A self-aligned terahertz metasurface microfluidic sensor and its preparation method

Abstract

The present invention discloses a self-aligned terahertz metasurface microfluidic sensor and a preparation method thereof, belonging to the fields of liquid detection and terahertz biochemical sensing. The present invention uses MEMS technology to etch and process a secondary step on a silicon base, prepares a terahertz metasurface composed of a metal microarray on an ultra-thin quartz cover layer, and then bonds and packages the ultra-thin quartz cover layer and the silicon base to obtain a self-aligned terahertz metasurface microfluidic sensor. The present invention not only solves the problem of liquid leakage in actual measurement, but also places the terahertz metasurface structure into the step of the processed silicon substrate. While achieving self-alignment, a microfluidic channel is also formed. Through the reflective metal film deposited on the silicon substrate, while preventing the downward transmission of electromagnetic waves, the terahertz wave is reflected upward, so that the substance to be measured in the microfluidic channel is in a strong field energy region and interacts fully with the terahertz wave, realizing high device sensitivity and quality factor.

Description

Technical Field

[0001] The present invention relates to the fields of liquid detection and terahertz biochemical sensing, and particularly to a self-aligned terahertz metasurface microfluidic sensor with high quality factor and high sensitivity integrated with a metasurface absorber and a microfluidic channel. Background Art

[0002] Terahertz waves (with a frequency range of 0.1 THz - 10 THz and a wavelength range of 3 mm - 0.03 mm) are electromagnetic waves with frequencies between the microwave band and the infrared band. They have unique properties such as low photon energy, strong penetrability, and fingerprint spectra of biological macromolecules, and thus have great application potential in the field of biological sample detection.

[0003] Electromagnetic metamaterials are artificial materials with sub-wavelength periodic structures that do not exist in nature, and they have unique properties such as negative permittivity and negative permeability that natural materials do not possess.

[0004] In recent years, terahertz time-domain spectroscopy (THz-TDS) technology has been favored by many researchers. Due to the characteristics that the refractive index and terahertz wave absorption rate of cancer cells are generally higher than those of normal cells, and the unique fingerprint spectra of biological macromolecules in the terahertz frequency band, terahertz technology has unique advantages in the detection of cancer cells and biological samples. Therefore, terahertz sensors based on terahertz metasurfaces and terahertz time-domain spectroscopy technology have shown great promise in the field of biochemical detection. However, at present, when most terahertz biosensors detect biological samples, the biological samples are dried on the sensor surface for detection, which is quite different from the liquid environment in which most biological molecules are located, resulting in large errors in the detection results. To overcome this problem and solve the problem of strong absorption of terahertz waves by the water environment of the sample to be measured, a terahertz metasurface sensor integrated with a microfluidic channel has been proposed.

[0005] In the 10th issue, volume 6, page 962 of Laser & Photonics Reviews in 2016, a sensor structure integrating a microfluidic channel into a terahertz absorber was reported, which greatly enhanced the interaction between the sample substance and terahertz waves. The measured sensitivity was 0.22 THz / RIU and the quality factor was less than 10; in the 10th issue, volume 8, page 3789 of Biomedical Optics Express in 2019, a dual-band terahertz metasurface microfluidic sensor was reported, and the measured sensitivities of the two absorption peaks were 0.47 THz / RIU and 0.51 THz / RIU respectively, and the quality factors were also only about 10. As the two most important performance indicators of a sensor, the low sensitivity and quality factor greatly limit the application space of terahertz sensor devices. Summary of the Invention

[0006] In view of the problems in the above-mentioned existing technologies, the present application proposes a self-aligned terahertz metasurface microfluidic sensor that integrates a microfluidic channel and a sensor and has high sensitivity and high quality factor.

[0007] The technical solution provided by the present invention is as follows:

[0008] A self-aligned terahertz metasurface microfluidic sensor, characterized in that it includes an ultra-thin quartz cover layer and a silicon base. The silicon base is longitudinally etched with a first-level step and a second-level step. A metal thin film is deposited on the entire step surface as a reflective metal film. A terahertz metasurface composed of a metal microarray is provided on the ultra-thin quartz cover layer. The ultra-thin quartz cover layer is embedded on the first-level step that matches its size. The terahertz metasurface and the silicon substrate form a microfluidic channel at the second-level step. The silicon base is provided with two through holes connected to the microfluidic channel for injecting and discharging the liquid sample to be measured in the microfluidic channel.

