CN118328914B - Small-angle X-ray scattering measurement device and method based on multi-beam incidence - Google Patents

Abstract

The present invention provides a small-angle X-ray scattering measurement device and method based on multi-beam incidence, the device comprising: an X-ray source (1); a focusing lens (2); an aperture group (3), comprising a beam selector (310) having a plurality of aperture apertures (311), wherein the focused X-ray beam passes through the plurality of aperture apertures to selectively obtain a plurality of incident beams, wherein the plurality of aperture apertures are respectively used to adjust the divergence angles of the plurality of incident beams; a sample stage (4), used to carry the sample, wherein the plurality of incident beams are irradiated onto a specified position on the sample surface at different incident angles relative to the normal direction of the sample; a detector (5), receiving a plurality of detection beams emitted from the sample after the plurality of incident beams are scattered by the sample, so as to obtain the spatial distribution of the scattered light intensity of the plurality of detection beams; and a data processing system (6), which determines the three-dimensional structural information of the sample based on the spatial distribution of the scattered light intensity and the respective incident angles of the plurality of incident beams.

Description

Small-angle X-ray scattering measurement device and method based on multi-beam incidence

Technical Field

The present invention relates to the field of X-ray analysis, and in particular to a small-angle X-ray scattering measurement device and method based on multi-beam incidence.

Technical Background

With the development of the integrated circuit industry, the characteristic size of chips has gradually decreased, and more and more complex three-dimensional structures have also appeared. In order to improve the product yield during the production process, it is necessary to perform measurements at various steps during the semiconductor manufacturing process to detect defects on the wafer. Through measurement, structural parameter information such as the critical dimension (CD) and film thickness of the chip structure can be obtained.

Traditional measurement methods mainly use visible light, which has poor penetration and is difficult to obtain three-dimensional structural information of high aspect ratio materials. At the same time, due to its long wavelength, it is difficult to obtain high measurement accuracy. Although atomic force microscopy (AFM) and scanning tunneling microscopy (STM) can obtain atomic-level measurement accuracy, they require a lot of time to scan and can only obtain surface structural information of the chip. Scanning electron microscopy (SEM) can also achieve high measurement resolution, but it is also unable to penetrate the sample to obtain internal structural information. In order to overcome the penetration depth problem, a series of destructive sample structure measurement methods have been developed, such as transmission electron microscopy (TEM), which destructively segments the sample to obtain structural parameters at any longitudinal position. However, this technology requires the destruction of the sample and the imaging time is long, making it difficult to apply to the actual production process of the chip.

On the other hand, the wavelength of X-rays is in the range of 0.001nm to 10nm, which is much smaller than the wavelength of visible light, and can also obtain higher measurement resolution. At the same time, X-rays have strong penetration and can obtain three-dimensional structural information inside the chip. Transmission small angle x-ray scattering (T-SAXS) uses higher energy X-rays to irradiate the sample, obtains scattering patterns at different rotation angles by rotating the sample, and then reconstructs the three-dimensional structural information of the sample through an algorithm. This method usually uses X-rays with a wavelength of about 0.1nm, which is suitable for measuring high aspect ratio (HAR) features, such as HAR holes or grooves manufactured in semiconductor wafers, to obtain various parameter information such as critical dimensions, tilt, ellipticity, overlay error, etc., and performs measurement of structural features and other characteristics based on analyzing the intensity of X-rays scattered from the wafer at different angles. It has the characteristics of non-contact, non-destructive, and statistical averaging. However, due to the small interaction cross section between X-rays and matter and the weak signal, the measurement speed is limited by the flux of miniaturized desktop X-ray sources.

Currently, KLA-Tencor's patent application for "X-ray scattering measurement and metrology for high aspect ratio structures" (application number CN201680070562.0) involves the use of transmission small-angle X-ray scattering technology to measure a vertical manufacturing device for high aspect ratio structures. However, the patent uses a single angle of light incident on the sample, and the ray flux utilization rate is low, making it difficult to achieve rapid measurement.

Prior art literature

Patent document 1: CN201680070562.0

Summary of the invention

Technical Problems to be Solved by the Invention

The purpose of the present invention is to provide a small-angle X-ray scattering measurement device and method based on multi-beam incidence, which adopts a large-size focusing mirror to collect X-rays at more angles, and obtains multiple incident light beams through multiple apertures, so that the X-rays emitted by the X-ray source have different incident angles at the sample position, and the scattering patterns corresponding to multiple incident angles can be obtained on the detector at the same time. Therefore, the simultaneous detection of information at multiple angles can more effectively utilize the flux of the X-ray source to improve the measurement speed of the sample. At the same time, the introduction of more angle information can effectively improve the measurement accuracy.

