Sample holder for cutting and in situ analysis by secondary ion mass spectrometry

Abstract

Sample holder for cutting and in situ analysis by secondary ion mass spectrometry. The invention relates to a sample holder device (1) for cutting a sample (3) by an ion beam (200) and in situ analysis by secondary ion mass spectrometry. The device (1) comprises a pivot module (10) having two support surfaces (S1, S2) defining a tilt angle α. The device (3) is configured to be tilted rotationally from one support surface to another between the cutting and analysis configurations. The device (1) further comprises a holding module (11) having a compartment (110) for the sample (3), and a masking portion (111) configured to, in the cutting configuration, partially mask the sample (3) from the ion beam (200). Figure for the abstract: Fig. 1B

Description

Title of the invention: Sample holder for cutting and in situ analysis by secondary ion mass spectrometry. Technical field

[0001] The present invention relates to the field of sample preparation and in situ analysis by secondary ion mass spectrometry. Its application is particularly advantageous in the field of in situ analysis by time-of-flight secondary ion mass spectrometry, and in particular under so-called cryogenic conditions. STATE OF THE ART

[0002] Secondary ion mass spectrometry (SIMS) is a commonly used surface analysis technique. In this technique, a surface of the sample to be analyzed is bombarded with an ion beam. The sample is then atomized, and some of the atomized material is ionized. These secondary ions are then accelerated to a mass spectrometer, which allows for the measurement of information relating to the chemical composition of the sample surface. The so-called "time-offlight" (TOF-SIMS) technique can be used for this purpose.

[0003] In order to obtain chemical information within the volume of the sample, it may be advantageous to cut the sample before the analysis to expose a cross-sectional area, so as to analyze a surface rather than a volume. It is this exposed cross-sectional area that is then analyzed by SIMS.

[0004] Sample preparation is often a limiting step because it sometimes requires high manual precision and can damage or alter the sample. In the case of biological samples, for example, preparation is often delicate because the samples are not stable under ultra-high vacuum, except at cryogenic temperatures. Performing the preparation in situ, that is, in the spectrometer in which the analysis will take place, offers many advantages because it avoids transfers that can also damage the sample.

[0005] For this purpose, the spectrometer includes an ion beam gun configured to cut or abrade the sample. Existing methods for performing in-situ sectioning are generally carried out using a focused ion beam (commonly abbreviated FIB). These ion beams can be of different types, but the most commonly used are Ga+, Bi+, and gas cluster ion beams (commonly abbreviated GCIB). They allow the sample to be abraded over a small area (maximum a hundred microns). Beyond this depth, and considering the relative positions between the ion beam gun for cutting and the SIMS analyzer, a reorientation of the sample is required because the ion ejection for SIMS analysis has a shallow depth of field (typically about 10 to 100 pm).

[0006] The document Christian Schneider, Harald Weigand, Marcus Rohnke; Improving SIMS imaging of FIB bevel cuts with an elaborate sample holder. J. Vac. Sci. Technol. B 1 May 2018; 36 (3): 03F101, describes a motorized sample holder for TOF SIMS analysis. The sample holder is used to perform an in situ FIB etch. The sample holder includes an electric motor and several deflections to adjust the sample position between a cutting configuration and an analysis configuration. This solution, however, remains complex to implement, can damage the sample, and is limited in terms of SIMS analysis.

[0007] An object of the present invention is therefore to propose an improved solution for cutting a sample and in-situ analysis by secondary ion mass spectrometry, and in particular for in-situ analysis by time-of-flight secondary ion mass spectrometry (TOF-SIMS).

[0008] The other objects, features, and advantages of the present invention will become apparent from an examination of the following description and accompanying drawings. It is understood that other advantages may be incorporated. SUMMARY

[0009] To achieve this objective, according to a first aspect, a sample holder device is provided for cutting at least one sample by an ion beam and in situ analysis by mass spectrometry of secondary ions, having a first configuration called "cutting" in which the sample is intended to be in a first position, and a second configuration called "analysis" in which the sample is intended to be in a second position, the first position being distinct from the second position, the device being configured so as to rotate the sample between the first position and the second position during the passage between the cutting configuration and the analysis configuration.

[0010] Advantageously, the device comprises: - a pivot module comprising at least two support surfaces defining between them, at the level of an axis of rotation, a tilting angle α, the device being supported on one of said support surfaces in the cutting configuration, and the device being supported on another of said support surfaces in the analysis configuration, the device being configured to be tilted in rotation around the axis of rotation during the transition between the cutting configuration and the analysis configuration, - a support module comprising: • a housing configured to accommodate the sample, • a masking portion configured to, in the cutting configuration, partially mask the sample from the ion beam when the sample is placed in the housing.

[0011] The housing with the masking portion allows the sample to be cut by a gas cluster ion beam (more commonly known by the acronym GCIB). A GCIB is less precise in cutting because the beam is wider and more diffuse. However, the GCIB is faster than a FIB on organic and biological samples and causes less molecular fragmentation on the sample surface. The device thus allows for faster and higher-quality cutting of a three-dimensional sample, and not necessarily only of planar multilayer stacks, as is the case in conventional solutions. Furthermore, the sample holder is compatible with extremely rough samples for which it is difficult to perform a flat cut.

