Reaction apparatus and method for atomic layer deposition and Fresnel zone plate production.

Abstract

The present invention relates to a reaction apparatus and method for depositing one or more atomic layers of at least one material onto a substrate. The reaction apparatus comprises a showerhead, a base stage, and a reaction chamber housing at least one substrate holder. The showerhead comprises at least one gas outlet configured to supply a gas stream of at least one material or at least one component of at least one material. The base stage is rotatable about a base stage rotation axis. At least one substrate holder is positioned on the base stage and configured to rotate a substrate about a substrate rotation axis. In particular, the substrate holder is configured to rotate a substrate about a substrate rotation axis in such a manner that the base stage rotation axis and the substrate rotation axis are inclined relative to each other. The present invention also relates to an X-ray microscope that produces magnified images of objects using X-rays.

Description

[Technical Field]

[0001] The present invention relates to a reaction apparatus and method for depositing one or more atomic layers made of at least one material onto a substrate. Furthermore, the present invention relates to a Fresnel zone plate and an X-ray microscope, comprising a Fresnel zone plate for generating a magnified image of an object using X-rays. [Background technology]

[0002] In the photon energy range of X-rays, the complex refractive index n=1-δ-iβ approaches 1 for all materials, so it is generally known that focusing X-rays at relatively short focal lengths is difficult. Here, δ and β represent the dispersion and absorption of the material.

[0003] One method for focusing X-rays with relatively short focal lengths is to use diffractive optical elements such as Fresnel zone plates (FZPs). An FZP is a concentric diffraction grating consisting of a set of alternately concentric rings, also called Fresnel zones or simply zones, made from two different materials having different mass absorption coefficients and / or different phase shifts for the photon energy used. For high X-ray energies above 8 keV, the phase shift of the X-rays due to the selection of the two materials is the primary factor in achieving high diffraction efficiency. Here, a differential phase shift of nearly 180° between two adjacent zones is desired. X-rays transmitted through the FZP are diffracted. The zone period, which varies across the entire FZP, is selected so that all primary X-rays diffracted from the incident parallel X-ray beam are focused at the focal point. In commonly used primary diffraction, the FZP acts as a thin lens that can form an image of the object. In this full-field imaging mode, the sample object is placed between the X-ray source and the FZP. Alternatively, the FZP can be used as a focusing optical element with the sample object placed at the focal point of the FZP, which is located behind the X-ray source and in front of the sample object. Scanning the sample object also forms an image with a resolution determined by the focal spot diameter of the FZP. This mode is called scanning transmission X-ray microscopy (STXM). The radius of each Fresnel zone follows the zone plate law described in the paper "Simulation of High-Resolution X-ray Zone Plates" by Alexei N. Kurokhtin and Alexei V. Popov (J. Opt. Soc. Am. A, Vol. 19, pp. 315-324, 2002). The resolution of the FZP lens is mainly limited by and approximately equal to the width of the outermost zone (e.g., Y. Vladimirsky, DP Kern, THP Chang, DT Attwood, N. Iskander, S. Rothman, K. McQuaide, J. Kirz, H. Ade, I. McNulty, H. Rarback, and D. Shu, paper "Zone plate lenses for X-ray microscopy", Nuclear Instruments and Methods in Physics Research Section A: Accelerators, (See Spectrometers, Detectors and Associated Equipment, Vol. 266, Nos. 1-3, 1988, pp. 324-328, ISSN 0168-9002). For example, to achieve an X-ray imaging resolution of 50 nm using a primary opening-order focus, the width of the outermost zone must be less than 50 nm. To obtain reasonable efficiency for the FZP, the height of the FZP, related to the zone height, must be optimized for each photon energy. In particular, at high photon energies above 8 keV, depending on the materials used, an FZP with a very high aspect ratio (height-to-width ratio), typically exceeding 100, is required to achieve a phase shift close to 180°. For example, in a two-layer system using aluminum oxide (Al2O3) and zinc oxide (ZnO), an FZP height, i.e., zone height of 36.33 μm is required to achieve an operating phase shift of 180° at 17.5 keV. If the width of the outermost zone is 50 nm, this corresponds to an aspect ratio of approximately 720.

[0004] Various methods have been attempted to achieve a high aspect ratio in the outermost zone of FZPs. For example, planar patterning processes, including electron beam lithography for nanoscale patterning and deep reactive ion etching for pattern transfer, known in the semiconductor industry, can be used to manufacture FZPs with an aspect ratio of 30-40 in the outermost zone. However, with such aspect ratios, the resulting FZPs cannot be used as X-ray lenses for photon energies above 8 keV in high-resolution applications requiring very high aspect ratios. Therefore, finding a new manufacturing method to obtain FZPs with a high aspect ratio in the outermost zone that are suitable for focusing X-rays above 8 keV is an urgent task.

[0005] Furthermore, a manufacturing process for FZP based on a bottom-up layer deposition process, rather than a top-down (planar) patterning process, has also been proposed. The bottom-up layer deposition process can be realized by atomic layer deposition (ALD). ALD is a technology that can conformally coat any substrate with atomic-level precision. For example, WO2011 / 054651A1 describes a manufacturing process for FZP using ALD. In this process, a substrate that is rotationally symmetric with respect to the central axis is prepared, and without rotating the substrate, layers are sequentially deposited on the substrate region by the ALD process to form a coated substrate, and at least one disk is separated from the coated substrate by splitting the coated substrate at least once perpendicular to the central axis. This conventional ALD process has the first limitation that the deposition rate is very slow. For example, depositing an FZP layer with a width of 10 μm requires a deposition time of more than 12 days, and manufacturing an FZP with a width of 300 μm, which is a more reasonable size for practical X-ray imaging systems, can take more than a year. Transitioning to a high-speed ALD cycle is problematic because it shortens the residence time of the precursor, which can lead to variations in thickness, especially on the side opposite the showerhead. [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The present invention aims to provide an improved reactor and an improved method for depositing one or more atomic layers of at least one material onto a substrate, enabling the routine production of FZPs (Fiber-Zoned Plasma) that are practical for imaging applications at high photon energies exceeding 8 keV. Furthermore, the present invention aims to provide an improved FZP for focusing X-rays above 8 keV, and an improved X-ray microscope for generating magnified images of objects using X-rays. [Means for solving the problem]

[0007] The present invention proposes a reaction apparatus for depositing one or more atomic layers of at least one material onto a substrate. The reaction apparatus comprises a showerhead, a base stage, and a reaction chamber housing at least one substrate holder. The showerhead has at least one gas outlet configured to supply a gas stream consisting of at least one precursor or reaction gas, or at least one component of at least one material. Preferably, the gas stream may be supplied continuously or in pulses by the showerhead. The base stage is rotatable around a base stage rotation axis. Preferably, during operation of the reaction apparatus, the base stage may rotate continuously, or it may be moved in a manner that involves repeated stopping and starting. At least one substrate holder for holding a substrate for zone deposition is positioned on the base stage and configured to rotate the substrate around a substrate rotation axis. In particular, the substrate holder is configured to rotate the substrate around the substrate rotation axis in such a manner that the base stage rotation axis and the substrate rotation axis are inclined with respect to each other, preferably substantially perpendicular to each other.