Technical means adopted by the present invention

In order to achieve the above-mentioned object, the present invention provides a small-angle X-ray scattering measurement device based on multi-beam incidence, which is used to measure the three-dimensional structural information of a sample. The small-angle X-ray scattering measurement device includes: a small-angle X-ray scattering measurement device based on multi-beam incidence, which is used to measure the three-dimensional structural information of a sample, characterized in that it includes: an X-ray source, which emits an X-ray beam; a focusing mirror, which focuses the X-ray beam; an aperture group, which includes a beam selector with multiple aperture apertures, and the X-ray beam focused by the focusing mirror passes through the multiple aperture apertures to selectively obtain multiple incident beams, and the multiple aperture apertures are respectively used to adjust adjusting the divergence angle of the multiple incident light beams; a sample stage, which is used to carry the sample, and the multiple incident light beams are irradiated to specified positions on the surface of the sample at different incident angles relative to the normal direction of the sample; a detector, which is arranged on the side of the sample opposite to the X-ray source side, and receives the multiple detection light beams emitted from the sample after the multiple incident light beams are scattered by the sample, so as to obtain the spatial distribution of the scattered light intensity of the multiple detection light beams; and a data processing system, which determines the three-dimensional structural information of the sample based on the spatial distribution of the scattered light intensity recorded by the detector and the incident angles of the multiple incident light beams.

Preferably, the focal spot divergence angle of the X-ray beam is at least 1 degree.

Preferably, the focusing mirror has a monochromatic frequency selection function.

Preferably, the focal spot position of the focusing mirror is any position from 10 cm in front of the sample to the detector surface.

Preferably, the focusing mirror is provided with a direct light blocker for blocking the X-ray beam directly passing through the focusing mirror.

Preferably, along the incident direction of the X-ray beam, the straight light blocker is arranged at any position between 10 cm in front of the focusing mirror and 10 cm behind the focusing mirror.

Preferably, the aperture group further includes: a field aperture, used to adjust the size of the irradiation area of the incident light beam irradiating the surface of the sample; and a stray light elimination aperture, which is arranged between the beam selector and the field aperture and is used to eliminate system stray light.

Preferably, the irradiation areas of the multiple incident light beams on the surface of the sample have the same size.

Preferably, the incident directions of the multiple incident light beams have an angle with the normal direction of the sample.

Preferably, the incident direction of one of the multiple incident light beams is the normal direction of the sample.

Preferably, the sample stage is capable of rotating the sample by at least 20 degrees around an axis perpendicular to the normal direction of the sample, and a resolution of the rotation angle is less than 5 degrees.

Preferably, the aspect ratio of the sample is greater than or equal to 10, and the characteristic size is less than or equal to 200 nm.

The present invention also provides a small-angle X-ray scattering measurement method based on multi-beam incidence, which includes the following steps: adjusting the multiple aperture apertures of the beam selector in the aperture group so that the X-ray beam emitted by the X-ray source, after being focused by the focusing mirror, selectively obtains multiple incident light beams through the beam selector, and the multiple incident light beams are irradiated to specified positions on the surface of the sample at different incident angles relative to the normal direction of the sample, and the multiple aperture apertures are used to adjust the divergence angles of the multiple incident light beams; using the detector to receive the multiple detection light beams emitted from the sample after the multiple incident light beams are scattered by the sample, so as to obtain the spatial distribution of the scattered light intensity of the multiple detection light beams; and the data processing system determines the three-dimensional structure information of the sample based on the spatial distribution of the scattered light intensity of the multiple detection light beams and the information of the incident angles of each of the multiple incident light beams.

Technical Effects

According to the small-angle X-ray scattering measurement device and method based on multi-beam incidence of the present invention, a large-size focusing mirror is used to collect X-rays at more angles, and multiple incident light beams are obtained through multiple apertures, so that the X-rays emitted by the X-ray source have different incident angles at the sample position, and the scattering patterns corresponding to the multiple incident angles can be obtained on the detector at the same time. Therefore, the simultaneous detection of information at multiple angles can more effectively utilize the flux of the X-ray source to improve the measurement speed of the sample. At the same time, the introduction of more angle information can effectively improve the measurement accuracy.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic structural diagram of a small angle X-ray scattering (SAXS) measurement device 10 according to Embodiment 1 of the present invention;

2 is a schematic diagram of a beam selector 310 and its variants in a small angle X-ray scattering (SAXS) measurement device 10 according to Embodiment 1 of the present invention;

FIG3 is a schematic structural diagram of a small angle X-ray scattering (SAXS) measurement device 20 according to Embodiment 2 of the present invention;

FIG4 is a schematic diagram of an image of the intensity of X-ray scattered light sensed by the detector 5 according to Embodiment 1 of the present invention;

5 is a schematic diagram of an image of the intensity of X-ray scattered light sensed by the detector 5 after the sample 4 to be tested is rotated by a certain angle according to Embodiment 1 of the present invention;

6 is a schematic diagram of an image of the intensity of X-ray scattered light sensed by the detector 5 after the sample 4 to be tested is rotated by another angle according to Embodiment 1 of the present invention;

FIG7 is a schematic diagram of an image of the intensity of X-ray scattered light sensed by the detector 5 according to Embodiment 2 of the present invention;

FIG. 8 is a flow chart of a small angle X-ray scattering (SAXS) measurement method according to the present invention.