[0012] Since the tilting of the sample holder is limited, the two support surfaces allow for simple, robust, and reliable in-situ tilting of the device between the cutting and analysis positions by pivoting. Handling of the cut sample is reduced while ensuring reproducible placement thanks to the two support surfaces. The sample holder allows for an angled cut and subsequent reorientation within the instrument, even in instruments that do not offer sufficient pivoting of the sample holder. Abrasion conditions can be improved while optimizing the extraction of the analyzed secondary ions. Artifacts are thus limited, and the measured signal is increased.

[0013] The sample holder device is thus made compatible with ambient cutting and in situ analysis conditions, but also with so-called "cryogenic" cutting and in situ analysis conditions, which is particularly advantageous for biological and / or organic samples, which can frequently be three-dimensional. The risk of a motorized sample holder freezing is limited. Cryogenic conditions also minimize changes to the surface chemistry of the samples.

[0014] The tilting angle can also be adapted according to the manufacture of the sample holder, for example according to the instrument configurations and the relative placement of the cutting and analysis barrels.

[0015] A second aspect relates to an in situ analysis instrument by secondary ion mass spectrometry comprising an ion beam gun, preferably a gaseous ion cluster gun, the instrument further comprising: - a sample holder plate, - the sample holder device according to the first aspect, arranged on the sample holder plate, - a so-called tilting element, configured to switch the sample-holding device between the cutting configuration and the analysis configuration.

[0016] A third aspect relates to a method for cutting and in-situ analysis by mass spectrometry of secondary ions of a sample, comprising: - a sample arrangement in a sample holder device comprising a holding module, the holding module comprising a housing configured to accommodate the sample, - the device comprising a pivot module including at least two support surfaces defining between them, at the level of an axis of rotation, a tilting angle a, an arrangement of the device housing the sample on the sample-holding stage of an in situ analysis instrument by secondary ion mass spectrometry, such that the device is in a first configuration called cutting in which the device supports one of said support surfaces, - in the cutting configuration, a cutting of the sample by an ion beam, in which the sample in the housing is partially masked from the ion beam by a masking portion of the holding module, so as to expose after cutting a cross-sectional surface of the sample, - a transition of the device from the cutting configuration to a second configuration, known as the analysis configuration, by rotating the device around the axis of rotation Al so as to place the device against another of the said support surfaces, - a mass spectrometry analysis of secondary ions of the exposed cross-sectional surface of the sample.

[0017] According to a fourth aspect, a manufacturing process for the sample holder device according to the first aspect is provided, comprising machining, preferably by electro-erosion, so as to form the pivot module having its tilting angle, the housing and the masking portion.

[0018] According to one example, the method further includes polishing one face of the device on which the housing is placed, so as to define a depth of the housing.

[0019] According to one example, the method further includes machining the edge of the masking portion, preferably by Plasma Focused Ion Beam. BRIEF DESCRIPTION OF THE FIGURES

[0020] The aims, objects, features and advantages of the invention will become clearer from the detailed description of an embodiment thereof, which is illustrated by the following accompanying drawings in which:

[0021] [Fig.1A] Figures IA to 1D represent cutting and analysis steps of the process implementing the sample holder device, according to an example embodiment.

[0022] [Fig.lB] [Fig.lC] [Fig.lD]

[0023] [Fig.2] Figures 2 to 5 represent a longitudinal sectional view of the sample holder device in the cutting configuration, according to several embodiment examples.

[0024] [Fig.3] [Fig.4] [Fig.5]

[0025] [Fig.6] Fig.6 represents a variant of the tilting member of the sample holder device, according to an embodiment distinct from those shown in Figures 2 to 5.

[0026] [Fig.7A] Figures 7A and 7B represent a longitudinal sectional view of the sample holder device in the cutting configuration, according to two embodiments in which the holding module includes several housings.

[0027] [Fig.7B]

[0028] [Fig. 8A] Figures 8A to 8C represent a cross-sectional view of the sample holder device, according to three specific examples of the housing of the support module.

[0029] [Fig.8B] [Fig.8C]

[0030] [Fig.9A] Figures 9A to 9C represent a cross-sectional view of the sample holder device, according to three particular embodiments of the edge of the retaining module.

[0031] [Fig.9B] [Fig.9C]

[0032] [Fig.1OA] Figures 10A and 10B represent a longitudinal sectional view of the sample holder device, according to two embodiments in which the device includes an element configured to modify at least one depth of the housing and / or at least one height of the edge.

[0033] [Fig.1OB]

[0034] The drawings are given by way of example and are not limiting of the invention. They constitute schematic representations of principle intended to facilitate understanding of the invention and are not necessarily to scale with practical applications. In particular, the relative dimensions between the sample holder, the instrument, and the sample are not necessarily representative of reality. DETAILED DESCRIPTION

[0035] Before beginning a detailed review of embodiments of the invention, optional features which may possibly be used in association or alternatively are stated below.

[0036] According to one example, the masking portion comprises at least one surface designed to be positioned obliquely to the ion beam to define at least one edge that partially masks the sample from the ion beam. The sample is thus masked by a point relief along the propagation direction of the cutting ion beam. This limits the risk of material deposition from the masking portion. Furthermore, the curtain effect during cutting is reduced. The quality of the cutting, and therefore of the subsequent analysis, is thus improved.

[0037] According to one example, the sample holder device is made of metal.

[0038] According to one example, the tilt angle α is between 120° and 160°, preferably between 125° and 145°, and preferably approximately 135°. During the development of the invention, it was found that this angle range was particularly suitable for obtaining a high-quality cut, especially by GCIB, and subsequently in the analysis configuration to optimize the extraction and analysis of secondary ions. This angle can vary depending on the instrument configuration. This angle can be adjusted according to the angle of incidence of the ion beam for the cut.

