WO2019217873A1

WO2019217873A1 - Sample support with fiducial indicia

Info

Publication number: WO2019217873A1
Application number: PCT/US2019/031802
Authority: WO
Inventors: Ian Patrick Wellenius; John Damiano Jr.
Original assignee: Protochips, Inc.
Priority date: 2018-05-10
Filing date: 2019-05-10
Publication date: 2019-11-14

Abstract

Sample support structure for electron microscopy comprises a substrate base having at least one aperture formed therethrough, a film mounted on the substrate such that a window portion of the film covers the aperture, and at least one fiducial mark on the film or substrate base for identification of an electron microscopy sample. Holes may be formed through the window portion of the film for mounting of samples, and sample-identification fiducial marks may be in proximity respectively with the holes. The aperture can be a slot extending along a length axis, with multiple holes being regularly spaced along the length axis, and the multiple sample-identification fiducial marks being offset from and aligned with the multiple holes in one-to-one correspondence.

Description

SAMPLE SUPPORT WITH FIDUCIAL INDICIA

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of priority of U.S. provisional patent application no.

62/669,411, titled“Sample Support with Fiducial Indicia,” filed on May 10, 2018, which is

incorporated herein in its entirety by this reference.

TECHNICAL FIELD

[0002] The present disclosure relates to sample support structures for electron microscopy. More particularly, the present disclosure relates to sample support structures having fiducial marks discernible at multiple levels of view magnification and multiple microscopy methods.

BACKGROUND

[0003] Electron microscopy is being conducted on smaller and smaller material and device samples, and increasingly time efficiency is needed to process multiple samples in testing procedures for which each sample must be positively identified for correlation with specific characterization results such as imaging.

[0004] Industrial users of electron microscopy, where scanning electron microscopy (SEM) was previously sufficient, are increasingly turning to higher resolution transmission electron microscopy (TEM) and scanning TEM (STEM) as well or instead. In some TEM sample preparation processes, samples only several microns across are cut by FIB from structures such as semiconductor wafers where processors and other small devices are formed and require characterization, imaging, or analysis. The samples are typically mounted on holey carbon grids for electron microscopy. Their mounting, identification, and analysis are unsatisfactorily dependent upon manual handling and data-to-sample correlation. [0005] As the features under analysis grow smaller, for example for nanoscale features, SEM techniques are increasingly insufficient, and higher resolution TEM is needed. With increasing need for time-efficient processes, which are expected to be more and more automated, rapid processing of multiple uniquely identified samples is needed.

SUMMARY

[0006] This summary is provided to introduce in a simplified form concepts that are further described in the following detailed descriptions. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it to be construed as limiting the scope of the claimed subject matter.

[0007] Disclosed herein is a sample support structure for electron microscopy. The sample support structure comprises a substrate base having at least one aperture formed therethrough. The sample support structure further comprises a film mounted on the substrate such that a window portion of the film covers the aperture; and at least one fiducial mark on the film or substrate base for identification or positioning confirmation.

[0008] According to one or more embodiments, at least one hole is formed through the window portion of the film for mounting a sample.

[0009] According to one or more embodiments, multiple holes are formed through the window portion of the film for mounting respective multiple samples, and multiple sample-identification fiducial marks are formed in proximity respectively with the multiple holes.

[00010] According to one or more embodiments, the sample support structure further includes at least one chiral fiducial mark. [00011] According to one or more embodiments, the aperture is a slot extending along a length axis; the multiple holes are regularly spaced along the length axis; and, the multiple sample- identification fiducial marks are offset from and aligned with the multiple holes in one-to-one correspondence.

[00012] According to one or more embodiments, the aperture is a slot that tapers to a slit at the window portion of the film.

[00013] According to one or more embodiments, the sample support structure further includes multiple targeting fiducial marks.

[00014] According to one or more embodiments, at least one fiducial mark is positioned on the window portion of the film, and at least one fiducial mark is positioned off the window portion of the film.

[00015] According to one or more embodiments, the sample support structure further comprises a recess formed on a bottom side of the substrate, the bottom side opposite to the film mounted side of the substrate.

[00016] According to one or more embodiments, a portion of the substrate separates the recess from the film.

[00017] According to one or more embodiments, the at least chiral fiducial mark includes two or more distinct geometric figures.

[00018] According to one or more embodiments, a first geometric figure is separated from a second geometric figure by a distance.

