Wafer temporary storage device and vertical furnace

Abstract

This invention provides a wafer temporary storage device and a vertical furnace. The temporary storage chamber integrates a cleaning module, which can clean non-product wafers in situ, avoiding the time-consuming, particulate contamination, and equipment occupation problems caused by sending non-product wafers out for cleaning, and ensuring that non-product wafers are continuously kept in a clean state. It can flexibly provide clean non-product wafers to fill the empty spaces according to the number of product wafers, so that the total number of product wafers and non-product wafers entering the subsequent processes in each batch is a preset value and remains consistent. Production can start without waiting for a full batch of product wafers, effectively improving the utilization rate of the vertical furnace. It eliminates the need for frequent adjustments to process parameters due to filling empty spaces, reducing the risk of process fluctuations and the workload of personnel, and achieving stable, efficient, and high-cleanliness batch production.

Description

Technical Field

[0001] This invention relates to the field of semiconductor equipment technology, and more particularly to a wafer temporary storage device and a vertical furnace. Background Technology

[0002] Currently, when using vertical diffusion furnaces for processes such as Chemical Vapor Deposition (CVD), the process results (film deposition rate and thickness, as well as thermal oxidation rate and thickness) are affected by wafer surface condition, pattern density, total exposed area of ​​all wafers in the reaction chamber, and the loading effect. The physical and chemical root cause lies in the disruption of the dynamic balance between the supply and consumption of reactant gases or reactants. Specifically, the loading effect primarily impacts process results in decreased intra-wafer uniformity, decreased inter-wafer uniformity, and decreased batch-to-batch repeatability.

[0003] To mitigate the impact of loading effects on process results, a common approach is to maintain a constant number of product wafers, ensuring the number of wafers in the reaction chamber remains consistent throughout each production run. However, in actual production, some batches may contain fewer than 25 wafers. In such cases, it's necessary to wait for other batches of product wafers or transfer non-product wafers from external sources to replenish the 25-wafer quantity requirement, which wastes machine uptime. Another method is to adjust process parameters to minimize the impact of loading effects, but this requires adjustments every time, increasing system risk and personnel workload.

[0004] Therefore, it is necessary to provide a new type of wafer temporary storage device and vertical furnace to solve the above-mentioned problems existing in the prior art. Summary of the Invention

[0005] The purpose of this invention is to provide a wafer storage device and a vertical furnace, which can accommodate any batch of product wafers by filling the empty spaces with non-product wafers located inside the device, and integrate a cleaning module in the wafer storage device to realize in-situ cleaning of non-product wafers in the device, thereby reducing the time consumption and particle contamination risk of outsourced cleaning.

[0006] To achieve the above objectives, the wafer temporary storage device of the present invention is applied to a vertical furnace, the vertical furnace including a loading cavity, and the wafer temporary storage device comprising: The main body of the temporary storage chamber forms an internal temporary storage chamber; A wafer transfer module is disposed on the main body of the temporary storage cavity and is used to switch the transmission path between the temporary storage cavity and the loading cavity to a connected state or a blocked state. Several first temporary storage sub-modules are disposed in the temporary storage cavity for storing product wafers; A cleaning module, disposed within the temporary storage chamber, is used to clean non-product wafers and provide cleaned non-product wafers according to the number of product wafers, so that the total number of product wafers and non-product wafers undergoing subsequent processes in each batch is a preset value; and, A gas transmission module, connected to the cleaning module, is used to deliver cleaning gas into the cleaning module.

[0007] Optionally, the cleaning module includes a cleaning chamber and N support plates, wherein the N support plates are sequentially arranged on the inner wall of the cleaning chamber along a direction perpendicular to the horizontal plane, and N is a natural number greater than or equal to 1. The gas transmission module includes a main pipe, N secondary pipes, N flow valves, and N gas spray heads. One gas spray head is located at the top center of the cleaning chamber. The remaining N-1 gas spray heads correspond one-to-one with N-1 support plates from top to bottom and are located below the middle area of ​​the corresponding support plate. One end of each of the N secondary pipes is connected to one of the N gas spray heads, and the other end of each of the N secondary pipes is connected to one end of the main pipe. The other end of the main pipe is used to connect to the cleaning gas supply unit. Each flow valve corresponds one-to-one with a secondary pipe and is located on the corresponding secondary pipe.

[0008] Optionally, the cleaning module includes a cleaning chamber and a wafer carrier device; the wafer carrier device is erected in the cleaning chamber, and the wafer carrier device includes multiple spaced columns and a top plate and / or a bottom plate located at the ends of the multiple columns. The columns are spaced apart from bottom to top with multiple grooves, and the grooves of the multiple columns on the same horizontal plane constitute the bearing position for the wafer.

[0009] Optionally, the wafer carrier is detachably disposed within the cleaning chamber.

[0010] Optionally, the cleaning module further includes a cleaning chamber isolation door and a cleaning chamber opening mechanism. The cleaning chamber has a cleaning chamber transmission port, which is connected to the loading chamber. The cleaning chamber isolation door is disposed on the cleaning chamber transmission port. The cleaning chamber opening mechanism is disposed on the outer wall of the cleaning chamber and connected to the cleaning chamber isolation door, and is used to open or close the cleaning chamber isolation door.

[0011] Optionally, the wafer temporary storage device further includes at least one second temporary storage sub-module. The second temporary storage sub-module is disposed in the temporary storage cavity and is used to store non-product wafers. Both the first temporary storage sub-module and the second temporary storage sub-module include a sub-temporary storage cavity body and a sub-temporary storage cavity isolation door. The sub-temporary storage cavity body is provided with a wafer access port, and the sub-temporary storage cavity isolation door is disposed on the wafer access port.

[0012] Optionally, the wafer temporary storage device further includes a support module and a module transfer robot. The support module is disposed in the temporary storage cavity and is used to support the first temporary storage sub-module and the second temporary storage sub-module, and is detachably connected to both. The module transfer robot is disposed in the temporary storage cavity and is used to transfer the first temporary storage sub-module and the second temporary storage sub-module between the support module and the wafer transfer module.