[0039] According to one example, the pivot module comprises a first arm including a first support surface and a second arm including a second support surface.

[0040] According to one example, the holding module is arranged on the second arm, the holding module being further configured so that the housing and the masking portion are raised relative to the second arm. For sectioning and analysis, the sample is thus placed in a working area raised relative to the pivot module. The quality of the sectioning and subsequent analysis will be improved. This also limits the risk of the pivot module contacting the instrument's analyzer.

[0041] According to one example, the pivot module includes a third support surface disposed between a first and a second support surface, the third support surface defining, with each of the first and second support surfaces, a secondary tilting angle a2, a3. The third support surface makes it possible to obtain more different angular positions for cutting or analysis configurations, as required and for example to adapt to different instrument configurations.

[0042] According to one example, in the cutting configuration, the device is supported on one of the first and third support surfaces, preferably the first support surface.

[0043] According to an example, in the analysis configuration, the device is supported on one of the third and second support surfaces, preferably the second support surface. Whereas in the cutting configuration the device is supported on the third support surface, in the analysis configuration the device is supported on the second support surface.

[0044] According to one example, the holding module comprises a plurality of compartments, each configured to hold a sample. The device thus makes it possible to produce several samples in a single cutting step, particularly when the cutting is performed by GCIB.

[0045] For example, at least two dwellings in the plurality of dwellings have different depths, preferably each dwelling in the plurality of dwellings has a different depth. The device thus makes it possible to obtain several samples cut at different depths in a single cutting step, particularly when the cutting is performed by GCIB. The subsequent SIMS analysis can then provide data at different depths of the samples.

[0046] According to one example, in the cutting configuration, the device is configured to cut the sample at a different depth at different points on the sample: - the masking portion being oblique and / or comprising reliefs arranged at different heights from each other, and / or - the dwelling having an oblique floor and / or including reliefs arranged at different heights from each other.

[0047] The device thus makes it possible to cut the same sample at different depths between different locations of the sample, particularly when the cutting is performed by GCIB. The subsequent SIMS analysis can therefore make it possible to obtain data at different depths of the sample.

[0048] According to one example, the device further comprises a component configured to modify at least one depth of the housing and / or at least one height of the masking portion. The cutting depth of the sample can thus be adapted as needed.

[0049] According to one example, the pivot module having a face opposite each of the support surfaces, and in which the tilting member is configured to alternately exert a force on one of said faces, so as to maintain the device respectively in the cutting configuration and in the analysis configuration. The switching between cutting and analysis configurations and maintaining the device in a given configuration is thus done in a simple and robust manner, and is compatible with cutting and analysis under cryogenic conditions.

[0050] According to one example, the tilting mechanism includes a motor configured to tilt the device between the cutting configuration and the analysis configuration. The tilting between the cutting and analysis configurations can thus be controlled by a motor, which can provide greater flexibility in adjusting the tilting and relative positions of the device between the cutting and analysis configurations.

[0051] According to one example, the process further comprises, prior to cutting the sample, cooling the sample to a temperature strictly below 0°C, preferably below or equal to -140°C. The process thus carries out the cutting and preferably also the subsequent analysis under cryogenic conditions. The process is therefore particularly suitable for biological and / or organic samples, especially below -140°C.

[0052] According to one example, the sample is a biological and / or organic sample. In the case of organic and / or biological samples, very large areas can be rapidly abraded in an automated manner (typically up to 800 µm laterally) and difficult and manual preparation procedures (e.g., cryo-ultramicrotomy, cryo-transfer, etc.) can be avoided.

[0053] In the following description, the term "on" does not necessarily mean "directly on." Thus, when it is stated that a part or component A is supported "on" a part or component B, this does not mean that parts or components A and B are necessarily in direct contact with each other. These parts or components A and B may be either in direct contact or supported by each other via one or more other parts. The same applies to other expressions such as, for example, the expression "A acts on B," which may mean "A acts directly on B" or "A acts on B via one or more other parts."

[0054] In the present patent application, the term mobile corresponds to a rotational movement or a translational movement or a combination of movements, for example the combination of a rotation and a translation.

[0055] In this patent application, when two parts are described as distinct, this means that these parts are separate. They may be: - positioned at a distance from each other, and / or - mobile relative to each other and / or - joined together by being fixed by added elements, this fixing being removable or not.

[0056] A single-piece unit cannot therefore be made up of two separate parts.

[0057] In this patent application, the term "fixed" used to describe the connection between two parts means that the two parts are linked / fixed to each other with respect to all degrees of freedom, unless explicitly specified otherwise. For example, if it is stated that two parts are fixed in translation along a direction X, this means that the parts can be movable relative to each other, possibly with respect to several degrees of freedom, excluding freedom in translation along the direction X. In other words, if one part is moved along the direction X, the other part moves in the same direction.

[0058] In the detailed description that follows, terms such as "horizontal," "vertical," "longitudinal," "transverse," "upper," "lower," "top," "bottom," "front," "rear," "inside," and "outside" may be used. These terms should be interpreted relatively in relation to the normal position of the sample-holding device on the sample-holding plate. For example, the terms "horizontal" and "longitudinal" correspond to the principal extension direction of the surface of the sample-holding plate on which the device rests, or to the principal extension direction of the first arm of the pivot module in the cutting configuration.

