Circular Mo Nanogrid Sample Support with Dual Si Post Structures on Upper and Lower Sides

Abstract

The present invention relates to a circular molybdenum nanogrid sample support having an upper and lower dual silicon post structure and belongs to the field of high-precision sample support technology used in electron microscope analysis equipment. The sample support of the present invention has a structure in which two circular molybdenum (Mo) bodies are precisely interlocked and joined, and within this structure, silicon (Si) posts of various shapes are arranged at the upper and lower portions, respectively. Through this upper and lower dual silicon post structure, two samples can be simultaneously fixed and TEM, SEM, or FIB analysis can be performed using a single loading process, thereby maximizing analysis efficiency. Furthermore, the uppermost portion of the silicon posts can be processed into a flat or D-cut shape; this D-cut shape may or may not penetrate downwards, and allows for uniform or non-uniform shape distribution between the posts, enabling adaptation to various sample shapes and analysis purposes. The circular molybdenum nanogrid sample support of the present invention simultaneously secures high mechanical strength and conductivity, and enables precise mass production through semiconductor process-based MEMS technology. Thus, the present invention provides excellent technical effects in terms of simultaneous analysis of multiple samples, reduction of background noise, reprocessing of samples, and compatibility with various analytical instruments.

Description

Technology Field

[0001] The present invention relates to a nanogrid support for fixing and analyzing a sample in an electron microscope analysis device, and more specifically, to a technology for a high-precision sample support applicable to TEM or SEM equipment, comprising a circular nanogrid support in which two molybdenum (Mo) bodies are interlocked and joined together, and including silicon posts of various shapes disposed at the top and bottom respectively inside the nanogrid support, thereby enabling simultaneous analysis of two samples in a single loading process, improving analysis efficiency, reducing background noise, and improving FIB processing efficiency. Background Technology

[0002] Sample analysis techniques using electron microscope analysis equipment, particularly TEM (Transmission Electron Microscope) or SEM (Scanning Electron Microscope), are widely used for high-precision observation and processing of samples at the nanoscale. For such analysis, a sample support capable of stably fixing the sample is essential, and among these, the development of a nanogrid support capable of accurately supporting nanometer-sized, thinned samples is crucial. Conventionally, mesh-type supports or silicon wafer-based sample holders have been primarily used, but various problems have been pointed out, such as insufficient precision in sample fixation, background noise generation, limitations in additional sample processing, and reduced reproducibility. In particular, since analysis must be performed with only a single sample loaded, when multiple samples are required for analysis, the loading and unloading processes of the equipment are repeated, leading to increased analysis time and reduced efficiency.

[0003] For example, Japanese published patent application JP2003-035682A discloses a sample holder in which a sample fixing part capable of fixing multiple samples is integrally formed, and includes a stepped sample fixing part suitable for ion beam processing. In addition, U.S. patent US10,338,126B2 describes a technique for stably fixing a sample to a sample support and applying it to FIB processing and TEM analysis.

[0004] However, most of these prior art technologies have structural limitations, such as the sample fixing part existing in a single direction or on a single plane, background noise occurring due to mesh structures or thick support structures, and the need to additionally mount a separate sample stand when analyzing multiple samples. Furthermore, conventional mesh-based supports have the disadvantage that it is difficult to handle and secure strength when processed into a thin structure, and silicon wafer-based sample stands are difficult to mass-produce due to the dicing process that requires skilled manual labor.

[0005] Therefore, there is a need to develop nanogrid support technology that is based on a high-strength structure using a molybdenum body, allows for the simultaneous fixation and analysis of two samples on a single nanogrid support by placing silicon posts on the top and bottom respectively, enables stable fixation and reprocessing of samples using silicon posts of various shapes, and is compatible with TEM or SEM equipment. The problem to be solved

[0006] The present invention was devised to solve the problems of the aforementioned conventional technology and aims to provide a nanogrid support technology that is based on a high-strength structure using a molybdenum body, allows for the simultaneous fixation and analysis of two or more samples on a single nanogrid sample support by arranging silicon posts at the top and bottom respectively, enables stable fixation and reprocessing of samples using silicon posts of various shapes, and is linked with TEM or SEM equipment. means of solving the problem

[0007] To solve the above problem, the present invention provides a nanogrid sample support having an upper and lower dual silicon post structure, wherein two circular molybdenum (Mo) bodies are interlocked and combined to form a single circular nanogrid support, and one or more silicon (Si) posts are installed at the top and bottom respectively inside the circular nanogrid support, and the silicon posts are formed in various shapes to fix a sample, and the nanogrid support is configured to simultaneously analyze multiple samples by utilizing the upper and lower silicon posts respectively in a single loading process.