[0008] This invention includes the recognition that ALD operates within a so-called ALD temperature window, where the growth rate does not depend on the amount of precursor introduced, i.e., above a saturation threshold. Since the precursor is introduced into the reaction chamber by pulse, a certain pulse duration is generally required to reach saturation. Thus, growth is self-regulating, and the overall layer thickness corresponding to the subsequent FZP zone width usually depends only on the number of ALD cycles. Conventionally, each ALD cycle consists of four subcycles: precursor A pulse, purge gas pulse, precursor B pulse, and purge gas pulse. The purge gas can also be mixed with the precursor. The purge gas pulse can also be performed as a continuous gas flow throughout the cycle. Therefore, the growth rate of conventional ALD (i.e., without rotation) is typically limited to about 1 angstrom per cycle. As a result of this low growth rate, long deposition times are required to obtain the layering necessary for practical FZPs where a deposition thickness of several tens of micrometers is required. If the realistic total cycle time is 10 seconds, a 10 μm layering requires approximately 12 days of deposition time. Spatial ALD can achieve growth rates of approximately 1 nm (or more) per minute on planar substrates. In spatial ALD, the substrate rotates in circular motion under individual continuous gas flows, rather than pulsed ones. The pulse duration is determined by the rotation frequency. Conventional ALD growth rates, along with rotation frequency, are expressed as growth per cycle (GPC), which can be rewritten as growth per minute (nm). Considering that one rotation of the substrate under four individual gas flows (each gas flow corresponding to one of the conventional ALD subcycles) constitutes one complete ALD cycle, a rotation frequency of 0.16 Hz, for example, 10 rotations per 60 seconds, is required to achieve a growth rate of 1 nm / min at a growth rate of 1 angstrom per cycle. Higher growth rates, i.e., higher rotation frequencies, typically result in shorter residence times under each precursor or reactive gas flow, as well as under the purge gas flow. As a result, the pulse time may fall below the saturation threshold, i.e., the minimum pulse time / residence time, and therefore outside the self-controlled growth region. Even slight changes in pulse time / residence time due to changes in rotation frequency generally alter the growth rate.This can reduce the uniformity of the deposition process on rotationally symmetric substrates such as glass fibers or metal wires, which is necessary to achieve a high aspect ratio in the outermost zone.

[0009] The reaction apparatus according to the present invention can produce FZPs for focusing X-rays with energies of 8 keV or higher, that is, FZPs with an aspect ratio of the outermost layer exceeding 100. In particular, this reaction apparatus can produce FZPs by depositing regions of a predetermined width on a rotationally symmetric substrate. For example, layers of a first material and a second material with different physical absorption and / or refractive properties can be alternately deposited on a circular substrate or core. FZPs for focusing high-photon-energy X-rays produced using this reaction apparatus can have a high aspect ratio, for example, the FZP can have a width of several μm, and can be composed of a thin Fresnel zone with an outer layer zone width of 50 nm or less. In particular, the ALD reaction apparatus according to the present invention is an effective technology for achieving a target resolution of 10 nm at X-ray energies of 8 keV or higher.

[0010] This is possible because the reaction chamber is configured to provide a first rotation that preferably continuously rotates the base stage around the base stage rotation axis, and a second rotation that further rotates the substrate holder around the substrate rotation axis. Thus, within the reaction chamber, the substrate held by the substrate holder is rotated directly by the substrate holder around the substrate rotation axis, and indirectly by the base stage around the base stage rotation axis. The advantage of combining a rotatable base stage and a rotatable substrate holder is that, in addition to a relatively high deposition rate, uniform deposition is possible on the substrate layer by three-dimensional cycle control (a cycle being the residence time by controlling the rotation frequency of the substrate under each continuous gas flow), which allows for a relatively high layer thickness corresponding to the zone width, precision, and low interface roughness of the final product, as well as low surface roughness during the manufacturing process. Furthermore, in order to obtain the desired resolution, the FZP substrate has a desired outermost zone width wN With respect to the minimum roundness, ba = c ≤ (1 / 2)w N (See Figure 2. 201 corresponds to a, 202 to b, and 203 to c), and the substrate roughness is also required to be within the same range. Here, if the interface roughness of the final product, for example, the outermost zone width of the FZP, is 50 nm or less, it is possible to achieve a root mean square (RMS) of 0.5 nm and a zone width accuracy Δw(RMS) / w < 0.01.

[0011] Preferably, the substrate holder is configured to hold a substrate such as glass fiber or metal wire. Preferably, the substrate holder is positioned and configured to hold the substrate perpendicular to the direction of flow of the gas flow supplied from or introduced through the gas outlet.

[0012] Preferably, at least one substrate holder includes a substrate holder drive mechanism comprising a motor and a substrate mounting support connected to the motor, which holds the substrate and rotates the substrate around a substrate rotation axis. Thus, the substrate rotation axis is defined as a characteristic of the substrate holder and refers to a rotation axis around which the substrate held by the substrate holder can be rotated by the substrate holder.

[0013] Preferably, the base stage and the substrate holder are rotatable independently around their respective axes of rotation. For this purpose, a base stage drive mechanism and / or a substrate holder drive mechanism may be provided as appropriate. The base stage drive mechanism and / or the substrate holder drive mechanism may include, for example, a servo motor. Alternatively, the base stage drive mechanism and / or the substrate holder drive mechanism may include a printed circuit board (PCB) motor or a brushless (BL) motor. Preferably, the substrate holder drive mechanism is mounted in a frictionless manner to minimize the generation of dust and particles. Furthermore, a control unit may be provided to control the base stage drive mechanism and / or the substrate holder drive mechanism, i.e., to specify their respective rotational speeds. Thus, the base stage drive mechanism and / or the substrate holder drive mechanism can be controlled independently of each other. The two drive mechanisms are not coupled; however, they can be coupled.

[0014] When there are two or more substrate holders on the base stage, it is possible to individually control each substrate holder using one or more control units. For example, by providing a number of contact feed-throughs corresponding to the main rotary feed-through, the individual motors of the substrate holders can be controlled, which can be realized when, for example, a sufficient number of motor control units are present. Alternatively, a control unit for controlling the substrate motors can be configured such that the substrate motors rotate at the same frequency during the operation of the reaction apparatus, for example, all the substrate motors are operated via the same control unit. Instead of this, a rigid mechanical connection to the base stage rotation axis is also possible. The operative connection between the base stage drive mechanism and the substrate holder drive mechanism can be realized via a gear system, preferably a planetary gear system. The gear ratio can be set such that a 360° movement of the substrate around the substrate rotation axis can be realized. That is, for one rotation around the base stage rotation axis driven by the base stage drive mechanism, in order to ensure uniformity, it may be set to at least 4 times one rotation, more preferably 8 rotations or 16 rotations. In this case, the base stage drive mechanism (for example, one main motor) rotates the substrate via an appropriate transmission ratio. To change the frequency, usually, the gears of the substrate holder may be replaced.

[0015] In addition to or instead of this, the base stage comprises a base stage drive mechanism configured to rotate the base stage around the base stage rotation axis. Preferably, at least one substrate holder comprises a substrate holder drive mechanism configured to rotate the substrate around the substrate rotation axis. Further preferably, the base stage drive mechanism and the substrate holder drive mechanism are operatively connected such that the rotation provided by the base stage drive mechanism can be transmitted to the substrate holder drive mechanism to rotate the substrate.

[0016] At least one substrate holder can be detachably attached to the base stage. For example, the substrate holder has a plate-like form configured to hold a substrate and can be pressed against the base stage and snapped into place. Mechanical couplings to enable rotation of the substrate can be provided, for example, via a mechanical rotation coupling, or preferably via electrical contact with a rotary motor on the substrate holder.

[0017] Particularly preferred is that the substrate holder is positioned and configured to rotate the substrate by a substrate rotation axis that is substantially perpendicular to the base stage rotation axis. Such a reactor includes further rotation of the substrate via one or more substrate holders by a substrate rotation axis perpendicular to the gas flow and along the central axis of the substrate. That is, during the operation of the reactor, the substrate held in the substrate holder is rotated by a base stage rotation axis perpendicular to the rotationally symmetric substrate, such as glass fiber or metal wire, and parallel to the gas flow, and further rotates around a substrate rotation axis parallel to the longitudinal axis of the substrate. The substrate is mounted in a substrate holder that allows for additional rotation around the substrate rotation axis and is simultaneously positioned on a main base stage that is rotatable around the base stage rotation axis. Therefore, in addition to or instead of this, it is even more preferable that the substrate holder is positioned and configured to rotate the substrate such that the substrate rotation axis is substantially perpendicular to the gas flow direction from which the gas flow is supplied, and is predetermined by at least one gas outlet. Furthermore, in addition to or instead of the above, the base stage is preferably predetermined by at least one gas outlet and is rotatably positioned and configured such that its axis of rotation is parallel to the gas flow direction from which the gas flow is supplied. Preferably, the gas outlet is configured to introduce the gas flow into the reaction chamber along the gas flow direction.