[0059] A reference frame will also be used whose longitudinal or rear / front direction corresponds to the X axis, whose transverse or right / left direction corresponds to the Y axis and whose vertical or bottom / top direction corresponds to the Z axis.

[0060] For the purposes of this disclosure, the expression "A and / or B" means (A), (B), or (A and B). For the purposes of this disclosure, the expression "A, B and / or C" means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C).

[0061] A parameter "approximately equal to / greater than / less than" a given value means that this parameter is equal to / greater than / less than the given value, to within ±10% of that value. A parameter "approximately between" two given values ​​means that this parameter is at least equal to the smaller of the given values, to within ±10% of that value, and at most equal to the larger of the given values, to within ±10% of that value.

[0062] Device 1, instrument 2 and associated methods are now described according to several particular embodiments with reference to the figures.

[0063] As illustrated in Figures IA to 1D, the instrument 2 for in situ analysis by secondary ion mass spectrometry typically comprises a chamber 25 in which a sample-holding stage 22 is disposed, hereinafter referred to as stage 22. In the following, the instrument 2 is equivalently referred to as spectrometer 2.

[0064] Conventionally, chamber 25 may include or be connected to an ion beam gun 20 configured to emit an ion beam 200 to slice the sample 3. Preferably, the gun 20 is a GCIB gun emitting, more particularly, a cluster of argon Ar25Oo+- ions. Chamber 25 may include or be connected to a gun 21, configured to emit an ion beam 210 for SIMS analysis, and more particularly a bismuth Bi3+ ion beam. Chamber 25 further includes an analyzer, not shown in the figures, configured to capture secondary ions resulting from the bombardment of the sample by the ion beam 210. The spectrometer 2 is preferably a TOF-SIMS spectrometer, but may be a quadropole gold magnetic sector spectrometer.

[0065] Sample 3 can thus be cut and analyzed in situ, that is to say that the cutting and the analysis take place in the spectrometer 2, and more particularly in the chamber 25 of the spectrometer 2. Preferably, sample 3 has not been removed from the chamber 25 between cutting and analysis.

[0066] The chamber 25, and more particularly the stage 22, can also be connected to a temperature control module 24, and more particularly a cooling module. The cooling module 24 can be configured to lower the sample temperature to a temperature strictly below 0°C, and preferably below or equal to -140°C. This makes it possible to achieve so-called "cryogenic" conditions, also referred to as "cryo" hereafter, for cutting and / or in situ analysis of the sample 3.

[0067] Performing the cutting under cryogenic conditions is useful because it minimizes local heating during the cutting and therefore reduces the damage caused to the sample 3, both in terms of curtaining effect and molecular damage that can be caused to the sample 3. Cryo conditions are also particularly suitable for making hydrated samples, for example biological samples, compatible with an ultra-high vacuum environment as is used for cutting and analyzing the sample.

[0068] Stage 22 can be configured to be inclined relative to the horizontal X direction. However, the inclination of stage 22 is generally limited in angle, typically within an angular range of ±10°. For sample analysis at a significant depth of section (e.g., greater than or equal to one hundred pm), the sample must be reoriented since the ion ejection for TOF-SIMS analysis has a limited depth of field. The quantity of ions recovered by the spectrometer is also increased when a sample is "flattened".

[0069] For this purpose, the sample holder device 1, hereinafter referred to as device 1, is placed on the stage 22. Device 1 has two configurations: - a cutting configuration in which the sample 3 on the device 1 is positioned so as to be cut by the ion beam 200, to form an exposed cutting surface 3a, - an analysis configuration in which the sample 3 on the device 1, once the sample has been cut, is positioned so that the cutting surface 3a is exposed to the beam 210.

[0070] The device 1 includes a pivot module 10 allowing passage between the cutting configuration and the analysis configuration, and a holding module 11 on which the sample 3 is placed.

[0071] The pivot module 10 has at least two support surfaces SI and S2. These two support surfaces define, at the level of the rotation axis Al, a tilt angle α, which can also be designated as the principal tilt angle ai. The rotation axis Al is preferably parallel to the transverse direction Y. In the cutting configuration, the device 1 can be supported on the first support surface SL. In the analysis configuration, the device 1 can be supported on the second support surface S2. The transition from the cutting configuration to the analysis configuration can be actuated by a tilting member 23 located in the chamber 25 of the spectrometer 2, inducing a rotation of the device around the rotation axis Al, to change the support surface. Preferably, the two support surfaces SI and S2 are at least partially, and preferably entirely, flat.

[0072] The device 1 further includes a holding module comprising a housing 110 for the sample 3 and a masking portion 111 configured to partially mask the sample 3 disposed in the housing 110, when exposed to the ion beam 200, and in particular a GCIB 200.

[0073] Sample 3 can be placed on device 1, itself placed on stage 22 of spectrometer 2, as illustrated in [Fig. 1A]. Sample 2 can be placed in housing 110 as close as possible to the masking portion 111. Sample 3 can be fixed in housing 110, for example by the ice that forms at the interface between sample 3 and device 1 under cryo conditions, or by means of an adhesive material.

[0074] In the cutting configuration, and as illustrated for example by [Fig. IB], the sample 3 can be exposed to the GCIB 200. Since the GCIB beam is by nature wider and more diffuse than a FIB, the masking portion 111 masks part of the sample 3 in order to delimit the cutting surface 3a which is formed.

