Single crystal semiconductor wafer measurement system and method

Abstract

The application discloses a single-crystal semiconductor wafer measurement system and method, the system comprises a first light source system, a multi-degree-of-freedom positioning platform, a first detection system, the first light source system emits first X-rays to irradiate a measurement point of a sample on the multi-degree-of-freedom positioning platform, and the first detection system detects a scattering image formed by the first X-rays passing through the sample, and the system further comprises: a second light source system, which is used for emitting second X-rays from multiple angles, and the focal points of the second X-rays of the multiple angles coincide with the measurement point on the sample; a second detection system, which is used for receiving diffraction X-rays formed by the second X-rays irradiating the sample, and identifying the landing position of the diffraction X-rays; and a calculation module, which is used for analyzing the landing position based on the Bragg diffraction principle to obtain the direction information of the plane where the measurement point is located. When CD-SAXS measurement is performed, the measurement of the direction of the plane where the wafer measurement point is located is simultaneously performed, and the efficiency is higher.

Description

Technical Field

[0001] This application relates to the field of key dimension measurement technology for nanogratings or nanofield-effect transistors, and in particular to a single-crystal semiconductor wafer measurement system and method. Background Technology

[0002] With the development of semiconductor manufacturing technology, the linewidth of etched structures in semiconductor devices is becoming smaller and the etching depth is becoming larger, thus forming unique high aspect ratio (HAR) structures. Etching of high aspect ratio structures is a critical and challenging process step in semiconductor device manufacturing, significantly impacting device performance and yield. For example, in the manufacturing process of modern 3D NAND memory devices, with the continuous vertical scaling of 3D-NAND structures, the aspect ratio of memory hole structures in the most advanced manufacturing processes currently available is greater than 50:1 (the aspect ratio is the ratio of height to diameter). Therefore, accurately characterizing the etching process and quality during semiconductor device development and monitoring it during manufacturing are becoming increasingly difficult, but also increasingly important.

[0003] Small-angle X-ray scattering (SAXS) is an X-ray metrology technique used to measure structural features on the 1-100 nanometer scale, with the potential to measure complex periodic nanostructures (such as the high aspect ratio etched structures of FinFETs and 3D NAND cells). Critical dimension small-angle X-ray scattering (CD-SAXS) is a transmission-based, variable-angle SAXS measurement technique and a non-destructive measurement method. Due to the short wavelength and deep penetration of high-energy X-rays, CD-SAXS utilizes the scattering of X-rays by periodic nanomaterials to simultaneously measure critical dimensions in both the lateral and depth directions of the HAR structure of semiconductor devices. Furthermore, as the number of stacked layers in semiconductor devices (such as 3D NAND) increases, the CD-SAXS measurement signal intensity increases accordingly, further enhancing the measurement capability—a feature not possessed by other measurement methods (such as optical measurement methods like OCD). Therefore, CD-SAXS has unique advantages for the precise measurement of HAR structures.

[0004] In CD-SAXS, a high-energy X-ray beam passes through a semiconductor wafer and is scattered from a periodic nanostructure. The angular distribution of the scattered intensity is measured by a two-dimensional array detector. The wafer is then deflected so that the crystal plane normal forms a series of different angles with the incident beam, allowing the X-ray beam to pass through the sample at a series of different incident angles. Scattering images at these different incident angles are captured to determine the angular dependence of the scattering mode. Therefore, for CD-SAXS equipment, the wafer sample under test can only be placed on a perforated sample stage so that the stage does not obstruct the X-rays scattered by the HAR structure from being received by the CD-SAXS detection equipment. The wafer sample can only be fixed by edge clamping. Figure 1 As shown. Although this clamping method ensures that every point on the wafer under test can be measured, the uneven force on the wafer caused by its hollow structure and edge clamping inevitably leads to changes in the wafer's surface shape, such as bending and warping. Therefore, the surface orientation of each local area on the wafer under test varies. Since the CD-SAXS measurement signal is highly angle-dependent, the accuracy of measuring the angular relationship between the scattered signal and the sample surface orientation directly determines the accuracy of the CD-SAXS equipment in measuring the critical dimensions of the semiconductor wafer's nano-etched structure. Therefore, in addition to measuring the X-ray scattering signal of the nano-etched structure of the wafer under test, measuring the surface orientation at the measurement point on the wafer is also crucial in CD-SAXS equipment.