[0013] Optionally, the bottom of the sub-temporary storage chamber body is provided with a positioning mechanism. The support module includes a support frame, a plurality of bearing platforms, and positioning and cooperating mechanisms corresponding to each bearing platform. The bearing platforms are fixedly disposed on the support frame and are used to support the first temporary storage sub-module and the second temporary storage sub-module. The positioning and cooperating mechanisms are disposed on the bearing platforms and cooperate with the positioning mechanism to position the first temporary storage sub-module and the second temporary storage sub-module to prevent the positions of the first temporary storage sub-module and the second temporary storage sub-module from shifting. And / or, The top center of the sub-temporary storage cavity body is provided with a clamping engagement part, which is adapted to the clamping end of the module transfer robot for clamping by the module transfer robot to transfer the first temporary storage sub-module and the second temporary storage sub-module.

[0014] Optionally, the cleaning gas includes an etching gas and a purge gas; when the cleaning module cleans the non-product wafer, the gas transmission module supplies at least the etching gas to the cleaning module; before removing the non-product wafer from the cleaning module, the gas transmission module supplies the purge gas to the cleaning module so that the environment within the cleaning module meets the transport conditions of the non-product wafer.

[0015] The present invention also provides a vertical furnace, including a furnace body, a loading cavity, and a wafer temporary storage device as described in any of the above embodiments. The furnace body and the wafer temporary storage device are both connected to the loading cavity. The loading cavity is provided with a loading cavity robotic arm for transferring product wafers and non-product wafers to a wafer boat for feeding into the furnace for processing.

[0016] The beneficial effects of this invention are as follows: Firstly, the integrated cleaning module in the temporary storage cavity can clean non-product wafers in situ, avoiding the time-consuming, particulate contamination, and equipment occupation problems caused by sending non-product wafers out for cleaning, and ensuring that non-product wafers are always in a clean state. Secondly, clean non-product wafers can be flexibly provided to fill the gaps according to the number of product wafers, so that the total number of wafers (product wafers and non-product wafers) entering the subsequent process in each batch remains the same. Production can be started without waiting for a full batch of product wafers, effectively improving the utilization rate of vertical furnace equipment. Thirdly, it eliminates the need for frequent adjustments to process parameters due to filling gaps, reducing the risk of process fluctuations and the workload of personnel, and enabling stable, efficient, and high-cleanliness batch production. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the wafer temporary storage device in some embodiments of the present invention; Figure 2 This is a schematic diagram of the structure of the wafer temporary storage device in some other embodiments of the present invention; Figure 3 This is a schematic diagram of the cleaning module in some embodiments of the present invention; Figure 4 This is a schematic diagram of the wafer transmission module in some embodiments of the present invention; Figure 5 This is a schematic diagram of the positioning mechanism and the positioning engagement mechanism in some embodiments of the present invention; Figure 6 This is a bottom view of the first positioning hole in some embodiments of the present invention; Figure 7 This is a bottom view of the second positioning hole in some embodiments of the present invention; Figure 8 This is a schematic diagram of the structure of a vertical furnace in some embodiments of the present invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art. The terms "comprising" and similar expressions used herein mean that the element or object preceding the word covers the element or object listed following the word and its equivalents, but do not exclude other elements or objects.

[0019] To address the problems existing in the prior art, the present invention provides a wafer temporary storage device for use in a vertical furnace. The vertical furnace includes a loading cavity, which is connected to both the process furnace body and the wafer temporary storage device, and is used to transfer wafers between different modules.

[0020] Reference Figure 1 and Figure 8 The wafer temporary storage device 10 includes a temporary storage cavity body 11, a wafer transfer module 12, several first temporary storage sub-modules 13, a cleaning module 14, and a gas transfer module (not shown in the figure). The temporary storage cavity body 11 forms a temporary storage cavity. The wafer transfer module 12 is disposed on the temporary storage cavity body 11 and is used to switch the transmission path between the temporary storage cavity and the loading cavity to a connected state or a blocked state. The first temporary storage sub-modules 13 are disposed within the temporary storage cavity and are used to store product wafers. The cleaning module 14 is disposed within the temporary storage cavity and is used to clean non-product wafers and provide cleaned non-product wafers according to the number of product wafers, so that the total number of product wafers and non-product wafers in each batch undergoing subsequent processes (such as oxidation or deposition processes) is a preset value. This preset value is determined by the process and / or the maximum carrying capacity of the wafer boat. For the same process, this preset value is usually fixed, meaning the number of wafers (the sum of product wafers and non-product wafers) fed into the furnace for processing each time is the same, in order to minimize the adverse effects of factors such as load effects and improve product uniformity. For example, if the preset value is 150, and the number of product wafers in the first batch is 125, then 25 cleaned non-product wafers need to be provided, so that the total number of wafers for subsequent processes is 150; if the number of product wafers in the second batch is 145, then 5 cleaned non-product wafers need to be provided, so that the total number of wafers for subsequent processes is 150. The gas transmission module is connected to the cleaning module 14 and is used to deliver cleaning gas into the cleaning module 14. After the non-product wafers on the same wafer boat enter the furnace for processing along with the product wafers, a film layer will grow on their surface and / or they will carry particulate impurities. After the crystal boat is removed from the furnace, the product wafers are transferred to the outside of the equipment, while the non-product wafers are transferred to the cleaning module 14 for cleaning to remove the film layer and particulate impurities grown on the surface of the non-product wafers, so that the non-product wafers are restored to a clean state that meets the process requirements. Then, as needed, they are used to fill the empty space on the crystal boat and enter the furnace for process processing. After that, they are sent to the cleaning module 14 again for cleaning. This process is repeated many times, and the non-product wafers are recycled multiple times inside the equipment.

[0021] In this application, an integrated cleaning module within the temporary storage chamber can clean non-product wafers in situ, avoiding the time-consuming, particulate contamination, and equipment occupation issues associated with external cleaning of non-product wafers, ensuring that non-product wafers remain in a clean state. It also significantly shortens the turnaround path for non-product wafers, helping to reduce the risk of breakage and lower production costs. Furthermore, it can flexibly provide the required number of clean non-product wafers to fill vacancies based on the number of product wafers, ensuring that the total number of wafers entering subsequent processes in each batch (the sum of product and non-product wafers) remains consistent. Production can begin immediately without waiting for a full batch of product wafers, effectively improving the utilization rate of the vertical furnace. It also eliminates the need for frequent adjustments to process parameters due to filling vacancies, reducing process fluctuation risks and personnel workload, and achieving stable, efficient, and high-cleanliness batch production.

