Measuring device and measuring method for scanning and detecting three-dimensional micro-nano morphology

Abstract

The invention belongs to the field of three-dimensional micro-nano morphology detection, and relates to a measuring device and a measuring method for three-dimensional micro-nano morphology scanning detection, the measuring device for three-dimensional micro-nano morphology scanning detection comprises a white light interferometer, an imaging objective lens, a space-time scanning assembly and a data analysis and processing computer; the white light interferometer, the imaging objective lens and the space-time scanning assembly are sequentially arranged from front to back; the to-be-measured workpiece, the imaging objective lens and the space-time scanning assembly are sequentially arranged from front to back; and the space-time scanning assembly is connected with the data analyzing and processing computer. The invention provides the measuring device and the measuring method for scanning and detecting the three-dimensional micro-nano morphology, which are not limited by the space size of an area array detector and have simple and clear characteristics of a correction model.

Description

Technical Field

[0001] This invention belongs to the field of three-dimensional micro-nano topography detection, and relates to a measuring device and a measuring method, particularly a measuring device and a measuring method for three-dimensional micro-nano topography scanning detection. Background Technology

[0002] With the continuous development of micro and nano structures, the industrial demand for machine vision from artificial intelligence is becoming increasingly urgent. Traditional touch measurement is shifting to non-contact measurement, and static measurement is shifting to dynamic measurement. The resolution, measurement speed, and aspect ratio of three-dimensional micro and nano topography measurement are gradually becoming challenges.

[0003] Currently, existing methods for 3D micro / nano topography detection include: coordinate measuring machine (CMM) contact measurement, lidar non-contact spatial deflection scanning, laser interferometer array detection, and moving microscopes. The pixel count, spatial size, and aperture ratio of the array detection devices used in these methods limit the lateral resolution and field of view of the detection results. The repeatability and stability of the deflection scanning / moving components limit the spatial resolution and field of view of 3D detection. Furthermore, the measurement uncertainty of the reference point calibration in CMM systems is limited by the fabrication of the mechanical structure. Moreover, diffraction at hard boundaries is a factor affecting the measurement uncertainty at the micro / nano scale. Computational optics can effectively eliminate the influence of diffraction on the measurement results, but the effective elimination of diffraction is limited due to the multiple overlaps of diffraction phenomena in complex topography measurement environments. Three-dimensional micro-nano topography detection can also be achieved using microscope depth-of-field synthesis (focus stacking) technology and moving white light interferometer + area array detector. Both of these technologies are limited by the illumination wavelength and its diffraction limit, as well as the structural size of the area array detector. They require the magnification of the imaging optical system to match the testing requirements of micro-nano sizes. In addition, the measurement time and data model analysis and processing are cumbersome. Laser interferometers have sharp interference fringes, which require high bandwidth of the detection system and are difficult to capture. Summary of the Invention

[0004] To address the aforementioned technical problems in the background art, this invention provides a measurement device and method for three-dimensional micro-nano topography scanning and detection that is not limited by the spatial size of the area array detector and has simple and clear correction model features.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A measuring device for three-dimensional micro / nano topography scanning and detection is characterized in that: the measuring device for three-dimensional micro / nano topography scanning and detection includes a white light interferometer, an imaging objective lens, a space-time scanning component, and a data analysis and processing computer; the white light interferometer, imaging objective lens, and space-time scanning component are arranged sequentially from front to back; the workpiece to be measured, the imaging objective lens, and the space-time scanning component are arranged sequentially from front to back; the space-time scanning component is connected to the data analysis and processing computer.

