Patent ID: 7438534

Claim:
An apparatus for exhausting gas from an exhaust port of a vacuum chamber to maintain a process pressure in the chamber, comprising: a pressure sensor for measuring pressure in the vacuum chamber; a throttle valve in communication with the exhaust port of the vacuum chamber for regulating flow from the exhaust port; a high-vacuum pump having a pump inlet and a backing port, the pump inlet communicating with the throttle valve; a backing valve in communication with the pump backing port for regulating flow from the backing port; at least one controller for regulating opening sizes of the throttle valve and the backing valve based on a measurement from the pressure sensor, to maintain the process pressure in the chamber; wherein the at least one controller comprises: a tool controller connected to the pressure sensor for sequencing the process chamber through at least one process flow rate and process pressure; a throttle valve controller connected to the throttle valve for controlling an opening of the throttle valve; a backing valve controller connected to the backing valve for controlling an opening of the backing valve; and a processor in communication with the tool controller, the throttle valve controller and the backing valve controller, the processor having storage media for storing computer readable instructions executable by the processor for regulating opening sizes of the throttle valve and the backing valve based on a measurement from the pressure sensor, to maintain the at least one process flow rate and process pressure in the chamber.