X-reflection analysis system and x-reflection analysis method utilizing multi-order mode signals

Abstract

本發明公開一種利用多階模態訊號的X反射分析系統及X反射分析方法。X反射分析系統包括X射線產生器、X射線光學元件組、X射線偵測器及處理裝置。X射線產生器產生測量X射線束，X射線光學元件組將測量X射線束引導至待測樣品，X射線偵測器接收測量X射線束照射待測樣品產生的X射線待測訊號。處理裝置收集X射線待測訊號並取出多個模態訊號，針對小於預定階數的模態訊號執行第一擬合分析程序，以產生多個初始參數範圍，並依據初始參數範圍，針對大於或等於預定階數的模態訊號執行第二擬合分析程序，以產生多個參數擬合結果。

Description

[Technical Field]

[0001] This invention relates to an analysis system and analysis method, and in particular to an X-ray reflection analysis system and X-ray reflection analysis method utilizing multi-mode signals. [Previous Technology]

[0002] In existing X-ray measurement systems, when measuring a small area on a sample, the obtained signal is usually very weak, requiring a long integration time to obtain resolvable data. In addition, when the sample size changes slightly, in order to reflect the change and maintain the accuracy of the measurement, it is necessary to obtain measurement results from multiple different angles. As a result, the total accumulated measurement time will be considerable.

[0003] In addition, when the structure of the object to be measured is relatively complex and has many layers, even if a lot of time has been spent to obtain the measurement results, a lot of computing resources and time are required when performing fitting analysis, which affects the measurement efficiency. [Summary of the Invention]

[0004] The technical problem to be solved by the present invention is to provide an X-ray reflection analysis system and X-ray reflection analysis method that utilizes multi-mode signals, in order to overcome the shortcomings of the prior art.

[0005] To solve the above-mentioned technical problems, one of the technical solutions adopted by the present invention is to provide an X-ray reflection analysis system utilizing multi-mode signals, including an X-ray generator, an X-ray optical element assembly, an X-ray detector, and a processing device. The X-ray generator is configured to generate a measurement X-ray beam. The X-ray optical element assembly is used to guide the measurement X-ray beam to the sample to be tested. The X-ray detector is used to receive the X-ray test signal generated by the measurement X-ray beam irradiating the sample to be tested. The processing device is configured to perform the following steps: collecting the X-ray test signal and extracting multiple modal signals of different orders; performing a first fitting analysis procedure for the modal signals whose orders are less than a predetermined order to generate multiple initial parameter ranges corresponding to multiple structural parameters; and performing a second fitting analysis procedure based on the initial parameter ranges for the modal signals whose orders are greater than or equal to the predetermined order to generate multiple parameter fitting results corresponding to the corresponding structural parameters.

[0006] To solve the above-mentioned technical problems, another technical solution adopted by the present invention is to provide an X-ray reflection analysis method using multi-mode signals, comprising: configuring an X-ray generator to generate a measurement X-ray beam; guiding the measurement X-ray beam to the sample to be tested through an X-ray optical element group; receiving the X-ray test signal generated by the measurement X-ray beam irradiating the sample to be tested through an X-ray detector; and configuring a processing device to perform the following steps: collecting the X-ray test signal and extracting multiple modal signals of different orders; performing a first fitting analysis program for the modal signals whose orders are less than a predetermined order to generate multiple initial parameter ranges corresponding to multiple structural parameters; and performing a second fitting analysis program for the modal signals whose orders are greater than or equal to a predetermined order based on the initial parameter ranges to generate multiple parameter fitting results corresponding to the structural parameters.

[0007] One of the beneficial effects of the present invention is that, in the X-ray reflection analysis system and X-ray reflection analysis method using multi-mode signals provided by the present invention, by capturing the sensitivity characteristics of high-order mode signals to subtle changes in three-dimensional structures, the required angle range can be greatly reduced, thus the measurement time can be greatly reduced and the throughput of measurement results can be increased.