[0022] The product wafer is a wafer used to fabricate process devices. The non-product wafer is not used to fabricate process devices but is primarily used to stabilize the process and improve process yield. For example, it can be a dummy wafer with no surface pattern, a monitor wafer used for process monitoring, or a pattern wafer, among other types. In one example, the non-product wafer is preferably a patterned wafer whose material and structure are adapted to the product wafer, which helps to further reduce loading effects and improve process yield.

[0023] In one example, refer to Figure 2The wafer temporary storage device further includes at least one second temporary storage submodule 16, which is disposed within the temporary storage cavity and is used to store non-product wafers, such as non-product wafers that have undergone cleaning or processing. Both the first temporary storage submodule 13 and the second temporary storage submodule 16 include a sub-temporary storage cavity body and a sub-temporary storage cavity isolation door. The sub-temporary storage cavity body has a wafer access port, and the sub-temporary storage cavity isolation door is disposed on the wafer access port. There can be more than one second temporary storage submodule 16 to store different types (e.g., different materials / sizes / patterns / thicknesses) of non-product wafers, meeting different process requirements. By setting at least one second temporary storage submodule 16 within the temporary storage cavity, product wafers and non-product wafers can be stored independently in separate areas, avoiding cross-contamination caused by mixing product wafers and non-product wafers, meeting the requirements for classified storage of different types of wafers, and further improving equipment uptime. Meanwhile, a non-product wafer temporary storage submodule is set up so that after cleaning, the non-product wafers, except for those needed to fill the next process (i.e., ideally, the non-product wafers needed for the next process are left in the cleaning chamber instead of being transferred to the non-product wafer temporary storage module to reduce the number of wafer transfers), are stored in this area (the number of non-product wafers needed for each batch is not the same), and do not need to be kept in the cleaning module. This can effectively reduce the loss of non-product wafers caused by repeated cleaning, help extend the service life of non-product wafers, and reduce customer costs.

[0024] In a preferred example, both the first temporary storage submodule 13 and the second temporary storage submodule 16 include a pod and a wafer storage cassette located inside the pod. The wafer is placed inside the wafer storage cassette. Each submodule can be fixed to the corresponding position in the temporary storage cavity in a suitable manner, such as by being supported and fixed by a relevant support structure.

[0025] The cleaning module can transfer wafers to the wafer carrier in the loading cavity using any suitable structure, such as via a wafer transfer module. However, this structure requires an additional robotic arm for transferring wafers between the cleaning module and the wafer transfer module, making it relatively complex. Therefore, in a preferred embodiment, the cleaning module includes a cleaning cavity, a cleaning cavity isolation door, and a cleaning cavity opening mechanism. The cleaning cavity has a cleaning cavity transfer port that is directly connected to the loading cavity. The cleaning cavity isolation door is located on the cleaning cavity transfer port. The cleaning cavity opening mechanism is located on the outer wall of the cleaning cavity and connected to the cleaning cavity isolation door, used to open or close the cleaning cavity isolation door, i.e., to move the cleaning cavity isolation door out of and into the cleaning cavity transfer port. With this structural design, wafers can be transferred directly between the cleaning module and the wafer carrier in the loading cavity, greatly simplifying the equipment structure. Provided that the travel range of the robotic arm can cover the area, the transfer ports of the cleaning chamber and the transfer ports of the product wafers can be spaced apart in the same horizontal direction or in the vertical direction, for example, spaced apart horizontally or vertically on the cavity wall of the temporary storage chamber body mentioned below, without any specific restrictions.

[0026] In one example, the temporary storage chamber body and the loading chamber are isolated from each other by a wall (such as the cavity wall of the temporary storage chamber body itself), on which a non-product wafer transfer port is formed. The cleaning chamber body is fixedly disposed on the inner wall of the temporary storage chamber, and the cleaning chamber transfer port is connected to the non-product wafer transfer port. In some examples, the size of the interface is larger than the cleaning chamber transfer port to provide space for the cleaning chamber isolation door to move when the cleaning chamber opening mechanism opens the cleaning chamber isolation door. Preferably, the cleaning chamber body is partially embedded in the cavity wall of the temporary storage chamber body itself, so that the non-product wafer transfer port and the cleaning chamber transfer port completely overlap. When the cleaning chamber opening mechanism opens the cleaning chamber isolation door, the cleaning chamber isolation door moves into the loading chamber without occupying the internal space of the non-product wafer transfer port.

[0027] In a specific example, both the temporary storage chamber isolation door and the cleaning chamber isolation door can adopt the openable and closable sealing structure commonly used in semiconductor device cavities, such as the slit valve door structure, without any specific restrictions.

[0028] The cleaning module is preferably a single unit to simplify the equipment structure, and preferably capable of simultaneously cleaning multiple non-product wafers to adapt to the batch processing requirements of vertical furnace equipment. In one example, refer to... Figure 3The cleaning module further includes N carrier plates 142, which are sequentially arranged on the inner wall of the cleaning chamber 141 along a direction perpendicular to the horizontal plane, where N is a natural number greater than or equal to 1. Preferably, N is the number of wafers in a batch, such as 25 wafers. The carrier plate 142 is, for example, an annular structure with an opening for a robotic arm to move in or out for wafer transfer.

[0029] In one example, refer to Figure 3 The gas transmission module includes a main pipe 143, N secondary pipes 144, N flow valves 145, and N gas spray heads 146. One gas spray head 146 is located at the top center of the cleaning chamber 141. The remaining N-1 gas spray heads 146 correspond one-to-one with N-1 support plates 142 from top to bottom and are located below the middle area of ​​the corresponding support plate 142. One end of each of the N secondary pipes 144 is connected to one of the N gas spray heads 146, and the other end of each of the N secondary pipes 144 is connected to one end of the main pipe 143. The other end of the main pipe 143 is used to connect to a cleaning gas supply unit (not shown in the figure). Each flow valve 145 corresponds one-to-one with a secondary pipe 144 and is located on the corresponding secondary pipe 144. The cleaning gas supply unit is used to provide etching gases such as HF vapor, a mixture of F2 and N2, ClF3, etc. (the specific type of gas depends on the process it has previously undergone), and can also be used to supply purging gases such as nitrogen.

