Spectral confocal three-dimensional topography restoration method and system based on metasurface spectral imaging chip

Abstract

The present disclosure relates to a spectral confocal three-dimensional topography restoration method and system based on a metasurface spectral imaging chip. The method comprises: a continuous spectrum light source device emitting a continuous spectrum light beam to a dispersive objective lens, the continuous spectrum light beam being irradiated to the surface of an object to be measured after being spatially separated along the optical axis direction by the dispersive objective lens, and reflection occurring on the surface of the object; part of the reflected light beam irradiates the focusing lens after passing through the light transmission hole of the light shielding plate, and is incident on the metasurface spectral imaging chip after being focused by the focusing lens; the wavelength information collected by the metasurface spectral imaging chip is converted into height information, and the three-dimensional topography of the object surface is fitted according to the height information and the pixel position corresponding to the height information. The present disclosure realizes the restoration of the three-dimensional topography by a simple optical system once, and has high efficiency and low cost.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of three-dimensional topography reconstruction, and in particular to a spectral confocal three-dimensional topography reconstruction method and system based on a metasurface spectral imaging chip. BACKGROUND

[0002] In the high-precision fields of semiconductor wafer processing, aerospace, etc., the characterization of the micro-topography and defects on the surface of an object is an important part of detection. The detection of macroscopic defects based on traditional visual images has certain self-controllable risks for mesoscopic defect detection equipment with sizes between macroscopic and microscopic.

[0003] Currently widely used 3D topography imaging instruments include white light interferometers, laser confocal microscopes, etc. Such devices are high-precision scientific instruments, but have high costs. In industry, line laser profilers are often used. Such devices have low costs, but low precision, with a z-direction resolution of only about 0.2 mm. Spectral confocal displacement sensors can only detect a single point and are often used for precise distance testing and focusing of high-magnification imaging systems. There is also a scheme combining spectral confocal technology and line-scan spectral cameras to realize three-dimensional topography characterization. However, due to the line-scan architecture, a certain amount of time is required for scanning, which is a "time-for-space" trade-off and has certain limitations in efficiency. Therefore, there is a need to develop a spectral confocal three-dimensional topography reconstruction method and system with low cost and high efficiency. SUMMARY

[0004] Therefore, it is necessary to provide a spectral confocal three-dimensional topography reconstruction method and system based on a metasurface spectral imaging chip to solve the problems of high cost and low efficiency.

[0005] To solve the above problems, the present disclosure adopts the following technical solutions:

[0006] In a first aspect, the present disclosure provides a spectral confocal three-dimensional topography reconstruction method based on a metasurface spectral imaging chip, comprising the following steps:

[0007] A continuous spectrum light source device emits a continuous spectrum light beam to a dispersive objective lens. After the continuous spectrum light beam is spatially separated along the optical axis direction by the dispersive objective lens, it irradiates the surface of an object to be measured three-dimensional topography, and reflection occurs on the surface of the object;

[0008] Part of the reflected light beam irradiates the focusing lens after passing through the light transmission hole of the light shielding plate, and is focused onto the metasurface spectral imaging chip by the focusing lens. The metasurface spectral imaging chip collects wavelength information;

[0009] The wavelength information collected by the metasurface spectral imaging chip is converted into height information. According to the height information and the pixel position corresponding to the height information, the three-dimensional topography of the surface of the object is fitted.

[0010] In a preferred embodiment, the continuous spectrum light source device is a point light source.

[0011] In a preferred embodiment, the continuous spectrum light source device is a halogen lamp, and the dispersive objective lens is a high chromatic aberration dispersive objective lens.

[0012] In a preferred embodiment, the light shield is used to pass part or all of the light that can be focused by the focusing lens.

[0013] In a preferred embodiment, the wavelength information collected by the metasurface spectral imaging chip is converted into height information, and the three-dimensional topography of the object surface is fitted according to the height information and the pixel position corresponding to the height information.

[0014] The wavelength information collected by the metasurface spectral imaging chip is two-dimensional spatially distributed wavelength information.

[0015] The two-dimensional spatially distributed wavelength information is converted into height information, and the three-dimensional topography of the object surface is fitted according to the height information and the pixel position corresponding to the height information.

[0016] The two-dimensional spatially distributed wavelength information is converted into height information by mapping and contrasting the metasurface spectral imaging chip calibration and the three-dimensional height of the object.

[0017] The height values of the height information are fitted according to the pixel position corresponding to the height information, so as to restore the three-dimensional topography of the object surface.

