Abstract:
Transducer (10) apparatus and method combining both an absolute pressure sensor (20) for sensing absolute pressure in the load lock chamber (60) and a differential pressure sensor (30) for sensing a pressure difference between ambient atmospheric pressure and pressure in a load lock chamber (60) and provides control signals for opening an interior door (62) from the load lock chamber (60) into a vacuum processing chamber (70) and for opening an exterior door (64) between ambient atmosphere and the load lock chamber (60). The transducer (10) can also produce signals to control transition from slow to fast vacuum pump-down of load lock chamber (60) pressure at a predetermined pressure set point.
Abstract:
A method and apparatus integrates differential pressure measurements and absolute pressure measurements to provide virtual absolute pressure measurements over a wide range of pressures on a single integrated scale. To achieve the foregoing objects the method and apparatus for measuring absolute pressure in a chamber (see figure) includes determining a correlation factor between absolute and differential pressure measurements taken simultaneously at a pressure where the absolute pressure in the chamber can be measured accurately, and adjusting differential pressure measurements with the correlation factor to provide virtual absolute prenure measurements.
Abstract:
A method and apparatus integrates differential pressure measurements and absolute pressure measurements to provide a continuous absolute pressure profile over a wide range of pressures on a single integrated scale. The absolute pressure measurements and differential pressure measurements are obtained, and a correlation factor between the absolute pressure measurements and the differential pressure measurements is determined. The correlation factor is used to normalize the differential pressure measurements to virtual absolute pressure values on a common absolute pressure scale with the absolute pressure measurements. An absolute pressure profile over a wide pressure range includes the absolute pressure measurements in a portion of the range where the absolute pressure measurements are accurate, and it includes the virtual absolute pressure values in another portion of the range where the differential pressure measurements are accurate.
Abstract:
A pirani absolute pressure sensor for sensing absolute pressure in a load lock in a range from 100 to 10 -4 torr and a differential pressure sensor for sensing a pressure difference between ambient atmospheric pressure and pressure in the load lock chamber are combined together in a module with a manifold and common circuit components to provide a pressure transducer that is capable of producing not only analog output for absolute pressure measurements, but also control signals at settable absolute and differential pressure values for opening interior and exterior doors of a load lock used to shuttle wafers and other devices into and out of a vacuum processing chamber. The transducer can also produce signals to control transition from slow to fast vacuum pumping of the load lock chamber at a settable threshold pressure.
Abstract:
A method and apparatus integrates differential pressure measurements and absolute pressure measurements to provide a continuous absolute pressure profile over a wide range of pressures on a single integrated scale. The absolute pressure measurements and differential pressure measurements are obtained, and a correlation factor between the absolute pressure measurements and the differential pressure measurements is determined. The correlation factor is used to normalize the differential pressure measurements to virtual absolute pressure values on a common absolute pressure scale with the absolute pressure measurements. An absolute pressure profile over a wide pressure range includes the absolute pressure measurements in a portion of the range where the absolute pressure measurements are accurate, and it includes the virtual absolute pressure values in another portion of the range where the differential pressure measurements are accurate.