Abstract: A low pressure chemical vapor deposition apparatus is provided for removing particulate matter. The apparatus includes a bell jar, a quartz tube installed in the bell jar, a slotted quartz boat installed in the quartz tube and for holding wafers which are to be coated with film. The apparatus further includes a gas line for introducing a reactant gas into the chamber within the quartz tube, where the quartz boat is located, a gas inlet made of quartz, an MFC, a valve 10 a three-zone furnace for heating the quartz tube to a reaction temperature, a pump 4 for pumping out air and reactant gas from the chamber within the quartz tube, a door plate for placing the slotted quartz boat in the chamber a power source device for causing an electric current to charge contacts with a positive or negative bias which are provided on the door plate, and a main controller for operating the power source device.