US-12626882-B2 - Sample carrier for use in a charged particle microscope, and a method of using such a sample carrier in a charged particle microscope

US12626882B2US 12626882 B2US12626882 B2US 12626882B2US-12626882-B2

Abstract

The disclosure relates to a method of preparing a sample in a charged particle microscope. The method comprises the steps of providing a sample carrier having a mechanical support contour and a grid member connected thereto. The method comprises the step of connecting said sample carrier to a mechanical stage device of the charged particle microscope. Additionally, the method comprises the step of providing a sample, for example a chunk-shaped or lamella-shaped sample and connecting said sample to the grid member of the sample carrier. The method allows, in an embodiment, easy and reliable transfer of a sample between a bulk sample and a sample carrier.

Inventors

František Vaške
Jakub Kuba

Assignees

FEI COMPANY

Dates

Publication Date: 20260512
Application Date: 20220330
Priority Date: 20210331

Claims (11)

1 . Method of preparing a sample in a focused ion beam microscope, comprising the steps of: providing a sample carrier having a mechanical support contour and a grid member connected thereto, the grid member is substatially planar, and the mechanical support contour completely encloses the grid member about a circumference of said planar grid member, and the mechanical support contour is ring-shaped; connecting said sample carrier to a grid stage of said charged particle microscope; and providing a bulk sample held by a bulk stage, wherein the bulk stae and the grid stage are mounted to a same base; using said foucsed ion beam for creating a sample in said bulk sample; and releasing said sample said bulk and transferring said sample to said smaple carrier using an elongate transport member, wherein said elongate transport member defines an angle with a plane defined by said sample carrier, and wherein said angle is kept substantially constant during at least a substantial part of transfer of said sample from said bulk sample to said sample carrier, and wherein the elongate transport member is temporarily attached to said sample; characterized by the step of connecting said sample to the grid member of the sample carrier in a condition wherein the mechanical support contour and the grid member are pre-connected to each other.
2 . Method according to claim 1 , comprising the step of connecting said sample to the grid member of the sample carrier in a condition wherein the sample carrier is connected to said mechanical stage device.
3 . Method according to claim 1 , wherein said grid member and said mechanical support contour are integrally formed.
4 . Method according to claim 1 , wherein translational movement is used for transferring said sample.
5 . Method according to claim 4 , wherein said translational movement is provided by means of relative movement between the elongated manipulator and a mechanical stage of said charged particle microscope.
6 . Method according to claim 1 , wherein said elongate transport member comprises a needle.
7 . Method according to claim 1 , wherein said method is performed under cryogenic conditions.
8 . Sample carrier for use in a method according to claim 1 , comprising: the mechanical support contour that is arranged to be connectable to the mechanical stage device of the focused ion beam microscope; and the grid member that is pre-connected to said mechanical support contour and arranged for holding the sample, said grid member being free from any sample in said pre-connected state, and said grid member being arranged for receiving said sample in an assembled state of said sample carrier.
9 . Sample carrier according to claim 8 , wherein said grid member comprises a halfmoon grid.
10 . Sample carrier according to claim 8 , comprising said sample, wherein said sample comprises a lamella or chunk sample.
11 . Sample carrier according to claim 8 , wherein said grid member and said mechanical support contour are integrally formed.

Description

FIELD OF THE INVENTION The present embodiments relate to a sample carrier for use in a charged particle microscope, and a method of using such a sample carrier in a charged particle microscope. The present embodiments further relate to devices and methods of sample preparation for imaging systems. More specifically, the present embodiments relate to a sample preparation stage having multiple degrees of freedom allowing for in situ sample preparation and imaging. BACKGROUND OF THE INVENTION Charged-particle microscopy is a well-known and increasingly important technique for imaging microscopic objects, particularly in the form of electron microscopy. Historically, the basic genus of electron microscope has undergone evolution into a number of well-known apparatus species, such as the Transmission Electron Microscope (TEM), Scanning Electron Microscope (SEM), and Scanning Transmission Electron Microscope (STEM), and also into various sub-species, such as so-called “dual-beam” apparatus (e.g. a FIB-SEM), which additionally employ a “machining” Focused Ion Beam (FIB), allowing supportive activities such as ion-beam milling or Ion-Beam-Induced Deposition (IBID), for example. Samples for electron microscope imaging require certain preparation for observation under transmitted light or electron radiation. For example, thin slices (or sections) of a sample are typically cut or milled from a bulk sample in a grid or tube. The cutting or milling can be performed by a focused ion beam (FIB) system, or within a dual beam system that includes both a FIB and an electron microscope. Examples of such dual beam systems include the Quanta 3D DualBeam systems from FEI Corporation (Hillsboro, OR, USA). However, after the thin slices are prepared using the FIB, the samples must then be transferred to a platform suitable for imaging. Microscopic imaging, such as scanning transmission electron microscope (STEM), can require positioning along multiple degrees of freedom in order to capture a proper image. Others have prepared stages for STEM imaging that have multiple degrees of freedom. For example, U.S. Pat. No. 7,474,419 describes a stage assembly for positioning a sample in the vicinity of a reference point. The stage assembly includes a sample table to which the sample can be mounted and a set of actuators arranged so as to effect translation of the sample table along directions substantially parallel to an X-axis perpendicular to a reference plane, a Y-axis parallel to the reference plane, and a Z-axis parallel to the reference plane. The X-axis, Y-axis and Z-axis are mutually orthogonal and passing through the reference point. In addition, U.S. Pat. No. 6,963,068 describes a manipulator that has a table that can be moved in five degrees of freedom, with three perpendicular translations and two rotations. However, techniques for manipulating samples for STEM or TEM analysis are more complex. These techniques can require manipulating samples for both FIB milling and carving and the later STEM analysis to be performed at specific, critical temperature to prevent ice crystal formation in the sample, or to prevent undesirable thawing of the sample between manipulations. Additionally, it is very difficult to place the lamella in the required orientation in the lamella support. In particular, the thin lamella needs to be (almost) in the same plane as the lamella support, to ensure that the lamella can be positioned correctly in the (S)TEM for further examination. Furthermore, the transfer of the lamella from the sample to said support may involve welding and de-welding operations, which can damage the sample portion, and can even lead to its loss. It is for example possible that the lamella falls off the needle, or off the support. Thus, what is needed is a system and method that allows for complex manipulations of samples for STEM or TEM imaging without requiring so much sample handling that the sample becomes destroyed. In US 2008/173813 A1 a manipulator for rotating and translating a sample holder is disclosed. Here, a sample holder having a grid on which a sample is placed is held by a manipulator comprising two members in the form of two tapering cylinders. US 2020/273659 A1 describes a sample holder for a charged particle microscope, comprising a holder body with a recess for releasably receiving a sample carrier with a sample therein. SUMMARY According to an aspect, a method of preparing a sample in a charged particle microscope is provided, as defined in claim 1. The method comprises the steps of providing a sample carrier having a mechanical support contour and a grid member connected thereto, and connecting said sample carrier to a mechanical stage device of said charged particle microscope. As defined herein, the method further comprises the steps of providing a sample, such as a lamella-shaped or chunk-shaped sample, and connecting said sample to the grid member of the sample carrier. The step of connecting said sample