[0018] Preferably, the reaction chamber comprises a base stage heating element capable of heating the base stage. In addition to or instead of this, the reaction chamber may comprise a radiation source that supplies infrared rays. The radiation source may be configured and arranged to supply an infrared heating spot so that a substrate held by the substrate holder can be heated in a spatially localized area. Therefore, in the reaction chamber, direct heating of the substrate by the base stage heating element and / or indirect heating by the radiation source can be provided. The radiation source can be arranged outside the reaction chamber. In that case, the reaction chamber may comprise a window that transmits infrared rays provided by the radiation source. Alternatively, the radiation source can be arranged inside the reaction chamber. In this case, unlike the case where a window is provided in the reaction chamber wall, there is an advantage that the gas flow is less likely to be affected by the opening or flange of the transmission window. The heater assembly inside the reaction chamber can be rationalized.

[0019] Preferably, the reaction chamber comprises a substrate holder heating element arranged and adapted to heat at least one substrate holder. In addition to or instead of this, each removable substrate holder has its own heating element. The advantage of providing a substrate holder heating element is, for example, that in other places, deposition at an appropriate temperature outside the ALD temperature window can be minimized. Furthermore, this can avoid (or reduce) the unintentional accumulation of flakes caused by the peeling of the coating on the walls and other components in the reaction chamber onto the substrate.

[0020] Preferably, the reaction chamber comprises a plurality of substrate holders arranged on the base stage, and each of the plurality of substrate holders is rotatable independently about its own substrate rotation axis with respect to the base stage. The plurality of substrate holders are preferably arranged circularly along the base stage.

[0021] Preferably, the showerhead is divided into four sections, the first section having a first gas outlet for supplying a first gas stream containing a first precursor gas or reaction gas to be deposited and / or at least one component of the material to be deposited; the second section having a second gas outlet for introducing a first purge gas; the third section having a third gas outlet for supplying a second gas stream containing a second precursor gas or reaction gas to be deposited and / or at least one component of the material to be deposited; and the fourth section having a fourth gas outlet for introducing a second purge gas. The first and second purge gases may have the same composition. The purge gas may be a non-reactive gas, such as an inert gas like argon. A small vacuum (or purge gas / curtain gas) section may be provided between the individual sections. This can prevent gas mixing. If necessary, this vacuum section can also supply purge gas instead of vacuum, and is switchable between vacuum and purge gas. Preferably, the first and third sections, and the second and fourth sections, are arranged to face each other, with one of the second and fourth sections positioned between the first and third sections in both directions. It is desirable that the gas flow in each section be introduced continuously. In addition to or instead of this, each gas may be introduced sequentially or in a pulsed manner, with the first and second gases serving as purge gases for the purge step, respectively. It is desirable that the period and pulse time of the introduced gases be synchronized with the rotation frequency of the base stage.

[0022] The first and third gas streams may each contain a carrier gas. The carrier gas preferably contains a precursor or reaction gas containing the material to be deposited or its respective components. The reaction apparatus preferably includes a control unit that controls at least one deposition parameter based on sensor signals provided by the sensor. Examples of measuring sensors include quartz microbalances, reflectance measuring sensors, reflectance anisotropy spectroscopy (RAS) sensors, or single-wavelength or spectroscopic ellipsometry sensors. Thus, adaptive control of the deposition parameter based on sensor input is possible, for example.

[0023] The showerhead section can be further subdivided into circular / arc-shaped segments that can be individually stopped, switched to purge gas, or switched to vacuum. Segment subdivision is preferably performed above the substrate, for example, in the substrate holder area. For substrates such as fibers with a length of 1 cm, subdivisions with a radius of r ≤ x ≤ r + 1 cm are sufficient, and the substrate fibers can be placed below the r ≤ x ≤ r + 1 cm segments. Segments smaller than r, and the remaining segments larger than r + 1 cm, can similarly be treated as relatively large subsegments for purging and deposition at the substrate edges. This also applies to substrates longer or shorter than 1 cm. The upper limit of the substrate length may be given as half the diameter of the base stage. For patterning purposes, the radial diameter of the subsegments may be as small as possible and uniform across all segments, but can also be variable for fixed deposition processes and FZP products, for example. The upper diameter should be approximately 20 μm, for example, a typical inkjet nozzle size at 1200 dpi, but preferably less than 1 μm. For a substrate with a length of 1 cm and a subsegment size of 1 μm, approximately 10,000 segments would be advantageous. Preferably, the reactor is configured to allow segments not used for introducing the gas flow during operation to be switched to a purge gas or vacuum. This is advantageous for achieving the desired patterning effect.

[0024] Preferably, the reaction apparatus includes a distance adjustment unit configured to adjust the distance between the base stage and the showerhead. The distance between the base stage and the showerhead can be adjusted using the distance adjustment unit during the deposition of one or more atomic layers of at least one material for forming a layer on the substrate. For example, the distance adjustment unit is controlled by a control unit, and the minimum distance is set by the showerhead making direct contact with the substrate holder, and the maximum distance is set by the showerhead retracting completely into the upper half of the reaction chamber. Preferably, this maximum distance is greater than or equal to the diameter of the base stage. In addition to or instead of this, the base stage and the substrate holder can be moved up and down.

[0025] The present invention also relates to a method for depositing one or more atomic layers of at least one material onto a substrate using the reaction apparatus described herein. This delicious, - The steps of placing a circuit board on at least one circuit board holder, - A step of placing a substrate holder on the base stage of the reaction chamber, - A step of introducing a gas stream containing at least one material and / or at least one component of at least one material into the reaction chamber through at least one gas outlet, - A step in which the substrate is rotated using the base stage around the base stage rotation axis, and further rotated using the substrate holder around the substrate rotation axis, with the base stage rotation axis and the substrate rotation axis being inclined relative to each other. - The process includes the step of depositing one or more atomic layers of at least one material and / or at least one component of at least one material onto a substrate. In this method, the substrate is preferably glass fiber or metal wire.

[0026] In this method, it is preferable to deposit alternating layers of the first and second materials on a substrate in the form of concentric rings with controlled widths. The first and second materials differ in at least one physical property. This physical property refers to absorption properties, dispersion properties, particularly dispersion properties for X-rays, residual stress of the layer materials, or thermal expansion of the materials used. The first and second materials may be, for example, oxides, nitrides, silicides, carbides, or metals. It is desirable that the first material has sufficient contrast with respect to the substrate and the second material for X-rays in a predetermined photon energy range. That is, the refractive index of the material is given by n = (1-δ) - i × β, where δ and β represent dispersion and absorption, respectively. To obtain sufficient contrast, for X-rays with an energy of 8 keV or higher, the difference between δ and β between the two materials should be Δδ > 1E -9 and Δβ>1E -10 It needs to be greater than [a certain value]. Therefore, the difference in complex refractive index between the first material and the second material must be large enough to achieve high focusing efficiency.

[0027] At least one material is desirable to have self-smoothing properties during deposition, preferably during Al2O3 deposition. A self-smoothing material refers to a material (or precursor in the ALD deposition process) whose surface roughness decreases during the deposition process, for example, the final surface roughness of the deposited material becomes lower than the surface roughness of the substrate or the material being deposited, for example, as described by Myers et al. in "Smoothing surface roughness using Al2O3 As described in "Atomic Layer Deposition (Smoothing of Surface Roughness by Al2O3 Atomic Layer Deposition)" (Applied Surface Science 569, 150878, 2021), the RMS roughness is reduced from 3.3 nm to 1.5 nm.

[0028] The two materials should ideally be interchangeable with respect to each other and with respect to the substrate. For example, they should exhibit good adhesion (bonding to the underlying material) and low residual stress that could cause cracking or delamination.

[0029] In this method, the width and number of zones are selected according to the Fresnel zone plate law (A. J. Fresnel, "Calcul de l’intensite de la lumiere au centre de l’ombre d’un ecran et d’une ouverture circulaires eclaires par un point radieux", Oeuvres Completes d’Augustin Fresnel, Imprimerie Imperiale, Paris, 1866) and controlled by adjusting the deposition parameters.