[0008] Preferably, each of the molybdenum bodies is made of a high-strength metal having a high density and may have conductivity to prevent charge during electron microscope analysis.

[0009] Preferably, the molybdenum body can be formed into a small structure with a diameter of 3 mm or less and a thickness of 100 μm or less to facilitate handling.

[0010] Preferably, the uppermost part of the upper or lower silicone post may be configured with a D-cut shape where a flat surface and a vertical cutting surface meet, and such D-cut shape may or may not penetrate downward, and the plurality of silicone posts may be uniform or non-uniform.

[0011] Preferably, the width of the upper and lower silicon posts may be in the range of 100 nm to 10 µm, and the height may be in the range of 1 µm to 50 µm, and the silicon posts may be MEMS structures formed by semiconductor process technology.

[0012] Preferably, the silicon posts are arranged on the same plane and can be designed so that samples of various shapes can be mounted on the top of individual posts.

[0013] Preferably, the nanogrid sample support can be utilized in TEM, FIB, or SEM analysis processes after sample mounting.

[0014] Preferably, the nanogrid sample support comprises a plurality of silicon posts of different shapes, and the posts of different shapes can be selectively used depending on the size of the sample or the purpose of analysis.

[0015] Preferably, the top of the upper or lower silicon post can be formed through cutting (FIB D-cut). Effects of the invention

[0016] The nanogrid sample support according to the present invention is composed of a circular nanogrid sample support formed by interlocking two molybdenum bodies, thereby simultaneously securing structural strength and conductivity of the sample support. Since molybdenum is a high-strength metal and possesses conductivity that prevents charge during electron microscope analysis, it ensures stable fixation of the sample in a TEM or SEM analysis environment and increases the reliability of the analysis results.

[0017] In addition, the present invention can be usefully applied in various fields such as semiconductor device analysis, biological micro-sample processing, and nanomaterial structure analysis, and can significantly contribute to further advancing sample mounting technology for precision analysis equipment. Brief explanation of the drawing

[0018] FIG. 1 is a representative drawing of a circular molybdenum nanogrid sample support with an upper and lower double silicon post structure according to the present invention (the left side of the drawing is the upper and lower double structure support), and the right side of the drawing shows that a D-cut shape is also possible at the top of the silicon post of the lower structure among the double structures. Figure 2 shows the top of a silicon post of a nanogrid sample support having a uniform D-cut shape size and a D-cut shape penetrating the top of the silicon post. Figure 3 shows the top of a silicon post of a nanogrid sample support having a D-cut shape penetrating the top of the silicon post and having different D-cut shape sizes for each silicon post. Figure 4 shows the top of a silicon post of a nanogrid sample support having a uniform size without a D-cut shape penetrating the top of the silicon post. Figure 5 shows the top of the silicon post of a nanogrid sample support having different D-cut shape sizes for each silicon post and without a D-cut shape penetrating the top of the silicon post. Figure 6 shows the top of a silicon post of a nanogrid sample support having one long silicon post at the top of the silicon post and a D-cut shape penetrating the top of the silicon post. Figure 7 shows the top of a silicon post of a nanogrid sample support having one long silicon post at the top of the silicon post and a shape with various sizes of D-cut shapes penetrating the top of the silicon post. Figure 8 shows the top of a silicon post of a nanogrid sample support, in which the top of the silicon post is implemented in two stages, with the first stage having a stepped silicon post shape and the second stage having a uniform D-cut shape. Figure 9 shows the top of a silicon post of a nanogrid sample support, in which the top of the silicon post is implemented in two stages, the first stage having a non-D-cut silicon post shape, and the second stage having various D-cut shapes. Figure 10 shows the top of a silicon post of a nanogrid sample support having a shape in which the top of the silicon post has one long silicon post and the entire D-cut is penetrated through the top of the silicon post. Figure 11 shows the top of a silicon post of a nanogrid sample support having a shape in which the top of the silicon post has one long silicon post and the entire D-cut shape is not penetrated at the top of the silicon post. FIG. 12 shows the top of a silicon post of a nanogrid sample support having a silicon post shape with one long silicon post, and the top of the silicon post is composed of two stages, the first stage having a silicon post used to attach an analysis sample, and the second stage having a D-cut shape used to mount a sample. FIG. 13 is a view of the top of a silicon post of a nanogrid sample support having a silicon post shape with one long silicon post and the top of the silicon post composed of two stages, the first stage having a silicon post used to attach an analysis sample and the second stage having a through-type D-cut shape used to seat the sample. Specific details for implementing the invention

[0019] Unless otherwise defined, all terms used in this specification (including technical and scientific terms) may be used in a meaning commonly understood by those skilled in the art to which the present invention pertains. Additionally, terms defined in commonly used dictionaries are not to be interpreted ideally or excessively unless explicitly and specifically defined otherwise.

