WO2024050677A1 - 红外微测辐射热计探测器及其设计方法、制造方法和*** - Google Patents

红外微测辐射热计探测器及其设计方法、制造方法和*** Download PDF

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WO2024050677A1
WO2024050677A1 PCT/CN2022/117137 CN2022117137W WO2024050677A1 WO 2024050677 A1 WO2024050677 A1 WO 2024050677A1 CN 2022117137 W CN2022117137 W CN 2022117137W WO 2024050677 A1 WO2024050677 A1 WO 2024050677A1
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pixel
metasurface
level
layer
infrared
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PCT/CN2022/117137
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English (en)
French (fr)
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黄东琪
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黄东琪
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Priority to PCT/CN2022/117137 priority Critical patent/WO2024050677A1/zh
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
    • G01J5/02—Constructional details
    • G01J5/08—Optical arrangements
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
    • G01J5/10—Radiation pyrometry, e.g. infrared or optical thermometry using electric radiation detectors
    • G01J5/20—Radiation pyrometry, e.g. infrared or optical thermometry using electric radiation detectors using resistors, thermistors or semiconductors sensitive to radiation, e.g. photoconductive devices

Definitions

  • the invention relates to the field of infrared detection, and in particular to an infrared microbolometer detector, its design method, manufacturing method and an infrared microbolometer system.
  • color infrared thermal imaging technology has become a new research hotspot.
  • Traditional infrared thermal imaging technology means that the infrared light radiated by the object to be measured is focused through the lens and received by the infrared focal plane detector, and finally presents a grayscale monochromatic infrared image.
  • the gray-scale monochromatic infrared image presents the result of the interaction of incident light in a wide band.
  • the infrared focal plane detectors such as a microbolometer (bolometer)
  • the gray-scale image presented Usually contains all information of long-wave infrared light in the 8 to 14 micron (um) band.
  • infrared focal plane detectors Since gray-scale monochromatic infrared images present the result of the interaction of incident light in a wide band and contain very limited detailed information, a key technology for the new generation of infrared focal plane detectors is to separate infrared light of different wavelengths. And illuminated on different pixels to achieve multi-spectral imaging or multi-polarization imaging, and form a color infrared image through RGB rendering.
  • the existing infrared focal plane detectors that can achieve color are mainly refrigerated detectors based on mercury cadmium telluride materials. Detectors based on mercury cadmium telluride can often only distinguish between short-wave infrared, medium-wave infrared, and long-wave infrared. band, it is difficult to distinguish finer spectral segments. It cannot meet the demand for more detailed infrared images.
  • the purpose of this application is to provide an infrared microbolometer detector and its design method and manufacturing method.
  • the infrared microbolometer detector can distinguish finer spectral segments and detect the obtained infrared image. Can have higher precision.
  • the embodiment of the present application provides an infrared microbolometer detector, including:
  • a pixel-level metasurface layer is provided on the side of the microbolometer micro-electromechanical system structure away from the first substrate;
  • the pixel-level metasurface layer includes a plurality of pixel-level metasurface minimum units, and the size M of the pixel-level metasurface minimum unit satisfies the following conditions:
  • the ⁇ is the wavelength of the incident light
  • the n meta is the refractive index of the pixel-level metasurface layer.
  • the embodiment of the present application provides a design method for an infrared microbolometer detector, including:
  • the first heuristic function represents the imaging effect of the pixel-level metasurface unit.
  • the pixel-level metasurface unit The unit includes multiple pixel-level metasurface minimal units;
  • Embodiments of the present application provide a method for manufacturing an infrared microbolometer detector, including:
  • a pixel-level metasurface layer is formed on the side of the microbolometer MEMS structure away from the first substrate.
  • the pixel-level metasurface layer includes a plurality of pixel-level metasurface minimal units.
  • the size M of the smallest unit of the metasurface satisfies the following conditions:
  • the ⁇ is the wavelength of the incident light
  • the n meta is the refractive index of the pixel-level metasurface layer.
  • the embodiment of the present application provides an infrared microbolometer system, which is characterized in that it includes an infrared lens, a shutter film, and the infrared microbolometer detector described in any one of the above embodiments.
  • Embodiments of the present application provide an infrared microbolometer detector, which is characterized in that it includes: a first substrate, a detector readout circuit and a microbolometer sensor arranged sequentially on one side of the first substrate.
  • the electromechanical system structure and the pixel-level metasurface layer are arranged on the side of the microbolometer micro-electromechanical system structure away from the first substrate.
  • the pixel-level metasurface layer includes a plurality of pixel-level metasurface minimum units, and the pixel-level metasurface is the smallest unit.
  • the size M of the unit satisfies the following conditions:
  • ⁇ is the wavelength of incident light
  • n meta is the refractive index of the pixel-level metasurface layer.
  • the pixel-level metasurface layer provided by the embodiments of the present application includes multiple pixel-level metasurface minimum units. The size of each pixel-level metasurface minimum unit is smaller than the wavelength of the incident light. It can achieve fine distinction of the incident light, and the differentiated The incident light is concentrated into a specific microbolometer microelectromechanical system structure so that the detector readout circuit can read it and ultimately obtain a more detailed infrared image.
  • Figure 1 shows a schematic diagram of a refrigerated detector based on mercury cadmium telluride material
  • Figure 2 shows a schematic cross-sectional structural diagram of an infrared microbolometer detector provided by an embodiment of the present application
  • Figure 3 shows a side cross-sectional view of an infrared microbolometer detector provided by an embodiment of the present application
  • Figure 4 shows a partial structural schematic diagram of an infrared microbolometer detector provided by an embodiment of the present application
  • Figure 5 shows a schematic diagram of equivalent pixels of a detector provided by an embodiment of the present application
  • Figure 6 shows a partial structural schematic diagram of another infrared microbolometer detector provided by an embodiment of the present application.
  • Figure 7 shows a schematic partial structural diagram of a pixel-level metasurface layer provided by an embodiment of the present application.
  • Figure 8 shows a schematic diagram of the partial structure of various pixel-level metasurface minimum units provided by embodiments of the present application.
  • Figure 9(a) shows a graphical schematic diagram of a pixel-level metasurface layer provided by an embodiment of the present application.
  • Figure 9(b) shows a graphical schematic diagram of another pixel-level metasurface layer provided by an embodiment of the present application.
  • Figure 10(a) shows a functional schematic diagram of an infrared microbolometer detector provided by an embodiment of the present application
  • Figure 10(b) shows a functional schematic diagram of another infrared microbolometer detector provided by an embodiment of the present application.
  • Figure 10(c) shows a functional schematic diagram of yet another infrared microbolometer detector provided by an embodiment of the present application.
  • Figure 10(d) shows a functional schematic diagram of yet another infrared microbolometer detector provided by an embodiment of the present application.
  • Figure 11 shows a partial structural diagram of the infrared microbolometer detector shown in Figure 10;
  • Figure 12 shows a schematic cross-sectional structural diagram of another infrared microbolometer detector provided by an embodiment of the present application.
  • Figure 13 shows a bonding schematic diagram of an infrared microbolometer detector provided by an embodiment of the present application
  • Figure 14 shows a flow chart of a design method for an infrared microbolometer detector provided by an embodiment of the present application
  • Figure 15 shows a flow chart of another design method for an infrared microbolometer detector provided by an embodiment of the present application.
  • Figure 16(a) shows a rendering of the manufacturing process of an infrared microbolometer detector provided by an embodiment of the present application
  • Figure 16(b) shows a rendering of the manufacturing process of another infrared microbolometer detector provided by the embodiment of the present application.
  • Figure 16(c) shows a rendering of the manufacturing process of yet another infrared microbolometer detector provided by the embodiment of the present application.
  • Figure 17(a) shows a simulation diagram of an infrared microbolometer detector provided by an embodiment of the present application
  • Figure 17(b) shows the simulation rendering of Figure 17(a);
  • Figure 18 shows a flow chart of a manufacturing method of an infrared microbolometer detector provided by an embodiment of the present application
  • Figure 19 shows a flow chart of a method for manufacturing a pixel-level metasurface layer provided by an embodiment of the present application
  • Figure 20 shows a flow chart of another method for manufacturing a pixel-level metasurface layer provided by an embodiment of the present application
  • Figure 21 shows a flow chart of yet another method for manufacturing a pixel-level metasurface layer provided by an embodiment of the present application
  • Figure 22 shows a schematic structural diagram of an infrared microbolometer system provided by an embodiment of the present application.
  • color infrared thermal imaging technology has become a new research hotspot.
  • Traditional infrared thermal imaging technology means that the infrared light radiated by the object to be measured is focused through the lens and received by the infrared focal plane detector, and finally presents a grayscale monochromatic infrared image.
  • the gray-scale monochromatic infrared image presents the result of the interaction of incident light in a wide band.
  • the infrared focal plane detectors such as a microbolometer (bolometer)
  • the gray-scale image presented Usually contains all information of long-wave infrared light in the 8 to 14 micron (um) band.
  • infrared focal plane detectors Since gray-scale monochromatic infrared images present the result of the interaction of incident light in a wide band and contain very limited detailed information, a key technology for the new generation of infrared focal plane detectors is to separate different wavelengths or different polarization states.
  • the infrared light is illuminated on different pixels to achieve multi-spectral multi-polarization imaging, and a color infrared image is formed through RGB rendering.
  • the existing infrared focal plane detectors that can achieve color are mainly refrigerated detectors based on mercury cadmium telluride materials, as shown in Figure 1.
  • the refrigerated detector based on mercury cadmium telluride material utilizes the vertical distribution of infrared absorption areas in different bands to achieve multispectral imaging.
  • the substrate of this kind of detector is relatively expensive, the wafer size is small and highly toxic, which is not conducive to mass production.
  • due to the stacked distribution of the absorption region it is difficult to control doping in the manufacturing process and ensure doping stability within the wafer and between wafer batches, and the etching process will cause large material damage. These process problems will lead to problems such as a decrease in detection quantum efficiency and a shift in detection wavelength.
  • detectors based on mercury cadmium telluride need to work at extremely low temperatures to ensure a small enough dark current, so they need to use refrigeration equipment such as Dewar bottles, which further increases the system cost.
  • detectors based on mercury cadmium telluride can often only distinguish between short-wave infrared (SWIR), mid-wave infrared (MWIR), and long-wave infrared (LWIR), which are wider bands, and are difficult to distinguish finer spectral segments. It cannot meet the demand for more detailed infrared images.
  • an infrared microbolometer detector including: a first substrate, a detector readout circuit and a microbolometer microelectromechanical system sequentially disposed on one side of the first substrate.
  • the system structure, the pixel-level metasurface layer is arranged on the side of the microbolometer micro-electromechanical system structure away from the first substrate.
  • the pixel-level metasurface layer includes a plurality of pixel-level metasurface minimum units, and the pixel-level metasurface minimum unit
  • the size M meets the following conditions:
  • ⁇ is the wavelength of incident light
  • n meta is the refractive index of the pixel-level metasurface layer.
  • the pixel-level metasurface layer provided by the embodiments of the present application includes multiple pixel-level metasurface minimum units. The size of each pixel-level metasurface minimum unit is smaller than the wavelength of the incident light. It can achieve fine distinction of the incident light, and the differentiated The incident light is concentrated into a specific microbolometer microelectromechanical system structure so that the detector readout circuit can read it and ultimately obtain a more detailed infrared image.
  • Figure 2 is a schematic cross-sectional structural diagram of an infrared microbolometer detector provided by an embodiment of the present application.
  • Figure 3 shows an infrared microbolometer detector provided by an embodiment of the present application. Side cutaway view of the heat meter detector.
  • the infrared microbolometer detector provided by the embodiment of the present application can achieve refined differentiation of spectral segments, especially for the long-wave infrared band, especially in the 8-14um wavelength range, and can achieve color infrared imaging or polarized infrared imaging.
  • the infrared microbolometer detector 100 provided by the embodiment of the present application includes: a first substrate, a detector readout circuit (Read Out Integrated Circuit, ROIC) 106 and a microbolometer disposed in sequence on one side of the first substrate.
  • Thermal meter MEMS structure 105 Thermal meter MEMS structure 105.
  • the first substrate is a wafer
  • the detector readout circuit 106 can be a complementary metal oxide semiconductor (Complementary Metal Oxide Semiconductor, CMOS) circuit, which has been integrated on the first substrate to form a detection detector. readout circuit wafer.
  • CMOS complementary Metal Oxide Semiconductor
  • a microbolometer MEMS structure 105 is provided on the side of the detector readout circuit 106 away from the first substrate, for receiving incident light and converting it into electrical signals for transmission to the detector readout circuit 106 .
  • the microbolometer microelectromechanical system structure 105 can also be called the microbolometer MEMS structure.
  • the infrared microbolometer detector 100 provided by the embodiment of the present application includes: a pixel-level metasurface layer 102 disposed on the side of the microbolometer MEMS structure 105 away from the first substrate.
  • the pixel-level metasurface layer 102 includes a plurality of pixel-level metasurface minimum units 304. Referring to FIG. 4, the size M of the pixel-level metasurface minimum unit 304 satisfies the following conditions:
  • ⁇ is the wavelength of incident light
  • n meta is the refractive index of the pixel-level metasurface layer.
  • the size M of the pixel-level metasurface minimum unit 304 is smaller than the wavelength of the incident light.
  • the size of each pixel-level metasurface minimum unit 304 is smaller than the wavelength of the incident light, it is possible to achieve Fine differentiation of light, and focusing the differentiated incident light into a specific microbolometer microelectromechanical system structure so that the detector readout circuit can read and ultimately obtain a more detailed infrared image.