[0008] Furthermore, the X-reflection analysis system and X-reflection analysis method using multi-mode signals provided by the present invention also utilize at least two fitting models that have the characteristics of fast calculation and high accuracy, respectively, to significantly reduce the time required for fitting three-dimensional electromagnetic wave models.

[0009] To further understand the features and technical content of the present invention, please refer to the following detailed description and drawings of the present invention. However, the drawings provided are for reference and illustration only and are not intended to limit the present invention.

Implementation Method

[0022] The following specific embodiments illustrate the implementation of the "X-ray reflection analysis system and method utilizing multi-mode signals" disclosed in this invention. Those skilled in the art can understand the advantages and effects of this invention from the content disclosed in this specification. This invention can be implemented or applied through other different specific embodiments, and various details in this specification can also be modified and changed based on different viewpoints and applications without departing from the concept of this invention. Furthermore, the accompanying drawings of this invention are for simple illustrative purposes only and are not depictions of actual dimensions, as stated in advance. The following embodiments will further describe the relevant technical content of this invention in detail, but the disclosed content is not intended to limit the scope of protection of this invention. Additionally, the term "or" used herein should, depending on the actual situation, may include any combination of any one or more of the associated listed items.

[0023] Figure 1 is a schematic diagram of an X-ray analysis system utilizing multi-mode signals according to an embodiment of the present invention. Referring to Figure 1, an embodiment of the present invention provides an X-ray analysis system 1, which includes an X-ray generator 10, an X-ray optical element group 12, an X-ray detector 14, and a processing device 16. The X-ray generator 10 may include an X-ray tube, which contains an electron beam emitter and a target material. The target material is bombarded by an accelerated electron beam to generate a measurement X-ray beam Lx. Furthermore, by selecting different target materials, such as copper (Cu), iron (Fe), molybdenum (Mo), etc., measurement X-ray beams Lx with different energies or different wavelengths (or frequencies) can be generated.

[0024] The X-ray optical element group 12 is used to guide the measurement X-ray beam Lx to the sample SP under test. The sample SP under test may be, for example, a gate-all around and complementary field effect transistor (GAA-FET) structure, or a high aspect ratio three-dimensional NAND flash memory structure that is repeatedly stacked and interconnected in the vertical direction.

[0025] The sample SP to be tested can be placed on a multi-axis sample stage 11, which is, for example, a multi-axis movable stage, such as a three-axis tilting platform or a ball-and-socket tilting platform, for carrying the sample SP to be tested. The multi-axis sample stage 11 may have a stage moving mechanism and a stage rotating mechanism. The stage moving mechanism may include, for example, stepper motors corresponding to the three axes, for moving the sample SP to be tested along one or more of the X-axis, Y-axis, and Z-axis. By controlling the stepper motor of each axis, the sample SP to be tested can be precisely moved to different positions. Taking a ball-and-socket tilting platform as an example, the stage rotating mechanism may be, for example, a ball-and-socket joint connected to the platform, for rotating the sample SP to be tested around one or more of the X-axis, Y-axis, and Z-axis. In detail, the rotation mechanism of the multi-axis sample stage 11 may include controlling the azimuth angle θ of rotation around the Y-axis and the azimuth angle ɸ of rotation around the Z-axis, thereby realizing a full-range scan of the sample SP to be tested.

[0026] The X-ray optical element assembly 12 may include one or more X-ray optical elements. For example, the X-ray optical element assembly 12 may include an X-ray mirror assembly, an X-ray slit, and an X-ray optical collimator sequentially disposed between the X-ray generator 10 and the sample SP to be measured. The X-ray mirror assembly may have a multilayer film structure to focus the measurement X-ray beam Lx horizontally and vertically; the X-ray slit may be used to control the light flux of the measurement X-ray beam Lx incident on the sample SP to be measured, and may also be used to control its vertical divergence angle. The measurement X-ray beam Lx is mainly used for X-ray analysis techniques and may be, for example, a beam with a wavelength range greater than 0.1 nanometers, and may include a hard X-ray beam, a soft X-ray beam, or a gamma-ray beam.

