Abstract: A backfill prevention system for a gas flow conduit, comprising a gas flow monitor circuit which measures the rate and direction of gas flow through a gas flow conduit and converts the measured data into a voltage signal. A valve control circuit operably connected to a valve or valves in the gas flow conduit receives the voltage signal from the gas flow monitor circuit and closes the valve or valves in the event that the voltage signal indicates backflow of a gas through the gas flow conduit. The valve control conduit may further be provided with a first light emitting diode (LED) which is illuminated during normal flow of the gas through the conduit, and a second LED which is illuminated in the event of gas backflow through the conduit. The system is typically used in conjunction with a mass flow controller in the conduit.

Abstract: A microchip fabrication chamber has a pedestal adapted to retain a wafer during processing steps conducted within the chamber. A lift mechanism including a plurality of lift mechanism pins engages and disengages a wafer to the pedestal. A sensor associated with the tip of at least one of the lift mechanism pins detects the presence of the wafer.

Abstract: A pressure switch device for controlling gas without calibration of pressure in a vacuum system is disclosed. The pressure switch device comprises an isolation valve for controlling gas flow between a chamber and a pump, a pressure balance switch bypassing said isolation valve and detecting a pressure difference between the chamber and the pump, and a control line used by said pressure balance switch to control said isolation valve, wherein said pressure balance switch open said isolation valve whenever the pressure difference between the chamber and the pump is larger than a predetermined value.

Abstract: A backfill prevention system for a gas flow conduit, comprising a gas flow monitor circuit which measures the rate and direction of gas flow through a gas flow conduit and converts the measured data into a voltage signal. A valve control circuit operably connected to a valve or valves in the gas flow conduit receives the voltage signal from the gas flow monitor circuit and closes the valve or valves in the event that the voltage signal indicates backflow of a gas through the gas flow conduit. The valve control conduit may further be provided with a first light emitting diode (LED) which is illuminated during normal flow of the gas through the conduit, and a second LED which is illuminated in the event of gas backflow through the conduit. The system is typically used in conjunction with a mass flow controller in the conduit.

Abstract: A composite shadow ring that is constructed of an upper ring and a lower ring assembled together by a plurality of dowel pins and a method for using the ring. The upper ring and the lower ring each has a predetermined outside diameter that is substantially the same, a planar top surface and a planer bottom surface parallel to the planar top surface. Each of the planar bottom surface of the upper ring and the planar top surface of the lower ring has at least two blind holes formed therein. A plurality of dowel pins are used to frictionally engage the at least two blind holes in the upper ring and the at least two blind holes in the lower ring.

Abstract: A cover or housing which spans an output port of a first station and an input port of a second station in a manufacturing facility, for example, and covers or houses a conveyor extending between the stations for conveying articles from the first station to the second station. A source of nitrogen gas or clean dry air is provided in communication with the housing interior, and at least one exhaust fan is provided on the housing. As articles are conveyed from the first station to the second station, nitrogen gas or clean dry air is blown into the housing and drawn therefrom through the exhaust fan or fans, such that the flowing gas or air removes particles from the articles as they are carried to the second station.

Abstract: A microchip fabrication chamber has a pedestal adapted to retain a wafer during processing steps conducted within the chamber. A lift mechanism including a plurality of lift mechanism pins engages and disengages a wafer to the pedestal. A sensor associated with the tip of at least one of the lift mechanism pins detects the presence of the wafer.