Image sensor and forming method therefor

Abstract

An image sensor and a forming method therefor. The method comprises: acquiring a substrate, having a first surface and a second surface which are opposite to each other, wherein the substrate is provided with a plurality of photoelectric sensing areas, and the first surface exposes the surfaces of the photoelectric sensing areas; forming a filter film on the photoelectric sensing areas, wherein the filter film allows for passing of an optical signal having a wavelength greater than a preset wavelength; and forming a first protective layer on the surface of the filter film. On one hand, an optical signal of a specific fluorescence band can be obtained by configuring the filter film, so that a fluorescence imaging experiment can be performed subsequently by means of such fluorescence band, thereby realizing lens-free imaging of a fluorescence signal, and simplifying the fluorescence microscopic detection process; on the other hand, the filter film is formed on the photoelectric sensing areas having a flat surface, so that the thicknesses of all positions of the filter film are uniform, thereby reducing the possibility of diffuse reflection and scattering of the fluorescence signal on the surface of the filter film caused by non-uniform thickness of the filter film, and ensuring the reliability of the fluorescence microscopic detection result.

Description

Image sensor and method of forming the same

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on December 11, 2023, with application number 202311693435.4 and invention name “Image sensor and method for forming the same”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present invention relates to the field of semiconductor manufacturing technology, and in particular to an image sensor and a method for forming the same. Background Art

[0003] Fluorescence imaging technology can clearly monitor biomolecules, cells, tissues, and living organisms in real time and across multiple dimensions. With its high sensitivity and high resolution, fluorescence imaging has been widely used in disease diagnosis, drug distribution and metabolism assessment, and vascular bioimaging. Conventional fluorescence microscopy systems are primarily based on fluorescence microscopes. These traditional fluorescence microscopy systems require rigorous optical path design, precision-machined optical components, and complex platform construction. Consequently, these systems have long development cycles, are expensive, and are bulky. Furthermore, these systems require regular maintenance and calibration.

[0004] In order to overcome the shortcomings of traditional optical microscopy, save the above-mentioned complex optical path design and optical path system construction, and realize miniaturized imaging, some people have adopted simplified lens-free imaging technology. Lens-free imaging technology is a high-throughput microscopy technology that directly places the object to be measured on or close to the sensor surface for imaging without the aid of any lens. Lens-free imaging does not magnify the microscopic sample through a lens, but relies on a high-density pixel array to capture the image of the sample, and then restores the image through digital image processing technology. Since each tiny sensor pixel has a similar or smaller scale than the biological sample, high sensitivity, high resolution, and parallel detection can be achieved.

[0005] However, there are still many problems in the lensless detection of fluorescence signals. Summary of the Invention

[0006] The technical problem solved by the present invention is to provide an image sensor and a method for forming the same, so as to realize lensless detection of fluorescence signals.

[0007] To solve the above technical problems, an embodiment of the present invention provides a method for forming an image sensor, including: obtaining a substrate having a first surface and a second surface relative to each other, the substrate having a plurality of photoelectric sensitive areas, the first surface exposing the surface of the photoelectric sensitive areas; forming a filter film on the photoelectric sensitive areas, the filter film allowing light signals greater than a preset wavelength to pass through; and forming a first protective layer on the surface of the filter film.

[0008] Optionally, the base is a wafer substrate, and the method for obtaining the base includes: developing a corresponding semiconductor process based on the wafer to form a plurality of the photoelectric sensitive areas.

[0009] Optionally, the substrate is an independent chip substrate, and the method for obtaining the substrate includes: providing an initial image sensor, including: a substrate having a first surface and a second surface relative to each other, the substrate having a plurality of photoelectric sensitive areas, the first surface exposing the surface of the photoelectric sensitive area and the microlens structure located on the photoelectric sensitive area; removing the microlens structure.

[0010] Optionally, the method further includes: forming a device layer on the first surface or the second surface of the substrate; and forming a filter film on the surface of the device layer.

[0011] Optionally, it further includes: a device layer located on the surface of the first surface or the second surface of the substrate; and forming a filter film on the surface of the device layer.

[0012] Optionally, the substrate further has an interconnection area, which surrounds the plurality of photoelectric sensitive areas, and a surface of the interconnection area has a plurality of interconnection lines.

[0013] Optionally, the initial image sensor further has a first packaging structure, the first packaging structure covers the interconnection line and the microlens structure, and the first packaging structure includes a glass cover.

[0014] Optionally, before removing the microlens structure, the method further includes: removing the glass cover plate; the method of removing the glass cover plate includes: mechanical removal or thermal processing removal.

[0015] Optionally, after removing the glass cover plate and before removing the microlens structure, the method further includes: forming a second protective layer on the surface of the interconnection line.

[0016] Optionally, after removing the glass cover plate and before forming the second protective layer, the method further includes: removing impurities remaining on the glass cover plate.