[0027] When the X-ray beam Lx irradiates the sample SP, X-ray signals Lx' will be generated due to reflection, diffraction, scattering, or penetration depending on the incident angle. By placing the X-ray detector 14 at an appropriate position, it can be used to receive the X-ray signals Lx' generated by reflection, diffraction, scattering, or penetration, and generate corresponding X-ray spectrum information. The X-ray detector 14 can be a high spatial resolution detector of one dimension or higher, and can collect signals for X-ray signals Lx' with energies greater than 1 keV. The X-ray detector 14 can also be, for example, a photocoupled device (CCD) or CMOS image sensor in the form of a two-dimensional array, or one or more sensor units (e.g., silicon drift detector (SDD)) can be used to obtain a complete diffraction pattern. In this embodiment of the invention, in order to obtain multi-mode signals, a vertical integration mode can be used to process the received signals on the two-dimensional sensor array signal. The corresponding mode signal is extracted at a specific angular position according to the order, and then subsequent fitting analysis is performed.

[0028] The processing device 16 may be, for example, a computer system including a processor and memory, which may be configured to execute a stored set of instructions or program code to control the X-ray generator 10 to generate a measurement X-ray beam Lx and to perform subsequent analysis on the X-ray signal Lx' received by the X-ray detector 14.

[0029] During the measurement process, the processing device 16 can control the multi-axis sample stage 11 to move and / or rotate so that the X-ray detector 14 can receive multiple X-ray test signals Lx' generated at multiple X-ray measurement angles and generate multiple X-ray spectrum information corresponding to the X-ray test signals Lx'.

[0030] Figure 2 is a cross-sectional schematic diagram of the sample to be tested according to an embodiment of the present invention. Figure 3 is a reflection spectrum diagram of modal signals of different orders obtained under different structural parameters according to an embodiment of the present invention. Figure 4 is a curve diagram of the reflectivity change of modal signals of different orders with respect to different structural parameters according to an embodiment of the present invention. Referring to Figures 2 to 4, the sample to be tested SP may have multiple target structures arranged periodically, and the target structure is, for example, a multilayer element. The target structure has multiple structural parameters, such as one or more of the thickness, linewidth, and roughness of each layer.

[0031] For example, the sample under test SP can be provided with multiple GAA-FETs arranged periodically. As shown in Figure 2, each GAA-FET has multiple silicon germanium (SiGe) layers T1 and silicon layers T2 stacked on each other, and silicon nitride layer T3 and silicon dioxide layer T4 are arranged on top in sequence. Generally speaking, the size of the silicon germanium (SiGe) layer in the X and Y directions is regarded as the critical dimension (CD), which is a key indicator that determines the power and performance characteristics of the GAA-FET device.

[0032] In this embodiment, the length of the silicon-germanium (SiGe) layer in the X and Y directions is referred to as the linewidth. The zero-order modal signal, first-order modal signal, and second-order modal signal obtained at different linewidths (110 Å, 120 Å, and 130 Å) are shown in Figure 3, and the signal changes with linewidth variation are shown in Figure 4. As can be seen from Figures 3 and 4, within a specific angle range, higher-order modal signals (first-order and second-order modal signals) exhibit more drastic reflectivity changes compared to lower-order modal signals (zero-order modal signals) under the same linewidth variation. In other words, higher-order modal signals (first-order and second-order modal signals) are highly sensitive to linewidth at specific angles. Based on this phenomenon, the higher-order modal signals of different orders measured within a specific angle range can be considered as important information for fitting analysis, thereby obtaining the key dimensions (i.e., the structural parameters of the sample SP to be tested). It should be noted that although the zero-order mode signal has low sensitivity, it is still of reference value when used to roughly estimate the range of structural parameters.

