How does semiconductor FFU cooperate with AMC control? How to divide the work between particle filtration and chemical filtration
In semiconductor clean rooms, particulate matter and AMC are not the same thing
The air requirements of semiconductor clean rooms are often referred to as 'cleanliness'. However, in actual process environments, pollutants in the air are at least divided into two categories: one is suspended particulate matter, including dust, fibers, metal particles, microbial carriers, etc.; the other is gaseous molecular pollutants, namely AMC (Airborne Molecular Contamination), including acidic gases, alkaline gases, organic gases, doped gases, etc.
The sources, hazard pathways and control methods of these two types of pollutants are different. Particulate matter is mainly intercepted by HEPA or ULPA filters, while AMC requires adsorption or reaction removal by chemical filter materials. As the core equipment of clean room circulation filtration and air supply, FFU is mainly responsible for particulate matter control tasks. However, if the project has AMC control requirements, FFU and chemical filtration system need to be considered together instead of simply increasing the HEPA level.
In semiconductor FFU supporting projects, Aili Industries usually recommends clarifying the types of pollutants and target concentrations before deciding on the division of labor between FFU and chemical filtration to avoid mixing the two types of issues. For the basic structure of the FFU machine, you can refer toAili Industrial FFU fan filter unit。
Division of labor boundaries between particle filtration and chemical filtration
Particle filtration solves the problem of 'suspended solids or liquid droplets in the air'. HEPA filters have a clear filtration efficiency for 0.3 micron particles, and ULPA filters have higher efficiency for smaller particles. The FFU uses a fan to drive the air through the high-efficiency filter, trap the particulate matter on the filter material, and then send it to the clean area. The effectiveness of particle filtration is related to filter efficiency, seal integrity, supply air coverage and room airflow organization.
Chemical filtration solves the problem of 'gaseous molecules in the air'. The particle size of AMC molecules is much smaller than particulate matter and cannot be effectively intercepted by HEPA or ULPA. Chemical filters usually use activated carbon, impregnated activated carbon, ion exchange materials or other adsorption media to remove target gases through adsorption or chemical reactions. The effect of chemical filtration is related to the target gas type, concentration, filter material selection, contact time and replacement cycle.
The evaluation objects of the two are different. Particle filtration looks at particle count and filtration efficiency, while chemical filtration looks at target gas concentration and removal rate. Increasing the HEPA level from H13 to U15 will not automatically improve AMC issues, nor will it replace chemical filtration.
FFU's role in AMC control
FFU itself usually does not undertake the task of AMC treatment, but it can become one of the carriers of chemical filtration. In some semiconductor clean room solutions, FFU can be equipped with chemical filters to form a combined air supply unit of 'particle filtration plus chemical filtration'. The advantage of this configuration is that the air supply end handles particulate matter and gaseous pollutants at the same time, which is suitable for areas with local control requirements for AMC.
However, when FFU is equipped with chemical filtration, several additional issues need to be paid attention to. The resistance of chemical filter materials is usually higher than that of ordinary HEPA. When superimposed, it will affect the working point of the FFU, and the fan static pressure and air volume need to be rechecked. The thickness, installation method and replacement cycle of chemical filter materials are different from HEPA, which will affect the maintenance space and replacement path of FFU. The life of chemical filter materials is affected by target gas concentration and operating time, and cannot be processed according to HEPA replacement logic.
If the project requires FFU supporting chemical filtration, you can refer toFFU chemical filters understand the adapter structure. Aili Industrial also has a complete product line in chemical filtration and AMC molecular pollution control, which can be viewedChemical Filters and AMC Molecular Contamination Control Learn about filtration options for different target gases.
The impact of resistance superposition on FFU selection
When the FFU is equipped with both a particle filter and a chemical filter, the system resistance will increase significantly. The fan needs to maintain the target air volume under higher resistance, which places higher requirements on the static pressure capability of the FFU. If chemical filtration is directly installed according to the configuration of ordinary HEPA FFU, insufficient air volume, increased speed, increased noise, or increased motor load may occur.
Therefore, in the AMC control project, FFU selection should not only look at the efficiency level of HEPA, but also confirm the resistance characteristics, installation location and expected replacement cycle of the chemical filter. For areas that need to handle both particulate matter and AMC, it is recommended that the FFU, chemical filter, and room air supply system be accounted for as a whole, rather than selected separately.
Aili Industrial has complete production capabilities in FFU complete machines, chemical filters and system accessories. It can make overall accounting on the matching of fans, filters and controllers, helping projects maintain stable air supply performance after adding chemical filtration. Regarding the static pressure and air volume characteristics of different FFU structures, please refer toof DC fan filter unit .Learn about the specific configuration
AMC control is not just a filter issue
AMC control involves pollution sources, airflow paths, filter materials and monitoring methods, and cannot be solved by just one filter. In semiconductor clean rooms, AMC may come from outdoor fresh air, process equipment exhaust, chemical storage, personnel operations, construction material release, etc. If the source of pollution is not identified, adding chemical filtration only at the end of the FFU may not solve the problem of high local concentrations.
In actual operation, AMC control usually needs to be coordinated with fresh air treatment, process exhaust, return air organization and regional isolation. The function of FFU is to provide circulating filtered air supply. It can cooperate with chemical filtration to reduce the AMC concentration in the supply air, but it cannot replace source control, exhaust design and system monitoring.
For semiconductor projects, it is recommended to clarify the AMC objectives, pollution source locations, monitoring points and control strategies during the design stage, and then determine whether the FFU requires supporting chemical filtration, and whether the chemical filtration is installed inside the FFU, at the end of the AHU, or in an independent chemical filtration unit.
Issues that should be confirmed in advance during project communication
In semiconductor FFU and AMC control projects, it is recommended to confirm the following with the FFU manufacturer and chemical filtration supplier: target gas type and concentration range; AMC control targets and recommended filter materials; resistance characteristics and replacement cycles of chemical filters; air volume and static pressure performance of FFU after superimposing chemical filtration; installation location and replacement space of chemical filters; detection methods of particle filtration and chemical filtration; monitoring and replacement judgment conditions after system operation.
These issues need to be clarified in the selection stage to avoid later adjustments to the plan due to mismatched resistance or insufficient replacement space.
in conclusion
HEPA or ULPA in semiconductor FFU mainly controls particulate matter, and AMC gaseous pollution requires a separate chemical filtration solution. The two types of filtering tasks are different and cannot replace each other. FFU can be used as one of the carriers of chemical filtration, but the resistance, air volume, static pressure and maintenance conditions need to be rechecked.
Aili Industrial has complete production capabilities in FFU complete machines, HEPA/ULPA filters and chemical filters. It can provide supporting solutions for particle filtration and chemical filtration for semiconductor projects, helping projects complete the system division of FFU and AMC control on the premise of clarifying the type of pollution. If you are planning an AMC control solution for a semiconductor clean room, you can start withAili Industrial FFU fan filter unit to learn about the complete machine configuration, you can also viewHEPA and ULPA filters andChemical Filters and AMC Molecular Contamination Control Learn about filter material selection ideas.