  • the size M of the pixel-level metasurface minimum unit 304 may be much smaller than the wavelength of the incident light, for example, smaller than one-tenth of the wavelength of the incident light.
  • the pixel-level metasurface layer 102 provided by the embodiment of the present application is different from the current traditional metasurface layer.
  • the size M of the minimum unit 304 of the pixel-level metasurface provided by the embodiment of the present application can be smaller than the period U of the traditional metasurface layer.
  • NA is the numerical aperture.
  • the inequality related to the numerical aperture in the above formula refers to the fact that the traditional metasurface layer needs to meet the Nyquist sampling critical condition.
  • the inequality related to the refractive index of the pixel-level metasurface layer refers to the fact that the traditional metasurface layer needs to satisfy the requirement that no second-order diffraction occurs under oblique incident light conditions.
  • the size M of the minimum unit 304 of the pixel-level metasurface provided by the embodiment of the present application is not limited by this condition, the pixel-level metasurface layer 102 provided by the embodiment of the present application can allow high-order diffraction, so that when dealing with the pixel-level supersurface
  • the size M of the smallest unit 304 of the pixel-level metasurface can be adjusted without restrictions, and M can be much smaller than the size of the smallest unit of the traditional metasurface layer.
  • the detector readout circuit 106 and the microbolometer MEMS structure 105 include a plurality of detector unit pixels 303, N detector units
  • the pixels 303 constitute one detector equivalent pixel 302.
  • the pixel-level metasurface layer includes multiple pixel-level metasurface units 301.
  • the multiple pixel-level metasurface units 301 include multiple pixel-level metasurface minimum units 304, where N is A positive integer, the size of the pixel-level metasurface unit 301 and the detector equivalent pixel 303 are the same and correspond one-to-one, as shown in Figure 4 .
  • N detector unit pixels 303 are defined as one detector equivalent pixel 302.
  • the value of N can be determined according to actual needs.
  • the detector equivalent pixels 302 may include four detector unit pixels 303, as shown in Figure 5(a), nine detector unit pixels 303, as shown in Figure 5(b), or one detection unit pixel 303, as shown in Figure 5(b).
  • the detector unit pixels 303 are shown in FIG. 5(e).
  • the detector unit pixels 303 can be arranged to form a rectangle, a vertical line column or a horizontal line column, as shown in FIG. 5(a) to 5(e).
  • the pixel-level metasurface unit 301 is located directly above the detector equivalent pixel 302.
  • the side lengths of the pixel-level metasurface unit 301 in the X direction and the Y direction are equal to the side lengths of the detector equivalent pixel 302, and both
  • the structure is aligned along the optical axis Z direction, that is, perpendicular to the direction of the first substrate, as shown in reference 4.
  • the pixel-level metasurface unit 301 and the detector equivalent pixel 303 have the same size and one-to-one correspondence, so that the output light of the pixel-level metasurface unit 301 can, under ideal circumstances, only act on the light directly below the metasurface.
  • On the detector equivalent pixel 302. There is a corresponding relationship between the infrared characteristics between the pixel-level metasurface unit 301 and the detector equivalent pixel 302 below. For example, after the infrared light passes through the pixel-level metasurface layer 102, it focuses infrared of different wavelengths onto a specific lower detector unit pixel 303. On the top, each detector unit pixel 303 corresponds to a specific wave band.
  • incident infrared light of 8-14um passes through the pixel-level metasurface layer 102 and is divided into three beams of infrared light, respectively.
  • Infrared light of 8-10um, infrared light of 10-12um and infrared light of 12-14um are respectively incident on the detector unit pixel 303 of the corresponding waveband. In this way, fine distinction of incident light is finally achieved, enabling color infrared imaging.
  • the pixel-level metasurface layer 102 at least includes a metasurface substrate 201 and a metasurface pillar layer 202.
  • the metasurface pillar layer 202 is disposed on the side of the metasurface substrate 201 away from the first substrate.
  • the material of the metasurface substrate 201 can be silicon or germanium, and the material of the metasurface pillar layer 202 can also be silicon or germanium.
  • the material of the metasurface substrate 201 and the material of the metasurface pillar layer 202 is silicon, for infrared light, the reflectivity of the interface between silicon and air is high, and the metasurface pillar layer 202 can reduce Small infrared reflection, increased transmittance, and the effect of anti-reflection of infrared light on the basis of realizing the function of distinguishing spectral segments using the pixel-level metasurface layer 102.
  • the pixel-level metasurface layer 102 may include a coating layer 203.
  • the coating layer 203 is located at least on a side surface of the metasurface pillar layer 202 away from the metasurface substrate 201 for protecting the metasurface pillar layer 202 and Increase the transmittance of infrared light.
  • the material of the coating layer 203 may be zinc sulfide (ZnS) or magnesium fluoride (MgF 2 ), or other materials with high transmittance and high refractive index in the infrared.
  • the coating layer 203 may uniformly or non-uniformly cover the sidewalls of the metasurface pillar layer 202. As shown in FIG. 7, the coating layer 203 may not cover the sidewalls of the metasurface pillar layer 202.
  • the metasurface pillar layer 202 includes a plurality of convex structures
  • the pixel-level metasurface minimum unit (Minimum Meta-surface Cell) 304 may include a flat cell (Flat Cell) 305 and a convex unit 306, where , the protruding unit 306 has a protruding structure, as shown in FIG. 8 . That is to say, the interior of the pixel-level metasurface unit 301 can be divided into multiple pixel-level metasurface minimum units 304 with equal areas according to the specific design.
  • the pixel-level metasurface minimum unit 304 can have two flat units 305 and convex units 306
  • the convex unit 306 has a convex structure above the metasurface substrate 201, and the flat unit 305 does not have a convex structure above the metasurface substrate 201.
  • the shape of the protruding structure on the protruding unit 306 can be a completely filled rectangular column, an elliptical or a rounded rectangular column, or any other columnar structure.
  • the protruding structure in the embodiment of the present application is not limited to the shape shown in FIG. 8 , and can be modified in any way to meet the purpose of using the pixel-level metasurface layer 102 to distinguish spectral segments in the present application.
  • the height H of the protruding structure approximately satisfies the following conditions:
  • n i is the refractive index of the incident medium
  • ⁇ is the wavelength of the incident light
  • n meta is the refractive index of the pixel-level metasurface layer. That is to say, the height H of the metasurface pillar layer 202 mainly depends on the wavelength ⁇ of the incident infrared spectrum and the refractive index n meta of the pixel-level metasurface layer.
  • n i 1.
  • the height H of the protruding structure can be 6 to 8um.
  • the internal pattern of the pixel-level metasurface unit 301 may not be periodic, that is, the arrangement of the pixel-level metasurface minimum unit 304 may be non-periodic.
  • the entire pixel-level metasurface layer 102 can be composed of a pixel-level metasurface unit 301 to form a long-range periodic structure.
  • the entire pixel-level metasurface layer 102 is composed of a pattern (Pattern) A, that is, the pixel-level metasurface The unit 301 has periodicity, and the pixel-level metasurface minimum unit 304 does not have periodicity.
  • the entire pixel-level metasurface layer 102 may not be periodic at all. As shown in FIG.
  • the pixel-level metasurface unit 301 is composed of different patterns, and the pixels in each pixel-level metasurface unit 301
  • the size of the level metasurface minimum unit 304 may also be different, that is, the pixel level metasurface unit 301 does not have periodicity, and the pixel level metasurface minimum unit 304 does not have periodicity either.
  • the entire pixel-level metasurface layer 102 has no periodicity at all.
  • the pixel-level metasurface minimum units 304 at different positions of the entire pixel-level metasurface layer 102 can be designed with different sizes, so that local optimization can be achieved by changing the minimum size of the pixel-level metasurface minimum units 304 at specific positions.
  • the incident light angle of each pixel-level metasurface minimum unit 304 is different. In the pixel-level metasurface minimum unit 304 near the optical axis, the incident light is closer to vertical incidence, while in the pixel-level metasurface minimum unit 304 far away from the optical axis, the incident angle is larger.
  • multiple functions of the infrared microbolometer detector can be realized by changing the shape of the protruding structure or changing the size of the smallest unit of the pixel-level metasurface.
  • the multiple functions include at least dispersive refraction, narrow-band filtering, Light, polarized refraction and local focusing are introduced in detail below:
  • the first possible function is dispersive refraction.
  • the incident infrared light of different wavelengths is generated at specific refraction angles and focused on a specific detector unit pixel 303.
  • the lower three detector unit pixels 303 in Figure 10(a) respectively correspond to wavelengths of 8 ⁇ 10um, 10 ⁇ 12um and 12 ⁇ 14um.
  • the infrared light of different wavelengths is refracted to Corresponds to directly above the detector unit pixel 303.
  • the second possible function is narrow-band light filtering.
  • the pixel-level metasurface layer 102 has different reflectivities for incident infrared light of different wavelengths, and only allows narrow-band infrared light of a specific wavelength to pass through, and Dispersion and refraction are different. For infrared bands that are not allowed to be transmitted, the pixel-level metasurface layer 102 will reflect all these bands back. Taking the 8-10um detector unit pixel 303 as an example, infrared light in other wavelength bands, including those smaller than 8um and larger than 10um, will be reflected by the pixel-level metasurface layer 102, and only the infrared light with a wavelength of 8-10um passes through the pixel-level metasurface. The layer 102 is illuminated onto the detector unit pixel 303.
  • the third possible function is polarization refraction.
  • the incident infrared light of different polarization states is generated at a specific refraction angle and focused on a specific detector unit pixel 303.
  • the incident vertical linear polarization (vertical polarization), horizontal linear polarization (horizontal polarization) and circular polarization/elliptical polarization (circle polarization) infrared light produces different refraction angles after passing through the pixel-level metasurface layer 102.
  • the infrared light of different polarization states is refracted directly above the corresponding detector unit pixel 303.
  • the fourth possible function is local focusing.
  • the incident infrared light is generated and focused onto a specific detector unit pixel 303.
  • the wavelength and polarization state are no longer distinguished, but the incident light is converged. to the central region of the microbolometer MEMS structure 105 .
  • infrared light will illuminate the gaps between the detector unit pixels 303 or the bridge legs of the microbolometer microelectromechanical system structure. These infrared lights cannot be converted into The heat signal is therefore wasted.
  • the pixel-level metasurface layer 102 can focus infrared light to the central infrared absorption area 111 of the detector unit pixel 303, as shown in Figure 11, to increase the infrared absorption efficiency, and achieve pixel-level focusing to improve Infrared light utilization of infrared microbolometer detectors.
  • the pixel-level metasurface layer 102 when realizing the dispersive refraction function, the pixel-level metasurface layer 102 will refract infrared light of a specific wavelength on the entire surface to the specific detector unit pixel 303, so the efficiency and light energy utilization rate are higher.
  • the pixel-level metasurface layer 102 When realizing the narrow-band light filtering function, the pixel-level metasurface layer 102 usually has better wavelength selectivity and stronger out-of-band infrared light suppression.
  • the pixel-level metasurface layer 102 When realizing the polarization refraction function, the pixel-level metasurface layer 102 will refract the infrared light of a specific polarization state on the entire surface to the specific detector unit pixel 303. Therefore, compared with the traditional solution using polarizers, the efficiency and light energy utilization rate are higher.
  • the size of the detector unit pixel 303 is approximately 8-14um, which is close to the wavelength of long-wave infrared light. Therefore, if a traditional metasurface layer is used, the traditional metasurface layer corresponding to one detector unit pixel 303 Only a small number of protruding structures can be formed in the surface unit. However, in practical applications, the greater the number of protruding structures arranged in a unit pixel, the more precise phase control can be achieved. Therefore, the total area of a traditional metasurface layer is larger than several times. Hundred times the unit pixel area, so that enough convex structures can be arranged to achieve specific functions.
  • the size of the pixel-level metasurface minimum unit 304 in the pixel-level metasurface layer 102 provided by the embodiment of the present application is much smaller than the wavelength of the incident infrared light, which represents the pixel-level metasurface unit corresponding to the equivalent pixel 302 of a detector.
  • a large number of protruding structures can be arranged in 301 to achieve specific functions in a limited area. Compared with traditional metasurface layers, the total area is greatly reduced.
  • the infrared microbolometer detector may include a wafer-level packaging cover 103, as shown in FIG. 2 or FIG. 12 .
  • the wafer level packaging cover 103 is disposed on the side of the microbolometer MEMS structure 105 away from the first substrate, and is used to form a vacuum airtight environment and protect the microbolometer MEMS structure 105 .
  • the pixel-level metasurface layer 102 may be disposed on the surface of the wafer-level packaging cover 103, or may not be disposed on the surface of the wafer-level packaging cover 103.
  • the following is a detailed introduction:
  • the pixel-level metasurface layer 102 can be disposed on one side surface of the wafer-level packaging cover 103, which can be the inner surface or the outer surface, as shown in FIG. 2 . That is to say, the pixel-level metasurface layer 102 can be integrated into the wafer-level packaging cover 103. Such a structure can facilitate the pixel-level metasurface layer 102 and the first substrate when the wafer-level packaging cover 103 is bonded to the first substrate.
  • the microbolometer microelectromechanical system structure 105 is aligned.
  • the pixel-level metasurface layer 102 is usually set at the focal plane position of the incident infrared lens. Therefore, the position of the pixel-level metasurface layer 102 requires relatively precise control.
  • the metasurface layer 102 is disposed on the wafer level packaging cover 103 to ensure accurate positioning.
