Method for changing the spatial orientation of a micro-sample in a microscope system, and computer program product
11355310 · 2022-06-07
Assignee
Inventors
Cpc classification
G01N23/20083
PHYSICS
H01J37/26
ELECTRICITY
H01J37/3056
ELECTRICITY
G01N1/286
PHYSICS
H01J2237/31745
ELECTRICITY
G01N2223/045
PHYSICS
International classification
Abstract
A method is carried out with the aid of a particle beam microscope which includes a particle beam column for producing a beam of charged particles, the particle beam column having an optical axis. Furthermore, the particle beam microscope includes a holding device for holding the extracted micro-sample. The method includes holding the extracted micro-sample and an adjacent hinge element via the holding device. The micro-sample adopts a first spatial orientation relative to the optical axis. The method also includes producing a bending edge in the hinge element by way of irradiation with a beam of charged particles such that the adjacent micro-sample is moved in space and the spatial orientation of the micro-sample is altered. The method further includes holding the micro-sample in a second spatial orientation relative to the optical axis, wherein the second spatial orientation differs from the first spatial orientation.
Claims
1. A method, comprising: a) holding an extracted micro-sample and an adjacent hinge element via a holding device of a particle beam microscope so that the micro-sample has a first spatial orientation relative to an optical axis of a particle beam column of the particle beam microscope; b) producing a bending edge in the hinge element via irradiation with a beam of charged particles produced by the particle beam column to move the micro-sample in space to change its spatial orientation; and c) holding the micro-sample in a second spatial orientation relative to the optical axis the particle beam microscope, wherein the second spatial orientation is different from the first spatial orientation.
2. The method of claim 1, further comprising extracting the micro-sample from an original sample.
3. The method of claim 1, further comprising transferring the micro-sample to the holding device.
4. The method of claim 1, further comprising processing the micro-sample and/or analyzing the micro-sample.
5. The method of claim 1, wherein the holding device comprises a member selected from the group consisting of a manipulator needle, a gripper, and a sample receptacle.
6. The method of claim 1, wherein b) comprises producing a plurality of bending edges in the hinge element.
7. The method of claim 1, further comprising depositing material on the bending edge to stabilize the bending edge.
8. The method of claim 1, wherein the hinge element and micro-sample are a single piece.
9. The method of claim 1, wherein the particle beam column comprises an electron beam column configured to produce an electron beam; and the second spatial orientation of the micro-sample is such that a side face of the micro-sample to be examined is substantially perpendicular to the optical axis of the electron beam column.
10. The method of claim 1, wherein: the particle beam column comprises an ion beam column configured to produce a focused ion beam; the second spatial orientation of the micro-sample is such that a side face of the micro-sample to be examined is substantially parallel to the optical axis of the ion beam column; and the method further comprises using the focused ion beam to thin and/or polish the micro-sample.
11. The method of claim 1, wherein: the particle beam column comprises an electron beam column configured to produce an electron beam; the particle beam microscope further comprises an electron backscatter diffraction detector; and the method further comprises choosing the second spatial orientation of the micro-sample to perform Transmission Kikuchi Diffraction measurements of the micro-sample.
12. The method of claim 11, wherein the optical axis of the electron beam column and a normal of a surface of the micro-sample to be examined define an angle of from 0° to 30°.
13. The method of claim 11, wherein the optical axis of the electron beam column and a normal of a surface of the micro-sample to be examined define an angle that of 10°.
14. The method of claim 1, wherein: the particle beam column comprises an electron beam column configured to produce an electron beam; the particle beam microscope further comprises an electron backscatter diffraction; and the method further comprises choosing the second spatial orientation of the micro-sample to perform electron backscatter diffraction analyses of the micro-sample.
15. The method of claim 14, wherein the optical axis of the electron beam column and a normal of a surface of the micro-sample to be examined define an angle of from 0° to 50°.
16. The method of claim 1, wherein: the particle beam microscope comprises a scanning transmission electron microscopy detector; and the method further comprises choosing the second spatial orientation of the micro-sample so that STEM analyses can be carried out.
17. One or more machine-readable hardware storage devices comprising instructions that are executable by one or more processing devices to perform operations comprising the method of claim 1.
