What is the difference between H14 EFU and U15 EFU? Comparison of structure, performance, control and applicable scenarios

The difference in samples between H14 EFU and U15 EFU is usually simplified into two efficiency numbers: H14 has a filtration efficiency of MPPS particles ≥ 99.995%, and U15 ≥ 99.9995%. The number is an order of magnitude different, but if you only look at this line when selecting a model, it is easy to overlook the fact that when the filter level increases from H14 to U15, the fan operating point, sealing requirements and applicable clean areas of the EFU will also change accordingly. The relationship between H14 EFU and U15 EFU is not 'the same machine with one filter paper', but the result of the interaction of the filter resistance characteristics, the matching conditions of the whole machine and the target cleanliness level. Aili Industrial's 70mm ultra-thin EFU supports filtration level configurations from H13/H14 to U15/U16. The matching of the filter and fan working points is completed within the same manufacturing system, making it easier for equipment manufacturers to select the corresponding complete machine according to the clean area level.

Structural differences: The filter grade changes, and the box sealing and resistance conditions change accordingly.

The structural differences between H14 and U15 at the filter level are first reflected in the filter material and testing requirements. H14 belongs to the HEPA group and U15 belongs to the ULPA group. According to the classification logic of EN 1822, both Group H and Group U filters need to be tested for leakage one by one, but the local penetration rate requirements of Group U are more stringent: the local efficiency of H14 is ≥99.975%, and that of U15 is ≥99.9975%. This means that the U15 filter has higher quality control requirements for filter element folding, frame sealing and glue lines, and the sealing interface between the box and the filter also needs to match a lower allowable leakage amount.

In terms of resistance, the improvement of filter grade is usually accompanied by changes in the structure of the filter material. Taking a certain brand of plate filters of the same size as an example, there are differences in the initial resistance between H14 and U15 under the same surface wind speed, and the resistance of models with greater depth is different. The EFU fan is selected according to a certain resistance range. If you change from H14 to U15 without checking the fan working point simultaneously, the actual air volume may deviate from the design value. For the verification method of filter resistance and fan matching, please refer toHow to choose EFU filter without partition? Efficiency, resistance, sealing and complete machine matching methods are explained.

Performance differences: What 'half an order of magnitude' in efficiency means

From a numerical point of view, the penetration rate of H14 is ≤0.005% and that of U15 is ≤0.0005%, which is a ten-fold difference. In the actual application of equipment-side EFU, whether this gap is important depends on the sensitivity of the process area covered by the EFU air outlet surface to particles.

For the internal microenvironment of most equipment, H14 EFU combined with reasonable laminar flow organization can already cover local clean conditions of ISO level 5 or better. The applicable scenarios for U15 EFU are usually concentrated in links with stricter particle control requirements, such as key stations where wafers are exposed in the semiconductor front-end process, near the bonding interface in advanced packaging, or in the microenvironment related to photolithography in the panel array section. In these scenarios, a single submicron particle can cause defects, and efficiency margins need to be wider. The application scenarios of Aili Industrial's 70mm ultra-thin EFU cover the micro-environments of semiconductor equipment such as EFEM and Load Port, and support the selection of H14 or U15 filtration levels according to the clean area of ​​the equipment.

But the U15's efficiency advantage doesn't come for free. After the filter resistance increases, the fan needs to output higher static pressure to maintain the target air volume, and power consumption and noise change accordingly. When choosing U15 EFU, you should check the air volume margin of the fan under the final resistance condition, rather than just looking at the efficiency value on the filter sample. Regarding the relationship between fan operating point and resistance change, please refer toHow to view the EFU fan performance curve? air volume, static pressure, power and operating point .Description of

Control difference: the speed adjustment strategy should follow the filter resistance

The difference between H14 EFU and U15 EFU at the control level comes from the impact of filter resistance on the fan operating point. If there are both H14 and U15 areas in the same equipment, the shared speed adjustment command may not necessarily meet the air volume targets under both filters at the same time. The resistance of the U15 filter is usually higher than that of H14 of the same size, and the air volume may be lower at the same speed. The controller needs to adjust the speed setting or speed mapping according to the actual filter configuration.

