Wafer processing system and method based on stacked load lock

Abstract

The application relates to a wafer processing system and method based on a stacked load lock. The system comprises a load lock module, a wafer conveying module, a process module and a gas path control module. One side of the load lock module is connected with the process module through a vacuum transmission cavity, the other side is connected with an atmospheric environment, and the load lock module adopts a double-layer load lock structure. Each layer is provided with a wafer boat on the left side and the right side, each wafer boat adopts a five-slot design, and five wafers are carried in parallel. The wafer conveying module comprises a wafer box, a front-end module and a robot. The process module comprises two process cavities, which are used for executing preset process treatment on wafers. The gas path control module is built in the load lock module and is used for vacuum pumping and vacuum breaking operation, so as to control the gas environment in the load lock. Compared with the prior art, the application has the advantages of improving the throughput and improving the overall system efficiency.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, and in particular to a wafer processing system and method based on stacked load lock. Background Technology

[0002] In the semiconductor manufacturing industry, load lock (LL) is used to transfer wafers between vacuum and atmospheric environments, ensuring a vacuum environment in the process chamber while improving equipment production efficiency. With the continuous advancement of semiconductor processes, medium- and high-temperature processes (such as chemical vapor deposition and resist stripping) have become indispensable. In these processes, the substrate wafer typically experiences temperatures of 200-600°C or higher. After the process is complete, it needs to be cooled before being released into the atmospheric environment to avoid problems such as thermal shock, oxidation, material deformation, and surface contamination. However, existing load lock designs often struggle to balance high throughput (high WPH) and efficient cooling capabilities. This is particularly problematic in fast processing techniques, such as resist stripping, or applications requiring rapid wafer heating and cooling (preheating or cooling), such as CVD (Chemical Vapor Deposition), ALD (Atomic Layer Deposition), and ALE (Atomic Layer Etching).

[0003] Existing wafer cooling methods and their limitations:

[0004] 1. Existing cooling chamber designs in transfer chambers: Some semiconductor devices integrate cooling chambers within the transfer chamber (TC) to complete the cooling process in a vacuum environment. While this method reduces the risk of oxidation from wafer exposure to the atmosphere, it occupies space that could be used for the reaction chamber, impacting overall throughput. Therefore, this method is not the preferred solution for most high-throughput devices.

[0005] 2. The existing EFEM (Equipment Front End Module) cooling cavity design involves creating a cooling cavity within the front-end module capable of housing multiple wafers. However, this approach has the following problems:

[0006] First, it requires a wafer loading and unloading machine, which increases the horizontal size of the equipment and reduces the overall space utilization rate.

[0007] Second, high-temperature wafers are exposed to the atmosphere during transport within the EFEM, which can easily lead to excessive oxidation or adverse reactions, affecting wafer quality.

[0008] Therefore, the application of this method is very limited, especially in high-precision manufacturing processes, where it is often used as an alternative or to further ensure the lower limit of cooling.

[0009] From the perspective of the structural design of the load lock itself, existing technologies include batch load lock and high-throughput single-wafer load lock systems.

[0010] Batch load cells typically load 50 wafers at a time (one on each side, totaling 50). In this system, due to the relatively long residence time of the wafers within the load cells, some wafers can naturally cool down within the load cells, thus eliminating the need for an additional cooling system. However, this batch operation method has the following drawbacks: The batch transfer efficiency for individual wafers is limited. When process times are short (such as resist removal processes), batch load cells cannot fully utilize the advantages of high-throughput equipment and may instead become a bottleneck limiting the system's WPH (Wafers Per Hour). Furthermore, the cooling time of the batch design depends on the natural waiting time within the load cells, which, in some high-temperature processes (>400°C), may still cause the last few wafers to overheat during transport.

[0011] Meanwhile, high-throughput monolithic load-lock systems also face cooling challenges. In certain specific semiconductor equipment (such as high-throughput resist stripping equipment, 4316 CVD equipment, etc.), monolithic or dual-wafer load-lock structures are used to support efficient wafer transfer. However, this design presents critical issues in high-temperature process environments:

[0012] Insufficient natural cooling time: Due to the alternating operation of the load lock, the wafer spends a short time in the load lock and cannot be cooled down naturally.

[0013] Exposed to atmospheric conditions, the wafers remain at high temperatures, potentially leading to oxidation and thermal stress, which can negatively impact product quality. While throughput has increased, cooling capacity remains insufficient to meet the requirements of high-temperature processes.

[0014] In summary, in current wafer processing systems, load locks cannot simultaneously achieve high throughput and efficient cooling, and both processing efficiency and cooling capacity need to be improved. Summary of the Invention

[0015] The purpose of this invention is to overcome the defects of the prior art and provide a wafer processing system and method based on stacked load lock.

[0016] The objective of this invention can be achieved through the following technical solutions:

[0017] According to one aspect of the present invention, a wafer processing system based on a stacked load lock is provided. The wafer processing system includes a load lock module 1, a wafer transfer module, a process module, and a gas path control module.

[0018] One side of the load lock module 1 is connected to the process module through the vacuum transmission chamber, and the other side is connected to the atmospheric environment; a first valve is provided between the load lock module 1 and the atmospheric environment, and a second valve is provided between the load lock module 1 and the vacuum transmission chamber;

[0019] The load lock module 1 is a double-layer load lock structure. When the upper load lock 11 is transferring wafers, the lower load lock 12 is vacuuming or breaking the vacuum, forming an alternating cyclic processing mode. Each load lock has a crystal boat 13 on its left and right sides. The crystal boat 13 adopts a five-slot design to realize the parallel carrying of five wafers.

[0020] The wafer transfer module includes a wafer box, a front-end module, and a robotic arm;

[0021] The process module includes two process chambers for performing preset process treatments on the wafer;

[0022] The gas path control module is built into the load lock module 1, and regulates the gas environment inside the load lock through vacuuming and vacuum breaking operations.

[0023] As a preferred technical solution, the robotic arm in the wafer transfer module includes an atmospheric transfer robotic arm and a vacuum transfer robotic arm, both of which are dual-arm robotic arms.

[0024] As a preferred technical solution, the load lock module 1 is also equipped with a wafer inspection device 14 and a bump inspection device 15. The wafer inspection device 14 is used to detect the number of wafers in the wafer boat 13. The bump inspection device 15 is equipped with a reflector to detect the bump condition of the wafer and, based on the inspection results, determine whether the wafer meets the process requirements.

[0025] As a preferred technical solution, the gas path control module includes a vacuum pumping submodule and a gas supply submodule.

[0026] As a preferred technical solution, the vacuum pumping submodule includes a vacuum pump. Each layer in the load lock module 1 is equipped with a vacuum pump, and the left and right crystal boats 13 of each layer share a vacuum pump. The vacuum pump adopts a segmented vacuuming or gas filling balance method.

[0027] As a preferred technical solution, the gas supply submodule is used to supply inert gas to the inside of the load lock, so that the gas pressure inside the load lock is restored to atmospheric pressure.

[0028] As a preferred technical solution, the wafer processing system also includes a preheating module and a cooling module 2. The preheating module is an infrared heating unit integrated into the load cavity, which is used to gradually heat the wafer during the vacuuming process so that its temperature is close to the temperature of the process cavity. The cooling module 2 includes a radiation cooling device, a cooler, and a gas control unit.