DETAILED DESCRIPTION

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the invented product is usually placed when in use, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "disposed" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

<Small-angle X-ray scattering (SAXS) measurement device>

<Example 1>

FIG1 is a schematic diagram of the structure of a small-angle X-ray scattering (SAXS) measurement device 10 according to Embodiment 1 of the present invention. For the sake of simplicity, the small-angle X-ray scattering (SAXS) measurement device 10 is also referred to as "SAXS measurement device 10" hereinafter, and measures the structural features of a sample (in this example, the sample 4 to be measured, such as a semiconductor wafer) by using X-ray scattering measurement technology. In this article, the term "small angle" refers to scattering within a small angle range within 5° close to the original beam.

In addition, the normal direction of the sample 4 to be tested, that is, the direction of travel of the X-ray beam is set as the z direction (z-axis, the left and right direction in the paper in the figure), the up and down direction in the paper perpendicular to the z-axis is set as the y direction (y-axis), and the direction perpendicular to the z-axis and the x-axis, that is, the direction perpendicular to the paper, is set as the x direction (x-axis), thereby establishing an xyz space coordinate system, as shown in Figure 1.

The SAXS measurement device 10 includes a light source 1 , a focusing lens 2 , an aperture group 3 , a sample to be measured 4 , a detector 5 , and a data processing system 6 .

As an X-ray source for generating X-rays, the light source 1 is configured to emit X-rays having suitable energy (e.g., >10 eV) to pass through the wafer of the sample to be tested 4. The X-rays emitted by the light source 1 have a wavelength equal to or less than 0.1 nm, and a focal spot divergence angle of at least 1 degree.

The light source 1 can be any one of a particle acceleration radiation source, a liquid target anode radiation source, a rotating anode radiation source, a fixed solid anode radiation source, a micro-focusing radiation source, a micro-focusing rotating anode radiation source and an inverse Compton scattering radiation source.

The X-rays emitted from the light source 1 are irradiated onto the focusing mirror 2 and are focused. The focusing mirror 2 is, for example, a circularly symmetrical reflector coated with a multilayer film, which focuses the incident X-rays to the irradiation position through reflection from the concave surface. At the same time, by designing the film thickness, refractive index, reflectivity, etc. of the multilayer film, the incident X-rays are crystal-diffracted in the multilayer film, and monochromatic X-rays of the required wavelength (frequency) are screened out, that is, the effect of monochromatic frequency selection can be achieved. The focusing mirror 2 can be any one of a Schwarzschild optical device, a Wolter optical device, and an ellipsoidal optical device.

The position of the focused spot of the focusing mirror 2 can be adjusted according to the measurement conditions, for example, it can be any position from 10 cm in front of the sample 4 to the surface of the detector 5. Here, "front" refers to the -z direction side of the sample 4 (the opposite direction of the traveling direction of the X-ray beam), that is, the left side in Figure 1.

In addition, the focusing mirror 2 has a relatively large collection angle, which corresponds to the focal spot divergence angle of the X-rays emitted by the light source 1 and is at least 1 degree.

In Fig. 1, a direct light blocker 201 is also provided at the entrance side of the focusing mirror 2 to absorb the direct X-rays and retain only the X-rays reflected by the focusing mirror 2. The direct light blocker 201 can be provided at any position from 10 cm in front of the focusing mirror 2 to 10 cm behind the focusing mirror.

The X-ray beam after monochromatic focusing by the focusing mirror 2 is emitted from the focusing mirror 2 . The focusing mirror exit spot 101 in FIG. 1 represents the spot of the X-ray beam after being emitted from the focusing mirror 2 . The exit beam having the focusing mirror exit spot 101 enters the aperture group 3 .

In the first embodiment, the aperture group 3 includes a beam selector 310 , a stray light elimination aperture 320 and a field aperture 330 .

The beam selector 310 has at least two aperture diaphragms 311 of adjustable size. In the example shown in FIG1 , the beam selector 310 has two aperture diaphragms 311 arranged vertically, i.e., arranged along the y-axis direction. In addition, the size of the beam selector 310 is comparable to the size of the focusing mirror output spot 101 to improve the utilization efficiency of the beam of the X-ray source. Thus, after the output beam with the focusing mirror output spot 101 is selected by the beam selector 310, it is emitted from the two aperture diaphragms 311 shown in the figure to obtain beams 401 and 402. The beams 401 and 402 will be incident on the irradiated surface of the sample 4 to be tested, and therefore, they are also referred to as incident beams 401 and 402 hereinafter.

