Airflow control system and airflow control method

Abstract

The present invention relates to a gas flow control system and a gas flow control method, the gas flow control system comprising: a first gas supply unit which is disposed on a top plate of a chamber main body and supplies a first gas toward a stage from above the stage; a second gas supply unit which is disposed on the bottom plate of the chamber body and supplies a second gas toward the stage from below the stage; and a control part for driving the first gas supply part and the second gas supply part to supply the first gas and the second gas when the workbench ascends and descends, according to the gas flow control method, when the workbench ascends and descends, the spray head is driven to supply the first gas to the workbench, and meanwhile, the spray head is driven to supply the second gas to the workbench. A ballast gas port is driven to supply a second gas toward the table.

Description

Technical Field

[0001] This invention relates to an airflow control system and an airflow analysis method, specifically to an airflow control system and an airflow analysis method for reducing particulate contamination of wafers during the lifting and lowering of a worktable by supplying appropriate gas into the processing chamber. Background Technology

[0002] During semiconductor processing, particulate matter within the processing chamber can easily contaminate the wafer, leading to a significant decrease in final product quality and yield. To avoid this, the processing chamber is typically evacuated to remove as much of this particulate matter as possible.

[0003] While existing vacuuming operations cannot achieve a complete vacuum, they can bring the internal space of the processing chamber to the specified vacuum level required for semiconductor processing. Although this significantly reduces the total number of particles and improves particulate contamination, the risk of wafer contamination still exists when the internal space of the processing chamber is disturbed by other factors.

[0004] It is known that particulate matter has extremely small mass and, in a vacuum environment, usually remains suspended or slowly settles over time due to gravity. However, when the small amount of gas remaining in the processing chamber is disturbed, the particulate matter, which is in a stable suspended state, will be displaced, and settled particulate matter may be re-erected. Therefore, the risk of particulate matter coming into contact with the wafer and causing contamination increases significantly.

[0005] Specifically, in the processing chamber used for plasma-enhanced chemical vapor deposition (PECVD), the main body of the chamber is a sealed structure to prevent external contaminants such as particulate matter from entering. At the same time, suction ports are formed in the lower part of the bottom plate or side wall of the main body of the chamber and connected to a vacuum pump to perform a vacuuming operation on the internal space of the processing chamber, thereby timely removing contaminants such as particulate matter and ensuring that the vacuum degree in the processing chamber meets the specified requirements.

[0006] At this point, although the processing chamber has reached the specified level of cleanliness, when the worktable in the processing chamber is lifted or lowered to load or unload wafers or according to different processing steps, the pressure in various parts of the processing chamber will change and turbulence will be generated (i.e., the disturbance mentioned above). This will cause the suspended particles to shift and will also re-raise the settled particles, thereby increasing the risk of the wafer coming into contact with the particles and becoming contaminated.

[0007] To address this issue, solutions have been proposed in the field to reduce the lifting speed of the worktable to decrease turbulence. However, this slows down the processing steps, prolongs the overall processing cycle, and consequently reduces product production efficiency. Additionally, adding pumping baffles to improve the gas suction path and reduce turbulence has been suggested. However, this increases the overall hardware quantity and complexity of the semiconductor processing equipment. A more complex structure hinders equipment production, assembly, maintenance, replacement, miniaturization, and cost reduction. Furthermore, changes to the internal structure of the processing chamber may affect processing results and ultimately product quality.

[0008] On the other hand, solutions have been proposed to add new or improve existing gas filters, edge rings, slit valve covers, etc. However, these solutions also have various problems caused by changing the hardware structure as mentioned above. Moreover, these solutions are proposed from the perspective of preventing external particulate matter from entering, and are not applicable to particulate matter that already exists in the processing chamber.

[0009] Therefore, there is a need for a technical solution that can easily reduce particulate matter contamination of wafers during the lifting and lowering of the worktable without reducing the lifting and lowering speed of the worktable or changing the hardware structure of the semiconductor processing equipment. Summary of the Invention

[0010] Technical issues The purpose of this invention is to provide an airflow control system that reduces particulate matter contamination of wafers during the lifting and lowering of the worktable by supplying gas into the processing chamber.

[0011] The purpose of this invention is to provide an airflow control method that reduces particulate matter contamination of wafers during the lifting and lowering of the worktable by supplying gas into the processing chamber.

[0012] Technical solution The present invention provides an airflow control system comprising: a first air supply unit disposed on the top plate of a chamber body for supplying a first gas from above the worktable toward the worktable; a second air supply unit disposed on the bottom plate of the chamber body for supplying a second gas from below the worktable toward the worktable; and a control unit for driving the first air supply unit and the second air supply unit to supply the first gas and the second gas when the worktable is raised or lowered.

