ALMOST EVERYTHING IS HAPPENING HERE!

DEFINITION: Cleanrooms (see above) are chambers in which huge ventilators and filters are purifying and cleaning the air.

Air circutlation in cleanroom (see picture below):

• The air is pumped out, filtered and returned to the Clean Room.
• The small particles stick to the fibers in the filter due to electrostatic forces, while large particles are blocked by the filter.

PURPOSE: avoid contaminationa and defects in devices.

• Particles have to be smaller than 1/2 of the minimum feature size on wafer, in order not to influence the process. Dust particles are usually responsible for defects. Killer defects = are defects situated in the critical area of the devices, which causes the device not to function. By reducing the number of dust particles, the devices become more reliable.