[00019] According to one or more embodiments, the first geometric figure has a first perimeter, and wherein the second geometric figure has a second perimeter different from the first perimeter.

[00020] According to one or more embodiments, the film comprises silicon nitride.

[00021] According to one or more embodiments, the window portion of the film is peripherally supported by the substrate material.

[00022] According to one or more embodiments, the substrate comprises silicon, wherein the slot tapers at an angle defined by a 111 plane of a silicon crystal lattice.

[00023] According to one or more embodiments, the slot is formed by etching the substrate, wherein the substrate comprises silicon, wherein the slot tapers at an angle of approximately 54.7 degrees.

[00024] According to one or more embodiments, the at least one fiducial mark comprises one or more of numbers, letters and graphics.

[00025] According to one or more embodiments, the at least one fiducial mark comprises one or more of barcodes and QR codes.

[00026] According to one or more embodiments, the at least one fiducial mark is readable by a human operator or an image processing mechanism.

[00027] According to one or more embodiments, the at least one fiducial mark is positioned on the window portion of the film.

[00028] According to one or more embodiments, the at least one fiducial mark is positioned proximal to the window portion of the film.

[00029] According to one or more embodiments, the at least one fiducial mark is configured to be visible in one or more of transmission electron microscopy (TEM) imaging and scanning transmission electron microscopy (STEM) imaging.

[00030] According to one or more embodiments, the at least one fiducial mark is configured to be visible in scanning electron microscopy (SEM) imaging.

[00031] According to one or more embodiments, the multiple targeting fiducial marks are aligned with edges of a chip formed in the substrate to identify one or more of a chip shape or a chip configuration.

[00032] According to one or more embodiments, the multiple holes are arranged in a single row.

[00033] According to one or more embodiments, the multiple sample-identification fiducial marks are arranged in a single row.

[00034] According to one or more embodiments, the chiral fiducial mark is positioned at an approximate geometric center of the window portion of the film.

[00035] According to one or more embodiments, the at least one fiducial mark is configured to be visible in one or more of: transmission electron microscopy (TEM) imaging, scanning transmission electron microscopy (STEM) imaging, and scanning electron microscopy (SEM) imaging.

[00036] According to one or more embodiments, the at least one fiducial mark is configured for recognition by one or more of: a human operator and an automated image recognition and processing mechanism.

[00037] Disclosed herein is a sample support structure for electron microscopy comprising: a substrate for mounting a sample thereon, the substrate having at least one aperture extending from a substrate bottom surface towards a substrate top surface; a film formed on the substrate top surface such that a window portion of the film covers the aperture; and at least one fiducial mark formed on the film for identification of the sample.

[00038] According to one or more embodiments, the aperture is formed by pattern etching substrate material from the substrate bottom surface towards the substrate top surface.

[00039] According to one or more embodiments, the film is formed by growing a silicon nitride film on the substrate top surface.

[00040] According to one or more embodiments, the silicon nitride film is formed as an amorphous film.

[00041] According to one or more embodiments, the aperture is formed after the silicon nitride film is formed.

[00042] According to one or more embodiments, at least one hole is formed through the window portion of the film for mounting the sample.

[00043] According to one or more embodiments, the aperture and the hole are configured for transmitting an electron beam therethrough.

[00044] According to one or more embodiments, the at least one fiducial mark identifies a sample site.

[00045] According to one or more embodiments, the at least one fiducial mark is formed by etching through an entire thickness of the film.

[00046] According to one or more embodiments, the at least one fiducial mark is formed by etching a top portion of the film. [00047] Disclosed herein is a sample support structure for electron microscopy comprising a substrate having at least one aperture extending from a bottom substrate surface towards a top substrate surface; a film mounted on the substrate top surface such that a window portion of the film covers the aperture; at least one hold formed through the window portion for mounting a sample; and at least one fiducial mark formed on the film for positioning confirmation of the sample.

BRIEF DESCRIPTION OF THE DRAWINGS

[00048] The previous summary and the following detailed descriptions are to be read in view of the drawings, which illustrate particular exemplary embodiments and features as briefly described below. The summary and detailed descriptions, however, are not limited to only those embodiments and features explicitly illustrated.