[0017] Optionally, the method of removing the microlens structure includes: one or more combinations of mechanical grinding, chemical etching, or chemical mechanical polishing.

[0018] Optionally, after removing the microlens structure and before forming the filter film, the method further includes: cleaning the surface of the photoelectric sensitive area.

[0019] Optionally, the method for forming the filter film includes: acquiring parameters of the filter film; and forming the filter film using the parameters of the filter film.

[0020] Optionally, the method for obtaining the parameters of the filter film includes: obtaining the required light band, the optical parameters of the light band include the peak wavelength of the excitation light source and the wavelength bandwidth of the excitation light source; obtaining the filter film material; obtaining the parameters of the filter film based on the filter film material and the optical parameters, the parameters of the filter film include the number of layers of the filter film and the thickness of the filter film.

[0021] Optionally, the method for forming the filter film includes: spin coating of a light-absorbing dye, target magnetron sputtering or vapor deposition.

[0022] Optionally, after forming the filter film and before forming the first protective layer, the method further includes: forming a fiber optic plate microstructure on the surface of the filter film.

[0023] Optionally, the method for forming the optical fiber plate microstructure includes: forming an initial optical fiber plate microstructure on the surface of the filter film; and performing micro-nano processing on the initial optical fiber plate microstructure to form the optical fiber plate microstructure.

[0024] Optionally, after forming the first protective layer, the method further includes: forming a second packaging structure on a surface of the first protective layer, wherein the second packaging structure has a groove for carrying a sample to be tested.

[0025] Correspondingly, the technical solution of the present invention also provides an image sensor, including: a substrate having a first surface and a second surface relative to each other, the substrate having a plurality of photoelectric sensitive areas, the first surface exposing the surface of the photoelectric sensitive areas; a filter film located on the photoelectric sensitive areas, the filter film allowing light signals greater than a preset wavelength to pass through; and a first protective layer located on the surface of the filter film.

[0026] Optionally, it further includes: a device layer located on the surface of the first side of the substrate, or a device layer located on the surface of the second side of the substrate; the filter film is located on the surface of the device layer.

[0027] Optionally, it further includes: a fiber optic plate microstructure located between the filter film and the protective layer; the material of the fiber optic plate microstructure includes: silicon dioxide or titanium dioxide; the thickness range of the fiber optic plate microstructure is: 50nm to 100nm.

[0028] Optionally, the substrate further has an interconnection area, which surrounds the plurality of photoelectric sensitive areas, and a surface of the interconnection area has a plurality of interconnection lines.

[0029] Optionally, the method further includes: a second protective layer located on the surface of the interconnection line; the thickness of the second protective layer is in the range of 50 nm to 300 nm; and the material of the second protective layer includes silicon.

[0030] Optionally, the method further includes: a second packaging structure located on the surface of the first protective layer, wherein the second packaging structure has a groove for carrying a sample to be tested.

[0031] Optionally, it also includes: the material of the filter film includes: metal oxide or non-metal oxide; the metal oxide includes: titanium oxide, zirconium oxide or aluminum oxide; the non-metal oxide includes silicon oxide; the thickness range of the filter film is: 5μm to 20μm.

[0032] Optionally, the method further includes: a material of the first protective layer includes silicon dioxide, titanium dioxide or zirconium dioxide; and a thickness of the first protective layer ranges from 5 nm to 20 nm.

[0033] Optionally, the preset wavelength range of the light signal allowed to pass through the filter membrane is: 488nm~700nm, and the preset wavelength band of the light signal allowed to pass through the filter membrane includes: light wavelength greater than 488nm, light wavelength greater than 520nm or light wavelength greater than 660nm.

[0034] Compared with the prior art, the technical solution of the embodiment of the present invention has the following beneficial effects:

[0035] In the image sensor of the technical solution of the present invention, on the one hand, by setting a filter film, light signals of a specific fluorescence band can be obtained, which facilitates subsequent fluorescence imaging experiments using this fluorescence band; on the other hand, the filter film is located on a photoelectric sensitive area with a flat surface, so that the thickness of the filter film is uniform everywhere, reducing the possibility of diffuse reflection and scattering of the fluorescence signal on the surface of the filter film due to uneven thickness of the filter film. While realizing lensless imaging of the fluorescence signal, reducing the cost of fluorescence microscopy detection, and facilitating the fluorescence microscopy detection process, the reliability of the fluorescence microscopy detection results is guaranteed.

[0036] Furthermore, the device further includes a fiber optic plate microstructure located between the filter film and the protective layer. The fiber optic plate microstructure allows the fluorescence signal to be incident perpendicularly to the surface of the photoelectric sensing area, thereby reducing the possibility of fluorescence signal scattering, ensuring uniform light intensity collected by the photoelectric sensing area, and ensuring the reliability of fluorescence microscopy detection.

