Process apparatus including differential pumping device and focused ion beam column

A process apparatus comprising:

• a differential pumping device including a head which faces a given area of a process surface of a substrate to be processed and has a plurality of annular grooves formed in a process surface-facing surface of the head which faces the process surface of the substrate, the annular grooves surrounding a center of the head, the head having an orifice which is formed inside an innermost one of the annular grooves and defines a processing space serving to achieve processing of the process surface, at least one of the annular grooves being connected to a vacuum pump to suck gas from the one of the annular grooves with the process surface-facing surface opposed to the process surface to create a high-level vacuum in the processing space;
• and
• a focused ion beam column which is arranged on an opposite side of the head to the process surface-facing surface and includes a chamber leading to the orifice to be communicable with the processing space, the focused ion beam column also including a focused ion beam optical system which is disposed in the chamber and works to emit a focused ion beam through the orifice,
• wherein a precursor gas supply is connected to the innermost one of the annular grooves to eject a precursor gas toward the process surface so that the precursor gas flows into the processing space along the process surface.