[0030] Preferably, in this method, at least one material is deposited at a deposition rate of 1 nm or more per minute, preferably 10 nm or more per minute. This corresponds to a rotation frequency of the base stage of 0.16 Hz or 1.6 Hz for a typical growth rate of 1 angstrom per cycle.

[0031] Preferably, this method includes cleaning the substrate before or after placing a substrate holder with the substrate on a base stage in a reaction chamber or a suitable pre-chamber (transfer chamber) using a CO2 snow gun, an ozone source / generator, a plasma source, for example, sputtering using a cluster source such as argon, nitrogen, hydrogen, oxygen, for example, argon, nitrogen, helium, or C60, or etching such as reactive ion etching using, for example, CF4 / Ar. Instead of this, or in addition to this, a gas flow from an ALD shower head can also be used for substrate cleaning. The cleaning step can be used to obtain a substrate free of foreign substances with a contamination (particle) density of less than 1×10 6 / cm 2 less, preferably less than 1×10 4 / cm 2 less. However, it is preferable that the cleaning procedure does not increase the surface roughness and does not increase the roundness of the substrate. For example, as shown in FIG. 2, for the zone width w N of the outermost zone, the minimum value b - a = c ≦ (1 / 2)w NIt is undesirable for the roundness to increase while the roughness is within the same range.

[0032] This method may include a step of performing a surface termination treatment or a surface functionalization treatment. In particular, the surface termination treatment or surface functionalization treatment in the ALD process may be achieved, for example, by using OH groups in particular for oxide deposition, C groups in particular for carbide deposition, and NH groups in particular for nitride deposition.

[0033] The present invention further relates to the use of the reaction apparatus described herein for the production of FZP. Preferably, the FZP manufactured using a reactor comprises a first material and a second material arranged concentrically and alternately on a substrate according to Fresnel's zone-plate law. The FZP preferably has an aspect ratio, defined as the ratio of the zone height to the width of the outermost zone, of 50 or more, and a zone width of 50 nm or less for the outermost zone. Preferably, the FZP has a surface roughness and / or interface roughness of 0.5 nm or less. Optionally, the FZP may have a zone width accuracy Δw(RMS) / w of 0.01 or less, preferably a zone width of at least 0.2 nm, and a roundness of each zone R≧1-((1 / 2)w N ) / b or more (where w N (where represents the width of the outermost zone), and / or the aspect ratio of the outermost zone may be 50 or more. Preferably, w N It is less than 50 nm.

[0034] Furthermore, the present invention relates to an X-ray microscope that generates a magnified image of an object using X-rays. This X-ray microscope comprises an X-ray source, a first X-ray optical element, a sample object stage, a second X-ray optical element, an X-ray imaging detector, and a control unit. A pinhole and aperture may also be used as needed. The X-ray detector is configured to detect X-rays supplied from the X-ray source and transmitted through the object. The first X-ray optical element is used to collimate the X-rays for irradiating the sample object and is automatically movable in and out of the X-ray beam path between the X-ray source and the sample object. The second X-ray optical element is an FZP that is automatically movable in and out of the X-ray beam path between the sample object and the X-ray detector. Preferably, the FZP used as the second X-ray optical element comprises a first material and a second material arranged alternately in a concentric ring shape on a substrate according to Fresnel's zone-plate law. Preferably, the FZP has an aspect ratio, defined as the ratio of the height of a zone to the width of the outermost zone, of 50 or more, and the zone width of the outermost zone is 50 nm or less. The FZP preferably has a surface roughness and / or interface roughness of 0.5 nm or less. Optionally, the FZP has a zone width accuracy Δw(RMS) / w of 0.01 or less, and the roundness of each zone is R≧1-((1 / 2)w N ) / b or more (here w N w indicates the width of the outermost zone, and / or the aspect ratio of the outermost zone may be 50 or more. Preferably, w N The wavelength is 50 nm or less. The FZP used as the second X-ray optical element is preferably manufactured using the reaction apparatus and method described herein.

[0035] The control unit is configured to control the automatic movement of the first X-ray optical element and the second X-ray optical element into and out of the beam path. Furthermore, the control unit is configured to align the first X-ray optical element and the second X-ray optical element with respect to the beam path, for example, using an interferometer or capacitive alignment system.

[0036] The X-ray microscope can operate in two different modes: micro-X-ray imaging mode and nano-X-ray imaging mode. In micro-X-ray imaging mode, images of objects can be recorded with micrometer resolution. For this purpose, the control unit is configured to move the first X-ray optical element and the second X-ray optical element out of the beam path. In nano-X-ray imaging mode, images of objects can be generated with nanometer resolution. To record images of objects with nanometer resolution, the control unit is configured to move the first X-ray optical element and the second X-ray optical element into the beam path. The combination of micro-X-ray imaging mode and nano-X-ray imaging mode is made possible by FZP for high-energy X-rays with sufficient penetration power to enable micro-X-ray imaging. Preferably, nanometer resolution refers to a resolution of 100 nm or less. Preferably, micrometer resolution refers to a resolution of 5 μm or less, for example, a resolution greater than 100 nm and less than or equal to 5 μm.

[0037] Nano-XCT typically has a resolution of 100 nm or less (limited, for example, by the outermost zone width of the FZP), while micro-XCT has a resolution of 5 μm or less (limited, for example, by the spot size of the X-ray source and the resolution of the X-ray detector).

[0038] In micro-X-ray imaging mode and nano-X-ray imaging mode, the X-ray microscope can record multiple 2D images of the sample object at different spatial orientations, for example, by rotating the sample object between images. From the recorded 2D image set, a 3D reconstruction of the sample object can be calculated, for example, using an image processing unit. Therefore, in micro-X-ray imaging mode, multiple images of an object can be recorded at micrometer resolution, and a 3D reconstruction with a micrometer voxel size can be calculated from the 2D image set. Similarly, in nano-X-ray imaging mode, multiple images of an object can be recorded at nanometer resolution, and a 3D reconstruction with a nanometer voxel size can be calculated from the 2D image set.

[0039] Preferably, the first X-ray optical element can be moved automatically and reproducibly into and out of the X-ray beam path between the X-ray source and the object. Preferably, the second X-ray optical element can be moved automatically and reproducibly into and out of the X-ray beam path between the object and the X-ray detector. In this specification, reproducibility means an accuracy of 1 μm or less for coarse linear alignment and 100 nm or less for fine linear alignment. The angular alignment accuracy must be 10 μrad or less, preferably 1 μrad. In particular, the control unit is configured to control the automatic and reproducible movement of the first X-ray optical element and the second X-ray optical element into and out of the beam path, respectively.

[0040] This invention includes a further recognition that known nanoscale X-ray microscopes with a resolution of approximately 50 nm have not been widely adopted in industrial applications due to limitations in their ability to penetrate objects and the considerable time required for sample preparation. The thickness of sample objects is limited to tens of micrometers or less, depending on the material and type of microscope. For example, sample objects for imaging with known X-ray microscopes operating at 8 keV need to have a thickness of approximately 100 μm, depending on their composition. In many cases, such as silicon or metallic samples, the sample thickness must be less than 100 μm. This means that photons of this energy cannot penetrate a 780 μm thick silicon wafer. In actual industrial products such as highly integrated microchips, chiplets, and packaged chips, cutting, polishing, and / or deprocessing techniques are required to achieve nanoscale imaging conditions. In the case of batteries, it may even be necessary to manufacture special miniature test cells that differ significantly from actual batteries to meet imaging requirements. This preparation process is often difficult and time-consuming.

[0041] Furthermore, existing systems are generally limited by the X-ray lenses they use and operate only at very low X-ray energies that do not have the ability to penetrate thick objects. However, with high-energy X-rays that can penetrate deep into objects, nanometer resolution cannot be achieved without the use of special optical elements.

