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This research was sponsored by the research grant (NSC 89-2213-E-006-142) from the National Science Council of Taiwan, ROC.
Introduction
The layout design has a significant impact on the performance of a manufacturing system (Allegri, 1984; Tompkins et al ., 1996). Layout design problem has been an active research area in the past few decades (Meller and Gau, 1996); however, design algorithms specifically designed for semiconductor wafer fabrication facilities (fab) are rare and/or may not be adequate to solve a real-world design problem (Peters and Yang 1997).
Existing literatures for a layout design problem often fall into two major categories as algorithmic and procedural approaches. Algorithmic approaches usually simplify both design constraints and objectives in order to reach a surrogate objective function which solution can then be obtained (Peters and Yang, 1997; Yang and Peters, 1997; Cardarelli and Pelagagge, 1995; Geiger et al. , 1997). These approaches usually only involve quantitative input data. Their design solutions are easier to evaluate by comparing their objective function values.
The outputs from algorithmic approaches often need further modifications in order to satisfy detailed design requirements such as department shapes, utilities supply, material handling systems, ergonomics concerns, work-in-process storage, space utilization, etc . Advanced training in mathematical modeling techniques are often prerequisites for a designer to use algorithmic approaches to solve a fab layout design problem. Accordingly, many semiconductor industries hesitate to adopt algorithmic approaches as their design methodologies.
Procedural approaches can incorporate both qualitative and quantitative objectives in the design process (Padillo et al. , 1997; Apple, 1977; Muther, 1973). For these approaches, the design process is divided into several steps that are then solved sequentially. The success of a procedural approach implementation is dependent on the generation of quality design alternatives that are often from the outputs of an experienced designer. Thus, the inputs from area experts during the design process are considered to be a must towards an effective fab layout design. It is often the last step for a procedural approach to evaluate the design alternatives. The choice of the final design is often difficult when multiple objectives are considered.
A fab design problem exposes the strong properties of a multiple objective decision problem. For this instance, an algorithmic approach may not be adequate in providing...