For EFUs that support Modbus communication, the speed adjustment mapping relationship should be clearly marked in the confirmation diagram: whether the written value corresponds to the rotation speed percentage or the wind speed value, and whether the upper limit needs to be adjusted under U15 configuration. If the EFU adopts constant air volume control logic, the controller needs to be able to identify changes in filter resistance and automatically compensate for the rotation speed, otherwise the air volume will gradually decrease after the filter accumulates dust. Aili Industrial EFU control solution supports RS485/Modbus communication, and the speed adjustment parameters can be configured according to the filter level. The equipment manufacturer can list the speed adjustment settings of the H14 and U15 areas separately during the diagram confirmation stage. For check points on controller speed regulation and communication functions, please refer toWhat does the EFU controller do? speed regulation, communication, linkage and exception handling .Instructions on

Applicable scenarios: H14 covers most equipment-side micro-environments, and U15 focuses on highly sensitive workstations

H14 EFU has a wider range of applications. For general clean areas inside the equipment, transmission mechanism areas, and workstations that are sensitive to particles but do not directly expose the wafers, H14 can usually be satisfied with reasonable air duct and wind speed design. For equipment-side purification in pharmaceutical, medical device, food and other industries, H14 is also a common choice.

U15 EFU is more suitable for scenes with 'extremely low particle tolerance'. Key areas where wafers stay or pass through in semiconductor front-end equipment, advanced packaging bonding stations, and near the internal light path of optical inspection equipment. These locations have higher requirements for the control of submicron particles than general equipment microenvironments. But U15 is not the default option for all equipment-side projects - if the clean area inside the equipment only requires ISO level 5 or looser conditions, H14 EFU is more pragmatic in terms of resistance, power consumption and cost. Regarding the method of dividing the clean area inside the equipment, please refer toHow to configure advanced packaging equipment EFU? the key points of clean area, air volume filtration and equipment interface .Area classification ideas in

Misunderstandings to avoid

It should be avoided to simplify the difference between H14 and U15 into efficiency figures and ignore the changes in the fan operating point. It should be avoided to directly replace the H14 project with U15 without checking the final resistance air volume. It should be avoided to mix H14 and U15 in the same partition without configuring the speed adjustment parameters separately. It should be avoided to select U15 by default when only H14 is needed in the clean area of ​​the equipment, thereby increasing unnecessary resistance and power consumption. The core of selecting H14 EFU and U15 EFU is not 'which grade is higher', but rather the verifiable correspondence between filter efficiency, resistance characteristics, fan matching and target clean area.

Related questions and answers

When replacing H14 EFU with U15 EFU, do I need to replace the fan?
It is not necessary to replace the fan, but the working point must be rechecked. The resistance characteristics of the U15 filter may be different from those of the H14, and the air volume may change at the same rotation speed. If the fan can still maintain the target air volume under the U15 final resistance condition and leaves a margin, it can be used; if the margin is insufficient, the fan specification or speed regulation strategy needs to be adjusted.

Do all areas within the device need to use U15?
unnecessary. According to clean areas, U15 is used for sensitive workstations such as wafer exposure or bonding interfaces, and H14 is usually sufficient for transfer areas or general microenvironments. Using U15 in the entire area will increase filter resistance and fan power consumption, while the benefits will be concentrated in a few sensitive workstations. Partitioned configuration is a more pragmatic approach.

What is the difference in control between H14 and U15 EFU?
Mainly the configuration of speed regulation mapping and constant air volume logic. The U15 resistance is on the high side, and the actual air volume under the same command value may be lower than the H14 configuration. The controller needs to adjust the speed setting according to the filter level. If the EFU supports constant air volume control, you need to confirm whether the controller can compensate normally within the U15 resistance range.

Related articles

How to choose EFU filter without partition? Efficiency, resistance, sealing and complete machine matching methods

What does the EFU controller do? Speed ​​regulation, communication, linkage and exception handling

How to configure advanced packaging equipment EFU? Key points of clean area, air volume filtration and equipment interface

Key points for selection and acceptance inspection

Aili Industrial EFU selection and procurement support

Aili Industrial's 70mm ultra-thin EFU supports filtration level configuration from H13/H14 to U15/U16. The operating points of the filter and fan can be checked by level in the confirmation diagram, and the speed adjustment parameters can be configured by partition. The equipment factory can submit the filtration level requirements of each area according to the clean area. Aili Industrial will match the fan specifications and speed settings accordingly, and the prototype data and confirmation drawings will be archived together.

Learn about Aili Industrial EFU products and customized configurations. Check out the compact models.70mm ultra-thin EFU , the entire machine structure can be viewedEFU equipment fan filter unit , filter package can be viewedHEPA and ULPA air filters , the control scheme can be viewedDC speed regulating EFU equipment fan filter unit . Please submit the equipment clean area division, target level and estimated quantity of each area to facilitate confirmation of H14/U15 configuration and fan matching plan.