Coherent diffraction imaging method, device and system

Abstract

The invention provides a coherent diffraction imaging method, device and system. The coherent diffraction imaging system comprises an off-axis illumination module, a displacement table, a detector and control equipment, the off-axis illumination module is used for synthesizing the coherent point light sources into off-axis illumination light spots and irradiating the off-axis illumination light spots on the surface of a measured object; the displacement table is used for placing a measured object and moves under the control of the control equipment so as to enable the light spots to irradiate different areas on the surface of the measured object; the detector is used for detecting a diffraction intensity pattern of an area irradiated by the light spot on the surface of the detected object in the moving process of the displacement table; and the control equipment is used for reconstructing the surface information of the measured object according to the diffracted intensity patterns of different areas on the surface of the measured object. The coherent point light sources are synthesized into light spots of off-axis illumination through the off-axis illumination module, the numerical aperture of illumination can be effectively improved, and therefore the resolution of coherent diffraction imaging is improved.

Description

Technical Field

[0001] The present application relates to the technical field of coherent diffraction imaging. More specifically, the present application relates to a coherent diffraction imaging method, device and system. Background Art

[0002] Coherent diffraction imaging is a lensless imaging method. Compared to traditional imaging methods, it does not require an imaging objective, thus achieving imaging resolution close to the diffraction limit. Spatial scanning coherent diffraction imaging, also known as stacked imaging, is commonly used to achieve coherent diffraction imaging.

[0003] Increasing the numerical aperture of illumination can improve the resolution of stacked imaging methods. Related technologies typically use spherical wave-based disk illumination and multi-angle oblique illumination to increase the numerical aperture of illumination. However, the light intensity of disk illumination is primarily concentrated in the central region, which has little effect on improving resolution. Multi-angle oblique illumination requires recording coherent diffraction images at different oblique angles during each movement, resulting in large data volumes and long reconstruction times. Summary of the Invention

[0004] Based on the above technical defects, the present application proposes a coherent diffraction imaging method, device and system, which synthesizes coherent point light sources into off-axis illumination spots through an off-axis illumination module, effectively increasing the illumination numerical aperture and thus improving the resolution of coherent diffraction imaging.

[0005] In a first aspect, the present application provides a coherent diffraction imaging system, comprising an off-axis illumination module, a translation stage, a detector, and a control device;

[0006] The off-axis illumination module is used to synthesize coherent point light sources into an off-axis illumination spot and illuminate the surface of the object to be measured;

[0007] The translation stage is used to place the object to be measured and move it under the control of the control device so that the light spot can illuminate different areas on the surface of the object to be measured;

[0008] The detector is used to detect the diffraction intensity pattern of the area on the surface of the object being measured that is illuminated by the light spot during the movement of the translation stage;

[0009] The control device is used to reconstruct the surface information of the object under test based on the diffraction intensity patterns of different areas on the surface of the object under test.

[0010] The second aspect of the present application provides a coherent diffraction imaging method, which is applied to the coherent diffraction imaging system provided in the first aspect of the present application, comprising:

[0011] Obtaining diffraction intensity maps detected for different areas of the surface of the object being measured; the diffraction intensity map of each area is detected when the off-axis illumination spot illuminates the corresponding area;

[0012] The surface information of the object being measured is reconstructed based on the diffraction intensity patterns of different areas on the surface of the object being measured.

[0013] A third aspect of the present application provides a coherent diffraction imaging device, which is applied to the coherent diffraction imaging system provided in the first aspect of the present application, comprising:

[0014] An acquisition module is used to acquire diffraction intensity maps detected for different areas on the surface of the object being measured; the diffraction intensity map of each area is detected when the off-axis illumination spot illuminates the corresponding area;

[0015] The reconstruction module is used to reconstruct the surface information of the object under test based on the diffraction intensity maps of different areas on the surface of the object under test.

