Vacuum chuck pressure control system

A substrate processing apparatus, comprising:

• a process chamber which defines a process volume;
• a vacuum chuck support for vacuum supporting a substrate disposed within the process volume;
• a variable flow valve in fluid communication with the vacuum chuck, wherein the variable flow valve is disposed on a fluid flow path upstream from the vacuum chuck;
• a pressure controller comprising a pressure detector and a flow rate detector, the pressure controller disposed in the fluid flow path upstream from the vacuum chuck and located on the fluid flow path between the variable flow valve and the vacuum chuck, wherein the pressure controller being disposed upstream from the vacuum chuck prevents the pressure controller from being exposed to fluid flow from a control volume of the vacuum chuck along the fluid flow path;
• a flow restrictor in fluid communication with the vacuum chuck, a control volume of the vacuum chuck, and the variable flow valve during vacuum chucking, wherein the flow restrictor is disposed on the fluid flow path downstream from the vacuum chuck and provides a constant impedance to flow from the control volume;
• a second valve disposed downstream of the flow restrictor;
• and
• a vacuum pump disposed downstream of the second valve, the vacuum pump in fluid communication with the process volume through a first conduit and the control volume of the vacuum chuck through a second conduit.