Substrate storage containers typically require cleaning after use to remove any potential contaminants. With the rapid development of semiconductor manufacturing technology, the requirements for the airtightness of cleaned substrate storage containers are becoming increasingly stringent. On the one hand, if airtightness issues go undetected, moisture may seep into the container during subsequent storage processes, causing the substrate to become damp and affecting its electrical performance and reliability. Moisture can also cause rust and corrosion of metal components on the substrate, shortening its lifespan. On the other hand, dust and other fine particles can also enter the substrate storage container through leaks, contaminating the substrate surface and affecting manufacturing precision and performance. Furthermore, for some special substrates with extremely high environmental requirements, such as wafers manufactured using advanced processes, even minor airtightness defects can lead to serious quality problems and significant economic losses.

[0003] Traditional airtightness testing methods often suffer from low accuracy, complex operation, and low efficiency. For example, some methods may require complex equipment and long testing times, making them unsuitable for the rapid testing needs of large-scale production.

[0004] Therefore, in order to solve the problems existing in the prior art, there is an urgent need for a new method for testing the airtightness of substrate storage containers after cleaning and corresponding cleaning equipment, which can quickly and accurately test the airtightness of substrate storage containers and improve production efficiency and product quality. Summary of the Invention

[0005] In view of this, the present application provides a method for detecting the airtightness of a substrate storage container to solve at least one problem existing in the background art, characterized by comprising the following steps: Step S0: Clean the substrate storage container in the cleaning equipment; Step S1: Transfer the cleaned substrate storage container to the testing station inside the cleaning equipment; Step S2: Open the air inlet of the substrate storage container and close the exhaust port of the substrate storage container at the same time. Introduce gas at a first preset temperature into the sealed substrate storage container at a first preset average flow rate, so that the internal pressure of the substrate storage container reaches a first preset pressure value. The first preset pressure value is greater than the pressure of the environment in which the substrate storage container is located. The first preset temperature is greater than the temperature of the environment in which the substrate storage container is located. Step S3: Maintain the internal pressure of the substrate storage container at a first preset pressure value for a first preset time period. In step S4, during the process of introducing gas at the first preset temperature into the substrate storage container in step S2 and maintaining the internal pressure of the substrate storage container at the first preset pressure value in step S3, the thermal flow field of the substrate storage container surface and surrounding area is continuously detected to obtain detection data. Step S5: Determine the airtightness of the substrate storage container based on the detection data.

[0006] Optionally, step S5 is followed by step S6, in which the air inlet and outlet of the substrate storage container are opened simultaneously, and gas at a second preset temperature is introduced into the substrate storage container at a second preset average flow rate. When the pressure inside the substrate storage container reaches a second preset pressure value, gas at a second preset temperature is continued to be introduced into the sealed substrate storage container at a second preset average flow rate, and gas is discharged from the substrate storage container at a third preset average flow rate, so that the pressure inside the substrate storage container is maintained at a second preset pressure value. The second preset average flow rate is greater than or equal to the first preset average flow rate, and the first preset temperature is greater than or equal to the second preset temperature.

[0007] Optionally, step S4 specifically involves acquiring thermal imaging data of a first preset area using a thermal radiation detection device, wherein the substrate storage container is located within the first preset area, and processing the thermal imaging data to obtain thermal flow field information of the surface of the substrate storage container and its surrounding area.

[0008] Optionally, step S5 specifically involves comparing the thermal flow field information of the substrate storage container surface and surrounding area in the initial state with the thermal flow field information of the substrate storage container surface and surrounding area in the termination state in step S4. When the temperature difference value of the corresponding area in the thermal flow field information of the substrate storage container surface and surrounding area is less than or equal to the second preset threshold, the airtightness of the substrate storage container is determined to be qualified; otherwise, the airtightness of the substrate storage container is determined to be unqualified. The initial state is the state of the substrate storage container when no gas is introduced, and the termination state is the state of the substrate storage container when the internal pressure of the substrate storage container reaches the first preset pressure value.

[0009] Optionally, the first preset average flow rate is set based on the type of the substrate storage container, the material of the substrate storage container, the size of the substrate storage container, and the first preset pressure value.

[0010] Optionally, the first preset average flow rate is 2-50 LPM.

[0011] Optionally, the first preset pressure value is 14.7–25 psi.

[0012] Optionally, the first preset temperature is less than or equal to 80 degrees.

[0013] Optionally, the second preset threshold is set based on the type of the substrate storage container, the first preset temperature, and the first preset pressure value.

[0014] This application also discloses a substrate storage container cleaning device, which adopts the above-described substrate storage container airtightness testing method. The cleaning device includes a loading unit, a processing unit, and a unloading unit. The unloading unit is provided with a testing station for testing the airtightness of the substrate storage container.