[0075] After the sample 3 has been cut, the tilting member 23 can be actuated to switch to the analysis configuration. The device 1 can thus be tilted to be placed against surface S2, as illustrated for example in [Fig. 1C]. The cutting surface 3a is thus reoriented to be exposed to the 210 ion beam for SIMS analysis, as illustrated for example in [Fig. 1D]. The position of sample 3 is therefore distinct between the cutting configuration and the analysis configuration.

[0076] Depending on the instrument designs, the switchover between the cutting configuration and the analysis configuration can be performed under various experimental conditions, for example, under vacuum, cryogenic conditions, or at room temperature, and / or under a protected atmosphere. In particular, the experimental conditions used during cutting can be maintained during the switchover between the cutting configuration and the analysis configuration, and preferably during the analysis.

[0077] The invention is particularly well-suited for making large-dimension cuts (for example, over at least one dimension greater than or equal to 100 pm). The invention utilizes the difference in abrasion rate by the ion beam 200 between the metallic mask formed by the masking portion 111 and the sample 3, for which very high cutting speeds can be achieved (up to 1 pm per minute for a sample containing organic materials). The cutting surface can have at least one dimension, and in particular, depending on the direction of propagation of the ion beam 200, substantially less than or equal to 300 pm in depth, and potentially more.

[0078] The invention is compatible with samples having a high topology. It is also suitable for biological samples for which cryogenic analysis is advantageous. It is also suitable for samples comprising organic materials.

[0079] By way of non-limiting examples, the following applications may be cited: - the study of the spatial distribution of lipids in seeds, - the TOF-SIMS study of different biological tissues (cells, animal tissues, plant tissues), - TOF-SIMS analysis of non-biological organic samples, such as hydrogels, polymers, etc. - TOF-SIMS analysis of composite organic and inorganic samples, the inorganic part preferably being smaller than the organic part, - the TOF-SIMS study of rough samples for which it would be necessary to perform a preliminary cutting or polishing of the surface.

[0080] Between cutting and analysis, the device 1 is preferably not removed from the chamber 25 of the spectrometer 2. The device 1 is mobile between its cutting configuration and its analysis configuration, and preferably mobile only in rotation around the axis Al. Between cutting and analysis, the device 1 can preferably be moved only in rotation around the axis Al. The actuation of the tilting member 23 can be controlled from outside the chamber 25 of the spectrometer 2, for example via a user interface or mechanical control means, not shown in the figures.

[0081] The retaining module 11 can be fixed to the pivot module 10, at least with respect to rotational movement about the axis A1, and preferably with respect to all degrees of freedom. The retaining module 11 can be a single piece with the pivot module 10. In one example, the retaining module 11 and the pivot module form a single unit.

[0082] For example, and as illustrated by Figures 2 to 7B, the pivot module 10 may comprise a first arm 100 and a second arm 101. The first arm 100 carries the first support surface SL. The second arm 101 carries the second support surface S2. The holding module 11 may be disposed on the second arm 101, for example, by being positioned in continuity with it along the main extension direction of the second arm 101. The tilt angle is preferably chosen so that the second arm 101 has a main extension direction substantially parallel to the propagation direction of the ion beam 200 when the device 1 is in the cutting configuration.

[0083] The tilt angle a is therefore between 120° and 160°, preferably between 125° and 145°, preferably is substantially equal to 135°. Equivalently, when the device 1 is in its cutting configuration, the second support surface S2 forms with the horizontal plane, and for example the surface of the plate 22, an angle substantially between 20° and 60°, preferably between 35° and 55°, and preferably substantially equal to 45°.

[0084] Several solutions can be considered for the tilting member 23. As illustrated in Figures 2 to 5, for example, the tilting member 23 can be configured to exert a holding force on the device 1. For this purpose, each arm 100, 101 can have a face 100a, 101a opposite the corresponding bearing surface SI, S2. The tilting member 23 can be configured to exert a bearing force on the face 100a or 101a depending on whether the device 1 is in the cutting or analysis configuration. The tilting member 23 can, for example, be a metal wire bearing on the face 100a, 101a in question (see, for example, [Fig. 2]), or a flexible tab bearing on the face 100, 101a in question (see, for example, Figures 3 to 5). The switch between the cutting and analysis configurations can be made by moving the tilting member 23 to be supported alternately on face 100a or face 101a.

[0085] Alternatively or in addition, the tilting member 23 may include a motor 231 configured to drive an actuator 230, inducing the tilting of the device 1 between its cutting and analyzing configurations. According to this example, the tilting member 23 may include a toothed wheel driven by a motor and a spring.

[0086] Device 1 is now described in more detail according to various embodiments. As illustrated in Figures 2 to 6, in the cutting configuration, the housing 110 extends, for example, in a first direction substantially perpendicular to the axis of rotation Al, and in particular a direction in the XZ plane. The housing 110 can extend in the first direction, this direction being substantially parallel to the main extension direction of the second arm or substantially parallel to the second support surface S2. The housing 110 has a hollow internal volume 1100 in which the sample 3 is placed.

[0087] The masking portion 111 can be configured to partially mask the housing 110 along a plane substantially perpendicular to this first direction, this plane being substantially parallel to the axis of rotation AL. The masking portion 111 can be configured to mask all or part of this internal volume 1100. In particular, the masking portion 111 can form an edge 110a of the internal volume 1100 of the housing 110. It is therefore understood that the masking portion 111 can partially delimit the housing 110, and in particular along the plane specified above.