[0016] The beneficial effects of this application include at least:

[0017] In the embodiments of the present application, the off-axis illumination module is used to synthesize coherent point light sources into off-axis illumination spots, which can effectively increase the numerical aperture of the illumination, thereby improving the resolution of coherent diffraction imaging. In addition, the illumination light source of the coherent diffraction imaging system provided in the embodiments of the present application is synthesized, so the light spot can be synthesized according to the required light intensity distribution. Compared with the situation where the light intensity of the disk illumination based on spherical waves is concentrated in the central area, it can more effectively improve the imaging resolution. Moreover, the synthetic light spot illumination only needs to be recorded once at each moving position. Compared with the technical solution of using multi-angle tilt illumination, which requires recording multiple angles of illumination for each movement, the data volume is smaller and the reconstruction time is shorter. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present application and, together with the description, serve to explain the principles of the present application.

[0019] The present application can be more clearly understood from the following detailed description with reference to the accompanying drawings, in which:

[0020] Figure 1 A schematic block diagram of a coherent diffraction imaging system provided by an exemplary embodiment of the present application is shown;

[0021] Figure 2 A schematic diagram of an off-axis illumination spot pattern provided in an embodiment of the present application is shown;

[0022] Figure 3 A schematic diagram showing a light spot formed by a moving trajectory of a coherent point light source provided by an exemplary embodiment of the present application is shown;

[0023] Figure 4 FIG2 shows a schematic structural diagram of a coherent diffraction imaging system provided by an exemplary embodiment of the present application;

[0024] Figure 5 A schematic flow chart of a coherent diffraction imaging method provided by an exemplary embodiment of the present application is shown;

[0025] Figure 6 A schematic diagram of a coherent diffraction device provided by an exemplary embodiment of the present application is shown;

[0026] Figure 7 A schematic structural diagram of an electronic device provided by an exemplary embodiment of the present application is shown. DETAILED DESCRIPTION

[0027] Hereinafter, embodiments of the present application will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present application. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present application. It is obvious to those skilled in the art that the present application can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present application, some technical features known in the art are not described.

[0028] It should be noted that the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should also be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of the features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0029] Now, exemplary embodiments according to the present application will be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in a variety of different forms and should not be construed as being limited to the embodiments described herein. The accompanying drawings are not drawn to scale, and certain details may be magnified and omitted for the purpose of clarity. The shapes of the various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are merely exemplary and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may further design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0030] The following describes exemplary embodiments of the present application. It should be noted that the following embodiments are merely provided to facilitate understanding of the spirit and principles of the present application, and the embodiments of the present application are not limited in this respect. On the contrary, the embodiments of the present application can be applied to any applicable scenario.

[0031] As a lensless imaging method, coherent diffraction imaging does not require an imaging objective compared to traditional imaging methods, allowing imaging resolution close to the diffraction limit. In the field of short-wavelength imaging, where lens processing is more difficult, coherent diffraction imaging has enormous application potential and development prospects, and has been widely used in industries such as biomedical imaging, materials characterization, and semiconductor testing. Spatial scanning coherent diffraction imaging, also known as stack imaging, is a common coherent diffraction imaging technique. By moving the sample under test and recording the diffraction patterns at different positions, surface information of the object under test can be reconstructed. Each time the sample is moved, adjacent illumination areas must meet a certain overlap ratio. This imaging method improves the convergence speed of stack imaging by increasing the redundancy of the recorded data.

[0032] Increasing the numerical aperture of the illumination is an effective means of improving the resolution of stacked imaging methods, fully utilizing the spatial bandwidth of coherent diffraction imaging systems. Related art proposes a method for circular disk illumination based on spherical waves that can double the resolution. However, the light intensity in the central region of the disk illumination is relatively high, and this central region has little impact on the resolution improvement. Related art also proposes a method using multi-angle oblique illumination, but this method exponentially increases the amount of recorded data and reconstruction time.

[0033] Based on this, the embodiments of the present application propose a coherent diffraction imaging method, device, and system for illumination by synthesizing off-axis illumination spots. By synthesizing coherent point light sources into off-axis illumination spots through an off-axis illumination module, the numerical aperture of the illumination can be effectively increased, thereby improving the resolution of coherent diffraction imaging. In addition, the illumination light source of the coherent diffraction imaging system provided by the embodiments of the present application is synthesized, so the spot can be synthesized according to the required light intensity distribution. Compared with the situation where the light intensity of the disk illumination based on spherical waves is concentrated in the central area, the imaging resolution can be more effectively improved. Moreover, the synthetic spot illumination only needs to be recorded once at each moving position. Compared with the technical solution of using multi-angle oblique illumination, which requires recording multiple angles of illumination for each movement, the data volume is smaller and the reconstruction time is shorter.