[0015] The beneficial effects of this application are as follows: This application introduces a specific flow rate of heated gas into a cleaned substrate storage container and uses thermal imaging technology to detect the external thermal flow field of the substrate storage container for real-time monitoring and acquisition of thermal flow field data. The thermal flow field data is processed according to the state of the introduced gas and the state of the surrounding environment to obtain thermal flow field information, and the sealing status of the substrate storage container is determined based on the thermal flow field information.

[0016] This application ensures that the substrate storage container maintains its airtightness under certain pressure conditions by testing its sealing performance after cleaning. It allows for the timely detection of substrate storage containers with airtightness issues during the cleaning process, thereby preventing subsequent contamination due to poor airtightness. Furthermore, by determining an appropriate test pressure value… Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0017] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the structure of a substrate storage container according to an embodiment of this application; Figure 2 This is a schematic diagram of the substrate storage container cleaning equipment according to an embodiment of this application; Figure 3 This is a thermal imaging image of the substrate storage container in an embodiment of this application when heated gas is not introduced; Figure 4 A thermal imaging image of a substrate storage container with qualified airtightness according to an embodiment of this application after heated gas is introduced; Figure 5The image shows a thermal image of a substrate storage container with poor airtightness according to an embodiment of this application after heated gas is introduced into it. in: 1. Loading unit; 2. Processing unit; 3. Unloading unit; 301. Loading station; 302. Unloading station a1. Cover; 2. Box body; a201. Air inlet; a201. Exhaust outlet Detailed Implementation

[0018] Exemplary embodiments of the present application will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application may be implemented in various forms and should not be limited to the specific embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present application and to fully convey the scope of the disclosure of the present application to those skilled in the art.

[0019] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of this application. However, it will be apparent to those skilled in the art that this application can be practiced without one or more of these details. In other instances, to avoid confusion with this application, some technical features well-known in the art have not been described; that is, not all features of actual embodiments are described herein, nor are well-known functions and structures described in detail.

[0020] In the accompanying drawings, for clarity, the dimensions of layers, areas, and elements, as well as their relative dimensions, may be exaggerated. The same reference numerals denote the same elements throughout.

[0021] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this application, the first element, component, area, layer, or portion discussed below may be referred to as a second element, component, area, layer, or portion. And the discussion of a second element, component, area, layer, or portion does not imply that the first element, component, area, layer, or portion necessarily exists in this application.

[0022] Spatial relation terms such as “below,” “under,” “below,” “below,” “above,” “above,” etc., are used herein for convenience of description to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms are intended to also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, then the element or feature described as “below” or “below” other elements or features will be oriented “above” other elements or features. Therefore, the exemplary terms “below” and “under” can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or otherwise) and the spatial descriptive terms used herein will be interpreted accordingly.

[0023] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising” and / or “including,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0024] To fully understand this application, detailed steps and structures will be presented in the following description to illustrate the technical solution of this application. Preferred embodiments of this application are described in detail below; however, in addition to these detailed descriptions, this application may have other implementation methods.

[0025] like Figure 1 As shown in the embodiments of this application, the substrate storage container includes a separable cover a1 and a housing a2. During wafer transport, the cover and housing are locked together. During cleaning of the substrate storage container, the housing and cover are unlocked and placed in the same cleaning chamber for cleaning. After cleaning, the housing and cover are relocked together. One side wall of the substrate storage container is provided with an air inlet a201 and an exhaust outlet a201. The air inlet is connected to a gas supply assembly to introduce gas into the substrate storage container, and the exhaust outlet is connected to a gas discharge assembly to discharge gas from the substrate storage container.

[0026] In one optional embodiment, the vent of the substrate storage container is provided with a pressure relief valve, which releases the gas inside the substrate storage container when the internal pressure reaches a set value.

[0027] like Figure 2As shown in the figure, this application provides a substrate storage container cleaning device. The cleaning device includes a loading unit 1, a processing unit 2 and a unloading unit 3. The unloading unit is provided with a detection station for detecting the airtightness of the substrate storage container.

[0028] In this embodiment, the processing unit includes a cleaning chamber. The substrate storage container to be cleaned is fed into the loading unit via an external transfer mechanism. After relevant identification and detection in the loading unit, the substrate storage container is sent to the cleaning chamber for processing. In the cleaning unit, the unlocking mechanism unlocks the substrate storage container, separating the box and the cover. The cleaning fluid removes contaminants adhering to the inner wall of the substrate storage container. After the substrate storage container is cleaned, the unlocking mechanism locks the substrate storage container back into a sealed state. Finally, the cleaned substrate storage container is sent to the unloading unit, which includes a loading station 301 located inside the cleaning equipment and an unloading station 302 located outside the cleaning equipment. The substrate storage container is transferred between the loading station and the unloading station via a conveyor track. Relevant detection components are integrated into the loading station. After the substrate storage container completes detection at the loading station, it is unloaded.