[0009] The present invention further provides a preparation method for the self-aligned terahertz metasurface microfluidic sensor, and its steps include:

[0010] 1) Prepare a terahertz metasurface composed of a metal microarray on the ultra-thin quartz cover layer. The specific steps are as follows:

[0011] 1-1) Clean the ultra-thin quartz wafer, clean it with acetone and isopropanol, and then dry it.

[0012] 1-2) Coat hexamethyldisilazane to increase the adhesion and stability of the photoresist.

[0013] 1-3) Coat the photoresist and spin-coat it.

[0014] 1-4) After pre-baking, perform ultraviolet exposure and development to pattern the photoresist.

[0015] 1-5) Electron beam evaporation is used to deposit a Ti film and a gold film in sequence.

[0016] 1-6) Clean it with acetone to remove the excess photoresist on the surface, and a gold microstructure array is formed on the ultra-thin quartz cover layer.

[0017] 2) The silicon base is longitudinally etched with a first-level step and a second-level step, and a metal thin film is deposited on the entire step surface as a reflective metal film. The specific steps are as follows:

[0018] 2-1) Clean the silicon wafer, clean it with acetone and isopropanol in sequence, and then dry it.

[0019] 2-2) Coat the photoresist, spin-coat it, and pre-bake it.

[0020] 2-3) The exposure area is the etching area of the first-level step.

[0021] 2-4) removing the photoresist denatured by exposure with a developer, and then hardening and developing and inspecting;

[0022] 2-5) performing the first dry etching on the silicon wafer, wherein the etching area is a first-level step etching area and the depth is the thickness of the ultra-thin quartz cover layer;

[0023] 2-6) Prepare for the second dry etching;

[0024] 2-7) The exposure area is a secondary step etching area;

[0025] 2-8) removing the photoresist denatured by exposure with a developer, and then hardening and developing and inspecting;

[0026] 2-9) performing a second dry etching on the basis of the first step, and the etching area is the second step etching area;

[0027] 2-10) Cleaning with acetone to remove excess photoresist on one side of the step;

[0028] 2-11) Operate on the other side of the silicon wafer and prepare for the third dry etching to etch the through silicon vias;

[0029] 2-12) irradiating the through hole with ultraviolet light to deform the photoresist in the area;

[0030] 2-13) removing the photoresist denatured by exposure with a developer, and then hardening and developing and inspecting;

[0031] 2-14) Using the through silicon via etching process, a third etching is performed on the silicon wafer to drill holes;

[0032] 2-15) Cleaning with acetone to remove excess photoresist on the silicon wafer;

[0033] 2-16) Electron beam evaporation sequentially coats the entire step surface with a Ti film and a gold film to form an emitting metal film;

[0034] 2-17) drilling holes at corresponding positions of the prepared block PDMS, aligning and bonding with the silicon base, and externally connecting a hollow steel needle, and the silicon base processing is now completed;

[0035] 3) Bonding and packaging of ultra-thin quartz cover layer and silicon base

[0036] 3-1) Spin-coat the circumferential area of the ultra-thin quartz cover layer with liquid PDMS or UV shadowless adhesive;

[0037] 3-2) The ultra-thin quartz cover layer is placed on a step on the silicon base for calibration and alignment, and the PDMS or UV shadowless adhesive is cured, and the bonding and packaging are completed.

[0038] The thickness h1 of the ultra-thin quartz layer of the present invention is 20 μm to 100 μm, and the diameter R1 is 10 mm to 20 mm. The metal microarray uses common metals such as Au, Ag, Al, and Cu, and the thickness is h2 = 120 nm to 250 nm. The shape of the unit structure of the metal microarray is a line structure, and its dimensions are length L = 35 μm to 70 μm, width D = 9 μm to 20 μm, and the period P of the unit structure x = P y = 70 μm to 140 μm. The shape of the terahertz microstructure is a hollow square ring structure, and its dimensions are the outer perimeter A = 35 μm to 70 μm, the outer width B = 15 μm to 30 μm, the square ring line width w = 5 μm to 10 μm, and the period P of the unit structure x = P y = 70 μm to 140 μm. The first-level step is a circular cavity with a depth h4 = 20 μm to 100 μm and R2 = 12 to 22 mm. The thickness of this step is the same as the thickness of the ultra-thin quartz layer, and its diameter is slightly larger than the diameter of the ultra-thin quartz layer. The second-level step is a square cavity with a side length C = 3 mm to 12 mm and a depth h5 = 3 μm to 6 μm. The reflective layer is a common metal thin film such as Au, Ag, Al, and Cu with a thickness of 120 nm to 250 nm.