[0005] Currently, there are three main methods used in the CD-SAXS metrology system to determine the planar orientation at the measurement point of a wafer:

[0006] The first method utilizes an optical distance sensor to measure the perpendicular distances of three points near the measurement point relative to the optical sensor. The plane defined by these three points approximates the plane at the measurement point. Then, the direction of the plane defined by the three points is calculated geometrically based on the changes in their perpendicular distances relative to the optical sensor; this direction is considered the sample surface orientation at the measurement point. However, this method has limitations: firstly, the accuracy of the surface orientation at the wafer measurement point is highly dependent on the selection of the optical sensor's measurement point position, and is also affected by the parallelism of the moving platform's axis and vibrations during the measurement of the three points; secondly, because measuring three points requires moving the wafer or the optical distance sensor, it is impossible to measure the surface orientation at the wafer measurement point simultaneously with CD-SAXS measurement, which significantly increases the overall measurement time and greatly reduces the measurement throughput of the CD-SAXS measurement equipment.

[0007] The second method for determining the surface orientation at a measurement point on a wafer utilizes the principle of optical reflection. It calculates the surface orientation based on the position of the reflected laser beam on the optical detector at the measurement point. However, because this method relies on the reflection of the laser beam from the sample surface, it is highly susceptible to the surface morphology (such as surface roughness and etching patterns), which significantly impacts the determination of the sample surface orientation at the measurement point.

[0008] The third method involves using X-ray diffraction to determine the crystal orientation. This method uses beam X-rays, a goniometer to scan the angles, and then determines the crystal orientation based on the rocking curve. While these methods can accurately determine the surface orientation of the sample, the measurement time is very long due to the need for angle scanning. Summary of the Invention

[0009] In view of this, this application provides a single-crystal semiconductor wafer measurement system and method to solve the problem of low efficiency in existing single-crystal semiconductor wafer measurement methods.

[0010] To solve the above-mentioned technical problems, one technical solution adopted in this application is: providing a single-crystal semiconductor wafer measurement system, which includes a first light source system, a multi-degree-of-freedom positioning platform, and a first detection system arranged sequentially. The first light source system emits first X-rays that irradiate the measurement point of the sample on the multi-degree-of-freedom positioning platform, and the first detection system detects the scattered image formed by the first X-rays passing through the sample. The system further includes: a second light source system, whose relative spatial position to the optical path formed by the first X-rays is preset, for emitting second X-rays from multiple angles, and the focal points of the second X-rays from multiple angles coincide with the measurement point on the sample; a second detection system, whose relative spatial position to the optical path formed by the first X-rays is preset, for receiving the diffracted X-rays formed by the second X-rays irradiating the sample, and identifying the landing point position of the diffracted X-rays; and a calculation module, electrically connected to the second detection system, for analyzing the landing point position based on the Bragg diffraction principle to obtain the orientation information of the plane where the measurement point is located.

[0011] As a further improvement of this application, the second light source system emits a cone-shaped X-ray beam, and the focal point of the cone-shaped X-ray beam coincides with the measurement point on the sample.

[0012] As a further improvement of this application, the second detection system includes a two-dimensional array X-ray detector, which includes multiple pixels, and the line connecting each pixel and the measurement point forms a specific angle with the optical path formed by the first X-ray.

[0013] As a further improvement of this application, the calculation module is used to determine the target pixel point of the diffracted X-ray based on the landing position of the diffracted X-ray, and calculate the diffraction angle of the diffracted X-ray based on Bragg's law of diffraction, and then calculate the angle between the normal of the plane where the measurement point is located and the light path based on the diffraction angle and the target specific angle corresponding to the target pixel point.

[0014] As a further improvement to this application, the calculation process for the included angle is expressed as follows:

[0015]

[0016] Where β represents the angle between the normal to the plane where the measurement point is located and the optical path, and θ represents the diffraction angle. This represents the specific angle between the line connecting the target pixel and the measurement point and the optical path.