[0088] According to a first example which can be illustrated by [Fig.2], the masking portion 111 has a top surface 111a oriented substantially parallel to the direction of propagation of the ion beam 200. In this embodiment, the ion beam 200 can ionize the surface of the masking portion 111 and redeposit the ionized material on the cutting surface 3a of the sample 3. This can be useful for increasing the signal during SIMS analysis.

[0089] However, it may be desirable to avoid contamination of the cutting surface 3a by the material of the device 1. As illustrated, for example, in Figures 3 to 10B, the surface 111a may be positioned obliquely with respect to the ion beam 200. The surface 111a may be non-parallel to the support surface S2, and more specifically, may form an acute angle with it. Note that it is preferable to avoid too small an angle between the surface 111a and the support surface S2, in order to limit the risk of electric arcing during SIMS analysis. The surface 111a thus forms an edge 1110.

[0090] The masking portion 111 can be configured to define a visible portion of the sample 3 and a masked portion of the sample 3, with the edge 1110 alone delimiting the visible and masked portions of the sample 3. Preferably, the edge 1110 is planar, preferably entirely planar or formed of several planar portions. The planarity of the edge 1110 improves the quality of the cutting surface 3a obtained, and limits the so-called "curtain" effects to the surface 3a of sample 3 (that is to say that sample 3a presents on the surface reliefs typically resulting from defects in flatness or excessive roughness of the masking portion 111).

[0091] As illustrated for example in [Fig. 4], the retaining module 11 can be configured so that the housing 110 and the masking portion 111 are raised relative to the second arm 101, and in particular relative to the face 101a of the second arm 101, opposite the second support surface S2. In other words, the second arm 101 can have a thickness DI strictly less than the distance D6 extending from the support surface to the opening of the housing 110 and, where applicable, the edge 1110. The working area is thus raised relative to the pivot module 10. For example, the distance D6 is greater than or equal to 1.5*D1, preferably greater than or equal to 2*D1.

[0092] The pivot module 10 can be configured so that it can be tilted according to a number of tilt angles strictly greater than 2. The adjustment of the tilt angle makes it possible to perform a pseudo-tomography by abrading and then imaging a given angular sector.

[0093] As illustrated, for example, in [Fig. 5], the pivot module 10 may include at least one third bearing surface S3 disposed between the bearing surfaces SI and S2. The third bearing surface S3 defines, with each of the first SI and second S2 bearing surfaces, a secondary tilt angle a2, a3. The secondary tilt angles a2, a3 may or may not be equal to each other. The bearing surface S3 may serve as a bearing surface in either the analysis and cutting configurations. For example, when the device 1 is supported on the first bearing surface SI in the cutting configuration, the device 1 may be placed in the analysis configuration supported on the second bearing surface S2 or the third bearing surface S3. Device 1 can be supported on the third support surface S3 in the cutting configuration, device 1 can then be placed in the analysis configuration supported on the second support surface S2.It is therefore understood that the third bearing surface S3 offers greater angle modularity for the device 1. A face 102a can be positioned opposite the third bearing surface S3, for example, to support the tilting member 23 on this face 102a. The bearing surface S3 can be at least partially, and entirely, flat. Additional surfaces to the third surface S3 can be added, so as to generate additional bearing surfaces between surfaces S1 and S2.

[0094] As illustrated for example in [Fig. 6], the third support surface S3 can be curved between the first support surface SI and the second support surface S2. Thus, and synergistically with a tilting of the device 1 actuated by a motor 231, the positioning of the device 1 in the cutting and analysis configurations can be chosen for any angle within a range delimited by the support positions on the SI and S2 surfaces.

[0095] Examples of dimensions are now given by way of non-limiting examples with reference to [Fig.2].

[0096] At least one of the first 100 and second 101 arms may have a thickness Dl, taken along the normal to the corresponding bearing surface, of substantially between 1 and 5 mm. The first 100 and second 101 arms may have the same thickness Dl.

[0097] The housing 110 can extend, depending on the direction of propagation of the ion beam 200, over a distance D2 of approximately between 0.5 and 4 mm. The distance D2 can be chosen according to the size of the sample 3 and / or the depth of cut achieved. Preferably, the distance D2 is limited to this maximum value in order to limit the cutting time and the curtain effect that may occur at the cutting surface 3a of the sample 3.

[0098] The housing may have a depth D3, measured along the normal to the second bearing surface S2, of approximately between 1 µm and 1 mm, preferably approximately equal to 150 µm. This depth may be chosen according to the dimension of the sample 3. Note that, as described in more detail later, this depth D3 may also be adjustable.

[0099] The rotational span of device 1 can be described by the distances D4, extending from the junction between the first 100 and second 101 arms to the housing 110, and D4', corresponding to the length of the first arm 100. These dimensions are preferably large enough to ensure retention by the tilting member 23, particularly when the tilting member 23 applies a force alternately to the faces 100a, 101a, and, where applicable, 102a, without risk of contacting the sample 3. For this reason, the distances D4 and D4' are substantially greater than or equal to 2 mm. Note that D4 and D4' are preferably, but not necessarily, equal to each other. In the case of rotation of device 1 actuated by a motor 231, these dimensions may be smaller.

[0100] The first arm 100 may have a total height D5, measured between the support surface S2 and the highest point of the first arm 100 when the device is resting on the support surface S2, of substantially less than or equal to 4 mm. The risk of touching the analyzer with the device 1 during SIMS analysis is thus limited.

[0101] The device 1 may also have a width D8, taken along the Y direction (illustrated for example in [Fig. 8A]), of substantially between 2 mm and 20 mm. This makes it possible to place several samples 3 side by side in one or more housings 110 or to cut a sample 3 having a significant width.

