Process apparatus with on-the-fly substrate centering

A substrate processing apparatus comprising:

• a frame defining a chamber with a substrate transport opening and a substrate transfer plane defined therein;
• a valve mounted to the frame and being configured to seal an atmosphere of the chamber when closed, the valve having a closure movably disposed to open and close the substrate transport opening;
• and
• at least one substrate alignment element disposed proximate a seal edge of the closure and oriented and positioned by the closure so that the at least one substrate alignment element interacts with substrates passing through the substrate transport opening proximate the seal edge located on the substrate transfer plane so that the substrate alignment element registers a substrate centering alignment characteristic determinative of substrate center alignment relative to a substrate holding station, of the substrates passing through the substrate transport opening on the substrate transfer plane, the substrate holding station being different than the valve.