[0030] The gas transmission module, through a main pipeline and multiple sub-pipelines, along with corresponding flow valves and gas spray heads, can evenly distribute cleaning gas to various spray positions within the cleaning chamber, achieving synchronous and stable gas supply to multiple carrier plates and non-product wafers. By placing one spray head at the top center of the cleaning chamber, and arranging the remaining spray heads corresponding to each carrier plate and below the center of the carrier plate, the cleaning gas can uniformly cover the wafer surface in a centrally symmetrical, top-down manner, ensuring a consistent process environment for each wafer and improving cleaning uniformity and process repeatability. Flow valves are independently configured in each sub-pipeline, allowing for individual adjustment of the gas flow rate for each path, achieving precise gas control by zone, avoiding mutual interference between gas flow rates at different workstations, and further improving process stability and processing yield.

[0031] In one example, refer to Figure 3The cleaning chamber 141 has an exhaust port 147 on its lower side wall. The gas transmission module includes an exhaust pipe 148, a pressure controller 149, and a vacuum pump 150. One end of the exhaust pipe 148 is connected to the exhaust port 147, and the other end is connected to the vacuum pump 150. The pressure controller 149 is mounted on the exhaust pipe 148 and is used to adjust the exhaust rate and the internal pressure of the cleaning chamber 141. By providing an exhaust port 147 on the lower side wall of the cleaning chamber 141 and equipping it with a negative pressure exhaust module consisting of an exhaust pipe 148, a pressure controller 149, and a vacuum pump 150, the cleaning chamber 141 can be quickly and stably evacuated to the target vacuum level, and reactive gases, impurity particles, and waste gases can be discharged from the cleaning chamber 141 in a timely manner, preventing contaminants from remaining on the wafer surface. The pressure controller 149 adjusts the exhaust rate and the internal pressure of the cleaning chamber 141 in real time, which can accurately maintain the stability of the internal pressure of the cleaning chamber 141, ensure that multiple wafers are processed in a consistent negative pressure process environment, improve the cleaning effect and process repeatability, reduce the risk of contamination in the chamber, and improve the wafer processing yield.

[0032] In another example, the cleaning module includes a cleaning chamber and a wafer carrier, the wafer carrier being erected within the cleaning chamber. In this embodiment, the wafer carrier adopts a structure similar to a process boat (i.e., a boat that carries wafers into a process furnace for processing). Specifically, the wafer carrier includes multiple spaced-apart pillars and top and / or bottom plates located at the ends of the pillars (preferably, top and bottom plates are provided at opposite ends of the pillars to improve structural stability). The pillars have multiple grooves spaced from bottom to top, and the grooves on the same horizontal plane of the multiple pillars constitute the wafer carrier positions. The number of wafer carrier positions is less than that of a process boat, and the spacing between adjacent wafer carrier positions is preferably slightly larger than the spacing between wafer carrier positions in a process boat, facilitating wafer transfer. For example, a process boat has 125 slots, while the wafer carrier in this embodiment has 25 slots.

[0033] In a further example, the wafer carrier is detachably mounted within the cleaning chamber. For instance, if the wafer carrier has a base plate, it can be placed directly within the cleaning chamber, maintaining balance under its own weight, or its stability can be enhanced by increasing the weight of the base plate. In another example, the wafer carrier can be fixed to the cleaning chamber using fasteners such as screws. Alternatively, a groove can be provided within the cleaning chamber, and the base plate of the wafer carrier can be embedded within the groove for fixation within the cleaning chamber. Other fixing methods can also be used, without strict limitations. Making the wafer carrier a detachable structure has many advantages. First, it allows for periodic disassembly and external cleaning of the wafer carrier, facilitating thorough cleaning of the cleaning chamber itself and ensuring its cleanliness. Second, it allows for selection of wafer carriers made of etching gas-resistant materials according to different process requirements, especially based on the type of etching gas, meeting more diverse process needs. Third, when needed, the wafer carrier can be removed, transforming the cleaning module into a temporary storage module for product wafers, further improving the equipment's applicability and helping to reduce equipment operating costs.

[0034] When the wafer carrier uses a boat-like structure, cleaning gas can be delivered into the cleaning chamber in various ways. For example, in some examples, a gas injection line can be installed within the cleaning chamber. This line is located on the side of the wafer carrier, connected to a gas delivery module, and extends from bottom to top. Multiple nozzles are spaced apart on the gas injection line to spray cleaning gas onto the wafers on the wafer carrier in a generally horizontal direction. In other examples, cleaning gas can also be delivered into the cleaning chamber through several air inlets located on the chamber itself. The cleaning gas gradually diffuses to the wafer surface to clean the wafer.

[0035] In one example, the inner wall of the cleaning chamber is made of a corrosion-resistant material. For example, quartz, stainless steel, or other materials with a protective coating. Using a corrosion-resistant material for the inner wall of the cleaning chamber resists corrosion from chemical gases and cleaning agents during the cleaning process, preventing chamber damage and wafer contamination by impurities, thus improving equipment durability and wafer processing yield.

[0036] In one example, refer to Figure 3 A heating plate 151 is provided on the inner wall of the cleaning chamber 141 for heating non-product wafers when needed. Specifically, the heating plate is a graphene far-infrared heating plate. The heating plate 151 on the inner wall of the cleaning chamber 141 enables uniform preheating and temperature control within the cleaning chamber 141, maintaining a stable process temperature and preventing temperature fluctuations from affecting cleaning uniformity.

