Abstract: In a chemical vapor deposition system, susceptors are supported by a pair of turntables which are disposed in a vertical and parallel arrangement. A plurality of wafers to be processed are arranged circumferentially on opposing surfaces of the susceptors, and heater units are arranged behind the turntables. Because the wall surfaces exposed to the material gas are mostly covered by the wafers to be processed, any wasteful deposition of material on the chamber surfaces can be avoided. Thus, the need to clean the surface of the chamber wall is minimized. Such material deposition is not only wasteful but also could become a source of contamination as such deposition tends to peel off.

Abstract: In a chemical vapor deposition system, a pair of turntables are vertically disposed opposite to each other, and a plurality of wafers to be processed are arranged circumferentially on opposing surfaces of the turntables. Heater units are arranged behind the turntables, each of the heater units comprising a plurality of concentric grooves defined in a surface of a base behind the corresponding one of the turntables, a heating element received in each of the grooves, a cover plate placed over the grooves so as to seal the interior of the grooves from the exterior of the grooves, and a conduit connected to a vacuum pump for maintaining a higher level of vacuum in the grooves than outside cover plate. Thus, the interior of the grooves is effectively sealed, and intrusion of contaminants into the heater unit can be avoided.

Abstract: In order to separate and remove a dangerous substance such as yellow phosphorus from exhaust gas generated in a semiconductor fabricating process by chemical vapor deposition, the exhaust gas is bathed in operating oil of a cooled oil tank of an oil-sealed rotary vacuum pump so that molecules of the yellow phosphorus or the like are caught by the cooled operating oil so as to be enveloped in the operating oil. Thus, a mixture operating oil of the substance and the operating oil is generated in the form of colloid. The mixture operating oil is passed through an oil filter of a filtration device so that the substance such as yellow phosphorus is precipitated by the filter and then the substance is removed. Meanwhile, the operating oil as a filtrate from which the substance has been filtered is cooled by an oil-temperature controller, and then returned to the oil-sealed rotary vacuum pump.