A schematic diagram of a beam selector 310 and its variations is shown in Fig. 2. The figure shows a cross-sectional view of the beam selector 310 in the y-axis direction perpendicular to the traveling direction of the X-ray beam.

The beam selector 310 shown on the left side of FIG2 corresponds to the structure shown in FIG1. Due to the presence of the straight light blocker 201, the focusing mirror output light spot 101 is formed into a ring shape as shown in the figure. In the ring region of the focusing mirror output light spot 101, two aperture diaphragms 311 are provided along the up and down directions, and they differ by, for example, 180° along the circumferential direction.

The beam selector 310 shown second on the left side of FIG. 2 is provided with two aperture diaphragms 311 in the annular region of the focusing mirror output light spot 101, which are spaced apart by, for example, 90° along the circumferential direction.

The beam selector 310 shown third on the left side of FIG. 2 is provided with three aperture diaphragms 311 in the annular region of the focusing mirror output light spot 101, which are spaced apart by, for example, 120° along the circumferential direction.

The beam selector 310 shown on the right side of FIG. 2 is provided with four aperture diaphragms 311 in the annular region of the focusing mirror output light spot 101, which are spaced apart by, for example, 90° along the circumferential direction.

The configuration structure of the aperture stop 311 in the beam selector 310 shown here is only an example, and more aperture stops 311 may be configured, for example, more than 5, and may also be configured into a non-rotationally symmetric structure different from that of FIG. 2 , which may be appropriately changed according to actual measurement conditions.

The aperture stop 311 shown here is illustrated as a circular hole, but is not limited to a circular hole structure, and may also be a slit, as long as it is a small hole structure with adjustable size.

Returning to FIG. 1 , the light beams 401 and 402 emitted from the beam selector 310 pass through the stray light elimination aperture 320 respectively, so as to block the stray light of the system.

The field aperture 330 is set at any position within 20 cm in front of the sample 4 to be tested, and is used to adjust the irradiation area size (the position and/or spot size and/or shape and/or convergence or divergence angle of the incident light beams and/or the like) of the two light beams 401 and 402 on the irradiated surface of the sample 4 to be tested. In this embodiment, the irradiation area of the sample 4 to be tested irradiated by the light beams 401 and 402 is substantially the same.

In the present embodiment 1, the divergence angle and spot size of the light beams 401 and 402 can be adjusted by adjusting the aperture size and position of the beam selector 310 (aperture aperture 311), the stray light elimination aperture 320, and the field aperture 330 of the aperture group 3. The divergence angles of the light beams 401 and 402 can be the same or different. Furthermore, the incident angle of the light beams 401 and 402 on the sample to be measured 4 can be adjusted. The incident angle is the angle between the incident light beams 401 and 420 and the wafer normal (i.e., the z-axis) of the sample to be measured 4.

As shown in FIG1 , the light beam 401 irradiates the specified position of the sample 4 to be tested at an incident angle θ1, and the light beam 402 irradiates the specified position of the sample 4 to be tested at an incident angle θ2. θ1 and θ2 are respectively the angles between the light beams 401 and 402 and the normal direction of the irradiated surface of the sample 4 to be tested (as shown by the dotted line in FIG1 , i.e., the z-axis direction), and the relationship of the incident angle θ1≠θ2 holds.

In the first embodiment, the apertures 311 , 320 , and 330 may be slits or pinholes, and the apertures of the apertures may be adjusted independently.

The appropriate incident angle can be selected for irradiation according to the characteristics of different structures (one-dimensional structure, two-dimensional structure, three-dimensional structure) on the sample 4 to be tested. The incident angles of the light beam 401 and the light beam 402 form an angle θ (θ=θ1+θ2). The two X-ray beams 401 and 402 overlap at a specified position of the sample 4 to be tested, and the overlapping spot size is greater than 10 μm.

The sample 4 to be tested may include any suitable microstructure or material, such as single crystal, polycrystalline, amorphous microstructure or any suitable combination thereof, and may also have different microstructures or materials at different positions. In this embodiment, the sample 4 to be tested is a semiconductor wafer, and a high aspect ratio (HAR) structure formed on the surface or inside of the semiconductor wafer using any suitable semiconductor process (such as deposition, photolithography and etching) is provided.

Here, the term "aspect ratio" refers to the arithmetic ratio between the height (depth) and the width (in the case of a circular hole, the diameter of the circular hole) of a given feature formed in the semiconductor wafer of the sample to be tested 4. "High aspect ratio (HAR)" generally refers to an aspect ratio greater than or equal to 10. The HAR structure may include various types of three-dimensional (3D) structures formed in, for example, spin transfer torque random access memory STT-RAM, three-dimensional NAND memory 3D-NAND, dynamic random access memory DRAM, three-dimensional flash memory 3D-FLASH, resistive random access memory Re-RAMPC, and phase change random access memory PC-RAM.