[0034] refer to Figure 1 , is a coherent diffraction imaging system provided in an embodiment of the present application, the system comprising: an off-axis illumination module 101, a translation stage 102, a detector 103 and a control device 104.

[0035] The off-axis illumination module 101 is used to combine coherent point light sources into an off-axis illumination spot, which is then illuminated onto the surface of the object being measured. Coherent point light sources can produce coherent point light sources. It should be noted that the aforementioned coherent and point light sources are both physically ideal. In some embodiments, the coherent point light source can be a laser.

[0036] Light spots are synthesized from coherent point light sources. In some embodiments, light spots can be generated by rapidly changing the beam angle of a coherent point light source. Due to the high speed, when observed by the human eye or by a detection device such as detector 103 on a specific plane, what is observed is a pattern composed of the trajectory formed by the movement of the coherent point light source's beam on the detection plane during the acquisition period, rather than the point formed by the coherent point light source's beam on the plane at a specific moment.

[0037] Based on this, the aforementioned high speed refers to a speed that causes the light beam to move at a speed exceeding a preset speed threshold, which can be determined based on parameters such as the acquisition time of the detector 103. Specifically, in actual applications, it is possible to not calculate a specific preset speed threshold, and simply set a relatively high speed so that no change in the light spot pattern is visible when observed directly by the human eye or through the detector 103.

[0038] Optionally, the light beam of the high-speed moving coherent point light source is specifically implemented in ways including but not limited to: changing the optical path of the light beam generated by the coherent point light source through a module such as a lens / reflector that moves at high speed (such as rotating / vibrating); or, generating a high-speed moving coherent point light source through a light source generating module that moves at high speed (such as rotating / vibrating), etc., which is not limited in the embodiments of the present application.

[0039] In addition, in some embodiments, when the illumination area of ​​the light spot synthesized by the coherent point light source directly incident on the surface of the object to be measured is large, the light spot can be focused onto the surface of the object to be measured through a concave lens or other lens group that can reduce the light spot size, thereby reducing the illumination area of ​​the light spot on the surface of the object to be measured.

[0040] The translation stage 102 is used to place the object under test and is moved under the control of the control device 104 so that the light spot illuminates different areas on the surface of the object under test. The translation stage 102 is a controllable translation stage that can be moved to a specified position under the control of the control device 104. In some embodiments, the translation stage 102 may have certain computing capabilities, and the control device 104 can directly input multiple specified position information to the translation stage 102, and the translation stage 102 can calculate the movement parameters such as the trajectory and speed to ensure that the translation stage 102 passes through each specified position. In other embodiments, the control device 104 can calculate the movement parameters and send them to the translation stage 102, which then executes them according to the parameters.

[0041] The detector 103 is used to detect the diffraction intensity pattern of the area on the surface of the object being measured that is illuminated by the light spot during the movement of the translation stage 102. Optionally, the detector 103 can collect data at a preset acquisition frequency, which can be adapted to the movement of the translation stage 102, so that the detector 103 can capture diffraction intensity patterns of different areas. Alternatively, the detector 103 can be controlled by the control device 104, which controls the detector 103 to begin detection after determining that the translation stage 102 has moved to the currently designated area. The detection implementation method can be set according to the specific situation, and the present embodiment will not cite examples one by one.

[0042] In some embodiments, the object under test may be a wafer, a mask, etc., and the reconstructed surface information can represent information such as protrusions and grooves on the surface of the object under test, thereby determining the pattern of the surface of the object under test, such as the circuit pattern on the surface of the mask.

[0043] The control device 104 is used to control the movement of the translation stage and reconstruct surface information of the object under test based on the diffraction intensity patterns of different regions of the object's surface. The control device 104 can control the movement of the translation stage so that the detector 103 can detect the region of interest on the object's surface. The reconstruction algorithm used can include a stacked reconstruction algorithm, which reconstructs surface information such as the complex amplitude distribution and illumination spot distribution of the object's surface through numerical iteration.