[0033] Based on the above analysis, this embodiment of the invention also provides an X-ray reflection analysis method utilizing multi-mode signals. Please refer to Figure 5, which is a flowchart of the X-ray reflection analysis method utilizing multi-mode signals according to an embodiment of the invention. The X-ray reflection analysis method includes at least the following steps:

[0034] Step S10: Configure the X-ray generator to generate a measurement X-ray beam.

[0035] Step S11: Guide the measuring X-ray beam to the sample to be tested through the X-ray optical element group.

[0036] Step S12: Receive the X-ray signal generated by the X-ray beam irradiating the sample under test through the X-ray detector.

[0037] The X-ray reflection analysis method also includes configuring the processing device 16 to perform the following steps:

[0038] Step S13: Collect the X-ray signal to be tested and extract multiple modal signals of different orders.

[0039] Please refer to Figure 6, which is a detailed flowchart of step S13. As shown in Figure 6, step S13 includes:

[0040] Step S130: Obtain multiple diffraction patterns within a predetermined angle range using an X-ray detector.

[0041] Step S131: For each diffraction pattern, extract multiple intensity signals corresponding to different orders. Please refer to Figure 7, which is a schematic diagram of the diffraction pattern generated after the test pattern reflects the measured X-ray beam according to an embodiment of the present invention. For example, the axis region with the strongest light intensity can be found in the diffraction pattern (as shown by the dashed line in Figure 7), and the light intensity data can be fitted using the Lorentzian function to separate the modal signals of each order.

[0042] Step S132: Integrate the intensity signals of the same order within a predetermined angle range, and calculate multiple reflection spectra corresponding to different orders as the modal signals.

[0043] Please refer to Figure 8, which is a graph of the separated modal signals of each order according to an embodiment of the present invention. In this step, after obtaining the modal signal of each order, the modal signals of different angles can be further integrated to generate data on the change of reflected light intensity with angle. Then, the reflectivity at different angles can be calculated based on the value of the reflected light intensity, as shown in Figure 8.

[0044] Step S14: Perform a first fitting analysis procedure for the modal signals whose order is less than a predetermined order to generate multiple initial parameter ranges corresponding to multiple structural parameters.

[0045] In step S14, the first fitting analysis procedure includes fitting modal signals of order less than a predetermined order to the target structure of the sample SP under test using an Effective medium approximation (EMA) model, to generate multiple initial parameter ranges corresponding to the corresponding structural parameters. In this embodiment, the predetermined order can be obtained based on the modal signals with low sensitivity obtained from the aforementioned analysis (e.g., zero-order modal signals), therefore the predetermined order is first order, and modal signals of order less than first order can be used in step S14 to quickly estimate the parameter range of the structural parameters.

[0046] It should be noted that the effective medium approximation model is an analytical or theoretical model used to describe the macroscopic properties of composite materials. This theory calculates the properties of the composite material by averaging the properties of each component in the composite material. Since the parameters of each component constituting the composite material are different and often non-uniform, it is almost impossible to calculate completely accurately. Therefore, the effective medium approximation theory treats the composite material as a whole and approximates its parameters and properties. Figure 9 is a schematic diagram of fitting the EMA model in an embodiment of the present invention. Referring to Figure 9, when fitting the target structure with the EMA model, the target structure is equivalent to a stacked structure with multiple material layers, and the characteristics of each layer are described by the volume and density of each layer. For example, when the size of the silicon-germanium layer is smaller than that of the silicon layer below, the silicon-germanium layer and the air portion on both sides are equivalent to a virtual layer L2, and the density of the virtual layer L2 is obtained by the following formulas (1) and (2):

[0047] Equation (1);

[0048] Equation (2);

[0049] where is the density of virtual layer L2, is the density of silicon-germanium layer, is the volume of silicon-germanium layer, is the density of air portion, is the volume of air portion, is the total volume of virtual layer L2, and , are the length, width, and height of virtual layer L2, respectively.

