US Patent 7553773 Pressure control method and processing device

First and second pressure sensors 132 and 134 that perform pressure detection over different pressure detection ranges from each other detect the pressure within a process chamber 102 of an etching device 100. A pressure controller 144 selects optimal pressure data in correspondence to the pressure inside the process chamber from the pressure data provided by the first and second pressure sensors 132 and 134. It also analyzes the selected pressure data at a resolution selected in correspondence to the pressure inside the process chamber 102 and thus obtains pressure data achieving a predetermined data density. The pressure controller 134 controls a pressure control valve 130 so as to ensure that the pressure data match preset pressure data.