18. A system comprising: one or more processing devices; and one or more machine-readable hardware storage devices comprising instructions that are executable by the one or more processing devices to perform operations comprising the method of claim 1.
19. A method, comprising: a) holding an extracted micro-sample and an adjacent hinge element via a holding device of an electron beam microscope so that the micro-sample has a first spatial orientation relative to an optical axis of an electron beam column of the electron beam microscope; b) producing a bending edge in the hinge element via irradiation with a beam of electrons produced by the electron beam column to move the micro-sample in space to change its spatial orientation; c) holding the micro-sample in a second spatial orientation relative to the optical axis the particle beam microscope; and d) after c), processing the micro-sample and/or analyzing the micro-sample, wherein the second spatial orientation is different from the first spatial orientation.
20. A method, comprising: a) holding an extracted micro-sample and an adjacent hinge element via a holding device of an ion beam microscope so that the micro-sample has a first spatial orientation relative to an optical axis of an ion beam column of the ion beam microscope; b) producing a bending edge in the hinge element via irradiation with a beam of ions produced by the ion beam column to move the micro-sample in space to change its spatial orientation; c) holding the micro-sample in a second spatial orientation relative to the optical axis the particle beam microscope; and d) after c), processing the micro-sample and/or analyzing the micro-sample, wherein the second spatial orientation is different from the first spatial orientation.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) Exemplary embodiments of the disclosure are explained below with reference to figures. Therefore, in order to explain the components, reference is also made to the respectively preceding and subsequent description in its entirety.
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EXEMPLARY EMBODIMENTS
(11)
(12) A micro-sample 13 prepared to be free and extracted from an original sample is provided in a microscope system. To this end, the micro-sample 13 and an adjacent hinge element 12 are held on a holding device 11. As illustrated, the holding device 11 can be embodied as the needle of a manipulator, for example.
(13) Advantageously, the holding device 11 is arranged in a sample chamber 18 (not illustrated in
(14) In the example shown, the hinge element 12 is fastened directly to the manipulator needle 11, for example as a result of adhesion due to electrostatic forces, adhesive bonding (e.g., using a UV-curable adhesive), deposition of material (e.g., by particle beam-induced material deposition), sputtering (application of a sputter coating) or mechanical holding (e.g., with the aid of clamps or grippers).
(15) The micro-sample 13 is arranged directly adjacent to the hinge element 12 such that the micro-sample 13 is held by the manipulator needle 11 via the hinge element 12 (
(16) The hinge element 12 provides an additional degree of freedom of movement for the adjacent micro-sample 13. By way of example, it can be embodied as a thin film between micro-sample 13 and holding device 11.
(17) The hinge element 12 has a processing line 16, along which a focused particle beam 14, produced in the microscope system, is guided over the surface of the hinge element 12. By way of example, the particle beam 14 can be an ion beam which is produced in an ion beam column 21. As a result, sample material is ablated, with a bending edge 17 at which the hinge element 12 is shaped arising in the process (
(18) In this way, an exposed structure such as the hinge element can be shaped in contactless and permanent fashion. The plastic deformation produced at the processing line is possibly caused by electric charges and/or by thermal effects, which trigger internal tensions.
(19) In any case, shaping the hinge element 12 causes the adjacent micro-sample 13 to be moved in space. That is to say, the spatial orientation of the micro-sample 13 is altered.
(20) The bending edge 17 can be considered to be an axis about which parts of the hinge element 12 and the adjacent micro-sample 13 are rotated. Here, the relative position of this axis of rotation can be chosen freely by virtue of defining a processing line 16 along which the bending edge 17 should arise. The bending edge 17 can be aligned parallel to an outer edge of the TEM lamella, although this is not mandatory.
(21) The hinge element is shaped in contactless fashion. This means that the hinge element does not come into contact with a mechanical shaping tool, either directly or indirectly (e.g., by material deposition). Rather, the shaping is only caused by the action of the focused particle beam, wherein the focused particle beam can be a focused ion beam, for example.
