ABSTRACT
A clean room is an enclosed space bounded by a leak-free structure such that the only air entering the environment passes through banks of high-efficiency particulate air (HEPA) or ultralow penetration air (ULPA) filters. The purpose of a clean room is to provide as particle-free an environment as possible for manufacturing. Thus, a clean room is a key component of the semiconductor manufacturing process, and like any other piece of equipment, it must be properly designed, built, and maintained to function effectively. The evaluation of clean-room performance is an inexact science. Consequently, it is not easy to predict how a clean room will perform under any given set of circumstances. This chapter provides a simple means for obtaining an approximate estimate of contamination levels in a clean room under various conditions. It presents representative data to show contamination levels in an operating clean room from some typical (and some atypical) particle sources.