[0029] As a preferred technical solution, the cooler adopts a water-cooled cooling plate with a meandering water channel inside to uniformly remove heat, and is equipped with a water inlet 21 and a water outlet 22 to realize the circulation of cooling water; the gas control unit controls the gas supply submodule in the gas path regulation module to adjust the cavity pressure during the vacuum breaking process, so that the heat on the wafer surface is efficiently transferred to the cooling surface equipped with the cooler through the direct interaction of low-pressure gas molecules, thereby realizing the rarefaction heat exchange cooling technology to cool the wafer.

[0030] As a preferred technical solution, the wafer processing system also includes a lifting module 3; the lifting module 3 includes a lifting unit, a locking unit, and a control unit. The lifting unit is installed at the bottom of the lower load lock 12 chamber and is used to drive the entire load lock to move up and down in the vertical direction; the locking unit is used to lock the height of the load lock to ensure that the load lock remains stable and does not shake during the entire wafer picking process; the control unit is used to control the lifting unit to adjust the height of the load lock according to the wafer picking requirements of the robot and preset parameters, and to ensure that the load lock is positioned before the robot touches the wafer.

[0031] According to another aspect of the present invention, a wafer processing method based on stacked load lock is provided, the method steps including:

[0032] S1. The robotic arm removes the wafer from the wafer box and transfers it to the crystal boat 13 of the load lock module 1 via the front-end module of the equipment;

[0033] S2. Close the first valve and use the gas control module to extract gas from the inside of the load lock to make the inside of the load lock reach a vacuum state.

[0034] S3. Open the second valve, and the robotic arm takes one wafer from each of the two crystal boats 13 on the left and right, and synchronously transfers the two wafers to the two process chambers of the process module to realize the synchronous processing of the two wafers.

[0035] S4. After the wafer processing is completed in the process module, the robot arm retrieves the wafer and sends it back to the crystal boat 13 inside the load lock module 1.

[0036] S5. Close the second valve and use the gas control module to backfill inert gas into the load lock until the gas pressure inside the load lock returns to atmospheric pressure.

[0037] S6. Open the first valve and the robotic arm will send the wafer back to the wafer cassette.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] 1. In this invention, the load lock module is a double-layer load lock structure, with a crystal boat on each side of each layer. Each crystal boat employs a five-slot design to enable parallel handling of five wafers. By adopting an alternating cyclic working mode of the double-layer load lock, the lower layer simultaneously performs vacuuming or devastating while the upper layer transfers wafers, significantly shortening the waiting time for environment switching and improving the overall system processing efficiency. The five-slot crystal boat enables parallel handling of multiple wafers, and combined with the configuration of two process chambers, lays the hardware foundation for subsequent synchronous processing, effectively increasing the wafer processing capacity per unit time. The load lock in this invention uses a smaller batch (20 wafers) but higher frequency cyclic method, reducing the waiting time for a single wafer and increasing throughput. Combined with the alternating cyclic processing mode, near-continuous transmission can be achieved, improving the overall system efficiency.

[0040] 2. In this invention, both the atmospheric transfer robot and the vacuum transfer robot adopt a dual-arm structure, which enables the transfer of two wafers at a time. This is matched with the parallel load-bearing design of the double-layer load lock and the configuration of two process cavities, reducing the number of round trips of the robot and further improving the transfer efficiency of wafers between different modules. At the same time, it ensures the coordination of transfer actions in atmospheric and vacuum environments.

[0041] 3. In this invention, the wafer inspection device can monitor the number of wafers in the wafer boat in real time, avoiding transmission errors caused by missing or extra wafers; the bump inspection device accurately detects the bump status through a reflector and determines whether it meets the process requirements, which can screen out unqualified products before the wafer enters the process module, reduce invalid process processing, reduce the risk of process failure caused by wafer quality problems, and improve the overall yield.

[0042] 4. In this invention, the gas path control module is divided into a vacuum pumping submodule and a gas supply submodule, realizing independent control and coordinated operation of vacuum pumping and vacuum breaking functions. This makes the regulation of the internal gas environment of the load lock more targeted and precise, facilitating the adjustment of pumping and charging parameters according to different process requirements and enhancing the system's adaptability. Each load lock is equipped with an independent vacuum pump, which is shared by the left and right crystal boats, reducing equipment costs while ensuring vacuum pumping efficiency. The segmented vacuum pumping or gas filling balancing method can effectively slow down the rate of pressure change, avoiding the impact of sudden pressure changes on the wafer, reducing the possibility of wafer breakage or deformation due to uneven stress, and protecting the wafer's integrity. The gas supply submodule restores the load lock to atmospheric pressure by supplying inert gas. The chemical stability of the inert gas can prevent the wafer from reacting with active components in the air, preventing the wafer surface from being oxidized or contaminated, and ensuring the quality stability of the wafer after vacuum breaking.

[0043] 5. In this invention, the preheating module gradually heats the wafer during the vacuuming process, bringing its temperature close to that of the process chamber, reducing temperature fluctuations after the wafer enters the process chamber and ensuring the stability of process parameters; the multi-configuration of the cooling module provides an effective cooling path for the wafer, which can quickly cool the high-temperature wafer after the process to a suitable temperature, facilitating subsequent transfer and processing and improving the continuity of the process.

[0044] 6. In this invention, the meandering water channel design of the water-cooled cooling plate in the cooling module can uniformly remove heat and improve cooling efficiency; by adjusting the cavity pressure through the gas control unit, low-pressure gas molecules are used to achieve rarefied heat exchange cooling, which has stronger cooling capacity and significantly improves cooling efficiency compared with the traditional double-layer load lock. The residence time of the wafer in the load lock is increased, which ensures that the wafer is cooled before being exposed to the atmosphere, even under high-temperature process conditions.

[0045] 7. In this invention, the lifting unit of the lifting module can adjust the height of the load lock according to the requirements of the robot arm for wafer retrieval. The locking unit ensures that the load lock is stable and does not shake during the wafer retrieval process, and the control unit ensures that the positioning is completed before the robot arm contacts the wafer. The three work together to make the load lock more compatible and adaptable to robots with different Z-axis travel ranges, thereby improving the equipment's versatility. This also improves the wafer retrieval accuracy. The lifting structure optimizes the wafer retrieval angle and position, making the robot arm's wafer retrieval more stable and reducing misoperation. At the same time, it optimizes the throughput, reduces the time required for the robot arm's Z-axis movement, and improves the overall wafer processing speed. Attached Figure Description

[0046] Figure 1 This is a cross-sectional view of the cavity of the load lock system in this invention;

[0047] Figure 2 This is a bottom view of the load lock system in this invention;

[0048] Figure 3 This is a side view of the load lock system in this invention;

[0049] Figure 4 This is a schematic diagram of the load lock chamber layout in the embodiment;

[0050] Figure 5 The cooling profile of the wafer in this embodiment is shown.