  • the pixel-level metasurface layer 102 may not be disposed on the surface of the wafer-level packaging cover 103 , but may be disposed on a side of the wafer-level packaging cover 103 away from the first substrate.
  • the pixel-level metasurface layer 102 can be disposed on the surface of an independent metasurface optical element 110.
  • the metasurface optical element 110 is disposed on the side of the wafer-level packaging cover 103 away from the first substrate.
  • the pixel-level metasurface layer 102 may be disposed on a side surface of the metasurface optical element 110 away from the first substrate, as shown in FIG. 12 .
  • the infrared microbolometer detector may include an infrared anti-reflection layer 104.
  • the infrared anti-reflection layer 104 is used to increase the transmittance of infrared light and improve the final imaging effect.
  • the infrared anti-reflection layer 104 can use an optical coating method for anti-reflection, or an additional pixel-level super-surface layer can be formed for anti-reflection.
  • the infrared anti-reflection layer 104 is disposed on the side of the pixel-level meta-surface layer 102 away from the first substrate, or can also be disposed on the side of the pixel-level meta-surface layer 102 close to the first substrate.
  • the infrared anti-reflection layer 104 is disposed on the side of the pixel-level metasurface layer 102 away from the first substrate, which may be both sides of the wafer-level packaging cover 103 , and the side close to the first substrate may be A pixel-level metasurface layer 102 is provided, and an infrared anti-reflection layer 104 can be provided on the side away from the first substrate.
  • the infrared anti-reflection layer 104 is disposed on the side of the pixel-level meta-surface layer 102 close to the first substrate. Specifically, the infrared anti-reflection layer 104 is disposed on the pixel-level meta-surface layer 102 and the microbolometer micrometer. Between the electromechanical system structures 105, refer to Figure 2.
  • the infrared anti-reflection layer 104 is disposed on the side of the pixel-level metasurface layer 102 close to the first substrate, specifically, it can be both sides of the wafer-level packaging cover 103, where the side away from the first substrate A pixel-level metasurface layer 102 may be provided, and an infrared anti-reflection layer 104 may be provided on the side close to the first substrate.
  • the infrared anti-reflection layer 104 may be disposed on a side surface of the metasurface optical element 110 close to the first substrate and/or be disposed on a side surface of the wafer-level packaging cover 103 , refer to FIG. 12 shown.
  • the first substrate has a bonding ring 403 and an auxiliary positioning mark 404.
  • the bonding ring 403 surrounds the microbolometer MEMS structure 105.
  • the bonding ring 403 The size is the same as that of the wafer-level packaging cover 103.
  • the auxiliary positioning marks 404 are located on both sides of the bonding ring 403. The height of the auxiliary positioning marks 404 is greater than the height of the bonding ring 403.
  • the auxiliary positioning marks 404 are used for packaging the cover at the wafer level.
  • auxiliary positioning marks 404 can be made on both sides of the bonding ring 403 surrounding the microbolometer MEMS structure 105.
  • the auxiliary positioning marks 404 can be a certain distance higher than the bonding ring 403, so that during the bonding process, the upper The wafer level packaging cover 103 can be embedded in the structure of the auxiliary positioning mark 404 to prevent or reduce bonding offset to the greatest extent.
  • the shape of the auxiliary positioning marks 404 may include a rectangle, a rounded rectangle, a circle, or other graphics, and the distance between each auxiliary positioning mark 404 and the bonding ring 403 is equal.
  • the spacing between the auxiliary positioning marks 404 determines the size of the bonding offset. If the spacing is too large, the maximum allowable bonding offset will be too high. If the spacing is too small, contact will easily fail during bonding. As an example, the distance between the auxiliary positioning mark 404 and the bonding ring 403 is 0.5-2um.
  • Embodiments of the present application provide an infrared microbolometer detector, including: a first substrate, a detector readout circuit and a microbolometer microelectromechanical system structure sequentially disposed on one side of the first substrate,
  • the pixel-level metasurface layer is provided on the side of the microbolometer MEMS structure away from the first substrate.
  • the pixel-level metasurface layer includes a plurality of pixel-level metasurface minimum units, and the size of the pixel-level metasurface minimum unit is M. The following conditions:
  • ⁇ is the wavelength of incident light
  • n meta is the refractive index of the pixel-level metasurface layer.
  • the pixel-level metasurface layer provided by the embodiments of the present application includes multiple pixel-level metasurface minimum units. The size of each pixel-level metasurface minimum unit is smaller than the wavelength of the incident light. It can achieve fine distinction of the incident light, and the differentiated The incident light is concentrated into a specific microbolometer microelectromechanical system structure so that the detector readout circuit can read it and ultimately obtain a more detailed infrared image.
  • embodiments of the present application also provide a design method for an infrared microbolometer detector.
  • a flow chart is shown of a design method for an infrared microbolometer detector provided by an embodiment of the present application. The method includes the following steps:
  • S102 Use a simulated annealing algorithm to modify the shape of at least one of the minimum units of the pixel-level metasurface, and simulate to obtain the function value of the modified first heuristic function of the pixel-level metasurface unit.
  • S105 Simulate the pixel metasurface layer to obtain the function value of the second heuristic function of the pixel metasurface layer.
  • the second heuristic function represents the imaging effect of the pixel metasurface layer.
  • S106 Use a simulated annealing algorithm to modify the shape of at least one of the minimum units of the pixel-level metasurface, and simulate to obtain the function value of the modified second heuristic function of the pixel-level metasurface unit.
  • the design method of the infrared microbolometer detector focuses on the design method of the pixel-level metasurface layer.
  • the pixel-level metasurface layer it can be divided into pixel-level metasurface unit design and pixel-level supersurface layer.
  • the overall design of the surface layer has two parts, which are introduced in detail below:
  • pixel-level metasurface units are first randomly generated and simulated to obtain the function value of the first heuristic function H1 of the pixel-level metasurface unit.
  • the first heuristic function H1 represents the imaging effect of the pixel-level metasurface unit, which includes multiple pixel-level metasurface minimum units.
  • FDTD finite difference time domain
  • FEM finite element method
  • Simulation software simulate to obtain the function value of the first heuristic function H1 of the modified pixel-level metasurface unit, that is, use the first heuristic function H1 to quantify the difference in imaging effects.
  • the pixel-level metasurface unit is determined as the optimal metasurface unit, that is, the simulated annealing algorithm is used to continuously iterate, and an extreme point of the first heuristic function H1 is finally found, which is the optimal result of the pixel-level metasurface unit.
  • the optimal metasurface units are arranged periodically to form a pixel-level metasurface layer, and simulations such as finite difference time domain (FDTD)/finite element method (FEM) are called for the pixel metasurface layer.
  • Software simulate to obtain the function value of the second heuristic function H2 of the pixel metasurface layer.
  • the second heuristic function H2 represents the imaging effect of the pixel metasurface layer.
  • Use the simulated annealing algorithm to randomly modify the shape of at least one pixel-level metasurface minimum unit. Specifically, it can be extended to the pixel-level metasurface minimum unit under all equivalent excitation conditions, and simulate to obtain the second heuristic function of the modified pixel-level metasurface unit.
  • the function value of H2 is to use the second heuristic function H2 to quantify the difference in imaging effects. Repeat the steps of using the simulated annealing algorithm to modify the shape of at least one pixel-level metasurface minimum unit until the pixel-level metasurface layer corresponding to the extreme point of the second heuristic function H2 is determined, and the extreme point of the second heuristic function H2 corresponds to The pixel-level metasurface layer is determined as the optimal metasurface layer. Even if the simulated annealing algorithm is used to continuously iterate, an extreme point of the second heuristic function H2 is finally found, which is the optimal result of the overall pixel-level metasurface.
  • the design method of the pixel-level metasurface layer can refer to Figure 15.
  • the simulated annealing algorithm is used to optimize the metasurface unit: generate initial random metasurface units, perform simulation initialization, and define the minimum unit parameters of the metasurface. , for example, the size is M and the type is K. Determine whether the final annealing temperature of the simulated annealing algorithm has been reached. If so, redefine the parameters M and K to achieve better convergence effects. If not, generate an approximate unit of the simulated annealing algorithm.
  • the simulated annealing algorithm is used to optimize the entire metasurface: simulation initialization, define the minimum unit parameters of the local metasurface, for example, size M, type K, determine whether the final annealing temperature of the simulated annealing algorithm has been reached, and if so, redefine the parameters M and K, in order to achieve better convergence effect, if not, generate the simulated annealing algorithm approximate local unit, use the generated approximate unit to replace all found structural equivalent metasurface units, import the unit structure model into the simulation software, and update the simulation conditions , such as boundary addition, incident angle of infrared light, etc., use FDTD/FEM algorithm to simulate, use the second heuristic function H2(x) to evaluate the simulation results, and define the imaging effect (performance) parameters as H2(new)-H2(old) , determine whether the performance parameter is greater than 0.
  • simulation initialization define the minimum unit parameters of the local metasurface, for example, size M, type K, determine whether the final annealing temperature of the simulated annealing algorithm
  • accept the new approximation unit If so, accept the new approximation unit. If not, if it meets the Metropolis criterion, accept the new approximation unit and determine whether the maximum value of H2(x) can be found by simulating the new approximation unit. Whether the algorithm converges. If not, reduce the current annealing temperature, change the performance parameters, and repeat the steps to determine whether the final annealing temperature of the simulated annealing algorithm has been reached. If so, save the complete metasurface result and obtain the final optimized surface.
  • the photoresist can be compensated to a certain extent through technologies such as Optical Proximity Correction (OPC), but the pattern structure made by the final process is only improved, and the design and actual structure cannot be completely consistent.
  • OPC Optical Proximity Correction
  • the embodiments of the present application can obtain the pixel-level heuristic function before simulating the first heuristic function of the pixel-level metasurface unit or before simulating the pixel metasurface layer to obtain the second heuristic function of the pixel metasurface layer.
  • the actual process parameters of the smallest unit of the metasurface are used to adjust the shape of the smallest unit of the pixel-level metasurface according to the actual process parameters.
  • the design method provided by the embodiment of the present application provides step 131, which can modify the current structural model according to process simulation.
  • This step 131 will modify the original ideal design model to be closer to the actual process.
  • the fabricated structure makes the simulation results more accurate.
  • the model modification parameters are mainly obtained based on process experience, as shown in Figure 17.
  • the rectangular column is mainly modified into a rounded rectangular column, and the inclination angle of the column side wall is adjusted from the ideal 90° to 89.3 ⁇ 89.6°. The specific value depends on the size of the rounded rectangular column. According to the local density of the surrounding photolithography patterns, adjust the height of the rounded rectangular column and add a scallop pattern to the side wall.
  • Figure 17(b) is a schematic diagram of the simulation adjustment.
  • the simulated annealing algorithm is also improved.
  • the size of the smallest unit of the pixel-level metasurface is further increased.
  • Zoom out and repeat iteration step 132 as shown in Figure 15.
  • the advantage of reducing the size of the minimum unit of the pixel-level metasurface is that it increases the design variables of the pixel-level metasurface, making it easier to meet design requirements and achieve convergence. That is to say, when the local heuristic function does not converge, the minimum unit size of the pixel-level metasurface will be reduced.
  • the dimensions are further reduced to increase the range of design variables, improve metasurface optical performance and facilitate algorithm convergence.
  • the design method can be used to obtain a minimum unit size of the pixel-level metasurface that is adaptive to the design requirements, which can maximize the size of the pixel-level metasurface while meeting the design requirements. Limit the process difficulty.
  • This design method of adaptive minimum unit size of pixel-level metasurface generates a pixel-level metasurface layer that is characterized by local optimization and non-periodicity of the entire non-pixel metasurface layer.
  • incident light when incident light is incident, there are certain differences in the conditions of the incident light. For example, the incident light angle of the smallest unit of each pixel-level metasurface is different. In the smallest unit of the pixel-level metasurface near the optical axis, the incident light is closer to vertical incidence, while in the smallest unit of the pixel-level metasurface far away from the optical axis, the incident angle is larger.
  • the pixel-level metasurface layer will have a worse dispersion effect on infrared light with a larger incident angle, these locations with poor dispersion effects can be additionally optimized by changing the minimum size of the smallest unit of the pixel-level metasurface to improve infrared microradiation. Imaging effects of thermal meter detectors.
  • simulation results including second-order and higher-order diffraction can be obtained using simulation software such as FEM or FDTD, and then the most suitable pixel-level metasurface layer can be found heuristically through the simulated annealing algorithm.
  • the structure enables the designed pixel-level metasurface layer to allow high-order diffraction, so the size of the smallest unit of the pixel-level metasurface can be much smaller than that of the smallest unit of the traditional metasurface layer.
  • the various functions of the infrared microbolometer detector can be realized by modifying the definition of the heuristic function to realize different structural designs of the pixel-level metasurface layer.
  • embodiments of the present application also provide a method for manufacturing an infrared microbolometer detector.
  • a flow chart is shown of a manufacturing method of an infrared microbolometer detector provided by an embodiment of the present application. The method includes the following steps:
  • S201 sequentially form a detector readout circuit and a microbolometer microelectromechanical system structure on the first substrate.
  • S202 Form a pixel-level metasurface layer on the side of the microbolometer micro-electromechanical system structure away from the first substrate.
  • the detector readout circuit 106 and the microbolometer microelectromechanical system structure 105 can be formed sequentially on the first substrate.
  • the first substrate is a wafer
  • the detector readout circuit 106 can be a CMOS circuit that has been integrated on the first substrate to form the detector readout circuit wafer 406. Refer to Figure 13 Show.
  • a microbolometer MEMS structure 105 is formed on the detector readout circuit 106 .
