CONVEYING METHOD FOR SEMICONDUCTOR SUBSTRATE

PURPOSE:To improve the yield in checking any sticking of particles by repeating an evacuation and a nitrogen purge just before the conveyance of a processed semiconductor substrate. CONSTITUTION:Three valves P1 to P3 for nitrogen gas incoming via a filter 5 are set up in a loading chamber 1, an etching chamber 2 and an unloading chamber 3 of a dry etching unit and four gate valves G1 to G4 among respective chambers, respectively. Those of loading, etching and unloading chambers 1, 2, 3 are forced into vacuum in advance and on standby. Next, the etching unit is made into an operating condition, opening the valve P1, and the loading chamber 1 is subjected to a nitrogen purge into an atmospheric state. Then, the valve P1 is closed and the valve G1 is opened or closed and, after this valve G1 is closed, a mechanical booster pump MB-2 is operated into the degree of specified vacuum. Successively, the gate valve G2 is opened or closed and thereby the etching chamber 2 is also forced into the same degree of vacuum while particles stuck to the valves are exhausted and, after similar operations are repeated several times in succession, vacuum conveyance for a semiconductor substrate is carried out.