[0017] As a further improvement of this application, it also includes a vacuum collimation system, which is disposed between the first light source system and the multi-degree-of-freedom positioning platform. The vacuum collimation system is provided with a first slit, a second slit and a third slit in sequence. The first slit and the second slit are in a vacuum environment. The light path formed by the first X-ray passes through the first slit, the second slit and the third slit in sequence to irradiate the sample.

[0018] As a further improvement of this application, it also includes a vacuum scattering system, which is disposed between the multi-degree-of-freedom positioning platform and the first detection system. The vacuum scattering system includes a high-vacuum cavity for transmitting the scattered image to the first detection system.

[0019] To solve the above-mentioned technical problems, another technical solution adopted in this application is: providing a single-crystal semiconductor wafer measurement method, which is applied to one of the single-crystal semiconductor wafer measurement systems mentioned above; the method includes: S1, controlling the rotation of a multi-degree-of-freedom positioning platform so that the sample is at a preset angle; S2, controlling the first light source system and the second light source system to start working, the first light source system emitting first X-rays and the second light source system emitting second X-rays at multiple angles irradiating the measurement point of the sample; S3, using a first detector to collect the scattering image formed by the measurement point of the sample under the first X-ray irradiation, and simultaneously controlling the second detector to collect the diffracted X-rays formed by the measurement point of the sample under the second X-ray irradiation, and identifying the landing position of the diffracted X-rays; S4, using a calculation module to analyze the landing position based on the Bragg diffraction principle to obtain the orientation information of the plane where the measurement point is located; controlling the multi-degree-of-freedom positioning platform to rotate to different preset angles, and repeating steps S2 to S4 until the measurement is completed.

[0020] As a further improvement of this application, the second detection system includes a two-dimensional array X-ray detector, which includes multiple pixels. The line connecting each pixel and the measurement point forms a specific angle with the optical path formed by the first X-ray. The calculation module analyzes the landing point position based on the Bragg diffraction principle to obtain the orientation information of the plane where the measurement point is located. This includes: the calculation module confirming the target pixel of the diffracted X-ray landing point based on the landing point position of the diffracted X-ray; the calculation module calculating the diffraction angle of the diffracted X-ray based on the Bragg diffraction law; and the calculation module calculating the angle between the normal of the plane where the measurement point is located and the optical path based on the diffraction angle and the specific angle corresponding to the target pixel.

[0021] As a further improvement to this application, the calculation process for the included angle is expressed as follows:

[0022]

[0023] Where β represents the angle between the normal to the plane where the measurement point is located and the optical path, and θ represents the diffraction angle. This represents the specific angle between the line connecting the target pixel and the measurement point and the optical path.

[0024] The beneficial effects of this application are as follows: The single-crystal semiconductor wafer measurement system of this application utilizes the strong penetrating properties of X-rays and the Bragg diffraction effect of the single-crystal silicon substrate. The X-ray beam emitted by the second light source system contains multiple rays with different incident angles. Only the ray beam whose incident angle meets the Bragg diffraction conditions of the single-crystal silicon substrate can pass through the diffraction of the single-crystal silicon substrate and be received by the second detection system. The diffraction direction of the diffracted X-rays can be calculated based on the landing position of the diffracted X-rays in the second detection system. Thus, the crystal plane orientation at the measurement point can be calculated based on the angle relationship of Bragg diffraction. This allows CD-SAXS measurement and measurement of the crystal plane orientation of the sample at the measurement point to be performed simultaneously without the need for a fine angle scanning process, which greatly reduces the measurement time and improves the measurement efficiency. Moreover, it is not affected by the surface morphology of the sample (such as surface roughness, etching patterns, etc.), resulting in higher accuracy of the measurement results. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the sample fixation method in existing small-angle X-ray scattering measurement equipment;

[0026] Figure 2 This is a schematic diagram of the single-crystal semiconductor wafer measurement system according to an embodiment of the present invention;

[0027] Figure 3 This is a schematic diagram of the optical path structure in the single-crystal semiconductor wafer measurement system of this invention, where the crystal plane normal of the sample is parallel to the optical path axis;

[0028] Figure 4 This is a schematic diagram of the optical path structure in the single-crystal semiconductor wafer measurement system of the present invention, when the crystal plane normal of the sample is deflected by a negative angle relative to the optical path axis.