[0007] The aforementioned white light interferometer includes a semiconductor pulsed laser, an upconversion plate, a collimating lens, a beam splitter, and a standard total internal reflection mirror. The semiconductor pulsed laser emits pulsed laser light. The upconversion plate, collimating lens, and beam splitter are arranged sequentially from front to back in the optical path of the pulsed laser light. The beam splitter splits the laser light incident on it into transmitted light and reflected light. The standard total internal reflection mirror is placed in the optical path of the transmitted light after passing through the beam splitter. The transmitted light after passing through the beam splitter is reflected by the standard total internal reflection mirror to form standard reflected light. The standard reflected light is incident on the beam splitter and reflected by the beam splitter to the imaging objective. The workpiece to be tested is placed in the optical path of the reflected light after passing through the beam splitter. The reflected light after passing through the beam splitter is reflected by the workpiece to form signal reflected light. The signal reflected light is incident on the beam splitter and transmitted by the beam splitter to the imaging objective.

[0008] The aforementioned upconversion plate is made of rare-earth material Yb that can excite two wavelengths. 3+ / Ho 3+ It is made of double-doped fluorine-oxysilicate glass; the semiconductor pulsed laser excites the upconversion plate to emit red light at 650nm and green light at 540nm; the beam splitter is a semi-reflective mirror; the standard total reflection mirror includes a substrate and a standard pattern disposed on the substrate; the reflectivity of the standard pattern is greater than the reflectivity of the substrate.

[0009] The aforementioned space-time scanning assembly includes a space-time scanner, a fast photodetector, and a digital oscilloscope; the standard reflected light is incident on the fast photodetector after passing through a beam splitter, an imaging objective lens, and the space-time scanner; the signal reflected light is incident on the fast photodetector after passing through a beam splitter, an imaging objective lens, and the space-time scanner; the fast photodetector is connected to a data analysis and processing computer via the digital oscilloscope.

[0010] The aforementioned spacetime scanner is wedge-shaped; the fast photodetector is attached to the wedge-shaped surface of the spacetime scanner; the standard reflected light is incident on the fast photodetector after passing through the beam splitter, imaging lens, and receiving surface of the spacetime scanner; the signal reflected light is incident on the fast photodetector after passing through the beam splitter, imaging lens, and receiving surface of the spacetime scanner.

[0011] The material of the aforementioned space-time scanner is an optical material with a high refractive index that emits red light at 650nm and green light at 540nm from the upconversion plate.

[0012] The aforementioned fast photodetector is a unit photodetector.

[0013] The aforementioned measuring device for three-dimensional micro-nano topography scanning and detection also includes a Z-axis uniform motion guide rail; the white light interferometer, imaging objective lens, and space-time scanning component are all fixed on the Z-axis uniform motion guide rail and can move freely along the axial direction of the Z-axis uniform motion guide rail.

[0014] The aforementioned data analysis and processing computer includes, in sequence from front to back, a data acquisition module, a real-time amplitude comparison module, a hard boundary correction module, a three-dimensional shape reproduction module, a statistical analysis module, and a storage module.

[0015] A measurement method for three-dimensional micro / nano topography scanning detection based on the aforementioned measurement device, characterized in that the measurement method includes the following steps:

[0016] 1) Construct the measurement device for three-dimensional micro-nano topography scanning and detection as described above;

[0017] 2) Start the Z-axis uniform motion guide rail to drive the white light interferometer, imaging objective lens and space-time scanning component to move synchronously;

[0018] 3) After entering the Z-direction measurement range, record the Z-axis coordinate z. i Simultaneously, a white light interferometer is activated to emit pulsed laser light, which, after being incident on the upconversion plate, forms two different wavelengths of fluorescence.

[0019] 4) Two different wavelengths of fluorescence are collimated by a collimating lens and then incident on a beam splitter, which splits them into transmitted light and reflected light. The transmitted light after passing through the beam splitter is reflected by a standard total internal reflection mirror to form standard reflected light. The reflected light after passing through the beam splitter is reflected by the workpiece under test to form signal reflected light.

[0020] 5) The standard reflected light and the signal reflected light are respectively incident on the imaging objective after passing through the beam splitter and are imaged on the image plane of the imaging objective and coherently correlated to obtain a coherent image.