[0029] In this embodiment, the inspection station is integrated into the unloading station of the unloading unit. The inspection station is equipped with a fixing component for fixing the substrate storage container, a gas supply component for introducing gas into the substrate storage container, a gas discharge component for discharging gas from the substrate storage container, a thermal imaging device for capturing thermal flow field data of the substrate storage container and the surrounding area, and a control component for controlling the operation of other components.

[0030] It is understandable that heated gas is introduced into the substrate storage container through the gas supply component, and the presence of poor airtightness in the substrate storage container is detected by the thermal imaging equipment. Based on this, gas is introduced into the substrate storage container through the gas supply component and discharged from the substrate storage container through the gas emission component, thereby increasing the gas exchange in the substrate storage container and reducing the humidity level in the substrate storage container.

[0031] In another alternative embodiment, the processing unit further includes a drying chamber.

[0032] After being cleaned and pre-treated in the cleaning chamber, the substrate storage container is sent to the drying chamber to further reduce the humidity level inside the substrate storage container.

[0033] This application provides a method for testing the airtightness of a substrate storage container after cleaning, characterized by including the following steps: Step S0: Clean the substrate storage container in the cleaning equipment; In this step, the substrate storage container is disassembled into a box and a cover, and then sent to different processing units for processing to ensure that the residual level of contaminants inside meets the cleaning requirements. After cleaning, the box and cover are then relocked.

[0034] Step S1: Transfer the cleaned substrate storage container to the testing station inside the cleaning equipment; In this step, the cleaned substrate storage container is transferred to the inspection station in the unloading unit by the robot inside the equipment. The substrate storage container is inspected at the inspection station to detect and identify defective substrate storage containers, thus preventing defective substrate storage containers from flowing into the next process.

[0035] Step S2: Open the air inlet of the substrate storage container and close the exhaust port of the substrate storage container at the same time. Introduce gas at a first preset temperature into the sealed substrate storage container at a first preset average flow rate, so that the internal pressure of the substrate storage container reaches a first preset pressure value. The first preset pressure value is greater than the pressure of the environment in which the substrate storage container is located, and the first preset temperature is greater than the temperature of the environment in which the substrate storage container is located. In this step, a certain volume of gas at a specific temperature is introduced into the substrate storage container to bring its internal pressure to a first preset pressure value. If there is a problem with the airtightness of the substrate storage container at this time, the gas will escape from the leak point. Since the temperature of the gas inside the substrate storage container is higher than the ambient temperature, it is easy for the detection equipment to identify it.

[0036] Understandably, during the transfer of a substrate storage container containing the substrate, it is necessary to inflate the container to maintain a positive pressure inside, preventing external contaminants from entering. However, if this positive pressure is broken due to airtightness issues, the difficulty of external contaminants entering the container is significantly reduced. Therefore, to maintain a stable positive pressure while storing the substrate, the airtightness of the substrate storage container must be ensured.

[0037] In this step, a certain volume of gas is injected into the substrate storage container to bring the internal pressure of the substrate storage container to a preset value. By setting an appropriate preset value, the airtightness of the substrate storage container under a specific pressure is tested, thereby ensuring that the substrate storage container that passes the test can maintain a stable positive pressure state inside during subsequent use, thus preventing contaminants from the outside of the substrate storage container from entering the interior of the substrate storage container.

[0038] Step S3: Maintain the internal pressure of the substrate storage container at a first preset pressure value for a first preset time period. Compared to step S2, in this step, the pressure inside the substrate storage container is maintained at a first preset pressure value for a period of time, allowing the detection device sufficient time to sense minute pressure changes, thereby improving the accuracy of the detection. Furthermore, by adding a pressure-holding step, interference from external environmental factors, such as temperature changes and air pressure fluctuations, can be effectively filtered out. These factors may cause instability in the pressure readings, thus affecting the accuracy of the detection results.

[0039] Step S4: During the process of introducing gas at the first preset temperature into the substrate storage container in step S2 and maintaining the internal pressure of the substrate storage container at the first preset pressure value in step S3, the thermal flow field of the surface and surrounding area of ​​the substrate storage container is continuously detected to obtain detection data. In this step, the thermal flow field of the substrate storage container and its surrounding area is continuously detected in steps S2 and S3, and analyzed by the control component to obtain information on the changes in the thermal flow field of the space around the substrate storage container.

[0040] Step S4: Determine the airtightness of the substrate storage container based on the detection data.

