HVAC Control in the New Millennium.pdf - HVAC.Amickracing

Advanced HVAC Control, Information Technology and Open Systems 131Chapter 4Advanced HVAC Control,Information TechnologyAnd Open SystemsClean rooms represent space areas that are used for testing/analysis laboratories, in medical, military and electronic processingindustries. The optimization of clean room controls isan important area in the future of HVAC controls. Many ofthese concepts will be finding their way into building automation.The production of semiconductors must take place in a clean roomenvironment. Optimization of the clean room control system can reducethe cost of operation and the number of product defects. In semiconductormanufacturing, an area of 100,000 square feet (9290 square meters)can have a daily production worth of over $1 million.Semiconductor ManufacturingThe overall semiconductor fabrication process consists of the patterningof a sequence of successive layers. The patterning steps aretransferred into layers of the final system. The sequence of layers is usedto build up an integrated system.One process is the creation of a silicon dioxide insulating layeron the surface of a silicon wafer and the selective removal of sectionsof the insulating layer. This step begins with a bare polished siliconwafer. The wafer is exposed to oxygen in a high-temperature furnaceto grow a uniform layer of silicon dioxide on its surface. After thewafer is cooled, it is coated with a thin film of organic resist material.©2001 by The Fairmont Press, Inc. All rights reserved.