[0020] Hereinafter, specific details for implementing the present invention will be described in detail, focusing on the components of the claims.

[0021] The present invention is centered around a circular nanogrid sample support in which two molybdenum bodies are machined and joined to be precisely interlocked. Each molybdenum body may be insulated after precision electropolishing, or, if necessary, coated with a conductive plating (e.g., Pt, Au). These two bodies are formed in a semicircular or semi-dish structure and function as a complete circular nanogrid support when combined and viewed from the outside. Such a structure simultaneously provides sample fixation stability and anti-charge properties during TEM or SEM analysis.

[0022] One or more silicon posts are disposed at the top and bottom, respectively, within the circular nanogrid support. The silicon posts are manufactured using n-type or p-type high-resistance silicon wafers (thickness approximately 100 μm) and are formed into a stepped or multi-stage structure by repeating lithography and anisotropic dry etching processes. For example, a single silicon post has a stepped shape that narrows from bottom to top, with the uppermost step serving as a surface for fixing the sample. The thickness of this uppermost step is processed to approximately 5 μm to 10 μm, and the width is formed to approximately 20 μm to 50 μm. This structure minimizes background material outside the area where the sample is located, thereby eliminating background noise during TEM analysis, while simultaneously providing mechanically stable support for the sample.

[0023] The above silicon posts can be fabricated by selecting a stepped shape, a cylindrical shape, or a rectangular prism shape depending on the purpose of analysis. For example, the cylindrical shape is suitable for fixing spherical samples or bio-tissue samples, and the rectangular prism shape is suitable for fixing semiconductor cross-sectional thin sections. Multiple posts can be arranged symmetrically or asymmetrically on the upper and lower sides, respectively, with the spacing between posts set to approximately 100 µm to 300 µm. The above arrangement can be implemented in dozens to hundreds on a single silicon wafer using a high-precision photomask, enabling the simultaneous mounting of various samples on the same nanogrid sample support.

[0024] The sample is attached to the top of the silicon post, and the attachment method utilized is FIB-CVD (Ga or W deposition), conductive adhesive (Ag paste or carbon epoxy), or electrostatic attachment after a conductive coating. These methods are selected based on the analytical purpose and sample characteristics, and the sample is typically a thin section, biosection, or microstructure lifted out by FIB.

[0025] When mounted on an analysis instrument (TEM or SEM), the nanogrid support of the present invention can simultaneously analyze two samples attached to upper and lower silicon posts with a single loading. This allows for independent FIB processing, TEM observation, EDS analysis, etc., to be performed on each sample, and offers the advantage of enabling comparative analysis without the need for separate sample replacement. Since this structure eliminates the need to open the high-vacuum chamber multiple times, it can simultaneously reduce analysis time and sample damage.

[0026] Additionally, when performing Focused Ion Beam (FIB) processing after fixing the sample, the position and height of the silicon post are adjusted to allow downward processing even at an ion beam irradiation angle of 10 degrees or less, taking into account the sample fixation angle. For example, the height from the base of the silicon post to the top is approximately 20 μm to 30 μm, and the relative position with respect to the upper surface of the support is optimized through 3D simulation to ensure the irradiation angle. This is particularly useful in finishing processing steps, such as removing Ga ions using an Ar ion beam, and enables securing a clean processing surface without reattaching the sample.

[0027] The nanogrid sample support of the present invention is formed without a mesh structure overall and prevents external vibration or sample displacement during analysis based on the rigidity of the molybdenum body. The diameter of the entire support is 3 mm or less and the thickness is 100 µm or less, so it is accurately mounted on a TEM holder or SEM sample stage and can be reused repeatedly.

[0028] Such a structure and process can be applied to various precision analysis environments, such as semiconductor cross-sectional analysis, material thin section analysis, thin film interface analysis, and high-magnification observation of biological samples. In particular, it can significantly improve analysis efficiency, reproducibility, and productivity in environments requiring repeated experiments or in industrial settings where multiple samples must be processed within a limited analysis time.

