Three dimensional imaging of microelectronic devices using a crossbeam FIB

These experiments were performed using a Carl Zeiss 1540 crossbeam instrument that permits SEM imaging during ion milling. The FIB beam consists of 30 KV Ga ions with currents ranging from several nanoamperes down to several picoamperes. The Schottky source electron gun was run in the high current mode at 1 and 5 KV to provide an electron beam current of about 2nA. Much of the surrounding material is removed to allow for better viewing and expose the faced used to start the milling. The FIB was then set to mill through the entire region with the SEM set to capture a secondary electron image of the freshly exposed surface every 10 seconds. After these images are created they can be orientated and manipulated to provide a view of any part of the volume including slicing the volume from any arbitrary direction. After the image is collected the sample is reoriented back to the milling position. This process is repeated until the region of interest is fully eroded.