Patent ID: 7279067

Claim:
A port structure for loading and unloading a substrate to be processed into and from a semiconductor processing system, wherein an inside of the system is set to have a positive pressure compared to an outside thereof by a gas supply, the port structure comprising: a bulkhead for partitioning the inside and the outside of the system and having a port for passing therethrough the substrate to be processed; a door for opening and closing the port; a table disposed outside the system to face the port, wherein the table is provided with a mount region for mounting thereon an open cassette accommodating therein a plurality of substrates to be processed in multi-levels; a hood rotatably disposed between a closed position and an open position with respect to the table, wherein the hood at the closed position forms, together with the bulkhead and the table, a closed space surrounding the mount region and the port, the closed space having a size to accommodate therein the cassette mounted on the mount region, and the hood at the open position exposes the mount region; a driving unit for rotating the hood; first ventholes formed through at least one of the bulkhead and the door so as to introduce the gas from the inside of the system into the closed space; and second ventholes formed through the table so as to discharge the gas out of the closed space.