Efficiency of risk reduction by installation of seismic isolation system for vertical furnace

In semiconductor production process, a role of vertical thermal processing equipment, hereinafter called “Vertical furnace”, is very important. Vertical furnaces plays a key role in a plurality of front-end wafer processes including CVD, film formation, diffusion and anneal etc. For this reason, minimizing the outage period lead risk modification in production line against emergencies like a disaster, and it is important as a measure in business continuity plan (BCP) to resume operation quickly. However, vertical furnaces should not to be strong against earthquake. It was reported that vertical furnace tended to have problems like silica tube damage, position gap or dropping of wafer under processing when medium-scale earthquake occurred because of its high and thin shape, delicate constituent material and high positioning of wafers under processing even if vertical furnace had been fixed securely. As measures for earthquake, structural reinforcement of manufacturing equipment and addition of the operation of the saving mechanism by the conjunction of the earthquake warning system¹⁾, etc. is carried out. However, it is not easy to implement measures in manufacturing equipment against earthquake efficiently without effect to performance of manufacturing equipment. We developed seismic isolation system for vertical furnace to reduce the damage of manufacturing equipment caused by earthquake without small effect on performance of the equipment and installed them in the fabrication plant under operating. In this report, firstly, the mechanism of seismic isolation system and verification by shaking table experiment and validity of simulation technology, which are derived from our previous research^2–4), are introduced. Secondly, effect of utility piping connected to vertical furnace is described. And lastly, risk reduction of vertical furnace by installation of seismic isolation system against the 2011 off the Pacific coast of Tohoku Earthquake is reported.