[0037] In the method for forming an image sensor according to the technical solution of the present invention, on the one hand, the provision of a filter film can capture light signals in a specific fluorescence band, facilitating subsequent fluorescence imaging experiments using this fluorescence band. This achieves lensless imaging of the fluorescence signal, reduces the cost of fluorescence microscopy, and simplifies the fluorescence microscopy process. Furthermore, the filter film is formed on a flat photoelectric sensitive area, resulting in a uniform thickness across the filter film. This reduces the possibility of diffuse reflection and scattering of the fluorescence signal on the filter film surface due to uneven filter film thickness, and reduces the possibility of large variations in light intensity collected by the photoelectric sensitive area due to diffuse reflection and scattering, thereby ensuring the reliability of the fluorescence microscopy results.

[0038] Furthermore, when the substrate is a wafer, the method for obtaining the substrate includes: performing corresponding semiconductor processing on the basis of the wafer to form a plurality of the photoelectric sensitive areas; when the substrate is an independent chip substrate, the method for obtaining the substrate includes: purchasing existing products and removing the microlens structure of the existing products, on the one hand, reducing production costs; on the other hand, forming a filter film on the surface of the photoelectric sensitive area, thereby enhancing the bonding force between the filter film and the surface of the photoelectric sensitive area.

[0039] Furthermore, after forming the filter film and before forming the first protective layer, the method further includes forming a fiber optic plate microstructure on the surface of the filter film. The fiber optic plate microstructure allows the fluorescence signal to be incident perpendicularly to the surface of the photoelectric sensing area, reducing the possibility of fluorescence signal scattering, ensuring uniform light intensity collected by the photoelectric sensing area, and ensuring the reliability of fluorescence microscopy detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0041] FIG1 is a schematic flow chart of a method for acquiring an image sensor in an embodiment of the present invention;

[0042] FIG2 is a schematic flow chart of a method for obtaining a substrate in one embodiment of the present invention;

[0043] FIG3 is a schematic flow chart of a method for obtaining a substrate in another embodiment of the present invention;

[0044] 4 to 12 are schematic structural diagrams of a process for forming an image sensor according to an embodiment of the present invention. DETAILED DESCRIPTION

[0045] As described in the background, the existing technology still has many problems. In one embodiment, the image sensor CMOS itself has a complete packaging structure. However, the surface of the image sensor CMOS has certain microstructures, which makes it difficult to form a filter layer on the microstructured surface, making it difficult to achieve lensless detection of fluorescence signals.

[0046] To address the aforementioned technical issues, the present invention provides a method for forming an image sensor. On the one hand, a filter film is provided to capture light signals in a specific fluorescence band, facilitating subsequent fluorescence imaging experiments using this fluorescence band. This achieves lensless imaging of the fluorescence signal, reduces the cost of fluorescence microscopy, and simplifies the fluorescence microscopy process. On the other hand, the filter film is formed on a flat photoelectric sensitive area, resulting in a uniform thickness across the filter film. This reduces the possibility of diffuse reflection and scattering of the fluorescence signal on the filter film surface due to uneven filter film thickness, and reduces the possibility of significant variations in light intensity collected by the photoelectric sensitive area due to diffuse reflection and scattering, thereby ensuring the reliability of the fluorescence microscopy results.

[0047] In order to make the above-mentioned objects, features and beneficial effects of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0048] FIG1 is a schematic flow chart of a method for acquiring an image sensor according to an embodiment of the present invention.

[0049] Referring to FIG1 , the method for obtaining an image sensor includes the following steps:

[0050] Step S10, obtaining a substrate having a first surface and a second surface opposite to each other, the substrate having a plurality of photoelectric sensitive areas, the first surface exposing surfaces of the photoelectric sensitive areas;

[0051] Step S11, forming a filter film on the photoelectric sensitive area, wherein the filter film allows light signals with a wavelength greater than a preset wavelength to pass through;

[0052] Step S12, forming a fiber optic plate microstructure on the surface of the filter film;

[0053] Step S13, forming a first protective layer on the surface of the filter film and the optical fiber plate microstructure;

[0054] Step S14: After forming the first protective layer, forming a second packaging structure on the surface of the first protective layer, wherein the second packaging structure has a groove for carrying the sample to be tested.

[0055] The following is a detailed description with reference to the accompanying drawings.

[0056] FIG2 is a schematic flow chart of a method for obtaining a substrate in one embodiment of the present invention.

[0057] 4 to 12 are schematic structural diagrams of a process for forming an image sensor according to an embodiment of the present invention.

[0058] Referring to FIG. 1 , step S10 is performed to obtain a substrate 100 having a first surface and a second surface opposite to each other. The substrate 100 has a plurality of photoelectric sensitive regions I, and the first surface exposes the surfaces of the photoelectric sensitive regions I.