[0037] In one example, the maximum number of non-product wafers that the cleaning module can clean in a single operation is an integer multiple of the maximum number of non-product wafers that a single second temporary storage submodule can store (the maximum number of non-product wafers that the cleaning module can clean in a single operation is the same as the number of carrier boards). Specifically, the maximum number of non-product wafers that the second temporary storage submodule can store is 25, and the maximum number of non-product wafers that the cleaning module can clean in a single operation is preferably 25 or 50.

[0038] It should be noted that the number of times a non-product wafer can be used is limited. For example, if a non-product wafer is damaged, has dirt that is difficult to remove, or warps excessively due to heat accumulation, affecting transmission, it should be promptly removed from the wafer storage device for disposal.

[0039] The cleaning module 14 is connected to the gas transmission module. When needed, the gas transmission module inputs cleaning gas into the cleaning module 14 to clean the non-product wafers that have undergone the process, removing impurity particles and deposited films from their surfaces. The specific type of cleaning gas depends on the process, or more specifically, on the film material on the surface of the non-product wafer. For example, the cleaning gas may include one of the etching gases such as HF vapor (to remove SiO2), F2 / N2 mixed gas (to remove SiN, etc.), or ClF3 (to remove Poly). In a preferred example, in addition to the etching gas, the cleaning gas also includes a purge gas, such as an inert gas like nitrogen or argon. After the non-product wafer is transferred to the cleaning module 14, etching gas is first introduced into the cleaning module 14 to etch the new film layer grown on the surface of the non-product wafer in the previous process. After a preset time (the preset time is, for example, determined by the previous process time and the etching rate of the etching gas), purge gas is introduced for a certain duration to remove particulate impurities and improve the cleanliness of the non-product wafer.

[0040] In a specific example, before removing the non-product wafer from the cleaning chamber, the gas transfer module delivers purge gas into the cleaning chamber to ensure that the environment within the cleaning chamber meets the transport conditions for the non-product wafer. For instance, by delivering purge gas into the cleaning chamber through the gas transfer module, residual etching gas and particulate impurities in the cleaning chamber can be minimized to achieve a clean environment similar to that inside the loading chamber. Alternatively, the gas transfer module can be used to deliver purge gas into the cleaning chamber to achieve a pressure similar to that inside the loading chamber. This significantly reduces the risk of residual etching gas and particulate impurities entering the loading chamber and causing contamination when the cleaning chamber isolation door is opened for non-product wafer transport, and also minimizes gas flow between the cleaning chamber and the loading chamber, thereby ensuring the cleanliness of the loading chamber.

[0041] In one example, refer to Figure 4 The wafer transfer module includes a transfer cavity 121 and an isolation element 122. The temporary storage cavity body and the loading cavity are isolated from each other by a wall (such as the cavity wall of the temporary storage cavity body itself). The transfer cavity 121 is a sealed cavity structure and is embedded in the wall of the temporary storage cavity body, forming a channel for transferring product wafers or non-product wafers between the transfer cavity 121 and the loading cavity.

[0042] In a specific example, refer to Figure 4 The isolator 122 is disposed within the conveying cavity 121, preferably near the loading cavity, and is used to control the connection and disconnection of the transmission path between the loading cavity and the conveying cavity 121. For example, when transferring product wafers (non-product wafers) between the loading cavity and the conveying cavity 121, the isolator 122 controls the connection of the transmission path between the loading cavity and the conveying cavity 121, and controls the disconnection of the transmission path between the loading cavity and the conveying cavity 121 after the transfer of product wafers (non-product wafers) is completed. The isolator 122 enables the loading cavity and the conveying cavity 121 to form independent environments to avoid mutual interference between the loading cavity and the conveying cavity 121 in terms of gas atmosphere, pressure, cleanliness, particulate contamination, etc., during the period of product wafer (non-product wafer) transfer.

[0043] In one example, refer to Figure 4 The positions of the first and second temporary storage submodules within the temporary storage cavity are not fixed and can be moved using appropriate structures (e.g., robotic arms). To accommodate the mobility of the first and second temporary storage submodules within the temporary storage cavity, the wafer transfer module further includes a wafer transfer docking section 123. The wafer transfer docking section 123 is located within the temporary storage cavity and connected to the transport cavity 121, serving as the docking structure between the transport cavity 121 and the first and second temporary storage submodules. Taking the transfer of a product wafer as an example, the first temporary storage submodule is moved to the wafer transfer docking section 123. After the first temporary storage submodule completes docking with the wafer transfer docking section 123, the isolation door of the sub-temporary storage cavity is opened through the wafer transfer docking section 123. After the product wafer transfer is completed, the isolation door of the sub-temporary storage cavity is closed through the wafer transfer docking section 123. Neither the first temporary storage submodule nor the second temporary storage submodule requires a separate door opening mechanism; they are opened uniformly by the transfer docking part 123, which greatly simplifies the structure. Furthermore, neither the first temporary storage submodule nor the second temporary storage submodule opens a door inside the temporary storage cavity, thus reducing the cleanliness requirements within the temporary storage cavity.

[0044] In one example, refer to Figure 1 and 2 The following describes the movement structure and implementation of the first and second temporary storage submodules within the temporary storage cavity, with reference to embodiments. The wafer temporary storage device further includes a support module and a module transfer robot 15. The support module is disposed within the temporary storage cavity and is used to support the first temporary storage submodule 13 and the second temporary storage submodule 16, and is detachably connected to both. The module transfer robot 15 is disposed within the temporary storage cavity and is used to transfer the first temporary storage submodule 13 between the support module and the wafer transfer module, and to transfer the second temporary storage submodule 16 between the support module and the wafer transfer module.

[0045] In one embodiment, the wafer transfer module is preferably a front-end integrated module system (FIMS), and the wafer transfer docking part is specifically a load port.

[0046] In one example, the main body of the sub-storage cavity, such as the bottom of a box cover, is provided with a positioning mechanism. The support module includes a support frame, several carrier platforms, and positioning and cooperating mechanisms corresponding to each carrier platform. The support frame is fixedly disposed within the storage cavity. The carrier platforms are fixedly disposed on the support frame and are used to support the first storage sub-module and the second storage sub-module. The positioning and cooperating mechanisms are disposed on the carrier platforms and cooperate with the positioning mechanism to position the first storage sub-module and the second storage sub-module to prevent the positions of the first storage sub-module and the second storage sub-module from shifting.

