Experimental study on seismic vibration control of stockers in wafer and LCD panel fabs

Automated stocker system is widely used in semiconductor and liquid crystal display (LCD) industries for handling storage of valuable wafers or glass panels. Massive front opening unified pods (foups) containing wafers, cassettes storing panels, are placed shelf stockers during manufacturing. Although several preventative measures have been taken, the past earthquakes, substantial financial loss from were reported, one main causes was attributed to collision foups shake off shelfs. This paper proposes a methodology incorporating viscous fluid dampers into stokers mitigate their seismic response. Unlike conventionally done buildings where between adjacent stories, it proposed install ceiling top stocker. Such configuration utilizes large velocity at under vibration, resulting smaller damper size, enables leverage mechanism that requires force resist stocker’s vibration. Both table tests simulation full-scale realistic earthquakes conducted. Results indicate both displacement acceleration responses can be significantly reduced, dynamic response excitations well predicted.