[0044] The coherent diffraction imaging method provided in the embodiment of the present application, compared to the traditional stacked imaging method, uses an off-axis illumination mode. The off-axis illumination module synthesizes the coherent point light source into an off-axis illumination spot, effectively increasing the illumination numerical aperture and achieving higher imaging resolution. In addition, the illumination light source of the coherent diffraction imaging system provided in the embodiment of the present application is synthetic, so the spot can be synthesized according to the required light intensity distribution. Compared with the situation where the light intensity of the disk illumination based on spherical waves is concentrated in the central area, it can more effectively improve the imaging resolution. Moreover, the synthetic spot illumination only needs to be recorded once at each moving position. Compared with the technical solution using multi-angle tilt illumination, which requires recording multiple angles of illumination for each movement, the data volume is smaller and the reconstruction time is shorter.

[0045] In some embodiments, the off-axis lighting module 101 may include the following modules:

[0046] A light source generating module, used to generate a coherent point light source;

[0047] A galvanometer module, comprising a galvanometer, the galvanometer module being configured to move the galvanometer at a first trajectory and a first speed under the control of a control device so as to synthesize coherent point light sources incident on the galvanometer into a light spot;

[0048] The imaging module is used to image the light spot onto the surface of the object being measured.

[0049] The first speed may exceed the aforementioned preset speed threshold, and the first trajectory forms a light spot pattern. Optionally, the trajectory of the galvanometer movement may be controlled by a control device, which may generate the first trajectory based on the desired light spot pattern irradiated onto the surface of the object under test. Because the galvanometer movement speed is high, exceeding the resolution capability of the human eye / detector, the point light source is observed as a light spot.

[0050] The coherent point light source is synthesized into an off-axis illumination spot by the galvanometer in the galvanometer module, which is a Fourier synthesis lighting technology. Figure 2 The following are examples of spot patterns observed on a plane. From left to right, they are off-axis illumination using dipole illumination, quadrupole illumination, and annular illumination. Each spot pattern is a trajectory formed by the high-speed movement of a coherent point light source beam, as shown in Figure 1. Figure 3 The figure shows an example of a light spot pattern formed by an exemplary motion trajectory. Compared to disk illumination modes, which concentrate light energy in a central area, the off-axis illumination modes described above, such as dipole, quadrupole, and annular illumination, can concentrate the energy of the coherent point light source beam more closely in the off-axis angle region of the light spot. Furthermore, because the light intensity in off-axis angle regions is more effective in improving imaging resolution, they can more effectively improve the energy utilization of the light source, avoid wasting light source energy, and further enhance imaging resolution.

[0051] Optionally, the movement may include vibration, rotation, etc., thereby changing the emission angle of the coherent point light source incident on the galvanometer. In some embodiments, the galvanometer can rotate / vibrate about a center point. Optionally, the galvanometer can be a lens or a reflector, which is not limited to this. For example, the galvanometer can be a micro-electro-mechanical system (MEMS) reflector capable of two-dimensional scanning. The MEMS reflector can achieve high-speed, stable, and accurate movement, thereby improving the effect of the light spot imaging pattern.

[0052] For example, Figure 4 As shown, the light source generating module may be a laser 401, and the coherent point light source generated is laser. The galvanometer module includes a galvanometer 403, which is a reflector that can vibrate at a high frequency under the control of a control device 408 to synthesize a light spot of a specified pattern.

[0053] In some embodiments, the control device is also used to control the movement of the translation stage so that there is an overlap between every two adjacent areas in different areas. When the translation stage moves, it can move based on the order of adjacent areas, or it can move in a disordered order, that is, the surface areas of the object to be measured corresponding to the previous position and the next position of the translation stage are not adjacent, and the embodiments of the present application are not limited thereto. An example of a movement method is a "bow" shaped movement path. The overlapping areas can meet certain area requirements, such as when the overlapping area exceeds a preset threshold, for example, when the overlapping area of ​​two adjacent areas exceeds 60%. By controlling the movement of the translation stage through the control device, the control device can determine the position of the detector shooting, which helps the control device to realize the reconstruction process more quickly.

