Passive protective strategy for ultra-precision dual-stage

In order to improve the throughput of lithography machine, a new type of lithography machine began to adopt double wafer stages which make the exposure and measurement work simultaneously. But at the same time, this structure also increases the risk greatly, the wafer stage collision for instance. Therefore, a corresponding safety protection system is necessary to protect the whole double wafer stages system and to improve the throughput on the premise of safety. In this paper, a passive safety protection strategy for double-stages lithography machine is proposed based on analysis of its working conditions. The design principle of safety needle is elaborated, and then needle distribution is determined correspondingly. The simulation results show that, the proposed passive protection method carried out by safety needles could avoid damages of sensitive apparatus.