[0059] Specifically, in this embodiment, the substrate 100 is an independent chip substrate. Referring to FIG. 1 and FIG. 2 , the method for obtaining the substrate 100 includes the following steps:

[0060] Step S100, providing an initial image sensor, comprising: a substrate having a first surface and a second surface opposite to each other, the substrate having a plurality of photoelectric sensing areas, the first surface exposing surfaces of the photoelectric sensing areas and microlens structures located on the photoelectric sensing areas; the substrate further having an interconnection area, the interconnection area surrounding the plurality of photoelectric sensing areas, the surface of the interconnection area having a plurality of interconnect lines; the initial image sensor further having a first packaging structure, the first packaging structure covering the interconnect lines and the microlens structure, the first packaging structure comprising a glass cover;

[0061] Step S101, removing the glass cover;

[0062] Step S102, removing impurities remaining on the glass cover plate;

[0063] Step S103, forming a second protective layer on the surface of the interconnection line;

[0064] Step S104, removing the microlens structure;

[0065] Step S105: cleaning the surface of the photoelectric sensitive area.

[0066] The following is a detailed description with reference to the accompanying drawings.

[0067] Please refer to Figures 1, 2, 4, and 5. Figure 4 is a top view of Figure 5, and Figure 5 is a schematic cross-sectional view of Figure 4 taken along the XX' direction. The top view does not show the first packaging structure. Step S100 is performed to provide an initial image sensor, including: a substrate 100 having a first surface and a second surface opposing each other. The substrate 100 has a plurality of photosensitive regions I. The first surface exposes the surfaces of the photosensitive regions I and a microlens structure 101 located on the photosensitive regions I.

[0068] The substrate 100 may be made of silicon, silicon carbide, silicon germanium, silicon on insulator (SOI), or germanium on insulator (GOI).

[0069] Each of the photoelectric sensitive areas I is arranged in an array along the second direction and the first direction, and the first direction is perpendicular to the second direction.

[0070] The photoelectric sensing area I is used to collect light signals.

[0071] The size of the photoelectric sensitive area I parallel to the surface of the substrate 100 ranges from 5 mm to 30 mm.

[0072] The photoelectric sensitive area I provides a structural basis for forming the filter film 106 .

[0073] The substrate 100 further has an interconnection region II, which surrounds a plurality of the photoelectric sensitive regions I. A plurality of interconnection lines 102 are formed on the surface of the interconnection region II.

[0074] The interconnection lines 102 are used to connect the wafer and the pins to achieve electrical signal transmission and power transfer between the inside and outside of the chip.

[0075] The interconnection line 102 is made of copper, gold, or platinum.

[0076] The initial image sensor further has a first packaging structure, which covers the interconnection line 102 and the microlens structure 101 . The first packaging structure includes a glass cover 103 .

[0077] In this embodiment, the packaging method of the first packaging structure includes a ceramic leaded chip carrier (CLCC) package.

[0078] In other embodiments, the packaging method of the first packaging structure is other packaging methods.

[0079] The initial image sensor also has a device layer 105 .

[0080] Specifically, in this embodiment, the device layer 105 is located on the second surface of the substrate 100 , and the subsequently formed filter film 106 is located on the first surface of the substrate 100 .

[0081] In other embodiments, the device layer is also located on the first surface of the substrate, and the subsequently formed filter film is located on the surface of the device layer.

[0082] Specifically, in this embodiment, an existing independent chip is purchased and the microlens structure 101 of the existing independent chip is removed. On the one hand, the production cost is reduced; on the other hand, a filter film 106 is formed on the surface of the photoelectric sensitive area I, thereby enhancing the bonding force between the filter film 106 and the surface of the photoelectric sensitive area I.

[0083] Please refer to FIG. 1 , FIG. 2 and FIG. 6 , and perform step S101 to remove the glass cover 103 (as shown in FIG. 5 ).

[0084] Methods for removing the glass cover plate 103 include mechanical removal or thermal removal.

[0085] The glass cover plate 103 is removed in a clean workshop.

[0086] Referring to Figures 1, 2, and 6, step S102 is performed to remove impurities remaining on the glass cover plate 103 after removing the glass cover plate 103. Specifically, in this embodiment, a high-purity gas is used to clean the surface of the substrate 100 to remove the remaining impurities. The high-purity gas includes high-purity nitrogen, high-purity oxygen, or high-purity compressed air.

[0087] When removing the glass cover 103 , the photoelectric sensitive area I must not be damaged to avoid damaging the photoelectric sensitive area I and affecting the performance of the image sensor.

[0088] When removing the glass cover 103 , the interconnection lines 102 must not be damaged to avoid affecting the transmission of electrical signals and power between the inside and outside of the chip.

[0089] After removing the glass cover 103, the surface of the image sensor is observed to confirm the size of the microlens structure 101 on the surface of the image sensor. The observation process is performed using a conventional microscope or a scanning electron microscope. The purpose of the observation process is to determine the size of the microlens structure 101. When the size of the microlens structure 101 is greater than a first threshold, the microlens structure 101 is subsequently removed by mechanical grinding followed by chemical etching or chemical mechanical polishing. When the size of the microlens structure 101 is less than the first threshold, the microlens structure 101 is removed by chemical etching or chemical mechanical polishing.