[0018] In a second aspect, the present disclosure provides a spectral confocal three-dimensional topography restoration system based on a metasurface spectral imaging chip, comprising:

[0019] A continuous spectrum light source device for emitting a continuous spectrum light beam;

[0020] A dispersive objective lens for realizing spatial separation of the continuous spectrum light beam emitted by the continuous spectrum light source device along the optical axis direction, and the spatially separated light is used to irradiate the object surface of the three-dimensional topography to be measured;

[0021] A light shield for passing part of the reflected light beam through the light transmission hole of the light shield;

[0022] A focusing lens for focusing the light beam passing through the light transmission hole;

[0023] A metasurface spectral imaging chip for collecting wavelength information of the light beam focused by the focusing lens;

[0024] A fitting module for converting the wavelength information collected by the metasurface spectral imaging chip into height information, and for fitting the three-dimensional topography of the object surface according to the height information and the pixel position corresponding to the height information.

[0025] In a preferred embodiment, the continuous spectrum light source device is a point light source.

[0026] In a preferred embodiment, the continuous spectrum light source device is a halogen lamp, and the dispersive objective is a high chromatic aberration dispersive objective.

[0027] In a preferred embodiment, the light transmission hole for transmitting part of the reflected light beam through the light blocking plate is specifically for transmitting part or all of the light that can be focused by the focusing lens.

[0028] In a preferred embodiment, the fitting module is specifically used for converting the wavelength information distributed in two-dimensional space into height information, fitting the three-dimensional topography of the object surface according to the height information and the pixel position corresponding to the height information, converting the wavelength information distributed in two-dimensional space into height information by mapping and contrasting the three-dimensional height of the object with the calibration of the metasurface spectral imaging chip, and fitting the height value of the height information according to the pixel position corresponding to the height information to restore the three-dimensional topography of the object surface.

[0029] The above-mentioned spectral confocal three-dimensional topography restoration method and system based on the metasurface spectral imaging chip, by means of the continuous spectrum light source device emitting a continuous spectrum light beam, the dispersive objective performing spatial separation of the light beam along the optical axis direction, the selective transmission of the light blocking plate, the focusing of the focusing lens, the wavelength information collected by the metasurface spectral imaging chip, the wavelength information converted into height information, and the three-dimensional topography of the object surface fitted. By such design, the present disclosure realizes the restoration of the three-dimensional topography by one-time shooting through a simple optical system, greatly reduces the time required for topography restoration, improves the efficiency of topography restoration, and realizes the restoration at a low cost. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 It is a flowchart of the three-dimensional topography restoration method of the present disclosure;

[0031] Figure 2 It is a realization schematic diagram of the present disclosure;

[0032] Figure 3 It is a point light source imaging effect schematic diagram of wavelength λ1 under the same object distance of the present disclosure;

[0033] Figure 4 It is a point light source imaging effect schematic diagram of wavelength λ2 under the same object distance of the present disclosure;

[0034] Figure 5 It is a point light source imaging effect schematic diagram of wavelength λ3 under the same object distance of the present disclosure;

[0035] Figure 6 It is a point light source imaging effect schematic diagram of wavelength λ4 under the same object distance of the present disclosure;

[0036] Figure 7 Point light source imaging effect schematic diagram of wavelength λ5 under the same object distance of the disclosure;

[0037] Figure 8 Point light source imaging effect schematic diagram of wavelength λ6 under the same object distance of the disclosure;

[0038] Figure 9 Point light source imaging effect schematic diagram of wavelength λ7 under the same object distance of the disclosure;

[0039] Figure 10 Point light source imaging effect schematic diagram of wavelength λ8 under the same object distance of the disclosure;

[0040] Figure 11 Point light source imaging effect schematic diagram of wavelength λ9 under the same object distance of the disclosure;

[0041] Figure 12 Actual object diagram of the object;

[0042] Figure 13 Schematic diagram of the three-dimensional topography of the object restored;

[0043] Wherein, 1, halogen lamp; 2, dispersive objective lens; 3, light shield plate; 4, focusing lens; 5, metasurface spectral imaging chip. DETAILED DESCRIPTION

[0044] The technical solutions of the disclosure will be described in detail below with reference to the preferred embodiments and the accompanying drawings.

[0045] Referring to the flowchart of Figure 1 and the optical path schematic diagram of Figure 2 The disclosure provides a spectral confocal three-dimensional topography restoration method based on a metasurface spectral imaging chip, comprising:

[0046] The continuous spectrum light source device emits a continuous spectrum light beam to the dispersive objective lens 2, and the continuous spectrum light beam is irradiated to the surface of the object to be measured after being spatially separated along the optical axis direction by the dispersive objective lens 2, and reflection occurs on the surface of the object;

[0047] Part of the reflected light beam is irradiated to the focusing lens 4 after passing through the light transmission hole of the light shield plate 3, and is focused on the metasurface spectral imaging chip 5 by the focusing lens 4. The wavelength information collected by the metasurface spectral imaging chip 5;

[0048] The wavelength information collected by the metasurface spectral imaging chip 5 is converted into height information, and the three-dimensional topography of the object surface is fitted according to the height information and the pixel position corresponding to the height information.