[00049] The embodiments illustrated, described, and discussed herein are illustrative of the present invention. As these embodiments of the present invention are described with reference to illustrations, various modifications or adaptations of the methods and or specific structures described may become apparent to those skilled in the art. It will be appreciated that modifications and variations are covered by the above teachings and within the scope of the appended claims without departing from the spirit and intended scope thereof. All such modifications, adaptations, or variations that rely upon the teachings of the present invention, and through which these teachings have advanced the art, are considered to be within the spirit and scope of the present invention. Hence, these descriptions and drawings should not be considered in a limiting sense, as it is understood that the present invention is in no way limited to only the embodiments illustrated.

[00050] FIG. 1 is a top plan view of a sample support structure according to at least one embodiment. [00051] FIG. 2 is a cross-sectional elevation view of the sample support structure taken along the line 2-2 in FIG. 1.

[00052] FIG. 3 is a bottom plan view of the sample support structure of FIG. 1.

[00053] FIG. 4 is an enlarged top view of a portion of the sample support structure of FIG. 1.

[00054] FIG. 5 is a top perspective view of a sample support structure according to at least one embodiment.

[00055] FIG. 6 is a bottom perspective view of a sample support structure of FIG. 4.

[00056] FIG. 7 is a top view of a sample support structure according to at least one embodiment.

[00057] FIG. 8 is an enlarged top view of a portion of the sample support structure of FIG. 7.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[00058] Below, the technical solutions in the examples of the present invention are depicted clearly and comprehensively with reference to the figures according to the examples of the present invention. Obviously, the examples depicted here are merely some examples, but not all examples of the present invention. In general, the components in the examples of the present invention depicted and shown in the figures herein can be arranged and designed according to different configurations. Thus, detailed description of the examples of the present invention provided in the figures below are not intended to limit the scope of the present invention as claimed, but merely represent selected examples of the present invention. On the basis of the examples of the present invention, all of other examples that could be obtained by a person skilled in the art without using inventive efforts will fall within the scope of protection of the present invention.

[00059] These descriptions are presented with sufficient details to provide an understanding of one or more particular embodiments of broader inventive subject matters. These descriptions expound upon and exemplify particular features of those particular embodiments without limiting the inventive subject matters to the explicitly described embodiments and features. Considerations in view of these descriptions will likely give rise to additional and similar embodiments and features without departing from the scope of the inventive subject matters. Although the term“step” may be expressly used or implied relating to features of processes or methods, no implication is made of any particular order or sequence among such expressed or implied steps unless an order or sequence is explicitly stated.

[00060] Any dimensions expressed or implied in the drawings and these descriptions are provided for exemplary purposes. Thus, not all embodiments within the scope of the drawings and these descriptions are made according to such exemplary dimensions. The drawings are not made necessarily to scale. Thus, not all embodiments within the scope of the drawings and these descriptions are made according to the apparent scale of the drawings with regard to relative dimensions in the drawings. However, for each drawing, at least one embodiment is made according to the apparent relative scale of the drawing.

[00061] Like reference numbers used throughout the drawings depict like or similar elements.

Unless described or implied as exclusive alternatives, features throughout the drawings and

descriptions should be taken as cumulative, such that features expressly associated with some particular embodiments can be combined with other embodiments. The present invention will be further described with reference to the accompanying drawings.

[00062] A sample support structure for electron microscopy includes a substrate base having at least one aperture, a film mounted on the substrate such that a window portion of the film covers the aperture, and at least one fiducial mark on the film or substrate base for identification or positioning confirmation. Holes may be formed through the window portion of the film for mounting of samples, and sample-identification fiducial marks may be in proximity respectively with the holes. One or more chiral fiducial marks may be provided. The aperture can be a slot extending along a length axis, with the multiple holes being regularly spaced along the length axis, and the multiple sample-identification fiducial marks being offset from and aligned with the multiple holes in one-to-one correspondence.

The aperture may be a slot that tapers to a slit at the window portion of the film. There may be multiple targeting fiducial marks. At least one fiducial mark can be positioned on the window portion of the film, and at least one fiducial mark can be positioned off the window portion of the film.

[00063] A sample support structure 100, according to at least one embodiment, is shown in FIG. 1. The sample support structure 100 is shown as a chip that includes a substrate die 110 serving as a base for rigidity, manipulation, and mounting of the structure 100 in an electron microscope and other fixtures when preparing samples. A film 120 shown as a top layer covers an upper face of the substrate die 110. The sample support structure 100 has a top surface 102 defined in the illustrated embodiment by the upper surface of the film 120, and a bottom surface 104 defined by the opposite side of the die 110.