[0051] Figure 6a This is a schematic diagram of the streamline inside the load lock cavity in the embodiment;

[0052] Figure 6b This is a vector diagram showing the velocity within the load lock cavity in the embodiment;

[0053] Figure 7a This is a pressure analysis diagram of the upper surface of the wafer inside the load lock cavity in the embodiment;

[0054] Figure 7b This is a pressure analysis diagram of the lower surface of the wafer inside the load lock cavity in the embodiment;

[0055] In the diagram, 1 is the load lock module, 11 is the upper load lock, 12 is the lower load lock, 13 is the crystal boat, 14 is the wafer inspection device, 15 is the bump inspection device, 2 is the cooling module, 21 is the water inlet, 22 is the drain outlet, 23 is the exhaust outlet for cooling the upper wafer, 24 is the exhaust outlet for cooling the lower wafer, and 3 is the lifting module. Detailed Implementation

[0056] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0057] A load lock is a transition chamber in semiconductor manufacturing equipment used to transfer wafers between atmospheric and high-vacuum environments. It typically consists of a robust vacuum chamber body and often has multiple sealed doors (entry and exit doors): one side connects to the wafer carrier / transfer area at the atmospheric end, and the other side connects to the transfer chamber at the vacuum end.

[0058] The atmospheric side door allows the wafer to enter the load lock from the wafer transfer unit, while the vacuum side door (usually a gate valve or slit valve) opens when connected to the vacuum transfer chamber. The chamber is connected to a vacuum evacuation submodule (such as a vacuum pump and evacuation lines) to create a vacuum inside; it also features an inert gas supply submodule, typically using high-purity nitrogen, to depressurize the chamber (restore atmospheric pressure) and control airflow during cooling. The chamber houses a wafer support assembly, and in this design, may also include a heat treatment module integrating a preheating heater and a cooling unit. This module contains a wafer support platform or bracket, which positions the wafer close to the heater during heating and supports it close to the cooler during cooling to optimize heat transfer. The heater typically uses a fast-response halogen lamp array to uniformly heat the wafer surface; the cooler is a water-cooled plate with internal meandering water channels to evenly remove heat, and includes an inlet 21 and an outlet 22 for circulating cooling water. In addition, the load cell is equipped with wafer transfer robots: the atmospheric side robot is responsible for transporting the wafers to be processed from the wafer cassette to the inside of the load cell, while the vacuum side robot (installed inside the transfer cavity) transports the wafers in and out of the process chamber under vacuum. To ensure cleanliness, the inner surface of the load cell is polished and strictly cleaned, and all interfaces penetrating the cavity wall (such as sensor, cable, and water pipe inlets) are vacuum-sealed.

[0059] Example 1

[0060] In this embodiment, a wafer processing system that balances high throughput (high WPH) and efficient cooling is adopted. The system employs a dual-layer load lock alternating operation, that is, when the upper load lock 11 is transferring wafers, the lower load lock 12 is evacuating or breaking the vacuum, alternating in a cycle to maximize the throughput of the device.

[0061] The specific structure of the wafer processing system is as follows: Figures 1 to 3 As shown, where, Figure 1 This is a cross-sectional view of the cavity of the load lock system; Figure 2 This is a bottom view of the load lock system; Figure 3 This is a side view of the load lock system; the load lock system includes a load lock module 1, a wafer transfer module, a process module, and a gas path control module;

[0062] One side of the load lock module 1 is connected to the process module through the vacuum transmission chamber, and the other side is connected to the atmospheric environment; a first valve is provided between the load lock module 1 and the atmospheric environment, and a second valve is provided between the load lock module 1 and the vacuum transmission chamber;

[0063] The load lock module 1 is a double-layer load lock structure. When the upper load lock 11 is transferring wafers, the lower load lock 12 is vacuuming or breaking the vacuum, forming an alternating cyclic processing mode. Each load lock has a crystal boat 13 on its left and right sides. The crystal boat 13 adopts a five-slot design to realize the parallel carrying of five wafers.

[0064] The wafer transfer module includes a wafer box, a front-end module, and a robotic arm;

[0065] The process module includes two process chambers for performing preset process treatments on the wafer;

[0066] The gas path control module is built into the load lock module 1, and regulates the gas environment inside the load lock through vacuuming and vacuum breaking operations.

[0067] This load cell employs a double-layer design with five slots on each side (top, bottom, left, and right), capable of carrying 20 wafers at a time, significantly improving transfer and cooling efficiency. The five-slot design of a single load cell facilitates the loading of 25 wafers in the most commonly used front-opening wafer fab. The double-layer design with five slots on each side is a result of considering both the wafer per inch (WPH) and the maximum travel distance of the vacuum transfer robot along the z-axis. Two layers are initially defined: five slots represent the calculated optimal number of wafers per WPH, as a full load of 25 wafers in a fab is divisible by 5. However, when the number of layers is too high, such as 10 wafers, the limited travel distance of the vacuum transfer robot along the z-axis prevents it from reaching the topmost wafer. Currently, many existing load cell designs place one or two wafers vertically per layer, while this design uses five slots to achieve a larger WPH.

[0068] The inspection of wafer bumps includes checking the positional deviation, height consistency, quantity integrity, and morphological integrity of the bumps, and determining whether the wafer meets the process requirements based on preset process thresholds.

[0069] In this embodiment, the positional deviation does not exceed ±0.05mm, the height difference is not greater than 0.03mm, the number of missing tabs is 0, and there is no damage / deformation.

[0070] This solution's load lock chamber design achieves significant breakthroughs in cooling and throughput (WPH), making it particularly suitable for wafer transfer after high-temperature processing. Specifically, it includes:

[0071] Multi-layer dual-loadlock design: Utilizing a dual-layer structure, each layer contains multiple wafer carrier components, enabling the simultaneous storage of more wafers. Each layer features five wafers on each side, totaling 20 wafers, significantly improving cooling efficiency. Compared to traditional single-wafer or dual-wafer designs, this design offers higher processing power and stronger cooling capabilities.

[0072] High-efficiency cooling mechanism: In traditional load cells, the cooling time is limited before the wafer is exposed to the atmosphere. In contrast, this solution integrates a high-efficiency gas cooling system within the load cell, enabling uniform cooling of the wafer via airflow before it enters the atmosphere. In addition to air and water cooling, the cooling system also employs the principle of rarefied heat transfer, using appropriate chamber pressure and gas flow rate to achieve a more uniform and efficient cooling process.

[0073] Synchronous vacuum pump system: The load lock chamber uses a shared vacuum pump between the left and right cavities of each layer, enabling synchronous vacuuming and breaking of the vacuum in both cavities. This reduces hardware requirements and lowers the overall system cost. Simultaneously, this design effectively improves wafer transfer efficiency and reduces waiting time.

[0074] Dual-arm vacuum transfer robot: This system is equipped with a dual-arm vacuum transfer robot that can simultaneously handle two wafers during each pick-up. This design reduces pick-up time and further improves the overall throughput (WPH) of the equipment through the efficient alternating operation of the robot arms.

[0075] Highly integrated wafer processing system: The load lock chamber design of this system not only meets the high throughput requirements of semiconductor production, but also ensures consistent wafer cooling and temperature control. Through a multi-cavity, dual-layer structure and a shared vacuum pump design, this system effectively improves wafer processing efficiency while ensuring wafer cooling performance and temperature control consistency, avoiding quality problems caused by temperature differences.

