cleanroom

Cleanrooms are controlled environments with minimal airborne particles, essential for semiconductor manufacturing. **Why needed**: Particles on wafers cause defects. Modern chips have features smaller than particles - even one dust speck ruins circuitry. **Contamination sources**: People (skin cells, hair), equipment, materials, outside air. Humans are biggest source. **Cleanroom features**: Filtered air (HEPA/ULPA), positive pressure, controlled temperature/humidity, special flooring, monitored particle counts. **Gowning**: Full bunny suits, gloves, face masks, shoe covers required. Strict protocols for entry/exit. **Airflow**: Laminar flow from ceiling to floor. Air changes 300-600 times per hour. Particles swept away. **Monitoring**: Continuous particle counting, environmental sensors, regular validation. **Cost**: Very expensive to build and operate. Significant portion of fab construction cost. **Cleanroom classes**: Class 1, 10, 100 etc. based on particles per cubic foot. Leading fabs use Class 1. **Beyond semiconductors**: Also used for pharmaceuticals, biotech, optics, aerospace. **Maintenance**: Filter replacement, regular cleaning with special materials, protocol enforcement.