[0013] As one implementation, when the worktable descends, the control unit can drive the first gas supply unit to supply the first gas at a first flow rate; when the worktable rises, the control unit can drive the first gas supply unit to supply the first gas at a second flow rate greater than the first flow rate.

[0014] In one implementation, the first air supply unit may be a spray head.

[0015] In one embodiment, the second gas supply unit may be a ballast gas port.

[0016] In one embodiment, the first gas and the second gas may include one or more combinations of nitrogen, argon and helium.

[0017] In one implementation, the first gas and the second gas may be the same as or different from each other.

[0018] The present invention provides an airflow control method, wherein when the worktable is raised or lowered, a spray head is driven to supply purge gas toward the worktable, and at the same time, a ballast gas port is driven to supply ballast gas toward the worktable.

[0019] As one implementation, when the worktable descends, the spray head is driven to supply the purging gas at a first flow rate; when the worktable rises, the spray head is driven to supply the purging gas at a second flow rate greater than the first flow rate.

[0020] As one embodiment, the purge gas and the ballast gas may include one or more combinations of nitrogen, argon, and helium.

[0021] In one implementation, the purge gas and the ballast gas may be the same as or different from each other.

[0022] Beneficial effects The airflow control system and airflow control method of the present invention can reduce the contamination of the wafer by particulate matter during the lifting and lowering of the worktable without reducing the lifting and lowering speed of the worktable.

[0023] The airflow control system and airflow control method of the present invention can reduce the contamination of wafers by particulate matter during the lifting and lowering of the worktable without changing the hardware structure of the semiconductor processing equipment. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of an airflow control system according to one embodiment of the present invention.

[0025] Figure 2 This is a schematic diagram illustrating an airflow control system according to one embodiment of the present invention in conjunction with a processing chamber.

[0026] Figure Labels 1: Airflow control system 2: First Gas Supply Department 3: Second gas supply unit 4: Processing chamber 41: Main body of the chamber 411: Process Space 42: Workbench 43: Sprayer head 44: Suction Port 45: Ballast gas port 46: Lifting mechanism 47: Corrugated pipe Detailed Implementation

[0027] Hereinafter, an airflow control system 1 according to one embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0028] Figure 1 This is a schematic diagram of an airflow control system according to one embodiment of the present invention. Figure 2 This is a schematic diagram illustrating an airflow control system according to one embodiment of the present invention in conjunction with a processing chamber.

[0029] like Figure 1 As shown, the airflow control system 1 of the present invention may include a first air supply unit 2, a second air supply unit 3, and a control unit (not shown). The first air supply unit 2 is disposed above the second air supply unit 3 and is used to supply a first gas from top to bottom. The second air supply unit 3 is disposed below the first air supply unit 2 and is used to supply a second gas from bottom to top. The control unit is used to drive the first air supply unit 2 and the second air supply unit 3 to supply the first gas and the second gas.

[0030] Hereinafter, an airflow control system 1 according to one embodiment of the present invention will be described in detail with reference to the processing chamber 4. The processing chamber 4 may be a processing chamber commonly used in the art for performing chemical vapor deposition (CVD) or plasma-enhanced chemical vapor deposition (PECVD), etc., and the present invention is not limited thereto.

[0031] like Figure 2As shown, the processing chamber 4 may include, for example, a chamber body 41, a worktable 42, a spray head 43, a suction port 44, and a ballast gas port 45. The chamber body 41 may be a sealed hollow structure to provide a process space 411 for performing various processing steps. The worktable 42 may be tray-shaped and disposed within the chamber body 41 to hold the wafer to be processed, and may be combined with a heater (not shown) to heat the wafer to an appropriate temperature according to different processing steps. The spray head 43 may be disposed on the top plate of the chamber body 41 for spraying process gases onto the upper surface of the wafer to process the wafer and / or spraying purge gases onto the wafer to remove excess process gases. The suction port 44 may be disposed on the bottom plate of the chamber body 41 and may be connected to an external vacuum pump for evacuating the process space 411. The ballast gas port 45 can be located at the bottom plate of the chamber body 41 and can be connected to an external ballast gas source to provide ballast gas to the process space 411. The purge gas and the ballast gas can be, for example, nitrogen, argon or helium, etc. Those skilled in the art can make appropriate selections according to actual needs, and the present invention is not limited thereto.

[0032] The worktable 42 can be a height-adjustable structure. Specifically, a lifting mechanism 46 can be provided below the worktable 42. The lifting mechanism 46 can be disposed through the bottom plate of the chamber body 41. The lower part of the lifting mechanism 46 can extend outward from the chamber body 41, and the upper part of the lifting mechanism 46 can extend into the interior of the chamber body 41 and support the bottom of the worktable 42. Further, a bellows pipe 47 can be disposed between the bottom plate of the chamber body 41 and the lower part of the lifting mechanism 46 to ensure the sealing of the processing chamber 4 during the operation of the lifting mechanism 46. In this case, the ballast gas port 45 can also be located at the lower part of the lifting mechanism 46 to provide ballast gas to the process space 411 through the bellows pipe 47, instead of having a separate opening on the chamber body 41.