[0042] The X-ray microscope according to the present invention overcomes these drawbacks, directly accepting relevant samples without complex preparation, and seamlessly realizing assisted navigation to the region of interest and nanoscale imaging, thereby providing a solution suitable for industrial deployment. Furthermore, this X-ray microscope can operate with monochromatic high-energy X-rays of 8 keV or higher, such as 17.5 keV molybdenum Kα, 20.2 keV rhodium Kα, or 24.2 keV indium Kα, and is equipped with a high-power X-ray source that can penetrate thick objects using regenerative targets such as solid anodes, microfocus anodes, rotating anodes, or metal band or liquid metal jet X-ray sources using conventional electron excitation or induced plasma excitation methods. Because the second X-ray optical element is the FZP according to the present invention, it is possible to generate nanoscale resolution images while maintaining penetration into objects, which represents a paradigm shift in X-ray microscopy technology. The X-ray microscope can acquire microscale two-dimensional images and move them over the sample object without using an X-ray optical system, and generate low-resolution three-dimensional schematic reconstruction images of the sample object.

[0043] Switching between micro-X-ray imaging mode and nano-X-ray imaging mode is seamless and transparent for the user, without the need to transfer the sample object to another device or perform navigation procedures. Two X-ray optical elements are inserted into the beam path to switch from projection-based (lensless) micro-X-ray imaging mode to nano-X-ray imaging mode. Except for initial alignment, no manual adjustments or alignments are required. For example, adjustments due to mechanical and thermal instabilities may be handled autonomously using software and hardware, such as pre-trained artificial neural networks for alignment assistance, or closed-loop sensor-based alignment systems, such as interferometer, capacitive, or image sensor alignment systems.

[0044] Preferably, the first X-ray optical element is configured to focus light from an X-ray source onto a small area of ​​the sample object to be imaged (focused illumination optical system). Alternatively, the photon energy spectrum from the X-ray source is filtered to direct as many X-ray beams as possible onto the characteristic emission lines of the X-ray source. The first X-ray optical element is preferably an elliptical single-reflection capillary or a focusing multilayer monochromator with a reflective surface coated with a suitable material. Preferably, the X-ray microscope includes a positioning system configured to guide transitions from micro-X-ray imaging mode to nano-X-ray imaging mode and vice versa. The positioning system may include a control unit. Preferably, the control unit includes an artificial neural network trained to align the first and second X-ray optical elements with respect to the beam path to generate an image of the object at nanometer resolution, using sensor data from the microscope as input.

[0045] It is understood that the embodiments described above, specifically the reaction apparatus of claim 1, the method of claim 9, and the X-ray microscope of claim 14, have similar and / or identical preferred embodiments, particularly as characterized in the dependent claims. It is understood that preferred embodiments of the present invention may be any combination of the dependent claims or the embodiments described above with each independent claim. These and other embodiments of the present invention will become apparent and be explained by referring to the embodiments described later. [Brief explanation of the drawing]

[0046] [Figure 1] These are plan and cross-sectional views illustrating a Fresnel zone plate in a schematic and illustrative manner. [Figure 2] These are schematic and illustrative plan and perspective views showing a round core substrate with low circularity. [Figure 3] This is a schematic and illustrative perspective view showing cylindrical core substrates and tapered core substrates. [Figure 4] This diagram schematically and illustratively shows, from different viewpoints, a circuit board holder with a circuit board mounted on it, a circuit board holder bracket having electrical contacts for the circuit board holder, and the part of the circuit board holder that holds the circuit board and rotates during operation. [Figure 5] This figure schematically and illustratively shows a base stage and a plurality of substrate holders arranged on the base stage, each holding a substrate, and a cross-sectional view of a shower head positioned above the base stage having the substrate holders and the substrate placed on them. [Figure 6] This diagram schematically and illustratively shows the underside of a showerhead divided into four sections, and the underside of a showerhead in which the precursor sections are further subdivided into arc-shaped segments having the same radial width. [Figure 7] This diagram schematically and illustratively shows the underside of a showerhead, which is divided into four sections, with the precursor section within the intermediate region being further subdivided into arc-shaped segments having the same radial width, and the outermost and innermost segments having a larger radial width than the segments in the intermediate region. [Figure 8]This is a schematic and illustrative cross-sectional view showing a section of a showerhead configured to supply a precursor onto a rotating substrate, or subdivided into multiple arc-shaped segments to alternately supply a precursor and gas or exhaust onto a rotating substrate, or subdivided into two arc-shaped segments, one of which is configured to supply a precursor onto a rotating substrate and the other to supply gas or exhaust. [Figure 9] This is a schematic and illustrative block diagram of a reaction apparatus for depositing one or more atomic layers of at least one material onto a substrate. [Figure 10] This figure schematically and illustratively shows (a) components of an X-ray microscope involved in generating submicrometer-resolution images of an object in micro-X-ray imaging mode, and (b) components of an X-ray microscope involved in generating nanometer-resolution images of an object in nano-X-ray imaging mode. [Modes for carrying out the invention]

[0047] Figure 1 schematically and illustratively shows the FZP100 in front view and cross-sectional view. The radius of the nth zone is indicated by reference numeral 114(r). n The width of the nth zone is indicated by the symbol 116(w). n The height of each zone and the overall height of FZP100 are indicated by the symbol 120. The radius, diameter, and height of the first zone 106 are indicated by the symbols 110, 112, and 120, respectively. The radius and width of the outermost zone 104 (the Nth zone) are indicated by the symbol 118 (r N ) and reference numeral 122(w NThe FZP100 comprises a first material 106 (black circles in the front view, hatched areas in the cross view) and a second material or void 108 (white circles) arranged alternately in concentric rings according to Fresnel's zone-plate law. Preferably, the first material 106 is a high-density material that absorbs X-rays of about 8 keV or higher and causes a strong phase shift, while the second material is less dense and exhibits higher penetration and a weaker phase shift for high-energy X-rays of about 8 keV or higher. As a result, the X-rays are diffracted by the alternately arranged zones 106 and 108, and so on. The zones 106 and 108 are spaced apart along the radius of the FZP, and diffracted X-rays of specific energies from a parallel X-ray beam constructively interfere at a predetermined focal point on the optical axis. Since the FZP functions like a lens for single-energy X-rays, an X-ray image can be generated by using the FZP in an imaging device.

[0048] The FZP100 can be used, for example, to focus X-rays with photon energies of 8 keV or higher. This is because the aspect ratio of the outermost zone 104 of the FZP100 is 650 or higher, and the zone width of the outermost zone 104 is w N This is possible because the wavelength is 30 nm or less. In other embodiments, the aspect ratio of the outermost zone 104 of FZP100 is 400 or more, and the zone width w of the outermost zone 104 is N The thickness is 50 nm or less. Furthermore, while FZP100 has a layer width accuracy Δw(RMS) / w of 0.01, in other embodiments the layer width accuracy Δw(RMS) / w may be less than 0.01. Also, in FZP100 the roundness R of each zone is ba=c=(1 / 2)w N However, the degree of roundness R of each zone is ba = c ≤ (1 / 2)w N That's fine.

[0049] Figure 2 is a schematic and illustrative plan view and perspective view of the circular core substrate 200, where reference numeral 202 denotes the radius b of the circumscribed circle and reference numeral 201 denotes the radius a of the inscribed circle. The degree of roundness R is defined as R = a / b.

[0050] High roundness means that the roundness is as close as possible to 1 (a perfect circle). That is, preferably, the difference between the radii of the circumcircle and the incircle, 203 (ba), is less than 100 nm. 0 ≤ ba = c ≤ (1 / 2)w N That is the case.

[0051] R is at least, or

number

[0052] Figure 3 is a schematic and illustrative perspective view showing a cylindrical core substrate 300 and a tapered core substrate 310, including but not limited to linear, parabolic, and curvilinear tapers. Substrates 300 and 310, like substrate 200 described in Figure 2, have two-dimensional roundness.

number

number

number

[0053] Tapered substrates, for example, Sanli et al.'s "3D Nanoprinted Plastic Kinoform" As described in "X-Ray Optics" (Advanced Materials 30, 1802503, 2018), structures in which the diameter changes linearly or parabolicly along the principal axis can provide higher diffraction efficiency.

