Cleanroom — an environmentally controlled manufacturing space with extremely low levels of airborne particles, essential for semiconductor fabrication.

Classification (ISO 14644-1)

• Class 1 (ISO 3): ≤10 particles/m$^3$ at 0.1um. Leading-edge fabs
• Class 10 (ISO 4): ≤100 particles/m$^3$. Standard for lithography areas
• Class 100 (ISO 5): ≤3,520 particles/m$^3$ at 0.1um. General fab areas
• Class 1000 (ISO 6): Less critical process areas

For comparison: Outdoor air has ~35 million particles/m$^3$

How It Works

• HEPA/ULPA filters remove 99.999%+ of particles
• Laminar airflow pushes particles downward
• Positive pressure prevents outside air infiltration
• Temperature: 21±0.5C, humidity: 43±5% RH

Personnel Protocols

• Gowning: Bunny suit, hood, gloves, booties, face mask
• Humans shed ~600,000 particles/minute — the biggest contamination source
• Air showers before entry

Why It Matters: A single 50nm particle on a wafer can kill a transistor. Modern chips have features smaller than most airborne particles.