[0090] Specifically, in this embodiment, the first threshold value is 200 nm. In other embodiments, the first threshold value is other values.

[0091] Please refer to FIG. 1 , FIG. 2 and FIG. 7 , and perform step S103 . After removing the glass cover 103 , a second protective layer 104 is formed on the surface of the interconnection line 102 .

[0092] The second protective layer 104 is high temperature resistant and corrosion resistant, and the forming method of the second protective layer 104 includes curing. The material of the second protective layer 104 includes: UV curing glue, heat curing glue, chemical reaction curing glue and natural curing glue.

[0093] The thickness of the second protection layer 104 ranges from 50 nm to 300 nm.

[0094] The second protective layer 104 has the following functions: on the one hand, it prevents the interconnection line 102 from being damaged and affecting the transmission of electrical signals and power between the inside and outside of the chip; on the other hand, it prevents the reagents of the sample to be tested from contacting the interconnection line 102 to form a short circuit and damage the chip.

[0095] In other embodiments, the second protection layer is formed after the first protection layer is formed.

[0096] Please refer to FIG. 1 , FIG. 2 and FIG. 8 , and perform step S104 . After forming the second protection layer 104 , the microlens structure 101 is removed.

[0097] The method of removing the microlens structure 101 includes: mechanical grinding, chemical etching or chemical mechanical polishing or a combination of one or more of them.

[0098] When the size of the microlens structure 101 is greater than a first threshold, the method for removing the microlens structure 101 includes: mechanically grinding the microlens structure 101; and chemically etching or chemical-mechanical polishing the mechanically ground microlens structure 101 until the surface of the photoelectric sensitive area I is exposed.

[0099] When the size of the microlens structure 101 is smaller than a first threshold, the method for removing the microlens structure 101 includes: chemically etching or chemical mechanical polishing the microlens structure 101 until the surface of the photoelectric sensitive area I is exposed.

[0100] Specifically, in this embodiment, the first threshold value is 200 nm. In other embodiments, the first threshold value is other values.

[0101] The presence of the microlens structure 101 prevents the subsequent film filter 106 from being formed on the flat surface of the photoelectric sensitive area I, resulting in uneven thickness of the film filter 106. Removing the microlens structure 101 allows the subsequent film filter 106 to be formed on the flat surface of the photoelectric sensitive area I, resulting in a uniform thickness across the film filter 106. This reduces the possibility of diffuse reflection and scattering of the fluorescence signal on the surface of the film filter 106 due to uneven thickness, and reduces the possibility of large variations in the light intensity collected by the photoelectric sensitive area I due to diffuse reflection and scattering, thereby ensuring the reliability of the fluorescence microscopy results.

[0102] Please refer to FIG. 1 , FIG. 2 and FIG. 8 , and perform step S105 , in which the surface of the photoelectric sensing area I is cleaned after removing the microlens structure 101 .

[0103] The surface of the photoelectric sensitive area I is cleaned in a clean workshop, and the cleaning solvent includes: a combination of one or more of sodium hydroxide, hydrochloric acid, ethanol or isopropyl alcohol.

[0104] In another embodiment, the substrate is a wafer. Referring to FIG. 1 and FIG. 3 , the method for obtaining the substrate includes the following steps:

[0105] Step S1000, developing a corresponding semiconductor process based on the wafer;

[0106] Step S1001: forming a plurality of photoelectric sensitive areas.

[0107] When the substrate is a wafer, in one embodiment, a device layer is subsequently formed on the first surface of the substrate; and a filter film is formed on the surface of the device layer.

[0108] When the substrate is a wafer, in another embodiment, a device layer is subsequently formed on the second surface of the substrate; and a filter film is formed on the first surface of the substrate.

[0109] After obtaining the substrate 100 , please refer to FIG. 1 and FIG. 9 to perform step S11 . In this embodiment, a filter film 106 is formed on the first surface of the substrate 100 .

[0110] The method for forming the filter film 106 includes: obtaining parameters of the filter film 106 ; and forming the filter film 106 using the parameters of the filter film 106 .

[0111] The method for obtaining the parameters of the filter film 106 includes: obtaining the required light band, the optical parameters of the light band including the excitation light source wavelength peak and the excitation light source wavelength bandwidth; obtaining the filter film material; and obtaining the parameters of the filter film based on the filter film material and the optical parameters.

[0112] The method for obtaining the required light band includes: obtaining the required light band by obtaining the wavelength of the fluorescent dye required for detection.

[0113] The fluorescent dye includes: fluorescein or quantum dots; the wavelength range of the fluorescent dye is: 468nm~508nm (488+ / -20nm).

[0114] The preset wavelength range of the optical signal allowed to pass through by the filter film 106 is: 488nm ~ 700nm.