[0054] Figure 4 schematically and illustratively shows a two-part substrate holder having a fixed substrate holder mounting mechanism, in cross-sectional view 400 and plan view 410 on a base stage 402, a retaining bracket 404 having a groove 406 for receiving the detachable substrate holder portion shown in Figures 430, 450 or 440, 460, and electrical contacts 408 for the detachable substrate holder portion. The detachable substrate holder portion shown in cross-sectional view 430 and plan view 450 holds the substrate 433 on a detachable substrate holder plate 435 using substrate rotation retainers 434 provided at both ends of the substrate, and rotates the substrate during operation. One side of the substrate rotation retainer 434 is attached to a bearing 436, and the opposite side is attached to a substrate holder drive mechanism, which is implemented as a rotation drive unit 432 equipped with electrical contacts 431. The rotation drive unit 432 is configured to rotate the substrate 433 around a substrate rotation axis 437. Preferably, the rotational drive unit is sealed to avoid the generation of particles.

[0055] The detachable substrate holder shown in the cross-sectional view 440 and the plan view 460 holds the substrate 433 on the detachable substrate holder plate 435 using a substrate rotation retainer 442 provided at one end of the substrate, and rotates the substrate during operation. The substrate rotation retainer 442 is attached to a substrate holder drive mechanism which is implemented as a rotation drive unit 432 equipped with electrical contacts 431. The rotation drive unit 432 is configured to rotate the substrate 433 around the substrate rotation axis 437.

[0056] The substrate 433 can be configured as one of the substrates 300, 310, 320, or 330 described with reference to Figure 3. The substrate holder system described with reference to Figure 4 may be used, for example, as the substrate holder 502 described with reference to Figure 5, in combination with the reactor 900 described with reference to Figure 9.

[0057] Figure 5 is a schematic and illustrative perspective view 500 showing a base stage 501 and a plurality of substrate holders 502 positioned on the base stage 501, each holding a substrate 504. A cross-sectional view 510 shows a shower head 506 positioned above the base stage 501, which has substrate holders 502 on which the substrate 504 is placed. The shower head 506 may be configured similarly to the shower heads 600 and 700 described with reference to Figures 6 and 7, respectively.

[0058] The base stage 501 can be rotated around the base stage rotation axis 508. The substrate 504 is mounted on substrate holders 502 arranged in a circle on the base stage 501. The substrate 504 can be rotated around the substrate rotation axis 510 by each substrate holder 502. The substrate rotation axis 510 is perpendicular not only to the base stage rotation axis 508 but also to the gas flow and precursor flow from the showerheads 506. The precursor and gas supply showerheads 506 are positioned above the substrate 504 and the base stage 501 at a variable distance 512(d). A distance adjustment unit may be provided as an option to adjust the distance 512(d).

[0059] Figure 6 schematically and illustratively shows the underside of a showerhead 600 divided into four sections 602, 604, 606, and 608, and the underside of a modified example 620 of the showerhead 600, where two precursor or reaction gas segments 602 and 604 are further subdivided into arc-shaped segments 610 and 612 having the same radial width. Each section 602, 604, 606, and 608 is connected to its own dedicated gas or precursor supply line. The supply of gas and precursor is controlled via the gas and / or precursor mixing manifold of the showerhead 600. A low vacuum (or purge gas or curtain gas) section 618 may be provided between the individual sections 602, 604, 606, and 608. By using the four sections 602, 604, 606, and 608, a precursor or purge gas flow can be supplied to the substrate below at a continuous, pulsed, or time-varying flow rate. In particular, the purge gas flow and the precursor are provided in adjacent sections, for example, the first section 602 and the third section 606, which provide the purge gas; the second section 604 and the fourth section 608, which provide two different types of precursors, for example, the second section 604 which provides an organic or inorganic precursor of oxides, metals, or nitrides; and the fourth section 608 which provides an oxidant, hydrogen plasma, or nitrogen precursor for depositing oxides, metals, or nitrides, for example, ammonia, nitrogen gas, or nitrogen plasma.

[0060] Furthermore, each section 602, 604, 606, and 608 is surrounded by a trench 618 to prevent mixing of adjacent chemicals, which is connected to an exhaust (vacuum) or purge gas and provides a barrier between sections 602, 604, 606, and 608. Two sections 602 and 606 are configured, for example, in an ALD process, to supply gas A and gas B, which may be the same as or different from gas A.

[0061] Furthermore, as a variation of the showerhead 620, the section 604 supplying precursor A and the section 608 supplying precursor B can be further divided into n arcuate subsegments 610, 612 having a constant radial width, which are shown as alternating arcuate black and hatched quadrant rings. Each arcuate subsegment 610 (for section 604), 612 (for section 608) can be individually controlled and switched to gas, precursor, or exhaust. This allows for rotationally symmetric patterning and / or deposition with respect to a substrate held by a substrate holder, as illustrated with reference to Figure 4, for example.

[0062] Figure 7 schematically and illustratively shows the undersides of showerhead 700 and showerhead 720, which are divided into four sections 702, 704, 706, and 708. The precursor sections 704 and 708 of showerhead 700 are further subdivided into arcuate subsegments 712 having the same radial width within an intermediate region 710. The outermost segment 714 and the innermost segment 716 have a larger radial width than the segments 712 within the intermediate region 710. A low vacuum (or purge gas or curtain gas) section 718 may be provided between the individual sections 702, 704, 706, and 708.

[0063] Figure 8 is a schematic and illustrative cross-sectional view showing a portion of showerheads 800, 810, 820, and 830 configured to supply a precursor onto a rotating substrate 802. The showerheads 800, 810, 820, and 830 are divided into multiple arc-shaped segments for alternately supplying a precursor 814 and gas or exhaust 812 onto the rotating substrate 802. Subdividing the showerhead sections into arc-shaped segments, as shown in the example in Figure 8, allows for controllable modification of the functionality of lateral deposition. For example, by changing the functionality of the arc-shaped segments and / or the distance 833(d) between the substrate and the showerhead over time, various different width profiles 816 of concentric rings (e.g., zones of FZP) can be achieved.

[0064] Figure 9 is a schematic and illustrative block diagram of a reactor 900 used in the production of FZP, for example, as described with reference to Figure 1, for depositing one or more atomic layers of at least one material onto a substrate. For example, the reactor 900 can be operated to perform an ALD process. For this purpose, the reactor 900 comprises a reaction chamber 902, an exhaust vacuum pump 904, a load lock 906, and a base stage 908 and shower heads 910 located within the reaction chamber 902. The base stage can be configured as described with reference to Figure 5 and comprises one or more substrate holders as described with reference to Figure 4 and / or Figure 5. The shower heads 910 are preferably configured as shower heads 600, 620, 700, and 720 as described with reference to Figures 6 and 7, respectively. The reactor 900 further comprises a gas and precursor manifold inlet 912 with connections to a vacuum pump 914, a precursor source 916, and a gas source 918.

[0065] ALD operates within a so-called ALD temperature window that exceeds the precursor saturation threshold, within which the growth rate does not depend on the amount of precursor introduced, growth becomes self-limiting, and the overall layer width depends only on the number of ALD cycles. Since the precursor is introduced into the reaction chamber by pulses, a certain pulse duration is required to achieve saturation. For example, for the deposition of oxides, metals, or nitrides, an ALD cycle typically comprises four subcycles: firstly, an organic or inorganic precursor for the oxide, metal, or nitride; secondly, a purge step; thirdly, an oxidizing agent, hydrogen plasma, or a nitrogen precursor such as ammonia, nitrogen gas, or nitrogen plasma; and fourthly, a purge step in which typically less than one single atomic layer of metal oxide is produced per cycle. GPC is generally limited by the size and reactivity of the precursor.

[0066] The reactor 900, equipped with a base stage rotation axis and an additional substrate rotation axis, can achieve cycle-controlled three-dimensional conformal growth with higher deposition rates, as well as the atomic layer width accuracy and roughness (RMS) required for FZP suitable for photon energies of 8 keV or higher. In the reactor 900, one rotation of the base stage is defined as one ALD cycle, during which the substrate rotates under each of the four sections. The pulse time is determined by the time the substrate resides under each showerhead section. The growth rate can be converted from GPC to growth rate by multiplying the GPC by the rotation frequency of the base stage.

[0067] During the operation of the reactor 900 performing the ALD process, the base stage 908 is heated and rotated for a certain period of time. A substrate holder (not shown) is placed on the base stage 908, on which a substrate (not shown), such as fiber, is attached for the deposition process. The substrate holder is arranged on the base stage 908 in a circular pattern. The substrate holder can be rotated, for example, independently of the base stage 908. Preferably, in addition to the heated base stage 908, the substrate holder can be heated individually.