[0050] Therefore, the aforementioned stacked structure with multiple material layers is a guessing model used to fit the zero-order modal signal. Its purpose is to use the zero-order modal signal as the fitting target, and by guessing the initial parameter range of key dimensions such as the length and width (i.e., linewidth) of the silicon-germanium layer, the initial parameter range at which the fitting completion condition is met (e.g., determining whether convergence) is used as the fitting result. In addition, structural parameters may also include key dimensions such as thickness and roughness.

[0051] Step S15: Based on the initial parameter range, execute a second fitting analysis program for the modal signals whose order is greater than a predetermined order, so as to generate multiple parameter fitting results corresponding to the structural parameters.

[0052] Please refer to Figure 10, which is a detailed flowchart of step S15. In step S15, the second fitting analysis procedure includes the following steps:

[0053] Step S150: Input the modal signals whose order is greater than or equal to a predetermined order into a three-dimensional electromagnetic wave optimization model. In this step, the predetermined order can be, for example, first order. Therefore, high-order modal signals that are highly sensitive to linewidth variations, including first-order modal signals and second-order modal signals, can be input into the three-dimensional electromagnetic wave optimization model.

[0054] In some embodiments, the three-dimensional electromagnetic wave optimization model may include, for example, one or more of the following algorithms: Finite-Difference Time-Domain (FDTD), Distorted Wave Born Approximation (DWBA), Rigorous Coupled Wave Analysis (RCWA), Discrete Dipole Approximation (DDP), and Boundary Element Method (BEM).

[0055] Step S151: Using the initial parameter range and the target structure of the sample to be tested as initial fitting conditions, fit the modal signals whose order is greater than a predetermined order to generate the parameter fitting results corresponding to the structural parameters respectively.

[0056] For example, the initial parameter range can be used as the initial fitting condition of the three-dimensional electromagnetic wave optimization model by means of the transfer matrix method, and the first-order modal signal and the second-order modal signal can be used as fitting targets respectively to generate parameter fitting results corresponding to multiple structural parameters (such as line width, thickness and / or roughness) under the premise of reaching the convergence condition.

[0057] It should also be noted that the present invention can also determine the specific angle for obtaining each modal signal. Please refer to Figure 11, which is a flowchart of the pre-simulation procedure of an embodiment of the present invention. In some embodiments, the predetermined angle range can be obtained through the pre-simulation procedure, which includes the following steps:

[0058] Step S20: Adjust one or more of the structural parameters of the target structure.

[0059] For example, the line width, thickness and roughness can be adjusted separately, and the angle range with higher sensitivity to each modal signal can be found.

[0060] Step S21: Simulate and generate multiple simulated modal signals of different orders generated at multiple simulated angles after the adjusted target structure is irradiated by X-rays.

[0061] In this step, the simulated modal signals can be obtained by optical simulation based on the adjusted structural parameters.

[0062] Step S22: Obtain the sensitive angle range that is highly sensitive to changes in these structural parameters based on the simulated modal signal as the predetermined angle range.

[0063] Specifically, reflection spectrum diagrams of modal signals of different orders under different structural parameters, similar to those in Figure 3, can be obtained, and the sensitive angle ranges with significantly different sensitivities of each modal signal can be identified, which can be used as a predetermined angle range for fitting analysis of specific structural parameters.

[0064] Furthermore, for simpler three-dimensional structural dimension changes, the intensities of modal signals of multiple orders can be compared, and the corresponding structural changes can be identified based on the comparison results. For example, within an appropriate sensitive angle range, a lookup table can be established, defining the relationship between the relative intensity of each modal signal and a specific linewidth change, which may be linear or nonlinear. Using this relationship, when performing measurements within this sensitive angle range, only the intensity of each modal signal needs to be detected to find the linewidth change, thereby reducing the overall measurement time.

