Energy and Operational Benefits of Thermoelectric Chillers in Semiconductor Manufacturing

摘要

Semiconductor manufacturing is a high-tech industry that relies heavily on automated tools in the fabrication process. With technologies down to 0.18micron and even smaller line widths, semiconductor products are extremely sensitive to produce, and many manufacturing tools require dedicated process cooling that is typically provided in the form of a dedicated conventional vapor compressor chiller. In 2010 National Semiconductor’s Portland, Maine facility retrofitted forty-nine existing vapor compressor chillers to thermoelectric chillers. This paper details the retrofit project and the significant energy savings that were realized. National Semiconductor Maine (NSME) is a Class 1 200mm wafer fab with 80,000 square feet of manufacturing space. In an effort to reduce the considerable energy associated with wafer fabrication, NSME installed forty-nine Solid State Cooling ThermoRack 1200 W thermoelectric chillers. Thermoelectric chillers (TECs) utilize the Peltier effect in order to transfer heat through electron flow. The TECs reduce the energy associated with process cooling and significantly reduce the amount of heat rejected into the fabrication space, thereby reducing the load on the space cooling systems. On average, direct energy use was reduced by 1.873 kW per retrofitted chiller with total (direct and indirect) annual electric savings of 827,976 kWh. The project was partially funded through Efficiency Maine’s custom incentive program, which provides cash incentives for projects that demonstrate electrical energy savings meeting prescribed simple payback and benefit-cost ratios. Due to the success of the project in terms of energy savings and process stability, National plans to install an additional fifty thermoelectric chillers in 2011. A review of the literature on solid state or thermoelectric cooling reveals little in the way of case studies or commercialized products and focuses instead on the theoretical and experimental aspects of the technology. This paper will report on the details of the installed system, and pre- and post-metering results.