[00064] The substrate die 110 is a generally planar structure having apertures shown as tapered slots 112 formed therethrough for electron beam transmission. The slots are wider and longer along the bottom surface 104 and taper to define narrowed top slits at the top surface of the substrate. The top slits are covered or spanned by the film 120, such that the film 120 defines a respective membrane window 122 above the top slit of each slot 112, each window 122 being only peripherally supported by the substrate die 110.

[00065] The substrate die 110 can be fabricated, for example, of silicon. The film 120 may be, for example, a silicon nitride film. In at least one embodiment, the film 120 is formed of LPCVD silicon nitride. Silicon nitride is typically a tensile, amorphous film, which makes it advantageous for sample support applications. The structure 100 can be formed by growing a silicon nitride film on the top side of a thicker silicon substrate, then pattern etching away substrate material from the side of die opposite the film. The substrate is etched at the locations of the slots 112 such that adjacent portions of the substrate die 110 effectively frame the windows 122. As the etching process deepens an etch cavity from the bottom surface 104, the cavity tapers thus forming the tapered slots 112. The tapered angle, defined by the 111 plane of the silicon crystal lattice, is well characterized angle (54.7 degrees) for wet- etched silicon wafers. Thus, the dimensions of the top slits at the windows 122 are governed by the tapered angle and the etch pattern dimensions at the etch initiation surface 104.

[00066] As shown in the enlarged view of FIG. 4, holes 124 are formed through the window portions 122 of the film 120 (FIG. 2) for placement of samples and high electron beam transmissivity. This may be particularly advantageous, for example, for TEM analysis of samples. In the illustrated embodiment of the sample support structure 100, multiple holes 124A-124D are regularly spaced along the window 122 as sample sites along the length axis 128 of the rectangular window 122. This advantageously facilitates the placement of multiple samples along the window at the locations of the holes 124A-124D. Thus, high throughput processing of samples is facilitated because each loading and use of the sample support structure 100 can include multiple discrete samples.

[00067] Advantageously, to facilitate identification of each particular sample support structure

100, and to further particularly identify each sample site, fiducial marks are provided. The fiducial marks can be formed, for example, by etching on, into, or through the film 120 top layer. The fiducial marks can be formed as any desired or useful indicia, including individual numbers, letters and series and combinations thereof, and graphics. Other non-exclusive examples in include barcodes, QR codes, other codes, and indicia formats that are either readable by human operator, machine, or both.

[00068] Features etched into the silicon nitride can be formed on the window portions 122 of the film 120 that span the top slits of the tapered slots 112, and off ihc window portions. The difference between on-window and off- window locations is to be considered with regard to the chip in use as a sample support. Features on the window portions will be visible in an optical microscope, in SEM imaging, and in TEM/STEM imaging. Features off the window portions will be visible in an optical microscope and in SEM imaging, but not in TEM/STEM imaging because the silicon substrate will block transmission of electrons. The precise relative locations of on- window and off- window features are to be prescribed or predetermined, and these features may be formed in the same process step.

[00069] For example, an off-window identification fiducial mark 106 is shown in FIG. 1 as an ID label viewable upon the top surface 102 for identification of the particular sample support 100.

Thus, each sample support structure 100 can be identified as a unique item, as a member of a set or group, as within a category, or for use as desired. In the illustrated embodiment, the identification fiducial mark 106 is shown as an off-window feature. On-window identification fiducial marks may be provided in addition to or in lieu of the off-window mark.

[00070] For further advantage, for example with respect to registering or locating each sample support structure 100, targeting fiducial marks 108 (FIG. 1) are provided. For example, off-window targeting fiducial marks 108 are shown as crosses, each with two line segments, which are aligned respectively with the linear edges of the rectangular chip. The targeting fiducial marks 108 may be patterned to resemble or identify the chip shape or configuration, for example as rectangular as shown in FIG. 1. In the illustrated embodiment, the targeting fiducial marks 108 are shown as off-window features. On- window targeting fiducial marks may be provided in addition to or in lieu of the off- window marks.

[00071] For further example, sample-level identification fiducial marks 126 are shown as on- window features along the window 122 in FIG. 4 in proximity to respective sample sites, which are shown as holes 124. In the illustrated embodiment, a single row or column of sample-site holes 124 is shown, and a corresponding single column or row of sample-level identification marks 126 is shown. The sample-level identification marks 126 are shown in one-to-one correspondence and as aligned with the sample-site holes 124 for identification of each sample site and any sample mounted there. Thus, each particular hole 124A-124D is identified by a respective identification mark 126A-126D.

