I. Introduction
With the continued advancement of technology and cleanrooms used in the production of sophisticated information technology devices, airborne molecular contamination (AMC), as well as particulate contamination, has become a crucial problem in the enhancement of production yield. As the critical dimension becomes smaller, cleanroom design concepts consequently change in focus, from concerns such as controlling the cleanliness level in the ballroom-type cleanroom to raising the cleanliness level in processing environments, like mini-environments and standard mechanical interface format (SMIF) systems [1]. The main advantage of mini-environments is the reduction of the area that requires a high degree of cleanliness, thereby decreasing the construction and operating costs of maintaining a cleanroom. Moreover, the effective isolation of a product from contaminants helps improve the product yield.