(22) Thus, the micro-sample 13 initially adopts a first spatial orientation relative to the optical axes 20, 22 of the microscope system, as illustrated in
(23) Following the shaping of the hinge element 12, the micro-sample 13 adopts a second spatial orientation relative to the optical axes 20, 22. Here, it can be particularly advantageous if the second spatial orientation is chosen in such a way that the micro-sample 13 can be observed with the aid of the electron beam 15, which is produced in an electron beam column 19, and a suitable detector (not illustrated). It is also conceivable to choose the second spatial orientation in such a way that the micro-sample 13 can be processed in the microscope system, e.g., by milling (i.e., material ablation by ion irradiation), etching, or material deposition.
(24) However, changing the spatial orientation of the micro-sample can also be brought about by the interplay of beam-induced shaping and mechanical adjustment to the holding device (e.g., manipulator, gripper, sample holder) and/or the adjustment of the beam axis of the incident particle beam. The mechanical adjustment can be implemented in translational and/or rotational fashion.
(25) Moreover, it is also conceivable for a plurality of bending edges to be produced in the hinge element so that the hinge element is shaped at a plurality of points.
(26) Hinge element and micro-sample can be embodied as one piece in a particularly advantageous embodiment In other words: In this case, the hinge element is included by the micro-sample such that hinge element and micro-sample have the same or similar material composition.
(27)
(28) Initially (step S21), an extracted micro-sample is provided, which is adjacent to a hinge element and connected via the latter to a holding device. The holding a device can be the needle of a manipulator, a gripper, a sample holder, or a similar tool.
(29) A gripper (e.g., a microgripper) is a pliers- or forceps-like device, with the aid of which a microscopic sample can be grasped and held. A microgripper usually includes two gripping elements. However, it is also conceivable that use is made of clamps which hold the sample without an opening and closing mechanism being present.
(30) A sample holder is understood to mean a device which can receive at least one stub, wherein the stub is configured in such a way that it can hold and provide the sample to be examined. The sample holder is set up to be connected to the microscope system in order to hold the provided sample in the microscope system in such a way that such sample can be examined and/or processed.
(31) Thus, the micro-sample is held by the holding device in a first spatial orientation (step S22) relative to the optical axis or the optical axes of the microscope system. Preferably, the micro-sample in this case is arranged in the sample chamber of the microscope system in such a way that the micro-sample can be analyzed and/or processed without needing to be transferred to another holding device (e.g., outside of the microscope system).
(32) Then a bending edge is produced (step S23) by virtue of the hinge element being irradiated with a beam of charged particles. Advantageously, the bending edge is produced in the hinge element such that the hinge element is shaped, and the micro-sample connected to the hinge element is moved in space.
(33) Finally (step S24), the micro-sample is held in a second spatial orientation. The second spatial orientation facilitates further processing or analyzing of the micro-sample.
(34) A further advantageous embodiment of the method according to the disclosure is illustrated in
(35) A micro-sample that was prepared from a volume sample (original sample) is initially made available in this embodiment. Various known processes can be used for the preparation. The sample can be a vertical lamella, a horizontal lamella, or a wedge-shaped sample. However, it is also conceivable for the micro-sample to have a column-shaped or conical embodiment or to be embodied as a cone with a polygonal base area. Such sample shapes are used, for example, for tomographic analyses (e.g., x-ray tomography).
(36) In step S31 of the method according to the disclosure, the micro-sample is extracted from the original sample. To this end, the micro-sample is received in a holding device, for example a manipulator needle or a gripper. Then, the micro-sample is separated from the original sample and only still held by the holding device.
(37) Subsequently (step S32), the micro-sample detached from the original sample is transferred to a holding device.
(38) Then, the extracted micro-sample is held in a first spatial orientation in step S33.
(39) A bending edge is produced in the hinge element in step S34, as described for step S23 in
(40) The micro-sample is held in a second spatial orientation in step S35, the second spatial orientation differing from the first spatial orientation.
(41) Finally, the micro-sample is processed and/or analyzed (step S36).
(42) A further advantageous embodiment is shown in
(43) In the embodiment of
(44) This can be brought about by virtue of a suitable process gas being introduced by a cannula 47 while the micro-sample 46 is held on the holding device 42 (for example by a microgripper). It is also conceivable that a precursor gas is introduced, which is initially activated by irradiation with a particle beam 41 (electrons and/or ions). In any case, the particle beam microscope used to carry out the method should include a device with which the involved gases can be introduced into the vicinity of the bending edge. By way of example, a platinum-containing layer can be applied to the bending edge such that the depression arisen along the processing line is filled and the shaped form is fixed.