[0047] In one example, refer to Figure 5 The positioning mechanism includes a first positioning hole 136 and a second positioning hole 137. The positioning mating mechanism includes a first pin 138 adapted to the first positioning hole 136 and a second pin 139 adapted to the second positioning hole 137. The first pin 138 is used to insert into the first positioning hole 136, and the second pin 139 is used to insert into the second positioning hole 137 to achieve positioning mating. The number of first positioning holes 136 and second positioning holes 137 can be more than one, and their numbers can be the same or different, and their structures can be the same or different.

[0048] In one example, the structures of the first positioning hole 136 and the second positioning hole 137 are different. (Refer to...) Figure 5 , Figure 6 and Figure 7The first positioning hole 136 is composed of a cylindrical hole on the upper side and a frustum-shaped hole on the lower side, and the second positioning hole 137 is composed of an oval cylindrical hole on the upper side and an oval frustum-shaped hole on the lower side, and the long axis of the oval cylindrical hole passes through the central axis of the cylindrical hole.

[0049] In one example, both the frustum-shaped hole and the oval-shaped truncated cone hole have a guiding function, guiding the first pin and the second pin during insertion, facilitating the smooth entry of the first pin into the first positioning hole and the second pin into the second positioning hole, reducing the difficulty of docking and improving assembly efficiency; the first pin and the first positioning hole form a precision fit to achieve accurate positioning of the sub-temporary cavity body, and the second pin and the second positioning hole form a clearance fit to ensure the constraint of the positioning direction and to compensate for assembly errors, avoiding jamming, while the differentiated structure of the two facilitates quick and accurate positioning.

[0050] In one example, refer to Figure 5 The top center of the sub-temporary storage cavity body 134 is provided with a clamping engagement part 140. The clamping engagement part 140 is adapted to the clamping end of the module transfer robot for clamping by the module transfer robot to transfer the first temporary storage sub-module and the second temporary storage sub-module. Specifically, the clamping engagement part 140 includes a cylindrical structure 1401 and a protruding structure 1402. One end face of the cylindrical structure 1401 is fixedly connected to the top center of the sub-temporary storage cavity body 134. The protruding structure 1402 is disposed on the other end face of the cylindrical structure 1401 and protrudes circumferentially from the side of the cylindrical structure 1401 to prevent the cylindrical structure 1401 from falling off the module transfer robot.

[0051] In one example, the isolation component includes a door frame, a transfer chamber isolation door, and a transfer chamber opening mechanism, with the door frame disposed within the delivery chamber. Preferably, it is disposed on the side closer to the loading chamber. The transfer chamber isolation door is disposed within the door frame, and the transfer chamber opening mechanism is disposed on the door frame and connected to the transfer chamber isolation door, for opening or closing the transfer chamber isolation door, i.e., moving the transfer chamber isolation door out of or into the door frame. The transfer chamber isolation door may adopt the same structure as the cleaning chamber isolation door, such as a slit valve door structure commonly used in semiconductor equipment cavities, or other openable and sealing structures, without specific limitations.

[0052] In one example, the loading cavity is a sealed cavity structure. A loading cavity vacuum pump (not shown) is connected to the outside of the loading cavity. The loading cavity vacuum pump evacuates the air inside the loading cavity, creating and maintaining the required pressure inside the loading cavity, while also meeting the subsequent vacuum requirements of the furnace body. A vacuum breaking valve (not shown) is provided on the cavity wall of the loading cavity, which can restore the internal pressure of the loading cavity to atmospheric pressure when needed.

[0053] In another embodiment, a vertical furnace is also provided, see reference. Figure 8 The vertical furnace includes a loading cavity 20, a furnace body 30, and a wafer temporary storage device 10 as described in any of the above embodiments. Both the furnace body 30 and the wafer temporary storage device 10 are connected to the loading cavity 20. A loading cavity robotic arm is provided within the loading cavity 20. This robotic arm is used to transfer product wafers and non-product wafers to a wafer boat 201. The wafer boat 201 is then transferred to the furnace body 30 for processing. After the wafer boat 201 descends from the furnace body 30, the processed product wafers and non-product wafers are removed from the wafer boat 201. Specifically, the furnace body 30 is fixedly positioned above the loading cavity 20.

[0054] In one example, when the second temporary storage submodule is not provided in the temporary storage cavity, product wafers are transferred between the first temporary storage submodule and the wafer boat, and non-product wafers are transferred between the cleaning module and the wafer boat. When the second temporary storage submodule is provided in the temporary storage cavity, product wafers are transferred between the first temporary storage submodule and the wafer boat, and non-product wafers are transferred between the second temporary storage submodule and the wafer boat, between the second temporary storage submodule and the cleaning module, and between the cleaning module and the wafer boat.

[0055] In a specific example, the transfer process between the non-product wafer and the crystal boat is the same as the transfer process between the product wafer and the crystal boat from the first temporary storage submodule. The transfer process from the first temporary storage submodule to the crystal boat is largely the same as the transfer process from the crystal boat to the first temporary storage submodule, the difference being the transfer direction of the product wafer. Here, we take the transfer process from the first temporary storage submodule to the crystal boat as an example: The module transfer robot transports the first temporary storage submodule to the wafer transfer module, aligning the wafer access port with the wafer transfer docking unit. Then, the wafer transfer docking unit opens the isolation door of the sub-temporary storage cavity, and the transfer cavity opening mechanism opens the isolation door of the transfer cavity, connecting the main body of the sub-temporary storage cavity with the loading cavity. The loading cavity robot arm then transports all the product wafers in the first temporary storage submodule to the wafer boat. Then, the transfer cavity opening mechanism closes the isolation door of the transfer cavity, and the wafer transfer docking unit closes the isolation door of the sub-temporary storage cavity. Finally, the module transfer robot transports the first temporary storage submodule back to its original position within the temporary storage cavity.