In this embodiment, the characteristic size of the sample 4 to be tested is less than or equal to 200 nm. The sample 4 to be tested has a substrate structure, and its substrate material includes but is not limited to single crystal silicon, gallium arsenide, silicon nitride and indium phosphide. The light intensity transmittance of the two X-ray beams 401 and 402 to the substrate is greater than 0.1.

After the two X-ray beams 401 and 402 are irradiated to the sample 4, they pass through the sample 4 and are scattered by the HAR structure formed on the surface or inside the sample 4. The two X-ray beams 401' and 402' (hereinafter also referred to as detection beams 401' and 402') emitted from the sample 4 are received by the detector 5. The present invention obtains the structural characteristics of the sample by analyzing the scattered X-ray photons.

The detector 5 is, for example, an X-ray array detector, which is used to record the spatial distribution of the light intensity of the scattered light beams 401' and 402', and has a pixel size of less than 150 μm and a total number of pixels greater than 1000×1000, and can simultaneously and completely record the scattered photons generated by the two X-ray beams 401 and 402 scattered on the sample 4 to be tested. Here, the X-ray array detector 5 has the ability to detect a single photon, and its detection efficiency is greater than 0.5. The detector 5 can also be, for example, a charge coupled device (CCD), a CMOS camera, etc.

In addition, by measuring the orientation of the scattering features (e.g., HAR structures) in the sample 4 to be tested relative to the light beams 401 and 402 through the detector 5, the data processing system 6 described later can calculate the orientation of the scattering features relative to the surface of the sample 4 to be tested, which is particularly important for measuring HAR structures (e.g., channel holes in 3D NAND flash memory).

The detector 5 may also be mounted on a rotatable platform (not shown) to improve the sensing efficiency by moving and/or rotating the detector 5. The detector 5 is configured to detect the X-ray beam scattered from the sample 4 to be tested, and includes a sensitive element of sufficiently small size, so that the small-angle scattering intensity distribution of the HAR structure of the sample 4 to be tested can be measured with a desired angular resolution.

The detector 5 is connected to the data processing system 6. The data processing system 6 stores a program for three-dimensional structural reconstruction of the spatial distribution of scattered light intensity collected, so as to process the signals of the two received detection beams 401' and 402' to obtain the three-dimensional structural information of the sample to be tested 4, for example, the horizontal and vertical roughness of the side wall and the spacing change. Regarding the three-dimensional structural reconstruction of the spatial distribution of scattered light intensity, known structural models, goodness of fit GOF parameter numerical analysis, differential evolution DE algorithm, etc. can be used for optimization, including but not limited to Levenberg-Marquardt algorithm (LM), Markov chain Monte Carlo algorithm (Markov chain Monte Carlo, MCMC), genetic algorithm (Genetic Algorithm, GA), differential evolution algorithm (Differential Evolution, DE) and covariance matrix adaptation evolutionary strategy (covariance matrix adaptation evolutionary strategy, CMAES), machine learning or any combination thereof. In addition, parameters can also be extracted by direct analysis, that is, (partial) morphological parameters are extracted according to the position of characteristic peaks in the scattering spectrum, without the need to solve the inverse problem, so as to reduce the size of the inverse problem solution space.

According to the SAXS measurement device 10 of the first embodiment, a large-sized focusing mirror is used to collect X-rays at more angles, and multiple incident light beams are obtained through a beam selector 310 composed of at least two aperture diaphragms, so that the X-rays emitted by the X-ray source have different incident angles at the sample position, and the scattering patterns corresponding to multiple incident angles can be obtained on the detector at the same time. Therefore, the simultaneous detection of information at multiple angles can more effectively utilize the flux of the X-ray source to improve the measurement speed of the sample. At the same time, the introduction of more angle information can effectively improve the measurement accuracy.

The optical elements included in the SAXS measurement device 10 of this embodiment, such as a focusing mirror, various apertures, etc., may be arranged in a vacuum chamber to prevent degradation of one or more optical elements caused by the interaction between air and ionizing radiation on the surface of the optical element.

In this embodiment, the SAXS measurement device 10 also includes a sample stage (not shown) for placing the sample to be tested 4. The sample stage is configured to move the sample to be tested 4 relative to the X-ray beams 401 and 402 in the x-axis and y-axis directions so as to set the desired spatial position of the sample to be tested 4 relative to the incident beam. The sample stage is also configured to move the sample to be tested 4 along the z-axis so as to increase the irradiation of the beams 401 and 402 at the desired position on the surface of the sample to be tested 4 or focus on any other suitable position of the sample to be tested 4. As shown in Figure 1, the sample stage can also rotate around an axis perpendicular to the normal direction of the sample to be tested 4, i.e., the x-axis, for example, it can rotate at least 20°, and the resolution of the rotation angle is less than 5°. Of course, the direction and angle of rotation of the sample to be tested 4 using a rotatable platform are not limited to the situation shown in Figure 1. For example, in the case of using a universal workbench, rotation in any direction and at any angle can also be achieved.