  • the microbolometer MEMS structure 105 is used to receive incident light and convert it into electrical signals for transmission to the detector readout circuit 106 .
  • the microbolometer microelectromechanical system structure 105 can also be called the microbolometer MEMS structure.
  • a pixel-level metasurface layer is then formed on the microbolometer MEMS structure 105 .
  • the pixel-level metasurface layer includes multiple pixel-level metasurface minimum units.
  • the size M of the pixel-level metasurface minimum unit satisfies the following conditions:
  • ⁇ is the wavelength of incident light
  • n meta is the refractive index of the pixel-level metasurface layer.
  • a wafer-level packaging cover 103 can be formed on the microbolometer MEMS structure 105 to form a vacuum airtight environment to protect the microbolometer MEMS structure 105 .
  • the pixel-level metasurface layer 102 may be disposed on the surface of the wafer-level packaging cover 103, or may not be disposed on the surface of the wafer-level packaging cover 103.
  • the following is a detailed introduction:
  • the pixel-level metasurface layer 102 can be disposed on one side surface of the wafer-level packaging cover 103, which can be the inner surface or the outer surface, as shown in FIG. 2 . That is to say, the pixel-level meta-surface layer 102 can be integrated into the wafer-level packaging cover 103 to form a pixel-level meta-surface packaging cover wafer (ROIC wafer) 405, as shown in Figure 13. Specifically, it can be a wafer-level packaging One side surface of the cover 103 is etched to form the pixel-level metasurface layer 102 .
  • ROIC wafer pixel-level meta-surface packaging cover wafer
  • the pixel-level metasurface layer 102 and the microbolometer microelectromechanical system structure 105 need to be aligned to achieve a pixel size far smaller than the pixel size.
  • alignment Specifically, an alignment machine or a bonding machine with an infrared alignment function can be used, and the alignment pattern 401 provided on the pixel-level metasurface packaging cover wafer 405 and the alignment provided on the detector readout circuit wafer 406 can be used.
  • Graphic 402 assists in alignment.
  • auxiliary positioning marks 404 can be made on both sides of the bonding ring 403 surrounding the microbolometer MEMS structure 105.
  • the auxiliary positioning marks 404 can be a certain distance higher than the bonding ring 403, so that during the bonding process, the upper The wafer level packaging cover 103 can be embedded in the structure of the auxiliary positioning mark 404 to prevent or reduce bonding offset to the greatest extent.
  • the bonding ring 403 and the auxiliary positioning mark 404 can be formed on the first substrate.
  • the bonding ring 403 and the auxiliary positioning mark 404 can be formed on the detector readout circuit wafer 406, as shown in Figure 13 , the bonding ring 403 surrounds the microbolometer MEMS structure 105, the size of the bonding ring 403 is the same as the size of the wafer level packaging cover 103, the auxiliary positioning marks 404 are located on both sides of the bonding ring 403, the auxiliary positioning marks 404 The height is greater than the height of the bonding ring 403. Subsequently, the wafer-level packaging cover 103 and the first substrate can be bonded using the bonding ring 403 and the auxiliary positioning mark 404 in a direction away from the first substrate with the pixel-level metasurface layer.
  • the substrate material can be silicon or germanium.
  • the pattern shape of the photoresist layer is the pattern shape of the pixel-level supersurface layer to be formed.
  • DRIE Deep silicon etching
  • the protective layer can be an oxide layer or silicon nitride (SiN).
  • the protective layer is used to protect the formed metasurface pillar layer.
  • the pattern of the photolithography mark is the pattern of the bond and metal structure.
  • an optical anti-reflection coating or a pixel-level metasurface anti-reflection layer can be formed in the cavity.
  • a getter can be deposited within the cavity.
  • the pixel-level metasurface layer 102 may not be disposed on the surface of the wafer-level packaging cover 103 , but may be disposed on a side of the wafer-level packaging cover 103 away from the first substrate.
  • the pixel-level metasurface layer 102 can be disposed on the surface of an independent metasurface optical element 110.
  • the metasurface optical element 110 is disposed on the side of the wafer-level packaging cover 103 away from the first substrate.
  • the pixel-level metasurface layer 102 may be disposed on a side surface of the metasurface optical element 110 away from the first substrate, as shown in FIG. 12 . That is to say, the metasurface optical element 110 can be formed first, and then one side surface of the metasurface optical element 110 can be etched to form the pixel-level metasurface layer 102 .
  • the infrared microbolometer detector can include an infrared anti-reflection layer, which is used to increase the transmittance of infrared light and improve the final imaging effect.
  • the infrared anti-reflection layer can use an optical coating method for anti-reflection, as shown in Figure 20, or an additional pixel-level super-surface layer can be formed for anti-reflection, as shown in Figure 19 or Figure 21.
  • an infrared anti-reflection layer can also be formed on the other side of the metasurface optical element 110.
  • the first possible implementation method is to use optical coating method for infrared anti-reflection layer.
  • the infrared anti-reflection layer is formed on the other side of the meta-surface optical element.
  • Optical coatings form an infrared antireflection layer. Referring to Figure 20, the process flow includes 7 steps:
  • the substrate material can be silicon or germanium.
  • the pattern shape of the photoresist layer is the pattern shape of the pixel-level supersurface layer to be formed.
  • DRIE Deep silicon etching
  • the protective layer can be an oxide layer or silicon nitride (SiN).
  • the protective layer is used to protect the formed metasurface pillar layer.
  • the second possible implementation method is that the infrared anti-reflection layer uses an additional pixel-level meta-surface layer for anti-reflection.
  • the infrared anti-reflection layer uses an additional pixel-level meta-surface layer for anti-reflection.
  • the infrared anti-reflection layer is formed on the other side of the meta-surface optical element.
  • One side surface is etched to form an infrared anti-reflection layer. Referring to Figure 21, the process flow includes 8 steps:
  • the substrate material can be silicon or germanium.
  • the pattern shape of the photoresist layer is the pattern shape of the pixel-level supersurface layer to be formed.
  • DRIE Deep silicon etching
  • the PECVD process can be used.