[0056] In a specific example, the process of transferring non-product wafers from the self-cleaning module to the wafer boat is largely the same as the process of transferring non-product wafers from the wafer boat to the cleaning module. The difference lies in the direction of transfer of the non-product wafers and whether the gas transfer module delivers purge gas into the cleaning chamber to make the environment within the cleaning chamber meet the transfer conditions of the non-product wafers. Here, the process of transferring non-product wafers from the self-cleaning module to the wafer boat is taken as an example: The gas transfer module delivers purge gas into the cleaning chamber (no purge gas is required during the transfer of non-product wafers from the wafer carrier to the cleaning module), ensuring that the environment within the cleaning chamber meets the transfer conditions (such as cleanliness) for the non-product wafers. The cleaning chamber opening mechanism opens the cleaning chamber isolation door, and the transfer chamber opening mechanism opens the transfer chamber isolation door. The loading chamber robotic arm transfers the non-product wafers from the cleaning chamber to the wafer carrier as needed. Then, the transfer chamber opening mechanism closes the transfer chamber isolation door, and the cleaning chamber opening mechanism closes the cleaning chamber isolation door.

[0057] In a specific example, let's take the process of transferring non-product wafers from the self-cleaning module to the second temporary storage submodule as an example: The gas transfer module delivers purge gas into the cleaning module, ensuring the environment within the cleaning module meets the transport conditions for the non-product wafers. The module transfer robot then transports the second temporary storage submodule to the wafer transport module, aligning the wafer access port with the wafer transfer docking unit. Next, the wafer transfer docking unit opens the isolation door of the sub-temporary storage chamber, the transfer chamber opening mechanism opens the isolation door of the transfer chamber, and the cleaning chamber opening mechanism opens the isolation door of the cleaning chamber. The loading chamber robot then transports all the non-product wafers from the cleaning chamber to the second temporary storage submodule. The loading chamber robot then retracts into the loading chamber, and the wafer transfer docking unit closes the isolation door of the sub-temporary storage chamber, the transfer chamber opening mechanism closes the isolation door of the transfer chamber, and the cleaning chamber opening mechanism closes the isolation door of the cleaning chamber. The module transfer robot then transports the second temporary storage submodule back to its original position within the temporary storage chamber.

[0058] When the robotic arm's stroke is sufficient to cover the movement of both product and non-product wafers, in one example, non-product and product wafers are transferred via the same robotic arm, which helps reduce the number of devices and equipment space, thus lowering equipment costs. In a further example, with a non-product wafer storage module, when the number of non-product wafers cleaned in the cleaning chamber exceeds the number of non-product wafers needed for the next batch, the pre-processing wafer transfer process is preferably as follows: first, product wafers are transferred to the wafer boat, and then the required number of non-product wafers are transferred from the cleaning chamber to the wafer boat to fill the gaps, ensuring the total number of wafers on the wafer boat meets the process requirements. After the wafer boat containing the wafers is sent into the furnace for processing, the remaining non-product wafers in the cleaning chamber are transferred to the non-product wafer storage module. This effectively improves wafer transfer efficiency, increases equipment uptime, and reduces wafer transfer interference. If the number of non-product wafers already in the cleaning chamber is less than the number required by the process, all non-product wafers in the cleaning chamber are first transferred to the wafer boat, and then the shortfall is replenished from the non-product wafer temporary storage module.

[0059] In one embodiment, when a wafer boat needs to be fed into the furnace, a loading chamber vacuum pump evacuates the interior of the loading chamber to create a vacuum environment similar to that inside the furnace. Then, the furnace door is opened. After the furnace door is opened, a lifting device within the loading chamber feeds the wafer boat, containing both product wafers and non-product wafers (if present), into the furnace. When the wafer boat needs to be removed from the furnace, if the loading chamber maintains a vacuum environment similar to that inside the furnace, the furnace door is opened directly. Otherwise, the loading chamber vacuum pump first evacuates the interior of the loading chamber to create a vacuum environment similar to that inside the furnace before the furnace door is opened. After the furnace door is opened, the lifting device inside the loading chamber moves the wafer boat containing the product wafers and non-product wafers (if present) out of the furnace (i.e., lowers it to a preset position). Then, the furnace door closes, and the vacuum breaking valve restores the loading chamber to atmospheric conditions. Each time the furnace door is opened, a vacuum environment close to that inside the furnace is created inside the loading chamber. This avoids frequent vacuum breaking within the furnace, suppressing fluctuations in the process environment, stabilizing the process conditions for each batch of product wafers, and effectively reducing process differences between different batches of product wafers.

[0060] In one example, when the internal space of the loading cavity is large, for instance, it can accommodate an additional loading cavity auxiliary robotic arm, and the strokes of the loading cavity auxiliary robotic arm and the loading cavity robotic arm do not interfere with each other. The loading cavity robotic arm and the loading cavity auxiliary robotic arm simultaneously transfer product wafers and non-product wafers, respectively, which can reduce the total time for transferring product wafers and non-product wafers and greatly improve efficiency. For example, after the process in the furnace is completed, the loading cavity robotic arm transfers the product wafers on the wafer boat to the first temporary storage submodule, while the loading cavity auxiliary robotic arm transfers the non-product wafers on the wafer boat to the cleaning module. This eliminates the need for the loading cavity robotic arm to transfer non-product wafers, thus reducing the time for transferring non-product wafers.

[0061] In one example, the wafer transfer module can be configured as two modules, positioned in the same vertical or horizontal direction. Each of the two wafer transfer modules interfaces with a different first temporary storage submodule, working in conjunction with the loading cavity auxiliary robotic arm to simultaneously transfer product wafers within the two first temporary storage submodules. For example, if the current batch of product wafers contains 150 wafers, and the preset value is 150, and each first temporary storage submodule stores 25 product wafers, then six first temporary storage submodules are needed. With each wafer transfer module interfaced with three first temporary storage submodules, the efficiency of transferring product wafers can be doubled. For example, if the current batch of product wafers contains 125 wafers and the preset value is 150, and each first temporary storage submodule stores 25 product wafers and each second temporary storage submodule stores 25 non-product wafers, then it is necessary to transfer 5 product wafers from the first temporary storage submodule and transfer one non-product wafer from the second temporary storage submodule. If one wafer transfer module connects to 3 first temporary storage submodules and another wafer transfer module connects to 2 first temporary storage submodules and 1 second temporary storage submodule, the overall efficiency of transferring product wafers and non-product wafers can be doubled.