[0021] 6) After passing the coherence image obtained in step 5) through a space-time scanner, the instantaneous morphology spatial optical signal P of the workpiece is obtained. xy Converted into a time-domain distributed optical signal Lt (xy) ;

[0022] 7) The fast photodetector receives the time-domain distributed optical signal Lt converted in step 6). (xy) And the time-domain distributed optical signal Lt (xy) Converted into electrical pulse signal Vt (xy) ;

[0023] 8) The digital oscilloscope receives the electrical pulse signal Vt from step 7). (xy) It outputs digital files to data analysis and processing computers;

[0024] 9) Adjust the height of the Z-axis uniform motion guide along the Z-axis direction, and repeat steps 3) to 8) to obtain a series of instantaneous morphologies Vxyz along the Z-axis direction. i ;

[0025] 10) Through data analysis and processing, the computer analyzes the Vxyz values ​​of the (i+1)th layer. i+1 and the i-th layer Vxyz i The XY coordinates are compared in real time and the larger value is taken. The maximum value Vxyz is obtained by iteratively obtaining the maximum value. max For Vxyz max Calibration is performed at the gradient inflection points of adjacent and temporal intervals to eliminate the influence of diffraction on the measurement results and obtain F. xyz As the morphological data of the workpiece, the feature values ​​of the three-dimensional morphology are described based on the morphological data of the workpiece, and the image of the three-dimensional morphology of the workpiece is reproduced.

[0026] The advantages of this invention are:

[0027] This invention provides a measurement device and method for three-dimensional micro / nano topography scanning and detection. The measurement device includes a white light interferometer, an imaging objective, a spatiotemporal scanning assembly, and a data analysis and processing computer. The white light interferometer, imaging objective, and spatiotemporal scanning assembly are arranged sequentially from front to back. The workpiece to be measured, the imaging objective, and the spatiotemporal scanning assembly are also arranged sequentially from front to back. The spatiotemporal scanning assembly is connected to the data analysis and processing computer. This invention uses a spatiotemporal scanning assembly to convert a two-dimensional image plane into a one-dimensional time-series signal, reducing the magnification requirements of the imaging system. Simultaneously, by utilizing high-bandwidth oscilloscope detection technology, the detection speed is greatly improved, overcoming the spatial size limitations of area array detectors. This invention uses a semiconductor pulsed laser to excite an upconversion plate, emitting dual-wavelength fluorescence. The radiation power is stable, and the correction model features are simple and clear, solving the problems of imaging distortion introduced by light wavelength and cumbersome correction data models in the measurement of complex micro / nano topography using existing white light interferometers. Attached Figure Description

[0028] Figure 1 This is a simplified structural diagram of the measuring device used in the present invention for three-dimensional micro-nano topography scanning and detection;

[0029] Figure 2 The present invention uses the image of the object's mirror surface, the pattern of the workpiece surface, and the electrical pulse signal Vt measured by the space-time scanning component. (xy) A simplified schematic diagram;

[0030] in:

[0031] 1-White light interferometer; 11-Semiconductor pulsed laser; 12-Upconverter; 13-Collimating lens; 14-Beam splitter; 15-Standard total reflection mirror; 2-Imaging objective lens; 3-Spacetime scanning assembly; 31-Spacetime scanner; 32-Fast photodetector. Detailed Implementation

[0032] This invention relates to the field of three-dimensional micro-nano topography detection, and in particular to the use of a fast unit detector to receive spatially delayed optical interference signals. By analyzing the spatial and temporal amplitude and frequency characteristics of the optical interference signals, the digital structure of the three-dimensional micro-nano topography of the workpiece surface is obtained, providing raw data for cloud map reproduction of the three-dimensional topography of the workpiece surface.