[0054] The following combination Figure 4 , an example coherent diffraction imaging system is described as follows:

[0055] Laser 401 generates a laser beam. It should be noted that, in theory, laser is a beam of parallel light, but in reality, laser has a certain divergence angle. Therefore, the laser beam can be focused onto plane mirror 403 through ellipsoidal reflector 402, and the focus can fall on the surface of reflector 403.

[0056] Mirror 403 is a MEMS mirror capable of two-dimensional scanning. Control device 408 controls the deflection angle of mirror 403, achieving high-frequency vibration. This high-frequency rotation of mirror 403 creates a scanning trajectory on ellipsoidal mirror 404, resulting in a light spot conforming to an off-axis illumination pattern on sample 405. This illumination method allows the incident angle of the light beam to be controlled without changing its position on sample 405, thereby achieving off-axis illumination with varying patterns.

[0057] An example of an off-axis illumination pattern is Figure 2 As shown, it includes dipole illumination, quadrupole illumination, and annular illumination, among which annular illumination can provide higher resolution for patterns in various directions on the sample 405 to be measured, and can better adapt to patterns in different directions.

[0058] The light beam reflected by reflector 403 is reflected by ellipsoidal mirror 404 onto sample 405 (the object being measured). The front focal plane of ellipsoidal mirror 404 is located on reflector 403, and the back focal plane is located on sample 405. This means that the light spot on reflector 403 is imaged onto sample 405. The scale factor of the light spot size on sample 405 is determined based on the processing parameters of ellipsoidal mirror 404.

[0059] The sample 405 is mounted on a translation stage 406, whose movement is controlled by a control device 408, enabling large-area scanning and imaging of the sample 405. A highly sensitive detector 407 records the scattered light beam from the sample 405 and uploads it to the control device 408, which then processes the data and performs surface reconstruction.

[0060] Each time the sample 405 is moved, the detector 407 records a diffraction intensity pattern, ensuring that two adjacent illumination areas overlap to a certain extent, such as ensuring that the overlap rate of adjacent illumination areas is greater than 60%, until the entire sample area of ​​the sample 405 is scanned and recorded. Optionally, the detector 407 can be set to an integration mode to record the integrated diffraction intensity pattern. The diffraction intensity pattern detected by the detector 407 in the integration mode is used to represent the distribution of the integrated diffraction intensity.

[0061] Detector 407 records a diffraction intensity pattern in integration mode. The sample is then moved and recorded again until the object surface's region of interest is scanned. During the sample's movement, the overlap between adjacent illumination areas is maintained at a minimum of 60%. After recording is complete, a stacked reconstruction algorithm is used to numerically iteratively reconstruct the complex amplitude distribution and illumination spot distribution on the object surface.

[0062] In some embodiments, in order to simplify the reconstruction calculation complexity and reduce the reconstruction time, after recording the diffraction intensity map of the entire area of ​​the sample 405 under test, the sample 405 under test can be replaced with a plane mirror, and a reflection light beam intensity map without an object is recorded. Together with the random phase distribution, it constitutes the initial recording surface complex amplitude guess distribution, which is substituted into the stacked reconstruction algorithm to complete the reconstruction of the sample 405 under test and the illumination light beam.

[0063] above Figure 4 For reflective stacked imaging optical path, in other embodiments, Fourier synthesis illumination technology can also be combined with the transmissive stacked imaging optical path to achieve high-resolution imaging. Specifically, in the transmissive stacked imaging optical path, Figure 4 Taking the difference of the coherent diffraction imaging system shown as an example, the sample 405 to be measured does not reflect the light beam to the detector 407, but transmits the light beam to the detector 407. Accordingly, the detector 407 is set on the back of the sample 405 to be measured, and the translation stage 406 can place the sample 405 to be measured by hollowing and embedding.

[0064] The coherent diffraction imaging system provided in this embodiment is based on the coherent diffraction imaging method of Fourier synthesis illumination. Through the programming control of the control device, rapid vibration scanning of the galvanometer mirror group is realized to obtain arbitrary off-axis illumination modes, including different illumination spot sizes, illumination shapes, etc. A light beam with a certain off-axis angle is used as an illumination probe to illuminate the sample under test position by position. The detector records a set of diffraction intensity patterns, and then uses the stacking reconstruction algorithm to reconstruct the complex amplitude distribution of the sample under test.