  • the protective layer can be an oxide layer or silicon nitride (SiN).
  • the protective layer is used to protect the formed metasurface pillar layer.
  • DRIE Deep silicon etching
  • the manufacturing process of forming the infrared anti-reflection layer can also be added, so that the pixel-level super-surface layer and the infrared anti-reflection layer can be formed in the same series of processes, reducing the overall process cost. step.
  • embodiments of the present application also provide an infrared microbolometer system.
  • FIG. 22 is a schematic structural diagram of an infrared microbolometer system provided by an embodiment of the present application.
  • the infrared microbolometer system provided by the embodiment of the present application includes an infrared lens 101, a shutter 107, and any one of the infrared microbolometer detectors provided by the above embodiments.
  • the infrared microbolometer system may also include a ceramic tube base 108 and a plastic shell 109.
  • the pixel-level metasurface layer 102 When the pixel-level metasurface layer 102 is integrated into the wafer-level packaging cover 103, after the pixel-level metasurface packaging cover wafer 405 and the detector readout circuit wafer 406 are bonded, they can be divided into separate infrared micro-controllers. bolometer detectors and then ultimately an infrared microbolometer system.
  • the wafer-level packaging cover and infrared anti-reflection layer are located at the focal plane of the infrared lens. After the incident infrared light is imaged on the focal plane through the infrared lens, the infrared light of the pixels in the local area passes through the pixel-level metasurface layer. Effects such as different wavelength deflection or polarization refraction are produced, which are illuminated on different detector unit pixels. Finally, the infrared light with different wavelength information or different polarization information is mapped through the microbolometer micro-electromechanical system structure and the detector readout circuit. Become an RGB color infrared image.

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Abstract

一种红外微测辐射热计探测器（100）及其设计方法、制造方法和***，包括：第一衬底、探测器读出电路（106）、微测辐射热计微机电***结构（105）和像素级超表面层（102），像素级超表面层（102）包括多个像素级超表面最小单元（304），像素级超表面最小单元（304）的尺寸M满定以下条件：M＜λ/2nmeta，A为入射光波长，nmeta为像素级超表面层（102）的折射率。每个像素级超表面最小单元（304）的尺寸小于入射光波长，能够实现对于入射光的精细区分，并且将区分后的入射光汇聚到特定的微测辐射热计微机电***结构（105）中，以便探测器读出电路（106）进行读取，最终得到更加精细的红外图像。

Description

红外微测辐射热计探测器及其设计方法、制造方法和*** 技术领域
本发明涉及红外探测领域，特别涉及一种红外微测辐射热计探测器及其设计方法、制造方法和一种红外微测辐射热计***。
背景技术
近年来，彩色红外热成像技术成为新的研究热点。传统的红外热成像技术指的是待测物体所辐射的红外光通过镜头聚焦并被红外焦平面探测器接收，最终呈现出灰度级的单色红外图像。然而灰度级的单色红外图像所呈现的是宽波段内入射光共同作用的结果，以其中一种红外焦平面探测器，例如微测辐射热计(bolometer)为例,呈现的灰度图像通常包含8～14微米(um)波段的长波红外光的所有信息。由于灰度级的单色红外图像所呈现的是宽波段内入射光共同作用的结果，包含的细节信息非常有限，因此新一代红外焦平面探测器的一个关键技术就是分离不同波长的红外光，并照射到不同的像元上，以实现多光谱成像或多偏振态成像，并通过RGB渲染形成彩色红外图像。
但是现有的能够实现彩色的红外焦平面探测器主要是基于碲镉汞材料的制冷型探测器，基于碲镉汞的探测器往往只能区分短波红外，中波红外，长波红外这些较宽的波段，难以区分更细的光谱段。不能满足对于红外图像更加精细的需求。
发明内容
有鉴于此，本申请的目的在于提供一种红外微测辐射热计探测器及其设计方法和制造方法，该红外微测辐射热计探测器能够区分更细的光谱段，探测得到的红外图像能够具有较高的精细度。
为实现上述目的，本申请有如下技术方案：
本申请实施例提供一种红外微测辐射热计探测器，包括：
第一衬底以及依次设置于所述第一衬底一侧的探测器读出电路和微测辐射热计微机电***结构；
像素级超表面层，设置于所述微测辐射热计微机电***结构远离所述第一衬底的一侧；
所述像素级超表面层包括多个像素级超表面最小单元，所述像素级超表面最小单元的尺寸M满足以下条件：
Figure PCTCN2022117137-appb-000001
所述λ为入射光波长，所述n meta为像素级超表面层的折射率。
本申请实施例提供一种红外微测辐射热计探测器的设计方法，包括：
随机生成像素级超表面单元并仿真获取所述像素级超表面单元的第一启发函数的函数值，所述第一启发函数代表所述像素级超表面单元的成像效果，所述像素级超表面单元包括多个像素级超表面最小单元；
利用模拟退火算法修改至少一个所述像素级超表面最小单元的形状，并仿真获取修改后的所述像素级超表面单元的第一启发函数的函数值；
重复利用模拟退火算法修改至少一个所述像素级超表面最小单元的形状的步骤，直到确定第一启发函数的极值点对应的像素级超表面单元为止，将所述第一启发函数的极值点对应的像素级超表面单元确定为最优超表面单元；
将所述最优超表面单元按照周期排布，形成像素级超表面层；
对所述像素超表面层仿真获取所述像素超表面层的第二启发函数的函数值，所述第二启发函数代表所述像素超表面层的成像效果；
利用模拟退火算法修改至少一个所述像素级超表面最小单元的形状，并仿真获取修改后的所述像素级超表面单元的第二启发函数的函数值；
重复利用模拟退火算法修改至少一个所述像素级超表面最小单元的形状的步骤，直到确定第二启发函数的极值点对应的像素级超表面层为止，将所述第二启发函数的极值点对应的像素级超表面层确定为最优超表面层。
本申请实施例提供一种红外微测辐射热计探测器的制造方法，包括：
在所述第一衬底上依次形成探测器读出电路和微测辐射热计微机电***结构；
在所述微测辐射热计微机电***结构远离所述第一衬底的一侧形成像素级超表面层，所述像素级超表面层包括多个像素级超表面最小单元，所述像素级超表面最小单元的尺寸M满足以下条件：
Figure PCTCN2022117137-appb-000002
所述λ为入射光波长，所述n meta为像素级超表面层的折射率。
本申请实施例提供一种红外微测辐射热计***，其特征在于，包括红外镜头、快门片和上述实施例任意一项所述的红外微测辐射热计探测器。
本申请实施例提供了一种红外微测辐射热计探测器，其特征在于，包括：第一衬底以及依次设置于第一衬底一侧的探测器读出电路和微测辐射热计微机电***结构，像素级超表面层，设置于微测辐射热计微机电***结构远离第一衬底的一侧，像素级超表面层包括多个像素级超表面最小单元，像素级超表面最小单元的尺寸M满足以下条件：
Figure PCTCN2022117137-appb-000003
其中，λ为入射光波长，n meta为像素级超表面层的折射率。本申请实施例提供的像素级超表面层包括多个像素级超表面最小单元，每个像素级超表面最小单元的尺寸小于入射光波长，能够实现对于入射光的精细区分，并且将区分后的入射光汇聚到特定的微测辐射热计微机电***结构中，以便探测器读出电路进行读取最终得到更加精细的红外图像。
附图说明
为了更清楚地说明本申请实施例或现有技术中的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图是本申请的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这 些附图获得其它的附图。
图1示出了一种基于碲镉汞材料的制冷型探测器示意图；
图2示出了本申请实施例提供的一种红外微测辐射热计探测器的剖面结构示意图；
图3示出了本申请实施例提供的一种红外微测辐射热计探测器的侧剖视图；
图4示出了本申请实施例提供的一种红外微测辐射热计探测器的局部结构示意图；
图5示出了本申请实施例提供的一种探测器等效像素示意图；
图6示出了本申请实施例提供的另一种红外微测辐射热计探测器的局部结构示意图；
图7示出了本申请实施例提供的一种像素级超表面层的局部结构示意图；
图8示出了本申请实施例提供的多种像素级超表面最小单元的局部结构示意图；
图9(a)示出了本申请实施例提供的一种像素级超表面层的图形示意图；
图9(b)示出了本申请实施例提供的另一种像素级超表面层的图形示意图；
图10(a)示出了本申请实施例提供的一种红外微测辐射热计探测器的功能示意图；
图10(b)示出了本申请实施例提供的另一种红外微测辐射热计探测器的功能示意图；
图10(c)示出了本申请实施例提供的又一种红外微测辐射热计探测器的功能示意图；
图10(d)示出了本申请实施例提供的又一种红外微测辐射热计探测器的功能示意图；
图11示出了图10所示的红外微测辐射热计探测器的局部结构示意图；
图12示出了本申请实施例提供的另一种红外微测辐射热计探测器的剖面结构示意图；
图13示出了本申请实施例提供的一种红外微测辐射热计探测器的键合示意图；
图14示出了本申请实施例提供的一种红外微测辐射热计探测器的设计方法的流程图；
图15示出了本申请实施例提供的另一种红外微测辐射热计探测器的设计方法的流程图；
图16(a)示出了本申请实施例提供的一种红外微测辐射热计探测器的制造工艺的效果图；
图16(b)示出了本申请实施例提供的另一种红外微测辐射热计探测器的制造工艺的效果图；
图16(c)示出了本申请实施例提供的又一种红外微测辐射热计探测器的制造工艺的效果图；
图17(a)示出了本申请实施例提供的一种红外微测辐射热计探测器的仿真示意图；
图17(b)示出了图17(a)的仿真效果图；
图18示出了本申请实施例提供的一种红外微测辐射热计探测器的制造方法的流程图；
图19示出了本申请实施例提供的一种像素级超表面层的制造方法的流程图；
图20示出了本申请实施例提供的另一种像素级超表面层的制造方法的流程图；
图21示出了本申请实施例提供的又一种像素级超表面层的制造方法的流程图；
图22示出了本申请实施例提供的一种红外微测辐射热计***的结构示意图。
具体实施方式
为使本申请的上述目的、特征和优点能够更加明显易懂，下面结合附图对本申请的具 体实施方式做详细的说明。
在下面的描述中阐述了很多具体细节以便于充分理解本申请，但是本申请还可以采用其它不同于在此描述的其它方式来实施，本领域技术人员可以在不违背本申请内涵的情况下做类似推广，因此本申请不受下面公开的具体实施例的限制。
其次，本申请结合示意图进行详细描述，在详述本申请实施例时，为便于说明，表示器件结构的剖面图会不依一般比例作局部放大，而且所述示意图只是示例，其在此不应限制本申请保护的范围。此外，在实际制作中应包含长度、宽度及深度的三维空间尺寸。
近年来，彩色红外热成像技术成为新的研究热点。传统的红外热成像技术指的是待测物体所辐射的红外光通过镜头聚焦并被红外焦平面探测器接收，最终呈现出灰度级的单色红外图像。然而灰度级的单色红外图像所呈现的是宽波段内入射光共同作用的结果，以其中一种红外焦平面探测器，例如微测辐射热计(bolometer)为例,呈现的灰度图像通常包含8～14微米(um)波段的长波红外光的所有信息。由于灰度级的单色红外图像所呈现的是宽波段内入射光共同作用的结果，包含的细节信息非常有限，因此新一代红外焦平面探测器的一个关键技术就是分离不同波长或不同偏振态的红外光，并照射到不同的像元上，以实现多光谱多偏振成像，并通过RGB渲染形成彩色红外图像。
但是现有的能够实现彩色的红外焦平面探测器主要是基于碲镉汞材料的制冷型探测器，参考图1所示。基于碲镉汞材料的制冷型探测器，利用不同波段红外的吸收区进行垂直分布实现多光谱成像。这种探测器的衬底较为昂贵，晶圆尺寸小并且有剧毒，不利于大规模生产。此外由于吸收区的叠层分布，制造工艺中掺杂难以控制并保证晶圆内、晶圆批次间的掺杂稳定性，并且刻蚀过程会产生较大材料损伤。这些工艺问题都会导致探测量子效率下降，探测波长的偏移等问题。并且基于碲镉汞的制冷型探测器需要工作在极低温度下，以保证足够小的暗电流，因此需要使用杜瓦瓶等制冷设备，这进一步增加了***成本。此外，基于碲镉汞的探测器往往只能区分短波红外(SWIR)，中波红外(MWIR)，长波红外(LWIR)这些较宽的波段，难以区分更细的光谱段。不能满足对于红外图像更加精细的需求。
基于此，本申请实施例提供了一种红外微测辐射热计探测器，包括：第一衬底以及依次设置于第一衬底一侧的探测器读出电路和微测辐射热计微机电***结构，像素级超表面层，设置于微测辐射热计微机电***结构远离第一衬底的一侧，像素级超表面层包括多个像素级超表面最小单元，像素级超表面最小单元的尺寸M满足以下条件：
Figure PCTCN2022117137-appb-000004
其中，λ为入射光波长，n meta为像素级超表面层的折射率。本申请实施例提供的像素级超表面层包括多个像素级超表面最小单元，每个像素级超表面最小单元的尺寸小于入射光波长，能够实现对于入射光的精细区分，并且将区分后的入射光汇聚到特定的微测辐射热计微机电***结构中，以便探测器读出电路进行读取最终得到更加精细的红外图像。
