A fully integrated photolithography workcell

A photolithography workcell that allows all operations on a wafer lot, from resist coat through to inspection, to be executed by a single operator is described. The workcells are based on 5× steppers and in-line coat and develop tracks. Operation of the cell is heavily based on automation software, with a single operator-interface terminal to all subequipment and process control databases. A key benefit of the workcell is the environment in which a single operator has ownership for all aspects of the photolithographic process. Feedback on process quality is available by inspection 12 min after a lot has started. Key results from the workcell are: (1) rework rate reduced from 11% to less than 2%; (2) feedback time on a lot reduced from 8 h to 15 min; and (3) average active time of work-in-progress in the photo area reduced from 24 h to 8 h