In the semiconductor industry internal loading of process tools is done mainly automatically.
Silicon wafers are moved from cassettes to the process chamber by a handling robot.
The cassettes are kept in many cases in carrier boxes, which protect the cassettes from particles and dirt - so called SMIF boxes for
200mm wafers and FOUP boxes for 300mm wafers. The transportation of those boxes from stocker to process tools and between process equipment
has been arrange in some cases already in the past by rail guides transportation systems. These are expensive and not very flexible.
The latest development are automatic self guided vehicles, AGVs.
They are rather cheap and easy to install - you can just start with a single system and then add more AGVs over the time.
These AGVs are very flexible in use. They can carry cassettes, tranportation boxes or also reticles for lithographic processes.
The carry path in the factory can be programmed as necessary. The AGVs find their way with assistance of maps and automatic position recognition.
AGVs recognize obstacles and human beings, go around them or just stop in doubt. This way, operators and robots can work on the same floor in the same clean room. AGVs also recognize process tools, adjust their position based on marks, attached to the loading station of the equipment and place the cassettes or boxes or reticles exactly and with high precision onto the I/O station of the process tool. AGVs drive electrically. They re-load their battery automatically on a loading station when they are idle. Such transportation systems are used in many industries now already. In a semiconductor factory there are some special conditions though - AGVs have to move around under very clean conditions in a clean room.
