How to determine the specifications and quantity of FFU for new semiconductor projects?
Direct answer: First determine the cleanliness goals and airflow organization of each process area, and then calculate the required air supply volume and ceiling coverage area. Use the air volume, static pressure and filter resistance under project working conditions to determine the specifications of a single FFU. Calculate the quantity according to the air volume and layout area respectively. Choose a configuration that can meet both requirements at the same time. Finally, verify it through prototypes and on-site testing.
New semiconductor projects usually include process areas, equipment areas and auxiliary areas with different cleanliness requirements. The number of FFU cannot be obtained by simply dividing the room area by the area of a single unit; similarly, the product's nominal maximum air volume cannot be directly used as the design air volume. Whether the FFU can achieve the target after installation depends on the fan,Whether HEPA or ULPA filters , ceiling layout, return air paths and control methods can be matched under the same working conditions.
First determine the cleaning and air supply needs by region
Before selection, the cleanliness level, process requirements for particles, dust generation by personnel and equipment, equipment heat dissipation, operating time, and whether higher local cleanliness is required should be clarified area by area. Based on this, the design team determines the target air supply volume, work area wind speed and air flow direction in each area, and checks whether the return air is smooth.
For equipment with local high cleanliness requirements, the air supply at the equipment end and the air supply in the room should be calculated separately. The available space inside the equipment, installation interface and maintenance direction may be different from the standard ceiling FFU, and the equipment side needs to be evaluated separately.EFU fan filter unit and other solutions.
Then determine the specifications of a single FFU
First check the ceiling module or equipment installation size and screen out specifications that can be actually installed and maintained; then compare the air volume, wind speed uniformity, noise, power consumption and available static pressure of these specifications under the same test conditions . Can be obtained fromStart with FFU product specifications , but ultimately the data should be based on the filter, operating gear and system resistance conditions agreed upon in the project.
Filter efficiency should match process particle control objectives. If the project adoptsFor ULPA filters , also check its initial resistance, expected resistance changes, and the FFU's ability to maintain the target air volume after the resistance rises. The sealing between the filter and the box and the on-site replacement method should also be written into the technical requirements. Simply increasing the filtration level without rechecking the fan operating point may cause the actual air supply volume to be lower than the design value.
The quantity must be verified by air volume and layout at the same time.
After completing the selection of a single FFU, two preliminary calculations can be performed by region:
Air volume calibration: The required air supply volume of the area ÷ The effective air volume of a single FFU under the design working conditions.
Layout verification: The air supply area required to be covered by the FFU ÷ the actual air supply coverage area of a single FFU.
Both results should be rounded up, and then adjusted in combination with beam positions, lamps, sprinklers, equipment locations, maintenance channels and return air paths. If the calculated quantity meets the total air volume but leaves gaps in air supply at key process locations, it is necessary to rearrange or increase local air supply. If the ceiling can accommodate enough FFU, it is still necessary to confirm that the total air volume, airflow direction and system resistance meet the requirements.
Large-scale projects should also divide control zones according to process areas and operational needs, and confirm power supply capacity, communication interfaces, address planning and monitoring requirements in advance. When unified speed regulation or status monitoring is required, it can be evaluated simultaneously during the selection stage.FFU group control system avoids adjusting the control plan after the equipment is installed.
Confirm final configuration with prototypes and field results
The calculations and product information give the design plan, and the final quantity and specifications need to be verified. Before bulk purchasing, it is recommended to use a prototype to confirm the installation size, filter sealing, design air volume, static pressure, speed regulation and maintenance conditions; after installation, measure the wind speed and uniformity, cleanliness and actual operating status according to the technical agreement. When the test finds that the local air flow is insufficient or unevenly distributed, the FFU gear, arrangement or return air organization should be adjusted and re-verified.
When inquiring from suppliers, it is usually easier to obtain a verifiable solution than by providing only 'room area and cleanliness level' by providing the cleanliness targets, floor and ceiling plans, target air volume or speed, filtration requirements, power supply and control requirements, as well as estimated quantities and staging plans for each area.
FAQ: Can FFUs of the same size be directly interchanged? You cannot judge based on size alone. It is also necessary to check the air volume and static pressure, filters and sealing methods, electrical interfaces, control protocols and maintenance space under design conditions.
Frequently Asked Questions: Is the higher the number of FFUs, the better? Quantities should serve target airflow and cleanliness. Increasing FFU will also change the power supply, noise, energy consumption and return air conditions, which should be determined based on zoning calculations and on-site verification results.
