The world´s first automated reticle handling system using OHT

The automation of wafer carrier transport in modern semiconductor fabs has progressed, with some 300 mm wafer fabs which are regarded as almost full automation. At the same time, a requirement for the automated reticle transfer system becomes higher in the photolithography step. Recent multiproduct fabs require more frequent reticle exchanges, while it´s required that those reticle exchanges are performed more quickly than ever. To solve these new problems, we developed and introduced the first automated reticle handling system using overhead hoist transport (OHT) in the world. The new OHT system drastically improved the reticle transport time by one-eighth comparing with previous system, AGV (Automatic Guided Vehicle) based system in our fab. Moreover, the reticle OHT system enabled us to reduce construction costs and increase photolithography equipment throughput.