[0039] The present invention uses the MEMS process to etch and process the second-level step on the silicon base. By preparing a terahertz metasurface composed of a metal microarray on the ultra-thin quartz cover layer, the ultra-thin quartz cover layer and the silicon base are bonded and packaged to obtain a self-aligned terahertz metasurface microfluidic sensor. The present invention not only solves the problem of liquid leakage in actual measurement, but also places the terahertz metasurface structure into the step of the processed silicon substrate. While achieving self-alignment, a microfluidic channel is also formed. The reflective metal film deposited on the silicon substrate prevents the downward transmission of electromagnetic waves and reflects terahertz waves upward, enabling the substance to be measured in the microfluidic channel to interact fully with the terahertz waves, thereby achieving high device sensitivity. Description of the Drawings

[0040] Figure 1 is a schematic diagram of the self-aligned terahertz metasurface microfluidic sensor of the present invention, where (a) is the overall schematic diagram and (b) is the cross-sectional schematic diagram;

[0041] Figure 2 is a structural schematic diagram of the self-aligned terahertz metasurface microfluidic sensor of the present invention;

[0042] Figure 3 is a schematic diagram of the unit structure in the metal microarray in a specific embodiment of the present invention, where (a) is a line structure and (b) is a hollow ring structure;

[0043] Figure 4It is the process flow diagram of the self - aligned terahertz microfluidic sensor in the specific embodiment of the present invention;

[0044] Figure 5 It is the schematic diagram of the performance parameter simulation of the unit structure as a line structure in the metal microarray of the specific embodiment of the present invention; among which (a) is the simulated absorption spectrum of the sensor without load, and (b) is the simulated absorption spectrum of the sensor with samples of different refractive indices injected into the microfluidic channel;

[0045] Figure 6 It is the schematic diagram of the performance parameter simulation of the unit structure as a hollow square - ring structure in the metal microarray of the specific embodiment of the present invention; among which (a) is the simulated absorption spectrum of the sensor without load, and (b) is the simulated absorption spectrum of the sensor with samples of different refractive indices injected into the microfluidic channel;

[0046] Figure 7 It is the processing physical drawing in the specific embodiment of the present invention; among which (a) is the unit structure as a line structure in the metal microarray; (b) is the unit structure as a hollow square - ring structure in the metal microarray; (c) is the ultra - thin quartz cover layer and the silicon base;

[0047] Figure 8 It is the processing physical photo of the self - aligned terahertz microfluidic sensor in the specific embodiment of the present invention;

[0048] Figure 9 It is the comparison diagram of the measured value without load and the simulation of the sensor prepared in the specific embodiment of the present invention; among which (a) is the comparison diagram of the terahertz metasurface microfluidic sensor with a line structure, and (b) is the comparison diagram of the terahertz metasurface microfluidic sensor with a square - ring structure;

[0049] In the figure: 1 - silicon base; 2 - reflective metal film; 3 - through - hole; 4 - ultra - thin quartz cover layer; 5 - metal microarray; 6 - micro - cavity. Specific embodiments

[0050] The purpose of the present invention is to design a self - aligned terahertz metasurface microfluidic sensor with high sensitivity and high quality factor, and propose its processing technology, complete the processing verification, and realize the micro - detection of biochemical samples in a liquid environment, with accurate and reliable detection results. The present invention will be described in detail below with reference to the drawings and examples.

[0051] The following embodiments are for further detailed description of the present invention. The embodiments are only exemplary and do not intend to limit the devices prepared according to the present invention to the materials, conditions or process parameters described herein.

[0052] The self - aligned terahertz metasurface microfluidic sensor of the present invention is as Figure 1As shown in the figure, it mainly consists of two parts: the upper layer is an ultra-thin quartz cover layer with a terahertz metasurface, and the lower layer is a silicon base with a two-level step engraved on it. Figure 2 It shows the relative sizes and relative positions of different parts. The thickness of the ultra-thin quartz cover layer is embedded into the circular first-level step on the silicon substrate that matches its size, forming a microfluidic channel in the middle with the silicon base, that is, at the square second-level step. Two through holes on the silicon substrate are used to externally connect microfluidic pipes, so as to realize the function of injecting the liquid sample to be measured into the microfluidic channel.

