Requirements for AMHS in 450 mm era

When examining new configuration for manufacturing systems for 450 mm wafers, it is important to build logical models of whole or parts of fabs that include AMHS (automated material handling system), and then investigate behaviors of them. This paper presents a logical model of a part of a fab that includes production tools and AMHS. It shows CET (carrier exchange time) becomes more important for AMHS design in 450 mm fabs than in 300 mm fabs. It also implies that AMHS would be required to reduce variability of carrier delivery times.