Focused charged particle beam apparatus

A focused charged particle beam apparatus comprising:

• a support which supports a substrate to be processed;
• and
• a focused charged particle beam column which is equipped with a differential pumping device which is configured to be movable to a location facing a given area of a process target surface of the substrate, wherein
• the support bears only a Periphery of the substrate while keeping the substrate horizontal,
• a positive pressure chamber is disposed below the substrate borne by the support, the positive pressure chamber working to exert a positive pressure on a whole of the process target area of the substrate to cancel deflection of the substrate arising from its own weight, and
• a local depressurizing mechanism is arranged in the positive pressure chamber and placed out of contact with the substrate, the local depressurizing mechanism working to exert a negative pressure on a lower surface of the substrate to cancel a suction force created by the differential pumping device, the local depressurizing mechanism being movable relative to the substrate following movement of the differential pumping device while facing the differential pumping device through the substrate,
• wherein a first floating pad is arranged so as to surround an outer periphery of the differential pumping device and works to eject gas to the process target surface, and a second float pad is disposed so as to surround an outer periphery of the local depressurizing mechanism and works to eject gas to the lower surface of the substrate.