为了更好地理解本申请的技术方案和技术效果，以下将结合附图对具体的实施例进行详细的描述。
参考图2或图3所示，图2为本申请实施例提供的一种红外微测辐射热计探测器的剖面结构示意图，图3示出了本申请实施例提供的一种红外微测辐射热计探测器的侧剖视图。本申请实施例提供的红外微测辐射热计探测器能够实现对光谱段的精细化区分，尤其对于长波红外波段，特别是8～14um波长范围内，能够实现彩色红外成像或偏振红外成像。
本申请实施例提供的红外微测辐射热计探测器100包括：第一衬底以及依次设置于第一衬底一侧的探测器读出电路(Read Out Integrated Circuit,ROIC)106和微测辐射热计微机电***结构105。
作为一种可能的实现方式，第一衬底为晶圆，探测器读出电路106可以是互补金属氧化物半导体(Complementary Metal Oxide Semiconductor，CMOS)电路，已经集成在第一衬底上，形成探测器读出电路晶圆。
在探测器读出电路106远离第一衬底的一侧设置有微测辐射热计微机电***结构105，用于接收入射光并转换成电信号传输给探测器读出电路106。微测辐射热计微机电***结构105又可称为微测辐射热计MEMS结构。
本申请实施例提供的红外微测辐射热计探测器100包括：像素级超表面层102，设置于微测辐射热计微机电***结构105远离第一衬底的一侧。
像素级超表面层102包括多个像素级超表面最小单元304，参考图4所示，像素级超表面最小单元304的尺寸M满足以下条件：
Figure PCTCN2022117137-appb-000005
其中，λ为入射光波长，n meta为像素级超表面层的折射率。
由此可见，在本申请的实施例中，像素级超表面最小单元304的尺寸M小于入射光的波长，当每个像素级超表面最小单元的尺寸都小于入射光波长时，能够实现对于入射光的精细区分，并且将区分后的入射光汇聚到特定的微测辐射热计微机电***结构中，以便探测器读出电路进行读取最终得到更加精细的红外图像。
在实际应用中，像素级超表面最小单元304的尺寸M可以远小于入射光的波长，例如小于十分之一入射光的波长。
本申请实施例提供的像素级超表面层102和当前传统超表面层不同，本申请实施例提供的像素级超表面最小单元304的尺寸M可以小于传统超表面层的周期U traditional的限制条件。
传统超表面层的周期U traditional的限制条件如下所示：
Figure PCTCN2022117137-appb-000006
其中，NA为数值孔径，上式中与数值孔径相关的不等式指的是传统超表面层需要满足奈奎斯特采样临界条件。与像素级超表面层的折射率相关的不等式指的是传统超表面层需要满足在斜入射光的条件下不产生2级衍射。但是由于本申请实施例提供的像素级超表面最小单元304的尺寸M不受该条件的限制，因此本申请实施例提供的像素级超表面层102可以允许高阶衍射，这样在对像素级超表面层102进行设计时，就可以对像素级超表面最小单元304的尺寸M进行无限制条件的调控，M可以远小于传统超表面层的最小单元的尺 寸。
在本申请的实施例中，在垂直于第一衬底的方向上，探测器读出电路106和微测辐射热计微机电***结构105包括多个探测器单元像素303，N个探测器单元像素303组成1个探测器等效像素302，像素级超表面层包括多个像素级超表面单元301，多个像素级超表面单元301包括多个像素级超表面最小单元304，其中，N为正整数，像素级超表面单元301和探测器等效像素303的尺寸相同并且一一对应，参考图4所示。
也就是说，将N个探测器单元像素303定义为一个探测器等效像素302。N的取值可以根据实际需求决定。具体的，探测器等效像素302可以包括4个探测器单元像素303，参考图5(a)所示，9个探测器单元像素303，参考图5(b)所示，或者，1个探测器单元像素303，参考图5(e)所示，探测器单元像素303可以排列形成矩形、垂直线列或水平线列，参考图5(a)-图5(e)所示。
像素级超表面单元301位于探测器等效像素302的正上方，在X方向上和Y方向上的像素级超表面单元301的边长和探测器等效像素302的边长相等，且两者结构沿着光轴Z方向，即垂直于第一衬底的方向对齐，参考4所示。
这样像素级超表面单元301和探测器等效像素303的尺寸相同并且一一对应的结构，能够实现像素级超表面单元301的输出光，在理想情况下，只作用于直接位于超表面下方的探测器等效像素302上。像素级超表面单元301和下方的探测器等效像素302存在红外特征对应的关系，例如红外光在经过像素级超表面层102后，将不同波长的红外聚焦到特定的下方探测器单元像素303上，每个探测器单元像素303对应着一个特定波段，参考图6所示，8-14um的入射红外(incident infrared)光，经过像素级超表面层102后，区分为3束红外光，分别为8-10um的红外光、10-12um的红外光和12-14um的红外光，分别入射到相应波段的探测器单元像素303。这样就最终实现了对于入射光的精细区分，能够实现彩色红外成像。
在本申请的实施例中，像素级超表面层102至少包括超表面衬底201和超表面柱层202，超表面柱层202设置于超表面衬底201远离第一衬底的一侧，参考图4所示。具体的，超表面衬底201的材料可以采用硅或锗,超表面柱层202的材料也可以采用硅或锗。
在本申请的实施例中，若超表面衬底201的材料和超表面柱层202的材料为硅，对于红外光来说，硅和空气界面的反射率较高，超表面柱层202可以减小红外反射，增加透过率，在实现利用像素级超表面层102区分光谱段功能的基础上，实现对红外光进行增透的效果。
在本申请的实施例中，像素级超表面层102可以包括镀膜层203，镀膜层203至少位于超表面柱层202远离超表面衬底201的一侧表面，用于保护超表面柱层202以及增加红外光的透过率。具体的，镀膜层203的材料可以是硫化锌(ZnS)或氟化镁(MgF 2)等在红外具有较高透过率，且折射率较大的材料。镀膜层203可以均匀或非均匀的覆盖在超表面柱层202的侧壁，如图7所示，镀膜层203也可以不覆盖超表面柱层202侧壁。
在本申请的实施例中，超表面柱层202包括多个凸起结构，像素级超表面最小单元(Minimum Meta-surface Cell)304可以包括平坦单元(Flat Cell)305和凸起单元306，其 中，凸起单元306具有凸起结构，参考图8所示。也就是说，在像素级超表面单元301内部，可以根据具体设计划分为多个面积相等的像素级超表面最小单元304，像素级超表面最小单元304可以有平坦单元305和凸起单元306两种，凸起单元306在超表面衬底201上方有凸起结构，平坦单元305则是超表面衬底201上方不具有凸起结构。凸起单元306上的凸起结构的形状可以是完全填满的矩形柱，也可以是椭圆或圆角矩形柱或其他任意柱状结构。本申请实施例中的凸起结构不仅限于图8所示的形状，可以进行任意变型，以便满足本申请中利用像素级超表面层102区分光谱段的目的。
在本申请的实施例中，凸起结构的高度H近似满足以下条件：
Figure PCTCN2022117137-appb-000007
其中，n i为入射介质的折射率，λ为入射光波长，n meta为像素级超表面层的折射率。也就是说，超表面柱层202的高度H主要取决于入射红外光谱的波长λ以及像素级超表面层的折射率n meta。通常在空气环境中，n i＝1，具体的，凸起结构的高度H可以是6～8um。
在本申请的实施例中，像素级超表面单元301的内部图形可以不具有周期性，即像素级超表面最小单元304的排布可以具有非周期性。例如，整个像素级超表面层102可以由一种像素级超表面单元301组成长程周期性结构，参考图9(a)所示，全部由一种图案(Pattern)A构成，即像素级超表面单元301具有周期性，像素级超表面最小单元304不具有周期性。又如，整个像素级超表面层102也可以完全不具有周期性，参考图9(b)所示，像素级超表面单元301由不同图案构成，并且每个像素级超表面单元301中的像素级超表面最小单元304的尺寸也有可能不同，即像素级超表面单元301不具有周期性，像素级超表面最小单元304也不具有周期性。整个像素级超表面层102完全不具有周期性。
也就是说，可以对整个像素级超表面层102不同位置的像素级超表面最小单元304设计不同的尺寸，这样可以通过改变特定位置的像素级超表面最小单元304的最小尺寸，实现局部优化。具体的，当入射光入射时，入射光的条件存在一定的差异，例如每个像素级超表面最小单元304的入射光入射角度不同。在光轴附近的像素级超表面最小单元304，入射光更接近垂直入射，而远离光轴的像素级超表面最小单元304，入射角更大。由于像素级超表面层102对于入射角度较大的红外光色散效果会变差，因此可以对这些色散效果差的位置，通过改变像素级超表面最小单元304的最小尺寸额外进行优化，提高红外微测辐射热计探测器的成像效果。
在本申请的实施例中，可以通过改变凸起结构的形状或改变像素级超表面最小单元的尺寸实现红外微测辐射热计探测器的多种功能，多种功能至少包括色散折射、窄带滤光、偏振折射和局部聚焦，下面进行具体介绍：
第一种可能的功能为色散折射，参考图10(a)所示，将入射的不同波长的红外光产生特定的折射角度，并汇聚到特定的探测器单元像素303上面。图10(a)中下方三个探测器单元像素303分别对应8～10um、10～12um和12～14um波长，入射红外光在经过像素级超表面层102后，不同波长的红外光被折射到对应探测器单元像素303的正上方。
第二种可能的功能为窄带滤光，参考图10(b)所示，像素级超表面层102对不同波长的入射红外光存在不同反射率，仅允许特定波长的窄带红外光透过，和色散折射不同， 对于不允许透过的红外波段，像素级超表面层102会将这些波段全部反射回去。以8～10um探测器单元像素303为例，其余波段的红外光，包括小于8um和大于10um的，都会被像素级超表面层102反射，只有8～10um波长的红外光透过像素级超表面层102，照射到探测器单元像素303上。
第三种可能的功能为偏振折射，参考图10(c)所示，将入射的不同偏振态的红外光产生特定的折射角度，并汇聚到特定的探测器单元像素303上面。图10(c)中，入射的垂直线偏振(vertical polarization)、水平线偏振(horizontal polarization)和圆偏振/椭圆偏振(circle polarization)红外光，经过像素级超表面层102产生了不同的折射角度，不同偏振态的红外光被折射到了对应探测器单元像素303的正上方。
第四种可能的功能为局部聚焦，参考图10(d)所示，将入射的红外光产生聚焦到特定的探测器单元像素303上，不再区分波长和偏振状态，而是将入射光会聚到微测辐射热计微机电***结构105的中心区域。在传统的红外微测辐射热计探测器中，红外光会照射到探测器单元像素303之间的间隙，或是微测辐射热计微机电***结构桥腿处，这些红外光是无法转换成热量信号的，因此会被浪费掉。但是在本申请实施例中，像素级超表面层102可以将红外光会聚到探测器单元像素303的中心红外吸收区111，参考图11所示，以增加红外吸收效率，实现像素级聚焦可以提高红外微测辐射热计探测器的红外光利用率。
在实际应用中，在实现色散折射功能时，像素级超表面层102会将整个表面的特定波长的红外光都折射到特定探测器单元像素303上，因此效率和光能利用率更高。在实现窄带滤光功能时，像素级超表面层102则对波长的选择性通常更好，带外红外光抑制更强。在实现偏振折射功能时，像素级超表面层102会将整个表面的特定偏振态的红外光都折射到特定探测器单元像素303上,因此和传统使用偏振片的方案相比效率和光能利用率更高。
在本申请的实施例中，探测器单元像素303的尺寸大约在8-14um，和长波红外光的波长较为接近，因此若采用传统超表面层，则在一个探测器单元像素303对应的传统超表面单元内只能形成少量的凸起结构，但是在实际应用中，单位像素内排布的凸起结构数量越多，越能实现精细的相位调控，因此传统超表面层的总面积要大于几百倍的单位像素面积，这样才能排布足够多的凸起结构，实现特定功能。但是本申请实施例提供的像素级超表面层102中的像素级超表面最小单元304的尺寸远小于入射的红外光的波长，代表着在一个探测器等效像素302对应的像素级超表面单元301内可以排布大量的凸起结构，实现在有限的面积内的特定功能，相较于传统超表面层，大大减小了总面积。
在本申请的实施例中，红外微测辐射热计探测器可以包括晶圆级封装盖103，参考图2或图12所示。晶圆级封装盖103设置于微测辐射热计微机电***结构105远离第一衬底的一侧，用于形成真空气密环境，保护微测辐射热计微机电***结构105。
像素级超表面层102可以设置在晶圆级封装盖103的表面，也可以不设置在晶圆级封装盖103的表面，下面进行具体介绍：
作为一种可能的实现方式，像素级超表面层102，可以设置于晶圆级封装盖103的一侧表面，可以是内表面也可以是外表面，参考图2所示。也就是说，可以将像素级超表面层102集成至晶圆级封装盖103，这样的结构可以实现在晶圆级封装盖103和第一衬底键 合时，方便像素级超表面层102和微测辐射热计微机电***结构105对齐，此外，像素级超表面层102通常设置在入射的红外镜头的焦平面位置，因此像素级超表面层102的位置需要较为精确的控制，将像素级超表面层102设置在晶圆级封装盖103上，可以确保位置准确。
作为另一种可能的实现方式，像素级超表面层102可以不设置在晶圆级封装盖103的表面，可以设置于晶圆级封装盖103远离第一衬底的一侧。具体的，像素级超表面层102可以设置在一个独立的超表面光学元件110的表面，超表面光学元件110设置于晶圆级封装盖103远离第一衬底的一侧，像素级超表面层102可以设置于超表面光学元件110远离第一衬底的一侧表面，参考图12所示。
在实际应用中，红外微测辐射热计探测器可以包括红外增透层104，红外增透层104用于增加红外光的透过率，提高最终的成像效果。具体的，红外增透层104可以使用光学镀膜的方法进行增透，也可以额外形成像素级超表面层进行增透。
作为一种可能的实现方式，红外增透层104设置于像素级超表面层102远离第一衬底的一侧，也可以设置于像素级超表面层102靠近第一衬底的一侧。
作为一种示例，红外增透层104设置于像素级超表面层102远离第一衬底的一侧具体可以是晶圆级封装盖103的两侧表面，其中靠近第一衬底的一侧可以设置像素级超表面层102，远离第一衬底的一侧可以设置红外增透层104。
作为另一种示例，红外增透层104设置于像素级超表面层102靠近第一衬底的一侧具体可以是红外增透层104设置于像素级超表面层102和微测辐射热计微机电***结构105之间，参考图2所示。
作为又一种示例，红外增透层104设置于像素级超表面层102靠近第一衬底的一侧具体可以是晶圆级封装盖103的两侧表面，其中远离第一衬底的一侧可以设置像素级超表面层102，靠近第一衬底的一侧可以设置红外增透层104。作为另一种可能的实现方式，红外增透层104可以设置于超表面光学元件110靠近第一衬底的一侧表面和/或设置于晶圆级封装盖103的一侧表面，参考图12所示。
在本申请的实施例中，第一衬底具有键合环403和辅助定位标记404，参考图13所示，键合环403围绕微测辐射热计微机电***结构105，键合环403的尺寸和晶圆级封装盖103的尺寸相同，辅助定位标记404位于键合环403两侧，辅助定位标记404的高度大于键合环403的高度，辅助定位标记404用于在晶圆级封装盖103和第一衬底键合时，辅助晶圆级封装盖103和键合环403一一对应。也就是说，键合过程中，第一衬底和晶圆级封装盖103在接触之后，被施加较高的压力，可能产生水平方向的偏移。对于普通的键合来说，由于不涉及像素之间的对位，较大的偏移是可以容忍的。但由于像素级超表面层102需要和其下方的对应微测辐射热计微机电***结构105对准，较大的键合偏移会极大的影响成像质量。因此可以在包围微测辐射热计微机电***结构105的键合环403两侧做辅助定位标记404，辅助定位标记404可以较键合环403高出一定距离，这样在键合过程中，上方的晶圆级封装盖103能够嵌入辅助定位标记404的结构中，最大程度的防止或减小键合偏移。
