The chemical filter of the wafer temporary storage cabinet should be selected according to the protection requirements, target gas, circulating air volume and material release in the cabinet. Cabinet appearance or room cleanliness cannot replace the gas and airflow conditions of the microenvironment. The temporary storage cabinet is a small space, and its filtering logic is not exactly the same as the room-level configuration.

First determine what needs to be protected inside the cabinet

The filtering target of the wafer temporary storage cabinet depends on what is placed in the cabinet, how long it is kept, and how the cabinet door is opened. The temporary storage cabinet may be used for a short stay between processes, or it may be used for storage of several hours or even longer; the cabinet may only store wafer boxes, or it may store both carriers and packaging materials. These differences impact target gas inventories and capacity requirements. The protection object should be clearly defined as the wafer surface, the environment inside the box or the air in the cabinet, and then the detection points and filtering positions should be determined. If we just generally say 'the inside of the cabinet must be clean', there is no comparable basis for selection.

The air path in the cabinet determines the position of the filter section

The circulation air path of the temporary storage cabinet is usually shorter than that of the air conditioning box, and the position of the filter section has a more direct impact on the airflow coverage. Common arrangements include cabinet top circulation, back air return, side air supply, etc. The filter section should be placed where the airflow can cover the wafer storage area, rather than just dealing with a certain corner of the cabinet. If the cabinet door is opened frequently, whether the outside air can be processed by the circulating filter section in time after entering also depends on the air supply direction and air volume. Regarding the difference between microenvironment and room conditions, please refer toWhat molecular contaminants need to be assessed for FOUP storage areas?。

Circulating air volume and filter section resistance must match

The circulating air volume in the cabinet is usually limited, and the resistance of the filter section directly affects the circulation effect. When the air volume is low, the number of air exchanges in the cabinet is insufficient, and pollutants may accumulate locally; when the filter section resistance is high, the fan capacity is insufficient, causing the actual circulation volume to be lower than the design value. When selecting a model, you should check the circulating air volume in the cabinet, the resistance of the filter section at this air volume, and whether the fan can provide sufficient static pressure. The V-shaped structure provides a large filtration area in a limited space, helping to control surface speed and resistance at low air volumes. For structural comparison in compact space, please refer toMAU choose box type or V-type chemical filter?。

Cabinet materials and seals are also sources of release

The sealing strips, coatings, plastic parts and label materials inside the temporary storage cabinet may themselves release organic or acidic components. The space inside the cabinet is small and the number of air exchanges is low. The cumulative effect released by these materials may be more obvious than the room environment. In addition to paying attention to external input when selecting a model, you should also understand the outgassing situation of the cabinet material. If necessary, control it through circulating filtration or material replacement in the cabinet. For issues involving low outgassing materials, please refer toWhat are the implications of low outgassing chemical filter media for sensitive processes?。

Aili industrial supporting equipment

For micro-environment projects such as wafer temporary storage cabinets, we usually first confirm the circulating air volume in the cabinet, the installation space of the filter section and the protection objects, and then compare the filter element form and media configuration. Aili Industry can provide selection packages for box-type, flat-plate and V-type chemical filtration products. For box-type MAU packages, please refer toMAU box type chemical filter , product series can be viewedChemical filter product range . Device-side applications can useChemical filter FFU type, integrated chemical adsorption layer withHEPA/ULPA filter particle filtration, the structure of chemical first and then particles is suitable for micro-environments such as temporary storage cabinets that require both AMC and particles. The compact filter element can be adapted non-standardly according to the cabinet space and circulating air volume. The manufacturing end covers independent R&D and production of motors and fans, control systems, sheet metal and complete machine assembly. The interface and air volume matching between the filter section and the cabinet circulation fan can be checked in the same package. The specific gas effect, applicable environment and replacement cycle still need to be verified based on the corresponding configuration data and on-site working conditions. The actual results are subject to on-site leak detection and gas detection results.

Related questions and answers

The circulation air volume in the temporary storage cabinet is small, can the chemical filter still work?
Yes, but the filter section resistance and fan capacity need to match. When the air volume is small, a structure with low surface velocity and moderate resistance should be selected, and the number of air exchanges in the cabinet should be confirmed to meet the requirements.

There is no obvious smell in the cabinet, do I still need to install a chemical filter?
Smell is not the only basis for judgment. The very low concentration of some sensitive components may also affect the wafer. This should be judged based on the process requirements and the gas release conditions of the materials in the cabinet.

Can Aili Industrial make non-standard filter elements according to the temporary storage cabinet space?
The compact filter element structure can be checked according to cabinet size and circulating air volume, and the chemical filter FFU form can integrate chemical and particle filtration. The specific configuration needs to be confirmed based on product information and site conditions.

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Key points for selection and acceptance inspection