Here, an example is described in which the sample 4 to be measured is moved or rotated while the focusing mirror, aperture group, detector and other optical elements are fixed to perform measurement. However, the sample 4 to be measured may also be fixed and the optical elements may be moved or rotated to perform measurement.

In addition to analyzing and processing the scattered light intensity distribution sensed by the detector 5 to reconstruct the three-dimensional structure of the sample 4 to be measured, the data processing system 6 can also be used as a controller to control various components and assemblies of the measurement device 10. The controller uses an actuator (motor or driver, etc.) to control the position or inclination of the focusing mirror 2, the aperture size and position of each aperture of the aperture group 3, so as to adjust the incident angles θ1, θ2, divergence, spatial shape, intensity and spot size of the two X-ray beams 401 and 402, and is used to block undesired scattered radiation.

<Example 2>

3 is a schematic diagram of a SAXS measuring device 20 according to Embodiment 2 of the present invention. In the SAXS measuring device 20 of Embodiment 2, the incident direction of the X-ray beam 402 is the normal direction of the sample 4 to be measured, that is, the incident angle θ2 of the beam 402 is 0°, so in this case, the incident angle θ of the beams 401 and 402 is θ1. The other structures are the same as those of the SAXS measuring device 10 of Embodiment 1.

Here, the incident light beam 402 is vertically irradiated onto the sample 4 along the normal direction of the sample 4, which is equivalent to a structure of vertical irradiation measurement. On this basis, the second embodiment uses the focusing lens 2 and the aperture group 3 to introduce another beam of X-rays (of course, it can also be multiple beams) with different incident angles, so that scattering diagrams of multiple incident angles can be obtained simultaneously and completely, and the light flux can be used more effectively. At the same time, the introduction of more angle information can effectively improve the measurement accuracy.

The configuration of the SAXS metrology apparatus 10, 20 is shown as an example in order to illustrate certain problems solved by embodiments of the present disclosure and to demonstrate the application of these embodiments in enhancing the performance of such systems. However, embodiments of the present invention are by no means limited to this particular type of example system, and the principles described herein may be similarly applied to other types of X-ray systems for measuring features in any suitable type of electronic device.

<Detection of scattered light intensity distribution of the beam>

FIG4 is a distribution diagram of scattered light intensity of light beams 401′ and 402′ sensed by the detector of the SAXS measuring device 10 of Example 1. In the example of FIG4 , the light beams 401 and 402 after passing through the focusing lens 2 and the aperture group 3 are irradiated onto the sample 4 to be measured, and the sample 4 to be measured includes, for example, a hexagonal array of HAR structures. As shown in FIG4 , since the SAXS measuring device 10 of Example 1 adopts dual-beam incident, and the detector 5 simultaneously detects the scattered light intensity of the two incident light beams after being scattered by the HAR structure in the sample 4 to be measured, the overall image is a ring composed of a plurality of light spots corresponding to different scattered light intensities, wherein the two brightest light spots located on the upper and lower sides (symmetric in FIG4 , corresponding to the structure of the first beam selector 301 shown on the left side of FIG2 ) correspond to the central intensity (for example, the flux of photons and their corresponding energy) of the two light beams 401′ and 402′ sensed by the detector 5. In addition, when the light beams 401 and 402 are each configured to generate coherent scattering at the sample 4 to be tested, the two light spots will be brighter than other places. In the entire annular pattern, as the distance from the two light spots on the left and right sides is increased, the brightness of other light spots gradually dims. The area outside the annular pattern appears black because there is no scattering or the scattering is below the threshold.

FIG5 is a scattered light intensity distribution diagram obtained after the sample 4 to be tested is rotated around the x-axis by a certain angle (for example, 5°) in the SAXS measurement device 10 of Example 1. Similar to the example of FIG4 , the light beams 401 and 402 after passing through the focusing mirror 2 and the aperture group 3 are irradiated onto the sample 4 to be tested, and the sample 4 to be tested includes, for example, a hexagonal array of HAR structures. In FIG5 , the overall image is also a ring composed of a plurality of light spots corresponding to different scattered light intensities. Since the sample 4 to be tested is rotated around the x-axis by, for example, 5°, the annular image of FIG5 is different from the image of FIG4 , and the intensity of the brightest light spots located on the upper and lower sides is reduced relative to that of FIG4 , and the overall width of the annular light spots on both sides is also thinner than that of FIG4 .

FIG6 is a scattered light intensity distribution diagram obtained after the sample 4 to be tested is rotated around the y-axis at different angles (e.g., 5°) in the SAXS measurement device 10 of Example 1. Similar to the examples of FIG4 and FIG5, the light beams 401 and 402 after passing through the focusing mirror 2 and the aperture group 3 are irradiated onto the sample 4 to be tested, and the sample 4 to be tested includes, for example, a hexagonal array of HAR structures. In FIG6, since the sample 4 to be tested is rotated around the y-axis by, for example, 5°, the overall image detected by the detector 5 becomes a semicircle composed of multiple light spots corresponding to different scattered light intensities. The two brightest light spots are no longer located on the upper and lower sides, but are closer to the middle.