[0033] See Figure 1 The measuring device for three-dimensional micro / nano topography scanning and detection provided by this invention includes a white light interferometer 1, an imaging objective lens 2, a space-time scanning assembly 3, a Z-axis uniform motion guide rail, and a data analysis and processing computer. The imaging objective lens 2 images the standard reflected light from the white light interferometer 1 and the signal reflected light from the workpiece onto the receiving surface of the space-time scanner 3. The white light interferometer 1, the imaging objective lens 2, and the space-time scanning assembly 3 are fixedly mounted on the support platform of the Z-axis uniform motion guide rail, forming a three-dimensional scanning system. A digital oscilloscope receives the electrical pulse signal Vt output by the fast photodetector 32. (xy) The computer receives the digital files and performs data analysis and processing through data analysis and processing software. This software includes data acquisition software, real-time amplitude comparison software, hard boundary correction software, 3D morphology reproduction software, statistical analysis software, and storage software.

[0034] The white light interferometer 1 consists of a semiconductor pulsed laser 11, an upconversion plate 12, a collimating lens 13, a beam splitter 14, and a standard total reflection mirror 15. The upconversion plate 12 is made of rare-earth material Yb that can emit two wavelengths. 3+ / Ho 3+Made of double-doped fluorine-oxysilicate glass, it emits red light at 650nm and green light at 540nm when excited by a 980nm semiconductor pulsed laser 11. The interference fringe characteristics of the white light interferometer 1 operating at both wavelengths are beneficial for boundary signal identification, processing, and elimination during data processing. The collimating lens 13 is a lens that collimates both wavelengths simultaneously. The beam splitter 14 is a semi-reflective mirror and is placed at a 45° angle on the collimating optical path. The standard total reflection mirror 15 has a standard pattern on its reflecting surface, and the reflectivity of the standard pattern is greater than that of the substrate. It is vertically placed on the collimating optical path after the beam splitter 14. The semiconductor pulsed laser 11 emits pulsed laser light to irradiate the upconversion plate 12. Two wavelengths of light are excited. Collimating lens 13 converts the excited dual-wavelength light into collimated light. Beam splitter 14 splits the collimated light into two mutually perpendicular collimated beams. One beam illuminates the workpiece surface and forms the signal reflection light, while the other beam illuminates the standard total reflection mirror 15 and forms the standard reflection light. The standard reflection light carries information about the standard pattern. The signal reflection light is transmitted through beam splitter 14 and enters imaging objective 2. The standard reflection light is reflected by beam splitter 14 and enters imaging objective 2. Imaging objective 2 is a lens that simultaneously images the two wavelengths onto the same image plane. The image is formed and coherent on the image plane of imaging objective 2, and its image carries information about the surface morphology / standard pattern of the workpiece (e.g., ...). Figure 2 As shown, the instantaneous power of the coherent light is greater than the instantaneous power of the signal reflected light and the instantaneous power of the standard reflected light.

[0035] The space-time scanning component 3 comprises a space-time scanner 31, a fast photodetector 32, a digital oscilloscope, and data acquisition software. The space-time scanner 31 is made of an optical material that emits light through the upconversion plate 12, forming a spatial wedge shape. The overall shape is flat, and the refractive index n changes linearly with the plane position n(x', y'). Its thickness (delayed optical path) varies with different spatial positions, so that the workpiece pattern / standard pattern passing through the receiving surface of the space-time scanner 31 is delayed in a one-to-one correspondence. The spatial domain optical signal Pxy of the standard pattern of the standard total reflection mirror 15 and the instantaneous shape of the workpiece on the same object surface as the standard total reflection mirror 15 is converted into a time domain distributed optical signal Lt. (xy) The fast photodetector 32 is a unit photodetector, which is attached to another wedge-shaped surface of the space-time scanner 31 to receive the time-domain distributed optical signal Lt. (xy) Converted into an electrical pulse signal Vt (xy) The oscilloscope measures and records the electrical pulse signal Vt in real time. (xy) The data acquisition software performs real-time differential rejection of the electrical pulse signal Vt based on the dual-wavelength spectral characteristics and standard pattern characteristics of the white light interferometer 1. (xy) The instantaneous morphology Vxyz of the workpiece on the same surface as the standard total reflection mirror 15 was obtained. i .