具体的，辅助定位标记404的形状可以包括矩形、圆角矩形、圆形或者其他图形，每个辅助定位标记404和键合环403之间的间距相等。辅助定位标记404之间的间距决定了键合偏移的尺寸，如果间距太大，最大允许的键合偏移量就会过高，如果间距太小，则在键合时容易不能接触。作为一种示例，辅助定位标记404和键合环403之间的间距在0.5～2um。
本申请实施例提供了一种红外微测辐射热计探测器，包括：第一衬底以及依次设置于第一衬底一侧的探测器读出电路和微测辐射热计微机电***结构，像素级超表面层，设置于微测辐射热计微机电***结构远离第一衬底的一侧，像素级超表面层包括多个像素级超表面最小单元，像素级超表面最小单元的尺寸M满足以下条件：
Figure PCTCN2022117137-appb-000008
其中，λ为入射光波长，n meta为像素级超表面层的折射率。本申请实施例提供的像素级超表面层包括多个像素级超表面最小单元，每个像素级超表面最小单元的尺寸小于入射光波长，能够实现对于入射光的精细区分，并且将区分后的入射光汇聚到特定的微测辐射热计微机电***结构中，以便探测器读出电路进行读取最终得到更加精细的红外图像。
基于以上实施例提供的红外微测辐射热计探测器，本申请实施例还提供了一种红外微测辐射热计探测器的设计方法。参考图14所示，为本申请实施例提供的一种红外微测辐射热计探测器的设计方法的流程图，该方法包括以下步骤：
S101，随机生成像素级超表面单元并仿真获取所述像素级超表面单元的第一启发函数(Heuristic Function)的函数值。
S102，利用模拟退火算法修改至少一个所述像素级超表面最小单元的形状，并仿真获取修改后的所述像素级超表面单元的第一启发函数的函数值。
S103，重复利用模拟退火算法修改至少一个所述像素级超表面最小单元的形状的步骤，直到确定第一启发函数的极值点对应的像素级超表面单元为止，将所述第一启发函数的极值点对应的像素级超表面单元确定为最优超表面单元。
S104，将所述最优超表面单元按照周期排布，形成像素级超表面层。
S105，对所述像素超表面层仿真获取所述像素超表面层的第二启发函数的函数值，所述第二启发函数代表所述像素超表面层的成像效果。
S106，利用模拟退火算法修改至少一个所述像素级超表面最小单元的形状，并仿真获取修改后的所述像素级超表面单元的第二启发函数的函数值。
S107，重复利用模拟退火算法修改至少一个所述像素级超表面最小单元的形状的步骤，直到确定第二启发函数的极值点对应的像素级超表面层为止，将所述第二启发函数的极值点对应的像素级超表面层确定为最优超表面层。
在本申请的实施例中，红外微测辐射热计探测器的设计方法重点在于像素级超表面层的设计方法，针对像素级超表面层，可以分为像素级超表面单元设计和像素级超表面层的整体设计两大部分，下面进行具体介绍：
针对像素级超表面单元设计，首先随机生成像素级超表面单元并仿真获取像素级超表面单元的第一启发函数H1的函数值。其中，第一启发函数H1代表像素级超表面单元的成 像效果，像素级超表面单元包括多个像素级超表面最小单元。利用模拟退火算法随机修改至少一个像素级超表面最小单元的形状，例如修改像素级超表面最小单元304的平坦或凸起状态，并调用有限时域差分(FDTD)/有限元方法(FEM)等仿真软件，仿真获取修改后的像素级超表面单元的第一启发函数H1的函数值，即利用第一启发函数H1来量化成像效果的差异。重复利用模拟退火算法修改至少一个像素级超表面最小单元的形状的步骤，直到确定第一启发函数H1的极值点对应的像素级超表面单元为止，将第一启发函数H1的极值点对应的像素级超表面单元确定为最优超表面单元，即使用模拟退火算法不断迭代，最终找到一个第一启发函数H1的极值点，即为像素级超表面单元的最优结果。
针对像素级超表面层的整体设计，将最优超表面单元按照周期排布，形成像素级超表面层，对像素超表面层调用有限时域差分(FDTD)/有限元方法(FEM)等仿真软件，仿真获取像素超表面层的第二启发函数H2的函数值，第二启发函数H2代表像素超表面层的成像效果。利用模拟退火算法随机修改至少一个像素级超表面最小单元的形状，具体可以推广到所有等效激励条件的像素级超表面最小单元，并仿真获取修改后的像素级超表面单元的第二启发函数H2的函数值，即利用第二启发函数H2来量化成像效果的差异。重复利用模拟退火算法修改至少一个像素级超表面最小单元的形状的步骤，直到确定第二启发函数H2的极值点对应的像素级超表面层为止，将第二启发函数H2的极值点对应的像素级超表面层确定为最优超表面层，即使用模拟退火算法不断迭代，最终找到一个第二启发函数H2的极值点，即为整体像素级超表面的最优结果。
作为一种示例，像素级超表面层的设计方法可以参考附图15所示，首先是利用模拟退火算法优化超表面单元：生成初始随机超表面单元，并进行仿真初始化，定义超表面最小单元参数，例如尺寸为M，类型为K，判断是否达到模拟退火算法的最终退火温度，若是，则重新定义参数M和K，以便达到更好的收敛效果，若否，则生成模拟退火算法近似单元，使用工艺仿真算法，修改单元结构模型，将单元结构模型导入仿真软件，更新仿真条件，例如边界添加，红外光的入射角等，利用FDTD/FEM算法进行仿真，利用第一启发函数H1(x)评估仿真结果，定义成像效果(performance)参数为H1(new)-H1(old)，判断performance参数是否大于0，若是，则接受新的近似单元，若否，如果满足Metropolis准则，则接受新的近似单元，判断新的近似单元进行仿真是否能够找到H1(x)的最大值，算法是否收敛，若否，则降低当前退火温度，改变performance参数，重复执行判断是否达到模拟退火算法的最终退火温度的步骤，若是，则保存当前超表面单元，将超表面单元周期性复制，填满整个像素区域。
之后是利用模拟退火算法优化整个超表面：仿真初始化，定义局部超表面最小单元参数，例如尺寸为M，类型为K，判断是否达到模拟退火算法的最终退火温度，若是，则重新定义参数M和K，以便达到更好的收敛效果，若否，则生成模拟退火算法近似局部单元，利用生成的近似单元替换所有找出的结构等效超表面单元，将单元结构模型导入仿真软件，更新仿真条件，例如边界添加，红外光的入射角等，利用FDTD/FEM算法进行仿真，利用第二启发函数H2(x)评估仿真结果，定义成像效果(performance)参数为H2(new)-H2(old)，判断performance参数是否大于0，若是，则接受新的近似单元，若否，如果满足 Metropolis准则，则接受新的近似单元，判断新的近似单元进行仿真是否能够找到H2(x)的最大值，算法是否收敛，若否，则降低当前退火温度，改变performance参数，重复执行判断是否达到模拟退火算法的最终退火温度的步骤，若是，则保存完整的超表面结果，得到最终的优化表面。
在本申请的实施例中，由于像素级超表面最小单元的关键尺寸都非常小，在实际制造过程中，光刻和刻蚀工艺的不理想性会表现的很明显。如果光刻板按照设计尺寸严格执行，最终制造出来的像素级超表面的结构和设计会存在较大的误差。这些误差有些是光刻时光场分布不均匀导致，参考图16(a)所示，有些是刻蚀时负载效应导致的刻蚀深度不均导致，参考图16(b)所示，还有的侧壁倾斜和贝壳效应(scallop)是深反应离子刻蚀(DRIE)刻蚀工艺的气体循环产生的，参考图16(c)所示。其中，光刻板可以通过光学临近校正(OPC)等技术进行一定的补偿，但最终工艺做出的图形结构也只是有所改善，并不能做到设计和实际做出的结构完全一致，为了降低设计和制造得到的结构的偏差，本申请实施例能够在仿真获取像素级超表面单元的第一启发函数之前或在对像素超表面层仿真获取像素超表面层的第二启发函数之前，获取像素级超表面最小单元的实际工艺参数，根据实际工艺参数调整像素级超表面最小单元的形状。
具体的，参考图15所示的设计流程图，本申请实施例提供的设计方法提供步骤131，能够根据工艺仿真修改当前结构模型，该步骤131会将原本理想的设计模型修改成为更接近实际工艺制造出的结构，使得仿真结果更加准确。其中模型修改参数主要依据工艺经验获得，参考图17所示。图17(a)中，主要是将矩形柱修改成为圆角矩形柱，柱子侧壁倾角从理想的90°调整为89.3～89.6°，具体值取决于圆角矩形柱的尺寸。根据周围光刻图形的局部密度(local density)，调节圆角矩形柱的高度，并在侧壁加入scallop图形，图17(b)为仿真调整示意图。
在本申请的实施例中，在像素级超表面层的设计方法中，还对模拟退火算法进行了改进，当达到最终退火温度，如果仍然未收敛，则将像素级超表面最小单元的尺寸进一步缩小，重新进行迭代步骤132，参考图15所示。缩小像素级超表面最小单元尺寸的优点是增加了像素级超表面的设计变量，更容易达到设计需求实现收敛，也就是说，当局部启发函数不收敛时，会将像素级超表面最小单元的尺寸进一步缩小，以提高设计变量的范围，提升超表面光学性能并促进算法收敛。但是像素级超表面最小单元的尺寸越小，工艺制造的难度就越高，因此可以使用设计方法获得一个设计需求自适应的像素级超表面最小单元尺寸，能够在满足设计要求的情况下，最大限度放宽工艺难度。
这种自适应像素级超表面最小单元尺寸的设计方法，生成的像素级超表面层的特点就是，可以存在局部优化和整个非像素超表面层的非周期性。具体的，当入射光入射时，入射光的条件存在一定的差异，例如每个像素级超表面最小单元的入射光入射角度不同。在光轴附近的像素级超表面最小单元，入射光更接近垂直入射，而远离光轴的像素级超表面最小单元，入射角更大。由于像素级超表面层对于入射角度较大的红外光色散效果会变差，因此可以对这些色散效果差的位置，通过改变像素级超表面最小单元的最小尺寸额外进行优化，提高红外微测辐射热计探测器的成像效果。
本申请实施例提出的像素级超表面层，使用FEM或FDTD等仿真软件能够获得包含2阶及更高阶衍射的仿真结果，再通过模拟退火算法启发式寻找到最适合的像素级超表面层的结构，使得设计出的像素级超表面层能够允许高阶衍射，因此像素级超表面最小单元的尺寸可以远小于传统超表面层的最小单元的尺寸。
在实际应用中，实现红外微测辐射热计探测器的多种功能可以通过修改启发函数的定义，实现对于像素级超表面层的不同结构设计。
基于以上实施例提供的红外微测辐射热计探测器，本申请实施例还提供了一种红外微测辐射热计探测器的制造方法。参考图18所示，为本申请实施例提供的一种红外微测辐射热计探测器的制造方法的流程图，该方法包括以下步骤：
S201，在所述第一衬底上依次形成探测器读出电路和微测辐射热计微机电***结构。
S202，在所述微测辐射热计微机电***结构远离所述第一衬底的一侧形成像素级超表面层。
在本申请的实施例中，为形成红外微测辐射热计探测器可以在第一衬底上依次形成探测器读出电路106和微测辐射热计微机电***结构105。
作为一种可能的实现方式，第一衬底为晶圆，探测器读出电路106可以是CMOS电路，已经集成在第一衬底上，形成探测器读出电路晶圆406，参考图13所示。
在探测器读出电路106上形成微测辐射热计微机电***结构105，微测辐射热计微机电***结构105用于接收入射光并转换成电信号传输给探测器读出电路106。微测辐射热计微机电***结构105又可称为微测辐射热计MEMS结构。
而后在微测辐射热计微机电***结构105上形成像素级超表面层。
像素级超表面层包括多个像素级超表面最小单元，像素级超表面最小单元的尺寸M满足以下条件：
Figure PCTCN2022117137-appb-000009
其中，λ为入射光波长，n meta为像素级超表面层的折射率。
在本申请的实施例中，可以在微测辐射热计微机电***结构105上形成晶圆级封装盖103，以便形成真空气密环境，保护微测辐射热计微机电***结构105。
像素级超表面层102可以设置在晶圆级封装盖103的表面，也可以不设置在晶圆级封装盖103的表面，下面进行具体介绍：
作为一种可能的实现方式，像素级超表面层102，可以设置于晶圆级封装盖103的一侧表面，可以是内表面也可以是外表面，参考图2所示。也就是说，可以将像素级超表面层102集成至晶圆级封装盖103，形成像素级超表面封装盖晶圆(ROIC wafer)405，参考图13所示，具体可以是对晶圆级封装盖103的一侧表面进行刻蚀，以便形成像素级超表面层102。
将像素级超表面封装盖晶圆405和探测器读出电路晶圆406键合时，需要将像素级超表面层102和微测辐射热计微机电***结构105对齐，实现远小于像素尺寸的对准。具体可以使用带有红外对准功能的对准机或键合机，可以利用设置于像素级超表面封装盖晶圆 405的对准图形401和设置于探测器读出电路晶圆406的对准图形402辅助进行对准。
在键合过程中，像素级超表面封装盖晶圆405和探测器读出电路晶圆406接触之后，被施加较高的压力，可能产生水平方向的偏移，这样两张晶圆之间的偏移会进一步增大。对于普通的键合来说，由于不涉及像素之间的对位，较大的偏移是可以容忍的。但由于像素级超表面层102需要和其下方的对应微测辐射热计微机电***结构105对准，较大的键合偏移会极大的影响成像质量。因此可以在包围微测辐射热计微机电***结构105的键合环403两侧做辅助定位标记404，辅助定位标记404可以较键合环403高出一定距离，这样在键合过程中，上方的晶圆级封装盖103能够嵌入辅助定位标记404的结构中，最大程度的防止或减小键合偏移。
也就是说，可以在第一衬底上形成键合环403和辅助定位标记404，具体可以在探测器读出电路晶圆406上形成键合环403和辅助定位标记404，参考图13所示，键合环403围绕微测辐射热计微机电***结构105，键合环403的尺寸和晶圆级封装盖103的尺寸相同，辅助定位标记404位于键合环403两侧，辅助定位标记404的高度大于键合环403的高度，后续可以以像素级超表面层远离第一衬底的方向，利用键合环403和辅助定位标记404键合晶圆级封装盖103和第一衬底。
下面对形成像素级超表面封装盖晶圆的工艺流程进行具体介绍，参考图19所示，包括16个步骤：
1.清理衬底(clean substrate)，衬底材料可以是硅或锗。
2.光刻或纳米压印，形成光刻胶层(photolithography or Nano-imprint)，光刻胶层的图形形状为即将形成的像素级超表面层的图形形状。
3.深硅刻蚀(DRIE)，即利用光刻胶层，对衬底进行刻蚀，形成像素级超表面层的超表面柱层。
4.剥离光刻胶(strip photoresist)。
5.形成保护层(PECVD SiN as protective layer)，具体可以利用PECVD工艺，保护层具体可以是氧化层或氮化硅(SiN)，保护层用于保护形成的超表面柱层。
6.翻转晶圆和溅射形成键合金属层(Flip the wafer and sputter bonding metal)。
7.形成BSA光刻标记(BSA photolithography mark)，该光刻标记的图形为键和金属结构的图形。
8.对键合金属层进行刻蚀(etch metal)，使得键合金属层图形化。
9.剥离光刻胶(strip photoresist)。
10.形成光刻腔层(photolithography cavity layer)，以便后续形成空腔。
11.刻蚀形成空腔(DRIE cavity)
12.可选地，可以在空腔内形成光学增透涂层或像素级超表面增透层(coating or metasurface)，。
13.可选地，可以在空腔内沉积吸气剂(deposite getter)。
14.剥离光刻胶(strip photoresist)。
15.去除保护层(remove SiN)。
16.和像素级超表面封装盖晶圆键合(ROIC wafer bonding)。
作为另一种可能的实现方式，像素级超表面层102可以不设置在晶圆级封装盖103的表面，可以设置于晶圆级封装盖103远离第一衬底的一侧。具体的，像素级超表面层102可以设置在一个独立的超表面光学元件110的表面，超表面光学元件110设置于晶圆级封装盖103远离第一衬底的一侧，像素级超表面层102可以设置于超表面光学元件110远离第一衬底的一侧表面，参考图12所示。也就是说，可以首先形成超表面光学元件110，而后对超表面光学元件110的一侧表面进行刻蚀，形成像素级超表面层102。
在实际应用中，红外微测辐射热计探测器可以包括红外增透层，红外增透层用于增加红外光的透过率，提高最终的成像效果。具体的，红外增透层可以使用光学镀膜的方法进行增透，参考图20所示，也可以额外形成像素级超表面层进行增透，参考图19或图21所示。