[0041] It is understandable that, since the temperature of the gas inside the substrate storage container is higher than that of the external environment, when there is a leak in the substrate storage container, the thermal flow field of the external area of ​​the substrate storage container will change significantly. Therefore, by real-time detection of the thermal flow field on the surface of the substrate storage container and the surrounding area, the airtightness of the substrate storage container under a specific pressure can be accurately reflected.

[0042] In the prior art, in order to ensure the cleanliness of the substrate storage container, the substrate storage container (or the cleaned substrate storage container) containing the semiconductor substrate is generally filled with nitrogen. By introducing a certain volume of nitrogen into the substrate storage container, a positive pressure is maintained inside the substrate storage container to prevent contaminants from the outside of the substrate storage container from entering the substrate storage container and causing contamination to the substrate.

[0043] When contamination tests were conducted on substrates placed inside substrate storage containers after treatment using the aforementioned method, significant differences in the residual contaminant values ​​on the substrate surfaces of different substrate storage containers were observed. The inventors, through long-term research, discovered that because substrate storage containers consist of a lid and a casing, which are typically made of polymer materials such as PC, COPPC, CBM, and PEI, these components undergo varying degrees of aging and deformation after a period of use. This also affects the seals between the lid and casing, leading to a decrease in the sealing performance of the substrate storage container. When substrates are stored in substrate storage containers with sealing issues, even if the container is initially under positive pressure, the internal pressure gradually decreases over time, disrupting the positive pressure environment. This allows external contaminants to easily enter and contaminate the container, ultimately contaminating the substrates placed inside. Therefore, even if the residual contaminants in the cleaned substrate storage container meet the storage requirements, they will exceed the acceptable limits after a certain period of storage.

[0044] Therefore, after cleaning the substrate storage container, the sealing performance of the substrate storage container is tested to ensure that the sealing performance of the substrate storage container after cleaning can maintain the positive pressure environment inside the substrate storage container, thereby improving the cleanliness of the substrate storage container after cleaning and preventing the substrate placed inside the substrate storage container from being contaminated.

[0045] This embodiment tests the sealing performance of the substrate storage container during the substrate storage container unloading process. By introducing heated air into the substrate storage container, the pressure value of the substrate storage container is made between the pressure value required for storage and the maximum pressure value that the substrate storage container can withstand. By monitoring the heat flow field of the space around the substrate storage container, the gas overflow information inside the substrate storage container is obtained, and then the sealing performance of the substrate storage container is evaluated.

[0046] Understandably, to improve the cleaning efficiency of cleaning equipment, it is necessary to quickly test the airtightness of the substrate storage container. Generally, after cleaning, a certain amount of gas needs to be injected into the substrate storage container to maintain a positive pressure state inside, preventing contamination of the cleaned container. In this embodiment, thermal imaging technology is used to detect the substrate storage container during the gas injection process. The airtightness test can be completed during the gas injection process. Compared to conventional substrate storage container cleaning methods that do not perform airtightness testing, the airtightness test in this embodiment does not consume additional testing time, thereby improving the cleaning efficiency of the substrate storage container.

[0047] In one optional embodiment, the first preset average flow rate is set based on the type of the substrate storage container, the material of the substrate storage container, the size of the substrate storage container, and the first preset pressure value.

[0048] Understandably, the first average flow rate determines the time required for the internal pressure of the substrate storage container to reach a first preset pressure value during the inflation process. Therefore, the larger the first average flow rate, the shorter the time required to inflate the substrate storage container. However, the applicant discovered in multiple experiments that, due to the inherent characteristics of the substrate storage container, when the first average flow rate exceeds a certain extreme value, even if the substrate storage container does not have an airtightness issue, some leakage will still occur during the inflation process. Because the gas distribution inside the substrate storage container is uneven at a certain moment during the infusion of gas at a large flow rate, the gas pressure at a certain point in the substrate storage container is greater than the gas pressure in other areas. When the local gas pressure exceeds the limit that the substrate storage container can withstand, deformation occurs at the connection between the cover and the casing, and the gas inside the substrate storage container leaks out from the deformation point, leading to an incorrect judgment of poor sealing of the substrate storage container.

[0049] Therefore, different types of substrate storage containers determine the pressure value required at the location of the substrate storage container during storage, the volume of the substrate storage container determines the time required to fill the substrate storage container with gas, and the material of the substrate storage container determines the maximum instantaneous pressure that the inner wall of the substrate storage container can withstand. By selecting an appropriate first preset average flow rate value, the efficiency of filling the substrate storage container with gas can be ensured while avoiding large airflows that could cause deformation of the substrate storage container, thereby affecting the airtightness of the substrate storage container.

[0050] In one alternative embodiment, the first preset average flow rate is 2-50 LPM.

