Patent ID: 9184025
Filing Date: 2015-11-10
Classification: G01N,H01J

Abstract:
1. An apparatus, comprising: a transmission electron microscope or scanning transmission electron microscope to obtain contrast information for a sample; a focused ion beam column to mill the sample to a desired thickness; a computer-readable memory storing calibration data; and a controller to control the focused ion beam column to mill the sample to the desired thickness, wherein said stored calibration data comprises data indicative of a dark field signal crossover point, the dark field signal crossover point comprising an intersection of a contrast versus thickness curve for a first material and a contrast versus thickness curve for a second material at a desired electron beam voltage, the contrast versus thickness curves being derived from a calibration sample of the same mixture of the first material and the second material as the sample to be thinned; and the controller is configured to cause the focused ion beam column to discontinue milling when the contrast information indicates contrast values for the first and second material match the dark field crossover point for the calibration sample at the desired thickness.