[0065] Referring to Figure 12, which is a graph of the signal strength ratio versus linewidth in an embodiment of the present invention. The relative intensity relationship between each order of modal signals can be defined by recording the signal strength ratios at multiple different linewidths (e.g., zeroth order to first order and zeroth order to second order). Then, the linewidth change can be directly determined based on the intensity of the separated signals without the need for calculation through fitting analysis, thus significantly improving the overall measurement speed.

[0066] [Beneficial Effects of the Embodiments]

[0067] One of the beneficial effects of the present invention is that, in the X-ray reflection analysis system and X-ray reflection analysis method using multi-mode signals provided by the present invention, by capturing the sensitivity characteristics of high-order mode signals to subtle changes in three-dimensional structures, the required angle range can be greatly reduced, thus the measurement time can be greatly reduced and the throughput of measurement results can be increased.

[0068] Furthermore, the X-reflection analysis system and X-reflection analysis method using multi-mode signals provided by the present invention also utilize at least two fitting models that have the characteristics of fast calculation and high accuracy, respectively, to significantly reduce the time required for three-dimensional electromagnetic wave fitting models.

[0069] The content disclosed above is only a preferred and feasible embodiment of the present invention, and is not intended to limit the scope of the patent application of the present invention. Therefore, all equivalent technical changes made using the contents of the present invention specification and drawings are included in the scope of the patent application of the present invention. [Simplified Explanation of the Diagram]

[0010] Figure 1 is a schematic diagram of an X-ray analysis system utilizing multi-mode signals according to an embodiment of the present invention.

[0011] Figure 2 is a cross-sectional schematic diagram of the sample to be tested according to an embodiment of the present invention.

[0012] Figure 3 is a reflection spectrum diagram of modal signals of different orders obtained under different structural parameters according to the embodiment of the present invention.

[0013] Figure 4 is a graph showing the reflectivity changes of different orders of modal signals for different structural parameters according to an embodiment of the present invention.

[0014] Figure 5 is a flowchart of the X-ray analysis method using multi-mode signals according to an embodiment of the present invention.

[0015] Figure 6 is a detailed flowchart of step S13.

[0016] Figure 7 is a schematic diagram of the diffraction pattern generated after the test pattern reflects the X-ray beam in an embodiment of the present invention.

[0017] Figure 8 is a graph of the separated modal signals according to an embodiment of the present invention.

[0018] Figure 9 is a schematic diagram of fitting using the EMA model in an embodiment of the present invention.

[0019] Figure 10 is a detailed flowchart of step S15.

[0020] Figure 11 is a flowchart of the pre-simulation program of an embodiment of the present invention.

[0021] Figure 12 is a curve of signal strength to line width according to an embodiment of the present invention.

Claims

1. An X-ray reflection analysis system utilizing multi-modal signals, comprising: An X-ray generator configured to generate a measurement X-ray beam; an X-ray optical element assembly for guiding the measurement X-ray beam to a sample under test; an X-ray detector for receiving an X-ray signal under test generated by the measurement X-ray beam irradiating the sample under test within a predetermined angle range; and a processing device configured to perform the following steps: collecting the X-ray signal under test and extracting multiple modal signals of different orders; performing a first fitting analysis procedure for the modal signals whose orders are less than a predetermined order to generate multiple initial parameter ranges corresponding to multiple structural parameters; and performing a second fitting analysis procedure based on the initial parameter ranges for the modal signals whose orders are greater than or equal to a predetermined order to generate multiple parameter fitting results corresponding to the structural parameters, wherein the predetermined angle range is obtained by the processing device performing a pre-simulation procedure, the pre-simulation procedure including: adjusting one or more of the structural parameters of a target structure of the sample under test. The simulation generates multiple simulated modal signals of different orders at multiple simulated angles after the adjusted target structure is irradiated by X-rays; and a sensitive angle range with high sensitivity to changes in the structural parameters is obtained based on the simulated modal signals as the predetermined angle range.