[00072] Additionally, one or more chiral fiducial marks may be provided. A sample-level chiral fiducial mark 130 is shown in FIG. 4 for example as an on-window feature. A chiral mark is asymmetric in such a way that the mark and its mirror image are not superimposable, particularly with regard in the illustrated example to a mirror image taken by flipping about the length axis 128 of the rectangular window 122. The chiral fiducial mark 130 may be used to confirm placement and orientation of the sample support structure 100. Advantageously the chiral fiducial mark 130 is placed at the approximate geometrical center of the window 122 in the illustrated example so as to provide its appearance, whether central or peripheral, in views taken from multiple view magnifications and image locations. Chiral fiducial mark 130 can take other geometric shapes besides the shape illustrated in FIG. 4.

[00073] Each of the fiducial marks described herein may be used to confirm identity, placement, and orientation. For example, the off-window chip-level identification fiducial mark 106 and targeting fiducial marks 108 (FIG. 1) may be particularly useful when viewing the sample support structure 100 and any samples mounted thereon with an optical microscope and with SEM imaging. The on-window sample-level identification fiducial marks 126 and chiral mark fiducial mark 130 are useful when viewing the sample support structure 100 and any samples mounted thereon using optical, SEM and TEM/STEM imaging. Thus, the sample support structure 100 provides fiducial marks discernible in multiple microscopy resolution regimes (optical, SEM, TEM/STEM).

[00074] Advantageously, the fiducial marks, in various embodiments, are located and oriented to facilitate both human-operator and automated recognition and confirmation, in which image processing of digital images taken is conducted by computerized methods. For example, both the chip-level fiducial marks (106, 108) and sample-level or window-level fiducial marks (126, 130) can be used by automated image-recognition processes. Fiducial marks in the illustrated embodiment are provided on- window and off-window at predetermined or prescribed locations to facilitate the correlation of sample and location information gathered in TEM/STEM imaging with sample and location information gathered in optically and SEM imaging.

[00075] Three windows (122, FIG. 1), each having eight sample sites (holes 124, FIG. 4) are explicitly shown in the illustrated embodiment. Other examples and configurations are within the scope of these descriptions. Each window can have a unique mark, shape, and location.

[00076] In use, samples can be placed over the holes 124 and imaged in the SEM, TEM, and/or STEM to obtain high-resolution images of the samples. The identification of each sample can be traced through the entire sample deposition and imaging workflow by correlating the support ID and sample location on the support to the resulting image files.

[00077] A sample support structure 200, according to one or more embodiments, is shown in FIGS. 5 and 6. FIGS. 5 and 6 illustrate three-dimensional views of sample structure 200. The sample support structure 200 may include the same or similar attributes as sample support structure 100 described earlier, except as provided below. Sample support structure 200 includes recess 132 extending inwards from the bottom surface 104. Recess 132 is formed by etching away substrate material from the side of the die opposite film 120. In one embodiment, a portion of substrate die 100 separates recess 132 from the film 120. Recess 132 advantageously introduces asymmetry to the structure such that sample support structure 200 does not have the same bottom profile when it is rotated 180° about an axis running perpendicular to the major surface of sample support structure 200. This can advantageously assist in better processing of samples as multiple discrete samples are characterized, imaged, or otherwise analyzed.

[00078] A further sample support structure 300, according to one or more embodiments, is shown in FIGS. 7 and 8. Sample support structure 300 can include the same or similar attributes as sample support structures 100 and 200 described earlier, except as provided below. Sample support structure 300 includes chiral fiducial mark 230, as illustrated, for example, in FIG. 8. As shown in FIG. 8, chiral fiducial mark 230 roughly takes the form of two exclamation points side-by-side in one embodiment. In the FIG. 8 embodiment, chiral fiducial mark 230 includes four distinct geometric figures. In some embodiments, chiral fiducial mark 230 can include two or more distinct geometric figures. In one embodiment, at least one geometric figure can have a smaller perimeter relative to remaining geometric figures. In the same or in different embodiments. The geometric figure of a first perimeter value can be separated from a geometric figure of second perimeter value by a distance, wherein the first perimeter value can be different from the second perimeter value.