[0029] Figure 5 This is a schematic diagram of the optical path structure in the single-crystal semiconductor wafer measurement system of the present invention, when the crystal plane normal of the sample is deflected by a positive angle relative to the optical path axis.

[0030] Figure 6 This is a schematic diagram illustrating the calculation of the angle between the plane where the measurement point is located and the optical path in the single-crystal semiconductor wafer measurement system according to an embodiment of the present invention;

[0031] Figure 7 This is a schematic flowchart of a single-crystal semiconductor wafer measurement method according to an embodiment of the present invention. Detailed Implementation

[0032] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0033] The terms "first," "second," and "third" in this application are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first," "second," or "third" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. All directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative spatial positions and movements of components in a specific orientation (as shown in the figures). If the specific orientation changes, the directional indications also change accordingly. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or devices.

[0034] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0035] Figure 2 This is a schematic diagram of the structure of a single-crystal semiconductor wafer measurement system according to an embodiment of the present invention. Figure 2 As shown, the single-crystal semiconductor wafer measurement system includes: a first light source system 1, a multi-degree-of-freedom positioning platform 2, a first detection system 3, a second light source system 4, a second detection system 5, and a computing module (not shown in the figure). The first light source system 1, the multi-degree-of-freedom positioning platform 2, and the first detection system 3 are arranged sequentially.

[0036] The first light source system 1 includes an X-ray source and a collimating monochromator. The X-ray source is used to generate a point-divergent X-ray beam. The collimating monochromator converts the point-divergent polychromatic X-ray beam generated by the X-ray source into a quasi-monochromatic quasi-parallel X-ray beam, i.e., the first X-ray.

[0037] The multi-degree-of-freedom positioning platform 2 is used to achieve precise positioning of any point on the sample (i.e., it includes high-precision XYZ motion axes), so that the optical path formed by the first X-ray can accurately irradiate the measurement point on the sample. At the same time, it can realize the angle deflection scanning control of the sample relative to the optical path axis, so that the first X-ray is projected through the sample at a series of different incident angles, forming a series of scattering images with different incident angles.

[0038] The first detection system 3 is used to detect the scattering image formed by the first X-ray passing through the sample, in order to determine the angle dependence of the scattering mode.

[0039] The relative spatial position of the second light source system 4 and the light path formed by the first X-ray is preset to emit second X-rays from multiple angles, and the focal point of the second X-rays from multiple angles coincides with the measurement point on the sample.

[0040] The relative spatial position of the second detection system 5 and the optical path formed by the first X-ray is preset, which is used to receive the diffracted X-rays formed by the second X-ray irradiating the sample and identify the landing point of the diffracted X-rays.

[0041] It is important to understand that in this embodiment, the relative spatial positions between the second light source system 4, the second detection system 5, and the optical path formed by the first X-ray are preset. Furthermore, the focal point of the multiple angles of the second X-rays emitted by the second light source system 4 is located at the measurement point of the sample on the multi-degree-of-freedom positioning platform 2; that is, this focal point coincides with the point on the sample where the first X-ray irradiates. For multiple measurement points on the sample, after measuring one point, the sample is moved using the multi-degree-of-freedom positioning platform 2 so that the next measurement point is located at the position where the first X-ray optical path penetrates the sample, which is also the focal point of the second X-ray.

[0042] The calculation module is electrically connected to the second detection system 5 and is used to analyze the landing point position to obtain the orientation information of the plane where the measurement point is located.