(45) As illustrated in
(46) It is also conceivable for different bending edges to be produced in succession in the hinge element in order to successively hold the micro-sample in a plurality of different spatial orientations. While the micro-sample is held in the individual alignments it can be subject to various processing or analysis steps in each case.
(47) The micro-sample is held by a sample receptacle in a further embodiment (
(48) A sample holder is usually understood to mean a device which can receive one or more sample carriers (stubs) at certain receptacle positions. In turn, the stub conventionally holds one sample directly, for example by way of a clamping mechanism or an adhesively bonded connection. In general, the sample holder can be reversibly fastened to a microscope system, usually on the displaceable microscope stage. Sample holders often have a complex geometry, the configuration of which can vary depending on the examining, processing, or imaging process, the microscope system used and the type of sample.
(49) In a specific configuration of the present disclosure (
(50) It is also conceivable for the micro-sample to still be included by an original sample, from which it was prepared, and for the entire original sample to be held on the sample receptacle 61.
(51) Advantageously, the sample receptacle can also be configured in such a way that it includes additional storage locations for micro-samples (e.g., TEM lamellas), for example a sample grid. A sample grid is understood to mean a grid-type net or perforated film for receiving a micro-sample. Moreover, specifically prepared areas, specific geometries, or specific orientations of a receptacle region can be made available on the sample receptacle.
(52) To prepare the particle beam-induced shaping according to the disclosure, micro-samples can be exposed from the respective original sample with different types of cut guides.
(53) By way of example, a U-shaped cut 66 can be carried out in order to expose the actual micro-sample 62 from the original sample, as illustrated in
(54) The overall sample includes a hinge element 63 and the actual micro-sample 62, which has a sample region of interest 65. The U-shaped cut 66 is arranged in such a way that the micro-sample 62 is only still connected to the hinge element 63 along a processing line 64. As already described, the hinge element 63 can be shaped in particle beam-induced fashion in order to alter the alignment of the micro-sample 62.
(55) Alternatively, an I-shaped cut 67 can be carried out. The preparation cuts can also be carried out in L-shaped or V-shaped fashion or in the form of a double I or can have any other arrangements. What is common to all these embodiments is that the micro-sample 62 is only connected to the hinge element 63 along a processing line 64 in each case, in order to facilitate the particle beam-induced shaping.
(56)
(57) A structure to be shaped can be shaped in beam-induced fashion in the direction of the incident particle beam. The shaping can be stopped by virtue of stopping the action of the particle beam. Therefore, it is possible to halt the shaping process once the desired extent of shaping has been achieved.
(58) On the other hand, the structure to be shaped can be shaped at most up to the incident particle beam.
(59) As illustrated in
(60) By way of example, an electron beam can subsequently pass through the thinned and/or polished micro-sample 73 so that transmitted electrons are captured by a suitable detector and used for image production purposes.
(61) In order to be able to carry out special detection applications, further specific embodiments of the method according to the disclosure, which are illustrated in FIGS. 8A-8E, are conceivable. In this case, the microscope system used to carry out the method includes an EBSD (electron backscattered diffraction) detector 80 and/or a STEM (scanning transmission electron microscopy) detector 800.
(62) The EBSD detector 80 can be arranged at different positions relative to the optical axes 86, 87 of the microscope system and relative to the micro-sample 84 (as shown in
(63) In these special embodiments of the method, too, a focused particle beam (for example an ion beam 85) is guided over the hinge element 82 along a processing line 83 such that the hinge element 82 is shaped in particle beam-induced fashion. As a result, the spatial orientation of the adjacent micro-sample 84 is altered relative to the optical axes 86, 87 of the utilized microscope system and relative to the respectively utilized detectors 80, 800. As a result of the particle beam-induced shaping, the micro-sample 84 can be aligned in such a way that, firstly, it can be irradiated with an electron beam 88 and, secondly, signals emitted by the micro-sample 84 can be detected by at least one of the detectors 80, 800.