[0051] By setting an appropriate first preset average flow rate, the time required for the internal pressure of the substrate storage container to reach the first preset pressure value is reduced, thereby improving the detection effect of the substrate storage container's airtightness. Taking a first preset pressure value of 17 psi as an example, when the air inlet flow rate of the substrate storage container is less than 2 LPM during testing, the time required for the substrate storage container to reach the first preset pressure value will be greater than 2 minutes. Generally, the cleaning time for a single substrate storage container in the cleaning equipment is about 2-3 minutes. A detection time greater than 2 minutes will greatly affect the cleaning efficiency of the substrate storage container. Furthermore, the air inlet of the substrate storage container usually limits the air inlet flow rate. When the air inlet flow rate of the substrate storage container is greater than 50 LPM during testing, the large air inlet flow rate will damage the air inlet, affecting the airtightness of the substrate storage container. On the other hand, if the time for introducing heated gas into the substrate storage container during the testing process exceeds 2 minutes, the container is easily heated to near the temperature of the gas itself, thereby increasing the difficulty of judging the airtightness of the container in subsequent processes and reducing the accuracy of the test. It is understood that the method of this embodiment detects the airtightness of the substrate storage container by comparing the temperature changes of its surface and surrounding area before and after gas is introduced. When the temperature of the substrate storage container itself rises, even if the airtightness of the substrate storage container itself is not a problem, the substrate storage container will be judged as unqualified for airtightness during the detection process because the temperature of the substrate storage container after gas filling is much higher than the temperature of the container itself when it is not filled.

[0052] In a preferred embodiment, the first preset average flow rate is 10-40 LPM.

[0053] In an alternative embodiment, the first preset pressure value is 14.7–25 psi.

[0054] In this embodiment, the purpose of performing an airtightness test on the substrate storage container is to prevent external contaminants from entering the container during storage. Therefore, a first preset pressure value needs to be determined based on the internal pressure of the substrate storage container during storage. This first preset pressure value is set to be greater than or equal to the internal pressure of the substrate storage container during storage, and the airtightness of the substrate storage container is tested based on this value. This ensures that substrate storage containers that pass the airtightness test will not leak during storage, and that the internal pressure of the substrate storage container can be stably maintained at a positive pressure, preventing external contaminants from entering the container. Generally, the internal pressure of the substrate storage container during storage and transportation is greater than or equal to 14.7 psi. Therefore, the minimum first preset pressure value is 14.7 psi when performing an airtightness test on the substrate storage container.

[0055] Understandably, since the airtightness test of the substrate storage container only needs to ensure that there will be no internal gas leakage during subsequent use, the internal pressure of the substrate storage container should not be too high during the airtightness test. When the internal pressure of the substrate storage container exceeds 25 psi, even if there is no risk of leakage during subsequent use, the internal pressure of the substrate storage container will still leak to the outside of the substrate storage container at a certain flow rate during the test. Therefore, the substrate storage container will still fail the airtightness test. That is, if the first preset pressure value is too high, it will affect the accuracy of the test. More seriously, due to the characteristics of the substrate storage container itself, when the internal pressure is greater than 42 psi, the air inlet, air outlet, and the joint between the cover and the box of the substrate storage container may deform. This deformation is generally irreversible. If the inside of the substrate storage container is under this pressure state for a long time, it will cause irreversible damage to the substrate storage container. On the other hand, some are equipped with pressure relief ports for active venting. When the pressure of the substrate storage container reaches the pressure relief port, the gas will be discharged from the pressure relief port. Therefore, when performing airtightness testing on the substrate storage container, the test pressure needs to be less than the pressure relief port.

[0056] In a preferred embodiment, the first preset pressure value is 15.2-18 psi.

[0057] In an optional embodiment, the first preset temperature is less than or equal to 80 degrees and greater than or equal to the ambient temperature of the substrate storage container.

[0058] Understandably, due to the inherent limitations of the substrate storage container material, as the temperature inside the substrate storage container increases, the rigidity and yield strength of the inner wall of the substrate storage container will decrease. At this time, under the action of external force, the inner wall of the substrate storage container is prone to deformation, which will cause gas to escape from the substrate storage container, affecting the accuracy of the airtightness test of the substrate storage container. When the temperature of the gas introduced into the substrate storage container is greater than 80 degrees Celsius, when the pressure value inside the substrate storage container reaches the first preset pressure value, due to the deformation of the inner wall of the substrate storage container, the gas inside the substrate storage container will escape from the deformation point of the inner wall of the substrate storage container, affecting the accuracy of the airtightness test results of the substrate storage container.

[0059] In another preferred embodiment, the first preset temperature is greater than or equal to 45 degrees Celsius and less than or equal to 70 degrees Celsius.

[0060] In one optional embodiment, the first preset duration is 5-30 seconds.