[0102] As illustrated, for example, in Figures 7A and 7B, the device 1 may include several compartments 110, each intended to hold a sample 3. According to the examples shown, these compartments 110 are preferably at least partially aligned along the propagation direction of the ion beam 200, or equivalently along the main extension direction of the first arm 101. Alternatively or in addition, compartments may be at least partially aligned along the transverse direction Y. The sample cutting step can thus be shared for several samples 3, and in particular precede the analysis of each sample. Each compartment 110 may have its own masking portion 111 and, more specifically, its own edge 1110.

[0103] As illustrated, for example, in [Fig. 7A], these housings can have substantially equal depths. Several samples with the same cutting depth can thus be produced in parallel. Alternatively, and as illustrated, for example, in [Fig. 7B], at least two of these housings 110, and preferably each housing 110, can have different depths D3a, D3b, D3c. Thus, several samples with different cutting depths can be produced in parallel.

[0104] The device 1 can be configured to cut the sample 3 at different depths in different locations within the same sample 3. Figures 8A to 8C describe several embodiments of the housing 110. The internal volume 1100 of the housing 110 can be partially delimited by a bottom 110b. The bottom 110b of the housing 110 can be substantially parallel to the second support surface S2 along the transverse direction Y ([Fig. 8A]). The cutting depth can be the same at different points in the sample 3. Alternatively, the bottom 110b can be at least partially oblique to the second support surface S2 along the transverse direction Y ([Fig. 8B]). According to another example, the bottom 110b can have reliefs 110ab arranged at different heights along the Z direction ([Fig. 8C]). These reliefs 1 lOab can be juxtaposed along the transverse direction Y.In other words, the bottom 110b can have several juxtaposed portions along the transverse direction Y, each portion having a different depth D3. According to these last two examples, sample 3 is thus arranged obliquely with respect to the transverse direction Y, which makes it possible to obtain different cutting depths at different points of sample 3.

[0105] The masking portion 111, and more particularly the edge 1110, can, alternatively or in addition, be configured so as to induce a cut of the sample 3 at a different depth in different locations of the same sample 3. Figures 9A to 9C describe several examples of embodiments of the masking portion 111, and more particularly of the edge 1110. In the following, we consider, by way of non-limiting The edge 1110. The described characteristics can nevertheless be applied to the upper surface 11 of the masking portion 111. The edge 1110 can be substantially parallel to the second support surface S2 along the transverse direction Y ([Fig. 9A]). The cutting depth can be the same at different points of the sample 3. Alternatively, the edge 1110 can be at least partially oblique to the second support surface S2 along the transverse direction Y ([Fig. 9B]). As another example, the edge 1110 can have reliefs 1110a arranged at different heights along the Z direction ([Fig. 9C]). These reliefs 1110a can be juxtaposed along the transverse direction Y. In other words, the edge 1110 can have several juxtaposed portions along the transverse direction Y; this portion forms a crenellated profile.According to these last two examples, the 200 ion beam will cut the sample 3 at several depths exposed to the 200 beam.

[0106] Note that in figures 8A to 9C, the housing 110 is delimited laterally along the transverse direction Y. It can be foreseen that the housing 110 is not delimited along the transverse direction Y, and in particular when the sample 3 is intended to be fixed in the housing as described above.

[0107] As illustrated, for example, by Figures 10A and 10B, the holding module 110 can be configured to adjust the portion of the sample 3 that will be masked from the ion beam 200. To this end, the depth D3 of the housing 110 can be adjusted and / or the height D7 of the masking portion, and in particular of the edge 1110, can be adjusted. As illustrated, for example, in [Fig. 1OA], the device 1 can include a component 112 configured to adjust the depth D3 of the housing 110. To this end, the component 112 can be configured to move the bottom 110b of the housing 110 along the normal to the second support surface S2. As illustrated for example in [Fig.1OB], device 1 may include, as an alternative or in addition, a member 112 configured to adjust the height D7 of the edge 1110. For this purpose, member 112 may be configured to move the masking portion 111 along the normal to the second support surface S2.The component 112 can, for example, be a micrometric device, such as a micrometric screw, or a spring.

[0108] Device 1 can be reused over several cutting and analysis cycles. For example, device 1 is made of metal. Device 1 can thus withstand a GCIB ion beam.

[0109] The manufacture of the device 1 may include the following steps. A part, for example a metal part, may be machined. The machining may be done by electrical discharge machining (EDM). The machining may be configured to form the two arms 100, 101 and the housing 110. The tilt angle, and where applicable the secondary tilt angles, may be custom-selected prior to machining, and in particular depending on the configuration of instrument 2. This eliminates the constraints imposed by the geometry of spectrometer 2.

[0110] The upper face of the retaining module 10 can then be polished to improve the quality of the surface obtained, which will be exposed to the ion beam 200. The depth D3 of the housing 110 can also be precisely adjusted.

[0111] The manufacturing process can then include machining the edge with plasma-FIB.

[0112] The manufacturing process may further include cutting the first arm 100 of the device 1, for example with a wire saw, to limit the distance D5 (see [Fig.2]).

[0113] The invention is not limited to the embodiments described above and extends to all embodiments covered by the invention. The present invention is not limited to the examples described above. Many other embodiments are possible, for example by combining features described above, without departing from the scope of the invention. Furthermore, the features described with respect to one aspect of the invention can be combined with another aspect of the invention.

