This is where the IC chips are made. A single chip may contain several hundred million transistors. Compared to transistors, a dust particle is huge and can easily ruin the chip. Fabs are thus extraordinarily clean. Indeed, the entire building functions as a four story high unit to produce one of the cleanest places on the face of the earth. In critical areas, there is less than one single dust particle per cubic meter of air. This is more than 100,000 times cleaner than a modern hospital's "clean" operating rooms.