FIG7 is a diagram showing the scattered light intensity distribution of the light beams 401' and 402' sensed by the detector of the SAXS measurement device 20 of Example 2. Similar to the example of FIG4 , the light beams 401 and 402 after passing through the focusing mirror 2 and the aperture group 3 are irradiated onto the sample 4 to be tested, and the sample 4 to be tested includes, for example, a hexagonal array of HAR structures, but in Example 2, the incident direction of one of the light beams 402 is the normal direction of the sample 4 to be tested. In FIG5 , the overall image includes a plurality of light spots located in the center and a plurality of light spots located on the lower side. Among them, the light spot located in the center corresponds to the scattered light intensity distribution of the light beam 402 that is vertically incident and scattered, and the light spot located on the lower side corresponds to the scattered light intensity distribution of the other light beam 401.

Here, the detector 5 may adopt a configuration with a total pixel number greater than 1000×1000 and a pixel size less than 150 μm, so as to completely record the scattered photons generated by the two X-ray beams 401 , 402 .

In the above-mentioned embodiments 1 and 2, an example is shown in which the beam selector 310 in the aperture group 3 has two aperture apertures 311 so as to obtain two X-ray beams 401 and 402 to irradiate the sample 4 to be measured. However, the number of aperture apertures 311 of the present invention is not limited to two, but may be three or more, as shown in FIG2 . Therefore, the X-ray beams irradiated to the sample 4 to be measured by the measuring device of the present invention are not limited to two (401, 402), but are changed accordingly according to the setting (number) of the aperture apertures 311, that is, the measuring device of the present invention irradiates multiple X-ray beams to the sample to be measured for measurement.

<Small-angle X-ray scattering (SAXS) measurement method>

Next, the small angle X-ray scattering (SAXS) measurement method of the present invention is described based on Fig. 8. Fig. 8 is a flow chart of the small angle X-ray scattering (SAXS) measurement method of the present invention.

In step S1, the SAXS measurement device 10 (or 20) is initialized, specifically, the X-ray source 1, the focusing mirror 2, the aperture group 3, the sample to be measured 4, and the detector 5 are set to appropriate positions, and initial measurement parameters are set.

In step S2, the positions and sizes of the beam selector 310, the stray light elimination diaphragm 320 and the field of view diaphragm 330 in the diaphragm group 3 are adjusted. For example, the divergence angles of the multiple X-ray light beams 401 and 402 emitted from the diaphragm group 3 are adjusted by adjusting the size of the aperture diaphragm 311 on the beam selector 310; the system stray light is blocked by adjusting the aperture size of the stray light elimination diaphragm 320; and the size of the irradiation area of each of the multiple X-ray light beams 401 and 402 on the sample 4 to be tested is adjusted by adjusting the field of view diaphragm 330.

In step S3, an X-ray array detector 4 is used to completely record the beams 401', 402' of the multiple X-ray beams 401, 402 scattered by, for example, the HAR structure in the sample 4 to be tested, thereby obtaining the spatial distribution of the scattered light intensity.

In step S4, the sample 4 to be tested is rotated, for example, around the x-axis, and step S4 is repeated at different rotation angles to obtain the spatial distribution of scattered light intensity at multiple different rotation angles.

In step S5 , the three-dimensional structure is reconstructed using the spatial distribution of scattered light intensity at multiple different rotation angles obtained in step S5 to obtain the three-dimensional structure information of the sample 4 to be tested, including the HAR structure.

According to the small-angle X-ray scattering measurement device and method based on multi-beam incidence of the present invention, multiple beams of X-rays are obtained by using a focusing mirror and an aperture group and irradiated to the same position of the sample at different incident angles, and the scattering diagrams obtained by the multiple beams of X-rays after being scattered by the sample are simultaneously obtained on the detector, thereby making full use of the flux of the X-ray source to improve the measurement speed of the sample. At the same time, the intensity distribution of scattered light at multiple angles is used to reconstruct the three-dimensional structure, and more information can improve the measurement accuracy.

Although the embodiments described herein primarily deal with X-ray analysis of single-crystal, polycrystalline, or amorphous samples (eg, semiconductor wafers), the methods and apparatus described herein may also be used in other techniques for the application of arrays of nanostructures.

It will therefore be appreciated that the embodiments described above are cited as examples, and that the present invention is not limited to what is particularly shown and described hereinabove. Rather, the scope of the present invention includes combinations and sub-combinations of the various features described hereinabove, as well as variations and modifications thereof that would occur to a person skilled in the art upon reading the above description and that are not disclosed in the prior art. The documents incorporated by reference into this patent application should be considered an integral part of this application, except that to the extent that any term is defined in these incorporated documents in a manner that conflicts with a definition explicitly or implicitly made in this specification, only the definition made in this specification is considered.