[0076] This wafer processing system is designed and optimized for wafer transport, cooling, and handling, ensuring high wafer quality while improving production efficiency. The entire wafer processing system consists of multiple modules, including a wafer boat module, a load lock chamber, an atmospheric transport module, a vacuum transport module, and a process module. The following is a detailed wafer processing flow using this system:

[0077] Loading Stage: The wafers to be processed are first loaded into the wafer transfer box: via an atmospheric transfer module, the wafers are transferred from the wafer transfer box to the load lock chamber by an atmospheric transfer robot. At this time, atmospheric pressure is maintained inside the load lock chamber to ensure smooth wafer entry and prevent contamination. Each wafer boat 13 in the load lock chamber can hold 5 wafers, with a total of 4 wafer boats 13, two wafer boats 13 per layer, forming a two-layer structure.

[0078] Vacuum Transfer Stage: After the wafer enters the load lock chamber, the EFEM-side (equipment front-end module side) valve closes, and the space within the load lock chamber is evacuated to a vacuum state by the pumping unit. Simultaneously, the TC-side (transfer chamber side) valve remains closed to ensure a vacuum environment is maintained inside the vacuum transfer module. Once the vacuum state within the load lock chamber is established, the TC-side valve opens, and the vacuum transfer robot transfers the wafer from the load lock chamber to the process module. Whether the TC-side valve is open or closed depends on the gas pressure within the load lock at that moment.

[0079] Wafer processing stage: The process module can execute the same or different processes as needed. Within the process module, the wafer undergoes various processing steps, such as resist removal, thin film deposition, and etching. The process module is designed with two connected process chambers, enabling the processing of two wafers simultaneously. Wafer temperatures typically rise within the process module; therefore, effective cooling of the wafer is crucial during processing.

[0080] The return phase of the processed wafer: The wafer, having completed its processing, is returned to the load lock chamber by a vacuum transfer robot. At this time, the load lock chamber remains under vacuum, the TC side valve is closed, and the wafer is cooled and prepared for further transfer; that is, the gas supply unit begins to cool the processed wafer to ensure that the wafer temperature is stable and to prepare it for subsequent transfer.

[0081] Atmospheric pressure restoration stage: After the processed wafer enters the load lock chamber and is cooled, the TC side valve closes, and the gas supply unit restores it to atmospheric pressure by supplying gas to the load lock chamber.

[0082] Unloading phase: Finally, the EFEM side valve opens, and the atmospheric transfer robot transfers the cooled wafer from the load lock chamber to the wafer transfer box, completing the entire processing flow.

[0083] In summary, this solution has the following advantages compared to existing technologies:

[0084] 1. Higher throughput (WPH) compared to batch load balancing:

[0085] Traditional batch-based load locks require 25 wafers to complete a transfer, and each load lock needs to process 50 wafers to complete a cycle. This solution uses a smaller batch (20 wafers) but higher frequency cycle, reducing the waiting time per wafer and increasing throughput.

[0086] By combining a two-layer alternating operation mechanism, near-continuous transmission can be achieved, improving the overall system efficiency.

[0087] 2. Vacuum system optimization design

[0088] The load lock design of this scheme allows each layer's left and right wafer boats 13 to share a single vacuum pump, meaning the entire load lock requires only two vacuum pumps to complete both vacuum pumping and vacuum breaking operations. Compared to traditional load locks that require multiple vacuum pumps to control different chambers, this scheme, through a rational vacuum zoning design, requires only two vacuum pumps to complete the entire load lock's vacuum pumping and vacuum breaking operations, saving on equipment procurement and maintenance costs. The 10 wafers on the same layer operate under identical vacuum conditions, ensuring they are under the same pressure and temperature conditions during vacuum pumping, vacuum breaking, and cooling, thereby optimizing wafer processing consistency and improving product quality.

[0089] Rare heat transfer mechanism: During the vacuum release phase of the load lock, the pressure and airflow inside the cavity are controlled to enable the wafer to be cooled more effectively during the vacuum release process.

[0090] 3. High-efficiency transmission structure:

[0091] With its dual-layer, multi-wafer load cell design, the equipment can employ a dual-arm robotic arm. During wafer retrieval from the load cell, both arms can simultaneously insert into the same layer, retrieving five wafers from each side, thus increasing retrieval speed. The robotic arm can also transport 10 wafers in batches between the load cell and the transfer chamber, handling two wafers at a time, reducing transfer time and further optimizing equipment throughput.

[0092] Example 2

[0093] In this embodiment, a wafer handling method based on stacked load locks is applied. This method optimizes vacuum pumping and devastation efficiency while ensuring efficient wafer transport and maintaining wafer processing consistency. This structure is suitable for wafer transport in and out of high-temperature processes (such as CVD, PVD, and resist removal) and significantly improves system throughput (Wafer Per Hour, WPH).

[0094] The method steps include:

[0095] S1. The atmospheric robotic arm removes the wafer from the wafer box and transfers it to the crystal boat 13 of the load lock module 1 via the front-end module of the equipment;

[0096] S2. Close the first valve and use the gas control module to extract gas from the inside of the load lock to make the inside of the load lock reach a vacuum state.

[0097] S3. Open the second valve, and the vacuum robot takes one wafer from each of the two crystal boats 13 on the left and right, and synchronously transfers the two wafers to the two process chambers of the process module to realize the synchronous processing of the two wafers.

[0098] S4. After the wafer processing is completed in the process module, the vacuum robot retrieves the wafer and sends it back to the crystal boat 13 inside the load lock module 1.

[0099] S5. Close the second valve and use the gas control module to backfill inert gas into the load lock until the gas pressure inside the load lock returns to atmospheric pressure.

[0100] S6. Open the first gate valve, and the atmospheric robotic arm will send the wafer back to the wafer box.

[0101] This method is applied to the following load lock structure: The load lock adopts a double-layer structure, with each layer containing two crystal boats 13 on the left and right. Each crystal boat 13 can carry 5 wafers, and a single layer can hold 10 wafers. The entire load lock has a total of 20 wafers, which significantly increases the number of wafers that can be processed in a single operation compared to the traditional single-layer structure of 2 to 4 wafers.

[0102] The vacuum system of the load lock is optimized: the two wafer boats 13 on the left and right sides of each layer share a single vacuum pump, meaning that only two vacuum pumps are needed to complete all vacuum pumping and devastation operations for the entire load lock. This design reduces the number of vacuum pumps, lowers equipment procurement and maintenance costs, and ensures that the 10 wafers in the same layer are under the same vacuum condition, thus optimizing wafer process consistency.

[0103] The load lock's gate valve structure includes a first gate valve and a second gate valve. The first gate valve (EFEM side atmospheric side) is used for the wafer to enter or leave the load lock and is connected to the air transfer module. The second gate valve (TC side vacuum side) is used to connect the load lock to the vacuum transfer chamber, ensuring that the wafer can enter the process module.

[0104] Vacuum Transfer System: The load lock is equipped with a dual-arm vacuum transfer robot, which can simultaneously pick up one wafer from each of the left and right wafer boats 13 on the same layer and transfer them synchronously to the process module for processing. The dual-arm robot adopts a symmetrical structure, which improves wafer picking accuracy, reduces the impact of vibration on the wafer, and optimizes the handling path, making wafer transfer more stable and reliable.