[00079] As a comparison of chiral fiducial mark 230 of FIG. 8 with chiral fiducial mark 130 illustrated in FIG. 4 makes clear, chiral fiducial mark 230 can advantageously allow for an alternate technique for confirming placement and orientation of the sample support structure 300.

[00080] Chiral fiducial mark 230 advantageously introduces asymmetry to the structure such that such a way that the mark and its mirror image are not superimposable, particularly with regard in the illustrated example to a mirror image taken by flipping about the breadth axis 328 of the rectangular window 122, for example. In one embodiment, chiral fiducial mark 230 is placed at the approximate geometrical center of the window 122 so as to provide its appearance, whether central or peripheral, in views taken from multiple view magnifications and image locations. Chiral fiducial mark 230 can be provided on-window and / or off- window at predetermined or prescribed locations to facilitate the correlation of sample and location information gathered in TEM/STEM imaging with sample and location information gathered in optically and SEM imaging. Even though only 124A is marked in FIG. 8), in one or more embodiments, chiral fiducial mark 230 can advantageously facilitate the placement of multiple samples along the window at the locations of the holes such as 124A-124D.

[00081] Chiral fiducial mark 230 can take other forms and shapes besides the form illustrated in FIG. 8. Chiral fiducial mark 230 can also be positioned in other locations. Chiral fiducial mark 230 can also be positioned on window or off window. Accordingly, several other forms of chiral fiducial and several positioning locations for the chiral fiducial marks are contemplated by the invention as described herein.

[00082] Particular embodiments and features have been described with reference to the drawings. It is to be understood that these descriptions are not limited to any single embodiment or any particular set of features, and that similar embodiments and features may arise or modifications and additions may be made without departing from the scope of these descriptions and the spirit of the appended claims. [00083] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms“a,”“an” and“the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms“comprises” and/or“comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

[00084] The descriptions of the various embodiments of the present invention have been presented for purposes of illustration, but are not intended to be exhaustive or limited to the

embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein was chosen to best explain the principles of the embodiments, the practical application or technical improvement over technologies found in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.

[00085] The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.

[00086] These and other changes can be made to the disclosure in light of the Detailed

Description. While the above description describes certain embodiments of the disclosure, and describes the best mode contemplated, no matter how detailed the above appears in text, the teachings can be practiced in many ways. Details of the system may vary considerably in its implementation details, while still being encompassed by the subject matter disclosed herein. As noted above, particular terminology used when describing certain features or aspects of the disclosure should not be taken to imply that the terminology is being redefined herein to be restricted to any specific characteristics, features, or aspects of the disclosure with which that terminology is associated. In general, the terms used in the following claims should not be construed to limit the disclosure to the specific embodiments disclosed in the specification, unless the above Detailed Description section explicitly defines such terms. Accordingly, the actual scope of the disclosure encompasses not only the disclosed

embodiments, but also all equivalent ways of practicing or implementing the disclosure under the claims.

Claims

CLAIMS What is claimed is:

1. A sample support structure for electron microscopy, the sample support structure comprising: a substrate base having at least one aperture formed therethrough;

a film mounted on the substrate such that a window portion of the film covers the aperture; and at least one fiducial mark on the film or substrate base for identification or positioning

confirmation.

2. The sample support structure of claim 1, wherein at least one hole is formed through the

window portion of the film for mounting a sample.

3. The sample support structure of claim 1, wherein multiple holes are formed through the window portion of the film for mounting respective multiple samples, and

wherein multiple sample-identification fiducial marks are in proximity respectively with the multiple holes.

4. The sample support structure of claim 3, further including at least one chiral fiducial mark.

5. The sample support structure of claim 3, wherein:

the aperture is a slot extending along a length axis;

the multiple holes are regularly spaced along the length axis; and,

the multiple sample-identification fiducial marks are offset from and aligned with the multiple holes in one-to-one correspondence.

6. The sample support structure of claim 1, wherein the aperture is a slot that tapers to a slit at the window portion of the film.

7. The sample support structure of claim 1, comprising multiple targeting fiducial marks.

8. The sample support structure of claim 1, wherein at least one fiducial mark is positioned on the window portion of the film, and at least one fiducial mark is positioned off the window portion of the film.

9. The sample support structure of claim 1, further comprising a recess formed on a bottom side of the substrate, the bottom side opposite to the film mounted side of the substrate.