[0043] It should be noted that the single-crystal semiconductor wafer measurement system of this embodiment is used to measure single-crystal semiconductor wafers with a clearly defined single-crystal structure and composition. For single-crystal samples, when irradiated with X-rays, only X-rays whose incident angle satisfies the Bragg diffraction principle can be diffracted by the single-crystal silicon of the sample substrate. Other X-rays that do not conform to the Bragg diffraction principle will not produce diffraction phenomena. Therefore, it is not necessary to adjust the incident angle of the second X-ray emitted by the second light source system 4, and it is not necessary to perform fine angle scanning control to measure the crystal plane direction of the measurement point of the sample. It is not affected by the surface morphology of the sample (such as surface roughness, etching patterns, etc.).

[0044] Specifically, please refer to Figure 3 , Figure 4 and Figure 5 As shown, Figure 3 This is a schematic diagram of the optical path structure when the crystal plane normal of the sample is parallel to the optical path axis. Figure 4 This is a schematic diagram of the optical path structure when the normal of the crystal plane of the sample is deflected by a negative angle relative to the optical path axis. Figure 5 This is a schematic diagram of the optical path structure when the normal of the sample's crystal plane is deflected by a positive angle relative to the optical path axis. The process of measuring the sample by this single-crystal semiconductor wafer measurement system is as follows: First, the multi-degree-of-freedom positioning platform 2 is controlled to rotate so that the sample is at a preset angle (e.g., Figure 3(As shown); then, the first light source system 1 and the second light source system 4 are controlled to start working. The first light source system 1 emits first X-rays, and the second light source system 4 emits second X-rays at multiple angles, all of which irradiate the measurement point of the sample. Then, the first detector is used to collect the scattering image formed by the measurement point of the sample under the first X-ray irradiation, and at the same time, the second detector is controlled to collect the diffracted X-rays formed by the measurement point of the sample under the second X-ray irradiation, and the landing position of the diffracted X-rays is identified. Finally, the landing position is analyzed using the calculation module to obtain the orientation information of the plane where the measurement point is located. By controlling the multi-degree-of-freedom positioning platform 2 to rotate to different preset angles (such as... Figure 4 and Figure 5 As shown in the figure, by repeating the above process, a series of scattering images with different incident angles can be collected. Then, by analyzing this series of scattering images, the angle dependence of the scattering mode of the single crystal semiconductor can be determined.

[0045] The single-crystal semiconductor wafer measurement system of this application utilizes the strong penetrating properties of X-rays and the Bragg diffraction effect of the silicon substrate of single-crystal semiconductors. The X-ray beam emitted by the second light source system 4 contains multiple rays with different incident angles. Only the ray beam whose incident angle meets the Bragg diffraction conditions of the single-crystal silicon substrate can pass through the diffraction of the single-crystal silicon substrate and be received by the second detection system 5. The diffraction direction of the diffracted X-rays can be calculated based on the landing position of the diffracted X-rays in the second detection system 5. Thus, the crystal plane orientation at the measurement point can be calculated based on the angle relationship of Bragg diffraction. This allows CD-SAXS measurement and crystal plane orientation measurement of the sample at the measurement point to be performed simultaneously without the need for a fine angle scanning process, which greatly reduces the measurement time and improves the measurement efficiency. Moreover, it is not affected by the surface morphology of the sample (such as surface roughness, etching patterns, etc.), resulting in higher accuracy of the measurement results.

[0046] Furthermore, in some embodiments, the second light source system 4 emits a cone-shaped X-ray beam, and the focal point of the cone-shaped X-ray beam coincides with the measurement point on the sample.

[0047] Specifically, the cone-beam incident X-ray beam contains a series of X-rays at a series of incident angles (relative to the sample surface normal) to ensure that there are X-rays at this series of incident angles that can satisfy the Bragg diffraction principle.

[0048] Furthermore, the second detection system 5 includes a two-dimensional array X-ray detector, which includes multiple pixels, and the line connecting each pixel and the measurement point forms a specific angle with the optical path formed by the first X-ray.

[0049] It should be noted that the relative spatial position between the second detection system 5 and the optical path formed by the first X-ray is preset, so that the line connecting each pixel and measurement point in the two-dimensional array X-ray detector forms a specific angle with the optical path formed by the first X-ray, and this specific angle is known in advance.