[0036] The white light interferometer 1, imaging objective lens 2, and space-time scanning assembly 3 move at a constant speed along the Z-axis guide rail, thus achieving scanning of the workpiece in the Z-axis direction (Vxyz). i The scanning range in the Z-axis direction covers the depth of the workpiece in the Z-axis direction.

[0037] This invention provides a measurement method for three-dimensional micro / nano topography scanning and detection based on the measurement device for three-dimensional micro / nano topography scanning and detection as described above. The measurement method includes the following steps:

[0038] 1) Construct the measurement device for three-dimensional micro-nano topography scanning and detection as described above;

[0039] 2) Start the Z-axis uniform motion guide rail to drive the white light interferometer 1, imaging objective lens 2 and space-time scanning component 3 to move synchronously;

[0040] 3) After entering the Z-direction measurement range, record the Z-axis coordinate z. i At the same time, the white light interferometer 1 is turned on to emit pulsed laser light. After the pulsed laser light is incident on the upconversion plate 12, it forms two different wavelengths of fluorescence.

[0041] 4) Two different wavelengths of fluorescence are collimated by collimating lens 13 and then incident on beam splitter 14, and split into transmitted light and reflected light by beam splitter 14; the transmitted light after beam splitter 14 is reflected by standard total reflection mirror 15 to form standard reflected light; the reflected light after beam splitter 14 is reflected by the workpiece under test to form signal reflected light.

[0042] 5) The standard reflected light and the signal reflected light are respectively incident on the imaging objective lens 2 after passing through the beam splitter 14, and are imaged and coherent on the image plane of the imaging objective lens 2 to obtain a coherent image.

[0043] 6) After passing the coherence image obtained in step 5) through the space-time scanner 31, the instantaneous morphology spatial optical signal P of the workpiece is generated. xy Converted into a time-domain distributed optical signal Lt (xy) ;

[0044] 7) The fast photodetector 32 receives the time-domain distributed optical signal Lt converted in step 6). (xy) And the time-domain distributed optical signal Lt (xy) Converted into electrical pulse signal Vt (xy) ;

[0045] 8) The digital oscilloscope receives the electrical pulse signal Vt from step 7). (xy) It outputs digital files to data analysis and processing computers;

[0046] 9) Adjust the height of the Z-axis uniform motion guide along the Z-axis direction, and repeat steps 3) to 8) to obtain a series of instantaneous morphologies Vxyz along the Z-axis direction. i;

[0047] 10) Through data analysis and processing, the computer analyzes the Vxyz values ​​of the (i+1)th layer. i+1 and the i-th layer Vxyz i The XY coordinates are compared in real time and the larger value is taken. The maximum value Vxyz is obtained by iteratively obtaining the maximum value. max For Vxyz max Calibration is performed at the gradient inflection points of adjacent and temporal intervals to eliminate the influence of diffraction on the measurement results and obtain F. xyz As the morphological data of the workpiece, the feature values ​​of the three-dimensional morphology are described based on the morphological data, and the image of the three-dimensional morphology of the workpiece is reproduced. For example, the Vxyz values ​​of the (i+1)th layer are analyzed using real-time amplitude comparison software on a data analysis and processing computer. i+1 and the i-th layer Vxyz i The magnitudes of the corresponding X and Y coordinates are compared in real time, and the largest value Vxyz is obtained through iterative processing. max Take Vxyz in the Z-axis direction i The maximum amplitude of the XY coordinates corresponding to the coordinates Vxyz max As the morphological data of the workpiece, the hard boundary correction software uses a diffraction model to analyze Vxyz. max Calibration is performed at the gradient inflection points of adjacent and temporal intervals to eliminate the influence of diffraction on the measurement results, obtaining the morphology data Fxyz. The morphology data Fxyz is analyzed by statistical analysis software on a data analysis and processing computer, providing characteristic values ​​describing the 3D morphology, such as cylinder radius and depth. Storage software records the workpiece's morphology data Fxyz, characteristic values, and a reconstructed 3D morphology image. The 3D morphology reconstruction software on the data analysis and processing computer converts the measured data file into a 3D graphic, for example, CloudCompare_v2.11.3_bin_x64.

