Patent ID: 8051870

Claim:
A low pressure processing system comprising a reaction vessel, an exhaust passage connected to the reaction vessel, and a gate valve provided in the exhaust passage, said system being configured to process a substrate contained in the reaction vessel by a predetermined treatment by supplying a process gas into an interior of the reaction vessel while maintaining an atmosphere of a reduced pressure in the interior of the reaction vessel by evacuating the same through the exhaust passage, wherein: the gate valve has a valving element and a valve seat; the valve seat has a first annular surface and the valving element has a second annular surface opposing the first annular surface, the first or second annular surface being provided thereon with a sealing member; the gate valve hermetically closes the exhaust passage by pressing the second annular surface of the valving element against the first annular surface of the valve seat with the sealing member being interposed between the first and second annular surfaces; the gate valve also regulates pressure in the reaction vessel by adjusting a gap between the valving element and the valve seat; the gate valve is provided therein with a plurality of first purge gas supply ports circumferentially arrayed beside the first annular surface of the valve seat to jet a purge gas along the first annular surface of the valve seat; and the valving element is provided therein with a plurality of second purge gas supply ports circumferentially arrayed beside the second annular surface of the valving element to jet a purge gas along the second annular surface of the valving element, the low pressure processing system further comprising: at least one purge gas valve provided to supply and stop supplying the purge gas from the first and second purge gas supply ports; and a controller configured to control the purge gas valve so that the purge gas valve is opened to supply the purge gas when the interior of the reaction vessel is supplied with the process gas.