company news about What is the general class of modular cleanrooms in semiconductor factories?

What is the general class of modular cleanrooms in semiconductor factories?

Modular cleanrooms in semiconductor fabs are designed to meet stringent air cleanliness standards dictated by the specific manufacturing processes, primarily conforming to the ISO 14644-1 classification system. The most common levels are as follows:

1. ISO Class 4 (Equivalent to Fed-Std-209E Class 10) This is the highest level typically implemented in modular form. It is reserved for the most critical process areas, such as advanced node photolithography bays, key thin-film deposition zones, and EUV (Extreme Ultraviolet) lithography environments. These areas demand near-zero particle counts for particles as small as 0.1 μm. The modular cleanrooms achieve this through dense arrays of HEPA or ULPA filter Fan Filter Units (FFUs) in the ceiling, creating a unidirectional, vertical laminar airflow down to the raised floor. They are integrated with rigorous controls for temperature, humidity, and vibration.

2. ISO Class 5 (Class 100): This is the workhorse standard for core fabrication areas. The majority of modular cleanrooms for processes like diffusion, etching, ion implantation, and chemical mechanical planarization (CMP) in mainstream logic and memory fabs are built to ISO 5. They provide a controlled environment where the particle count for particles ≥0.5 μm is limited to 3,520 per cubic meter. The modular construction allows for efficient layout of process tools, utility chases, and return air plenums.

3. ISO Class 6 (Class 1,000): These are commonly deployed for slightly less critical zones, such as certain metrology areas, some assembly and packaging lines, wafer inspection stations, and clean material transfer corridors (AMHS). They are also suitable for production of power semiconductors or devices on mature process nodes.

4. ISO Class 7 (Class 10,000) and ISO Class 8 (Class 100,000): Modular cleanrooms at these levels serve support and ancillary functions. They are typically used for equipment service bays, chemical and gas supply areas (bulk delivery zones), gowning rooms, and wafer loading/unloading prep areas. They act as buffer zones to prevent contamination from reaching the higher-class core fab.