Abstract
In the semiconductor industry, machine tools purchases require an enormous amount of capital, which is approximate 60-70% of initial fab expenses for machine tools. Therefore the semiconductor manufacturing companies are faced on important capital investment decisions for the procurement of new types of machine tools for their facilities. In order to meet the forecast demand, the manufacturer may need to procure additional machine tools. In fact, it is a challenging task to procure machine tools efficiently because of rapid changes in technology and products. The thesis focuses on a machine tool management problem of semiconductor industry to determine tool planning using multiple types of machine tools producing various products. We will take into consideration the COO model as a unit cost, the capacity shortages, and capacity overflows simultaneously. In order to present investment decisions on procuring new machine tools and to examine the problem over multiple time periods within a single wafer facility, we analyze the tool capacity planning problem under uncertainty in demand and formulate the problem as a mixed integer problem to minimize the expected capacity shortage costs, capacity overflow costs, and production costs. Finally, we study the performance during different time periods to discuss different situation.