Claims

1. A measuring device for three-dimensional micro / nano topography scanning and detection, characterized in that: The measuring device for three-dimensional micro-nano topography scanning detection includes a white light interferometer (1), an imaging objective (2), a space-time scanning component (3), and a data analysis and processing computer; the white light interferometer (1), the imaging objective (2), and the space-time scanning component (3) are arranged sequentially from front to back; the workpiece to be measured, the imaging objective (2), and the space-time scanning component (3) are arranged sequentially from front to back; the space-time scanning component (3) is connected to the data analysis and processing computer.

2. The measuring device for three-dimensional micro / nano topography scanning and detection according to claim 1, characterized in that: The white light interferometer (1) includes a semiconductor pulsed laser (11), an upconversion plate (12), a collimating lens (13), a beam splitter (14), and a standard total reflection mirror (15); the semiconductor pulsed laser (11) emits pulsed laser light; the upconversion plate (12), the collimating lens (13), and the beam splitter (14) are arranged sequentially from front to back on the optical path of the pulsed laser light; the beam splitter (14) splits the laser light incident on the beam splitter (14) into transmitted light and reflected light; the standard total reflection mirror (15) is placed on the beam splitter. The transmitted light after beam splitter (14) is on the optical path; the transmitted light after beam splitter (14) is reflected by standard total reflection mirror (15) to form standard reflected light; the standard reflected light is incident on beam splitter (14) and reflected by beam splitter (14) to imaging objective (2); the workpiece to be tested is placed on the optical path of the reflected light after beam splitter (14); the reflected light after beam splitter (14) is reflected by the workpiece to be tested to form signal reflected light; the signal reflected light is incident on beam splitter (14) and transmitted by beam splitter (14) to imaging objective (2).

3. The measuring device for three-dimensional micro / nano topography scanning and detection according to claim 2, characterized in that: The upconversion plate (12) is made of rare earth material Yb that can excite two wavelengths. 3+ / Ho 3+ The material is made of double-doped fluorine-oxysilicate glass; the semiconductor pulsed laser (11) excites the upconversion plate (12) to emit red light at 650 nm and green light at 540 nm; the beam splitter (14) is a semi-reflective mirror; the standard total reflection mirror (15) includes a substrate and a standard pattern disposed on the substrate; the reflectivity of the standard pattern is greater than the reflectivity of the substrate.

4. The measuring device for three-dimensional micro / nano topography scanning and detection according to claim 3, characterized in that: The space-time scanning component (3) includes a space-time scanner (31), a fast photodetector (32), and a digital oscilloscope; the standard reflected light is incident on the fast photodetector (32) after passing through a beam splitter (14), an imaging objective (2), and the space-time scanner (31); the signal reflected light is incident on the fast photodetector (32) after passing through a beam splitter (14), an imaging objective (2), and the space-time scanner (31); the fast photodetector (32) is connected to a data analysis and processing computer via the digital oscilloscope.

5. The measuring device for three-dimensional micro / nano topography scanning and detection according to claim 4, characterized in that: The spacetime scanner (31) is wedge-shaped; the fast photodetector (32) is attached to the wedge-shaped surface of the spacetime scanner (31); the standard reflected light is incident on the fast photodetector (32) after passing through the beam splitter (14), the imaging objective (2) and the receiving surface of the spacetime scanner (31); the signal reflected light is incident on the fast photodetector (32) after passing through the beam splitter (14), the imaging objective (2) and the receiving surface of the spacetime scanner (31).