[0053] In a specific embodiment of the present invention, the thickness h1 of the ultra-thin quartz cover layer is 30 μm, and the diameter R1 is 16 mm. The metal microarray uses gold with a conductivity σ = 4.56×107 S / m and a thickness of h2 = 200 nm. The wavelength of the terahertz wave is between 3 μm and 3 mm. The size of the terahertz metasurface is a sub-wavelength structure, generally one-half, one-fourth, one-eighth, one-sixteenth, etc. of the wavelength. The total thickness of the silicon base is h6 = 500 μm. The processing technology of the silicon substrate mainly includes four major steps: 1. Drill two through holes at the corresponding positions on the silicon wafer for subsequent external connection of microfluidic pipes; 2. Deeply etch a circular first-level step on the silicon wafer with a diameter R2 = 16 - 18 mm and a depth h4 = h1 = 30 μm; 2. Continue to etch a square second-level step with a side length C = 10 mm and a depth h5 = h3 = 3 μm on the basis of the circular first-level step; 4. Deposit a 200-μm-thick gold as a reflective metal film on the entire step surface.

[0054] As Figure 3 shown, the present invention proposes a total of two terahertz metasurface microfluidic sensors with a working frequency of about 2.5 THz. The metasurface unit of Structure 1 is a line structure, with a size of length L = 35 μm and width D = 9 μm, and the period P of the unit structure x = P y = 70 μm; the metasurface unit of Structure 2 is a hollow square ring structure, with a size of outer perimeter A = 35 mm, outer width B = 15 μm, square ring line width w = 5 μm, and the period P of the unit structure x = P y = 70 μm. The above microfluidic channel is located between the terahertz metasurface layer and the silicon base, with a depth h3 = 3 μm.

[0055] As Figure 4 shown, the processing process flow of the self-aligned terahertz metasurface microfluidic sensor of the present invention. That is, after the upper-layer quartz metasurface and the bottom-layer silicon step base are processed separately, then packaging is carried out. The specific steps include:

[0056] First, a terahertz metasurface composed of a metal microarray is provided on the ultra-thin quartz cover layer, specifically:

[0057] 1. Cleaning and drying: Clean the quartz wafer with acetone and isopropyl alcohol, and then dry it.

[0058] 2. Adhesion enhancement treatment: Coating with hexamethyldisilazane (HDMS) to increase the adhesion and stability of the photoresist.

[0059] 3. Coating and spin-coating the photoresist.

[0060] 4. Pre-baking, exposure, and development: After pre-baking, perform ultraviolet exposure and development to pattern the photoresist.

[0061] 5. Film deposition: Electron beam evaporation is used to deposit Ti film and Au film in sequence.

[0062] 6. Photoresist removal: Clean with acetone to remove the excess photoresist on the surface, and form an array of Au microstructures on the quartz substrate.

[0063] II. Etching the second-level step on the silicon base, specifically:

[0064] 1. Cleaning, drying, and adhesion enhancement treatment: Clean the silicon wafer with acetone and isopropyl alcohol in sequence, and then dry it.

[0065] 2. Coating, spin-coating, and pre-baking the photoresist.

[0066] 3. Exposure: The exposure area is the first-level step etching area (a circle with a diameter of 18 mm).

[0067] 4. Development, hard baking, and development inspection: Remove the exposed and denatured photoresist with developer, then perform hard baking and development inspection.

[0068] 5. Etching: Perform the first dry etching on the silicon wafer. The etching area is a circular area with a diameter of 18 mm, and the depth is the thickness of the quartz wafer, that is, the etching depth is about 30 μm.

[0069] 6. Coating, spin-coating, and pre-baking the photoresist: Prepare for the second dry etching.

[0070] 7. Exposure: The exposure area is the second-level step etching area (a square with a side length of 10 mm).

[0071] 8. Development, hard baking, and development inspection: Remove the exposed and denatured photoresist with developer, then perform hard baking and development inspection.

[0072] 9. Etching: Perform the second dry etching on the basis of the first-level step. The etching area is a square area with a side length of 10 mm, and the depth is the height of the microcavity, which is 3 mm.

[0073] 10. Photoresist removal: Clean with acetone to remove the excess photoresist on one side of the step.

