How to choose between EFEM internal HEPA and factory terminal HEPA?

The specifications of the filters in these two positions may have the same efficiency rating, but the things to focus on when selecting are completely different.

EFEM is part of the equipment, and the filters inside must follow the equipment structure; the end of the factory building is part of the clean room system, and must cooperate with the ceiling, air duct and control system. If you choose the two as the same thing, it is easy to have problems with the interface, air volume or maintenance methods.

On the device side, first check where the sensitive areas are

The core inside EFEM is the wafer transfer path. Manipulator movements, door opening movements, and near cavity interfaces have the highest requirements for particle control.

The first step in selection is not to determine the grade of the filter element, but to draw the air flow path: where the air enters, which structures it passes through, which sensitive locations it covers, and where it is discharged. The internal space of EFEM is compact and there are many structural parts. The air flow is easily blocked by mechanical arms, door panels and cables. In addition to filtration efficiency, the uniformity and coverage of face air velocity are often more critical.

Specific to the product level, EFEM generally matches internal EFU is used in the fan filter unit at the equipment end. The power and air supply structure are provided by EFU, and the internal HEPA/ULPA air filter . Therefore, when selecting a model, you should look at the following: the air supply capacity of the EFU within the usable height of the equipment, the resistance of the filter element at the target air volume, and whether the interface between the two can be installed and replaced in a limited space.

What the factory looks at is system continuity

The filter at the end of the factory building is installed on the ceiling or high-efficiency air supply outlet, and serves the entire clean room or a large area.

The focus here is different from the equipment side: it must match the large-area air supply system, and the air volume is determined by the system distribution; it must correspond to the ceiling structure, FFU or air-conditioning box interface; the interchangeability and maintenance convenience during mass installation must be considered. The replacement of the terminal filter often involves production shutdown arrangements, so systemic factors such as interface standardization and spare parts consistency are more important.

Common configurations on the factory side include FFU fan filter unit and high-efficiency air supply outlet, the former comes with its own fan and filter, while the latter needs to be matched with the box and sealing structure. When making specific selections, there are two sets of ideas for checking the end interface and the device side.

The same grade cannot be directly interchanged.

Assuming that H14 is used inside EFEM and at the end of the factory, can the same filter element be used?

Not in most cases. The outer frame size, sealing method, installation direction, and disassembly and assembly paths are all different. The filter element inside the EFEM is limited by the equipment space and may be a small-sized non-standard structure, and the sealing method must also match the EFU box; the filter element at the end of the factory building is closer to the standardized size, and the sealing method may be a gasket or a liquid tank.

Even if the dimensions are coincidentally the same, the maintenance methods are different. The impact on equipment operation must be considered when replacing the equipment, and ceiling work and system shutdown arrangements must be considered when replacing the factory. When selecting models, select them according to their respective application scenarios. Do not assume that the same grade can be used universally.

Verification records should also be separated

The acceptance of the equipment is based on local wind speed, installation leak detection and particle control results. The test conditions are set according to the operating status of the equipment.

The acceptance of the factory is carried out according to the clean room system plan, looking at the air volume, air flow organization and space cleanliness.

The two types of records are kept separately, corresponding to their respective filter numbers and installation locations. When a problem occurs later, it can be quickly determined whether it is a problem within the equipment or the factory system. If the equipment-side interface involves the sealing structure of the liquid tank, it is necessary to check the matching status of the blade edge and the tank body when replacing it. For details, please refer to the relevant interface instructions.

About Aili Industrial’s equipment and factory supporting equipment

Ai Li industrial The EFU equipment-side fan filter unit supports ultra-thin structure and small size customization, and can be matched with HEPA/ULPA air filters are used inside equipment such as EFEM; also available FFU fan filter unit and high-efficiency air supply outlet are used at the end of the factory building.

Since the fans, motors, control systems, sheet metal and filters are in the same manufacturing system, the equipment side and the factory side can be configured according to their respective structural constraints, and there is no need to use the same filter element to adapt to both scenarios. For EFEM projects, it is recommended to provide the internal structure diagram of the equipment, available height, target area and wafer transfer path to facilitate the judgment of the equipment-side air supply solution. Specific performance is subject to product technical data and project acceptance results.