[0049] Specifically, the method specifically comprises the following steps:

[0050] Step 1, the continuous spectrum light source device adopts a point light source, specifically a halogen lamp 1, the halogen lamp 1 emits a light beam to a dispersion objective 2, the light beam passes through the dispersion objective 2, and the dispersion objective 2 is used to separate the complex light according to the z-direction space by using the chromatic aberration characteristics of the dispersion objective 2, and the spatially separated light beam irradiates the surface of the object to be measured three-dimensional topography, and reflection occurs on the surface of the object.

[0051] It can be understood that, due to the chromatic aberration property of the dispersion objective 2 itself, light of different wavelengths will be focused at different focal planes, for example, light of wavelength λ1 will be focused at a height of h1, and light of wavelength λ2 will be focused at a height of h2.

[0052] Step 2, collecting reflected light information: the different wavelengths of light after reflection pass through the light transmission hole for wavelength screening, and other stray light except the light that can be focused by the focusing lens 4 is filtered out, and only the target wavelength light is collected into the focusing lens 4.

[0053] Part of the light beam reflected by the surface of the object to be measured three-dimensional topography transmits to the focusing lens 4 through the light transmission hole, and the other part does not transmit to the focusing lens 4, that is, it is blocked. That is, the light shield 3 has a light transmission hole, and the different wavelengths of light after reflection pass through the light transmission hole for wavelength screening, and part or all of the light beam that can be focused by the focusing lens 4 is transmitted, and other stray light is filtered out. The wavelength light beam that can be focused is screened through the light transmission hole.

[0054] Step 3, the focusing lens 4 focuses the light beam to the super surface spectral imaging chip 5, and the super surface spectral imaging chip 5 collects the spectral information according to the two-dimensional spatial distribution, that is, each pixel collects independent wavelength information;

[0055] It can be understood that the super surface spectral imaging chip 5, also known as a super surface chip, a super surface light chip, a super surface spectral chip, and a super surface optical chip, is a miniature spectral imaging device based on super surface technology, which realizes spectral modulation of light through a subwavelength micro-nano structure array, and combines a CMOS image sensor and a calculation reconstruction algorithm to quickly obtain a high-resolution spectral image.

[0056] Step 4, the collected wavelength information (two-dimensional spatial distribution of wavelength information) is mapped and compared with the three-dimensional height of the object by the super surface spectral imaging chip 5, the wavelength information in the two-dimensional spatial distribution is converted into height information, and then the height information is fitted according to the pixel position corresponding to the height information, so that the complete three-dimensional topography is obtained.

[0057] It can be understood that the height information includes a height value, and does not limit what data the height information includes.

[0058] In the process of fitting the three-dimensional morphology of the object surface, the defocus blur of the chromatic objective lens needs to be calculated. The present disclosure is to collect different waveband images at the same distance. For the same light source, the imaging spot diameters of different wavebands are different at the same distance, that is, the defocus blur is different. According to the calibration algorithm, the blur spot diameters of the spectral images of each waveband are calculated, and the curve of the blur spot diameters of each waveband changing with distance is obtained, which reflects the dispersion variation law of the chromatic objective lens of each waveband within a certain distance range. Figures 3 to 11 An example of imaging effect of a point light source of the same object distance and different wavebands (wavelength λ1 to wavelength λ9).

[0059] The present disclosure also provides a spectral confocal three-dimensional morphology restoration system based on a metasurface spectral imaging chip, which comprises:

[0060] A continuous spectrum light source device for emitting a continuous spectrum light beam;

[0061] A chromatic objective lens 2 for realizing spatial separation of the continuous spectrum light beam emitted by the continuous spectrum light source device along the optical axis direction, and the spatially separated light is used to irradiate the surface of the object to be measured three-dimensional morphology;

[0062] An optical barrier 3 for passing part of the reflected light beam through the light transmission hole of the optical barrier 3;

[0063] A focusing lens 4 for focusing the light beam passing through the light transmission hole;

[0064] A metasurface spectral imaging chip 5 for collecting wavelength information of the light beam focused by the focusing lens 4;

[0065] A fitting module for converting the wavelength information collected by the metasurface spectral imaging chip 5 into height information, and fitting the three-dimensional morphology of the object surface according to the height information and the pixel position corresponding to the height information.