[0105] This method specifically includes the following steps:

[0106] Wafer loading:

[0107] An atmospheric transport robot removes a wafer from the wafer transport cassette and places it into the load lock. After alignment, the wafer is placed on the carrier rack, i.e., the wafer boat 13, inside the load lock, ensuring correct wafer positioning. At this point, the first valve (atmospheric side) closes, and the load lock enters a sealed state.

[0108] Vacuum the load lock:

[0109] The vacuum pump starts, extracting gas from the load lock to create a vacuum. Since the two wafer boats 13 on each layer share a single vacuum pump, the load lock can establish a vacuum environment more quickly, while ensuring that the 10 wafers on the same layer are under the same gas pressure, avoiding individual differences.

[0110] Transfer the wafer to the process module:

[0111] The second valve (vacuum side) of the load lock opens and connects to the vacuum transfer chamber. The dual-arm vacuum transfer robot picks up one wafer from each of the two crystal boats 13 on the left and right, and simultaneously transfers them to the two process chambers on the left and right, realizing the synchronous processing of the two wafers.

[0112] After processing, the wafer is returned:

[0113] After the process module completes wafer processing, the vacuum transfer robot retrieves the wafer and returns it to the load lock. The second valve (vacuum side) closes, and the load lock re-enters a sealed state.

[0114] Restoring atmospheric pressure:

[0115] The load lock is slowly backfilled with inert gas (such as nitrogen) through the gas supply submodule to prevent wafer damage caused by rapid pressure changes. Once the internal pressure of the load lock returns to atmospheric pressure, the first valve (atmospheric side) opens, and the wafer is removed by the atmospheric transfer robot and returned to the wafer transfer box.

[0116] The operation of a load lock involves a complete cycle from wafer loading to unloading, which requires strict sequential control of multiple steps.

[0117] The process for each stage is described in detail below:

[0118] 1. Wafer Loading: In an atmospheric environment, the wafer is first removed from its storage container, such as a FOUP (wafer cassette), and placed on an alignment stage by an atmospheric transfer robot via a transfer module for positioning and calibration. Once the wafer is positioned, the atmospheric side valve opens, and the robot delivers the wafer into a predetermined position inside the load lock chamber (above the support frame of the heat treatment module) through the atmospheric side inlet of the load lock. After the wafer enters, the atmospheric side door immediately closes, sealing the wafer within the load lock to await vacuum processing. The entire loading process requires smooth and accurate movements to ensure that the wafer does not shift or collide during transfer.

[0119] 2. Vacuuming Stage: Once the wafer is placed and sealed within the load cell, isolating it from the atmosphere, the system activates the vacuum pumping submodule to evacuate the cavity. Typically, a coarse pump first removes most of the gas, followed by a high-precision vacuum pump to reduce the pressure to a level close to that of the process chamber. During this process, to prevent particle agitation caused by turbulence, the vacuum control system pumps gas slowly and evenly, and may employ segmented vacuuming or gas balancing procedures to minimize the impact of sudden pressure drops on the wafer. Once the required vacuum level is reached, the interior of the load cell is essentially level with the vacuum transfer chamber. If heating is required, the heating module within the load cell activates to preheat the wafer. The heater (halogen lamp array) is turned on, heating the wafer to the required process temperature or a close temperature. Because the wafer is preheated before entering the process chamber, the subsequent heating time within the process chamber is reduced, improving overall processing efficiency. During preheating, the wafer is typically supported by a support frame at a certain distance below the heater, ensuring uniform radiant heating, while the cooler below is either off or in standby mode. Once the sensor or timing control determines that the wafer has reached the target temperature, the next step can be initiated.

[0120] 3. Wafer Transfer to Process Module: After wafer preheating and a vacuum connection established between the load lock and the transfer chamber, the valve connecting the load lock to the vacuum transfer chamber is opened. A vacuum transfer robot (vacuum arm) located within the transfer chamber extends into the load lock and precisely extracts the preheated wafer from the support assembly. This robot typically has multiple end effectors (e.g., 2 / 4 arms for parallel processing of multiple wafers), capable of horizontal rotation and vertical movement to accommodate wafer interfaces at different heights and positions. Once the robot has retrieved the wafer, the vacuum side valve closes, and the robot moves along the transfer chamber, rapidly delivering the wafer to the designated process chamber and inserting it through the appropriate vacuum gate into the process module (e.g., resist removal, CVD, PVD, or etching reaction chamber) for processing. The entire transfer process is conducted under high vacuum, preventing wafer exposure to air and contamination. Because the wafer is preheated to near the process temperature, the process chamber can start directly or reach the required temperature in a shorter time, thus completing the processing more efficiently.

[0121] 4. Wafer Return After Processing: After the processing flow (such as deposition or etching) in the process chamber is completed, the vacuum transfer robot intervenes again to remove the hot wafer from the process chamber and return it to the transfer chamber along the original path. The vacuum side valve of the load lock reopens, and the robot inserts the high-temperature processed wafer back into the load lock cavity through the transfer chamber. At this time, the wafer temperature is high and needs to be cooled rapidly for safe return to the atmospheric environment. To achieve this, the water-cooled pipes pre-fabricated in the cavity wall inside the load lock provide the basic cooling heat exchange surface, combined with air cooling and rarefaction heat transfer cooling mechanisms to maximize heat transfer. At the same time, the heater has been completely shut off and entered standby mode. The vacuum side valve closes after the robot withdraws, and the wafer remains in the closed load lock for cooling. Inside the load lock, a cooling mechanism based on the rarefaction heat transfer principle provides efficient and uniform cooling during the wafer vacuum breaking stage to control wafer thermal stress and avoid occupying additional space. Rapid cooling of the wafer begins with the help of cooling module 2. Cooling water is introduced into the cooler (through inlet 21), flowing meandering within the cooling plates to remove heat from the wafer. The heated water is then discharged from the outlet. Simultaneously, the gas supply submodule slowly introduces filtered inert gas (such as high-purity nitrogen) into the load lock, beginning to restore the chamber pressure from vacuum to atmospheric pressure. The gas filling process is precisely controlled: gas is evenly introduced into the chamber through a distributor or diffuser plate, forming a stable laminar airflow. This accelerates wafer surface cooling (gas convection removes heat) while preventing turbulent impacts that could stir up any particles within the chamber. As nitrogen is continuously introduced, the chamber pressure gradually increases; when approaching atmospheric pressure, the filling rate is typically slowed to prevent the wafer from being impacted by rapid pressure changes. Throughout the process, a clean, inert environment is maintained within the chamber, preventing direct entry of outside air that could cause moisture condensation or particulate contamination. After a certain period, the wafer temperature drops to a safe level and the chamber pressure equals external atmospheric pressure. At this point, the load lock is cooled and ready to be connected to the atmosphere.

[0122] 5. Wafer Removal: After confirming that the chamber has returned to atmospheric pressure and the wafer has cooled, the atmospheric side valve of the load lock reopens. The atmospheric side transfer robot re-enters the load lock and smoothly removes the cooled wafer from above the cooler. Finally, the atmospheric side door closes, completing the cycle processing of one wafer. At this point, the load lock is ready to receive the next wafer. If the load lock has a multi-chamber parallel structure (such as the four-chamber structure shown in this solution, with up to 2-4 inlet / outlet ports on each side, and equipped with 4 sets of heating / cooling modules2), then while one wafer is being cooled / removed from the chamber, other wafers can be preheated or transferred in parallel, thereby increasing the overall throughput. The entire removal process still strictly follows vacuum isolation and clean operation procedures to ensure that the processed wafers are not contaminated by the environment after cooling and are safely returned to the atmospheric environment.