2. The X-ray reflection analysis system as described in claim 1, wherein, The steps of collecting the X-ray signal to be tested and extracting multiple modal signals of different orders include: obtaining multiple diffraction patterns within the predetermined angle range using the X-ray detector; extracting multiple intensity signals of different orders for each diffraction pattern; and integrating the intensity signals of the same order within the predetermined angle range and calculating multiple reflection spectra of different orders as the modal signals.

3. The X-ray reflection analysis system as described in claim 2, wherein, The first fitting analysis procedure includes fitting the modal signals to the target structure of the sample under test using an Effective Medium Approximation (EMA) model to generate the initial parameter ranges corresponding to the structural parameters, respectively.

4. The X-ray reflection analysis system as described in claim 3, wherein, When the EMA model is fitted to the target structure, the target structure is equivalent to a single-layer structure with multiple material layers.

5. The X-ray reflection analysis system as described in claim 2, wherein, The second fitting analysis procedure includes inputting the modal signals whose order is greater than the predetermined order into a three-dimensional electromagnetic wave optimization model, using the initial parameter range and a target structure of the sample under test as an initial fitting condition, fitting the modal signals whose order is greater than the predetermined order to generate the parameter fitting results corresponding to the structural parameters respectively.

6. The X-ray reflection analysis system as described in claim 1, wherein, The target structure of the sample to be tested is a multilayer element, and the structural parameters include one or more of the thickness, linewidth and roughness of each layer.

7. An X-ray reflection analysis method utilizing multi-mode signals, comprising: Configure an X-ray generator to produce a measuring X-ray beam; The X-ray beam is guided to a sample under test by an X-ray optical element assembly; an X-ray detector receives an X-ray signal under test generated by the X-ray beam irradiating the sample under test within a predetermined angle range; and a processing device is configured to perform the following steps: collecting the X-ray signal under test and extracting multiple modal signals of different orders; performing a first fitting analysis program for the modal signals whose orders are less than a predetermined order to generate multiple initial parameter ranges corresponding to multiple structural parameters; and performing a second fitting analysis program for the modal signals whose orders are greater than a predetermined order based on the initial parameter ranges to generate multiple parameter fitting results corresponding to the structural parameters, wherein the predetermined angle range is obtained by performing a pre-simulation program by the processing device, the pre-simulation program including: adjusting one or more of the structural parameters of the target structure. The simulation generates multiple simulated modal signals of different orders at multiple simulated angles after the adjusted target structure is irradiated by X-rays; and a sensitive angle range with high sensitivity to changes in the structural parameters is obtained based on the simulated modal signals as the predetermined angle range.

8. The X-ray reflection analysis method as described in claim 7, wherein, The steps of collecting the X-ray signal to be tested and extracting multiple modal signals of different orders include: obtaining multiple diffraction patterns within the predetermined angle range using the X-ray detector; extracting multiple intensity signals of different orders for each diffraction pattern; and integrating the intensity signals of the same order within the predetermined angle range and calculating multiple reflection spectra of different orders as the modal signals.

9. The X-ray reflection analysis method as described in claim 8, wherein, The first fitting analysis procedure includes fitting the modal signals to the target structure of the sample under test using an Effective Medium Approximation (EMA) model to generate the initial parameter ranges corresponding to the structural parameters, respectively.

10. The X-ray reflection analysis method as described in claim 9, wherein, When the EMA model is fitted to the target structure, the target structure is equivalent to a single-layer structure with multiple material layers.

11. The X-ray reflection analysis method as described in claim 10, wherein, The second fitting analysis procedure includes inputting the modal signals whose order is greater than the predetermined order into a three-dimensional electromagnetic wave optimization model, using the initial parameter range and a target structure of the sample under test as an initial fitting condition, fitting the modal signals whose order is greater than the predetermined order to generate the parameter fitting results corresponding to the structural parameters respectively.

12. The X-ray reflection analysis method as described in claim 7, wherein, The target structure of the sample to be tested is a multilayer element, and the structural parameters include one or more of the thickness, linewidth and roughness of each layer.

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