[0065] Compared to stacked imaging methods using other illumination modes, the off-axis illumination mode effectively increases the numerical aperture of the illumination, enabling the recording of more high-frequency information from the sample being measured, and achieving higher resolution. Spherical wave-based disk illumination can also increase the numerical aperture of the illumination, and the larger the illumination spot, the more off-axis illumination components there are. However, the light beam at the center of the disk has little effect on improving resolution. Using Fourier synthesis illumination technology to implement the off-axis illumination mode can concentrate the beam energy in the off-axis angle region, increasing the proportion of light intensity at large illumination angles in the total light intensity, improving the utilization rate of the light spot energy, and thus improving the contrast of the diffraction signal. If a multi-angle oblique illumination method is used, it is necessary to record the diffraction intensity patterns corresponding to multiple off-axis angles at a single object surface scanning position. The stacked imaging method, in turn, requires scanning and recording multiple object surface positions. Therefore, the multi-angle oblique illumination method exponentially increases the speed of recording and reconstruction, thereby exacerbating the impact of problems such as beam drift and mechanical instability. The coherent diffraction imaging system of the present application embodiment does not have this problem, reducing the amount of data recorded and reconstructed and the speed. In addition, by utilizing the detector's integration mode, diffraction intensity data with high signal-to-noise ratio can be recorded, providing a new high-resolution coherent diffraction imaging solution.

[0066] Some embodiments of the present application also provide a coherent diffraction imaging method, which is applied to the coherent diffraction imaging system provided in the embodiments of the present application. In some embodiments, the method can be applied to a control device in the coherent diffraction imaging system provided in the embodiments of the present application. For any portions of the coherent diffraction imaging method provided in the embodiments of the present application that are not fully described, including example implementation details and beneficial effects, please refer to the relevant description of the coherent diffraction imaging system provided in the embodiments of the present application.

[0067] like Figure 5 As shown, the coherent diffraction imaging method provided in the embodiment of the present application includes the following steps 501 to 502:

[0068] Step 501: Obtain diffraction intensity maps detected at different areas on the surface of the object being measured.

[0069] The diffraction intensity pattern of each area is detected when the off-axis illumination spot illuminates the corresponding area.

[0070] Step 502: Reconstructing surface information of the object under test based on diffraction intensity maps of different regions on the surface of the object under test.

[0071] Furthermore, before obtaining the diffraction intensity map detected for different areas of the surface of the object to be measured, the detector used to detect the diffraction intensity map can also be controlled to operate in an integral mode; wherein the diffraction intensity map detected by the detector in the integral mode is used to represent the distribution of the diffraction integrated intensity.

[0072] In some embodiments, before obtaining the diffraction intensity maps detected for different areas on the surface of the object to be measured, the galvanometer may be controlled to move at a first trajectory and a first speed so that the coherent point light source incident on the galvanometer forms a light spot.

[0073] In some embodiments, before controlling the galvanometer to move at the first trajectory and the first speed, the trajectory of the galvanometer movement may be determined according to the target light spot pattern to obtain the first trajectory. The target light spot pattern is a preset pattern.

[0074] Furthermore, before obtaining the diffraction intensity maps detected for different areas on the surface of the object to be measured, the translation stage used to place the object to be measured can be controlled to move so that the light spot illuminates different areas on the surface of the object to be measured, and every two adjacent areas overlap.

[0075] The embodiments of the present application do not limit the order in which the processes are executed. In actual applications, processes that do not have a dependency relationship can be executed in parallel or in any order. If the output of one process serves as the input of another process, the two processes are considered to have a dependency relationship.

[0076] In the embodiments of the present application, the processing details of each step can refer to the relevant processing process in the aforementioned coherent diffraction imaging system, and will not be repeated here.

[0077] Some embodiments of the present application also provide a coherent diffraction imaging device, which is applied to the coherent diffraction imaging system provided in the embodiments of the present application and can be used to implement the coherent diffraction imaging method provided in the embodiments of the present application. In some embodiments, it can be applied to the control device of the coherent diffraction imaging system provided in the embodiments of the present application. For any portion not fully described in the coherent diffraction imaging device provided in the embodiments of the present application, reference can be made to the relevant description of the coherent diffraction imaging system provided in the embodiments of the present application.