[0029] A plurality of silicon posts may be arranged vertically on a circular molybdenum nanogrid sample support having an upper and lower dual silicon post structure according to the present invention. Each of these silicon posts serves as a structure for fixing a sample, and is preferably designed with a width of approximately 100 nm to 10 µm and a height of 1 µm to 50 µm. If the width is smaller than 100 nm, durability is poor, making it difficult to implement precisely in practice, and if the width is larger than 10 µm, it exceeds the width range required for precise semiconductor measurement. Additionally, the reason the height is 1 µm to 50 µm is that it is an optimized value to maintain mechanical stability while minimizing electron diffusion and interference effects that may occur during electron microscope analysis.

[0030] The top of the silicon post functions as a sample fixing part and is the surface where the sample actually contacts and is mounted. In the present invention, this top is designed to be formed in a flat shape or a D-cut shape. The D-cut shape consists of a cross-section formed by vertically cutting one side of the post and is highly advantageous when fixing the sample in a specific direction is required or when stably fixing asymmetric samples. The flat shape is suitable for samples of general shapes and is easy to mount and process. Each silicon post is processed to selectively have one of these shapes, which can be realized through lithography mask design and selective etching.

[0031] Silicon posts are arranged coplanarly on a nanogrid and are structurally separated to allow various samples to be individually mounted on the tops of different posts. This minimizes interference between samples and offers the advantage of enabling the comparison or parallel analysis of multiple samples in the same environment.

[0032] In addition, the shape of each post is selectively configured according to the size, shape, and purpose of analysis of the sample. For example, by selecting a wide flat post for relatively large-area or flat samples, and a D-cut post for irregular or sharp-edged samples, fixation stability can be ensured and analysis accuracy can be increased.

[0033] These post and nanogrid structures can be formed using MEMS (Micro Electro Mechanical Systems)-based processes that apply semiconductor process technology, rather than traditional mechanical machining methods. This process enables precision machining on the scale of tens of nanometers and allows for the repetitive, high-precision formation of hundreds to thousands of posts on the same substrate, making it highly advantageous for mass production and standardized analytical sample preparation.

[0034] The nanogrid sample support according to the present invention is compatible with various analytical instruments such as TEM (Transmission Electron Microscopy), SEM (Scanning Electron Microscopy), and FIB (Focused Ion Beam), and can be directly introduced into the analysis process with a sample mounted thereon. In particular, it is structured to allow for direct D-cut processing after the sample is fixed in the FIB instrument, making it suitable for subsequent analysis or reprocessing.

[0035] As such, each component of the present invention is organically combined to provide a sample support environment optimized for the characteristics and conditions of various analytical samples. The nanogrid structure ensures repeatability and reliability for high-resolution analysis by precisely arranging multiple posts, and the top shape of the posts is customized according to sample characteristics to minimize sample detachment or displacement. Furthermore, fabrication using MEMS-based processes enables mass production of high-quality products, enhancing applicability not only in laboratory settings but also in industrial settings.

[0037] The advantages and features of the nanogrid sample support of the present invention as described above, and the methods for achieving them, will become clearer by referring to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below but can be implemented in various different forms. The specific embodiments of the present invention are provided merely as examples to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims.

[0038] In one embodiment of the present invention, a D-cut shape as well as a planar shape is mixed at the top of a plurality of silicon posts, and multifunctional sample support is made possible through a structure in which these shapes are distributed in various ways within the same structure.

[0039] Figure 1 shows that in the circular molybdenum nanogrid sample support with an upper and lower double silicon post structure according to the present invention, the uppermost part of the double silicon post can also have a D-cut shape.

[0040] The uppermost part of the silicon post of the nanogrease sample support according to the present invention can be implemented in various shapes, and various embodiments of such uppermost part are as shown in the drawings.

[0041] As shown in FIG. 2, the through-hole D-cut shape at the top is suitable for cases where it is required for the electron beam to pass under the sample, and an array structure having a D-cut shape of the same size at each post can be implemented. Such a uniform structure is suitable for standardized sample analysis.

[0042] On the other hand, as shown in FIG. 3, a structure is also presented in which each silicon post is formed to have a D-cut shape of a different size, which is a flexible structure capable of simultaneously fixing samples of various sizes and shapes or responding to special analysis conditions.

[0043] As shown in FIG. 4, it is also possible to realize a case where the D-cut shape is not perforated, and this structure is suitable for an analysis environment where mechanical stability is particularly required or where electron beam leakage to the bottom must be prevented. Alternatively, in addition to the embodiment of FIG. 4 in which the non-perforated D-cut shape is uniformly applied throughout the post, a modified example having different D-cut sizes for each post may also be provided, as shown in FIG. 5.