[0115] The preset wavelength bands of the optical signals allowed to pass through by the filter film 106 include: light wavelengths greater than 488 nm, light wavelengths greater than 520 nm, or light wavelengths greater than 660 nm.

[0116] In this embodiment, the filter film 106 is a long-pass filter film.

[0117] The material of the filter film 106 includes metal oxide or non-metal oxide. The metal oxide includes titanium oxide, zirconium oxide or aluminum oxide. The non-metal oxide includes silicon oxide.

[0118] The method for obtaining the parameters of the filter film 106 includes: using simulation software to input a preset wavelength of the light signal allowed to pass, thereby obtaining the parameters of the filter film 106. The simulation software includes: Zemax, Comsol or FDTD solutions.

[0119] The parameters of the filter film 106 include the number of filter film layers and the thickness of the filter film.

[0120] The number of layers of the filter film 106 ranges from 10 to 20 layers; the thickness of the filter film 106 ranges from 5 μm to 20 μm.

[0121] The method for forming the filter film 106 includes: spin coating of light-absorbing dye, target magnetron sputtering or vapor deposition.

[0122] The equipment for forming the filter film 106 includes: a plasma surface treatment machine, a coating machine, a magnetron sputtering machine or a combination of one or more of a vacuum drying oven.

[0123] The filter film 106 can be set to obtain light signals of a specific fluorescence band, which is convenient for subsequent fluorescence imaging experiments using this fluorescence band. This realizes lensless imaging of fluorescence signals, reduces the cost of fluorescence microscopy, and simplifies the fluorescence microscopy process.

[0124] After forming the filter film 106 , the method further includes: testing and characterizing the filter film 106 . The testing and characterization includes: uniformity testing of the filter film 106 and spectral transmittance testing of the filter film 106 .

[0125] The uniformity test of the filter film 106 includes: a flatness test of the filter film 106 and a roughness test of the filter film 106 .

[0126] The spectral transmittance test standard of the filter film 106 includes: the spectral transmittance of the filter film 106 is greater than 95%.

[0127] Please refer to FIG. 1 and FIG. 10 , and execute step S12 . After forming the filter film 106 , a fiber optic plate microstructure 107 is formed on the surface of the filter film 106 .

[0128] The method for forming the optical fiber plate microstructure 107 includes:

[0129] The material of the optical fiber plate microstructure 107 includes: forming an initial optical fiber plate microstructure (not shown) on the surface of the filter film 106; and performing micro-nano processing on the initial optical fiber plate microstructure to form the optical fiber plate microstructure 107.

[0130] The thickness of the optical fiber plate microstructure 107 ranges from 50 nm to 100 nm.

[0131] The size of the optical fiber plate microstructure 107 parallel to the surface of the substrate 100 ranges from 5 mm to 30 mm.

[0132] The function of the optical fiber plate microstructure 107 is to make the fluorescent signal incident on the surface of the photoelectric sensitive area I in a vertical direction, reduce the possibility of scattering of the fluorescent signal, make the light intensity collected by the photoelectric sensitive area I uniform, and ensure the reliability of fluorescence microscopy detection.

[0133] Please refer to FIG. 1 and FIG. 11 , and perform step S13 . After the optical fiber plate microstructure 107 is formed, a first protective layer 108 is formed on the surface of the optical fiber plate microstructure 107 .

[0134] The material of the first protective layer 108 includes silicon dioxide, titanium dioxide or zirconium dioxide.

[0135] The thickness of the first protective layer 108 ranges from several micrometers to more than ten micrometers.

[0136] The first protective layer 108 is used to protect the filter film 106 and the optical fiber plate microstructure 107 to prevent the filter film 106 and the optical fiber plate microstructure 107 from being damaged.

[0137] After forming the first protective layer 108 , the method further includes testing and characterizing the filter film 106 , including the cutoff efficiency of the filter film 106 for light of corresponding wavelengths and the overall uniformity of the filter film 106 .

[0138] The test standard for the cutoff efficiency of the filter film 106 for light of corresponding wavelengths includes: the cutoff efficiency of the filter film 106 is greater than 99.9%.

[0139] The test contents of the overall uniformity of the filter film 106 include: a flatness test of the filter film 106 and a roughness test of the filter film 106 .

[0140] 1 and 12 , step S14 is performed. After forming the first protective layer 108 , a second packaging structure 109 is formed on the surface of the first protective layer 108 . The second packaging structure 109 has a groove (not shown) for carrying a sample to be tested.

[0141] The second packaging structure 109 is made of silicon and quartz glass.

[0142] The depth of the groove ranges from 20 μm to 100 μm.

[0143] Correspondingly, an embodiment of the present invention further provides an image sensor, please continue to refer to Figure 12, including: a substrate 100, having a first surface and a second surface relative to each other, the substrate 100 having a plurality of photoelectric sensitive areas I, the first surface exposing the surface of the photoelectric sensitive areas I; a filter film 106 located on the photoelectric sensitive areas I, the filter film 106 allowing light signals greater than a preset wavelength to pass through; and a first protective layer 108 located on the surface of the filter film 106.

