Abstract: A method of preparing a sample for transmission electron microscopy (TEM) analysis is provided. The method comprises cleaning the sample to remove a redeposition layer, imaging the cleaned sample and identifying a location of a region of interest within the sample, and removing material from the sample, based on the identified location of the region of interest within the sample. Advantageously, the sample thinning step is performed based on a detected location of a region of interest. This thinning step involves removal of uneven surfaces (the “lamella roof”) and thinning the remaining bulk substrate to remove redundant material, so that the silicon substrate volume between the surface of the sample and the region of interest has a defined thickness.

Abstract: Lamellae with thin regions for TEM of regions of interest include oppositely situated S-shaped cut faces that define a waist region. In some examples, the waist has a thickness of less than 25 nm and defines a double tapered region of height of between 400 nm and 800 nm that is suitable for TEM. A portion of the lamella at the top surface can comprising a metallic or other coating than serves to support the lamella.

Abstract: Wedged lamella can be prepared by milling multiple sample slices from at least one side of a sample. The milling is monitored based on an SEM image acquired after removing one or more of the sample slices. The milling may be terminated responsive to an estimated distance between a first structure and a second structure along the height of the milled sample not greater than a threshold distance.

Abstract: Methods and apparatus are disclosed for determining a distance from a cut face of an active sample to a target plane, using data acquired from a reference sample. The active and reference samples have congruent structure, allowing reference data to be used as an index. An SEM image of the cut face is compared with the reference data to determine position within the active sample, and thereby the remaining distance to the target plane. The technique can be applied repeatedly between phases of ion beam milling until an endpoint at the target plane is reached. Consistent, accurate endpointing is achieved. The technique is suitable for preparing 5-100 nm thick lamella for TEM analysis of electronic circuits and can be used in a wide range of applications. Variations are disclosed.

Abstract: Apparatuses and methods for aligning lamella to charged particle beams based on a volume reconstruction are disclosed herein. An example method at least includes forming a reconstructed volume of a portion of a sample, the sample including a plurality of structures, and the reconstructed volume including a portion of the plurality of structures, performing, over a range of angles, a mathematical transform on each plane of a plurality of planes of the reconstructed volume, and based on the mathematical transform on each plane of the plurality of planes, determining a target orientation of the sample within the range of angles, wherein the target orientation aligns the plurality of structures parallel to an optical axis of a charged particle beam.

Abstract: Apparatuses and methods for aligning lamella to charged particle beams based on a volume reconstruction are disclosed herein. An example method at least includes forming a reconstructed volume of a portion of a sample, the sample including a plurality of structures, and the reconstructed volume including a portion of the plurality of structures, performing, over a range of angles, a mathematical transform on each plane of a plurality of planes of the reconstructed volume, and based on the mathematical transform on each plane of the plurality of planes, determining a target orientation of the sample within the range of angles, wherein the target orientation aligns the plurality of structures parallel to an optical axis of a charged particle beam.

Abstract: A substrate is alignable for ion beam milling or other inspection or processing by obtaining an electron channeling pattern (ECP) or other electron beam backscatter pattern from the substrate based on electron beam backscatter from the substrate. The ECP is a function of substrate crystal orientation and tilt angles associated with ECP pattern values at or near a maximum, minimum, or midpoint are used to determine substrate tilt. Such tilt is then compensated or eliminated using a tilt stage coupled the substrate, or by adjusting an ion beam axis. In typical examples, circuit substrate “chunks” are aligned for ion beam milling to reveal circuit features for evaluation of circuit processing.

Abstract: A substrate is alignable for ion beam milling or other inspection or processing by obtaining an electron channeling pattern (ECP) or other electron beam backscatter pattern from the substrate based on electron beam backscatter from the substrate. The ECP is a function of substrate crystal orientation and tilt angles associated with ECP pattern values at or near a maximum, minimum, or midpoint are used to determine substrate tilt. Such tilt is then compensated or eliminated using a tilt stage coupled the substrate, or by adjusting an ion beam axis. In typical examples, circuit substrate “chunks” are aligned for ion beam milling to reveal circuit features for evaluation of circuit processing.