[0078] like Figure 6 As shown, the coherent diffraction imaging device provided in the embodiment of the present application includes an acquisition module 601 and a reconstruction module 602.

[0079] The acquisition module 601 is used to acquire diffraction intensity maps detected for different areas of the surface of the object under test; the diffraction intensity map of each area is detected when the off-axis illumination spot illuminates the corresponding area;

[0080] The reconstruction module 602 is used to reconstruct the surface information of the object under test based on the diffraction intensity patterns of different areas on the surface of the object under test.

[0081] The coherent diffraction imaging method provided in the embodiment of the present application and the coherent diffraction imaging system provided in the embodiment of the present application are based on the same application concept and have the same beneficial effects as the methods adopted, operated or implemented therein.

[0082] Please refer to the following Figure 7 , which shows a schematic diagram of an electronic device provided by some embodiments of the present application. Figure 7 As shown, the electronic device 7 includes: a processor 700, a memory 701, a bus 707 and a communication interface 703, and the processor 700, the communication interface 703 and the memory 701 are connected via the bus 707; the memory 701 stores a computer program that can be run on the processor 700, and when the processor 700 runs the computer program, it executes the coherent diffraction imaging method provided by any of the aforementioned embodiments of the present application.

[0083] Memory 701 may include high-speed random access memory (RAM) and may also include non-volatile memory, such as at least one disk storage. Communication between the system network element and at least one other network element is achieved through at least one communication interface 703 (which may be wired or wireless), and may use the Internet, a wide area network, a local area network, a metropolitan area network, etc.

[0084] The bus 707 may be an ISA bus, a PCI bus, or an EISA bus. The bus may be divided into an address bus, a data bus, a control bus, etc. The memory 701 is used to store programs, and the processor 700 executes the programs after receiving execution instructions. The coherent diffraction imaging method disclosed in any of the aforementioned embodiments of the present application may be applied to or implemented by the processor 700.

[0085] The processor 700 may be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above method can be completed by hardware integrated logic circuits in the processor 700 or by software instructions. The processor 700 may be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it may also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), an off-the-shelf field programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the various methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor may be a microprocessor or any conventional processor. The steps of the method disclosed in conjunction with the embodiments of this application can be directly implemented and executed by a hardware decoding processor, or by a combination of hardware and software modules in the decoding processor. The software module can be located in a storage medium mature in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, etc. The storage medium is located in the memory 701 , and the processor 700 reads the information in the memory 701 and completes the steps of the above method in combination with its hardware.

[0086] The electronic device provided in the embodiment of the present application and the coherent diffraction imaging method provided in the embodiment of the present application are based on the same application concept and have the same beneficial effects as the methods adopted, operated or implemented by them.

[0087] An embodiment of the present application also provides a computer-readable storage medium corresponding to the coherent diffraction imaging method provided in the aforementioned embodiment, on which a computer program (i.e., a program product) is stored. When the computer program is run by a processor, it will execute the coherent diffraction imaging method provided in any of the aforementioned embodiments.

[0088] In addition, examples of the computer-readable storage medium may also include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other optical or magnetic storage media, which are not listed here one by one.

[0089] The computer-readable storage medium provided in the above-mentioned embodiments of the present application and the coherent diffraction imaging method provided in the embodiments of the present application are based on the same application concept and have the same beneficial effects as the methods adopted, run or implemented by the application programs stored therein.

[0090] It should be noted that the algorithms and displays provided herein are not inherently related to any particular computer, virtual device, or other device. Various general-purpose devices may also be used in conjunction with the teachings herein. The structures required to construct such devices are readily apparent from the above description. Furthermore, this application is not directed to any particular programming language. It should be understood that the content of this application described herein may be implemented using a variety of programming languages, and the above description of specific languages ​​is intended to disclose the best mode of implementation of this application.

[0091] Similarly, it should be understood that in order to streamline the present application and aid understanding of one or more of the various application aspects, in the above description of the exemplary embodiments of the present application, various features of the present application are sometimes grouped together into a single embodiment, figure, or description thereof. However, this disclosed method should not be interpreted as reflecting an intention that the claimed application requires more features than are expressly recited in each claim. Rather, as reflected in the claims below, aspects of the application lie in less than all the features of the individual embodiments disclosed above. Accordingly, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of the present application.