Claims

Demands

1. A sample holder device (1) for cutting at least one sample (3) by an ion beam (200) and in situ analysis by secondary ion mass spectrometry, having a first configuration referred to as the "cutting" configuration in which the sample (3) is intended to be in a first position, and a second configuration referred to as the "analysis" configuration in which the sample (3) is intended to be in a second position, the first position being distinct from the second position, the device (1) being configured so as to rotate the sample (3) between the first position and the second position during the transition between the cutting configuration and the analysis configuration, the device (1) being characterized in that it comprises: • a pivot module (10) comprising at least two support surfaces (S1, S2, S3) defining between them, at the level of an axis of rotation (A1), a tilting angle α,the device being supported on one (S1, S3) of said support surfaces in the cutting configuration, and the device being supported on another (S3, S2) of said support surfaces in the analysis configuration, the device (3) being configured to be tilted in rotation about the axis of rotation (A1) during the transition between the cutting configuration and the analysis configuration, • a holding module (11) comprising: • a housing (110) configured to receive the sample (3), • a masking portion (111) configured to, in the cutting configuration, partially mask the sample (3) from the ion beam (200), when the sample (3) is placed in the housing (110).

2. Device (1) according to the preceding claim, wherein, in the cutting configuration, the masking portion (111) comprises at least one surface (111a) intended to be disposed obliquely with respect to the ion beam (200) to delimit at least one edge (1110) partially masking the sample (3) from the ion beam (200).

3. Device (1) according to any one of the preceding claims, wherein the tilt angle a is between 120° and 160°.

4. Device (1) according to any one of the preceding claims, wherein the pivot module (10) comprises a first arm (100) comprising a first bearing surface (S1) and a second arm (101) comprising a second bearing surface (S2), and wherein the retaining module (11) is disposed on the second arm (101), the retaining module (11) being further configured so that the housing (110) and the masking portion (111) are raised relative to the second arm (101).

5. Device (1) according to any one of the preceding claims, wherein the pivot module (10) comprises a third bearing surface (S3) disposed between a first (SI) and a second (S2) bearing surfaces, the third bearing surface (S3) defining, with each of the first (SI) and second (S2) bearing surfaces, a secondary tilting angle a2, a3.

6. Device (3) according to any one of the preceding claims, wherein the holding module (11) comprises a plurality of housings (110) each configured to accommodate a sample (3).

7. Device according to the preceding claim, wherein at least two dwellings (110) of the plurality of dwellings (110) have a different depth (D3) between them.

8. Device (1) according to any one of the preceding claims, wherein, in the cutting configuration, the device (1) is configured to cut the sample (3) at a different depth at different points of the sample (3): • the masking portion (111) being oblique and / or comprising reliefs (1110a) arranged at different heights from each other, and / or • the housing (110) having an oblique bottom (110b) and / or comprising reliefs (110ab) arranged at different heights from each other.

9. Device (1) according to any one of the preceding claims, further comprising a component (112) configured to modify at less a depth (D3) of the housing (110) and / or at least a height (D7) of the masking portion (111).

10. Instrument (2) for in situ analysis by secondary ion mass spectrometry comprising an ion beam gun (20), the instrument further comprising: • a sample-holding stage (22), • the sample-holding device (1) according to any one of the preceding claims, disposed on the sample-holding stage (22), • a so-called tilting member (23), configured to tilt the sample-holding device (1) between the cutting configuration and the analysis configuration.

11. Instrument (2) according to the preceding claim, wherein the pivot module (10) has a face opposite (100a, 101a, 102a) to each of the bearing surfaces (SI, S2, S3), and wherein the tilting member (23) is configured to alternately exert a force on one of said faces (100a, 101a, 102a), so as to maintain the device (1) respectively in the cutting configuration and in the analysis configuration.

12. Instrument (2) according to claim 10, wherein the tilting member (23) comprises a motor (231) configured to tilt the device (1) between the cutting configuration and the analysis configuration.

13. A method for cutting and in-situ analysis by secondary ion mass spectrometry of a sample (3), comprising: • a disposition of a sample (3) in a sample holder device (1) comprising a holding module (11), the holding module (11) comprising a housing (110) configured to accommodate the sample (3), • the device (1) comprising a pivot module (10) comprising at least two bearing surfaces (S1, S2, S3) defining between them, at the level of an axis of rotation (A1), a tilt angle α, an disposition of the device (1) housing the sample (3) on the sample holder stage (22) of an instrument (2) for in-situ analysis by secondary ion mass spectrometry, such that the device (1) is in a first configuration referred to as

14.

15. cutout in which the device rests on one (SI, S3) of said support surfaces, • in the cutting configuration, a cutting of the sample (3) by an ion beam (200), in which the sample (3) in the housing (110) is partially masked from the ion beam (200) by a masking portion (111) of the holding module (11), so as to expose after cutting a cross-sectional surface (3a) of the sample (3), • a transition of the device (1) from the cutting configuration to a second configuration called the analysis configuration, by rotating the device (1) around the axis of rotation (Al) so as to place the device (1) in contact with another (S2, S3) of said support surfaces, • a mass spectrometry analysis of secondary ions of the exposed cross-sectional surface (3a) of the sample. A method according to the preceding claim, further comprising, prior to cutting the sample (3), cooling the sample (3) to a temperature less than or equal to -140°C. A method according to any one of the two preceding claims, wherein the sample (3) is a biological and / or organic sample.

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