[0044] Meanwhile, as shown in FIG. 6, a structure including only one central silicon post instead of a post array can also be implemented, in which case a through-hole D-cut shape is formed at the top of the post to enable precise center mounting and analysis of a single sample. Alternatively, as shown in FIG. 7, there is an embodiment in which a through-hole D-cut shape of various sizes is applied at the top of the post in the structure of FIG. 6, thereby providing various mounting options on a single post.

[0045] Furthermore, by implementing the uppermost part of the silicon post in a two-stage shape, various structural features for supporting and positioning the sample can be included. For example, as shown in FIG. 8, a stepped silicon post is formed at the lower end, and a uniform D-cut shape is provided at the upper end to simultaneously induce sample fixation and alignment. Alternatively, as shown in FIG. 9, it is also possible to configure the structure so that the sample can be selectively seated depending on the type of sample by forming a non-D-cut shape at the lower end and applying D-cut shapes of various sizes at the upper end.

[0046] In addition, as shown in FIG. 10, an embodiment in which a D-cut shape is penetrated across the top front surface of a single post structure, and as shown in FIG. 11, an embodiment in which a D-cut shape is not penetrated in the same structure can also be implemented, and this can be selectively applied depending on whether a path for the electron beam is secured.

[0047] In the case where the two-stage structure is designed more precisely, as shown in FIG. 12, a silicone post capable of directly attaching an analysis sample is formed in the first stage, and a D-cut shape for seating the sample is provided in the second stage, thereby simultaneously satisfying fixation and positional alignment. In addition, as shown in FIG. 13, if the D-cut shape of the second stage is formed as a through-hole structure, beam transmittance can be improved while sample support stability can be secured.

[0048] As such, the circular molybdenum nanogrid sample support with an upper and lower dual silicon post structure according to the present invention has an upper and lower dual silicon post structure and can be usefully utilized in various application fields such as high-resolution semiconductor analysis, material characterization, and structural analysis of biological samples. In particular, since multiple shapes are integrated within the dual support, analytical flexibility is greatly improved, and experimental repeatability and accuracy can also be improved.

Claims

Claim 1 A nanogrid sample support having an upper and lower dual silicon post structure, characterized in that two circular molybdenum (Mo) bodies are interlocked and joined to form a circular nanogrid sample support, and one or more silicon posts are installed in the upper and lower portions respectively within the circular nanogrid sample support, wherein the silicon posts have a stepped shape that narrows from the lower portion to the upper portion, and the uppermost portion of the silicon posts is processed into a D-cut shape where a flat portion and a vertical cut surface meet to fix the sample, and the nanogrid support can simultaneously analyze multiple samples by utilizing the upper and lower silicon posts respectively in a single loading process. Claim 2 A nanogrid sample support having an upper and lower double silicon post structure, characterized in that, in claim 1, each of the molybdenum bodies is made of a high-strength metal having high density and has conductivity to prevent charge during electron microscope analysis. Claim 3 A nanogrid support having an upper and lower double silicon post structure, characterized in that, in claim 1 or claim 2, the molybdenum body is formed into a small structure with a diameter of 3 mm or less and a thickness of 100 μm or less, making it easy to handle. Claim 4 A nanogrid sample support having an upper and lower dual silicon post structure, characterized in that, in claim 1 or claim 2, the D-cut shape may be penetrated downward or not penetrated, and a plurality of silicon posts may be uniform or non-uniform, and the D-cut shape silicon posts for various semiconductor analyses are included. Claim 5 A nanogrid sample support having an upper and lower double silicon post structure, characterized in that, in claim 1 or claim 2, the width of the silicon post is in the range of 100 nm to 10 µm and the height is in the range of 1 µm to 50 µm. Claim 6 A nanogrid sample support having an upper and lower dual silicon post structure, characterized in that, in claim 1 or claim 2, the silicon post is a MEMS structure formed by semiconductor process technology. Claim 7 A nanogrid sample support having an upper and lower double silicon post structure, characterized in that, in claim 1 or claim 2, the silicon posts are arranged on the same plane and designed so that samples of various shapes can be mounted on the top of individual posts. Claim 8 A nanogrid sample support having an upper and lower dual silicon post structure, characterized in that the nanogrid sample support according to claim 1 or claim 2 is utilized in a TEM, FIB, or SEM analysis process after sample mounting. Claim 9 A nanogrid sample support having an upper and lower double silicon post structure, characterized in that, in claim 1 or claim 2, the uppermost portion of the silicon post is formed through cutting (FIB D-cut).

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