Patent ID: 9595420
Date: 2017-03-14
CPC Classifications: G01N,H01J

Claim:
1. A lamella preparation method of preparing a lamella having a thickness of 100 nm or smaller by performing processing of a sample using a focused ion beam, the lamella preparation method comprising: irradiating a focused ion beam onto a sample to form a lamella having an upper side having a thickness of 100 nm or smaller and a lower side having a thickness larger than that of the upper side; irradiating an electron beam onto the lamella to form an observation image; setting a first measurement region on the upper side of the lamella and a second measurement region on the lower side of the lamella in the observation image, the first and second measurement regions being set at locations where the lamella is thin enough to transmit therethrough the electron beam; irradiating the electron beam onto the first measurement region and the second measurement region and detecting charged particles generated therefrom; calculating a slant angle of the lamella of one degree or smaller based on (a) a difference between the thickness of the first measurement region, which is estimated from a detected amount of the charged particles generated from the first measurement region, and the thickness of the second measurement region, which is estimated from a detected amount of the charged particles generated from the second measurement region, and (b) the distance between the first measurement region and the second measurement region; slanting the lamella with respect to the focused ion beam by the slant angle so that a first surface of the lamella is parallel with an irradiation axis of the focused ion beam; and irradiating the focused ion beam onto a second surface of the lamella, which is opposite to the first surface, to perform finish processing to uniformize the thickness of the lamella to a value of 100 nm or smaller.