[0033] When wafers need to be loaded or unloaded on the worktable 42, the worktable 42 lowers to provide sufficient space above it for easy loading, unloading, and loading / unloading of wafers. When processing steps are required on the wafers it carries, the worktable 42 rises to approach the spray head 43, so that the upper surface of the wafers carried is in full contact with the process gases from the spray head 43 and / or to ensure the purging effect of the purging gases on the wafers.

[0034] During the lifting operation of the worktable 42 as described above, although the total number of particles in the process space 411 does not increase, the risk of the wafer coming into contact with particles increases.

[0035] Specifically, when the worktable 42 rises, the pressure above the worktable 42 increases, causing particles to accumulate above the worktable 42. That is, the density of particles increases, increasing the risk of the wafer being carried coming into contact with particles. At the same time, the pressure below the worktable 42 decreases, making it easier to lift and sink particles, causing more particles to be suspended in the process space 411, which also increases the risk of the wafer coming into contact with particles.

[0036] When the worktable 42 descends, the pressure below the worktable 42 increases and the pressure above the worktable 42 decreases, causing some particles below the worktable 42 to move to the top of the worktable 42 via the side of the worktable 42. This results in an increase in the number of particles located above the worktable 42, thereby increasing the risk of the wafer coming into contact with particles.

[0037] In addition, changes in pressure above and below the worktable 42 can cause turbulence to form in the process space 411, causing the originally stable suspended particles to oscillate, thereby increasing the risk of the wafer coming into contact with the particles.

[0038] Since the process space 411 has already reached a specified vacuum level, it is difficult to further eliminate the influence of these particulate matter through vacuuming. To solve this problem, the airflow control system 1 of the present invention reduces the contamination of the wafer by particulate matter during the lifting and lowering of the worktable 42 by forming an airflow within the chamber body 41.

[0039] Specifically, the first gas supply unit 2 can be disposed on the top plate of the chamber body 41, for supplying a first gas from above the worktable 42 toward the worktable 42. The second gas supply unit 3 can be disposed on the bottom plate of the chamber body 41, for supplying a second gas from below the worktable 42 toward the worktable 42. The control unit can drive the first gas supply unit 2 and the second gas supply unit 3 to supply the first gas and the second gas when the worktable 42 is raised or lowered.

[0040] Since the vacuuming operation in the processing chamber 4 is continuous, during this process, by supplying the first gas, a first airflow can be formed from the first gas supply unit 2 to the suction port 44. This first airflow can carry particles located above the worktable 42 and discharge them outside the process space 411. Simultaneously, by supplying the second gas, a second airflow can be formed from the second gas supply unit 3 to the suction port 44. This second airflow can carry particles located below the worktable 42 and discharge them outside the process space 411.

[0041] Therefore, without reducing the lifting speed of the worktable 42, the contamination of the wafer by particulate matter during the lifting process of the worktable 42 can be reduced. Thus, the processing speed of each step is not slowed down, the overall processing cycle is not prolonged, and the production efficiency is not reduced. On the contrary, the product quality and yield can be further improved.

[0042] Preferably, the airflow control system 1 of the present invention can adjust the supply flow rate of the first gas according to whether the worktable 42 rises or falls. Specifically, when the worktable 42 falls, the control unit can drive the first gas supply unit 2 to supply the first gas at a first flow rate; when the worktable 42 rises, the control unit can drive the first gas supply unit 2 to supply the first gas at a second flow rate greater than the first flow rate. That is, when the worktable 42 rises, increasing the risk of the wafer it carries directly contacting particulate matter, the control unit drives the first gas supply unit 2 to supply the first gas at a relatively large supply flow rate to improve the removal performance of particulate matter. When the worktable 42 falls, relatively reducing the risk of the wafer it carries directly contacting particulate matter, the control unit drives the first gas supply unit 2 to supply the first gas at a relatively small supply flow rate to avoid waste.

[0043] Correspondingly, the airflow control system 1 of the present invention can also adjust the supply flow rate of the second gas according to whether the worktable 42 rises or falls. However, the particles that the second gas is intended to remove, i.e., particles located below the worktable 42, will not directly contact the wafer. Even if these particles move above the worktable 42, they will be removed by the first gas. Therefore, the supply flow rate of the second gas only needs to be sufficient to balance the pressure difference between the top and bottom of the worktable 42, suppress the rising of sinking particles, and effectively remove particles below the worktable 42.

