Patent ID: 8880210

Claim:
A method of controlling a process chamber having a processing volume, comprising: predetermining a relationship between pressure in the processing volume and a position of an exhaust valve disposed between the processing volume and an exhaust system as a function of a process parameter; setting the process chamber to a first state having a first pressure in the processing volume and a first value of the process parameter, wherein the exhaust valve is set to a first position based on the predetermined relationship to produce the first pressure in the processing volume at the first value; determining a pressure control profile to control the pressure in the processing volume as the process chamber is changed to a second state having a second pressure and a second value of the process parameter from the first state, wherein the pressure control profile is determined from a model based control algorithm that uses the first pressure, the second pressure, the first value, the second value, and the first position as input parameters; and applying the pressure control profile to control the pressure in the processing volume by varying the position of the exhaust valve while changing the process chamber to the second state from the first state.