[0068] When FZP is manufactured using the ALD process, layers of material A and material B, which have different physical properties, are deposited alternately. Materials A and B are, for example, (metal) oxides, (metal) nitrides, or metals. The thickness of each deposited layer and the resulting zone width, as well as the total number of layers or zones in the FZP, each follow the Fresnel zone law. Preferably, materials A and B are selected such that material A has appropriate X-ray contrast and / or phase shift relative to material B in the desired photon energy range, and at least one of material A and / or material B has self-smoothing properties during deposition, such as Al2O3. The ALD process can be useful when it is necessary to adaptively control deposition parameters based on sensor inputs such as quartz microbalance, reflectance measurements, reflection anisotropy spectroscopy (RAS), and spectroscopic ellipsometry.

[0069] In particular, the ALD process for FZP production using the reactor 900 may include one or more of the following steps: - Steps include supplying a substrate, for example, glass fibers or metal wires having high roundness, i.e., straight or tapered solid fibers, as described in Figure 3. - For example, a chemical pre-cleaning step using aqua regia, piranha solution, Chromel solution, or degreasing with organic solvents. - A step of mounting the circuit board into a circuit board holder that can further rotate the circuit board axis, - For example, a system cleaning step using a CO2 snow gun, - A step of placing the substrate on a rotating and heated substrate holder and transferring it into the reaction chamber, - A step of fixing the board rotation axis to the board holder itself, - For example, surface functionalization steps to promote material growth, such as OH, NH, and C surface termination treatments. - A step of alternately depositing layers of oxide A and oxide B until the desired zone width is obtained. - A step of continuously rotating a substrate around the base stage rotation axis while alternately, preferably continuously flowing a first precursor or reaction gas, a purge gas or gas-containing stream, and a second precursor or reaction gas (e.g., an oxidizing agent) beneath it, and switching the gas stream according to the composition of oxide A and oxide B. - A step of modifying the deposition profile along the substrate in order to change the function (precursor, gas, or exhaust) of the arc-shaped subsegments in the two precursor sections and the distance d from the substrate to the showerhead, thereby changing the deposition layer thickness along the central axis of the substrate, and - This is the step of covering the substrate (within the system) with a protective coating (e.g., SiO2).

[0070] To obtain a higher phase contrast, an additional metal layer can be deposited instead of the oxide. In this case, the FZP consists of a rotationally symmetric substrate, such as glass fibers or metal wires, with alternating layers of metal and oxide. Here, the oxidizing agent precursor is preferably replaced by a gas stream from a hydrogen plasma source.

[0071] After the ALD process for FZP manufacturing is completed, the following steps may be performed. - A step of slicing the coated substrate to a desired FZP height, for example, using a focused ion beam. - A step of further polishing the sides of the FZP mechanically or chemically, and - The step of mounting the FZP onto a suitable X-ray transparent film, for example, Si3N4. That is the case.

[0072] Figure 10 schematically and illustratively shows the components of the X-ray microscope 1000 that are involved in generating submicrometer-resolution images of an object in micro-X-ray imaging mode, and the components of the X-ray microscope 1000 that are involved in generating nanometer-resolution images of an object in nano-X-ray imaging mode.

[0073] The X-ray microscope 1000 comprises an X-ray source 1002 configured to emit X-rays for micro-X-ray imaging mode, a two-dimensional X-ray detector 1006 for imaging, a four-axis stage 1010 for moving the sample object, and a five-axis stage 1012 for the detector. The figure also shows a sample object 1014, which is not part of the X-ray microscope 1000. When switching to nano-X-ray imaging mode, the first X-ray optical element 1016 on the five-axis stage 1018 and the second X-ray optical element 1020 on the six-axis stage 1022 are moved into the X-ray beam path 1024 by the operation of arrows 1030 and 1031, respectively. The second X-ray optical element 1020 is an FZP configured as, for example, the FZP 100 described with reference to Figure 1.

[0074] Equipped with two imaging modes—micro X-ray imaging mode and nano X-ray imaging mode—the X-ray microscope 1000 combines high spatial resolution with deep object penetration. The small-spot, high-energy X-ray source provides equally high penetration in both imaging modes, enabling seamless imaging from micro to nano without cutting or special sample preparation.

[0075] In micro-X-ray imaging mode, the imaging subsystem of the X-ray microscope 1000 images a two-dimensional image of the sample object with micrometer resolution. As a use case, this resolution is advantageous and useful for identifying regions of interest, such as defects located deep within the sample object, and then selecting two-dimensional or three-dimensional regions of interest for imaging at nanoscale resolution in nano-X-ray imaging mode. The micro-X-ray imaging subsystem also shares the X-ray source, sample object manipulator, X-ray detector, and system control and GUI interface with the nano-X-ray imaging subsystem.

[0076] In nano-X-ray imaging mode, the nano-X-ray imaging mode subsystem generates a two-dimensional image of the sample object imaged with nanometer-scale resolution. Use cases include generating high-resolution two-dimensional images necessary for clearly visualizing and identifying defects such as microcracks in microsolder bumps within vertically integrated microchips and chiplets, and voids and delaminations within through electrodes. The nano-X-ray imaging mode subsystem shares the X-ray source, sample object manipulator, X-ray detector, and computer control and interface (GUI) with the micro-X-ray imaging mode subsystem. The nano-X-ray imaging mode subsystem integrates the function of inserting the two X-ray optical elements required for nanoimaging into the beam path into the X-ray microscope 1000. When switching between micro-X-ray imaging mode and nano-X-ray imaging mode, the first and second X-ray optical elements are moved into or out of the beam path.

[0077] The X-ray microscope 1000 operates at monochromatic high-photon energies exceeding 8 keV using a high-power X-ray source, such as a liquid metal jet X-ray source excited by conventional electron excitation or laser-induced plasma methods, thereby enabling penetration through thick objects. Using FZP, it is possible to generate nanoscale resolution images while maintaining object penetration. In micro-X-ray imaging mode, the microscope can move over the sample object to generate low-resolution 2D or 3D overview images of the sample object. Switching between microscale and nanoscale imaging is seamless and transparent for the user without transferring the sample object to another instrument or performing navigation procedures. To transition from projection-based microscale imaging mode to nanoscale imaging mode, the first X-ray optical element 1016 and the second X-ray optical element 1020 are inserted into the beam path 1024 (arrows 1030, 1031). For example, adjustments due to mechanical or thermal instabilities can be handled by neural network-assisted alignment, or by closed-loop sensor-based alignment systems such as interferometers, capacitive sensors, or image sensors.

[0078] Therefore, it is preferable to provide machine learning-based procedures to assist the user in setting up the X-ray microscope 1000 and in multiscale image and data analysis. Using the X-ray microscope 1000 can reduce or avoid complex, time-consuming, error-prone, and much more expensive workflows. A control unit with a trained neural network can generate clear, high-resolution three-dimensional images of the region of interest with minimal artifacts using data from both micro-X-ray imaging mode and nano-X-ray imaging mode. In particular, by incorporating a neural network-based algorithm into the three-dimensional reconstruction algorithm configured by the control unit, image artifacts caused by experimental errors, such as component contamination and thermal drift of sample objects and components, can be reduced, and image acquisition time can be shortened by introducing a surveillance tomography reconstruction technique. Preferably, the neural network of the control unit is trained to control the movement of the first X-ray optical element and the second X-ray optical element into and out of the beam path in order to switch between micro-X-ray imaging mode and nano-X-ray imaging mode, and to align the first X-ray optical element and the second X-ray optical element.

[0079] Preferably, the X-ray microscope 1000 provides a small spot of 50 μm or less, a high-energy X-ray source of 8 keV or more, a high-photon flux, and high brightness. Preferably, the X-ray microscope 1000 provides monochromatic or monochromatized X-rays.

[0080] The second X-ray optical element, i.e., the FZP, may be positioned on a linearly moving or rotating lens turret, and may be switched between different optical elements, such as a multilayer Laue lens.

