What is the difference between ISO 5 and ISO 7 cleanroom?

ISO 5 and ISO 7 are classifications within the ISO 14644 standard for cleanrooms. The following are the main differences between them:

Particle Concentration

• ISO 5 Cleanroom：In an ISO 5 cleanroom, the maximum allowable number of particles of size 0.5 µm and larger is 3,520 particles per cubic meter of air. For particles of size 5 µm and larger, the limit is 29 particles per cubic meter. This extremely low particle count makes ISO 5 cleanrooms suitable for very sensitive processes where even a small number of particles can cause significant issues. For example, in semiconductor manufacturing, during the production of advanced microchips with extremely small feature sizes, an ISO 5 cleanroom may be required to prevent particle contamination that could lead to defects in the circuitry.
• ISO 7 Cleanroom：An ISO 7 cleanroom has a much higher allowable particle count. For particles of size 0.5 µm and larger, the limit is 352,000 particles per cubic meter of air, and for particles of size 5 µm and larger, it is 2,930 particles per cubic meter. While this is still a relatively clean environment compared to normal industrial or indoor spaces, it is not as clean as an ISO 5 cleanroom. ISO 7 cleanrooms are suitable for less sensitive processes where a moderate level of particulate control is sufficient. For instance, in some pharmaceutical manufacturing processes where the product is not as highly sensitive to extremely small particles as in certain semiconductor applications.

Cost and Complexity of Construction and Maintenance

ISO 5 Cleanroom

• Construction Cost: Building an ISO 5 cleanroom is more expensive. It requires more advanced filtration systems, such as Ultra – Low – Penetration Air (ULPA) filters, which have a higher filtration efficiency compared to the High – Efficiency Particulate Air (HEPA) filters typically used in ISO 7 cleanrooms. The construction materials also need to be of higher quality to minimize particle generation. For example, smooth, non – shedding wall and ceiling materials are essential.
• Maintenance Cost: The maintenance of an ISO 5 cleanroom is also more costly. ULPA filters are more expensive to replace than HEPA filters, and the cleanroom requires more frequent monitoring and calibration of environmental parameters such as air – flow, temperature, and humidity to maintain the extremely low – particle environment. Additionally, personnel access and operating procedures need to be more strictly controlled, which may involve additional training and equipment for decontamination.

ISO 7 Cleanroom

• Construction Cost: The construction cost of an ISO 7 cleanroom is relatively lower. HEPA filters can be used for filtration, which are more cost – effective. The requirements for construction materials are less stringent, although they still need to meet certain standards for cleanliness.
• Maintenance Cost: Maintenance is less expensive compared to an ISO 5 cleanroom. HEPA filters have a longer lifespan in an ISO 7 environment (as the particulate load is higher, but still within the filter’s capacity), and the cleanroom is more forgiving in terms of minor fluctuations in environmental parameters. The procedures for personnel access and operation are also less complex, reducing associated costs.

Applications

ISO 5 Cleanroom

• Semiconductor Industry: As mentioned earlier, it is used in the production of high – end microchips, especially in processes such as lithography where the smallest particles can cause defects in the extremely fine patterns on the chip.
• Biomedical and Pharmaceutical Research: In certain types of biomedical research where extremely pure cell cultures are required, such as in some gene therapy or stem cell research applications. Also, in the production of some high – value, highly sensitive pharmaceuticals where even a small number of particles could affect the drug’s efficacy or safety.

ISO 7 Cleanroom

• Semiconductor Packaging: In the semiconductor industry, ISO 7 cleanrooms are often used for packaging the chips produced in the ISO 5 cleanroom environment. The packaging process is less sensitive to particle contamination compared to the chip manufacturing process itself.
• General Pharmaceutical Manufacturing: For the production of many common drugs, such as tablets and capsules, an ISO 7 cleanroom can provide a sufficient level of cleanliness to prevent major contamination issues and ensure product quality.