Semiconductor industry accounts for 1.3% - 2% of the total US electricity consumption in the manufacturing sector. Energy in the form of electricity is required to operate the process tools, maintain the clean room conditions, operate Heating Ventilation and Air conditioning units, and Chillers, etc. The process tools account for 40% of the operating costs in a semiconductor fabrication unit. Since a significant amount of energy is used by the process tools, it becomes necessary to determine process parameters which govern energy. A model is built in this study to estimate the energy requirement of any particular process in semiconductor manufacturing based on the input variables. It is intended to enable the estimation of process energy beforehand by analysis of process parameters governing energy. This paper also reports a sensitivity analysis of process variables with respect to energy. Often physical energy measurement in semiconductor fabrication unit is time consuming as well as uneconomical. A research in this area will help the production managers in the Semiconductor fabrication facilities to effectively select the production parameters and use the process tools based on the results obtained from the analysis.