[0144] The image sensor includes a substrate 100 having a first surface and a second surface opposite to each other. The substrate 100 has a plurality of photoelectric sensitive regions I. The first surface exposes the surfaces of the photoelectric sensitive regions I.

[0145] The substrate 100 may be made of silicon, silicon carbide, silicon germanium, silicon on insulator (SOI), or germanium on insulator (GOI).

[0146] Each of the photoelectric sensitive areas I is arranged in an array along the second direction and the first direction, and the first direction is perpendicular to the second direction.

[0147] The size of the photoelectric sensitive area I parallel to the surface of the substrate 100 ranges from 5 mm to 30 mm.

[0148] The substrate 100 further has an interconnection region II, which surrounds a plurality of the photoelectric sensitive regions I. A plurality of interconnection lines 102 are formed on the surface of the interconnection region II.

[0149] The interconnection line 102 is made of copper, gold, or platinum.

[0150] The image sensor includes: a second protective layer 104 located on the surface of the interconnection line 102; the thickness of the second protective layer 104 ranges from:; the material of the second protective layer 104 includes: UV curing glue, thermal curing glue, chemical reaction curing glue and natural curing glue.

[0151] The image sensor includes a filter film 106 located on the photoelectric sensing area I, and the filter film 106 allows light signals with a wavelength greater than a preset wavelength to pass through.

[0152] The preset wavelength range of the optical signal allowed to pass through by the filter film 106 is: 488nm ~ 700nm.

[0153] The preset wavelength bands of the optical signals allowed to pass through by the filter film 106 include: light wavelengths greater than 488 nm, light wavelengths greater than 520 nm, or light wavelengths greater than 660 nm.

[0154] The material of the filter film 106 includes metal oxide or non-metal oxide. The metal oxide includes titanium oxide, zirconium oxide or aluminum oxide. The non-metal oxide includes silicon oxide.

[0155] The number of layers of the filter film 106 ranges from 10 to 20 layers; the thickness of the filter film ranges from 5 μm to 20 μm.

[0156] The image sensor includes a first protective layer 108 located on a surface of the filter film 106 .

[0157] The material of the first protective layer 108 includes silicon dioxide, titanium dioxide or zirconium dioxide; the thickness of the first protective layer 108 ranges from several micrometers to more than ten micrometers.

[0158] The image sensor includes: a fiber optic plate microstructure 107 located between the filter film 106 and the first protective layer 108; the material of the fiber optic plate microstructure 107 includes: silicon dioxide or titanium dioxide; the thickness range of the fiber optic plate microstructure 107 is: 50nm~100nm; the size range of the fiber optic plate microstructure 107 parallel to the surface of the substrate 100 is: 5mm~30mm.

[0159] The image sensor includes a second packaging structure 109 located on the surface of the first protection layer 108 . The second packaging structure 109 has a groove (not shown) for carrying a sample to be tested.

[0160] The second packaging structure 109 is made of silicon and quartz glass.

[0161] The depth of the groove ranges from 20 μm to 100 μm.

[0162] In this embodiment, the image sensor further includes: a device layer 105 located on the second surface of the substrate 100 .

[0163] In other embodiments, the image sensor includes: a device layer located on the surface of the first side of the substrate; and the filter film is located on the surface of the device layer.

[0164] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope defined by the claims.

Claims

1. An image sensor, characterized in that: include: A substrate having a first surface and a second surface opposite to each other, the substrate having a plurality of photoelectric sensitive areas, the first surface exposing the surface of the photoelectric sensitive areas; A filter film located on the photoelectric sensitive area, the filter film allowing light signals with a wavelength greater than a preset wavelength to pass through; A first protective layer is located on the surface of the filter film.

2. The image sensor according to claim 1, wherein: Also includes: A device layer located on the surface of the first side of the substrate, or a device layer located on the surface of the second side of the substrate; The filter film is located on the surface of the device layer.

3. The image sensor according to claim 1, wherein: It also includes: a fiber optic plate microstructure located between the filter film and the protective layer; the material of the fiber optic plate microstructure includes: silicon dioxide or titanium dioxide; the thickness range of the fiber optic plate microstructure is: 50nm ~ 100nm.

4. The image sensor according to claim 1, wherein: The substrate also has an interconnection area, which surrounds the plurality of photoelectric sensitive areas, and a surface of the interconnection area has a plurality of interconnection lines.

5. The image sensor according to claim 4, wherein: It also includes: a second protective layer located on the surface of the interconnection line; the thickness of the second protective layer ranges from 50nm to 300nm; and the material of the second protective layer includes silicon.

6. The image sensor according to claim 1, wherein: Also includes: A second packaging structure is located on the surface of the first protective layer, and the second packaging structure has a groove for carrying a sample to be tested.