[0123] In load lock design, airflow organization is crucial. A well-designed airflow system improves cooling efficiency while minimizing particle generation and deposition. Firstly, progressive airflow control is employed during vacuuming and depressurization: during vacuuming, the pumping speed is controlled via an adjustable throttle valve to prevent excessively rapid airflow from causing turbulence; during charging, multi-point slow charging is used, typically through a porous diffuser or rectifier plate installed inside the chamber to disperse the nitrogen entering the chamber into a uniform laminar flow. Thus, when atmospheric pressure is restored, the airflow passes smoothly vertically or unidirectionally across the wafer surface, carrying residual heat and any free particles to the exhaust ports (including exhaust port 23 for cooling the upper wafer and exhaust port 24 for cooling the lower wafer), without creating eddies within the chamber. Typically, the inlet is located at the top of the chamber or around the wafer, while the outlet (or vacuum pump) is located at the bottom. This allows the cooling airflow to flush the wafer surface from top to bottom, pushing particles downwards away from the sensitive surface and expelling them from the chamber. Before entering, the gas undergoes high-efficiency filtration (e.g., ULPA filter membrane) to ensure it is free of particles. Once inside the cavity, it forms a laminar flow, minimizing disturbance to micro-dust deposited on the cavity walls or wafer supports. Furthermore, the load lock may employ an anti-particle coating and rounded corner transitions to reduce eddies at airflow corners and facilitate the clean airflow to flush away potential particle deposition areas. By optimizing the airflow path, heat exchange efficiency is improved, allowing for faster wafer cooling, while significantly reducing the risk of intracavity particulate contamination.

[0124] Modern load locks are equipped with a highly intelligent control system that utilizes multiple sensors and automatic control algorithms to monitor and optimize operation. First, a vacuum pressure sensor is installed on the chamber to monitor internal pressure changes in real time, controlling the start / stop of the vacuum pump and valve switching: for example, the control system only allows the vacuum-side valves to open when the pressure drops to a level matching the transfer chamber; during depressurization, the atmospheric-side hatch is only unlocked when the pressure approaches atmospheric pressure and the pressure difference is safe. Second, temperature sensors are located within the heat treatment module (or near the wafer support platform) to monitor the operating status of the heaters and coolers, as well as the wafer temperature. The control system precisely adjusts the heating power or cooling water flow rate based on temperature feedback: the heater automatically shuts off when the set temperature is reached during the preheating stage; during the cooling stage, a completion signal is issued if the wafer has cooled to the target temperature. Simultaneously, gas flow monitoring is achieved through a mass flow controller (MFC) or pressure sensors, ensuring that the charging and pumping rates remain within optimized ranges to create an ideal laminar cooling airflow without introducing excessive turbulence. Some high-end systems also integrate particulate sensors or cleanliness monitoring devices. Once an abnormal increase in particle concentration is detected within the chamber, the system adjusts the evacuation / filling strategy or issues a maintenance alarm. The software of the intelligent control system coordinates the actions of each component through pre-programmed timing logic: from wafer loading, valve locking, vacuuming, and preheating timing, to door opening in conjunction with the robot, wafer transfer, cooling upon return, gradual ventilation, and finally exiting the chamber, each step has interlocking conditions to ensure safety. For example, the corresponding door will only open after the robotic arm is in position and the pressure within the chamber is balanced; heating and cooling will not operate simultaneously and are interlocked to prevent misoperation. The control system also has a recipe management function, which can set parameters such as preheating temperature, holding time, cooling curve, and vacuum / filling speed curve according to different process requirements to achieve optimized processing of different batches of wafers. Through these sensor feedbacks and automatic control, the load lock can control the transition time and temperature changes of each wafer within the optimal range while ensuring cleanliness and safety, significantly improving the operating efficiency and process controllability of the entire semiconductor equipment.

[0125] In summary, this wafer processing method achieves efficient and controllable transfer of wafers from atmospheric to vacuum and back to atmospheric. Structurally, the cavity integrates preheating and cooling modules, coupled with reliable vacuum valves, gas paths, and robotic arm interfaces. In terms of operational flow, each stage is tightly connected yet independently isolated, ensuring high-speed transfer and environmental isolation. Furthermore, optimized airflow and intelligent control maximize heat exchange efficiency and cleanliness. This processing method is compatible with the system's structural design, ensuring a seamless flow from wafer removal, transfer, processing, to return. Each step is interconnected, fully leveraging the advantages of the double-layer load lock, dual-arm robotic arm, and dual-process cavity design to achieve efficient, stable, and high-quality wafer processing, ensuring process repeatability and consistency. This entire process guarantees sufficient preheating before entering processing and rapid cooling after processing, while minimizing particulate contamination and significantly improving the throughput and yield of semiconductor manufacturing processes.

[0126] Example 3

[0127] In this embodiment, a wafer processing system based on stacked load lock is used for preheating and cooling. The wafer processing system includes a preheating module and a cooling module 2. The remaining structure is the same as described in Embodiment 1. By using this wafer processing system, the wafer is preheated before entering the process module and efficiently cooled by rarefaction heat exchange cooling technology after leaving the process module, ensuring more precise temperature management of the wafer and reducing the impact of thermal stress.

[0128] The preheating module employs a far-infrared heating unit integrated within the load lock. This unit gradually heats the wafer during the vacuuming process, bringing its temperature close to the process chamber temperature and reducing thermal shock. The preheating module can independently control the temperature of each wafer layer and adjust the heating power to ensure uniform temperature rise.

[0129] Cooling module 2 includes a radiation cooling device, a cooler, and a gas control unit. The cooler uses a water-cooled cooling plate with a meandering water channel inside to uniformly remove heat. It also has an inlet 21 and an outlet 22 to circulate the cooling water. The gas control unit regulates the chamber pressure during vacuum breaking by controlling the gas supply submodule in the gas path regulation module. This allows the heat on the wafer surface to be efficiently transferred to the cooling surface equipped with the cooler through the direct interaction of low-pressure gas molecules, thereby achieving rarefaction heat exchange cooling technology to cool the wafer.

[0130] Cooling module 2 employs rarefied heat transfer cooling technology, optimizing the chamber pressure during vacuum breaking. This allows heat from the wafer surface to be efficiently transferred to the cooling surface through the direct interaction of low-pressure gas molecules, improving cooling efficiency. Compared to traditional convection cooling, this method can cool the wafer more quickly and uniformly, and reduce the impact of thermal stress.

[0131] The specific workflow for preheating and cooling using this load lock includes:

[0132] Preheating stage: During the vacuuming process, the heating unit inside the load lock is activated to heat the wafer; when the temperature reaches the set value, the preheating ends and the wafer enters the processing state.

[0133] Wafer processing: The preheated wafers enter the process module for processing, which reduces the heating time of the process cavity and improves processing efficiency.

[0134] Cooling stage: After the wafer is processed by the process module, it is moved back into the load lock and the cooling module 2 is started. The cooling module 2 adopts the rarefaction heat exchange cooling technology, which optimizes the gap between the wafer and the cooling surface and the ambient pressure to enable rapid heat transfer and improve the cooling rate.