[0066] In the present embodiment, the optical barrier 3 is specifically used to pass part or all of the light that can be focused by the focusing lens 4 through the light transmission hole (in the reflected light beam of the object surface).

[0067] It can be understood that the wavelength information collected by the metasurface spectral imaging chip 5 is two-dimensional spatially distributed wavelength information.

[0068] In the present embodiment, the fitting module is specifically used to:

[0069] The wavelength information distributed in two-dimensional space is converted into height information, and the three-dimensional morphology of the object surface is fitted according to the height information and the pixel position corresponding to the height information; the wavelength information distributed in two-dimensional space is converted into height information by mapping and contrasting the three-dimensional height of the object through the hypersurface spectral imaging chip 5; and the height value of the height information is fitted according to the pixel position corresponding to the height information, so as to restore the three-dimensional morphology of the object surface.

[0070] Figure 12 An actual object of an object is shown in the figure, and the letter "CUST" in the figure is a convex. Figure 13 The three-dimensional morphology restored by applying the method and system of the present disclosure to the object, Figure 13 The gradual color bar in the figure represents the height of CUST (CUST is a letter in the plane where it is located), and the unit is nanometer.

[0071] The hypersurface spectral imaging chip-based spectral confocal three-dimensional morphology restoration method and system of the present disclosure can realize the restoration of the morphology information of the target region of the object surface in one shot of the hypersurface spectral imaging chip 5. Compared with the point-by-point scanning mode of the traditional single-point spectral confocal displacement sensor and the line-scan spectral confocal sensor, the hypersurface spectral imaging chip-based spectral confocal three-dimensional morphology restoration method and system of the present disclosure reduces the need for multiple scans and data processing, thereby greatly reducing the time required for morphology restoration and improving the efficiency of morphology restoration. Through the hypersurface spectral imaging chip 5, in combination with the continuous spectrum light source device, the dispersive objective lens 2, the light shield 3, and the focusing lens 4, the spectral information can be accurately combined with the height information of the target. Different wavelengths of light can represent different object heights and provide high-resolution three-dimensional morphology data, making the imaging result more accurate and reliable.

[0072] The present disclosure has a wide range of applications: the application of the technology is no longer limited to specific objects or environments, and its high efficiency and accuracy make it applicable to various industries, including manufacturing, environmental monitoring, biomedicine, etc. Whether in a complex industrial environment or in a laboratory condition, it can provide high-quality imaging results.

[0073] In the present disclosure, the design of the optical system is simplified by using the hypersurface spectral imaging chip 5 and the like, and the dependence on complex mechanical scanning mechanisms is reduced. This simplification not only reduces the manufacturing cost, but also improves the overall reliability and stability.

[0074] In the present disclosure, the continuous spectrum light source device (halogen lamp 1) and the dispersive objective lens 2 constitute a spectral confocal illumination system, which has spatial dispersion capability and realizes effective separation and focusing of polychromatic light through chromatic aberration principle. The dispersive objective lens 2 adopts a high chromatic aberration dispersive objective lens. In the present embodiment, the dispersive objective lens 2 with a chromatic aberration value ΔE > 2.0 is referred to as a high chromatic aberration dispersive objective lens.

[0075] The spectral imaging system structure of the metasurface spectral imaging chip 5 in the spectral imaging system of the metasurface in the present disclosure comprises a light shielding plate 3, a focusing lens 4 and a metasurface spectral imaging chip 5, and can design lens parameters according to different scene requirements to optimize the imaging effect.

[0076] The present disclosure can perform spectral imaging on objects in a certain area range in one shot, express the height parameter in the z direction by using spectral characteristics, and realize efficient three-dimensional imaging by combining two-dimensional spatial resolution.

[0077] The metasurface spectral chip of the present disclosure utilizes the metasurface technology in micro-nano optics, realizes selective transmission of different wavelengths of light through the surface plasmon and localized surface plasmon effect generated by the periodic microstructure, and has similar functions to color filters, but has higher flexibility and adjustability. The characteristic peak position and transmission spectrum of the metasurface spectral chip can be flexibly adjusted by adjusting the period parameters of the microstructure to meet the demand for spectral response in different application scenarios.

[0078] The composite architecture of the present disclosure realizes efficient integration of the illumination system and the imaging system, optimizes the performance of the entire optical system, and improves the application range and practicality of the three-dimensional imaging technology.

