Charged particle beam system having multiple user-selectable operating modes

A method of operating a charged particle beam system in multiple modes:

• directing a charged particle beam from a charged particle beam source toward a work piece surface to mill a pattern on the work piece surface, the source of the charged particle beam system operating in accordance with a first set of source operating parameters, the charged particle beam having a first beam current and a first beam spot size;
• changing at least one source operating parameters;
• and
• operating the charged particle beam system using the changed source operating parameters to direct the charged particle beam from a charged particle beam source toward a work piece surface to form an image of the results of milling the pattern, the ions being used to mill the pattern and the ions being used to form the image being of the same species.

A charged particle beam system, comprising:

• a plasma chamber for containing a plasma gas at a plasma chamber gas pressure;
• an extraction electrode to which a voltage can be applied for extracting ions or electrons from the plasma chamber;
• a power supply for supplying power to the plasma chamber to maintain a plasma in the plasma chamber;
• a gas supply for supplying the plasma gas to the plasma chamber;
• a focusing column comprising a plurality of lenses for focusing ions or electrons extracted from the plasma chamber;
• and
• a computer readable memory storing a set of operating parameters for each of multiple operating modes, the operating parameters including one or more of:
• the plasma chamber gas pressure;
• the power supplied to the plasma;
• the voltage supplied to the extraction electrode,
• a controller programmed to selectively switch the charged particle beam system between operating modes for the same ion species, the controller causing at least one of the operating parameters of the charged particle beam system to be set in accordance with the stored operating parameters for the selected mode;
• and
• one or more beam-limiting apertures and an aperture positioning actuator, the controller programmed to selectively position a beam-limiting aperture corresponding to the selected operating mode in the path of the charged particle beam depending on the beam current required for the selected operating mode.