[0062] The vertical furnace in this embodiment, except for the inclusion of a separate cleaning module within the wafer storage device for cleaning non-product wafers, is otherwise structurally similar to existing vertical furnaces and will not be elaborated upon further. The vertical furnace of this invention can be used for various batch processes, but is particularly suitable for oxidation and deposition processes. Because the cleaning module is integrated within the equipment, non-product wafers can be cleaned internally, effectively improving equipment throughput and yield, and reducing equipment operating costs compared to external cleaning methods for non-product wafers.

[0063] While embodiments of the present invention have been described in detail above, it will be apparent to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations fall within the scope and spirit of the invention as set forth in the claims. Furthermore, the invention described herein may have other embodiments and can be implemented or carried out in various ways.

Claims

1. A wafer temporary storage device, applied to a vertical furnace, the vertical furnace including a loading cavity, characterized in that, The wafer temporary storage device includes: The main body of the temporary storage chamber forms an internal temporary storage chamber; A wafer transfer module is disposed on the main body of the temporary storage cavity and is used to switch the transmission path between the temporary storage cavity and the loading cavity to a connected state or a blocked state. Several first temporary storage sub-modules are disposed in the temporary storage cavity for storing product wafers; A cleaning module, disposed within the temporary storage chamber, is used to clean non-product wafers and provide cleaned non-product wafers according to the number of product wafers, so that the total number of product wafers and non-product wafers undergoing subsequent processes in each batch is a preset value; and, A gas transmission module, connected to the cleaning module, is used to deliver cleaning gas into the cleaning module.

2. The wafer temporary storage device according to claim 1, characterized in that, The cleaning module includes a cleaning chamber and N support plates. The N support plates are arranged sequentially on the inner wall of the cleaning chamber along a direction perpendicular to the horizontal plane, where N is a natural number greater than or equal to 1. The gas transmission module includes a main pipe, N secondary pipes, N flow valves, and N gas spray heads. One gas spray head is located at the top center of the cleaning chamber. The remaining N-1 gas spray heads correspond one-to-one with N-1 support plates from top to bottom and are located below the middle area of ​​the corresponding support plate. One end of each of the N secondary pipes is connected to one of the N gas spray heads, and the other end of each of the N secondary pipes is connected to one end of the main pipe. The other end of the main pipe is used to connect to the cleaning gas supply unit. Each flow valve corresponds one-to-one with a secondary pipe and is located on the corresponding secondary pipe.

3. The wafer temporary storage device according to claim 1, characterized in that, The cleaning module includes a cleaning chamber and a wafer carrier device. The wafer carrier device is erected in the cleaning chamber and includes multiple spaced columns and a top plate and / or a bottom plate located at the ends of the columns. The columns are spaced apart from bottom to top with multiple grooves. The grooves on the same horizontal plane of the multiple columns constitute the bearing position for the wafer.

4. The wafer temporary storage device according to claim 3, characterized in that, The wafer carrier is detachably mounted in the cleaning chamber.

5. The wafer temporary storage device according to any one of claims 2 to 4, characterized in that, The cleaning module also includes a cleaning chamber isolation door and a cleaning chamber opening mechanism. The cleaning chamber has a cleaning chamber transmission port, which is connected to the loading chamber. The cleaning chamber isolation door is located on the cleaning chamber transmission port. The cleaning chamber opening mechanism is located on the outer wall of the cleaning chamber and is connected to the cleaning chamber isolation door, and is used to open or close the cleaning chamber isolation door.

6. The wafer temporary storage device according to any one of claims 1 to 4, characterized in that, It also includes at least one second temporary storage submodule, which is disposed in the temporary storage cavity and is used to store non-product wafers. Both the first temporary storage submodule and the second temporary storage submodule include a sub-temporary storage cavity body and a sub-temporary storage cavity isolation door. The sub-temporary storage cavity body is provided with a wafer access port, and the sub-temporary storage cavity isolation door is disposed on the wafer access port.

7. The wafer temporary storage device according to claim 6, characterized in that, It also includes a support module and a module transfer robot. The support module is disposed in the temporary storage cavity and is used to support the first temporary storage sub-module and the second temporary storage sub-module, and is detachably connected to both of them. The module transfer robot is disposed in the temporary storage cavity and is used to transfer the first temporary storage submodule and the second temporary storage submodule between the support module and the wafer transfer module.

8. The wafer temporary storage device according to claim 7, characterized in that, The bottom of the main body of the sub-temporary storage cavity is provided with a positioning mechanism. The support module includes a support frame, a plurality of bearing platforms, and positioning and cooperating mechanisms corresponding to each bearing platform. The bearing platforms are fixedly mounted on the support frame and are used to support the first temporary storage sub-module and the second temporary storage sub-module. The positioning and cooperating mechanisms are mounted on the bearing platforms and cooperate with the positioning mechanism to position the first temporary storage sub-module and the second temporary storage sub-module, preventing the positions of the first temporary storage sub-module and the second temporary storage sub-module from shifting. And / or, The top center of the sub-temporary storage cavity body is provided with a clamping engagement part, which is adapted to the clamping end of the module transfer robot for clamping by the module transfer robot to transfer the first temporary storage sub-module and the second temporary storage sub-module.

9. The wafer temporary storage device according to any one of claims 1 to 4, characterized in that, The cleaning gas includes etching gas and purging gas; When the cleaning module cleans the non-product wafer, the gas delivery module supplies the etching gas to the cleaning module at least once. Before the non-product wafer is removed from the cleaning module, the gas transfer module supplies the purging gas to the cleaning module so that the environment inside the cleaning module meets the transfer conditions of the non-product wafer.

10. A vertical furnace, characterized in that, The device includes a furnace body, a loading cavity, and a wafer temporary storage device as described in any one of claims 1 to 9. Both the furnace body and the wafer temporary storage device are connected to the loading cavity. The loading cavity is equipped with a loading cavity robotic arm for transferring product wafers and non-product wafers to a wafer boat for feeding into the furnace body for processing.

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