[0079] The technical features of the above-described embodiments can be combined arbitrarily, and to make the description concise, not all possible combinations of the technical features in the above-described embodiments are described, however, as long as the combinations of the technical features do not exist contradictory, they should be considered as the scope of the present disclosure.

[0080] The above-described embodiments only express several implementation manners of the present disclosure, the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present disclosure, a number of modifications and improvements can be made, which are all within the protection scope of the present disclosure. Therefore, the protection scope of the patent of the present disclosure should be subject to the appended claims.

Claims

1. A spectral confocal three-dimensional topography restoration method based on a metasurface spectral imaging chip, characterized in that, The method comprises the following steps: The continuous spectrum light source device emits a continuous spectrum light beam to a dispersive objective lens, the continuous spectrum light beam is spatially separated along the optical axis direction after passing through the dispersive objective lens, and then irradiates the surface of an object with a three-dimensional topography to be measured, and reflection occurs on the surface of the object; Part of the reflected light beam passes through the light transmission hole of the light shielding plate and then irradiates the focusing lens, and then is focused by the focusing lens onto the metasurface spectral imaging chip, and the metasurface spectral imaging chip collects wavelength information; The wavelength information collected by the metasurface spectral imaging chip is converted into height information, and the three-dimensional topography of the object surface is fitted according to the height information and the pixel position corresponding to the height information; The wavelength information collected by the metasurface spectral imaging chip is converted into height information, and the three-dimensional topography of the object surface is fitted according to the height information and the pixel position corresponding to the height information; The wavelength information collected by the metasurface spectral imaging chip is two-dimensional spatially distributed wavelength information; The two-dimensional spatially distributed wavelength information is converted into height information, and the three-dimensional topography of the object surface is fitted according to the height information and the pixel position corresponding to the height information; The two-dimensional spatially distributed wavelength information is converted into height information by mapping and comparing the calibration of the metasurface spectral imaging chip and the three-dimensional height of the object; According to the pixel position corresponding to the height information, the height value of the height information is fitted, so as to restore the three-dimensional topography of the object surface.

2. The metasurface-based spectral imaging chip method for spectral confocal three-dimensional topography reconstruction according to claim 1, characterized in that, The continuous spectrum light source device is a point light source.

3. The metasurface-based spectral imaging chip method for spectral confocal three-dimensional topography reconstruction according to claim 2, characterized in that, The continuous spectrum light source device is a halogen lamp, and the dispersive objective lens adopts a high chromatic aberration dispersive objective lens.

4. The metasurface-based spectral imaging chip method of spectral confocal three- dimensional topography reconstruction according to claim 1, characterized in that, The light shielding plate is used to transmit part or all of the light that can be focused by the focusing lens.

5. A spectral confocal three-dimensional topography reconstruction system based on a metasurface spectral imaging chip, characterized in that, The system comprises: A continuous spectrum light source device is configured to emit a continuous spectrum light beam; A dispersive objective lens is configured to spatially separate the continuous spectrum light beam emitted by the continuous spectrum light source device along the optical axis direction, and the spatially separated light beam is configured to irradiate the surface of an object with a three-dimensional topography to be measured; A light shielding plate is configured to pass part of the reflected light beam through the light transmission hole of the light shielding plate; A focusing lens is configured to focus the light beam passing through the light transmission hole; A metasurface spectral imaging chip is configured to collect wavelength information of the light beam focused by the focusing lens; A fitting module is configured to convert the wavelength information collected by the metasurface spectral imaging chip into height information, and to fit the three-dimensional topography of the object surface according to the height information and the pixel position corresponding to the height information; the fitting module is specifically configured to convert two-dimensional spatially distributed wavelength information into height information, and to fit the three-dimensional topography of the object surface according to the height information and the pixel position corresponding to the height information; the fitting module is configured to convert the two-dimensional spatially distributed wavelength information into height information by mapping and comparing the calibration of the metasurface spectral imaging chip and the three-dimensional height of the object; and the fitting module is configured to fit the height value of the height information according to the pixel position corresponding to the height information, so as to restore the three-dimensional topography of the object surface.

6. The metasurface-based spectral imaging chip system for spectral confocal three-dimensional topography reconstruction according to claim 5, wherein, The continuous spectrum light source device is a point light source.

7. The metasurface-based spectral imaging chip system for spectral confocal three-dimensional topography reconstruction according to claim 6, wherein, The continuous spectrum light source device is a halogen lamp, and the dispersive objective lens adopts a high chromatic aberration dispersive objective lens.

8. The metasurface-based spectral imaging chip system for spectral confocal three-dimensional topography reconstruction according to claim 5, wherein, The light shielding plate is configured to transmit part or all of the light that can be focused by the focusing lens.

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