7. The image sensor according to claim 1, wherein: Also includes: The material of the filter film includes: metal oxide or non-metal oxide; the metal oxide includes: titanium oxide, zirconium oxide or aluminum oxide; the non-metal oxide includes silicon oxide; the thickness range of the filter film is: 5μm to 20μm.

8. The image sensor according to claim 1, wherein: Also includes: The material of the first protective layer includes silicon dioxide, titanium dioxide or zirconium dioxide; the thickness of the first protective layer ranges from 5 nm to 20 nm.

9. The image sensor according to claim 1, wherein: The preset wavelength range of the optical signal allowed to pass through the filter film is: 488nm~700nm, and the preset wavelength band of the optical signal allowed to pass through the filter film includes: light wave wavelength greater than 488nm, light wave wavelength greater than 520nm or light wave wavelength greater than 660nm.

1. A method for forming an image sensor, characterized in that: include: Obtaining a substrate having a first surface and a second surface opposite to each other, the substrate having a plurality of photoelectric sensitive areas, the first surface exposing the surface of the photoelectric sensitive areas; forming a filter film on the photoelectric sensitive area, wherein the filter film allows light signals with a wavelength greater than a preset wavelength to pass through; A first protective layer is formed on the surface of the filter film.

11. The method for forming an image sensor according to claim 10, wherein: The base is a wafer substrate, and the method for obtaining the base includes: developing a corresponding semiconductor process based on the wafer to form a plurality of the photoelectric sensitive areas.

12. The method for forming an image sensor according to claim 10, wherein: The substrate is an independent chip substrate, and the method for obtaining the substrate includes: providing an initial image sensor, including: a substrate having a first surface and a second surface relative to each other, the substrate having a plurality of photoelectric sensitive areas, the first surface exposing the surface of the photoelectric sensitive area and the microlens structure located on the photoelectric sensitive area; removing the microlens structure.

13. The method for forming an image sensor according to claim 11, wherein: Also includes: forming a device layer on the first surface or the second surface of the substrate; A filter film is formed on the surface of the device layer.

14. The method for forming an image sensor according to claim 12, wherein: Also includes: A device layer located on the first surface or the second surface of the substrate; A filter film is formed on the surface of the device layer.

15. The method for forming an image sensor according to claim 12, wherein: The substrate also has an interconnection area, which surrounds the plurality of photoelectric sensitive areas, and a surface of the interconnection area has a plurality of interconnection lines.

16. The method for forming an image sensor according to claim 15, wherein: The initial image sensor also has a first packaging structure, the first packaging structure covers the interconnection line and the microlens structure, and the first packaging structure includes a glass cover.

17. The method for forming an image sensor according to claim 16, wherein: Before removing the microlens structure, the method further includes: removing the glass cover plate; the method of removing the glass cover plate includes: mechanical removal or thermal processing removal.

18. The method for forming an image sensor according to claim 17, wherein: After removing the glass cover plate and before removing the microlens structure, the method further includes: forming a second protective layer on the surface of the interconnection line.

19. The method for forming an image sensor according to claim 18, wherein: After removing the glass cover plate and before forming the second protective layer, the method further includes: removing impurities remaining on the glass cover plate.

20. The method for forming an image sensor according to claim 12, wherein: The method of removing the microlens structure includes: mechanical grinding, chemical etching or chemical mechanical polishing or a combination of one or more of them.

21. The method for forming an image sensor according to claim 12, wherein: After removing the microlens structure and before forming the filter film, the method further includes: cleaning the surface of the photoelectric sensitive area.

22. The method for forming an image sensor according to claim 10, wherein: The method for forming a filter film comprises: obtaining parameters of the filter film; and forming the filter film using the parameters of the filter film.

23. The method for forming an image sensor according to claim 22, wherein: The method for obtaining the parameters of the filter film includes: obtaining the required light band, the optical parameters of the light band include the excitation light source wavelength peak and the excitation light source wavelength bandwidth; obtaining the filter film material; obtaining the parameters of the filter film according to the filter film material and the optical parameters, the parameters of the filter film include the number of filter film layers and the thickness of the filter film.

24. The method for forming an image sensor according to claim 10, wherein: The method for forming the filter film includes: spin coating of light-absorbing dye, target magnetron sputtering or vapor deposition.

25. The method for forming an image sensor according to claim 10, wherein: After forming the filter film and before forming the first protective layer, the method further includes: forming a fiber optic plate microstructure on the surface of the filter film.

26. The method for forming an image sensor according to claim 25, wherein: The method for forming the optical fiber plate microstructure comprises: forming an initial optical fiber plate microstructure on the surface of the filter film; and performing micro-nano processing on the initial optical fiber plate microstructure to form the optical fiber plate microstructure.

27. The method for forming an image sensor according to claim 10, wherein: After forming the first protective layer, the method further includes: forming a second packaging structure on the surface of the first protective layer, wherein the second packaging structure has a groove for carrying a sample to be tested.

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