[0050] Specifically, the second light source system 4 emits multiple second X-rays at different angles. When the second X-rays at different incident angles diffract at the measurement point of the sample, their diffraction angles are also different. Therefore, the second detection system 5 in this embodiment adopts a two-dimensional array X-ray detector to ensure that the diffracted X-rays of the second X-rays at different incident angles can be detected.

[0051] Furthermore, the calculation module is used to identify the target pixel of the diffracted X-ray based on the landing position of the diffracted X-ray, and calculate the diffraction angle of the diffracted X-ray based on Bragg's law of diffraction. Then, based on the diffraction angle and the target specific angle corresponding to the target pixel, it calculates the angle between the normal of the plane where the measurement point is located and the light path.

[0052] Specifically, after receiving the diffracted X-rays, the second detection system 5 identifies all the pixels irradiated by the diffracted X-rays, and then selects the pixel with the highest intensity in the diffraction spot as the target pixel. A line is formed connecting the measurement point and the target pixel, and the angle between this line and the plane where the measurement point is located is the diffraction angle. This diffraction angle can be calculated using the Bragg diffraction formula, as follows:

[0053] 2dsinθ=nλ;

[0054] Where d is the interplanar spacing of the single-crystal silicon substrate, λ is the wavelength of the monochromatic X-ray beam, θ is the diffraction angle, and n is the diffraction order. The interplanar spacing of the single-crystal silicon substrate, the wavelength of the monochromatic X-ray beam, and the diffraction order can all be known in advance, thus allowing the diffraction angle to be calculated.

[0055] The specific angle between the line connecting each pixel and the measurement point and the optical path is known in advance. By combining the diffraction angle and the specific angle of the target, the angle between the normal of the plane where the measurement point is located and the optical path can be calculated.

[0056] The calculation process for the included angle is expressed as follows:

[0057]

[0058] Where β represents the angle between the normal to the plane where the measurement point is located and the optical path, and θ represents the diffraction angle. This represents the specific angle between the line connecting the target pixel and the measurement point and the optical path.

[0059] Specifically, please refer to Figure 6As shown, Figure 6 Images (a) and (b) show the angle between the normal to the plane containing the measurement point and the optical path under two different conditions. The plane containing the measurement point and the normal to the plane containing the measurement point are perpendicular to each other. Figure 6 As shown in (a), from Figure 6 As shown in (b), Therefore, the calculation process for the included angle is expressed as follows: Furthermore, when the normal of the plane where the measurement point is located coincides with the optical path, the angle between the normal of the plane where the measurement point is located and the optical path is 0.

[0060] For further details, please refer to Figure 2 The single-crystal semiconductor wafer measurement system also includes a vacuum collimation system 6, which is located between the first light source system 1 and the multi-degree-of-freedom positioning platform 2. The vacuum collimation system 6 has a first slit 61, a second slit 62 and a third slit 63 arranged sequentially inside it. The first slit 61 and the second slit 62 are in a vacuum environment. The light path formed by the first X-ray passes through the first slit 61, the second slit 62 and the third slit 63 in sequence to irradiate the sample.

[0061] Specifically, the first slit 61 and the second slit 62 are in a vacuum environment, so that the optical path formed by the first X-ray between the first slit 61 and the second slit 62 is in a vacuum environment to reduce the attenuation effect of air on the X-ray beam. Therefore, the first slit 61 should be set close to the first light source system 1, and the second slit 62 should be set close to the multi-degree-of-freedom positioning platform 2.

[0062] For further details, please refer to Figure 2 The single-crystal semiconductor wafer measurement system also includes a vacuum scattering system 7, which is located between the multi-degree-of-freedom positioning platform 2 and the first detection system 3. The vacuum scattering system 7 includes a high-vacuum cavity for transmitting the scattering image to the first detection system 3.

[0063] Specifically, the vacuum scattering system 7 includes a high-vacuum cavity for transmitting the scattering image to the first detection system 3, which can reduce the attenuation of the scattering signal by air during transmission.

