| Summary: | 碩士 === 國立臺北科技大學 === 電機與能源研究所 === 88 === Semiconductor manufacturing industry is not only a technology-intensive but also an energy-intensive industry. According the United States Environment Protection Agency (EPA), the semiconductor industry of USA consumed more than 8 billion kWh in 1996 【13】. This large consumption of electricity, primarily produced by fossil fuel, has some consequences. It will produce large amount of the greenhouse gas (GHG), carbon dioxide, as well as other pollutants. Energy consumption/conservation for the semiconductor industry has not yet been discussed intensively in Taiwan. Very few energy survey studies were conducted for the semiconductor industry of Taiwan, although most of the fabs are clustered in the Hsinchu Scientific-Based Park. Therefore, the objectives of this study are: (1) to identify/compare the energy consumption levels for the overall fab use, (2) to locate the opportunities for energy-saving in the participated fabs, (3) and to distinguish/improve the energy and airflow characteristics provided by the axial fan type system or an alternative Fan Filter Unit (FFU) type system at the design stage systematically by using computational fluid dynamics (CFD) techniques.
This thesis includes three parts. First, energy survey results for nine semiconductor fabs in Taiwan area are reported. The results show that the energy data per unit area of the fabs are: the average electricity power is 2.18 kW/m2 and the average cooling load is 0.434 RT/m2. The average electric energy consumption per unit product (wafer) area is 1.432 kWh/cm2, and that is consistent with the data (3.1 kWh/cm2 in 1983 to 1.41 kWh/cm2 in 1995) reported by the U.S. Department of Commerce and Dataquest. Facility systems are the largest category of electric energy consumption in the fabs and constitute about 56.6% of total electric energy consumed in the fabs. Hereby the facility systems include chiller plant, makeup air system, recirculation air system, exhaust air system, nitrogen system, compressed dry air system, process cooling water, vacuum system and ultra-pure water system. The next highest area of energy consumption is the process tools category that accounts for 40.4% of energy consumed in the fabs. Analyses on the factors of energy consumption are presented. Detailed comparisons of energy use by facility component are illustrated. Best practices for energy saving reported by participated fabs are also discussed.
Second, the operational characteristics of two types of uni-directional clean room recirculation systems i.e. an axial type clean room and a FFU type clean room are investigated numerically. The results show that the performance of the FFU system is generally superior to that of an axial fan system because of such factors as non-uniformity of the ULPA filter face velocity, deflection angle of airflow in the working zone, and energy consumption.
Third, a correlation for the variation of the non-uniformity of filter face velocity is achieved for axial type clean rooms with two hundred case studies by CFD. This correction is helpful in the design of the geometry of clean room supply air plenum (SAP).
In general, this thesis provides significant information to the design and energy-saving for semiconductor clean rooms.
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