Claims (14)

1. A small-angle X-ray scattering measurement device based on multi-beam incidence, used to measure the three-dimensional structural information of a sample, characterized in that it includes: An X-ray source that emits an X-ray beam; A focusing mirror, which focuses the X-ray beam; An aperture group, the aperture group comprising a beam selector having a plurality of aperture apertures, wherein the X-ray beam focused by the focusing mirror passes through the plurality of aperture apertures to selectively obtain a plurality of incident light beams, and the plurality of aperture apertures are respectively used to adjust the divergence angles of the plurality of incident light beams; A sample stage, the sample stage is used to carry the sample, the multiple incident light beams are irradiated to the specified positions on the surface of the sample at different incident angles relative to the normal direction of the sample and overlap; a detector, the detector being arranged on a side of the sample opposite to the X-ray source side, receiving a plurality of detection beams emitted from the sample after the plurality of incident beams are scattered by the sample, so as to obtain a spatial distribution of scattered light intensities of the plurality of detection beams; and A data processing system is provided for determining the three-dimensional structural information of the sample based on the spatial distribution of the scattered light intensity and the incident angles of each of the multiple incident light beams. 2. The small-angle X-ray scattering measurement device according to claim 1, characterized in that: The focal spot divergence angle of the X-ray beam is at least 1 degree. 3. The small-angle X-ray scattering measurement device according to claim 1, characterized in that: The focusing mirror has the function of monochromatic frequency selection. 4. The small-angle X-ray scattering measurement device according to any one of claims 1 to 3, characterized in that: The focal spot position of the focusing mirror is any position from 10 cm in front of the sample to the surface of the detector. 5. The small-angle X-ray scattering measurement device according to any one of claims 1 to 3, characterized in that: The focusing mirror is provided with a direct light blocker for blocking the X-ray beam that directly passes through the focusing mirror. 6. The small-angle X-ray scattering measurement device according to claim 5, characterized in that: Along the incident direction of the X-ray beam, the straight light blocker is arranged at any position between 10 cm in front of the focusing mirror and 10 cm behind the focusing mirror. 7. The small-angle X-ray scattering measurement device according to any one of claims 1 to 3, characterized in that: The aperture group also includes: A field stop for adjusting the size of the irradiation area of the incident light beam irradiating the surface of the sample; and A stray light elimination aperture is arranged between the beam selector and the field of view aperture to eliminate system stray light. 8. The small-angle X-ray scattering measurement device according to any one of claims 1 to 3, characterized in that: The irradiation areas of the multiple incident light beams on the surface of the sample have the same size. 9. The small-angle X-ray scattering measurement device according to any one of claims 1 to 3, characterized in that: The incident directions of the multiple incident light beams have an angle with the normal direction of the sample. 10. The small-angle X-ray scattering measurement device according to any one of claims 1 to 3, characterized in that: The incident direction of one of the multiple incident light beams is the normal direction of the sample. 11. The small-angle X-ray scattering measurement device according to any one of claims 1 to 3, characterized in that: The sample stage is capable of rotating the sample by at least 20 degrees around an axis perpendicular to the normal direction of the sample, and a resolution of the rotation angle is less than 5 degrees. 12. The small-angle X-ray scattering measurement device according to any one of claims 1 to 3, characterized in that: The aspect ratio of the sample is greater than or equal to 10, and the characteristic size is less than or equal to 200nm. 13. A small-angle X-ray scattering measurement method based on multi-beam incidence, using the small-angle X-ray scattering measurement device according to any one of claims 1 to 12 to measure the three-dimensional structure information of a sample, characterized in that it comprises the following steps: Adjusting a plurality of aperture diaphragms provided by the beam selector in the diaphragm group, so that after the X-ray beam emitted by the X-ray source is focused by the focusing lens, it selectively obtains a plurality of incident light beams through the beam selector, and the plurality of incident light beams are irradiated onto a predetermined position on the surface of the sample at different incident angles relative to the normal direction of the sample and overlap, and the plurality of aperture diaphragms are used to adjust the divergence angles of the plurality of incident light beams; Using the detector to receive multiple detection light beams emitted from the sample after the multiple incident light beams are scattered by the sample, and obtaining the scattered light intensity spatial distribution of the multiple detection light beams; and The data processing system determines the three-dimensional structural information of the sample based on the spatial distribution of the scattered light intensity and the information of the incident angles of each of the multiple incident light beams. 14. The small angle X-ray scattering measurement method according to claim 13, further comprising the following steps: The sample stage is adjusted to rotate the sample around an axis perpendicular to the normal direction of the sample, and the detector obtains the scattered light intensity distribution at different rotation angles. The data processing system uses the scattered light intensity distribution at different rotation angles to determine the three-dimensional structural information of the sample.