(64) By way of example, the emitted signal particles can be backscattered electrons (BSE) such that an EBSD (electron backscattered diffraction) analysis is possible (
(65) Therefore, in a first special embodiment of the method for improved EBSD analysis, the second spatial orientation of the micro-sample 84 is chosen in such a way that the EBSD detector 80 can capture the side of the sample facing the primary electron beam. This ensures that the EBSD detector 80 is able to detect the backscattered electrons which move along the sketched-out trajectories of the signal particles 89.
(66) In this case, the micro-sample 84 can be aligned in such a way that the optical axis 87 and the normal N of the surface of the sample 84 form an angle α, the angular dimension of which is between 0° and 50°. However, it is also conceivable for the surface of the micro-sample 84 to be aligned substantially perpendicular to the optical axis 87 and hence to the incident electron beam 88. In this case, the dimension of the angle β is approximately 90°, wherein the angle β is included by the optical axis 87 and the surface of the sample 84. In this case, the angle α (between normal N of the sample surface and optical axis 87) is 0°.
(67) In a second special embodiment of the method, the signal particles emitted by the sample 84 are transmitted electrons, which can be used for TKD (Transmission Kikuchi Diffraction) measurements. In this case, the incident primary electron beam passes through the sample material and leaves the sample 84 in the form of transmitted electrons. Accordingly, the transmitted electrons emerge on the side of the sample facing away from the primary electron beam.
(68) To detect transmitted electrons, the second spatial orientation of the micro-sample 84 is chosen in such a way in the second special embodiment (TKD analysis) that the EBSD detector 80 can capture the side of the sample facing away from the primary electron beam.
(69) Depending on the arrangement of the EBSD detector 80 relative to the sample 84 and to the optical axis 87, it is advantageous if the area of the sample 84 to be irradiated adopts a certain angle β relative to the incident primary electron beam.
(70) By way of example, if the EBSD detector 80 is arranged on the side facing away from the electron beam 88 (
(71) In the case of a lateral arrangement of the EBSD detector 80, it is advantageous, however, to tilt the micro-sample 84, as illustrated in
(72) A third special embodiment of the method can be used for transmission examinations using a scanning electron beam microscope. Transmitted electrons are also detected in this case. The microscope system used includes a STEM detector 800 for detecting transmission electrons. The STEM detector 800 is arranged on the side of the sample facing away from the incident primary particle beam. In this case, too, it can be particularly advantageous if the area of the micro-sample 84 to be irradiated is arranged substantially perpendicular to the incident primary electron beam such that the angle β is approximately 90°.
(73) Moreover, other tilt angles in which the involved degrees of freedom of movement are made available by additional tilt devices are also conceivable in all special embodiments described.
(74) Advantageously, the various embodiments of the method according to the disclosure are carried out with a two-beam apparatus (FIB-SEM combination apparatus), which is illustrated in
(75) Usually, the micro-sample 102 is received in a sample stage 101 for this purpose and is located in the sample chamber 96 of the two-beam apparatus 90, in which there are vacuum conditions.
(76) The sample stage 101 is advantageously embodied as a five-axis sample stage. This means that the sample receptacle can be displaced in the x-, y- and z-direction—i.e., in three mutually perpendicular spatial directions—and can be rotated about a tilt axis and an axis of rotation. Optionally, further movement axes may be present.
(77) By way of example, the axis of rotation can be aligned perpendicular to one of the spatial directions. The rotation about the tilt axis, which extends perpendicular to a plane spanned by the optical axes 94, 106 (i.e., perpendicular to the plane of the drawing), renders it possible to allow the surface of the sample 102, which is intended to be irradiated by charged particles, to adopt different adjustable angles in relation to the optical axes 94, 106.
(78) Consequently, five degrees of freedom of movement, specifically three translational and two rotational degrees of freedom of movement, are made available for the received micro-sample 102. An additional degree of freedom of movement can be provided by the inventive, ion beam-induced reshaping of a hinge element adjacent to the micro-sample 102. Further degrees of freedom of movement can be provided by the sample holder, manipulator and/or gripper.