[0061] In an optional embodiment, step S4 specifically involves acquiring thermal imaging data of a first preset area using a thermal radiation detection device, wherein the substrate storage container is located within the first preset area, and processing the thermal imaging data to obtain thermal flow field information of the surface of the substrate storage container and its surrounding area.

[0062] In this embodiment, during the process of introducing gas into the substrate storage container and maintaining the internal pressure of the substrate storage container at a first preset pressure value, data within a first preset area is continuously acquired by a thermal imaging device. As hot air is introduced into the substrate storage container, the surface temperature of the substrate storage container begins to rise, and the substrate storage container emits thermal radiation to the surrounding area. When gas leaks out from inside the substrate storage container, the thermal flow field of the environment around the substrate storage container changes. Similarly, the thermal radiation at the point where the gas leaks out on the surface of the substrate storage container also changes. However, this leak point is generally located at the junction of the box and the cover. If there are other components blocking this point, the thermal imaging device cannot directly capture the image at the leak point. Therefore, to ensure the accuracy of the detection, the thermal imaging device needs to simultaneously capture the thermal flow field data of the surface of the substrate storage container and the environment around the substrate storage container.

[0063] In one alternative embodiment, the thermal imaging device is an online infrared thermal imager.

[0064] In the above embodiments, the thermal imaging data is image data and / or video data.

[0065] In one optional embodiment, the substrate storage container occupies more than 85% of the first preset area.

[0066] Understandably, after acquiring thermal flow field data, thermal imaging equipment needs to process it to obtain thermal flow field information that can assess the airtightness of the substrate storage container. To ensure the processing efficiency of thermal imaging data, it is necessary to increase the proportion of the substrate storage container within the first preset area. At the same time, to ensure detection accuracy, it is necessary to capture as many images as possible of the area surrounding the substrate storage container. Therefore, having the substrate storage container occupy more than 85% of the first preset area can simultaneously achieve both detection efficiency and detection accuracy.

[0067] In an optional embodiment, step S5 specifically involves comparing the thermal flow field information of the substrate storage container surface and surrounding area in the initial state with the thermal flow field information of the substrate storage container surface and surrounding area in the termination state in step S4. When the temperature difference values ​​of the corresponding areas in the thermal flow field information of the substrate storage container surface and surrounding area are all less than or equal to the second preset threshold, the airtightness of the substrate storage container is determined to be qualified; otherwise, the airtightness of the substrate storage container is determined to be unqualified. The initial state is the state of the substrate storage container when no gas is introduced, and the termination state is the state of the substrate storage container after the internal pressure of the substrate storage container reaches the first preset pressure value and is maintained at the pressure value for the first preset time.

[0068] In this embodiment, the space where the container is located is divided into several regions according to the actual detection accuracy requirements. The higher the detection accuracy requirement, the more regions are divided. Generally, the space where the substrate storage container is located is divided into 9 square regions of equal size in a nine-square grid manner. By obtaining the heat flow field information of the substrate storage container surface and surrounding area in the initial state, that is, the heat flow field information of the substrate storage container surface and surrounding area before the heated gas is introduced, and comparing it with the heat flow field information of the substrate storage container surface and surrounding area after the gas is introduced, the airtightness of the substrate storage container is evaluated.

[0069] It is understandable that the substrate storage container, after being heated by the gas, will also emit thermal radiation. This thermal radiation will affect the thermal flow field of the surrounding environment. By setting a second preset threshold, the interference of the substrate storage container's thermal radiation on the test results can be effectively filtered, improving the accuracy of the test. On the other hand, during the airtightness test of the substrate storage container, we allow a certain amount of gas leakage within the container. That is, when the total volume of gas leakage within the container is less than a preset volume and the instantaneous flow rate of gas leakage is less than a preset flow rate, the airtightness of the substrate storage container can be judged to be qualified. Therefore, in the process of judging the airtightness of the substrate storage container through thermal flow field information, when the thermal flow field outside the container changes due to a small amount of gas leakage, by setting a reasonable second preset threshold, as long as the temperature difference in the corresponding area of ​​the thermal flow field information is less than the second preset threshold, the airtightness of the substrate storage container can be judged to be qualified.

[0070] In one optional embodiment, the second preset threshold is set based on the type of the substrate storage container, the first preset temperature, and the first preset pressure value.

[0071] Understandably, on the one hand, different types of substrate storage containers emit different amounts of thermal radiation at specific temperatures; similarly, different first preset temperatures result in varying amounts of heat generated when gas is introduced into the substrate storage container. Therefore, setting a second preset threshold based on the type of substrate storage container and the first preset temperature can further improve detection accuracy. On the other hand, when the gas pressure inside a well-sealed substrate storage container reaches the first preset pressure value, a certain amount of gas leakage will occur. The higher the first preset pressure value, the greater the allowable leakage during detection. Therefore, the second preset threshold needs to be revised based on the first preset pressure value to further improve detection accuracy. In this embodiment, the second preset threshold is set comprehensively based on the type of substrate storage container, the first preset temperature, and the first preset pressure value, which can improve detection accuracy and avoid misjudging a substrate storage container with acceptable airtightness as one with unacceptable airtightness.

