As companies grow their capacity in multiple buildings there are increasing challenges with the automated material handling systems (AMHS) used to transport the wafers between two or more facilities. In some cases, the links used to perform these transports can become a constraint for the entire system. The problem grows more difficult as the expansion plan extends further into the future, making it harder to predict throughput requirements. This study discusses a particular throughput prediction tool as well as different approaches for evaluating designs. The approaches discussed include: integrated vehicle/conveyor model using static tool (Network approach), segregated dynamic models for conveyor/vehicle system, and integrated vehicle/conveyor dynamic model. The pros/cons of these approaches are discussed based on different use cases. The paper finishes by discussing the strategic advantages of factories performing expansion analysis early in the design of the factory and the importance to continue validating and improving these methods. INTRODUCTIONThe first fab on a semiconductor manufacturing site is often not the last fab for the site. As demand for the company increases, it is often advantageous to leverage the existing infrastructure for the additional capacity a new fab can provide. Just as the water mains, electrical power, and transportation needs encompass the long term capacity needs when a site plan is developed, the AMHS design should take into consideration potential expansion requirements for the site. Although it is possible to design new fabs to operate completely independent from the original fab, there are often cost advantages to adding additional factories by leveraging capacity in the already existing fab(s). This approach can create a flow of material back and forth between new and old fab(s) during the ramp up period through full production. To support this flow of material, AMHS designers face several questions that need to be addressed:  How big should interconnects be?  How many and where should they be located?  What are the dimensions of the hallways or bridges that would support them? Also, the designers will need to ensure the delivery systems will meet required inter-fab throughput without disrupting the flow inside the original fab or the new fab. If these questions are not addressed success-978-1-4673-4781-5/12/$31.00 ©2012 IEEE

No abstract

No abstract

Today's 300mm semiconductor facilities rely almost completely on Automated Material Handling Systems (AMHS) to transport wafers to equipment and storage areas in the wafer fabrication plant (fab). As the cost of equipment increases and the process technology becomes more and more sensitive to delivery times between steps, AMHS performance has become increasingly important to overall factory performance. Current AMHS design methods focus primarily on optimizing the balance between AMHS cost and AMHS performance. Understanding the influence of AMHS performance on fab operations has become an area of focus during the design process.This paper proposes a methodology to correlate AMHS performance measurements with simulated fab performance measures using a linked AMHS-fab model. This methodology facilitates model setup, scenario modification, model linkage, and calculations of performance impact. A sample evaluation study demonstrates the validation and analysis process, and derives conclusions applicable during the AMHS design process.