[0081] Preferably, the first X-ray optical element and the second X-ray optical element are configurable / interchangeable to correspond to different photon energies covering at least the range of 8 to 25 keV.

[0082] Preferably, the first X-ray optical element has a monochromatic function and, for example, the first X-ray optical element is coated or uncoated and may include two two-dimensional focusing mirrors, elliptical mirrors, capillaries, or focusing optics. Preferably, the photon energy is adjustable via a monochromator, for example, in the range of at least 8 to 25 keV. By using a focusing monochromator, a single-wavelength image with a specific photon energy bandwidth (e.g., (E / ΔE) > 100) can be obtained. To adjust the photon energy with the monochromator and maintain a constant irradiation image position on the sample object, it may be necessary to appropriately move other X-ray optical elements and the sample object position. This results in an energy-resolved image, for example, each pixel on the detector can record an X-ray absorption spectrum. The X-ray microscope 1000 may include an adaptive, closed-loop, or neural network-based positioning system, for example using a laser interferometer, as part of a control unit to guide the transition from micro-X-ray imaging mode to nano-X-ray imaging mode. Multiple axes in multiple elements may be used to compensate for temperature fluctuations. The X-ray microscope 1000 preferably further comprises a fully sealed cabinet. Preferably, the X-ray microscope 1000 is controllable according to the temperature and humidity inside the X-ray cabinet. For example, the X-ray microscope 1000 may be equipped with an internal temperature and / or air distribution system.

[0083] In addition to or instead of the above, the first optical X-ray element 1016 may be a double-mirror monochromator. The photon energy is preferably changeable using the monochromator, and as a result, a monochromatic two-dimensional image can be obtained, for example, on the detector 1006. By scanning the photon energy within the allowable window of the second X-ray element 1020, a laterally resolved X-ray absorption spectrum (XAS) can be obtained. Multiple second X-ray elements can be used to cover a wide range of energies, for example, the absorption edge, and these are preferably mounted on a rotating lens turret.

[0084] In the claims, the word “including” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude the plural form. A single unit or device may perform the functions of multiple elements described in a claim. The fact that certain means are described in different dependent claims does not mean that these means cannot be used advantageously in combination. The reference numerals in the claims should not be construed as limiting the scope of the invention.

Claims

1. A reaction apparatus for depositing one or more atomic layers of at least one material onto a substrate, Equipped with a reaction chamber, The reaction chamber is A showerhead having at least one gas outlet configured to supply a gas stream of at least one precursor or at least one reaction gas or at least one component of at least one material, A base stage that can rotate around the base stage rotation axis, A reaction apparatus comprising: at least one substrate holder, which is positioned on the base stage and configured to rotate the substrate around the substrate rotation axis in such a manner that the base stage rotation axis and the substrate rotation axis are inclined relative to each other; and

2. The reaction apparatus according to claim 1, wherein at least one of the substrate holders comprises a substrate holder drive mechanism comprising a motor and a substrate mounting support portion connected to the motor for holding the substrate and rotating the substrate around the substrate rotation axis.

3. The reaction apparatus according to claim 1 or claim 2, comprising a plurality of substrate holders arranged on the base stage, wherein each of the plurality of substrate holders is independently rotatable around its own substrate rotation axis relative to the base stage.

4. The reaction apparatus according to any one of claims 1 to 3, wherein at least one of the substrate holders is detachably attached to the base stage.

5. The reaction apparatus according to any one of claims 1 to 4, wherein the substrate holder is configured to rotate the substrate such that the substrate rotation axis is substantially perpendicular to the base stage rotation axis.

6. The reaction apparatus according to any one of claims 1 to 5, comprising a base stage heating element capable of heating the base stage, or a radiation source that supplies infrared rays, wherein the radiation source is configured and arranged to supply infrared heating spots so that the substrate held in the substrate holder is heated in a spatially localized area.

7. The reaction apparatus according to any one of claims 1 to 6, comprising a substrate holder heating element arranged and adapted to heat at least one of the substrate holders.

8. The reaction apparatus according to any one of claims 1 to 7, wherein the showerhead is spatially divided into four regional sections, the first section is provided with a first gas outlet for supplying a first gas stream containing a first precursor or reaction gas to be deposited and / or at least one component of the material to be deposited, the second section is provided with a second gas outlet for introducing a first purge gas, the third section is provided with a third gas outlet for supplying a second gas stream containing a second precursor or reaction gas to be deposited and / or at least one component of the material to be deposited, and the fourth section is provided with a fourth gas outlet for introducing a second purge gas.

9. A method for depositing one or more atomic layers of at least one material onto a substrate using a reaction apparatus according to any one of claims 1 to 8, - The steps of placing the substrate on at least one of the substrate holders, - The step of placing the substrate holder together with the substrate on the base stage in the reaction chamber, - A step of introducing a gas stream containing at least one of the precursors, a reaction gas, and / or at least one component of the material into the reaction chamber through at least one of the gas outlets, - The substrate is rotated together with the base stage around the base stage rotation axis, and further, the substrate is rotated together with the substrate holder around the substrate rotation axis, and the base stage rotation axis and the substrate rotation axis are inclined relative to each other, step and A method comprising the step of depositing one or more atomic layers of at least one of the materials and / or at least one of the components of the at least one of the materials onto the substrate.

10. The method according to claim 9, wherein alternating layers of a first material and a second material having controlled thickness are deposited on the substrate in a concentric ring shape, and the first material and the second material differ in at least one physical property.

11. The method according to claim 9 or claim 10, wherein at least one material is deposited at a deposition rate of 1 nm or more per minute, preferably 10 nm or more per minute.

12. Before or after placing the substrate holder together with the substrate on the base stage in the reaction chamber or pre-chamber, CO ２ The method according to any one of claims 9 to 11, comprising cleaning the substrate using a snow gun, an ozone source and / or generator, a plasma source, sputtering, or etching.

13. Use of a reaction apparatus according to any one of claims 1 to 8 for manufacturing a Fresnel zone plate, The Fresnel zone plate comprises a first material and a second material arranged alternately in a concentric ring shape according to the Fresnel zone plate law, the outermost zone having an aspect ratio of 50 or more and a zone width of 50 nm or less, and / or the Fresnel zone plate having a layer width accuracy Δw(RMS) / w of 0.01 or less, and the roundness of each zone being R≧1-(1 / 2)W Ｎ / b or greater, where w Ｎ The width of the outermost zone is used, and / or the aspect ratio of the outermost zone is 50 or greater.

14. An X-ray microscope that generates a magnified image of an object using X-rays, - An X-ray detector that detects X-rays supplied from an X-ray source and transmitted through an object, - A first X-ray optical element that can be automatically moved in and out of the X-ray beam path between the X-ray source and the object, - A second X-ray optical element, which is a Fresnel zone plate comprising a first material and a second material arranged alternately in a concentric ring shape according to the Fresnel zone plate law, wherein the Fresnel zone plate has an aspect ratio of 50 or more in the outermost zone, a zone width of 50 nm or less in the outermost zone, and / or the Fresnel zone plate has a layer width accuracy Δw (RMS) / w of 0.01 or less, and the roundness of each zone is R ≥ 1 - (1 / 2) w Ｎ / b is above, and here, w Ｎ The width of the outermost zone is and / or the aspect ratio of the outermost zone is 50 or more, and the second X-ray optical element is capable of automatically moving in and out of the X-ray beam path between the object and the X-ray detector, - A control unit configured to control the automatic movement of the first X-ray optical element and the second X-ray optical element into and out of the beam path, and to adjust the positions of the first X-ray optical element and the second X-ray optical element with respect to the beam path, An X-ray microscope capable of moving the first X-ray optical element and the second X-ray optical element outside the beam path in order to generate an image of the object with micrometer resolution in micro X-ray imaging mode, and capable of moving the first X-ray optical element and the second X-ray optical element inside the beam path in order to generate an image of the object with nanometer resolution in nano X-ray imaging mode.

15. The X-ray microscope according to claim 14, further comprising a positioning system arranged and configured to guide the transition from the micro-X-ray imaging mode to the nano-X-ray imaging mode and the reverse transition.

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