[0072] In this embodiment, when performing airtightness testing on substrate storage containers of different types, different first preset temperatures, and different first preset pressure values, the second preset threshold can be set with reference to the table below.

[0073]

[0074] When the substrate storage container is a FOUP made of PC material and the ambient temperature of the substrate storage container is 26 degrees Celsius, the first preset pressure value is set to 17.0 psi, the first preset temperature value is set to 55 degrees Celsius, the second preset threshold value is set to 15 degrees Celsius, and the first preset duration is set to 10 seconds.

[0075] like Figure 3 As shown, when heated gas is not introduced into the substrate storage container, i.e., the initial state described in this embodiment, the average temperature of each area of ​​the container is recorded.

[0076] like Figure 4 As shown, if the airtightness of the substrate storage container is qualified, when the internal pressure value of the substrate storage container reaches 17.0 psi and is maintained for 10 seconds, the thermal flow field information of the surface and surrounding area of ​​the substrate storage container changes due to the heating effect of the substrate storage container. However, at the termination state, the temperature difference of each area of ​​the container is less than the second preset threshold.

[0077] like Figure 5As shown, if the airtightness of the substrate storage container fails to meet the test, when the internal pressure of the substrate storage container reaches 17.0 psi and is maintained at a secondary pressure value for 10 seconds, the thermal flow field information of the surface and surrounding area of ​​the substrate storage container changes due to the heat of the substrate storage container. Since some gas overflows from the leak point (the junction of the cover and the box), the temperature of that area rises rapidly, causing the temperature difference in that area to be greater than the second preset threshold at the termination state.

[0078] In an optional embodiment, step S5 is followed by step S6, which involves maintaining the air inlet of the substrate storage container in an open state and the air outlet in a closed state, introducing gas at a second preset temperature into the substrate storage container at a second preset average flow rate, and continuing to introduce gas at the second preset temperature into the sealed substrate storage container at a second preset average flow rate when the pressure inside the substrate storage container reaches a second preset pressure value, while opening the air outlet of the substrate storage container to discharge the gas inside the substrate storage container at a third preset average flow rate, thereby maintaining the pressure inside the substrate storage container at the second preset pressure value, wherein the second preset average flow rate is greater than or equal to the first preset average flow rate, and the first preset temperature is greater than or equal to the second preset temperature.

[0079] After the airtightness test of the substrate storage container is completed, gas is continuously introduced into the substrate storage container until the internal pressure reaches the second preset pressure value. The gas supply to the substrate storage container is maintained, and excess gas is discharged through the exhaust port. This accelerates the gas exchange rate inside the substrate storage container, speeds up the evaporation of moisture inside the substrate storage container, and carries the evaporated moisture away from the inside of the substrate storage container through the gas discharge, thereby achieving the purpose of reducing the humidity inside the substrate storage container.

[0080] In the above embodiment, the second preset pressure value is the pressure relief pressure of the exhaust port of the substrate storage container. When the internal pressure of the substrate storage container reaches the second preset pressure value, the exhaust port of the substrate storage container opens, and the gas inside the substrate storage container is discharged from the exhaust port to the outside of the substrate storage container.

[0081] In one optional embodiment, the humidity of the gas discharged from the substrate storage container is detected, and when the humidity of the gas discharged from the substrate storage container is lower than a third preset threshold, the gas is stopped from being pumped into the substrate storage container.

[0082] In the above embodiment, the third preset threshold is set to 5%.

[0083] In the above embodiment, the second preset average flow rate is 30-80 LPM.

[0084] In the above embodiment, the second preset temperature is 45-70 degrees Celsius.

[0085] In an optional embodiment, by detecting the humidity of the gas discharged from the substrate storage container, when the humidity of the gas discharged from the substrate storage container is lower than a fourth preset threshold, gas at a third preset temperature is introduced into the substrate storage container at a second preset average flow rate.

[0086] In this embodiment, the third preset temperature is 25-30 degrees Celsius.

[0087] Understandably, if the temperature of the cleaned substrate storage container is much higher than the ambient temperature (the air temperature inside the substrate storage container is more than 20 degrees Celsius higher than the ambient temperature), after a period of time, when the temperature of the substrate storage container drops to near the ambient temperature, due to thermal expansion and contraction, the volume of gas inside the substrate storage container decreases, resulting in a decrease in the internal pressure of the substrate storage container. This increases the possibility of external contaminants entering the substrate storage container. On the other hand, due to condensation, condensation water is easily generated inside the substrate storage container and in the surrounding area, which can affect the substrate storage container.