[0092] The various component embodiments of the present application can be implemented in hardware, or in software modules running on one or more processors, or in a combination thereof. Those skilled in the art will appreciate that a microprocessor or digital signal processor (DSP) can be used in practice to implement some or all of the functions of some or all of the components in the creation device of the virtual machine according to the embodiment of the present application. The application can also be implemented as a device or device program for executing part or all of the methods described herein. The program implementing the application can be stored on a computer-readable medium, or can have the form of one or more signals. Such a signal can be downloaded from an Internet website, or provided on a carrier signal, or provided in any other form.

[0093] The above description is merely a preferred embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A coherent diffraction imaging system, characterized in that: The system includes an off-axis illumination module, a translation stage, a detector, and a control device; The off-axis illumination module is used to synthesize coherent point light sources into an off-axis illumination light spot and illuminate the surface of the object to be measured; The translation stage is used to place the object under test and move under the control of the control device so that the light spot is irradiated to different areas on the surface of the object under test; The detector is used to detect the diffraction intensity pattern of the area on the surface of the object being measured that is illuminated by the light spot during the movement of the translation stage; The control device is used to reconstruct the surface information of the object to be measured based on the diffraction intensity maps of different areas on the surface of the object to be measured.

2. The coherent diffraction imaging system according to claim 1, characterized in that: The off-axis lighting module comprises: A light source generating module, used for generating the coherent point light source; A galvanometer module, comprising a galvanometer, wherein the galvanometer module is configured to move the galvanometer at a target trajectory and a target speed under the control of the control device so that coherent point light sources incident on the galvanometer are synthesized into the light spot; An imaging module is used to image the light spot onto the surface of the object to be measured.

3. The coherent diffraction imaging system according to claim 2, characterized in that: The control device is further configured to determine a movement trajectory of the galvanometer according to a target light spot pattern to obtain the first trajectory.

4. The coherent diffraction imaging system according to any one of claims 1 to 3, characterized in that: The control device is further configured to control the movement of the translation stage so that every two adjacent areas in the different areas overlap.

5. A coherent diffraction imaging method, characterized in that: Applied to the coherent diffraction imaging system according to any one of claims 1 to 4, the method comprising: Obtaining diffraction intensity maps detected for different areas of the surface of the object being measured; the diffraction intensity map of each area is detected when the off-axis illumination spot illuminates the corresponding area; Surface information of the object to be measured is reconstructed based on diffraction intensity maps of different areas on the surface of the object to be measured.

6. The method according to claim 5, characterized in that Before obtaining the diffraction intensity maps detected at different areas on the surface of the object being measured, the following steps are also included: A detector for detecting the diffraction intensity pattern is controlled to operate in an integration mode; wherein the diffraction intensity pattern detected by the detector in the integration mode is used to represent the distribution of the diffraction integrated intensity.

7. The method according to claim 5, characterized in that Before obtaining the diffraction intensity maps detected at different areas on the surface of the object being measured, the following steps are also included: The galvanometer is controlled to move along a first trajectory and at a first speed, so that the coherent point light source incident on the galvanometer forms the light spot.

8. The method according to claim 7, characterized in that Before controlling the galvanometer to move at the first trajectory and the first speed, the method further includes: The movement trajectory of the galvanometer is determined according to the target light spot pattern to obtain the first trajectory.

9. The method according to claim 5, characterized in that Before obtaining the diffraction intensity maps detected at different areas on the surface of the object being measured, the following steps are also included: The translation stage for placing the object to be measured is controlled to move so that the light spot illuminates different areas on the surface of the object to be measured, and every two adjacent areas overlap.

10. A coherent diffraction imaging device, characterized in that: The coherent diffraction imaging system according to any one of claims 1 to 4, wherein the device comprises: An acquisition module is used to acquire diffraction intensity maps detected for different areas on the surface of the object being measured; the diffraction intensity map of each area is detected when the off-axis illumination spot illuminates the corresponding area; The reconstruction module is used to reconstruct the surface information of the object under test according to the diffraction intensity maps of different areas on the surface of the object under test.

Images