10. The sample support structure of claim 9, wherein a portion of the substrate separates the recess from the film.

11. The sample support structure of claim 4, wherein the at least chiral fiducial mark includes two or more distinct geometric figures.

12. The sample support structure of claim 11, wherein a first geometric figure is separated from a second geometric figure by a distance.

13. The sample support structure of claim 12, wherein the first geometric figure has a first perimeter, and wherein the second geometric figure has a second perimeter different from the first perimeter.

14. The sample support structure of claim 1, wherein the film comprises silicon nitride.

15. The sample support structure of claim 1, wherein the window portion of the film is peripherally supported by the substrate material.

16. The sample support structure of claim 6, wherein the substrate comprises silicon, wherein the slot tapers at an angle defined by a 111 plane of a silicon crystal lattice.

17. The sample support structure of claim 6, wherein the slot is formed by etching the substrate, wherein the substrate comprises silicon, wherein the slot tapers at an angle of approximately 54.7 degrees.

18. The sample support structure of claim 1, wherein the at least one fiducial mark comprises one or more of numbers, letters and graphics.

19. The sample support structure of claim 1, wherein the at least one fiducial mark comprises one or more of barcodes and QR codes.

20. The sample support structure of claim 1, wherein the at least one fiducial mark is readable by a human operator or an image processing mechanism.

21. The sample support structure of claim 1, wherein the at least one fiducial mark is positioned on the window portion of the film.

22. The sample support structure of claim 1, wherein the at least one fiducial mark is positioned proximal to the window portion of the film.

23. The sample support structure of claim 1, wherein the at least one fiducial mark is configured to be visible in one or more of transmission electron microscopy (TEM) imaging and scanning transmission electron microscopy (STEM) imaging.

24. The sample support structure of claim 1, wherein the at least one fiducial mark is configured to be visible in scanning electron microscopy (SEM) imaging.

25. The sample support structure of claim 7, wherein the multiple targeting fiducial marks are aligned with edges of a chip formed in the substrate to identify one or more of a chip shape or a chip configuration.

26. The sample support structure of claim 5, wherein the multiple holes are arranged in a single row.

27. The sample support structure of claim 5, wherein the multiple sample-identification fiducial marks are arranged in a single row.

28. The sample support structure of claim 4, wherein the chiral fiducial mark is positioned at an approximate geometric center of the window portion of the film.

29. The sample support structure of claim 1, wherein the at least one fiducial mark is configured to be visible in one or more of: transmission electron microscopy (TEM) imaging, scanning transmission electron microscopy (STEM) imaging, and scanning electron microscopy (SEM) imaging.

30. The sample support structure of claim 1, wherein the at least one fiducial mark is configured for recognition by one or more of: a human operator and an automated image recognition and processing mechanism.

31. A sample support structure for electron microscopy, comprising:

a substrate for mounting a sample thereon, the substrate having at least one aperture extending from a substrate bottom surface towards a substrate top surface;

a film formed on the substrate top surface such that a window portion of the film covers the aperture; and

at least one fiducial mark formed on the film for identification of the sample.

32. The sample support structure of claim 31, wherein the aperture is formed by pattern etching substrate material from the substrate bottom surface towards the substrate top surface.

33. The sample support structure of claim 31, wherein the film is formed by growing a silicon nitride film on the substrate top surface.

34. The sample support structure of claim 33, wherein the silicon nitride film is formed as an

amorphous film.

35. The sample support structure of claim 33, wherein the aperture is formed after the silicon nitride film is formed.

36. The sample support structure of claim 31, wherein at least one hole is formed through the

window portion of the film for mounting the sample.

37. The sample support structure of claim 36, wherein the aperture and the hole are configured for transmitting an electron beam therethrough.

38. The sample support structure of claim 31, wherein the at least one fiducial mark identifies a sample site.

39. The sample support structure of claim 31, wherein the at least one fiducial mark is formed by etching through an entire thickness of the film.

40. The sample support structure of claim 31, wherein the at least one fiducial mark is formed by etching a top portion of the film.

41. A sample support structure for electron microscopy, comprising:

a substrate having at least one aperture extending from a bottom substrate surface towards a top substrate surface;

a film mounted on the substrate top surface such that a window portion of the film covers the aperture;

at least one hold formed through the window portion for mounting a sample; and

at least one fiducial mark formed on the film for positioning confirmation of the sample.