[0064] Figure 7 This is a schematic flowchart of a single-crystal semiconductor wafer measurement method according to an embodiment of the present invention. The single-crystal semiconductor wafer measurement method is applied to a single-crystal semiconductor wafer measurement system according to any of the above embodiments. The single-crystal semiconductor wafer measurement system includes a first light source system, a multi-degree-of-freedom positioning platform, a first detection system, a second light source system, a second detection system, and a computing module. The single-crystal semiconductor wafer measurement method includes:

[0065] Step S1: Control the multi-degree-of-freedom positioning platform to rotate so that the sample is at a preset angle.

[0066] Specifically, the preset angle is pre-set. In this embodiment, multiple angles are pre-set, and the multi-degree-of-freedom positioning platform rotates so that the sample is measured at each preset angle to obtain a series of scattering images at different angles.

[0067] Step S2: Control the first light source system and the second light source system to start working. The first light source system emits first X-rays and the second light source system emits second X-rays at multiple angles, which irradiate the measurement points of the sample.

[0068] Step S3: Use the first detector to collect the scattering image formed by the measurement point of the sample under the first X-ray irradiation, and at the same time control the second detector to collect the diffracted X-rays formed by the measurement point of the sample under the second X-ray irradiation, and identify the landing point of the diffracted X-rays.

[0069] Step S4: Analyze the landing point position using the calculation module to obtain the orientation information of the plane where the measurement point is located.

[0070] Control the multi-degree-of-freedom positioning platform to rotate to different preset angles, and repeat steps S2 to S4 until the measurement is completed.

[0071] It should be noted that for details of the specific implementation process of steps S1 to S4 above, please refer to the content described in the embodiment of the single-crystal semiconductor wafer measurement system, which will not be repeated here.

[0072] This embodiment of the single-crystal semiconductor wafer measurement method utilizes the strong penetrating properties of X-rays and the Bragg diffraction effect of the silicon substrate in single-crystal semiconductors. The X-ray beam emitted by the second light source system contains multiple rays with different incident angles. Only the ray beam whose incident angle meets the Bragg diffraction conditions of the single-crystal silicon substrate can pass through the diffraction of the single-crystal silicon substrate and be received by the second detection system. The diffraction direction of the diffracted X-rays can be calculated based on the landing position of the diffracted X-rays in the second detection system. Thus, the crystal plane orientation at the measurement point can be calculated based on the angle relationship of Bragg diffraction. This allows CD-SAXS measurement and measurement of the crystal plane orientation of the sample at the measurement point to be performed simultaneously without the need for fine angle scanning, greatly reducing the measurement time and improving the measurement efficiency. Furthermore, it is not affected by the surface morphology of the sample (such as surface roughness, etching patterns, etc.), resulting in higher accuracy of the measurement results.

[0073] Furthermore, the second detection system includes a two-dimensional array X-ray detector, which includes multiple pixels, and the line connecting each pixel and the measurement point forms a specific angle with the optical path formed by the first X-ray.

[0074] Therefore, step S4 specifically includes:

[0075] 1. The calculation module determines the target pixel of the diffracted X-ray landing point based on the landing point position of the diffracted X-ray.

[0076] 2. The calculation module calculates the diffraction angle of the diffracted X-rays based on Bragg's law of diffraction.

[0077] Specifically, after receiving the diffracted X-rays, all pixels irradiated by the diffracted X-rays are identified. Then, the pixel with the highest intensity in the diffraction spot is selected as the target pixel. A line is formed connecting the measurement point and the target pixel. The angle between this line and the plane containing the measurement point is the diffraction angle, which can be calculated using the Bragg diffraction formula, as follows:

[0078] 2dsinθ=nλ;

[0079] Where d is the interplanar spacing of the single-crystal silicon substrate, λ is the wavelength of the monochromatic X-ray beam, θ is the diffraction angle, and n is the diffraction order. The interplanar spacing of the single-crystal silicon substrate, the wavelength of the monochromatic X-ray beam, and the diffraction order can all be known in advance, thus allowing the diffraction angle to be calculated.

[0080] 3. The calculation module calculates the angle between the normal of the plane where the measurement point is located and the optical path based on the diffraction angle and the specific angle of the target pixel.