(79) During the operation of the two-beam apparatus 90, primary electrons are produced in the electron source 92 and the electrons are accelerated along the optical axis 94 of the electron beam column 91, focused by the lens systems 93, 95, and clipped by at least one aperture stop 108. Moreover, the electron beam column 91 includes a deflection system 97, by which the primary electron beam can be guided over the sample 102 in a grid-like fashion. Furthermore, the FIB-SEM combination apparatus 90 includes at least one detector 98 for detecting interaction products of the interaction of the electrons and/or ions with the sample 102.
(80) In a particularly advantageous configuration of the two-beam apparatus, the objective lens can be arranged at the sample-side end of the electron beam column and includes the deflection system.
(81) Moreover, the FIB-SEM combination apparatus 90 includes an ion beam column 107 with an ion source 105, a deflection system 104 and focusing lenses 103. The ions produced in the ion source 105 are accelerated along the optical axis 106 of the ion beam column 107 and focused such that the ions are incident on the sample 102 in focus and can be used to ablate material from the sample 102 and/or image the sample 102.
(82) It can be particularly advantageous for the two-beam apparatus 90 to moreover include a gas injection system (GIS) 100. The latter usually includes a reservoir for a process gas which can be supplied in a controlled fashion to the sample 102 via a line that ends near the processing location. The process gas can be embodied as a precursor gas. In this case, the precursor gas is initially activated by the ion beam or the electron beam and thus converted into a reactive form that is able to ablate sample material or deposit material on the sample 102. With the aid of a suitable detector 98, the progress of the processing of the sample 102 can be observed simultaneously or successively by way of irradiation with electrons.
(83) Moreover, the two-beam apparatus 90 can include an evaluation and control unit 99. The evaluation and control unit 99 can carry out a sequence of control commands, which are included in a computer program product. By carrying out of the control commands, the two-beam apparatus 90 is prompted to carry out an embodiment of the method according to the disclosure for changing the spatial orientation of a micro-sample.
(84) This is not restricted to a two-beam apparatus. Other particle beam apparatuses used to carry out the method according to the disclosure can be prompted by way of an appropriate computer program product to carry out a sequence of control commands such that an above-described method for changing the spatial orientation of a micro-sample is carried out.
REFERENCE SIGNS
(85) 11 Holding device (manipulator needle) 12 Hinge element 13 Micro-sample 14 Focused ion beam 15 Electron beam 16 Processing line 17 Bending edge 18 Sample chamber 19 Electron beam column 20 Optical axis of the electron beam column 21 Ion beam column 22 Optical axis of the ion beam column S21 Provide extracted micro-sample S22 Hold micro-sample in the first spatial orientation S23 Produce bending edge S24 Hold micro-sample in the second spatial orientation S31 Extract micro-sample from the original sample (volume sample) S32 Transfer micro-sample to the holding device S33 Hold micro-sample in the first spatial orientation S34 Produce bending edge and shape S35 Hold micro-sample in the second spatial orientation S36 Process/analyze micro-sample 41 Particle beam 42 Gripper (e.g., microgripper) 43 Hinge element 44 Deposited material 45 Bending edge 46 Micro-sample 47 Cannula (gas injection system) 48 Holding device 51 First processing line 52 Second processing line 551 First bending edge 552 Second bending edge 61 Sample receptacle 62 Micro-sample 63 Hinge element 64 Processing line 65 Sample region of interest 66 U-shaped cut 67 I-shaped cut 71 Holding device 72 Hinge element 73 Micro-sample 74 Optical axis 75 Ion beam 76 Electron beam 80 EBSD detector 81 Holding device 82 Hinge element 83 Processing line 84 Micro-sample 85 Ion beam 86 First optical axis 87 Second optical axis 88 Electron beam 89 Trajectories of the signal particles 800 STEM detector N Normal of the surface of the sample 90 Two-beam apparatus 91 Electron beam column 92 Electron source 93 First condenser lens system 94 Optical axis of the electron beam column 95 Second condenser lens system 96 Sample chamber 97 Deflection system 98 Detector 99 Evaluation and control unit 100 Gas injection system 101 Sample stage 102 Micro-sample 103 Focusing lens 104 Deflection system 105 Ion source 106 Optical axis of the ion beam column 107 Ion beam column 108 Aperture stop