TABLE OF CONTENTS Selection of the clean air strategy is the first step in the design of a cleanroom. Every cleanroom is a trade-off between cleanliness and cost. Whatever the final design, every cleanroom is built on basic principles. The primary design is a sealed room that is supplied with clean air, is built with materials that are noncontaminating, and includes systems to prevent accidental contamination from the outside or from operators.
The inside of a cleanroom is constructed entirely of materials that are nonshedding. This includes wall coverings, process station materials, and floor coverings. All piping holes are sealed, and even the light fixtures must have solid covers. Additionally, the design should minimize flat surfaces that can collect dust. Stainless-steel materials are favored for process stations and work surfaces.
Both the design of a cleanroom and its operation must be set up to keep dirt and contamination from getting into the room from the outside. Figure 5.15 shows a layout for a typical fab processing area. The following nine techniques are used to keep out and control dirt:
Adhesive floor mats
Gowning area
Air pressure
Air showers
Service bays
Double-door pass-throughs
Static control
Shoe cleaners
Glove cleaners
Adhesive floor mats. At the entrance to every cleanroom is a floor mat with an adhesive surface. The adhesive pulls off and holds dirt adhering...
