Patent ID: 8735847

Claim:
A method of operating a focused ion beam device having a gas field ion source and at least a first electrostatic lens, the first electrostatic lens including, in beam direction, a first electrode, a second electrode and a third electrode, and at least a second electrostatic lens, the second electrostatic lens including, in beam direction, a first electrode, a second electrode, and a third electrode, the method comprising: emitting an ion beam from a gas field ion source; providing an ion beam energy in an ion beam column which is higher than a final beam energy, wherein the ion beam energy is 5 keV to 12 keV; first accelerating the ion beam to a higher energy within the first electrostatic lens between the first electrode and the second electrode by providing the second electrode to a higher potential, and thereafter first decelerating the ion beam within the first electrostatic lens between the second electrode and the third electrode; after the first decelerating the ion beam, second accelerating the ion beam within the second electrostatic lens between the first electrode and the second electrode by providing the second electrode to a higher potential; after the second accelerating the ion beam, second decelerating the ion beam within the at least second electrostatic lens for providing the final beam energy on impingement of the ion beam on a specimen of 1 keV to 4 keV; and imaging the specimen using the ion beam.