A liquid filter apparatus for gas/solid separation includes a housing with a filter chamber, a semiconductor process gas inlet, and a process gas outlet. The filter chamber forms a liquid reservoir, and the semiconductor process gas inlet and the process gas outlet are in communication with the filter chamber. The housing further includes a filter liquid inlet and a filter liquid outlet, which are in communication with the liquid reservoir for delivering and removing filter fluid, respectively, to and from the liquid reservoir.

A thin-film forming device forms a thin film on a strip-shaped substrate by subjecting the strip-shaped substrate to a surface treatment while conveying the strip-shaped substrate in a state of being laid along an outer peripheral face of a main roll. The thin-film forming device comprises: a main roll chamber accommodating the main roll; a plurality of film formation chambers arranged in a peripheral direction of the main roll, the film formation chambers having partitions disposed radially outward of the main roll; and a main roll cover covering the outer peripheral face of the main roll over which the strip-shaped substrate travels, the main roll cover being provided to the partitions, the main roll cover having a film formation chamber communication component that communicates with the film formation chambers. A pressure in an interior of the main roll cover defined between the main roll cover and the outer peripheral face of the main roll is set to be higher than a pressure in the film formation chambers.

Silicon deposited by CVD and/or silico dust is removed from a polycrystalline silicon deposition reactor component by abrasion with silicon-containing particles in a gas stream.