Why do changes in wafer equipment exhaust air affect the airflow in nearby FFU areas?
What is the relationship between exhaust air changes and FFU airflow?
In semiconductor cleanrooms, wafer equipment is often equipped with a process exhaust system to remove heat, chemical gases and particles generated inside the equipment. The exhaust air volume will change according to the process status. For example, the exhaust air volume will be larger when the equipment is running, and it will decrease when the equipment is in standby or maintenance.
This change in exhaust air volume changes the air supply and flow paths around the equipment. When the exhaust air volume increases, more air is required to be supplemented near the equipment. If the air supplement path is not smooth, air may be extracted from adjacent areas, affecting the air supply coverage of nearby FFUs. When the exhaust air volume decreases, the air originally carried away by the exhaust air may change direction, causing local airflow stagnation or backflow.
Although FFU is installed on the ceiling, it is not an independent system. The FFU's supply air, room return air, process exhaust air and supplementary air together constitute the clean room air flow organization. Changes in any one area may affect other areas. Aili Industrial has complete production capabilities in semiconductor FFU matching and can provide FFU configuration solutions according to project air flow organization requirements. For the basic structure of the FFU machine, you can refer toAili Industrial FFU fan filter unit。
Through which paths does the change in exhaust air affect the FFU area?
Exhaust air changes affect the FFU area, usually through several paths. The first is the wind supply path. When the equipment exhaust air increases, more air is needed to supplement. If the fresh air or supplemental air does not keep up in time, negative pressure may form near the equipment, drawing air from adjacent areas and changing the FFU air supply direction.
The second is the return air path. Changes in exhaust air volume will affect the room return air volume. If the return air path is blocked by equipment or materials, poor airflow may occur in local areas, affecting the FFU air supply circulation.
The third item is the pressure difference change. Changes in process exhaust volume can change the pressure differential in a room or area. If the pressure difference fluctuates greatly, it may affect the air flow direction between the clean room and the outside, and may also affect the stability of the FFU air supply.
The fourth is a thermal plume. The heating of the equipment will generate upward airflow, which interacts with the FFU downward air supply. Changes in exhaust air volume will change the intensity and direction of the thermal plume, thereby affecting the flow field in the nearby FFU area.
How to record changes in exhaust air on site
To investigate the impact of changes in exhaust air on FFU airflow, you first need to record the exhaust status. The record content includes: equipment operating mode, exhaust air volume setting or actual measured value, exhaust air change time, wind speed and air flow direction in the FFU area before and after the exhaust air change, room pressure difference, return air status, and supplementary air status.
If the device has multiple operating modes, it is recommended to record the airflow data in each mode separately. For example, exhaust and FFU area airflow during equipment production, standby, maintenance, cleaning, etc.
These records can help determine the correlation between changes in exhaust airflow and changes in FFU airflow. If every time the exhaust air volume increases, the wind speed in the nearby FFU area decreases or the air flow direction changes, it means that there is a linkage relationship between the two.
How to check airflow paths
When checking the air flow path, you can start from the equipment exhaust vent and confirm step by step along the air flow direction. Confirm the position and volume of the exhaust outlet, confirm the direction from which the supplementary air enters the equipment area, confirm the path from which the return air leaves, and confirm whether the FFU air supply covers the key areas around the equipment.
If you find that the supply air path is not smooth, you can check the fresh air inlet, supply air valve, air supply duct and room opening. If the return air path is blocked, you can check the return air vents, return air channels and ceiling mezzanines. If the FFU air supply is affected by the exhaust air, you can evaluate whether the FFU layout position and air supply direction need to be adjusted.
For semiconductor cleanrooms, verification of airflow paths usually requires a combination of CFD simulations or on-site airflow visualization testing. Field testing can use smoke, wire, or anemometers to observe the direction of airflow.
In what directions can you start with balance adjustments?
If it is confirmed that the change in exhaust air affects the airflow in the FFU area, it can be adjusted in several directions. Optimize the air supply path to ensure that the supply air can keep up with the equipment exhaust air changes in time and reduce the extraction of adjacent areas. Adjust the return air path to prevent the return air from being blocked by equipment or materials and maintain smooth air circulation. Adjust the FFU layout or air supply direction so that critical areas can still maintain air supply coverage when the exhaust air changes. Adjust the pressure difference control strategy to reduce pressure difference fluctuations caused by changes in exhaust air.
For projects where equipment exhaust air changes significantly, you can also consider airflow separation between the equipment area and surrounding areas to reduce mutual influence. If the equipment requires local exhaust, an independent exhaust hood or enclosure can be designed.
The role of FFU in the system
FFU is mainly responsible for circulating filtration and air supply in semiconductor clean rooms. It provides clean air and maintains regional airflow organization, but cannot alone solve system problems caused by changes in exhaust air. The air supply volume, static pressure and layout of the FFU need to be coordinated with the exhaust, return air and make-up air systems.
If the project needs to adjust the FFU configuration to adapt to changes in exhaust air, you can choose FFU with different air volumes, static pressures or control methods. If the project requires group control adjustment, you can refer toFFU/EFU group control touch screen controller andFFU computer group control system understands the partition adjustment plan. Aili Industry has complete production capabilities in FFU complete machines and control systems, and can provide supporting solutions according to project air flow organization requirements.
Issues that should be confirmed in advance during project communication
During the airflow design and inspection stage of semiconductor clean rooms, it is recommended to confirm the following with the designer and equipment supplier: the exhaust volume range and variation pattern of the wafer equipment; the capacity and response speed of the supplemental air system; the return air path and the location of the return air outlet; the room pressure difference control strategy; FFU layout and air supply coverage; protection requirements for key areas; whether CFD simulation or on-site testing is required; and the adjusted verification method.
If you are dealing with the impact of wafer equipment exhaust on FFU airflow, you can visitAili Industrial FFU fan filter unit to learn about the complete machine configuration, you can also contact Aili Industrial to obtain air supply solution support for semiconductor projects.
in conclusion
Changes in the exhaust air of wafer equipment will affect the airflow in the nearby FFU area through paths such as makeup air, return air, pressure difference, and thermal plume. FFU is not an independent system. Exhaust air, return air, supplementary air and supply air need to be jointly evaluated. During the inspection, the exhaust status and air flow data should be recorded, the air flow path should be checked, and then adjustments should be made from supplementary air, return air, FFU layout and pressure difference control.
Aili Industrial has complete production capabilities in semiconductor FFU supporting and control systems, and can provide FFU configuration solutions according to project air flow organization requirements. If you need to know more about FFU applications in semiconductor clean rooms, you can visitAili Industrial FFU fan filter unit , you are also welcome to contact Aili Industrial for project support.