[0135] Restoring atmospheric pressure: After cooling, the load lock slowly backfills with inert gas to restore the internal pressure to atmospheric level, preventing cracks or deformation on the wafer surface due to temperature changes.

[0136] Calculation of heat dissipation capacity:

[0137] Description of common load-locking cavity processes:

[0138] After desmearing, the wafers are transferred from the process chamber to the load lock using a vacuum transfer robot. Once a batch is completed, the valve between the load lock and the transfer chamber is closed, and the vacuum breaking operation begins. The initial pressure inside the load lock is 45 mTorr, balanced with the pressure in the transfer chamber and the process chamber. The desmearing process temperature is 250°C.

[0139] The final pressure of the vacuum breaking operation is 1 atm, which reaches pressure balance with the chamber where the atmospheric transfer robot is located. At this time, the valve between the load lock and EFEM is opened, and the atmospheric transfer robot completes the operation of picking up the wafer from the load lock and placing it into the wafer transfer box.

[0140] Five wafers are placed in each load chamber: the wafers are sequentially removed from the process chamber and placed into the load lock by a vacuum transfer robot. The waiting times for each wafer in the load chamber are 87s, 66s, 45s, 24s, and 3s, respectively. During this period, the wafer is under vacuum with a pressure of approximately 45 mTorr, and the allowable vacuum breaking time of the load lock is 61s.

[0141] One wafer is placed in each load chamber: The wafer is removed from the process chamber by a vacuum transfer robot and placed into the load lock. The wafer waits in the load lock for 3 seconds. During this period, the wafer is under vacuum with a pressure of approximately 45 mTorr. The allowable vacuum breaking time of the load lock is 25 seconds.

[0142] The load lock condition is described as follows:

[0143] When the process involves 5 pieces per batch, the load lock chamber layout is as follows: Figure 4 As shown, the cooling curve is as follows Figure 5 As shown in the figure, the cooling curves indicate that the combination of radiation cooling and forced air cooling, combined with the vacuum breaking time of the load lock, will inevitably result in a wafer final temperature below 80°C.

[0144] When processing one wafer per batch, it takes 7 seconds for the wafer to move from the process chamber to the load lock, 3 seconds in the load lock, and then 5 seconds for vacuum breaking. This process takes a total of 15 seconds. Assuming that pure radiative cooling is performed during this time (in reality, the introduction of airflow during vacuum breaking will enhance heat dissipation), the temperature on the wafer is 198.77°C.

[0145] After 15 seconds of radiative cooling, airflow was introduced for combined radiative and forced air cooling calculations, with a cooling airflow rate of 30 LPM. In actual processes, forced air cooling lasts for 30 seconds, i.e., the calculation from... Figure 5 The radiative cooling curve begins at the 15-second mark, followed by a 30-second forced air cooling process. After 30 seconds of forced air cooling, the wafer will be cooled to approximately 100°C. At this point, the cumulative effect of rarefied heat transfer has not yet been considered. Furthermore, after the 30 seconds of forced convection, there is a 7-second robotic arm movement time between the wafer removal and its transfer to the wafer transport container. During this period, radiative cooling is used, and the final temperature on the wafer is below 90°C.

[0146] like Figure 6a The diagram shows the streamlines inside the load lock cavity. Figure 6b The diagram shows the velocity vector inside the load lock cavity; the colors change from blue to red, with the corresponding velocity values ​​gradually increasing. Blue (e.g., 0.00 m / s) represents the velocity value. -1 ()) represents a lower speed, red (e.g., 2.20 (m·s) -1 () represents a higher speed. Different colors visually represent the differences in airflow velocity distribution within the load cell, aiding in the analysis of airflow patterns. For example, it shows the varying airflow speeds in different areas, determining airflow uniformity, and assisting in understanding the hydrodynamic environment within the load cell and optimizing airflow control. For the potential wafer misalignment caused by the introduced forced air cooling, aerodynamic analysis was performed on the wafer under these conditions. The results for the ventilation conditions most likely to cause wafer misalignment, such as bottom ventilation cooling within the load cell, are as follows:

[0147] Airflow enters the load lock from the bottom distribution disk at a rate of 20 SLM (ignoring the geometry of the gas distribution disk and assuming its perfect design, resulting in completely uniform flow into the load lock). Upon entering the load lock, the airflow impacts the oncoming bottom surface of the wafer, causing a change in airflow direction, which then disperses radially along the wafer. A backflow vortex formed above the wafer causes the airflow to move downwards. Pressure analysis of the wafer's upper surface within the load lock cavity is as follows... Figure 7a As shown, the pressure analysis of the lower surface of the wafer within the load-locking cavity is as follows: Figure 7b As shown in the figure, the color scale of the pressure contour lines indicates that the pressure values ​​gradually increase from blue to red. Blue (e.g., 1.40 Pa) represents lower pressure, and red (e.g., 1.47 Pa) represents higher pressure. Different colors visually represent the pressure distribution on the upper and lower surfaces of the wafer, aiding in the analysis of pressure uniformity on the wafer surface. This helps in understanding the impact of the pressure environment on the wafer within the load lock cavity, optimizing airflow control to prevent damage to the wafer due to uneven pressure. For example, it can show pressure differences in different areas of the wafer, identifying issues such as pressure concentration. The figure shows that the overall pressure on the lower surface (windward side) of the wafer is greater than the pressure on the upper surface (leeward side). The aerodynamic force difference between the upper and lower surfaces is 0.00237 N, far less than the wafer's own weight of 1.252 N. Therefore, under these conditions (wafer and gas distribution disk 10 mm apart, airflow 20 SLM, operating pressure within the load lock 0.2 atm), the wafer will remain on the base and will not slip due to air intake at the bottom.

[0148] In summary, this solution has the following advantages compared to existing technologies:

[0149] Compared to traditional dual-layer load locks, this design offers significantly enhanced cooling capacity: Traditional dual-layer load lock designs can only accommodate one or two wafers per layer, totaling four wafers. This design, however, employs a dual-layer design with five wafers on each side, allowing for the processing of 20 wafers at a time, dramatically improving cooling efficiency. The increased residence time of the wafers within the load lock ensures that cooling is completed before exposure to the atmosphere, even under high-temperature process conditions.

[0150] Example 4

[0151] In this embodiment, a height-adjustable wafer processing system is designed to adapt to the wafer handling requirements of different vacuum transfer robots. Since vacuum transfer robots from different manufacturers have different Z-axis travel (movable height range), the wafer processing system in this solution can move up and down to optimize wafer handling and improve system compatibility. Although the travel of the vacuum transfer robot is limited, this limitation is compensated for by adding a lifting module 3 at the lower layer with a load lock. In this embodiment, the wafer processing system includes a lifting module 3 and a height adjustment control module; the remaining structure is the same as the wafer processing system in Embodiment 1.

[0152] The load lock lifting module 3 includes a lifting unit, a locking unit, and a control unit;

[0153] The lifting unit is installed at the bottom of the lower load lock chamber 12, which allows the entire load lock to be raised and lowered in the vertical direction (Z axis).