在实际应用中，在超表面光学元件110的表面上形成像素级超表面层102时，还可以在超表面光学元件110的另一侧表面形成红外增透层，下面进行具体介绍：
第一种可能的实现方式，红外增透层使用光学镀膜的方法进行增透，在超表面光学元件的一侧表面上形成像素级超表面层时，在超表面光学元件的另一侧表面进行光学镀膜形成红外增透层。参考图20所示，工艺流程包括7个步骤：
1.清理衬底(clean substrate)，衬底材料可以是硅或锗。
2.光刻或纳米压印，形成光刻胶层(photolithography or Nano-imprint)，光刻胶层的图形形状为即将形成的像素级超表面层的图形形状。
3.深硅刻蚀(DRIE)，即利用光刻胶层，对衬底进行刻蚀，形成像素级超表面层的超表面柱层。
4.剥离光刻胶(strip photoresist)。
5.形成保护层(PECVD SiN as protective layer)，具体可以利用PECVD工艺，保护层具体可以是氧化层或氮化硅(SiN)，保护层用于保护形成的超表面柱层。
6.翻转晶圆和形成红外增透层(Flip the wafer and coating)。
7.去除保护层(remove SiN)。
第二种可能的实现方式，红外增透层使用额外形成的像素级超表面层进行增透，在超表面光学元件的一侧表面上形成像素级超表面层时，在超表面光学元件的另一侧表面进行刻蚀形成红外增透层。参考图21所示，工艺流程包括8个步骤：
1.清理衬底(clean substrate)，衬底材料可以是硅或锗。
2.光刻或纳米压印，形成光刻胶层(photolithography or Nano-imprint)，光刻胶层的图形形状为即将形成的像素级超表面层的图形形状。
3.深硅刻蚀(DRIE)，即利用光刻胶层，对衬底进行刻蚀，形成像素级超表面层的超表面柱层。
4.剥离光刻胶(strip photoresist)。
5.形成保护层(PECVD SiN as protective layer)，具体可以利用PECVD工艺，保护层具体可以是氧化层或氮化硅(SiN)，保护层用于保护形成的超表面柱层。
6.翻转晶圆和光刻或纳米压印(Flip the wafer and photolithography or Nano-imprint)，即在另一侧表面形成光刻胶层，光刻胶层的图形形状为即将形成的红外增透层的图形形状。
7.深硅刻蚀(DRIE)，即利用光刻胶层，对衬底进行刻蚀，形成红外增透层。
4.剥离光刻胶(strip photoresist)。
9.去除保护层(remove SiN)。
由此可见，在形成像素级超表面层的制造工艺时，还可以增加形成红外增透层的制造工艺，以便能够在同一系列工艺中形成像素级超表面层和红外增透层，降低整体工艺步骤。
基于以上实施例提供的红外微测辐射热计探测器，本申请实施例还提供了一种红外微测辐射热计***。参考图22所示，为本申请实施例提供的一种红外微测辐射热计***的结构示意图。本申请实施例提供的红外微测辐射热计***包括红外镜头101、快门片107和上述实施例提供的任意一项红外微测辐射热计探测器。
具体的，红外微测辐射热计***还可以包括陶瓷管座108和塑料外壳109。
当像素级超表面层102集成于晶圆级封装盖103时，在键合完毕像素级超表面封装盖晶圆405和探测器读出电路晶圆406之后，可以将其分割为单独的红外微测辐射热计探测器，而后最终形成红外微测辐射热计***。
在实际应用中，晶圆级封装盖和红外增透层位于红外镜头的焦平面位置，入射的红外光在经过红外镜头在焦平面成像后，局部区域像素的红外光经过像素级超表面层，产生了不同波长偏转或偏振折射等效果，照射到不同的探测器单元像素上，最终通过微测辐射热计微机电***结构和探测器读出电路将不同波长信息或不同偏振信息的红外光映射成为RGB彩色红外图像。
本说明书中的各个实施例均采用递进的方式描述，各个实施例之间相同相似的部分互相参见即可，每个实施例重点说明的都是与其他实施例的不同之处。
上述各个附图对应的流程或结构的描述各有侧重，某个流程或结构中没有详述的部分，可以参见其他流程或结构的相关描述。
以上所述仅是本申请的优选实施方式，虽然本申请已以较佳实施例披露如上，然而并非用以限定本申请。任何熟悉本领域的技术人员，在不脱离本申请技术方案范围情况下，都可利用上述揭示的方法和技术内容对本申请技术方案做出许多可能的变动和修饰，或修改为等同变化的等效实施例。因此，凡是未脱离本申请技术方案的内容，依据本申请的技术实质对以上实施例所做的任何的简单修改、等同变化及修饰，均仍属于本申请技术方案保护的范围内。
本申请在上述各方面提供的实现方式的基础上，还可以进行进一步组合以提供更多实现方式。

Claims (20)

  1. 一种红外微测辐射热计探测器，其特征在于，包括：
    第一衬底以及依次设置于所述第一衬底一侧的探测器读出电路和微测辐射热计微机电***结构；
    像素级超表面层，设置于所述微测辐射热计微机电***结构远离所述第一衬底的一侧；
    所述像素级超表面层包括多个像素级超表面最小单元，所述像素级超表面最小单元的尺寸M满足以下条件：
    Figure PCTCN2022117137-appb-100001
    所述λ为入射光波长，所述n meta为像素级超表面层的折射率。
  2. 根据权利要求1所述的红外微测辐射热计探测器，其特征在于，在垂直于所述第一衬底的方向上，所述探测器读出电路和微测辐射热计微机电***结构包括多个探测器单元像素，N个所述探测器单元像素组成1个探测器等效像素，所述像素级超表面层包括多个像素级超表面单元，所述多个像素级超表面单元包括多个所述像素级超表面最小单元，所述N为正整数；
    所述像素级超表面单元和所述探测器等效像素的尺寸相同并且一一对应。
  3. 根据权利要求1所述的红外微测辐射热计探测器，其特征在于，所述像素级超表面层至少包括超表面衬底和超表面柱层，所述超表面柱层设置于所述超表面衬底远离所述第一衬底的一侧。
  4. 根据权利要求3所述的红外微测辐射热计探测器，其特征在于，所述超表面柱层包括多个凸起结构，所述像素级超表面最小单元包括平坦单元和凸起单元，所述凸起单元具有所述凸起结构。
  5. 根据权利要求4所述的红外微测辐射热计探测器，其特征在于，所述凸起结构的高度H近似满足以下条件：
    Figure PCTCN2022117137-appb-100002
    所述n i为入射介质的折射率。
  6. 根据权利要求1-5任意一项所述的红外微测辐射热计探测器，其特征在于，所述像素级超表面最小单元的排布具有非周期性。
  7. 根据权利要求1-5任意一项所述的红外微测辐射热计探测器，其特征在于，所述红外微测辐射热计探测器包括晶圆级封装盖；
    所述晶圆级封装盖设置于所述微测辐射热计微机电***结构远离所述第一衬底的一侧；
    所述像素级超表面层，设置于所述晶圆级封装盖的一侧表面。
  8. 根据权利要求7所述的红外微测辐射热计探测器，其特征在于，所述红外微测辐射热计探测器包括红外增透层；
    所述红外增透层设置于所述像素级超表面层远离所述第一衬底的一侧，或，所述红外增透层设置于所述像素级超表面层靠近所述第一衬底的一侧。
  9. 根据权利要求1-5任意一项所述的红外微测辐射热计探测器，其特征在于，所述红 外微测辐射热计探测器包括晶圆级封装盖；
    所述晶圆级封装盖设置于所述微测辐射热计微机电***结构远离所述第一衬底的一侧；
    所述像素级超表面层，设置于所述晶圆级封装盖远离所述第一衬底的一侧。
  10. 根据权利要求9所述的红外微测辐射热计探测器，其特征在于，所述红外微测辐射热计探测器包括超表面光学元件和红外增透层；
    所述超表面光学元件设置于所述晶圆级封装盖远离所述第一衬底的一侧；
    所述像素级超表面层，设置于所述超表面光学元件远离所述第一衬底的一侧表面；
    所述红外增透层，设置于所述超表面光学元件靠近所述第一衬底的一侧表面和/或设置于所述晶圆级封装盖的一侧表面。
  11. 根据权利要求7-10任意一项所述的红外微测辐射热计探测器，其特征在于，所述第一衬底具有键合环和辅助定位标记，所述键合环围绕所述微测辐射热计微机电***结构，所述键合环的尺寸和所述晶圆级封装盖的尺寸相同，所述辅助定位标记位于所述键合环两侧，所述辅助定位标记的高度大于所述键合环的高度，所述辅助定位标记用于在所述晶圆级封装盖和所述第一衬底键合时，辅助所述晶圆级封装盖和所述键合环一一对应。
  12. 根据权利要求4-11任意一项所述的红外微测辐射热计探测器，其特征在于，通过改变所述凸起结构的形状或改变所述像素级超表面最小单元的尺寸实现所述红外微测辐射热计探测器的多种功能，所述多种功能至少包括色散折射、窄带滤光、偏振折射和局部聚焦。
  13. 一种红外微测辐射热计探测器的设计方法，其特征在于，包括：
    随机生成像素级超表面单元并仿真获取所述像素级超表面单元的第一启发函数的函数值，所述第一启发函数代表所述像素级超表面单元的成像效果，所述像素级超表面单元包括多个像素级超表面最小单元；
    利用模拟退火算法修改至少一个所述像素级超表面最小单元的形状，并仿真获取修改后的所述像素级超表面单元的第一启发函数的函数值；
    重复利用模拟退火算法修改至少一个所述像素级超表面最小单元的形状的步骤，直到确定第一启发函数的极值点对应的像素级超表面单元为止，将所述第一启发函数的极值点对应的像素级超表面单元确定为最优超表面单元；
    将所述最优超表面单元按照周期排布，形成像素级超表面层；
    对所述像素超表面层仿真获取所述像素超表面层的第二启发函数的函数值，所述第二启发函数代表所述像素超表面层的成像效果；
    利用模拟退火算法修改至少一个所述像素级超表面最小单元的形状，并仿真获取修改后的所述像素级超表面单元的第二启发函数的函数值；
    重复利用模拟退火算法修改至少一个所述像素级超表面最小单元的形状的步骤，直到确定第二启发函数的极值点对应的像素级超表面层为止，将所述第二启发函数的极值点对应的像素级超表面层确定为最优超表面层。
  14. 根据权利要求13所述的红外微测辐射热计探测器的设计方法，其特征在于，在仿真获取所述像素级超表面单元的第一启发函数的函数值之前或在对所述像素超表面层仿真 获取所述像素超表面层的第二启发函数的函数值之前，所述方法还包括：
    获取所述像素级超表面最小单元的实际工艺参数；
    根据所述实际工艺参数调整所述像素级超表面最小单元的形状。
  15. 根据权利要求13所述的红外微测辐射热计探测器的设计方法，其特征在于，所述方法还包括：
    若在最终退火温度未能获取得到所述第一启发函数或第二启发函数的极值点，则缩小像素级超表面最小单元的尺寸，重新进入利用模拟退火算法修改至少一个所述像素级超表面最小单元的形状的步骤。
  16. 一种红外微测辐射热计探测器的制造方法，其特征在于，包括：
    在所述第一衬底上依次形成探测器读出电路和微测辐射热计微机电***结构；
    在所述微测辐射热计微机电***结构远离所述第一衬底的一侧形成像素级超表面层，所述像素级超表面层包括多个像素级超表面最小单元，所述像素级超表面最小单元的尺寸M满足以下条件：
    Figure PCTCN2022117137-appb-100003
    所述λ为入射光波长，所述n meta为像素级超表面层的折射率。
  17. 根据权利要求16所述的红外微测辐射热计探测器的制造方法，其特征在于，所述方法还包括：
    形成晶圆级封装盖；
    所述在所述微测辐射热计微机电***结构远离所述第一衬底的一侧形成像素级超表面层包括：
    对所述晶圆级封装盖的一侧表面进行刻蚀，形成像素级超表面层。
  18. 根据权利要求17所述的红外微测辐射热计探测器的制造方法，其特征在于，所述方法还包括：
    在所述第一衬底上形成键合环和辅助定位标记，所述键合环围绕所述微测辐射热计微机电***结构，所述键合环的尺寸和所述晶圆级封装盖的尺寸相同，所述辅助定位标记位于所述键合环两侧，所述辅助定位标记的高度大于所述键合环的高度；
    以所述像素级超表面层远离所述第一衬底的方向，利用所述键合环和所述辅助定位标记键合所述晶圆级封装盖和所述第一衬底。
  19. 根据权利要求16所述的红外微测辐射热计探测器的制造方法，其特征在于，所述方法还包括：
    形成超表面光学元件；
    所述在所述微测辐射热计微机电***结构远离所述第一衬底的一侧形成像素级超表面层包括：
    对所述超表面光学元件的一侧表面进行刻蚀，形成像素级超表面层。
  20. 一种红外微测辐射热计***，其特征在于，包括红外镜头、快门片和权利要求1-12任意一项所述的红外微测辐射热计探测器。
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Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110118605A (zh) * 2019-05-30 2019-08-13 中国科学院长春光学精密机械与物理研究所 一种谐振型宽光谱非制冷红外探测器及其制备方法
CN110349946A (zh) * 2019-07-30 2019-10-18 北京北方高业科技有限公司 一种温度图像传感器及其制备方法
US20200025619A1 (en) * 2018-04-17 2020-01-23 The Curators Of The University Of Missouri Frequency-Selective Metasurface Integrated Uncooled Microbolometers
CN111693466A (zh) * 2020-06-18 2020-09-22 清华大学 一种基于超表面的高光谱滤波装置
CN114072646A (zh) * 2019-05-30 2022-02-18 迈瑞迪创新科技有限公司 用于热成像的基于超材料的对焦透镜
CN114167604A (zh) * 2021-12-21 2022-03-11 福州大学 基于微尺寸结构优化的多子镜阵列成像元件设计方法
CN114739519A (zh) * 2022-06-09 2022-07-12 杭州海康微影传感科技有限公司 探测器的封装盖板及其制备方法、探测器
CN114967161A (zh) * 2022-04-29 2022-08-30 同济大学 一种多层膜自由几何超表面元件及制备方法

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20200025619A1 (en) * 2018-04-17 2020-01-23 The Curators Of The University Of Missouri Frequency-Selective Metasurface Integrated Uncooled Microbolometers
CN110118605A (zh) * 2019-05-30 2019-08-13 中国科学院长春光学精密机械与物理研究所 一种谐振型宽光谱非制冷红外探测器及其制备方法
CN114072646A (zh) * 2019-05-30 2022-02-18 迈瑞迪创新科技有限公司 用于热成像的基于超材料的对焦透镜
CN110349946A (zh) * 2019-07-30 2019-10-18 北京北方高业科技有限公司 一种温度图像传感器及其制备方法
CN111693466A (zh) * 2020-06-18 2020-09-22 清华大学 一种基于超表面的高光谱滤波装置
CN114167604A (zh) * 2021-12-21 2022-03-11 福州大学 基于微尺寸结构优化的多子镜阵列成像元件设计方法
CN114967161A (zh) * 2022-04-29 2022-08-30 同济大学 一种多层膜自由几何超表面元件及制备方法
CN114739519A (zh) * 2022-06-09 2022-07-12 杭州海康微影传感科技有限公司 探测器的封装盖板及其制备方法、探测器

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