6. The measuring device for three-dimensional micro / nano topography scanning and detection according to claim 5, characterized in that: The material of the space-time scanner (31) is an optical material with a high refractive index that emits red light at 650 nm and green light at 540 nm from the upconversion plate (12).

7. The measuring device for three-dimensional micro / nano topography scanning and detection according to claim 6, characterized in that: The fast photodetector (32) is a unit photodetector.

8. The measuring device for three-dimensional micro / nano topography scanning and detection according to any one of claims 1-7, characterized in that: The measuring device for three-dimensional micro-nano topography scanning and detection also includes a Z-axis uniform motion guide rail; the white light interferometer (1), imaging objective (2) and space-time scanning component (3) are fixed together on the Z-axis uniform motion guide rail and move freely along the axial direction of the Z-axis uniform motion guide rail.

9. The measuring device for three-dimensional micro / nano topography scanning and detection according to claim 8, characterized in that: The data analysis and processing computer includes, in sequence from front to back, a data acquisition module, a real-time amplitude comparison module, a hard boundary correction module, a three-dimensional shape reproduction module, a statistical analysis module, and a storage module.

10. A measurement method for three-dimensional micro / nano topography scanning detection based on the measurement device for three-dimensional micro / nano topography scanning detection as described in claim 9, characterized in that: The measurement method includes the following steps: 1) Construct the measurement device for three-dimensional micro / nano topography scanning and detection as described in claim 9; 2) Start the Z-axis uniform motion guide rail to drive the white light interferometer (1), imaging objective (2) and space-time scanning component (3) to move synchronously; 3) After entering the Z-direction measurement range, record the Z-axis coordinate z. i At the same time, the white light interferometer (1) is turned on to emit pulsed laser light, and the pulsed laser light is incident on the upconversion plate (12) to form two different wavelengths of fluorescence. 4) Two different wavelengths of fluorescence are collimated by a collimating lens (13) and then incident on a beam splitter (14), which splits them into transmitted light and reflected light. The transmitted light after passing through the beam splitter (14) is reflected by a standard total reflection mirror (15) to form standard reflected light. The reflected light after passing through the beam splitter (14) is reflected by the workpiece under test to form signal reflected light. 5) The standard reflected light and the signal reflected light are respectively passed through the beam splitter (14) and then incident on the imaging objective (2) and imaged and coherently on the image plane of the imaging objective (2) to obtain a coherent image; 6) After passing the coherence image obtained in step 5) through the space-time scanner (31), the instantaneous morphology spatial optical signal P of the workpiece is generated. xy Converted into a time-domain distributed optical signal Lt (xy) ; 7) The fast photodetector (32) receives the time-domain distributed optical signal Lt converted in step 6). (xy) And the time-domain distributed optical signal Lt (xy) Converted into electrical pulse signal Vt (xy) ; 8) The digital oscilloscope receives the electrical pulse signal Vt from step 7). (xy) It outputs digital files to data analysis and processing computers; 9) Adjust the height of the Z-axis uniform motion guide along the Z-axis direction, and repeat steps 3) to 8) to obtain a series of instantaneous morphologies Vxyz along the Z-axis direction. i ; 10) Through data analysis and processing, the computer analyzes the Vxyz values ​​of the (i+1)th layer. i+1 and the i-th layer Vxyz i The XY coordinates are compared in real time and the larger value is taken. The maximum value Vxyz is obtained by iteratively obtaining the maximum value. max , for Vxyz max Calibration is performed at the gradient inflection points of adjacent and temporal intervals to eliminate the influence of diffraction on the measurement results and obtain F. xyz As the morphological data of the workpiece, the feature values ​​of the three-dimensional morphology are described based on the morphological data of the workpiece, and the image of the three-dimensional morphology of the workpiece is reproduced.

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