[0081] The calculation process for the included angle is expressed as follows:

[0082]

[0083] Where β represents the angle between the normal to the plane where the measurement point is located and the optical path, and θ represents the diffraction angle. This represents the specific angle between the line connecting the target pixel and the measurement point and the optical path.

[0084] The above are merely embodiments of this application and do not limit the scope of this patent application. Any equivalent structural or procedural changes made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of this application.

Claims

1. A single-crystal semiconductor wafer measurement system, comprising a first light source system, a multi-degree-of-freedom positioning platform, and a first detection system arranged sequentially, wherein the first light source system emits first X-rays that irradiate a measurement point of a sample on the multi-degree-of-freedom positioning platform, and the first detection system detects the scattering image formed by the first X-rays passing through the sample, characterized in that, It also includes: The second light source system has a pre-set relative spatial position to the light path formed by the first X-ray, and is used to emit second X-rays from multiple angles, wherein the focal point of the second X-rays from multiple angles coincides with the measurement point on the sample. The second detection system is pre-set in relative spatial position to the optical path formed by the first X-ray, and is used to receive the diffracted X-rays formed by the second X-ray irradiating the sample, and to identify the landing point of the diffracted X-rays. The calculation module, electrically connected to the second detection system, is used to analyze the position of the landing point based on the Bragg diffraction principle to obtain the orientation information of the plane where the measurement point is located; The second detection system includes a two-dimensional array X-ray detector, which includes multiple pixels. The line connecting each pixel and the measurement point forms a specific angle with the optical path formed by the first X-ray. The calculation module is used to determine the target pixel of the diffracted X-ray landing point based on the landing point position of the diffracted X-ray, and calculate the diffraction angle of the diffracted X-ray based on the Bragg diffraction principle. Then, based on the diffraction angle and the target specific angle corresponding to the target pixel, it calculates the angle between the normal of the plane where the measurement point is located and the optical path.

2. The single-crystal semiconductor wafer measurement system according to claim 1, characterized in that, The second light source system emits a cone-shaped X-ray beam, and the focal point of the cone-shaped X-ray beam coincides with the measurement point on the sample.

3. The single-crystal semiconductor wafer measurement system according to claim 1, characterized in that, The calculation process for the included angle is expressed as follows: Where β represents the angle between the normal to the plane where the measurement point is located and the optical path, and θ represents the diffraction angle. This represents the specific angle between the line connecting the target pixel and the measurement point and the optical path.

4. The single-crystal semiconductor wafer measurement system according to claim 1, characterized in that, It also includes a vacuum collimation system, which is located between the first light source system and the multi-degree-of-freedom positioning platform. The vacuum collimation system has a first slit, a second slit, and a third slit arranged sequentially within it. The first slit and the second slit are in a vacuum environment. The light path formed by the first X-ray passes through the first slit, the second slit, and the third slit in sequence to irradiate the sample.

5. The single-crystal semiconductor wafer measurement system according to claim 1, characterized in that, It also includes a vacuum scattering system, which is disposed between the multi-degree-of-freedom positioning platform and the first detection system. The vacuum scattering system includes a high-vacuum cavity for transmitting the scattering image to the first detection system.

6. A method for measuring single-crystal semiconductor wafers, characterized in that, It is applied to the single-crystal semiconductor wafer measurement system according to any one of claims 1-5; the method includes: S1. Control the rotation of the multi-degree-of-freedom positioning platform so that the sample is at a preset angle; S2. Control the first light source system and the second light source system to emit second X-rays at multiple angles to irradiate the measurement points of the sample; S3. Use the first detector to collect the scattering image formed by the measurement point of the sample under the first X-ray irradiation, and at the same time control the second detector to collect the diffracted X-rays formed by the measurement point of the sample under the second X-ray irradiation, and identify the landing position of the diffracted X-rays. S4. Using the calculation module based on the Bragg diffraction principle, analyze the position of the landing point to obtain the orientation information of the plane where the measurement point is located; Control the multi-degree-of-freedom positioning platform to rotate to different preset angles, and repeat steps S2 to S4 until the measurement is completed.

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