[0074] 11. Glue coating, glue leveling, pre-baking: operate on the other side of the silicon wafer, prepare for the third dry etching, etching silicon through vias;

[0075] 12. Exposure: UV light is applied to the through-hole to deform the photoresist in that area;

[0076] 13. Development, hardening, and development inspection: The denatured photoresist after exposure is removed with a developer, and then hardened and developed;

[0077] 14. Etching: Use the through silicon via etching process to perform a third etching on the silicon wafer to make holes;

[0078] 15. Removal of photoresist: Use acetone to clean and remove excess photoresist on the silicon wafer;

[0079] 16. Coating: Electron beam evaporation is used to coat Ti film and gold film on the step surface in sequence;

[0080] 17. Bonding: Drill holes at the corresponding positions of the prepared block PDMS, align and bond with the silicon base, and connect a hollow steel needle externally. At this point, the silicon base processing is completed.

[0081] 3. Bonding and packaging of ultra-thin quartz cover layer and silicon base

[0082] 1. Calibration and alignment: Place the ultra-thin quartz cover layer on the step on the silicon base and calibrate and align it;

[0083] 2. Bonding and packaging:

[0084] Method 1: Spin-coat liquid PDMS on the circumference of the ultra-thin quartz sheet and wait for the PDMS to solidify to achieve bonding and packaging.

[0085] Method 2: Spin-coat UV shadowless adhesive on the circumference of the ultra-thin quartz wafer (curing with ultraviolet light while spinning to prevent seepage). After the UV shadowless adhesive is cured, the device is packaged.

[0086] Based on the above-mentioned set of processing techniques, the designed terahertz metasurface microfluidic sensor was simulated before the actual processing of the designed sensor. Figure 5 As shown, the designed line array structure (structure 1) has a perfect absorption peak with an absorption rate of 99.8% at f=2.519THz. According to the quality factor calculation formula Q=f0 / FWHM, the quality factor of the device is as high as 102.8; when the refractive index of the sample analyte in the microfluidic channel changes, the frequency shifts significantly. According to the calculation formula S=Δf / Δn, the sensitivity calculated is as high as 0.6448THz / RIU.

[0087] like Figure 6As shown, the designed hollow ring array structure (Structure 2) has a perfect absorption peak with an absorption rate of 98.1% at f = 2.45 THz. According to the above quality factor and sensitivity calculation formulas, the device quality factor of this structure is 73.9, and the sensitivity is as high as 0.6526 THz / RIU.

[0088] Based on the above-mentioned set of processing techniques, the designed sensor was actually processed and tested. Figure 7 、 Figure 8 The sensor processed according to the process flow proposed by the present invention is shown. The sensor was measured without load. As Figure 9 shown, the measured results of the two designed structure sensors are basically consistent with the simulations, and the measured indexes are basically the same as the simulation indexes, which fully verifies that the sensors provided by the present invention have high sensitivity and quality factors.

[0089] Although the embodiment solutions of the present invention have been shown, they are not limited to those shown in the description and embodiments. It can be fully applied to various fields suitable for the present invention. Those of ordinary skill in the art can understand that: without departing from the principles and purposes of the present invention, various changes and improvements can be made to the embodiments, and these all belong to the protection scope of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. A self-aligned terahertz metasurface microfluidic sensor, characterized in that, It includes an ultra-thin quartz cover layer and a silicon base. The silicon base is longitudinally etched with a first-level step and a second-level step. A metal thin film is deposited on the surface of the entire step as a reflective metal film. A terahertz metasurface composed of a metal microarray is provided on the ultra-thin quartz cover layer. The ultra-thin quartz cover layer is embedded on the first-level step that matches its size. The terahertz metasurface and the silicon substrate form a microfluidic channel at the second-level step. The silicon base is provided with two through holes connected to the microfluidic channel for injecting and discharging the liquid sample to be measured in the microfluidic channel.

2. The self-aligned terahertz metasurface microfluidic sensor according to claim 1, characterized in that The thickness h1 of the ultra-thin quartz cover layer is 20μm - 100μm, and the diameter R1 is 10mm - 20mm.

3. The self-aligned terahertz metasurface microfluidic sensor according to claim 1, characterized in that The metal microarray is made of Au, Ag, Al or Cu, and the thickness is h2 = 120nm - 250nm.

