A new FIB fabrication method for micropillar specimens for three-dimensional observation using scanning transmission electron microscopy

A new method to prepare micropillar specimens with a high aspect ratio that is suitable for three-dimensional scanning transmission electron microscopy (3D-STEM) was developed. The key features of the micropillar fabrication are: first, microsampling to extract a small piece including the structure of interest in an IC chip, and second, an ion-beam with an incident direction of 60degrees to the pillar's axis that enables the parallel sidewalls of the pillar to be produced with a high aspect ratio. A memory-cell structure (length: 6 mum; width: 300 x 500 nm) was fabricated in the micropillar and observed from various directions with a 3D-STEM. A planiform capacitor covered with granular surfaces and a solid crossing gate and metal lines was successfully observed three-dimensionally at a resolution of approximately 5 nm.