[0088] It should be understood that the above embodiments are exemplary and are not intended to encompass all possible implementations included in the claims. Various modifications and changes can be made to the above embodiments without departing from the scope of this disclosure. Similarly, the various technical features of the above embodiments can be arbitrarily combined to form other embodiments of this application that may not be explicitly described. Therefore, the above embodiments only illustrate several implementations of this application and do not limit the scope of protection of this patent application.

Claims

1. A method for testing the airtightness of a substrate storage container after cleaning, characterized in that, Includes the following steps: Step S0: Clean the substrate storage container in the cleaning equipment; Step S1: Transfer the cleaned substrate storage container to the testing station inside the cleaning equipment; Step S2: Open the air inlet of the substrate storage container and close the exhaust port of the substrate storage container at the same time. Introduce gas at a first preset temperature into the sealed substrate storage container at a first preset average flow rate, so that the internal pressure of the substrate storage container reaches a first preset pressure value. The first preset pressure value is greater than the pressure of the environment in which the substrate storage container is located, and the first preset temperature is greater than the temperature of the environment in which the substrate storage container is located. Step S3: Maintain the internal pressure of the substrate storage container at a first preset pressure value for a first preset time period. In step S4, during the process of introducing gas at the first preset temperature into the substrate storage container in step S2 and maintaining the internal pressure of the substrate storage container at the first preset pressure value in step S3, the thermal flow field of the substrate storage container surface and surrounding area is continuously detected to obtain detection data. Step S5: Determine the airtightness of the substrate storage container based on the detection data.

2. The method for detecting the airtightness of a substrate storage container after cleaning according to claim 1, characterized in that: Step S5 is followed by step S6, which involves maintaining the air inlet of the substrate storage container in an open state and the air outlet in a closed state, introducing gas at a second preset temperature into the substrate storage container at a second preset average flow rate, and continuing to introduce gas at a second preset temperature into the sealed substrate storage container at a second preset average flow rate when the pressure inside the substrate storage container reaches a second preset pressure value, while opening the air outlet of the substrate storage container to discharge the gas inside the substrate storage container at a third preset average flow rate, so that the pressure inside the substrate storage container is maintained at the second preset pressure value, wherein the second preset average flow rate is greater than or equal to the first preset average flow rate, and the first preset temperature is greater than or equal to the second preset temperature.

3. The method for detecting the airtightness of a substrate storage container after cleaning according to claim 1, characterized in that: Specifically, step S4 involves acquiring thermal imaging data of a first preset area using a thermal radiation detection device, wherein the substrate storage container is located within the first preset area, and processing the thermal imaging data to obtain thermal flow field information of the surface of the substrate storage container and its surrounding area.

4. The method for detecting the airtightness of a substrate storage container after cleaning according to claim 3, characterized in that: Specifically, step S5 involves comparing the thermal flow field information of the substrate storage container surface and surrounding area in the initial state with that in the termination state in step S4. When the temperature difference in the corresponding area of ​​the thermal flow field information of the substrate storage container surface and surrounding area is less than or equal to a second preset threshold, the airtightness of the substrate storage container is determined to be qualified; otherwise, the airtightness of the substrate storage container is determined to be unqualified. The initial state is the state of the substrate storage container when no gas is introduced, and the termination state is the state of the substrate storage container when the internal pressure of the substrate storage container reaches a first preset pressure value.

5. The method for detecting the airtightness of a substrate storage container after cleaning according to claim 1, characterized in that: The first preset average flow rate is set based on the type of the substrate storage container, the material of the substrate storage container, the size of the substrate storage container, and the first preset pressure value.

6. The method for detecting the airtightness of a substrate storage container after cleaning according to claim 5, characterized in that: The first preset average flow rate is 2-50 LPM.

7. The method for detecting the airtightness of a substrate storage container after cleaning according to claim 1, characterized in that: The first preset pressure value is 14.7-25 psi.

8. The method for detecting the airtightness of a substrate storage container after cleaning according to claim 1, characterized in that: The first preset temperature is less than or equal to 80 degrees Celsius.

9. The method for detecting the airtightness of a substrate storage container after cleaning according to claim 4, characterized in that: The second preset threshold is set based on the type of the substrate storage container, the first preset temperature, and the first preset pressure value.

10. A substrate storage container cleaning device, characterized in that: The method for testing the air tightness of a substrate storage container as described in any one of claims 1-9 is used. The cleaning equipment includes a loading unit, a processing unit, and a unloading unit. The unloading unit is provided with a testing station for testing the air tightness of the substrate storage container.

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