4. The self-aligned terahertz metasurface microfluidic sensor according to claim 1, wherein The unit structure of the metal microarray is in the shape of a line structure, with a length L=35 μm to 70 μm, a width D=9 μm to 20 μm, and a period P of the unit structure. x =P y =70μm~140μm.

5. The self-aligned terahertz metasurface microfluidic sensor according to claim 1, wherein The shape of the terahertz microstructure is a hollow square ring structure, and its dimensions are as follows: the outer perimeter length A = 35 μm to 70 μm, the outer perimeter width B = 15 μm to 30 μm, the square ring line width w = 5 μm to 10 μm, and the period P of the unit structure x = P y = 70 μm to 140 μm.

6. The self-aligned terahertz metasurface microfluidic sensor according to claim 1, wherein The first-level step is a cylindrical region with a depth h4 = 20μm - 100μm and R2 = 12 - 22mm.

7. The self-alignment terahertz metasurface microfluidic sensor according to claim 1, wherein The second-level step is a square cavity with a side length C = 3mm - 12mm and a depth h5 = 3μm - 6μm.

8. The self-aligned terahertz metasurface microfluidic sensor according to claim 1, wherein, The reflective metal film is made of Au, Ag, Al or Cu, and its thickness range is 120nm - 250nm.

9. The preparation method of the self-aligned terahertz metasurface microfluidic sensor according to claim 1, the steps include: 1) Prepare a terahertz metasurface composed of a metal microarray on the ultra-thin quartz cover layer. The specific steps are: 1-1) Clean the ultra-thin quartz wafer, clean it with acetone and isopropyl alcohol, and then dry it. 1-2) Coat hexamethyldisilazane to increase the adhesion and stability of the photoresist. 1-3) Coat the photoresist and spin it evenly. 1-4) After pre-baking, perform ultraviolet exposure and development to pattern the photoresist. 1-5) Electron beam evaporation is used to deposit a Ti film and a gold film in sequence. 1-6) Clean with acetone to remove the excess photoresist on the surface, and a metal microstructure array is formed on the ultra-thin quartz cover layer. 2) Longitudinally etch the first-level step and the second-level step on the silicon base, and deposit a metal thin film on the surface of the entire step as a reflective metal film. The specific steps are: 2-1) Clean the silicon wafer, clean it with acetone and isopropyl alcohol in sequence, and then dry it. 2-2) Coat the photoresist, spin it evenly, and pre-bake. 2-3) The exposure area is the first-level step etching area. 2-4) Remove the exposed and denatured photoresist with a developer, then harden the film and perform development inspection. 2-5) Perform the first dry etching on the silicon wafer. The etching area is the first-level step etching area, and the depth is the thickness of the ultra-thin quartz cover layer. 2-6) Prepare for the second dry etching. 2-7) The exposure area is the second-level step etching area. 2-8) Remove the exposed and denatured photoresist with a developer, then harden the film and perform development inspection. 2-9) Perform the second dry etching on the basis of the first-level step. The etching area is the second-level step etching area. 2-10) Clean with acetone to remove the excess photoresist on one side of the step. 2-11) Operate on the other side of the silicon wafer and prepare for the third dry etching to etch the silicon through hole. 2-12) Irradiate the through hole position with ultraviolet light to deform the photoresist in this area. 2-13) Remove the exposed and denatured photoresist with a developer, then harden the film and perform development inspection. 2-14) Using the through silicon via etching process, a third etching is performed on the silicon wafer to drill holes; 2-15) Cleaning with acetone to remove excess photoresist on the silicon wafer; 2-16) Electron beam evaporation sequentially coats the entire step surface with a Ti film and a metal film; 2-17) Drill holes at the corresponding positions of the prepared block PDMS, align and bond with the silicon base, and connect a hollow steel needle externally. At this point, the silicon base processing is completed; 3) Bonding and packaging of ultra-thin quartz cover layer and silicon base 3-1) Spin-coat the circumferential area of the ultra-thin quartz cover layer with liquid PDMS or UV shadowless adhesive; 3-2) The ultra-thin quartz cover layer is placed on a step on the silicon base for calibration and alignment, and the PDMS or UV shadowless adhesive is cured, and the bonding and packaging are completed.

10. The method according to claim 9, wherein In step 3-1), when the UV shadowless adhesive is spin-coated on the circumferential area of the ultra-thin quartz cover layer, it is cured by ultraviolet light while being spin-coated.

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