[0154] The lifting unit specifically adopts an electric lifting mechanism or a pneumatic lifting mechanism, which can achieve high-precision adjustment and ensure that the load lock and the robot arm's pick-up position are optimally matched.

[0155] The lifting unit enhances the universal compatibility with robotic arms. Different brands and models of vacuum transfer robotic arms have different ranges of motion in the Z-axis direction. This allows the load lock of this solution to be adapted to the different picking methods of robotic arms by adjusting its own height, ensuring that the picking action of the robotic arm is smooth and stable, and reducing the risk of picking up the wrong piece.

[0156] Once the load lock is adjusted to the appropriate height, the locking unit locks the height of the load lock to ensure that the load lock remains stable and does not shake during the entire wafer retrieval process.

[0157] The lifting and lowering process of the load lock is managed by the control unit. Based on the robot's wafer-picking requirements and preset system parameters, the control unit automatically controls the lifting unit to adjust the height of the load lock, precisely positioning it before the robot contacts the wafer. The control unit allows for pre-setting standard wafer-picking heights for different robots, and adjustments are completed before the robot enters the load lock area, reducing waiting time and improving overall throughput.

[0158] The specific workflow of this system is as follows:

[0159] First, wafer loading and vacuuming are performed: the load lock completes wafer loading, sealing, and vacuuming according to standard procedures.

[0160] Next, the load lock is adjusted: Before the robot arm enters the load lock, the system detects the robot arm model and retrieves its Z-axis travel parameters from the database. The lifting mechanism is activated to adjust the load lock to the optimal pick-up height for the robot arm. After the load lock is adjusted, the locking mechanism secures its position to ensure stability.

[0161] Then, the robotic arm picks up the wafer: the vacuum transfer robotic arm enters the load lock and picks up the wafer according to the set Z-axis path. Since the load lock has been adjusted to the optimal height, the robotic arm can complete the wafer pick-up with the shortest stroke, reducing the risk of wafer damage caused by Z-axis movement errors.

[0162] Finally, wafer transfer is performed: after the robotic arm removes the wafer, the lifting system of the load lock can automatically reset, waiting for the next batch of wafers to be loaded.

[0163] In summary, the liftable load lock in this embodiment has the following advantages:

[0164] Enhanced compatibility: It can adapt to robotic arms with different Z-axis travel ranges, improving the versatility of the equipment.

[0165] Improved film retrieval accuracy: The lifting structure optimizes the film retrieval angle and position, making the robotic arm more stable in film retrieval and reducing misoperation.

[0166] Throughput optimization: Reduce the time required for the robot's Z-axis movement to improve the overall wafer processing speed.

[0167] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A wafer processing system based on stacked load locks, characterized in that, The wafer processing system includes a load lock module (1), a wafer transfer module, a process module, and a gas path control module; The load lock module (1) is connected to the process module on one side through a vacuum transmission chamber and connected to the atmospheric environment on the other side; and a first valve is provided between the load lock module (1) and the atmospheric environment, and a second valve is provided between the load lock module (1) and the vacuum transmission chamber. The load lock module (1) is a double-layer load lock structure. When the upper load lock (11) performs wafer transfer, the lower load lock (12) performs vacuuming or vacuum breaking to form an alternating cycle processing mode. Each load lock has a crystal boat (13) on its left and right sides. The crystal boat (13) adopts a five-slot design to realize the parallel carrying of five wafers. The wafer transfer module includes a wafer box, a device front-end module, and a robotic arm; The process module includes two process chambers for performing preset process processing on the wafer; The gas path control module is built into the load lock module (1) and controls the internal gas environment of the load lock through vacuuming and vacuum breaking operations. The wafer processing system also includes a preheating module and a cooling module (2). The preheating module is an infrared heating unit integrated into the load cavity, which is used to gradually heat the wafer during the vacuuming process so that its temperature is close to the temperature of the process cavity. The cooling module (2) includes a radiation cooling device, a cooler and a gas control unit. The cooler uses a water-cooled cooling plate with a meandering water channel inside to uniformly remove heat, and has an inlet (21) and a drain (22) to achieve cooling water circulation; the gas control unit controls the gas supply submodule in the gas path regulation module to adjust the cavity pressure during the vacuum breaking process, so that the heat on the wafer surface is efficiently transferred to the cooling surface equipped with the cooler through the direct interaction of low-pressure gas molecules, thereby realizing the rarefaction heat exchange cooling technology to cool the wafer.

2. The wafer processing system based on stacked load lock according to claim 1, characterized in that, In the wafer transfer module, the robotic arms include an atmospheric transfer robotic arm and a vacuum transfer robotic arm, both of which are dual-arm robotic arms.

3. The wafer processing system based on stacked load lock according to claim 1, characterized in that, The load lock module (1) is also equipped with a wafer inspection device (14) and a bump inspection device (15); the wafer inspection device (14) is used to detect the number of wafers in the wafer boat (13); the bump inspection device (15) is equipped with a reflector to detect the bump condition of the wafer and, based on the detection result, determine whether the wafer meets the process requirements.

4. A wafer processing system based on a stacked load lock according to claim 1, characterized in that, The gas path control module includes a vacuum pumping submodule and a gas supply submodule.

5. A wafer processing system based on a stacked load lock according to claim 4, characterized in that, The vacuum pumping submodule includes a vacuum pump. Each layer of the load lock module (1) is equipped with a vacuum pump, and the left and right crystal boats (13) of each layer share a vacuum pump. The vacuum pump adopts a segmented vacuuming or gas filling balance method.

6. A wafer processing system based on a stacked load lock according to claim 5, characterized in that, The gas supply submodule is used to supply inert gas into the load lock, so that the internal gas pressure of the load lock is restored to atmospheric pressure.

7. A wafer processing system based on a stacked load lock according to claim 1, characterized in that, The wafer processing system further includes a lifting module (3); the lifting module (3) includes a lifting unit, a locking unit and a control unit. The lifting unit is installed at the bottom of the lower load lock (12) chamber and is used to drive the entire load lock to move up and down in the vertical direction. The locking unit is used to lock the height of the load lock to ensure that the load lock remains stable and does not shake during the entire wafer picking process. The control unit is used to control the lifting unit to adjust the height of the load lock according to the wafer picking requirements of the robot and preset parameters, and to ensure that the load lock is positioned before the robot touches the wafer.

8. A wafer processing method based on stacked load lock, characterized in that, This method operates using a wafer processing system based on a stacked load lock as described in any one of claims 1 to 6, and the method steps include: S1. The robotic arm takes the wafer out of the wafer box and transfers it to the wafer boat (13) of the load lock module (1) via the front-end module of the equipment; S2. Close the first valve and use the gas control module to extract gas from the inside of the load lock to make the inside of the load lock reach a vacuum state. S3. Open the second gate valve, and the robot arm takes one wafer from each of the two crystal boats (13) on the left and right, and synchronously transfers the two wafers to the two process cavities of the process module to realize the synchronous processing of the two wafers; S4. After the wafer processing is completed in the process module, the robot arm retrieves the wafer and sends it back to the crystal boat (13) inside the load lock module (1). S5. Close the second valve and use the gas control module to backfill inert gas into the load lock until the gas pressure inside the load lock returns to atmospheric pressure. S6. Open the first valve and the robotic arm will send the wafer back to the wafer cassette.

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