Mks Instruments, Inc.

Stacy Wade

Youfan Gu

Garry Holcomb

Neil T Peacock

James M Mueller

James Stafford

A pirani absolute pressure sensor for sensing absolute pressure in a load lock in a range from 100 to 10torr 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.

Method of using a combination differential and absolute pressure transducer for controlling a load lock

A method operating a hot cathode ionization pressure gauge during electron bombardment and resistance degas operations by controlling the degas power levels as a function of the gauge pressure. In one embodiment, the degas power level is increased and decreased in steps, and the gauge pressure monitored following each increase and decrease. In another embodiment the rate of change in the gauge pressure is monitored while the degas power level is increased. If it is determined from the monitored rate of change that the gauge pressure may exceed the upper limit, the degas power increases can be stopped or the degas power decreased. These operation are continued until predetermined final degas conditions are met. A display can be activated following the successful completion of the degas operation.

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Boulder, CO, United States of America

Stacy Wade