[0044] The supply flow rates of the first gas and the second gas can be monitored and controlled using a mass flow controller (MFC) commonly used in the art, and this invention is not limited thereto. Furthermore, the supply flow rates of the first gas and the second gas can be selected based on the actual shape and volume of the process space 411 and the actual shape and volume of the worktable 42, as well as its position and displacement range within the process space 411, and this invention is not limited thereto.

[0045] On the other hand, the first gas and the second gas include one or more combinations of nitrogen, argon, and helium. Furthermore, the first gas and the second gas may be the same as or different from each other. Those skilled in the art can make appropriate selections according to actual needs, and the present invention is not limited thereto.

[0046] In a preferred embodiment, the first air supply unit 2 may be the spray head 43, and the second air supply unit 3 may be the ballast gas port 45.

[0047] That is, the airflow control system 1 of the present invention can directly use the original spray head 43 and ballast gas port 45 of the processing chamber 4 as the first air supply unit 2 and the second air supply unit 3, respectively. Therefore, without changing the hardware structure of the semiconductor processing equipment, it is possible to easily reduce the contamination of the wafer caused by particulate matter during the lifting and lowering of the worktable 42.

[0048] Alternatively, the control unit can be the original control unit in the processing chamber 4 used to control various processing steps. Only by making appropriate modifications to its original control program can the control operation of the control unit be executed.

[0049] At this time, when the worktable 42 is raised or lowered, the control unit drives the spray head 43 to spray the purging gas, and simultaneously drives the ballast gas port 45 to spray the ballast gas. Preferably, when the worktable 42 is lowered, the control unit drives the spray head 43 to supply the purging gas at a first flow rate, and when the worktable 42 is raised, the control unit drives the spray head 43 to supply the purging gas at a second flow rate greater than the first flow rate.

[0050] The airflow control system 1 according to one embodiment of the present invention has been described in detail above. Hereinafter, an airflow control method according to one embodiment of the present invention will be described in detail, but parts identical to those in the airflow control system 1 will not be repeated.

[0051] Refer again Figure 2 According to the airflow control method of the present invention, when the workbench 42 is raised or lowered, the spray head 43 is driven to supply the purging gas toward the workbench 42, and at the same time, the ballast gas port 45 is driven to supply the ballast gas toward the workbench 42.

[0052] When the worktable 42 descends, the spray head 43 can be driven to supply the purging gas at the first flow rate; when the worktable 42 rises, the spray head 43 can be driven to supply the purging gas at a second flow rate greater than the first flow rate.

[0053] The purging gas and the ballast gas may include one or more combinations of nitrogen, argon, and helium.

[0054] The purging gas and the ballast gas may be the same as or different from each other.

[0055] In summary, a detailed description of an airflow control system 1 and an airflow control method according to one embodiment of the present invention has been provided. However, this is only one specific embodiment of the present invention, and the present invention is not limited thereto. The scope of the present invention is defined only by the appended claims, and their equivalents also fall within the scope of the claims.

Claims

1. An airflow control system, characterized in that, include: The first gas supply unit is located on the top plate of the main body of the chamber and is used to supply the first gas from above the worktable toward the worktable. A second gas supply unit, disposed on the bottom plate of the chamber body, is used to supply a second gas from below the worktable toward the worktable; and The control unit drives the first gas supply unit and the second gas supply unit to supply the first gas and the second gas when the worktable is raised or lowered.

2. The airflow control system according to claim 1, characterized in that, When the worktable descends, the control unit drives the first gas supply unit to supply the first gas at a first flow rate. When the worktable rises, the control unit drives the first gas supply unit to supply the first gas at a second flow rate greater than the first flow rate.

3. The airflow control system according to claim 1, characterized in that, The first air supply unit is a spray head.

4. The airflow control system according to claim 1, characterized in that, The second gas supply unit is the ballast gas port.

5. The airflow control system according to claim 1, characterized in that, The first gas and the second gas include one or more combinations of nitrogen, argon and helium.

6. The airflow control system according to claim 1, characterized in that, The first gas and the second gas may be the same as or different from each other.

7. An airflow control method, characterized in that, When the worktable is raised or lowered The driving spray head supplies purging gas toward the worktable, and at the same time, the driving ballast gas port supplies ballast gas toward the worktable.

8. The airflow control method according to claim 7, characterized in that, When the worktable descends, the spray head is driven to supply the purging gas at a first flow rate. When the worktable rises, the spray head is driven to supply the purging gas at a second flow rate greater than the first flow rate.

9. The airflow control method according to claim 7, characterized in that, The purging gas and the ballast gas include one or more combinations of nitrogen, argon, and helium.

10. The airflow control method according to claim 7, characterized in that, The purging gas and the ballast gas may be the same as or different from each other.

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