Semiconductor fabricating apparatus, method for modifying positional displacement of a wafer in a wafer cassette within the semiconductor fabricating apparatus and method for transferring the wafer cassette

A semiconductor fabricating apparatus for use with a plurality of wafer cassettes, each of which can carry at least one wafer, said apparatus comprising:

• a reaction furnace for treatment of a plurality of wafers;
• a holder for holding said plurality of wafers, said holder capable of being loaded into said reaction furnace;
• a storage area having a plurality of wafer cassette shelves, which are capable of storing at least one wafer cassette;
• a wafer transfer device for transferring at least one wafer between said holder and said storage area such that said wafer is in a substantially horizontal direction;
• and
• a cassette transfer unit capable of receiving at least one wafer cassette from outside said apparatus;
• and
• a cassette transfer device capable of transferring at least one wafer cassette between said cassette transfer unit and said storage area,
• wherein said cassette transfer device is capable of situating at least one wafer cassette on one of said plurality of wafer cassette shelves in the storage area such that the wafers therein are substantially horizontal, and situating at least one other wafer cassette on another one of said plurality of wafer cassette shelves in the storage area excluding said cassette transfer unit such that the wafers therein are substantially vertical so that clean air is permitted to flow past the vertical wafers.